JP2014231234A - Power-assisted bicycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power-assisted bicycle including a single axis motor drive unit capable of detecting a rotation state of a crankshaft with high accuracy (with high resolution), and capable of maintaining detection capability of torque successfully.SOLUTION: In a so-called single axis motor drive unit, at a speed reduction mechanism 25 provided at a transmission path for an auxiliary driving force over a motor 21 and a resultant force body 29, a rotor 11 rotated being interlocked with a crankshaft 7a at a rotational frequency larger than that of the crankshaft 7a is disposed, and a rotation detector 10 for detecting the rotation of the rotor 11 is disposed at a control unit 24. Thereby, a rotation state of the crankshaft 7a can be detected at higher accuracy (higher resolution) than the case where the rotation is detected by mounting the rotor on the crankshaft 7a or a human power transmission body 28.

Description

  The present invention relates to an electrically assisted bicycle capable of traveling by adding an auxiliary driving force generated by a motor to a human driving force generated by a pedaling force from a pedal.

  By having a motor powered from a battery or other power storage device, detecting a human power driving force consisting of a pedaling force applied to the pedal by a torque sensor, and adding a motor auxiliary driving force (assist power) corresponding to the human power driving force, There are already known electrically assisted bicycles that can easily travel uphill.

  In some of these electric assist bicycles, a motor drive unit with a built-in motor or the like is disposed at a place where a crankshaft is provided. In the electrically assisted bicycle having such an arrangement, the motor drive unit having a relatively large weight is disposed at a low position in the center in the front-rear direction of the electrically assisted bicycle (that is, between the front wheel and the rear wheel). Therefore, the electrically assisted bicycle with this arrangement is easier to lift the front and rear wheels and has a step on the road than a motor built in the front wheel hub or rear wheel hub. The vehicle body is easy to handle and the running stability is also good.

  As shown in FIG. 12, the motor drive unit provided in this type of electric assist bicycle is roughly divided into a drive sprocket (front wheel) as a manpower driving force output wheel disposed near one end of the crankshaft 101. In addition to 102 (also referred to as a sprocket or a large gear), a motor drive unit 100 also referred to as a so-called two-shaft type equipped with an auxiliary drive force output sprocket 103 that outputs an auxiliary drive force from a motor, and FIGS. As shown in FIG. 3, the motor driving unit 200 called a so-called single-shaft type in which the human driving force by the treading force and the auxiliary driving force by the motor are combined inside the motor driving unit 200 and the combined resultant force is output from the driving sprocket 201. There is.

  The biaxial motor driving unit 100 is disclosed in, for example, Patent Document 1 and the like, and as shown in FIG. 12, the auxiliary driving force output sprocket 103 is located behind the driving sprocket 102 in the motor driving unit 100. The motor drive unit 100 is disposed so as to protrude outward from the unit case 104. Each of the driving sprocket 102 for outputting the human driving force and the auxiliary driving force output sprocket 103 for outputting the auxiliary driving force are engaged with a chain 105 as an endless driving force transmitting body. Human power driving force and auxiliary driving force are combined and transmitted to the rear wheel side.

  A tensioner device (also referred to as a guide device) 106 that engages with the chain 105 after meshing with the auxiliary driving force output sprocket 103 and guides it downward is disposed further rearward of the auxiliary driving force output sprocket 103. The tension angle of the chain 105 that meshes with the auxiliary driving force output sprocket 103 is increased by a tension sprocket 107 provided in the tensioner device 106.

  On the other hand, a so-called single-shaft motor drive unit 200 is disclosed in, for example, Patent Document 2 and the like, and as shown in FIGS. 13 and 14, on the outer periphery of the crankshaft 202 to which the manual driving force from the pedal is transmitted, A cylindrical human power transmission body 203 to which the human power driving force is transmitted by serration coupling or the like, and a resultant power body in which the human power driving force transmitted through the human power transmission body 203 and the auxiliary driving force from the motor 204 are combined. 205. And it is comprised so that the manpower driving force from the manpower transmission body 203 may be transmitted to the resultant force body 205 via the one-way clutch 206. Further, a large-diameter gear portion 205 a to which auxiliary driving force from the motor 204 is transmitted via the speed reduction mechanism 207 is formed at one end portion of the resultant force body 205, and endless drive is provided at the other end portion of the resultant force body 205. A driving sprocket 201 is attached as a driving force output wheel that meshes with a chain 208 as a force transmission body. The resultant force synthesized in the resultant force body 205 is transmitted from the drive sprocket 201 to the rear wheel side via the chain 208.

  As shown in FIGS. 13 and 14, the single-shaft motor drive unit 200 is a system in which only the drive sprocket 201 is engaged with the chain 208 and the resultant force obtained by combining the human drive force and the auxiliary drive force is transmitted to the chain 208. is there. On the other hand, as shown in FIG. 12, the biaxial motor drive unit 100 includes a drive sprocket 102 that transmits a manual driving force to a chain 105, and an auxiliary drive force output sprocket 103 that transmits an auxiliary drive force. Further, it is necessary to mesh with the tension sprocket 107.

  For this reason, the uniaxial motor drive unit 200 devise the arrangement of the motor 204, the speed reduction mechanism 207, etc., so that the area of the motor drive unit 200 as viewed from the side (projected area from the lateral direction) There is an advantage that it can be made smaller (compact) than the area of the shaft type motor drive unit 100. When a so-called front transmission is to be mounted, the single-shaft motor drive unit 200 can be easily mounted by making the drive sprocket 201 multistage. On the other hand, in the biaxial motor drive unit 100, it is necessary to mesh the drive sprocket 102, the auxiliary driving force output sprocket 103, and the tension sprocket 107 with the chain 105, so it is difficult to mount the front transmission.

  Further, the single-shaft motor drive unit 200 has an advantage that it is not necessary to provide the tensioner device 106 such as the tension sprocket 107. In addition, as a brake device used for an electric assist bicycle, a rim brake, a band brake, or a roller brake that is braked by operating a brake lever attached to a handle is often used like a general bicycle. Depending on the region or the driver's request, it may be desirable to attach a coaster brake to the rear wheel that is braked by rotating the pedal in the direction opposite to the direction of rotation during forward travel. In this case, when the pedal is rotated in the reverse direction, a tension that pulls the lower part of the chain forward acts, so the biaxial motor drive unit 100 has a special device as the tensioner device 106. Necessary. On the other hand, the single-shaft motor drive unit 200 has an advantage that no special device is required.

  By the way, in the uniaxial motor driving unit 200 having such advantages, magnetostriction for detecting the manpower driving force is detected on the outer peripheral surface of the manpower transmitting body 203 to which the manpower driving force from the crankshaft 202 is transmitted and the opposite portion thereof. A torque sensor 209 of the type is often provided. That is, a magnetostriction generation unit 209b is formed on the outer peripheral surface of the human power transmission body 203, and a coil 209a for detecting a magnetic variation in the magnetostriction generation unit 209b is disposed so as to face the magnetostriction generation unit 209b. ing. When the left and right pedals are depressed, the crankshaft 202 is twisted by the pedaling force (manpower driving force), so that the torsion state of the human power transmission body 203 to which the manpower driving force from the crankshaft 202 is transmitted is indicated by the torque sensor 209. It is detected by.

  Moreover, in the motor drive unit 200 disclosed in Patent Document 2, a rotation sensor 220 that is externally fitted to the crankshaft 202 and detects the rotation of the resultant force body 205 that rotates at the same rotational speed as the crankshaft 202 is provided. Although not described in the specification, it is illustrated. As described above, when the rotation sensor 220 for detecting the rotation of the resultant force body 205 and the rotation of the crankshaft 202 is provided, it can be detected that the pedal 8 is depressed and rotated. In place of the rotation sensor 220, a rotation sensor for detecting the rotation of the crankshaft can be disposed in the vicinity of the magnetostrictive torque sensor. According to this configuration, the rotation of the crankshaft is detected. be able to. Here, as a method of detecting the rotation of the crankshaft or the resultant force body 205 by the rotation sensor, the rotation is performed by attaching a rotating body in which a plurality of magnets having different polarities are embedded in the circumferential direction to the crankshaft or the resultant force body 205. It is conceivable to detect the polarity reversal caused by the rotation sensor.

JP 2009-208710 A Japanese Patent Laid-Open No. 10-250673

  However, in the conventional single-shaft motor drive unit 200 as shown in FIG. 14, the rotation sensor 220 is configured to detect the rotation of the resultant force body 205 that rotates at the same rotational speed as the crankshaft 202. The rotational states of the resultant body 205 and the crankshaft 202 can be read only with relatively low accuracy (low resolution). Therefore, when the rotation sensor detects the reversal of polarity due to rotation by attaching a rotating body in which a plurality of magnets having different polarities are embedded in the circumferential direction to the resultant force body 205, the number of poles by the magnet is not extremely increased. And the resolution of the rotation state cannot be increased. A similar problem occurs when a rotating body in which a plurality of magnets having different polarities in the circumferential direction are attached to the crankshaft to detect the rotational state.

  Further, if a large number of magnets are embedded in the resultant body 205 or the rotating body attached to the crankshaft, the magnetic field in the vicinity of the torque sensor 209 may be disturbed, resulting in noise during torque detection, and the detection capability of the torque sensor 209. May decrease.

  In addition, in this type of single-shaft motor drive unit, a control unit composed of electronic components, a control board, etc. is disposed on the side of the speed reduction mechanism, which is a region that avoids the crankshaft projecting on both sides. (However, it is not shown in Patent Document 2). However, when a rotation sensor is disposed in the vicinity of the resultant force body 205 or in the vicinity of the rotating body attached to the crankshaft, a substrate for controlling the rotation sensor at a position where the rotation sensor is provided or in the vicinity thereof. Must be arranged separately from the control unit, resulting in an increase in manufacturing cost.

  The present invention solves the above-described problem, and is a single-shaft motor that can detect the rotation state of the crankshaft with high accuracy (with high resolution) and can maintain a good torque detection capability. It is an object of the present invention to provide an electrically assisted bicycle including a drive unit.

  In order to solve the above-described problems, the present invention provides a motor drive unit having a motor disposed at an intermediate position between a front wheel and a rear wheel, and an auxiliary force generated by the motor to a human-powered driving force by a pedaling force from a pedal. An electrically assisted bicycle that is capable of traveling by applying a driving force for detecting the human driving force by transmitting the human driving force to an outer periphery of a crankshaft to which a human driving force from a pedal is transmitted. A cylindrical human power transmission body in which a magnetostriction generating portion of the torque sensor is formed is disposed, and a human power driving force transmitted through the human power transmission body and an auxiliary driving force from the motor are provided on the outer periphery of the crankshaft. A combined force body to be combined is disposed, and a combined force obtained by combining the manpower driving force and the auxiliary driving force by the resultant force body is a driving force output wheel body coaxial with the crankshaft, and the manpower driving force output wheel body. Endless It is configured to be transmitted to the rear wheels via the power transmission body, and has a plurality of reduction gears in the transmission path of the auxiliary driving force extending between the motor and the resultant power body to reduce the rotation from the motor. A speed reduction mechanism for transmitting to the resultant force body is disposed, and a rotation body that is rotated in conjunction with the crankshaft at a rotational speed greater than the crankshaft is disposed in the speed reduction mechanism, and the rotation of the rotation body A rotation detector for detecting the rotation is provided.

  With this configuration, a rotating body that rotates in conjunction with the crankshaft at a higher rotational speed than the crankshaft is disposed in the speed reduction mechanism provided in the transmission path of the auxiliary driving force between the motor and the resultant power body, Since a rotation detector that detects the rotation of the rotating body is provided, the rotation state of the crankshaft is more accurate (higher resolution) than when the rotation body is detected by attaching the rotating body to the crankshaft or the human power transmission body. Can be detected. Therefore, even when a plurality of magnets having different polarities in the circumferential direction are embedded in the rotating body, the resolution of the rotating state can be improved without increasing the number of poles by the magnets. Further, since the rotating body is provided not in the crankshaft or the human power transmission body but in the speed reduction mechanism, the possibility of disturbing the magnetic field in the vicinity of the torque sensor provided in the human power transmission body can be minimized. Thus, the detection capability of the torque sensor can be maintained well.

  In the present invention, the motor drive unit has a control board on the side of the speed reduction mechanism and controls the motor drive unit, and the rotation detector faces the rotating body. And is attached to the control board. With this configuration, it is not necessary to provide a control board for detecting the rotation state of the rotating body separately from the control board provided in the control unit that controls the motor drive unit.

  Preferably, the rotating body is attached to a reduction gear support shaft, whereby a reduction gear support shaft that rotates in conjunction with the crankshaft at an extremely higher rotational speed than the crankshaft. Since the rotation state can be detected, the rotation state of the crankshaft can be detected with extremely high accuracy (high resolution). In addition, even when a magnet is embedded in the rotating body by attaching the rotating body to a reduction gear support shaft separated from the crankshaft or the human power transmitting body, the vicinity of the torque sensor provided in the human power transmitting body The possibility of disturbing the magnetic field can be minimized.

  A one-way clutch for cutting a manpower driving force that does not transmit the manpower driving force from the resultant force member side to the motor side is disposed between the reduction gear support shaft and the large-diameter gear portion that meshes with the motor output side gear. You may set up. With this configuration, even if the pedal is scooped and rotated when the remaining capacity of the battery runs out, it is not necessary to rotate the motor by the one-way clutch for cutting the manpower driving force, and extra force is applied to the pedal. You don't have to spend it.

  As the rotation detector, a magnetic sensor separate from the torque sensor may be used, but instead, an optical sensor may be used as the rotation detector.

  In addition, a one-way clutch is not provided in a driving force transmission path extending between the crankshaft, the manpower transmitting body, and the resultant force body, and the crankshaft, the manpower transmitting body, and the resultant force body are relatively rotated. Regardless of the direction, the human power transmission body and the resultant power body may be rotated as the crankshaft rotates.

  According to this configuration, since the rotation of the crankshaft is always transmitted in conjunction with the rotating body, the rotation of the crankshaft can always be detected satisfactorily. In addition, when a one-way clutch is provided in a driving force transmission path extending between the crankshaft, the human power transmission body, and the resultant power body, the human power transmission body provided with the magnetostriction generating portion of the torque sensor is Although vibration due to the directional clutch may be transmitted, the one-way clutch is not disposed in the driving force transmission path extending between the crankshaft, the manpower transmitting body, and the resultant force body as described above. Vibration due to the one-way clutch is not transmitted to the transmission body, and the torque (manpower driving force) can be detected well. In addition, since it is not necessary to assemble a one-way clutch to the human power transmission body, a material that can be selected from a wide range of materials for the human power transmission body and has high torque detection capability can be used.

  Further, when a one-way clutch is not provided in the driving force transmission path extending between the crankshaft, the manpower transmission body, and the resultant force body, based on the torque fluctuation state and the output signal detected by the rotation detector. And a control unit capable of estimating the position of the pedal corresponding to the position of the crank shaft in the rotational direction. That is, in this configuration, a one-way clutch is provided between a crankshaft on which a pedal is assembled and a resultant body to which a driving force output wheel body to which an endless driving force transmission body such as a chain is applied is attached. Since it is not provided, the relative positions of the pedal, the crankshaft, the manpower transmission body, and the resultant power body with respect to the rotation direction do not vary. Therefore, the position of the pedal and the like can be estimated from the rotational position of the crankshaft, the manpower transmission body, the resultant power body, and the torque fluctuation state by the control unit.

  Therefore, for example, a transmission that can adjust the shift timing when a shift is instructed is provided, and when the shift is instructed, the control unit may shift at a timing at which the pedaling force acting on the pedal is estimated to be small. Good. With this configuration, when a shift is instructed, the pedal is applied to the passenger's feet at a timing (for example, a timing at which the pedal is positioned at the top dead center or the bottom dead center), which is preferable as a shift timing, and the pedaling force acting on the pedal is reduced. It is possible to shift the gears satisfactorily while minimizing the burden on the vehicle.

  Further, the present invention is characterized in that a coaster brake that operates when the pedal is rotated in the direction opposite to the rotation direction during forward traveling is disposed on the hub of the rear wheel. Thus, even when the coaster brake is disposed on the hub of the rear wheel, a one-way clutch is not disposed in the driving force transmission path extending between the crankshaft, the manpower transmission body, and the resultant force body. Therefore, the rotation of the crankshaft is always transmitted to the resultant force body, so when the pedal is rotated in the reverse direction to the forward travel, this rotation is transmitted well to the coaster brake, and the coaster brake is operated well. be able to.

  A one-way clutch for cutting off auxiliary driving force that prevents transmission of auxiliary driving force from the motor side to the crankshaft side in a driving force transmission path extending between the crankshaft, the manpower transmission body, and the resultant force body. In this case, in the state where the one-way clutch is connected, the rotation state of the crankshaft can be detected.

  Further, according to the present invention, the motor, the resultant body, the speed reduction mechanism, and the control unit are incorporated in the motor drive unit, and the motor and the control unit overlap in a side view and are arranged on opposite sides in the width direction. It is characterized by being.

  With this configuration, the area of the motor drive unit as viewed from the side (projected area from the lateral direction) can be particularly reduced (can be made compact) as a uniaxial motor drive unit. Further, since the motor and the control unit are disposed on the opposite sides in the width direction in the motor drive unit, the control unit is hardly affected by the heat of the motor, and good reliability can be maintained.

  According to the present invention, a rotating body that rotates in conjunction with the crankshaft is disposed at a speed lower than that of the crankshaft in a speed reduction mechanism provided in a transmission path of auxiliary driving force that extends between the motor and the resultant body. By providing a rotation detector that detects the rotation of the rotating body, the rotation state of the crankshaft can be detected with high accuracy (high resolution). Therefore, even when a plurality of magnets having different polarities in the circumferential direction are embedded in the rotating body, the resolution of the rotating state can be increased without increasing the number of poles by the magnets, and an increase in manufacturing cost can be suppressed. Further, since the rotating body is provided not in the crankshaft or the human power transmission body but in the speed reduction mechanism, the possibility of disturbing the magnetic field in the vicinity of the torque sensor provided in the human power transmission body can be minimized. Thus, the detection capability of the torque sensor can be maintained well and the reliability is improved.

  In addition, a control board is provided on the side of the speed reduction mechanism in the motor drive unit, and a control unit for controlling the motor drive unit is disposed, and the control board is placed in a posture facing the rotating body. By attaching to the control board, it is not necessary to provide a control board for detecting the rotation state of the rotating body separately from the control board provided in the control unit for controlling the motor drive unit, thereby suppressing an increase in manufacturing cost. Can do.

  Further, by attaching the rotating body to the reduction gear support shaft, the rotation state of the crankshaft can be detected with extremely high accuracy (high resolution), and even when a magnet is embedded in the rotating body, The possibility of disturbing the magnetic field in the vicinity of the torque sensor provided in the human power transmission body can be minimized, and the reliability is improved.

  In addition, a one-way clutch for cutting a manpower driving force that does not transmit the manpower driving force from the resultant force member side to the motor side is arranged between the reduction gear support shaft and the large-diameter gear portion that meshes with the motor output side gear. Therefore, even if the pedal is scooped and rotated when the remaining capacity of the battery is exhausted, it is not necessary to rotate the motor by the one-way clutch for cutting the human-powered driving force. No need to spend

  In addition, a one-way clutch is not provided in a driving force transmission path extending between the crankshaft, the manpower transmitting body, and the resultant force body, and the crankshaft, the manpower transmitting body, and the resultant force body are relatively rotated. Regardless of the direction, the rotation of the crankshaft is always transmitted in conjunction with the rotating body by configuring the human power transmission body and the resultant power body to rotate with the rotation of the crankshaft. Can always be detected satisfactorily. Further, vibration due to the one-way clutch is not transmitted to the human power transmission body, and the torque (human power driving force) can be detected well. Further, a material that can be selected from a wide range of materials for the human power transmission body and that has a high torque detection capability can be used.

  Further, the position of the pedal can be estimated from the rotation position of the crankshaft, the manpower transmission body, the resultant force body, and the torque fluctuation state by the control unit. In addition, a transmission that can adjust the shift timing when a shift is instructed is provided, and when the shift is instructed, the control unit shifts the gear at a timing at which it is estimated that the pedaling force acting on the pedal is reduced. It is possible to make a good shift while minimizing the burden on the passenger's foot at a timing preferable as the timing.

  In addition, a one-way clutch for cutting a manpower driving force that does not transmit the manpower driving force from the resultant force member side to the motor side is arranged between the reduction gear support shaft and the large-diameter gear portion that meshes with the motor output side gear. Therefore, even if the pedal is scooped and rotated when the remaining capacity of the battery is exhausted, it is not necessary to rotate the motor by the one-way clutch for cutting the human-powered driving force. No need to spend Further, the rotation of the crankshaft can always be detected satisfactorily regardless of the rotation state of the motor.

  In addition, the motor, the resultant body, the speed reduction mechanism, and the control unit are incorporated in the motor drive unit, and the motor and the control unit are overlapped in a side view and disposed on opposite sides in the width direction to drive the motor. The area of the unit as viewed from the side (projected area from the lateral direction) can be made particularly small (can be made compact) as a uniaxial motor drive unit, and the controller is less susceptible to the heat of the motor. Good reliability can be maintained.

Overall side view of a power-assisted bicycle according to an embodiment of the present invention Partially cutaway side view of the same electric assist bicycle (A) And (b) is a right side view and a left side sectional view of the motor drive unit of the same electric assist bicycle (drive sprocket is omitted) Plan sectional view of the motor drive unit of the electric assist bicycle Main part enlarged plan sectional view of the motor drive unit of the electric assist bicycle An exploded perspective view of the rear wheel hub of the same electric assist bicycle In the longitudinal sectional view of the hub of the rear wheel of the same electric assist bicycle, the rear wheel is driven to rotate by the pedal force In the longitudinal sectional view of the hub of the rear wheel of the same electric assist bicycle, the coaster brake is activated by rotating the pedal in the opposite direction to the forward traveling state, or the pedal rotation is stopped during traveling Overall side view of a power-assisted bicycle according to another embodiment of the present invention The expanded plane cross-sectional view of the motor drive unit in the electrically assisted bicycle concerning other embodiments of the present invention. Side view of a rotation detector and a rotating body in a power-assisted bicycle according to still another embodiment of the present invention. Side view of a biaxial motor drive unit and its vicinity in a conventional electric assist bicycle Side view of a uniaxial motor drive unit in a conventional electric assist bicycle Plan sectional view of the same axis motor drive unit

  Hereinafter, an electrically assisted bicycle according to an embodiment of the present invention will be described with reference to the drawings. In the following description, the left-right direction and the front-rear direction refer to directions in a state in which the electric assist bicycle 1 is boarded in the traveling direction. The configuration of the present invention is not limited to the configuration described below.

  1 and 2 is an electrically assisted bicycle according to an embodiment of the present invention. As shown in FIG. 1 and FIG. 2, this electric assist bicycle 1 includes a metal frame 2 including a head pipe 2a, a front fork 2b, a main pipe 2c, a standing pipe 2d, a chain stay 2e, a seat stay 2f, and the like. A front wheel 3 rotatably attached to the lower end of the front fork 2b, a rear wheel 4 rotatably attached to the rear end of the chain stay 2e, a handle 5 for changing the direction of the front wheel 3, a saddle 6, A crank 7 and a pedal 8 to which a manpower driving force composed of a pedaling force is applied, an electric motor 21 (see FIG. 4) as a driving source for generating an auxiliary driving force (assist force), and various electric devices including the motor 21 A battery comprising a motor drive unit 20 provided with a control unit 24 (see FIG. 4) for performing control, and a secondary battery for supplying drive power to the motor 21 12, a hand operating part (not shown) which is attached to the handle 5 and can be operated by a passenger and the like, and is attached so as to rotate integrally with the crankshaft 7a so as to rotate integrally. A driving sprocket (also referred to as a front sprocket, a crank sprocket or a front gear) 13 serving as a driving force output wheel body for outputting a resultant force in which the driving forces are combined, and a hub (also referred to as a rear hub) 9 of the rear wheel 4 are attached. A chain as an endless driving force transmission body wound endlessly in a rotatable state across a rear sprocket (sometimes referred to as a rear gear) 14 as a rear ring body and a drive sprocket 13 and a rear sprocket 14 15 and a chain cover 17 that covers the chain 15 and the like from the side. The battery 12 is an example of a battery and a secondary battery is preferable. However, another example of the battery may be a capacitor. The crank 7 includes a crank arm 7b provided on each of the left and right sides, and a crank shaft 7a that connects the left and right crank arms 7b. A pedal 8 is rotatably attached to an end of the crank arm 7b.

  As shown in FIG. 1 and FIG. 2, also in this electrically assisted bicycle 1, the motor drive unit 20 has an intermediate position between the front wheel 3 and the rear wheel 4 (more specifically, an intermediate position, such as substantially behind the crankshaft 7a). At the bottom). With such an arrangement, the motor drive unit 20 having a relatively large weight is arranged at the center in the front-rear direction of the electrically assisted bicycle 1, so that the front wheels 3 and the rear wheels 4 can be easily lifted, and the travel path The vehicle body (such as the frame 2) of the electrically assisted bicycle 1 can be easily handled even if there is a step, and the running stability is also good.

  3A and 3B are a right side view and a left side cross-sectional view of the motor drive unit 20 (the drive sprocket 13 is omitted), and FIG. 4 is a plan cross-sectional view of the motor drive unit 20.

  As shown in FIGS. 3 (a), 3 (b), and 4, the motor drive unit 20 includes a motor case 22a, a left case 22b, and a right case 22c. A crankshaft 7a penetrates the front portion of the unit 20 from side to side. Further, a substantially cylindrical human power transmission body 28 to which the human power driving force from the crank shaft 7a is transmitted to the outer periphery of the crankshaft 7a, and the human power driving force transmitted through the human power transmission body 28 and the motor 21 A resultant body 29 that combines the auxiliary driving force is provided. Further, a speed reduction mechanism 25 having a speed reduction gear 36 and the like is disposed at the center portion in the front-rear direction of the unit case 22, the motor 21 is disposed on the rear left side in the unit case 22, and the rear right side in the unit case 22 is disposed. In addition, a control board 24a provided with electronic components for performing various electrical controls and a control unit 24 having a storage unit for various information are disposed. Reference numeral 39 denotes a partition cover (which partitions the area where the speed reduction mechanism 25 (specifically, a large-diameter gear part 36d of the speed reduction gear 36 described later) and the like are provided, and the area where the control unit 24 is provided ( Oil avoidance cover).

  The motor drive unit 20 will be described in more detail. As shown in FIG. 4 and the like, the crankshaft 7a is rotatably disposed by bearings 26 and 27 with the front portion of the motor drive unit 20 penetrating left and right. A cylindrical human power transmission body 28 is fitted on the outer periphery of the left side portion of the crankshaft 7a through a serration portion (or spline portion) 7c in a state of rotating integrally. A serration portion (or spline portion) 28b is also formed at a location corresponding to the serration portion (or spline portion) 7c of the crankshaft 7a on the inner periphery of the human power transmission body 28, so that the serration portion (or spline portion) of the crankshaft 7a is formed. ) Meshed with 7c.

  A magnetostriction generating portion 31b having magnetic anisotropy is formed on the outer peripheral surface of the human power transmission body 28, and a coil 31a is disposed on the outer periphery via a certain gap (space). The generator 31b and the coil 31a constitute a magnetostrictive torque sensor (human power detector) 31. As a result, the manpower driving force from the crankshaft 7 a is transmitted to the manpower transmitting body 28, and the manpower driving force is detected by the torque sensor 31. In the magnetostrictive torque sensor 31, the magnetostriction generator 31 b is formed in a spiral shape that forms, for example, +45 degrees and −45 degrees with respect to the axial direction of the human power transmission body 28. When the human driving force is transmitted to the magnetic force generator 28, the magnetostriction generating portion 31b on the surface of the human power transmitting body 28 is distorted to generate an increase portion and a decrease portion of the magnetic permeability. Therefore, by measuring the inductance difference of the coil 31a. It is comprised so that the magnitude | size of a torque (manpower driving force) can be detected. In this embodiment, the above configuration is configured to detect that the crankshaft 7a is rotated in the opposite direction, but the present invention is not limited to this.

  The resultant force body 29 for synthesizing the manpower driving force and the auxiliary driving force is a position adjacent to the right side of the manpower transmitting body 28 on the outer periphery of the crankshaft 7a and is rotatable with respect to the crankshaft 7a. The serration portion (or spline portion) 28a formed on the outer periphery of the right end portion of the human power transmission body 28 and the serration portion (or spline portion) 29a formed on the inner periphery of the left end portion of the resultant force body 29 are disposed. It is mated. In this embodiment, a serration portion (or spline portion) 29 a formed on the inner periphery of the left end portion of the resultant force body 29 is externally fitted to the serration portion (or spline portion) 28 a of the human power transmission body 28. Thus, the transmission of force between the crankshaft 7a and the manpower transmitting body 28 and between the manpower transmitting body 28 and the resultant force body 29 (that is, between the crankshaft 7a, the manpower transmitting body 28 and the resultant force body 29). (Path) is not provided with a one-way clutch (one-way clutch for cutting auxiliary driving force), and as a result, the manpower driving force transmitted to the crankshaft 7a is transmitted from the manpower transmitting body 28 to the resultant force body 29. Thus, the crankshaft 7a, the manpower transmission member 28, and the resultant force member 29 are configured to always rotate integrally.

  Further, as shown in FIG. 4, a large-diameter gear portion 29 b for inputting auxiliary driving force from the motor 21 is integrally formed on the outer periphery of the left side portion of the resultant force body 29 in the motor driving unit 20. Further, the driving sprocket 13 is fitted on the outer periphery of the right end portion of the resultant body 29, and the resultant body 29 and the driving sprocket 13 rotate integrally. Note that the crankshaft 7 a is rotatably supported via the resultant force body 29 by a bearing 27 fitted on the resultant force body 29. A thin bearing or the like may be disposed between the resultant body 29 and the crankshaft 7a.

  The rotating shaft 21a and the rotor portion 21b of the motor 21 are rotatably supported by bearings 32 and 33. Moreover, the rotating shaft 21a of the motor 21 protrudes to the right side, and the tooth | gear part 21c is formed in the outer periphery of this protrusion part. The reduction mechanism 25 is configured to reduce the rotation of the motor 21 through the reduction gear 36 and to amplify the rotational torque (auxiliary driving force) and transmit the amplified torque to the large-diameter gear portion 29b of the resultant body 29. .

  Here, the support shaft (reduction gear support shaft) of the reduction gear 36 is an example of a reduction gear small-diameter support shaft portion that is rotatably supported by bearings 34 and 35 (an example of a reduction gear support shaft). , Simply abbreviated as a small-diameter support shaft portion) 36a and a reduction gear large-diameter support shaft portion having a larger diameter than this (this is another example of a reduction gear support shaft, hereinafter simply abbreviated as a large-diameter support shaft portion). 36b is integrally formed. In addition, a small reduction gear portion (an example of a reduction gear portion, hereinafter simply referred to as a small gear portion) 36c, which is separate from the small diameter support shaft portion 36a, is press-fitted on the outer periphery of the small diameter support shaft portion 36a. It is assembled so as to rotate integrally through a serration portion (or spline portion) or the like. The small diameter gear portion 36 c is engaged with the large diameter gear portion 29 b of the resultant force body 29. On the other hand, a reduction large-diameter gear portion (another example of the reduction gear portion, hereinafter simply referred to as a large-diameter gear portion) 36d is disposed on the outer periphery of the large-diameter support shaft portion 36b of the reduction gear 36. The large-diameter gear portion 36d is meshed with the tooth portion 21c of the rotating shaft 21a of the motor 21, but between the large-diameter support shaft portion 36b and the large-diameter gear portion 36d in the reduction gear 36, A one-way clutch 37 for cutting a manpower driving force is provided so as not to transmit the rotational driving force from the resultant body 29 to the motor 21 side.

  In the one-way clutch 37, an inner peripheral portion of the large-diameter gear portion 36d of the reduction gear 36 based on the motor output (auxiliary driving force) is opposed to the one-way clutch 37 such that a certain amount of auxiliary driving force is output during traveling. When rotating in the direction in which the drive sprocket 13 moves forward relative to the outer peripheral portion of the large-diameter support shaft portion 36b (that is, the number of rotations in the forward direction of the inner periphery of the large-diameter gear portion 36d of the reduction gear 36) Is larger than the rotational speed in the forward direction of the outer periphery of the large-diameter support shaft portion 36b facing this), the auxiliary driving force transmitted to the large-diameter gear portion 36d of the reduction gear 36 is increased as it is. It operates to transmit to the diameter support shaft portion 36b. The auxiliary driving force is transmitted to the large diameter gear portion 29b of the resultant force body 29 via the small diameter support shaft portion 36a and the small diameter tooth portion 36c. As a result, in the resultant force body 29, the manpower driving force and the auxiliary driving force are combined, and the combined force is transmitted from the drive sprocket 13 to the rear wheel 4 via the chain 15.

  On the other hand, when the remaining capacity of the battery 12 is lost and the pedal 8 is stroked in a state where the auxiliary driving force is not output from the motor 21, the large-diameter gear portion 36d of the reduction gear 36d based on the motor output (auxiliary driving force) is used. When the inner peripheral portion rotates in a direction opposite to the direction in which the drive sprocket 13 moves forward relative to the outer peripheral portion of the large-diameter support shaft portion 36b facing the inner peripheral portion (the large-diameter gear portion of the reduction gear 36) 36d when the rotational speed in the forward direction of the inner periphery of 36d is smaller than the rotational speed in the forward direction of the outer periphery of the large-diameter support shaft portion 36b opposite to this. The auxiliary driving force transmitted to is disconnected by the one-way clutch 37 and is not transmitted to the large-diameter support shaft portion 36b.

  Thereby, when the remaining capacity of the battery 12 is lost and the pedal 8 is scooped in a state where the auxiliary driving force is not output from the motor 21, the small-diameter gear portion 36c, the small-diameter support shaft portion 36a and the large-diameter shaft are driven by the manual driving force. Although the support shaft portion 36b is rotated, the large-diameter gear portion 36d, the rotation shaft 21a of the motor 21 and the rotor portion 21b are not rotated.

  Further, in addition to the above configuration, as shown in FIGS. 4 and 5, the support shaft of the reduction gear 36 (reduction gear support shaft), more specifically, the right end of the large-diameter support shaft portion 36b in the reduction gear support shaft. A rotating body 11 for detecting the rotation of the large-diameter support shaft portion 36b is attached to the outer periphery of the portion. Further, a rotation detector 10 made of a magnetic sensor is provided in a posture facing the rear end portion of the rotating body 11 from the right side. The small-diameter gear portion 36c of the reduction gear 36 is set to ¼ to 歯 the number of teeth of the large-diameter gear portion 29b of the resultant force member 29 meshing with the reduction gear 36, and accordingly, the large-diameter support shaft portion 36b. The speed reduction gear support shaft including the rotating body 11 and the rotating body 11 are linked to the crankshaft 7a, the manpower transmission body 28, and the resultant force body 29, and have a rotational speed greater than that of the crankshaft 7a. Rotates at 5 times the number of rotations. A plurality of magnets 11 a having different polarities are embedded in the circumferential direction in the vicinity of the outer peripheral portion of the right side surface of the rotating body 11 so that the polarities are alternately switched with respect to the circumferential direction. As shown in FIGS. 3B, 4, and 5, the rotation detector 10 is disposed in the control unit 24 and is attached to the control board 24 a of the control unit 24.

  In this embodiment, a hole 39a is formed and communicated with a partition cover (oil avoidance cover) 39 between the rotation detector 10 and the rotator 11, and the polarity variation state by the magnet 11a. It can be detected well. However, the present invention is not limited to this, and the whole or a part of the partition cover (oil avoidance cover) 39 may be formed of a material that does not block magnetism between the rotation detector 10 and the rotating body 11.

  The electric bicycle 1 is also provided with a rim brake that presses a brake shoe that operates by operating a brake lever against the rim of the front wheel, a band brake or a roller brake of the rear wheel, etc. as a brake device for the rear wheel 4. Absent. Then, instead of these brake devices, the pedal 8 is moved forward to the rear hub 9 (see FIG. 2, but actually, the rear hub 9 is provided on the other side of the rear sprocket 14 shown in FIG. 2). A coaster brake 60 as shown in FIG. 6 is provided in which the rear wheel 4 is braked by rotating in the direction opposite to the rotation direction during traveling. As a brake device for the front wheel 3, a caliper brake or a rim brake that operates by operating a brake lever may or may not be provided (in FIG. 1, a brake device for the front wheel 3 is provided). Shows no case).

  FIG. 6 is an exploded perspective view of the hub (rear hub) 9 of the rear wheel 4 on which the coaster brake 60 is provided, and FIGS. 7 and 8 are sectional views of the rear hub. In this embodiment, a coaster brake mechanism 60 of the type “roller clutch drive type” for a bicycle coaster hub mechanism B type defined in JIS (Japanese Industrial Standards) D9419 is used. A coaster brake 60 is disposed inside the hub body that rotates integrally with the wheel 4.

  As shown in FIGS. 6 to 9, the coaster brake 60 is rotatably fitted on the hub axle 67 of the rear wheel 4, and the rear sprocket 14 rotates integrally with the outer periphery of one end side (right end side in FIG. 6). The protrusion 61a, the large-diameter cam surface 61b, and the small-diameter cam surface 61c as shown in FIGS. 7 and 8 are formed on the other end side (left end side in FIG. 6) at appropriate intervals in the circumferential direction. The driving body 61, a roller 62 is disposed at an appropriate interval in the circumferential direction at a portion near the outer periphery, and a cam base 63 having a cam portion 63a protruding leftward in FIG. 6 along the axial direction. An expander 64 having an inclined cam portion 64a engaged with the cam portion 63a and having a tapered surface 64b, a brake shoe 65 capable of expanding and contracting in the radial direction and slidably contacting the inner peripheral surface of the rear hub 9, and a brake shoe And it is configured to over 65 etc. and a brake cone 66 having a movable tapered surface 66a on the outside.

  When the pedal 8 is rotated in the normal traveling direction (rotational direction during forward traveling, also referred to as the forward direction), the drive body 61 is moved in the g direction shown in FIG. 7 via the chain 15 and the rear sprocket 14. In association with this rotation, the roller 62 is pressed outward by the large diameter portion 61 b of the driving body 61. As a result, the roller 62 is sandwiched between the driving body 61 and the hub body of the rear hub 9 in a state of being strongly pressed, whereby the hub body is integrated with the driving body 61 so that the rear wheel 4 is integrated. The whole is also rotated. At this time, the cam portion 63a of the cam base 63 is in contact with a thin thickness portion with respect to the axial direction of the inclined cam portion 64a of the expander 64, and the expander 64 is positioned on the right side in FIG. The taper surface 64b of the expander 64 is not in contact with the brake shoe 65, and the brake shoe 65 is also separated from the inner peripheral surface of the rear hub 9 without being enlarged in diameter.

  On the other hand, when the pedal 8 is rotated in a direction opposite to the rotation direction during forward traveling and the rear sprocket 14 is rotated in the reverse direction via the chain 15, as shown in FIG. The roller is rotated in the h direction, which is the same direction as the rear sprocket 14, so that the roller 62 is in contact with the small-diameter cam surface 61 c of the driving body 61 and has a gap from the inner peripheral surface of the hub body. However, when the cam base 63 is rotated in the h direction via the roller 62 by the rotation of the driving body 61 in the h direction, the expander 64 is in contact with the cam portion 63a of the cam base 63 by the inclined cam portion 64a. Is moved to the left in FIG. As a result, the brake shoe 65 is pressed from both sides by the tapered surface 64b of the expander 64 and the tapered surface 66a of the brake cone 66 to expand the diameter, and is strongly pressed against the inner peripheral surface of the hub body of the rear hub 9. As a result, the rear wheel 4 is braked via the rear hub 9.

  When the pedal 8 is stopped during traveling and the rotation of the rear sprocket 14 is stopped via the chain 15, there is no force that causes the drive body 61 to rotate in the g direction as shown in FIG. Therefore, as shown in FIG. 8, the roller 62 is in a state of having a gap from the inner peripheral surface of the rear hub 9 by approaching the small-diameter cam surface 61 c side of the driving body 61. Further, since the driving body 61 is not rotated, the cam base 63 is not rotated, so that the expander 54 remains in a state of being located on the right side in FIG. 6 and the taper surface 64b of the expander 64 abuts against the brake shoe 65. Thus, the brake shoe 65 is also separated from the inner peripheral surface of the rear hub 9 without being expanded in diameter. As a result, even if the rear hub 9 is rotating, the rotational force of the rear hub 9 is not transmitted to the driving body 61 and the rear sprocket 14, and a free wheel (one-way clutch mechanism or As in the case where the ratchet mechanism is provided, the idling state is maintained.

  In this embodiment, the case of using the “roller clutch drive type” coaster brake 60 has been described. However, the present invention is not limited to this, and instead of this, a “taper cone drive type” coaster is used. A brake or a “multi-plate” coaster brake may be used.

  In the above configuration, when the pedal 8 is stepped on during forward travel, the manpower driving force based on the pedaling force applied to the pedal 8 is transmitted from the crank shaft 7a to the resultant body 29 via the manpower transmitting body 28, and the manpower driving force is This is detected by a torque sensor 31 provided on the human power transmission body 28. Then, an auxiliary driving force corresponding to the human driving force is transmitted to the resultant force body 29 through the reduction gear 36 of the speed reduction mechanism 25 and the like, and the resultant force combined by the resultant force body 29 is moved from the drive sprocket 13 to the chain 15. Via the rear wheel 4. Thereby, it is possible to travel easily on an uphill or the like by applying an auxiliary driving force (assist force) of the motor 21 corresponding to the human power driving force.

  On the other hand, when the rider stops pedaling while traveling, the rotation of the crankshaft 7a and the resultant force body 29 is also stopped. Accordingly, the stopped state is detected by the rotation detector 10, and the motor 21 is turned on. Stops or brakes immediately. Thereby, it is possible to prevent the auxiliary driving force from the motor 21 from acting on the pedal 8, and it is not necessary to apply an extra force to the pedal 8.

  Further, when the occupant rotates the pedal 8 in the reverse direction during traveling, the drive sprocket 13 is also rotated in the reverse direction via the crankshaft 7a, the manpower transmission body 28, and the resultant force body 29. It is transmitted to the coaster brake 60 provided with the rear hub 9 via the chain 15, and the coaster brake 60 operates.

  In these operations, the conventional single-shaft motor drive unit is provided with a one-way clutch at the end of the human power transmission body or resultant force body to which the torque sensor is attached. Vibration, cam engagement and over-traveling vibrations are directly transmitted to the end of the human power transmission body or combined power body, resulting in noise at the time of torque detection, which may reduce the torque detection capability. It was. In addition, when the torque detection capability is reduced as described above, it may be difficult to perform advanced control on the torque value or to perform quick control on the torque value. Even if the coaster brake is installed on the hub of the rear wheel, the rotation of the pedal cannot be transmitted to the drive sprocket or chain when the pedal is rotated in the opposite direction to the forward travel, so it can be used for the coaster brake. could not.

  On the other hand, in the embodiment of the present invention, no one-way clutch is provided in the driving force transmission path extending between the crankshaft 7a, the human power transmission body 28, and the resultant power body 29. Even if the magnetostriction generating part 31 b of the torque sensor 31 is provided, vibration due to the one-way clutch is not transmitted to the human power transmission body 28. Thereby, torque (manpower driving force) can be detected satisfactorily, and the reliability of the electrically assisted bicycle 1 is improved. In addition, since it is not necessary to assemble a one-way clutch to the human power transmission body 28, a material that can be selected from a wide range of materials for the human power transmission body 28 and has high torque detection capability can be used. Thereby, the magnetostriction generation part 31b of the torque sensor 31 which can detect a torque more favorably can be used.

  In addition, according to the above configuration, when the pedal 8 is stopped while being driven or rotated in the reverse direction, this operation is detected by the torque sensor 31 or the rotation detector 10, and the motor 21. Is configured to stop or brake immediately. Thereby, the auxiliary driving force from the motor 21 is prevented from acting on the pedal 8.

  Further, according to the above configuration, even when the coaster brake 60 is disposed on the hub 9 of the rear wheel 4, a one-way clutch is provided in the driving force transmission path extending between the crankshaft 7 a, the manpower transmitting body 28 and the resultant force body 29. Is not disposed at all, and the rotation of the pedal 8 and the crankshaft 7a is always transmitted to the resultant force body 29. Therefore, when the pedal 8 is rotated in the reverse direction to the forward travel, this rotation is the coaster brake 60. The coaster brake 60 can be operated satisfactorily.

  In the above configuration, the rotating body that rotates in conjunction with the crankshaft 7 a at a higher rotational speed than the crankshaft 7 a is provided in the speed reduction mechanism 25 provided in the transmission path of the auxiliary driving force extending between the motor 21 and the resultant force body 29. 11 is arranged, and the rotation detector 10 detects the rotation of the rotating body 11. In particular, in the present embodiment, rotation of the rotating body 11 attached to a reduction gear support shaft (large-diameter support shaft portion 36b) that rotates at a rotational speed 4 to 5 times that of the crankshaft 7a in conjunction with the crankshaft 7a. Is detected by the rotation detector 10. Thereby, the rotation state of the crankshaft 7a can be detected well with 4 to 5 times higher accuracy (high resolution) than when the rotation body 11 is attached to the crankshaft 7a or the human power transmission body 28 to detect the rotation. Can do.

  Even when a plurality of magnets 11a having different polarities in the circumferential direction are embedded in the rotating body 11 as described above, the number of poles of the magnet 11a is not increased (the number of magnets 11a is increased). Even if not, the resolution of the rotation state can be increased, and an increase in manufacturing cost can be suppressed. Further, by attaching the rotating body 11 to the reduction gear support shaft (large-diameter support shaft portion 36 b), the rotating body 11 can be disposed away from the torque sensor 31. As a result, the possibility of disturbing the magnetic field in the vicinity of the torque sensor 31 provided in the human power transmission body 28 can be minimized, and the detection capability of the torque sensor 31 can be maintained well and reliability is improved. Will improve.

  Moreover, in the said embodiment, the control part 24 which has the control board 24a and controls the said motor drive unit 20 is arrange | positioned at the side of the deceleration mechanism 25 in the motor drive unit 20, and the rotation detector 10 is rotated. It is attached to the control board 24a in a posture facing the body 11. With this configuration, it is not necessary to provide a control board for detecting the rotation state of the rotator 11 separately from the control board 24a provided in the control unit 24 that controls the motor drive unit 20, and the control board 24a. It can be incorporated into the inside of the battery, and an increase in manufacturing cost can be suppressed.

  Further, in the above configuration, the rotation detector 10 for detecting the rotation of the resultant force body 29, the manpower transmitting body 28 and the crankshaft 7a is provided, and the resultant force body 29, the manpower transmitting body 28 and the crankshaft 7a are correctly controlled by the control unit 24. When it is detected that the vehicle is rotating in the direction (direction in which the electric assist bicycle 1 moves forward), the pedal 8 is at the top dead center position or the bottom dead center position when the vehicle travels with a temporary force. Even when the torque fluctuates because the stepping force temporarily decreases, for example, the control may be performed so as to suppress the fluctuation of the auxiliary driving force. According to this structure, the fluctuation | variation of the auxiliary drive force at the time of driving | running | working can be suppressed, and the improvement of riding comfort can be aimed at.

  In the above configuration, since the one-way clutch is not provided between the crankshaft 7a on which the pedal 8 is assembled and the resultant body 29 to which the drive sprocket 13 is attached, the pedal 8, The relative positions of the shaft 7a, the human power transmission body 28, and the resultant force body 29 with respect to the rotation direction do not vary. Moreover, the rotation speed of the crankshaft 7a and the rotation speed of the rotary body 11 attached to the reduction gear support shaft (large-diameter support shaft portion 36b) are a constant ratio. Accordingly, the control unit 24 determines the positions of the crankshaft 7a, the manpower transmission body 28, and the resultant force body 29 based on the number of rotations (rotation amount) of the rotating body 11 attached to the reduction gear support shaft (large diameter support shaft portion 36b). The position of the pedal 8 and the like can be estimated from the torque fluctuation state, and various controls may be performed.

  For example, the electrically assisted bicycle 1 has a structure having a plurality of shift stages and a transmission capable of adjusting the shift timing when a shift is instructed, and the control unit 24 determines the torque fluctuation state. Based on the output signal detected by the rotation detector 10, the position of the pedal 8 corresponding to the position of the resultant force body 29 in the rotation direction is estimated, and when the shift is instructed, the pedal 8 is preferable as the shift timing. The speed may be changed at a timing when the applied pedal force becomes small (for example, timing when the pedal 8 is located at the top dead center or the bottom dead center). According to this configuration, when a shift is instructed, the burden on the passenger's foot can be minimized, and at the same time, the shift can be performed satisfactorily.

  In the above configuration, the auxiliary driving force transmission path extending between the motor 21 and the resultant force body 29 is provided with a small-diameter gear portion 36c and a large-diameter gear portion 36d as a plurality of reduction gear portions, and the small-diameter gear portion 36c and A reduction gear 36 of the reduction mechanism 25 having a small-diameter support shaft portion 36a and a large-diameter support shaft portion 36b as a reduction gear support shaft for supporting the large-diameter gear portion 36d is disposed. In this embodiment, the one-way clutch for cutting the manpower driving force that does not transmit the manpower driving force from the resultant force body 29 side to the motor 21 side between the large diameter gear portion 36d and the large diameter support shaft portion 36b. 37 is disposed.

  Thereby, when the remaining capacity of the battery 12 is lost and the pedal 8 is scooped in a state where the auxiliary driving force is not output from the motor 21, the small-diameter gear portion 36c, the small-diameter support shaft portion 36a and the large-diameter shaft are driven by the manual driving force. Although the support shaft portion 36b is rotated, the large-diameter gear portion 36d, the rotation shaft 21a of the motor 21 and the rotor portion 21b are not rotated, and it is not necessary to apply extra force to the pedal 8 (so-called drag resistance is extremely reduced). be able to). Further, there is an advantage that the rotation of the crankshaft 7a can always be detected satisfactorily regardless of the rotation state of the motor 21.

  In the present embodiment, as shown in FIG. 3, since the motor 21 and the control unit 24 are arranged so as to overlap each other when viewed from the side, the area of the motor drive unit 20 when viewed from the side (lateral) There is an advantage that the projection area from the direction) can be made particularly small (compact) as the uniaxial motor drive unit 20. The motor 21 and the control unit 24 are disposed on the opposite side of the width direction when viewed from the front or the plane in the motor drive unit 20 (the motor 21 is disposed on the left side and the control unit 24 is disposed on the right side). The part 24 is hardly affected by the heat of the motor 21, and good reliability can be maintained.

  In the above-described embodiment, the case where the rear hub 9 is provided with the coaster brake 60 has been described. However, the present invention is not limited to this. That is, instead of the coaster brake 60, a rim brake, a band brake, or a roller brake that is braked by operating a brake lever 70 (see FIG. 9) attached to the handle 5 as a general bicycle, as a brake device. Also, the motor drive unit 20 of the above embodiment may be used even when such is provided. In this case, a one-way clutch for stopping the pedal that does not transmit the rotational force of the rear wheel 4 to the chain 15 is disposed on the hub 9 of the rear wheel 4 so that the pedal can be used during forward traveling such as downhill. You may comprise so that 8 may not rotate.

  In the above embodiment, the case where the front transmission is not mounted and the number of drive sprockets 13 is one (one stage) has been described. However, the present invention is not limited to this, and large and small drive sprockets are provided. A front transmission may be installed.

  In the above embodiment, the case where the one-way clutch is not disposed in the transmission path of the driving force across the crankshaft 7a, the manpower transmission body 28, and the resultant force body 29 is described, but the present invention is not limited to this. A one-way clutch 38 for cutting the auxiliary driving force that prevents the auxiliary driving force from the motor 21 side from being transmitted to the crankshaft 7a side in the driving force transmission path extending between the crankshaft 7a, the manpower transmitting body 28 and the resultant force body 29. May be provided. For example, as shown in FIG. 10, the intermediate cylinder 40 is externally fitted in a rotatable state with respect to the crankshaft 7 a and is engaged with the human power transmission body 28 via serration portions (or spline portions) 28 a and 40 b. The one-way clutch 38 for cutting the auxiliary driving force is disposed between the intermediate cylinder 40 and the resultant force body 29. That is, the one-way clutch 38 transmits the manual driving force in the forward direction from the intermediate cylinder 40 to the resultant body 29, but the auxiliary driving force in the forward direction from the resultant body 29 passes through the intermediate cylinder 40. Thus, it is configured not to be transmitted to the crankshaft 7a or the pedal 8 side. Further, in this electrically assisted bicycle, so-called delay control is performed so that the motor 21 continues to rotate for a while even if the rider stops pedaling 8, but the one-way clutch 38 assists driving. The force is cut off to prevent the crankshaft 7a and the pedal 8 from continuing to rotate freely.

  Also in this embodiment, since the one-way clutch 38 is connected when the passenger is stroking the pedal 8, in this state, the rotation state of the crankshaft 7a is based on the rotation state of the rotating body 11. Can be detected. Therefore, even in this configuration, when it is detected from the information from the rotation detector 10 that the crankshaft 7a is rotating in the forward direction (the direction in which the electric assist bicycle 1 moves forward), a force is temporarily applied. Control is performed so as to suppress fluctuations in the auxiliary driving force even when the vehicle travels with the pedal 8 pulled out or when the torque fluctuates due to the pedal 8 being at the top dead center or bottom dead center position and the force to be depressed is temporarily weakened. It is possible to suppress fluctuations in the auxiliary driving force when the vehicle is running, and to improve riding comfort. However, when the one-way clutch 38 is disengaged, the relative position between the crankshaft 7a and the resultant force body 29 is shifted, so the position of the pedal 8 cannot be estimated.

  Moreover, in the said embodiment, although the case where a magnetic sensor was used as the rotation detector 10 was described, it is not restricted to this, You may use an optical sensor as the rotation detector 10. FIG. For example, as shown in FIG. 11, the rotation detector 10 composed of an optical sensor in which the emitting portion 10a and the light receiving portion 10b are adjacent to each other is arranged in the lateral direction (specifically, the rotation direction of the tooth portion 11b of the rotating body 11 described later). Line up two. In addition, the rotating body 11 attached to the large-diameter support shaft portion 36b is provided with a tooth portion 11a extending in the outer peripheral direction in a comb-like shape. And based on the signal of the case where the light reflected on the tooth | gear part 11a of the rotary body 11 is received, and the case where light is not reflected in the groove part 11c between the tooth parts 11a, the rotary body 11 and by extension large-diameter support shaft part 36b. Alternatively, the rotation state and the rotation direction of the crankshaft 7a may be detected. Instead of this, an emitting part and a light receiving part that transmit light and detect the light may be provided.

  The present invention can be applied to various types of electrically assisted bicycles that can travel by adding an auxiliary driving force generated by a motor to a human driving force generated by a pedaling force from a pedal.

DESCRIPTION OF SYMBOLS 1 Electric assist bicycle 2 Frame 3 Front wheel 4 Rear wheel 7 Crank 7a Crankshaft 8 Pedal 9 Hub 10 Rotation detector 11 Rotating body 12 Battery (capacitor)
13 Drive sprocket 14 Rear sprocket 15 Chain (endless drive force transmission body)
DESCRIPTION OF SYMBOLS 20 Motor drive unit 21 Motor 22 Unit case 24 Control part 25 Deceleration mechanism 28 Human power transmission body 29 Combined force body 31 Torque sensor (human power detection part)
36 Reduction gear 37 One-way clutch (one-way clutch for cutting human driving force)
38 One-way clutch (one-way clutch for cutting auxiliary driving force)
40 Intermediate cylinder 60 Coaster brake

Claims (12)

A motor-driven bicycle having a motor provided with a motor is disposed at an intermediate position between the front wheels and the rear wheels, and is capable of traveling by adding an auxiliary driving force generated by the motor to a human-powered driving force by a pedaling force from a pedal. Because
A cylindrical human power transmission body in which a magnetostriction generating portion of a torque sensor for detecting the human power driving force is formed on an outer periphery of a crankshaft to which the human driving power from the pedal is transmitted. Is arranged,
On the outer periphery of the crankshaft, a resultant force body is provided in which the manual driving force transmitted through the manual transmission body and the auxiliary driving force from the motor are combined,
A resultant force obtained by combining the manpower driving force and the auxiliary driving force by the resultant force body is a driving force output wheel body coaxial with the crankshaft, and an endless driving force transmission transmitted over the manpower driving force output wheel body. Configured to be transmitted to the rear wheels through the body,
In the transmission path of the auxiliary driving force extending between the motor and the resultant power body, a speed reduction mechanism that has a plurality of reduction gear portions and decelerates the rotation from the motor and transmits it to the resultant power body is provided.
A rotating body that rotates in conjunction with the crankshaft at a rotational speed greater than that of the crankshaft is disposed in the speed reduction mechanism,
An electrically assisted bicycle comprising a rotation detector for detecting rotation of the rotating body. On the side of the speed reduction mechanism in the motor drive unit, a control unit having a control board and controlling the motor drive unit is disposed,
The electric assist bicycle according to claim 1, wherein the rotation detector is attached to the control board in a posture facing the rotating body.   The electric assist bicycle according to claim 1, wherein the rotating body is attached to a reduction gear support shaft.   A one-way clutch for cutting the manpower driving force that does not transmit the manpower driving force from the resultant force member side to the motor side is disposed between the speed reduction gear support shaft and the large-diameter gear portion that meshes with the output gear of the motor. The electrically assisted bicycle according to claim 3.   The electric assist bicycle according to any one of claims 1 to 4, wherein a magnetic sensor separate from the torque sensor is provided as the rotation detector.   The electric assist bicycle according to claim 1, wherein an optical sensor is provided as the rotation detector. A one-way clutch is not provided in the transmission path of the driving force across the crankshaft, the manpower transmission body and the resultant force body, and the crankshaft, the manpower transmission body and the resultant force body are relatively rotated. The power-assisted bicycle according to any one of claims 1 to 6, wherein the human power transmission body and the resultant power body are also rotated with the rotation of the crankshaft regardless of the direction.   8. A control unit capable of estimating a pedal position corresponding to a position of a crankshaft in a rotation direction based on a torque fluctuation state and an output signal detected by a rotation detector. The electrically assisted bicycle according to any one of the above.   A transmission is provided that can adjust a shift timing when a shift is instructed, and when the shift is instructed, the control unit performs a shift at a timing at which it is estimated that a pedaling force acting on the pedal is reduced. Item 9. The electrically assisted bicycle according to Item 8.   The coaster brake that operates when the pedal is rotated in the direction opposite to the rotation direction during forward traveling is disposed on the hub of the rear wheel. Electric assist bicycle. A one-way clutch for cutting off the auxiliary driving force that prevents the auxiliary driving force from the motor side from being transmitted to the crankshaft side is disposed in the driving force transmission path extending between the crankshaft, the manpower transmission body, and the resultant force body. The electrically assisted bicycle according to any one of claims 1 to 6, wherein the bicycle is a bicycle.   A motor, a resultant body, a speed reduction mechanism, and a control unit are incorporated in a motor drive unit, and the motor and the control unit overlap in a side view and are arranged on opposite sides in the width direction. The electrically assisted bicycle according to any one of claims 1 to 11.

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