AXLE ASSEMBLY AND VEHICLE

Abstract

Disclosed herein is an axle assembly and a heavy load vehicle comprising the axel assembly. The axle assembly comprises an interaxle differential configured to distribute torque to first and second axles. The interaxle differential comprises an input shaft and an output shaft. A first gear wheel is journaled in a first bearing about the input shaft. The input shaft is journaled in relation to the output shaft via a tapered roller bearing having a small end and a large end. A lubricant receiving space is fluidly connected to the small end of the tapered roller bearing, and the large end of tapered roller bearing is fluidly connected to the first bearing. Thus, the first bearing is lubricated when there exists a difference in rotational speed between the input and output shafts.

Claims

1. An axle assembly for a heavy load vehicle comprising: a housing; and an interaxle differential configured to distribute torque to a first axle and a second axle, wherein the interaxle differential comprises an input shaft and an output shaft each journaled in the housing and having a common rotational axis, the input shaft being journaled in relation to the output shaft, wherein the input shaft is connected to the first axle via a first gear wheel journaled in a first bearing about the input shaft, and the output shaft is configured to be connected to the second axle, wherein the interaxle differential further comprises a differential spider and at least one pinion gear, the differential spider being rotationally locked to the input shaft, and the at least one pinion gear engaging with the first gear wheel and the output shaft, wherein the input shaft is journaled in relation to the output shaft via a tapered roller bearing having a small end and a large end, wherein a lubricant receiving space is provided in the housing, wherein the lubricant receiving space is fluidly connected to the small end of the tapered roller bearing, and wherein the large end of tapered roller bearing is fluidly connected to the first bearing.

2. The axle assembly according to claim 1, comprising a second gear wheel rotationally locked to the output shaft and configured to engage with the at least one pinion gear.

3. The axle assembly according to claim 2, wherein the tapered roller bearing is arranged in a first bearing seat provided at an end of the input shaft, and a second bearing seat provided in the second gear wheel.

4. The axle assembly according to claim 2, wherein a first lubricant path extends through and/or along, the second gear wheel from the lubricant receiving space to the small end of the tapered roller bearing.

5. The axle assembly according to claim 1, wherein a second lubricant path extends through and/or along the differential spider from the large end of the tapered roller bearing to the first bearing.

6. The axle assembly according to claim 5, wherein the second lubricant path extends through the first bearing.

7. The axle assembly according to claim 5, wherein the second lubricant path comprises a first annular space formed between the input shaft, the large end of the tapered roller bearing, and a first axial portion of the differential spider.

8. The axle assembly according to claim 7, wherein the first annular space is limited in an outer radial direction by a first ring-shaped member.

9. The axle assembly according to claim 8, wherein the first ring-shaped member is connected to the second gear wheel and extends in an axial direction towards the first axial portion of the differential spider.

10. The axle assembly according to claim 8, wherein the first ring-shaped member is connected to the differential spider and extends in an axial direction towards the second gear wheel.

11. The axle assembly according to claim 5, wherein the second lubricant path comprises a second annular space formed between the input shaft, a second axial portion of the differential spider, and the first gear wheel.

12. The axle assembly according to claim 11, wherein the second annular space is limited in an outer radial direction by a second ring-shaped member.

13. The axle assembly according to claim 12, wherein the second ring-shaped member is connected to the first gear wheel and extends in an axial direction towards the second axial portion of the differential spider.

14. The axle assembly according to claim 12, wherein the second ring-shaped member is connected to the differential spider and extends in an axial direction towards the first gear wheel.

15. The axle assembly according to claim 1, wherein the output shaft is journaled in the housing via the second gear wheel.

16. A heavy load vehicle comprising: a first driven axle; a second driven axle; and an axle assembly arranged between the first driven axle and the second driven axle, wherein the axle assembly comprises: a housing; and an interaxle differential configured to distribute torque to a first axle and a second axle, wherein the interaxle differential comprises an input shaft and an output shaft each journaled in the housing and having a common rotational axis, the input shaft being journaled in relation to the output shaft, wherein the input shaft is connected to the first axle via a first gear wheel journaled in a first bearing about the input shaft, and the output shaft is configured to be connected to the second axle, wherein the interaxle differential further comprises a differential spider and at least one pinion gear, the differential spider being rotationally locked to the input shaft, and the at least one pinion gear engaging with the first gear wheel and the output shaft, wherein the input shaft is iournaled in relation to the output shaft via a tapered roller bearing having a small end and a large end, wherein a lubricant receiving space is provided in the housing, wherein the lubricant receiving space is fluidly connected to the small end of the tapered roller bearing, and wherein the large end of tapered roller bearing is fluidly connected to the first bearing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Various aspects and/or embodiments of the invention, including its particular features and advantages, will be readily understood from the example embodiments discussed in the following detailed description and the accompanying drawings, in which:

[0029] FIG. 1 illustrates a heavy load vehicle according to embodiments,

[0030] FIGS. 2 and 3 illustrate a cross sections through an axle assembly according to embodiments, and

[0031] FIGS. 4a and 4b illustrate different embodiments of parts of the axle assembly of FIGS. 2 and 3.

DETAILED DESCRIPTION OF THE INVENTION

[0032] Aspects and/or embodiments of the invention will now be described more fully. Like numbers refer to like elements throughout. Well-known functions or constructions will not necessarily be described in detail for brevity and/or clarity.

[0033] FIG. 1 illustrates a heavy load vehicle 1 according to embodiments. The heavy load vehicle 1 exemplified in theses embodiments is a truck. The heavy load vehicle 1 comprises a first driven axle 3 and a second driven axle 5. The first and second driven axles 3, 5 are rear axles of the heavy load vehicle 1. The heavy load vehicle 1 further comprises an axle assembly 2 arranged between the first driven axle 3 and the second driven axle 5. The axle assembly 2 is an axle assembly according to any one of aspects and/or embodiments discussed herein. Naturally, the axle assembly 2 may be utilised in a vehicle comprising two driven front axles.

[0034] FIG. 2 illustrates a cross section through an axle assembly 2 according to embodiments. The axle assembly 2 comprises a housing 4, and an interaxle differential 7 configured to distribute torque to a first axle 3 and a second axle 5 of a heavy load vehicle, see above. Accordingly, the first axle 3 is a first driven axle 3, and the second axle 5 is a second driven axle 5. The rotational axis of the first axle 3 is indicated in FIG. 2.

[0035] The interaxle differential 7 comprises an input shaft 6 and an output shaft 8. The input shaft 6 is journaled in the housing 4 via a first roller bearing 11. The output shaft 8 is journaled in the housing 4 via a second roller bearing 13. The input and output shafts 6, 8 have a common rotational axis 9. Further, the input shaft 6 is journaled in relation to the output shaft 8. Thus, the input shaft 6 is securely journaled in the housing 4. The output shaft 8 may suitably be journaled at its other end, not shown in FIG. 2.

[0036] The input shaft 6 is connected to the first axle 3 via a first gear wheel 10. Radially outer cogs of the first gear wheel 10 engage with further gears in a known manner for driving the first axle 3. The output shaft 8 is configured to be connected to the second axle (not shown in FIG. 2). The interaxle differential 7 further comprises a differential spider 14 and at least one pinion gear 16. Mentioned purely as an example, the interaxle differential 7 may comprise four pinion gears 16.

[0037] The differential spider 14 is rotationally locked to the input shaft 6. More specifically, a hub of the differential spider 14 is rotationally locked to the input shaft 6. The at least one pinion gear 16 engages with the first gear wheel 10 and the output shaft 8. Cogs arranged on an axial face of the first gear wheel 10 engage with cogs of the at least one pinion gear. The at least one pinion gear 16 engages with the output shaft 8 via a second gear wheel 24, which is rotationally locked to the output shaft 8. The output shaft 8 is journaled in the housing 4 via the second gear wheel 24.

[0038] In these embodiments, the first gear wheel 10 and the second gear wheel 24 form differential gears of the interaxle differential 7. The interaxle differential 7 operates in an ordinary manner distributing torque between the first axle 3 and the second axle, permitting rotational speed differences between the first and second axles.

[0039] FIG. 3 illustrates a further cross section through the axle assembly 2 of FIG. 2. The input shaft 6 is journaled in relation to the output shaft 8 via a tapered roller bearing 18. The tapered roller bearing 18 has a small end 19 and a large end 21. The small end and large ends 19, 21 are axial ends of the tapered roller bearing 18. At the small end 19, the rollers of the tapered roller bearing 18 have a smaller diameter than at the larger end 21. When there is no rotational speed difference between the input and output shafts 6, 8, the entire tapered roller bearing 18 rotates together with the input and output shafts 6, 8, i.e. there is no rotational speed difference between the inner and outer races of the tapered roller bearing 18.

[0040] The first gear wheel 10 is journaled in a first bearing 12 about the input shaft 6. In these embodiments, the first bearing 12 is a plain bearing. According to alternative embodiments, the first bearing 12 may be a roller bearing, such as a needle roller bearing.

[0041] A lubricant receiving space 20 is provided in the housing 4. In these embodiments, the lubricant receiving space 20 is arranged between the housing 4 and the second gear wheel 24, extending at least partially about the output shaft 8. The lubricant receiving space 20 may receive lubricant from a lubricant pump (not shown), or from lubricant splashing within the housing 4. The lubricant receiving space 20 is fluidly connected to the small end 19 of the tapered roller bearing 18. The large end 21 of the tapered roller bearing 18 is fluidly connected to the first bearing 12.

[0042] When there exists a rotational speed difference between the input and output shafts 6, 8, the tapered roller bearing 18 pumps lubricant from the small end 19 to the large end 21. Accordingly, the tapered roller bearing 18 forms a pump for the lubricant, and is thus, configured to pump lubricant from the lubricant receiving space 20 to the first bearing 12.

[0043] The tapered roller bearing 18 is arranged in a first bearing seat 26 provided at an end 25 of the input shaft 6, and a second bearing seat 28 provided in the second gear wheel 24. The end 25 of the input shaft 6 is the end of the input shaft 6 closest to the output shaft 8. In these embodiments, the first bearing seat 26 is provided in the input shaft 6 itself. According to alternative embodiments, the first bearing seat 26 may be provided in a member attached to the end 25 of the input shaft 6.

[0044] A first lubricant path 23, indicated with a broken line in FIG. 3, extends through, or along, the second gear wheel 24, from the lubricant receiving space 20 to the small end 19 of the tapered roller bearing 18. Thus, the fluid connection between the lubricant receiving space 20 and the small end 19 of the tapered roller bearing 18 may be provided by the first lubricant path 23. In these embodiments, the first lubricant path 23 extends through the second gear wheel 24. For this purpose, the second gear wheel 24 is provided with one or more axially extending through holes 17. Additionally, or according to alternative embodiments, a splined connection 27 between the second gear wheel 24 and the output shaft 8, may be formed with missing splines and/or enlarged gaps at the top or the bottom of one or more splines.

[0045] A second lubricant path 29, indicated with a broken line in FIG. 3, extends through, or along the differential spider 14 from the large end 21 of the tapered roller bearing 18 to the first bearing 12. Thus, the fluid connection between the large end 21 of the tapered roller bearing 18 and the first bearing 12 may be provided by the second lubricant path 29. In these embodiments, the second lubricant path 29 extents along the differential spider 14. For this purpose, a splined connection 31 between the differential spider 14 and the input shaft 6, may be formed with missing splines and/or enlarged gaps at the top or the bottom of one or more splines such that lubricant may flow through the splined connection 31. Additionally, or according to alternative embodiments, the differential spider 14 may be provided with through holes extending in an axial direction in parallel with the input shaft 6, in the same manner as through the second gear wheel 24.

[0046] In this manner, the tapered roller bearing 18 pumps lubricant from the lubricant receiving space 20 via the first lubricant path 23 and the second lubricant path 29 to the first bearing 12.

[0047] According to some embodiments, the second lubricant path 29 may extend through the first bearing 12, as indicated by the short broken line 35 in FIG. 3. Thus, the tapered roller bearing 18 may pump lubricant to further parts requiring lubrication when there exists a rotational speed difference between the input and output shafts 6, 8. An axial bearing 33 supporting the first gear wheel 10 in an axial direction on the input shaft 6 may form such a further part requiring lubrication when there exists a rotational speed difference between the input shaft 6 and the output shaft 8. The axial bearing 33 may be a plain bearing, a roller bearing or a ball bearing.

[0048] In FIG. 3 the first and second lubricant paths 23, 29, 35 are indicated below the input and output shafts 6, 8. However, the first and second lubricant paths 23, 29, 35 may extend along the input and output shafts 6, 8, at various circumferential positions around the input and output shafts 6, 8, in order to permit the tapered roller bearing 21 to pump lubricant unimpededly towards the first bearing 12, and in order to provide lubricant around the circumferentially around the first bearing.

[0049] FIGS. 4a and 4b illustrate two different embodiments of parts of the axle assembly 2 of FIGS. 2 and 3. More specifically, different embodiments of the second lubricant path 29, and the components of the axle assembly 2 delimiting the second lubricant path 29 are shown in FIGS. 4a and 4b. In the following, reference is made to both of FIGS. 4a and 4b, unless specific references to one of FIGS. 4a and 4b are made. The second lubricant path 29 is schematically indicated with broken lines in FIGS. 4a and 4b.

[0050] The second lubricant path 29 comprises a first annular space 30 formed between the input shaft 6, the large end 21 of the tapered roller bearing 18, and a first axial portion 38 of the differential spider 14. The first axial portion 38 of the differential spider 14 faces in a direction towards the second gear wheel 24 and the large end 21 of the tapered roller bearing 18.

[0051] The first annular space 30 is limited in an outer radial direction by a first ring-shaped member 32. In this manner, the first annular space 30 may be mechanically sealed off. Thus, the lubricant pumped from the large end 21 of the tapered roller bearing 18 may be directed along, or through, the differential spider 14. Thus, the lubricant will flow along the second lubricant path 29. The first ring-shaped member 32 may extend in parallel with the input shaft 6. The first ring-shaped member 32 may be formed by a separate member, as shown in FIG. 4a, or alternatively may form part of the differential spider 14, as shown in FIG. 4b, or of the second gear wheel 24.

[0052] According to some embodiments, as shown in FIG. 4a, the first ring-shaped member 32 may be connected to the second gear wheel 24 and extend in an axial direction towards the first axial portion 38 of the differential spider 14.

[0053] According to some embodiments, as shown in FIG. 4b, the first ring-shaped member 32 may be connected to the differential spider 14 and extend in an axial direction towards the second gear wheel 24.

[0054] The second lubricant path 29 further comprises a second annular space 34 formed between the input shaft 6, a second axial portion 40 of the differential spider 14, and the first gear wheel 10. The second axial portion 40 of the differential spider 14 faces in a direction towards the first gear wheel 10.

[0055] The second annular space 34 is limited in an outer radial direction by a second ring-shaped member 36. In this manner, the second annular space 34 may be mechanically sealed off. Thus, the lubricant pumped from the tapered roller bearing 18 along or through the differential spider 14, may be directed to the first bearing 12 via the second annular space 34. Thus, the lubricant will flow along the second lubricant path 29. The second ring-shaped member 36 may extend in parallel with the input shaft 6. The second ring-shaped member 36 may be formed by a separate member, as shown in FIG. 4a, or alternatively may form part of the differential spider 14, or of the first gear wheel 10, as shown in FIG. 4b.

[0056] According to some embodiments, as shown in FIG. 4b, the second ring-shaped member 36 may be connected to the first gear wheel 10 and extend in an axial direction towards the second axial portion 40 of the differential spider 14.

[0057] According to some embodiments, as shown in FIG. 4a, the second ring-shaped member 36 may be connected to the differential spider 14 and extend in an axial direction towards the first gear wheel 10.

[0058] In the embodiments shown in FIG. 4b, an overlap is provided between the first ring-shaped member 32 of the differential spider 14 and the second gear wheel 24 in order to mechanically seal off the first annular space 30 in a radially outwardly direction. Similarly, an overlap is provided between the second ring-shaped member 36 of the first gear wheel 10 and the differential spider 14 in order to mechanically seal off the second annular space 34 in a radially outwardly direction.

[0059] It is to be understood that the foregoing is illustrative of various example embodiments and that the invention is defined only by the appended claims. A person skilled in the art will realize that the example embodiments may be modified, and that different features of the example embodiments may be combined to create embodiments other than those described herein, without departing from the scope of the invention, as defined by the appended claims.