Lubricated engine compensator assembly and motorcycle having the same

The present invention provides a compensator assembly for use in a motorcycle. The compensator assembly includes an input member, and an output member driven by the input member through a torque-buffering interface. The compensator assembly also includes one or more lubrication passageways formed therein extending between a distal end and one or more interfaces to provide lubricant thereto.

FIELD OF THE INVENTION

The present invention relates to a lubricated compensator assembly for use on a motorcycle to dampen impulses in the drivetrain.

BACKGROUND OF THE INVENTION

Motorcycles typically include a compensator assembly within the drivetrain to dampen the impulse loads between the engine and the rear wheels. The impulse loads can be the result of natural engine torque spikes or abrupt road forces applied to the rear wheel. Some such compensator assemblies are mounted on the crankshaft of the engine and transmit torque to a clutch at a transmission input via a drive chain, gear set, belt, and the like. As such, the compensator assembly generally includes various moving parts that can, over time, wear and break down.

To limit the wear and tear on the compensator assembly, some designs utilize the pressurized oil or lubricant provided by the engine lubrication system. Other compensator designs rely on splash lubrication within the primary cover of the motorcycle. Still other compensator designs are not lubricated at all.

SUMMARY OF THE INVENTION

In some embodiments, the present invention provides a motorcycle having a frame, a rear wheel rotatably coupled to the frame, an engine supported by the frame and configured to drive the rear wheel the engine having a crankshaft, and a compensator assembly coupled between the crankshaft and the rear wheel to dampen impulse loads between the crankshaft and the rear wheel. The compensator assembly has a shaft extension rotatably fixed with respect to the crankshaft, an input member rotatably fixed and axially slideable with respect to the shaft extension forming a first interface therebetween, an output member driven by the input member with a torque-buffering interface, a retainer rotatably fixed to the crankshaft and configured to axially retain the input member and the output member thereto. The retainer and output member are rotatably coupled to one another forming a second interface therebetween. The retainer includes a passageway extending between a distal end of the retainer and at least one of the first interface and the second interface.

In another embodiment, the present invention provides a compensator assembly for transmitting torque along a drivetrain having at least one shaft therein. The compensator assembly having an input member rotationally fixed to and axially moveable with respect to the shaft along a first interface, an output member driven by the input member with a torque-buffering interface, and a retainer mounted to the crankshaft and configured to retain the input member and output member thereto. The retainer and output member being rotatably coupled to one another to form a second interface therebetween, and where the retainer defines at least one passageway extending between a distal end of the retainer and at least one of the first interface and the second interface.

In still another embodiment, the present invention provides a motorcycle having a frame, a rear wheel rotatably coupled to the frame, an engine supported by the frame and configured to drive the rear wheel, the engine having a crankshaft defining a crankshaft axis, and a compensator assembly to dampen impulse loads between the crankshaft and the rear wheel. The compensator assembly includes a shaft extension rotatably fixed with respect to the crankshaft, an input member rotatably fixed and axially slideable with respect to the shaft extension to form a first interface therebetween, an output member driven by the input member with a torque-buffering interface, and a retainer rotatably fixed to the crankshaft. The retainer and input member being rotatably coupled to one another forming a second interface therebetween. Where the distal end of the retainer defines a pocket, and where the retainer includes a passageway extending and in fluid communication with the pocket and at least one of the first interface and the second interface. The compensator assembly also includes a retention bolt coupling the retainer to the crankshaft, the retention bolt having a head portion with a substantially conical outer surface, and where at least a portion of the conical outer surface is positioned within the pocket. The motorcycle also has a cover at least partially encompassing the compensator assembly therein, the cover having a plurality of ribs forming an apex that is vertically aligned with the crankshaft axis.

DETAILED DESCRIPTION

FIG. 1illustrates a motorcycle30including a drive assembly34. The motorcycle30includes a frame38, a steering assembly42pivotally coupled to a forward portion of the frame38, and a front wheel46rotatably coupled to the steering assembly42. The frame38also includes a swingarm portion50moveable with respect to the remainder of the frame38. A rear wheel54is rotatably coupled to the swingarm50. An engine56(e.g., a V-twin internal combustion engine) of the drive assembly34provides power and torque to drive the rear wheel54through a drivetrain including a primary drive, a clutched transmission, and a final drive as discussed in further detail below. Although illustrated with two wheels, in alternate constructions the motorcycle may include a three wheel design.

The engine56includes a crankcase58(FIG. 1), which supports a crankshaft62and a flywheel66for rotation about a crankshaft axis70(FIG. 2). The crankshaft62extends outwardly from the crankcase58to form a distal end74having one or more spline teeth78thereon. When assembled, the crankshaft62is supported for rotation relative to the crankcase by one or more bearings60. A spacer82abuts the bearing60and positions a compensator assembly86proximate the distal end74of the crankshaft62. Although not shown, the engine56also includes a lubrication system providing lubricant or oil to various elements within the engine. More specifically, the engine lubrication system draws oil from within the crankcase58and pumps it, under pressure, to various locations throughout the engine56.

The drive assembly34also includes a primary cover90(FIGS. 1-3) coupled to the crankcase58of the engine56to define a primary chamber94therebetween. The primary chamber94at least partially encloses the compensator assembly86and a quantity of oil, separate from the oil of the engine lubrication system. The primary cover90typically forms a seal with the crankcase58to prevent the oil from leaking. The primary cover90may also be removed to allow access to the primary chamber94for maintenance and the like.

The primary cover90also includes a pair of vanes or ribs98(FIG. 3) extending into the chamber94to form a “V” shape. When assembled, the apex102of the ribs98(e.g., the point of the “V”) is positioned slightly above and vertically aligned with the crankshaft axis70. During use, the ribs98collect a quantity of the splash oil within the chamber94and funnel it towards the apex102which in turn directs the oil onto the retaining bolt106of the compensator assembly86(described below). The shape and positioning of the ribs98are configured to maximize the volume of oil directed onto the compensator assembly86.

Illustrated inFIGS. 2-12, the compensator assembly86is configured to dampen impulse loads within the drivetrain of the motorcycle. More specifically, the compensator assembly86is coupled for rotation with the crankshaft62and operates to dampen impulse loads between the engine56and the rear wheel54. The compensator assembly86includes an output member or sprocket110, an input member or cam slider114, a shaft extension118, and a retention assembly122. In addition to transmitting torque, the compensator assembly86of the present invention is designed to provide oil to various interfaces within the device independent the lubrication system of the engine56. Stated differently, the compensator assembly86collects oil from within the primary cover90(e.g., via the ribs98) and directs it by way of oil passageways to one or more interfaces within the compensator assembly86. In the present description, an interface is defined as any area of the compensator where two or more surfaces slide with respect to one another.

The shaft extension118of the compensator assembly86is coupled to the distal end74of the crankshaft62to rotate therewith. As shown inFIGS. 2 and 4, the shaft extension118includes an internal spline having one or more spline teeth126that engage the external spline teeth78of the crankshaft62. The shaft extension118also includes an external spline having one or more spline teeth130that are configured to support the cam slider114. More specifically, when assembled the exterior spline teeth130of the shaft extension118cause the cam slider114and the shaft extension118to rotate synchronously while allowing the cam slider114to move axially along the length of the shaft extension118. During operation, the shaft extension114and the cam slider114rotate synchronously with the crankshaft62.

The shaft extension118also includes an oil groove134formed proximate the first end138and at least partially defined by a lip142extending axially therefrom to form a pocket146. The oil groove134is open on the radially inward side and extends along the periphery of the shaft extension118(FIG. 5). During use, the oil groove134collects oil and directs it between the external spline teeth130to lubricate the mutually sliding surfaces (e.g., interface) of the cam slider114and the shaft extension118.

In the illustrated construction, the oil groove134is formed by cutting (e.g., boring) into the lip142in a radially outward direction to produce an outer groove diameter UDgreater than the root diameter RDof the external spline teeth130(FIG. 5). As such, the oil groove134“breaks through” between each external spline tooth130forming an opening150for oil to pass. In the illustrated construction, the roots between each spline tooth130are cut deeper than normal to aid in producing the opening150and to facilitate oil distribution between the sliding surfaces, or interface, between the shaft extension118and the cam slider114.

Illustrated inFIG. 6, the cam slider114of the compensator assembly86is substantially annular in shape, forming internal spline teeth154configured to engage the exterior spline teeth130of the shaft extension118to form an interface therebetween. When assembled, the cam slider114is fixed for rotation with and axially moves along the shaft extension118in response to impulse loads in the drivetrain. More specifically, the cam slider114is biased by one or more biasing members or springs152towards the distal end74of the crankshaft62and into engagement with the sprocket110.

The cam slider114also includes a cam surface158extending axially from a base surface162to produce varying heights along the circumference of the cam slider114(FIG. 6). When assembled, the cam surface158of the cam slider114engages the sprocket110to transmit torque therebetween. In the illustrated construction, the cam slider114includes three substantially similar cam elements166, each corresponding to and in contact with a respective one of the spokes170of the sprocket110(described below). In alternate constructions, more or fewer cam elements166may be present as necessary.

During use, the spokes170of the sprocket110move along the cam surface158depending upon the direction and magnitude of the impulse loads between the engine56and the drivetrain. More specifically, the cam surface158of the cam slider114and the spokes170of the sprocket110form a torque-buffering interface therebetween.

When no impulse loads are being transmitted between the engine56and the drivetrain (e.g., during smooth acceleration, cruising, or idling) the spokes170contact the cam surface158at a neutral point174, which roughly corresponds with the axially lowest point of each cam element166. As such, the biasing members152bias the cam slider114towards the neutral point174.

When a large forward impulse is experienced by the compensator assembly86(e.g., a sudden increase in crankshaft RPM), the spokes170of the sprocket110move along a first portion178of the cam surface158in direction A (FIG. 6), which in turn forces the cam slider114axially away from the distal end74of the crankshaft62and against the biasing members152. The larger the impulse load, the further the spokes170travel along the first portion178of the cam surface158in direction A.

In contrast, a large rearward load (e.g., sudden decrease in engine RPM) causes the spokes170of the sprocket110to move in direction B along the second portion182of the cam surface158, opposite direction A. Although the rearward load causes the spokes170to move in the opposite direction, the cam slider114is still forced axially away from the distal end74of the crankshaft62and into the biasing members152. The larger the impulse, the further the spokes70will move along the second portion182of the cam surface158in direction B.

Illustrated inFIG. 6, adjacent cam elements166are separated by peaks168between the first portions178and the second portions182of adjacent cam elements166. In the illustrated construction, the contour of the first portion178is less steep than the contour of the second portion182. In alternate constructions the contour of both the first and second portions178,182may be altered as necessary to vary the operational characteristics of the compensator assembly86.

Illustrated inFIGS. 7 and 8, the sprocket110is substantially disk shaped, having an inner race186, an outer race190, and a plurality (e.g., three) of spokes170extending radially therebetween. The sprocket110also includes two axially-spaced rings of sprocket teeth194configured to engage a double-row chain (not shown) in mechanical communication with a clutch or other transmission input. However, in alternate constructions the outer race190may include provisions for a belt, drive gears, and the like. When assembled, the sprocket110is rotatably supported on a retainer210to form an interface therebetween.

During operation, the sprocket110is driven with torque compensation by the cam slider114by way of the cam surfaces158engaging the spokes170. The sprocket110in turn is configured to drive the rear wheel54through the remainder of the drivetrain. The sprocket110is not internally splined, but rather includes a smooth bore172rotatably supported on the retainer210(FIG. 2). Therefore, the sprocket110is rotatable relative to the cam slider114, the shaft extension118, and the crankshaft62about the crankshaft axis66within a predetermined range.

The sprocket110also includes a plurality of lubrication channels198extending substantially radially along the spokes170(FIGS. 7 and 8). The channels198are sized to allow oil to infiltrate the interface between the cam surface158of the cam slider114and the spokes170to form a protective film. In the illustrated construction, each spoke170contains two channels198on opposite axial sides thereof substantially corresponding to the areas the cam surface158contacts the spokes170. However, in alternate constructions more or fewer channels198may be present as necessary.

The sprocket110is axially constrained by a thrust bearing202positioned between the sprocket inner race186and a flange206of the retainer210. During operation, the cam slider114is forced axially outwardly, towards the distal end74of the crankshaft62which in turn forces the sprocket110axially outwardly and into contact with the thrust bearing202. In alternate constructions, a polymer thrust washer208with lubrication grooves209formed therein could be used (FIG. 17).

As shown inFIGS. 9-12, the compensator assembly86further includes a retention assembly122including the retainer210, and a retainer bolt214. The retainer assembly122is configured to axially retain the sprocket110, cam slider114, and shaft extension118on the distal end74of the crankshaft62. In the illustrated construction, the retainer210is coupled to the distal end74of the crankshaft62by the retainer bolt214which in turn is threaded into a threaded aperture formed in the distal end74of the crankshaft62. More specifically, the retainer bolt214includes a head218having a substantially conical outer surface216that expands radially outwardly as it extends axially inwardly, or towards the retainer210(FIGS. 2 and 12).

During use, the oil dripping from the apex102of the ribs98of the primary cover90lands on the conical outer surface216of the head218where centrifugal force from the rotation of the compensator assembly86urges the oil axially inward towards the retainer210and into a pocket222formed at an axially distal end238thereof. In the illustrated construction, the conical outer surface216of the head218is smooth to assure the maximum amount of fluid is directed toward the retainer210and not flung off as the compensator assembly86rotates with the crankshaft62. When assembled, incident oil moves axially inwardly along the outer surface216of the bolt head218until it reaches the innermost point, where it is flung off and is captured by an oil groove226of the retainer210(described below). The oil is then directed by the retainer210to one or more interfaces throughout the compensator assembly86.

Illustrated inFIGS. 9-11, the retainer210of the compensator assembly86is substantially cylindrical in shape having a central bore230extending therethrough. The central bore230of the retainer210includes a first portion234proximate the distal end238, and a second portion242extending axially from the first portion234away from the distal end238to define a plurality of interior spline teeth240. When assembled, the interior spline teeth of the second portion242engage the exterior spline teeth78of the crankshaft62causing the crankshaft62and the retainer210to rotate as a unit. Furthermore, the retainer210is coupled on the distal end74of the crankshaft62by the retainer bolt214.

The retainer210also defines an oil groove226positioned proximate the distal end238of the retainer210. The oil groove226is open on the radially inwardmost side and is at least partially defined by a lip250extending axially from the retainer's distal end238. The lip250also at least partially defines a pocket222.

The retainer210also defines a plurality (e.g., six) of lubrication passageways258extending axially through the retainer210and positioned radially outwardly of the first portion234of the bore230. In the illustrated construction, the passages258extend between the distal end238of the retainer210and one or more of the interfaces of the compensator assembly86. More specifically, each passageway258is in fluid communication with the pocket222and some combination of the interfaces formed between the sprocket110, the retainer210, the shaft extension118, and the cam slider114. In the illustrated construction, the distal end of the lip250is positioned radially inward of the radially outermost point of the lubrication passages258(FIG. 11).

The retainer210also includes a first set of apertures262, each positioned a first axial distance from the distal end238and extending between the outer surface266of the retainer210and a corresponding one of the passageways258. The first set of radial apertures262are positioned proximate the flange206and are in fluid communication with the interface formed between the bore172in the inner race186of the sprocket110and the outer surface266of the retainer210.

The retainer210also includes a second set of radial apertures270, each positioned a second axial distance from the distal end238greater than the first distance. More specifically, the second set of radial apertures270are open to the axially inward end of the retainer210. The second set of radial apertures270extend between the outer surface266of the retainer210and a corresponding one of the passageways258. When assembled, the radially inward end of the retainer210is received within the pocket146of the shaft extension118causing each of the second set of apertures270to be substantially axially aligned with the oil groove134. As such, centrifugal force caused by rotation of the compensator assembly86forces oil through the second set of apertures270and radially outwardly to be collected by the oil groove134which in turn distributes the oil as described above.

During operation, oil is collected by the compensator assembly86from within the primary cover90to be distributed to various interfaces within the assembly. More specifically, splash oil is collected by the ribs98of the primary cover90where the oil is funneled towards the apex102. The oil then drips from the apex102onto the conically shaped outer surface216of the head218of the retaining bolt214. The oil then proceeds axially inwardly and radially outwardly along the conical surface216until it is radially thrown off and collected by the oil groove226of the retainer210.

Once collected in the oil groove226, the oil enters the plurality of axial passageways258and continues axially inwardly via the rotation of the compensator86. As the oil continues inwardly, a first portion of the oil is expelled out the first set of apertures262to lubricate the interface formed between the bore172of the sprocket110and the retainer210(hereafter Interface W).

The remainder of the oil continues axially inwardly until it reaches the second set of apertures270. The oil is then thrown off radially and collected by the oil groove134of the shaft extension118. The oil within the oil groove134is then directed through the plurality of openings150to lubricate the exterior splines130(e.g., the interface formed between the cam slider114and the shaft extension118; hereafter Interface X).

As oil continues to build at interface W, excess oil will begin to leak and continue radially outwardly due to the rotation of the compensator assembly86. More specifically, oil leaking from interface W continues radially outwardly to lubricate the thrust bearing202(hereafter interface Y) and along the channels198in the spokes110to lubricate the contacting point between the cam surface158and the spokes170(hereafter Interface Z, not shown).

In summary, the compensator assembly86of the present invention provides full lubrication to all the interfaces within the assembly without the use of a pump. Rather, the compensator assembly86includes a passive lubrication system that harnesses the centrifugal force generated by the rotation of the compensator assembly86with the crankshaft62to collect and distribute oil to the one or more interfaces.

FIGS. 13-16illustrate a second embodiment of the compensator assembly86′ for use with a wide-body motorcycle. The compensator assembly86′ is substantially similar to and operates in much the same way as the compensator assembly86described above. As such, similar elements have been given the same number with an added prime. Only the differences between the two constructions will be described herein.

Illustrated inFIG. 13, the primary cover90′ of the compensator assembly86′ is positioned a greater distance from the distal end72′ of the crankshaft62′ (as compared with compensator assembly86). To ensure oil dripping from the apex102′ of the ribs98′ is directed into the oil groove226′, a cap290′ is coupled to the distal end238′ of the retainer210′.

Illustrated inFIG. 14-16, the cap290′ is removably coupled to the distal end238′ of the retainer210′ to extend the axial “reach” of the compensator assembly86′ for gathering oil from the primary cover90′. The cap290′ is generally hexagonal in shape, having a convex tip294′, an annular sheath298′, and a plurality of tabs302′. In the illustrated construction, the tabs302′ are configured to snap fit onto the distal end238′ of the retainer210′, allowing for easy removal and access to the retention bolt214′.

Similar to the conical outer surface of the bolt head218′, the convex tip294′ expands radially as it extends axially inwardly. As such, oil dripped onto the cap290′ (e.g., via the apex102′) will be urged axially inwardly by centrifugal force towards the retainer210′ as the compensator86′ rotates. The outer surface of the convex tip294′ is substantially smooth to maximize the amount of oil conveyed to the retainer210′.

The sheath298′ of the cap290′ at least partially encompasses a portion of the tip294′, positioned radially outwardly leaving a gap therebetween for oil to pass. The sheath298′ at least partially overlaps a portion of the tip294′ and is coupled thereto by a plurality of supports306′ extending therebetween. The sheath298′ captures excess oil that may have been discharged from the tip294′ during use.

During use, oil is deposited on the tip294′ of the cap290′, where it travels axially inwardly until it is deposited within the pocket222′. Once within the pocket222′, the oil distribution is similar to that described above.