JP6754955B2 - Motor drive unit and electrically power assisted bicycle - Google Patents

Description

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

It has a motor that is powered by a capacitor such as a battery, and by detecting the human-powered driving force consisting of the pedaling force applied to the pedal with a torque sensor and adding the auxiliary driving force (assisting force) of the motor corresponding to the human-powered driving force. Electric assisted bicycles that can easily run uphill are already known.

For example, as shown in FIG. 14, in an electrically power assisted bicycle, a motor drive unit 102 having a built-in motor 101 or the like is arranged at a place where a crankshaft 103 is provided (Patent Document 1 and the like). In the electrically assisted bicycle 100 having such an arrangement configuration, the relatively heavy motor drive unit 102 is arranged at a low position in the center of the electrically assisted bicycle 100 in the front-rear direction (that is, between the front wheels and the rear wheels). To. Therefore, in the electrically power assisted bicycle 100 having this arrangement configuration, the front wheels 110 and the rear wheels 111 can be easily lifted as compared with those in which the motor is built in the hub of the front wheels and the hub of the rear wheels, and the traveling path has a step. The vehicle body 113 is easy to handle, and the running stability is also good.

Further, in such a motor drive unit 102, as shown in FIGS. 15 and 16, the outer peripheral surface of the human power transmission body (intermediate shaft) 104 to which the human power drive force from the crankshaft 103 is transmitted and the portion facing the outer peripheral surface thereof. Some structures are provided with a magnetostrictive torque sensor 105 that detects a human-powered driving force. That is, the magnetostrictive generation portion 105a is formed on the outer peripheral surface of the human power transmitter 104, and the coil 105b for detecting the magnetic fluctuation is arranged in a non-contact state so as to face the magnetostrictive generation portion 105a. .. Then, when the left and right pedals 112 (see FIG. 14) are depressed, the crankshaft 103 is twisted by the pedaling force (human-powered driving force), so that the human-powered transmission body 104 in which the human-powered driving force from the crankshaft 103 is transmitted is in a twisted state. Is detected by the torque sensor 105.

In addition, in FIGS. 15 and 16, 106 is an interlocking body (inner portion) connected to a tubular body (outer portion) 109 fitted to the human power transmission body 104 via a one-way clutch (claw member) 107. , 108 are drive sprockets as driving force output wheels attached to the ends of the interlocking body 106.

Here, some motor drive units of electrically power assisted bicycles have a structure that mechanically detects torque (human-powered driving force), for example, as disclosed in Patent Document 2. However, with such a structure, mechanical resistance is generated by the parts coming into contact with each other at the point where torque is detected, so that the remaining amount of battery output is exhausted and auxiliary driving force cannot be added. In some cases, there is a disadvantage that the burden on the passenger becomes large.

On the other hand, in the motor drive unit 102 that detects torque (human-powered driving force) by the magnetostrictive torque sensor 105 as shown in FIGS. 14 to 16, the coil 105b that detects torque (man-powered driving force) generates magnetostriction. It is arranged in a non-contact state with respect to the portion 105a. Therefore, even if the remaining amount of battery output is exhausted and the auxiliary driving force cannot be added, there is almost no burden on the passenger.

Further, in the motor drive unit 102, since the magnetostrictive generating portion 105a is formed in the human power transmission body 104 that is separate from the crankshaft 103, there are also the following advantages. That is, not only the torque (human power driving force) in the rotation direction but also a part of the weight is applied downward from the occupant's foot via the pedal 112 to the both ends of the crankshaft 103 to bend the crankshaft 103. The bending stress to be applied acts. Therefore, if a magnetostrictive generating portion is formed on the crankshaft, this bending stress may become a disturbance factor or noise when detecting torque (human-powered driving force), and the torque detection ability may decrease. In addition, since it is necessary to select a material for the crankshaft that can sufficiently cope with a large bending stress, the material is extremely limited, and in some cases, a material having a low torque detection ability must be used. You may not get it.

On the other hand, in the motor drive unit 102 shown in FIGS. 14 to 16, since the magnetostrictive generating portion 105a is formed on the human-powered transmitter 104 that is separate from the crankshaft 103, the bending stress is increased on the crankshaft 103. It is more difficult to act than the above, and the torque detection ability can be improved as compared with the case where the magnetostrictive generating portion is formed on the crankshaft. Further, since a material suitable for forming the magnetostrictive generation portion 105a on the outer peripheral surface of the human power transmitter 104 can be used, the torque detection ability can be improved by this as well.

Further, the one-way clutch (claw member) 107 provided in the motor drive unit 102 is provided for the following reasons. That is, in the conventional electric assisted bicycle of this type, even if the passenger stops pedaling the pedal 112, the motor 101 is controlled to continue rotating for a while (so-called delay control). In this case, if the one-way clutch 107 is not provided, the auxiliary driving force from the motor 101 is transmitted to the crankshaft 103, and the pedal 112 tries to continue rotating without permission. Therefore, the unidirectional clutch 107 cuts off the auxiliary driving force from the motor 101 so that such a force does not act on the crankshaft 103 and the pedal 112.

By the way, in the motor drive unit 102 provided with the magnetostrictive torque sensor 105, a rotation sensor 115 (see FIG. 16) for detecting the rotation of the crankshaft 103 and the like is provided. The motor drive unit 102 is arranged so as to face the outer peripheral portion of the tubular body (outer portion) 109 engaged with the human power transmission body 104 from the outside. When a rotation detection tooth, a permanent magnet, or the like is fixed to the outer peripheral portion of the tubular body (outer portion) 109 to form a rotation detection tooth, a permanent magnet and a coil are used as the rotation sensor 115. A so-called pickup sensor (magnetic sensor) provided is provided.

JP-A-2009-208710 Japanese Unexamined Patent Publication No. 10-81292

However, in the motor drive unit 102 shown in FIGS. 14 to 16, a permanent magnet or the like is arranged on the rotation sensor 115 or the cylinder (outer portion) 109 in the vicinity of the magnetostrictive torque sensor 105, so that the torque There is a risk that the torque detection capability will decrease due to disturbance factors and noise when detecting (human-powered driving force).

The present invention solves the above problems, and is a motor when the passenger stops pedaling while being able to detect torque by a magnetic distortion type torque sensor and detect rotation of a crankshaft or the like. It is an object of the present invention to provide a motor drive unit and an electrically assisted bicycle capable of maintaining a good torque detection ability without transmitting an auxiliary driving force from the crankshaft.

In order to solve the above problems, the motor drive unit of the present invention is a motor drive unit used for an electrically assisted bicycle capable of traveling by adding an auxiliary drive force generated by a motor to a human power drive force generated by a pedaling force from a pedal. A crank shaft penetrating the unit case constituting the outer shell of the motor drive unit, a tubular human-powered transmitter arranged on the outer periphery of the crank shaft, and deceleration substantially parallel to the crank shaft. A deceleration mechanism having a deceleration gear supported by a gear support shaft, and a rotating shaft supported by a first bearing and a second bearing substantially parallel to the crank shaft, and teeth that mesh with the deceleration gear. The unit case includes a motor provided on the rotating shaft, a control unit having a control board for controlling the motor, and a connecting member for connecting the motor and the control board. It is divided into a plurality of regions by a partition portion, the control board and the crank shaft are arranged in the same region, and the unit case is further arranged in an region where the rotor portion and the stator portion of the motor are arranged. The first bearing and the second bearing are internally provided with a first space to be formed and a second space to be formed in a region where the control substrate and the crank shaft are arranged. Ri inner diameter Do different and, further that the inner diameter of said first bearing and said second bearing having a large diameter, and a inner diameter member and the outside diameter member, the inner diameter member in contact with the rotary shaft.

Motor drive unit.

Further, in the motor drive unit of the present invention, the end portion of the control board on the control board opposite to the crankshaft side is located in a direction away from the crankshaft from the reduction gear support shaft.

Further, in the motor drive unit of the present invention, the control board is arranged in the unit case so that the board surface extends in a direction intersecting the crankshaft.

Further, in the motor drive unit of the present invention, the reduction gear is located in the second space.

Further, in the motor drive unit of the present invention, the inner diameter of the first bearing is larger than the inner diameter of the second bearing, and the first bearing is the second bearing in the axial direction of the rotating shaft. It is arranged at a position closer to the tooth portion.

Further, in the motor drive unit of the present invention, the reduction mechanism further includes a reduction gear support shaft bearing that supports the reduction gear support shaft, and the reduction gear support shaft bearing and the first bearing rotate. It overlaps when viewed in the radial direction of the shaft.

Further, in the motor drive unit of the present invention, the partition portion has a recessed portion in the axial direction of the rotating shaft, and the first bearing is arranged in the recessed portion.

Further, in the motor drive unit of the present invention, at least a part of the reduction gear support shaft bearing overlaps the motor when viewed in the axial direction of the reduction gear support shaft.

Further, in the motor drive unit of the present invention, the second bearing is arranged on one end side of the rotating shaft, the control unit is arranged on the other end side, and the first bearing is arranged in the axial direction of the rotating shaft. It is arranged between the second bearing and the control unit.

Further, the electrically assisted bicycle of the present invention includes the motor drive unit.

With this configuration, the torque can be detected by the magnetostrictive torque sensor, the rotation of the intermediate cylinder or the human-powered transmitter can be detected by the rotation detector, and the rotation of the crankshaft or pedal can be detected. Further, the one-way clutch arranged between the intermediate cylinder and the interlocking body can be configured so that the auxiliary driving force from the motor is not transmitted to the crankshaft when the passenger stops pedaling. .. Further, since an optical sensor is used as a rotation detector for detecting the rotation of the intermediate cylinder or the human-powered transmitter, when detecting torque (human-powered driving force) as in the case of using a magnetic sensor as a rotation detector. It is possible to prevent the torque detection ability from being lowered due to disturbance factors and noise, and the torque can be detected satisfactorily.

Further, the present invention may be characterized in that a rotating body that blocks or reflects the light of the optical sensor is attached at a position corresponding to the rotation detector on the outer periphery of the intermediate cylinder or the human power transmitting body. Here, as a method of detecting the rotation of the crankshaft, it is conceivable to provide the crankshaft with a rotating body that blocks or reflects the light of the optical sensor, and to detect the light radiated to the rotating body. .. However, as in this configuration, by attaching a rotating body that blocks or reflects the light of the optical sensor to the outer periphery of the intermediate cylinder or the human power transmitter, the rotating body that blocks or reflects the light of the optical sensor is cranked. Since it is arranged in a portion having a larger diameter than when it is provided on the shaft, the resolution of the rotation detector can be improved. Further, as a specific example of the rotating body, it is conceivable that the rotating body is composed of a disk or a cylinder having tooth portions formed over the entire circumference, and an emitting portion and a light receiving portion are provided so as to sandwich the tooth portions. In this case, since the disk or cylinder on which the tooth portion is formed is attached to the intermediate cylinder or human power transmitter having a diameter relatively larger than the crank shaft, the disk or cylinder on which the tooth portion is formed is used. , Even if the radial dimension from the inner diameter to the outer diameter is not made too large, more teeth can be formed at a position with a relatively large diameter, and the teeth are formed at a position with a relatively small diameter. It is possible to improve the resolution of the rotation detector as compared with the one used. Further, in order to obtain the same resolution of the rotation detector when the rotating body is attached to the crankshaft, the dimensions in the radial direction from the inner diameter portion to the outer diameter portion of the disk or cylinder having the tooth portion formed therein are determined. It is conceivable to increase the size, but in this case, the disk or cylinder forming the tooth portion may be easily deformed. On the other hand, by attaching the rotating body to the intermediate cylinder or the human-powered transmitter arranged on the outer circumference of the crankshaft, the radial dimension from the inner diameter portion to the outer diameter portion is made too large. Since it is not necessary, the possibility of the rotating body being deformed can be minimized.

Further, in the present invention, as described above, one rotating body that blocks or reflects the light of the optical sensor is attached at a position corresponding to the rotation detector on the outer periphery of the intermediate cylinder or the human power transmitter. The rotation detector may be characterized in that two optical sensors are arranged side by side at positions where the phases of the output signals differ by 90 degrees in the rotation direction of the rotating body. With this configuration, it is possible to detect that the pedal has stopped or rotated in the opposite direction.

Further, the present invention may be characterized in that the interlocking body synthesizes the human-powered driving force transmitted through the human-powered transmitter and the auxiliary driving force from the motor. Alternatively, an auxiliary driving force output wheel body that engages with the endless driving force transmitting body and outputs the auxiliary driving force output from the motor may be provided.

Further, in the present invention, a reduction mechanism having a reduction gear portion and a reduction gear support shaft for supporting the reduction gear portion is provided in the transmission path of the auxiliary driving force, and the reduction gear portion and the reduction gear portion are provided. It may be characterized in that a one-way clutch for cutting the human-powered driving force that does not transmit the human-powered driving force to the motor side is disposed between the gear support shaft.

With this configuration, even when the pedal is pedaled and rotated when the remaining capacity of the battery is exhausted, a one-way clutch for cutting the human-powered driving force arranged between the reduction gear portion and the reduction gear support shaft is provided. As a result, it is not necessary to rotate the reduction gear or the motor, and it is not necessary to apply extra force to the pedal.

Further, in the present invention, the motor, the deceleration mechanism, and the control unit are incorporated in the motor drive unit, the motor and the control unit are overlapped in a side view, and are arranged on opposite sides in the width direction. It may be a feature.

With this configuration, the area (projected area from the lateral direction) of the motor drive unit when viewed from the side can be reduced (can be made compact). Further, since the motor and the control unit are arranged on opposite sides in the width direction of the motor drive unit, the control unit is less likely to be affected by the heat of the motor, and good reliability can be maintained.

According to the present invention, a tubular human-powered transmitter in which a magnetic strain generating portion of a torque sensor for detecting a human-powered driving force is formed on the outer periphery of the crankshaft, and an intermediate cylinder engaged with the human-powered transmitter. By using an optical sensor as a rotation detector to detect the rotation of the intermediate cylinder or the human-powered transmitter, an intermediate cylinder that rotates integrally with the crankshaft without affecting the torque sensor with magnetism. It is possible to easily and surely detect the rotation of the body and the human power transmitter member. Further, it is conceivable that the torque sensor is also used as the rotation detector, but as compared with the case where the torque sensor is also used in this way, the rotation can be detected easily and surely and the control is easy, so that the detection can be performed quickly. There are advantages.

Further, by attaching a rotating body that blocks or reflects the light of the optical sensor at a position corresponding to the rotation detector on the outer circumference of the intermediate cylinder or the human-powered transmitter, the rotation detector has relatively good resolution. Can be obtained. Further, even when a disk or cylinder having teeth formed over the entire circumference is attached to the outer circumference of the intermediate cylinder or the human power transmitter as the rotating body, the radial direction from the inner diameter portion to the outer diameter portion of the rotating body is obtained. Since it is not necessary to increase the size of the tooth portion so much, the possibility of deformation of the tooth portion and the like can be minimized, and good reliability can be maintained.

Further, a reduction mechanism having a reduction gear portion and a reduction gear support shaft for supporting the reduction gear portion is provided in the transmission path of the auxiliary driving force, and the reduction gear portion and the reduction gear support shaft are provided. By arranging a one-way clutch for disconnecting the human-powered driving force that does not transmit the human-powered driving force to the motor side between the two, even if the pedal is pedaled and rotated when the remaining capacity of the battery is exhausted, it is used for deceleration. You don't have to rotate gears or motors, and you don't have to apply extra force to the pedals (so-called drag resistance can be significantly reduced).

Further, the motor, the deceleration 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 arranged on opposite sides in the width direction in a front view (or a plan view). By doing so, the area (projected area from the lateral direction) of the motor drive unit when viewed from the side can be made particularly small (compact) as a uniaxial motor drive unit, and the control unit can control the heat of the motor. It is less susceptible and can maintain good reliability.

Overall side view of the electrically power assisted bicycle according to the embodiment of the present invention Partial notch side view of the electrically power assisted bicycle Side view of the motor drive unit of the electrically power assisted bicycle (drive sprocket is omitted) Plane cross-sectional view of the motor drive unit of the electrically power assisted bicycle (planar cross-sectional view taken along line IV-IV in FIG. 3) Enlarged plan sectional view of the main part of the motor drive unit of the electrically power assisted bicycle Side view of the rotation detector and rotating body of the motor drive unit of the electrically power assisted bicycle The figure for demonstrating the operation of the rotation detector and the rotating body of the motor drive unit. The figure for demonstrating the operation of the rotation detector and the rotating body of the motor drive unit. Enlarged plan sectional view of the motor drive unit of the electrically power assisted bicycle according to another embodiment of the present invention. Partial cutout side view of the electrically power assisted bicycle according to another embodiment of the present invention. Plane cross-sectional view of the motor drive unit of the electrically power assisted bicycle Enlarged plan sectional view of the main part of the motor drive unit of the electrically power assisted bicycle An enlarged plan sectional view of a main part of a motor drive unit in an electrically power assisted bicycle according to still another embodiment of the present invention. Side view of a conventional electrically power assisted bicycle Plane sectional view of the motor drive unit in the conventional electrically power assisted bicycle Cross-sectional view of the main part of the motor drive unit in the conventional electrically power assisted bicycle

Hereinafter, the motor drive unit and the electrically power assisted bicycle according to the 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 the direction in which the electrically power assisted bicycle 1 is mounted in the traveling direction. Further, the configuration of the present invention is not limited to the configuration described below.

1 in FIGS. 1 and 2 is an electrically power assisted bicycle according to an embodiment of the present invention. As shown in FIGS. 1 and 2, the electrically assisted 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, and a seat stay 2f. 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 and the like. A crank 7 and a pedal 8 to which a human-powered driving force consisting of 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 motors including the motor 21. A motor drive unit 20 provided with a control unit 24 (see FIG. 4) for control, a battery 12 composed of a secondary battery for supplying power for driving to the motor 21, and a handle 5 or the like attached to board the vehicle. A driving force output that is attached to a hand operation unit (not shown) that can be operated by a person or the like so as to rotate integrally with the crankshaft 7a in a coaxial center, and outputs a resultant force that is a combination of human-powered driving force and auxiliary driving force. Drive sprocket (also called front sprocket, crank sprocket or front gear) 13 as a wheel and rear sprocket (also called rear gear) as a rear wheel attached to the hub (also called rear hub) 9 of the rear wheel 4. The chain 15 as an endless driving force transmitter wound endlessly over the driving sprocket 13 and the rear sprocket 14 in a rotatable state, and a chain covering the chain 15 and the like from the side. It is equipped with a cover 17 and the like. The battery 12 is an example of a power storage device, and a secondary battery is preferable, but another example of the power storage device may be a capacitor or the like. The crank 7 is composed of a crank arm 7b provided on each of the left and right sides and a crankshaft 7a connecting the left and right crank arms 7b to each other.

As shown in FIGS. 1 and 2, also in this electrically power assisted bicycle 1, the motor drive unit 20 is located at an intermediate position between the front wheels 3 and the rear wheels 4, such as substantially behind the crankshaft 7a (more specifically, an intermediate position). It is located at the bottom of). With such an arrangement, the relatively heavy motor drive unit 20 is arranged at the center of the electrically power assisted bicycle 1 in the front-rear direction, so that the front wheels 3 and the rear wheels 4 can be easily lifted and the traveling path. The vehicle body (frame 2, etc.) of the electrically power assisted bicycle 1 is easy to handle, and the running stability is also good, such that even if there is a step on the bicycle, it can be easily overcome.

FIG. 3 is a side view of the motor drive unit 20 (the drive sprocket 13 is omitted), and FIG. 4 is a plan sectional view of the motor drive unit 20. As shown in FIGS. 3 and 4, the motor drive unit 20 has an outer shell portion and the like formed by a unit case 22 including a motor case 22a, a left side case 22b, and a right side case 22c, and cranks the front portion of the motor drive unit 20. The shaft 7a penetrates left and right. Further, on the outer periphery of the crankshaft 7a, a substantially tubular human power transmission body 28 in which the human power driving force from the crankshaft 7a is transmitted, and an intermediate tubular body 23 in which the human power driving force from the human power transmission body 28 is transmitted. The human-powered driving force from the intermediate cylinder 23 is transmitted via the one-way clutch (one-way clutch for cutting the auxiliary driving force) 30, and the human-powered driving force transmitted via the human-powered transmitter 28 and the like and the motor 21. An interlocking body 29 that functions as a resultant force body that synthesizes the auxiliary driving force of the above is arranged. Further, a reduction mechanism 25 having a reduction gear 36 or the like is arranged in the center of the unit case 22 in the front-rear direction, a motor 21 is arranged on the rear left side in the unit case 22, and a rear right side in the unit case 22. A control printed circuit board 24a provided with electronic components for performing various electrical controls and a control unit 24 having a storage unit for various information are arranged.

Specifically, as shown in FIGS. 4 and 5, the crankshaft 7a is rotatably arranged by bearings 26 and 27 while penetrating the front portion of the motor drive unit 20 to the left and right, and is rotatably arranged on the left side of the crankshaft 7a. A tubular human power transmitter 28 is fitted on the outer periphery of the near portion via a serration portion (or spline portion) 7c in a state of being integrally rotated. A serration portion (or spline portion) 28b is also formed at a portion corresponding to the serration portion (or spline portion) 7c of the crankshaft 7a on the inner circumference of the human power transmitter 28, and the serration portion (or spline portion) of the crankshaft 7a is formed. ) It meshes with 7c.

On the outer peripheral surface of the human power transmitter 28, a magnetostrictive generating portion 31b imparted with magnetic anisotropy is formed, and a coil 31a is arranged on the outer periphery thereof through a constant gap (space), and these magnetostrictions are provided. The magnetostrictive torque sensor (human power detection unit) 31 is composed of the generation unit 31b and the coil 31a. As a result, the human-powered driving force from the crankshaft 7a is transmitted to the human-powered transmission body 28, and the human-powered driving force is detected by the torque sensor 31. Further, in this magnetostrictive torque sensor 31, the magnetostrictive generating portion 31b is formed in a spiral shape forming, for example, +45 degrees and −45 degrees with respect to the axial direction of the human power transmitter 28, and the magnetostrictive body 28 is formed. When the human-powered driving force is transmitted to, the magnetostrictive portion 31b on the surface of the human-powered transmitter 28 is distorted and a portion where the magnetic permeability increases and a portion where the magnetic permeability decreases are generated. Therefore, by measuring the inductance difference of the coil 31a. It is configured to be able to detect the magnitude of torque (human-powered driving force). In this embodiment, it is possible to detect that the crankshaft 7a is rotated in the opposite direction by the above configuration, but the present invention is not limited to this.

The intermediate cylinder 23 is arranged on the outer periphery of the crankshaft 7a adjacent to the right side of the human power transmission body 28 in a rotatable state with respect to the crankshaft 7a, but is the right end portion of the human power transmission body 28. The serration portion (or spline portion) 28a formed on the outer periphery and the serration portion (or spline portion) 23a formed on the inner circumference of the left end portion of the intermediate cylinder 23 are fitted together. In this embodiment, the serration portion (or spline portion) 23a formed on the inner circumference of the left end portion of the intermediate cylinder 23 is fitted to the serration portion (or spline portion) 28a of the human power transmitter 28 from the outside. There is.

Further, as described above, a one-way clutch (one-way clutch for cutting auxiliary driving force) 30 is disposed between the intermediate cylinder 23 and the interlocking body 29, and is intermediate inside the one-way clutch 30. The tubular body 23 is attached, and the interlocking body 29 is attached to the outside of the one-way clutch 30. The interlocking body 29 is arranged on the outer circumference of the crankshaft 7a in a rotatable state with respect to the crankshaft 7a, and an auxiliary driving force from the motor 21 is transmitted. On the other hand, in the one-way clutch 30, the human-powered driving force in the forward direction from the intermediate cylinder 23 is transmitted to the interlocking body 29, but the interlocking body 29
The auxiliary driving force in the forward direction is not transmitted to the crankshaft 7a and the pedal 8 side via the intermediate cylinder 23. That is, even in this electrically assisted bicycle 1, so-called delay control is performed so that the motor 21 continues to rotate for a while even if the passenger stops pedaling 8, but the one-way clutch 30 assists the bicycle. The driving force is cut off to prevent the crankshaft 7a and the pedal 8 from continuing to rotate without permission.

Further, as shown in FIGS. 5 and 6, the motor drive unit 20 detects the rotation of the intermediate cylinder 23, which is a member that rotates integrally with the crankshaft 7a, and by extension, the crankshaft 7a and the pedal 8. Two rotation detectors 10 (10A, 10B) are provided. In this embodiment, two paired optical sensors including an emitting unit 10a and a light receiving unit 10b are arranged side by side in the lateral direction (specifically, the rotation direction of the tooth portion 11b of the rotating body 11 described later) and rotate. The detector 10 (10A, 10B) is configured (see FIGS. 6 to 8). Further, a rotating body 11 for blocking or passing the light of the rotation detector 10 (10A, 10B) is attached to the outer periphery of the left end portion of the intermediate cylinder 23. The rotating body 11 has a substantially tubular shape and a mounting portion 11a attached and fixed to the outer periphery of the left end portion of the intermediate cylinder body 23, and a tooth portion extending in the outer peripheral direction from the left end portion of the mounting portion 11a in a comb-like shape. It has a (light-shielding portion) 11b. Then, the tooth portion 11b and the tooth groove portion (light-transmitting portion) 11c between the tooth portions 11b are provided along the light emission path between the emission portion 10a and the light receiving portion 10b of the rotation detector 10 (10A, 10B). Upon passing through, the rotation detector 10 is configured to detect the rotation speed (rotation amount) of the intermediate cylinder 23, the crankshaft 7a, and the pedal 8. Further, as shown in FIGS. 7 and 8 (in the arrangement of the drawings, the arrangement is reversed from that of FIG. 6), the two rotation detectors 10A and 10B are located at positions where the phases of the output signals are different by 90 degrees. Since the input signal differs depending on the rotation direction of the rotation detectors 10A and 10B, the intermediate cylinder 23, and eventually the crankshaft 7a and the pedal 8 are in the forward and reverse directions based on the input signal. It is also possible to detect each rotation direction of. As shown in FIGS. 4 and 5, in this embodiment, the rotation detector 10 is provided with a rotating body 11 via a support member 18 extending rearward from the inside of the front end portion of the unit case 22. It is attached toward the place.

Further, a large-diameter gear portion 29b for inputting an auxiliary driving force from the motor 21 is integrally formed on the outer periphery of the left side portion of the interlocking body 29, and a driving force output wheel body is formed on the outer periphery of the right end portion of the interlocking body 29. The drive sprocket 13 is fitted, and the interlocking body 29 and the drive sprocket 13 rotate integrally. The crankshaft 7a is rotatably supported by the bearing 27 fitted to the interlocking body 29 via the interlocking body 29. It should be noted that a thin bearing or the like is provided between the interlocking body 29 and the crankshaft 7a, between the intermediate cylinder 23 and the crankshaft 7a, and between the right inner peripheral surface of the human power transmitter 28 and the crankshaft 7a. May be arranged.

As shown in FIG. 4, the rotating shaft 21a and the rotor portion 21b of the motor 21 are rotatably supported by bearings 32 and 33. Further, the rotating shaft 21a of the motor 21 is projected to the right side, and the tooth portion 21c is formed on the outer periphery of the protruding portion. The reduction gear 25 is configured to amplify the rotational torque (auxiliary driving force) of the motor 21 and transmit it to the large-diameter gear portion 29b of the interlocking body 29 via the reduction gear 36. Here, the support shaft of the reduction gear 36 (reduction gear support shaft) is an example of a reduction gear small diameter support shaft portion (reduction gear support shaft) rotatably supported by bearings 34 and 35. (Simply abbreviated as small diameter support shaft) 36a and a larger diameter reduction gear large diameter support shaft (another example of the reduction gear support shaft, hereinafter simply abbreviated as large diameter support shaft) 36b and 36b are integrally formed. Further, on the outer circumference of the small diameter support shaft portion 36a, a reduction gear portion 36c (an example of a reduction gear portion, hereinafter simply abbreviated as a small diameter gear portion) 36c, which is separate from the small diameter support shaft portion 36a, is press-fitted or It is assembled so as to rotate integrally via a serration part (or a spline part) or the like. Then, the small-diameter gear portion 36c is meshed with the large-diameter gear portion 29b of the interlocking body 29. On the other hand, a deceleration large-diameter gear portion (another example of the deceleration gear portion, hereinafter simply abbreviated as the large-diameter gear portion) 36d is arranged on the outer periphery of the large-diameter support shaft portion 36b of the reduction gear 36. At the same time, the large-diameter gear portion 36d is meshed with the tooth portion 21c of the rotating shaft 21a of the motor 21, but there is a gap 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 the human-powered driving force is provided so that the rotational driving force from the interlocking body 29 is not transmitted to the motor 21 side.

In this one-way clutch 37, the inner peripheral portion of the large-diameter gear portion 36d of the reduction gear 36 based on the motor output (auxiliary driving force) faces the one-way clutch 37, such that a certain amount of auxiliary driving force is output during traveling. When the drive sprocket 13 rotates in a direction that advances relative to the outer peripheral portion of the large-diameter support shaft portion 36b (that is, the number of rotations of the inner circumference of the large-diameter gear portion 36d of the reduction gear 36 in the forward direction). However, when it is larger than the number of rotations of the outer circumference of the large-diameter support shaft portion 36b facing this in the forward direction), the auxiliary driving force transmitted to the large-diameter gear portion 36d of the reduction gear 36 is directly increased. It operates so as to transmit to the diameter support shaft portion 36b. Then, the auxiliary driving force is transmitted to the large-diameter gear portion 29b of the interlocking body 29 via the small-diameter support shaft portion 36a and the small-diameter tooth portion 36c. As a result, in the interlocking body 29, the human-powered driving force and the auxiliary driving force are combined, and the combined combined force is transmitted from the driving sprocket 13 as the driving force output wheel body to the rear wheel 4 via the chain 15. Be transmitted.

On the other hand, when the remaining capacity of the battery 12 is exhausted and the pedal 8 is pedaled 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 36 based on the motor output (auxiliary driving force) When the inner peripheral portion rotates in the direction opposite to the direction in which the drive sprocket 13 is moved forward relative to the outer peripheral portion of the large-diameter support shaft portion 36b facing the large-diameter support shaft portion 36b (the large-diameter gear portion of the reduction gear 36). When the rotation speed of the inner circumference of 36d in the forward direction is smaller than the rotation speed of the outer circumference of the large diameter support shaft portion 36b facing the shaft in the forward direction), the large diameter gear portion 36d of the reduction gear 36 The auxiliary driving force transmitted to the above is disengaged by the one-way clutch 37 and is not transmitted to the large-diameter support shaft portion 36b.

As a result, when the remaining capacity of the battery 12 is exhausted and the pedal 8 is pedaled 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 are driven by human power. The support shaft portion 36b is rotated, but the large-diameter gear portion 36d, the rotating shaft 21a of the motor 21, and the rotor portion 21b are not rotated.

In the above configuration, when the pedal 8 is stepped on during forward traveling, the human power driving force based on the pedaling force applied to the pedal 8 is transmitted from the crankshaft 7a to the human power transmission body 28, the intermediate cylinder 23, and the interlocking body 29, and the human power is transmitted. The driving force is detected by the torque sensor 31 provided on the human power transmission body 28. Then, the auxiliary driving force corresponding to the human-powered driving force is transmitted to the interlocking body 29 via the reduction gear 36 of the deceleration mechanism 25, and the resultant force combined by the interlocking body 29 is transmitted from the drive sprocket 13 to the chain 15. It is transmitted to the rear wheel 4 via the rear wheel 4. As a result, by adding the auxiliary driving force (assisting force) of the motor 21 corresponding to the human-powered driving force, it is possible to travel easily even on an uphill or the like.

On the other hand, when the passenger stops pedaling the pedal 8 during traveling, the rotation of the crankshaft 7a and the intermediate cylinder 23 is also stopped accordingly, so that this stopped state is detected by the rotation detector 10 and the motor 21 Is stopped or braked. As described above, when the passenger stops pedaling the pedal 8 during traveling, the motor 21 is immediately stopped or braked, so that the motor 21 is unnecessarily driven and the consumption of the battery 12 can be suppressed.

Further, according to the above configuration, by using the optical sensor as the rotation detector 10 (10A, 10B), the rotation of the intermediate cylinder 23 is easily and surely detected without affecting the torque sensor 31 by magnetism. can do. That is, when a magnetic sensor is separately provided as the rotation detector 10 and a magnet is embedded in a part of the intermediate cylinder or a magnetic sensor having a magnet is used, the magnetic field generated by the magnetostriction generating unit 31b is used. There is a risk that the torque detection capability will be reduced due to noise during torque detection, such as fluctuations in the torque. On the other hand, since the optical sensor is used as the rotation detector 10, the rotation of the intermediate cylinder 23 can be easily and surely detected while the torque detecting ability is well maintained. Further, by using an optical sensor as the rotation detector 10, the rotation can be easily and surely detected and the control is easy, so that the rotation can be detected quickly, and the rotation of the pedal 8 and the crankshaft 7a is stopped or reversed. There is also an advantage that the motor 21 can be stopped quickly by quickly detecting the above.

Further, in the above configuration, the rotating body 11 is attached to the outer circumference of the intermediate cylinder 23. With this configuration, since the intermediate cylinder 23 is arranged on the outer periphery of the crankshaft 7a, the rotating body 11 is arranged on a portion having a larger diameter than when the rotating body 11 is provided on the crankshaft 7a. Therefore, even when the rotating body 11 having the same radial height is assembled, more teeth 11b can be formed in the rotating body 11 and the rotation detector 10 can detect the rotation without any trouble. The resolution of the detector 10 can be improved.

Further, when the rotation detector 10 composed of an optical sensor is attached to the crankshaft 7a and the same resolution of the rotation detector 10 is to be obtained, a disk or the like having a tooth portion is formed from the inner diameter portion to the outer diameter portion. It is conceivable to increase the radial dimension, but in this case, the disk or cylinder forming the tooth portion may be easily deformed. On the other hand, as described above, by attaching the rotating body 11 to the intermediate cylinder body 23 arranged on the outer circumference of the crankshaft 7a, the rotating body 11 is attached in the radial direction from the inner diameter portion to the outer diameter portion. It is not necessary to increase the size so much, and the possibility that the tooth portion 11b of the rotating body 11 is deformed can be minimized.

Further, instead of attaching the rotating body 11 to the intermediate cylinder 23, as shown in FIG. 9, it may be attached to the human power transmission body 28 arranged on the outer periphery of the crankshaft 7a. According to this configuration, the diameter of the mounting portion of the rotating body 11 is slightly smaller than that of the intermediate cylinder 23, so that the resolution may be slightly lowered, but the human-powered transmitter 28 also rotates integrally with the crankshaft 7a. Therefore, the rotation of the human power transmitter 28, and thus the crankshaft 7a and the pedal 8 can be detected satisfactorily. When the rotating body 11 is attached to the intermediate cylinder 23, the intermediate cylinder 23 is easily affected by vibration from the one-way clutch 30 for cutting the auxiliary driving force, but the rotating body 11 is a human-powered transmitter. When attached to 28, there is an advantage that it is not easily affected by vibration from the one-way clutch 30.

Further, as a method of attaching the rotating body 11 to the human power transmission body 28, there is a method of adhesion or press-fitting, but when the rotating body 11 is press-fitted into the human power transmission body 28 and assembled, the pressing force is input to the human power transmission body 28. The resulting distortion may occur, which may adversely affect the torque sensor 31. On the other hand, when the rotating body 11 is attached to the intermediate cylinder 23, such a problem does not occur, so that the rotating body 11 can be easily and surely attached to the intermediate cylinder 23 and to the torque sensor 31. Can be installed and fixed without adverse effects.

In the above embodiment, the case where the rotating body 11 having the tooth portion 11b that blocks light is provided and the light passing through the tooth groove portion 11c between the tooth portions 11b is detected is described. For example, a similar rotating body may be provided and a light receiving unit may be provided at a position where light is reflected, and the rotating position and the number of rotations may be detected by inputting the reflected light.

Further, in the above configuration, a rotation detector 10 for detecting the rotation of the interlocking body 29, the human power transmission body 28 and the crankshaft 7a is provided, and the interlocking body 29, the human power transmission body 28 and the crankshaft 7a are positive by the control unit 24. When it is detected that the bicycle is rotating in the direction (the direction in which the electrically assisted bicycle 1 moves forward), the bicycle may be temporarily relaxed or the pedal 8 may be in the top dead center or bottom dead center position. Even if the torque fluctuates due to a temporary weakening of the stepping force, the control may be performed so as to suppress the fluctuation of the auxiliary driving force. According to this configuration, it is possible to suppress fluctuations in the auxiliary driving force during traveling, and it is possible to improve the riding comfort.

Further, in the above configuration, the small-diameter gear portion 36c and the large-diameter gear portion 36d as a plurality of reduction gear portions, and these small-diameter gear portions 36c and The reduction gear 36 of the reduction mechanism 25 having the small diameter support shaft portion 36a and the large diameter support shaft portion 36b as the reduction gear support shaft for supporting the large diameter gear portion 36d is arranged. Then, in this embodiment, a one-way clutch for cutting the human-powered driving force that does not transmit the human-powered driving force from the interlocking 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 arranged.

As a result, when the remaining capacity of the battery 12 is exhausted and the pedal 8 is pedaled 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 are driven by human power. Although the support shaft portion 36b is rotated, the large-diameter gear portion 36d, the rotating shaft 21a of the motor 21 and the rotor portion 21b are not rotated, and it is not necessary to apply an extra force to the pedal 8 (so-called drag resistance is extremely reduced). be able to).

Further, in the present embodiment, as shown in FIG. 3, the motor 21 and the control unit 24 are arranged so as to substantially overlap each other when viewed from the side. As a result, the area of the motor drive unit 20 when viewed from the side (projected area from the lateral direction) is output from one axis (the drive sprocket 13 in this embodiment) of the human-powered driving force and the auxiliary driving force. There is an advantage that the so-called uniaxial motor drive unit 20 can be made smaller (compactified). The motor 21 and the control unit 24 are arranged on the opposite side in the width direction in the motor drive unit 20 in front view or plan view (the motor 21 is arranged on the left side and the control unit 24 is arranged on the right side). ). As a result, the control unit 24 is less likely to be affected by the heat of the motor 21, and good reliability can be maintained.

In the above embodiment, the case where the one-way clutch 37 for cutting the human-powered driving force is arranged between the large-diameter gear portion 36d and the large-diameter support shaft portion 36b has been described, but instead of this, human power is used. A one-way clutch 37 for cutting the driving force may be arranged between the small diameter gear portion 36c and the small diameter support shaft portion 36a.

Further, in the above embodiment, the case where the electrically assisted bicycle 1 includes a so-called uniaxial motor drive unit 20 that outputs a human-powered driving force and an auxiliary driving force from one axis has been described. Not limited. In the electrically assisted bicycle 40 shown in FIG. 10, as shown in FIGS. 11 to 13, the motor 21 is used separately from the drive sprocket 13 as the human-powered driving force output wheel body arranged at one end of the crankshaft 7a. A motor drive unit 50, which is also called a so-called biaxial type, is provided with an auxiliary drive force output sprocket 51 as an auxiliary drive force output wheel body that outputs an auxiliary drive force. The motor drive unit 50 is provided with a rotation detector 10 including an optical sensor that detects the rotation of the intermediate cylinder 23 or the human power transmitter 28 that rotates integrally with the crankshaft 7a.

As shown in FIGS. 11 and 12, in this embodiment, the auxiliary driving force from the motor 21 is output from the auxiliary driving force output sprocket 51 via the reduction mechanism 25, and the auxiliary driving force is the endless driving force. It is synthesized by the chain 15 as a transmitter and transmitted to the rear wheels 4. Then, as shown in FIGS. 12 and 13, the rotating body 11 is attached to the intermediate cylinder 23 and the human power transmitter 28, and the rotation detector 10 including an optical sensor attaches the rotating body 11 to the intermediate cylinder 23 and the human power transmission body 28. It is configured to detect the rotation of the 23 or the human power transmitter 28, and thus the rotation of the crankshaft 7a and the pedal 8. The same action and effect as those of the above-described embodiment can also be obtained by this embodiment.

The present invention is applicable to various electrically assisted bicycles that can travel by adding an auxiliary driving force generated by a motor to a human-powered driving force generated by pedaling force from a pedal.

Claims (12)

It is a motor drive unit used for electrically power assisted bicycles that can run by adding the auxiliary drive force generated by the motor to the human power drive force generated by the pedaling force from the pedal.
A crankshaft that penetrates the unit case that constitutes the outer shell of the motor drive unit,
A tubular human-powered transmitter arranged on the outer circumference of the crankshaft,
A reduction mechanism having a reduction gear supported by a reduction gear support shaft substantially parallel to the crankshaft, and a reduction mechanism.
A motor having a rotating shaft supported substantially parallel to the crankshaft by a first bearing and a second bearing, and a tooth portion that meshes with the reduction gear is provided on the rotating shaft.
A control unit having a control board for controlling the motor,
A connecting member for connecting the motor and the control board is provided.
The inside of the unit case is divided into a plurality of areas by a partition portion, and the control board and the crankshaft are arranged in the same area.
The unit case is further formed in a first space formed in a region where a rotor portion and a stator portion of the motor are arranged, and a second space formed in a region where the control board and the crankshaft are arranged. With the space inside,
Wherein Ri inner diameter Do different from the first bearing and the second bearing,
Further, the first bearing and the second bearing having a large inner diameter have an inner diameter member and an outer diameter member, and the inner diameter member is a motor drive unit in contact with the rotating shaft . A rotation detector for detecting the rotation of the crankshaft is further arranged in the region where the control board and the crankshaft are arranged.
The motor drive unit according to claim 1. The motor drive unit according to claim 1 or 2 , wherein the end portion of the control board on the control board opposite to the crankshaft side is located in a direction away from the crankshaft from the reduction gear support shaft. .. The motor drive unit according to claim 1 to 3 , wherein the control board is arranged in the unit case so that the board surface extends in a direction intersecting the crankshaft. The motor drive unit according to any one of claims 1 to 4 , wherein the reduction gear is located in the second space. The inner diameter of the first bearing is larger than the inner diameter of the second bearing, and the first bearing is arranged at a position closer to the tooth portion than the second bearing in the axial direction of the rotating shaft. The motor drive unit according to any one of claims 1 to 5 , which is provided. The reduction mechanism further includes a reduction gear support shaft bearing that supports the reduction gear support shaft.
The motor drive unit according to claim 6 , wherein the reduction gear support shaft bearing and the first bearing overlap each other in the radial direction of the rotating shaft. The first dividing portion has a recess recessed in the axial direction of the rotating shaft.
The motor drive unit according to claim 7 , wherein the first bearing is arranged in the recess. The motor drive unit according to claim 7 or 8 , wherein the reduction gear support shaft bearing is at least partially overlapped with the motor when viewed in the axial direction of the reduction gear support shaft. The motor drive unit according to any one of claims 1 to 9 , wherein the first bearing and the second bearing are arranged on one end side of the rotating shaft in the axial direction with respect to the control unit. Further provided with a driving force output wheel body that is coaxial with the crank and outputs a resultant force that is a combination of the human-powered driving force and the auxiliary driving force.
The motor drive unit according to any one of claims 1 to 10. An electrically assisted bicycle including the motor drive unit according to any one of claims 1 to 11 .

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