Bicycle stem and bicycle provided with same

Abstract

A torque sensor 30 of a bicycle stem 1 has a configuration in which when the same torque is input around X-, Y-, and Z-axes that are orthogonal to each other, and in which deformation is more easily caused by the torque around the X-axis than by the torque around the Y-axis or the torque around the Z-axis. The bicycle stem 1 comprises: a first stem 10 that includes a handle connection section 11 connected to a handle 2, and a first torque sensor connection section 12 connected to the torque sensor 30; and a second stem 20 that includes a steering column connection section 21 connected to a steering column 3, and a second torque sensor connection section 22 connected to the torque sensor 30. The first stem 10 and the second stem 20 are configured such that the handle connection section 11 is located further forward than the steering column 3, and are also configured such that deformation is less likely to occur therein than in the torque sensor 30 when the same torque is input around the X-axis.

Description

Bicycle stem and bicycle equipped with same

[0001] The present invention relates to a bicycle stem and a bicycle equipped with the same.

[0002] A bicycle stem is a known component that connects a bicycle's steering column to the handlebars. Generally, a bicycle stem includes an ahead stem and a threaded stem. The ahead stem is directly connected to the top of the steering column. The threaded stem is connected to the steering column by pressing a fixing member at its lower end against the inner surface of the top of the steering column.

[0003] Recently, bicycles have become known that are equipped with steering assist devices to assist in steering. For example, Patent Document 1 discloses an electric power steering control system that receives signals from a torque sensor that detects the torque of the input shaft and a vehicle speed sensor that detects the vehicle speed, and controls an assist motor and a magnetic clutch to achieve an electric power steering function.

[0004] For example, Patent Document 2 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 front wheel of the bicycle, and a controller that acquires values ​​from the sensor, and the controller adjusts the steering angle using the steering control assembly based on the values ​​from the sensor.

[0005] It should be noted that the above-mentioned Patent Document 2 discloses that the torque sensor is attached between the stem of the handlebar and the steering tube of the bicycle frame.

[0006] For example, Patent Document 3 discloses a bicycle power meter having at least one strain gauge arranged on the outer peripheral wall of the stem, the inner peripheral wall of the stem, or both the outer peripheral wall and the inner peripheral wall of the stem, a signal processing unit, a processor, and a signal transmitter.

[0007] Chinese Patent Application Publication No. 10311254 US Patent Application Publication No. 2020 / 0102043 US Patent Application Publication No. 2021 / 0396614

[0008] As disclosed in the above-mentioned Patent Documents 1 and 2, configurations including torque sensors for assisting bicycle steering are known. However, neither of these documents discloses specific configurations for the torque sensor, such as the arrangement and mounting structure of the torque sensor.

[0009] As mentioned above, when assisting the steering of a bicycle, it is preferable that the torque sensor has directionality so that it can accurately detect torque in the direction of rotation of the steering column.

[0010] In contrast, the above-mentioned Patent Document 3 discloses a strain gauge disposed on the outer peripheral wall of the stem, the inner peripheral wall of the stem, or both the outer peripheral wall and the inner peripheral wall of the stem. Although Patent Document 3 discloses that the strain gauge can measure the deformation (strain) occurring in the stem, it does not disclose anything about measuring the deformation of the stem in a directional manner.

[0011] Therefore, there is a demand for a bicycle stem in which a torque sensor is compactly mounted so that the measurement direction is directional, taking advantage of the shape and function of the stem.

[0012] The present invention aims to provide a bicycle stem in which a torque sensor is compactly mounted so that the torque sensor has directionality in the measurement direction, by utilizing the shape and function of the stem.

[0013] The inventors have investigated the possibility of utilizing the shape and function of a bicycle stem to provide a torque sensor on the bicycle stem so that the torque sensor has directionality in the measurement direction.

[0014] First, the inventors focused on the fact that a bicycle stem is a component that connects a steering column and a handlebar. That is, the bicycle stem has a steering column connection portion that connects to the steering column and a handlebar connection portion that connects to the handlebar. Furthermore, when viewed axially of the steering column, the steering column connection portion and the handlebar connection portion of the bicycle stem are located apart in the radial direction of the steering column.

[0015] The inventors also focused on the fact that the bicycle stem has higher rigidity than the handlebars. Taking advantage of the fact that the handlebars have lower rigidity than the bicycle stem, the inventors first considered attaching strain gauges to the handlebars to easily detect torque acting on the handlebars. However, the torque detected by strain gauges attached to the handlebars includes torque in directions other than the steering direction of the handlebars. Therefore, there is a possibility that steering torque may not be detected accurately.

[0016] Next, the inventors considered attaching a strain gauge to the bicycle stem and using the strain gauge to detect steering torque. In this case, the strain gauge would need to accurately detect even minute deformations in the bicycle stem. However, it is difficult to accurately detect minute deformations in the bicycle stem using the strain gauge.

[0017] In consideration of the above, the inventors came up with the idea of ​​dividing the bicycle stem into a first stem and a second stem and placing a torque sensor between them, thereby taking advantage of the high rigidity of the bicycle stem to accurately detect only steering torque with the torque sensor. In other words, by placing the torque sensor between the two stems, they came up with a bicycle stem configuration in which steering torque causes the first stem and the second stem to displace relative to each other in one direction, making it easier for the torque sensor to detect steering torque, and the high rigidity of the bicycle stem makes it less likely to deform in another direction due to torque other than steering torque.

[0018] Specifically, the inventors have come up with the following configuration for disposing a torque sensor on a bicycle stem: That is, the inventors have come up with a configuration in which the stem includes a first stem having a steering column connection portion connected to a steering column and a first torque sensor connection portion connected to the torque sensor, and a second stem having a handlebar connection portion connected to a handlebar and a second torque sensor connection portion connected to the torque sensor. Furthermore, the inventors have also come up with the idea that the handlebar connection portions of the first stem and the second stem are configured to be located forward of the steering column, and are configured to be less susceptible to deformation than the torque sensor when the same torque is input around the X axis.

[0019] As a result of the above-mentioned intensive investigations, the present inventors have come up with the following configuration.

[0020] One embodiment of the present invention provides a bicycle stem equipped with a torque sensor. The torque sensor is configured to detect torque around the X-axis when a force is input from the handlebars or steering column, such that when the same torque is input around each of the orthogonal X, Y, and Z axes, the torque sensor is more likely to deform when subjected to torque around the X-axis than when subjected to torque around the Y-axis or Z-axis. The bicycle stem includes a first stem having a steering column connection portion connected to the steering column and a first torque sensor connection portion connected to the torque sensor, and a second stem having a handlebar connection portion connected to the handlebars and a second torque sensor connection portion connected to the torque sensor. The handlebar connection portions of the first and second stems are configured to be located forward of the steering column, and are configured to be less likely to deform than the torque sensor when the same torque is input around the X-axis.

[0021] A bicycle stem is a component that connects a handlebar to a steering column in a torque-transmitting manner. In the bicycle stem, the steering column connection portion and the handlebar connection portion are located apart in the radial direction of the steering column when viewed axially of the steering column.

[0022] For such a member, as described above, the stem is divided into two, a first stem and a second stem, and a torque sensor is provided between the first stem and the second stem. As a result, when the same torque is input around the X-axis to the first stem and the second stem, which are respectively connected to the torque sensor, the torque sensor is more likely to deform than the first stem and the second stem. This increases the signal-to-noise ratio of the torque signal detected by the torque sensor. This improves the torque detection accuracy of the torque sensor.

[0023] Furthermore, the torque sensor is connected to the first stem and the second stem, respectively, and constitutes a part of the stem. Therefore, the torque sensor is positioned relative to the first stem connected to the steering column and the second stem connected to the handlebars. Therefore, the above-mentioned configuration has less variation in the sensor mounting position compared to when multiple sensors are provided, thereby improving the torque detection accuracy.

[0024] Therefore, it is possible to realize a bicycle stem that utilizes the functions of the stem while improving the accuracy of torque detection by the torque sensor.

[0025] According to another aspect, the bicycle stem of the present invention may include the following configuration: The X-axis extends in the left-right, up-down, or front-back direction.

[0026] By positioning the torque sensor relative to the stem in accordance with the bicycle's usage scenario, torque detection by the torque sensor can be performed taking into account the usage scenario, thereby increasing the signal-to-noise ratio of the torque signal detected by the torque sensor and improving the torque detection accuracy of the torque sensor.

[0027] According to another aspect, the bicycle stem of the present invention may include the following configuration: The first stem is spaced apart from the second stem in the X-axis direction.

[0028] This makes it easier for the first stem and the second stem to be displaced relative to each other by torque input around the X-axis, so that the torque sensor can more easily detect the torque input to the first stem and the second stem.

[0029] From another perspective, the bicycle stem of the present invention may include the following configuration: An X-axis direction movement restriction portion is provided between the first stem and the second stem, which restricts relative movement of the first stem and the second stem in the X-axis direction beyond a predetermined amount.

[0030] This prevents the first stem and the second stem from moving relative to each other in the X-axis direction by more than a predetermined amount, which would cause a decrease in the performance or measurement accuracy of the torque sensors connected to the first stem and the second stem, respectively.

[0031] From another perspective, the bicycle stem of the present invention may include the following configuration: An X-axis rotation restricting portion is provided between the first stem and the second stem, which restricts relative rotation of the first stem and the second stem about the X-axis by more than a predetermined angle.

[0032] This prevents the first stem and the second stem from rotating relative to each other by more than a predetermined angle around the X axis, which would cause a decrease in the performance or measurement accuracy of the torque sensors connected to the first stem and the second stem, respectively.

[0033] According to another aspect, the bicycle stem of the present invention may include the following configuration: the first stem and the second stem are configured such that, when viewed in the axial direction of the steering column, the handlebar connection portion, the first torque sensor connection portion, the second torque sensor connection portion, and the steering column connection portion are aligned in the fore-and-aft direction.

[0034] In this configuration, a torque sensor is provided between the first torque sensor connection portion of the first stem and the second torque sensor connection portion of the second stem. The steering column connection portion of the first stem and the handle connection portion of the second stem are located radially outward from the steering column when viewed in the axial direction of the steering column. The torque sensors thus arranged with respect to the first stem and the second stem can detect torque applied to the handle or the steering column.

[0035] Furthermore, with the above-described configuration, the steering column connection portion, the first torque sensor connection portion, the handlebar connection portion, and the second torque sensor connection portion are aligned in the front-to-rear direction when viewed in the axial direction of the steering column, which allows the torque sensor to be positioned compactly in the left-to-right direction relative to the bicycle stem.

[0036] Therefore, by utilizing the configuration and function of the bicycle stem, the torque sensor can be arranged compactly on the bicycle stem.

[0037] According to another aspect, the bicycle stem of the present invention may include the following configuration: the first torque sensor connection portion of the first stem or the second torque sensor connection portion of the second stem is connected to a case of the torque sensor.

[0038] This allows the first stem or the second stem to be connected to a torque sensor, and the torque applied to the first stem or the second stem can be detected with high precision by the torque sensor.

[0039] According to another aspect, the bicycle stem of the present invention may include the following configuration: the first torque sensor connecting portion of the first stem or the second torque sensor connecting portion of the second stem is integrally formed with at least a portion of a case of the torque sensor.

[0040] This allows the first stem or the second stem to be connected to a torque sensor, and the torque applied to the first stem or the second stem can be detected with high precision by the torque sensor.

[0041] A bicycle according to one embodiment of the present invention includes a bicycle stem having the above-described configuration. In the bicycle, a torque sensor can be provided in a compact manner by utilizing the shape and function of the stem.

[0042] The terminology used in this specification is used for the purpose of defining particular embodiments only, and is not intended to limit the invention.

[0043] As used herein, "and / or" includes all combinations of one or more of the associated listed members.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] In this specification, an embodiment of a bicycle stem according to the present invention will be described.

[0051] 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.

[0052] 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.

[0053] [Bicycle Stem] In this specification, a bicycle stem is a component that connects the handlebars of a bicycle to a steering column that passes through the head tube. The bicycle stem includes an ahead stem that is directly connected to the top of the steering column, and a threaded stem that is connected to the steering column by pressing a fixing member at its lower end against the inner surface of the top of the steering column. The bicycle may be a two-wheeled vehicle or a three-wheeled vehicle, as long as the rider obtains driving force by rotating the pedals. The bicycle may be a vehicle that leans left and right, or a vehicle that does not lean left and right.

[0054] [Steering column] In this specification, the steering column is a part of a bicycle that is rotatably housed in the head tube and connected to the fork that rotatably supports the front wheel. The steering column is connected to a steering column connection part of the bicycle stem.

[0055] [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 central portion of the handlebar.

[0056] [Around the X-axis, Around the Y-axis, Around the Z-axis] In this specification, around the X-axis means the direction of rotation around the X-axis. Around the Y-axis means the direction of rotation around the Y-axis. Around the Z-axis means the direction of rotation around the Z-axis. The X-axis, Y-axis, and Z-axis are axes that extend in directions perpendicular to each other. The X-axis is, for example, an axis parallel to the axis of the steering column.

[0057] [X-axis direction, Y-axis direction, Z-axis direction] In this specification, the X-axis direction means the direction in which the X-axis extends. The Y-axis direction means the direction in which the Y-axis extends. The Z-axis direction means the direction in which the Z-axis extends.

[0058] In this specification, "in a straight line" means that the handlebar connection part, torque sensor, and steering column connection part are aligned in a straight line within a predetermined range when viewed in the axial direction of the steering column. In other words, in this straight line, the handlebar connection part, torque sensor, and steering column connection part are arranged in overlapping positions when viewed in the front-to-rear direction of the bicycle.

[0059] [Front-rear direction] In this specification, the term "front-rear direction" refers to the front-rear direction as seen by a rider riding a bicycle with a bicycle stem attached to the bicycle.

[0060] [Left-right direction] In this specification, the left-right direction means the left-right direction as seen by a rider riding a bicycle with a bicycle stem attached to the bicycle.

[0061] [Up-down direction] In this specification, the up-down direction means the up-down direction as seen by a rider riding a bicycle with a bicycle stem attached to the bicycle.

[0062] According to one embodiment of the present invention, by utilizing the shape and function of the stem, it is possible to realize a stem in which a torque sensor is compactly provided so as to have directionality in the measurement direction.

[0063] FIG. 1 is a plan view showing the schematic configuration of a bicycle stem according to a first embodiment. FIG. 2 is a left side view showing the schematic configuration of the bicycle stem. FIG. 3 is a rear view showing the schematic configuration of the bicycle stem. FIG. 4 is a left side view showing an example of the arrangement of a steering assist motor. FIG. 5 is a left side view showing the schematic configuration of a bicycle. FIG. 6 is a left side view showing the schematic configuration of a bicycle stem according to a third embodiment. FIG. 7 is a plan view showing the schematic configuration of a bicycle stem according to the third embodiment. FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 7. FIG. 9 is a left side view showing an example of the arrangement of a torque sensor in a bicycle stem according to another embodiment. FIG. 10 is a diagram showing an example of the arrangement of a torque sensor in a bicycle stem according to another embodiment.

[0064] 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.

[0065] 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.

[0066] (Embodiment 1) A bicycle stem 1 according to Embodiment 1 of the present invention will be described using Figures 1 to 3. Figure 1 is a plan view showing the general configuration of the bicycle stem 1 according to Embodiment 1. Figure 2 is a left side view showing the general configuration of the bicycle stem 1. Figure 3 is a rear view showing the general configuration of the bicycle stem 1.

[0067] The bicycle stem 1 is a component that connects the bicycle handlebars 2 and the steering column 3. As shown in Figures 1 and 2, the bicycle stem 1 has a first stem 10 having a handlebar connection portion 11 that connects to the handlebars 2, and a second stem 20 having a steering column connection portion 21 that connects to the steering column 3.

[0068] More specifically, the bicycle stem 1 has a first stem 10, a second stem 20, and a torque sensor 30. The first stem 10 includes a handlebar connection portion 11. The second stem 20 includes a steering column connection portion 21.

[0069] The first stem 10 and the second stem 20 are each connected to a torque sensor 30. The torque sensor 30 is a sensor for detecting torque input to the handle 2 or the steering column 3. The torque detected by the torque sensor 30 is used, for example, to control the drive of a motor (not shown) for applying a steering assist force to the steering column 3.

[0070] The torque sensor 30 is configured to be able to accurately detect torque input around the X-axis. That is, when the same torque is input around the orthogonal X, Y, and Z axes, the torque sensor 30 is configured to detect torque around the X-axis when a force is input to the bicycle stem 1 from the handlebars 2 or steering column 3. In this embodiment, the X-axis is an axis parallel to the axis of the steering column 3. The Y-axis and Z-axis are each orthogonal to the X-axis.

[0071] The first stem 10 is a rod-shaped member. One end of the first stem 10 has a handle connection portion 11 that is connected to the handle 2. The handle connection portion 11 has, for example, a clamp structure. The other end of the first stem 10 has a first torque sensor connection portion 12 that is connected to the torque sensor 30.

[0072] The handle connecting portion 11 may have a structure other than a clamp structure as long as it can be connected to the handle 2. The first torque sensor connecting portion 12 may have a detachable structure such as a fastening member such as a bolt or a fitting, or may have a non-detachable structure such as a joint or adhesive. The first torque sensor connecting portion 12 may be connected to a case of the torque sensor 30. In this case, the torque sensor 30 can detect rotation about the X-axis by relative rotation of the portion of the torque sensor 30 to which the second torque sensor connecting portion 22 is connected with respect to the case.

[0073] The second stem 20 is a rod-shaped member. The second stem 20 has, at the other end thereof, a steering column connection portion 21 that is connected to the steering column 3. The steering column connection portion 21 has, for example, a clamp structure. The second stem 20 has, at one end thereof, a second torque sensor connection portion 22 that is connected to the torque sensor 30.

[0074] The second stem 20 is configured to space the torque sensor 30 and the first stem 10 radially apart 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 connection portion 11 of the first stem 10 is also spaced radially from the steering column 3 when viewed in the axial direction of the steering column 3. In this embodiment, the first stem 10 is spaced from the second stem 20 in the front-to-rear direction.

[0075] It should be noted that the steering column connection portion 21 may have a structure other than a clamp structure as long as it can be connected to the steering column 3. The second torque sensor connection portion 22 may have a detachable structure such as a fastening member such as a bolt or a fitting, or may have a non-detachable structure such as a joint or adhesive. The second torque sensor connection portion 22 may be connected to a case of the torque sensor 30. In this case, the torque sensor 30 can detect rotation about the X-axis by the portion of the torque sensor 30 to which the first torque sensor connection portion 12 is connected rotating relative to the case.

[0076] The first stem 10 and the second stem 20 are configured so that the handle connection portion 11 is located forward of the steering column 3, and are configured so that when the same torque is input around the X axis, the first stem 10 and the second stem 20 are less likely to deform than the torque sensor 30. In other words, when the same torque is input around the X axis to the first stem 10, the second stem 20, and the torque sensor 30, the torque sensor 30 is more likely to deform than the first stem 10 and the second stem 20.

[0077] As described above, the bicycle stem 1 of this embodiment is a so-called ahead stem, which is connected to the outer peripheral surface of the steering column 3 in a direction intersecting the axis P of the steering column 3.

[0078] Because at least one of the first stem 10 and the second stem 20 has a detachable connection structure for the torque sensor 30, it becomes possible to change at least one of the front-to-rear and up-to-down positions of the handlebars 2 relative to the steering column 3 by replacing at least one of the first stem 10 and the second stem 20. This makes it easy to change at least one of the front-to-rear and up-to-down positions of the handlebars 2 relative to the steering column 3. Therefore, while providing the torque sensor 30 on the bicycle stem 1, it is possible to ensure the stem's function of adjusting the position of the handlebars 2 relative to the steering column 3.

[0079] The first stem 10, torque sensor 30, and second stem 20 are aligned in a straight line when the bicycle stem 1 is viewed from above. That is, as shown in Figure 3, the first stem 10, torque sensor 30, and second stem 20 are arranged so that they overlap when the bicycle stem 1 is viewed from the front to the rear. For the sake of illustration, the torque sensor 30 is shown with diagonal lines in Figure 3. When the bicycle stem 1 is viewed from the front to the rear, the torque sensor 30 is positioned so that it overlaps with at least a portion of the steering column connection portion 21. This allows the torque sensor 30 to be positioned compactly in the left-right direction relative to the bicycle stem 1.

[0080] The bicycle stem 1 according to this embodiment includes a torque sensor 30. The torque sensor 30 is configured to detect torque around the X-axis when a force is input from the handlebars 2 or the steering column 3. When the same torque is input around the orthogonal X, Y, and Z axes, the torque sensor 30 is more likely to deform due to torque around the X-axis than torque around the Y-axis and Z-axis. The bicycle stem 1 includes a first stem 10 having a handlebar connection portion 11 connected to the handlebars 2 and a first torque sensor connection portion 12 connected to the torque sensor 30, and a second stem 20 having a steering column connection portion 21 connected to the steering column 3 and a second torque sensor connection portion 22 connected to the torque sensor 30. The first stem 10 and the second stem 20 are configured so that the handlebar connection portion 11 is located forward of the steering column 3, and are configured to be less likely to deform than the torque sensor 30 when the same torque is input around the X-axis.

[0081] As described above, the stem is divided into two, the first stem 10 and the second stem 20, and the torque sensor 30 is provided between the first stem 10 and the second stem 20. As a result, when the same torque around the X-axis is input to the first stem 10 and the second stem 20, which are respectively connected to the torque sensor 30, the torque sensor 30 is more likely to deform than the first stem 10 and the second stem 20. This makes it possible to increase the signal-to-noise ratio of the torque signal detected by the torque sensor 30. This therefore improves the torque detection accuracy of the torque sensor 30.

[0082] Moreover, the torque sensor 30 is connected to each of the first stem 10 and the second stem 20, and constitutes a part of the stem. Therefore, the torque sensor 30 is positioned relative to the first stem 10 connected to the handlebar 2 and the second stem 20 connected to the steering column 3. Therefore, the above-mentioned configuration has less variation in the sensor mounting position compared to when multiple sensors are provided, and therefore the torque detection accuracy can be improved.

[0083] Therefore, it is possible to realize a bicycle stem 1 that can improve the torque detection accuracy of the torque sensor 30 while utilizing the functions of the stem.

[0084] Furthermore, the first stem 10 and the second stem 20 are configured so that, when viewed in the axial direction of the steering column 3, the handle connection portion 11, the first torque sensor connection portion 12, the steering column connection portion 21, and the second torque sensor connection portion 22 are aligned in the fore-and-aft direction.

[0085] In this configuration, a torque sensor 30 is provided between the first torque sensor connection portion 12 of the first stem 10 and the second torque sensor connection portion 22 of the second stem 20. The handle connection portion 11 of the first stem 10 and the steering column connection portion 21 of the second stem 20 are located radially outward from the steering column 3 when viewed in the axial direction of the steering column 3. The torque sensor 30 thus arranged with respect to the first stem 10 and the second stem 20 can detect the torque applied to the handle 2 or the steering column 3.

[0086] Furthermore, with the above-described configuration, the handlebar connection portion 11, the first torque sensor connection portion 12, the second torque sensor connection portion 22, and the steering column connection portion 21 are aligned in the front-to-rear direction when viewed in the axial direction of the steering column 3. This allows the torque sensor 30 to be positioned compactly in the left-to-right direction relative to the bicycle stem 1.

[0087] Therefore, by utilizing the configuration and function of the bicycle stem 1, the torque sensor 30 can be arranged compactly on the bicycle stem 1.

[0088] In this embodiment, the first torque sensor connection portion 12 of the first stem 10 or the second torque sensor connection portion 22 of the second stem 20 may be connected to the case of the torque sensor 30.

[0089] This allows the first stem 10 or the second stem 20 to be connected to the torque sensor 30, and the torque applied to the first stem 10 or the second stem 20 can be detected with high accuracy by the torque sensor 30.

[0090] In addition, in this embodiment, the first torque sensor connection portion 12 of the first stem 10 or the second torque sensor connection portion 22 of the second stem 20 may be formed integrally with at least a portion of the case of the torque sensor 30.

[0091] This allows the first stem 10 or the second stem 20 to be connected to the torque sensor 30, and the torque applied to the first stem 10 or the second stem 20 can be detected with high accuracy by the torque sensor 30.

[0092] (Embodiment 2) Figure 4 is a left side view showing an example of the arrangement of a steering assist motor 77 that applies a steering assist force to the steering column 3 connected to the bicycle stem 1. As shown in Figure 4, the steering assist motor 77 is connected to the steering column 3 via a torque transmission mechanism 78 so as to be able to transmit torque.

[0093] The steering assist motor 77 is driven by a control device (not shown) based on the torque detected by the torque sensor 30. The torque output from the steering assist motor 77 is transmitted to the steering column 3 via a torque transmission mechanism 78. The steering assist motor 77 is located in front of the steering column 3. Although not specifically shown, the steering assist motor 77 is supported by the body frame of the bicycle.

[0094] The steering assist motor 77 is disposed in front of the steering column 3. The steering assist motor 77 may be disposed in any position relative to the steering column 3, such as behind, to the left, or to the right of the steering column 3, as long as it is disposed close to the steering column 3. Although not specifically shown, the steering assist motor 77 is supported by the bicycle body frame.

[0095] The torque transmission mechanism 78 is connected to the steering assist motor 77 and the steering column 3 so as to be able to transmit the torque output from the steering assist motor 77 to the steering column 3. The torque transmission mechanism 78 may be configured in any way, such as a gear, a pulley, a link, a belt, a chain, a sprocket, or the like, as long as it is able to transmit the torque of the steering assist motor 77 to the steering column 3.

[0096] 4, reference numeral 72 denotes a stem mechanism. The stem mechanism 72 includes the bicycle stem 1, an anchor 75, and a top cap 76.

[0097] The anchor 75 is disposed inside the upper part of the steering column 3. The lower part of the top cap 76 is rotatably connected to the upper part of the anchor 75. The anchor 75 is configured to expand radially and press against the inner peripheral surface of the steering column 3 using a tool (not shown). The anchor 75 makes it possible to pull up the steering column 3 in the axial direction relative to the bicycle body frame (not shown). The anchor 75 corresponds to a pulling-up member.

[0098] The torque sensor 30 is positioned so as to overlap at least a portion of the anchor 75 when the bicycle stem 1 is viewed in the front-to-rear direction.

[0099] 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 75 when the bicycle stem 1 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 vertical direction relative to the steering column 3.

[0100] (Embodiment 3) Figure 5 is a left side view showing the schematic configuration of a bicycle T having a bicycle stem 100. The bicycle T according to this embodiment is, for example, a two-wheeled vehicle. The bicycle T 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.

[0101] The steering mechanism 7 has a fork portion 71, a steering column 3, a stem mechanism 72, 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.

[0102] The fork portion 71 rotatably supports the front wheel 4 at its lower end. The steering column 3 is connected to the upper end of the fork portion 71. The steering column 3 passes through the head tube 61 of the body frame 6. A stem mechanism 72 is attached to the upper end of the steering column 3. The handlebars 2 are supported by the stem mechanism 72. 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.

[0103] Figure 6 is a left side view showing the schematic configuration of the stem mechanism 72 and the steering assist device 73. Figure 7 is a plan view showing the schematic configuration of the stem mechanism 72 and the steering assist device 73. Figure 8 is a cross-sectional view taken along line VIII-VIII in Figure 7. The stem mechanism 72 has a bicycle stem 100, an anchor 75, and a top cap 76.

[0104] The bicycle stem 100 has a first stem 110, a torque sensor 30, a second stem 120, and a movement restricting portion 130.

[0105] The first stem 110 has a handle connection portion 111 at one end thereof. The handle 2 is connected to the handle connection portion 111. The first stem 110 has a first torque sensor connection portion 112 at the other end thereof, which is connected to the torque sensor 30.

[0106] The second stem 120 has, at one end, a steering column connection portion 121. The steering column 3 is connected to the steering column connection portion 121. The second stem 120 has, at the other end, a second torque sensor connection portion 122 that is connected to the torque sensor 30.

[0107] The torque sensor 30 is located behind the steering column 3. Therefore, the second stem 120 is connected to the steering column 3 so as to extend rearward. The first stem 110 is located axially outward from 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. The first stem 110 is spaced apart from the second stem 120 in the axial direction of the steering column 3, i.e., in the X-axis direction.

[0108] The movement restricting portion 130 restricts the first stem 110 and the second stem 120 from moving relative to each other in the X-axis direction by more than a predetermined amount, and also restricts the first stem 110 and the second stem 120 from rotating around the X-axis by more than a predetermined angle.

[0109] Specifically, the movement restricting portion 130 has a restricting pin 131, a cylindrical elastic member 132, and a retaining member 133. The restricting pin 131 penetrates the first stem 110 in the X-axis direction, and one end is fixed to the second stem 120. The other end of the restricting pin 131 protrudes upward beyond the first stem 110. The elastic member 132 is made of a material that is elastically deformable in the radial direction. The elastic member 132 is arranged so as to cover the portion of the restricting pin 131 that penetrates the first stem 110. In other words, the restricting pin 131 and the elastic member 132 penetrate the first stem 110 in the X-axis direction.

[0110] A retaining member 133 is attached to the other end of the restriction pin 131 protruding upward from the first stem 110. The retaining member 133 may be a C-shaped member attached to a groove (not shown) formed on the outer circumferential surface of the restriction pin 131 so as to extend in the circumferential direction, or may be an annular member fitted onto the outer circumferential surface of the restriction pin 131.

[0111] With the above-described configuration, when the first stem 110 and the second stem 120 attempt to move relatively in the X-axis direction by a predetermined amount or more, the relative movement of the first stem 110 and the second stem 120 is restricted by the retaining member 133 attached to the other end of the restricting pin 131 of the movement restricting unit 130. Therefore, in this case, the movement restricting unit 130 functions as an X-axis direction movement restricting unit. The predetermined amount means a movement amount that would degrade the performance or measurement accuracy of the torque sensor 30 when the first stem 110 and the second stem 120 move relatively in the X-axis direction.

[0112] Furthermore, with the above-described configuration, when the first stem 110 and the second stem 120 attempt to rotate relatively around the X axis by a predetermined angle or more, the restriction pin 131 of the movement restriction unit 130 restricts the relative rotation between the first stem 110 and the second stem 120. Therefore, in this case, the movement restriction unit 130 functions as an X-axis rotation restriction unit. The predetermined angle means an amount of movement that would degrade the performance or measurement accuracy of the torque sensor 30 when the first stem 110 and the second stem 120 rotate relatively around the X axis.

[0113] The steering assist device 73 has a torque sensor 30 , a steering assist motor 77 , and a torque transmission mechanism 78 .

[0114] The torque sensor 30 is positioned so as to overlap at least a portion of the anchor 75 when the bicycle stem 100 is viewed in the front-to-rear direction.

[0115] 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 75 when the bicycle stem 100 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. This allows the torque sensor 30 to be disposed compactly in the vertical direction relative to the steering column 3.

[0116] Furthermore, the first stem 110 is spaced apart from the second stem 120 in the X-axis direction. This makes it easier for the first stem 110 and the second stem 120 to be displaced relative to each other by torque input around the X-axis. This allows the torque sensor 30 to more easily detect the torque input to the first stem 110 and the second stem 120.

[0117] 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.

[0118] In each of the above embodiments, the bicycle stem 1, 100 is an ahead stem. However, the bicycle stem may also be a threaded stem that is connected to the steering column by pressing a fixing member at the lower end against the inner surface of the upper part of the steering column.

[0119] In each of the above embodiments, the X-axis is an axis parallel to the axis P of the steering column. However, the X-axis may extend in the up-down direction, the front-rear direction, or the left-right direction. This makes it possible to detect various torques input to the handlebars or the steering column using a torque sensor that can easily detect torque around the X-axis. Therefore, by positioning the torque sensor relative to the stem in accordance with the bicycle's usage scenario, torque detection by the torque sensor can be performed taking into account the usage scenario. This increases the signal-to-noise ratio of the torque signal detected by the torque sensor, thereby improving the torque detection accuracy of the torque sensor.

[0120] In each of the above embodiments, the torque sensor 30 is located in the front-to-rear direction relative to the steering column connection portion 21, 121. However, the torque sensor may also be located in the left-to-right direction relative to the steering column connection portion. In this case, the torque sensor may be positioned so that 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.

[0121] The torque sensor may also be positioned so that a portion of it overlaps the second stem when viewed in the front-to-rear direction of the bicycle stem. Figures 9 and 10 are schematic diagrams showing a state in which the torque sensor 30 is positioned so that a portion of it overlaps the second stem 220, 320 when viewed in the front-to-rear direction of the bicycle stem 200, 300. The entire torque sensor 30 does not have to overlap the second stem 220, 320 when viewed in the front-to-rear direction of the bicycle stem 200, 300. In Figure 9, reference numeral 210 denotes the first stem.

[0122] In the first and second embodiments, in the bicycle stem 1, 100, the second stem 20, 120, torque sensor 30, and first stem 10, 110 are arranged in this order from the steering column 3 toward the handlebars 2 in a top view: second stem 20, 120, torque sensor 30, first stem 10, 110. However, as long as the torque sensor is located between the second stem and the first stem, the second stem, torque sensor, and first stem may be arranged in any order.

[0123] In the first and second embodiments, the torque sensor 30 is located in front of the steering column 3. However, the torque sensor may be located behind the steering column 3, or to the left or right of the steering column.

[0124] 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.

[0125] In the third embodiment, the torque sensor 30 is positioned so as to overlap at least a portion of the anchor 75 when the bicycle stem 100 is viewed in the front-to-rear direction. However, the torque sensor may also be positioned so as to overlap at least a portion of the anchor when the bicycle stem is viewed in the left-to-right direction.

[0126] In the third embodiment, the steering assist motor 77 is located in front of the steering column 3. However, the steering assist motor may be located at any position relative to the steering column, as long as it is located near the steering column, such as behind, to the left, or to the right of the steering column.

[0127] In the third embodiment, the bicycle stem 100 includes a movement restricting portion 130. However, the bicycle stem does not necessarily have to include a movement restricting portion. Furthermore, the movement restricting portion may function as an X-axis rotation restricting portion without functioning as an X-axis movement restricting portion. The movement restricting portion may function as an X-axis movement restricting portion without functioning as an X-axis rotation restricting portion. The movement restricting portion may have a configuration other than that shown in the third embodiment, as long as it can fulfill the functions of at least one of an X-axis movement restricting portion or an X-axis rotation restricting portion.

[0128] REFERENCE SIGNS LIST 1, 100, 200, 300 Bicycle stem 2 Handlebar 3 Steering column 4 Front wheel 5 Rear wheel 6 Body frame 7 Steering mechanism 10, 110, 210 First stem 11, 111 Handlebar connection portion 12, 112 First torque sensor connection portion 20, 120, 220, 320 Second stem 21, 121 Steering column connection portion 22, 122 Second torque sensor connection portion 30 Torque sensor 61 Head tube 71 Fork portion 72 Stem mechanism 73 Steering assist device 75 Anchor (pulling member) 76 Top cap 77 Steering assist motor 78 Torque transmission mechanism 130 Movement restriction portion 131 Restriction pin 132 Elastic member 133 Retaining member T Bicycle P Axis

Claims

1. A bicycle stem equipped with a torque sensor, wherein the torque sensor is configured to detect torque around the X-axis when a force is input from a handlebar or a steering column, and is more likely to deform due to a torque around the X-axis than a torque around the Y-axis and a torque around the Z-axis when the same torque is input around each of the orthogonal X, Y and Z axes; the bicycle stem comprises: a first stem having a handlebar connection portion connected to the handlebar and a first torque sensor connection portion connected to the torque sensor; and a second stem having a steering column connection portion connected to the steering column and a second torque sensor connection portion connected to the torque sensor, wherein the handlebar connection portions of the first stem and the second stem are configured so that they are located forward of the steering column, and are configured so that when the same torque is input around the X-axis, the torque sensor is less likely to deform than the torque sensor.

2. A bicycle stem as claimed in claim 1, wherein the X-axis extends in the left-right, up-down or front-to-back direction.

3. A bicycle stem according to claim 1, wherein the first stem is spaced apart from the second stem in the X-axis direction.

4. A bicycle stem as described in claim 1, further comprising an X-axis direction movement restriction portion between the first stem and the second stem, which restricts relative movement of the first stem and the second stem in the X-axis direction to more than a predetermined amount.

5. A bicycle stem as described in claim 1, further comprising an X-axis rotation restricting portion between the first stem and the second stem, which restricts relative rotation of the first stem and the second stem about the X-axis by more than a predetermined angle.

6. A bicycle stem as described in claim 1, wherein the first stem and the second stem are configured so that, when viewed in the axial direction of the steering column, the handle connection portion, the first torque sensor connection portion, the second torque sensor connection portion, and the steering column connection portion are aligned in the fore-and-aft direction.

7. A bicycle stem according to claim 1, wherein the first torque sensor connection portion of the first stem or the second torque sensor connection portion of the second stem is connected to a case of the torque sensor.

8. A bicycle stem according to claim 1, wherein the first torque sensor connection portion of the first stem or the second torque sensor connection portion of the second stem is integrally formed with at least a portion of a case of the torque sensor.

9. A bicycle comprising a bicycle stem according to any one of claims 1 to 8.

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