Pedal-equipped bicycle

Abstract

Provided is a pedal-equipped bicycle capable of supporting a rider counteracting disturbances even during vehicle operation in a left-right direction due to the rider pushing on the left and right pedals. A control device 53 of a pedal-equipped bicycle 1 controls a steering assist actuator 52 such that, when a torque that causes a front wheel 21 to rotate clockwise around a rotation axis P with respect to a steering unit 33 when viewed in one direction in a rotation axis direction is detected by a torque detection unit 51, an assist torque TQ3 that rotates the front wheel 21 counterclockwise around the rotation axis P is generated in a steering column 31. Additionally, the control device 53 controls the steering assist actuator 52 such that, when a torque that causes the front wheel 21 to rotate counterclockwise around the rotation axis P with respect to the steering unit 33 when viewed in one direction in the rotation axis direction is detected by the torque detection unit 51, an assist torque TQ3 that rotates the front wheel 21 clockwise around the rotation axis P is generated in the steering column 31.

Description

Pedal bicycle

[0001] The present invention relates to pedal bicycles.

[0002] Pedal bicycles with electric motors that output assist force according to pedal force are known. For example, Patent Document 1 discloses an electrically assisted bicycle that can be set to a standing-pedaling mode. In the electrically assisted bicycle described in Patent Document 1, a standing-pedaling determination unit determines whether or not the bicycle is being stood-pedaled based on the output of a tilt angle sensor, etc. Furthermore, in the electrically assisted bicycle described in Patent Document 1, the standing-pedaling mode is set if it is determined that the bicycle is being stood-pedaled. In the electrically assisted bicycle described in Patent Document 1, a target assist force is set so that a greater assist force is obtained in the standing-pedaling mode than in the normal riding mode.

[0003] As a result, the electrically assisted bicycle described in Patent Document 1 provides a more comfortable ride when the rider pedals the bicycle while leaning the body left and right.

[0004] Japanese Patent Application Publication No. 2018-001837

[0005] In order to move the pedal bicycle in a straight line by depressing the left and right pedals, the rider tilts the bicycle left and right in the opposite direction to the pedal that is depressed. In other words, the rider maintains the balance of the bicycle by tilting the bicycle left and right in accordance with the force of the pedals.

[0006] If the front wheel is disturbed by the road surface while the rider is maneuvering the vehicle body left or right in accordance with the pedal pressure applied by the rider, it may be difficult for the rider to maintain balance of the vehicle body. There is a need for a bicycle that can support the rider in responding to such disturbances even while the rider is maneuvering the vehicle body left or right in accordance with the pedal pressure applied by the rider.

[0007] The present invention aims to provide a pedal bicycle that can support the rider in responding to external disturbances even while the rider is operating the bicycle body left and right in accordance with the rider's depression of the left and right pedals.

[0008] The inventors have studied a configuration for a pedal bicycle that can support the rider in responding to external disturbances even while the rider is maneuvering the bicycle body left and right in accordance with the rider's depressing the left and right pedals.

[0009] Taking into consideration the relationship between pedaling and the left-right posture of the vehicle body as described above, the inventors came up with a pedal bicycle configuration that can support the rider in responding to external disturbances even while the rider is operating the vehicle body left-right in accordance with the rider's pressure on the left and right pedals.

[0010] As a result of the above-mentioned intensive investigations, the present inventors have come up with the following configuration.

[0011] A pedal-equipped bicycle according to one embodiment of the present invention comprises a body frame including a head tube, a steering column extending axially of the head tube and rotatably supported by the head tube, a fork section connected to a lower part of the steering column in the vertical direction of the body frame, a front wheel supported by the fork section, and a steering section connected to an upper part of the steering column in the vertical direction of the body frame and capable of steering the front wheel by rotating the steering column about the axis. The pedal-equipped bicycle also comprises a torque detection section between the steering section and the front wheel that detects torque applied to the steering column in a rotational direction about a rotation axis, a steering assist actuator that outputs torque to the steering column about the rotation axis, and a control device that controls the steering assist actuator based on the torque detection result by the torque detection section. When the torque detection unit detects a torque that causes the front wheels to rotate counterclockwise around the rotation axis when viewed in one direction of the rotation axis, the control device controls the steering assist actuator to output a torque that causes the steering column to rotate clockwise around the rotation axis based on the detected torque, and when the torque detection unit detects a torque that causes the front wheels to rotate clockwise around the rotation axis when viewed in one direction of the rotation axis, the control device controls the steering assist actuator to output a torque that causes the steering column to rotate counterclockwise around the rotation axis based on the detected torque.

[0012] The above-described configuration includes a torque detection unit that detects torque applied to the steering column between the steering unit and the front wheels. The roll angle or roll rate is a physical quantity that occurs after the occurrence of tilting of the vehicle body. In contrast, the torque that causes the front wheels to rotate around the rotation axis of the steering column relative to the steering unit occurs when a disturbance from the road surface is applied to the front wheels, and therefore can be detected more quickly than the roll angle or roll rate, which are physical quantities that occur after the occurrence of tilting.

[0013] Therefore, the control device controls the steering assist actuator to output torque based on the torque detection result by the torque detection unit. With this configuration, it is possible to start control of the steering assist actuator before the vehicle body tilts or at the early stage of the vehicle body tilt. Therefore, it is possible to control the steering assist actuator based on the torque generated by the application of an external force to the front wheels so that the vehicle body does not tilt or so that the vehicle body returns to its original posture at an early stage.

[0014] Furthermore, when the torque detection unit detects a torque that causes the front wheels to rotate counterclockwise relative to the steering unit around the rotation axis as viewed in one direction of the rotation axis, the control device controls the steering assist actuator to output to the steering column a torque that causes the steering column to rotate clockwise around the rotation axis as viewed in one direction of the rotation axis. Furthermore, when the torque detection unit detects a torque that causes the front wheels to rotate clockwise relative to the steering unit around the rotation axis as viewed in one direction of the rotation axis, the control device controls the steering assist actuator to output to the steering column a torque that causes the steering column to rotate counterclockwise around the rotation axis as viewed in one direction of the rotation axis.

[0015] Furthermore, while the driver is operating the vehicle body in the left and right directions in accordance with his / her depression of the left and right pedals, the driver performs an operation to tilt the vehicle body in the left and right directions but does not perform an operation to rotate the steering unit. Therefore, the control device controls the steering assist actuator so as not to output torque to the steering column while the driver is operating the vehicle body in the left and right directions.

[0016] For example, when a torque that rotates the front wheels is generated because the front wheels enter a rut or come into contact with a bump in the road surface while the driver is maneuvering the vehicle body in the left and right direction in accordance with the depression of the left and right pedals, the control device controls the steering assist actuator to output a torque to the steering column that cancels the rotation of the front wheels. Thus, the control device can support the driver in responding to the disturbance even while the driver is maneuvering the vehicle body in the left and right direction in accordance with the depression of the left and right pedals.

[0017] From another perspective, the pedal-equipped bicycle of the present invention preferably includes the following configuration: When the torque detection unit detects torque that causes the steering section to rotate counterclockwise around the rotation axis as viewed in one direction of the rotation axis, the control device controls the steering assist actuator to generate torque that causes the steering column to rotate counterclockwise around the rotation axis based on the detected torque, and when the torque detection unit detects torque that causes the steering section to rotate clockwise around the rotation axis as viewed in one direction of the rotation axis, the control device controls the steering assist actuator to generate torque that causes the steering column to rotate clockwise around the rotation axis based on the detected torque.

[0018] By controlling the control device in this manner, when a torque that rotates the front wheels is generated in the steering unit, the control device can stabilize steering by suppressing rotation in a direction unintended by the driver, and when a torque that attempts to rotate the steering unit relative to the front wheels around the rotation axis of the steering unit is detected, the control device can assist rotation in the direction intended by the driver. Thus, it is possible to support the driver in responding to disturbances even while the driver is operating the vehicle body in the left and right directions in accordance with the depression of the left and right pedals by the driver.

[0019] From another perspective, the pedal-equipped bicycle of the present invention preferably includes the following configuration: the fork section includes a left fork section supporting the left end of the front wheel axle, a right fork section supporting the right end of the front wheel axle, and a connecting section connecting the upper ends of the left fork section and the right fork section and connecting to the lower part of the steering column. The torque detection section is located between the steering section and the steering column and detects torque applied to the steering column in the direction of rotation about the rotation axis.

[0020] In the above-described configuration, the pine-needle fork, with the steering column connected to the upper ends of the left and right fork sections, rotates around the rotation axis of the steering column when the steering section is steered. In other words, an external force acting on the front wheels is detected by the torque detection section as torque centered on the rotation axis of the steering column. Therefore, the torque detection section can linearly detect the torque generated by the external force acting on the front wheels. Therefore, the system can support the driver in responding to external disturbances even while the driver is operating the vehicle left or right in accordance with the driver's depressing of the left and right pedals.

[0021] From another perspective, the pedal bicycle of the present invention preferably includes the following configuration: The control device is capable of changing the torque output by the steering assist actuator in response to the torque detected by the torque detection unit, or is capable of maintaining the torque output by the steering assist actuator at a constant value in response to the torque detected by the torque detection unit.

[0022] According to the above-described configuration, by changing the torque output by the steering assist actuator in response to the magnitude of the torque detected by the torque detection unit, control can be performed according to the size, structure, weight, type, use, etc. of the pedal bicycle. This allows for precise assistance suited to the size, structure, weight, type, use, etc. of the pedal bicycle. Alternatively, by maintaining the torque output by the steering assist actuator at a constant value when the torque detection unit detects torque, battery power consumption can be reduced and the time for which assistance is available can be extended. Therefore, the system can support the driver in responding to disturbances even while the vehicle is being steered left or right in accordance with the driver's depressing the left and right pedals.

[0023] From another perspective, the pedal-equipped bicycle of the present invention preferably includes the following configuration: The range in which the torque is applied to the steering column by the steering-assist actuator is a range of 180 degrees or less within the rotation range of the steering section about the rotation axis.

[0024] A bicycle has the characteristic that when it is moving, it turns corners mainly by leaning the body, whereas when it is being pushed, the direction of travel is determined by the steering angle of the steering unit.

[0025] According to the above-described configuration, the torque is applied to the steering column by the steering assist actuator within a 180-degree rotation range of the steering unit about the rotation axis. Therefore, even in a situation where the turning is mainly due to the steering of the steering unit rather than due to the leaning of the vehicle body, such as when the rider dismounts from the pedal bicycle and pushes the bicycle, the rider's response to disturbances can be assisted.

[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 meaning in the context of the relevant art and 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 pedal 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] [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.

[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 central portion of the handlebar.

[0039] [Forward / Backward Direction] In this specification, the forward / backward direction means the forward / backward direction of the vehicle as seen by a rider riding the bicycle.

[0040] [Left and right direction] In this specification, the left and right direction means the left and right direction of the vehicle as seen by a rider riding the bicycle.

[0041] According to one embodiment of the present invention, a pedal bicycle can be realized that can support the rider in responding to external disturbances even while the rider is operating the vehicle left and right in accordance with the rider's pressure on the left and right pedals.

[0042] FIG. 1 is a left side view showing the schematic configuration of a pedal bicycle. FIG. 2 is a front view of a pedal bicycle according to a first embodiment of the present invention with the left and right pedals not depressed. FIG. 3 is a front view of a pedal bicycle according to a first embodiment of the present invention with the left pedal depressed and tilted to the right. FIG. 4 is a front view of a pedal bicycle according to a first embodiment of the present invention with the right pedal depressed and tilted to the left. FIG. 5 is a flowchart illustrating steering assistance when entering a rut. FIG. 6 is a diagram showing the schematic configuration of a stem mechanism and a steering assist device of a pedal bicycle according to a first variation of the first embodiment of the present invention. FIG. 7 is a flowchart illustrating steering assistance in response to steering by the rider. FIG. 8 is a flowchart illustrating the steering range. FIG. 9 is a schematic diagram illustrating steering assistance by a pedal bicycle.

[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, the arrow FR in the figures indicates the forward direction of the vehicle. The arrow RR in the figures indicates the rearward direction of the vehicle. The arrow UP in the figures indicates the upward direction of the vehicle. The arrow DN in the figures indicates the downward direction of the vehicle. The arrow LF in the figures indicates the leftward direction of the vehicle. The arrow RG 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 of the pedal bicycle.

[0045] (Embodiment 1) Fig. 1 is a left side view showing the schematic configuration of a pedaled bicycle 1 according to embodiment 1. Fig. 9 is a schematic diagram illustrating steering assistance provided by the pedaled bicycle 1. The pedaled bicycle 1 according to this embodiment is, for example, a two-wheeled vehicle. The pedaled bicycle 1 has a front wheel 21, a rear wheel 22, a body frame 10 including a head tube 11, a steering column 31, a fork section 32, a steering section 33, left and right pedals 41, and a steering assist device 50. The configurations of the front wheel 21, the rear wheel 22, the body frame 10, and the left and right pedals 41 are similar to those of conventional bicycles, and therefore detailed description thereof will be omitted.

[0046] The steering column 31 is rotatably supported by the head tube 11 located at the front of the body frame 10. The steering column 31 extends along the axis of the head tube 11. The steering column 31 rotates around the rotation axis P, with the axis serving as the rotation axis P. The steering column 31 passes through the head tube 11 of the body frame 10. The steering column 31 extends obliquely so that the upper end is located rearward of the lower end.

[0047] The fork portion 32 rotatably supports the front wheel 21 at its lower end. The fork portion 32 is connected to the lower part of the steering column 31 in the vertical direction of the vehicle body. That is, the steering column 31 is connected to the upper end of the fork portion 32. The steering column 31 and the fork portion 32 form a so-called pine-needle fork. The fork portion 32 has a left fork portion 321, a right fork portion 322, and a connecting portion 323.

[0048] The left fork portion 321 supports the left portion of the axle of the front wheel 21. The right fork portion 322 supports the right portion of the axle of the front wheel 21. The connecting portion 323 connects the upper end of the left fork portion 321 and the upper end of the right fork portion 322, and is connected to the lower portion of the steering column 31.

[0049] The steering section 33 has a stem mechanism 331 and a handle 332. The stem mechanism 331 is attached to the upper end of the steering column 31. The handle 332 is supported on the steering column 31 by the stem mechanism 331.

[0050] The steering unit 33 is connected to the upper part of the steering column 31 in the vertical direction of the vehicle body, and is capable of steering the front wheels 21 by rotating the steering column 31 about the rotation axis P.

[0051] The steering assist device 50 assists in steering the steering wheel 332 based on the torque input to the steering wheel 332 or the steering column 31. The steering assist device 50 has a torque detection unit 51, a steering assist actuator 52, and a control device 53.

[0052] The torque detection unit 51 detects the torque about the rotation axis P between the steering unit 33 and the front wheels 21. More specifically, the torque detection unit 51 includes a torque sensor that detects the torque between the steering unit 33 and the steering column 31.

[0053] In the above-described configuration, the rotating parts that rotate around the rotation axis P when steered by the steering unit 33 are the various parts of the fork unit 32. In other words, these rotating parts are the parts below the steering column 31. Meanwhile, the torque detection unit 51 detects the torque between the steering unit 33 and the steering column 31. This makes it easier to lay out the torque detection unit 51 in a way that avoids the rotating parts of the pedal-equipped bicycle 1. This improves the degree of freedom in arranging the torque detection unit 51.

[0054] The steering assist actuator 52 outputs torque centered on the rotation axis P to the steering column 31. In addition, torque centered on the rotation axis P is input to the steering assist actuator 52 from the steering column 31.

[0055] The control device 53 controls the steering assist actuator 52 based on the torque detection result by the torque detection unit 51. That is, the control device 53 controls the steering assist actuator 52 based on the output of the torque sensor, not the output of the roll angle sensor or the roll rate sensor.

[0056] The external force acting on the front wheels 21 is detected by the torque detection unit 51 as a torque centered on the rotation axis P of the steering column 31. Therefore, the torque detection unit 51 can linearly detect the torque generated by the external force on the front wheels 21. Therefore, it is possible to support the driver in responding to disturbances even while the driver is operating the vehicle body in the left and right directions in accordance with the depression of the left and right pedals 41 by the driver.

[0057] (Regarding behavior of the bicycle body when pedaling) Using Figures 2 to 4, we will explain how the rider operates the pedaled bicycle 1 when they depress the left pedal 411 and right pedal 412, which are the left and right pedals 41. Figure 2 is a front view of the pedaled bicycle 1 with the left pedal 411 and right pedal 412 not depressed. Figure 3 is a front view of the pedaled bicycle 1 in a state where the left pedal 411 is depressed and the bicycle is tilted to the right. Figure 4 is a front view of the pedaled bicycle 1 in a state where the right pedal 412 is depressed and the bicycle is tilted to the left.

[0058] As shown in Figures 2 and 3, when a rider of a pedaled bicycle 1 positioned in the neutral position N, for example, depresses the left pedal 411 (see arrow A1), he or she pulls the left part of the handlebar 332 upward with his or her left hand (see arrow A2) to absorb the upward reaction force generated by depressing the left pedal 411 and to prevent the center of gravity of the pedaled bicycle 1 from moving from the left-right center line CL of the vehicle body.

[0059] When the rider pulls the left part of the handlebar 332 upward in accordance with the magnitude of the pedaling force on the left pedal 411, the pedaled bicycle 1 is tilted to the right of the neutral position N around the contact point G of the front wheel 21 and rear wheel 22 with the road surface as the center of rotation. At this time, the rider adjusts their body posture so that their center of gravity is aligned with the center line CL when viewed from above. As a result, the center of gravity of the pedaled bicycle 1, including the rider, is maintained near the center line CL when viewed from above by the force applied to the left pedal 411 and the tilt of the pedaled bicycle 1 to the right.

[0060] When the driver moves the left pedal 411 to the lowest position, he or she finishes lifting up the left part of the handlebars 332. Furthermore, the driver depresses the right pedal 412 and pulls up the right part of the handlebars 332 in accordance with the pedaling force on the right pedal 412.

[0061] The pedaled bicycle 1, which has been tilted to the right of the neutral position N, is tilted toward the neutral position N from a position tilted to the right of the neutral position N with the ground contact position G of the front wheel 21 and the rear wheel 22 as the center of rotation by the rider pulling up the left part of the handle 332 according to the magnitude of the pedaling force on the right pedal 412.

[0062] As shown in Figure 4, the pedaled bicycle 1 is tilted to the left of the neutral position N by the rider depressing the right pedal 412 (see arrow A3) and pulling up the right portion of the handlebars 332 (see arrow A4). At this time, the rider adjusts their body posture so that their center of gravity is aligned with the center line CL when viewed from above. As a result, the center of gravity of the pedaled bicycle 1, including the rider, is maintained near the center line CL when viewed from above due to the rider's depressing the right pedal 412 and the leftward tilt of the pedaled bicycle 1.

[0063] To maintain the center of gravity of the pedaled bicycle 1, including the rider, near the center line CL, the rider tilts the pedaled bicycle 1 to the right in response to the pedaling of the left pedal 411 and to the left in response to the pedaling of the right pedal 412. When the rider stands up from the saddle 7 and depresses the left and right pedals 411, 412 (dancing) in order to transmit greater driving force to the rear wheel 22, the tilt of the pedaled bicycle 1 caused by pulling up the handlebars 332 in response to the pedaling force on the left and right pedals 411, 412 is greater than the tilt when the rider is seated in the saddle 7. In this way, the pedaled bicycle 1 moves straight without turning by alternately tilting left and right in response to the pedaling of the left and right pedals 411, 412.

[0064] While the driver is operating the vehicle body in the left and right directions in accordance with the depression of the left and right pedals 41, the driver performs an operation to tilt the vehicle body in the left and right directions, but does not perform an operation to rotate the steering unit 33. Therefore, the steering assist actuator 52 does not output torque to the steering column while the driver is operating the vehicle body in the left and right directions.

[0065] (Steering assist when entering a rut) With reference to Figures 5 and 9, steering assist when the front wheel 21 of the pedal bicycle 1 enters a rut while the rider is operating the vehicle body left and right in accordance with the rider's depression of the left and right pedals 41 will be described. Figure 5 is a diagram illustrating steering assist when entering a rut R1. Figure 9 is a schematic diagram illustrating steering assist by the pedal bicycle 1. The steering angle is the turning angle of the front wheel 21 with respect to the center line CL of the vehicle in the left-right direction. The left side wall portion R11 of the rut R1 extends in a direction that intersects with the forward direction of the vehicle.

[0066] 5 and 9, in step S11, with the steering angle of the front wheel 21 at zero, the pedal bicycle 1 enters the rut R1 while tilting alternately left and right in accordance with the pressure on the left and right pedals 41. At this time, the steering assist actuator 52 is not outputting torque to the steering column.

[0067] Next, in step S12, the front wheel 21 comes into contact with the left side wall portion R11 of the wheel rut R1. This generates a disturbance torque TQ1 that tends to rotate the front wheel 21 clockwise around the rotation axis P. Because the driver D1 is gripping the handlebars 332 of the steering unit 33 with his or her hands, the disturbance torque TQ1 applied to the front wheel 21 is transmitted to the upper arm of the driver D1 via the fork portion 32, the steering column 31, and the steering unit 33 (see FIG. 1 ). In response to this, a counter torque TQ2 is generated due to the inertia of the upper arm of the driver D1, which counteracts the movement of the front wheel 21 that tends to rotate clockwise around the rotation axis P. In other words, a counter torque TQ2 that rotates counterclockwise around the rotation axis P is generated against the disturbance torque TQ1. The torque detection unit 51 detects the counter torque TQ2.

[0068] Next, in step S13, the control device 53 controls the steering assist actuator 52 based on the detection result of the counter torque TQ2 by the torque detection unit 51. Specifically, the control device 53 controls the steering assist actuator 52 to output an assist torque TQ3 in the counterclockwise direction about the rotation axis P, for example, so that the counter torque TQ2 becomes zero. Note that the assist torque TQ3 may be larger or smaller than the counter torque TQ2.

[0069] Because the front wheel 21 can maintain traction with the ground, the pedal bicycle 1 can climb over the left wall portion R11 of the rut R1, allowing the pedal bicycle 1 to continue traveling forward.

[0070] As described above, when the torque detection unit 51 detects a torque that causes the front wheels 21 to rotate clockwise about the rotation axis P relative to the steering unit 33 as viewed in one direction of the rotation axis, the control device 53 controls the steering assist actuator 52 so that an assist torque TQ3 that causes the steering column 31 to rotate counterclockwise about the rotation axis P is generated in the steering column 31. The same is true vice versa. In other words, when the torque detection unit 51 detects a torque that causes the front wheels 21 to rotate counterclockwise about the rotation axis P relative to the steering unit 33 as viewed in one direction of the rotation axis, the control device 53 controls the steering assist actuator 52 so that an assist torque TQ3 that causes the steering column 31 to rotate clockwise about the rotation axis P is generated in the steering column 31.

[0071] The control device 53 controls the steering assist device 50 to output an assist torque TQ3 corresponding to the force with which the driver holds the steering wheel 332 when the front wheel 21 comes into contact with the left wall portion R11 of the rut R1, thereby suppressing an increase in the steering angle of the front wheel 21. In other words, it is possible to suppress a deviation between the yaw angle of the body frame 10 and the steering angle of the front wheel 21. This prevents the front wheel 21 from getting caught in the rut R1 and causing the vehicle body to roll inadvertently. Therefore, it is possible to support the driver D1 in responding to disturbances even while the driver D1 is operating the vehicle body in the left / right direction in accordance with his / her depression of the left and right pedals 41.

[0072] In the above-described configuration, the torque that causes the front wheels 21 to rotate relative to the steering unit 33 around the rotation axis P of the steering column 31 is generated at the moment an external force from the road surface is applied to the front wheels 21, and therefore can be detected more quickly than the roll angle or roll rate, which are physical quantities that are detected after the fact.

[0073] Therefore, the control device 53 controls the steering of the steering assist actuator 52 based on the torque detection result by the torque detection unit 51. With this configuration, the steering control of the steering assist actuator 52 can be executed in response to the torque detection, even without detecting the tilt of the vehicle body. Therefore, with the above configuration, more preliminary measures can be taken in response to the torque detection. Therefore, it is possible to respond, for example, to an early stage of a disturbance.

[0074] Furthermore, while the driver D1 is operating the vehicle body in the left-right direction in accordance with the depression of the left and right pedals 41, the driver D1 performs an operation to tilt the vehicle body in the left-right direction, but does not perform an operation to rotate the steering unit 33 around the rotation axis P. Therefore, if torque of the front wheels 21 is detected during the vehicle body operation in the left-right direction, it is highly likely that the torque is due to a disturbance not intended by the driver D1.

[0075] By performing the control described above, if, for example, the front wheel 21 enters a rut or a bump in the road while driving, and a torque that causes the front wheel 21 to rotate is generated due to an external disturbance rather than the intention of the driver D1, the control device 53 can apply a torque to the front wheel 21 via the steering assist actuator 52 to cancel the rotation of the front wheel 21.

[0076] (Variation 1 of Embodiment 1) A pedaled bicycle 1A according to Variation 1 of Embodiment 1 of the present invention will be described with reference to Figure 6. Figure 6 is a diagram showing the schematic configuration of the stem mechanism 331 and steering assist device 50 of the pedaled bicycle 1A according to Variation 1 of Embodiment 1 of the present invention. Note that in the following description of Variation 1, parts that are common to the pedaled bicycle 1 according to Embodiment 1 are given the same reference numerals and detailed description will not be repeated.

[0077] As shown in FIG. 6 , the stem mechanism 331 includes the bicycle stem 100 , an anchor 75 , and a top cap 76 .

[0078] The handle holding portion 110 has a handle connecting portion (not shown) at one end thereof, to which the handle 332 is connected. The other end of the handle holding portion 110 is connected to the torque detection portion 51.

[0079] The steering column holding portion 120 has, at one end, a steering column connection portion 121. The steering column 31 is connected to the steering column connection portion 121. The other end of the steering column holding portion 120 is connected to the torque detection portion 51.

[0080] The steering assist actuator 52 has a steering assist motor 521 and a torque transmission mechanism 522 .

[0081] The steering assist motor 521 is a motor that outputs torque around the motor rotation axis Q.

[0082] The torque transmission mechanism 522 transmits the output of the steering assist motor 521 to the steering column 31. For example, the torque transmission mechanism 522 transmits the output of the steering assist motor 521 to the steering column 31, or transmits the torque from the steering column 31 to the steering assist motor 521. The torque transmission mechanism 522 may be configured in any way, such as a gear, a link, a belt, or a chain, as long as it is capable of transmitting the torque of the steering assist motor 521 to the steering column 31. Furthermore, the torque transmission mechanism 522 may be configured to constantly transmit the output of the steering assist motor 521 to the steering column 31.

[0083] The steering assist motor 521 is located in front of the steering column 31. Although not specifically shown, the steering assist motor 521 is supported by the body frame 10 of the pedal bicycle 1A via a torque transmission mechanism 522.

[0084] The steering assist motor 521 may be located anywhere relative to the steering column 31, as long as it is located near the steering column 31, such as behind, to the left, or to the right of the steering column 31. Although not specifically shown, the steering assist motor 521 may be fixed to the head tube 11 by a detent that restricts rotation about the rotation axis P relative to the head tube 11 of the pedal-equipped bicycle 1A.

[0085] (Variation 2 of Embodiment 1) A pedaled bicycle 1B according to Variation 2 of Embodiment 1 of the present invention will be described with reference to Figure 7. Figure 7 is a flow chart illustrating steering assistance in response to steering by rider D1. Note that in the following description of Variation 2, parts that are common to the pedaled bicycle 1 according to Embodiment 1 are given the same reference numerals and detailed description will not be repeated.

[0086] 7, in step S21, with the steering angle of the front wheel 21 at zero, the pedaled bicycle 1B enters the rut R1 while tilting alternately left and right in accordance with the rider's depression of the left and right pedals 41. At this time, the steering assist actuator 52 does not output torque to the steering column.

[0087] In step S22, the driver D1 steers the steering wheel 332 to attempt to rotate the steering column 31 counterclockwise around the rotation axis P. This generates a torque TQ21 that tends to rotate the front wheels 21 counterclockwise around the rotation axis P. In response to this, a counter torque TQ22 that opposes the movement of the front wheels 21 to rotate counterclockwise around the rotation axis P is generated in the front wheels 21 due to frictional force with the ground. The torque detection unit 51 detects the torque TQ21 that tends to rotate the front wheels 21 counterclockwise around the rotation axis P.

[0088] Next, in step S23, the control device 53 controls the steering assist actuator 52 based on the detection result of the torque TQ21 by the torque detection unit 51. Specifically, the control device 53 controls the steering assist actuator 52 so that the steering assist actuator 52 outputs an assist torque TQ23 that tends to rotate the front wheels 21 counterclockwise about the rotation axis P.

[0089] As described above, when the torque detection unit 51 detects a torque that causes the steering unit 33 to rotate counterclockwise relative to the front wheels 21 around the rotation axis P as viewed in one direction of the rotation axis P, the control device 53 controls the steering assist actuator 52 to output a counterclockwise torque to the steering column 31 around the rotation axis P based on the detected torque. Also, when the torque detection unit 51 detects a torque that causes the steering unit 33 to rotate clockwise relative to the front wheels 21 around the rotation axis P as viewed in one direction of the rotation axis P, the control device 53 controls the steering assist actuator 52 to generate a clockwise torque to the steering column 31 around the rotation axis P based on the detected torque.

[0090] By such control by the control device 53, when torque by the steering unit 33 is detected, it is possible to assist the driver D1 in the direction intended by the driver D1.

[0091] The control device 53 may be configured to be able to change the value of the torque output by the steering assist actuator 52 in response to the magnitude of the torque detected by the torque detection unit 51. Such a control device 53 can perform control according to the size, structure, weight, type, use, etc. of the pedaled bicycle 1B by changing the torque output by the steering assist actuator in response to the magnitude of the torque detected by the torque detection unit 51. This can support the rider in responding to disturbances even while the rider is maneuvering the bicycle body in the left-right direction in accordance with the rider's depression of the left and right pedals.

[0092] Furthermore, the control device 53 may be configured to maintain the torque output by the steering assist actuator 52 at a constant value relative to the magnitude of the torque detected by the torque detection unit 51. This reduces the amount of power consumed by the battery that drives the steering assist actuator 52 and extends the time for which assistance is possible. Therefore, it is possible to support the driver in responding to disturbances even while the driver is operating the vehicle body in the left and right directions in accordance with the driver's depression of the left and right pedals.

[0093] (Variation 3 of Embodiment 1) A pedaled bicycle 1C according to Variation 3 of Embodiment 1 of the present invention will be described with reference to Figure 8. Figure 8 is a diagram illustrating the steering range. Note that in the following description of Variation 1, parts that are common to the pedaled bicycle 1 according to Embodiment 1 are given the same reference numerals and detailed description will not be repeated.

[0094] As shown in FIG. 8, the range in which torque is applied to the steering column 31 by the steering assist actuator 52 is a range of 180 degrees or less within the rotation range of the steering section 33 about the rotation axis P.

[0095] In other words, the range in which torque is applied to the steering column 31 by the steering assist actuator 52 is from a state in which the steering angle of the front wheels 21 is zero to +90° counterclockwise around the rotation axis P, and from a state in which the steering angle of the front wheels 21 is zero to +90° clockwise around the rotation axis P.

[0096] When the rider D1 dismounts from the pedaled bicycle 1C and is pushing the pedaled bicycle 1C, the steering angle at which the steering unit 33 is rotated about the rotation axis P of the steering column 31 is larger than when the pedaled bicycle 1C is in a traveling state. This is due to the characteristics of the pedaled bicycle 1C in that, when the pedaled bicycle 1C is in a traveling state, turning is mainly due to the leaning of the body, whereas when the pedaled bicycle 1C is being pushed, the direction of travel is determined by the steering angle of the steering unit 33.

[0097] According to the above-described configuration, when pushing the pedal-equipped bicycle 1C, the steering assist actuator 52 applies the torque to the steering column 31 within a 180-degree rotation range centered on the rotation axis P of the steering section 33.

[0098] This allows the pedal bicycle 1C to respond to external disturbances such as ruts even when the steering unit 33 is rotated in a wide range of directions while being pushed along. Also, the pedal bicycle 1C can respond to external disturbances even when traveling at low speeds.

[0099] 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.

[0100] In each of the above-described embodiments, the pedal bicycles 1, 1A, 1B, and 1C assist the rider D1 in steering by using a steering assist device 50. However, the pedal bicycle may also have a pedaling force assist device that uses an electric motor or the like to assist the pedaling force.

[0101] In each of the above-described embodiments, the stem mechanism 331 is an ahead stem. However, the stem mechanism 331 may be a threaded stem that is connected to the steering column by pressing a fixing member provided at the lower end against the inner surface of the upper part of the steering column.

[0102] In each of the above-described embodiments, the pedal bicycles 1, 1A, 1B, and 1C have a pine-needle-shaped fork 32 in which the left fork 321 and the right fork 322 are connected by a single connecting part 323. However, the pedal bicycle may have a fork in which the left fork 321 and the right fork 322 are connected by multiple connecting parts.

[0103] In each of the above-described embodiments, the torque detection unit 51 detects the torque between the steering unit 33 and the steering column 31. However, the torque detection unit 51 may also detect the torque between the steering column and the fork unit.

[0104] In the first variation of the first embodiment, the torque detector 51 is located in the front-to-rear direction relative to the steering column connection portion 121. However, the torque detector may also be located in the left-to-right direction relative to the steering column connection portion. In this case, the torque detector may be located in a position where at least a portion of the torque detector overlaps with the steering column connection portion when viewed from the left to right of the bicycle stem. Furthermore, the torque detector may be located so that a portion of the torque detector overlaps with the steering column holder when viewed from the front-to-rear direction of the bicycle stem.

[0105] In each of the above-described embodiments, the torque detection unit 51 is located in front of the steering column 31. However, the torque detection unit may be located behind the steering column, or may be located to the left or right of the steering column.

[0106] In each of the above-described embodiments, the steering column 31 extends in an oblique direction. However, the steering column 31 may extend in a vertical direction.

[0107] DESCRIPTION OF SYMBOLS 1, 1A, 1B, 1C Pedaled bicycle 21 Front wheel 22 Rear wheel 10 Body frame 11 Head tube 31 Steering column 32 Fork section 321 Left fork section 322 Right fork section 323 Connecting section 33 Steering section 331 Stem mechanism 332 Handlebar 41 Left and right pedals 411 Left pedal 412 Right pedal 50 Steering assist device 51 Torque detection section 52 Steering assist actuator 521 Steering assist motor 522 Torque transmission mechanism 53 Control device 7 Saddle 75 Anchor 76 Top cap 100 Bicycle stem 110 Handle holder 120 Steering column holder 121 Steering column connection section P Rotation axis Q Rotation axis CL Center line N Neutral position A1 Arrow indicating pressing down on the left pedal A2 Arrow indicating lifting up the left part of the handlebars A3 Arrow indicating pressing down on the right pedal A4 Arrow indicating lifting up the right part of the handlebars

Claims

1. A pedal-equipped bicycle having: a body frame including a head tube; a steering column extending along the axial direction of the head tube and rotatably supported by the head tube; a fork section connected to a lower part of the steering column in the vertical direction of the body frame; a front wheel supported by the fork section; and a steering section connected to an upper part of the steering column in the vertical direction of the body frame and capable of steering the front wheel by rotating the steering column about the axis, wherein the pedal-equipped bicycle has a torque detection section between the steering section and the front wheel, the torque detection section detecting a torque applied to the steering column in a rotational direction about the rotation axis, a steering assist actuator outputting a torque about the rotation axis to the steering column, and a control device controlling the steering assist actuator based on a result of the torque detection by the torque detection section, wherein the control device A pedaled bicycle, wherein, when the torque detection unit detects a torque that causes the front wheel to rotate counterclockwise around the rotation axis when viewed in one direction of the rotation axis, the steering assist actuator is controlled to output a torque that rotates the steering column clockwise around the rotation axis based on the detected torque, and when the torque detection unit detects a torque that causes the front wheel to rotate clockwise around the rotation axis when viewed in one direction of the rotation axis, the steering assist actuator is controlled to output a torque that rotates the steering column counterclockwise around the rotation axis based on the detected torque.

2. A pedaled bicycle as described in claim 1, wherein the control device controls the steering assist actuator to generate a torque that rotates the steering column counterclockwise around the rotation axis based on the detected torque when the torque detection unit detects a torque that causes the steering section to rotate counterclockwise around the rotation axis when viewed in one direction of the rotation axis, and controls the steering assist actuator to generate a torque that rotates the steering column clockwise around the rotation axis based on the detected torque when the torque detection unit detects a torque that causes the steering section to rotate clockwise around the rotation axis when viewed in one direction of the rotation axis.

3. A pedaled bicycle as described in claim 1 or claim 2, wherein the fork section comprises a left fork section supporting the left portion of the front wheel axle, a right fork section supporting the right portion of the front wheel axle, and a connecting section connecting the upper end of the left fork section to the upper end of the right fork section and connecting to the lower part of the steering column, and the torque detection section is located between the steering section and the steering column and detects the torque applied to the steering column in the rotational direction around the rotation axis.

4. A pedaled bicycle as described in any one of claims 1 to 3, wherein the control device is capable of changing the torque output by the steering assist actuator in response to the torque detected by the torque detection unit, or is capable of maintaining the torque output by the steering assist actuator at a constant value in response to the torque detected by the torque detection unit.

5. A pedaled bicycle as described in any one of claims 1 to 4, wherein the range in which the torque is applied to the steering column by the steering assist actuator is a range of 180 degrees or less within the rotation range around the rotation axis of the steering section.

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