DE102022004587B3 - Electric wheel hub drive for a motor vehicle - Google Patents

Abstract

The invention relates to an electric wheel hub drive (1) for a motor vehicle with a wheel carrier (2), with a wheel bearing (29) which has a first bearing ring (31) connected to the wheel carrier (2) in a rotationally fixed manner and a second bearing ring (32) arranged to rotate with respect to a main axis of rotation (A), with an electric machine (3) which has a stator (4) and a rotor (5) arranged to rotate about the main axis of rotation (A), with a stator carrier (6) which is connected to the wheel carrier (2) in a rotationally fixed manner, with a rotor carrier (7) which is connected to the rotor (5) in a rotationally fixed manner and is mounted so as to be rotatable relative to the wheel carrier (2), wherein a separating clutch (13) has a first coupling half (46) connected to the rotor carrier (7) in a rotationally fixed manner and a second coupling half (47) connected to the second bearing ring (32) in a rotationally fixed manner, wherein a servomotor (12) of an actuator of the separating clutch (13) is mounted on one of the first and second coupling halves (46, 47) facing away from the wheel carrier (2).

Description

The invention relates to an electric wheel hub drive for a motor vehicle according to the preamble of claim 1.

In an electric wheel hub drive for a motor vehicle, a disconnect unit can be used. For example, a servomotor is used to actuate the separating clutch. There is little space available for integrating the servomotor into the wheel. In addition, the servomotor is difficult to access when positioned in the wheel, for example for maintenance purposes.

US 2020/0 287 495 A1 describes a control device for an electric motor with a first set of coil windings arranged to form a first sub-motor and a second set of coil windings arranged to form a second sub-motor, wherein the current flow in the first set of coil windings is controlled using a first pulse width modulation (PWM) with a first switching sequence and the current flow in the second set of coil windings is controlled using a second PWM with a second switching sequence, the control device comprising means, arranged to measure the current flow in each of the first set of coil windings, wherein after determining that the sum of the current flow in the first set of coil windings is substantially non-zero, the first PWM values are derived from voltage values which be used to generate the second PWM.

Furthermore, from the JP 2020 - 128 134 A as well as the DE 10 2022 000 035 A1 Wheel hub drives are known, in which a separating clutch is also provided, which has a first clutch half connected in a rotationally fixed manner to a rotor carrier and a second clutch half connected in a rotationally fixed manner to a rim, with a servomotor of an actuator of the separating clutch being arranged directly on the wheel carrier.

The invention is based on the object of specifying a novel electric wheel hub drive for a motor vehicle.

The object is achieved according to the invention by an electric wheel hub drive for a motor vehicle with the features of claim 1.

Advantageous embodiments of the invention are the subject of the subclaims.

In the context of the present application, the term "rotationally fixed" is used as follows: Two elements are connected to each other in a rotationally fixed manner if they are arranged coaxially to one another (with respect to their axis of rotation or with respect to an axis of rotational symmetry) and if they are connected to one another in such a way that they are always rotate at the same angular speed. An element is non-rotatably connected to a housing if it cannot be rotated relative to the housing.

In the context of the present application, the term “radially overlapping” is used as follows: Two (in particular essentially rotationally symmetrical) elements are arranged in a radially overlapping manner with respect to a common axis if they are at least partially in a region of the same radial coordinates (in particular and the same Angular coordinates) are arranged.

In the context of the present application, the term “axially overlapping” is used as follows: Two elements are arranged axially overlapping with respect to a common axis if they are each at least partially arranged in a region of the same axial coordinates.

In the context of the present application, the term “radially within” is used as follows: A first element is arranged radially within a second element with respect to a common axis if the first element is arranged in a region of smaller radii than the second element.

According to the invention, an electric wheel hub drive for a motor vehicle is proposed, with a wheel carrier, with a rim, with a wheel bearing which has a first bearing ring connected to the wheel carrier in a rotationally fixed manner and a second bearing ring arranged to rotate with respect to a main axis of rotation, with an electric machine which has a stator and a rotor arranged to rotate about the main axis of rotation, with a stator carrier which is connected to the wheel carrier in a rotationally fixed manner, with a rotor carrier which is connected to the rotor in a rotationally fixed manner and is mounted so as to rotate relative to the wheel carrier. A separating clutch is provided which has a first coupling half connected to the rotor carrier in a rotationally fixed manner and a second coupling half connected to the rim in a rotationally fixed manner, with a servomotor of an actuator of the separating clutch being arranged directly on the wheel carrier. This makes it possible to produce a particularly compact wheel hub drive, while at the same time providing good access to the servomotor for maintenance purposes.

Particularly advantageous is the actuator on one of the first and second coupling halves facing side of the wheel carrier, whereby the servo motor is partially arranged in a recess provided for this purpose in the wheel carrier.

In a manner known per se, an axis of rotation of the servomotor is arranged parallel to the main axis of rotation.

The servomotor has a shaft which is connected in a rotationally fixed manner to a rotor of the servomotor. According to the invention, the wheel carrier has a bore, the shaft being guided through the bore.

The stator carrier particularly advantageously has a plate section which is arranged on a side of the wheel carrier facing away from the servomotor, the plate section having a passage through which the shaft is guided.

In one embodiment, the actuator has an axial displacement device which is arranged on a side of the wheel carrier facing away from the servo motor and is designed to convert a rotational movement of the shaft into an axial movement parallel to the main axis of rotation.

In one embodiment, the axial displacement device has a pinion which is connected to the shaft in a rotationally fixed manner.

In one embodiment, the axial displacement device has a first ramp ring coupled to the pinion via a tooth engagement and a second ramp ring connected to the stator carrier in a rotationally fixed manner via a groove in the stator carrier.

In one embodiment, a cover is arranged over the servomotor on the side facing away from the wheel carrier.

In one embodiment, the second ramp ring has a shift fork which engages in the sliding sleeve, so that the sliding sleeve can be moved axially together with the second ramp ring, but rotation of the sliding sleeve together with the rotor carrier is possible independently of the second ramp ring.

In one embodiment, the first ramp ring has a ramp that engages with a counter ramp of the second ramp ring, so that rotation of the first ramp ring causes axial movement of the second ramp ring.

A separating clutch in the sense of the present invention comprises two coupling halves (for example as a claw clutch or positive clutch; alternatively, a multi-plate clutch or a friction clutch can also be used). The term “disconnecting clutch” can also include a sliding sleeve, whereby the second coupling half of the separating clutch can be designed, for example, as gaps and/or holes in the brake disc carrier. However, the second coupling half can also be designed as a separate claw toothing, which is also connected to the second bearing ring in a rotationally fixed manner.

The term “actuator of the separating clutch” includes all components that are located upstream of the sliding sleeve: servomotor, adjusting shaft, pinion, axial displacement device (having the pinion, a first ramp ring, a second ramp ring, possibly balls in between).

The actuator can be shielded by a protective device, for example a cover, to protect it from stone chips and environmental influences.

A small servomotor in the wheel carrier results in weight and package advantages compared to a large ring motor in the drive module.

Exemplary embodiments of the invention are explained in more detail below with reference to drawings.

• 1 eine schematische Ansicht eines elektrischen Radnabenantriebs für ein Kraftfahrzeug, und
• 2 eine schematische Detailansicht des elektrischen Radnabenantriebs.

Show:

• 1 a schematic view of an electric wheel hub drive for a motor vehicle, and
• 2 a schematic detailed view of the electric wheel hub drive.

Corresponding parts are provided with the same reference numbers in all figures.

1 shows a schematic view of an electric wheel hub drive 1 for a motor vehicle with a wheel carrier 2, with an electric machine 3, which has a stator 4 and a rotor 5 arranged rotatably about a main axis of rotation A, with a stator carrier 6, which is connected to the wheel carrier 2 in a rotationally fixed manner is, with a rotor carrier 7, which is rotatably connected to the rotor 5 and rotatably mounted relative to the wheel carrier 2, the stator carrier 6 having a plate section 8 and a cylinder section 9, the cylinder section 9 being arranged radially outside the plate section 8. The plate section 8 has a first passage 10 for a shaft 11 of a servomotor 12 of a separating clutch 13, the separating clutch 13 is arranged radially within the cylinder section 9.

In the in 1 In the embodiment shown, the plate section 8 has second bushings 14 for screw connections 15, which are designed to connect the plate section 8 to the wheel carrier 2 in a rotationally fixed manner.

In the embodiment, the second feedthroughs 14 are arranged essentially in an area with the same radii as the first feedthrough 10.

In the embodiment, the cylinder section 9 has at least one channel 16, which is designed to receive a coolant.

In the embodiment, a rotor bearing 17 is provided for the rotary mounting of the rotor 5 and is arranged radially within and axially overlapping the channel 16.

In the embodiment, the separating clutch 13 further has a second ramp ring 18 arranged radially within the cylinder section 9, the second ramp ring 18 being connected to the cylinder section 9 in a rotationally fixed manner and being axially displaceable relative to the cylinder section 9.

In the embodiment, the cylinder section 9 has at least one groove 19 on its radially inner side, which runs parallel to the main axis of rotation A, the ramp ring 18 being connected to an engagement element 20 which engages in one of the grooves 19.

In one embodiment, the cylinder section 9 has a sealing surface for a seal 21, in particular a radial seal, on its radially outer side relative to the rotor carrier 7.

In one embodiment, the sealing surface is arranged axially between the stator 4 and a brake disk 22.

The rotor bearing 17 is part of a combined bearing 28, which further includes a wheel bearing 29, the combined bearing 28 having an outer bearing shell 30, a middle bearing shell 31 and an inner bearing shell 32, with between the outer bearing shell 30 and the middle bearing shell 31, which form the rotor bearing 17, a plurality of rolling elements 33 are arranged, with a plurality of rolling elements 33 being arranged between the middle bearing shell 31 and the inner bearing shell 32, which form the wheel bearing 29.

The brake disc 22 can be designed as an inside-out brake disc and arranged on a brake disc carrier 23, which is connected to a rim 24 in a rotationally fixed manner. The rim 24 and the brake disc carrier 23 are connected in a rotationally fixed manner to the inner bearing shell 32 of the wheel bearing 29 via several wheel bolts 27.

Another radial seal 25 can be arranged between the brake disc carrier 23 and the rotor carrier 7.

The second ramp ring 18 is axially fixedly connected to a shift fork 50, which engages in a groove of a first clutch half 46.

A pinion 34 is also arranged on the shaft 11 and is in an operative connection with the second ramp ring 18 via a first ramp ring 35. The first ramp ring 35 has a toothing on an inner circumference, which is in engagement with a pinion toothing of the pinion 34. The first ramp ring is arranged coaxially to the main axis of rotation A. A corresponding rotation of the pinion 34 causes a rotation of the first ramp ring 35 about the main axis of rotation A. A first ramp, not shown, of the first ramp ring 35 consequently causes an axial displacement of the second ramp ring in the direction of the coupling halves 46, 47.

A brake caliper 38 with brake blocks 39 is also arranged on the wheel carrier 2. The brake caliper 38 can be designed as an internal brake caliper 38.

The wheel carrier 2, the brake caliper 38, the brake pads 39, the stator 4, the stator carrier 6, the servomotor 12, the shaft 11, the pinion 34 and the middle bearing shell 31 do not rotate with the rim 24.

The brake disc 22, the brake disc carrier 23 and the inner bearing shell 32 always rotate together with the rim 24.

The rotor carrier 7, the rotor 5, the first clutch half 46, the ramp ring 18, the engagement element 20 and the outer bearing shell 30 only rotate with the rim 24 when the separating clutch 13 is connected.

The electrical machine 3 can be designed as an axial flux machine.

To seal a rotor space, in particular a space between the rotor 5 and the stator 4, a first seal 21 can be provided, which is arranged coaxially to the rotor carrier 7, such that a first intermediate gap between the rotor carrier 7 and the Stator carrier 6 is filled by the first seal 21.

A second seal 25 or further radial seal 25 can be arranged coaxially with the rotor carrier 7, such that a second intermediate gap between the rotor carrier 7 and the brake disc carrier 23 is filled by the second seal 25.

With regard to the main axis of rotation A, the second seal 25 can be arranged axially on a side of the first seal 21 facing away from the wheel carrier 2.

The second seal 25 can be arranged radially within the stator 4, that is to say in particular radially within the area of magnets arranged in the stator 4.

The first seal 21 can be arranged radially within the rotor 5, that is to say in particular radially within the area of magnets arranged in the rotor 5.

A first connection point for connecting the brake disc carrier 23 to the inner bearing shell 32 can be arranged radially within the second seal 25.

The brake disc 22, which is non-rotatably connected to the brake disc carrier 23, can be arranged axially on a side of the first seal 21 opposite the second seal 25 with respect to the main axis of rotation A.

Furthermore, a third seal 40 can be arranged coaxially with the rotor carrier 7, such that a third intermediate gap between the middle bearing shell 31, which can also be referred to as the first bearing ring, and the inner bearing shell 32, which can also be referred to as the second bearing ring, is filled by the third seal 40.

Furthermore, there can be a second connection point for the tight connection of the middle bearing shell 31 to the stator carrier 6. This completes the rotor space: the stator carrier 6 has the cylinder section 9, which is sealed by means of the first seal 21 relative to a first disk-shaped part 41 of the rotor carrier 7, which lies on one side of the stator 4 when viewed axially. The rotor carrier 7 also has a cylindrical part 42 and a second disk-shaped part 43 connected to the cylindrical part 42 and which is sealed from the brake disk carrier 23 by means of the second seal 25. The brake disc carrier 23 has a tight connection point to the inner bearing shell 32. The inner bearing shell 32 is sealed from the middle bearing shell 31 by means of the third seal 40. The middle bearing shell 31 has the tight second connection point to the stator carrier 6.

Furthermore, a fourth seal 44 can be provided between the inner bearing shell 32 and the middle bearing shell 31 on the side of the wheel bearing 29 axially opposite the third seal 40.

The middle bearing shell 31 can be designed as a single, one-piece bearing shell, which is both a radially outer part of the wheel bearing 29 and a radially inner part of the rotor bearing 17. Alternatively, the middle bearing shell 31 can also be designed as two bearing shells connected to one another in a rotationally fixed manner, one of which is a radially outer part of the wheel bearing 29 and the other is a radially inner part of the rotor bearing 17.

2 is a schematic detailed view of the electric wheel hub drive 1.

The separating clutch 13 has the first clutch half 46 which is non-rotatably connected to the rotor carrier 7. Furthermore, the separating clutch 13 has a second coupling half 47 which is connected in a rotationally fixed manner to the second bearing ring 32, with a servomotor 12 of the separating clutch 13 being arranged directly on the wheel carrier 2. The servomotor 12 can be arranged on a side of the wheel carrier 2 facing away from the first and second coupling halves 46, 47.

An axis of rotation B of the shaft 11 is arranged parallel to the main axis of rotation A.

The shaft 11 is connected in a rotationally fixed manner to a servomotor rotor of the servomotor 12. The wheel carrier 2 has in the exemplary embodiment 1 a hole 48, the shaft 11 being passed through the hole 48.

The plate section 8 is advantageously arranged on a side of the wheel carrier 2 facing away from the servomotor 12, the plate section 8 having the passage 10 through which the shaft 11 is guided.

An axial displacement device 26 is arranged on a side of the wheel carrier 2 facing away from the servomotor 12. The axial displacement device 26 is designed to convert a rotational movement of the shaft 11 into an axial movement parallel to the main axis of rotation A.

The axial displacement device 26 includes the pinion 34, which is connected to the shaft 11 in a rotationally fixed manner. The axial displacement Direction 26 further includes the first ramp ring 35 and the second ramp ring 18.

The second ramp ring 18 has a shift fork 50 which engages in a groove of the first clutch half 46, so that the first clutch half can rotate together with the rotor carrier 7, while the second ramp ring 18 does not rotate, but the first clutch half 46 rotates together with the second ramp ring 18 can be moved axially.

Turning the shaft 11 causes the first ramp ring 35 to rotate via the pinion 34 and the toothing, which causes an axial movement of the second ramp ring 18 and the first coupling half 46. Depending on the direction of rotation of the shaft 11, this moves into the second coupling half 47 and thus couples the rotor carrier 7 with the brake disk carrier 23 or decouples the rotor carrier 7 from the brake disk carrier 23. A disengagement movement of the first coupling half 46 can, for example, be achieved by acting in the axial direction Spring, which is not shown here, can be done or supported.

A cover 49 can be arranged above the servomotor 12.

The first coupling half 46 is connected to the rotor carrier 7 in a rotationally fixed manner, since in the exemplary embodiment the first coupling half 46 engages through bushings 37 in the rotor carrier 7. The first coupling half 46 is arranged circularly and coaxially to the main axis of rotation A in the area of engagement of the shift fork 50. The first coupling half 46 advantageously has a claw toothing which passes through the rotor carrier 7. The claw teeth of the first coupling half 46 advantageously fits into another claw toothing, which is part of the second coupling half 47.

The first ramp ring 35 and the second ramp ring 18 are advantageously arranged radially within the cylinder section 9.

The components of the separating clutch 13, which are effectively positioned upstream of the first clutch half 46, that is to say the servomotor 12, the shaft 11, the pinion 34 and the axial displacement device (having the pinion 34, the first ramp ring 35, the second ramp ring 18, if necessary between the Ramp rings 35, 18 lying balls), can together be referred to as an actuator.

Reference symbol list

1

electric wheel hub drive

2

Wheel carrier

3

electric machine

4

stator

5

rotor

6

Stator carrier

7

Rotor carrier

8th

plate section

9

Cylinder section

10

execution

11

Wave

12

Servomotor

13

Separating clutch

14

execution

15

screw connection

16

channel

17

Rotor bearing

18

Ramp ring

19

Groove

20

Intervening element

21

Seal, first seal

22

Brake disc

23

Brake disc carrier

24

rim

25

another radial seal, second seal

26

Axial displacement device

27

Wheel bolt

28

combined warehouse

29

Wheel bearing

30

outer bearing shell

31

middle bearing shell, first bearing ring

32

inner bearing shell, second bearing ring

33

rolling elements

34

pinion

35

Ramp ring

37

execution

38

caliper

39

Brake pad

40

third seal

41

first disc-shaped part

42

cylindrical part

43

second disc-shaped part

44

fourth seal

46

Coupling half

47

Coupling half

48

drilling

49

cover

50

Shift fork

A

Main axis of rotation

b

Axis of rotation

Claims (8)

Electric wheel hub drive (1) for a motor vehicle with a wheel carrier (2), with a rim (24) with a wheel bearing (29), which has a first bearing ring (31) connected in a rotationally fixed manner to the wheel carrier (2) and a rotatable to a main axis of rotation ( A) arranged second bearing ring (32), with an electrical machine (3), which has a stator (4) and a rotor (5) arranged rotatably about the main axis of rotation (A), with a stator carrier (6), which is rotationally fixed the wheel carrier (2), with a rotor carrier (7), which is non-rotatably connected to the rotor (5) and rotatably mounted relative to the wheel carrier (2), with a separating clutch (13), which is non-rotatably connected to the rotor carrier (7 ) connected first coupling half (46) and a second coupling half (47) connected in a rotationally fixed manner to the rim (24), a servomotor (12) of an actuator of the separating clutch (13) being arranged directly on the wheel carrier (2), with an axis of rotation (B) a shaft (11) of the servomotor (12) is arranged parallel to the main axis of rotation (A), characterized in that the wheel carrier (2) has a bore (48), the shaft (11) passing through the bore (48 ) is passed through. Electric wheel hub drive (1). Claim 1 , characterized in that the stator carrier (6) has a plate section (8) which is arranged on a side of the wheel carrier (2) facing away from the servomotor (12), the plate section (8) having a passage (10) through which the shaft (11) is passed through. Electric wheel hub drive (1) according to Claim 1 or 2 , characterized in that the actuator has an axial displacement device (26) which is arranged on a side of the wheel carrier (2) facing away from the servomotor (12) and is designed to convert a rotary movement of the shaft (11) into an axial movement parallel to the main axis of rotation (A). Electric wheel hub drive (1). Claim 3 , characterized in that the axial displacement device has a pinion (34) which is connected to the shaft (11) in a rotationally fixed manner. Electric wheel hub drive (1). Claim 4 , characterized in that the axial displacement device (26) has a first ramp ring (35) which is coupled to the pinion (34) via a tooth engagement and a second ramp ring which is connected in a rotationally fixed manner to the stator carrier (6) via a groove (19) in the stator carrier (6). 18). Electric wheel hub drive (1) according to one of the preceding claims, characterized by a cover (49) which is arranged above the servomotor (12) on the side facing away from the wheel carrier (2). Electric wheel hub drive (1). Claim 5 , characterized in that the second ramp ring (18) has a shift fork (50) which engages in a groove in the first coupling half (46), so that the first coupling half (46) can be moved axially together with the second ramp ring (18). . Electric wheel hub drive (1). Claim 5 , characterized in that the first ramp ring (35) has a ramp which is in engagement with a counter ramp of the second ramp ring (18), so that rotation of the first ramp ring (35) causes an axial movement of the second ramp ring (18).

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