Electrically assisted bicycles

Abstract

To provide an electric power assist bicycle which allows a user who walks while pushing the bicycle or supports the bicycle beside the bicycle to walk easily when the user walks while pushing the bicycle by outputting auxiliary power generated by a motor to a wheel side or when a self-propelled mode is executed.SOLUTION: An electric power assist bicycle can execute a self-propelled mode or allows a user to walk while pushing the bicycle in such a manner that a rotation force of a crank shaft, which is rotated by a human power driving force generated by a stepping force of a left pedal 8a and a right pedal is transmitted to wheel sides through a one-way clutch and auxiliary power generated by a motor is output to the wheel sides. A weight of a left pedal side member, which is connected to a left side of the crank shaft and includes the left pedal 8a, is different from a weight of a right pedal side member, which is connected to a right side of the crank shaft and includes the right pedal.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present disclosure relates to an electrically assisted bicycle, and more particularly to an electrically assisted bicycle that can implement a mode in which auxiliary power from a motor is output to the wheel side so that the bicycle can be pushed or self-propelled. [Background technology]

[0002] Patent document 1 describes a configuration for an electrically assisted bicycle that allows a user to dismount from the bicycle and operate an operating unit attached near the grip of the handlebars to activate a second mode in which the motor generates auxiliary power to push the bicycle or to propel the bicycle by itself.

[0003] In typical electrically assisted bicycles, including the bicycle of Patent Document 1, the rotational force of the crankshaft, which rotates due to human driving force generated by pedaling force, is transmitted to the wheel side via a one-way clutch. A one-way clutch is composed of, for example, an inner (or outer) that is fixed to the crankshaft, and an outer (or inner) that is fixed to the front sprocket. The one-way clutch is structured so that when the user pedals and the crankshaft rotates in the forward direction (the direction that moves the bicycle forward), the pawl of the inner catches in the groove of the outer, and the rotational force in the forward direction is transmitted to the front sprocket. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-177719 A Summary of the Invention [Problem to be solved by the invention]

[0005] When the motor outputs auxiliary power during the second mode, which is when the user is walking without putting their feet on the pedals or when the bicycle is self-propelled, the rotation of the front sprocket causes the crankshaft to rotate due to frictional force generated in the one-way clutch, which tends to cause the pedals to rotate together. If the pedals rotate together during the second mode, it is easy to imagine that the pedals would hit the user's feet, making it difficult to walk.

[0006] The object of the present disclosure is to make it easier for a user pushing or supporting an electrically assisted bicycle to walk next to the bicycle when the bicycle is in a mode in which auxiliary power from the motor is output to the wheel side to push the bicycle or to propel the bicycle itself. [Means for solving the problem]

[0007] One aspect of the electric assisted bicycle of the present disclosure is an electric assisted bicycle in which the rotational force of the crankshaft, which rotates due to human driving force generated by the force applied to the left and right pedals, is transmitted to the wheel side via a one-way clutch, and auxiliary power from the motor is output to the wheel side, allowing the bicycle to be pushed or self-propelled, and in which the weight of the left pedal side member connected to the left side of the crankshaft and including the left pedal is different from the weight of the right pedal side member connected to the right side of the crankshaft and including the right pedal. Effect of the Invention

[0008] According to the electrically assisted bicycle of the present disclosure, when the auxiliary power of the motor is output to the wheel side to push the bicycle or to propel the bicycle by itself, even if the crankshaft tends to rotate due to the auxiliary power of the motor via the one-way clutch, the rotation of the crankshaft stops when one of the two pedals on the left and right is lowered. This prevents the pedals from rotating together, making it easier for the user pushing or supporting the bicycle next to the bicycle to walk. [Brief description of the drawings]

[0009] [Figure 1]FIG. 2 is a right side view of the electrically assisted bicycle according to the embodiment. [Diagram 2] 2 is a diagram showing the vicinity of the left pedal side member when viewed from the left side of the electrically assisted bicycle in FIG. 1. FIG. [Diagram 3] 2 is a diagram showing the rear part of the electrically assisted bicycle with a unit case of a motor unit and a part of a chain case omitted from FIG. 1. [Figure 4] 1 is a block diagram of a configuration focusing on a control device in an electrically assisted bicycle according to an embodiment. [Diagram 5] 2 is a cross-sectional view showing a rotation support structure for a crankshaft of a motor unit in an embodiment. FIG. [Figure 6] 6 is a cross-sectional view taken along line AA in FIG. 5. [Figure 7] FIG. 2 is a top view of the left pedal in the embodiment. [Figure 8] FIG. 8 is a side view of the left pedal of FIG. 7. [Figure 9] 3 is a view corresponding to FIG. 2 and showing a state in which the left pedal is stopped on the lower side when the second mode is executed. FIG. [Figure 10] FIG. 11 is a perspective view of a left pedal in a modified example of the embodiment, in which a pedal shaft is omitted. [Figure 11] FIG. 11 is a top view of the left pedal in FIG. 10. [Figure 12] FIG. 11 is a perspective view of a metal part to be assembled into the left pedal of FIG. 10. [Figure 13] FIG. 10 is a perspective view of a chain drive mechanism in another embodiment. [Figure 14] FIG. 11 is a top view of the left and right pedals in another embodiment. [Figure 15] FIG. 15 is a side view of the left and right pedals of FIG. 14. [Figure 16] FIG. 11 is a top view of the left pedal in another embodiment. [Figure 17] FIG. 17 is a side view of the left pedal of FIG. 16. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] An electric power-assisted bicycle according to an embodiment of the present disclosure will be described in detail below with reference to the drawings. The materials, shapes, and positions described below are examples for the purpose of explanation and can be changed as appropriate according to the specifications of the electric power-assisted bicycle. In the following description, the same reference numerals are used to designate equivalent elements in all drawings.

[0011] FIG. 1 is a right-side view of an electrically power-assisted bicycle 1 according to an embodiment. FIG. 2 is a left-side view of the electrically power-assisted bicycle 1, showing the left pedal-side member 6a and its vicinity. FIG. 3 is a rear-side view of the electrically power-assisted bicycle 1, with part of the unit case 64 and the chain case 63 of the motor unit 11 omitted from FIG. 1. Note that the electrically power-assisted bicycle according to the present disclosure is not limited to a city bicycle as shown in FIG. 1, and may be, for example, a sports bicycle, a folding bicycle, or the like. In the following, for the sake of convenience, terms indicating directions such as up / down, left / right, and front / rear are used, but these terms refer to the up / down, left / right, and front / rear directions of the electrically power-assisted bicycle 1 and each component in a normal state of use.

[0012] As shown in Fig. 1, the power-assisted bicycle 1 is a bicycle that can operate in a first mode as an assist mode by depressing two pedals 8a (Fig. 2) and 8b on the left and right, and a second mode in which auxiliary power from a motor 12 (Fig. 4) is output to the wheels to travel the bicycle without a user riding it. The first and second modes will be described in detail later.

[0013] The power-assisted bicycle 1 includes a frame 2, a front wheel 3a, a rear wheel 3b, a handlebar 4, a saddle 5, a left pedal side member 6a (Fig. 2), a right pedal side member 6b, a chain 60, and a headlight 9. The left pedal side member 6a includes a left crank arm 7a and a left pedal 8a. The right pedal side member 6b includes a right crank arm 7b and a right pedal 8b. The power-assisted bicycle 1 also includes a battery 10 and a motor unit 11. When the first mode is executed, the power-assisted bicycle 1 assists the force (pedaling force) applied by the user to the pedals 8a, 8b with a motor 12 (Fig. 4) of the motor unit 11. The motor 12 is disposed inside a unit case 64 of the motor unit 11. The motor 12 may be attached to the outside of the motor unit 11.

[0014] One end of the left crank arm 7a and one end of the right crank arm 7b are connected to both axial ends, which are both left and right ends of the crank shaft 30 (FIG. 5). The other end of the left crank arm 7a and the right crank arm 7b are connected to the left pedal 8a and the right pedal 8b, respectively. The left crank arm 7a and the right crank arm 7b extend in opposite directions. In this embodiment, the rotational force of the crank shaft 30, which is rotated by the human driving force due to the pedaling force of the left pedal 8a and the right pedal 8b, is transmitted to the front sprocket 50 (FIGS. 3 and 5) via the one-way clutch 40 (FIG. 5). The front sprocket 50 is connected to a rear sprocket 61 (FIG. 3) provided on the rear wheel 3b as a wheel via a chain 60, which is a member on the wheel side. As a result, the pedaling force of each pedal 8a, 8b is transmitted to the rear wheel 3b via the chain 60 and the rear sprocket 61. In addition, the auxiliary power of the motor 12 is taken out to a second sprocket 62 (FIG. 3) via a reduction gear or the like, and the taken out power is transmitted from the second sprocket 62 to the rear wheel 3b via a chain 60. In addition, a part of the chain 60 is covered by a chain case 63.

[0015] In this example, the weights of the left pedal side member 6a and the right pedal side member 6b are made different, more specifically, the weight of the left pedal side member 6a is made greater than the weight of the right pedal side member 6b, as described later. This makes it possible to prevent the crankshaft 30 (Fig. 5) from rotating together with the front sprocket 50 (Figs. 3 and 5) when the second mode, such as a pushing-walking mode described later, is executed. This makes it easier for a user who is pushing or supporting the bicycle to walk next to the bicycle.

[0016] The motor unit 11 may be of a single shaft type in which the rotational force of the motor 12 is transmitted to the front sprocket 50 via a reduction gear or the like.

[0017] The frame 2 connects the front wheel 3a, the rear wheel 3b, the handlebars 4, the saddle 5, etc., and supports the battery 10 and the motor unit 11. The frame 2 is made up of a plurality of pipes. In this embodiment, the plurality of pipes include a head pipe 2a, a front fork 2b, a down pipe 2c, a seat pipe 2d, a chain stay 2e, a seat stay 2f, and a bottom bracket (not shown). The bottom bracket is a pipe that connects the down pipe 2c, the seat pipe 2d, and the chain stay 2e.

[0018] The head pipe 2a supports the front fork 2b and the handlebars 4 rotatably around the central axis of the pipe. The front fork 2b has a pair of front forks that rotatably support the front wheel 3a, and a front fork stem that extends upward from the upper ends of the front forks and is inserted into the head pipe 2a. The handlebars 4 are attached to the upper end of the steering column.

[0019] The down pipe 2c is a pipe that connects the head pipe 2a and the bottom bracket. The down pipe 2c is inclined so that it is positioned higher the closer it is to the front of the electric assisted bicycle 1. The seat pipe 2d is a pipe that holds the saddle 5, and is inclined in the vertical direction so that its upper end is positioned further back on the bicycle than its lower end. In this embodiment, the battery 10 is attached to the seat pipe 2d, and the motor unit 11 is attached to the bottom bracket.

[0020] The chain stays 2e are pipes that connect the seat stays 2f and the bottom bracket. Like the chain stays 2e, the seat stays 2f are provided on both sides of the rear wheel 3b. The rear wheel 3b is rotatably supported at the rear end of the chain stays 2e.

[0021] The battery 10 is a power supply device that supplies power to at least the motor 12 (FIG. 4) of the motor unit 11. The battery 10 may be configured to supply power to devices other than the motor unit 11, such as the headlight 9.

[0022] Fig. 4 is a block diagram of a configuration centered around the control device 20 of the electrically power-assisted bicycle 1 of the embodiment. The motor unit 11 includes a motor 12, a drive circuit 13, and the control device 20 that controls the output of the motor 12. The motor unit 11 is a drive unit that assists the pedaling force of the left pedal 8a and the right pedal 8b, and controls the output of the motor 12 based on the torque (pedaling force) acting on a crankshaft 30 (Fig. 5) that connects the two left and right crank arms 7a, 7b, and the vehicle speed. The motor unit 11 may also control the output of the motor 12 using the number of rotations of the crankshaft 30. The motor 12 may be any electric motor that can be driven by power supplied from the battery 10 to assist traveling, and a suitable example is a three-phase brushless DC motor.

[0023] The electrically power assisted bicycle 1 includes, for example, a torque sensor 14 that detects the pedaling load acting on the crankshaft 30, and a vehicle speed sensor 15 that detects the vehicle speed from the rotation speed of the wheel. The electrically power assisted bicycle 1 may also include a rotation sensor 16 that detects the rotation speed of the crankshaft 30. The detection information from these sensors is sent to the control device 20 and used to control the output of the motor 12. For example, the current supplied to the motor 12 changes when the drive circuit 13 performs a switching operation based on a control signal from the control device 20, thereby controlling the output of the motor 12.

[0024] The electrically assisted bicycle 1 has an electrically assisted function that can execute a first mode in which a first auxiliary power is output from the motor 12 in response to the human driving force applied to each pedal 8a, 8b (FIGS. 1 and 2), and a second mode in which a second auxiliary power is output from the motor 12 to push the bicycle or a second auxiliary power is output to propel the bicycle. Both of these electrically assisted functions are executed under the control of the control device 20.

[0025] The electrically assisted bicycle 1 includes a power switch 17 for activating the electrically assisted function. When the control device 20 receives an operation signal from the power switch 17, it executes a first mode that assists the pedaling force of each pedal 8a, 8b. The power switch 17 is, for example, a switch that turns ON when pressed once and turns OFF when pressed again. The electrically assisted bicycle 1 also includes a second mode switch 18 for executing a second mode. The second mode switch 18 is, for example, a switch that turns ON only while it is pressed, and the second mode is executed only when the second mode switch 18 is pressed.

[0026] The electrically assisted bicycle 1 may be provided with a switch unit (not shown) including a power switch 17, a second mode switch 18, etc. The switch unit is generally provided on the handlebars 4. In addition to the power switch 17 and the second mode switch 18, the switch unit may also be equipped with a switch for turning on the headlights 9, a switch for changing the riding mode, the assist force, etc., a display unit for displaying the remaining battery power, etc.

[0027] The second mode includes a "push walking mode" and a "self-propelled mode." The push walking mode is a mode in which, when the user pushes the bicycle, auxiliary power is output from the motor 12 to assist the user in pushing the bicycle. The push walking mode is executed when the second mode switch 18 is pressed and the user is not riding the bicycle. On the other hand, the self-propelled mode is a mode in which, while the user is supporting the bicycle, auxiliary power is output from the motor 12 to propel the bicycle by itself. In other words, the self-propelled mode differs from the push walking mode in that the user is not exerting a force pushing the bicycle forward.

[0028] Alternatively, a sensor provided on the grip of the handlebar 4 or the like may detect the force applied forward, and the push-walking mode and the self-propelled mode may be distinguished based on the magnitude of the force. Alternatively, auxiliary power may be output from the motor 12 as the second mode without distinguishing between the push-walking mode and the self-propelled mode. In either case, the control device 20 allows the second mode to be executed when the user is not riding the power-assisted bicycle 1.

[0029] The control device 20 includes a first mode execution processing unit 23 that executes the first mode, and a second mode execution processing unit 24 that executes the second mode.

[0030] The control device 20 is composed of a microcomputer equipped with a processor 21, a memory 22, and an input / output interface, etc. The processor 21 is composed of, for example, a CPU or GPU, and realizes the functions of each of the above-mentioned processing units by reading and executing a control program for the power-assisted bicycle 1. The memory 22 includes non-volatile memory such as ROM, HDD, SSD, etc., which stores the control program, etc., and volatile memory such as RAM.

[0031] For example, when the power switch 17 is ON, the first mode execution processing unit 23 obtains detection values ​​from the torque sensor 14, the vehicle speed sensor 15, and the rotation sensor 16, and outputs a first auxiliary power that assists the pedaling force of each of the pedals 8a, 8b based on the detection values. The first mode execution processing unit 23 controls the output of the motor 12 via the drive circuit 13 and adjusts the first auxiliary power based on the pedaling force load, which is the load caused by the pedaling force applied to the two pedals 8a, 8b, the bicycle speed, the rotation speed of the pedals 8a, 8b, etc.

[0032] For example, when the second mode switch 18 is ON, the second mode execution processing unit 24 drives the motor 12 to output a second auxiliary power that assists in pushing and walking. For example, the second mode execution processing unit 24 controls the output of the motor 12 via the drive circuit 13 and adjusts the second auxiliary power so that the bicycle speed does not exceed a predetermined upper limit. Furthermore, when an ON signal is obtained from the second mode switch 18, the second mode execution processing unit 24 executes the second mode only when it is determined that the user is not riding the bicycle.

[0033] The determination of whether the user is riding can be performed by a conventionally known method, such as a method using a seating sensor on the saddle 5, or a method for detecting a state in which the saddle 5 cannot be ridden on a bicycle.

[0034] FIG. 5 is a cross-sectional view showing a rotation support structure of the crankshaft 30 of the motor unit 11 in the embodiment. FIG. 6 is a cross-sectional view taken along line AA in FIG. 5, seen from the right side to the left side of the power-assisted bicycle 1. The motor unit 11 includes a crankshaft 30 at least a part of which is accommodated in a unit case 64, a one-way clutch 40 attached to the crankshaft 30, and a front sprocket 50. The front sprocket 50 is rotatably attached to the crankshaft 30, and the rotational force of the crankshaft 30 is transmitted via the one-way clutch 40. Two left and right crank arms 7a, 7b (FIGS. 1 and 2) are fixed to both axial ends of the crankshaft 30, which are both left and right ends. Two left and right pedals 8a, 8b (FIGS. 1 and 2) are connected to the two left and right crank arms 7a, 7b, respectively. The crankshaft 30 rotates when a human driving force applied to two pedals 8a, 8b on the left and right is transmitted to the crankshaft 30 via two crank arms 7a, 7b on the left and right.

[0035] Furthermore, the motor unit 11 includes, for example, a speed reduction mechanism (not shown), and auxiliary power output from the motor 12 is transmitted to the rear wheel 3b via the speed reduction mechanism, a second sprocket 62 (Fig. 3) for outputting auxiliary power, and the chain 60. More specifically, when the second sprocket 62 rotates counterclockwise in Fig. 3 due to the rotation of the motor 12, the chain 60 moves in the direction of arrow A1, and accordingly the rear sprocket 61 and front sprocket 50 around which the chain 60 is wound rotate clockwise in Fig. 3, causing the rear wheel 3b to rotate in the direction of arrow A2. This causes the power-assisted bicycle 1 to travel forward (in the direction of arrow A3).

[0036] The drive circuit 13, the control device 20, the one-way clutch 40, and the reduction mechanism are housed in a unit case 64 (FIG. 5) of the motor unit 11. The unit case 64 is fixed to a frame 2 such as a bottom bracket. Also provided in the unit case 64 are the torque sensor 14, a bearing 33 that rotatably supports the crankshaft 30, and the like. The bearings 33 are, for example, ball bearings, and are provided near both axial ends of the crankshaft 30.

[0037] The crankshaft 30 is rotatably supported by bearings 33 fixed to the unit case 64, with both axial ends protruding outward from the unit case 64. Two left and right crank arms 7a, 7b (FIGS. 1 to 3) fixed to both axial ends of the crankshaft 30, respectively, have the same weight.

[0038] On the other hand, the left pedal 8a and the right pedal 8b attached to both axial ends of the crankshaft 30 via crank arms 7a, 7b have different weights.

[0039] FIG. 7 is a top view of the left pedal 8a in the embodiment. FIG. 8 is a side view of the left pedal 8a. The left pedal 8a includes a pedal body 70 having a substantially rectangular parallelepiped shape with a tread surface, and a pedal shaft 72 rotatably supported at the center of the pedal body 70 and having a tip end protruding toward the left crank arm side (the left side of FIGS. 7 and 8). A male screw may be formed at the tip end of the pedal shaft 72 protruding from the side surface of the pedal body 70 for attachment to the other end of the left crank arm 7a (FIG. 2). Through holes 71 are formed at a plurality of positions in the pedal body 70, penetrating the pedal body 70 in the thickness direction. The pedal body 70 is formed of a resin molded body 70a. Furthermore, a thin plate-shaped metal part 74 made of iron or the like is insert-molded inside the resin molded body 70a that forms the pedal body 70. Since the through hole 71 is formed in the pedal body 70, a through hole may be formed in the metal part 74 in accordance with the through hole 71. Note that a recess may be formed in the pedal body 70 instead of the through hole 71.

[0040] Like the left pedal 8a, the right pedal 8b is also configured to include a pedal body 70 (FIG. 3) formed of a resin molded body and a pedal shaft, but unlike the left pedal 8a, the right pedal 8b does not include a thin plate-shaped metal part 74 (FIGS. 7 and 8). As a result, the left pedal 8a is heavier than the right pedal 8b by the weight of the metal part 74. The metal part 74 is provided to provide a predetermined weight difference between the left pedal 8a and the right pedal 8b. Preferably, the metal part 74 has a weight of 50 g to 500 g. More preferably, the metal part 74 has a weight of 60 g to 300 g. Even more preferably, the metal part 74 has a weight of 80 g to 120 g. As a result, the weight difference between the left pedal 8a and the right pedal 8b is preferably 50 g to 150 g, more preferably 60 g to 300 g, and even more preferably 80 g to 120 g. If the weight of the metal part 74 is limited to such a range, the user will not feel the weight difference between the left and right pedals 8a, 8b when riding the bicycle and pedaling the pedals 8a, 8b. On the other hand, the weight of the metal part 74 is not limited to the above range, and may be any weight that makes it difficult for the user to feel the weight difference between the left and right pedals 8a, 8b when riding the bicycle. By making the weights of the two left and right pedals 8a, 8b different as described above, the weight of the left pedal side member 6a and the weight of the right pedal side member 6b are different. This makes it possible to suppress the co-rotation of the pedals 8a, 8b when the second mode is executed, as described later.

[0041] Returning to Fig. 5, the tubular body 31 is attached to the crankshaft 30 within the unit case 64. The tubular body 31 is fixed to the crankshaft 30 by a plurality of axial grooves called a spline joint (or a serration joint) and their fitting parts so that relative rotation is impossible. Furthermore, a magnetostrictive torque sensor 14 is disposed around the tubular body 31. The tubular body 31 fixed to the crankshaft 30 is twisted by the pedaling force of the pedals 8a, 8b, and the degree of the twisting changes depending on the pedaling force, so that the pedaling force load can be detected using the magnetostrictive torque sensor 14.

[0042] The one-way clutch 40 includes an outer clutch 41 that is fixed to the cylindrical body 31 and has grooves formed at multiple positions in the circumferential direction on its inner peripheral surface, and an inner clutch 42 that is fixed to the front sprocket 50. In this embodiment, one end of the inner clutch 42 protrudes outward from the unit case 64, and the front sprocket 50 is fixed to this end. The outer clutch 41 is also fixed to the crankshaft 30 via the cylindrical body 31. That is, the inner clutch 42 rotates integrally with the front sprocket 50, and the outer clutch 41 rotates integrally with the crankshaft 30.

[0043] Both the outer 41 and the inner 42 are cylindrical bodies through which the crankshaft 30 can be inserted. For example, the inner 42 is inserted into the cylinder of the outer 41 and arranged so as to overlap in the radial direction of the crankshaft 30. The inner 42 is biased toward the outer 41 to contact the inner circumferential surface of the outer 41, and is provided with a pawl 43 that is urged toward the outer 41 and comes into contact with the inner circumferential surface of the outer 41, and that catches in a groove 41a of the outer 41 when the crankshaft 30 rotates in the forward direction, that is, the direction of arrow B in FIG. 6. Note that the pawl 43 is configured not to catch in the groove 41a of the outer 41 when the crankshaft 30 rotates in the reverse direction (the direction opposite to the direction of arrow B in FIG. 6). Here, the forward rotation means a rotation in a direction that moves the power-assisted bicycle 1 forward.

[0044] The one-way clutch 40 has a structure in which, when the user pedals the pedals 8a, 8b and the crankshaft 30 rotates in the forward direction, the pawls 43 of the inner clutch 42 get caught in the grooves 41a of the outer clutch 41, and the rotational force in the forward direction is transmitted to the front sprocket 50. On the other hand, even if the crankshaft 30 rotates in the reverse direction, the rotational force is not transmitted to the front sprocket 50. Furthermore, when the front sprocket 50 rotates in the forward direction faster than the crankshaft 30, or when only the front sprocket 50 rotates, the pawls 43 of the inner clutch 42 do not get caught in the grooves 41a of the outer clutch 41.

[0045] On the other hand, since the claws 43 of the inner bicycle 42 are biased toward the outer bicycle 41 and are in contact with the inner circumferential surface of the outer bicycle 41, when the second mode, such as a push-walking mode in which the feet are not placed on the pedals 8a, 8b, is executed, the crankshaft 30 rotates due to the rotation of the front sprocket 50, and the pedals 8a, 8b tend to rotate together. That is, when the inner bicycle 42 fixed to the front sprocket 50 rotates in the direction of arrow B in Fig. 6 with no load applied to the pedals 8a, 8b, the claws 43 of the inner bicycle 42 move in the direction of arrow C in Fig. 6, but due to the frictional force acting between the claws 43 and the inner circumferential surface of the outer bicycle 41, the crankshaft 30 tends to rotate due to the rotational force transmitted to the outer bicycle 41.

[0046] On the other hand, according to this embodiment, the weight of the left pedal side member 6a is different from that of the right pedal side member 6b, so that the rotational resistance of the crankshaft 30 acting due to the weight difference between the left pedal side member 6a and the right pedal side member 6b exceeds the rotational force transmitted from the front sprocket 50 to the crankshaft 30 via the one-way clutch 40, and stops the crankshaft 30. As a result, even if the crankshaft 30 tends to rotate via the one-way clutch 40 by the auxiliary power of the motor 12 when the second mode is executed, the rotation of the crankshaft 30 stops with the left pedal 8a lowered. That is, as shown in FIG. 9, when the left crank arm 7a rotates in the direction of arrow B due to the rotation of the crankshaft 30 and the left pedal 8a is at the lowest position, the left crank arm 7a does not rotate further in the direction of arrow B in the direction in which the left pedal 8a rises due to the weight difference between the two pedal side members 6a and 6b on the left and right. This prevents the pedals 8a, 8b from rotating together, making it easier for a user pushing or supporting the bicycle to walk alongside it.

[0047] In particular, in this embodiment, a weight difference is provided between the two left and right pedals 8a, 8b located far from the center of rotation of the crankshaft 30, which is the center of rotation of each of the crank arms 7a, 7b, so that the rotational resistance of the crankshaft 30 can be easily increased without making the weight difference excessively large. Moreover, a weight difference can be provided between the two left and right pedals 8a, 8b simply by providing a metal part 74 on the left pedal 8a, which is one of the two left and right pedals 8a, 8b. This makes it possible to easily realize the power-assisted bicycle 1 of the embodiment, in which a weight difference is provided between the two left and right pedal side members 6a, 6b, by utilizing an existing power-assisted bicycle that does not have a weight difference between the two left and right pedals.

[0048] Furthermore, since the weight of the left pedal side member 6a is greater than the weight of the right pedal side member 6b, the left pedal 8a can be kept in the lowest position during execution of the second mode, such as when pushing the bicycle while walking. Therefore, when the user stands on the left side of the bicycle and pushes it while walking, or supports the bicycle while walking, the left pedal 8a does not hit the upper side of the user's foot. Also, when the user wants to ride the bicycle, since the left pedal 8a is at the bottom, the user can easily place their foot on the left pedal 8a without having to move the left pedal 8a all the way down, making it easier to ride the bicycle.

[0049] On the other hand, unlike the embodiment, it is possible to provide a movable stopper and stop the rotation of the part that rotates integrally with the crankshaft 30 by moving the stopper, thereby suppressing the co-rotation of the pedal, but in that case, the structure may become complicated and the cost may become high. According to the embodiment, such inconvenience does not occur.

[0050] Also, unlike the embodiment, it is possible to make the weight of each pedal heavier than that of existing electric assist bicycles while keeping the weight of both left and right pedals the same, and to suppress co-rotation of the pedals by the rotational resistance of the crankshaft generated by this. However, in this case, the weight of each pedal must be made considerably large in order to generate the rotational resistance of the crankshaft that suppresses co-rotation of the pedals. In the case of the embodiment, co-rotation of the pedals 8a, 8b can be suppressed simply by making one of the two left and right pedals 8a, 8b heavier than the other, and there is no need to set the weight difference at that time to be excessively large.

[0051] In the above embodiment, a structure has been described in which, in the one-way clutch 40, the inner 42 rotates integrally with the front sprocket 50 and the outer 41 rotates integrally with the crankshaft 30, and when the crankshaft 30 rotates in the forward direction, the pawls 43 of the inner 42 get caught in the grooves 41a of the outer 41, and the rotational force in the forward direction is transmitted to the front sprocket 50. However, the configuration of the one-way clutch is not limited to this, and, for example, a structure may be used in which the outer rotates integrally with the front sprocket 50 and the inner rotates integrally with the crankshaft 30, and when the crankshaft 30 rotates in the forward direction, the pawls of the inner get caught in the grooves of the outer, and the rotational force in the forward direction is transmitted to the front sprocket 50.

[0052] FIG. 10 is a perspective view of a left pedal 75 in another embodiment, with the pedal shaft omitted. FIG. 11 is a view of the left pedal 75 as seen from above. FIG. 12 is a perspective view of a metal part 80 incorporated in the left pedal 75. In the configuration of this example, the left pedal 75 includes a pedal body 76 formed of a resin molded body 76a and having a tread surface, a pedal shaft 79 rotatably supported at the center of the pedal body 76, and the metal part 80. The pedal body 76 has a recess 78 with a substantially pentagonal cross section formed on one longitudinal side (the left side in FIG. 11) of the surface on which the tread surface 77 is located. Thin plate-like protrusions 78a are formed at multiple positions on the bottom surface of the recess 78.

[0053] As shown in FIG. 12, the metal part 80 has a substantially rectangular frame 81 and legs 82, 83, 84 with a substantially V-shaped cross section that extend outward in the width direction from multiple positions in the longitudinal direction at both ends of the frame 81. The sides of the tips of the legs 82, 83, 84 opposite the frame 81 (the lower surface in FIG. 12) are located on the same plane. A groove 80a is formed between the adjacent legs 82, 83, 84 in each of the legs 82, 83, 84 on both sides in the width direction. As shown in FIG. 10 and FIG. 11, the metal part 80 is fastened to a screw hole (not shown) of the pedal body 76 by a screw 90 in a state in which the sides of the tips of the legs 82, 83, 84 opposite the frame 81 are in contact with the bottom surface of the recess 78 of the pedal body 76. As a result, the metal part 80 is joined and fixed to the resin molded body 76a that forms the pedal body 76. At this time, the protrusion 78a protruding from the bottom surface of the recess 78 is inserted into the groove 80a of the metal part 80. In addition, the frame part 81 of the metal part 80 is disposed in a state in which it bulges outward from the tips of the legs 82, 83, and 84, and a rotation support part (not shown) of the pedal shaft 79 is disposed inside the frame part 81.

[0054] Although the right pedal is not shown, it has the same configuration as the left pedal 75, but without the metal part 80. As a result, the left pedal 75 is heavier than the right pedal by the amount of the metal part 80. In this example, the other configurations and functions are the same as those in Figs. 1 to 9.

[0055] FIG. 13 is a perspective view of a drive mechanism for the chain 60 in another embodiment. In the configuration of this example, the left crank arm 85a and the right crank arm 85b connected to both axial ends of the crankshaft 30 have different weights. Specifically, the left crank arm 85a is made of iron and the right crank arm 85b is made of aluminum, so that the two left and right crank arms 85a and 85b are formed of metals with different specific gravities. As a result, the weight of the left crank arm 85a is greater than the weight of the right crank arm 85b. Although not shown in the figure, the weights of the two left and right pedals connected to the two left and right crank arms 85a and 85b are the same. As a result, the weight of the left pedal side member 6a is greater than the weight of the right pedal side member 6b.

[0056] In the case of the configuration of this example, as in the cases of the above examples, when the second mode is executed, the rotation of the crankshaft 30 can be stopped so that the left pedal is stopped at the lowest position. This prevents the pedals from rotating together, making it easier for the user who is pushing or supporting the bicycle next to the bicycle to walk. On the other hand, in the case of this example, since the crank arms 85a, 85b are located close to the center of rotation of the crankshaft 30, it is necessary to make the weight difference between the two left and right crank arms 85a, 85b larger than the weight difference when the two left and right pedals are made to have a weight difference. In this example, the other configurations and operations are the same as those of the configurations of Figs. 1 to 9 above.

[0057] FIG. 14 is a top view of a left pedal 86a and a right pedal 86b in another embodiment. FIG. 15 is a side view of the left pedal 86a and the right pedal 86b. The left pedal 86a and the right pedal 86b have different sizes of the pedal shafts 87a and 87b that are disposed inside the pedal body 70. Specifically, the diameter d1 of the pedal shaft 87a of the left pedal 86a that is disposed inside the pedal body 70 is larger than the diameter d2 of the pedal shaft 87b of the right pedal 86b that is disposed inside the pedal body 70. The sizes and shapes of the tip ends protruding from the pedal body 70 of the two pedal shafts 87a and 87b are the same. As a result, the sizes of at least some of the corresponding parts of the two left and right pedals 86a and 86b are different, and the left pedal 86a is larger than the right pedal 86b. The two left and right pedal shafts 87a and 87b are formed of the same metal material, such as iron. The two pedal shafts 87a and 87b on the left and right have the same axial length. Therefore, the weight of the left pedal 86a is greater than the weight of the right pedal 86b. In this example, the other configurations and functions are the same as those in Figs. 1 to 9. In this example, the diameters of the parts of the pedal shafts 87a and 87b that are disposed inside the pedal body 70 are made different between the two pedals 86a and 86b on the left and right. However, the sizes of at least some of the corresponding parts may be made different by making the axial lengths different instead of the diameters. In addition, the two pedal shafts 87a and 87b may be made different in overall size, including the tip parts that protrude from the pedal body 70.

[0058] FIG. 16 is a top view of the left pedal 88 in another embodiment. FIG. 17 is a side view of the left pedal 88. In the configuration of this example, inside the resin molded body 70a forming the pedal body 70 of the left pedal 88, plate-shaped metal parts 89 made of iron or the like are incorporated by insert molding or the like at both ends in the width direction (the vertical direction in FIG. 16). On the other hand, although not shown, the right pedal has a similar configuration to the left pedal 88 except that the plate-shaped metal part 89 is not included. The plate-shaped metal part 89 may be made of a retroreflective material or a light-emitting material. This makes the weight of the left pedal 88 greater than that of the right pedal. In this example, the other configurations and functions are the same as those of FIGS. 1 to 9.

[0059] In the above examples, the weight of the left pedal or left crank arm is made greater than that of the right pedal or right crank arm, so that the weight of the left pedal side member is made greater than that of the right pedal side member. On the other hand, the weight of the right pedal or right crank arm may be made greater than that of the left pedal or left crank arm, so that the weight of the right pedal side member is made greater than that of the left pedal side member. In this case, the right pedal can be kept in the lowest position during execution of the second mode, such as when pushing the bicycle. Therefore, when the user stands on the right side of the bicycle and walks, the right pedal does not hit the upper side of the user's foot. In addition, when the user tries to ride the bicycle, since the right pedal is at the bottom, the user can easily place his / her foot on the right pedal without moving the right pedal to the bottom, making it easier to ride the bicycle. Whether to make the left pedal side member or the right pedal side member heavier can be appropriately set depending on which side of the bicycle the user finds easier to ride.

[0060] In addition, in each of the above examples, the pedal bodies of the left and right pedals are described as being formed from a resin molded body, but the configuration of the present disclosure is not limited to this, and for example, the pedal body of each pedal or the entire pedal may be formed from a metal such as an aluminum alloy. [Explanation of symbols]

[0061] 1 Electrically assisted bicycle, 2 Frame, 2a Head pipe, 2b Front fork, 2c Down pipe, 2d Seat pipe, 2e Chain stay, 2f Seat stay, 3a Front wheel, 3b Rear wheel, 4 Handle, 5 Saddle, 6a Left pedal side member, 6b Right pedal side member, 7a Left crank arm, 7b Right crank arm, 8a Left pedal, 8b Right pedal, 9 Headlight, 10 Battery, 11 Motor unit, 12 Motor, 13 Drive circuit, 14 Torque sensor, 15 Vehicle speed sensor, 16 Rotation sensor, 17 Power switch, 18 Second mode switch, 20 Control device, 21 Processor, 22 Memory, 23 First mode execution processing unit, 24 Second mode execution processing unit, 30 Crankshaft, 31 Cylindrical body, 33 Bearing, 40 One-way clutch, 41 Outer, 41a Groove, 42 Inner, 43 Claw, 50 front sprocket, 60 chain, 61 rear sprocket, 62 second sprocket, 63 chain case, 64 unit case, 70 pedal body, 70a resin molded body, 71 through hole, 72 pedal shaft, 74 metal part, 75 left pedal, 76 pedal body, 76a resin molded body, 77 tread surface, 78 recess, 78a protrusion, 79 pedal shaft, 80 metal part, 80a groove, 81 frame portion, 82, 83, 84 leg portion, 85a left crank arm, 85b right crank arm, 86a left pedal, 86b right pedal, 87a, 87b pedal shaft, 88 left pedal, 89 metal part, 90 screw.

Claims

1. The torque of the crankshaft, which is rotated by the human driving force generated by the left and right pedals, is transmitted to the wheel side via a one-way clutch. An electrically assisted bicycle that can output auxiliary power from a motor to the wheel side to push the bicycle or to propel the bicycle itself. the left pedal and the right pedal each include a resin molded body, and only one of the left pedal and the right pedal has a metal part for creating a predetermined weight difference; The resin molded body has a tread surface and a recess formed in a part of the tread surface, The metal part is fixed to the resin molded body in a state of contacting a bottom surface of the recess. Electrically assisted bicycle.

2. The torque of the crankshaft, which is rotated by the human driving force generated by the left and right pedals, is transmitted to the wheel side via a one-way clutch. An electrically assisted bicycle that can output auxiliary power from a motor to the wheel side to push the bicycle or to propel the bicycle itself. the left pedal and the right pedal each include a resin molded body, and only one of the left pedal and the right pedal has a metal part for creating a predetermined weight difference; When the one pedal is attached to the electric-assisted bicycle, the resin molded body has a tread surface and a first through hole formed so as to penetrate the resin molded body in a thickness direction, The metal component has a second through hole at a position aligned with the first through hole in the thickness direction. Electrically assisted bicycle.

3. The torque of the crankshaft, which is rotated by the human driving force generated by the left and right pedals, is transmitted to the wheel side via a one-way clutch. An electrically assisted bicycle that can output auxiliary power from a motor to the wheel side to push the bicycle or to propel the bicycle itself. The left pedal and the right pedal have different weights, The left pedal and the right pedal have different sizes of at least a part of a corresponding portion of a pedal shaft. Electrically assisted bicycle.

4. The electrically assisted bicycle according to any one of claims 1 to 3, The weight difference between the left pedal and the right pedal is 50 g to 500 g. Electrically assisted bicycle.

5. The electrically assisted bicycle according to claim 1, The metal part includes a plurality of legs and a groove formed between the plurality of legs, A plate-shaped rib protruding from a bottom surface of the recess of the resin molding toward the tread surface side is inserted into the groove. Electrically assisted bicycle.

Images