drive unit of an e-bike or pedelec as well as e-bike or pedelec

Abstract

Drive unit (12) of an e-bike or pedelec, comprising a first sub-unit (12a) having a first housing (13a) and a pedal crank shaft (14) rotatably mounted in the first housing (13a), wherein the pedal crank shaft (14) is operatively connected to an output shaft (33) of the drive unit (12) in order to apply a rider-side torque to the output shaft (33), comprising a second sub-unit (12b) having a second housing (13b) and an electric machine housed in the second housing (13b), wherein a motor shaft of the electric machine extends perpendicular to the pedal crank shaft (14) and is operatively connected to the output shaft (33) via at least one gear stage in order to apply a motor-side torque to the output shaft (33), and comprising at least one separate cooling sink (15),which extends along the first housing (13a) for cooling the first sub-unit (12a) and / or along the second housing (13b) for cooling the second sub-unit (12b), wherein the at least separate heat sink (15) is detachably connected to the first housing (13a) of the first sub-unit (12a) and / or to the second housing (13b) of the second sub-unit (12b).

Description

[0001] The invention relates to a drive unit of an e-bike or pedelec and to an e-bike or pedelec.

[0002] EP 2 731 858 B1 discloses a bicycle designed as an e-bike or pedelec with a drive system. The drive system of the e-bike or pedelec has a pedal crankshaft, to which pedal cranks and a chain wheel engage. Furthermore, the drive system has an electric motor that is operatively connected to the pedal crankshaft via at least one gear stage to provide drive assistance. A motor shaft of the electric motor extends perpendicular to the pedal crankshaft. The electric motor and the at least one gear stage can thus be installed in a space-saving manner in a down tube of a bicycle frame.

[0003] FR 3 098 488 A1 discloses another e-bike or pedelec, wherein a drive system of the e-bike or pedelec shown therein again comprises a pedal crankshaft, to which a chain wheel and pedal cranks engage, and an electric motor. The electric motor is arranged concentrically around the pedal crankshaft. The drive system comprises a heat sink to cool the electric motor.

[0004] DE 10 2013 112 804 A1 discloses another bicycle designed as an e-bike or pedelec with a drive system. The drive system has a pedal crankshaft to which pedal cranks engage. Furthermore, the drive system has an electric motor-gearbox unit, with the electric motor arranged concentrically to the pedal crankshaft.

[0005] CN 2 16 070 376 U describes an embedded drive system for an electrically assisted bicycle in which the battery and drive module are housed in an integrated system within the frame housing to simplify assembly and increase efficiency. The system comprises a base with two support elements, which are partially elastic and allow for easy maintenance through removable connections. The design provides improved heat dissipation and protection from external influences, while the modules are electrically connected via pluggable connectors to facilitate maintenance and extend service life.

[0006] DE 10 2018 124 950 A1 describes a bicycle drive unit that enables a compact design by enclosing the motor in a housing mounted on the bicycle frame. The motor supports the bicycle's propulsion and is positioned so that its rotational axis intersects that of the crankshaft housing, allowing for a reduction in size along the crankshaft axis.

[0007] DE 10 2010 026 650 A1 relates to a bicycle with an electric auxiliary drive motor whose stator is integrated into the bicycle frame.

[0008] DE 10 2017 200 387 A1 relates to a bicycle with an integrated electric drive device comprising a drive housing with heat sources and a cooling device with a heat sink arranged rotatably relative to the drive housing in order to dissipate the heat generated by the heat sources to the outside.

[0009] There is a need for a drive unit for an e-bike or pedelec that also allows for effective cooling of the drive unit's components.

[0010] In particular, there is a need for a drive unit of an e-bike or pedelec in which effective cooling of the electric motor of the drive unit is possible, namely when the electric motor is not coaxial with the pedal crankshaft, but perpendicular to the pedal crankshaft and, when installed on the bicycle, is at least partially located in a down tube of a bicycle frame.

[0011] The object of the invention is to provide a corresponding drive unit of an e-bike or pedelec as well as an e-bike or pedelec with such a drive unit.

[0012] This object is achieved by a drive unit of an e-bike or pedelec according to claim 1 and by an e-bike or pedelec according to claim 15.

[0013] The drive unit has at least one separate heat sink, which extends along the first housing for cooling the first subunit and / or along the second housing for cooling the second subunit. The at least one separate heat sink is detachably connected to the first housing of the first subunit and / or to the second housing of the second subunit. At least one heat-conducting body is arranged between the respective heat sink and the first housing of the first subunit and / or between the respective heat sink and the second housing of the second subunit.

[0014] In the drive unit according to the invention, the at least one separate heat sink extends along the first housing of the first sub-unit of the drive unit and / or along the second housing of the second sub-unit of the drive unit. Since the respective heat sink is designed as a separate component, it can be adapted to the individual requirements of different bicycle frames without the need for modifications to other components of the drive unit. Furthermore, the respective heat sink can be easily replaced with a new heat sink during operation. This allows for effective cooling of components of the drive unit, in particular the electric motor of the drive unit.

[0015] At least one heat-conducting body is arranged between the respective heat sink and the first housing of the first subunit and / or between the respective heat sink and the second housing of the second subunit. In particular, the at least one heat-conducting body is pressed between the respective heat sink and the first housing and / or the second housing. This ensures particularly effective heat transfer from the first housing and / or second housing to the respective heat sink, ultimately resulting in particularly effective cooling of the drive unit. Components of the drive unit can be effectively cooled.

[0016] According to an advantageous development of the invention, the drive unit has a single separate heat sink which extends along the first housing to cool the first sub-unit and which also extends along the second housing to cool the second sub-unit, wherein this single separate heat sink is detachably connected to the first housing of the first sub-unit and / or to the second housing of the second sub-unit. In this preferred development of the drive unit according to the invention, the separate heat sink extends both along the first housing of the first sub-unit of the drive unit and along the second housing of the second sub-unit of the drive unit. Components in the region of the first sub-unit and the second sub-unit can be effectively cooled, in particular the electric machine of the second sub-unit.

[0017] According to an alternative development, the drive unit has a single separate heat sink, which extends along the first housing for cooling the first subunit and is detachably connected to the first housing of the first subunit, or which extends along the second housing for cooling the second subunit and is detachably connected to the second housing of the second subunit. In this development, the subunit of the drive unit, along whose housing the separate heat sink does not extend, can be assigned a heat sink integrally formed on the respective housing, which can then be thermally coupled and / or connected to the separate heat sink.

[0018] According to a further alternative development, the drive unit has a first separate heat sink, which extends along the first housing for cooling the first subunit, and a second separate heat sink, which extends along the second housing for cooling the second subunit. The first separate heat sink is detachably connected to the first housing of the first subunit, and the second separate heat sink is detachably connected to the second housing of the second subunit. In this development, the two separate heat sinks can be thermally coupled and / or interconnected.

[0019] Preferably, the respective heat sink has cooling fins on its side facing away from the respective heat conducting body, wherein the respective heat sink has a contour on its side facing the respective heat conducting body that is adapted to a contour of the respective heat conducting body on its side facing the respective heat sink, and wherein the respective heat conducting body has a contour on its side facing the first housing and / or the second housing that is adapted to a contour of the first housing and / or the second housing. This is preferred in order to enable effective heat transfer from the first housing of the first subunit and / or from the second housing of the second subunit to the respective heat sink and from the respective heat sink to the environment. Components of the drive unit can be cooled effectively.

[0020] Preferably, the respective heat sink has at least one cylindrical segment-like recess on its side facing the respective heat-conducting body, into which the respective heat-conducting body engages with a respective cylindrical segment-like projection. This allows for particularly advantageous heat transfer from the respective heat-conducting body to the respective heat sink. Components of the drive unit can be cooled effectively.

[0021] Preferably, the heat-conducting body has at least one cylindrical segment-like recess on its side facing the first housing and / or the second housing, into which the first housing and / or the second housing, which are cylindrically contoured, engage in sections. This allows for particularly advantageous heat transfer from the first housing and / or the second housing of the two subunits to the heat-conducting body. Components of the drive unit can be effectively cooled.

[0022] Preferred developments of the invention will become apparent from the dependent claims and the following description. Exemplary embodiments of the invention are explained in more detail, without being limited thereto, with reference to the drawings. Herein: Fig. 1 a section of an e-bike or pedelec in the area of ​​a drive unit according to the invention in side view, Fig. 2 the drive unit according to the invention in side view, Fig. 3 a heat sink and heat conducting body of the drive unit according to the invention in a perspective view from above, Fig. 4 the heat conducting body of the drive unit according to the invention in a perspective view from above, Fig. 5 the heat sink of the drive unit according to the invention in a perspective view from above, Fig. 6 the heat sink of the drive unit according to the invention in a perspective view from below, Fig. 7 a cross section through Fig. 1 along section line VII-VII, Fig. 8 a cross section through Fig. 2 along section line VIII-VIII.

[0023] Fig. 1 shows a section of a bicycle 10 designed as an e-bike or pedelec in the area of ​​a frame 11 of the bicycle 10 and a drive unit 12 thereof. In Fig. 2 the drive unit 12 is shown in isolation.

[0024] The drive unit 12 has a first subunit 12a with a first housing 13a and a second subunit 12b with a second housing 13b. The first subunit 12a has a pedal crankshaft 14 rotatably mounted in the first housing 13a, to which pedal cranks (not shown) and a chain wheel engage. The second subunit 12b has an electric motor 30 arranged in the housing 13b of the first subunit, which serves to provide drive assistance for the e-bike or pedelec.

[0025] The pedal crankshaft 14 of the first sub-unit 12a runs in Fig. 1 and Fig. 2 perpendicular to the plane of the drawing. A motor shaft 31 of the electric machine 30 runs in Fig. 1 and Fig. 2 in the plane of the drawing, i.e. perpendicular to the pedal crankshaft 14. Longitudinal center axes of the pedal crankshaft 14 and motor shaft 31 of the electric machine 30, which run perpendicular to each other, can intersect, but can also be spaced apart.

[0026] The motor shaft 31 of the electric motor 30 is operatively connected to the pedal crankshaft 14 via at least one gear stage (not shown). Such a gear stage may be arranged exclusively in the housing 13b of the second subunit 12b or exclusively in the housing 13a of the first subunit 12a. It is also possible for one gear stage to be arranged in each of the housings 13a, 13b of both subunits 12a, 12b.

[0027] The two housings 13a, 13b of the two sub-units 12a, 12b of the drive unit 12 are preferably connected to each other by screwing. Fig. 2, screws 15 are shown which extend through sections of the two housings 13a, 13.

[0028] Fig. 2 shows a parting plane 29 between the two housings 13a, 13 of the two sub-units 12a, 12b.

[0029] When mounted in the bicycle frame 11, the crankshaft 14 is freely accessible, allowing it to rotate freely. Sections of the housing 13a and the housing 13b are arranged in the bicycle frame 11, preferably in a down tube thereof.

[0030] In the preferred embodiment shown, the drive unit 12 according to the invention has a single separate heat sink 15 which extends along the first housing 13a for cooling the first sub-unit 12a and along the second housing 13b for cooling the second sub-unit 12b, namely at sections of the housings 13a, 13b of the sub-units 12a, 12b which, when installed on the bicycle frame 11, are not covered by the bicycle frame 11 and are therefore accessible from the outside, so that the heat sink 15 can dissipate heat from the housings 13a, 13b of the two sub-units 12a, 12b into the environment.

[0031] The separate heat sink 15 is detachably connected to the first housing 13a of the first subunit 12a and / or to the second housing 13b of the second subunit 12b. Preferably, the single separate heat sink 15 is detachably connected to both housings 13a, 13b of both subunits 12a, 12b.

[0032] Because the heat sink 15 is designed as a separate assembly, it can be individually adapted to, for example, a bicycle frame 11 without the need for modifications to the other components of the drive unit. Furthermore, the heat sink 15 can easily be replaced with another heat sink.

[0033] A single heat-conducting body 16 is preferably arranged between the heat sink 15 and the first housing 13a of the first sub-unit 12a, as well as between the heat sink 15 and the second housing 13b of the second sub-unit 12b. The heat-conducting body 16 promotes heat transfer from the housings 13a, 13b of the two sub-units 12a, 12b to the heat sink 15.

[0034] The heat-conducting body 16 can be formed as a single part and inserted into the heat sink 15. It is also possible for the heat-conducting body 16 to be molded onto the heat sink 15 and thus bonded to it.

[0035] Preferably, the heat-conducting body 16 is pressed between the heat sink 15 and the housings 13a, 13b of the two subunits 12a, 12b. This pressing is effected when the heat sink 15 is connected to the housings 13a, 13b.

[0036] The heat sink 15 has cooling fins 17 on a side facing away from the heat conducting body 16. The cooling fins 17 enable a particularly advantageous transfer of heat from the heat sink 15 to the environment.

[0037] The heat sink 15 has a contour on its side facing the heat conducting body 16 that is adapted to a contour of the heat conducting body 16 on its side facing the heat sink 15. This serves to ensure optimal heat transfer from the heat conducting body 16 to the heat sink 15.

[0038] The heat conducting body 16 has, on its side facing the first housing 13a and the second housing 13b of the two sub-units 12a, 12b, a contour which is adapted to the contour of the first housing 12a and the second housing 12b in order to enable optimal heat transfer from the two housings 12a, 12b to the heat conducting body 16.

[0039] According to Fig. 5, the heat sink 15 has cylindrical segment-like recesses 18, 19 on its side facing the heat conducting body 16. The heat conducting body 16 engages these cylindrical segment-like recesses 18, 19 of the heat sink 15 with corresponding cylindrical segment-like projections 20, 21. This allows for particularly advantageous heat transfer from the heat conducting body 16 to the heat sink 15.

[0040] The heat-conducting body 16 has, on its side facing the first housing 12a and the second housing 12b, cylindrical segment-like recesses 22, 23, into which the cylindrically contoured housings 13a, 13b of the subunits 12a, 12b engage in sections. This also ensures optimal heat transfer from the respective housing 13a, 13b of the respective subunit 12a, 12b to the heat-conducting body 16.

[0041] The cross sections of the Fig. 7, Fig. From Figure 8, it can be seen that the heat sink 15 can be screwed to the housing 13b of the subunit 12b via first screws 24 and to the bicycle frame 11, namely the down tube, via second screws 25. By loosening these screws 24, 25, the heat sink 15 can be removed and replaced. Fig. 3 to 6 show recesses 26 in the heat sink 15 and recesses 27 in the heat conducting body 16 for the passage of the screws 24, 25.

[0042] Preferably, the heat sink 15, on its side facing the heat conducting body 16, and / or the heat conducting body 16 define receiving spaces 28 for electrical connectors and / or electrical cables. In the illustrated embodiment, these receiving spaces are defined exclusively by the heat conducting body 16. This makes it possible to route or accommodate electrical cables and electrical connectors in a space-saving manner.

[0043] The heat-conducting body 16 is preferably made of a thermoplastic elastomer. However, other materials with good thermal conductivity properties can also be used, which can be elastically deformed and thus pressed together when the heat sink 15 is connected to the housings 13a, 13b of the subunits 12a, 12b and / or the frame 11.

[0044] The two housings 13a, 13b of the two sub-units 12a, 12b as well as the heat sink 15 are preferably made of a metallic material, but can also be made of hard plastic.

[0045] Heat can be dissipated from the drive unit 12 according to the invention. The interchangeability of the heat sink 15 allows the drive unit 12 to be individually adapted to different frames without the need to adapt other components of the same. The heat sink 15 can be easily replaced.

[0046] As already stated, the heat-conducting body 16 is preferably made of a thermoplastic elastomer. Other thermoplastic materials can also be used to provide the heat-conducting body 16. A heat-conducting body made of a thermoplastic not only provides excellent heat transfer from the housings 13a, 13b of the two subunits 12a, 12b to the heat sink 15, but such a thermoplastic can also provide damping properties and sealing functions. In particular, the ingress of structure-borne noise into the heat sink and also into the bicycle frame can be reduced.

[0047] If the heat sink 15 is damaged, it can be easily replaced. If the heat sink 15 has overheated, for example, due to a high power demand from the drive unit, the heat sink 15 can be replaced with a cold heat sink. In this case, the electric motor 30 of the drive unit 12 can then provide high power to support the drive over a longer period of time.

[0048] By designing the heat sink 15 as a separate assembly, the manufacturability of the drive unit 12 can also be simplified.

[0049] Furthermore, the heat sink 15 and the housings 13a, 13b can be made of different materials. For example, the housings 13a, 13b of the subunits can be made of a magnesium alloy material, and the heat sink can be made of an aluminum alloy material.

[0050] Furthermore, since the heat sink 15 is designed as a separate assembly, the drive unit 12 can be adapted to different needs of different OEMs and different bicycle frames by appropriately designing a heat sink 15.

[0051] In the preferred embodiment shown, the drive unit 12 according to the invention has a single, separate heat sink 15, which extends along the two housings 13a for cooling the two subunits 12a, 12b and is detachably connected to both housings 13a, 13b. In the preferred embodiment shown, a single heat-conducting body 16 is arranged between this single heat sink 15 and the housings 13a, 13b.

[0052] Alternatively, it is also possible for the drive unit 12 to have a first separate heat sink 15, which extends along the first housing 13a of the first sub-unit 12a to cool the first sub-unit 12a, and a second separate heat sink 15, which extends along the second housing 13b of the second sub-unit 12b to cool the second sub-unit 12b, wherein the first separate heat sink 15 is detachably connected to the first housing 13a of the first sub-unit 12a and the second separate heat sink 15 is detachably connected to the second housing 13b of the second sub-unit 12a. In this alternative drive unit, the two separate heat sinks 15 can be thermally coupled and / or interconnected.In this alternative, a first heat-conducting body 16 is preferably arranged between the first separate heat sink 15 and the first housing 13a, and a second heat-conducting body 16 is arranged between the second separate heat sink 15 and the second housing 13a, which second heat-conducting body 16 is then designed analogously to the above-described heat-conducting body 16. In particular, the respective heat-conducting body 16 is pressed between the respective heat sink 15 and the respective housing 13a, 13b and has the contours described above on the side facing the respective heat sink 15 and on the side facing the respective housing 13a, 13b.

[0053] Furthermore, it is alternatively also possible for the drive unit 12 to have a single separate heat sink 15, which extends along the first housing 13a for cooling the first sub-unit 12a and is detachably connected to the first housing 13a of the first sub-unit 12a, or which extends along the second housing 13b for cooling the second sub-unit 12b and is detachably connected to the second housing 13b of the second sub-unit 12b. In this alternative, the sub-unit of the drive unit 12 along whose housing the separate heat sink 15 does not extend can be assigned a heat sink integrally formed on the respective housing, which heat sink can then be thermally coupled and / or connected to the separate heat sink 15.Preferably, in this alternative, a heat conducting body 16 is also arranged between the respective separate heat sink 15 and the respective housing 13a, 13b, which is then designed analogously to the heat conducting body 16 described above.

Claims

[1] Drive unit (12) of an e-bike or pedelec, with a first sub-unit (12a) having a first housing (13a) and a pedal crankshaft (14) rotatably mounted in the first housing (13a), with a second sub-unit (12b) having a second housing (13b) and an electric machine (30) accommodated in the second housing (13b), wherein a motor shaft (31) of the electric machine (30) runs perpendicular to the pedal crankshaft (14) and is operatively connected to the pedal crankshaft (14), with at least one separate heat sink (15) which extends along the first housing (13a) for cooling the first sub-unit (12a) and / or along the second housing (13b) for cooling the second sub-unit (12b), wherein the at least one separate heat sink (15) is detachably connected to the first housing (13a) of the first sub-unit (12a) and / or to the second housing (13b) of the second sub-unit (12b), characterized by the fact that at least one heat-conducting body (16) is arranged between the respective heat sink (15) and the first housing (13a) of the first sub-unit (12a) and / or between the respective heat sink (15) and the second housing (13b) of the second sub-unit (12b). [2] Drive unit (12) according to claim 1, characterized by a single separate heat sink (15) extending along the first housing (13a) for cooling the first sub-unit (12a) and along the second housing (13b) for cooling the second sub-unit (12b), wherein the separate heat sink (15) is detachably connected to the first housing (13a) of the first sub-unit (12a) and / or to the second housing (13b) of the second sub-unit (12b). [3] Drive unit (12) according to claim 1, characterized by a single separate heat sink (15) extending along the first housing (13a) for cooling the first sub-unit (12a) or along the second housing (13b) for cooling the second sub-unit (12b), wherein the separate heat sink (15) is detachably connected to the first housing (13a) of the first sub-unit (12a) or to the second housing (13b) of the second sub-unit (12b). [4] Drive unit (12) according to claim 1, characterized by a first separate heat sink (15) extending along the first housing (13a) for cooling the first sub-unit (12a), and a second separate heat sink (15) extending along the second housing (13b) for cooling the second sub-unit (12b), wherein the first separate heat sink (15) is detachably connected to the first housing (13a) of the first sub-unit (12a) and the second separate heat sink (15) is detachably connected to the second housing (13b) of the second sub-unit (12b). [5] Drive unit (12) according to one of claims 1 to 4, characterized by that the at least one heat conducting body (16) is injection-molded onto the respective heat sink (15). [6] Drive unit (12) according to one of claims 1 to 5, characterized by that the at least one heat-conducting body (16) is pressed between the respective heat sink (15) and the first housing (13a) and / or the second housing (13b). [7] Drive unit (12) according to one of claims 1 to 6, characterized by , that the respective heat sink (15) has cooling fins (17) on its side facing away from the respective heat conducting body (16), the respective heat sink (15) has a contour on its side facing the respective heat conducting body (16) which is adapted to a contour of the respective heat conducting body (16) on its side facing the respective heat sink (15), the respective heat-conducting body (16) has, on its side facing the first housing (13a) and / or the second housing (13b), a contour which is adapted to a contour of the first housing (12a) and / or the second housing (12b). [8] Drive unit (12) according to claim 7, characterized by that the respective heat sink (15) has, on its side facing the respective heat conducting body (16), at least one cylinder segment-like recess (18, 19) into which the respective heat conducting body (16) projects with a respective cylinder segment-like projection (20, 21). [9] Drive unit (12) according to claim 7 or 8, characterized bythat the respective heat-conducting body (16) has, on its side facing the first housing (13a) and / or the second housing (13b), at least one cylinder-segment-like recess (22, 23) into which the first housing (13a) and / or the second housing (13b), which are contoured in a cylinder-like manner, engage in sections. [10] Drive unit (12) according to one of claims 1 to 9, characterized by that the respective heat sink (15) and / or the respective heat conducting body (16) delimit receiving spaces (28) for electrical connectors and / or electrical cables. [11] Drive unit (12) according to one of claims 1 to 10, characterized by that the respective heat conducting body (16) consists of a thermoplastic elastomer. [12] Drive unit (12) according to one of claims 1 to 11, characterized bythat the first housing (13a) of the first sub-unit (12a), the second housing (13b) of the first sub-unit (12b) and the respective heat sink (15) consist of a metallic material or of hard plastic. [13] Drive unit (12) according to one of claims 1 to 12, characterized by , that the motor shaft (31) of the electric machine (30) is operatively connected to the pedal crankshaft (14) via at least one gear stage, the at least one gear stage is arranged exclusively in the first housing (13a) of the first sub-unit (12a), or the at least one gear stage is arranged exclusively in the second housing (13b) of the second sub-unit (12b), or at least one gear stage is arranged in the first housing (13a) of the first sub-unit (12a) and at least one gear stage is arranged in the second housing (13b) of the second sub-unit (12b). [14] E-bike or pedelec (10) with a drive unit (12) according to one of claims 1 to 13.

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