Transfer Case With Torque Limiting Clutch Assembly

Abstract

A power transfer unit is provided with a torque limiting coupling that limits the amount of torque that can be transferred to the driveline components when torque peaks occur while torque is transferred to the non-slipping wheels. The torque limiting coupling includes an engagement member disposed between an input from a driving member and an output to a driven member. The engagement member is located radially between and provides a frictional engagement between the input and the output. The engagement member is capable of slipping under heavy torque loads in order to protect the driveline components.

Description

DRAWINGS

The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

FIG. 1 is a schematic view of a four-wheel drive vehicle equipped with a power transfer unit having an actively-controlled torque transfer clutch and a control system according to the present disclosure;

FIG. 2 is a schematic diagram of the power transfer unit of FIG. 1 defining a full-time two-speed transfer case having a chain drive assembly equipped with a torque limiting coupling according to the present invention;

FIG. 3 is a sectional view of a torque limiting coupling embodying the device schematically shown in FIG. 2; and

FIG. 4 is a schematic diagram of an alternative installation of the torque limiting chain drive assembly within the full-time transfer case of FIG. 2

Claims

1. A power transfer unit for a vehicle having a powertrain and a driveline, comprising: an input member driven by the powertrain;an output member driving the driveline; anda torque limiting coupling disposed between said input and output members, said torque limiting coupling including a cone clutch having an outer conical surface engaging an inner conical surface formed on said input member and an inner conical surface engaging an outer conical surface formed on said output member, and a spring biasing mechanism applying a spring load on said cone clutch for establishing frictional engagement between said conical surfaces of said cone clutch and said conical surfaces on said input and output members.

2. The power transfer unit of claim 1 wherein said torque limiting coupling includes a second cone clutch having an outer conical surface engaging a second inner conical surface formed on said input member and an inner conical surface engaging a second outer conical surface formed on said output member.

3. The power transfer unit of claim 2 wherein said first cone clutch is disposed between said spring biasing mechanism and said second cone clutch.

4. The power transfer unit of claim 2 wherein said first and second inner conical surfaces on said input member extend in opposite directions relative to a rotary axis of said output member.

5. The power transfer unit of claim 2 wherein said input member is a sprocket and said output member is a shaft.

6. A transfer case comprising: an input shaft;a first output shaft driven by said input shaft;a second output shaft; anda torque transfer mechanism having a driving member driven by said first output shaft, a driven member driving said second output shaft, and a torque limiting coupling therebetween, said torque limiting coupling including an engagement member having a first tapered surface engaging a tapered surface on said driving member and a second tapered surface engaging a tapered surface on said driven member, and a biasing mechanism for biasing said engagement member into frictional contact with said driven member and said driving member.

7. The transfer case of claim 6 further comprising a first sprocket fixed to said first output shaft, a second sprocket supported on said second output shaft, and a transfer device for causing said first sprocket to drive said second sprocket, and wherein said engagement member is disposed between said second sprocket and said second output shaft such that said driving member is fixed to said second sprocket and said driven member is fixed to said second output shaft.

8. The transfer case of claim 7 wherein said engagement member is a cone clutch having its first tapered surface in frictional engagement with a tapered surface formed on said second sprocket and its second tapered surface in frictional engagement with a tapered surface in frictional engagement with a tapered surface formed on said second output shaft.

9. The transfer case of claim 6 further comprising a first sprocket supported on said first output shaft, a second sprocket fixed to said second output shaft, and a transfer device for causing said first sprocket to drive said second sprocket, and wherein said engagement member is disposed between said first sprocket and said first output shaft such that said driving member is fixed to said first sprocket and said driven member is fixed to said first output shaft.

10. The transfer case of claim 9 wherein said engagement member is a cone clutch having its first tapered surface in frictional engagement with a tapered surface formed on said first sprocket and its second tapered surface in frictional engagement with a tapered surface in frictional engagement with a tapered surface formed on said first output shaft.

11. The transfer case of claim 6 wherein said engagement member includes a first cone clutch.

12. The transfer case of claim 13 wherein said engagement member includes a second cone clutch displaced axially from said first cone clutch.

13. A transfer case comprising: an input shaft;a first output shaft in a driven engagement with said input shaft;a second output shaft in a driven engagement with said first output shaft, one of an input from a driving member and an output to a driven member including an outer portion extending into an inner portion of the other of said input from said driving member and said output to said driven member; anda torque transfer mechanism including an engagement member at least partially disposed between and frictionally engaged with at least one of said outer portion and said inner portion.

14. The transfer case of claim 13 wherein said engagement member is frictionally engaged with both said outer portion and said inner portion.

15. The transfer case of claim 13 further comprising a first sprocket arranged around said first output shaft and a second sprocket arranged around said second output shaft, said engagement member disposed between at least one of said first sprocket and said first output shaft and said second sprocket and said second output shaft.

16. The transfer case of claim 13 wherein one of said input and said output includes an inner surface disposed at a first angle relative to an axis of rotation of said driving member, said engagement member including an outer surface disposed at a second angle relative to said axis of rotation of said driving member and engaged with said inner surface.

17. The transfer case of claim 13 wherein one of said input and said output includes an outer surface disposed at a first angle relative to an axis of rotation of said driving member, said engagement member including an inner surface disposed at a second angle relative to said axis of rotation of said driving member and engaged with said outer surface.

18. A transfer case comprising: an input shaft;a first output shaft in a driven engagement with said input shaft;a first sprocket arranged around said first output shaft;a second output shaft in a driven engagement with said first output shaft;a second sprocket arranged around said second output shaft, said second sprocket in a driven engagement with said first sprocket; anda torque transfer mechanism at least partially disposed between at least one of said first output shaft and said first sprocket and said second output shaft and said second sprocket.