ELECTRIC BICYCLE DRIVE UNIT FASTENING ASSEMBLY

Abstract

An electric bicycle drive unit mounting arrangement (50) by which a mid-motor electric drive unit (30) is floatingly attached to a drive receptacle (21) of a bicycle frame (20), wherein the drive receptacle (21) comprises two mutually parallel frame-fixed and vertical frame flanges (211, 212), wherein a drive unit housing (34) comprises two parallel and vertical housing flanges (41, 42), wherein one housing flange (41) is attached to one frame flange (211) and the other housing flange (42) is attached to the other frame flange (212), defining a flange pairing, respectively, and wherein both flange pairings comprise respectively at least one rubber mount (80) by means of which the frame flange (211, 212) is connected to the associated housing flange (41, 42) in a floating and rubber-elastic manner, so that the housing flanges (41, 42) do not bear directly against the corresponding frame flanges (211, 212) in each case, but are spaced apart from the corresponding frame flanges (211, 212) by a spacing gap (58) with a gap dimension X of at least 0.3 mm.

Claims

1. An electric bicycle drive unit mounting arrangement for an electric mid-motor drive unit comprising: a drive receptacle including two mutually parallel frame-fixed and vertical frame flanges, a drive unit housing including two mutually parallel and vertical housing flanges, wherein one housing flange is attached to one frame flange and the other housing flange is attached to the other frame flange, respectively defining flange pairings, and both flange pairings comprise respectively at least one rubber mount for connecting the frame flange to the associated housing flange in a floating and rubber-elastic manner, so that the housing flanges do not rest directly against the corresponding frame flanges respectively, but are spaced apart from the corresponding frame flanges by a spacing gap of at least 0.3 mm.

2. The electric bicycle drive unit mounting arrangement of claim 1, wherein the rubber mount comprises a substantially annular or cylindrical rubber sleeve.

3. The electric bicycle drive unit mounting arrangement of claim 2, wherein said rubber sleeve is disposed in a substantially cylindrical ring-shaped gap between a stiff outer sleeve and a stiff inner sleeve.

4. The electric bicycle drive unit mounting arrangement of claim 3, wherein the outer sleeve is seated in a through bore of the housing flange.

5. The electric bicycle drive unit mounting arrangement of claim 3, wherein the inner sleeve is rigidly attached directly to the frame flange in a force-locking and/or form-locking manner.

6. The electric bicycle drive unit mounting arrangement of claim 5, wherein the inner sleeve comprises an internal thread into which an external thread of a screw bolt is screwed, which is inserted from a distal direction into a bolt opening of the frame flange.

7. The electric bicycle drive unit mounting arrangement of claim 3, wherein the rubber sleeve comprises a spacing collar arranged axially between the outer sleeve and the corresponding frame flange.

8. The electric bicycle drive unit mounting arrangement of claim 3, wherein form-locking structures are provided at the inside of the outer sleeve and at the outside of the inner sleeve, which form-lockingly engage with complementary form-locking structures at the outside and the inside of the rubber sleeve.

9. The electric bicycle drive unit mounting arrangement of claim 3, wherein the outer sleeve comprises an anti-rotation structure at its proximal longitudinal end by which the outer sleeve is supported against rotation against the drive unit housing.

Description

[0016] Hereinafter, an embodiment of the invention will be explained in more detail with reference to the drawings. They show:

[0017] FIG. 1 a vertical section I-I of an electric bicycle drive unit mounting arrangement with a mid-motor drive unit mounted to a bicycle frame side drive receptacle,

[0018] FIG. 2 a horizontal section II-II of the electric bicycle drive unit mounting arrangement of FIG. 1,

[0019] FIG. 3 is an enlarged view of the left-hand mounting arrangement III including a 3-part sleeve combination of FIG. 2, and

[0020] FIG. 4 an outer sleeve and an inner sleeve of the sleeve combination of FIG. 3.

[0021] FIG. 1 shows a schematic vertical section of an electric bicycle 10 with a bicycle frame 20 and a mid-motor drive unit 30. In the present case, the drive unit 30 is designed to be purely assistive and supports the human drive power of a rider during riding.

[0022] In the present case, only a small part of a frame down tube and a drive receptacle 21 of the electric bicycle 10 are shown. The drive unit 30 comprises a closed drive unit housing 34 in which an electric drive motor 32 and a gearbox 31 are arranged. The gearbox 31 may have a fixed ratio, may be a gear shift gearbox or may be a continuously variable gearbox. Furthermore, a transverse output shaft 35 is beared in the drive unit housing 34, which in the present case also constitutes the bottom bracket bearing shaft. Generally, the output shaft and the bottom bracket bearing shaft can be provided separately from each other, e.g. arranged concentrically to each other. A left and a right pedal crank 36 are provided at the two longitudinal ends of the output shaft 35 and pedals 37 are provided at their ends respectively. An output element 38 configured as a gear wheel with more than 20 teeth is provided in a rotationally fixed manner at the output shaft 35, which drives a rear sprocket of a rear wheel of the bicycle 10 via a chain drive.

[0023] FIGS. 1-3 show two mounting arrangements 50 by which the drive unit 30 is floatingly attached to the drive receptacle 21 of the bicycle frame 20. The drive receptacle 21 comprises two frame flanges 211, 212 which are fixed to the frame and parallel to each other and which are respectively arranged in a vertical plane, so that a clamp-like receptacle which is open at the bottom and U-shaped in cross-section is defined. Parallel housing flanges 41, 42 of the drive housing 34, which are also arranged in a vertical plane, are attached to the two frame flanges 211, 212 and project vertically upwards from the closed drive housing 34. Generally, the housing flanges can alternatively be integrated into the actual drive housing 34.

[0024] The left frame flange 211 is rubber-elastically mounted to the left housing flange 41 by a rubber mount 80, and the right frame flange 212 is rubber-elastically mounted to the right housing flange 42 by an identical rubber mount 80. The two housing flanges 41,42 comprise respectively a cylindrical through bore 49 into which a sleeve combination 60 is inserted from the proximal direction. The sleeve combination 60 essentially comprises a rigid outer sleeve 90 defined by a metal sleeve body 92, a rigid inner sleeve 70 defined by a metal sleeve body 72, and a substantially cylindrical resilient rubber sleeve 82 defining the rubber mount 80. The rubber sleeve 82 fills a cylindrical ring-shaped gap 100 between the substantially cylindrical inner peripheral surface of the outer sleeve 90 and the substantially cylindrical outer peripheral surface of the inner sleeve 70. The rubber sleeve 82 is adhesively bonded or vulcanised to the outer sleeve 90 and the inner sleeve 70, respectively.

[0025] The outer sleeve outer body is configured substantially cylindrically at its outer circumferential surface 99, and is inserted with its outer circumferential surface 99 in a clamping manner into the cylindrical inner circumferential surface of the through bore 49.

[0026] FIG. 4 shows the sleeve combination 60 without the rubber sleeve 82. In FIG. 4 in particular, it is clearly visible that the outer sleeve 90 comprises on the outside at its proximal longitudinal end a stop ring flange 94 standing in a radial plane, which comprises an anti-rotation structure 98 by way of two chordal linear flattenings 98′, the chord lines of which are parallel to each other. The outer sleeve 90, and thus the complete sleeve combination 60, is rotationally locked in the pre-assembled state at the drive unit 30 and in the final assembled state, since the flattening 98′ establishes a rotational form-locking in cooperation with a corresponding flat counter-surface 34′ of the drive unit housing 34, as can be seen for example in FIG. 1.

[0027] At the inside of the outer sleeve body 92, three form-locking pockets 96 are provided at the two longitudinal ends of the sleeve body 92, respectively, which correspond rotationally with similar form-locking ribs 74 at the outside of the inner sleeve body 72. The total of six form-locking pockets 96 and a total of six form-locking ribs 74 engage in a form-locking manner with corresponding complementary form-locking ribs and pockets of the rubber sleeve 82, so that in this way a reliably rotationally fixed connection between the inner sleeve 70 and the outer sleeve 90 is ensured even at high torques during assembly.

[0028] The inner sleeve 70 comprises an internal thread 76 on the inside into which an external thread 56 of a screw bolt 52 is screwed from proximal. The screw bolt 52 comprises a cylindrical threaded shank 54 and a bolt head 56. The associated frame flange 211,212 comprises a stepped through hole 27 through which the screw bolt 52 is inserted during assembly and screwed with its threaded shank 54 comprising the external thread 56 into the internal sleeve thread 76. In this way, the inner sleeve 70 is frictionally attached to the frame flange 211, 212.

[0029] As can be seen in particular in FIG. 3, the rubber sleeve 82 comprises at its distal longitudinal end a spacing collar 88 projecting radially outwards in a radial plane, which in the assembled state and only in the region of the outer sleeve 90 fills an axial gap 58 between the distal end face 43 of the outer sleeve 90 and the proximal flange face 23 of the associated frame flange 211,212. The spacing collar 88 thereby ensures a spacing gap x of approx. 1.0 mm between the housing flange 41,42 and the associated corresponding frame flange 211,212 in the static situation. Since at least one mounting arrangement 50 is provided both on the left and on the right, the drive unit 30 is centred in this way between the two frame flanges 211,212 in a floating manner.

[0030] In the dynamic situation, i.e. in operation, this always ensures a minimum distance gap which is always so large that the housing flanges 41,42 do not touch the associated frame flanges 211,212. This prevents the transmission of structure-borne noise from the drive unit housing 34 to the bicycle frame 20, so that the noise emissions caused by the drive unit 30 are reduced overall compared to a mounting arrangement with rigid connection of the drive unit to the bicycle frame.