CN117677519A - Differential mechanism - Google Patents

Abstract

There is provided a differential comprising: an input gear (5) capable of receiving torque from the outside of the differential; a planetary wheel shaft (2) which extends in one radial direction (R) of the input gear (5) and is in direct drive connection with the input gear (5); a planetary gear (3) that is mounted to the planetary wheel shaft (2) and is rotatable around the planetary wheel shaft (2); and an output gear (4) which meshes with the planetary gear (3) and can transmit torque to the outside of the differential. In this way, the problem of excessive geometry and heavy weight of the housing due to the need for torque transfer through the differential housing is avoided, the number of bolts used for fixing between the input gear and the housing is reduced, the corresponding costs are reduced and the problem of mounting the bolts is eliminated.

Description

Differential Technical field

The present application relates to the field of vehicle wheel differentials, and specifically to a differential.

Background technique

In the prior art, a differential is usually used in a vehicle's transmission mechanism to transmit torque from the vehicle's transmission to the wheels and enable different wheels to rotate at different rotational speeds when the vehicle turns.

Figure 1 shows a schematic cross-sectional view of a differential. As shown in FIG. 1 , the differential includes a housing 10 , a planetary gear shaft 20 , a pin 30 , a planetary gear 40 , an output gear 50 , an input gear 60 , a bearing 70 and a bolt 80 .

Specifically, the housing 10 is a rotating body having a central axis. The cross-sectional shape of the rotating body at any location is a substantially circular ring shape, and the housing 10 as a whole can rotate around the central axis. An installation space S is formed inside the housing 10 , and a gear transmission mechanism composed of the planetary gear 40 and the output gear 50 is accommodated in the installation space S.

The two planetary gears 40 and the two output gears 50 constitute a gear transmission mechanism. The output gear 50 is connected to a half shaft passing through a through hole extending in the axial direction A of the housing 10 . Each planet gear 40 meshes with two output gears 50 . The two planetary gears 40 are installed on the same planetary gear shaft 20 that is fixed to the housing 10 , so that the two planetary gears 40 can rotate with the housing 10 as a whole and also rotate around the planetary shaft 20 . The planetary shaft 20 is fixed to the housing 10 by a pin 30 passing through one end of the planetary shaft 20 in the length direction.

The input gear 60 is mounted and fixed to the housing 10 via a large number (for example, more than 10) bolts 80 . In this way, the input gear 60 can transmit torque from the outside of the differential (eg, the output shaft of the transmission) to the housing 10 via the bolt.

The inner ring of the bearing 70 is fixedly mounted on both axial ends of the housing 10 in an interference fit manner. In this way, when the outer ring of the bearing 70 is supported by, for example, the housing of the transmission, the bearing 70 can well support the housing 10 so that the housing 10 can rotate stably.

In this way, the torque from the outside will be sequentially transmitted to the axle shaft of the vehicle via the input gear 60, the housing 10, the planetary gear shaft 20, the planetary gear 40 and the output gear 50, and finally to the wheels of the vehicle.

However, the differential having the above structure has the following drawbacks. Since the torque from the outside will pass through the housing 10, the load that the housing 10 needs to bear will be quite large, so the housing 10, which is usually made of cast iron, needs to have a large geometric size and a heavy weight. In addition, since the bolt 80 cannot withstand the shear force, the torque transmission between the input gear 60 and the housing 10 depends on the friction torque between the two, and the size of this friction torque depends on the predetermined strength of the bolt 80 . The size of the tightening force, therefore, in order to meet the requirements, more than 10 bolts 80 are usually provided to fix the input gear 60 to the housing 10, and the position accuracy of the threaded holes of the mounting bolts 80 needs to be strictly controlled, and special tools need to be used to accurately Control the tightening torque of bolt 80.

Contents of the invention

This application was made based on the above-mentioned shortcomings of the prior art. The purpose of the invention of the present application is to provide a new type of differential that can avoid the problems of excessive geometric size and heavy weight of the housing due to the torque transmission path that needs to be transmitted from the input gear to the housing, and can Alleviates the cost and installation issues associated with the excessive number of bolts used to connect the input gear to the housing.

In order to achieve the above-mentioned object of the invention, this application may adopt the following technical solutions.

This application provides a differential as follows, including:

an input gear capable of receiving torque from outside the differential;

A planetary shaft extending along one radial direction of the input gear, the planetary shaft being directly drivingly coupled with the input gear so that torque can be directly transmitted between the input gear and the planetary shaft;

A planetary gear mounted on the planetary axle and capable of rotating around the planetary axle; and

An output gear meshes with the planetary gears and is capable of transmitting torque to the outside of the differential.

In an optional solution, mounting portions are formed at both ends of the planetary gear shaft, the input gear is formed with a mounting groove corresponding to the mounting portion, and the mounting portion is inserted into the corresponding mounting groove. , so that the planet wheel shaft can rotate together with the input gear.

In another optional solution, the outline of the installation groove is U-shaped, and the installation groove includes two planar side walls parallel to each other and an arc-shaped bottom wall connecting the two side walls, and the The mounting portion includes a flat portion in contact with the two flat side walls, and the bottom wall restricts the planet wheel shaft from moving in its axial direction.

In another optional solution, the cross section of the mounting portion is formed into a square shape.

In another optional solution, the differential further includes a housing, the housing is coaxially fixed with the input gear, an installation space is formed inside the housing, and the planetary gear and the output gear are both stored and installed in the installation space, and the planet wheel shaft passes through the housing and is relatively fixed to the housing.

In another optional solution, the housing includes a main body portion and a peripheral portion fixed to each other, the installation space is located inside the main body portion, and the peripheral portion protrudes from the main body portion toward the radially outer side. ,

The planetary shaft extends through the installation space along the radial direction, and both ends of the planetary shaft protrude to the outside of the main body.

In another optional solution, the input gear is sleeved on the outside of the main body part, and the input gear is fixed to the peripheral part.

In another optional solution, the differential further includes a plurality of bolts, the input gear and the peripheral portion abut in the axial direction of the input gear, and are connected to each other through the plurality of bolts. Together, the number of bolts is no more than six.

In another optional solution, the main body part is formed with weight-reducing holes.

In another optional solution, both the planetary gear and the output gear are bevel gears.

By adopting the above technical solution, the present application provides a new type of differential, which includes an input gear, a planetary shaft, a planetary gear and an output gear. The input gear is capable of receiving torque from the outside. The planetary shaft extends along a radial direction of the input gear, and the planetary shaft is directly connected to the input gear, so that torque can be directly transmitted between the input gear and the planetary shaft. The planet gear is mounted on the planet shaft and can rotate around the planet shaft. The output gear meshes with the planetary gear and can transmit torque to the outside.

In this way, due to the direct transmission connection between the input gear and the planetary shaft, the problem of excessively large geometric size and heavy weight of the differential housing due to the need for torque transmission through the differential housing is avoided. In addition, for the same reason as above, it is not necessary to use the friction torque between the input gear and the differential housing to achieve torque transmission, so the number of bolts for fixing the input gear and the housing can be significantly reduced, and it is possible to The corresponding costs are reduced and the bolt installation problems described in the background art are eliminated.

Description of drawings

FIG. 1 is a schematic cross-sectional view showing a conventional differential.

FIG. 2A is a schematic structural diagram showing a differential according to an embodiment of the present application.

FIG. 2B is a schematic cross-sectional view showing the differential in FIG. 2A.

Explanation of reference signs

10 housing 20 planetary shaft 30 pin 40 planetary gear 50 output gear 60 input gear 70 bearing 80 bolt

1 Housing 11 Main body 11h Weight reduction hole 12 Peripheral part 2 Planetary shaft 21 Mounting part 3 Planetary gear 4 Output gear 5 Input gear 5c Mounting groove 6 Bearing 7 Bolt

SInstallation space Aaxial direction Rradial direction.

Detailed ways

Specific embodiments of the present application will be described in detail below with reference to 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 ways of the present application, nor are they intended to limit the scope of the present application.

In this application, "transmission connection" refers to the connection between two components that can transmit torque; "direct transmission connection" refers to the connection between two components that can directly transmit torque without going through other components.

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 input gear respectively.

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

As shown in Figures 2A and 2B, a differential according to an embodiment of the present application includes a housing 1, a planetary shaft 2, two planetary gears 3, two output gears 4, an input gear 5, and two bearings 6 and four bolts 7.

In this embodiment, the housing 1 is a rotating body with a central axis. The cross-sectional shape of the rotating body at any axial position is generally annular. The housing 1 as a whole can rotate around the central axis. The housing 1 includes a main body part 11 and a peripheral part 12 .

The radial size of the main body portion 11 first gradually increases and then gradually decreases from one axial side (right side in FIG. 2B ) toward the other axial side (left side in FIG. 2B ). An installation space S is formed inside the main body 11 , and a gear transmission mechanism composed of the planetary gear 3 and the output gear 4 is accommodated in the installation space S. A mounting hole for inserting the planet wheel shaft 2 is formed in the axial center of the housing 1 . The two mounting holes extend along the same radial direction R and penetrate the housing 1 . In addition, two axial through holes penetrating the housing 1 in the axial direction A are also formed at both axial ends of the main body 11. Each axial through hole is used for inserting a half shaft of the vehicle, so that each half shaft can It is connected with the corresponding output gear 4 of the differential to realize the transmission connection.

The peripheral portion 12 and the main body portion 11 are fixed to each other. The peripheral portion 12 protrudes radially outward from the main body portion 11 . The peripheral portion 12 is also formed with mounting holes spaced apart in the circumferential direction for mounting the bolts 7 .

In this embodiment, the planetary shaft 2 is detachably inserted into the mounting hole of the housing 1 along the radial direction R of the housing 1 and passes through the housing 1 . The planetary gear shaft 2 is for the planetary gear 3 to be installed, so that the planetary gear 3 can rotate together with the planetary gear shaft 2 and the housing 1 as a whole, and at the same time, the planetary gear 3 can also rotate around the planetary gear shaft 2 . When the planetary shaft 2 is inserted into the mounting hole of the housing 1 , both ends of the planetary shaft 2 protrude from the main body 11 . Both ends of the planetary shaft 2 are formed with mounting portions 21 that engage with the mounting grooves 5 c of the input gear 5 . Furthermore, in order to allow the planetary shaft 2 to rotate together with the input gear 5 without causing relative rotation with respect to the input gear 5 after the mounting portion 21 is engaged with the mounting groove 5c, the cross section of the mounting portion 21 is formed into a square shape.

In this embodiment, as mentioned above, the two planetary gears 3 and the two output gears 4 constitute a gear transmission mechanism. Each planet gear 3 meshes with two output gears 4 . In other words, each output gear 4 meshes with two planetary gears 3 . The centerline axis of each output gear 4 is consistent with the central axis of the housing 1, and each output gear 4 is directly connected to the half shaft passing through the axial through hole of the housing 1, thereby realizing a transmission connection, allowing the differential to pass through the output gear 4 outputs torque to the corresponding half shaft. The two planetary gears 3 are respectively rotatably installed on the planetary gear shaft 2 , so that the two planetary gears 3 can rotate integrally with the housing 1 and the planetary gear shaft 2 and also rotate around the planetary gear shaft 2 . In this embodiment, the two planetary gears 3 and the two output gears 4 are bevel gears.

In the embodiment, the input gear 5 is coaxially arranged with the housing 1 . Specifically, the input gear 5 is mounted on the outside of the main body portion 11 of the housing 1 and is fixedly installed on the peripheral portion 12 of the housing 1 via four bolts 7 . The input gear 5 may, for example, be drivingly coupled with an output shaft of a vehicle's transmission (more specifically, may be an output gear on the output shaft) so that torque from outside the differential (eg, the transmission) can be transmitted to the input gear 5 . Furthermore, two mounting grooves 5 c corresponding to the mounting portions 21 of the planetary gear shaft 2 are formed on the inner peripheral portion of the input gear 5 . The two mounting grooves 5c are separated by a central angle of 180 degrees and have the same shape. The two mounting grooves 5 c correspond to the mounting portion 21 of the planetary shaft 2 . In this embodiment, as shown in FIG. 2A , each mounting groove 5c includes a square groove portion corresponding to the mounting portion 21 of the planet wheel shaft 2 (including two plane side walls parallel to each other) and a square groove portion connected to the square groove portion. The semicircular groove portion (including the arc-shaped bottom wall connecting the two side walls) makes the outline of the mounting groove 5c U-shaped. This shape of the mounting groove 5c is conducive to machining. In addition, the square groove portion and the mounting portion 21 cooperate with each other. On the one hand, the contact area between the input gear 5 and the planetary shaft 2 is large enough, which is conducive to transmitting larger torque; on the other hand, it can prevent the planetary shaft 2 from interacting with the input Gear 5 produces relative rotation. Further, the mounting portion 21 includes a flat portion in contact with two flat side walls, and the arc-shaped bottom wall restricts the planetary shaft 2 from moving along its axial direction, so that the mounting portion 21 of the planetary shaft 2 does not enter the semicircular shape. In the groove portion, the planetary gear shaft 2 is prevented from moving relative to the output gear 4 in its axial direction.

In this embodiment, two bearings 6 are installed on the housing 1 with their inner rings fixed to the axial ends of the housing 1 . The two bearings 6 are used to ensure that the housing 1 is relative to the supporting differential. The transmission housing 1 of the machine rotates normally.

By adopting the above solution, the following effects can be achieved.

i. By fixing the input gear 5 to the housing 1, the planetary shaft 2 passing through the housing 1, and the mounting portion 21 of the planetary shaft 2 matching the mounting groove 5c of the input gear 5, the planetary shaft 2 can be connected to the input gear 5 and the housing. The body 1 is relatively fixed, so the pin 30 described in the background art is omitted, thereby simplifying the structure and saving costs.

ii. By matching the mounting portion 21 of the planetary shaft 2 with the mounting groove 5c of the input gear 5, the planetary shaft 2 and the input gear 5 are directly connected without passing through the housing 1. Therefore, the load that the housing 1 needs to bear will be very small. , thus the strength requirements for the housing 1 are very small. In this way, the housing 1 of the differential only plays a supporting role, and can reduce the volume and weight (for example, reduce the wall thickness of the housing 1) compared with the housing 10 described in the background art.

iii. As mentioned above, since the housing 1 no longer needs to transmit torque, there is no need to use a large number of bolts 7 to fix the input gear 5 to the housing 1 and there is no need to apply a large tightening torque to the input gear 5, This can correspondingly reduce the number of bolts 7 , reduce costs, and simplify the installation process of the bolts 7 , thereby avoiding the installation problems involved in the background art. When the input gear 5 is mounted to the peripheral portion 12 of the housing 1 , the joint surface between the input gear 5 and the peripheral portion 12 can be positioned at approximately the axial center of the housing 1 , so that no interference is caused to the housing 1 It has a negative impact on the strength, and it is easy to adjust the axial position of the input gear 5, improving the flexibility of the structural layout.

In addition, the following additional explanations are provided.

i. Although it is described in the above specific embodiment that the differential according to the present application has one planetary gear shaft 2 and two corresponding planetary gears 3, the present application is not limited thereto. The differential according to the present application may have a plurality of planetary gears and planetary gears 3 corresponding to respective planetary gear axles.

ii. In order to further reduce the weight of the housing 1, as shown in Figure 2B, weight reduction holes 11h can also be formed on both sides of the main body 11 of the housing 1. This weight reduction hole 11h can also be used to reduce various components in the differential. Gear lubrication, etc.

iii. In the above specific embodiments, it is explained that the cross-section of the mounting part 21 is formed into a square shape. The square shape includes a shape with four straight sides, and also includes a straight line on two sides matching the mounting groove 5c and an arc on the other two sides. shape.

iv. It can be understood that the planetary shaft 2 is inserted through the corresponding hole of the housing 1, and the shape of the planetary shaft 2 matches the corresponding hole of the housing 1, so that the planetary shaft 2 will not shake after being installed in the housing 1. . In addition, an appropriate fitting method may be adopted as needed between the corresponding holes of the planet wheel shaft 2 and the housing 1 , for example, a transition fit may be adopted.

v. It can be understood that the number of bolts 7 used to fix the input gear 5 to the housing 1 is described in the above specific embodiment as four, but the application is not limited thereto. An appropriate number can be selected as needed. In an optional solution, the number of bolts 7 is no more than six.

Claims (10)

A differential including: an input gear (5) capable of receiving torque from outside the differential; A planetary shaft (2) extends along a radial direction (R) of the input gear (5). The planetary shaft (2) is directly drivingly coupled with the input gear (5), so that when the input gear (5) Torque can be directly transmitted between the planet wheel shaft (2) and the planet wheel shaft (2); A planetary gear (3), which is mounted on the planetary shaft (2) and can rotate around the planetary shaft (2); and An output gear (4) meshes with the planetary gear (3) and can transmit torque to the outside of the differential. The differential according to claim 1, characterized in that mounting parts (21) are formed at both ends of the planetary shaft (2), and the input gear (5) is formed with a mounting part (21). ) corresponding mounting slot (5c), and the mounting portion (21) is inserted into the corresponding mounting slot (5c), so that the planet wheel shaft (2) can rotate together with the input gear (5). The differential according to claim 2, characterized in that the installation groove (5c) has a U-shaped outline, and the installation groove (5c) includes two plane side walls parallel to each other and connects the two planes. The arc-shaped bottom wall of the side wall, the mounting portion (21) includes a planar portion in contact with the two planar side walls, and the bottom wall restricts the axial movement of the planet wheel shaft (2) along its axial direction. The differential according to claim 2 or 3, characterized in that the cross section of the mounting portion (21) is formed in a square shape. The differential according to any one of claims 1 to 4, characterized in that the differential further includes a housing (1), the housing (1) is the same as the input gear (5). The casing (1) is axially fixed together, and an installation space (S) is formed inside the housing (1). The planetary gear (3) and the output gear (4) are both stored and installed in the installation space (S). , the planet wheel shaft (2) passes through the housing (1) and is relatively fixed to the housing (1). The differential of claim 5, wherein the housing (1) includes a main body portion (11) and a peripheral portion (12) fixed to each other, and the installation space (S) is located in the main body portion. Inside (11), the peripheral portion (12) protrudes toward the radially outer side from the main body portion (11), The planetary shaft (2) extends through the installation space (S) along the radial direction (R), and both ends of the planetary shaft (2) extend to the main body (11) external. The differential according to claim 6, characterized in that the input gear (5) is sleeved on the outside of the main body part (11), and the input gear (5) is fixed to the peripheral part (12) . The differential according to claim 7, characterized in that the differential further includes a plurality of bolts (7), the input gear (5) and the peripheral portion (12) are connected to the input gear (5). 5) are abutted in the axial direction (A) and connected together by the plurality of bolts (7), the number of the plurality of bolts (7) is not more than six. The differential according to any one of claims 6 to 8, characterized in that the main body part (11) is formed with a weight reduction hole (11h). The differential according to any one of claims 1 to 9, characterized in that both the planetary gear (3) and the output gear (4) are bevel gears.