Axle drive for vehicle

Abstract

The invention relates to an axle drive for a vehicle, having at least one electric machine (1) as a drive and having a transmission (2) which is coupled to an output shaft (4, 5) via an output differential (3) for driving wheels, an overload decoupling device (6) being provided, the torque flow of which in the torque flow direction is greater than the torque flow direction of the output shaft (4, 5), and the torque flow of which in the torque flow direction is greater than the torque flow direction of the output shaft (4, 5) is greater than the torque flow direction of the output shaft (4, 5). The overload decoupling device (6) is arranged between the driven differential (3) and the driven shaft (4, 5).

Description

Field of the Invention

[0001] The present invention relates to an axle drive for a vehicle, wherein the axle drive has at least one electric motor as a drive and a transmission which is coupled to a driven axle via a driven differential for driving wheels, and wherein an overload decoupling device is provided. Background Art

[0002] For example, a vehicle drive with an electric motor is known from the published document JP 2020 106 048A. The electric motor is coupled to a differential transmission via an overload decoupling device via a planetary gear transmission as a reduction transmission, wherein the differential transmission is connected to a driven axle for driving wheels. Therefore, by arranging the overload decoupling device on the drive side, more precisely upstream of the driven differential, in the torque path, only an overload occurring due to the electric motor acting on the differential transmission can be prevented. However, it has been shown that the load on the driven side is particularly disadvantageous because the load occurs, for example, at the wheels and is transmitted to the driven axle, so that components on the driven side can be damaged during load transmission. Summary of the Invention

[0003] The object of the present invention is to provide the axle drive described at the beginning, which advantageously prevents damage caused by loads occurring on the drive side and the driven side.

[0004] According to the present invention, this object is achieved by the features of claim 1. Advantageous and claimed improvements result from the dependent claims, the description and the drawings.

[0005] Therefore, an axle drive for a vehicle is proposed, which has at least one electric motor as a drive and a transmission, wherein the transmission is coupled to a driven axle via a driven differential for driving wheels, and wherein an overload decoupling device is provided. In order to advantageously avoid damage caused by occurring overloads, more precisely torque peaks, it is provided that the overload decoupling device is arranged between the driven differential and the driven axle with respect to the torque flow or torque path.

[0006] In this way, in the proposed axle drive, when an overload occurs on the drive side and / or on the driven side between the driven differential and the driven axle, the torque transmission is interrupted by the provided overload decoupling device, thereby preventing damage, especially damage at the driven axle.

[0007] For the proposed axle drive, it is particularly preferred that the electric motor and / or the transmission is arranged coaxially with the driven shaft. In a particularly space-saving and cost-effective coaxial arrangement, the electric motor and a transmission, such as a planetary gear transmission, are arranged axially side by side, such that at least one of the driven shafts in the driven shafts is axially guided through the electric motor and the transmission. For the proposed axle drive, by means of an overload decoupling device arranged between the differential transmission and the driven shaft, it is possible to use driven shafts that are more cost-effective and dimensionally designed to be very small without problems, because for the proposed axle drive, the load that may act on the driven shaft is advantageously prevented by the provided overload decoupling device.

[0008] For the proposed axle drive, it is particularly advantageous that the overload decoupling device includes a first coupling element and a second coupling element, between which a form-fitting or frictionally connected torque transmission part that can be decoupled according to the load is provided. Thereby, when a torque peak occurs, the torque transmission can be interrupted by simply separating the form-fitting connection or the friction connection between the coupling elements.

[0009] For example, the coupling elements can be form-fittingly connected to each other by teeth designed with a repulsive tooth geometry and preloaded against each other. For this purpose, the teeth of the tooth part, more precisely the tooth flanks, can have different tooth angles on both sides, for example, such that when the vehicle is moving forward or backward, an axial force acts on the coupling elements, which causes an axial decoupling movement at the two coupling elements starting from a predetermined torque, such that the coupling elements move and disengage the tooth part.

[0010] It is also conceivable that for the proposed axle drive, the coupling elements are frictionally connected to each other via friction surfaces preloaded against each other. For example, it is conceivable that the friction surfaces are designed such that starting from a predetermined torque, the frictional connection between the friction surfaces of the two coupling elements is interrupted, so that torque cannot be transmitted, for example, when a torque peak occurs.

[0011] In order to prevent a load from occurring at the driven shaft during overload, it is stipulated that the first coupling element is connected to a component of the driven differential, for example, and the second coupling element is connected to one of the driven shafts.

[0012] In principle, it is conceivable that for the proposed electric axle drive, a planetary gear transmission (i.e., Planetengetriebe), a bevel gear differential transmission, a spur gear differential transmission, or a helical gear differential transmission is used as the driven differential, for example. However, it is particularly advantageous to use a bevel gear differential transmission, which is particularly cost-effective, as the driven differential. Description of the Drawings

[0013] The present invention will be further explained below with reference to the drawings. Among them:

[0014] Figure 1 Shows a cross-sectional schematic diagram of a feasible embodiment of an electric axle drive according to the present invention, in which the arrangement position of an overload decoupling device between a driven differential and one of the driven shafts is shown;

[0015] Figure 2 Shows a detailed cross-sectional view of the overload decoupling device of the axle drive;

[0016] Figure 3 Shows a part view of the first coupling element of the overload decoupling device;

[0017] Figure 4 Shows a part view of the second coupling element of the overload decoupling device; and

[0018] Figure 5 Shows a detailed cross-sectional view of the overload decoupling device when the coupling element is in the decoupled state. Detailed implementation

[0019] Figures 1 to 5 Shows different views of an electric axle drive according to the present invention for a vehicle, in particular a commercial vehicle.

[0020] The proposed axle drive has an electric motor 1 as the drive and a transmission 2, which is located in a housing. Here, the transmission 2 is coupled to the driven shafts 4, 5 via a driven differential 3 for driving wheels not shown in detail. In addition, an overload decoupling device, more precisely an overload clutch 6, is provided, which is arranged between the driven differential 3 and the driven shafts 4, 5 in terms of the torque flow or torque path.

[0021] As can be seen in particular from Figure 1 it can be seen that the electric motor 1 and the transmission 2 are arranged coaxially with the driven shafts 4, 5. Here, the electric motor 1 and the transmission 2 are arranged side by side axially and axially next to the driven differential 3, such that the driven shaft 4 is axially guided through the electric motor 1 and through the transmission 2.

[0022] Especially in the field of commercial vehicles, different vehicle applications bring a wide range of requirements, so that the axle drive must be designed more strongly for specific applications. These applications can generate very high and destructive load peaks during the alternation of traction and pushing. Another application is the use of a differential lock when forgetting to deactivate it. This generates high static friction at the wheels during cornering, so that high torque acts on the driven shafts.

[0023] In Figure 1In the figure, two possible arrangement positions of the overload decoupling device 6 between the driven differential 3 and the driven shafts 4, 5 are shown by way of example by dashed lines in order to prevent the loads described above on the axle drive and in this way to enable the use of correspondingly smaller components, thereby reducing the costs of the proposed axle drive as a whole.

[0024] Figure 2 A detailed view of the axle drive in the region of the output differential 3 designed as a bevel gear differential and the overload decoupling device 6 and the associated output shaft 5 is shown, which corresponds to the overload decoupling device 6 in the Figure 1 The arrangement position on the right side of the drawing plane of FIG. 6 , wherein the overload decoupling device 6 is Figure 1 The layout position on the left side of the drawing plane and the structure are the same.

[0025] The overload decoupling device 6 comprises a first coupling element 7 and a second coupling element 8, between which a torque transmission part which is connected in a form-fitting manner and can be decoupled according to the load is provided. The first coupling element 7 is connected to the axle bevel gear as the driven gear of the driven differential 3 in a non-rotatable manner. The second coupling element 8 is connected to the driven shaft 5 in a non-rotatable manner and axially movable manner.

[0026] In particular, from Figure 3 It can be clearly seen that the first coupling element 7 has a cylindrical shape with an external toothing 10, wherein the external toothing 10 meshes with the internal toothing of the axle bevel gear 9 of the bevel gear output differential 3, wherein an end-side claw profile toothing 11 is formed on the cylindrical shape of the first coupling element 7 on the axial side, which end-side claw profile toothing has a push-off tooth geometry.

[0027] In particular, from Figure 4 It can be clearly seen that the second coupling element 8 has a sleeve-shaped base body with an internal toothing 12 for non-rotatably connecting to the external toothing of the driven shaft 5 designed as a plug-in shaft, wherein a front-side claw profile toothing 13 is formed on the base body on the axial side, which also has a push-off tooth geometry. In the event of an overload, more precisely a torque peak, the second coupling element 8 can be axially moved along the internal toothing 12 against the spring element 14 to decouple the corresponding front-side claw profile toothing 11, 13 of the coupling elements 7, 8.

[0028] In the overload decoupling device 6 shown, the two coupling elements 7, 8 can be axially moved relative to each other by the axial movement of the second coupling element 8 configured as a sliding sleeve. The sleeve 15, together with the spring element 14 and the retaining ring 16, preloads the two coupling elements 7, 8 to a degree that can just transmit a predetermined nominal torque.

[0029] Thus, the two coupling elements 7, 8 of the overload decoupling device 6 can transmit torque due to the preloading applied up to a defined limit. If this limit is exceeded, for example due to load peaks occurring on the drive or the driven side, the two coupling elements 7, 8 are decoupled from each other by an axial movement of the second coupling element 8, in such a way that the two end-side claw-shaped profile teeth 11, 13 no longer engage, as shown, for example, in Figure 5 Thus, the axle drive can continue to operate normally without any component being unnecessarily damaged by overload.

[0030] List of reference numerals

[0031] 1 Electric motor

[0032] 2 Transmission

[0033] 3 Driven differential, more precisely bevel gear driven differential

[0034] 4 Driven shaft

[0035] 5 Driven shaft

[0036] 6 Overload decoupling device, more precisely overload clutch

[0037] 7 First coupling element

[0038] 8 Second coupling element

[0039] 9 Axle bevel gear, more precisely driven gear

[0040] 10 External teeth of the first coupling element

[0041] 11 End-side claw-shaped profile teeth of the first coupling element

[0042] 12 Internal teeth of the second coupling element

[0043] 13 End-side claw-shaped profile teeth of the second coupling element

[0044] 14 Spring element or spring group

[0045] 15 Sleeve

[0046] 16 Snap ring.

Claims

1. An axle drive for a vehicle, the axle drive comprising: at least one electric motor (1) serving as a drive; and A transmission (2) coupled to a driven shaft (4, 5) via a driven differential (3) for driving wheels, in, An overload decoupling device (6) is provided. The invention is characterized in that, in terms of torque flow, the overload decoupling device (6) is arranged between the output differential (3) and the output shaft (4, 5).

2. The axle drive according to claim 1, characterized in that The overload decoupling device (6) comprises a first coupling element (7) and a second coupling element (8), between which a positively locking or frictionally locking torque transmission portion which can be decoupled depending on the load is provided.

3. The axle drive according to claim 2, characterized in that: The coupling elements (7, 8) are connected to one another in a form-fitting manner via toothings which are designed with a push-off tooth geometry and which are preloaded against one another.

4. The axle drive according to claim 2, characterized in that: The coupling elements (7, 8) are frictionally connected to one another via friction surfaces which are preloaded against one another.

5. The axle drive according to any one of claims 2 to 4, characterized in that The first coupling element (7) is connected to the output differential (3), and the second coupling element (8) is connected to one of the output shafts (4, 5).

6. The axle drive according to claim 5, characterized in that The first coupling element (7) is connected to the driven gear (9) of the driven differential (3) in a rotationally fixed manner, and the second coupling element (8) is connected to one of the driven shafts (4, 5) in a rotationally fixed manner and axially displaceable manner.

7. The axle drive according to claim 6, characterized in that The first coupling element (7) has a cylindrical shape with an external toothing (10) which meshes with an internal toothing of a driven gear (9) of the driven differential (3), wherein an end-side claw profile toothing (11) is formed on the cylindrical shape on the axial side and has a push-off toothing geometry.

8. The axle drive according to any one of claims 5 to 7, characterized in that The second coupling element (8) has a sleeve-shaped base body with an internal toothing (12) for being connected to the external toothing of one of the driven shafts (4, 5) in a rotationally fixed manner, wherein an end-side claw profile toothing (13) is formed on the base body on the axial side and has a push-off toothing geometry.

9. The axle drive according to claim 8, characterized in that In the event of an overload, the second coupling element (8) can be axially displaced along the internal toothing (12) against a spring element (14) in order to decouple the corresponding end-side claw profile toothings (11, 13) of the coupling elements (7, 8).

10. Axle drive according to any one of the preceding claims, characterized in that The driven differential (3) is designed as a bevel gear differential transmission device.

11. Axle drive according to any one of the preceding claims, characterized in that The motor (1) and / or the transmission device (2) are arranged coaxially with the driven shaft (4, 5).

12. The axle drive according to claim 11, characterized in that The electric motor (1) and the transmission (2) are arranged axially side by side, so that at least one of the driven shafts (4, 5) is axially guided through the electric motor (1) and the transmission (2).

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