DE102024203033B3 - Drive unit for a muscle-powered vehicle and vehicle - Google Patents

Abstract

A drive unit for a vehicle that can be operated using human power has a stationary component (9), a gear unit (10, 20, 30), an electric motor (70) with a rotor (71) and a stator (72), a mechanical drive with an input element (4), and an output element (5). The stator (72) is fastened to the stationary component (9). The input element (4) and the rotor (71) are mechanically operatively connected to the output element (5) via the gear unit (10, 20, 30) for outputting a drive force. The input element (4) extends in an axial direction through the rotor (71) and the output element (5) and is arranged coaxially to the rotor (71) and the output element (5). The rotor (71) is rotatably mounted on the stationary component (9) via a first rotor bearing (51) and a second rotor bearing (52).

Description

The present invention relates to a drive unit for a muscle-powered vehicle and a vehicle having a drive unit.

A drive unit for a human-powered vehicle, such as an e-bike, is known. Such a drive unit can have an electric motor to support a mechanical drive. A rotor of the electric motor can be arranged coaxially with a pedal crankshaft of the mechanical drive. For modern e-bikes, the requirements regarding noise generation are constantly increasing.

JP H11 - 20 772 A relates to a drive unit with a planetary gear and an electric motor for an electric bicycle, which assists the rider's pedaling by generating auxiliary torque via the electric motor. A torque detection system supports the control of the electric motor.

DE 10 2013 016 917 A1 relates to a drive unit for an e-bicycle, comprising an electric motor, three shafts, and three rotational transmission elements. A force acting on one of the shafts is detected by a sensor unit.

DE 10 2022 208 264 B3 relates to a drive device for an e-bicycle, comprising an electric motor, a pedal crankshaft, and an output element. A transmission coupled to the electric motor and the output element is provided, as well as a torque limiting assembly that limits the torque acting on the rotor of the electric motor.

DE 10 2012 109 743 A1 relates to a bicycle drive unit comprising a crankshaft, an engine, a power transmission shaft for transmitting the rotation of the crankshaft, and a power section to which the rotation of the power transmission shaft is transmitted and combined with the power of the engine.

DE 10 2023 201 925 B3 (post-published) relates to a drive device for an e-bicycle, comprising an electric motor, a pedal crankshaft, and an output element. A transmission is provided, which is coupled to the electric motor and the output element, as well as a torque limiting assembly that limits the torque acting on the rotor of the electric motor and, when a maximum torque is exceeded, allows rotation of a support element relative to a stationary element.

JP H10 - 225 053 A relates to a drive device that can transmit a reduced speed of an engine and thereby simplify the structure and reduce the size of a power transmission system.

The object of the present invention is to provide an improved drive unit that enables quiet operation. The present invention achieves this object with subject matter having the features of the independent patent claims. Advantageous further developments are the subject of the dependent claims.

In one aspect, a drive unit for a human-powered vehicle is usable. The vehicle can be formed by an e-bike or a pedelec. The drive unit has a stationary component, a transmission unit, an electric motor with a rotor and a stator, a mechanical drive with an input element, and an output element. The input element can be formed by a pedal crank. The input element can have pedals for absorbing pedaling force from a rider. The stationary component can have at least one of a transmission housing and a housing cover. The output element can have a sprocket or a pulley. The output element can have an output shaft.

The stator is attached to the stationary component. The input element and the rotor are mechanically operatively connected to the output element via the gear unit for outputting a drive force. The gear unit can have a summing gear. The gear unit can have a planetary gear set. The gear unit can have a first planetary gear set, a second planetary gear set, and an output gear. The output gear can be formed by a third planetary gear set. At least one of the first planetary gear set, the second planetary gear set, and the third planetary gear set can be formed by a minus planetary gear set. At least one of the first planetary gear set, the second planetary gear set, and the third planetary gear set can be formed by a plus planetary gear set.

The input element extends in an axial direction through the rotor and the output element. The input element may have an axis of rotation. The axis of rotation may be aligned in the axial direction. A radial direction may be aligned substantially perpendicular to the axial direction. The input element is arranged coaxially with the rotor and the output element. The rotor is rotatably mounted on the stationary component via a first rotor bearing and a second rotor bearing. This means the rotor is supported independently of any deflection of the input element. Rotor gap changes and the associated bearing distortion and noise generation can be avoided. This increases the service life of the drive unit.

If two elements are mechanically operatively connected, they are directly or indirectly coupled to one another in such a way that a movement of one element causes a reaction in the other element. For example, a mechanical operative connection can be provided by a positive or frictional connection. The mechanical operative connection can correspond to the meshing of corresponding toothings of the two elements. Additional elements, such as one or more spur gear stages, can be provided between the elements. A permanently rotationally fixed connection between two elements, on the other hand, is understood to be a connection in which the two elements are rigidly coupled to one another in all intended states of the transmission. The elements can be present as individual components connected to one another in a rotationally fixed manner or as a single piece.

The stationary component can have a projection. The projection can extend in the axial direction. The projection can extend from a first side in the axial direction to a second side. The second side can be a side of the drive unit on which the gear unit is arranged relative to the electric motor. The second side can be arranged opposite the first side relative to the gear unit. The projection can extend at least partially within the rotor. The projection can be hollow on the inside. The input element can extend through the projection. The projection can be designed to support the rotor.

The projection may have a bearing seat for receiving the first rotor bearing. The projection may have a second bearing seat for receiving the second rotor bearing. At least one of the bearing seat for the first rotor bearing and the bearing seat for the second rotor bearing may be formed on an outer periphery of the projection. The bearing seat for the first rotor bearing may be arranged on the first side with respect to the rotor. The bearing seat for the second rotor bearing may be arranged on the second side with respect to the first bearing seat for the first rotor bearing. At least one of the bearing seat for the first rotor bearing and the bearing seat for the second rotor bearing may be arranged radially inside an inner periphery of the rotor or a rotor shaft of the rotor. At least one of the bearing seat for the first rotor bearing and the bearing seat for the second rotor bearing may be arranged axially outside the rotor. The projection may have a stepped portion between the first rotor bearing and the second rotor bearing in the axial direction. The outer diameter of the projection may decrease in the axial direction from the first rotor bearing to the second rotor bearing.

The rotor may include the rotor shaft. The rotor shaft may extend through the rotor in the axial direction. The rotor shaft may form a bearing seat for each of the first rotor bearing and the second rotor bearing. The rotor shaft may form at least one of the bearing seat for the first rotor bearing and the bearing seat for the second rotor bearing on an inner circumference.

The first rotor bearing can form a fixed bearing. The second rotor bearing can form a floating bearing. The first rotor bearing and the second rotor bearing can form an O-arrangement as a bearing arrangement. The second rotor bearing can be secured in the axial direction to the stationary component, for example the projection, via a securing element, for example a snap ring or a retaining ring. The first rotor bearing can be secured in the axial direction to the rotor shaft via a securing element, for example a snap ring or a retaining ring. The stationary component and the rotor shaft can have shoulders for abutting at least one of the first rotor bearing and the second rotor bearing in the axial direction. At least one of the first rotor bearing and the second rotor bearing can be formed by a rolling bearing, for example a ball bearing, a tapered roller bearing, or a needle bearing. At least one of the first rotor bearing and the second rotor bearing can be formed by a radial bearing.

The rotor can be freely rotatable about the input element. The rotor can, for example, rotate about a rotational axis. The rotational axis can be aligned in the axial direction. The input element and the rotor can be designed to be rotatable about the same rotational axis. The input element can be rotatably mounted on the stationary component via a first input bearing. The input element can be rotatably mounted on the output element via a second input bearing. One of the first input bearing and the second input bearing can be formed by a roller bearing, a radial bearing, a needle bearing, a ball bearing, or a deep groove ball bearing. The first input bearing can be arranged in the same plane as the first rotor bearing in the axial direction. The first input bearing can be arranged within the first rotor bearing in the radial direction. The first input bearing may be located on the first side relative to the rotor.

The first planetary gear set may include a first sun gear, a first planet carrier, one or more first planet pinions, one or more first planet gears, and a first ring gear. The second planetary gear set may include a second sun gear, a second planet carrier, one or more second planet pinions, one or more second planet gears, and a second ring gear.

The rotor can be connected to the first sun gear in a rotationally fixed manner. The first sun gear can mesh with the first planet gear. The first planet gear can be mounted on the first planet pin via a bearing, for example a radial bearing, a deep groove ball bearing, a plain bearing, or a needle bearing. The first planet pin can be attached to the first planet carrier, for example, by being pressed into the first planet carrier. The first planet gear can mesh with the first ring gear.

The second sun gear can be connected to the first ring gear in a rotationally fixed manner. A sun ring gear can form the second sun gear on an outer circumference. The sun ring gear can form the first ring gear on an inner circumference. The second sun gear can mesh with the second planet gear. The second planet gear can be mounted on the second planet pin via a bearing, for example a radial bearing, a deep groove ball bearing, a plain bearing or a needle bearing. The second planet pin can be attached to the second planet carrier, for example pressed into the second planet carrier. The second planet gear can mesh with the second ring gear. The second ring gear and the first planet carrier can be connected to an output shaft in a rotationally fixed manner. The second ring gear can be connected to the first planet carrier in a rotationally fixed manner. At least one of the second ring gear and the first planet carrier can be formed by the output shaft.

The second planetary gear set may be arranged offset from the first planetary gear set in the axial direction. The second planetary gear set may overlap the first planetary gear set in the radial direction. The second planetary gear set may be arranged outside the first planetary gear set in a radial direction. The second planetary gear set may be arranged in the same plane as the first planetary gear set in the axial direction. The first and second planetary gear sets may form an eighth gear set. The first and second planetary gear sets may be arranged stacked in the radial direction.

The output transmission may include a third planetary gear set. The third planetary gear set may include at least a third sun gear, a third planet carrier, and a third ring gear. The third planetary transmission may further include a third planetary pinion and a third planetary gear. The third sun gear may mesh with the third planetary gear. The third planetary gear may be rotatably mounted on the third planetary pinion via a bearing, such as a needle bearing. The third planetary pinion may be attached to the third planet carrier. The third planetary gear may mesh with the third ring gear.

An output element, for example the output shaft, of the first planetary gear set and the second planetary gear set can be connected in a rotationally fixed manner to the third sun gear. The output shaft can form the third sun gear on an outer circumference. The third ring gear can be connected in a rotationally fixed manner to the output element.

The first rotor bearing can be arranged at a distance from the second rotor bearing in the axial direction. The first rotor bearing can be arranged at a distance from the second rotor bearing via a spacer sleeve. The spacer sleeve can be arranged at least partially within the rotor or the rotor shaft. The spacer sleeve can be arranged coaxially with the input element and the rotor.

In one embodiment of the drive unit, the first rotor bearing can be arranged offset in the axial direction from the rotor, for example outside the rotor. The second rotor bearing can be arranged in the axial direction in the same plane as the rotor. The second rotor bearing can be arranged inside the rotor in the axial direction. The second rotor bearing can be arranged inside the rotor in the radial direction. The first rotor bearing can be arranged on the first side. The first rotor bearing can be arranged offset from the first side with respect to the rotor. An outer circumference of the first rotor bearing can be arranged outside an inner circumference of the rotor in the radial direction. The first rotor bearing can be arranged outside an inner circumference of the rotor in the radial direction.

In one embodiment of the drive unit, the first rotor bearing can be formed by a ball bearing. The first rotor bearing can be a fixed bearing. The first rotor bearing can position the rotor in the axial direction. The first rotor bearing can be formed by a deep groove ball bearing.

In one embodiment of the drive unit, the second rotor bearing can be a needle bearing The second rotor bearing may have an inner ring. The inner ring may be attached to the bearing seat for the second rotor bearing in the stationary component. The stationary component may then be made of a lightweight material, such as aluminum.

The inner ring can be pressed onto the bearing seat for the second rotor bearing. The inner ring can be secured in the axial direction by a securing element, for example a retaining ring or a snap ring. Rolling elements of the second rotor bearing can be in contact with an inner circumference of the rotor or the rotor shaft. The second rotor bearing, designed as a needle bearing, can have a small outer diameter compared to a ball bearing. This allows an inner circumference, for example an inner diameter of the rotor, to be designed small. This allows the drive unit to be designed compactly in the radial direction.

In one embodiment of the drive unit, an outer circumference of the second rotor bearing can be smaller in a radial direction than an outer circumference of the first rotor bearing. The bearing seat of the rotor shaft for the second rotor bearing can be arranged radially within the bearing seat of the rotor shaft for the first rotor bearing. The second rotor bearing can be arranged radially within the first rotor bearing and spaced apart from the first rotor bearing in the axial direction.

The drive unit has a rotor position sensor, which is arranged radially outside the first rotor bearing and axially in the same plane as the first rotor bearing. An element of the rotor position sensor can be connected to the rotor in a rotationally fixed manner. An element of the rotor position sensor can be connected to the stationary component in a rotationally fixed manner. This allows the rotation angle and rotational speed of the rotor to be determined.

• 1 zeigt eine Schnittansicht einer Ausführungsform einer Antriebseinheit.
• 2 zeigt eine Schnittansicht einer weiteren Ausführungsform der Antriebseinheit.
• 3 zeigt eine Schnittansicht einer weiteren Ausführungsform der Antriebseinheit.

In one aspect, a vehicle has at least one drive wheel and a drive unit according to one of the preceding embodiments. The vehicle can be operated using muscle power. The vehicle can be provided by an e-bike or a pedelec. The drive wheel is mechanically operatively connected to the drive unit via the output element such that the drive unit can propel the vehicle. The vehicle can have other devices such as a braking device or a steering device. The vehicle can have a user interface for user input.

• 1 shows a sectional view of an embodiment of a drive unit.
• 2 shows a sectional view of another embodiment of the drive unit.
• 3 shows a sectional view of another embodiment of the drive unit.

1 shows a sectional view of an embodiment of a drive unit. The drive unit can be used for a muscle-powered vehicle, in this case an e-bike. The drive unit has a stationary component 9, in this case a transmission housing, a transmission unit 10, 20, 30, an electric motor 70 with a rotor 71 and a stator 72, a mechanical drive with an input element 4, in this case a pedal crankshaft, and an output element 5, in this case a sprocket.

The stator 72 is attached to the stationary component 9. The input element 4 and the rotor 71 are mechanically operatively connected to the output element 5 via the gear unit 10, 20, 30 for outputting a drive force. This allows the mechanical drive to be assisted by the electric motor 70 to propel the vehicle. The input element 4 extends in an axial direction through the rotor 71 and the output element 5. The input element 4 is arranged coaxially to the rotor 71 and the output element 5. The rotor 71 is rotatably mounted on the stationary component 9 via a first rotor bearing 51, in this case a deep groove ball bearing, and a second rotor bearing 52, in this case a deep groove ball bearing. The rotor 71 is not mounted on the input element 4. As a result, the rotor 71 is mounted independently of any deflection of the input element 4. This prevents a change in the rotor gap and the associated bearing preload and noise generation.

Further details of the drive unit are described below.

The electric motor 70 is arranged relative to the gear unit 10, 20, 30 on a first side, the left side in 1 , arranged. The first rotor bearing 51 is arranged on the first side with respect to the rotor 71. The first rotor bearing 51 is arranged spaced apart from the rotor 71 in the axial direction. The second rotor bearing 52 is arranged in the axial direction to a second side, the right side in 1 , offset from the first rotor bearing 51. The second rotor bearing 52 is arranged in the radial direction and in the axial direction within the rotor 71.

The rotor 71 has a rotor shaft. The rotor 71 is attached to an outer circumference of the rotor shaft. The rotor shaft forms a bearing seat for the first rotor bearing 51 on an inner circumference. The rotor shaft forms a bearing seat for the first rotor bearing 51 in the axial direction within of the rotor 71, a bearing seat for the second rotor bearing 52 is provided on an inner circumference. An outer diameter of the first rotor bearing 51 is larger than an outer diameter of the second rotor bearing 52. As a result, the second rotor bearing 52 is arranged radially within the outer diameter of the first rotor bearing 51. Likewise, an outer diameter of the bearing seat for the second rotor bearing 52 is arranged radially within the outer diameter of the bearing seat for the first rotor bearing 51. A rotor position sensor 8 is arranged in the same plane as the first rotor bearing 51 in the axial direction and outside the first rotor bearing 51 in the radial direction.

The stationary component 9 has a projection 91 that extends from the first rotor bearing 51 to the second rotor bearing 52 in the axial direction. The projection 91 extends within the rotor shaft. The projection 91 forms a bearing seat for the first rotor bearing 51 and the second rotor bearing 52 on an outer circumference. An outer circumference of the bearing seat of the projection 91 for the first rotor bearing 51 is larger than an outer circumference of the bearing seat of the projection 91 for the second rotor bearing 52. The projection 91 has a shoulder on the bearing seat for the first rotor bearing 51 on the first side for the first rotor bearing 51 to bear against. The projection 91 has a securing element, in this case a snap ring, on the bearing seat for the second rotor bearing 52 on the second side for the second rotor bearing 52 to bear against in the axial direction. The bearing arrangement comprising the first rotor bearing 51 and the second rotor bearing 52 thus forms an O-arrangement. Furthermore, the rotor shaft has a securing element, in this case a snap ring, on the bearing seat for the first rotor bearing 51 on the first side of the first rotor bearing 51 and a shoulder on the second side of the first rotor bearing 51 for positioning the rotor shaft relative to the first rotor bearing 51.

The projection 91 has, on an inner circumference, a bearing seat for an input bearing for supporting the input element 4. The bearing seat for the input bearing is arranged in the same plane as the first rotor bearing 51 in the axial direction and within the first rotor bearing 51 in the radial direction. The projection 91 has a stepped portion between the first rotor bearing 51 and the second rotor bearing 52, wherein the outer diameter of the projection 91 decreases from the first rotor bearing 51 to the second rotor bearing 52.

2 shows a sectional view of another embodiment of the drive unit. The present embodiment differs from the previous embodiment in the bearing arrangement of the first rotor bearing 51 and the second rotor bearing 52. In this case, the second rotor bearing 52 is designed as a needle bearing with an inner ring. A spacer sleeve is arranged between the first rotor bearing 51 and the second rotor bearing 52, which spacer sleeve positions the second rotor bearing 52 at a distance from the first rotor bearing 51 in the axial direction. The first rotor bearing 51 forms a fixed bearing, and the second rotor bearing 52 forms a loose bearing. As a result, the outer diameter of the second rotor bearing 52 can be designed small, and the drive unit can be designed compactly in the radial direction.

3 shows a sectional view of another embodiment of the drive unit. The present embodiment has all the features of the 1 described embodiment. The transmission unit 10, 20, 30 comprises a first planetary gear set 10, a second planetary gear set 20, and an output gear 30, in this case a third planetary gear set. The drive unit comprises a second electric motor 80.

The first planetary gear set 10 includes a first sun gear 11, a first planet carrier 12, a number of first planet pinions 13, a number of first planet gears 14, and a first ring gear 15. The second planetary gear set 20 includes a second sun gear 21, a second planet carrier 22, a number of second planet pinions 23, a number of second planet gears 24, and a second ring gear 25. The output gear 30 includes the third sun gear 31, a third planet carrier 32, a number of third planet pinions 33, a number of third planet gears 34, and a third ring gear 35.

The rotor 71 is rotationally fixedly connected to the first sun gear 11. The first planetary gear set 10 is arranged radially within the second planetary gear set 20. The first planetary gear set 10 and the second planetary gear set 20 are arranged in the same plane axially.

The first sun gear 11 meshes with the first planet gears 14. Each of the first planet gears 14 is mounted on one of the first planetary pins 13 via a bearing, in this case a needle bearing. The first planetary pins 13 are fastened to the first planetary carrier 12. The first planetary gears 14 mesh with the first ring gear 15. A sun ring gear forms the first ring gear 15 on an inner circumference and the second sun gear 21 on an outer circumference. As a result, the first ring gear 15 is connected to the second sun gear 21 in a rotationally fixed manner.

The second sun gear 21 meshes with the second planet gears 24. Each of the second planet gears 24 is connected via a bearing, in this case a Needle bearings are mounted on one of the second planetary pins 23. The second planetary pins 23 are attached to the second planetary carrier 22. The second planetary carrier 22 is formed by the stationary component 9. The second planetary gears 24 mesh with the second ring gear 25. The second ring gear 25 and the first planetary carrier 12 are connected in a rotationally fixed manner to an output shaft 7. As a result, the second ring gear 25 is connected in a rotationally fixed manner to the first planetary carrier 12. The output shaft 7 is connected in a rotationally fixed manner to the third sun gear 31 of the output gear 30.

The third sun gear 31 meshes with the third planet gears 34. Each of the third planet gears 34 is mounted on one of the third planetary pinions 33 via a bearing, in this case a needle bearing. The third planetary pinions 33 are fastened to the third planetary carrier 32. The third planetary gears 34 mesh with the third ring gear 35. The third ring gear 35 is rotationally fixedly connected to the output element 5. The third ring gear 35 has a toothing 36 on an outer circumference, via which the second electric motor 80 is mechanically operatively connected to the third ring gear 35 via a transmission gear for outputting a drive force.

Reference symbol

4

Input element

5

Output element

7

Output shaft

8

Rotor position sensor

9

Stationary component

10

First planetary gear set

11

First sun wheel

12

First planetary carrier

13

First planetary bolt

14

First planetary gear

15

First ring gear

20

Second planetary gear set

21

Second sun gear

22

Second planet carrier

23

Second planetary bolt

24

Second planetary gear

25

Second ring gear

30

Output gear

31

Third sun gear

32

Third planet carrier

33

Third planetary bolt

34

Third planetary gear

35

Third ring gear

36

Gearing

51

First rotor bearing

52

Second rotor bearing

70

electric motor

71

rotor

72

stator

80

Second electric motor

91

projection

Claims (6)

A drive unit for a muscle-powered vehicle, the drive unit comprising a stationary component (9), a gear unit (10, 20, 30), an electric motor (70) with a rotor (71) and a stator (72), a mechanical drive with an input element (4), and an output element (5), wherein - the stator (72) is fastened to the stationary component (9), - the input element (4) and the rotor (71) are mechanically operatively connected to the output element (5) via the gear unit (10, 20, 30) for outputting a drive force, - the input element (4) extends in an axial direction through the rotor (71) and the output element (5) and is arranged coaxially to the rotor (71) and the output element (5), and - the rotor (71) is rotatably mounted on the stationary component (9) via a first rotor bearing (51) and a second rotor bearing (52). is mounted, characterized in that the drive unit has a rotor position sensor (8) which is arranged in the radial direction outside the first rotor bearing (51) and in the axial direction in the same plane as the first rotor bearing (51). Drive unit according to Claim 1 , characterized in that the first rotor bearing (51) is arranged offset in the axial direction to the rotor (71) and the second rotor bearing (52) is arranged in the axial direction in the same plane as the rotor (71). Drive unit according to one of the preceding claims, characterized in that the first rotor bearing (51) is formed by a ball bearing. Drive unit according to one of the preceding claims, characterized in that the second rotor bearing (52) is formed by a needle bearing. Drive unit according to one of the preceding claims, characterized in that an outer circumference of the second rotor bearing (52) is smaller than an outer circumference of the first rotor bearing (51). A vehicle with at least one drive wheel and a drive unit according to one of the preceding claims, wherein - the vehicle is operable using muscle power, and - the drive wheel is mechanically operatively connected to the drive unit via the output element (5) such that the drive unit can propel the vehicle.

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