Gearbox, drive unit with such a gearbox and vehicle with drive unit

Abstract

A transmission has a first planetary gear set (10) which has at least a first sun gear (11), a first planet carrier (12), and a first ring gear (15), and a second planetary gear set (20) which has at least a second sun gear (21), a second planet carrier (22), and a second ring gear (25). The first sun gear (11) is designed to input a drive force into the transmission. The first planet carrier (12) and the second ring gear (25) are designed to output a drive force from the transmission. The first ring gear (15) is connected in a rotationally fixed manner to the second sun gear (21). The first planet carrier (12) is rotatably mounted on the second planet carrier (22) via a transmission bearing (45) designed to support a radial force, wherein the transmission bearing (45) is formed by a radial bearing.

Description

[0001] The present invention relates to a transmission, a drive unit with a transmission and a vehicle with a drive unit.

[0002] A transmission with multiple planetary gear sets, for example, for a human-powered vehicle such as an e-bike, is well known. Bearings for the gear set elements of the planetary gear sets are of great importance for achieving targeted movement of the gear set elements and preventing wear on the gear set elements.

[0003] EP 3 188 957 B1 discloses a drive train for a bicycle, the drive train comprising a first and a second motor and a planetary gear having a planet carrier, a gear ring and a sun gear, the first motor being connected to the planetary gear, the drive train also comprising a crank axle to which the gear ring is connected to establish a first input to the planetary gear, the second motor being mechanically coupled to the crank axle and the first motor being connected to the sun gear, the planet carrier being connected to an output chainring of the drive train.The first and second motors are each equipped with one or more first or one or more second sensors designed to measure the angular position of the rotor on the motor to which they are assigned, the first and second sensors being connected to a control unit, the drive train comprising measuring elements designed to generate current measurement signals indicating the torque delivered by the first motor and the torque delivered by the second motor, the control unit being designed to control the first motor according to an angular position setpoint and the second motor according to a current or torque setpoint.

[0004] DE 10 2020 000 661 A1 discloses an electric drive device for a motor vehicle. DE 10 2017 006 266 A1 discloses a transmission device for an electric drive of a motor vehicle and an electric drive for a motor vehicle. A drive train for a bicycle is disclosed in DE 10 2023 201 653 A1 and DE 10 2023 201 654 A1. DE 10 2016 225 159 A1 discloses a transmission for a bicycle, comprising an output shaft, a gearbox that is operatively connectable to a bottom bracket crankshaft and that is operatively connected or operatively connectable to the output shaft, and an electric machine that is operatively connected or operatively connectable to the output shaft.

[0005] Based on this, it is the object of the present invention to provide an improved transmission that is compact in design and has an increased service life. This object is achieved by the subject matter having the features of the independent patent claims. Advantageous further developments are the subject matter of the dependent claims.

[0006] A transmission can be used for a vehicle. The vehicle can be designed as a bicycle, an e-bike, a cargo bike, or a pedelec. The vehicle can have a drive unit with the transmission. The drive unit can have a first electric motor. The first electric motor can have a first rotor and a first stator. The transmission has a first planetary gear set, which has at least a first sun gear, a first planet carrier, and a first ring gear. The first planetary gear set can further have one or more first planet pins and one or more first planet gears. The first electric motor can be arranged coaxially to the first sun gear. The transmission has a second planetary gear set, which has at least a second sun gear, a second planet carrier, and a second ring gear. The second planetary gear set can further have one or more second planet pins and one or more second planet gears.

[0007] The first sun gear is configured to input a drive force into the transmission. The first sun gear can be mechanically operatively connected to the rotor. The first sun gear can be connected in a rotationally fixed manner to the rotor. The first sun gear can be arranged coaxially to the rotor. The rotor can form an axis of rotation. The axis of rotation can be aligned in an axial direction. A radial direction can be arranged substantially perpendicular to the axial direction. The first planet carrier and the second ring gear are configured to output a drive force from the transmission. The first planet carrier and the second ring gear can be mechanically connected to an output shaft. The first planet carrier and the second ring gear can be connected in a rotationally fixed manner to the output shaft. The first ring gear is connected in a rotationally fixed manner to the second sun gear. A sun ring gear can form the first ring gear on an inner circumference and the second sun gear on an outer circumference.

[0008] The first planetary carrier is rotatably mounted on the second planetary carrier via a transmission bearing designed to support a radial force. The transmission bearing can be formed by a radial bearing, such as a ball bearing, or a tapered roller bearing. This can provide accurate centering of the first planetary gear set and the second planetary gear set. Impairment of component life and excessive noise generation can be reduced.

[0009] The first planet carrier can be arranged at least partially within the second planet carrier in a radial direction. The first planet carrier can have an outer circumference, for example an outer diameter, that is smaller than an outer circumference, for example an outer diameter, of the second planet carrier. The first planet carrier can be arranged in the radial direction within the second planet carrier in a region in the axial direction in which the transmission bearing is arranged.

[0010] 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.

[0011] 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, such as 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.

[0012] 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 in a rotationally fixed manner to the output shaft. The second ring gear can be connected in a rotationally fixed manner to the first planet carrier. At least one of the second ring gear and the first planet carrier can be formed by the output shaft.

[0013] 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.

[0014] The second planet carrier can form a bearing seat for the transmission bearing on an inner circumference. The first planet carrier can form a bearing seat for the transmission bearing on an outer circumference. The second planet carrier can be designed in two parts. The second planet carrier can have a first section. The first section can be connected to the stationary component in a rotationally fixed manner or form the stationary component. The first section can have a shoulder. The shoulder can be designed to support the transmission bearing in the axial direction. The second section can form the bearing seat for the transmission bearing. The second section can be annular. The second section can form an annular section. The second section can be fastened to the first section. The first section can be arranged on a first side. The second section can be arranged on a second side.The second side may be a side of the transmission in the axial direction on which the output shaft is arranged. The first side may be arranged opposite the second side in the axial direction of the transmission.

[0015] In one embodiment of the transmission, the transmission bearing can be formed by a radial bearing. The transmission bearing can be formed by a roller bearing, for example a ball bearing, a deep groove ball bearing, a needle bearing, a plain bearing, or a tapered roller bearing.

[0016] In one embodiment of the transmission, the second planetary gear set can be arranged radially outward from the first planetary gear set. The second planetary gear set can be arranged axially in the same plane as the first planetary gear set. The first planetary gear set can form an inner planetary gear set, and the second planetary gear set can form an outer planetary gear set.

[0017] In one embodiment of the transmission, the transmission can have an output shaft for outputting a drive force from the transmission. The first planetary carrier and the second ring gear can be connected in a rotationally fixed manner to the output shaft for outputting a drive force. The output shaft can be arranged on the second side relative to the first gear set. The output shaft can form the second ring gear on an inner circumference. The output shaft can form the first planetary carrier.

[0018] In one embodiment of the transmission, the transmission bearing can be arranged on the first side, which, with respect to the first planetary gear set, is arranged in the axial direction opposite a side on which the output shaft is arranged. The output shaft can be arranged on the second side with respect to the transmission. The transmission bearing can be arranged in the axial direction opposite the output shaft with respect to the transmission.

[0019] In one embodiment of the transmission, the transmission can have a stationary component to which the second planet carrier is attached. The stationary component can be formed by a transmission housing. The stationary component can be formed by a transmission cover. The stationary component can be formed by the second planet carrier, or vice versa. The second planet carrier can be connected to the stationary component in a rotationally fixed manner. The second planet carrier can be connectable to the stationary component in a rotationally fixed manner, for example via a switching element such as a clutch or a freewheel. The second planet carrier can be screwed to the stationary component.

[0020] If the second planet carrier is designed in two parts, the second section of the second planet carrier can be fastened to the first section of the second planet carrier via screw connections. The second section can be positioned relative to the first section via a positioning element. The second section can be positioned relative to the first section in the radial direction via the positioning element. The positioning element can be formed by a dowel pin. The transmission can have two positioning elements. The two positioning elements can be arranged opposite one another in the radial direction with respect to the axis of rotation.

[0021] The second planetary carrier or the second section of the two-part second planetary carrier may have a receptacle for the second planetary pin. At least one of the stationary component, the second planetary carrier, and the first section of the second planetary carrier may have a thrust surface for the sun gear. The thrust surface may be configured to support an axial force of the sun gear. The thrust surface may extend circumferentially in the radial direction. The thrust surface may be arranged on the first side relative to the sun gear.

[0022] In one aspect, a drive unit for a vehicle is usable. The drive unit comprises an input shaft, a transmission according to one of the preceding

[0023] Embodiments and an output element. The input shaft is mechanically operatively connected to the first sun gear for inputting a drive force into the transmission. The output element is mechanically operatively connected to the output shaft for outputting a drive force from the transmission. The output element can be formed by a sprocket, a belt pulley, or a gearing, for example, a spur gearing. The output element can be arranged on the second side relative to the transmission.

[0024] The drive unit may include the first electric motor. The input shaft may be connected to the first rotor shaft in a rotationally fixed manner. The input shaft may be formed by the first rotor shaft. The input shaft may be connected between the first rotor and the first sun gear. The input shaft may be arranged on the first side relative to the first planetary gear set. The input shaft may be arranged on the same side as the transmission bearing relative to the first gear set. The input shaft and the transmission bearing may be arranged opposite the output shaft in the axial direction relative to the first gear set. The first sun gear may be connected to the first rotor via the input shaft in a rotationally fixed manner. The first electric motor may be configured to input an electric drive force into the transmission.

[0025] In one embodiment of the drive unit, the output shaft can be mechanically connected to the output element via an output gear. The output gear can be arranged on the second side relative to the output shaft. The output gear can be arranged offset in the axial direction from the first planetary gear set and the second planetary gear set. The output gear can be arranged radially within the second planetary gear set. The output gear can have an outer circumference, for example an outer diameter, that is smaller than an outer circumference, for example an outer diameter, of the second planetary gear set. The output element can be arranged on the second side relative to the output gear.

[0026] The output transmission can have a third planetary gear set. The output transmission can be formed by a third planetary gear set. The third planetary gear set can have at least one third sun gear, one third planet carrier, and one third ring gear. The third planetary transmission can further have one or more third planetary pins and one or more third planetary gears. The third sun gear can mesh with the third planetary gear. The third planetary gear can be rotatably mounted on the third planetary pin via a bearing, for example a radial bearing, a deep groove ball bearing, a plain bearing, or a needle bearing. The third planetary pin can be attached to the third planet carrier, for example, pressed into the third planet carrier. The third planetary gear can mesh with the third ring gear. The output shaft can be connected to the third sun gear in a rotationally fixed manner.The output shaft may form the third sun gear on an outer circumference. The third ring gear may be connected to the output element in a rotationally fixed manner.

[0027] The drive unit can have a second electric motor. The second electric motor can have a second rotor and a second stator. The second electric motor can be arranged axially parallel to the first electric motor. The second electric motor can be mechanically operatively connected to the output element via a transmission gear, for example via the third ring gear, for outputting a drive force. The third ring gear can have a toothing, for example a spur gear, for the mechanical operative connection with the transmission gear. The toothing can be arranged offset in the axial direction relative to the ring gear toothing of the third ring gear towards the second side.

[0028] At least one of the first planetary gear set, the second planetary gear set, and the third planetary gear set may be formed by a negative planetary gear set. At least one of the first planetary gear set, the second planetary gear set, and the third planetary gear set may be formed by a positive planetary gear set.

[0029] In one embodiment of the drive unit, the drive unit may have an input element that extends in the axial direction through at least one of the first electric motor, the transmission, and the output gear, and is arranged in the radial direction within the first sun gear. The input element may be formed by a pedal crankshaft. The input element may have pedals for receiving a mechanical drive force. The input element may be mechanically connected to the output gear. The input element may be rotationally fixedly connected to the third planet carrier. The input element, the first rotor, the first planetary gear set, the second planetary gear set, the output gear, and the output element may be arranged coaxially with one another.

[0030] In one aspect, a vehicle comprises at least one drive wheel and a drive unit according to one of the preceding embodiments. The vehicle can be operated at least temporarily using muscle power. The vehicle can be provided by a bicycle, an e-bike, or a pedelec. The drive wheel is mechanically operatively connected to the drive unit such that the drive unit can propel the vehicle. The vehicle can comprise other devices such as a braking device or a steering device. Fig. 1 shows a sectional view of an embodiment of a drive unit with a gearbox. Fig. 2 shows another embodiment of a drive unit with the transmission. Fig. 3 shows a plan view of a component of an embodiment of the transmission. Fig. 4 shows a sectional view of a component of an embodiment of the transmission.

[0031] Fig. Figure 1 shows a sectional view of an embodiment of a drive unit with a transmission. The drive unit comprises an input element 4, in this case a pedal crankshaft, the transmission, an output element 5, an output gear 30, and a first electric motor 70. The drive unit can be used for a human-powered vehicle, in this case an e-bike.

[0032] The transmission comprises a stationary component 9, a first planetary gear set 10, and a second planetary gear set 20. The first planetary gear set 10 comprises 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 comprises 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.

[0033] The first sun gear 11 is designed to input a drive force into the transmission. The first planet carrier 12 and the second ring gear 25 are designed to output a drive force from the transmission. The first ring gear 15 is rotationally fixedly connected to the second sun gear 21. The first planet carrier 12 is arranged radially within the second planet carrier 22, in an area in the axial direction in which the transmission bearing 45 is arranged. The first planet carrier 12 is rotatably mounted on the second planet carrier 22 via a transmission bearing 45, which is designed to absorb radial forces and is in this case a deep groove ball bearing. This ensures the clean centering of the first planetary gear set 10 relative to the second planetary gear set 20.

[0034] Further details of the drive unit and transmission are described below.

[0035] The input element 4 extends through the first sun gear 11 and the first electric motor 70. The first electric motor 70 has a first rotor 71 and a first stator 72, which are arranged in Fig. 2. The first stator 72 is fixed to the stationary component 9. The first rotor 71 is connected to the first sun gear 11 via an input shaft 73 in a rotationally fixed manner and is coaxial with 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 in the axial direction.

[0036] 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.

[0037] The second sun gear 21 meshes with the second planet gears 24. Each of the second planet gears 24 is mounted on one of the second planetary pinions 23 via a bearing, in this case a needle bearing. The second planetary pinions 23 are fastened to the second planet carrier 22. The second planet 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. The second output shaft 7 forms the first planetary carrier 12. As a result, the second ring gear 25 is connected in a rotationally fixed manner to the first planetary carrier 12.

[0038] The second planet carrier 22 is formed by the stationary component 9. The sun gear can engage the second planet carrier 22 in the axial direction on a first side and is thereby restricted in its movement in the axial direction. The first side is the left side in Fig. 1, on which the first electric motor 70 is arranged. The transmission bearing 45 is arranged on the first side. The output shaft 7 is arranged on a second side, which is opposite the first side with respect to the transmission.

[0039] Fig. 2 shows another embodiment of a drive unit with the transmission. Fig. 2 has all the features of the previous embodiment. In this case, the drive unit comprises a second electric motor 80. The second electric motor 80 has a second rotor 81 and a second stator 82. The output shaft 7 is rotationally fixedly connected to a third sun gear 31 of the output gear 30.

[0040] The output gear 30 is formed by a third planetary gear set and has 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 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 planet pinions 33 via a bearing, in this case a needle bearing. The third planet pinions 33 are fastened to the third planet carrier 32. The third planet gears 34 mesh with the third ring gear 35. The third ring gear 35 is connected to the output element 5 in a rotationally fixed manner.

[0041] 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 for outputting a drive force.

[0042] Fig. Figure 3 shows a top view of a component of one embodiment of the transmission. The present embodiment has all the features of one of the previous embodiments. In this case, the second planet carrier 22 is formed from an annular component. The second planet carrier 22 is attached to the stationary component 9 via screw connections. The second planet carrier 22 is positioned on the stationary component 9 in the radial direction via dowel pins.

[0043] Fig.4 shows a sectional view of a component of an embodiment of the transmission. The present embodiment has all the features of the previous embodiment. The second planet carrier 22 has a bearing seat for the transmission bearing 45 on an inner circumference. The second planet carrier 22 is arranged on the second side relative to a receiving portion for the second planet carrier 22 of the stationary component 9. The stationary component 9 forms a shoulder against which the transmission bearing 45 bears in the axial direction. This limits the movement of the transmission bearing 45 in the axial direction towards the first side. The transmission bearing 45 is pressed into the bearing seat of the second planet carrier 22. Reference symbol 4 Input element 5 Output element 7 Output shaft 9 Stationary component 10 First planetary gear set 11 First sun gear 12 First planet 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 gears 31 Third sun gear 32 Third planet carrier 33 Third planetary bolt 34 Third planetary gear 35 Third ring gear 36 gearing 45 gearbox bearings 70 First electric motor 71 First rotor 72 First stator 73 Input shaft 80 Second electric motor 81 Second rotor 82 Second stator

Claims

[1] Transmission with a first planetary gear set (10) having at least a first sun gear (11), a first planet carrier (12) and a first ring gear (15), and a second planetary gear set (20) having at least a second sun gear (21), a second planet carrier (22) and a second ring gear (25), wherein the first sun gear (11) is designed to input a driving force into the transmission, the first planet carrier (12) and the second ring gear (25) are designed to output a drive force from the transmission, the first ring gear (15) is connected in a rotationally fixed manner to the second sun gear (21), and the first planet carrier (12) is rotatably mounted on the second planet carrier (22) via a gear bearing (45) designed to support a radial force, wherein the gear bearing (45) is formed by a radial bearing. [2] Transmission according to one of the preceding claims, characterized bythat the second planetary gear set (20) is arranged in a radial direction outside the first planetary gear set (10). [3] Transmission according to one of the preceding claims, characterized by that the transmission has an output shaft (7) for outputting a drive force from the transmission, and the first planet carrier (12) and the second ring gear (25) are connected in a rotationally fixed manner to the output shaft (7) for outputting a drive force. [4] Transmission according to claim 3, characterized by that the transmission bearing (45) is arranged on a first side which, with respect to the first planetary gear set (10), is arranged in the axial direction opposite to a side on which the output shaft (7) is arranged. [5] Transmission according to one of the preceding claims, characterized by that the transmission has a stationary component (9) to which the second planet carrier (22) is fastened. [6] Drive unit for a vehicle, the drive unit comprising an input shaft (73), a transmission according to one of the preceding claims and an output element (5), wherein the input shaft (73) is mechanically connected to the first sun gear (11) for inputting a drive force into the transmission, and the output element (5) is mechanically connected to the output shaft (7) for outputting a drive force from the transmission. [7] Drive unit according to claim 6, characterized by that the output shaft (7) is mechanically connected to the output element (5) via an output gear (30). [8] Drive unit according to one of claims 6 to 7, characterized by that the drive unit has an input element (4) which extends in the axial direction through at least one of the transmission and the output gear (30) and is arranged in the radial direction within the first sun gear (11). [9] Vehicle with at least one drive wheel and a drive unit according to claims 6 to 8, wherein the drive wheel is mechanically operatively connected to the drive unit such that the drive unit can move the vehicle.

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