WO2019103022A1

WO2019103022A1 - Drive unit of electric assist bicycle, and electric assist bicycle

Info

Publication number: WO2019103022A1
Application number: PCT/JP2018/042920
Authority: WO
Inventors: 将史川上
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2017-11-24
Filing date: 2018-11-21
Publication date: 2019-05-31
Also published as: CN111372841A; CN111372841B; DE112018006005T5; JPWO2019103022A1; JP2024028573A; JP7454790B2

Abstract

Provided are a small drive unit in which an area around a crankshaft thereof can be minimized in size, and an electric assist bicycle provided with this drive unit. A drive unit 20 equipped with a motor is disposed in a middle position between a front wheel and a rear wheel. A crankshaft 7a and a motor 21 are arranged along mutually different axes in the drive unit 20. A substrate 24 is disposed inside the drive unit 20. When the drive unit 20 is viewed from a side along the crankshaft 7a, the substrate 24 is disposed to have a part overlapping a stator 21c of the motor 21.

Description

Drive unit for electrically assisted bicycle and electrically assisted bicycle

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

It has a battery as a power supply and a drive unit provided with a motor fed from the battery, and by adding an auxiliary drive force (assist force) of the drive unit to a human drive force by a pedal force applied to a pedal, An electrically assisted bicycle (also referred to as an electrically powered bicycle) that can easily travel even on an uphill or the like is already widely known.

Among such electrically assisted bicycles, there is one in which a drive unit having a motor or the like built therein is disposed at a location where a crankshaft is provided. In such an arrangement of the electrically assisted bicycle, the drive unit having a relatively large weight is disposed at a low position at the center in the front-rear direction of the electrically assisted bicycle (that is, in the middle between the front and rear wheels). Therefore, the motor-assisted bicycle of this arrangement is easier to lift the front wheels and the rear wheels compared to those in which the motor is built in the front wheel hub or the rear wheel hub, and even if there are steps on the traveling path There is an advantage that the vehicle can be easily maneuvered, and the running stability is also good.

The drive unit incorporates a substrate (also referred to as a main substrate or a drive substrate) on which various electronic components for driving or controlling the motor are mounted. This substrate has a relatively large area because large electronic components such as FETs and a relatively large number of electronic components are mounted. Further, as shown in, for example, Japanese Patent Application Laid-Open No. 2016-203735 etc., this substrate is disposed around the crankshaft in a side view (viewed in the direction of the crankshaft center).

By the way, in recent years, in the electrically assisted bicycle, there may be a case where a distance from the crankshaft to the rear wheel or the front wheel is not much different from that of a general bicycle and one that can exhibit the function as a bicycle well. However, if a drive unit in which a substrate is arranged around the crankshaft is adopted, a larger area is required around the crankshaft as the substrate becomes larger, and the drive unit becomes larger as well, and the layout of the drive unit is devised. However, there is a problem that the distance from the crankshaft to the rear wheel axle is considerably long.

The present invention solves the above-mentioned problems, and it is possible to miniaturize, for example, the area around the crankshaft can be minimized, and drive of an electrically assisted bicycle capable of exhibiting the function as a bicycle well. It is an object of the present invention to provide a unit and a motor-assisted bicycle provided with the drive unit.

In order to solve the above problems, the drive unit of the electrically assisted bicycle according to the present invention is attached to an electrically assisted bicycle capable of traveling by applying an auxiliary driving force by a motor to a manual driving force by a pedal force from a pedal. A drive unit of a motor-assisted bicycle including: a mounting portion attached to an intermediate position between a front wheel and a rear wheel of the motor-assisted bicycle, and a crankshaft through which a manual drive force from the pedal is transmitted And a driving force output wheel body for outputting a driving force, wherein the crankshaft and the motor are disposed at mutually different axial centers, and a substrate is disposed inside the driving unit. The substrate is characterized in that the substrate is arranged to have a portion overlapping the stator of the motor when viewed from the side along the crankshaft. A plurality of substrates may be provided inside the drive unit, in which case the substrate having a portion overlapping the stator of the motor is the substrate of the largest area of the plurality of substrates.

According to this configuration, since the substrate is arranged to have a portion overlapping the stator of the motor when viewed from the side, a substrate with a sufficiently large area can be adopted as the substrate. In addition, even when a substrate (separate substrate or part of the substrate) is disposed also around the crankshaft, the area of the substrate around the crankshaft can be reduced, so the layout of the drive unit should be devised. Therefore, the distance from the crankshaft to the rear wheel axle can be made closer to that of a general bicycle.

It is preferable that the substrates be disposed so as to overlap in a half or more area of the stator of the motor in a side view. In addition, in a side view, the substrate may be disposed so as to overlap from the region where the stator of the motor is disposed to the region around the crankshaft.

In addition, a motor rotation sensor for reading the rotation of the motor and a crankshaft rotation sensor for reading the rotation of the crankshaft may be attached to the substrate, which makes it possible to reduce the number of parts and the time for mounting.

In addition, the rotation of the motor is transmitted to the driving force output wheel body that outputs the driving force via the two-step reduction mechanism, and the ratio of the number of rotations of the motor to the number of rotations of the driving force output wheel body Preferably, the reduction ratio is 30 to 37. Moreover, it is suitable that the minimum radius around a crankshaft is 50 mm or less.

Further, the electrically assisted bicycle including the drive unit of the present invention is provided with a reduction gear mechanism having a plurality of pairs of reduction gears, and the reduction gear mechanism includes an intermediate shaft disposed parallel to the crankshaft and the intermediate shaft. A plurality of intermediate shaft reduction gears provided, a crankshaft reduction gear rotatably disposed on the outer periphery of the crankshaft, to which a manual drive force and an auxiliary drive force are transmitted, and a motor shaft provided on a motor shaft And an intermediate shaft bearing rotatably supporting the intermediate shaft, the intermediate shaft being disposed between the crankshaft and the motor shaft with respect to the front-rear direction, and the crank When the motor shaft is disposed forward of the shaft, it is disposed below the straight line connecting the crankshaft and the motor shaft, and when the motor shaft is disposed rearward of the crankshaft, the intermediate shaft Axis is Kura Characterized in that it is disposed above the line connecting the click shaft and the motor shaft.

Also, in this case, in a state in which the electric assist bicycle travels in the direction of travel and viewed from the right side, with respect to a line connecting the shaft center of the crankshaft and the shaft center of the motor shaft, the shaft center of the crankshaft and the intermediate shaft It is preferable to arrange the crankshaft, the motor shaft and the intermediate shaft so that the crossing angle of the line connecting the shaft center with the shaft center is within 30 degrees to 70 degrees in the clockwise direction.

In this configuration, when the reduction gears mesh with each other, a reaction force is generated, and a large reaction force acts on the intermediate shaft. Therefore, at least one of the intermediate shaft bearings rotatably supporting the intermediate shaft is subjected to a large force. As a result, the drive unit tends to be large (in particular, the widthwise dimension of the drive unit tends to be large).

However, according to the above configuration (arrangement configuration of the crankshaft, the motor shaft and the intermediate shaft), the reaction forces to the intermediate shaft generated when the reduction gears mesh with each other cancel each other and minimize. Can. As a result, the intermediate shaft bearing can be downsized (downsized in the width direction or the radial direction), and in turn, the drive unit can be downsized (for example, the drive unit can be downsized in the width direction or the like).

Further, a drive power supply device for an electrically assisted bicycle according to the present invention includes the drive unit and a storage battery for supplying power to the drive unit.

The electrically assisted bicycle according to the present invention is characterized by comprising the drive unit for the electrically assisted bicycle according to any one of the above or the drive power feeding device.

According to the present invention, by arranging the substrate so as to have a portion overlapping the stator of the motor in a side view, the substrate having a sufficiently large area can be adopted as the substrate, and the substrate is also provided around the crankshaft. Even when (a separate substrate or part of the substrate) is disposed, the area of the substrate around the crankshaft can be reduced. Thereby, the distance from the crankshaft to the axle of the rear wheel can be made closer to a general bicycle by devising the arrangement of the drive unit. Further, by arranging the substrate so as to have a portion overlapping the stator of the motor in a side view, there is also a so-called sound insulation effect in which the substrate can block the sound generated by the motor.

Further, according to the present invention, the rotation of the motor is transmitted to the driving force output wheel mounted on the drive unit via the two-step reduction mechanism, and the number of rotations of the driving force output wheel is By configuring the reduction gear ratio, which is the ratio of the number of rotations of the motor to the gear ratio, to be 30 to 37, a reduction gear having a relatively small diameter can be used as the reduction gear coaxial with the crankshaft. It is possible to reduce the diameter (radius and diameter) around the crankshaft. Thereby, the distance from the crankshaft to the axle of the rear wheel can be made closer to a general bicycle (for example, a so-called sport bicycle).

In addition, by setting the minimum radius around the crankshaft (around the crankshaft) of the drive unit to 50 mm or less, the distance from the crankshaft to the axle of the rear wheel can be a general bicycle (for example, a so-called sports bicycle) It is possible to get closer to

Further, according to the present invention, when the intermediate shaft is disposed between the crank shaft and the motor shaft in the front-rear direction and the motor shaft is disposed forward of the crank shaft, the crank shaft When the motor shaft is disposed rearward of the straight line connecting the motor shaft and the motor shaft is disposed rearward of the crankshaft, the intermediate shaft is disposed above the straight line connecting the crankshaft and the motor shaft, or Furthermore, in a state in which the drive unit is viewed from the right side in the forward direction, the axial center of the crankshaft and the axial center of the intermediate shaft with respect to a line connecting the axial center of the crankshaft and the axial center of the motor shaft The crankshaft, the motor shaft, and the intermediate shaft are arranged such that the crossing angle of the connecting line is within 30 degrees to 70 degrees in the clockwise direction. With this configuration, the reaction forces on the intermediate shaft generated when the reduction gears mesh with each other can be suppressed so as to mutually cancel each other and be minimized, and the intermediate shaft bearing and hence the drive unit can be miniaturized (for example, The drive unit can be miniaturized in the width direction or the like). As a result, it is possible to bring the distance between the crank arms closer to a general bicycle (for example, a so-called sport type bicycle).

Overall left side view of the electrically assisted bicycle to which the drive unit according to the embodiment of the present invention is attached Plan sectional drawing of the drive unit of the electrically-assisted bicycle of the embodiment (1st Embodiment) Simplified right side sectional view of the drive unit A plan sectional view of a drive unit according to a first modification of the first embodiment of the present invention A plan sectional view of a drive unit according to a second modification of the first embodiment of the present invention The high-speed stage clutch is a disconnection state in the planar sectional view of the drive unit of the electrically-assisted bicycle which concerns on the 2nd Embodiment of this invention The high-speed stage clutch is in the connected state in a simplified right side cross-sectional view of the same drive unit The high-speed stage clutch is not connected in the main part enlarged plane sectional view of the intermediate shaft of the drive unit, and the vicinity of it The high-speed stage clutch is in the connected state in a plan sectional view of the drive unit The high-speed stage clutch is in the connected state in the main part enlarged plan sectional view of the intermediate shaft of the drive unit and the vicinity thereof A simplified plan view showing a motor shaft, an intermediate shaft, a crankshaft, and a reduction gear assembled to these shafts in a drive unit of a motor-assisted bicycle according to a first embodiment of the present invention Simplified right side sectional view showing force vector (reaction force) acting on the contact portion of the gear of the drive unit Simplified right side sectional view showing the state where the force vector (reaction force) is acting on the intermediate shaft of the drive unit A plan sectional view of a drive unit of an electrically assisted bicycle according to a third embodiment of the present invention Simplified right side sectional view showing force vector (reaction force) acting on the contact portion of the gear of the drive unit Simplified right side cross-sectional view showing the state where the force vector (reaction force) is acting on the intermediate shaft of the drive unit Right side cross-sectional view of a drive unit according to a modification of the third embodiment of the present invention

First Embodiment
Hereinafter, a drive unit of an electrically assisted bicycle according to an embodiment of the present invention and an electrically assisted bicycle to which the drive unit is attached will be described based on the drawings. In addition, the left-right direction and the front-back direction in the following description mean the direction in the state where a person boarded the said electrically assisted bicycle 1 toward the advancing direction. Further, the configuration of the present invention is not limited to the configuration described below.

Reference numeral 1 in FIG. 1 denotes an electrically assisted bicycle to which a drive unit according to the embodiment of the present invention is attached. As shown in FIG. 1, the electrically assisted bicycle 1 comprises a metal frame 2 comprising a head pipe 2a, a front fork 2b, an upper pipe 2c, a lower pipe 2g, an upright pipe 2d, a chain stay 2e, a seat stay 2f and the like. , A front wheel 3 rotatably mounted at the lower end of the front fork 2b, a rear wheel 4 rotatably mounted at the rear end of the chain stay 2e, a steering wheel 5 for changing the direction of the front wheel 3, and a passenger , A crank 7 and a pedal 8 to which a human drive force consisting of pedaling force is applied, an electric motor 21 (see also FIG. 2) as a drive source for generating an auxiliary drive force (assist force) A drive unit (drive unit device) 20 provided with a control unit and the like for controlling various electrical components including the drive unit 20 and a drive power supply to the motor 21 A hand-operated operation unit 18 attached to the battery 12 consisting of a secondary battery, a handle 5 or the like, allowing a passenger or the like to operate, and capable of changing settings of the power supply of the motor-assisted bicycle 1 and traveling mode etc. Drive sprocket mounted as a drive force output wheel body that is mounted so as to rotate integrally with 7a coaxially and output the resultant force of manual drive force and auxiliary drive force combined (also called front sprocket, crank sprocket or front gear) 13) and a rear sprocket (also sometimes referred to as a rear gear) 14 as a rear wheel body attached to a hub (also referred to as a rear hub) 9 of the rear wheel 4, a drive sprocket 13 and the rear sprocket 14 And a chain 15 as an endless driving force transmission body wound endlessly in a possible state. Further, a drive power supply device (drive unit module) is configured by the drive unit 20 and the battery 12.

The motor-assisted bicycle 1 can travel by adding the auxiliary driving force generated by the motor 21 to the manual driving force by the stepping force from the pedal 8 and the resultant force obtained by adding the auxiliary driving force to the manual driving force is the driving sprocket 13. Is transmitted to the rear wheel 4 via the chain 15 and the rear sprocket 14 or the like.

The battery 12 is an example of a storage battery, and a secondary battery is preferable, but the storage battery may be a capacitor or the like. The crank 7 is composed of a crank arm 7b provided respectively on the left and right and a crankshaft 7a connecting the left and right crank arms 7b, and the pedal 8 is rotatably attached to the end of the crank arm 7b.

As shown in FIG. 1, in the electrically assisted bicycle 1, the drive unit 20 is disposed at an intermediate position between the front wheel 3 and the rear wheel 4, more specifically, at a location where the crankshaft 7 a passes through. Then, with such an arrangement configuration, the drive unit 20 with a relatively large weight is disposed at the center of the power-assisted bicycle 1 in the front-rear direction. As a result, the front wheels 3 and rear wheels 4 can be easily lifted, and even if there is a step on the traveling path, the vehicle body (frame 2 etc.) of the electrically assisted bicycle 1 can be well managed. Sex is also considered good.

As shown in FIG. 2, the drive unit 20 has an outer shell portion and the like formed by unit cases 22 including first to third cases 22a to 22c, and the drive unit 20 (in this embodiment, a rear portion of the drive unit 20). The crankshaft 7a passes through the crankshaft insertion area 16) provided on the left and right. Further, the unit case 22 is integrally formed with a mounting portion 22d for mounting the drive unit 20 at an intermediate position between the front wheel and the rear wheel in the electrically assisted bicycle. Further, a substantially cylindrical human power transmitting body 28 to which a human power driving force from the crankshaft 7a is transmitted to the outer periphery of the crankshaft 7a, and an interlocking cylindrical body 23 to which the human power driving force from the human power transmitting body 28 is transmitted; The manual drive force from the interlocking cylinder 23 is transmitted through the one-way clutch (one-way clutch for auxiliary drive force) 30 or the like, and the resultant force combining the manual drive force and the auxiliary drive force from the motor 21. And a resultant force transmitting body 29 for transmitting the driving sprocket 13 to the driving sprocket 13.

Further, in the unit case 22 of the drive unit 20, a decelerating mechanism 25 for decelerating the rotation of the motor 21 and transmitting it to the resultant force transmitting body 29 side (in this embodiment, the intermediate shaft 40), and an auxiliary driving force (assist force) A motor 21 as a driving source is disposed, and a substrate (also referred to as a driving substrate or a main substrate) 24 provided with electronic components for performing various electrical controls is also disposed. A control unit is configured by the substrate 24 and the electronic component (FET (field effect transistor) 24a, a capacitor, a microcomputer, etc.) mounted on the substrate. As shown in FIGS. 2 and 3, the axial center of the rotation shaft 21a of the motor 21, the axial center of the crankshaft 7a, and the axial center of the intermediate shaft 40 described later are different in position from each other. Further, in this embodiment, the rotary shaft 21a, the intermediate shaft 40, and the crankshaft 7a of the motor 21 are disposed sequentially from the front, and the intermediate shaft 40 is disposed below the straight line connecting the crankshaft 7a and the motor shaft 21a. ing. Further, in the drive unit 20 (more specifically, in the unit case 22 of the drive unit 20), a portion excluding the both end portions of the crankshaft 7a, the human power transmission body 28, the interlocking cylindrical body 23, the resultant force transmission body 29, the speed reduction mechanism 25, A motor 21, a torque sensor 31 described later, a rotation detector 11, a rotation detector (rotation sensor) 10 and the like are provided. Then, a manual drive force and an auxiliary drive force are combined in the drive unit 20, and this combined resultant force is a drive sprocket provided outside the drive unit 20 (more specifically, outside the unit case 22 of the drive unit 20). It is comprised so that it may be output from 13.

The drive unit 20 will be described in more detail. As shown in FIGS. 2 and 3, the crankshaft 7 a is rotatably disposed by bearings (crankshaft bearings) 26 and 27 in a state in which the rear portion of the drive unit 20 penetrates left and right. A cylindrical human power transmitter 28 is fitted on the outer periphery of the left side portion of the crankshaft 7a via the serration portion (or spline portion) 7c so as to rotate integrally with the crankshaft 7a. . A serration portion (or spline portion) 28b is also formed at a position corresponding to the serration portion (or spline portion) 7c of the crankshaft 7a in the inner periphery of the human power transmission body 28, and the serration portion (or spline portion) of the crankshaft 7a ) 7c is engaged.

A magnetostriction generating portion 31b to which magnetic anisotropy is imparted is formed on the outer peripheral surface of the human power transmitting body 28, and a coil 31a is disposed on the outer periphery via a fixed gap (space). A magnetostrictive torque sensor (human power detection unit) 31 is configured by the generation unit 31 b and the coil 31 a. Thus, the human drive force from the crankshaft 7a is transmitted to the human power transmitter 28, and the torque sensor 31 detects the human drive force. Further, in the magnetostrictive torque sensor 31, the magnetostriction generating portion 31b is formed in a spiral shape that forms, for example, +45 degrees and -45 degrees with respect to the axial center direction of the human power transmission body 28. Then, when the human driving force is transmitted to the human power transmitting body 28, distortion occurs in the magnetostriction generating portion 31b of the surface of the human power transmitting body 28 to generate an increase portion and a decrease portion of the magnetic permeability. By measuring the difference in inductance, the magnitude of the torque (human driving force) can be detected.

The interlocking cylindrical body 23 is disposed at a position adjacent to the right side of the human power transmission body 28 on the outer periphery of the crankshaft 7 a in a rotatable state with respect to the crankshaft 7 a. Then, 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) 23a formed on the inner periphery of the left end portion of the interlocking cylinder 23 are engaged with each other The interlocking cylinder 23 rotates integrally with the human power transmitter 28. In this embodiment, the serration portion (or spline portion) 23a formed on the inner periphery of the left end portion of the interlocking cylinder 23 is fitted to the serration portion (or spline portion) 28a of the human power transmission body 28 from the outside There is.

Further, in this embodiment, the rotation detector 11 for detecting the rotation state of the interlocking cylinder 23 is attached to the outer periphery of the left portion of the interlocking cylinder 23. Further, a rotation detector (rotation sensor) 10 as a crankshaft rotation sensor is attached and fixed to the unit case 22 side so as to face the rotation detection body 11 from the outer peripheral side. For example, in the rotation detector 10, an optical sensor having an emitter and a light receiver is arranged in the rotation direction of the rotation detector 11 (not shown). It has a large number of teeth extending rightward in a comb-like shape. Then, when there is a tooth portion of the rotation detection body 11, the incident light and the non-incident state of the light are electrically detected by the light receiving portion of the rotation detector 10 by reflecting and receiving the emitted light. At the same time, the control unit inputs the detected signal to detect the number of rotations (rotation amount) and the rotation direction of the interlocking cylinder 23. In place of the light sensor, a magnetic sensor such as a Hall IC may be provided to detect the number of rotations (the amount of rotation) and the direction of rotation of the interlocking cylinder 23. Here, the interlocking cylindrical body 23 rotates integrally with the human power transmission body 28, and the human power transmission body 28 integrally rotates with the crankshaft 7a, so that the rotation amount and the rotational direction of the interlocking cylindrical body 23 are detected. The rotation number (rotation amount) and the rotation direction of the crankshaft 7a and the pedal 8 can also be detected.

Further, the resultant force transmission body 29 is disposed on the outer periphery of the right side portion of the interlocking cylinder 23 via a one-way clutch (one-way clutch for cutting off the auxiliary driving force) 30. Then, when the pedal 8 is crawled forward, the manual drive force transmitted to the interlocking cylinder 23 is transmitted to the resultant force transmission body 29 via the one-way clutch 30.

The motor 21 has its rotation shaft 21a and rotor 21b rotatably supported by

motor shaft bearings

32,33. Further, a rotary shaft 21a of the motor 21 is protruded rightward, and a motor shaft reduction gear 39 described later is formed on the outer periphery of the protruding portion.

The reduction mechanism 25 has an intermediate shaft 40 disposed parallel to the crankshaft 7 a and a large-diameter reduction gear (first reduction gear: crankshaft-side reduction gear) 36 formed on the left side of the resultant force transmission body 29. And two pairs of reduction gears 36 to 39, etc., which constitute a two-step reduction mechanism. Then, the reduction mechanism 25 combines the manual drive force transmitted through the crankshaft 7a with the auxiliary drive force transmitted from the motor 21, and a resultant force obtained by combining the manual drive force and the auxiliary drive force. Is transmitted to the force transmission body 29.

The intermediate shaft 40 extends leftward and rightward in the longitudinal central portion of the drive unit 20, and is disposed rotatably supported by bearings (intermediate shaft bearings) 34 and 35 in a posture parallel to the crankshaft 7a. . The intermediate shaft 40 is attached with a large diameter second intermediate shaft reduction gear 37, a small diameter third intermediate shaft reduction gear 38, and a one-way clutch 42 for manual drive force cutting.

A one-way clutch 42 for cutting off the manual drive force is disposed between the outer periphery of the intermediate shaft 40 and the inner periphery of the second intermediate shaft reduction gear 37, and cuts the manual drive force from the pedal 8. belongs to. That is, when the motor 21 is not driven by the one-way clutch 42 and the auxiliary driving force is not generated, the manual drive force from the pedal 8 is disconnected by the one-way clutch 42 for manual drive force cutting. Thus, the rotor 21b of the motor 21 need not be rotated. On the other hand, when the motor 21 is driven to rotate, the intermediate shaft 40 and the second intermediate shaft reduction gear 37 are connected via the one-way clutch 42, and the second and third intermediate shaft reduction gears are 37 and 38 integrally rotate with the intermediate shaft 40.

Then, since the small diameter motor shaft reduction gear 39 formed on the rotation shaft 21a of the motor 21 meshes with the large diameter second intermediate shaft reduction gear 37, the motor 21 is rotated to output the auxiliary driving force. In this case, the rotation of the motor 21 is decelerated, and the torque of the auxiliary driving force from the motor 21 is amplified and transmitted to the intermediate shaft 40 side. Further, since the small diameter third intermediate shaft reduction gear 38 meshes with the large diameter first reduction gear 36 integrally formed on the resultant force transmission body 29, the torque of the auxiliary driving force transmitted to the intermediate shaft 40 Is further amplified and transmitted to the first reduction gear 36. Then, in the resultant force transmission body 29 in which the first reduction gear 36 is integrally formed, the manual drive force and the auxiliary drive force from the motor 21 are combined and output from the drive sprocket 13 as a drive force output wheel body Ru. Here, the reduction ratio, which is the ratio of the number of rotations of the motor 21 to the number of rotations of the drive sprocket 13, is set to 30 to 37 (more than 30 and less than 37). Further, the minimum radius of the drive unit 20 around the crankshaft 7a (around the crankshaft) is 50 mm or less.

Further, in this embodiment, only one substrate 24 with a large area is provided as a substrate in the unit case 22 of the drive unit 20. Then, when the base 24 views the drive unit 20 in a side view along the crankshaft 7a (a side view along the axial center direction of the crankshaft 7a), as shown in FIG. (In more detail, it is arrange | positioned so that it may have a part which overlaps with the area | region in which the stator core in the stator of the motor 21 is provided) 21c. Further, in this embodiment, the substrate 24 is disposed so as to overlap in the area of half or more of the stator 21 c of the motor 21. Furthermore, in this embodiment, the substrate 24 is disposed so as to overlap from the area where the stator 21c of the motor 21 is disposed to the area around the crankshaft 7a.

Further, in this embodiment, the substrate 24 is also provided in a region overlapping with the rotor 21 b of the motor 21 as shown in FIG. 3 when viewed from the side. Then, the substrates 24 are arranged so as to overlap in the area of half or more of the rotor 21 b of the motor 21. That is, in this embodiment, the substrate 24 is also provided in a region overlapping the motor 21 (entire motor) as shown in FIG. 3 when viewed from the side, and this substrate 24 is a half of the motor 21. It is arrange | positioned so that it may overlap by the above area.

Further, in this embodiment, the substrate 24 is also provided in a region where the first reduction gear 36 and the stator 21c of the motor 21 do not overlap, as shown in FIG. 3 in a side view. . Further, as shown in FIG. 2, the substrate 24 is provided between the motor 21 and the first reduction gear 36, the resultant force transmission body 29, and the interlocking cylinder 23 in plan view (or front view). There is. Further, when the substrate 24 is viewed from the front (when viewed in the front-rear direction), the substrate 24 is provided in a region overlapping with the human power transmitter 28, as schematically shown in FIG. In this embodiment, the substrate 24 is provided in a region not overlapping with the second reduction gear 37 as shown in FIG. 3 when viewed from the side. The substrate 24 is provided in a region not overlapping with the second reduction gear 37 as schematically shown in FIG. 2 when viewed from the front (when viewed along the front-rear direction). However, the present invention is not limited to this. When the substrate 24 is viewed from the side, the second reduction gear 37 may partially overlap with the second reduction gear 37.

Further, in this embodiment, a rotation detector (rotation sensor) 10 (more specifically, a connection leg for connection of the rotation detector (rotation sensor) 10 as a crankshaft rotation sensor for reading the rotation of the crankshaft on the substrate 24). Section is attached. In this embodiment, as shown in FIG. 2, the bearing 24 supports the rotation detector 11 or the rotation detector (rotation sensor) 10, the crankshaft 7a, etc. The shaft 7a is provided between a bearing 26) and a torque sensor 31 which are supported from the side opposite to the side where the drive sprocket 13 is provided.

Further, in this embodiment, a plurality of magnets are arranged in the circumferential direction so that the magnetic poles of the adjacent magnets are different from each other in the rotor 21b of the motor 21. A substantially cylindrical magnetism imparting member 21d is disposed. The outer peripheral portion of the magnetism imparting member 21d is formed to project to the right, and a motor rotation sensor 43 for reading the rotation of the motor 21 is disposed to face the end 21da of the magnetism imparting member 21d which is projected. ing. The motor rotation sensor 43 is attached to the substrate 24.

In addition, the magnetism imparting member 21 d may be magnetized similarly to the arrangement of the rotor 21 b of the motor 21 only at the end 21 da thereof. Further, in this embodiment, the motor 21 is disposed in an area (deceleration mechanism installation area) in which the demagnetizing member 21 d includes the decelerating mechanism 25 having the plurality of decelerating gears 36 to 39 and the like. It is also used as a partitioning member to partition the motor area (motor installation area). Although grease or the like for reducing friction between the reduction gears 36 to 39 is designed not to intrude into the motor 21 side, the present invention is not limited to this. Reference numeral 21 ca in FIG. 2 denotes a connection wire for energizing the coil of the stator 21 c.

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

Further, according to the above configuration, since the substrate 24 is disposed so as to have a portion overlapping the stator 21 c of the motor 21 when viewed from the side, adopting a substrate with a sufficiently large area as the substrate 24 it can. Further, even when the substrate 24 is disposed also around the crankshaft 7 a as in this embodiment, the area of the region around the crankshaft 7 a in the substrate 24 can be reduced to a small amount. By devising the arrangement (for example, arranging the motor 21 in front of the crank shaft 7a), the distance from the crank shaft 7a to the axle of the rear wheel 4 can be a general bicycle (for example, a so-called sport type bicycle) Can be closer to

Further, as described above, by disposing the substrate 24 so as to overlap with the area of half or more of the stator 21 c of the motor 21 in side view, the area of the region around the crankshaft 7 a in the substrate 24 is minimized. It can be suppressed. Therefore, the distance between the crankshaft 7a and the axle of the rear wheel 4 can be made closer to the function of a general bicycle (for example, a so-called sport-type bicycle). Further, by arranging the substrate 24 so as to have a portion overlapping the stator 21 c of the motor 21 in a side view, the noise generated by the motor 21 can be blocked by the substrate 24. That is, by arranging the substrate 24 to overlap with the area of half or more of the stator 21 c of the motor 21 as described above, the sound insulation effect can be further enhanced.

Further, in the above embodiment, the motor rotation sensor 43 for reading the rotation of the motor 21 and the rotation detector 10 as a crankshaft rotation sensor for reading the rotation of the crankshaft 7a are attached to the substrate 24. With this configuration, the number of parts of the substrate 24 itself in the drive unit 20 can be reduced to only one, and it is possible to reduce the number of parts and the trouble of attaching the substrate. In the present invention, as schematically shown in FIG. 2, the substrate 24 is viewed in plan (or front), and the motor 21, the first reduction gear 36, the resultant force transmission body 29, and the interlocking cylinder 23 are provided. And the rotation detector 10 as the motor rotation sensor 43 or the crankshaft rotation sensor can be easily attached to the substrate 24. Further, as shown in FIG. 2, since the substrate 24 is provided so as to overlap the rotor 21b of the motor 21 and the magnetism imparting member 21d in a side view, the motor rotation sensor 43 can be easily attached to the substrate 24. is there.

However, the present invention is not limited to this, and as shown in FIG. 4, a crankshaft rotation sensor auxiliary substrate 24 A to which the rotation detector 10 as a crankshaft rotation sensor is attached is provided separately from the substrate (main substrate) 24, The crankshaft rotation sensor auxiliary substrate 24A may be connected to the substrate (main substrate) 24 (a first modified example of the first embodiment). Further, as shown in FIG. 5, the motor rotation detection auxiliary substrate 24B to which the motor rotation sensor 43 is attached is provided separately from the substrate (main substrate) 24, and the motor rotation detection auxiliary substrate 24B is a substrate (main substrate) 24. (The second modified example of the first embodiment). In this embodiment, as shown in FIGS. 4 and 5, in plan view, the substrate (main substrate) 24 includes the rotation detector 11 or the rotation detector (rotation sensor) 10, the crankshaft 7a, etc. Between the torque sensor 31 and the bearing 26 (the bearing 26 on the side opposite to the side on which the drive sprocket 13 is provided in the crankshaft 7 a) of the bearing 26. Even in these cases, it is preferable that the substrate (main substrate) 24 be larger (larger in area) than the auxiliary 24A for crankshaft rotation sensor or the auxiliary substrate 24B for detecting motor rotation.

Further, the rotation of the motor 21 is transmitted to the drive sprocket 13 as a driving force output wheel body via the two-stage reduction mechanism 25, and the rotation speed of the motor 21 with respect to the rotation speed of the drive sprocket 13. The reduction gear ratio, which is a ratio, is configured to be 30 to 37. Thereby, a relatively small diameter reduction gear can be used as the first reduction gear 36 coaxial with the crankshaft 7a. As a result, the diameter (radius and diameter) around the crankshaft 7a in the drive unit 20 can be reduced, and the arrangement of the drive unit 21 is devised (for example, the motor 21 is disposed in front of the crankshaft 7a) And so on, the distance from the crankshaft 7a to the axle of the rear wheel 4 can be made closer to a general bicycle (for example, a so-called sport-type bicycle).

Further, by setting the minimum radius of the drive unit 20 around the crankshaft 7a (around the crankshaft) to 50 mm or less, the distance from the crankshaft 7a to the axle of the rear wheel 4 is a general bicycle (for example, It will be possible to get closer to a sport-type bicycle. Then, by setting the minimum radius of the drive unit 20 around the crankshaft 7a (around the crankshaft) to 45 mm or less, the distance from the crankshaft 7a to the axle of the rear wheel 4 can be further reduced to a general bicycle (for example, It will be possible to get closer to a sport-type bicycle.

Second Embodiment
Although the case where the reduction gear ratio of the reduction mechanism 25 is constant was described in the above embodiment, the invention is not limited thereto, and a plurality of reduction gear ratios (two gear stages in this embodiment) are selected and switched. A reduction mechanism 25A having a possible shifting function may be provided in the drive unit 20.

As shown in FIGS. 6 to 10, the reduction mechanism 25A provided in the drive unit 20 according to this embodiment is a one-way clutch (for cutting off the auxiliary driving force) on the outer peripheral side and the right side of the interlocking cylinder 23. A plurality of selectable shift speeds with different gear ratios (in this embodiment, two shift speeds of a low speed stage and a high speed stage) via a one-way clutch 30 to combine the driving force with the force transmitting member 29. To communicate.

The speed reduction mechanism 25A is rotatably disposed on the outer periphery of the crankshaft 7a, and the rotation transmission cylinder 49 transmits the rotation of the interlocking cylinder 23 via the one-way clutch (one-way clutch for cutting off the auxiliary driving force) 30. A low speed transmission gear (also referred to as a crankshaft-side low speed transmission) 36A integrally formed extending radially outward from the right cylindrical portion of the rotation transmission cylinder 49, the rotation transmission cylinder 49, and the resultant force transmitting member 29 and a low speed stage clutch 51 capable of transmitting the driving force of the crankshaft low speed transmission gear 36A to the resultant force transmission body 29 and a high speed stage rotatably disposed on the outer periphery of the resultant force transmission body 29. Low-speed transmission gear (also referred to as intermediate-shaft low-speed transmission gear) formed integrally with the transmission gear (also referred to as crankshaft high-speed transmission gear) 36B and the intermediate shaft 40 and meshed with the crankshaft-side low-speed transmission gear 36A An intermediate shaft tooth portion 40a integrally formed with the intermediate shaft 40 and engaged with a tooth portion (or serration portion or spline portion) 55b formed on the inner peripheral side of the high speed gear clutch 55 described later; And a high-speed stage clutch 55 capable of transmitting the resultant force from the intermediate shaft 40 to the crankshaft-side high-speed transmission gear 36B and the resultant force transmitting body 29 and provided on the outer periphery of the intermediate shaft tooth portion 40a A high speed gear shift tooth portion (intermediate speed gear tooth portion (intermediate gear) which is constituted by an engagement claw which can freely move out of the gear clutch 55 (more specifically, the main body 55a of the high speed gear clutch 55) to the outer circumferential side The shaft-side high-speed gear shift teeth, so-called engagement claws of a so-called high-speed clutch 55 (see FIGS. 9 and 10) and the right side of the intermediate shaft high-speed gear teeth 38B A gear shift body 61 which is freely moved according to the selected gear, an arm 62 for shifting movement which engages with the gear shift body 61 to move the gear shift body 61 in the crankshaft direction, etc. Is equipped.

Then, when the pedal 8 is crawled to move forward, the manual drive force transmitted to the interlocking cylinder 23 is transmitted to the rotation transmission cylinder 49. In this embodiment, the high speed gear clutch 55 is disposed on the outer peripheral side of the intermediate shaft 40 so as to be movable in the same axial direction as the axial center of the intermediate shaft 40.

Here, the crankshaft-side low-speed transmission gear 36A has a larger diameter than the crankshaft-side high-speed transmission gear 36B, and the intermediate-shaft low-speed transmission gear 38A has a diameter larger than that of the intermediate shaft-side high-speed transmission gear 38B. It has a small diameter. Thus, the rotational force of the intermediate shaft 40 is transmitted to the crankshaft side low speed transmission gear 36B and the rotation transmission cylinder 49 at low speed rotation, and is transmitted to the crankshaft high speed transmission gear 36B at high speed.

The gear shift movement arm 62 is preferably driven by an electric transmission 51 (shown schematically in FIG. 7) provided inside the drive unit 20 (or outside the drive unit), for example, It is preferable that the hand operation unit 18 be provided with a switch for gear shift switching so that the gear can be switched. However, the present invention is not limited to this, and an arm for shift movement (a shift portion moved through a wire or the like) 62 may be provided in the vicinity of the steering wheel.

When the low gear is selected, as shown in FIGS. 6 and 8, the gear shift member 61 is moved to the left side by the gear shift movement arm 62, and the high speed clutch 55 can be engaged and disengaged. The intermediate shaft side high speed gear shift tooth portion 38B formed of the joint claw is turned down and separated from the crankshaft high speed gear shift gear 36B. Therefore, the manual drive force transmitted from the interlocking cylinder 23 through the one-way clutch (one-way clutch for cutting off the auxiliary drive force) 30 and the intermediate shaft 40 and the intermediate shaft side low-speed transmission gear 38A from the motor side The auxiliary driving force transmitted through is transmitted to the rotation transmission cylinder 49 in a relatively low rotation state and combined, and this rotation driving force (combined force) is transmitted through the low speed stage clutch 51 and the combined force transferring body 29 to the drive sprocket It is output from 13.

When the high gear is selected, the gear shift member 61 is moved to the right side by the gear shift movement arm 62 as shown in FIGS. The claw portion engageable with the step-change gear 36B (specifically, the tooth portion of the crankshaft-side high-speed step-change gear 36B) can be erected, and the rotation of the crankshaft-side high-speed step-change gear 36B can be transmitted to the resultant force transmission body 29 State. Therefore, the manual driving force transmitted from the interlocking cylinder 23 through the one-way clutch (one-way clutch for cutting off the auxiliary driving force) 30 is the crankshaft-side low speed transmission gear 36A and the intermediate shaft low speed transmission While being transmitted to the intermediate shaft 40 via 38A, the auxiliary driving forces are combined to form a resultant force. Then, the resultant force is transmitted to the resultant force transmission body 29 via the high speed gear clutch 55 in a relatively high-speed rotation state via the intermediate shaft high speed gear shift gear 38B and the crankshaft high speed gear shift gear 36B to drive the sprocket It is output from 13. At this time, since the resultant force transmission body 29 rotates at a higher speed than the rotation transmission cylinder 49, the low speed clutch 51 is rotated.

Thus, by using this drive unit 20, it is also possible to switch the shift position in the drive unit 20. Also in this embodiment, the same effect can be obtained by providing the substrate 24 and the like in the same arrangement as the above embodiment. In addition, the reduction gear ratio, which is the ratio of the number of rotations of the motor 21 to the number of rotations of the drive sprocket 13 in the low gear, is 30 to 37, and the reduction gear ratio in the high gear is less than this. A crankshaft having a relatively small diameter can be used as the crankshaft side low speed transmission gear 36A (and the crankshaft high speed transmission gear 36B) coaxial with 7a, and similar effects can be obtained.

In the above embodiment, the high speed gear clutch 55 is provided on the outer periphery of the intermediate shaft 40. However, the present invention is not limited to this, and may be provided in the outer peripheral region of the crankshaft 7a. Further, as in the above embodiment, an auxiliary substrate for crankshaft rotation sensor 24A to which the rotation detector 10 as a crankshaft rotation sensor is attached is provided separately from the substrate (main substrate) 24, and for this crankshaft rotation sensor The auxiliary 24A may be configured to be connected to the substrate (main substrate) 24. Further, the motor rotation detection auxiliary substrate 24B to which the motor rotation sensor 43 is attached is provided separately from the substrate (main substrate) 24, and the motor rotation detection auxiliary substrate 24B is connected to the substrate (main substrate) 24. May be

In the above embodiment (the first and second embodiments), the motor shaft (rotation shaft 21a of motor 21) is disposed forward of crankshaft 7a, and a straight line connecting crankshaft 7a and motor shaft 21a. The intermediate shaft 40 is disposed below. The second and third intermediate shaft reduction gears 37 and 38 attached to the intermediate shaft 40, the motor shaft reduction gear 39 attached to the motor shaft 21a, and the outer periphery of the crankshaft 7a As shown in FIG. 11, the first reduction gear (crankshaft side reduction gear) 36 is made into a helical (diagonal tooth) gear to achieve noise reduction. FIG. 11 corresponds to the first embodiment. In addition, when the motor 21 is driven and the auxiliary driving force is output, the motor shaft 21a and the motor shaft reduction gear 39 are rotated clockwise (clockwise) in a right side view. The second intermediate shaft reduction gear 37 and the intermediate shaft 40 and the third intermediate shaft reduction gear 38 meshing with each other are rotated counterclockwise (counterclockwise) in a right side view, and the third intermediate shaft reduction gear The first crankshaft-side reduction gear 36 meshing with 38 is rotated clockwise (clockwise) in a right side view.

In such a configuration, as shown in FIG. 12, when the reduction gears 36 to 39 of the reduction mechanism 25 mesh with each other, force vectors (reaction forces) V1 to P6 are generated, and as shown in FIG. Act on. 12 shows a force vector (reaction force) acting on the contact portion of the gear (a force vector (reaction force) ultimately related to the intermediate shaft 40), and FIG. 13 shows a force vector (reaction force) on the intermediate shaft 40 ) Indicates that the force vector is collected at the axial center of the intermediate shaft 40).

12 and 13, V1 is a tangential force vector to the intermediate shaft bearing 35 due to the engagement of the motor shaft reduction gear 39 and the second intermediate shaft reduction gear 37, and V2 is the motor shaft reduction gear 39 and the second intermediate shaft The separation force vector to the intermediate shaft bearing 35 by meshing with the reduction gear 37, V3 is a load vector by the thrust force to the intermediate shaft bearing 35 by meshing between the motor shaft reduction gear 39 and the second intermediate shaft reduction gear 37 . Further, V4 is a tangential force vector to the intermediate shaft bearing 35 due to the engagement between the first reduction gear (crankshaft side reduction gear) 36 and the third intermediate shaft reduction gear 38, and V5 is a first reduction gear (crankshaft (Side reduction gear) 36 and the separation force vector to the intermediate shaft bearing 35 by meshing between the third intermediate shaft reduction gear 38, V6 is the first reduction gear (crankshaft side reduction gear) 36 and the third intermediate shaft reduction A load vector due to the thrust force on the intermediate shaft bearing 35 due to the meshing with the gear 38, V7 is a reaction force (combined force) vector acting (combined) on the intermediate shaft 40.

According to the arrangement configuration, the force vectors V1 to P6 to the intermediate shaft 40 generated when the reduction gears 36 to 39 are engaged with each other are less likely to cancel each other, so the state in which these force vectors V1 to P6 are combined In the intermediate shaft 40, a relatively large force vector V7 acts. Therefore, the

intermediate shaft bearings

34, 35 rotatably supporting the intermediate shaft 40, particularly, the right intermediate shaft bearing close to the third intermediate shaft reduction gear 38 meshing with the first crankshaft side reduction gear 36 transmitting the resultant force In order to receive a large reaction force 35, a large one capable of supporting a large force is used. As a result, the drive unit 20 is enlarged (in the present embodiment, in particular, the intermediate shaft 40 of the drive unit 20 is The dimension in the width direction of the place where it is arranged becomes large).

Thus, when the drive unit 20 is enlarged and the widthwise dimension of the drive unit 20 is increased, the distance L1 (see FIG. 2) between the left and right crank arms 7b is a common bicycle (for example, a so-called sport type bicycle) Because it increases more than the above, there is a drawback that the function as a general bicycle (for example, a so-called sport-type bicycle) is difficult to access.

In order to cope with such a problem, in the drive unit 20 of the electrically assisted bicycle according to the third embodiment of the present invention shown in FIGS. 14 to 16, the rotating shaft 21a of the motor 21, the intermediate shaft 40, The crankshaft 7a is disposed (this arrangement is the same as the above embodiment), but unlike the above embodiment, the intermediate shaft 40 is disposed above the straight line connecting the crankshaft 7a and the motor shaft 21a. It is done. Further, in this case, with the drive unit 20 viewed from the right side as viewed from the right side with respect to the advancing direction, as shown in FIG. 15, with respect to a line A connecting the axis of the crankshaft 7a and the axis of the motor shaft 21a. Of the line connecting the axis of the crankshaft 7a and the axis of the intermediate shaft 40 is within 30 to 70 degrees in the clockwise direction. An axis 40 is arranged.

The drive unit 20 of the electrically assisted bicycle according to the third embodiment mainly includes the intermediate shaft 40, the crankshaft 7a, and the motor shaft, as compared with the drive unit 20 according to the first embodiment. The arrangement (21a) and the structure (size etc.) of the bearing associated with this arrangement are different, and the other configuration is the same as that of the drive unit 20 according to the first embodiment. That is, the second and third intermediate shaft reduction gears 37 and 38 attached to the intermediate shaft 40, the motor shaft reduction gear 39 attached to the motor shaft 21a, and the outer periphery of the crankshaft 7a As shown in FIG. 11, the first reduction gears (crankshaft side reduction gears) 36 are all helical (diagonal teeth) gears to achieve noise reduction. In addition, when the motor 21 is driven and the auxiliary driving force is output, the motor shaft 21a and the motor shaft reduction gear 39 are rotated clockwise (clockwise) in a right side view. The second intermediate shaft reduction gear 37 and the intermediate shaft 40 and the third intermediate shaft reduction gear 38 meshing with each other are rotated counterclockwise (counterclockwise) in a right side view, and the third intermediate shaft reduction gear The first crankshaft-side reduction gear 36 meshing with 38 is rotated clockwise (clockwise) in a right side view.

In such a configuration, as shown in FIG. 15, when the reduction gears 36 to 39 of the reduction mechanism 25 mesh with each other, force vectors (reaction forces) V11 to P16 are generated, and as shown in FIG. Act on. 15 shows a force vector (reaction force) acting on the contact portion of the gear (a force vector (reaction force) ultimately related to the intermediate shaft 40), and FIG. 16 shows a force vector (reaction force) on the intermediate shaft 40 ) Indicates that the force vector is collected at the axial center of the intermediate shaft 40).

In FIG. 15 and FIG. 16, V11 is a tangential force vector to the intermediate shaft bearing 35 by the engagement of the motor shaft reduction gear 39 and the second intermediate shaft reduction gear 37, and V12 is the motor shaft reduction gear 39 and the second intermediate shaft The separation force vector to the intermediate shaft bearing 35 by meshing with the reduction gear 37, V13 is a load vector by the thrust force to the intermediate shaft bearing 35 by meshing between the motor shaft reduction gear 39 and the second intermediate shaft reduction gear 37 . Further, V14 is a tangential force vector to the intermediate shaft bearing 35 due to the engagement between the first reduction gear (crankshaft side reduction gear) 36 and the third intermediate shaft reduction gear 38, and V15 is a first reduction gear (crankshaft (Side reduction gear) 36 and the separation force vector to the intermediate shaft bearing 35 by the meshing of the third intermediate shaft reduction gear 38, V16 is the first reduction gear (crankshaft side reduction gear) 36 and the third intermediate shaft reduction A load vector due to a thrust force on the intermediate shaft bearing 35 due to meshing with the gear 38, P17 is a reaction force (combined force) vector acting on the intermediate shaft 40 (combined force).

According to the above-mentioned arrangement, V11 to P16 to the intermediate shaft 40 generated when the reduction gears 36 to 39 mesh with each other cancel each other, and finally, the reaction force (synthetic force) P17 acting on the intermediate shaft is As the intermediate shaft bearing 35 can be smaller, it is possible to adopt a small size (small in the width direction or radial direction) capable of supporting a relatively small load, which in turn reduces the size of the drive unit 20 (for example, The drive unit 20 can be miniaturized in the width direction or the like. As a result, the distance L2 between the crank arms can be made close to the distance between the crank arms of a general bicycle (for example, a so-called sport type bicycle).

Further, in this embodiment, although the drive sprocket 13 having a shape in which the center side is expanded to the right side is used, by using a small size as the intermediate shaft bearing 35, an intermediate portion of the drive sprocket 13 is formed. It can arrange so that the part holding the intermediate shaft bearing 35 in the shaft bearing 35 or the 1st case 22a can be entered, and the drive unit 20 is further miniaturized (for example, the drive unit 20 is miniaturized in the width direction etc.) can do. As a result, the distance L2 between the crank arms can be made closer to a general bicycle (for example, a so-called sport bicycle).

In the drive unit 20 of the electrically assisted bicycle according to the third embodiment, when the motor shaft (rotation shaft of the motor 21) 21a is disposed forward of the crankshaft 7a, the intermediate shaft 40 is a crank Although the case where it arrange | positions below the straight line which ties the axis | shaft 7a and the motor shaft 21a was described, it does not restrict to this. That is, as shown in FIG. 17, when the motor shaft 21a is disposed rearward of the crankshaft 7a, the intermediate shaft 40 is disposed above the straight line connecting the crankshaft 7a and the motor shaft 21a. It should be configured.

Also, in any case, such as when the intermediate shaft 40 is disposed on the right or left side of the straight line connecting the crankshaft 7a and the motor shaft 21a, the drive unit 20 is viewed from the right side in a traveling direction In the state, the crossing angle of the line connecting the axial center of the crankshaft 7a and the axial center of the intermediate shaft 40 is clockwise with respect to the line connecting the axial center of the crankshaft 7a and the axial center of the motor shaft 21a. It is preferable to arrange the crankshaft 7a, the motor shaft 21a and the intermediate shaft 40 so as to be within 30 degrees to 70 degrees.

Further, as in the drive unit 20 of the electrically assisted bicycle according to the second embodiment, the same operation and effect can be obtained by applying the same arrangement and configuration to the drive unit 20 having a built-in transmission mechanism. It is.

The present invention is applicable to drive units for various types of electrically assisted bicycles capable of traveling by adding an auxiliary driving force generated by a motor to a manual driving force by a pedaling force from a pedal and such electrically assisted bicycles.

Claims

A driving unit of an electrically assisted bicycle provided with the motor and attached to an electrically assisted bicycle capable of traveling by applying an assisting driving force by a motor to a manual driving force by a pedaling force from a pedal,
A mounting portion attached to an intermediate position between a front wheel and a rear wheel in the electrically powered bicycle, a crankshaft insertion region through which a crankshaft to which a manual drive force from the pedal is transmitted is inserted, and a drive for outputting a drive force Has a force output wheel body,
The crankshaft and the motor are disposed at mutually different axial centers;
A drive of an electrically assisted bicycle characterized in that a substrate is disposed inside the drive unit, and the substrate has a portion overlapping the stator of the motor when viewed from the side along the crankshaft. unit.
The drive unit of the electrically assisted bicycle according to claim 1, wherein the substrate is arranged to overlap in a half or more area of a stator of the motor in a side view.
The drive of the electrically assisted bicycle according to claim 1 or 2, wherein the substrate is disposed so as to overlap from the area where the motor stator is disposed to the area around the crankshaft in a side view. unit.
The drive unit of the electrically assisted bicycle according to any one of claims 1 to 3, wherein a motor rotation sensor for reading the rotation of the motor is attached to the substrate.
The drive unit of the electrically assisted bicycle according to any one of claims 1 to 4, wherein a crankshaft rotation sensor for reading the rotation of a crankshaft is attached to the substrate.
The motor-assisted vehicle according to any one of claims 1 to 3, wherein a motor rotation sensor for reading the rotation of the motor and a crankshaft rotation sensor for reading the rotation of the crankshaft are attached to the substrate. Bicycle drive unit.
The substrate according to any one of claims 1 to 6, wherein a plurality of substrates are provided, and the substrate having a portion overlapping a stator of a motor is the substrate of the largest area of the plurality of substrates. The drive unit of the electric assist bicycle.
The rotation of the motor is configured to be transmitted to a drive output wheel that outputs a drive via a two-step reduction mechanism,
8. The drive unit of the electrically assisted bicycle according to any one of claims 1 to 7, wherein a reduction ratio, which is a ratio of the number of rotations of the motor to the number of rotations of the driving force output wheel, is 30 to 37.
The drive unit of the electrically assisted bicycle according to any one of claims 1 to 8, wherein the minimum radius around the crankshaft is 50 mm or less.
A reduction mechanism having multiple pairs of reduction gears is provided;
The reduction gear mechanism is rotatably disposed on an outer periphery of the crankshaft, an intermediate shaft disposed parallel to the crankshaft, a plurality of intermediate shaft reduction gears provided on the intermediate shaft, and driven by manual power. A crankshaft side reduction gear to which force and auxiliary driving force are transmitted, and a motor shaft reduction gear provided on the motor shaft,
An intermediate shaft bearing rotatably supporting the intermediate shaft;
The intermediate shaft is disposed between the crankshaft and the motor shaft in the front-rear direction, and connects the crankshaft and the motor shaft when the motor shaft is disposed forward of the crankshaft. When the motor shaft is disposed below the straight line and the motor shaft is disposed rearward of the crankshaft, the intermediate shaft is disposed above the straight line connecting the crankshaft and the motor shaft. An electrically assisted bicycle comprising the drive unit according to any one of claims 1 to 9.
Connecting the shaft center of the crank shaft and the shaft center of the intermediate shaft to the line connecting the shaft center of the crank shaft and the shaft center of the motor shaft while looking in the direction of travel of the electric assist bicycle and viewing from the right side The electric assist provided with a drive unit according to claim 10, wherein the crankshaft, the motor shaft and the intermediate shaft are arranged such that the crossing angle of the lines is within 30 to 70 degrees in the clockwise direction. bicycle.
A drive power supply device comprising: a drive unit for the electrically assisted bicycle according to any one of claims 1 to 9; and a storage battery for supplying power to the drive unit.
An electrically assisted bicycle comprising the drive unit of the electrically assisted bicycle according to any one of claims 1 to 9, or the drive power feeding device according to claim 12.