Bicycle

Abstract

To provide a bicycle capable of preventing a fall due to, for example, slipping.SOLUTION: A bicycle (1) includes, for example: a handle (10); a shaft (20) fastened to the handle (10); a cover (30); a bearing (50) that supports the shaft (20) so as to be rotatable relative to the cover (30); and a wheel (40) supported by the shaft (20). Placed at the cover (30) are a torque sensor (100), and a motor (60) that turns the handle (10).SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a bicycle.

Background Art

[0002] Generally, a bicycle rider travels while controlling the traveling direction and adjusting the balance by operating the handle and the like. There is known a bicycle provided with a control device capable of controlling the operation of the handle as needed during driving. For example, Patent Document 1 discloses a bicycle including a load device that applies a rotational force to a shaft connecting a front wheel and a handle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] During rainy days or the like, the wheels of a bicycle may slip while traveling. An example of the problem of the present invention is to provide a bicycle that can prevent falling due to slipping.

Means for Solving the Problems

[0005] A bicycle according to an example of the present invention includes a handle, a shaft fixed to the handle, a cover, a bearing that rotatably supports the shaft with respect to the cover, and a wheel supported by the shaft. A torque sensor and a motor for rotating the handle are disposed on the cover.

Brief Description of the Drawings

[0006]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0007] In the description of the embodiment of the present invention, for convenience of explanation, the direction along the axis X (central axis of a part 24 of the shaft 20) is referred to as the axial direction. In the axial direction, the direction away from the handle 10 (arrow a direction) is the lower side or one side, and the direction approaching the handle 10 (arrow b direction) is the upper side or the other side. However, the "lower side" and "upper side" do not necessarily coincide with the up and down directions in the vertical direction. Also, the arrow cd direction (FIGS. 4 and 5) orthogonal to the axis X is referred to as the radial direction, the arrow c direction away from the axis X is the outer side or one side in the radial direction, and the arrow d direction approaching the axis X is the inner side or the other side in the radial direction. In a certain member or part, the surface on the outer side (arrow c direction) in the radial direction is referred to as the outer peripheral surface, and the surface on the inner side (arrow d direction) in the radial direction is referred to as the inner peripheral surface. Further, the direction of rotation around the axis X is referred to as the circumferential direction.

[0008] Hereinafter, an embodiment which is an example of the present invention will be described with reference to the drawings. FIG. 1 is a side view of a bicycle 1 according to the present embodiment. FIG. 2 is a diagram schematically showing the configuration inside the cover 30 in the bicycle 1.

[0009] As shown in FIG. 1, the bicycle 1 includes a frame F, a saddle S, pedals P, a transmission body C, handlebars 10, a shaft 20, a cover 30, and wheels 40. The wheels 40 include a first wheel (front wheel) 41 and a second wheel (rear wheel) 42. The shaft 20 is fixed to the handlebars 10, and the wheel 40 (front wheel 41) is supported by the shaft 20. That is, the handlebars 10 are connected to the front wheel 41 via the shaft 20. The shaft 20 has an end 22 on the side closer to the front wheel 41 divided into two, and supports the front wheel 41 so as to sandwich the rotation axis of the front wheel 41. The shaft 20 may be integrally formed from the connection portion 21 with the handlebars 10 to the support portion 23 of the front wheel 41, or may be formed by combining a plurality of members. The transmission body C may be a chain or a belt. Note that the bicycle 1 may be an electric assist bicycle including a battery and a drive unit.

[0010] When the driver sits on the saddle S of the bicycle 1 and rotates the pedals P with their feet, a driving force is transmitted to the wheels 40 (typically the rear wheel 42) via the transmission body C, enabling forward travel. At that time, the driver can adjust the angle of the front wheel 41 via the shaft 20 by operating the handlebars 10.

[0011] The cover 30 is a member that houses a part 24 (FIG. 2) of the shaft 20. The cover 30 may be box-shaped, cylindrical, or any other arbitrary shape. In FIGS. 1 and 2, the cover 30 is schematically illustrated as a rectangular parallelepiped box. The cover 30 is fixed to the front (the traveling direction side of the bicycle) of the frame F. The cover 30 may be integrally formed with the frame F.

[0012] In FIG. 2, for the sake of convenience, the members inside the cover 30 are shown by solid lines, and the cover 30 and the members outside the cover 30 are shown by phantom lines. Inside the cover 30, a part 24 of the shaft 20, a first bearing 50 that rotatably supports the shaft 20 with respect to the cover 30, a motor 60, a speed reducer 70, a rotating shaft 80 of the motor 60, and a second bearing 90 that rotatably supports the rotating shaft 80 with respect to the cover 30, and a torque sensor 100 are arranged.

[0013] The shaft 20 passes through the cover 30 through a hole 31 formed at an end 33 of the cover 30 on the side close to the handle 10 (the other side in the axial direction (the direction of arrow b)), and a hole 32 formed at an end 34 on the side close to the front wheel 41 (one side in the axial direction (the direction of arrow a)). Inside the cover 30, a torque sensor 100 is attached, and a first bearing 50 is attached inside the torque sensor 100 (the side close to the shaft 20). That is, the torque sensor 100 is supported by the first bearing 50 and the cover 30. FIG. 2 shows a mode in which the torque sensor 100 and the first bearing 50 are attached to an end 33 of the cover 30 on the other side in the axial direction (the direction of arrow b). However, the torque sensor 100 and the first bearing 50 may be attached to an end 34 of the cover 30 on one side in the axial direction (the direction of arrow a), or may be attached at any position between the end 33 and the end 34. Examples of the detailed configuration of the torque sensor 100 and the first bearing 50 will be described later.

[0014] The bicycle 1 may be provided with another bearing (not shown) that rotatably supports the shaft 20 with respect to the cover 30. The other bearing may be arranged near an end of the cover 30 on the side opposite to the side where the first bearing 50 is arranged, or may be arranged at other locations.

[0015] Inside the cover 30, a motor 60 having a rotating shaft 80 is fixed. The rotating shaft 80 is rotatably supported with respect to the cover 30 via a second bearing 90 fixed to the cover 30. The second bearing 90 may be a ball bearing, a sleeve bearing, or various other bearings. In FIG. 2, a mode is shown in which the rotating shaft 80 extends in the other axial direction (arrow b direction) from the motor 60 in parallel with a part 24 of the shaft 20. However, the rotating shaft 80 may extend in the one axial direction (arrow a direction) from the motor 60 in parallel with a part 24 of the shaft 20. Also, depending on the configuration of the speed reducer 70 described later, the rotating shaft 80 may not extend in parallel with a part 24 of the shaft 20.

[0016] The speed reducer 70 transmits the rotation of the rotating shaft 80 of the motor 60 to the shaft 20. The speed reducer 70 includes, for example, a first gear 71 fixed to the rotating shaft 80 of the motor 60 and a second gear 72 fixed to a part 24 of the shaft 20. The first gear 71 meshes with the second gear 72. However, the speed reducer 70 may include other gears. Also, the speed reducer 70 may have a mechanism including a belt and pulleys instead of or in addition to the gears. The motor 60 can rotate the shaft 20, and thus the handle 10, via the speed reducer 70.

[0017] As a modification, the bicycle of the present invention may be the bicycle 1a shown in FIG. 3. The bicycle 1a has the same configuration as the bicycle 1 except that it includes a shaft 20a instead of the shaft 20, includes a cover 30a instead of the cover 30, and the configuration of each member inside the cover 30a is different. In FIG. 3, for convenience, the members inside the cover 30a are shown by solid lines, and the cover 30a and the members outside the cover 30a are shown by virtual lines.

[0018] The shaft 20a is divided inside the cover 30a into a first portion 24a1 on one side in the axial direction (in the direction of arrow a) and a second portion 24a2 on the other side in the axial direction (in the direction of arrow b). FIG. 3 shows a mode in which the torque sensor 100 and the first bearing 50 are arranged on the second portion 24a2 of the shaft 20a. However, the torque sensor 100 and the first bearing 50 may be arranged on the first portion 24a1 of the shaft 20a.

[0019] Inside the cover 30a, a motor 60a having a rotating shaft 80a is fixed. The motor 60a includes, for example, a speed reducer (not shown) such as a planetary gear mechanism inside, and can reduce the rotation of a rotor (not shown) and transmit it to the rotating shaft 80a. One side in the axial direction (in the direction of arrow a) of the rotating shaft 80a of the motor 60a is connected to the first portion 24a1 of the shaft 20a, and the other side in the axial direction (in the direction of arrow b) is connected to the second portion 24a2 of the shaft 20a. Inside the cover 30a, the first portion 24a1, the second portion 24a2, and the rotating shaft 80a of the shaft 20a are arranged coaxially. The configuration of the shaft 20a outside the cover 30a is the same as that of the shaft 20 of the bicycle 1. The motor 60a can rotate the shaft 20a, and thus the handle 10, via the speed reducer.

[0020] In the bicycle 1a according to the above modification, since the shaft 20a and the motor 60a are arranged coaxially, it is possible to reduce the size of the cover 30a compared to the cover 30 of the bicycle 1.

[0021] Hereinafter, an example of the detailed configuration of the torque sensor 100 and the first bearing 50 will be described. FIG. 4 is a perspective view showing an example of the torque sensor 100. FIG. 5 is a cross-sectional view showing an example of a state in which the torque sensor 100 is attached together with the first bearing 50 inside the cover 30. In the following description, an example of a mode in which the torque sensor 100 is attached to the shaft 20 and the cover 30 of the bicycle 1 is illustrated. However, in the following description, the bicycle 1, the shaft 20, and the cover 30 may be replaced with a bicycle 1a, a shaft 20a, and a cover 30a, respectively.

[0022] The torque sensor 100 includes a holder (strain body 101) and a strain sensor 103. In the radial direction, the first bearing 50 is held inside the strain body 101 (FIG. 5). In the present embodiment, the first bearing 50 is a ball bearing having an inner ring 51, an outer ring 52, and rolling elements. Note that the first bearing 50 is not limited to a ball bearing, and may be various other bearings such as a sleeve bearing.

[0023] As shown in FIGS. 4 and 5, the strain body 101 includes an inner peripheral portion (holding portion 110) attached to the first bearing 50, an outer peripheral portion (a plurality of attachment portions 120) surrounding the holding portion 110 in the radial direction, and a connection portion 130. The holding portion 110 is a cylindrical portion extending in the axial direction and having a cylindrical inner peripheral surface 110a around the axis X. The holding portion 110 is a portion that supports the shaft 20 via the first bearing 50. In FIG. 4, the outer shape (the outer shape in the radial direction) of the holding portion 110 is substantially square when viewed from the axial direction. However, the outer shape of the holding portion 110 is not limited to this, and may be any shape such as a circular shape, a substantially circular shape, an elliptical shape, a substantially elliptical shape, a polygonal shape, or a shape including complex irregularities.

[0024] As shown in FIG. 5, in the axial direction, the dimension of the holding portion 110 is the same as or substantially the same as the dimension of the attachment portion 120. In the radial direction, one end surface (in the direction of arrow a) of the holding portion 110 in the axial direction is at a different position (on the side of the first bearing 50) from one end surface (in the direction of arrow a) of the attachment portion 120 in the axial direction.

[0025] From the end on the outer side in the radial direction (in the direction of arrow c) and on one side in the axial direction (in the direction of arrow a) of the holding part 110, four plate-like connecting parts 130 protrude radially outward (in the direction of arrow c). The four connecting parts 130 are arranged at positions that are rotationally symmetric (hereinafter also referred to as "four-fold symmetry" in this specification) such that they overlap when rotated 90° around the axis X. That is, the four connecting parts 130 are arranged at equal intervals (every 90°) in the circumferential direction. However, the arrangement and number of the connecting parts 130 may change according to the arrangement and number of the mounting parts 120. In the radial direction, at the outer side (in the direction of arrow c) of each connecting part 130, the end on one side in the axial direction (in the direction of arrow a) of the mounting part 120 is connected. Therefore, the connecting part 130 connects the holding part 110 and the mounting part 120 (particularly, the deformable surface 122 of the elastic part 121 described later). The connecting part 130 has elasticity and is deformable according to an external force.

[0026] The mounting part 120 is a part that can be used to attach the strain generating body 101 to the cover 30 and has a substantially L-shaped cross section. In the present embodiment, the strain generating body 101 includes four mounting parts 120. However, the number of the mounting parts 120 in the strain generating body 101 is not limited to four, and may be one, two, three, or five or more. In the present embodiment, the four mounting parts 120 are arranged at positions that are four-fold symmetric around the axis X. That is, the four mounting parts 120 are arranged at equal intervals (every 90°) in the circumferential direction. However, the plurality of mounting parts 120 may not be arranged at equal intervals in the circumferential direction. For example, with respect to a first mounting part 120, a second mounting part 120 may be arranged at an interval of n°, a third mounting part 120 may be arranged at an interval of (180 - n)° from there, and a fourth mounting part 120 may be arranged at an interval of n° from there. The mounting part 120 is deformable according to an external force. Since all four mounting parts 120 have the same configuration, hereinafter, only one mounting part 120 will be described in detail, and detailed descriptions of the other mounting parts 120 will be omitted.

[0027] The attachment portion 120 has a deformable surface 122 extending in the axial direction. The strain generating body 101 has a gap 140, which will be described later, between a part (elastic part 121) of the attachment portion 120 having the deformable surface 122 and a part of the holding portion 110 on the first bearing 50 side with respect to the elastic part 121. Due to the shape of the gap 140, the elastic part 121 of the attachment portion 120 has a thinner wall thickness (radial thickness) compared to other parts of the attachment portion 120, making it easier to deform with strain.

[0028] As shown in FIG. 5, in the radial direction, the attachment portion 120 faces the holding portion 110 with the gap 140 therebetween. In the axial direction, the gap 140 is formed on the other side (in the direction of arrow b) of the connecting portion 130. Due to the presence of the gap 140, the attachment portion 120 and the holding portion 110 are separated by a predetermined distance on the other side (in the direction of arrow b) in the axial direction from the connecting portion 130. The gap 140 penetrates the strain generating body 101 in the circumferential direction (the depth direction in FIG. 5).

[0029] The gap 140 includes two through-holes (hole portions) with different shapes. The gap 140 shown in FIG. 5 includes a first through-hole (hole portion) 141 having a circular or substantially circular cross-section and a second through-hole (slit) 142 connected to the first through-hole 141. In the axial direction, the second through-hole (slit) 142 is connected to the other side (in the direction of arrow b) of the first through-hole 141. Also, the second through-hole (slit) 142 has a narrower width (radial dimension) than the size (diameter) of the first through-hole 141. However, the shape of the gap 140 is not limited to this, and it can be any shape such as a shape having only the second through-hole (slit), a shape in which a plurality of through-holes having circular or substantially circular cross-sections are combined, or a shape having a second through-hole (slit) extending in the radial direction.

[0030] Since the first through hole 141 is formed, a concave portion 141a that is recessed outward in the radial direction (arrow c direction) is formed in the mounting portion 120 on the inner surface in the radial direction (arrow d direction) (the surface facing the holding portion 110). In the connecting portion 130, a concave portion 141b that is recessed toward one side in the axial direction (arrow a direction) is formed on the surface on the other side in the axial direction (arrow b direction). In the holding portion 110, a concave portion 141c that is recessed inward in the radial direction (arrow d direction) is formed on the outer surface in the radial direction (arrow c direction). Note that the concave portions 141a, 141b, and 141c are not defined by boundary portions and are connected as a smoothly continuous curved surface.

[0031] Each mounting portion 120 has an elastic portion 121, and each connecting portion 130 also has an elastic portion (in this embodiment, substantially the entire connecting portion 130 is an elastic portion). Therefore, the strain body 101 of the torque sensor 100 includes a plurality (eight in this embodiment) of elastic portions as a whole. The plurality of elastic portions are arranged side by side at positions that are rotationally symmetric (four-fold symmetry) in the circumferential direction (FIG. 4).

[0032] A strain sensor 103 is attached to the elastic portion 121 (deformable surface 122) of the mounting portion 120. By attaching a strain sensor 103 to each of the plurality of deformable surfaces 122, a plurality (four in this embodiment) of strain sensors 103 are attached to the torque sensor 100. However, the strain sensors 103 do not necessarily need to be attached to all of the plurality of deformable surfaces 122. The directions of the strains detected by the individual strain sensors 103 may be different from each other. The deformable surface 122 and the strain sensor 103 may each extend in the axial direction, the circumferential direction, or the radial direction.

[0033] The strain sensor 103 is attached so as to be able to detect the strain of the deformable surface 122. The strain sensor 103 is attached to the deformable surface 122 such that the grid orientation (typically, the longitudinal direction of the strain sensor 103) is in a predetermined direction (which may be any of the axial direction, the circumferential direction, or the radial direction, and is the axial direction in the illustrated example). The grid orientations of the plurality of strain sensors 103 are not limited to the axial direction, but may be the circumferential direction, the radial direction, or a direction oblique to the axial direction. Among the plurality of strain sensors, the grid orientations of two strain sensors 103 facing each other may be the axial direction, and the grid orientations of the other two strain sensors 103 facing each other may be the circumferential direction. Or, the grid orientations of two strain sensors 103 facing each other may be a direction combining the radial direction and the circumferential direction (an oblique direction (first direction)), and the orientations of the other two strain sensors 103 facing each other may be a direction combining the radial direction and the circumferential direction (an oblique direction (second direction) intersecting the first direction). When the strain sensor 103 is a strain gauge, the strain of the deformable surface 122 is detected as a change in resistance value. Note that the strain sensor 103 may be various other sensors such as a resistance element or a piezoelectric element.

[0034] As described above, in the present embodiment, the strain sensor 103 is attached to the outside in the radial direction of the deformable surface 122 (in the direction of arrow c). However, the strain sensor 103 may be attached to the surface 131 of the connection portion 130 (for example, the surface on one side in the axial direction (in the direction of arrow a)) as indicated by reference numeral 103a in FIG. 4. In this case, the surface 131 of the connection portion 130 is a deformable surface extending in the radial direction or the circumferential direction. Also, the strain sensor 103 may be attached to both the deformable surface 122 and the surface 131 of the connection portion 130. Further, some of the strain sensors 103 may be attached to the deformable surface 122, and some of the other strain sensors 103 may be attached to the surface 131 of the connection portion 130.

[0035] In the radial direction, outside the deformable surface 122 of the mounting portion 120 (in the direction of arrow c), a fixing portion 123 connected to the cover 30 is arranged. The fixing portion 123 is a rectangular plate-like portion extending radially outward (in the direction of arrow c) from the other end (in the direction of arrow b) in the axial direction of the deformable surface 122. For example, in the central portion of the fixing portion 123, a hole portion 123h having a circular or substantially circular cross-section and extending in the axial direction is formed. The mounting portion 120 is fixed to the cover 30 via a spacer 105 by a bolt 104 as a fastening member axially inserted into the hole portion 123h. Thereby, the strain generating body 101 is fixed to the cover 30.

[0036] In the radial direction, the first bearing 50 is arranged inside (in the direction of arrow d) the holding portion 110 of the strain generating body 101. The first bearing 50 is held by the holding portion 110 of the strain generating body 101. The inner ring 51 of the first bearing 50 is adhered or press-fitted to the outer peripheral surface of the portion 25 of the shaft 20 supported by the first bearing 50 with a bonding member such as resin. Thereby, the inner ring 51 of the first bearing 50 is fixed to the shaft 20. The outer ring 52 of the first bearing 50 is press-fitted to the inner peripheral surface 110a of the holding portion 110 of the strain generating body 101. The first bearing 50 rotatably supports the shaft 20 with respect to the strain generating body 101.

[0037] The shaft 20 is supported by the strain generating body 101 via the first bearing 50. In the axial direction, the other side (in the direction of arrow b) of the shaft 20 protrudes outside the cover 30 from the hole 31 of the cover 30. In the present embodiment, the shaft 20 is deformed by receiving an external force in the radial direction or the axial direction (or a radial or axial component of the external force), and the strain generating body 101 is deformed via the first bearing 50 as the shaft 20 deforms.

[0038] At the end of the holding portion 110 of the distortion generating body 101 on the other side (in the direction of arrow b) in the axial direction, an annular contact portion 111 protruding inward (in the direction of arrow d) in the radial direction is provided. The surface of the contact portion 111 on one side (in the direction of arrow a) in the axial direction is in contact with the end surface of the outer ring 52 of the first bearing 50 on the other side (in the direction of arrow b) in the axial direction. Thus, the contact portion 111 supports the first bearing 50 while restricting its movement in the other side (in the direction of arrow b) in the axial direction.

[0039] When a driver operating the bicycle 1 senses that the wheel 40 is about to slip, the driver applies force to the hand holding the handle 10 to prevent falling. At this time, since a force acts on the shaft 20 via the handle 10, the first bearing 50 tries to move, for example, in the radial direction, a part of the distortion generating body 101 is pressed outward (in the direction of arrow c) in the radial direction, and another part of the distortion generating body 101 is pulled inward (in the direction of arrow d) in the radial direction. Then, stress concentrates on the portion near the gap 140 of the distortion generating body 101 (for example, the elastic portion 121 of the mounting portion 120 or the connecting portion 130, etc.), and deformation accompanied by strain occurs in the portion near the gap 140. The deformation accompanied by strain is detected by the strain sensor 103.

[0040] The strain sensor 103 outputs the detected strain information as a signal. The output signal is input to a control device (not shown), and the control device controls the rotation of the motor 60 to adjust the angle of the shaft 20, and thus the angle of the front wheel 41 via the motor 60. In this way, by assisting the driver's operation of the handle 10, the bicycle 1 is prevented from falling.

[0041] When there are a plurality of strain sensors 103, the strain of the distortion generating body 101 corresponding to the inclination or deformation of the shaft 20 in all directions can be detected. In particular, in the torque sensor 100, since the four mounting portions 120 are located at positions that are rotationally symmetric four times around the axis X, the strain in all directions can be detected more accurately.

[0042] The torque sensor 100 has a simple configuration including a strain generating body 101 and a strain sensor 103, enabling miniaturization of the device. Also, since processing such as attaching a magnetic layer to the shaft 20 is unnecessary, manufacturing is easy.

[0043] In the torque sensor 100, in the radial direction, the mounting portion 120 faces the holding portion 110 with a gap 140 therebetween. As a result, in the torque sensor 100, the strain generating body 101 is easily deformed, and stress can be detected with high sensitivity.

[0044] As described above, the preferred embodiments of the bicycle of the present invention have been described. However, the bicycle of the present invention is not limited to the configurations of any of the above-described embodiments. For example, the bicycle of the present invention may be provided with a magnetostrictive torque sensor instead of or in addition to the torque sensor 100.

[0045] The torque sensor of the bicycle of the present invention may be attached to the outside of the cover. Also, a motor may be attached to the outside of the cover of the bicycle of the present invention.

[0046] In addition, those skilled in the art can appropriately modify the bicycle of the present invention in accordance with conventionally known knowledge, and can also change the shapes, dimensions, and combinations of various configurations. As long as the configuration of the present invention is still provided by such changes, of course, it is included in the scope of the present invention.

Explanation of Reference Numerals

[0047] 1... Bicycle, 10... Handlebar, 20... Shaft, 30... Cover, 40... Wheel, 50... Bearing (first bearing), 60... Motor, 100... Torque sensor, 101... Holder (strain generating body), 103... Strain sensor, 110... Inner peripheral portion (holding portion), 111... Contact portion, 120... Outer peripheral portion (mounting portion), 121... Elastic portion, 140... Gap, 141a, 141b, 141c... Recess, 130... Connection portion.

Claims

1. a handle; a shaft fixed to the handle; a cover; a bearing that rotatably supports the shaft with respect to the cover; a wheel supported by the shaft; and comprising; a bicycle, wherein a torque sensor and a motor for rotating the handle are arranged in the cover.

2. The bicycle according to claim 1, wherein the bearing is attached inside the torque sensor.

3. The torque sensor is attached inside the cover, and the torque sensor is supported by the bearing and the cover. The bicycle according to claim 2.

4. The torque sensor comprises a holder having an inner peripheral portion attached to the bearing, an outer peripheral portion, and a connecting portion connecting the inner peripheral portion and the outer peripheral portion, and a strain sensor, wherein the outer peripheral portion or the connecting portion has an elastic portion, and the strain sensor is attached to the elastic portion. The bicycle according to any one of claims 1 to 3.

5. The holder comprises a plurality of elastic portions including the elastic portion, and the plurality of elastic portions are arranged side by side in the circumferential direction. The bicycle according to claim 4.

6. In the radial direction, the outer peripheral portion and the inner peripheral portion face each other with a gap therebetween. The bicycle according to claim 4 or 5.

7. The outer peripheral portion has a recess that is recessed in the radial direction on the surface facing the inner peripheral portion. The bicycle according to claim 6.

8. The connecting portion has a recess that is recessed in the axial direction. The bicycle according to claim 6 or 7.

9. The holder has a contact portion that contacts the bearing in the axial direction. The bicycle according to any one of claims 4 to 8.

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