Drive device for axle of a vehicle

Abstract

The invention relates to a drive device for an axle (VA) of a vehicle with two wheels, the drive device comprising a drive unit, in particular an electric motor (EM), which acts on at least one drive shaft (9) leading to a wheel (5) on the output side, the drive shaft (9) being divided into a wheel-side shaft section (17) and an axle-side shaft section (19), the two shaft sections being driveably coupled to one another or decoupled from one another by means of a positive clutch (21) in order to avoid drag losses in the deactivated drive unit (EM) when the drive unit (EM) is deactivated during driving operation.

Description

Technical Field

[0001] The invention relates to a drive device for an axle of a double-track vehicle. Background Art

[0002] In this type of all-wheel drive vehicle with electric drive, the front axle and the rear axle can have at least one electric motor independently of each other. For example, depending on the driving operation, the electric motor of the front axle is not powered and only the electric motor of the rear axle is powered, so that the vehicle is driven only by the rear axle. This improves the overall efficiency and increases the effective range. However, in this pure rear-axle operation, friction losses (air and bearing friction, meshing friction in the transmission, oil churning losses, etc.) occur due to the towed, deactivated front axle drive.

[0003] A drivetrain for a vehicle with a clutch-controlled all-wheel drive is known from DE 10 2015 210 227 A1. An actuating device for a claw clutch is known from DE 20 2015 000 397 U1. An electromagnetic clutch is known from DE 1 575 783 A. Summary of the invention

[0004] The object of the present invention is to provide a drive device for an axle of a vehicle, in particular for electrically operated vehicles, in which the drag losses in a deactivated drive unit can be reduced during driving operation.

[0005] According to the invention, the drive unit acts on the output side on at least one drive shaft leading to the vehicle wheels. The drive shaft is divided into a wheel-side shaft section and an axle-side shaft section, which can be coupled to one another or decoupled from one another by means of a positive clutch. In the decoupled state, no torque is transmitted between the wheel-side shaft section and the axle-side shaft section, so that drag losses in the deactivated drive unit are avoided during driving operation and when the drive unit is deactivated. In this way, for example, the axle, in particular the front axle, can be disconnected or coupled as required, preferably independently of the driving state.

[0006] In one technical embodiment, the positive-locking clutch has a sleeve which is arranged on the spline toothing of the first shaft section in a rotationally fixed manner but axially displaceable. The sleeve can be moved by means of an axial adjustment force generated by an actuator between a clutch disengaged state in which the sleeve is released from the positive-locking connection with the second shaft section and a clutch engaged state in which the sleeve is positively connected with the second shaft section.

[0007] In the area of ​​the axle, a compact design of the interlocking clutch with the actuator that reduces the installation space is very important. In this context, the actuator is assigned an actuator sleeve, which is arranged on the outer circumference of a cylindrical sleeve. In order to decouple the rotation of the sleeve that rotates during operation, the actuator sleeve can be supported on the outer circumference of the sleeve by at least one rolling bearing, specifically so that the axial adjustment force generated by the actuator is transmitted to the sleeve via the rotationally decoupled actuator sleeve and the rolling bearing.

[0008] In a first embodiment variant, for transmitting the adjusting force, both the outer bearing ring of the rolling bearing and the inner bearing ring of the rolling bearing are connected to the actuator sleeve in an adjusting force-transmitting manner.

[0009] The actuator sleeve can be adjusted by means of an actuator between an open position, in which the positive clutch is open, and a closed position. For this purpose, the actuator can cooperate with the actuator sleeve via a transmission stage. In a space-saving embodiment, the transmission stage can have an external toothing on the outer circumference of a cylindrical sliding sleeve. In the external toothing, the teeth are spaced apart from each other in the axial direction and mesh with a gear wheel of an actuator shaft of an electric motor forming the actuator.

[0010] Preferably, the positive clutch is designed as a claw clutch, wherein the sleeve and the second shaft section have axially facing shifting claws on the wheel side and on the axle side. The cylindrical outer circumference of the sleeve can transition into a shifting claw with a larger diameter by forming an inner angle region. In the inner angle region thus formed, the actuator sleeve can be arranged in a space-saving manner.

[0011] During the closing process of the above-described claw clutch, the shifting claws on the wheel side and on the axle side are axially opposite to each other in the manner of tooth-to-gap, so that a smooth positive-locking clutch can be achieved. In the more likely case, on the other hand, during the closing process, the shifting claws first come into contact tooth-to-tooth contact. Starting from the achievement of tooth-to-tooth contact, according to the invention, the actuator sleeve is further adjusted until it enters its closed position, and the shifting claws on the wheel side and on the axle side are tensioned against each other by means of the overload spring while the spring force of the overload spring axially acting on the shifting claw is generated. As soon as the shifting claw is brought into the relative position of the tooth-to-gap by a small relative angular rotation of the two clutch halves, the shifting claws on the wheel side and on the axle side can be connected in a positive-locking manner when the spring force is reduced.

[0012] In one technical embodiment, the wheel-side shifting claw can be constructed on a support ring, which is arranged on the wheel-side shaft section in a rotationally fixed manner and axially displaceable manner by means of a splice toothing. The support ring can be pressed against an axial stop of the wheel-side shaft section on its side axially opposite to the axle-side shaft section by means of the above-mentioned overload spring. Therefore, when the wheel-side and axle-side shifting claws are tooth-to-tooth in the closing process of the claw clutch, the actuator sleeve together with the sliding sleeve is adjusted into the closed position, so that the sliding sleeve adjusts the compensation travel on the wheel-side shaft section while generating a spring force. As soon as the tooth-to-gap is achieved by a small relative angular rotation of the two clutch halves, a positive connection is achieved, in which the wheel-side support ring is positively connected to the axle-side shifting claw while consuming the above-mentioned compensation travel and when the spring force is reduced.

[0013] Next, a second embodiment variant is described, in which the actuator sleeve is no longer mounted on the bearing outer ring of the rolling bearing in a manner that transmits the adjustment force, but is instead mounted on the bearing outer ring of the rolling bearing in an axially movable manner. The bearing inner ring of the rolling bearing is held in a fixed axial position as before and is arranged on the sleeve in a manner that cannot rotate relative to each other, that is, in a manner that transmits the adjustment force. An annular gap can be provided between the actuator sleeve and the cylindrical sleeve outer circumference, in which the overload spring is arranged. The overload spring is supported axially between the actuator sleeve axial stop and the rolling bearing outer ring. Thus, during the closing process, the actuator sleeve and the sleeve are adjusted in a motion-coupled manner until tooth-to-tooth contact is achieved. Starting from the tooth-to-tooth contact, the actuator sleeve is further adjusted in a manner that is decoupled from the sleeve motion until it enters its closed position, specifically under the condition that the elastic force of the overload spring is formed. By a small relative angular rotation of the two clutch halves, the shifting claw is brought into a relative position of the tooth to the intermediate space, so that when the spring force of the overload spring is reduced, the sliding sleeve together with the axle-side shifting claw formed thereon is connected in a positively locking manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Two embodiments of the present invention are described below with reference to the drawings.

[0015] In the attached picture:

[0016] Figure 1 An electric vehicle is shown from above in a simplified schematic diagram, wherein the axles are highlighted and schematically illustrated;

[0017] Figure 2 A drive arrangement for the front axle of a vehicle is shown;

[0018] Figure 3 A first embodiment of a dog clutch is shown in a partial view, which shows the dog clutch in a clutch-disengaged state;

[0019] Figure 4 Shows the corresponding Figure 3 A view showing the closing process of the claw clutch;

[0020] Figure 5 and Figure 6 The corresponding Figure 3 and Figure 4 , which shows the working principle of the overload spring. DETAILED DESCRIPTION

[0021] exist Figure 1 , an electric vehicle is shown, which has an electrically drivable front axle VA and an electrically drivable rear axle HA. The front axle VA is equipped with exactly one electric motor EM, which acts on the left and right drive shafts 7, 9 leading to the right and left front wheels 5 via a front axle differential 3. The rear axle HA has a drive device, in which, unlike the front axle VA, each of the rear wheels 15 is assigned an electric motor EM1, EM2, which is connected to the drive shaft 11 of the rear axle HA via transmission stages U1, U2. As can also be seen from Figure 1 As can be seen in FIG. 1 , the front right drive shaft 9 is divided into a wheel-side shaft section 17 and an axle-side shaft section 19 , which can be coupled or decoupled from one another by means of a claw clutch 21 .

[0022] Therefore, during driving operation, when the claw clutch 21 is open, only the load-free differential movement of the differential bevel gear 29 remains in the front axle differential 3. On the contrary, the rest of the drive unit (ie the transmission and the electric machine) is stationary, so that friction losses are significantly reduced.

[0023] For coupling (ie, when the dog clutch 21 is closed), the electric motor EM is first supplied with power and thereby synchronizes the movable part of the dog clutch 21 with the current wheel speed. If approximate synchronization is achieved, the actuator 49 is activated. As described later, the actuator 49 acts via a toothing on a non-rotating actuator sleeve 53. The actuator sleeve is pressed onto the movable part of the dog clutch 21 via a spring-ball bearing combination.

[0024] according to Figure 2 The electric motor EM of the front axle VA is drivingly connected to the external gear 25 on the input side of the front axle differential 3 via the intermediate shaft 23. On the output side of the front axle differential 3, the axle bevel gear 27 is connected to the two drive shafts 7 and 9. The axle bevel gear 27 and the differential bevel gear 29 meshing therewith are positioned within the differential housing 31 of the axle differential 3.

[0025] Next, according to Figure 3 and Figure 4The structure and operation principle of the claw clutch 21 according to the first embodiment will be described. Figure 3 In the embodiment, the axle bevel gear 27 is extended by a hollow axle shaft, which forms the axle-side shaft section 19. Radially inside the hollow axle shaft 19, an insert shaft leading to the front wheel 5 is rotatably supported, which forms the wheel-side shaft section 17. Figure 3 In FIG. 2 , the dog clutch 21 has an axle-side shift claw 33 and a wheel-side shift claw 35 , which are connected to each other in a form-locking manner when the dog clutch 21 is closed. Figure 3 In the embodiment, the axle-side shifting claw 33 is a component of a sliding sleeve 37, which is arranged in a rotationally fixed manner but axially displaceable on a spline toothing 39 of the hollow axle shaft 19. The wheel-side shifting claw 35 is formed on a support ring 41, which is supported in a rotationally fixed manner but axially displaceable on the plug-in shaft 17 via a spline toothing 43. The support ring 41 is placed on its side axially opposite to the hollow axle shaft 19 against an axial stop 47 of the plug-in shaft 17 by means of an overload spring 45.

[0026] exist Figure 3 In the embodiment, the sleeve 37 arranged axially displaceably on the hollow axle shaft 19 can be actuated by an actuator 49, which is realized as an electric motor. The actuator 49 is drivingly connected to an actuator sleeve 53 via a transmission stage 51. The actuator sleeve is arranged on a cylindrical sleeve outer circumference 55. In order to decouple the rotation from the sleeve 37 rotating during operation, the actuator sleeve 53 is supported on the cylindrical sleeve outer circumference 55 by two rolling bearings (optionally also by sliding bearings) 57, 59. Figure 3 In the embodiment, the bearing outer ring 61 of the rolling bearing 57, 59 is pressed into the inner circumference of the actuator sleeve 53, that is, connected to the actuator sleeve 53 in a manner that transmits the adjusting force. In addition, the bearing inner ring 63 of the rolling bearing 57, 59 is pressed onto the outer circumference 55 of the sliding sleeve, that is, connected to the sliding sleeve 37 in a manner that transmits the adjusting force. In this way, the axial adjusting force Fs generated by the actuator 49 is transmitted to the sliding sleeve 37 through the rotationally decoupled actuator sleeve 53 and further through the two rolling bearings 57, 59.

[0027] exist Figure 3 In the embodiment, the transmission stage 51 connected between the actuator 49 and the actuator sleeve 53 is formed by a drive gear 67 formed on the actuator shaft, which meshes with an external toothing 69 on the outer circumference of the sliding sleeve 37. The external toothing 69 has teeth spaced apart from each other in the axial direction.

[0028] Next, according to Figure 3The closing process of the dog clutch 21 is described, in which the wheel-side and axle-side shifting claws 33, 35 are axially opposite each other in the form of teeth 58 and gaps 60. In this case, the actuator 49 is activated in order to move the actuator sleeve 53 together with the sliding sleeve 37 coupled thereto from the illustrated open position I into the closed position S, in which the wheel-side and axle-side shifting claws 33, 35 are smoothly engaged.

[0029] according to Figure 4 The closing process is described in which the wheel-side and axle-side shifting claws 33, 35 are not axially opposite each other in the manner of tooth 58 to gap 60, but rather in the manner of tooth 58 to tooth 58. In this case, during the closing process, the wheel-side and axle-side shifting claws 33, 35 first abut against each other in the manner of tooth 58 to tooth 58. Starting from the realization of tooth 58 to tooth 58 abutment ( Figure 4 ), continue to adjust the actuator sleeve 53 together with the sliding sleeve 37 to adjust the overload stroke Δh (at Figure 4 The support ring 41 is moved by the overload path Δh on the insertion shaft 17 under the spring force of the overload spring 45. As soon as the tooth 58 faces the gap 60 due to a small relative angle rotation, the support ring 41 is suddenly connected to the axle-side shifting claw 33 of the sliding sleeve 37 in a form-fitting manner when the overload path Δh is consumed and the spring force of the overload spring 45 is reduced.

[0030] exist Figure 5 and Figure 6 A second embodiment is shown in FIG. 4 , in which the support ring 41 is no longer axially displaceable, but is instead pressed axially fixed and rotationally fixed on the plug-in shaft 17 . Figure 5 In the embodiment shown, the overload spring 45 is arranged in an annular gap 71 between the actuator sleeve 53 and the cylindrical sliding sleeve outer circumference 55 .

[0031] exist Figure 5 In the embodiment, unlike the first embodiment, the actuator sleeve 53 is no longer arranged in an axially movable manner on the bearing outer ring 61 of the corresponding rolling bearing 57, 59 in a manner that transmits adjustment forces. The bearing inner ring 63 of the rolling bearing 57, 59 is positioned on the sliding sleeve 37 in an axially fixed manner and in a manner that cannot rotate relative to each other, that is, in a manner that transmits adjustment forces. Figure 5 In the embodiment of the present invention, the overload spring 45 is supported in the axial direction between the axial stop 73 of the actuator sleeve 53 and the intermediate disk 75. The intermediate disk is movably positioned within the annular gap 71 and presses against the bearing outer ring 61 of the rolling bearing 57.

[0032] Next, describe Figure 5The closing process of the claw clutch 21 is shown in FIG. Figure 5 In the embodiment, the shift claws 33, 35 on the wheel side and on the axle side are relative to each other in the form of teeth 58 to gaps 60, so that the actuator sleeve 53 together with the sliding sleeve 37 can be smoothly adjusted into the closed position II in a motion-coupled manner to establish a positive connection between the shift claws 33, 35 on the wheel side and on the axle side.

[0033] according to Figure 6 The closing process is described in which the shifting claws 33, 35 are positioned relative to one another in the manner of tooth 58 against tooth 58. In this case, during the closing process, the actuator sleeve 53 together with the sliding sleeve 37 is first adjusted in a motion-coupled manner, to be precise until abutment of tooth 58 against tooth 58 is achieved ( Figure 6 ). From achieving the abutment of teeth 58 against teeth 58 ( Figure 6 ), the actuator sleeve 53 is further adjusted by the overload travel Δh (decoupled from the movement of the sliding sleeve 37) until it reaches its closed position II, specifically under the formation of the spring force of the overload spring 45. By a small relative angular rotation, the shifting claws 33, 35 are brought into the relative position of the teeth 58 to the recesses 60, so that when the spring force disappears, the shifting claws 33, 35 can be suddenly connected in a positively locking manner.

[0034] For coupling (closing process), the electric motor EM is first supplied with power and the movable part of the clutch is thereby synchronized with the wheel speed. If approximate synchronization is achieved, the actuator 49 is activated, which acts via the toothing on the non-rotating actuator sleeve 53. The actuator sleeve is pressed onto the movable part of the claw clutch via the spring ball bearing combination.

[0035] Reference numerals list

[0036] 3Front axle differential

[0037] 5Front wheel

[0038] 7.9 Drive shaft of the front axle

[0039] 11 Rear axle drive shaft

[0040] 15 Rear wheel

[0041] 17 Axle section on the wheel side

[0042] 19 Axle section on the axle side

[0043] 21-claw clutch

[0044] 23Intermediate shaft

[0045] 25 External gear

[0046] 27 Axle bevel gear

[0047] 29 Differential bevel gear

[0048] 31 Differential housing

[0049] 33 Shift claw on axle side

[0050] 35 Shift claw on wheel side

[0051] 37 Slide

[0052] 39 splice teeth

[0053] 41 Loading ring

[0054] 43 splice teeth

[0055] 45 Overload Spring

[0056] 47 axial stop

[0057] 49 actuator

[0058] 51 transmission level

[0059] 53 actuator sleeve

[0060] 54 inner corner area

[0061] 55 cylindrical sleeve outer circumference

[0062] 57, 59 rolling bearings

[0063] 61 bearing outer ring

[0064] 63 bearing inner ring

[0065] 67 driving gear

[0066] 69 external teeth

[0067] 71 Annular gap

[0068] 73 axial stop

[0069] 75 middle plate

[0070] EM, EM1, EM2 motors

[0071] U1, U2 transmission stage

[0072] Δh overload travel

[0073] I Disconnect position

[0074] II Closed position

Claims

1. A drive device for an axle (VA) of a double-track vehicle, the drive device comprising a drive unit which acts on at least one drive shaft (9) leading to a wheel (5) on the output side, wherein: The drive shaft (9) is divided into a first shaft section (17) on the wheel side and a second shaft section (19) on the axle side, the two shaft sections being driveably coupled to or decoupled from each other by means of a positive clutch (21) in order to avoid drag losses in the deactivated drive unit (EM) when the drive unit (EM) is deactivated during driving operation, wherein the positive clutch (21) has a sleeve (37) which is arranged on a spline toothing (39) of the first shaft section (17) in a rotationally fixed manner but axially displaceable, an actuator sleeve (53) is assigned to the actuator (49) and is arranged on the cylindrical outer circumference (55) of the sleeve, and is characterized in that in order to be coupled to the actuator during driving operation The sliding sleeve (37) rotating in the clutch is rotationally decoupled, and the actuator sleeve (53) is supported on the outer periphery (55) of the sliding sleeve by at least one rotary bearing (57, 59), so that the axial adjustment force (Fs) generated by the actuator (49) is transmitted to the sliding sleeve (37) through the rotationally decoupled actuator sleeve (53) and the rotary bearing (57, 59), wherein the sliding sleeve (37) can be moved between a clutch disengaged state and a clutch engaged state by means of the axial adjustment force (Fs) generated by the actuator (49), in which the sliding sleeve (37) is released from a positively locked connection with the second shaft section (19) in the clutch disengaged state, and in which the sliding sleeve (37) is positively locked with the second shaft section (19) in the clutch engaged state.

2. The driving device according to claim 1, characterized in that: In order to transmit the adjusting force, not only the outer ring (61) of the rotating bearing (57, 59) is connected to the actuator sleeve (53) in a manner that transmits the adjusting force, but also the inner ring (63) of the rotating bearing (57, 59) is connected to the sliding sleeve (37) in a manner that transmits the adjusting force.

3. The driving device according to claim 1 or 2, characterized in that: The actuator sleeve (53) can be adjusted between a disconnected position (I) and a closed position (II) in which the positive clutch (21) is disconnected by means of an actuator (49), and / or the actuator (49) cooperates with the actuator sleeve (53) via a transmission stage (51). In order to realize the transmission stage (51), an external toothing (69) is constructed on the outer circumference of the sliding sleeve (37), the external toothing having teeth spaced apart from each other in the axial direction, which mesh with a gear wheel (67) of an actuator shaft (65) of the actuator (49).

4. The driving device according to claim 1 or 2, characterized in that: The sleeve (37) and the second shaft section (19) have axially facing, wheel-side and axle-side shift claws (33, 35), the cylindrical sleeve outer circumference (55) transitioning into a shift claw with a larger diameter while forming an inner corner region, the actuator sleeve (53) being spatially appropriately arranged in the inner corner region (54).

5. The driving device according to claim 4, characterized in that: During the closing process, either the shift claws (33, 35) on the wheel side and the axle side are opposite to each other in the form of teeth (58) against gaps (60), thereby smoothly achieving a positive connection, or the shift claws (33, 35) first abut against each other in the form of teeth (58) against gaps (60), and starting from the tooth (58) against tooth (58) abutment, the actuator sleeve (53) is further adjusted until it enters the closed position (II), the spring force tensions the shift claws (33, 35) against each other, and the shift claws (33, 35) are placed in the relative position of teeth (58) against gaps (60) by a small relative angle rotation, so that the shift claws (33, 35) are connected in a positive locking manner when the spring force is reduced.

6. The driving device according to claim 4, characterized in that: The shifting claw on the wheel side is constructed on a supporting ring (41), which is arranged on the first shaft section (17) on the wheel side in a rotationally fixed manner and axially displaceable manner via a plug-in toothing (43). The supporting ring (41) abuts against an axial stop (47) of the first shaft section (17) on the wheel side on its side axially opposite to the second shaft section (19) on the axle side by means of an overload spring (45), and when teeth (58) abut against teeth (58), the actuator sleeve (53) together with the sliding sleeve (37) is adjusted into a closed position (II), so that the sliding sleeve (37) adjusts the supporting ring (41) on the first shaft section (17) on the wheel side by an overload travel (Δh) while generating a spring force.

7. The driving device according to claim 5, characterized in that: The actuator sleeve (53) is mounted on the bearing outer ring (61) of the rotary bearing (57, 59) in an axially movable manner, that is, in a manner that does not transmit an adjusting force, and the bearing inner ring (63) of the rotary bearing (57, 59) is mounted on the sliding sleeve (37) in an axially fixed position and in a manner that cannot rotate relative to each other, that is, in a manner that transmits an adjusting force, and / or an annular gap (71) is provided between the actuator sleeve (53) and the cylindrical outer circumference of the sliding sleeve (55), and the overload spring (45) is arranged in the annular gap. In the shaped gap, and the overload spring (45) is axially supported between the axial stop (73) of the actuator sleeve (53) and the bearing outer ring (61) of the rotary bearing (57, 59), during the closing process, the actuator sleeve (53) and the sliding sleeve (37) are adjusted in a motion-coupled manner until the teeth (58) are in contact with the teeth (58), and starting from the realization of the tooth (58) in contact with the tooth (58), the actuator sleeve (53) is further adjusted in a manner decoupled from the motion of the sliding sleeve (37) until it enters the closed position (II).

8. The driving device according to claim 5, characterized in that: With the formation of a spring force of an overload spring (45) acting axially on the shift claws (33, 35), the actuator sleeve (53) is further displaced starting from the achievement of tooth (58) against tooth (58) until it reaches the closed position (II).

9. The driving device according to claim 7, characterized in that: Under the spring force of the overload spring (45), starting from the contact of the teeth (58) against the teeth (58), the actuator sleeve (53) is displaced in a manner decoupled from the movement of the sliding sleeve (37) until it reaches the closed position (II).

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