WO1994000306A1

WO1994000306A1 - Position sensor and uses thereof

Info

Publication number: WO1994000306A1
Application number: PCT/FR1993/000631
Authority: WO
Inventors: Michaël GOULET
Original assignee: Innovation Technologique Appliquee (I.T.A.)
Priority date: 1992-06-24
Filing date: 1993-06-24
Publication date: 1994-01-06
Also published as: AU4334093A

Abstract

Sensor for determining the relative position of two rotating members of a vehicle, said rotating members being the wheel rim (3B) and the tread (39) of the tyre (2) associated with the wheel, the position sensor being partially carried by the wheel rim (3B) and partially disposed within the tyre (2) which also contains an electric power supply for the sensor. The position sensor comprises a pin (13) located in the tyre (2).

Description

POSITION SENSOR AND USES OF SUCH A SENSOR

The present invention relates to a position sensor as well as various uses of said position sensor, in particular applied to motor vehicles.

The development of electronics in motor vehicles today allows greater finesse of controls or adjustments in the main functions of the vehicle, such as propulsion, braking, road handling, these major functions obviously contributing to safety. This finesse of commands or settings obviously requires sensors of high precision and short response time, to allow true control of the function, this in an aggressive environment, said sensors having to be moreover a low cost price. . Sensors satisfying all the criteria mentioned above do not exist today, in particular sensors for the relative position of two members, and this is a drawback. The invention aims to overcome this drawback.

In the application to motor vehicles, there is provided such a sensor for more particularly measuring the relative position of two members driven in a rotational movement, a transmitter being disposed between one of the rotating members and a non-rotating support supporting said member. rotating, to transmit information from the sensor to the vehicle user. According to a preferred use, in accordance with the present invention, the rotating members are the rim of the wheel of the motor vehicle, and the tread of the tire associated with the wheel, the position sensor being partially carried by the rim and partially contained at inside the vehicle tire which also contains an electrical supply for the sensor.

The position sensor comprises a needle arranged inside the wheel, a position detector for detecting the position of the needle inside the wheel, a transmitter being provided for transmitting the information from the position detector to a fixed, non-rotating part of the vehicle, said information being representative of the deformation of the tire with respect to the rim. The needle is made up of at least two cylindrical parts mounted to slide one inside the other, of electrically insulating material, at least two conductive traces extending longitudinally and electrically connected to an electrical circuit for using the sensor, and a conductive trace, located opposite the two said longitudinal traces and adapted to come into contact with the longitudinal traces when one of the two parts moves inside the other, each of the two parts being linked at least by contact with each of said members whose relative position is to be measured; the two longitudinal conductive traces are carried by the surface of one of the parts, and the opposite trace is annular and carried by the other part on its face situated opposite the longitudinal traces; said conductive traces constitute the needle position detector.

Preferably, the longitudinal traces are carried by the outer face of a part which slides in the other part.

Advantageously, each of the longitudinal conductive traces crosses the wall of the part which carries it and is connected to a connection pin, a plug, made of insulating material, carrying the pins which are connected to conductors passing through the plug and folded down to the external surface. of the plug, the plug being force fitted into the part with longitudinal traces which are, in this position of the plug, in contact with the conductors; one of the two members carries two metal pins complementary to the pins of the needle. Preferably, the annular conductive trace is adapted to come into contact with the longitudinal traces by means of balls trapped in the part carrying the annular trace; the longitudinal tracks are provided on longitudinal grooves in which the balls slide. According to a preferred embodiment, the two parts are slidably sealed and define a sealed chamber in which a pressurized fluid biases them in extension.

Advantageously, the annular and longitudinal traces being in contact, they close an electrical circuit in which an electric current flows; the annular and longitudinal traces are arranged to behave like a potentiometer in their relative longitudinal movement.

Preferably, the connection of the needle to one of the two members is carried out by an elastic bellows membrane, one end of which is integral with a part of the needle, said membrane being housed in a cylindrical housing of said member, and having at rest a position of minimum length towards which it is recalled by its own elasticity, said housing being of sufficient length to receive the membrane in the rest position and the needle in the retracted position, the interior chamber of the membrane being in communication with the sealed chamber inside the needle, so that when the inside of the needle is subjected to the action of the fluid under pressure, the membrane is expanded in the housing and the needle is in extension and out of the housing. Such a position sensor has a very short reaction time, and its precision can be easily adapted to requirements, since it suffices for this to put the number of longitudinal traces offset which is suitable.

Advantageously, the transmitter comprises an annular insulating disc integral in rotation with the rotating member, centered on the axis of said rotating member, and carrying on one of its faces at least two concentric electrically conductive circular tracks, each connected to a conductor electric carried by the disc and connected to a connection means for being connected to an electric cable having at least two conductors, the transmitter further comprising at least one roller made of insulating material, cylindrical and of circular section, said roller having at least two metal inserts projecting, on the one hand, relative to a front face of said roller, to cooperate in electrical contact with the tracks of the disc, and, on the other hand, relative to the cylindrical outer surface of the roller, to cooperate in electrical contact with annular grooves coated with a conductive material provided on the surface of a raceway made of insulating material, for rté by the support and on which the roller rolls, means being provided for driving the roller by the disc. When the sensor has a sealed chamber in which a pressurized fluid urges it in extension, the fluid is the compressed air prevailing in the tire; preferably, a conduit connects the interior of the membrane to the tire inflation valve. According to a variant, the sensor is at least partially integrated in the tire inflation valve. According to a preferred embodiment of the invention, the needle consists of a lever articulated on the rim at one of its ends; the other end of the lever is in contact with the inner face of the tire tread against which it is elastically urged. The needle position is detected by a second lever articulated on the lever which cooperates with a detector.

The detector comprises an insulating support integral with the rim and the bottom of which carries conductive pads and a conductive bar, a shoe being slidably mounted in the support and carrying a wiper adapted to cooperate with each of the pads and a wiper cooperating permanently with the barette, the two wipers being electrically connected.

Alternatively, the detector comprises a support having a longitudinal groove on each side of which are arranged transmitter-receiver pairs of a light barrier fork sensor, a carriage coupled to the second lever being mounted to slide relative to the support and carrying a tail sliding in the groove and able to obscure, or not, the transverse space separating the transmitter and the receiver from a pair. As a variant, the detection of the position of the needle is carried out by a sensor detecting the angular position of the needle around its articulation; the sensor is carried by the rim and sensitive to the action of a finger carried by the lever; it is of the Hall effect type sensitive to the action of a magnetic field created by a magnet secured to the needle and carried by the finger.

The signal supplied by the sensor is amplified by an amplifier; the output of the amplifier is connected to the input of an analog-digital converter; the converter has outputs corresponding to categories in which it classifies the output signal of the amplifier; each converter output corresponding to each category is connected to a solid-state winding the rim of the wheel; a transmitter comprises as many transmission sensors as there are categories; each transmission sensor is sensitive to the magnetic field created by each winding; each sensor is a Hall effect module. The information conducted on the dashboard is translated by an electronic module which only translates information on all the information it receives during a wheel revolution.

According to a variant, the articulation of the needle is a ball joint; the end of the lever in contact with the internal face of the raceway moves on this face between two circumferential ribs provided on the internal surface of said tread; the position detector for the lever not only detects the position of the lever with respect to the articulation in a plane perpendicular to the axis of the wheel but also its position relative to this plane.

The transmitter comprises a fixed part and a mobile part; the movable part is an insulating disc comprising circular metal tracks in number equal to the number of pellets of the detector plus a track; the tracks are integral with a conductor, these conductors being connected to a connector for connection to the pellets and the bar; the fixed part of the transmitter is an insulating part carrying a nut in which are housed friction shoes cooperating with the tracks of the disc; the fixed part carries a connector for connecting the tracks of the disc to an indicator means available to the user inside the vehicle.

Advantageously, an electrical supply to the electrical circuit is integral in rotation with one of the two rotating members, the transmitter being of the contactless type and consisting of two parts, one of which is integral with said rotating member and the other with the support. Preferably, the power supply is a chargeable accumulator; the power supply is charged by a solar collector secured to one of the two rotating members; the supply is charged by a piezoelectric quartz put in compression by the displacement of the needle. Advantageously, the information transmitted by the transmitter is used to deliver to the driver of the vehicle a information representative of the pressure inside the tire.

The invention also provides for the use of such a sensor in which the information transmitted by the transmitter is used to modulate the braking of the wheel.

As a variant, the invention provides for the use of such a sensor in which the information transmitted by the transmitter is used for controlling the suspension of the vehicle; advantageously, several needles are provided distributed circumferentially around the axis of the rim of the wheel, the transmitter comprises as many rollers as there are needles; two needles are offset axially along the axis of the wheel.

When the vehicle is equipped on each wheel with a damping element with a controlled length, the indication of the needle is advantageously used to vary the length of the damping element.

To better understand the object of the invention, we will now describe, by way of purely illustrative and nonlimiting example, an embodiment shown in the accompanying drawing. In these drawings:

- Figure 1 shows, in partial section, a motor vehicle wheel;

- Figure 2 shows, on a larger scale, a detail, in section, of Figure 1, and in particular the needle 13; - Figure 2 A is, on a larger scale, a view showing a detail of part 5 of Figure 2;

- Figure 3 shows, on a larger scale, a detail, in section, of Figure 1, and in particular the transmitter 14;

- Figure 3A shows an enlarged detail of Figure 3; - Figure 4 is a partial end view of the transmitter according to Figure 3;

- Figure 5 partially shows, in side view, the disc 20 of the transmitter 14, and schematically its connection to the cable 17;

- Figures 6 to 8 schematically show an electrical circuit in the application of the invention to the verification of the inflation pressure of the tire; - Figure 9 shows, in partial section, a motor vehicle wheel, of the kind of that of Figure 1, in the tire of which two needles 13 are offset axially along the axis of the wheel; - Figure 10 shows a detail of an alternative embodiment of the sensor traces;

- Figure 1 1 schematically shows an alternative assembly of the needle.

- Figure 12 is similar to Figure 1 but relates to a variant;

- Figure 13 schematically shows the electrical circuits of the variant of Figure 12;

- Figure 14 is an alternative electrical diagram;

- Figure 15 is an end view of the fixed part of the transmitter corresponding to Figure 14;

- Figure 16 is a partial view, in section, of a motor vehicle wheel fitted with a variant needle according to the invention;

- Figure 17 to 19 are partial views in section through a diametrical plane of the wheel of Figure 16 showing mounting details of the needle according to Figure 16 and its associated position detector;

- Figure 20A is a section through the axis of the wheel of Figure 16 of a portion of the position detector of the variant of Figure 16;

- Figure 20B is similar to Figure 20A, the section plane being offset from that of Figure 20A;

- Figure 21 shows schematically developed circumferentially the part of Figure 20 of the position detector; - Figures 22 and 23 show, respectively in section and axially, the location of the fixed part of the transmitter associated with the variant of the sensor of Figures 16 to 21, Figure 22 being a section along XXII-XXII of Figure 23 ;

- Figures 24 and 25 show, in section and partially in plan, the movable part of the transmitter associated with the variant of the sensor of FIGS. 16 to 21, FIG. 24 being a section along XXIV-XXIV of FIG. 25;

- Figure 26 is a sectional view similar to Figure 20 but relates to a variant; - Figure 27 is a partial sectional view along

XXVII-XXVII of figure 26.

- Figure 28 is a partial view similar to Figure 16 and relates to a variant;

- Figure 29 partially shows the electrical diagram for the operation of the variant of Figure 28;

FIG. 30 schematically shows the layout of the windings and modules of FIG. 29.

Figure 1 shows, in partial section, a front wheel 3 of a motor vehicle; a tire 2, without an inner tube, is received with sealing by a rim 3B carried by a flange 3 A fixed by screws, as known per se, to the web 18A of a hub 18 crossed by a wheel shaft 9 and carried by a pivot 26; the hub 18 is mounted for rotation on the pivot 26 by means of bearings 35; the web 18A of the hub 18 also carries a braking disc 4; a vehicle wheel is well known and will therefore not be described further.

In the rim 3B is formed a cylindrical housing 6, for example of circular section, visible in FIG. 2, extending towards the axis of the wheel, in the vertical median plane of the rim 3B, and having a bottom pierced d 'A hole 6A of diameter smaller than that of the housing, said hole 6A being traversed with sealing by two conductive pins 15 and 16 insulated from each other and from the rim 3B, for example by a filling of insulating plastic 37 also ensuring said sealing. The pins 15 and 16 protrude internally and externally on either side of the filling material 37, and thus constitute both outside and inside two male pins for electrical connection.

A needle 13 of variable length consists, in the example shown, of two cylindrical parts 5 and 10, the outer part 10, relative to the axis of the wheel, being slidably mounted on the part 5. The part 5 is present in the form of a sleeve whose cross section is equal, apart from the mounting clearance, to the cross section of the housing 6; part 5 is made of insulating material; on its outer face, it carries two conductive traces 7 and 8, extending longitudinally over a certain axial length of the part 5 but not over the entire length; the traces 7 and 8 extend inside the part 5, downwards with respect to FIG. 2, after having crossed the wall of the part 5, as shown in FIG. 2A; at one of its ends, a plug 40 is force-fitted into part 5; the plug 40 carries two inserts in the form of female pins 15A and 16A, complementary to the male pins 15 and 16, and intended to cooperate with these; the female pins 15A and 16A are connected to conductors 15B and 16B folded over the outer surface of the plug 40; when the plug 40 is in place in part 5, each of the flaps of the conductors 15B and 16B are in electrical contact with one of the traces 7 and 8; thus, when the part 5 of the needle 13 is mounted in the housing 6 of the rim 3B, each of the tracks 7 and 8 is electrically connected to the male pins 15 and 16 respectively carried by the rim 3B. Such an arrangement allows the mounting or dismounting of the needle 13 relative to the rim, and thus facilitates the mounting or dismounting of the tire. Of course, the mounting of the part 5 on the rim can be carried out in different ways; for example, the housing 6 can be replaced by a stud radially external to the rim 3B, extending towards the interior of the tire, on which the part 5 is fitted. The part 10 of the external needle 13, by relative to the axis of the wheel, slidably mounted on part 5, is also made of insulating material and carries on its periphery internally an annular trace 12 conductive; the mounting is such that, depending on the relative axial position of the parts 5 and 10, the traces 7 and 8 are brought into electrical relationship by the annular trace 12, or not; the part 10 has its curved end to facilitate its contact with the interior wall of the tire.

When the wheel turns, the needle 13 is subjected to a sufficient centrifugal force so that it is in extension; of course, means can be provided to ensure this extension independently of the centrifugal force. For example, the two parts 5 and 10 can be slidably sealed to define a sealed chamber, inside the needle, in which a pressurized fluid biases them in extension.

In a variant not shown, the sealed chamber is in communication with an elastically deformable enclosure, also sealed, the elastic resistance of at least one wall of said enclosure maintaining the pressure in the chamber and the elastic deformation of this same wall allowing movement easy relative of the two parts of the needle; in a variant of this type, the displacement of said wall being an image of the length of the needle 13, the traces 7, 8 and 12 are placed at the right of the sealed enclosure instead of being at the right of the needle 13.

FIG. 11 shows another variant in which the needle is of the type with a sealed chamber; in this figure, moreover, it can be seen that the connection of the needle 13 to one of the two members is produced by an elastic bellows membrane 49, one end of which is integral with the part 5 of the needle 13, said membrane 49 being housed in a cylindrical housing 86 of said member, and having at rest a position of minimum length towards which it is recalled by its own elasticity, said housing 86 being of sufficient length to receive the membrane 49 in the rest position and l needle 13 in the retracted position, the inner chamber of the membrane being in communication with the sealed inner chamber of the needle 13, so that when the inside of the needle 13 is subjected to the action of the fluid under pressure, the membrane 49 is expanded in the housing 86 and the needle 13 is in extension and out of the housing 86; this arrangement facilitates the dismantling of the tire by erasing the needle in the housing of the rim; the initial pressurization of the interior chamber with the needle 13 and that of the membrane 49 is carried out by means of a conduit 88 which connects the interior of the membrane 49 to the inflation valve of the tire; advantageously, when the inflation is finished, the closing of the valve of the tire ensures at the same time the isolation of the chamber of the membrane from the interior of the tire, to make the pressures prevailing in the tire and in the membrane independent. . An information transmitter 14, disposed between two parts, one fixed and the other mobile, comprises an annular disc 20 maintained (FIG. 1) on the inner face of the web 18A of the hub 18; the disc 20 is therefore driven in rotation with the vehicle wheel; such a disc 20 is made of insulating material and carries (FIG. 5) on one of its faces two concentric circular tracks 21 and 22 each connected respectively by a conductor 23, 24 embedded in the disc and connected to a visible connection means 41 on the other face of the disc 20; when the disc is in place on the hub 18, the connection means 41 cooperates with complementary connection means carried by a pin 19 (FIG. 1), also made of insulating material, crossed by two conductors each thus being electrically connected to each circular tracks 21, 22 of the disc 20. The pin 19 passes through the web 18A of the hub 18, and that of the disc 4, as well as the flange 3 A of the wheel, in the manner of a wheel positioning pin for its mounting, such an arrangement usually facilitating the mounting and dismounting of said wheel. A two-conductor electric cable 17 carries at each of its ends a connector, namely a connector 25 for mounting the cable on the pin 19 and a connector 38 for mounting on the pins 15 and 16 of the rim 3B: it will be understood that 'thus the conductive traces 7 and 8 of the needle 13 are in electrical connection with the circular tracks 21, 22 of the disc 20.

The transmitter 14 also comprises (FIG. 3) a cylindrical roller 36 of circular section consisting of an insulating cylinder having two concentric metal inserts in the form of hollow rivets; each insert comprises, on the one hand, a cylindrical portion 29, 30 extending along the longitudinal axis of the roller 36 and slightly projecting with respect to a front face 42 of said roller 36, and, on the other hand, a collar 29A, 30A terminating peripherally by a return 29B, 30B in the form of a V projecting with respect to the cylindrical external surface of the roller 36. The roller 36 is caused to roll on an inner annular raceway 27 fixed annular centered on the axis of the hub 18 and carried by a sleeve 46 which has the pivot 26 and which defines an annular space 48 occupied, as known per se, by a seal disposed between the pivot 26 and the hub 18, outwardly relative to to the bearings 35. The internal raceway 27 also in insulating material has on its outer surface two annular grooves of V-shaped section coated with a conductive material 50, 51, said V being slightly more open than the V of the returns 29B, 30B of the collars 29A, 30A of the inserts of the roller 36 , said returns 29B, 30B being caused to roll in the grooves of the inner raceway 27 when the roller 36 rolls on said inner raceway 27; this arrangement ensures good electrical contact between said returns 29B, 30B and the coverings 50, 51. Conductors 31, 32 embedded in the inner raceway 27 connect the conductive materials 50 and 51 to two external conductors 33, 34 via a connector radial diagrammatic at 53 carried by a radial protuberance 54 of the inner raceway 27, the protuberance 54 and the conductors 33, 34 being housed in a radial groove 47 of the pivot 26.

The drive of the roller 36 is provided by an axial housing 44 of circular section formed in the disc 20 in the center of the circular tracks 21, 22, said housing 44 receiving a stud 45, also of circular section, carried by the roller 36 according to its axis and projecting from its end face 42.

The transmitter 14 ensures that the conductors 33, 34 are electrically connected to the tracks 7 and 8 of the needle 13 while the wheel rotates: in fact, the circular tracks 21, 22 of the disc 20 are, as we have seen, in electrical connection with said traces 7 and 8 of the needle 13; the cylindrical portions 29 and 30 of the inserts of the roller 36, of the same diameter as the circular tracks 21, 22 of the disc 20, urged into contact with them by elastic means not shown, remain in contact with these tracks 21, 22, by turning on itself when the disc 20, rotating with the hub 18, drives the roller 36 by the connection 44 and 45, and forces it to roll on the inner raceway 27; throughout this bearing, the returns 29B, 30B of the roller 36 roll in the grooves of the inner raceway and are in contact with the coverings 50, 51 of the inner raceway 27, therefore in connection with the conductors 33, 34; an outer raceway 43 completes the transmitter in the manner of a needle bearing; of course, as a variant, this external raceway 43 could include grooves coated with conductive material and also transmit information; of even, the two raceways, interior and exterior, could transmit information.

FIGS. 6 to 8 schematically show an application of the transmitter 14 and of the needle 13 for checking the inflation pressure of the tire 2. The radial height of the tire, that is to say the height measured between the rim 3B and the inner face of the rolling area 39 on the ground of the tire, being a very representative image of the inflation pressure, the invention provides for a measurement of this height and the triggering of an alarm signal when it reaches a critical threshold ; to do this, the annular trace 12 of the part 10 of the needle 13 is positioned so that when it reaches, during the retraction of the needle, in rolling, at the lowest point facing the ground, the traces 7 and 8 of part 5 of the needle, the total length of the needle corresponds to the radial alert height for the tire; FIG. 6 schematically partially shows the open electrical circuit for supplying a control lamp 43, under normal conditions, the annular trace 12 being distant from traces 7 and 8; when the alert rating is reached, the annular trace 12 meets traces 7 and 8 and the lamp 43 lights up, as shown in FIG. 7; it will be noted that when driving, the deformation of the tire in contact with the ground, which ceases at other points, in particular at the diametrically opposite point, leads to a periodic variation in the length of the needle and therefore to an automatic flashing of the lamp 40, thus retaining the attention of the driver of the vehicle more strongly.

According to the variant of FIG. 8, the part 5 of the needle 13 internally carries a trace 57 opposite several traces, three in the example shown, 58, 59, 60; a transmitter 64, the disc, the roller and the inner cage of course respectively comprising four circular tracks similar to 21, 22, four returns similar to 29B, 30B and four materials similar to 50, 51 in grooves, provides the electrical connection to four conductors 72 to 75.

The conductor 75 for example ensuring the return to ground, the conductors 72, 73, 74 are associated with three lamps 61, 62, 63; tracks 58, 59, 60 are arranged so that when track 12 feeds track 59, the lamp 62 lights up, as shown in FIG. 8, and indicates that the inflation pressure is correct, the lamp 62 may for example be green; when track 12 feeds track 58 or track 60, the lamp 61 or the lamp 63 lights up indicating respectively an over-inflated or under-inflated tire, the lamps 61 and 63 being for example of red color.

The needle 13 and the transmitter 14 can have multiple and varied applications.

Thus, according to the invention also, the information given by the needle 13 relating to the radial height of the tire 2 can be used for controlling the suspension of the motor vehicle, in the context of a so-called active suspension or intelligent; to refine the precision of the information, and / or the number thereof, several traces 8, offset axially and circumferentially, can be provided opposite the trace 7; these different traces are associated with as many tracks on the disc 20 of the transmitter and cylindrical portions on the roller of the transmitter; several needles can be provided, arranged circumferentially, for example four to ninety degrees from one another; the information on the hands of the four wheels, analyzed by a microprocessor, gives an image of the attitude of the vehicle at all times, important information for controlling the suspension, or even braking of the vehicle.

FIG. 9 shows a variant of implantations of needles allowing the measurement of the lateral deformation of the tire. Two needles 13 offset axially, along the axis of the wheel, are mounted in the rim 103B receiving the tire 102; the difference in length of the needles deployed gives a measure of the deformation of the tire along the axis of the wheel. The tread 39 being caused to move relative to the rim 3B, the end of the needle 13 can move relative to the band 39; therefore the end of the part 10 of the needle carries a shoe 1 1, of semi-spherical shape; as a variant, it also carries a ball crimped with play at the end of part 10: additional information can therefore be entered by reading the displacements in all directions of this ball on the strip 39, in the manner of the ball of a mouse controlling a microcomputer.

The fine and permanent measurement of the tire deformation allows the suspension to be controlled whatever the circumstances; we know, for example, that a motor vehicle, when driving, is subject to significant mass transfers, during turns, braking or acceleration, for example, but that also unevenness, or obstacles, on the road lead to variations in the attitude of the vehicle; of course, these manifestations should not be treated in the same way; the sensor according to the invention makes it possible to distinguish them; in fact, the vehicle being equipped on each wheel with a damping element of controlled length, the indication of the needle is used to vary the length of the damping element; when the needle indicates a crushing of the tire, the length of the shock absorber is reduced; if, following this decrease, the needle does not indicate a return to normal of the tire, then the length of the shock absorber is increased; when the needle indicates a reduction in the crushing of the tire of a wheel, the length of the shock absorber is increased; if, following this increase, the needle does not indicate a return to normal of the tire, then the length of the shock absorber of the opposite wheel is increased; we do not mean opposite wheel, either the wheel of the same axle or the wheel of another axle: this makes it possible to take into account the nature of the transfers (longitudinal or transverse), as they were read by the sensor according to the invention.

We will now describe, with reference to FIGS. 12 to 15, a variant of position sensor and information transmitter, in accordance with the present invention, in the application, for example, to indicating the state, overinflated or under-inflated, of a vehicle tire.

FIG. 12 shows, in partial section, a front wheel 3 of a motor vehicle; a tire 2, without an inner tube, is received with sealing by a rim 3B carried by a flange 3A fixed by screws, as known per se, to the web 18A of a hub 18 crossed by a wheel shaft 9 and carried by a pivot 26; the hub 18 is mounted for rotation on the pivot 26 by means of bearings 35; the web 18A of the hub 18 also carries a braking disc 4; a vehicle wheel is well known and will therefore not be described further. The rim 3B carries an inflation valve 200. The inflation valve 200 comprises a position sensor consisting of a needle 213 intended to give an indication representative of the relative position between, on the one hand, the rim 3B and, on the other hand, the inner face of the tread 242 of the tire 2, the needle 213 being located inside the tire 2 and carried by the valve 200.

The needle 213 of variable length consists of two cylindrical parts 205 and 210, the external part 210, relative to the axis of the wheel, being slidably mounted on the part 205. The internal part 205 is in the form of 'a sleeve of insulating material; on its outer face, it carries two conductive traces 207 and 208, extending longitudinally over a certain axial length of the part 205 and shown schematically in FIG. 13.

The part 210 of the needle 213, external with respect to the axis of the wheel, slidably mounted on the part 205, is also made of insulating material and carries on its periphery internally an annular conductive trace 212 shown diagrammatically in FIG. 2 ; the mounting is such that, depending on the relative axial position of the inner 205 and outer 210 parts, the traces 207 and 208 are brought into electrical relationship by the annular trace 212, or not.

Traces 207 and 208 are connected, when the valve 200 and the needle 213 are in place, to conductors 307 and 308 which, according to the invention, are part of an electrical circuit having its own power supply 400.

An information transmitter 414 is arranged between two parts, one of which is fixed and the other mobile; more specifically, the transmitter 414 consists of a transmitter 420, and a receiver 436 of signals, the transmitter 414 being a contactless transmitter; the transmitter 420 is linked to a movable part, rotating with the wheel 3, and the receiver 436 is integral with a fixed part of the vehicle and is arranged on a circle, centered on the axis of the wheel, the radius of which is equal to that of the circle on which the transmitter 420 is placed. In the example shown, the power supply 400 and the transmitter

420 are carried by a substantially flat plate 401 mounted on the hub 18 in the manner of the flange 3 A of the wheel 3, the plate 401 being clamped between the hub of the brake disc 4 and the flange 3A of the wheel 3 and held by the fixing studs of the wheel 3. At this Indeed, the plate 401 has a central opening 403 and peripheral openings 404 in a number equal to that of the fixing studs of the wheel 3 which pass through them.

In the example shown, the power supply 400 is fixed to the plate 401 on the inside, but it could also be fixed on the outside. At one of its ends, the plate 401 has its edge folded in

U defining a wing 402 parallel to the plane of the plate 401: the transmitter 420 is fixed on the outer face of the wing 402; when the plate 401 and the wheel 3 are mounted on the hub 18, it is arranged so that the wing 402 of the plate 401 is in line with the valve 200, a passage 405 in the plate 401 coinciding with a hole made in the flange 3A of the wheel 3; said hole and the passage 405 are crossed by the conductors 307 and 308 which are then connected, via a connector 241 carried by the valve 200, to the tracks 207 and 208 of the needle 213. A conductor 309 connects the supply 400 to the 'transmitter 420. The receiver 436 is carried by a fixed part of the vehicle; in the example shown in Figure 12, the receiver 436 is carried by the flange 4 A for protecting the brake disc 4. The receiver 436 is adapted to short-circuit two conductors 433, 434 when it receives a transmission from the transmitter 420; the two conductors 433, 434 form part of a power supply circuit for a control lamp 443 supplied by the vehicle battery, the lamp 443, preferably red, being placed on the dashboard of the vehicle.

The operation is as follows. The radius of the tire, and therefore the distance between the rim 3B and the inner face of the tread 242, being a very representative image of its inflation pressure, there is a permanent measurement of this distance and the triggering an indication when this distance reaches a critical threshold of under-inflation of the tire; to do this, the annular trace 212 of the part 210 of the needle 213 is positioned so that when it reaches, while rolling, the traces 207 and 208 of the part 205 of the needle, the total length of the needle corresponds to the alert distance; at this instant, thanks to the power supply 400, the transmitter 420 is excited and emits a beam which, when the transmitter 420 passes in front of the receiver 436, is received by the receiver 436 which lights the lamp 443 as explained above . It will be noted that, when driving, the receiver 436 picks up the beam emitted by the transmitter 420 only when the latter passes: thus, the lamp 443 flashes automatically, thus retaining the attention of the driver of the vehicle more strongly; the driver will only retain an uninterrupted flashing of the lamp 443: in fact, it is possible that the lamp 443 fleetingly lights up when, for example, the wheel 3 crosses an obstacle which deforms the tire to the point of causing the needle 213 the critical threshold; it will be understood that such a momentary crossing is not a sign of underinflation of the tire. As can easily be understood, the arrangement according to the invention facilitates the installation of the assembly on a vehicle which does not need to be fitted as standard, since such an assembly can in particular be mounted after the vehicle has been manufactured in series and its components marketed in the aftermarket. According to the variant of FIG. 14, the part 205 of the needle

213 internally carries a trace 207 opposite several traces, three in the example shown, 258, 259, 260; the transmitter 414 then comprises a transmitter 420 and a composite receiver 436, that is to say comprising several coupled cells having different transmission and reception characteristics, the transmitter 420 comprising three transmitting cells 420A, 420B, 420C coupled three receptor cells 436A, 436B, 436C respectively; these cells have been shown aligned in FIG. 3, but they can be distributed circumferentially, as shown in FIG. 15 with regard to the receiver 436 seen from the front in this figure. A conductor 475 ensuring for example the return to ground, the receiver cells are associated with conductors 472, 473, 474 supplying three lamps 461, 462, 463. The tracks 258, 259, 260 are arranged so that when track 212 supplies the transmitting cell 420B, this excites the receiving cell 436B which lights the lamp 462 which indicates that the inflation pressure is good; when runway 212 supplies the emitting cells 420A or 420C, these excite the receiving cells 436A or 436B which light the lamps 461 or 463 which indicate that the tire is respectively overinflated or underinflated. The power supply 400 can be a battery or an accumulator; advantageously, the accumulator is permanently charged by an external source; the external source is, for example, in a variant not shown, the solar radiation acting on a solar collector secured to the plate 401, on the face of the latter located on the external side, and placed in line with one of the openings that comprises the flange 3 A of the wheel 3, said solar collector being electrically connected to the supply 400 to charge the latter.

As is known, the needle 213 is continuously stressed during rolling during which the tire 2 deforms elastically radially to a certain extent, this deformation being reproduced in line with the needle 213, the telescopic parts 205 and 210 of which are move cyclically towards and away from each other; according to another variant not shown, this cyclic displacement is used to compress cyclically a piezoelectric quartz, disposed between the two parts 205 and 210 of the needle 213, each compression giving rise to an electric pulse delivered by the quartz which is sent, directly or via an amplifier, to the power supply 400 to charge the latter. Of course, the positioning of traces 212 and traces

207, 208 or 258, 259, 260 of the needle 213 must take account of the characteristics of the tire 2, and in particular of its dimensions, in particular its radial dimension. To avoid having to produce as many needles 213 as there are different tires, the invention provides the needle with numerous longitudinal traces, in any case in a number greater than the number of pieces of information transmitted by the transmitter. , i.e. points actually read, which number, in the examples above, corresponds to the number of transmitters 420 (or receivers 436, since these two numbers are equal), several traces, at least two , being electrically connected to the same transmitter 420. Adaptation to a given tire is obtained by cutting the conductors connecting to the transmitters which correspond to improper traces.

The following description, with reference to FIGS. 16 to 27, relates to another variant of position sensor and information transmitter.

In these figures, a wheel comprises a tire 502, without an inner tube, received by a rim 503 carried by a flange 504 fixed by screws to the web 505 of a hub 506 carried by a pivot 507 by means of bearings not represented. A needle 513 consists of a lever 508; the lever

508 is articulated, at its end 508A, on the rim 503; this articulation is produced by a U-shaped clevis 510, for example by welding, on the inner face of the rim 503 in its central zone, said clevis 510 bearing pads 511, 512 on each of its wings for an axis 514 ; a shim 515 of thickness is placed around the axis 514 between the lever 508, also crossed by the axis 514, and the bearing 51 1. The length of the lever 508 is such that when the end 508A is mounted on the axis 514, the end 508B of the lever 508, opposite the end 508 A, is brought into contact with the inner face of the tread of the tire 502; elastic biasing means permanently bias the lever 508 towards the position where this end 508B is in contact with this inner face of the tire; thus, the lever 508 extends in a plane perpendicular to the axis of the wheel while being inclined relative to the diametral plane of the wheel which passes through the axis 514 of articulation; advantageously, the inclination of the lever 508 is in the direction corresponding to the direction of rotation of the wheel when the vehicle is moving forward: in FIG. 16, it can thus be seen that, if the arrow F indicates this direction of rotation of the wheel, the lever 508, when the wheel is in the position of Figure 16, extends to the right of the figure, from top to bottom. Advantageously, as can be seen in FIG. 16, the lever 508 has a curved, circular shape allowing the lever 508, when it is folded down, against the action of the elastic biasing means, towards the rim 503, to conform to the form of the latter: in this position, the lever 508 is retracted at best, thus facilitating the mounting of the tire 502 on the rim 503, and its disassembly. We will easily understand that the angular position of the lever 508 relative to its articulation axis 514 depends, in addition to its length, which is fixed, also on the relative position of the internal face of the raceway of the tire 502 with respect to the rim 503, which depends in particular on the pressure prevailing inside the tire; it is therefore sufficient to detect the position of the lever 508 in the wheel to know, at all times, the behavior or the state of the tire 502.

According to the variant of FIGS. 16 to 25, this detection is obtained by means of a second lever 509 of which one end 509A is articulated on the lever 508 at a point close to the end 508B thereof which is in contact with the pneumatic 502; this articulation is produced by a pin 560 (FIG. 18) around which the two levers 508 and 509 can rotate. The other end 509B of the lever 509 cooperates with a detector designated as a whole by 516. As shown in FIG. 16, a tension spring disposed between the levers 508 and 509 constitutes the elastic means of biasing the needle 513 in contact with the tire.

The detector 516 comprises a body 517, in the shape of an arc of a circle and of U-shaped section, fixed inside the rim, in the manner of the clevis 510; inside the body 517, is arranged a support 518 made of insulating material, for example plastic; the support 518 is placed in the U formed by the body 517, between the wings of the U which have openings 519 (only one is shown in FIG. 20) in which take up pins 520 carried laterally by the support 518 mounted by clipping in the body 517 with which it is integral. The support 518, of rectangular section, comprises a housing 521 of rectangular section opening to the outside by a groove 522 of width less than that of the housing 521; the bottom 523 of the support 518 carries n conductive pads 524, only a pad referenced 524 _n being visible in FIG. 20; these pellets 524, for example 4 in number, are placed longitudinally relative to the bottom 523 and regularly spaced.

In the support 518, a shoe 525 is slidably mounted; the shoe 525 occupies in section the housing 521, including its groove 522 from which emerges an extension 526 of the shoe 525; skate 525 is crossed by a transverse passage 527 which is placed in such a way that, when the shoe 525 is mounted in the support 518, the passage 527 is in line with the row of pads 524; the passage 527 receives a conductive wiper 528, for example a carbon, subjected to the action of a spring 529 bearing on a metal cup 530; a conductive cover 532 fixed to the extension 526 of the shoe 525, for example by clipping, axially retains the cup 532 subjected to the action of the spring 529.

Offset transversely with respect to the pads 524 _n , a bar 534 is carried by the bottom 523 of the support 518, the bar 534 extending parallel to the line formed by the pads 524 _n : in a passage 537, a wiper 538 is subjected to the action of a spring 539 bearing on a cup 540 connected to a conductor 541 and retained by the conductive cover 532 which thus makes the electrical connection between the two wipers 528 and 538.

Each patch 524 _n is connected to a conductor 53 l _n and the conductors 53 l _{n as} well as the conductor 541 of the strip 534 are connected to a connector 561.

The connector 561 allows the electrical connection of the support 518 equipped with the pads 53 l _n and the strip 534 to a transmitter

550 pieces of information.

The transmitter 550 (Figures 22 to 25) comprises a fixed part and a mobile part. The movable part, that is to say the part which rotates with the wheel, is a disc 551 made of insulating material comprising circular metal tracks 554 _n in number equal to the number of pads 53 l _n , plus a track 555 corresponding to the bar 534, as will be explained below. Each of the tracks of the disc 551 is integral with a conductor, such as the conductor 553/3 of the track 554/3 shown in Figures 24 and 25; these conductors are welded to the tracks on the face facing the disc 551 and extend in radial grooves 556 of the disc 551, only two of which have been shown in FIG. 25, after having passed through an orifice provided in the wall of the disc 551 located at the right of said groove 556. The conductors 553 _n and the conductor of track 555 are connected to a connector, not shown, complementary to the connector 561 with which he cooperates; thus, due to this connection, the pads 524 _n are connected to tracks 554 _n and the bar 534 to track 555.

The fixed part of the transmitter 550 is a part 552 (FIGS. 22 and 23) made of insulating material secured to the pivot 507 carrying the wheel, and surrounding the axis of the latter; the part 552 has the general shape of a disc facing the moving part 551 and thus protecting the latter; the part 551 has a nut 557 in which are housed axial wipers, not shown, of the kind of those described in connection with the pad 525, each of these wipers rubbing on each of the tracks of the disc 551; these wipers are electrically connected to a connector 558, with 5 pins in the example described. This connector makes it possible to electrically connect each of the tracks of the disc 551 corresponding to the pellets to an indicator means placed in the passenger compartment of the vehicle, acoustic or visual, like the lamps of FIGS. 6 to 8, the track corresponding to the bar 534 being connected, via said connector, to a conductor making it possible to close the supply circuit of the indicating means, the detector 516 operating in this respect in the manner of a switch.

Such a position sensor variant works like the variants described above; the position of the lever 508, relative to its axis of rotation 514, varying as a function of the height of the tire 502 relative to the rim 503, this variation results in a displacement of the pad 525 in the support 518; when the wiper 528 is in line with a pad 531, the indicator means corresponding to this pad 531, therefore at a determined position of the lever 508 and, therefore, at a height of the tire relative to the rim, as a dashboard lamp is put into action.

Figures 26 and 27 show a variant detector which can be associated with lever 509; the detector 616 according to this variant comprises a body 617 similar to the body 517 of the previous variant but comprising laterally, in addition, two longitudinal returns 621; inside the body 617, is arranged an insulating support 618 having a longitudinal groove 626; on each side of the groove 626, are arranged, in the support 618, transmitter-receiver pairs 624-625, each pair constituting a fork sensor, with light barrier, such as that sold by HONEYWELL under the reference HOA 1873-013; the support

618 does not occupy the entire height of the body 617 and a carriage 619 is slidably mounted in the body 617 between the support 618 and the lateral returns 621 of the body 617, of the members 620, such as rollers, facilitating this sliding; the carriage 619 is coupled to the end 509B of the lever 509 while being articulated on the latter; the carriage 619 carries a tail 622 introduced into the groove 626, the tail 622 being intended to obscure or not, depending on the longitudinal position of the carriage

619 in the body 617, therefore from the position of the end 509B of the lever 509, the transverse space separating the transmitter and the receiver from a pair 624-625; there is thus a detector 626 without contacts.

According to the variant of FIGS. 28 to 30, the detection of the position of the lever-shaped needle 508 is carried out by an angular detection of the needle 508 around the axis 514. It suffices for this to place on the one of the wings of the journal 560 a sensor 700 sensitive to the action of a finger 701 carried by the lever 508: it is, for example, a sensor 700 of the Hall effect type sensitive to the action of a magnetic field created by a magnet 702 carried by the finger 701; such a sensor 700, supplied with current by a rubbing device, of the type described above, is advantageously with progressive action, that is to say capable of delivering information in the form of a gradually varying voltage, which is a function of the magnetic field delivered by the magnet, that is to say of the distance existing between said magnet 702 and said sensor 700. For exploitation of the electrical signal supplied by the sensor

700, this signal is amplified, as shown schematically in FIG. 29, by an amplifier 703 whose output is connected to the input of an analog-digital A / D converter 704 having, in the example shown, four outputs 705; the converter 704 classifies the output signal of the amplifier 703 in one of the four categories corresponding to the four outputs 705: by way of example, and assuming that the voltage level of the output signal of the amplifier 703 is between 2 and 10 volts, the four outputs 705 correspond to the following four categories: voltage between 2 and 4 volts, between 4 and 6 volts, between 6 and 8 volts, or between 8 and 10 volts. The electronics associated with the sensor 700, in particular the amplifier 703 and the converter 704 is housed in the hollow of the rim, in line with the lever 509.

Each output 705 of each category is respectively connected to a winding 706, carried for example by a disc of insulating material overmolding said windings 706 and integral with the rim of the vehicle wheel, or of the hub thereof; it will be readily understood that, as a function of the position of the needle 508, around the axis 514, it is the winding 706 corresponding to this range of position which will be excited. According to this variant, a transmitter is provided to give the user information indicating which of these windings is excited; for this, the transmitter comprises four transmission sensors integral with a fixed part of the vehicle surrounding the axis of the wheel each consisting of a module 707 with Hall effect sensitive to the magnetic field created by a coil 706 when it is excited. Preferably, the four windings 706 and the four modules 707 are regularly distributed around the axis of the wheel; this makes it possible to minimize the magnetic interference between the windings, as shown in FIG. 30. The information conducted on the dashboard by the four modules 707 is translated in clear by an electronic module which only translates information on the four successively, the initialization being carried out when the wheel is mounted on the vehicle, for example by the relative positioning of a power supply terminal of the wheel; it is indeed sufficient thanks to this initialization, that the windings 706 are opposite the modules which correspond to them (FIG. 30), as for the display, when the translation, or reading, is done for the user. The advantage of this variant with a single lever 508 lies in the fact that, on the one hand, it is very simple, and that, on the other hand, the lever can be reversibly mountable: thus, what whether the direction of mounting of the wheel on the vehicle, namely wheel to the right or wheel to the left, the lever 508 is inclined in the direction corresponding to the direction of rotation of the wheel when the vehicle is moving forward. According to a variant not shown, the axis of rotation 514 of the lever 508 is replaced by a ball joint, and the end 508B, of lever 508, in contact with the internal face of the tire raceway, moves on this face between two circumferential ribs provided on the internal surface of said tread; a position detector for the lever 508 detects not only the position of the lever 508 relative to the articulation in a plane perpendicular to the axis of the wheel but also its position relative to this plane; such an arrangement has the advantage of not only detecting the position of the tread relative to the rim, radially, but also its transverse offset relative to the latter, parallel to its axis: this makes it possible to control more complete and finer a suspension or control, for example, more securely the steering of a four-wheel steering vehicle.

Claims

1 - Relative position sensor of two rotating members of a motor vehicle, said rotating members being the rim (3B, 103B, 503) of a vehicle wheel and the tread (39) of the tire (2, 102, 502) associated with the wheel, the position sensor being partially carried by the rim (3B, 103B, 503) and partially contained inside the tire (2, 102, 502) which also contains an electrical supply intended for the sensor.

2 - Sensor according to claim 1, characterized in that it comprises a needle (13, 213, 513) disposed inside the wheel, a position detector (7, 8, 12 - 516 - 700, 702 ) to detect the position of the needle (13, 213, 513) inside the wheel, a transmitter being provided to transmit the information from the position detector (7, 8, 12 - 516 - 700, 702) to a fixed, non-rotating part of the vehicle, said information being representative of the deformation of the tire (2, 102, 502) relative to the rim (3B, 103B, 503).

3 - Sensor according to claim 2, characterized in that the needle (13) consists of at least two cylindrical parts (5, 10) slidably mounted one inside the other, of electrically insulating material, at least two conductive traces (7, 8) extending longitudinally and electrically connected to an electrical circuit for use of the sensor, and a conductive trace (12), located opposite the two said longitudinal traces (7, 8) and adapted to come in contact with the longitudinal traces (7, 8) when one of the two parts (5, 10) moves inside the other, each of the two parts (5, 10) being linked at least by contact to each said organs whose relative position is to be measured.

4 - Sensor according to claim 3, characterized in that the two conductive traces (7, 8) longitudinal are carried by the surface of one (5) of the parts, and the trace (12) opposite is annular and carried by the other (10) part on its face located opposite the longitudinal traces (7, 8).

5 - Sensor according to one of claims 3 or 4, characterized in that the longitudinal traces (7, 8) are carried by the outer face of a part (5) which slides in the other part (10). 6 - Sensor according to claim 5, characterized in that each of the longitudinal conductive traces crosses the wall of the part (5) which carries it and is connected to a connection pin (15A, 16A), a plug (40), made of insulating material, carrying the pins (15A, 16A) which are connected to conductors (15B, 16B) passing through the plug (40) and folded over the outer surface of the plug (40), the plug (40) being press fitted in the part (5) with longitudinal traces (7, 8) which are, in this position of the plug (40), in contact with the conductors (15B, 16B). 7 - Sensor according to one of claims 3 to 6, characterized in that the annular conductive trace (12) is adapted to come into contact with the longitudinal traces (7, 8) by means of balls trapped in the part ( 10) bearing the annular trace (12).

8 - Sensor according to one of claims 3 to 7, characterized in that one of the two members carries two pins

(15, 16) metallic complementary to the pins (15A, 16A) of the needle (13).

9 - Sensor according to claim 7, characterized in that the longitudinal traces (7, 8) are provided on longitudinal grooves in which the balls slide.

10 - Sensor according to one of claims 3 to 9, characterized in that the two parts (5, 10) are slidably sealed and define a sealed chamber in which a pressurized fluid biases them in extension. 11 - Sensor according to one of claims 3 to 10, characterized in that the annular (12) and longitudinal (7, 8) traces being in contact, they close an electrical circuit in which an electric current flows.

12 - Sensor according to one of claims 3 to 11, characterized in that the annular (12) and longitudinal (7,

8) are arranged to behave like a potentiometer in their relative longitudinal movement.

13 - Sensor according to one of claims 10 to 12, characterized in that the connection of the needle (13) to one of the two members is achieved by an elastic bellows membrane (49) of which one end is integral a part (5) of the needle (13), said membrane (49) being housed in a cylindrical housing (86) of said member, and having at rest a position of minimum length towards which it is recalled by its own elasticity, said housing (86) being of sufficient length to receive the membrane (49) in the rest position and the needle (13) in the retracted position, the inner chamber of the membrane being in communication with the inner sealed chamber of the needle (13), so that when the inside of the needle (13) is subjected to the action of the pressurized fluid, the membrane (49) is expanded in the housing (86) and the needle (13) is in extension and out of the housing (86).

14 - Sensor according to one of claims 1 to 3, characterized in that it is at least partially integrated (213) in the inflation valve (200) of the tire.

15 - Sensor according to claim 2, characterized in that the needle (513) consists of a lever (508) articulated on the rim

(503) at one of its ends (508 A), the other end (508B) of the lever (508) is in contact with the inner face of the tire tread (502) against which it is resiliently biased.

16 - Sensor according to claim 15, characterized in that the detection of the position of the needle (513) is carried out by a second lever (509) articulated on the lever (508) which cooperates with a detector (516).

17 - Sensor according to claim 16, characterized in that the detector (516) comprises a support (518) insulating integral with the rim and whose bottom (523) carries pads (524) conductive and a bar (534) conductive , a shoe (525) being slidably mounted in the support (518) and carrying a wiper (528) adapted to cooperate with each of the pads (524) and a wiper (538) cooperating permanently with the bar (534), the two wipers (528, 538) being electrically connected.

18 - Sensor according to one of claims 15 to 17, characterized in that the transmitter (550) comprises a fixed part (552) and a movable part (551); the mobile part (551) is an insulating disc comprising circular metal tracks (554) in a number equal to the number of pads (531) plus a track (555), the tracks (554, 555) being integral with a conductor, these conductors being connected to a connector for connection to the pellets (524) and to the bar (534).

19 - Sensor according to claim 18, characterized in that the fixed part of the transmitter (550) is an insulating part (552) carrying a nut (557) in which are housed friction shoes cooperating with the tracks (554, 555) of the disc (551).

20 - Sensor according to claim 19, characterized in that the fixed part carries a connector for connecting the tracks (554, 555) of the disc (551) to an indicator means available to the user inside the vehicle .

21 - Sensor according to claim 16, characterized in that the detector (616) comprises a support (618) having a longitudinal groove (626) on each side of which are arranged transmitter-receiver pairs (624-625) of a light barrier fork sensor, a carriage (619), coupled to the second lever (509) being slidably mounted relative to the support (618) and carrying a tail (622) sliding in the groove (626) and capable of obscuring , or not, the transverse space separating the transmitter and the receiver from a pair (624-625). 22 - Sensor according to one of claims 1 to 14, characterized in that an electrical supply (400) of the electrical circuit is integral in rotation with one (3B) of the two rotating members, the transmitter (414) being of the contactless type and consisting of two parts, one of which (420) is integral with said rotating member (3B) and the other (436) of the support (4A).

23 - Sensor according to claim 22, characterized in that the electrical supply (400) is a chargeable accumulator.

24 - Sensor according to claim 23, characterized in that the power supply (400) is charged by a solar collector secured to one (3B) of the two rotating members.

25 - A sensor according to claim 23, characterized in that the supply (400) is charged by a piezoelectric quartz put in compression by the relative movement of the two parts (205, 210) of the needle (213). 26 - Sensor according to one of claims 1 to 14, wherein the transmitter (14) comprises an annular disc (20) insulating integral in rotation with the rotating member, centered on the axis of said rotating member, and carrying on one of its faces at least two concentric circular tracks (21, 22) electrically conductive, each connected to an electrical conductor (23, 24) carried by the disc (20) and connected to a connection means (41) to be connected to an electric cable (17) having at least two conductors, the transmitter (14) further comprising at least one roller (36) of insulating material, cylindrical and of circular section, said roller (36) having at least two metal inserts (29, 29A; 30, 30A) projecting, on the one hand, relative to a front face (42) of said roller ( 36), to cooperate in electrical contact with the tracks (21, 22) of the disc (20), and, on the other hand, relative to the cylindrical outer surface of the roller (36), to cooperate in electrical contact with grooves annulars coated with a conductive material (50, 51) provided on the surface of a path inner bearing (27) of insulating material, carried by the support (26) and on which the roller (36) rolls, means (44, 45) being provided for driving the roller (36) by the disc (20 ).

27 - Sensor according to claim 26, characterized in that the needle (13) is electrically connected, by a connection which passes through the rim of the wheel (3), to the disc (20) of the transmitter (14) which transmits a information representative of the deformation of the tire (2) relative to the rim (3B).

28 - Sensor according to one of claims 10 or 13, characterized in that the fluid is the compressed air prevailing in the tire.

29 - Sensor according to claim 15, characterized in that the detection of the position of the needle (513) is carried out by a sensor (700) detecting the angular position of the needle (513) around its articulation (514 ). 30 - Sensor according to claim 29, characterized in that the sensor (700) is sensitive to the action of a finger (701) carried by the lever (508).

31 - Sensor according to claim 29, characterized in that the sensor (700) is of the Hall effect type sensitive to the action of a magnetic field created by a magnet (702) integral with the needle

(513). 32 - Sensor according to claims 30 and 31, characterized in that the magnet (702) is carried by the finger (701).

33 - Sensor according to one of claims 29 to 32, characterized in that the signal supplied by the sensor (700) is amplified by an amplifier (703).

34 - Sensor according to claim 33, characterized in that the output of the amplifier (703) is connected to the input of an analog-digital converter (704).

35 - Sensor according to claim 34, characterized in that the converter (704) has outputs corresponding to categories in which it classifies the output signal of the amplifier (703).

36 - Sensor according to claim 35, characterized in that each output of the converter (704) corresponding to each category is connected to a coil (706) integral with the rim of the wheel.

37 - Sensor according to claim 36, characterized in that a transmitter comprises as many transmission sensors (707) as there are categories.

38 - Sensor according to claim 37, characterized in that each transmission sensor (707) is an effect module

Lobby.

39 - Sensor according to claim 38, characterized in that the information conducted on the dashboard is translated by an electronic module which only translates information on all the information during a wheel revolution.

40 - Sensor according to claim 15, characterized in that the articulation of the lever (508) is a ball joint.

41 - Sensor according to claim 40, characterized in that the end of the lever (508) in contact with the internal face of the raceway moves on this face between two circumferential ribs provided on the internal surface of said tread .

42 - Sensor according to one of claims 40 or 41, characterized in that a position detector for the lever (508) not only detects the position of the lever (508) relative to the articulation in a plane perpendicular to the axis of the wheel but also its position relative to this plane.

43 - Use of the sensor according to one of claims 1 to 42, characterized in that the information transmitted by the transmitter (14) is used to deliver to the driver of the vehicle information representative of the pressure prevailing inside the pneumatic (2).

44 - Use of the sensor according to one of claims 1 to 42, wherein the information transmitted by the transmitter (14) is used to modulate the braking of the wheel.

45 - Use of the sensor according to one of claims 1 to 42, in which the information transmitted by the transmitter (14) is used for controlling the suspension of the vehicle.

46 - Use of the sensor according to claim 45, in which several needles (13) are provided distributed circumferentially around the axis of the rim of the wheel (3).

47 - Use of the sensor according to one of claims 1 to 42, in which at least two needles (13) are axially offset along the axis of the wheel. 48 - Use of the sensor according to one of claims 1 to 42, the vehicle being equipped on each wheel with a damper element with controlled length, in which the indication of the needle (13) is used to vary the length of the damping element.