Differential device and motor vehicle

Abstract

A differential device and a motor vehicle. The differential device is used for separately transmitting driving torque from a driving device to two wheels (1) located at two axial ends of a vehicle axle. The differential device comprises two one-way clutches (3) and a differential device input end used for receiving driving torque from the driving device. Each of the two one-way clutches (3) comprises a clutch input end (31) and a clutch output end (32), the clutch input ends (31) of the two one-way clutches (3) being all in torsion-resistant connection with the differential device input end, and the clutch output end (32) of each one-way clutch (3) being used for torsion-resistant connection with a corresponding one of the corresponding wheels (1), such that the differential device can perform one-way torque transmission to the two wheels (1) separately.

Description

Differential device and motor vehicle Technical Field

[0001] The present invention relates to the technical field of vehicles, and in particular to a novel differential device and a motor vehicle. Background Art

[0002] Motor vehicles typically include multiple wheel sets, each consisting of two wheels mounted at either end of an axle. The driving force from the engine is first transmitted to the axle, and then transmitted to the two wheels via the axle. When the vehicle is traveling in an ideal straight line, the rotational speeds of the two wheels in each wheel set are the same; however, when the vehicle turns or deviates from a straight line due to road or environmental conditions, the rotational speeds of the two wheels in each wheel set will differ, so a differential is required on the axle. The driving torque from the drive unit is transmitted to the wheels at both ends of the axle via the differential, which balances the speed differences between the wheels on both sides. In the prior art, the differential includes components such as planetary gears, planetary gear carriers, and half-axle gears. Its structure is complex, resulting in high weight and cost, and it requires a large space.

[0003] Furthermore, four-wheel drive vehicles can switch between four-wheel drive and two-wheel drive. One wheelset is configured as an auxiliary drive wheelset, which needs to be disconnected from the drive unit in two-wheel drive mode to reduce electromagnetic and mechanical losses. To achieve this, a disconnect device is required between the auxiliary drive wheelset and the drive unit. This disconnect device requires additional space and is costly.

[0004] Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to provide an improved differential device and a motor vehicle.

[0006] The above technical problems are solved by a differential device according to the present invention. The differential device is used to transmit driving torque from a drive unit to two wheels located at opposite axial ends of an axle. The differential device includes two one-way clutches and a differential device input for receiving the driving torque from the drive unit. Each of the two one-way clutches includes a clutch input and a clutch output. The clutch inputs of the two one-way clutches are simultaneously torsionally connected to the differential device input, and the clutch output of each one-way clutch is torsionally connected to a corresponding one of the two wheels, enabling the differential device to transmit torque in one direction to each of the two wheels. Because two one-way clutches are used to connect the two wheels, torque can only be transmitted in one direction to the two wheels, and the speed of each wheel is allowed to exceed the speed of the input torque of the one-way clutch. Therefore, when the vehicle is turning or traveling non-straight, the corresponding one-way clutch can disconnect torque transmission between the wheel with the higher required speed (the outer wheel) and the differential device input, thereby generating a speed difference between the two wheels on either side of the same axle that is suitable for the driving conditions.

[0007] According to a preferred embodiment of the present invention, the two one-way clutches can be coaxially arranged. The two one-way clutches can especially be coaxially arranged with the two wheels on the axle, thereby realizing simple transmission connection and layout.

[0008] According to another preferred embodiment of the present invention, the input end of the differential device may be located between the two one-way clutches in the axial direction, thereby facilitating transmission connection between the input end of the differential device and the two one-way clutches respectively.

[0009] According to another preferred embodiment of the present invention, the differential device may further include an input gear as the differential input end, the input gear being coaxially arranged with the two one-way clutches, so that the differential device input end can be transmission-connected to the drive device via a gear mechanism.

[0010] According to another preferred embodiment of the present invention, the differential device may further include a connecting shaft coaxially arranged with the two one-way clutches, with both axial ends of the connecting shaft coaxially and torsionally connected to the clutch input ends of the two one-way clutches, and an input gear coaxially and torsionally connected to the connecting shaft. The clutch input ends and input gears of the two one-way clutches are supported by the connecting shaft and are thus transmission-connected via the connecting shaft.

[0011] According to another preferred embodiment of the present invention, the clutch input ends of the two one-way clutches can respectively abut against the input gears in the axial direction and be fixed together with the input gears, thereby reducing the axial size of the differential device and reducing the installation space.

[0012] According to another preferred embodiment of the present invention, the differential device may further include a housing, wherein the two one-way clutches are encapsulated in the housing. The housing may provide protection for components such as the one-way clutches of the differential device.

[0013] The above technical problem is also solved by a motor vehicle according to the invention. The motor vehicle comprises a differential device having the above characteristics. This motor vehicle thus has all the advantages of the above differential device.

[0014] According to a preferred embodiment of the present invention, the motor vehicle may include at least one main drive axle and at least one auxiliary drive axle, and the differential device is mounted on the at least one auxiliary drive axle. Using such a differential device on the auxiliary drive axle allows the auxiliary drive axle to be disconnected from the drive device when auxiliary wheel drive is not required. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention is further described below with reference to the accompanying drawings. Elements with the same function are represented by the same reference numerals in the drawings.

[0016] FIG1 shows a schematic diagram of a driving system of a motor vehicle to which a differential device according to an exemplary embodiment of the present invention is applied. DETAILED DESCRIPTION

[0017] The following description of the differential device and motor vehicle according to the present invention is provided in conjunction with the accompanying drawings. The following detailed description and accompanying drawings are intended to illustrate the principles of the present invention by way of example only. The present invention is not limited to the preferred embodiments described. The scope of protection of the present invention is defined by the claims.

[0018] According to an embodiment of the present invention, a novel differential device is provided. This differential device can be installed on a vehicle axle to replace a conventional planetary gear differential. The specific structure of this differential device is described below using an exemplary embodiment of the differential device according to the present invention.

[0019] FIG1 is a schematic diagram of a drive system for a motor vehicle employing a differential device according to an exemplary embodiment of the present invention. As shown in FIG1 , the motor vehicle is schematically illustrated as a four-wheeled motor vehicle having two wheel sets and corresponding two axles. However, it should be understood that the differential device of the present invention is also applicable to motor vehicles having more wheel sets and axles.

[0020] In the motor vehicle of Figure 1 , the upper axle is the main drive axle, while the lower axle is the auxiliary drive axle. Each axle extends axially, with the axial direction of the axle extending substantially transversely to the vehicle body. Each axle is mounted with wheels 1 at its axial ends. The two wheels 1 of each axle are coaxially arranged and form a wheelset. Each axle includes two half-shafts 2. The two half-shafts 2 extend axially coaxially with the two wheels 1, respectively. The ends of the two half-shafts 2, facing away from each other, are each connected in a torsionally fixed manner to the corresponding wheel 1. In the main drive axle, the facing ends of the two half-shafts 2 are each connected in a torsionally fixed manner to a conventional planetary gear differential D. The differential D, in turn, is transmission-connected to drive devices such as an internal combustion engine (ICE), a drive motor (TM), and an integrated starter generator (ISG). This transmission connection can be achieved, for example, via a transmission mechanism such as gears, thereby forming the main axle drive system M. In the auxiliary drive axle, the facing ends of the two half-shafts 2 are each connected in a torque-proof manner to a differential device according to the present invention. The differential device, in turn, is drivingly connected to a drive device, such as a drive motor TM, thereby forming the auxiliary axle drive system A. A conventional differential D or the differential device according to the present invention is thus axially mounted between the two half-shafts 2. The drive torque from the drive device can be transmitted via the differential D or the differential device according to the present invention to the two wheels 1 located at the axial ends of the axle.

[0021] As shown in Figure 1, the differential device according to the present invention includes two one-way clutches 3 and a differential device input for receiving drive torque from a drive device. The two one-way clutches 3 are respectively connected between the corresponding half-shafts 2 and the differential device input, thereby replacing a traditional planetary gear differential. Specifically, each one-way clutch 3 includes a clutch input 31 and a clutch output 32. The clutch inputs 31 of the two one-way clutches 3 are simultaneously torsionally connected to the differential device input, while the clutch outputs 32 of the two one-way clutches 3 are respectively torsionally connected to the corresponding half-shafts 2 and, in turn, to the corresponding wheels 1. The differential device is capable of transmitting torque in one direction to the two wheels 1 via the two one-way clutches 3.

[0022] When the one-way clutch 3 rotates in the forward driving direction of the vehicle, the torque can only be transmitted unidirectionally from the clutch input end 31 to the clutch output end 32, and cannot be transmitted in the opposite direction from the clutch output end 32 to the clutch input end 31. Therefore, when the rotational speed of the clutch output end 32 exceeds the rotational speed of the clutch input end 31 (that is, the rotational speed of the wheel 1 exceeds the input rotational speed of the drive device), the wheel 1 cannot transmit torque to the drive device through the one-way clutch 3. Since this non-torque transmission state of the one-way clutch 3 can be manifested as the output end rotational speed exceeding the input end rotational speed, the one-way clutch can also be called an overrunning clutch. The specific structure and principle of this one-way clutch are well known in the prior art and will not be repeated here. In addition, various types of one-way clutches can be applied to the differential device according to the present invention.

[0023] When a motor vehicle turns or deviates from a straight line, the required rotational speeds of the two wheels 1 on either side of the same axle differ. In this case, the required rotational speed of the wheel 1 on the side with the larger radius of curvature exceeds both the rotational speed and the input rotational speed of the wheel 1 on the other side. This causes the output of the one-way clutch 3 on the side with the larger radius of curvature to "overtake" the input, disengaging the one-way clutch 3. This redistributes the rotational speeds of the wheels on either side of the wheelset.

[0024] In a preferred embodiment, the two one-way clutches 3 are coaxially arranged with each other and with the corresponding two wheels 1. The differential input can be axially located between the two one-way clutches 3 and preferably coaxially arranged with the two one-way clutches 3. The differential input can be connected to the corresponding drive device via various transmission methods. For example, the differential input can be implemented as an input gear 4 coaxially arranged with the two one-way clutches 3 and connected to the drive motor TM as the drive device via a gear set.

[0025] The input gear 4 can be connected to the two one-way clutches 3 in an axial manner. Specifically, the differential device can also include a connecting shaft 5 that is coaxially arranged with the two one-way clutches 3. The axial ends of the connecting shaft 5 are coaxially connected to the clutch input ends 31 of the two one-way clutches 3 respectively. The input gear 4 is coaxially mounted on the radial outside of the connecting shaft 5. The clutch input ends 31 of the two one-way clutches 3 and the input gear 4 are respectively torsionally connected to the connecting shaft 5. The connecting shaft 5 thus provides torque transmission and rotation support functions for the clutch input ends 31 and the input gear 4 at the same time. The input gear 4 is axially located between the two clutch input ends 31 and can be spaced apart along the axial direction. The spacing distance between the input gear 4 and the two clutch input ends 31 can be designed according to the needs of the layout space.

[0026] Alternatively, the input gear 4 and the two one-way clutches 3 may be connected directly. Specifically, the clutch input ends 31 of the two one-way clutches 3 may respectively abut the input gear 4 in the axial direction and be fixed to the input gear 4 (e.g., welded or integrally formed), thereby integrating the two clutch input ends 31 and the input gear 4 together, thereby omitting the connecting shaft 5 and saving axial space.

[0027] Preferably, the differential device may further include a housing (not shown). The two one-way clutches 3 (and possibly the input gear 4 and the connecting shaft 5) may be enclosed in the housing. The housing may provide protection for the one-way clutches 3 and may integrate the various components into a relatively independent product.

[0028] The novel differential device according to the present invention uses two one-way clutches to replace the traditional planetary gear differential, effectively achieving wheel differential function. Furthermore, this differential device has a simple structure, low cost, and is compact, occupying little space, and therefore has excellent application prospects.

[0029] According to an embodiment of the present invention, a motor vehicle is also provided, comprising a differential device according to the above-described embodiment. As shown in FIG1 , the motor vehicle according to the present invention comprises at least one main drive axle and at least one auxiliary drive axle. The differential device is mounted only on the auxiliary drive axle, while all main drive axles utilize conventional planetary gear differentials D.

[0030] In addition to the aforementioned advantages of this differential device, a motor vehicle with this layout can also utilize the differential device to disconnect the drive torque of the auxiliary drive axle in a non-all-wheel drive state (e.g., a two-wheel drive state). Specifically, when the output speed of the drive motor TM of the auxiliary drive axle to be disconnected is lower than the output speed of the engine ICE in the drive device of the main drive axle, the wheels 1 of the auxiliary drive axle "overtake" the differential device input because their rotational speed is the same as that of the main drive axle and higher than the output speed of the drive motor TM of the auxiliary drive axle. This causes the wheels 1 of the auxiliary drive axle to "overtake" the differential device input, causing the differential device to enter a disconnected state, thereby achieving the disconnection function of the auxiliary drive axle. This enables the differential device to simultaneously achieve both differential and disconnection functions, thereby eliminating the independent disconnection mechanism used in the prior art and further saving cost and layout space.

[0031] While the foregoing descriptions illustrate possible embodiments, it should be understood that numerous variations exist through combinations of all known and other technical features and implementations readily conceivable to a skilled artisan. Furthermore, it should be understood that the exemplary embodiments serve merely as examples and in no way limit the scope, application, or configuration of the present invention. The foregoing descriptions are intended primarily to provide a skilled artisan with technical guidance for implementing at least one exemplary embodiment. Various modifications, particularly regarding the functionality and structure of the components described, may be made without departing from the scope of the claims.

[0032] Reference Signs 1 Wheel 2 Axle shaft 3 One-way clutch 31 Clutch input 32 Clutch output 4 Input gear 5 Connecting shaft D Differential M Main axle drive system A Auxiliary axle drive system ICE Engine (Internal Combustion Engine) TM Drive motor ISG Generator

Claims

1. A differential device for transmitting the driving torque from a driving device to two wheels (1) located at the axial ends of an axle, It is characterized in that The differential device comprises two one-way clutches (3) and a differential device input end for receiving a driving torque from the driving device. The two one-way clutches (3) each comprise a clutch input end (31) and a clutch output end (32). The clutch input ends (31) of the two one-way clutches (3) are simultaneously torsionally connected to the differential device input end, and the clutch output end (32) of each one-way clutch (3) is respectively torsionally connected to a corresponding one of the two wheels (1), so that the differential device can transmit torque to the two wheels (1) in one direction respectively.

2. The differential device according to claim 1, It is characterized in that The two one-way clutches (3) are coaxially arranged.

3. The differential device according to claim 2, It is characterized in that The input end of the differential device is located between the two one-way clutches (3) in the axial direction.

4. The differential device according to claim 3, It is characterized in that The differential device further comprises an input gear (4) serving as an input end of the differential, wherein the input gear (4) is coaxially arranged with the two one-way clutches (3).

5. The differential device according to claim 4, It is characterized in that The differential device also includes a connecting shaft (5) arranged coaxially with the two one-way clutches (3), the axial ends of the connecting shaft (5) are respectively coaxially and torsionally connected to the clutch input ends (31) of the two one-way clutches (3), and the input gear (4) is coaxially and torsionally connected to the connecting shaft (5).

6. The differential device according to claim 4, It is characterized in that The clutch input ends (31) of the two one-way clutches (3) respectively abut against the input gear (4) along the axial direction and are fixed together with the input gear (4).

7. The differential device according to any one of claims 1 to 6, It is characterized in that The differential device further comprises a housing, in which the two one-way clutches (3) are encapsulated.

8. A motor vehicle, It is characterized in that The motor vehicle comprises a differential arrangement according to any one of claims 1 to 7.

9. A motor vehicle according to claim 8, It is characterized in that The motor vehicle comprises at least one main drive axle and at least one auxiliary drive axle, and the differential device is mounted on the at least one auxiliary drive axle.

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