WO2010105607A2

WO2010105607A2 - Drive system for a motor-assisted bicycle

Info

Publication number: WO2010105607A2
Application number: PCT/DE2010/000296
Authority: WO
Inventors: Markus Neubauer
Original assignee: Schaeffler Technologies Gmbh & Co. Kg
Priority date: 2009-03-20
Filing date: 2010-03-17
Publication date: 2010-09-23
Also published as: DE102009014247A1; WO2010105607A3

Abstract

The invention relates to a drive system for a motor-assisted bicycle, comprising a shaft (1) driven by means of cranks (2), a motor unit having a stator and a rotor and disposed concentric to the shaft (1), and a planetary gearbox (15) driven by the motor unit and driving on the output side a chain ring (41) connected to the shaft (1), wherein the motor unit and the planetary gearbox (15) are received in a housing (16), further comprising a shell (4) connected to the housing (16), the shaft (1) being at least partially and rotatably received therein. The invention further relates to a drive system for a motor-assisted bicycle, comprising a shaft (1) driven by means of cranks (2), a motor unit having a stator (10) and a rotor (11) and disposed concentric to the shaft (10), and a planetary gearbox (15) driven by the motor unit and driving on the output side a chain ring (41), wherein chain ring (41) is supported on a planet carrier (39) of the planetary gearbox (15) such that it can be coupled. Both drive systems achieve the aim according to the invention of proposing a simple, user-friendly drive system.

Description

Name of the invention

Drive system for a motor-assisted bicycle

description

Field of the invention

The invention relates to a drive system according to claim 1 and to claim 4 for a motor-assisted bicycle, as well as a bicycle, in particular an e-bike, with a drive system according to claim 1 or 4.

From practice for drive systems for motor-assisted bicycles, the demand is known to allow for a series production as simple and fast production, in particular a fitting of the shaft in the frame. Next, the demand is known to allow the rotational movement of the user of the bicycle, especially at low speeds a comfortable ride, especially the driver at low speeds not to feel the detent of the motor unit with stator and rotor.

No. 6,296,072 B1 describes a drive system for a motor-assisted bicycle with a shaft that can be driven by means of cranks, wherein an engine unit is provided which comprises a rotor and a stator. Next, a two-stage planetary gear is provided. A chainring is provided, which is connected by means of a pawl lock with the crank. The rotor is mounted by rolling bearings directly on the shaft.

WO 99/30960 A2 describes a drive system for a motor-assisted bicycle, wherein an output of the motor unit directly drives a chainring.

DE 20 2004 010 269 111 describes a drive system for a motor-assisted bicycle, wherein the shaft is formed in three parts and comprises a central shaft which extends through the output shaft of the motor unit. A coupling of the shaft with the output shaft of the motor unit is formed by a planetary gear, which produces the connection in the manner of a centrifugally-operated friction clutch.

DE 196 19 967 C1 describes a drive system for a motor-assisted bicycle, wherein the motor is arranged coaxially to the shaft and a non-shiftable reduction gear, especially a planetary gear, is provided. The coupling between the transmission and the shaft comprises a ratchet unit which connects a planet carrier of the planetary gear with the shaft.

Object of the invention

It is the object of the invention to provide a simple, user-friendly drive system.

Summary of the invention

This object is achieved by the drive systems according to claim 1 or claim 4. The sleeve, within which the shaft is received in sections and rotatably, and which is connected to the housing, separates the shaft of the arranged in the rest of the housing motor unit spatially.

A sensor may be provided on the shaft inside the sleeve, which detects the rotational speed of the shaft and the torque transmitted to the shaft, wherein this sensor is also arranged electronically shielded by the motor unit with the stator and the rotor.

The outer surface of the sleeve is part of the housing, so that the assembly of the sleeve and thus the positionally correct arrangement of the shaft with the sensor simplifies with respect to the frame of the bicycle. The sleeve can in particular be designed as a preassembled structural unit, which can be produced independently of the remaining housing and, if necessary, fitted or exchanged in the housing.

It is preferably provided that the housing comprises a support disk, which is arranged axially centrally and is mounted on the sleeve. The support disc supports the transmission of mechanical loads, which the operator initiates via the crank and the shaft, to the frame of the bicycle, in particular when the support disc is arranged axially in the middle between the crank, ie essentially in the plane of symmetry of the bicycle.

It is preferably provided that the sleeve has a circumferential radial flange, on which the sleeve can be fastened to the housing. In the region of the flange, the sleeve is easily fixed to the housing, in particular, during assembly of the flange can be aligned in the correct position to the rest of the housing and thus the shaft with the associated sensors are placed in the correct position to the motor unit.

If the chainring is coupled to a planetary carrier of the planetary gear, a freewheel is formed, which counteracts an introduction of force the drive direction of the motor unit suppressed. Next, a grid of the motor unit forming stator and rotor is collected, so that the operator experiences even at low speeds and low engine speed a substantially undisturbed drive and thus a substantially steady driving feel.

It is preferably provided that the planet carrier is elastically supported on the shaft. The planet carrier is arranged in particular at a distance from the shaft and can be operated under elastic bias, the elastic bias allows a secure coupling to the chainring even in unfavorable driving conditions.

It is preferably provided that the coupling between the planet carrier and the chainring comprises a ramp toothing. Such a ramp toothing can be produced easily, in particular if the ramps of the toothing are embossed into the material.

It is preferably provided that a coupling flange is attached to the chainring, with which the planet carrier cooperates. The coupling flange covers sections of the shaft. The coupling flange is rotatably supported on the remaining housing. At the coupling flange, the ramp toothing can be arranged so that a structural change of the chainring is not required.

It is understood that a drive system according to claim 1 can be combined with a drive system according to claim.

Further advantages and features will become apparent from the dependent claims and from the description of embodiments of the invention.

The invention will be described and explained in more detail below with reference to the accompanying drawings. Brief description of the drawings

Fig. 1 shows a sectional view of a first embodiment of a drive system according to the invention for a bicycle, especially for an e-bike, and

Fig. 2 shows a sectional view of a second embodiment of a drive system according to the invention for a bicycle, especially for an e-bike.

Detailed description of the drawing

Fig. 1 shows a detail of a drive system for a not-shown bicycle, especially for an e-bike or a pedelec.

The drive system comprises a shaft 1, which is mounted by means of two cranks 2 rotatable about an axis 3 in a sleeve 4. The bearing of the shaft 1 in the sleeve 4 comprises two ball bearings 5, 6, which are axially spaced from each other and arranged substantially symmetrically to the plane of symmetry of the bicycle. The spherical roller of the two ball bearings 5, 6 rolls on a track on the outer surface of the body of the shaft 1 from. The ball bearings 5, 6 comprise an outer ring 7, 8, which is arranged in each case rotationally fixed on the inner circumferential surface 9 of the sleeve 4.

The drive system further comprises its concentric with the shaft 1 arranged motor unit with a stator 10 and a rotor 11. The rotor 11 is rotatably supported by means of two needle bearings 12, 13 on an outer circumferential surface 14 of the sleeve. The motor unit drives a two-stage planetary gear 15, wherein the motor unit and the planetary gear are accommodated in a housing 16, whose outer side is fixed to the frame, not shown, of the bicycle.

The shaft 1 radially next part of the housing 16 is formed by the sleeve 4. The shaft 1 radially farthest part of the housing 16 comprises an outer ring 17, on the inner circumferential surface 18 of the stator 10 of the motor unit is arranged rotationally fixed. The housing 16 further comprises a first axial end ring 19 which axially closes the housing 16 in the region of the motor unit. The first axial end ring 19 in rotatably connected to the sleeve 4 and em outer ring 17.

Axially outside of the first axial end ring 19, a receptacle 20 for a control system 21 for the motor unit is arranged. Further, the rotor 11 is supported by means of an axial needle bearing 22 on the first axial end ring 19.

The outer ring 17, the sleeve 4 and the first axial end ring 19 are firmly connected to each other, for example, welded or screwed. It is understood that these parts can be made in one piece with each other, for example, as an annular, centrally deepened deep-drawing or casting.

The housing 16 is further axially formed by a second axial end ring 23 which rests with a seal 24 on the outer ring 17.

The housing 16 forms a compact unit which can be mounted quickly together with the second axial end ring 23. The sleeve 4 with the sleeve 4 mounted in the shaft 1 is easy to position together with the housing 16 in the correct position. This is true even if the sleeve 4th separated from the ring 17 and the two axial end rings 23, 19 produced and retrofitted.

On the shaft 1, a sensor is provided which detects both the torque that initiates the operator via the crank 2 in the body of the shaft 1, as well as the rotational speed of the shaft 1. To detect the torque of the shaft 1, a magnetization is impressed on the body of the shaft 1, comprising two counter-rotating, radially spaced partial magnetizations whose magnetic field resulting outside the body of the shaft 1 disappears in the event that no torque is introduced into the shaft 1. If a torque is introduced into the shaft 1, results in a detectable outside the shaft 1 magnetic field, including a magnetic sensor, such as a coil assembly 25 is provided substantially axially in the middle of the sleeve 4. The sketched measuring principle is based on the magnetostrictive effect, which is described in more detail in WO 2008/138322 A1, especially page 7, line 7 to page 8, Z. 16. Reference is made to the said WO document to that extent.

On the body of the shaft 1, a teeth 26 is further provided with two axially spaced rows of teeth. The two rows of teeth provide a signal readable by means of a magnetic sensor, which enables the detection of the rotational speed of the shaft 1.

The detected by the sensor speed of the shaft 1 and the introduced into the shaft 1 torque are passed electronically to the control system 21. The control system 21 is arranged directly in the vicinity of the sensor, so that a transmission, for example by means of cables, is superfluous.

The control system 21 is mounted on a board 26 on an outwardly facing side of the first axial end ring 19. In the first axial end ring 19, a bore 27 is arranged through the measuring sensors in the area between the stator 10 and the rotor 11 are introduced in order to detect the function of the engine system can. The board 29 is disposed at a distance from the outwardly facing side of the first axial end ring 19 in the receptacle 20, wherein a copper plate, not shown, is provided between the board 29 and the outwardly facing side of the first axial end ring 19, which dissipates the heat supported.

The control controller 21 controls the motor unit in dependence on the values of the rotational speed and the torque of the shaft 1 detected by the sensor system; For example, control commands can be stored, due to which the motor unit emits an increased power at a low rotational speed of the shaft 1, but a high, introduced into the shaft 1 torque by the operator.

The housing 16 includes a support plate 28 which is formed axially substantially centrally and extends substantially radially. The support disk 28 is mounted on the rotor 11 and thus indirectly on the sleeve 4 by means of a roller bearing 29. If the operator unknowingly initiates a torque about a torque directed in the direction of travel, ie perpendicular to the paper plane in FIG. 1, ie a bending moment in the shaft 1, the bending moment is transmitted via the shaft 1, the ball bearings 5, 6, the sleeve 4 passed through the support plate 28 to the ring 17 and thus to the frame of the bicycle, so that the forces introduced into the drive device collected, especially when the support plate 28 is arranged in the plane of symmetry of the bicycle. It is understood that the two axial end rings 19, 23 may be provided for forwarding the forces.

The planetary gear 15 is formed as a two-part planetary gear and includes a first planetary stage 30 and a second planetary stage 31st The rotor 11 is connected on the output side to a sun 32 of the first planetary stage 30. The sun 32 meshes with at least three planets 33 of the first planetary stage 30, which are arranged by means of bolts 34 via needle bearings rotatably mounted on a planetary carrier 35 of the first planetary stages 30. The planets 33 of the first planetary stage 30 mesh with a ring gear 36 of the first planetary stage 30 which is secured to the inwardly facing side 18 of the ring 17 of the housing 16. The sun 32 thus drives the planetary carrier 35 of the first planetary stage 30.

With the planet carrier 35 of the first planetary stage 30 is a sun 37 of the second planetary stage 31, which in turn offset with at least three planets 38 of the second planetary stage 31 meshing a planet carrier 39 of the second planetary stage 31 in rotation, wherein the planetary carrier 39 of the second planetary stage 31 with a Ring gear 40 meshes, which is arranged on the inwardly facing side 18 of the ring 17 of the housing 16.

The two driven planet carriers 35, 39 of the two planetary stages 30, 31 are axially supported on the housing 16 via needle bearings (not shown in the drawing).

It is understood that for both planetary stages 30, 31, a common ring gear can be provided.

With the second planet carrier 39 of the second planetary stage 31, the shaft 1 and a chainring 41 is connected, wherein the chainring 41 is rotatably mounted on the shaft 1. The connection between the second planet carrier 39 of the second planetary stage 31 and the second axial end ring 23 is not rigid, but has a radial clearance, so that all of the at least three planets 38 of the second planetary stage 31 can transmit power. In the area of the shaft 1, the torque, which the operator inserts directly into the shaft 1 via the crank 2, is superimposed on the torque which is introduced into the shaft 1 by the motor unit via the planet carrier 39 of the second planetary stage 31. The resulting total torque is then transmitted to the chainring 41, which forwards the drive to the wheels.

In the following description of the second embodiment with reference to FIG. 2 in particular the differences from the embodiment shown in Fig. 1 are to be highlighted. In this case, the same reference numerals designate components which are identical or comparable in their technical function.

Fig. 2 shows a rotatably mounted in the sleeve 4 shaft 1 with a sensor described in more detail above for detecting the introduced into the shaft 1 torque and the rotational speed of the shaft 1. The sleeve 4 is

Component of the housing 16, which includes the outer ring 17 and the first axial end ring 19. The first axial end ring 19 is externally mounted so that the inwardly facing side of the first axial end ring 19 points to the control 21 which is disposed in the housing 20 closed by the first axial end ring 19.

On the sleeve 4, a circumferential radial flange 42 is integrally arranged with the body of the sleeve 4. The radial flange 42 is arranged in the receptacle 20 with respect to the first axial end ring 19 so that a first screw 43 connects the radial flange 42 with the first axial end ring 19 and thus the sleeve 4 with the housing 16.

The rotor 11 and the stator 10 are components of the motor unit, wherein the motor unit, a two-stage planetary gear 15 is connected downstream. The sun 32 of the first planetary stage 30 indirectly drives the planet carrier 35 of the first planetary stage 30, which in turn is non-rotatably connected to the sun 37 of the second planetary stage 31. The output of the second planetary stage 31 is formed by the planet carrier 39.

The planet carrier 39 of the second planetary stage has a distance from the shaft 1. At the planet carrier 39, the chainring 41 is mounted coupled. In the case of the coupling force is introduced from the planet carrier 39 in the chainring 41, so that a frictional connection between the planetary carrier 39 and the chainring 41 is formed. If no coupling between the planetary carrier 39 and the chainring 41 is provided, the chainring 41 can rotate substantially independently of the planet carrier 39. The chainring 41 is additionally rotatably connected to the shaft 1.

The pointing to the shaft 1 end portion 44 of the planet carrier 39 is elastically supported on the shaft 1. For this purpose, in the shaft 1, a circumferential locking ring 45 is introduced and an elastic spring means 46 between the locking ring 45 and the end portion 44 of the planet carrier 39 is arranged. The locking ring 45 is the abutment against which the end portion 44 of the planet carrier is supported.

The coupling between the planetary carrier 39 and the chainring 41 comprises a ramp toothing 47. In the region of the ramp toothing 47, a circumferential structure is provided in which ramps rising in a smooth manner alternate with steeply rising ramps. In the direction of the flat rising ramps, the ramp tooth 47 offers no resistance, while in the opposite direction, in the direction of the steeply rising ramps, a mechanical resistance occurs, so that a barrier is formed in the opposite direction. To form the ramp toothing 47, the planet carrier 39 has a deformation directed in the axial direction with a radially directed intermediate section 48. Next, a coupling flange 49 is rotatably attached to the chainring 41. The coupling flange 49 has a first, substantially radially extending portion on which the attachment to the chainring 41 is formed. The coupling flange has a second, substantially axially extending portion 50 and a third, again substantially radially extending portion 51.

The ramp toothing 47 is formed between the radially extending portion 51 of the coupling flange 49 and the radial intermediate portion 48 of the planetary carrier 39 of the second planetary stage 31. The spring means 46 ensures that the planet carrier 39 rests on the chainring 41 under slight prestressing in the region of the ramp toothing 47, taking advantage of a small axial clearance of the planetary carrier 39.

In the case of the coupling of the chainring 41 with the planet carrier 39, a first torque is entered directly into the shaft 1 by the operator. A second torque is introduced by the plant carrier 39 via the ramp teeth 47 in the coupling flange 49 in the chainring 41, so that overlap in the region of the chainring 41, the two torques to the resulting total torque.

In the region of the axial portion 50 of the coupling flange 49 and thus the chainring 41 is rotatably arranged by means of a rolling bearing 52 to the second axial end ring 23 of the housing 16; this rolling bearing 52 is designed as a thin-ring bearing.

The coupling flange 49 surrounds the shaft 1 in sections and thus acts as an extension of the housing 16. Further, the end portion 44 forms of the planet carrier 39 from a narrow gap with the shaft 1, so that a sealing effect occurs and the interior of the housing is protected against the ingress of coarse dirt.

The second axial end ring 23 of the housing 16 is fastened by means of a further screw 53 directly to the only partially shown frame 54 of the bicycle.

The assembly of the drive system shown in Fig. 2 is designed to be simple, by after installing the sleeve 4 in the housing 16 and attaching the housing 16 to the frame 54 only the first radial portion 54 of the coupling flange 49 to the chainring 41 to attach is.

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LIST OF REFERENCE NUMBERS

1 wave

crank

3 axis

4 sleeve

5 ball bearings

6 ball bearings

7 outer ring of the ball bearing 5

8 outer ring of the ball bearing 6

9 inner circumferential surface of the sleeve 4th

10 stators

11 rotor

12 needle roller bearings

13 needle roller bearings

14 outer circumferential surface of the sleeve. 4

15 planetary gear

16 housing

17 ring

18 inner circumferential surface of the ring 17th

19 first axial end ring

20 recording

21 control scheme

22 axial needle bearing

23 second axial end ring

24 seal

25 coil arrangement

26 board

27 bore

28 support disk

29 rolling bearings 30 first planetary stage

31 second planetary stage

32 Sun of the first planetary stage 30

33 planet of the first planetary stage 30 34 bolts

35 planet carrier of the first planetary stage 30

36 ring gear of the first planetary stage 30th

37 Sun of the second planetary stage 31

38 Planet of the second planetary stage 31 39 Planet carrier of the second planetary stage 31

40 ring gear of the second stage step 31

41 chainring

42 radial flange

43 first screw 44 end portion of the planet carrier 39th

45 Circlip

46 spring means

47 ramp toothing

48 radial intermediate portion 49 coupling flange

50 axial section

51 second radial section

52 rolling bearings

53 further screw 54 first radial section

Claims

claims

A drive system for a motor-assisted bicycle, comprising a shaft (1) driven by cranks (2), a motor unit arranged concentrically to the shaft (1) with a stator and a rotor, and a planetary gear (15) driven by the motor unit, the output side drives a chainring (41) connected to the shaft (1), the motor unit and the planetary gear (15) being accommodated in a housing (16), characterized by a sleeve (4) connected to the housing (16). , within which the shaft (1) is at least partially and rotatably received.

2. Drive system according to claim 1, characterized in that the housing (16) comprises a support disc (28) which is arranged axially centrally and is mounted on the sleeve (4).

3. Drive system according to claim 1 or 2, characterized in that the sleeve (4) has a circumferential radial flange (43) on which the sleeve (4) on the housing (16) can be fastened.

4. Drive system for a motor-assisted bicycle, comprising a shaft (1) which can be driven by means of cranks (2), a motor unit arranged concentrically with the shaft, with a stator (10) and a rotor (11), and a planetary gear driven by the motor unit ( 15), the output side a chainring (41) drives, characterized in that the chainring (41) is coupled to a planet carrier (39) of the planetary gear (15) is mounted.

5. Drive system according to claim 4, characterized in that the planet carrier (39) is elastically supported on the shaft (1).

6. Drive system according to claim 4 or 5, characterized in that the coupling between the planetary carrier (39) and the chainring (41) comprises a ramp toothing (47).

7. Drive system according to one of claims 4 to 6, characterized in that a coupling flange (49) on the chainring (41) is fastened, with which the planet carrier (39) cooperates.

8. Bicycle, in particular e-bike, comprising a drive system according to one of claims 1 to 3.

9. bicycle, in particular e-bike, comprising a drive system according to one of claims 4 to 7.