Bicycle steering assist motor unit and bicycle provided with same

Abstract

A bicycle steering assist motor unit 1 has: a steering assist motor 11 for assisting the steering of the handle of a bicycle; and a torque transmission mechanism 12 for transmitting output torque of the steering assist motor 11 to a steering column 3 pulled up in an axial direction by an anchor 32. The torque transmission mechanism 12 has a torque transmitted part 22 which is connected to an outer peripheral surface 3a of the steering column 3 and transmits the output torque of the steering assist motor 11 to the steering column 3. The torque transmitted part 22 has a contact part 22a that comes into contact with a contacted region 3b, which extends in the axial direction on the outer peripheral surface 3a of the steering column 3, so as to transmit the output torque of the steering assist motor 11 to the steering column 3 through the frictional force generated between the contact part 22a and the steering column 3 by applying pressure in the radial direction.

Description

Motor unit for assisting steering of bicycle and bicycle equipped with the same

[0001] The present invention relates to a motor unit for assisting steering of a bicycle and a bicycle equipped with the same.

[0002] Bicycle steering assist motors that assist steering of a bicycle handlebar are known. For example, Patent Document 1 discloses a robotic steering mechanism for an autonomous bicycle that includes a sensor, a steering control assembly configured to adjust the steering angle of the bicycle's front wheel, and a controller that acquires values ​​from the sensor. The controller adjusts the steering angle using the steering control assembly based on the values ​​from the sensor.

[0003] The document discloses that the steering control assembly includes a steering actuator, a steering column, and a gear assembly. The document also discloses that the steering gear of the gear assembly is attached to the steering column with a set screw. Figure 4 of the document discloses an ahead stem structure for connecting the steering wheel to the steering column.

[0004] US Patent Application Publication No. 2020 / 0102043

[0005] The ahead stem structure disclosed in Patent Document 1 includes a top cap, a lifting member, and a bicycle stem. The lifting member is located inside the top of the steering column, and by rotating the top cap, it expands to press against the inner surface of the steering column. This allows the lifting member to lift the steering column in the axial direction. The top cap is located at the upper end of the steering column and is connected to the lifting member by a threaded portion. The bicycle stem is connected to the outer circumferential surface of the steering column.

[0006] In the configuration disclosed in Patent Document 1, it is necessary to machine a threaded hole in the steering column through which a screw for attaching the steering gear of the gear assembly passes. After the threaded hole is machined in the steering column, when the top cap of the ahead stem structure is rotated and the steering column is pulled up by the pulling-up member, the position of the threaded hole changes in the axial direction of the steering column.

[0007] Therefore, with the configuration disclosed in Patent Document 1, it is difficult to assemble the steering gear, i.e., the torque transmission part of the torque transmission mechanism that transmits the output torque of the motor to the steering column, to the steering column using the set screw.

[0008] In response to this, there is a demand for a motor unit configuration that utilizes an ahead stem structure to enable the torque transmission portion of the torque transmission mechanism that transmits the output torque of the motor to the steering column to be easily assembled to the steering column.

[0009] The present invention aims to realize a motor unit configuration that utilizes an ahead stem structure to easily assemble the torque transmission portion of a torque transmission mechanism that transmits the output torque of a motor to a steering column to the steering column.

[0010] The present inventors have studied a configuration for transmitting the torque of a motor to a steering column without modifying the steering column.

[0011] As a result of extensive research, the inventors came up with a configuration in which, after the steering column is pulled up in the axial direction by a pulling-up member with an ahead stem structure, a torque transmission receiving portion of a torque transmission mechanism that transmits the output torque of a motor to the steering column is clamped to the steering column. This makes it possible to transmit the output torque of the motor to the steering column without providing a screw hole in the steering column as in the configuration disclosed in Patent Document 1.

[0012] Therefore, by utilizing the ahead stem structure, the torque transmission portion of the torque transmission mechanism that transmits the output torque of the motor to the steering column can be easily assembled to the steering column.

[0013] As a result of the above-mentioned investigation, the inventors have come up with the following configuration.

[0014] A bicycle steering assist motor unit according to one embodiment of the present invention includes a steering assist motor that assists steering of a bicycle handlebar, and a torque transmission mechanism that transmits the output torque of the steering assist motor to a steering column that is pulled up axially by a pulling-up member. The torque transmission mechanism has a torque-transmitted portion connected to the outer peripheral surface of the steering column and that transmits the output torque of the motor to the steering column. The torque-transmitted portion has a contact portion that applies pressure radially to a contacted area extending axially on the outer peripheral surface of the steering column, thereby transmitting the output torque of the motor to the steering column by frictional force generated between the contact portion and the steering column.

[0015] As a result, in an ahead stem structure including a steering column that is pulled up in the axial direction by a pulling-up member, the output torque of the motor can be transmitted to the steering column via the contact portion of the torque transmission part that contacts the contacted area that extends in the axial direction on the outer circumferential surface of the steering column. That is, the contact portion applies pressure in the radial direction to the contacted area located on the outer circumferential surface of the steering column, and transmits the output torque of the motor to the steering column by the friction force that is generated between the contact portion and the steering column.

[0016] As described above, by transmitting the output torque of the motor to the steering column by the contact portion of the torque-transmitted portion, there is no need to provide a screw hole in the steering column for fixing the torque-transmitted portion of the torque transmission mechanism that transmits the output torque of the motor, as in the prior art.

[0017] Therefore, the above-described configuration makes it possible to realize a motor unit configuration in which the torque transmission portion of the torque transmission mechanism that transmits the output torque of the motor to the steering column can be easily assembled to the steering column by utilizing the ahead stem structure.

[0018] Furthermore, by changing the configuration of the torque transmission portion, the size of the area in which the contact portion contacts the contacted area on the outer peripheral surface of the steering column can be adjusted in the axial direction of the steering column, thereby making it easy to change the design of the bicycle steering assist motor unit depending on the output torque of the steering assist motor.

[0019] From another perspective, it is preferable that the bicycle steering assist motor unit of the present invention includes the following configuration: The steering assist motor is disposed in a position where, when viewed in the vertical direction, at least a portion of the steering assist motor overlaps with a down tube that constitutes a part of the bicycle body frame.

[0020] This allows the steering assist motor to be arranged compactly in the left-right direction relative to the bicycle body frame.

[0021] According to another aspect, the bicycle steering assist motor unit of the present invention preferably includes the following configuration: the bicycle steering assist motor unit further includes a battery that supplies power to the steering assist motor, and the steering assist motor and the battery are housed within the down tube.

[0022] This improves the design of bicycles equipped with a bicycle steering assist motor unit. Furthermore, by locating the steering assist motor and battery inside the down tube, the center of gravity of the bicycle can be lowered.

[0023] From another perspective, the bicycle steering assist motor unit of the present invention preferably includes the following configuration: the torque transmission portion has a cylindrical steering column connection portion that can contact the outer peripheral surface of the steering column while applying pressure in the radial direction, and the contact portion is part of the inner peripheral surface of the steering column connection portion.

[0024] This makes it possible to easily connect the torque-transmitted portion of the torque transmission mechanism to the steering column so as to be able to transmit torque.

[0025] A bicycle according to one embodiment of the present invention includes a bicycle operation assist motor unit having the above-described configuration. In this bicycle, the torque transmission unit of the torque transmission mechanism, which transmits the motor's output torque to the steering column, can be easily attached to the steering column using the ahead stem structure.

[0026] The terminology used in this specification is used for the purpose of defining particular embodiments only, and is not intended to limit the invention.

[0027] As used herein, "and / or" includes all combinations of one or more of the associated listed members.

[0028] As used herein, the use of "including," "comprising," or "having" and variations thereof identify the presence of stated features, steps, operations, elements, components, and / or equivalents thereof, but may include one or more of the steps, operations, elements, components, and / or groups thereof.

[0029] As used herein, the terms "attached," "connected," "coupled," and / or their equivalents are used broadly to encompass both "direct and indirect" attachments, connections, and couplings. Furthermore, "connected" and "coupled" are not limited to physical or mechanical connections or couplings, but can also include direct or indirect electrical connections or couplings.

[0030] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0031] Terms defined in commonly used dictionaries should be construed to have a meaning consistent with the relevant art and meaning in the context of this disclosure, and should not be construed in an idealized or overly formal sense unless expressly defined herein.

[0032] It will be understood that in describing the present invention, several techniques and processes are disclosed, each of which has distinct advantages and can be used in conjunction with one or more, or in some cases all, of the other disclosed techniques.

[0033] Thus, for the sake of clarity, the description of the present invention refrains from unnecessarily repeating every possible combination of the individual steps, but the specification and claims should be read with the understanding that all such combinations are within the scope of the present invention.

[0034] In this specification, an embodiment of a motor unit for assisting steering of a bicycle according to the present invention will be described.

[0035] In the following description, numerous specific examples are set forth to provide a thorough understanding of the present invention. However, it will be apparent to one skilled in the art that the present invention may be practiced without these specific examples.

[0036] Accordingly, the following disclosure is to be considered as illustrative of the present invention and is not intended to limit the invention to the specific embodiments illustrated by the following drawings or description.

[0037] [Bicycle] In this specification, a bicycle is a vehicle that has a handlebar, a steering column that passes through a head tube, at least one front wheel, and at least one rear wheel, and is driven by a rider who rotates pedals. The bicycle may be a two-wheeled vehicle or a three-wheeled vehicle. The bicycle may be a vehicle that leans left and right, or a vehicle that does not lean left and right.

[0038] [Handlebar] In this specification, the handlebar refers to a bar handle that extends in the left-right direction. The handlebar connector of the bicycle stem is connected to the left-right center of the handlebar.

[0039] [Assist] In this specification, the term "assist" refers to an operation of auxiliary inputting a rotational driving force to the steering column connected to the steering wheel, by an actuator, to rotate the steering wheel about the axis of the steering column, based on the input of a force by the occupant to the steering wheel or the input of an external force transmitted to the steering column via the front wheels. The assist includes a case in which the rotational driving force is input to the steering column so as to increase the input of the force by the occupant to the steering wheel, and a case in which the rotational driving force is input to the steering column so as to reduce the input of the external force transmitted to the steering column. When the input of the force by the occupant to the steering wheel is increased, the rotational driving force is input in a direction that further rotates the steering column. On the other hand, when the input of the external force transmitted to the steering column is reduced, the rotational driving force is input in a direction that suppresses the rotation of the steering column.

[0040] [Steering column] In this specification, the term "steering column" refers to a bicycle component that is rotatably housed within the head tube and connected to the front fork that rotatably supports the front wheel. The steering column is connected to a steering column connector of a bicycle stem.

[0041] According to one embodiment of the present invention, by utilizing an ahead stem structure, it is possible to realize a motor unit configuration in which the torque transmission portion of the torque transmission mechanism that transmits the output torque of the motor to the steering column can be easily assembled to the steering column.

[0042] Fig. 1 is a left side view showing the schematic configuration of a bicycle steering assist motor unit according to a first embodiment. Fig. 2 is a left side view showing the schematic configuration of a bicycle steering assist motor unit according to a second embodiment. Fig. 3 is a left side view showing the schematic configuration of a bicycle having a bicycle steering assist motor unit. Fig. 4 is a diagram showing the schematic configuration of a stem mechanism and a steering assist device. Fig. 5 is a left side view showing an example of a bicycle stem according to a fourth embodiment. Fig. 6 is a top view of the bicycle stem and bicycle steering assist motor unit. Fig. 7 is a left side view showing the schematic configuration of a bicycle in which a steering assist motor and a battery are housed in a down tube.

[0043] Hereinafter, embodiments will be described with reference to the drawings. In each drawing, the same parts are designated by the same reference numerals, and the description of the same parts will not be repeated. Note that the dimensions of the components in each drawing do not faithfully represent the actual dimensions of the components and the dimensional ratios of the components.

[0044] Hereinafter, arrow F in the figures indicates the forward direction of the vehicle. Arrow RR in the figures indicates the rearward direction of the vehicle. Arrow U in the figures indicates the upward direction of the vehicle. Arrow D in the figures indicates the downward direction of the vehicle. Arrow L in the figures indicates the leftward direction of the vehicle. Arrow R in the figures indicates the rightward direction of the vehicle. Furthermore, in the following explanation, the up-down direction, left-right direction, and front-rear direction respectively refer to the up-down direction, left-right direction, and front-rear direction when viewed from the rider riding the bicycle.

[0045] (Embodiment 1) A bicycle steering assist motor unit 1 according to embodiment 1 of the present invention will be described with reference to Figure 1. Figure 1 is a left side view showing the schematic configuration of the bicycle steering assist motor unit 1 according to embodiment 1.

[0046] The bicycle steering assist motor unit 1 includes a steering assist motor 11 and a torque transmission mechanism 12 .

[0047] The steering assist motor 11 outputs torque that rotates the steering column 3. The steering assist motor 11 is connected to the torque transmission mechanism 12 so as to be able to transmit the output torque. In other words, the output shaft 11a of the steering assist motor 11 is connected to the torque transmission mechanism 12 so as to be able to input the output torque.

[0048] Although not specifically shown, the steering assist motor 11 is supported by the bicycle body frame. In the example shown in Figure 1, the steering assist motor 11 is located in front of the steering column 3, but it may also be located behind, to the left or right of the steering column 3, as long as it is close to the steering column 3.

[0049] The torque transmission mechanism 12 transmits the output torque of the steering assist motor 11 to the steering column 3. More specifically, the torque transmission mechanism 12 has a torque transmitting portion 21 and a torque transmitted portion 22.

[0050] The torque transmission portion 22 is fixed onto the outer peripheral surface 3a of the steering column 3. Methods for fixing the torque transmission portion 22 to the steering column 3 include, for example, a fixing method using a clamp, a fixing method in which multiple separate parts are arranged to sandwich the steering column 3 in the radial direction and connected by fastening members, and the like.

[0051] The torque transmission portion 22 has a contact portion 22a that contacts a contacted region 3b that extends circumferentially and axially on the outer peripheral surface 3a of the steering column 3 so as to apply pressure in the radial direction and transmit the output torque of the steering assist motor 11 to the steering column 3 by frictional force generated between the torque transmission portion 22 and the contacted region 3b. The contacted region 3b is the region on the outer peripheral surface 3a of the steering column 3 that is in contact with the contact portion 22a of the torque transmission portion 22.

[0052] When the torque transmission portion 22 is a cylindrical member, the contacted region 3b is a cylindrical region located on the outer peripheral surface 3a of the steering column 3, and the contact portion 22a is a region located on the inner surface of the torque transmission portion 22. When the torque transmission portion 22 is a fan-shaped member when viewed in the axial direction of the steering column 3, the contacted region 3b is a fan-shaped region located on the outer peripheral surface 3a of the steering column 3 when viewed in the axial direction of the steering column 3, and the contact portion 22a is a fan-shaped region located on the inner surface of the torque transmission portion 22 when viewed in the axial direction of the steering column 3.

[0053] As a result, when torque is input to the torque transmission portion 22 fixed on the outer peripheral surface of the steering column 3, the steering column 3 rotates around the axis P together with the torque transmission portion 22.

[0054] The torque transmission unit 21 is connected to the output shaft 11a of the steering assist motor 11 so as to be able to transmit torque, and is also connected to the torque transmission-receiving unit 22 so as to be able to transmit torque. As a result, the torque transmission unit 21 transmits the torque output from the output shaft 11a of the steering assist motor 11 to the torque transmission-receiving unit 22. Therefore, the torque transmission-receiving unit 22 transmits the output torque of the steering assist motor 11 transmitted by the torque transmission unit 21 to the steering column 3.

[0055] The torque transmitting unit 21 and the torque transmitted unit 22 constitute a part of a mechanism capable of transmitting torque, such as a gear, a link, a belt, a chain, etc. The torque transmitting unit 21 and the torque transmitted unit 22 may be configured to change (amplify or decrease) the torque output from the steering assist motor 11.

[0056] The torque transmission mechanism 12 is housed in a casing 13. The casing 13 is supported by the bicycle body frame (not shown). Therefore, the torque transmission mechanism 12 is rotatable relative to the casing 13. The output shaft 11a of the steering assist motor 11 may be located inside the casing 13 or outside the casing 13.

[0057] The steering column 3 passes through the head tube 61 of the bicycle and is pulled up relative to the bicycle body frame (head tube 61) by the top cap 31 and anchor 32.

[0058] Specifically, the anchor 32 is disposed inside the upper portion of the steering column 3. A threaded portion (not shown) of the top cap 31 is rotatably connected to the top of the anchor 32. The anchor 32 is configured so that its outer surface can move radially using a dedicated anchor installation tool (not shown). The anchor 32 is pre-fixed to the inner peripheral surface of the steering column 3 with its outer surface moving radially to press against the inner peripheral surface of the steering column 3. The top cap 31 is disposed between the axial end face of the head tube 61 and the bicycle stem 33 and a portion of the bicycle steering assist motor unit 1 (the casing 13 and the torque transmission portion 22), which are each connected to the steering column 3. In this embodiment, the torque transmission portion 22 of the bicycle steering assist motor unit 1 is located closer to the head tube 61 than the bicycle stem 33 in the axial direction of the steering column 3.

[0059] In the above-described configuration, by rotating the top cap 31 as described above, the steering column 3 can be pulled up in the axial direction relative to the bicycle body frame (head tube 61) by the anchor 32. The anchor 32 corresponds to a pulling-up member.

[0060] In this way, the stem structure of this embodiment is a so-called ahead stem structure.

[0061] The bicycle steering assist motor unit 1 according to this embodiment includes a steering assist motor 11 that assists in steering the handlebars of a bicycle, and a torque transmission mechanism 12 that transmits the output torque of the steering assist motor 11 to a steering column 3 that is pulled up in the axial direction by an anchor 32. The torque transmission mechanism 12 is connected to the outer peripheral surface 3a of the steering column 3 and has a torque-transmitted portion 22 that transmits the output torque of the steering assist motor 11 to the steering column 3. The torque-transmitted portion 22 has a contact portion 22a that applies pressure in the radial direction to a contacted region 3b that extends axially on the outer peripheral surface 3a of the steering column 3, thereby transmitting the output torque of the steering assist motor 11 to the steering column 3 by frictional force generated between the contact portion 22 and the steering column 3.

[0062] As a result, in an ahead stem structure including the steering column 3 that is pulled up in the axial direction by the anchor 32, the output torque of the steering assist motor 11 can be transmitted to the steering column 3 via the contact portion 22a of the torque transmission portion 22 that contacts the contacted area 3b extending in the axial direction on the outer circumferential surface 3a of the steering column 3. In other words, the contact portion 22a transmits the output torque of the steering assist motor 11 to the steering column 3 by applying pressure in the radial direction to the contacted area 3b located on the outer circumferential surface 3a of the steering column 3, thereby generating frictional force between the contact portion 22a and the steering column 3.

[0063] As described above, by transmitting the output torque of the steering assist motor 11 to the steering column 3 by the contact portion 22a of the torque transmission portion 22, it is not necessary to provide a screw hole in the steering column for fixing the torque transmission portion of the torque transmission mechanism that transmits the output torque of the motor, as in the prior art.

[0064] Therefore, with the above-described configuration, it is possible to realize a configuration of a bicycle steering assist motor unit 1 in which the torque transmission portion 22 of the torque transmission mechanism 12 that transmits the output torque of the steering assist motor 11 to the steering column 3 can be easily assembled to the steering column 3 by utilizing the ahead stem structure.

[0065] 2 is a left side view showing the schematic configuration of a bicycle steering assist motor unit 100 according to a second embodiment. The bicycle steering assist motor unit 100 according to this embodiment differs from the bicycle steering assist motor unit 1 of the first embodiment in that the torque transmission portion 121 of the torque transmission mechanism 112 is a gear having two-stage gear portions 121a, 121b, and the torque transmission portion 122 has a gear portion 122a. In the following, the same components as those in the first embodiment are denoted by the same reference numerals and their description will be omitted, and only the components that differ from the first embodiment will be described.

[0066] 2, the bicycle steering assist motor unit 100 includes a steering assist motor 11 and a torque transmission mechanism 112. The torque transmission mechanism 112 includes a torque transmitting portion 121 and a torque transmitted portion 122.

[0067] The torque transmission unit 121 is a gear having two gear stages 121a and 121b. Specifically, the torque transmission unit 121 has a first gear stage 121a and a second gear stage 121b having a smaller diameter than the first gear stage 121a. The first gear stage 121a overlaps with the second gear stage 121b so that their rotation axes coincide. The first gear stage 121a and the second gear stage 121b are integrally formed. The torque transmission unit 121 is housed in the casing 113.

[0068] The first gear portion 121a meshes with a gear portion (not shown) formed on the outer peripheral surface of the output shaft 11a of the steering assist motor 11. The second gear portion 121b meshes with a gear portion 122a of a torque transmission portion 122, which will be described later.

[0069] The torque transmission recipient 122 has a gear portion 122a on at least a portion of its outer circumferential surface. The gear portion 122a is, for example, fan-shaped or semicircular when viewed in the axial direction of the steering column 3. The gear portion 122a meshes with the second gear portion 121b of the torque transmission portion 121. Similar to the torque transmission recipient 12 of the first embodiment, the torque transmission recipient 122 is fixed to the outer circumferential surface 3a of the steering column 3 by, for example, a clamping method, or a fixing method in which multiple separate parts are arranged to sandwich the steering column 3 in the radial direction and connected by fastening members.

[0070] Similar to the torque transmission portion 12 of the first embodiment, the torque transmission portion 122 has a contact portion 122b that applies pressure radially to a contact area 3b that extends circumferentially and axially on the outer circumferential surface 3a of the steering column 3, and contacts the contact area 3b so as to transmit the output torque of the steering assist motor 11 to the steering column 3 by the frictional force generated between the contact area 3b and the steering column 3.

[0071] With the above configuration, the output torque of the steering assist motor 11 can be transmitted to the steering column 3 by the torque transmission mechanism 112 .

[0072] (Embodiment 3) Figure 3 is a left side view showing the schematic configuration of a bicycle X having a bicycle steering assist motor unit 200. The bicycle X according to this embodiment is, for example, a two-wheeled vehicle. The bicycle X has a front wheel 4, a rear wheel 5, a body frame 6, and a steering mechanism 7. The configurations of the front wheel 4, the rear wheel 5, and the body frame 6 are the same as those of conventional bicycles, and detailed explanations will be omitted. Components similar to those in embodiments 1 and 2 will be assigned the same reference numerals and explanations will be omitted.

[0073] 3, the steering mechanism 7 includes a fork 71, a steering column 3, a stem mechanism 130, a steering assist device 73, and a handlebar 2. The steering column 3 extends obliquely so that its upper end is located rearward of its lower end.

[0074] The fork 71 rotatably supports the front wheel 4 at its lower end. The steering column 3 is connected to the upper end of the fork 71. The steering column 3 passes through the head tube 61 of the body frame 6. A stem mechanism 130 is attached to the upper end of the steering column 3. The handlebars 2 are supported by the stem mechanism 130. The steering assist device 73 assists in steering the handlebars 2 based on the torque input to the handlebars 2 or the steering column 3.

[0075] 4 is a diagram showing a schematic configuration of the stem mechanism 130 and the steering assist device 73. The stem mechanism 130 has a top cap 31, an anchor 32, and a bicycle stem 133.

[0076] The bicycle stem 133 has a handle holder 134 , a torque sensor 30 , and a steering column holder 135 .

[0077] The handle holding portion 134 has a handle connecting portion (not shown) at one end thereof, to which the handle 2 is connected. The other end of the handle holding portion 134 is connected to the torque sensor 30.

[0078] The steering column holding portion 135 has a steering column connecting portion 135a at one end thereof. The steering column 3 is connected to the steering column connecting portion 135a. The other end of the steering column holding portion 135 is connected to the torque sensor 30.

[0079] The torque sensor 30 is located behind the steering column 3. Therefore, the steering column holding portion 135 is connected to the steering column 3 so as to extend rearward. The handle holding portion 134 is located axially outward of the steering column 3 and extends in a direction intersecting the axis P of the steering column 3 when viewed in the left-right direction.

[0080] The torque sensor 30 is positioned so as to overlap at least a portion of the anchor 32 when the bicycle stem 133 is viewed in the front-to-rear direction.

[0081] As a result, the torque sensor 30 is disposed above the steering column 3 in a position that overlaps with at least a portion of the anchor 32 when the bicycle stem 133 is viewed in the left-right or front-rear direction. In other words, the torque sensor 30 is prevented from being disposed so as to protrude significantly upward from the top of the steering column 3. Therefore, the torque sensor 30 can be disposed compactly in the up-down direction relative to the steering column 3.

[0082] Steering assist device 73 includes torque sensor 30 and bicycle steering assist motor unit 200. Bicycle steering assist motor unit 200 includes steering assist motor 11 and torque transmission mechanism 112. Torque transmission mechanism 112 is housed in casing 213 supported by a body frame (not shown).

[0083] As in the second embodiment, the torque transmitted portion 122 of the torque transmission mechanism 112 is fixed to the outer peripheral surface 3a of the steering column 3 by, for example, a fixing method using a clamp, or a fixing method in which a plurality of separate parts are arranged so as to sandwich the steering column 3 in the radial direction and connected by fastening members, etc. That is, as in the second embodiment, the torque transmitted portion 122 has a contact portion 122b.

[0084] The torque transmission portion 122 is sandwiched together with the steering column connection portion 135a in the axial direction of the steering column 3 between the top cap 31 of the stem mechanism 130 and a bearing portion 34 that rotatably supports the torque transmission portion 122 with respect to the head tube 61. Note that a bearing or the like (not shown) is disposed between the steering column connection portion 135a and the casing 213. This allows the steering column connection portion 135a to rotate with respect to the casing 213.

[0085] Note that the torque transmitted portion 122 may be sandwiched together with the steering column connecting portion 135a between the top cap 31 and the bearing portion 34 in the axial direction of the steering column 3 as described above, thereby transmitting the torque transmitted from the torque transmitting portion 121 to the steering column 3 and the steering column connecting portion 135a. Such torque transmission by the torque transmitted portion may be similarly realized in the configurations of the other embodiments.

[0086] (Embodiment 4) Figure 5 is a diagram showing an example of the configuration of a bicycle stem 33 provided with a torque sensor 30. Specifically, as shown in Figure 5, the bicycle stem 33 has a handlebar holder 234, a steering column holder 235, and the torque sensor 30. The handlebar holder 234 includes a handlebar connection portion (not shown).

[0087] The handle holding portion 234 and the steering column holding portion 235 are each connected to the torque sensor 30. The handle holding portion 234 is a rod-shaped member. One end of the handle holding portion 234 has a handle connection portion (not shown) that is connected to the handle 2. The other end of the handle holding portion 234 is connected to the torque sensor 30. The steering column holding portion 235 is a rod-shaped member. The other end of the steering column holding portion 235 has a steering column connection portion 235a that is connected to the steering column 3. One end of the steering column holding portion 235 is connected to the torque sensor 30. The handle connection portion and the steering connection portion 235a each have, for example, a clamp structure.

[0088] The steering column holding portion 235 is configured to space the torque sensor 30 and the handle holding portion 234 radially from the steering column 3 when viewed in the axial direction of the steering column 3. As a result, the handle 2 connected to the handle connecting portion of the handle holding portion 234 is also spaced radially from the steering column 3 when viewed in the axial direction of the steering column 3.

[0089] The handlebar holder 234, torque sensor 30, and steering column holder 235 are aligned in a straight line in the front-to-rear direction when viewed from above the bicycle stem 33. In other words, when viewed from the front-to-rear direction of the bicycle stem 33, the handlebar holder 234, torque sensor 30, and steering column holder 235 are arranged so that they overlap. This allows the torque sensor 30 to be positioned compactly in the left-to-right direction relative to the bicycle stem 33.

[0090] In the example shown in Figure 5 above, the torque sensor 30 is located in the front-rear direction relative to the steering column connection portion 235a. However, the torque sensor may also be located in the left-right direction relative to the steering column connection portion. In this case, the torque sensor may be located in a position where at least a portion of the torque sensor overlaps with the steering column connection portion when viewed from the left to right of the bicycle stem. This type of torque sensor location may also be applied to the configuration of embodiment 3.

[0091] 5, the steering column holding portion 235, the torque sensor 30, and the handle holding portion 234 are arranged in this order from the steering column 3 toward the steering wheel 2 in a top view: steering column holding portion 235, torque sensor 30, handle holding portion 234. However, as long as the torque sensor is located between the steering column holding portion and the handle holding portion, the steering column holding portion, torque sensor, and handle holding portion may be arranged in any order.

[0092] 5, the torque sensor 30 is located in front of the steering column 3. However, the torque sensor may be located behind the steering column, or to the left or right of the steering column.

[0093] 6 is a top view of the bicycle stem 33 and the bicycle steering assist motor unit 1. As shown in FIG. 6, at least a portion of the steering assist motor 11 of the bicycle steering assist motor unit 1 overlaps with the down tube 62 of the bicycle body frame 6 when viewed from above. In this embodiment, the width of the down tube 62 is wider than the width of the top tube 63.

[0094] This allows the bicycle steering assist motor unit 11 to be arranged compactly on the bicycle. The steering assist motor 11 is arranged above the down tube 62.

[0095] While the embodiments of the present invention have been described above, the above-described embodiments are merely examples for carrying out the present invention. Therefore, the present invention is not limited to the above-described embodiments, and can be practiced by appropriately modifying the above-described embodiments within the scope of the spirit thereof.

[0096] In each of the above-described embodiments, the torque transmission mechanism 12, 112 includes a torque transmission portion 21, 121 and a torque transmission receiving portion 22, 122. However, the torque transmission mechanism may include only a torque transmission receiving portion. In this case, the output torque of the steering assist motor is transmitted to the torque transmission receiving portion.

[0097] In the first and second embodiments, the steering column 3 extends in the vertical direction. However, the steering column may extend in an oblique direction, as in the third embodiment. The steering column of the third embodiment may also extend in the vertical direction, as in the first and second embodiments.

[0098] In the first and second embodiments, the steering assist motor 11 is located behind the steering column 3. In the third embodiment, the steering assist motor 11 is located in front of the steering column 3. However, the steering assist motor may be located in any position relative to the steering column, such as in front of, behind, to the left or right of the steering column, as long as it is located near the steering column.

[0099] In the first and second embodiments, the torque transmission portion 122 is located closer to the head tube 61 than the bicycle stem 33. However, the torque transmission portion may be located farther from the head tube than the bicycle stem.

[0100] In the second and third embodiments, the gear portion 122a of the torque transmission receiving portion 122 is, for example, fan-shaped or semicircular when viewed in the axial direction of the steering column 3. However, the gear portion of the torque transmission receiving portion may also be circular when viewed in the axial direction of the steering column.

[0101] In the third embodiment, the bicycle steering assist motor unit 200 has a torque transmission mechanism 112 having a configuration similar to that of the second embodiment. However, the torque transmission mechanism of the bicycle steering assist motor unit may have a configuration different from that of the second embodiment.

[0102] In the fourth embodiment, at least a portion of the steering assist motor 11 of the bicycle steering assist motor unit 1 overlaps with the down tube 62 of the bicycle body frame 6 when viewed from above. However, the steering assist motor does not have to overlap with the down tube of the bicycle body frame when viewed from above.

[0103] In the fourth embodiment, the steering assist motor 11 is disposed above the down tube 62. However, the steering assist motor may be disposed below the down tube. Also, the steering assist motor may be disposed inside the down tube as shown in FIG. 7 .

[0104] 7 is a left side view showing a schematic configuration of the bicycle Y in which the steering assist motor 311 and battery 312 are housed in the down tube 62. The battery 312 supplies power to the steering assist motor 311. Although not specifically shown, the bicycle steering assist motor unit 300 has a torque transmission mechanism for transmitting the output torque of the steering assist motor 311 to the steering column 3.

[0105] This improves the design of the bicycle Y equipped with the bicycle steering assist motor unit 300. Furthermore, by locating the steering assist motor 311 and the battery 312 inside the down tube 62, the center of gravity of the bicycle Y can be lowered.

[0106] The torque transmission mechanism may be housed in the down tube 62, the head tube 61, or may be disposed outside the body frame 6. In the example shown in Fig. 7, the steering assist motor 311 is disposed closer to the head tube 61 than the battery 312. However, the steering assist motor may be disposed farther from the head tube than the battery, or may be disposed at the same distance from the head tube as the battery. Furthermore, either the steering assist motor or the battery may be disposed outside the down tube or inside the top tube.

[0107] 1, 100, 200, 300 Bicycle steering assist motor unit 2 Handlebar 3 Steering column 3a Outer circumferential surface 3b Contact area 4 Front wheel 5 Rear wheel 6 Body frame 61 Head tube 62 Down tube 63 Top tube 7 Steering mechanism 71 Fork 11, 311 Steering assist motor 11a Output shaft 12, 112 Torque transmission mechanism 21, 121 Torque transmission portion 121a First gear portion 121b Second gear portion 22, 122 Torque transmitted portion 122a Gear portion 22a, 122b Contact portion 30 Torque sensor 31 Top cap 32 Anchor (pulling member) 33, 133 Bicycle stem 34 Bearing portion 73 Steering assist device 13, 113, 213 Casing 130 Stem mechanism 134, 234 Handle holder 135, 235 Steering column holder 135a, 235a Steering column connection part 312 Battery X, Y Bicycle P Axis

Claims

1. A motor unit for bicycle steering assist comprising: a steering assist motor that assists steering of a bicycle handlebar; and a torque transmission mechanism that transmits the output torque of the motor to a steering column pulled up in the axial direction by a pulling member, wherein the torque transmission mechanism is connected to the outer peripheral surface of the steering column and has a torque transmitted portion that transmits the output torque of the steering assist motor to the steering column, and the torque transmitted portion has a contact portion that applies pressure radially to a contacted area extending circumferentially and axially on the outer peripheral surface of the steering column to transmit the output torque of the motor to the steering column by frictional force generated between the steering column and the torque transmitted portion.

2. A motor unit for assisting steering of a bicycle as described in claim 1, wherein the steering assist motor is arranged in a position where, when viewed in the vertical direction, at least a portion of the steering assist motor overlaps with a down tube that constitutes part of the body frame of the bicycle.

3. A motor unit for assisting steering of a bicycle as claimed in claim 1 or 2, further comprising a battery for supplying power to the steering assist motor, the steering assist motor and the battery being housed within the down tube.

4. A motor unit for bicycle steering assist as described in any one of claims 1 to 3, wherein the torque transmission portion has a cylindrical steering column connection portion capable of contacting the outer circumferential surface of the steering column while applying radial pressure, and the contact portion is part of the inner circumferential surface of the steering column connection portion.

5. A bicycle equipped with a motor unit for assisting bicycle operation according to any one of claims 1 to 4.

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