JP5312141B2 - Bicycle with vehicle treading force detection device and auxiliary power device - Google Patents

Description

  The present invention relates to a vehicle treading force detection device and a bicycle with an auxiliary power unit, and in particular, when transmitting a treading force to a driving wheel, to enhance a feeling (direct feeling) that the treading force is directly transmitted to the driving wheel without time delay. The present invention relates to a preferred vehicle pedaling force detection device and a bicycle with an auxiliary power device equipped with the pedaling force detection device.

  2. Description of the Related Art A power assist type bicycle or a bicycle with an auxiliary power device is known in which a reaction force (stepping force) when a bicycle pedal is depressed is detected and auxiliary power corresponding to the detected pedaling force is generated by a motor. Various pedaling force detection devices employed in such bicycles are known. For example, the pedaling force detection device described in Patent Document 1 is a torsion bar connected to a crankshaft when the pedaling force is applied to the crankshaft. Is a torsion caused by a difference in force generated between the input side and the output side (sprocket side), and the torsion is converted into a displacement in the crankshaft direction by a cam mechanism, and this displacement is detected by a stroke detection device. .

Patent Publication No. 2906023

  As described in Japanese Patent Application Laid-Open No. H10-228867, in a treading force detection device using a torsion bar, the torsion bar is twisted when the crank pedal is depressed, and this twist acts as a lost motion mechanism. Therefore, when pedal force is applied, auxiliary power is generated and transmitted to the drive wheels after a time delay due to lost motion, so there is a subtle difference between when the user applies pedal force and when the auxiliary power is transmitted to the drive wheels. There was a problem that a slight time lag occurred and it was difficult to obtain a direct feeling.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and a pedal force detection device for a vehicle and a bicycle with an auxiliary power device capable of transmitting auxiliary power to a drive wheel without time delay with respect to the pedal force applied to the pedal. Is to provide.

  In order to achieve the above object, the present invention provides a pedal force detection device for a vehicle having a drive sprocket that is rotated by a pedal force applied to a crankshaft through a pedal, and a transmission that transmits the rotation of the drive sprocket to a drive wheel. A cam mechanism that is provided between the crankshaft and the drive sprocket and that displaces the positional relationship between the crankshaft and the drive sprocket in accordance with a load applied to the drive sprocket, and is displaced by the displacement generated by the cam mechanism. A first feature is that it includes a hydraulic piston and a hydraulic sensor that detects the hydraulic pressure of the incompressible oil in the oil passage caused by the displacement of the hydraulic piston.

  In addition, the present invention has a second feature in that the hydraulic piston is disposed concentrically with the crankshaft so as to be displaced in the axial direction of the crankshaft by the cam mechanism.

  Further, the present invention has a third feature in that a check valve for discharging air bubbles mixed in the incompressible oil in the oil passage is connected to the oil passage.

  In addition, the present invention is characterized in that the check valve functions as a relief valve for releasing the incompressible oil to an oil reservoir when the hydraulic pressure of the incompressible oil in the oil passage becomes a predetermined value or more. There are features.

  Further, the present invention has a fifth feature in that the hydraulic sensor is provided below the oil sump.

  Further, according to the present invention, the drive sprocket is a pair of disk-shaped members provided with a sprocket outer ring having sprocket teeth, and a slidable contact with both side surfaces of the sprocket outer ring fixed to the crankshaft. A cover member, a hydraulic piston housed in a hub of the disc-shaped cover member, and provided to be displaceable in an axial direction of the crankshaft; and a displacement of the sprocket outer ring in a radial direction with respect to the crankshaft. A hydraulic mechanism that detects the hydraulic pressure of the incompressible oil in the oil passage that is generated by the displacement of the hydraulic piston, and includes a cam mechanism that transmits the hydraulic piston to an axial displacement of the crankshaft. There is a sixth feature in that it is provided.

  Further, in the present invention, the oil passage is formed so as to communicate the space in the hub in which the hydraulic piston is accommodated with the hydraulic sensor through an oil passage portion formed in the crankshaft. The point has the seventh feature.

  Furthermore, the present invention is a vehicle with an auxiliary power device provided with a motor that provides auxiliary power to the drive wheels according to the pedal force represented by the detection signal of the hydraulic sensor of the pedal force detection device having the above characteristics. There is an eighth feature.

  According to the present invention having the first to eighth features, the cam mechanism is operated by the pedaling force corresponding to the load applied to the drive sprocket, the hydraulic piston is displaced via the cam mechanism according to the magnitude of the pedaling force, and the oil The pressure in the road changes. The oil pressure detected by the oil pressure sensor represents the pedaling force. In this way, the cam mechanism is moved according to the pedaling force, and the displacement is detected as the hydraulic pressure of the incompressible oil, so that the displacement of the relative position between the drive sprocket and the crankshaft is directly transmitted to the hydraulic piston. There is no loss of direct feeling when is transmitted to the drive wheels.

  According to the second feature, since the hydraulic piston is disposed concentrically with the crankshaft, the pedaling force detection device can be compactly assembled around the crankshaft.

  According to the 3rd characteristic, the bubble mixed in the oil path is discharged | emitted, and the incompressible fall of the oil by bubble biting can be prevented.

  According to the fourth feature, it is possible to prevent the hydraulic pressure from becoming too high.

  According to the fifth feature, when air is mixed into the oil, the air tends to move to the upper oil reservoir side and be discharged without going to the hydraulic pressure sensor side.

  According to the present invention having the sixth and seventh characteristics, the tension on the tension side of the drive chain changes according to the magnitude of the pedaling force. Due to this change in tension, a force is generated that the sprocket outer ring tends to displace relative to the hub, and the cam mechanism acts to displace the hydraulic piston in the axial direction of the crankshaft. The pedal force can be detected by detecting a change in the oil pressure in the oil passage due to the displacement of the hydraulic piston with a hydraulic sensor.

  According to the sixth and seventh features, since a hydraulic device is used, the direct feeling when the pedaling force is transmitted to the drive wheel is not impaired, and a hydraulic piston is arranged in the center of the drive sprocket, that is, in the hub. Since the cam mechanism is provided in the drive sprocket, the arrangement space is not increased.

  According to the eighth feature, the pedaling force can be transmitted to the rear wheel while maintaining a direct feeling, and the motor can be driven according to the detected pedaling force to reduce the pedaling force, so that the bicycle can be run lightly. .

It is sectional drawing of the treading force detection apparatus which concerns on one Embodiment of this invention. 1 is a left side view of a bicycle with an auxiliary power device including a pedaling force detection device according to an embodiment of the present invention. It is sectional drawing of the power unit of the bicycle which concerns on one Embodiment of this invention. It is principal part side surface sectional drawing of the power unit which shows a pedaling force detection apparatus. It is principal part sectional drawing of the driven part provided around the axis | shaft of the rear-wheel of a bicycle. It is sectional drawing which shows the structure of the cam which connects the hub of a sprocket, and a treading force detection apparatus. It is a left view of the bicycle with an auxiliary power device carrying the treading force detection device concerning a 2nd embodiment. It is sectional drawing of the treading force detection apparatus which concerns on 2nd Embodiment. It is a side view of a manpower drive sprocket of a bicycle with an auxiliary power unit. It is sectional drawing which shows the oil circuit which concerns on 2nd Embodiment.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a left side view of a bicycle with an auxiliary power device provided with a pedaling force detection device according to an embodiment of the present invention. In FIG. 1, a body frame of a bicycle 1 is a head pipe 2 and a pair of mains that extend downward and rearward (right direction in FIG. 2) from the head pipe 2 and are respectively displaced to the outside in the vehicle width direction. A frame 3, a main frame 3 and a seat pipe 4 supported on the rear portion of the main frame 3 and extending upward; a rear frame (not shown) joined to the rear portion of the main frame 3 and extending rearward; The rear frame includes a rear frame and a sub-frame 5 having both ends connected to the seat pipe 4.

  A steering shaft 6 extends vertically through the head pipe 2, a steering handle 7 is attached to the top of the steering shaft 6, and the front of the steering shaft 6 branches to the left and right in the vehicle width direction. A fork 8 is attached. A front wheel 10 supported by a front axle 9 is provided at the lower end of the front fork 8.

  The power unit 11 is disposed from the center of the body frame, that is, from the joint between the main frame 3 and the seat pipe 4 to the rear position. The power unit 11 includes a crankshaft 12 extending in the vehicle width direction, a motor 13 disposed behind the crankshaft 12, a chain 49 that transmits the rotation of the crankshaft 12 to the rear wheel 14, and the rotation of the motor 13. The chain 50 transmits the generated power to the rear wheel 14. A driver 16 of the motor 13 is disposed above the power unit 11 and below the subframe 5. A crank 12a is connected to the crankshaft 12, and a pedal 12b is attached to the end of the crank 12a.

  In a space formed between the pair of left and right main frames 3, a battery 17 composed of a large number of cells is provided. A battery charger 18 for the battery 17 is provided behind the battery 17. The battery 17 can be charged with commercial power by connecting the charger 18 to a commercial power source. The upper and lower sides of the main frame 3 are covered with a cover member (not shown), and the battery 17 can be attached and detached through an openable / closable lid 19 provided on the upper part of the main frame 3.

  A headlight 20 and a blinker 21 are attached in front of the head pipe 2. On the other hand, a taillight 23 is attached to a rear fender 22 that covers the upper part of the rear wheel 14 at the rear of the vehicle body. A rear winker 24 is attached to the subframe 5. The seat pipe 4 is fitted with a seat post 26 that supports the seat 25 on the top.

  FIG. 3 is a cross-sectional view of the power unit 11, and FIG. 4 is a side cross-sectional view of the main part of the power unit 11 showing the pedaling force detection device. 3, the vertical direction is the front-rear direction of the bicycle 1, and the left-right direction is the front-rear direction of the bicycle 1 in FIG. 4. The casing 27 of the power unit 11 includes a vehicle body right side portion (right case) 271, a vehicle body left side portion (left case) 272, and an intermediate portion (intermediate case) 273. The crankshaft 12 is rotatably supported at the front portion of the casing 27 by a right bearing 28 fitted into the right case 271 and a left bearing 29 fitted into the left case 272. Although the inner ring of the right bearing 28 is in direct contact with the outer peripheral surface of the crankshaft 12, the left bearing 29 is connected to the crankshaft via a hub 30 and a sleeve 31 interposed between the inner ring and the outer peripheral surface of the crankshaft 12. 12 is supported.

  A manually driven sprocket 32 is coupled to the hub 30. On the right side of the hub 30, a hydraulic pressure transmission device 33 that constitutes the pedaling force detection device 100 together with the hub 30 is disposed. Details of the pedaling force detection device 100 and the hydraulic transmission device 33 will be described later.

  The motor 13 as an auxiliary power source is an outer rotor type brushless motor, and the rotor 34 includes a rotor shaft 37 supported at both ends by a bearing 35 fitted in the right case 271 and a bearing 36 fitted in the left case 272. The rotor shaft 37 is composed of an outer core 38 in which a boss portion is splined. The stator 39 includes a stator core 40 and a coil 41 wound around the stator core 40, and is fixed to the intermediate case 273 with bolts 42. A plurality of magnets 43 facing the outer periphery of the stator core 40 are arranged on the inner periphery of the rotor 34.

A pinion 371 is formed on the rotor shaft 37 near the bearing 36, and an output shaft 45 coupled with a reduction gear 44 that meshes with the pinion 371 is fitted into the bearing 46 fitted into the intermediate case 273 and the left case 272. The bearing 47 is supported.
A motor driven sprocket 48 is coupled to the output shaft 45.

  A manpower transmission chain 49 is hung on the manpower driven sprocket 32, and a motor power transmission chain 50 is hung on the motor driven sprocket 48.

  In FIG. 4, the oil reservoir 51 and the hydraulic sensor 52 of the pedal effort detection device 100 are arranged radially from the central axis of the crankshaft 12 along the shape of the front end portion (front side of the vehicle body) of the left case 272. The hydraulic sensor 52 is disposed below the reservoir 51 with the crankshaft 12 interposed therebetween. One side surface of the reservoir 51 is in contact with the inner surface of the left case 272, while the other side surface of the reservoir 51 is in contact with a boss 53 erected on the right case 272. Thereby, the position of the pedaling force detection device 100 around the axis of the crankshaft 12 is determined.

  FIG. 5 is a cross-sectional view of the main part of the driven portion provided around the axis of the rear wheel 14. The rear wheel shaft 54 supports the hub 55 on the rear wheel shaft 54 by a left side bearing 56 provided on the left side of the hub 55 of the rear wheel 14 and a right side bearing (not shown). A manpower driven sprocket 57 and a motor driven sprocket 58 are supported on a portion protruding leftward from the hub 55. A collar 59 is fixed to the rear wheel shaft 54, and one-way clutches 61 and 62 are provided on the outer periphery of the collar 59 via a needle bearing 60. An outer 57 a to which a manpower driven sprocket 57 is fixed is provided on the outer periphery of the one-way clutch 61, and a motor driven sprocket 58 is provided on the outer periphery of the one-way clutch 62. The one-way clutch 61 is a ratchet type, and the one-way clutch 62 is a ball type (a structure in which a ball fits into a tapered groove formed between an outer ring and an inner ring to couple the outer ring and the inner ring. ). A common inner ring 63 of the one-way clutches 61 and 62 is connected to the hub 55. The one-way clutches 61 and 62 are set so that the outer ring and the inner ring 63 are coupled in the direction in which the bicycle 1 is advanced.

  In the power unit 11 having the above-described configuration, when the crankshaft 12 is rotated by human power (stepping force), the human-powered sprocket 32 rotates and the pedaling force is transmitted to the human-powered sprocket 57 via the human power transmission chain 49. This pedaling force is transmitted to the hub 55 via the one-way clutch 61 and the inner ring 63, and the rear wheel shaft 51 is rotated. On the other hand, according to the pedaling force detected by the pedaling force detection device 100, the driver 16 (see FIG. 2) is controlled so that a larger current flows through the motor 13 as the pedaling force increases, and the motor 13 is rotated by the supplied current. To do. The rotation of the motor 13 is transmitted to the motor drive sprocket 48 via the pinion 371 and the reduction gear 44. The rotation of the motor 13 is further transmitted to the motor driven sprocket 58 by the motor transmission chain 50. The rotation of the motor is further transmitted to the hub 55 via the one-way clutch 62 and the inner ring 63, and the rear wheel shaft 51 is rotated.

  FIG. 1 is a cross-sectional view of the pedaling force detection device 100, and FIG. 6 is a cross-sectional view showing the structure of a torque cam, that is, a cam that connects the hub 30 of the sprocket 32 and the torque detection device 100. 1 and 6, a sleeve 65 is fitted on the outer periphery of the crankshaft 12, and the hub 30 of the sprocket 32 is slidably fitted on the outer periphery on the left side of the sleeve 65 in the figure. A spline 66 is formed on the outer periphery of the right portion of the sleeve 65, and a cam ring 67 and a pressing ring 68 are engaged with the spline 66.

  As shown in FIG. 6, recesses 70 and 71 into which the steel balls 69 are fitted are formed on the opposing surfaces of the cam ring 67 and the right end of the hub 30. The recesses 70 and 71 have a partial spherical surface having the same shape as the outer periphery of the steel ball 69, and have a surface f that extends away from the partial spherical surface having the same shape as the steel ball 69 in the vicinity of the edge. . When a relative force acts between the cam ring 67 and the hub 30 as indicated by an arrow A, the positions of the cam ring 67 and the hub 30 are shifted, and the edge surfaces of the cam ring 67 and the recesses 70 and 71 of the hub 30 are steel balls 69. Get on. As a result, the cam ring 67 and the hub 30 are displaced in the direction of arrow B.

  An oil reservoir 51 and a pressure sensor 52 are disposed between the cam ring 67 and the pressing ring 68. A thrust needle bearing 74 is disposed between the right side surface of the case 72 of the oil reservoir 51 and the case 73 of the pressure sensor 52 and the pressing ring 68. On the other hand, an annular groove 75 disposed concentrically with the crankshaft 12 is formed on the left side surfaces of the oil reservoir 51 and the pressure sensor 52. The bottom (right side in the figure) of the annular groove 75 communicates with the oil reservoir 51a of the oil reservoir 51 via a check valve 76 having a check ball 76a. The check valve 76 is shown in a simplified manner, and a more specific structure will be described in detail with respect to FIG. The bottom of the annular groove 75 communicates with the pressure detection space 52a of the pressure sensor 52 at another position.

  An annular disc spring 77 is disposed at the bottom of the annular groove 75, and a hydraulic piston 78 formed of an annular plate is provided in the annular groove 75 via the disc spring 77. The hydraulic piston 78 and the annular groove 75 are sealed with O-rings 79 and 80. A thrust needle bearing 81 is also provided between the hydraulic piston 78 and the cam ring 67.

  A cap 82 is put on the outside of the pressing ring 68, that is, on the right side in the figure, and the position is regulated by the stop ring 83. That is, the hydraulic piston 78 is biased toward the cam ring 67 by the disc spring 77.

  In this configuration, when the crankshaft 12 is rotated by stepping on the pedal 12b, the sleeve 65 rotates. When the sleeve 65 is rotated, the cam ring 67 and the pressing ring 68 are rotated. At this time, since a load is applied to the hub 30 coupled to the sprocket 32, a positional shift in the rotational direction of the crankshaft 12 occurs between the cam ring 67 and the hub 30. The amount of displacement of this position corresponds to the load applied to the sprocket 32, that is, the hub 30, that is, the pedaling force. Then, due to the displacement according to the load, the cam ring 67 or the edge surface of the recesses 70 and 71 of the hub 30 rides on the steel ball 69, and the cam ring 67 and the hub 30 move away from each other (B in FIG. 6). Direction). Since the position of the hub 30 in the longitudinal direction of the crankshaft 12 is fixed, the cam ring 67 is displaced.

  The cam ring 67 displaces the hydraulic piston 78 to the right side in the figure via the thrust needle bearing 81. Due to the displacement of the hydraulic piston 78, pressure is applied to the incompressible oil existing in the annular groove 75, the space between the annular groove 75 and the check ball 76 a, and the pressure detection space 52 a of the hydraulic sensor 52. 52 detects the pressure. The greater the load on the sprocket 32, the greater the displacement of the cam ring 67, and the greater the pressure value detected by the hydraulic sensor 52. That is, the hydraulic pressure sensor 52 indicates a higher pressure value as the pedaling force increases in accordance with the pedaling force applied to the pedal 12.

  Since the oil that operates the hydraulic sensor 52 is incompressible, the displacement of the cam ring 67 is transmitted to the hydraulic sensor 52 with a good direct feeling and can contribute to the detection of the pedaling force.

  Next, a second embodiment of the present invention will be described. FIG. 7 is a left side view of a bicycle with an auxiliary power device equipped with a pedaling force detection device according to the second embodiment, and the same reference numerals as those in FIG. 2 denote the same or equivalent parts. In FIG. 7, only one main frame 3 a extends downward and rearward from the head pipe 2. Therefore, the battery 17 is not housed between the main frames 3 and 3 as in the first embodiment, but is supported forward with respect to the seat pipe 4.

  FIG. 8 is a cross-sectional view of a pedaling force detection device according to the second embodiment, and FIG. 9 is a side view of a human-powered sprocket. FIG. 9 shows a state where the cover on one side is removed. 8 and 9, a cylindrical bearing case (hub) 84 is joined to the main frame 3a. The hub 84 is provided with bearings 85 and 86 at both ends, respectively. Thus, the crankshaft 12 is supported. An oil seal 88 held by a holding member 87 is provided on the inner peripheral surface of the hub 84. The oil seal 88 is a pair of two, and oil can flow between them.

  A manpower driven sprocket 32 is fixed to the crankshaft 12. The human-powered sprocket 32 has a first cover member 90 having a spline engaging with a spline 89 formed on the outer periphery of the crankshaft 12 on the inner peripheral surface of the hub 90a and a second cover member 90 combined with the first cover member 90. Cover member 91. Both the first cover member 90 and the second cover member 91 are disk-shaped.

  An annular piston 92 is accommodated in the hub 90 a of the first cover member 90, and the piston 92 is urged to the right side in the drawing by a disc spring 93. The piston 92 biased by the disc spring 93 has an inclined surface (cam surface) 94 on the right end surface, and a plate 95 is disposed on the right side of the piston 92 having the cam surface 94. A steel ball 96 is disposed between the plate 95 and the cam surface 94, and a plurality of (three in this case) push rods 97 extending radially from the steel ball 96 to the sprocket 32 are provided. The push rods 97 are respectively supported by a pair of cylindrical pieces 98 and are accommodated between the first cover member 90 and the second cover member 91. The piece 98 is formed to protrude from at least one of the opposing surfaces of the first and second cover members 90 and 91.

  One end surface of the push rod 97 is in contact with the steel ball 96, and the other end, that is, the tip portion is in contact with a cam surface (concave portion) 99 a formed on the inner periphery of the sprocket outer ring 99. Both side surfaces of the sprocket outer ring 99 face portions in the vicinity of the outer peripheral portions of the first and second cover members 90 and 91, and are slidably held with respect to the first and second cover members 90 and 91. ing.

  An oil passage 101 communicating with an oil reservoir described later is formed in the crankshaft 12, and the oil passage 101 has a branch pipe 102 that extends into a space in which the disc spring 93 is accommodated. The oil passage 101 further includes a hydraulic pressure detection passage 104 that passes between the oil seals 88 and extends from the holding member 87 to the boss 103 that protrudes outside the hub 84. A hydraulic sensor 52 is attached to the boss 103 to detect the pressure of the incompressible oil introduced through the hydraulic pressure detection conduit 104. O-rings 105, 106, 107, and 108 are disposed between the inner and outer circumferences of the piston 92 and between the first cover member 90 and the crankshaft 12.

  FIG. 10 is a cross-sectional view showing an oil circuit according to the second embodiment, and the same reference numerals as those in FIG. 8 denote the same parts. The boss 103 protruding from the holding member 87 to the outside of the hub 84 is provided with the hydraulic sensor 52 described above, and an oil having an oil supply line 109 in a direction perpendicular to the hydraulic sensor 52 on the side of the boss 103. A reservoir 51 is provided.

  The oil reservoir 51 is the same as that of the first embodiment, and includes an oil reservoir 51 a and a check valve 76. The check valve 76 includes a check ball 76a, a check ball seat 76b having a seating surface facing the upper surface of the check ball 76a, and a check ball seat spring 76c for pressing and urging the check ball sheet 76b against the check ball 76a. Consists of.

  The check valve 76 prevents the oil from flowing backward from the oil passage to the oil reservoir 51a. However, when the pressure in the oil passage becomes higher than a predetermined value, the check ball seat 76b is displaced upward, A relief function for returning the oil to the oil reservoir 51a is achieved. The check valve 76 also functions as an air vent for discharging bubbles generated in the oil to the oil reservoir 51a during initial assembly of the pedal force detection device.

With the above configuration, when the crankshaft 12 is rotated by stepping on the pedal 12b, the manpower driven sprocket 32 rotates. At this time, when the chain 49 is pulled by the sprocket 32, the push rod 97 is displaced toward the central portion (hub) 90a of the manpower driven sprocket 32 by the concave portion inside the sprocket outer ring 99, that is, the cam surface 99a. Then, the push rod 97 is pushed to the steel ball 96 side, and the piston 92 is displaced in the left direction in FIG. 8 by the wedge action of the steel 96 that bites between the cam surface 94 and the plate 95. The pressure on the oil changes. This pressure is detected by the hydraulic sensor 52 through the hydraulic pressure detection pipe 104. The displacement amount of the piston 92, that is, the magnitude of the oil pressure corresponds to the magnitude of the pedaling force applied to the push rod 97.
As described above, in the first and second embodiments of the present invention, the pedaling force is converted into the displacement of the piston that applies pressure to the incompressible oil, so that the pedaling force change can be directly performed without lost motion. The motor 13 can be driven according to the pedaling force to assist the driving force of the bicycle 1 with an auxiliary power device.

  DESCRIPTION OF SYMBOLS 1 ... Bicycle, 2 ... Head pipe, 3 ... Main frame, 11 ... Power unit, 12 ... Crankshaft, 13 ... Motor, 16 ... Driver, 17 ... Battery, 19 ... Lid, 30 ... Hub, 32 ... Human power drive sprocket, 33 ... hydraulic voltage device, 48 ... motor driven sprocket, 49 ... human power driven chain, 50 ... motor driven chain, 51 ... oil reservoir, 52 ... hydraulic sensor, 67 ... cam ring, 69 ... steel ball, 78, 92 ... piston, 97 ... Push rod, 99 ... Sprocket outer ring, 100 ... Treading force detection device

Claims (3)

Treading force of a vehicle having a drive sprocket (32) rotated by a pedaling force applied to the crankshaft (12) through the pedal (12b) and a transmission device for transmitting the rotation of the driving sprocket (32) to the driving wheels (14) In the detection device,
The drive sprocket (32)
A sprocket outer ring (99) having sprocket teeth;
A pair of disc-like cover members (90, 91) fixed to the crankshaft (12) and provided slidably in contact with both side surfaces of the sprocket outer ring (99);
A hydraulic piston (92) housed in the hub (90a) of the disc-like cover member (90, 91) and provided to be displaceable in the axial direction of the crankshaft (12);
A cam that transmits the displacement of the sprocket outer ring (99) in the radial direction with respect to the crankshaft (12) to the hydraulic piston (92) and converts the hydraulic piston into an axial displacement of the crankshaft (12). Mechanism (97, 96),
A vehicle treading force detection device comprising a hydraulic pressure sensor (52) for detecting a hydraulic pressure of incompressible oil in an oil passage caused by displacement of the hydraulic piston (92). The oil passage communicates the space in the hub (90a) in which the hydraulic piston (92) is accommodated with the hydraulic sensor (52) via an oil passage portion formed in the crankshaft (12). The vehicle treading force detection device according to claim 1 , wherein the stepping force detection device for a vehicle is formed as described above. A motor (13) for providing auxiliary power to the drive wheels (14) according to a pedaling force represented by a detection signal by a hydraulic sensor of the pedaling force detection device according to any one of claims 1 to 2 is provided. Bicycle with an auxiliary power device.

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