Differential and vehicle transmission

Abstract

There is provided a differential comprising a ring gear (1); the shell is provided with a first split part (21) and a second split part (22) which are of the same structure, the first split part (21) and the second split part (22) are coaxial with the gear ring (1), the first split part (21) and the second split part (22) are installed together with the gear ring (1) in a detachable mode, and the first split part (21) and the second split part (22) are in spline connection with the gear ring (1) so as to achieve transmission connection. The first split part (21) and the second split part (22) enclose to form an installation space (2s); and a bevel gear set (3) housed and mounted in the mounting space (2s). Therefore, the shell high enough in precision can be obtained without additional finish machining, the shell can achieve dynamic balance in the working process of the differential mechanism, and the structure of the differential mechanism is beneficial to disassembly, assembly, torque transmission and simplification of the manufacturing and assembling process. The invention further provides a vehicle transmission comprising the differential mechanism.

Description

Differential and vehicle transmission Technical Field

[0001] The present application relates to the field of wheel differentials of vehicles, and in particular to a differential and a vehicle transmission including the differential. Background Art

[0002] In the prior art, differentials are commonly used in vehicle transmissions to transfer torque from the vehicle's transmission to the wheels and enable different wheels to rotate at different speeds when the vehicle turns. A bevel gear differential is a typical differential used in vehicle transmissions.

[0003] An existing bevel gear differential utilizes a one-piece housing. This complex structure results in complex manufacturing tools and a cumbersome molding process. Furthermore, the manufacturing process for this one-piece housing typically involves sand casting a blank followed by machining. The poor precision of sand casting can easily lead to defects such as shrinkage and cavitation, necessitating fine machining of the blank (especially in areas that mate with other components). Furthermore, specialized tools are often required to ensure the dynamic balance of the one-piece housing during differential operation.

[0004] In another existing bevel gear differential, a split housing is used. In this case, the split housing and the ring gear as the input element of the differential are fixed together in a non-detachable manner such as welding, causing the differential to be damaged during disassembly.

[0005] Summary of the Invention

[0006] This application is based on the aforementioned shortcomings of the prior art. The present application aims to provide a differential with a relatively simple structure that can be assembled and disassembled without damaging the structure. Furthermore, the differential can produce a sufficiently precise housing without requiring additional finishing, and can also achieve dynamic balancing of the housing during operation. Another object of the present application is to provide a vehicle transmission incorporating the differential.

[0007] In order to achieve the above objectives, the present application may adopt the following technical solutions.

[0008] The present application provides a differential as follows, comprising:

[0009] Ring gear;

[0010] a housing having a first split portion and a second split portion of identical structure, the first split portion and the second split portion being coaxially arranged with the ring gear, the first split portion and the second split portion being detachably mounted to the ring gear, the first split portion and the second split portion being spline-connected to the ring gear to achieve transmission connection, and the first split portion and the second split portion enclosing an installation space; and

[0011] A bevel gear set is accommodated and installed in the installation space, and the bevel gear set includes a gear shaft, a first bevel gear pair and a second bevel gear pair. The gear shaft extends along a radial direction of the ring gear and is transmission-connected to the ring gear. The two bevel gears in the first bevel gear pair are installed on the gear shaft and can rotate around the gear shaft. Each bevel gear in the second bevel gear pair is respectively engaged with the two bevel gears in the first bevel gear pair.

[0012] In an optional solution, the ring gear is formed with at least one annular groove, and the differential includes at least one snap ring, which is installed in the at least one annular groove for axially limiting the first split part and the second split part.

[0013] In another optional solution, the gear ring is formed with two mounting grooves, and the axial ends of the gear shaft are respectively inserted into the two mounting grooves, so that the gear shaft can be directly driven to rotate by the gear ring.

[0014] In another optional solution, the gear ring has a circular ring shape, and is provided with a first internal spline and a second internal spline on its inner circumferential surface, wherein the first internal spline and the second internal spline are arranged side by side at intervals in the axial direction of the gear ring.

[0015] The first split portion is provided with a first external spline, which is engaged with the first internal spline. The second split portion is provided with a second external spline, which is engaged with the second internal spline.

[0016] In another optional solution, the ring gear has a central protrusion, and the central protrusion is located between the first internal spline and the second internal spline in the axial direction.

[0017] The gear ring is formed with a first annular groove, and the differential further includes a first snap ring, which is installed in the first annular groove. The first snap ring and the central protrusion are located on both axial sides of the first external spline to axially limit the first external spline, and

[0018] The ring gear is also formed with a second annular groove, and the differential also includes a second snap ring, which is installed in the second annular groove. The second snap ring and the central protrusion are located on both axial sides of the second external spline to axially limit the second external spline.

[0019] In another optional solution, the central protrusion is formed with two mounting grooves, and the two end portions of the gear shaft are formed with mounting portions corresponding to the mounting grooves, and the mounting portions are inserted into the corresponding mounting grooves.

[0020] In another optional solution, the mounting groove is a U-shaped groove, which includes two parallel planar side walls, and the mounting portion is formed with an abutment portion that matches the shape of the two side walls and contacts each other, and the side wall and the abutment portion cooperate to achieve transmission connection.

[0021] In another optional solution, there is a symmetry plane perpendicular to the axial direction of the ring gear, and the differential as a whole has a symmetrical structure relative to the symmetry plane.

[0022] In another optional solution, the first split portion and the second split portion are processed by using the same set of fine blanking equipment.

[0023] The present application also provides a vehicle transmission as follows, comprising the differential described in any one of the above technical solutions.

[0024] By adopting the above-described technical solution, the present application provides a differential comprising a ring gear, a housing, and a bevel gear set. Typically, the ring gear receives torque from outside the differential, while the bevel gear set transmits torque to the outside of the differential. The housing comprises a first and second split portion of identical structure, coaxially arranged with the ring gear. The first and second split portions are detachably mounted to the ring gear and spline-connected to the ring gear, thereby providing a driving connection between the housing and the ring gear. Furthermore, the first and second split portions enclose an installation space within which the bevel gear set is housed. The bevel gear set comprises two meshing bevel gear pairs. The bevel gears of one bevel gear pair are mounted on a gear shaft so as to rotate with the gear shaft about the central axis of the ring gear and are also rotatable about the gear shaft. The other bevel gear pair meshes with the first bevel gear pair to transmit torque, for example, via axles to the wheels of a vehicle. The present application also provides a vehicle transmission including the above-described differential.

[0025] Thus, since the housing of the differential of the present application adopts a split structural design and the two split parts of the housing have the same structure, the two split parts can be formed by a fine stamping process, so that a housing with sufficiently high precision can be produced without additional finishing, and the mass distribution of the two split parts of the housing can be symmetrical and uniform without additional finishing, thereby achieving dynamic balance of the housing during the operation of the differential. In addition, the housing and the ring gear are installed together in a detachable manner and the two split parts are spline-connected to the ring gear, so the differential can be disassembled without damaging the structure of the housing and the ring gear, and can transmit greater torque than using welding or bolting. Furthermore, the structure of the differential of the present application is relatively simple, which is conducive to simplifying the manufacturing and assembly process. In addition, a vehicle transmission including the above-mentioned differential has the same beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG1 is a schematic cross-sectional view showing a differential according to an embodiment of the present application, in which hatching is omitted.

[0027] FIG. 2 is a schematic diagram showing the exploded structure of the differential in FIG. 1 .

[0028] FIG. 3 is a perspective schematic diagram showing a ring gear of the differential in FIG. 1 .

[0029] FIG. 4 is a perspective schematic diagram showing a first snap ring of the differential in FIG. 1 .

[0030] Explanation of the reference numerals 1 ring gear; 1c1 first annular groove; 1c2 second annular groove; 11 first internal spline; 12 second internal spline; 13 central protrusion; 13c mounting groove; 21 first split portion; 211 first external spline; 212 first tapered portion; 212h first weight-reducing hole; 213 first bearing seat; 22 second split portion; 221 second external spline; 222 second tapered portion; 222h second weight-reducing hole; 223 second bearing seat; 2s mounting space; 3 bevel gear set; 31 gear shaft; 31p mounting portion; 32a first bevel gear; 32b second bevel gear; 33a third bevel gear; 33b fourth bevel gear; 41 first retaining ring; 42 second retaining ring; 51 first bearing; 52 second bearing; P symmetry plane; A axial direction; R radial direction. DETAILED DESCRIPTION

[0031] The specific embodiments of the present application will be described in detail below in conjunction with the accompanying drawings. It should be understood that these specific descriptions are only used to teach those skilled in the art how to implement the present application, and are not intended to exhaust all possible methods of the present application, nor to limit the scope of the present application.

[0032] In this application, "transmission connection" refers to a connection between two components that can transmit torque, including direct connection and indirect connection.

[0033] In this application, unless otherwise specified, “axial direction”, “radial direction” and “circumferential direction” refer to the axial direction, radial direction and circumferential direction of the ring gear, respectively.

[0034] The structure of a differential according to an embodiment of the present application will be described below with reference to the accompanying drawings.

[0035] As shown in Figures 1 and 2, a differential according to an embodiment of the present application includes a ring gear 1, a housing (a first sub-body 21 and a second sub-body 22), a bevel gear set 3, two retaining rings 41, 42 and two bearings 51, 52 assembled together. As shown in Figure 1, the differential as a whole has a structure that is symmetrical relative to a symmetry plane P (indicated by a single dotted line in Figure 1), and the symmetry plane P is perpendicular to the axial direction A. Symmetry here means that the overall structural layout of the differential is roughly symmetrical, but it does not necessarily have to be completely precisely symmetrical. For example, in this embodiment, the outer teeth of the ring gear 1 can have an asymmetric shape relative to the symmetry plane P. As an example, the ring gear 1 shown in Figure 2 is a helical gear.

[0036] In this embodiment, ring gear 1 can be drivingly coupled to the output gear of an output shaft of a vehicle's transmission, for example, allowing torque from outside the differential to be transmitted to ring gear 1. Here, ring gear 1 can be, for example, an external ring gear. As shown in Figure 1 , ring gear 1 has a circular ring shape and is coaxially arranged with the housing and the second bevel gear pair 33a, 33b of bevel gear set 3.

[0037] As shown in Figures 1 to 3, the inner circumferential surface of the ring gear 1 is provided with a first internal spline 11, a second internal spline 12, and a central protrusion 13. The first internal spline 11, the second internal spline 12, and the central protrusion 13 are arranged side by side in the axial direction A. The central protrusion 13 is located between the first internal spline 11 and the second internal spline 12 in the axial direction A, so that the first internal spline 11 and the second internal spline 12 are arranged in the axial direction A with the central protrusion 13 interposed therebetween.

[0038] As shown in Figures 1 to 3, the ring gear 1 also has a first annular groove 1c1 and a second annular groove 1c2. The first annular groove 1c1 is located on the opposite side of the first internal spline 11 from the central projection 13 (the left side in Figure 1) and is used to insert and install the first retaining ring 41. The second annular groove 1c2 is located on the opposite side of the second internal spline 12 from the central projection 13 (the right side in Figure 1) and is used to insert and install the second retaining ring 42.

[0039] As shown in Figures 2 and 3, the central protrusion 13 is formed with two mounting grooves 13c corresponding to the mounting portion 31p of the gear shaft 31 of the bevel gear set 3. These two mounting grooves 13c are separated by a central angle of 180 degrees and have the same shape. As shown in Figure 3, each mounting groove 13c is a U-shaped groove with a square cross-section corresponding to the mounting portion 31p of the gear shaft 31. The circumferential sidewalls of the mounting grooves 13c are formed as parallel planes, designed to abut against the mounting portion 31p of the gear shaft 31.

[0040] In this embodiment, as shown in Figures 1 and 2 , the housing is a rotating body having a central axis. The cross-section of the rotating body at any axial position is annular, and the housing as a whole is capable of rotating about the central axis. Specifically, the housing includes a first split portion 21 and a second split portion 22 of identical structure. The first and second split portions 21, 22 are coaxially arranged with the ring gear 1 and symmetrically arranged relative to the symmetry plane P. The first and second split portions 21, 22 are removably mounted to the ring gear 1, providing a transmission connection between the housing and the ring gear 1. Furthermore, the first and second split portions 21, 22 enclose an installation space 2s.

[0041] As shown in Figures 1 and 2, the first split portion 21 includes an integrally formed first external spline 211, a first tapered portion 212, and a first bearing seat 213. The first external spline 211 meshes with the first internal spline 11 of the ring gear 1. The large diameter end of the first tapered portion 212 is connected to the root of the first external spline 211, and the small diameter end of the first tapered portion 212 is connected to the first bearing seat 213. The second split portion 22 includes an integrally formed second external spline 221, a second tapered portion 222, and a second bearing seat 223. The second external spline 221 meshes with the second internal spline 12 of the ring gear 1. The large diameter end of the second tapered portion 222 is connected to the root of the second external spline 221, and the small diameter end of the second tapered portion 222 is connected to the second bearing seat 223. Furthermore, to reduce the weight of the housing, the first tapered portion 212 is formed with a plurality of first weight-reducing holes 212h spaced apart in the circumferential direction, and the second tapered portion 222 is formed with a plurality of second weight-reducing holes 222h spaced apart in the circumferential direction. Because the first and second sub-sections 21, 22 have identical structures, they can be precision-blanked using the same fine-blanking apparatus. This eliminates the need for additional finishing work on the first and second sub-sections 21, 22 to achieve a sufficiently precise housing and maintain dynamic balance during differential operation.

[0042] In this embodiment, as shown in Figures 1 and 2, the bevel gear set 3 is housed and mounted in the mounting space 2s formed by the first split portion 21 and the second split portion 22. The bevel gear set 3 includes a gear shaft 31, a first bevel gear pair (a first bevel gear 32a and a second bevel gear 32b), and a second bevel gear pair (a third bevel gear 33a and a fourth bevel gear 33b).

[0043] As shown in Figure 1, the gear shaft 31 extends along a radial direction R of the ring gear 1 and is drivingly coupled to the ring gear 1. Specifically, the gear shaft 31 is removably inserted into the mounting groove 13c of the central protrusion 13 of the ring gear 1 along the radial direction R. The gear shaft 31 is used to mount the first bevel gear pair, allowing the first bevel gear 32a and the second bevel gear 32b of the first bevel gear pair to rotate with the gear shaft 31 and the housing as a whole. The first bevel gear 32a and the second bevel gear 32b can also rotate about the gear shaft 31. Furthermore, mounting portions 31p are formed at each end of the gear shaft 31 to correspond to the mounting grooves 13c. The mounting portions 31p are inserted into the corresponding mounting grooves 13c. The mounting portions 31p may be formed with abutment portions that conform to and contact the two circumferential sidewalls of the mounting groove 13c. The two circumferential sidewalls cooperate with the abutment portions to achieve a driving connection between the ring gear 2 and the gear shaft 31. To ensure that, after the mounting portion 31p engages with the mounting groove 13c, the gear shaft 31 rotates with the ring gear 1 without rotating relative to the ring gear 1, the mounting portion 31p may have a square cross-section. The engagement of the mounting groove 13c of the ring gear 1 with the mounting portion 31p not only increases the contact area between the gear shaft 31 and the ring gear 1, facilitating the transmission of high torque, but also prevents relative rotation between the gear shaft 31 and the ring gear 1.

[0044] As shown in Figures 1 and 2, the first bevel gear 32a and the second bevel gear 32b of the first bevel gear pair are mounted on the gear shaft 31 and can rotate about the gear shaft 31. The third bevel gear 33a of the second bevel gear pair meshes with both the first bevel gear 32a and the second bevel gear 32b of the first bevel gear pair, and the fourth bevel gear 33b of the second bevel gear pair meshes with both the first bevel gear 32a and the second bevel gear 32b of the first bevel gear pair. Both the third bevel gear 33a and the fourth bevel gear 33b have internal splines that mate with the external splines of the half shafts, allowing the differential to output torque to the half shafts via the bevel gear set 3.

[0045] In this embodiment, as shown in Figures 1, 2, and 4, the first and second snap rings 41, 42 have the same structure and are both C-shaped. The first snap ring 41 is mounted in the first annular groove 1c1 and protrudes radially inward relative to the first annular groove 1c1. The first snap ring 41 and the central protrusion 13 are located on either side of the first external spline 211 in the axial direction to axially limit the first external spline 211. The second snap ring 42 is mounted in the second annular groove 1c2 and protrudes radially inward relative to the second annular groove 1c2. The second snap ring 42 and the central protrusion 13 are located on either side of the second external spline 221 in the axial direction to axially limit the second external spline 221.

[0046] In this embodiment, as shown in Figures 1 and 2 , the first bearing 51 and the second bearing 52 can both be single-row tapered roller bearings. The inner ring of the first bearing 51 fits within the first bearing seat 213, while the inner ring of the second bearing 52 fits within the second bearing seat 223. The two bearings 51 and 52 are mounted to the housing with their inner rings fixed to the axial ends of the housing. The two bearings 51 and 52 support the differential housing to enable normal rotation.

[0047] The above is a detailed description of the specific technical solutions of the present application, but the present application is not limited to the above technical solutions, and supplementary explanations are given below.

[0048] i. The aforementioned split housing has a relatively simple structure and can be manufactured not only using fine-blanking but also through precision forging and other methods, thereby improving the housing's machining accuracy and component strength. Because the first and second split portions 21, 22 have identical structures and are symmetrically arranged, the housing formed by the first and second split portions 21, 22 can achieve dynamic balance during transmission operation even without additional processing. Furthermore, when fine-blanking is used, the first and second split portions 21, 22 can be manufactured using the same set of fine-blanking equipment, significantly reducing manufacturing costs.

[0049] ii. In the above embodiment, since the housing and the ring gear 1 are connected by splines, and the structure of the ring gear 1 itself (the central protrusion 13) and the retaining rings 41 and 42 are used to cooperate to axially limit the first split portion 21 and the second split portion 22, the above structure not only makes the structure of the differential relatively simple, but also allows it to be disassembled and assembled without damaging the structure of the differential, thereby reducing the maintenance cost of the differential.

[0050] It is understood that in an alternative solution, the internal splines of the ring gear 1 can extend continuously along the axial direction A of the ring gear 1 (rather than forming a discontinuous structure as in the above embodiment), and the central protrusion 13 of the ring gear 1 can be omitted. In this case, the first and second split parts 21, 22 of the housing can abut against each other in the axial direction A, and the first and second split parts 21, 22 can be axially limited by the retaining rings 41, 42, thereby achieving the same effect as the above embodiment.

[0051] It is understood that in another optional solution, the internal splines of the ring gear 1 can extend continuously along the axial direction A of the ring gear 1 (rather than forming a discontinuous structure as in the above embodiment), and the central protrusion 13 of the ring gear 1 can be omitted. Moreover, one of the retaining rings 41 and 42 can be formed integrally with the ring gear 1, that is, the ring gear 1 is formed with a limiting protrusion for axial limiting, and the limiting protrusion cooperates with the other of the retaining rings 41 and 42 to axially limit the first and second sub-parts 21 and 22, thereby achieving the same effect as the above embodiment.

[0052] iii. As can be appreciated, compared to a case where separate housing parts are connected by multiple bolts, this eliminates the need for multiple bolts, reduces the number of components, and speeds up assembly. This reduces or eliminates the radial space required for housing mounting bolts, miniaturizing the differential, reducing material costs, and facilitating lightweight installation in transmissions and other applications. Compared to bolted or welded connections, spline connections offer greater strength, helping the differential meet greater torque transmission requirements.

[0053] iv. By matching the mounting portion 31p of the gear shaft 31 with the mounting groove 13c of the ring gear 1, the gear shaft 31 and the ring gear 1 are directly connected in a transmission manner, without passing through the housing. This significantly reduces the load on the housing and the strength requirements of the housing. This allows the differential housing to serve only as a support, allowing for a smaller wall thickness, reducing its size and weight.

[0054] v. It can be understood that after all components of the differential are installed in place, the first split portion 21 and the second split portion 22 can axially limit the gear shaft 31.

[0055] vi. The present application also provides a transmission for a vehicle, which may include the differential described in the above specific embodiments, and the power source of the vehicle may transmit torque to the wheels via the differential.

Claims

1. A differential comprising: Ring gear (1); A housing, comprising a first split portion (21) and a second split portion (22) of identical structure, the first split portion (21) and the second split portion (22) being coaxially arranged with the gear ring (1), the first split portion (21) and the second split portion (22) being mounted together with the gear ring (1) in a detachable manner, the first split portion (21) and the second split portion (22) being respectively spline-connected with the gear ring (1) to achieve transmission connection, and the first split portion (21) and the second split portion (22) enclosing and forming an installation space (2s); as well as A bevel gear set (3) is accommodated and installed in the installation space (2s), the bevel gear set (3) comprising a gear shaft (31), a first bevel gear pair (32a, 32b) and a second bevel gear pair (33a, 33b), the gear shaft (31) extending along a radial direction (R) of the gear ring (1) and being transmission-connected to the gear ring (1), two bevel gears in the first bevel gear pair (32a, 32b) being installed on the gear shaft (31) and being able to rotate around the gear shaft (31), and each bevel gear in the second bevel gear pair (33a, 33b) being respectively meshed with two bevel gears in the first bevel gear pair (32a, 32b).

2. The differential according to claim 1, characterized in that: The gear ring (1) is formed with at least one annular groove, and the differential comprises at least one snap ring, which is mounted to the at least one annular groove and is used for axially limiting the first split part (21) and the second split part (22).

3. The differential according to claim 1 or 2, characterized in that: The gear ring (1) is formed with two mounting grooves (13c), and the axial ends of the gear shaft (31) are respectively inserted into the two mounting grooves (13c), so that the gear ring (1) can directly drive the gear shaft (31) to rotate.

4. The differential according to any one of claims 1 to 3, characterized in that: The gear ring (1) has a circular ring shape, and is provided with a first internal spline (11) and a second internal spline (12) on its inner circumferential surface, wherein the first internal spline (11) and the second internal spline (12) are arranged side by side at intervals in the axial direction (A) of the gear ring (1). The first split part (21) is provided with a first external spline (211), and the first external spline (211) and the first internal spline (11) are meshed with each other. The second split part (22) is provided with a second external spline (221), and the second external spline (221) and the second internal spline (12) are meshed with each other.

5. The differential according to claim 4, characterized in that: The gear ring (1) has a central protrusion (13), and the central protrusion (13) is located between the first internal spline (11) and the second internal spline (12) in the axial direction (A). The gear ring (1) is formed with a first annular groove (1c1), the differential further comprises a first snap ring (41), the first snap ring (41) is installed in the first annular groove (1c1), the first snap ring (41) and the central protrusion (13) are located on both axial sides of the first external spline (211) to axially limit the first external spline (211), and The gear ring (1) is also formed with a second annular groove (1c2), and the differential also includes a second snap ring (42), the second snap ring (42) is installed in the second annular groove (1c2), and the second snap ring (42) and the central protrusion (13) are located on both axial sides of the second external spline (221) to axially limit the second external spline (221).

6. The differential according to claim 5, characterized in that: The central protrusion (13) is formed with two mounting grooves (13c), and the two ends of the gear shaft (31) are formed with mounting parts (31p) corresponding to the mounting grooves (13c), and the mounting parts (31p) are inserted into the corresponding mounting grooves (13c).

7. The differential according to claim 6, characterized in that: The mounting groove (13c) is a U-shaped groove, comprising two parallel and planar side walls, the mounting portion (31p) is formed with abutment portions that match the shape of the two side walls and contact each other, and the side walls cooperate with the abutment portions to achieve transmission connection.

8. The differential according to any one of claims 1 to 7, characterized in that: There is a symmetry plane (P) perpendicular to the axial direction (A) of the ring gear (1), and the differential as a whole has a symmetrical structure relative to the symmetry plane (P).

9. The differential according to any one of claims 1 to 8, characterized in that: The first split part (21) and the second split part (22) are processed by using the same set of fine blanking equipment.

10. A vehicle transmission comprising the differential according to any one of claims 1 to 9.

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