US3042146A - Lubrication of a marine propulsion device - Google Patents

Description

July 3, 1962 W. J. SHIMANCKAS LUBRICATION OF' A MARINE PROPULSION DEVICE Filed Nov. 2l, 1960 M4, mslm 3,042,146 LUBRICATION F A MARINE PROPULSIUN DEVICE William .'l. Shimanclras, Waukegan, lll., assigner to Outboard Marine Corporation, Waukegan, Ill., a corporation of Delaware Filed Nov. 21, 1960, Ser. No. 76,773 l0 Claims. (Cl. 184--6) This invention relates to lubrication of a marine propulsion device. The invention has particular application to lubrication of the drive gears of an outboard motor or an inboard-outboard driving arrangement.

There are advantages in using the submersible housing parts of a marine propulsion device for the storage of oil required for lubrication. In the first place, considerable storage space is available and in the second place the oil thus stored is cooled by release of its heat to the water in which the device operates.

However, it is found that if gearing which transmits motion from the drive shaft to the propeller shaft is required to operate fully submerged in oil, there is a very considerable loss of power. The meshing gear teeth compress and circulate the oil within the housing. A substantial part of the available power may be consumed in this manner without contributing to the propulsive effort.

All of the advantages of oil storage in the lower unit can be retained, and the power loss is greatly reduced, by withdrawing from the gear casing all of the oil not actually required for the lubrication of the gears, such oil being maintained in circulation during the operation of the device by the provision of an elevated oil-receiving chamber which has restricted communication with the gear case through a metering orice having a capacity less than that of the withdrawal pump. Thus, shortly after the device is put into operation, the excess pump capacity will remove all excess oil from the gear case and will continue to remove the oil which is constantly in circulation, trickling back into the gear case.

Obviously, the circulating oil can be used for lubricating other portions of the marine propulsion device and this is exemplified in an in-board-outboard organization in which there are gears at an upper level to which the oil is supplied before it passes to the elevated storage chamber from which it trickles back to the submerged gear case in the course of its recirculation.

In the drawings:

FIG. l is a fragmentary detail view in longitudinal vertical section through a portion of the lower unit of an outboard motor embodying the invention.

FIG. 2 is a similar view on a reduced scale diagrammatically showing in longitudinal vertical section a portion of the vertical strut of an inboard-outboard organization embodying the invention.

In the shaft housing or vertical strut portion 5 of the lower unit of an outboard motor as fragmentanily illustrated in FlG. l, there is unitarily included a gear case chamber 6 in which the propeller shaft 7 is provided with bearings at 8 and 9 for the driving of propeller 10.

A vertical drive shaft i1 powered by an engine (not shown) is piloted in the hub 12 of the driving pinion 13 which meshes with gears 14 and 15. These gears are free on the propeller shaft 7 except as coupled thereto by the shiftable clutch collar 16, which may be moved through the neutral position illustrated into engagement with either gear 14 or l5 by means of a shipping lever 17 actuated by rod 18.

A partit-ion 19 separates the gear case portion 6 of the apparatus from an elevated oil reservoir at 20. In the generic aspect of the invention, and looking only at the problem of removing the oil from the gear case, the

- smarte ig@ Patented July 3s 1962 reservoir 20 might be separate and at any convenient location. There are, however, advantages in placing it in the lower unit as shown. In any event, limited communication permitting the oil to trickle back into the gear case is provided. In the preferred embodiment, this is accomplished in a metering oriiice 2.1 in partition 19. When the parts are at rest, the oil will stand approximately at the level indicated at 22 in FIG. 1.

When the drive shaft 11 is in operation, both the gears 14 and 1S are continuously actuated. Under these conditions, the cam 23 on the hub of driven gear 14 engages a cam follower 24 on the pump plunger 25 to displace the plunger downwardly against the bias of spring 26. The oil received into the cylinder 27 through the intake port 28 will be forced by downward movement of the pump plunger 25 to pass through the port 2S into the reservoir Ztl, ultimately iilling such reservoir to the level illustratively suggested at Sti. The location of the pump intake port 28 will determine the level 31 at which oil will be maintained in gear case 6, the desired arrangement being such that the peripheries of the gears 14 and l5 dip into the oil without undue displacement thereof.

No valve is necessary because the resistance of the duct 2.9 is sudiciently high so that there is little backward flow of the oil in the upstroke of the plunger 25 under bias of spring 26. Any partial vacuum created in the cylinder Z7 is relieved when the piston clears the intake port 2S. The positive pressure of the plunger in response to the action of cam 25 is suiiicient to force the oil through duct 29 notwithstanding the flow resistance offered by the duct.

Even at the elevated level 30 4to which the oil is raised in the reservoir 2liduring pump operation, most or all of the oil is below water level, the water level being apu proximately the same as the oil level 30 during normal use of the device. Thus all of the recirculating oil is cooled. However, even if the water level were materially lower than contemplated, the oil would still be cooled by circulating through the gear housing, there being a constant trickle of oil owing by gravity from the chamber 20 to the gear housing through the metering orifice 2l, which regulates the rate of such flow to an amount which is less Vthan the oil displaced by the pump 2S. Because of the difference `between the amount of oil pumped and that returning through the metering orifice, the oil in the gear housing 6 is kept at the minimum level required for lubrication of the gears.

Pressure is desirably equalized or at least balanced between the gear housing and the oil storage chamber 20. This may conveniently be done by providing a port at 32 above oil level in the reservoir 20, the port opening into the passage 33 in which the rod 18 is disposed. Since this passage is in open communication with the gear case 6, there will be no back pressure which could preclude movement of the oil in either direction.

In actual practice some sort of water pumping arrangement will be used to cool the ,engine (not shown) which powers the drive shaft 11. A variety of Water pumps are known to the art and since the water pump forms no part of the present invention, it is not illustrated in FIG. l. However, one optional arrangement for pumping water is illustrated incidentally in FIG. 2 and a similar structure may be used in the youtboard motor or propulsion unit device pictured in FIG. l.

The organization shown in FIG, 2 comprises a Vertical strut portion of an inboard-outboard marine propulsion device. The strut portion Si)l is tiltably mounted on means not shown to pivot about a transverse horizontal -axis designated at 34. This axis is on the pitch circle of a pair of gearlike coupling elements 35, 36 which function as a universal joint to accommodate pivotal movement of the strut 50 while maintaining driving connection 'oetween the power shaft 37 and the extension shaft 38 which mounts the gear 39. This gear meshes within the gear 40 at the upper end of the vertical drive shaft 11) which corresponds to the vertical drive shaft 11 in the FIG. l embodiment. The housing 45 comprises a gear case chamber which encloses the gears 39 and 40 to retain lubricant therefor. The lubricant is maintained at a level indicated at 46 by the overflow duct 47 which communicates through a hose 48 with another duct 49 leading to the lubricant storage chamber 200. From the reservoir Zilli), the oil trickles through a metering oriiice 21() into the gear casing 6d in which the pinion 130 and the driven gears i4!) and 150 are disposed. In the diagrammatic showing, the reversing clutch is omitted but it will be understood that an arrangement similar to that of FIG. 1 will ordinarily be employed to couple the gears 140 and 150 selectively to the shaft 70 upon which propeller 100 is mounted.

The cam 30, which is here shown on the hub of gear 150, drives the pump plunger 256 to pump oil from the gear casing when the parts are in operation. The pump cylinder 270` has its inlet at 286 and contains a spring 260 which biases the pump plunger 250 upwardly.

Oil displaced by the pump plunger d is discharged through the duct 2d. An annular groove 52` extends around the propeller shaft bearing Sti and communicates with ducts 53, S4, 55 leading to the -top of the strut and discharging at 56 into the upper gear case 45. The level of the overiiow duct 47 will determine Athe level of oil maintained in this gear case for the lubrication of the gears 39 and 4G, as the overow is returned through duct 49 to the reservoir 200;

Thus, `circulation is maintained throughout both gear cases and the reservoir without maintaining in either gear case during operation an oil level higher than is required for actual lubrication of the gears.

In this embodiment, pressures in the several chambers may conveniently be balanced by `making the shaft 110 tubular. The internal shaft duct 111 opens through gear di) into the upper gear case 45 and through gear 130 into the lower gear case 60. A drilled hole at 112 places duct M1 in communication with reservoir 200. In this embodiment, the duct 111 communicates with air space above operating oil levels in all three chambers to equalize pressures throughout during operation and to balance pressures when the lower gear case is full of oil with the parts at rest.

With the parts at rest, much of the oil in the reservoir will flow through the metering orifice 210 into the lower gear case, but as soon as drive shaft 110 is in motion, the surplus oil will be pumped from the lower gear case to the upper gear case and thence will iiow to the reservoir to maintain the oil in the reservoir at `the elevated level shown.

I claim:

1. In a mar-ine propulsion device having a submersible gear case and an oil storage reservoir at a higher level and power-operated gears and shafts in said gear case, means for pumping from said gear case to said reservoir surplus oil beyond that required for the lubrication of said gearing, said pumping means Ihaving an oil inlet so located as to define a working level of oil in said gear case well Abelow the top thereof, means for driving the pumping means from one of said shafts whenever the shafts and gearing are in operation, and means providing a restricted metering communication between the reservoir and gear case having flow capacity less than that of said pumping means for the gravity iiow of oil from the reservoir to the gear case at a rate less than the rate at which the pumping means removes oil from the gear casing, whereby to maintain continued circulation of oil between the reservoir and the gear casing during shaft-and gear operation while keeping surplus oil drained from the gear casing.

2. The device of claim 1 in which the propulsion device comprises an upright strut member having a generally upright drive shaft and a generally horizontal propeller shaft, the gearing including gears on the drive shaft and propeller shaft in mesh for providing connection between said shafts, the oil level being materially below the level at which said gears mesh, and said gear casing and the strut member having an interior partition subdividing it to separate said gear casing from a cavity above the casing constituting said reservoir, said partition having an opening constituting said metering orifice, and a separate means communicating with the reservoir and the gear case for balancing pressures there- 1n.

3. In a marine propulsion device having a submersible gear case and an oil storage reservoir at a higher level and power-operated gears and shafts in said gear case, means for pumping from said gear case to said reservoir surplus oil beyond that required for the lubrication of said gearing, said pumping means having an oil inlet so located as to define ya working level of oil 4in said gear case, means for driving the pumping means from one of said shafts whenever the shafts and gearing are in operation, and means providing a restricted metering communication between the reservoir and gear case having flow capacity less than that of said pumping means for the gravity flow of oil from the reservoir to the gear case at a rate less than the rate at which the pumping means removes oil from the gear casing, whereby to maintain continued circulation of oil between the reservoir and the gear casing during shaft and gear operation While keeping surplus oil drained from the gear casing, the propulsion unit comprising an upper gear case having Agearing therein requiring lubrication, said pumping means having a discharge connection leading to said upper gear case and said upper gear case having an over-ow port leading `to said reservoir for the storage in the reservoir of oil pumped from the rst mentioned gear case to t-he upper gear case during the operation of the gears and shafts in the lower gear case, such oil Abeing in continuous circulation during such operation, while being maintained during operation at a level in the lower gear case which is materially below the top of said lower gear case.

4. The device of claim 3 in which duct means is provided for placing both gear casings and the reservoir in communication independently of pump and port.

5. The device of claim 3 in which one of said shafts extends from the upper gear case to the gear case rst mentioned, the shaft being tubular and having an internal duct communicating with both gear cases and a lateral port opening into the reservoir and providing pressure balancing communications between the gear cases and reservoir.

6. In a marine propulsion unit, a strut element interiorly provided with an oil storage reservoir and having at its lower end a submersible gear case, a propeller shaft and at least one continuously dri-ven gear in said gear case, a drive shaft extending through said strut and provided with a pinion meshing vwith said gear, a pump having an oil pumping part operatively provided with means for driving it from one of said shafts, said pump comprising a chamber having an inlet opening from said gear case at a level below the level of mesh of said pinion and said gear and determinative of a desirable level of oil in said gear case well below the top thereof, means providing a pump discharge conduit leading from said pump to a level above the -gear case and having a discharge connection to said reservoir, said reservoir having a metering port providing gravity communication between the reservoir and gear case, said port having an oil ilow capacity less than the pump-produced capacity of said conduit.

7. In a marine propulsion unit, a strut element interiorly provided with an oil storage reservoir and having at its lower end a submersible gear case, a propeller shaft and at least one continuously driven gear in said gear case, a drive shaft extending through said strut and provided with a pinion meshing -with said gear, a pump having an oil pumping part operatively provided with means for driving it from one of said shafts, said pump comprising a chamber having an inlet from said gear case at a level determinative of a desirable level of oil in said gear case, means providing a pump discharge conduit leading from said pump to a level above the gear case and having a discharge connection to said reservoir, said reservoir having a metering port providing gravity communication between the reservoir and gear case, said port having an oil flow capacity less than the pump-produced capacity of said conduit, the pump inlet port being disposed at a level intersected by a lower peripheral part of said gear, the pump comprising a displacement plunger having an upward biasing spring, and having a cam follower, said gear having a cam-shaped hub portion acting on the follower opposite to the action of said spring on the follower to displace the plunger in opposition to said spring.

8. A marine propulsion device comprising a generally upright housing with partition means defining a gear case near Ithe bottom of the housing, a reservoir at an intermediate level in the housing, and an upper gear case near the upper end of the housing; conduit means extending from the upper gear case to the reservoir; the partition means being provided with a metering port between the reservoir and the first mentioned gear case at the lower end of the housing; a drive shaft having portions in both gear cases; a propeller shaft in the gear case at the lower end of the housing; said drive shaft and propeller shaft having meshing gears; a power shaft; meshing gears on the power shaft and the drive shaft and disposed in the gear case at the upper end of the housing; a pump means having an inlet from the gear case at the lower end of the housing at a level approximating the lower peripheral portions of said propeller shaft gear, said pump means having an oil displacement capacity in excess of the gravity flow capacity of the port and having connections for delivering oil from said inlet to the gear case at the upper end of the housing, said last mentioned gear case having an overflow duct at a level just adequate for the lubrication of the gears therein and leading via the conduit means to said reservo1r.

9. In a marine 4propulsion device having a propulsion unit which is submerged during normal operation and which contains a propeller shaft, a gear thereon, a driving gear meshing with the propeller shaft gear at a level above the propeller shaft, and a gear case in which said gears are conned, the combination therewith of means for powering the driving gear and including parts remote from said gear case and requiring lubrication, means within said propulsion unit providing an oil reservoir, said means including a partition having a metering port connection for gravity lW of oil from the reservoir to the gear case aforesaid, and pump means having an oil capacity in excess of the capacity of the metering port and provided with an inlet below the propeller shaft in the lower portion of the gear case aforesaid and having discharge conduit means leading to said remote means requiring lubrication, said conduit means extending thence to said reservoir, whereby said pump means maintains constant circulation of oil through said submersible gear case and said remote parts requiring lubrication and said reservoir While maintaining the submersible gear case substantially free of oil in excess of that required for lubrication of the gears therein.

l0. The device of claim 9 in further combination with means for balancing pressures to which the circulating oil is subject.

References Cited in the file of this patent UNITED STATES PATENTS

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