Pedal-equipped bicycle

Abstract

Provided is a pedal-equipped bicycle that is equipped with a steering assist device and that, while keeping operability during stand-up pedaling from being compromised, improves the responsiveness and control accuracy of the steering assist device. This pedal-equipped bicycle 1 includes: a body frame 2 including a head tube 21 and a down tube 22; a front fork 3; and a steering assist device 40 including a battery 41, a steering assist motor 42, a torque-transmitting mechanism 43, and a first power-source harness member 45. The steering assist device 40: (1) is arranged, viewing the pedal-equipped bicycle 1 in the left-right direction, so as to be frontward of the midpoint M of a line segment joining a front wheel axle 5a and a rear wheel axle 6a and frontward of the rotational center of a left crank 8 and a right crank 9, of the pedal-equipped bicycle 1; and (2) is arranged so that, viewing the pedal-equipped bicycle 1 in the up-down direction, the battery 41 and the steering assist motor 42 at least partially overlap the down tube 22.

Description

Pedal bicycle

[0001] The present invention relates to a pedal bicycle.

[0002] Pedal bicycles with electric power steering systems (EPS) that use electric actuators to assist the rider in steering are known. The electric power steering system includes a steering assist device that transmits torque to the steering column of the pedal bicycle using an electric steering assist motor, various sensors that detect the steering torque and steering angular velocity applied to the steering column, and a control device that controls the steering assist motor. The control device controls the steering assist motor based on the detected values ​​of the various sensors.

[0003] The steering assist motor is disposed on the pedal bicycle while being mechanically connected to the steering column by a gear, etc. The electrically assisted pedal bicycle described in Patent Document 1 includes a steering assist device that applies an assist force to the steering column, an assist motor that applies an assist force to the rear wheel, a battery that supplies power to the steering assist device and the assist motor, a first power harness member that electrically connects the steering assist device to the battery, and a second power harness member that electrically connects the assist motor to the battery.

[0004] International Publication No. 2017 / 057515

[0005] Pedal bicycles are designed to transmit torque to the rear wheel, which serves as the drive wheel, by alternately depressing the left and right pedals located on the left and right sides of the frame. When a rider depresses the left pedal, a downward force is applied to the left of an imaginary center line (hereinafter referred to as the "imaginary center line") in the lateral direction of the bicycle, which is not tilted laterally, as viewed from the front to rear. This shifts the center of gravity of the bicycle, including the rider, to the left of the imaginary center line.

[0006] At this time, the rider pulls up on the left handlebar with his or her left hand to absorb the upward reaction force generated by depressing the left pedal downward and maintain the vehicle's direction of travel. The rider's pulling up on the left handlebar causes the pedal bicycle to lean to the right. As a result, the combined center of gravity of the pedal bicycle, including the rider, which had moved leftward from the imaginary center line due to depressing the left pedal, moves toward the imaginary center line.

[0007] Next, the driver moves the left pedal to its lowest position, and when he finishes pulling up the left steering wheel, he depresses the right pedal and pulls up the right steering wheel. The vehicle, which was leaning to the right, returns from its rightward tilted position to a position where it is not tilted to the left or right (hereinafter referred to as the "neutral position") as a result of the driver pulling up the right steering wheel. When the vehicle returns to the neutral position, the driver begins to press down the right pedal in the same way as he pressed down the left pedal.

[0008] When the rider of the pedaled bicycle depresses the left and right pedals with greater force, the rider performs a "dancing" maneuver, in which the rider stands up from the saddle and depresses the left and right pedals. The tilt of the pedaled bicycle during "dancing" increases due to the increased pedaling force on the left and right pedals compared to the tilt of the bicycle when the rider depresses the left and right pedals while seated in the saddle. In this way, the rider maintains the balance and direction of travel of the pedaled bicycle by leaning the bicycle left or right based on the magnitude of the pedaling force on the left and right pedals. Therefore, the more even the weight balance between the left and right sides of the pedaled bicycle is, the easier it is to maneuver during "dancing."

[0009] In addition, a steering assist device assists steering by transmitting torque from a drive device such as a motor to a steering column that supports the front wheels. Torque transmission by the steering assist device depends on the frictional force between the front wheels and the road surface. In other words, the load on the front wheels must be taken into consideration when transmitting torque from the steering assist device.

[0010] The battery and the second power harness member of the steering assist device of the electrically assisted bicycle described in the cited document 1 are disposed behind the seat post. In the electrically assisted bicycle, the weight of the battery and the second power harness member is greater on the rear axle than on the front axle. In the electrically assisted bicycle, the load on the front wheel tends to be smaller than the load on the rear wheel. In other words, in the electrically assisted bicycle, the friction generated between the front wheel and the road surface tends to be smaller than the friction generated between the rear wheel and the road surface.

[0011] Furthermore, in the electrically assisted bicycle described in the aforementioned Patent Document 1, the motor for the steering assist device is disposed in front of the head tube. As a result, the moment of inertia about the yaw axis of the electrically assisted bicycle is increased. Therefore, in the electrically assisted bicycle, the greater the moment of inertia about the yaw axis, the less effective the steering assist device becomes. Therefore, there is a demand for a pedal-equipped bicycle that improves the responsiveness and control accuracy of the steering assist device while suppressing a decrease in operability during standing.

[0012] The present invention aims to provide a pedal bicycle equipped with a steering assist device that improves the responsiveness and control accuracy of the steering assist device while suppressing a decrease in operability when dancing.

[0013] The inventors have studied pedal bicycles equipped with a steering assist device that improves the responsiveness and control accuracy of the steering assist device while suppressing a decrease in operability during standing. After extensive research, the inventors have come up with the following configuration. The technical concept is to consolidate the steering assist motor, battery, first power harness member, and torque transmission mechanism that make up the steering assist device, which are heavy objects, to increase the front wheel load, thereby improving the responsiveness and control accuracy of the steering assist device while suppressing a decrease in operability during standing.

[0014] The pedal bicycle has a body frame including a head tube and a down tube whose front end is connected to the rear edge of the head tube and extends diagonally so that its rear end is located lower than the front end; a front wheel supported by a front fork including a steering column rotatably supported on the head tube; a rear wheel supported by the body frame; a left crank and a right crank supported on the body frame; and a steering assist device including a steering assist motor, a battery that supplies power to the steering assist motor, a first power harness member that electrically connects the steering assist motor and the battery, and a torque transmission mechanism that transmits the torque of the steering assist motor to the steering column.

[0015] The steering assist motor, the battery, the first power harness member, and the torque transmission mechanism are (1) positioned in their entirety forward of the midpoint of the line connecting the front wheel axle and the rear wheel axle of the pedal bicycle and the centers of rotation of the left crank and the right crank when viewed from the left to right of the pedal bicycle, and (2) positioned so that at least a portion of them overlaps with the down tube when viewed from the top to bottom of the pedal bicycle.

[0016] As described above, the steering assist motor, the battery, the first power harness member, and the torque transmission mechanism are (1) positioned in their entirety forward of the midpoint of the line connecting the front wheel axle and the rear wheel axle of the pedal bicycle and the centers of rotation of the left crank and the right crank when viewed from the left to right of the pedal bicycle. Therefore, the steering assist motor, the battery, the first power harness member, and the torque transmission mechanism are not positioned in their entirety rearward of the midpoint of the line connecting the front wheel axle and the rear wheel axle and the centers of rotation of the left crank and the right crank.

[0017] Furthermore, (2) the steering assist motor, the battery, the first power harness member, and the torque transmission mechanism are arranged so that at least a portion of them overlaps the down tube when the pedal-equipped bicycle is viewed from above. Therefore, the entire steering assist motor, the battery, the first power harness member, and the torque transmission mechanism are not located forward of the head tube. Alternatively, even if a portion of the steering assist motor, the battery, the first power harness member, and the torque transmission mechanism is located forward of the head tube, at least a portion of them is arranged so as to overlap the down tube, thereby reducing the amount of forward protrusion of the head tube.

[0018] The components of the steering assist device, including the steering assist motor, the battery, the first power harness member, and the torque transmission mechanism, are concentrated behind the head tube and forward of the midpoint of a line connecting the front axle and the rear axle of the pedal bicycle, and the centers of rotation of the left and right cranks. Therefore, in the pedal bicycle, the proportion of the weight of the steering assist device applied to the front axle is greater than the proportion of the weight of the steering assist device applied to the front axle in the electrically assisted bicycle described in Patent Document 1, in which the components of the steering assist device are dispersed. In other words, in the pedal bicycle, the proportion of the frictional force generated between the front and rear wheels and the road surface due to the weight of the steering assist device that is generated between the front wheel and the road surface is greater than the proportion of the frictional force generated between the front wheel and the road surface due to the weight of the steering assist device in the electrically assisted bicycle described in Patent Document 1. Therefore, the weight of the steering assist device is utilized to increase the frictional force generated between the front wheels and the road surface, which allows the torque of the steering assist motor to be transmitted more directly to the road surface, thereby improving the control accuracy of the steering assist device.

[0019] Furthermore, since the load applied to the front wheel increases and the components of the steering assist device, including the steering assist motor, the battery, the first power harness member, and the torque transmission mechanism, are located rearward of the head tube, or, even if they have a portion located forward of the head tube, their protrusion amount can be reduced, an increase in the moment of inertia about the yaw axis of the pedal-equipped bicycle is suppressed, thereby increasing the frictional force generated on the front wheel and improving the responsiveness of the turning control of the steering assist device.

[0020] In addition, the offset of the steering assist device relative to an imaginary center plane passing through the lateral centerline of the pedaled bicycle is suppressed. In other words, the left-right weight balance of the pedaled bicycle is less likely to be unbalanced. This reduces the effect of the steering assist device on the operation of leaning the pedaled bicycle left and right (dancing), and ensures freedom of leg movement for the rider positioned on both the left and right sides of the steering assist device. As a result, by concentrating the steering assist motor, the battery, the first power harness member, and the torque transmission mechanism and increasing the front wheel load, it is possible to improve the responsiveness and control accuracy of the steering assist device while suppressing a decrease in operability during dancing.

[0021] According to another aspect, the pedaled bicycle of the present invention may include the following configuration: When viewed from above, the steering assist motor, the battery, the first power harness member, and the torque transmission mechanism are located between the right outer edge of the left pedal supported by the left crank and the left outer edge of the right pedal supported by the right crank.

[0022] As described above, the steering assist motor, the battery, the first power harness member, and the torque transmission mechanism are located between a pair of imaginary planes passing through the right outer edge of the left pedal and the left outer edge of the right pedal. In other words, the steering assist motor, the battery, the first power harness member, and the torque transmission mechanism are prevented from interfering with the rider's left leg, which is placed to the left of the right outer edge of the left pedal, and the rider's right leg, which is placed to the right of the left outer edge of the right pedal. This ensures freedom of leg movement for the rider in a pedal-equipped bicycle equipped with the steering assist device. Furthermore, because at least a portion of the steering assist motor, the battery, the first power harness member, and the torque transmission mechanism are positioned so as to overlap the down tube when viewed vertically, it is difficult for the weight balance to be unbalanced in the lateral direction. This prevents a decrease in operability when the rider leans left or right in response to depression of the left and right pedals.

[0023] According to another aspect, the pedaled bicycle of the present invention may include the following configuration: When the pedaled bicycle is viewed from above, the pedal is located between both ends of the crankshaft that connects the left crank and the right crank.

[0024] As described above, the steering assist motor, the battery, the first power harness member, and the torque transmission mechanism are located between a pair of imaginary planes that pass through both ends of the crankshaft. In other words, the steering assist motor, the battery, the first power harness member, and the torque transmission mechanism are located away from the rider's left leg, which is placed to the left of the right outer edge of the left pedal, and the rider's right leg, which is placed to the right of the left outer edge of the right pedal, in the direction of the down tube. This further ensures freedom of movement for the rider's legs in a pedal-equipped bicycle equipped with the steering assist device. This reduces a decrease in operability when the rider leans left or right in response to depression of the left pedal and the right pedal.

[0025] According to another aspect, the pedal-equipped bicycle of the present invention may include the following configuration: the steering assist motor, the battery, the first power harness member, and the torque transmission mechanism are located between the left and right outer edges of the down tube when viewing the pedal-equipped bicycle from above.

[0026] As described above, the steering assist motor, the battery, the first power harness member, and the torque transmission mechanism are located between a pair of imaginary planes that pass through the left and right outer edges of the down tube. Therefore, the steering assist motor, the battery, the first power harness member, and the torque transmission mechanism are located close to the axis of the down tube within the left-right width of the down tube. This further ensures freedom of movement for the rider's legs in a pedal bicycle equipped with the steering assist device. Furthermore, the placement of the steering assist motor, the battery, the first power harness member, and the torque transmission mechanism reduces imbalances in the left-right weight balance of the pedal bicycle. This reduces a decrease in maneuverability when leaning the pedal bicycle left or right in response to depression of the left and right pedals.

[0027] From another perspective, the pedal-equipped bicycle of the present invention may include the following configuration: When viewed from above, the steering assist motor, the battery, the first power harness member, and the torque transmission mechanism are located between the left outer edge of the left fork section and the right outer edge of the right fork section of the front fork that support the front wheel.

[0028] As described above, the steering assist motor, the battery, the first power harness member, and the torque transmission mechanism are located between a pair of imaginary planes that pass through the left and right outer edges of the front fork. In other words, the steering assist motor, the battery, the first power harness member, and the torque transmission mechanism are not located laterally outward of the front fork in a longitudinal view. Therefore, the front fork of the pedaled bicycle prevents contact between the steering assist motor, the battery, the first power harness member, and the torque transmission mechanism and obstacles approaching from the front of the pedaled bicycle. This also prevents imbalances in the left-right weight balance of the pedaled bicycle due to the placement of the steering assist motor, the battery, the first power harness member, and the torque transmission mechanism. This reduces deterioration in maneuverability when leaning the pedaled bicycle left or right in response to depression of the left and right pedals.

[0029] The terminology used in this specification is used for the purpose of defining particular embodiments only, and is not intended to limit the invention.

[0030] As used herein, "and / or" includes all combinations of one or more of the associated listed members.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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 not to be construed in an idealized or overly formal sense unless expressly defined herein.

[0035] 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.

[0036] 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.

[0037] In this specification, an embodiment of a pedal bicycle according to the present invention will be described.

[0038] 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.

[0039] 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.

[0040] [Pedal Bicycle] In this specification, a pedal bicycle refers to a lean-type vehicle in which a body frame is supported by a front wheel located in front of the body frame and a rear wheel (drive wheel) located behind the body frame. The pedal bicycle also has a left pedal and a right pedal that the rider uses to transmit torque to the drive wheels. The pedal bicycle is configured to transmit torque to the drive wheels when the rider alternately presses down on the left pedal located to the left of the body frame and the right pedal located to the right of the body frame. The pedal bicycle rotatably supports the front wheel, for example, with a pine-needle fork rotatably supported on the body frame.

[0041] [Head Tube] In this specification, a head tube is a portion of the body frame of a pedal-equipped bicycle that supports the front fork. The head tube is located at the front end of the body frame. The head tube is a pipe-shaped member made of iron, aluminum, carbon, or the like. A top tube extending rearward and a down tube extending rearward and downward are connected to the rear end of the head tube. In other words, the head tube connects the top tube and the down tube.

[0042] [Down Tube] In this specification, the down tube refers to the part of the body frame of a pedal-equipped bicycle that connects the head tube, which supports the front fork, to the bottom bracket hanger, which supports the rotation shafts of the left and right pedals. The down tube is a pipe-shaped member made of iron, aluminum, carbon, or the like. The down tube extends rearward and downward from the head tube. Therefore, the down tube extends diagonally so that the upper end is located behind the lower end.

[0043] [Steering column] In this specification, the term "steering column" refers to a component of a pedal bicycle that is rotatably housed within the head tube and connected to the fork that rotatably supports the front wheel. The steering column is connected to a steering column connector of a bicycle stem.

[0044] [Steering Assist Device] In this specification, the steering assist device refers to a unit that combines an electric steering assist motor constituting an electric steering system, a torque transmission mechanism that transmits the torque of the steering assist motor to a steering column, a battery that supplies power to the steering assist motor, and a first power harness member that electrically connects the steering assist motor and the battery. The steering assist motor transmits torque to the torque transmission mechanism based on force input from the driver or the road surface. The torque transmission mechanism amplifies and transmits the torque of the steering assist motor to the steering column, which is the torque transmission target. The steering assist device performs, for example, steering support for the driver of a two-wheeled vehicle, steering operation to make the vehicle body self-sustaining, etc. Note that the steering assist device may be configured to include, for example, a control device, an input device, an output device, etc. in addition to the steering assist motor, the torque transmission mechanism, the battery, and the first power harness member.

[0045] [First power harness member] In this specification, the term "first power harness member" refers only to the portion of the entire harness of the pedal bicycle that electrically connects the battery and the steering assist motor. In a pedal bicycle having a drive motor that applies auxiliary driving force to the rear wheel or front wheel, the portion that electrically connects the drive motor and the battery is referred to as the second power harness member and is not included in the first power harness member. Furthermore, signal lines that transmit control signals from the input device of the steering assist device to a control device, etc., and signal lines that transmit detection signals from a torque sensor to a control device, etc., are not included in the first power harness member.

[0046] [Forward / Backward Direction] In this specification, the forward / backward direction refers to the forward / backward direction as seen from the rider of the pedal bicycle with the steering assist device attached to the pedal bicycle.

[0047] [Left and right direction] In this specification, the left and right direction means the left and right direction as seen from the rider of the pedal bicycle with the steering assist device attached to the pedal bicycle.

[0048] [Up-down direction] In this specification, the up-down direction means the up-down direction as seen from the rider of the pedal bicycle with the steering assist device attached to the pedal bicycle.

[0049] [Torque transmission mechanism] In this specification, the term "torque transmission mechanism" refers to a mechanism that transmits torque input via an input member to an output member. The torque transmission mechanism may be configured to transmit the input torque while changing the magnitude, direction, etc. of the input torque. The torque transmission mechanism may be configured, for example, with gears, chains, belts, links, etc.

[0050] [Dancing] In this specification, "dancing" refers to one method of riding a pedaled bicycle. In dancing, the rider of the pedaled bicycle alternately depresses the left and right pedals while not seated in the saddle, and alternately leans the bicycle body left and right in response to the pressure on the left and right pedals. Dancing is used when a large torque is transmitted to the pedaled bicycle, such as when traveling uphill or accelerating. Note that dancing also includes the case where the rider, while seated in the saddle, alternately leans the bicycle body left and right in response to the pressure on the left and right pedals.

[0051] [Yaw Axis of a Pedaled Bicycle] In this specification, the yaw axis of a pedaled bicycle refers to an axis extending in the vertical direction that passes through the center of gravity of the pedaled bicycle. When a rider is riding the pedaled bicycle, the yaw axis of the pedaled bicycle refers to an axis extending in the vertical direction that passes through the combined center of gravity of the rider and the center of gravity of the pedaled bicycle.

[0052] [Left outer edge and right outer edge when viewed in the vertical direction] In this specification, the left outer edge when viewed in the vertical direction means the boundary located at the leftmost part when the structure is viewed in the vertical direction, and the right outer edge when viewed in the vertical direction means the boundary located at the rightmost part when the structure is viewed in the vertical direction.

[0053] According to one embodiment of the present invention, it is possible to improve the responsiveness and control accuracy of the steering assist device while suppressing a decrease in operability during dancing.

[0054] FIG. 1 is a side view of a pedaled bicycle according to a first embodiment of the present invention. FIG. 2 is a top view of the pedaled bicycle according to the first embodiment of the present invention. FIG. 3 is a view taken along the arrows III-III in FIG. 1. FIG. 4 is a view taken along the arrows IV-IV in FIG. 1. FIG. 5 is a front view of the pedaled bicycle according to the first embodiment of the present invention with the left and right pedals not being depressed by the rider. FIG. 6 is a front view of the pedaled bicycle according to the first embodiment of the present invention with the left pedal tilted to the right when depressed by the rider. FIG. 7 is a front view of the pedaled bicycle according to the first embodiment of the present invention with the right pedal tilted to the left when depressed by the rider. FIG. 8 is a side view of a pedaled bicycle according to a modification of the first embodiment of the present invention.

[0055] Each embodiment will be described below with reference to the drawings. In each drawing, the same parts are given 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.

[0056] [Embodiment 1] <Overall configuration of pedaled bicycle> A pedaled bicycle 1 according to embodiment 1 of the present invention will be described using Figures 1 to 4. Figure 1 is a side view of the pedaled bicycle 1 according to embodiment 1 of the present invention. Figure 2 is a top view of the pedaled bicycle 1. Figure 3 is a view taken along the arrows III-III in Figure 1. Figure 4 is a view taken along the arrows IV-IV in Figure 1.

[0057] Hereinafter, arrow F in the figures indicates the forward direction of pedaled bicycle 1. Arrow RR in the figures indicates the rearward direction of pedaled bicycle 1. Arrow U in the figures indicates the upward direction of pedaled bicycle 1. Arrow D in the figures indicates the downward direction of pedaled bicycle 1. Arrow L in the figures indicates the leftward direction of pedaled bicycle 1. Arrow R in the figures indicates the rightward direction of pedaled bicycle 1. Furthermore, in the following description, the up-down, left-right, and front-to-rear directions respectively refer to the up-down, left-right, and front-to-rear directions as seen by the rider Br (see Figure 5) who is driving the pedaled bicycle 1.

[0058] As shown in Figures 1 and 2, a pedal bicycle 1 according to this embodiment has a steering assist device 40. The pedal bicycle 1 has a body frame 2, a front fork 3, a handlebar 4, a front wheel 5, a rear wheel 6, a saddle 7, a left crank 8, a right crank 9, and a crankshaft 10. The handlebar 4, the front wheel 5, the rear wheel 6, the saddle 7, the left crank 8, and the right crank 9 are configured in the same manner as in conventional bicycles, and detailed description thereof will be omitted. Components similar to those in the first embodiment will be assigned the same reference numerals and description thereof will be omitted.

[0059] The vehicle frame 2 supports a front fork 3, a rear wheel 6, a saddle 7, a left crank 8, and a right crank 9. The vehicle frame 2 includes a head tube 21, a down tube 22, a seat tube 23, a top tube 24, seat stays 25, and chain stays 26.

[0060] The head tube 21 supports the front fork 3. The head tube 21 is located at the front end of the body frame 2. The head tube 21 is disposed so as to extend in the vertical direction.

[0061] The down tube 22 connects the head tube 21 and the seat tube 23. The down tube 22 extends rearward and downward from the rear edge of the head tube 21. The rear end of the head tube 21 is positioned lower than the front end. The front end of the down tube 22 is connected to the lower end of the head tube 21. The rear end of the down tube 22 is connected to the lower end of the seat tube 23.

[0062] 3, when viewed in the axial direction, the width W1 of the down tube 22 in the left-right direction is greater than the width H of the down tube 22 in a direction perpendicular to the axial direction and the left-right direction. In other words, the cross section of the down tube 22 perpendicular to the axis is formed in a rectangular shape extending in the left-right direction.

[0063] 1, the seat tube 23 connects the down tube 22 and the top tube 24. The seat tube 23 supports the saddle 7.

[0064] The top tube 24 connects the seat tube 23 and the head tube 21. The top tube 24 extends forward and upward from the front edge of the upper end of the seat tube 23. The front end of the top tube 24 is positioned higher than the rear end. The rear end of the top tube 24 is connected to the upper end of the seat tube 23. The front end of the top tube 24 is connected to the upper end of the head tube 21.

[0065] The seat stays 25 and the chain stays 26 support the rear wheel 6. The front ends of the seat stays 25 and the chain stays 26 extend rearward from the seat tube 23. The rear ends of the seat stays 25 and the chain stays 26 are connected to each other. The rear end of the chain stay 26 is connected to the rear end of the seat stay 25.

[0066] The body frame 2 configured in this manner rotatably supports the front fork 3 via the head tube 21. The body frame 2 supports the saddle 7 via the seat tube 23. The body frame 2 rotatably supports the crankshaft 10 via the connection between the down tube 22 and the seat tube 23. The body frame 2 also supports the rear wheel axle 6a of the rear wheel 6 via the connection between the seat stays 25 and the chain stays 26.

[0067] The front fork 3 supports the front wheel 5. The front fork 3 includes a steering column 31, a left fork portion 32, and a right fork portion 33. The front fork 3 is configured as a pine needle fork. The lower end of the steering column 31 is connected to the upper ends of the left fork portion 32 and the right fork portion 33. The steering column 31 passes through the head tube 21. The steering column 31 is also rotatably supported by the head tube 21. The left fork portion 32 and the right fork portion 33 support a front wheel axle 5a of the front wheel 5. The handlebars 4 are attached to the upper end of the steering column 31 via a stem 4a.

[0068] 4, the crankshaft 10 supports the left crank 8 and the right crank 9. The crankshaft 10 is disposed to extend in the left-right direction of the body frame 2. Both ends of the crankshaft 10 protrude in the left-right direction of the body frame 2 to support the left crank 8 and the right crank 9. In other words, when viewed in the vertical direction, the distance W2 between both ends of the crankshaft 10 about the imaginary center plane C is longer than the width W1 in the left-right direction of the down tube 22 about the imaginary center plane C.

[0069] The left crank 8 and the right crank 9 are members that convert the pedaling force of the rider Br into rotational force. One end of the left crank 8 is connected to the left end of the crankshaft 10. One end of the right crank 9 is connected to the right end of the crankshaft 10. The other end of the left crank 8 is located to the left of the one end. A left pedal 8a is rotatably supported on the other end of the left crank 8. The left pedal 8a is located to the left of the left crank 8. The other end of the right crank 9 is located to the right of the one end. A right pedal 9a is rotatably supported on the other end of the left crank 8. The right pedal 9a is located to the right of the right crank 9. Therefore, when viewed in the vertical direction, the distance W3 between the right outer edge of the left pedal 8a and the left outer edge of the right pedal 9a, with the imaginary center plane C as the center, is greater than the width W1 of the down tube 22 in the left-right direction with the imaginary center plane C as the center and the distance W2 between both ends of the crankshaft 10.

[0070] Furthermore, when viewed in the vertical direction, the distance W3 between the right outer edge of the left pedal 8a and the left outer edge of the right pedal 9a, centered on the imaginary central plane C, is smaller than the distance W4 between the left outer edge of the left fork portion 32 and the right outer edge of the right fork portion 33, centered on the imaginary central plane C. In other words, when viewed in the vertical direction, the distance W4 between the left outer edge of the left fork portion 32 and the right outer edge of the right fork portion 33 is larger than the width W1 in the left-right direction of the down tube 22, the distance W2 between both ends of the crankshaft 10, and the distance W3 between the right outer edge of the left pedal 8a and the left outer edge of the right pedal 9a.

[0071] 1 to 4, the steering assist device 40 is an electric power steering drive device that assists in steering the pedal bicycle 1. The steering assist device 40 is supported on the down tube 22. The steering assist device 40 controls the torque of the steering column 31 based on the detection value of a torque sensor 44 that detects the torque applied to the steering column 31.

[0072] The steering assist device 40 includes a battery 41 , a steering assist motor 42 , a torque transmission mechanism 43 , a torque sensor 44 , and a first power harness member 45 .

[0073] The battery 41 is a power source for the steering assist motor 42. The battery 41 is configured by a known storage battery such as a lithium ion battery. The battery 41 is electrically connected to the steering assist motor 42 and the torque sensor 44. In this embodiment, the battery 41 is supported by the down tube 22. At least a portion of the battery 41 is housed inside the down tube 22.

[0074] The closer the battery 41 is positioned to the lower end of the down tube 22, the closer it is to the road surface on which the front wheel 5 and rear wheel 6 are in contact with the ground. When tilting left or right around the center of rotation at the contact point G (see Figure 5) between the front wheel 5 and rear wheel 6 and the road surface, the moment of inertia of the pedaled bicycle 1 around the center of rotation becomes smaller as the center of gravity of the pedaled bicycle 1 is moved closer to the center of rotation. The smaller the moment of inertia around the center of rotation, the easier it is to tilt left or right.

[0075] The steering assist motor 42 outputs torque to the steering column 31. The steering assist motor 42 is an electric motor that is operated by power from the battery 41. In this embodiment, the steering assist motor 42 is supported on the lower surface of the down tube 22.

[0076] The torque transmission mechanism 43 changes (increases or decreases) the torque output by the steering assist motor 42 and transmits it to the steering column 31. The torque transmission mechanism 43 is connected to the steering assist motor 42 and the steering column 31. The torque transmission mechanism 43 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 42 to the steering column 31.

[0077] As shown in Figure 4, the torque transmission mechanism 43 has an input gear 431 fixed to the output shaft of the steering assist motor 42 and an output gear 432 fixed to the steering column 31. The input gear 431 is configured by a bevel gear. The output gear 432 is configured by, for example, a sector-shaped bevel gear. The diameter of the output gear 432 is larger than the diameter of the input gear 431. Therefore, the torque transmission mechanism 43 amplifies the torque output by the steering assist motor 42 and transmits it to the steering column 31. In this embodiment, the torque transmission mechanism 43 is supported on the lower surface of the down tube 22.

[0078] The torque sensor 44 detects the torque applied to the steering column 31. The torque sensor 44 is provided on the stem 4a that supports the handlebars 4. The torque sensor 44 is, for example, a strain gauge that detects strain around the rotation axis of the steering column 31. The torque sensor 44 transmits a torque detection signal to a control device of the steering assist device 40 (not shown).

[0079] The first power supply harness member 45 is a harness that electrically connects the battery 41 and the steering assist motor 42. The first power supply harness member 45 transmits electric power from the battery 41 to the steering assist motor 42. In this embodiment, the first power supply harness member 45 is wired inside the down tube 22.

[0080] The battery 41, steering assist motor 42, torque transmission mechanism 43, and first power source harness member 45 included in the steering assist device 40 are positioned forward of the midpoint M of the line segment connecting the front wheel axle 5a and rear wheel axle 6a of the pedal bicycle 1 when viewed from the left to right of the pedal bicycle 1. Furthermore, the battery 41, steering assist motor 42, torque transmission mechanism 43, and first power source harness member 45 included in the steering assist device 40 are positioned forward of the rotation center P of the crankshaft 10, which is the rotation center of the left crank 8 and the right crank 9.

[0081] The weight of the battery 41, steering assist motor 42, torque transmission mechanism 43, and first power harness member 45 applied to the front axle 5a is determined by the ratio of the distance between the rear axle 6a and the composite center of gravity of the battery 41, steering assist motor 42, torque transmission mechanism 43, and first power harness member 45 to the distance between the front axle 5a and the rear axle 6a. The battery 41, steering assist motor 42, torque transmission mechanism 43, and first power harness member 45, which are located forward of the midpoint M and the center of rotation P, are positioned so that the distance between the rear axle 6a and the composite center of gravity is greater than the distance between the front axle 5a and the composite center of gravity. Therefore, the weight of the battery 41, steering assist motor 42, torque transmission mechanism 43, and first power harness member 45 is applied more heavily to the front axle 5a than to the rear axle 6a (see white arrows F1 and F2 in FIG. 1 ).

[0082] At least a portion of the battery 41, steering assist motor 42, torque transmission mechanism 43, and first power harness member 45 are positioned so as to overlap the down tube 22 when viewing the pedaled bicycle 1 from above. The centers of gravity of the battery 41, steering assist motor 42, torque transmission mechanism 43, and first power harness member 45 are located near the imaginary central plane C. Therefore, in the pedaled bicycle 1, imbalance in the left-right weight balance caused by the installation of the battery 41, steering assist motor 42, torque transmission mechanism 43, and first power harness member 45 is suppressed.

[0083] In this embodiment, the battery 41, steering assist motor 42, torque transmission mechanism 43 and first power harness member 45 may be arranged so as to overlap with an imaginary center plane C (see Figures 2 and 5) that passes through the left-right center line, which is the axis of the down tube 22, when viewing the pedal-equipped bicycle 1 from above and below.

[0084] The steering assist device 40 configured as described above controls the steering assist motor 42 using a control device (not shown) based on a torque signal detected by the torque sensor 44. The torque output by the steering assist motor 42 is transmitted to the steering column 31 via the torque transmission mechanism 43.

[0085] <Body behavior when pedaling> Using Figures 5 to 7, we will explain how the rider Br controls the pedaled bicycle 1 when the rider Br depresses the left pedal 8a and right pedal 9a. Figure 5 is a front view of the pedaled bicycle 1 when the rider Br is not depressing the left pedal 8a or right pedal 9a. Figure 6 is a front view of the pedaled bicycle 1 when the left pedal 8a of the pedaled bicycle 1 is tilted to the right when the rider Br depresses the left pedal 8a. Figure 7 is a front view of the pedaled bicycle 1 when the rider Br depresses the right pedal 9a of the pedaled bicycle 1. In the following description, it is assumed that the rider Br of the pedaled bicycle 1 is standing up from the saddle 7 while riding.

[0086] As shown in Figure 5, the imaginary center plane C of the pedaled bicycle 1, which is not tilted to the left or right, is located at the neutral position N. At this time, the weight of the rider Br is evenly applied to the left pedal 8a and the right pedal 9a of the pedaled bicycle 1.

[0087] As shown in Figure 6, when a rider Br of a pedal-equipped bicycle 1 depresses the left pedal 8a (see arrow A1 in Figure 6), the rider pulls the left part of the handlebar 4 upward with his or her left hand (see arrow A2 in Figure 6) to absorb the upward reaction force generated by depressing the left pedal 8a. A downward force is applied to the rider Br's body.

[0088] When the rider Br pulls the left part of the handlebars 4 upward in accordance with the magnitude of the pedaling force on the left pedal 8a, the pedaled bicycle 1 is tilted to the right of the neutral position N around the contact point G of the front wheel 5 and rear wheel 6 with the road surface as the center of rotation. At this time, the rider Br shifts the center of gravity of his or her body leftward relative to the pedaled bicycle 1 in order to maintain the direction of travel of the pedaled bicycle 1, whose center of gravity has shifted to the right. As a result, the position of the combined center of gravity CG of the rider Br's center of gravity and the center of gravity of the pedaled bicycle 1 is maintained near the neutral position N when viewed in the front-to-rear direction.

[0089] When the driver Br moves the left pedal 8a to the lowest position, he or she finishes pulling up the left part of the steering wheel 4. Next, the driver Br starts to depress the right pedal 9a, and starts to pull up the right part of the steering wheel 4 in the upward direction to receive the upward reaction force generated by depressing the right pedal 9a.

[0090] As shown in Figure 7, the rider Br of the pedaled bicycle 1, which is tilted to the right of the neutral position N, depresses the right pedal 9a (see arrow A3) and pulls the right part of the handlebar 4 upward with his or her right hand (see arrow A4) to receive the upward reaction force generated by the pedaling. A downward force is applied to the rider Br's body. As a result, the rider Br is moved from a position tilted to the right of the neutral position N toward the neutral position N, with the ground contact position G of the front wheel 5 and rear wheel 6 as the center of rotation.

[0091] When the rider Br pulls the right part of the handlebars 4 upward in accordance with the magnitude of the pedaling force on the right pedal 9a, the pedaled bicycle 1 is tilted to the left of the neutral position N around the contact point G of the front wheel 5 and rear wheel 6 with the road surface as the center of rotation. At this time, the rider Br shifts the center of gravity of his or her body to the right relative to the pedaled bicycle 1 in order to move the pedaled bicycle 1 straight, with its center of gravity shifted to the left. As a result, the position of the combined center of gravity CG of the rider Br's center of gravity and the center of gravity of the pedaled bicycle 1 is maintained near the neutral position N when viewed from the front to rear direction.

[0092] To maintain the position of the composite center of gravity CG near the neutral position N, the rider Br of the pedaled bicycle 1 leans the pedaled bicycle 1 to the right in accordance with the pressure on the left pedal 8a, and leans the pedaled bicycle 1 to the left in accordance with the pressure on the right pedal 9a. When performing dancing, which is an operation in which the rider depresses the left pedal 8a and the right pedal 9a while standing up from the saddle 7 to transmit greater driving force to the rear wheel 6, the rider Br increases the left-right tilt of the pedaled bicycle 1 more than when seated in the saddle 7. In this way, the pedaled bicycle 1 moves straight without turning by adjusting the direction and amount of lean in accordance with the weight of the pedaled bicycle 1 and the pressure on the left pedal 8a and the right pedal 9a.

[0093] The center of gravity of the pedaled bicycle 1 shifts left or right from the imaginary center plane C as the battery 41, steering assist motor 42, torque transmission mechanism 43, and first power harness member 45 are disposed further left or right from the imaginary center plane C. Therefore, with the pedaled bicycle 1, as the amount of deviation of the center of gravity from the imaginary center plane C in one left or right direction increases, the difference between the amount of left or right tilt and the amount of left or right tilt when leaning left or right in accordance with depression of the left pedal 8a and the right pedal 9a increases. In other words, with the pedaled bicycle 1, dancing becomes less efficient and appropriate as the amount of deviation of the center of gravity from the imaginary center plane C in one left or right direction increases.

[0094] The deviation of the center of gravity of the pedaled bicycle 1 from the imaginary central plane C is suppressed by arranging the battery 41, steering assist motor 42, torque transmission mechanism 43, and first power harness member 45 so that they overlap the down tube 22. As a result, the pedaled bicycle 1 is able to suppress the difference between the amount of left-right tilt and the amount of left-right tilt in response to depression of the left pedal 8a and the right pedal 9a. This allows for efficient and appropriate dancing.

[0095] In addition, by arranging the battery 41, the steering assist motor 42, the torque transmission mechanism 43, and the first power harness member 45 so that they overlap the down tube 22, the distance between the battery 41, the steering assist motor 42, the torque transmission mechanism 43, and the first power harness member 45 and the legs of the driver Br is increased. This ensures freedom of movement for the legs of the driver Br, which are located to the left and right of the battery 41, the steering assist motor 42, the torque transmission mechanism 43, and the first power harness member 45.

[0096] Furthermore, in the pedal bicycle 1, the weight of the battery 41, steering assist motor 42, torque transmission mechanism 43, and first power harness member 45 is more heavily weighted on the front axle 5a than on the rear axle 6a, increasing the frictional force generated between the front wheel 5 and the road surface. This allows the torque of the steering assist motor 42 to be efficiently transmitted to the road surface. In this way, by utilizing the weight of the battery 41, steering assist motor 42, torque transmission mechanism 43, and first power harness member 45, the control accuracy of the steering assist device 40 can be improved.

[0097] Furthermore, the battery 41, steering assist motor 42, torque transmission mechanism 43, and first power harness member 45 are located rearward of the head tube 21 and forward of the midpoint M of the line segment connecting the front axle 5a and the rear axle 6a. The combined center of gravity CG of the pedaled bicycle 1 with the rider Br on board is located rearward of the head tube 21 and forward of the midpoint M of the line segment connecting the front axle 5a and the rear axle 6a. Therefore, the battery 41, steering assist motor 42, torque transmission mechanism 43, and first power harness member 45 are located near the yaw axis passing through the combined center of gravity CG of the pedaled bicycle 1. This minimizes an increase in the moment of inertia about the yaw axis due to the installation of the battery 41, steering assist motor 42, torque transmission mechanism 43, and first power harness member 45. The maneuverability of the pedaled bicycle 1 during turning is affected by the magnitude of the moment of inertia about the yaw axis. The steering assist device has improved responsiveness due to the suppression of the moment of inertia around the yaw axis, making it easier for the steering assist device 40 to exert its turning function.

[0098] [Modification of Embodiment 1] A pedaled bicycle 1A, which is a modification of the pedaled bicycle 1 of the present invention, will be described using Figure 8. Figure 8 is a side view of the pedaled bicycle 1A according to a modification of Embodiment 1 of the present invention. Note that in the following embodiment, specific descriptions of the same points as in the embodiments already described will be omitted, and the description will focus on the differences.

[0099] As shown in FIG. 8, the pedal bicycle 1A has a steering assist device 40.

[0100] The steering assist motor 42 of the steering assist device 40 is supported by the down tube 22. The steering assist motor 42 is housed inside the down tube 22. In this case, the steering assist motor 42 is disposed so as to overlap with the imaginary center plane C (see FIG. 2) of the down tube 22 when viewed in the up-down direction.

[0101] Therefore, the battery 41, steering assist motor 42, torque transmission mechanism 43, and first power harness member 45 are housed in the hollow portion of the down tube 22, and are arranged such that the imaginary center plane C in the left-right direction of the down tube 22 and the rotation axis of the steering assist motor 42 are close to each other. This maintains a substantially equal weight balance in the left-right direction of the pedal-equipped bicycle 1A. This further reduces the deterioration of maneuverability when leaning the vehicle body left and right in response to depression of the left pedal 8a and the right pedal 9a.

[0102] 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.

[0103] In the above-described embodiment, the pedal bicycle 1, 1A has a head tube 21, a down tube 22, a seat tube 23, and a top tube 24. However, it is sufficient for the pedal bicycle to have a head tube, a down tube, and a seat tube.

[0104] In the above-described first embodiment, the battery 41, steering assist motor 42, torque transmission mechanism 43, and first power source harness member 45 are arranged so as to overlap the down tube 22 when viewing the pedaled bicycle 1 in the vertical direction. However, it is sufficient that the battery, steering assist motor, torque transmission mechanism, and first power source harness member are arranged so that at least a portion of them overlap the down tube when viewing the pedaled bicycle in the vertical direction.

[0105] In the above-described first embodiment, the battery 41, steering assist motor 42, torque transmission mechanism 43, and first power source harness member 45 are arranged to overlap the down tube 22 when viewing the pedaled bicycle 1 in the vertical direction. However, the battery 41, steering assist motor 42, torque transmission mechanism 43, and first power source harness member 45 may also be configured to be located within a gap W3 between the right outer edge of the left pedal 8a and the left outer edge of the right pedal 9a when viewing the pedaled bicycle 1 in the vertical direction (see FIG. 4).

[0106] As shown in FIG. 4 , the distance W3 is narrower than the distance between the rider Br's left leg, which is placed to the left of the right outer edge of the left pedal 8a, and the rider Br's right leg, which is placed to the right of the left outer edge of the right pedal 9a. Therefore, the battery 41, steering assist motor 42, torque transmission mechanism 43, and first power harness member 45, which are located between the right outer edge of the left pedal 8a and the left outer edge of the right pedal 9a, are prevented from interfering with the rider Br's left leg, which is placed on the left pedal 8a, and the rider Br's right leg, which is placed on the right pedal 9a. This ensures freedom of leg movement for the rider Br in the pedal-equipped bicycle 1 equipped with the steering assist device 40. Furthermore, because the battery 41, steering assist motor 42, torque transmission mechanism 43, and first power harness member 45 are positioned within the distance W3 centered on the imaginary center plane C when viewed vertically, imbalance in the left-right weight balance is reduced. This makes it possible to suppress a decrease in operability with respect to the left and right tilt operation by the driver Br in accordance with depression of the left pedal 8a and the right pedal 9a.

[0107] In addition, the battery 41, steering assist motor 42, torque transmission mechanism 43 and first power harness member 45 may be configured to be located within the space W2 between both ends of the crankshaft 10 when viewing the pedal bicycle 1 from above and below (see Figure 4).

[0108] 4, the distance W2 is narrower than the distance between the rider's left leg, which is placed to the left of the right outer edge of the left pedal 8a, and the rider's right leg, which is placed to the right of the left outer edge of the right pedal 9a. Therefore, the battery 41, steering assist motor 42, torque transmission mechanism 43, and first power harness member 45, which are located between the right outer edge of the left pedal 8a and the left outer edge of the right pedal 9a, are positioned farther toward the down tube 22 from the rider's left leg, which is placed to the left of the right outer edge of the left pedal 8a and is placed on the left pedal 8a, and the rider's right leg, which is placed to the right of the left outer edge of the right pedal 9a. Therefore, the pedal-equipped bicycle 1 having the steering assist device 40 can further ensure freedom of leg movement for the rider Br. Furthermore, the battery 41, the steering assist motor 42, the torque transmission mechanism 43, and the first power harness member 45 are arranged within a distance W2 centered on the imaginary center plane C when viewed in the vertical direction, thereby suppressing imbalance in the weight balance in the left-right direction, thereby suppressing deterioration in operability when the driver Br tilts left and right in accordance with depression of the left pedal 8a and the right pedal 9a.

[0109] In addition, the battery 41, steering assist motor 42, torque transmission mechanism 43 and first power harness member 45 may be configured to be located between the left and right outer edges of the down tube 22 when looking at the pedal-equipped bicycle 1 from above and below (see Figure 4).

[0110] As shown in Figure 4, the battery 41, steering assist motor 42, torque transmission mechanism 43, and first power harness member 45, which are located within a width W1 of the down tube 22 centered on the imaginary central plane C, are located close to the axis of the down tube 22 within the left-right width of the down tube 22. This allows the rider Br greater freedom in leg movement in a pedal-equipped bicycle 1 equipped with the steering assist device 40. Furthermore, the placement of the battery 41, steering assist motor 42, torque transmission mechanism 43, and first power harness member 45 reduces imbalances in the left-right weight balance of the pedal-equipped bicycle 1. This reduces a decrease in operability when the rider Br leans left or right in conjunction with depressing the left pedal 8a and right pedal 9a.

[0111] In addition, the battery 41, steering assist motor 42, torque transmission mechanism 43 and first power harness member 45 may be configured to be located within a distance W4 between the left outer edge of the left fork section 32 and the right outer edge of the right fork section 33, with the virtual center plane C as the center, when viewing the pedaled bicycle 1 from above and below (see Figure 4).

[0112] As shown in FIG. 4 , the distance W4 is wider than the distance W3 between the right outer edge of the left pedal 8a and the left outer edge of the right pedal 9a. Therefore, the battery 41, steering assist motor 42, torque transmission mechanism 43, and first power source harness member 45 are not located laterally outward of the front fork 3 in a longitudinal view. Therefore, the front fork 3 of the pedaled bicycle 1 prevents contact between the battery 41, steering assist motor 42, torque transmission mechanism 43, and first power source harness member 45 and obstacles approaching from the front of the pedaled bicycle 1, while also preventing imbalances in the left-right weight balance of the pedaled bicycle due to the placement of the battery 41, steering assist motor 42, torque transmission mechanism 43, and first power source harness member 45. This prevents a decrease in operability when the rider Br leans left or right in conjunction with depressing the left pedal 8a and right pedal 9a.

[0113] In the above-described first embodiment, the battery 41, the steering assist motor 42, the torque transmission mechanism 43, and the first power harness member 45 are disposed inside the down tube 22. However, the battery, the steering assist motor, the torque transmission mechanism, and the first power harness member may be disposed so that at least a portion thereof is located outside the down tube and at least a portion thereof overlaps with the down tube when the pedal-equipped bicycle is viewed in the vertical direction.

[0114] In the above-described first embodiment, the battery 41, steering assist motor 42, torque transmission mechanism 43, and first power harness member 45 are arranged so as to overlap the axis of the down tube 22 when the pedaled bicycle 1 is viewed vertically. However, the battery, steering assist motor, torque transmission mechanism, and first power harness member may also be arranged so that at least a portion of them overlaps with the down tube but does not overlap with the axis of the down tube when the pedaled bicycle is viewed vertically.

[0115] In the above-described first embodiment, the battery 41, the steering assist motor 42, the torque transmission mechanism 43, and the first power harness member 45 are supported by the down tube 22. However, the battery, the steering assist motor, the torque transmission mechanism, and the first power harness member may be arranged so that at least a portion of them overlaps with the down tube when viewed from above and below the bicycle with pedals, while being supported by at least one of the head tube, the top tube, or the seat tube.

[0116] In the above-described embodiment, the steering assist motor 42 is disposed on the lower surface of the down tube 22. Furthermore, in a modification of the above-described embodiment, the steering assist motor 42 is disposed inside the down tube 22. However, the steering assist motor may also be disposed on the upper surface of the down tube.

[0117] In the above-described embodiment, the torque transmission mechanism 43 is disposed on the lower surface of the down tube 22 or inside the down tube 22. However, the torque transmission mechanism may also be disposed on the upper surface of the down tube or the top tube. Furthermore, the torque transmission mechanism may also be housed in the head tube or disposed outside the body frame.

[0118] In the above-described embodiment, the steering assist motor 42 is disposed closer to the head tube 21 than the battery 41. However, the steering assist motor may be disposed farther from the head tube than the battery 41, or may be disposed at the same distance from the head tube as the battery. Furthermore, either the steering assist motor or the battery may be disposed outside the down tube, or may be disposed inside the top tube.

[0119] In each of the above-described embodiments, the steering assist device 40 has the steering assist motor 42 as an actuator. However, the actuator of the steering assist device may be an electric actuator such as an electric cylinder.

[0120] 1, 1A Pedaled bicycle 2 Body frame 3 Front fork 4 Handlebars 4a Stem 5 Front wheel 5a Front wheel axle 6 Rear wheel 6a Rear wheel axle 7 Saddle 8 Left crank 8a Left pedal 9 Right crank 9a Right pedal 10 Crankshaft 21 Head tube 22 Down tube 23 Seat tube 24 Top tube 25 Seat stay 26 Chain stay 31 Steering column 32 Left fork section 33 Right fork section 40 Steering assist device 41 Battery 42 Steering assist motor 43 Torque transmission mechanism 44 Torque sensor 45 First power supply harness member 431 Input gear 432 Output gear A1 Arrow indicating pressing down on left pedal A2 Arrow indicating lifting up on left part of handlebar A3 Arrow indicating pressing down on right pedal A4 Arrow indicating lifting up on right part of handlebar F1 Load applied to the front axle F2 Load applied to the rear axle C Virtual center plane N Neutral position G Ground contact position Br Rider CG Composite center W1 Width of the down tube in the left-to-right direction W2 Distance between both ends of the crankshaft W3 Distance between the right outer edge of the left pedal and the left outer edge of the right pedal W4 Distance between the left outer edge of the left fork section and the right outer edge of the right fork section

Claims

1. A vehicle frame including a head tube and a down tube that extends diagonally, with its front end connected to the rear edge of the head tube and its rear end positioned lower than the front end, A front wheel supported by a front fork including a steering column rotatably supported on the head tube, The rear wheels are supported by the aforementioned vehicle frame, The left crank and right crank are supported by the aforementioned vehicle frame, A pedal-assisted bicycle having a steering assist device including a steering assist motor, a battery that supplies power to the steering assist motor, a first power harness member that electrically connects the steering assist motor and the battery, a control device that controls the steering assist motor, and a torque transmission mechanism that transmits the torque of the steering assist motor to the steering column, The steering assist device is, It has a torque sensor that detects the torque applied to the steering column, The steering assist motor, the battery, the first power harness member, and the torque transmission mechanism are as follows: (1) When the pedal bicycle is viewed from left to right, the entire assembly is positioned in front of the midpoint of the line segment connecting the axle of the front wheel and the axle of the rear wheel of the pedal bicycle, and the centers of rotation of the left crank and the right crank, (2) When viewed in the vertical direction, the pedal-equipped bicycle is positioned such that at least a portion of it overlaps with the down tube, The control device is The steering assist motor is controlled based on the torque signal from the torque sensor. A bicycle with pedals.

2. In the pedal bicycle described in claim 1, The steering assist motor, the battery, the first power harness member, and the torque transmission mechanism are as follows: When viewing the aforementioned pedal-equipped bicycle in the vertical direction, the position located between the right outer edge of the left pedal supported by the left crank and the left outer edge of the right pedal supported by the right crank is: A bicycle with pedals.

3. In the pedal bicycle described in claim 1, The steering assist motor, the battery, the first power harness member, and the torque transmission mechanism are as follows: When viewing the aforementioned bicycle with pedals in the vertical direction, the following is located between the ends of the crank axle connecting the left crank and the right crank: A bicycle with pedals.

4. In the pedal bicycle according to claim 1 or 2, The steering assist motor, the battery, the first power harness member, and the torque transmission mechanism are as follows: When viewing the aforementioned pedal-equipped bicycle in the vertical direction, the position located between the left outer edge and the right outer edge of the down tube is: A bicycle with pedals.

5. In a pedal bicycle according to any one of claims 1 to 3, The steering assist motor, the battery, the first power harness member, and the torque transmission mechanism are as follows: When viewing the aforementioned pedal-equipped bicycle in the vertical direction, the front fork is located between the left outer edge of the left fork portion that supports the front wheel and the right outer edge of the right fork portion, A bicycle with pedals.