Double Differential Assembly

Abstract

A differential assembly with a first differential drive (15) having a differential cage (14) rotatingly drivable around an axis of rotation (A), a plurality of differential spur gears (17) rotating with the differential cage (14), and crown gears (18, 19) coaxial with the axis of rotation (A) and engaging the spur gears (17). A second differential drive (16) is arranged inside the first differential drive (15), and has a differential carrier (20), a plurality of differential gears (26) rotating jointly with the differential carrier (20), and sideshaft gears (27, 28) coaxial with the axis of rotation (A) and engaging the differential gears (26). The first crown gear (18) is connected in respect of drive to the differential carrier (20) of the second differential drive (16) and the second crown gear (19) is connected in respect of drive to a hollow shaft (22) extending coaxially relative to the axis of rotation (A).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of this invention, reference should be made to the embodiments illustrated in greater detail in the accompanying drawings and described below by way of examples of the invention.

FIG. 1 shows the basic principles of a driving axle of a four-wheel drive motor vehicle having an inventive differential assembly in a first embodiment.

FIG. 2 is a longitudinal section through the differential assembly according to FIG. 1 in a modified embodiment.

FIG. 3 is a longitudinal section through an inventive differential assembly in a third embodiment.

FIG. 4 is a longitudinal section through a differential assembly in a fourth embodiment.

FIG. 5 shows an inventive differential assembly in a fifth embodiment in half a longitudinal section (upper half of the Figure) and in a circumferential section (lower half of the Figure).

FIG. 6 shows an inventive differential assembly in a sixth embodiment in half a longitudinal section (upper half of the Figure) and in a circumferential section (lower half of the Figure).

Claims

1. A differential assembly for use in the driveline of a motor vehicle with a plurality of driven axles, comprising: a first differential drive in the form of a crown gear differential, said first differential drive having a differential cage rotatingly drivable around an axis of rotation (A), a plurality of spur gears as differential gears and which rotate jointly with the differential cage, and a first crown gear and a second crown gear which are arranged coaxially relative to the axis of rotation (A) and which engage the spur gears; anda second differential drive arranged coaxially relative to the axis of rotation (A) inside the first differential drive, said second differential drive having a differential carrier, a plurality of differential gears rotating jointly with the differential carrier, and a first sideshaft gear and a second sideshaft gear which are arranged coaxially relative to the axis of rotation (A) and which engage the differential gears,wherein the first crown gear is connected to the differential carrier of the second differential drive in a rotationally fast way and wherein the second crown gear is connected in a rotationally fast way to a hollow shaft extending coaxially relative the axis of rotation (A).

2. A differential assembly according to claim 1, wherein the differential cage comprises a first cage part, a second cage part and an annular-disc-shaped driving gear which is held between said cage parts and in which the spur gears are received.

3. A differential assembly according to claim 2, wherein the spur gears are rotatably held in the annular-disc-shaped driving gear in radial recesses starting from an inner circumferential face.

4. A differential assembly according to claim 1, wherein the first crown gear is annular-disc-shaped and comprises inner teeth, which, in a rotationally fast way, engage corresponding outer teeth of the differential carrier of the second differential drive.

5. A differential assembly according to claim 1, wherein the second crown gear is annular-disc-shaped and comprises inner teeth which, in a rotationally fast way, engage corresponding outer teeth of a hollow gear which is connected to the hollow shaft.

6. A differential assembly according to claim 1, wherein the crown gears are axially displaceable and each comprise a contact face extending in an axially opposite direction to the crown gear teeth, wherein, between the contact face of the first crown gear and the differential cage, there is provided a first friction coupling and, wherein, between the contact face of the second crown gear and the differential cage, there is provided a second friction coupling for generating a locking moment.

7. A differential assembly according to claim 6, wherein the first and the second friction coupling are multi-plate couplings and comprise outer plates and inner plates which are arranged so as to alternate in the axial direction and which are axially displaceable.

8. A differential assembly according to claim 6, wherein inner teeth of inner plates of the first friction coupling engage outer teeth of the differential carrier in a rotationally fast and axially displaceable way, and outer teeth of outer plates engage inner teeth in the differential cage in a rotationally fast and axially displaceable way.

9. A differential assembly according to claim 6, wherein inner teeth of inner plates of the second friction coupling engage outer teeth of the hollow gear in a rotationally fast and axially displaceable way, and outer teeth of outer plates engage inner teeth in the differential cage in a rotationally fast and axially displaceable way.

10. A differential assembly according to claim 1, wherein the crown gears are axially displaceable and each comprise a conical contact face extending in an axially opposite direction to the crown gear teeth, wherein, between the conical contact face of the first crown gear and the differential cage there is provided a first pair of friction faces and wherein, between the conical contact face of the second crown gear and the differential cage, there is provided a second pair of friction faces for generating a locking moment.

11. A differential assembly for use in the driveline of a motor vehicle with a plurality of driven axles, comprising: a first differential drive in the form of a crown gear differential, said first differential drive having a differential cage which is rotatingly drivable around an axis of rotation (A), a first crown gear firmly connected to the differential cage, a second crown gear rotatably held in the differential cage coaxially relative to the axis of rotation (A), and a plurality of pairs of spur gears which engage one another and of which a first spur gear engages the first crown gear and a second spur gear engages the second crown gear;a second differential drive which is arranged coaxially relative to the axis of rotation (A) and inside the first differential drive, said second differential drive having a differential carrier, a plurality of differential gears rotating jointly with the differential carrier around the axis of rotation (A), and a first sideshaft gear and a second sideshaft gear which are arranged coaxially relative to the axis of rotation (A) and engage the differential gears;wherein the spur gears of the crown gear differential rotate jointly with the differential carrier of the second differential drive around the axis of rotation (A) and wherein the second crown gear is connected in a rotationally fast way to a hollow shaft extending coaxially relative to the axis of rotation (A).

12. A differential assembly according to claim 11, wherein at least one of the two spur gears intersects the axis of rotation (A) at a distance therefrom, and wherein the crown gear engaging the corresponding spur gear comprises helical teeth.

13. A differential assembly according to claim 11, wherein the differential cage comprises a first cage part, a second cage part and a disc-shaped driving gear held axially between said cage parts.

14. A differential assembly according to claim 11, wherein the first crown gear is integral with the differential cage.

15. A differential assembly according to claim 11, wherein, on its radial outside, the differential carrier comprises an annular-disc-shaped portion holding the pairs of spur gears and, on its radial inside, the differential carrier comprises a sleeve-shaped portion receiving the differential gears.

16. A differential assembly according to claim 15, wherein the annular-disc-shaped portion substantially fills a chamber formed between the crown gears.

17. A differential assembly according to claim 15, wherein, by inner cylindrical faces, the first and the second crown gears are rotatably supported on the sleeve-shaped portion.

18. A differential assembly according to claim 1, wherein, with reference to the axis of rotation (A), the spur gears are positioned axially in the region of the differential gears.

19. A differential assembly according to claim 11, wherein, with reference to the axis of rotation (A), the spur gears are positioned axially in the region of the differential gears.

20. A differential assembly according to claim 1, wherein the first crown gear and the second crown gear comprise the same number of teeth or different numbers of teeth.

21. A differential assembly according to claim 11, wherein the first crown gear and the second crown gear comprise the same number of teeth or different numbers of teeth.

22. A differential assembly according to claim 1, wherein the second differential drive is received in the differential cage, and the sideshaft gears are axially supported against the differential cage by contact faces.

23. A differential assembly according to claim 11, wherein the second differential drive is received in the differential cage, and the sideshaft gears are axially supported against the differential cage by contact faces.