Integrated viscous transmission in a differential

• US 20020187873A1
• Filed: 08/02/2002
• Published: 12/12/2002
• Est. Priority Date: 10/04/2000
• Status: Active Grant

• Current Assignee: GKN Driveline North America Incorporated (Melrose Industries Plc)
• Original Assignee: GKN Driveline North America Incorporated (Melrose Industries Plc)
• Inventors: Gassmann, Theodor
• Granted Patent: US 6,592,488 B2
• Time in Patent Office: Days
• US Class Current: 475/230
• CPC Class Codes: B60K 17/351 comprising a viscous clutch
• CPC Class Codes: B60K 23/0808 for varying torque distribution between driven axles, e.g. by transfer clutch
• CPC Class Codes: F16D 35/005 with multiple lamellae
• CPC Class Codes: F16H 48/08 comprising bevel gears
• CPC Class Codes: F16H 48/26 using fluid action, e.g. viscous clutches

Abstract

A differential drive for use on a vehicle to control the transfer of torque between the front and rear axles of a vehicle. The differential drive includes a rotatably driven differential housing supported in a housing. The differential drive also includes a differential gear set arranged and supporting in the differential housing. The differential gear set has at least two side shafts gears and at least two differential gears. The differential drive also includes a torque distribution device having a viscous transmission. The viscous transmission has an inner hub and an outer casing. The inner hub is connected to a first side shaft. The outer casing is connected to one of the side gears. The viscous transmission also connects the output of the first side shaft to one of the side shaft gears.

Claims

1. A differential drive for use on a vehicle, said differential drive including:

a rotatably driven differential housing supported in a housing;

a differential gear set arranged and supported in said differential housing; and

a torque distribution device adjacent to said differential gear set, said torque distribution device including a passive speed sensing unit, said torque distribution device connecting one output of a side shaft with one output of a side shaft gear, said torque distribution device is arranged to control torque between a front axle system and a rear axle system of the vehicle.

2. The differential drive of claim 1 wherein said differential gear set includes two side shaft gears arranged and supported in said differential housing.

3. The differential drive of claim 2 wherein said differential gear set further includes at least two differential gears which engage said side shaft gears and are rotatably supported in said differential housing.

4. The differential drive of claim 1 wherein said differential gear set obtains a speed difference between said front and rear axle systems.

5. The differential drive of claim 1 wherein said passive speed sensing unit rotates with axle speed and provides torque transfer to a first side shaft.

6. The differential drive of claim 5 wherein a second side shaft gear is driven with said same torque via said differential gear set.

7. The differential drive of claim 6 wherein said differential gear operates as an open differential between said first and said second side shaft gears, said open differential allows vehicle wheels to spin freely.

8. The differential drive of claim 1 wherein a speed difference between said rear and said front axle creates slip across said passive speed sensing unit which generates torque.

9. The differential drive of claim 8 wherein said slip across said passive speed sensing unit is approximately twice said speed difference between said front and rear axle.

10. The differential drive of claim 1 wherein said passive speed sensing unit includes a viscous transmission.

11. The differential drive of claim 10 wherein said viscous transmission runs in oil which reduces effort for bearings and seals while improving cooling of the differential drive.

13. The torque distribution device of claim 12 wherein said viscous transmission provides torque transfer to one side shaft.

14. The torque distribution device of claim 13 wherein said second side shaft is driven with said same torque via said rear differential.

15. The torque distribution device of claim 12 wherein a speed difference between said front and rear transaxle will create slip across said viscous transmission and generate torque.

16. The torque distribution device of claim 15 wherein said slip across said viscous transmission is approximately twice said speed difference between said front and rear differential.

17. The torque distribution device of claim 12 wherein said viscous transmission runs in axle oil.

18. The torque distribution device of claim 17 wherein said axle oil minimizes efforts for bearings and seals and improves cooling of said viscous transmission.

19. The torque distribution device of claim 12 wherein said viscous transmission is partially filled with a highly viscous oil.

12. An improved torque transmission device for use on a vehicle drive train system having an engine, a transaxle, a front and a rear differential, a propeller shaft connecting the front and rear differential, a right and left side shaft extending from each of the front and rear differentials, said improved torque distribution device including:

a differential gear set located within the rear differential, the torque distribution device engages with said differential gear set; and

.

the torque distribution device including a viscous transmission engaged with one of a side shaft and one of a side shaft gear of said differential gear set, said viscous transmission runs with an axle speed and provides torque transfer between said front and rear differentials.

20. A differential drive for use on a vehicle to control the transfer of torque between front and rear axle systems of the vehicle, said differential drive including:

a rotatably driven differential housing supported a housing;

a differential gear set arranged and supported in said differential housing, said differential gear set having at least two side shaft gears and at least two differential gears; and

a torque distribution device including a viscous transmission, said viscous transmission having an inner hub and an outer casing, said inner hub connected to a first side shaft, said outer casing connected to a side shaft gear; and

said viscous transmission connects output of said first side shaft to one of said side shaft gears.