Multiple axle drive vehicle with overrunning roller clutch hubs

• US 5,036,939 A
• Filed: 08/09/1989
• Issued: 08/06/1991
• Est. Priority Date: 08/28/1987
• Status: Expired due to Term

• Current Assignee: Hilliard Corporation, Polaris Industries Incorporated (Polaris Inc.)
• Original Assignee: Hilliard Corporation, Polaris Industries Incorporated (Polaris Inc.)
• Inventors: Eastman, Robert, Johnson, Mitchell, Ochab, David C.
• Primary Examiner(s): Hill, Mitchell J.
• Application Number:
  US07/391,774
• Time in Patent Office: 727 Days
• Field of Search: 192/38, 192/36, 192/35, 192/50, 192/54, 180/233, 180/247, 180/248, 180/249
• US Class Current: 180/233
• CPC Class Codes: B60K 17/3515 with a clutch adjacent to traction wheel, e.g. automatic wheel hub
• CPC Class Codes: F16D 41/105 the intermediate members being of circular cross-section, of only one size and wedging by rolling movement not having an axial component between inner and outer races, one of which is cylindrical

Abstract

A multiple driven axle vehicle, such as a four-wheel drive recreational vehicle having its front, steerable wheels being optionally driven by providing double acting overrunning clutches in the hubs of the front wheels. A transmission mechanism is provided for driving the front, optionally driven wheels slower than the driving surface otherwise drives those wheels so that the slower driven wheels overrun and do not engage when the steerable wheels are turned as the vehicle is driven through a turn, thereby eliminating the need for a differential between the steerable wheels and between the front and rear wheels. The overrunning roller clutches of the optionally driven hubs desirably include an intermittent friction apparatus operative between the roller cage and the vehicle chassis to intermittently exert a force tending to retard rotation of the cage with respect to the chassis, thereby indexing the roller cage and rollers to the forward or reverse engagable position. The intermittent nature of the friction permits the roller cage and rollers to return to the central, neutral position when rotation of the cage with respect to the chassis stops. The roller clutches further include a generally cylindrical cam driven by the transmission and located radially inward of the rollers and roller cage. The cam surface includes a ridge associated with at least some of the rollers for inhibiting inertial movement of the rollers from the forward engagable position to the reverse engagable position, as for example during sudden braking.

Claims

1. A multiple driven axle vehicle including a chassis, an engine mounted to the chassis, a pair of front wheels and a pair of rear wheels, one of said pairs being steerable and each wheel of at least one of said paris including a hub having a double acting overrunning clutch, each of the overrunning clutches including

a generally cylindrical cam driven by the transmission means and having an outer surface and a longitudinal axis;

a race coaxial of the cam and having an inner generally smooth cylindrical surface;

a plurality of generally cylindrical, circumferentially spaced rollers interposed between the cam surface and the race surface, the rollers having longitudinal axes generally parallel to the cam axis;

spring means for urging the rollers generally radially inwardly with respect to the cam axis; and

a roller cage rotatable with respect to the cam and the race, the roller cage spacing the rollers circumferentially from one another and limiting circumferential movement of the rollers with respect to the cage while permitting radial movement thereof;

the cam surface having a circumferential region associated with each roller, said cam surface being configured so that as the roller cage and rollers rotate in a given direction with respect to the cam, the rollers are urged radially outwardly from a free-wheeling position into a driving position wherein the rollers contact the race surface to operatively engage the cam with the race whenever the transmission means attempts to rotate faster than the wheel;

at least one of the circumferential regions of the cam surface including impediment means tending to inhibit movement of the associated roller from the free-wheeling position to the driving position upon sudden reduction of the rotational speed of the cam;

and transmission means for transmitting rotational power from the engine to the wheels, the transmission means being geared to drive one pair of wheels sufficiently slower than the other pair of wheels so that the overrunning clutches of the slower driven wheels do not engage when the steerable wheels are turned as the vehicle is driven through a turn, the overrunning clutches and transmission means thereby coacting to eliminate the need for a differential between the slower driven wheels.

2. The vehicle of claim 1 wherein the overrunning clutch includes intermittent friction means operative between the roller cage and the vehicle chassis to intermittently exert a force tending to retard rotation of the cage with respect to the chassis.

3. The vehicle of claim 2 wherein the intermittent friction means includes a projection carried by one of the frame and the roller cage, and a movable plunger carried by the other of the frame and the roller cage, the plunger being oriented to momentarily frictionally engage the projection as the roller cage rotates with respect to the frame.

4. The vehicle of claim 3 wherein the plunger is movable along a longitudinal axis and includes means for biasing the plunger toward said one of the frame and the roller cage.

5. The vehicle of claim 3 wherein an end of the plunger located adjacent said one of the frame and the roller cage is generally hemi-spherically shaped.

6. The vehicle of claim 3 wherein the projection is oriented along a radius extending from an axis about which the roller cage rotates, the projection having a generally tapered cross-section taken along a plane normal to said radius.

7. The vehicle of claim 1 including two such impediment means associated with each of said at least one circumferential region.

8. The vehicle of claim 7 wherein the area of the cam surface between said two impediment means is generally concave in cross-section, each of said two impediment means comprising a longitudinal ridge.

9. The vehicle of claim 7 including two such adjacent circumferential regions each having two such impediment means, the area of the cam surface between the impediment means of one of said regions and the adjacent impediment means of the other region being generally convex in cross-section.

10. The vehicle of claim 1 wherein the cam has a generally constant cross-section along its length, each said circumferential region being defined by a pair of lines comprising boundaries of adjacent circumferential regions, each said line lying generally parallel to the cam axis and being located radially outwardly of other portions of the cam.

11. The vehicle of claim 1 wherein each such circumferential region includes a central area corresponding to disengagement of the associated roller from the race, and respective forward and reverse engaged areas on opposite sides of the central area corresponding to engagement of the associated roller with the race in forward and reverse rotational directions respectively.

12. The vehicle of claim 11 wherein the impediment means comprises a ridge located between at least a portion of the central area and the reverse engaged area.

13. The vehicle of claim 11 wherein the impediment means is located between the central area and the forward engageable area and another impediment means is located between the central area and the reverse engagable area.

14. The vehicle of claim 1 wherein the vehicle includes four wheels, the front wheels being steerable and driven slower than the rear wheels.

15. The vehicle of claim 14 wherein the front wheels are driven about 10% to about 30% slower than the rear wheels.

16. The vehicle of claim 1 wherein the overrunning clutch includes electromagnetically controllable friction means operative between the roller cage and the vehicle chassis to selectively exert a force tending to retard rotation of the cage with respect to the chassis.

17. The vehicle of claim 16 wherein the electromagnetically controllable friction means includes an electromagnetic coil carried by the vehicle chassis, and an armature plate interposed between the vehicle chassis and the roller cage, the armature plate being movable therebetween in response to activation of the coil to exert a force tending to retard rotation of the cage with respect to the chassis.

18. The vehicle of claim 17 wherein the chassis includes an inner, generally annular pole, and an outer, generally annular pole, each associated with the coil and having an annular surface adjacent to the armature plate.

19. The vehicle of claim 18 wherein one of the poles extends axially beyond the other so that the armature plate may contact only one of the poles

20. The vehicle of claim 17 wherein the armature plate comprises a generally flat, annular ring having a plurality of prongs extending axially therefrom, the prongs being receivable in complimentary cavities in the roller cage and functioning to transmit rotational drag forces to the roller cage.

21. The vehicle of claim 16 wherein the electromagnetic friction means include switch means associated with the transmission means for energizing the friction means when the vehicle is shifted into a forward gear, and for de-energizing the friction means when the vehicle is shifted out of the forward gear.

22. The vehicle of claim 20 wherein the electromagnetic friction means includes manual switch means operable by a rider of the vehicle to manually engage the friction means.

23. The vehicle of claim 22 wherein the vehicle includes reverse speed limiter means for limiting the reverse speed of the vehicle, and wherein the manual switch cans is also operable to override the reverse speed limiter means.

24. A multiple driven axle vehicle including a chassis an engine mounted to the chassis, a pair of front wheels and a pair of rear wheels, one of said pairs being steerable and each wheel of at least one of said pairs including a hub having a double acting overrunning clutch, and transmission means for transmitting rotational power from the engine to the wheels, the transmission means being geared to drive one pair of wheels sufficiently slower than the other pair of wheels so that the overrunning clutches of the slower turned wheels do not engage when the steerable wheels are turned as the vehicle is driven through a turn, each of the overrunning clutches including

a generally cylindrical cam driven by the transmission means and having an outer surface and a longitudinal axis;

a race coaxial of the cam and having an inner generally smoother cylindrical surface;

a plurality of generally cylindrical, circumferentially spaced rollers interposed between the cam surface and the race surface, the rollers having longitudinal axes generally parallel to the cam axis;

spring means for urging the rollers generally radially inwardly with respect to the cam axis; and

a roller cage rotatable with respect to the cam and the race, the roller cage spacing the rollers circumferentially from one another and limiting circumferential movement of the rollers with respect to the cage while permitting radial movement thereof;

the cam surface having a circumferential region associated with each roller, said cam surface being configured so that as the roller cage and rollers rotate in a given direction with respect to the cam, the rollers are urged radially outwardly from a free-wheeling position into a driving position wherein the rollers contact the race surface to operatively engage the cam with the race whenever the transmission means attempts to rotate faster than the wheel, at least one of the circumferential regions of the cam surface including ridge means tending to inhibit inertial movement of the associated roller from the free-wheeling position to the driving position as when the hub is suddenly braked;

the overrunning clutch further including intermittent friction means operative between the roller cage and the vehicle chassis to intermittently exert a force tending to retard rotation of the cage with respect to the chassis.