JPH10305794A - Motor-assisted bicycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a motor-assisted bicycle compact and light in weight by adopting a flat motor as a driving source, directly assembling this motor on a crankshaft and further assembling also a reduction gear of a single stage oscillating inscribed engagement type planetary gear structure on the crankshaft by combining the motor and the reduction gear. SOLUTION: A flat motor 30 which is one of main elements of a motor driving system MD is assembled on a crankshaft 12 coaxially with the crankshaft 12. The flat motor 30 is connected with an eccentric body 51 used as also an input shaft of a reduction gear 50 via a one-way clutch 40. This reduction gear 50 has an oscillating inscribed engagement type planetary gear structure. The eccentric body 51 is assembled on the outer periphery of a torque ring 91 via a bearing 51b by decentering the shaft center 02 of the body 51 itself for the shaft center 01 of the crankshaft 12 by e. Thus, both of the motor 30 and the reduction gear 50 can be stored in a range of the size of a sprocket 62 on the crankshaft 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric bicycle using a motor as an auxiliary power source.

[0002]

2. Description of the Related Art Conventionally, a sprocket which has a human drive system and a motor drive system and is incorporated coaxially with a crankshaft and connected to a rear wheel is rotated by a motor as well as a pedal force of a human. Has been proposed.

For example, in Japanese Patent Application Laid-Open No. 57-74285, a motor is disposed behind a crankshaft so that its axis is parallel to the crankshaft, and between the crankshaft and the output shaft of the motor. An electric bicycle having an output shaft for transmitting the rotation of the vehicle to the rear wheels has been proposed.

Japanese Patent Application Laid-Open No. 8-53094 discloses that the rotation of a motor arranged perpendicular to a crankshaft is first reduced by a first stage planetary roller speed reducer, and then a second stage bevel gear speed reducer is provided. There has been proposed an electric bicycle in which the speed is reduced and the rotation direction is changed to a direction coaxial with the crankshaft.

Further, Japanese Patent Application Laid-Open No. 5-262273 proposes a motor in which the motor is arranged near the rear wheel axle (instead of being arranged near the crankshaft). This electric bicycle uses two flat motors for rotation.
The transmission is transmitted to the rear wheel axle via a stepped belt type reduction mechanism and a one-stage gear type reduction mechanism (total three-stage reduction mechanism). The flat motor is mounted on a shaft arranged parallel to the rear wheel axle, and the three-stage reduction mechanism is also mounted on a shaft arranged parallel to the rear wheel axle.

[0006]

Electric bicycles are originally intended to allow a cyclist to pedal more comfortably (without compromising safety).
The lighter the drive mechanism, the better it is, and the smaller the drive mechanism, the better.

Further, since the battery runs on a battery, it is necessary to have a light weight and high transmission efficiency in order to extend the running distance. In this regard, in the electric bicycle disclosed in Japanese Patent Application Laid-Open No. 57-74285, the crankshaft, the output shaft, and the motor are arranged in this order in the front-rear direction of the vehicle body.
There is a problem that the driving device is increased in size, and there is a problem that when a motor having a large output is used as the motor, the motor protrudes largely to the side of the vehicle body (lateral direction).

On the other hand, in the electric bicycle proposed in the above-mentioned Japanese Patent Application Laid-Open No. 5-53094, since the motor is arranged orthogonal to the crankshaft, even if a motor having a large output is incorporated, the motor projects to the side of the vehicle body. Although the problem does not arise, most of the motor drive system is arranged in a direction perpendicular to the crankshaft (specifically, because it protrudes greatly in front of the crankshaft), the existence of a drive device is present. There was a problem that was very noticeable.

The electric bicycle proposed in Japanese Patent Application Laid-Open No. 5-262273 uses a flat type motor, so that a motor having a relatively large output is mounted on a shaft parallel to the rear wheel axle. Although the problem that the motor protrudes in the left-right direction of the vehicle body can be avoided, a very large drive in the radial direction is achieved because the three-stage speed reduction mechanism is incorporated on the shaft arranged around the rear wheel axle. There is a problem that the device space is required. Further, since the motor drive system is built around the rear wheel axle, a mechanism for detecting the torque of the crankshaft cannot be incorporated in the drive device due to the configuration, and a drive assist according to the treading force is performed. There was a problem that it was difficult to take. In fact, in the electric bicycle disclosed in Japanese Patent Application Laid-Open No. 5-262273, a driving force is provided to a rear wheel by a motor drive system regardless of a pedaling force of a person, and in that sense,
Driving assistance basically did not correspond to human intention to step on the pedal, and was more similar to the concept of a motorcycle than a bicycle.

Furthermore, not only the above three examples, but also electric bicycles according to various configurations that have been proposed in the past are all two.
Since the rotation of the motor is adjusted to the rotation of the crankshaft (or the rear wheel axle) by a three-stage or three-stage reduction mechanism, the power loss in the reduction mechanism is not small, and when the vehicle is traveling with driving assistance, There is a problem that the battery consumption is large and running resistance is high when running without driving assistance.

The present invention has been made in view of such a conventional problem, and has drastically reviewed the drive structure of an electric bicycle that has been conventionally proposed, and is lighter, more compact, and has an outer appearance. There is not much difference from a normal man-powered bicycle, and by arranging the motor drive system around the crankshaft, it is possible to incorporate a mechanism for detecting the torque of the crankshaft, and to assist the drive according to the pedaling force of the person. It is an object of the present invention to provide an electric bicycle whose configuration can be easily realized.

[0012]

SUMMARY OF THE INVENTION The present invention has a manual drive system and a motor drive system, and a sprocket which is incorporated coaxially with a crankshaft and is connected to a rear wheel is capable of controlling a motor in addition to a stepping force on a pedal by a person. An electric bicycle configured to be rotated by the motor, wherein the motor drive system has a flat motor having an output shaft coaxial with the crankshaft;
A speed reducer for reducing the rotation of the flat motor and transmitting the reduced speed to the sprocket, wherein the speed reducer is incorporated with an eccentric body rotated by the flat motor and swingably rotatable with respect to the crankshaft via the eccentric body. An external gear, an internal gear in which the external gear inscribes while swinging, and a mechanism for extracting only the rotation component of the external gear are connected to the external gear and to the sprocket. And a reduction gear having a one-stage swinging internally meshing planetary gear structure mainly composed of a transmission ring, and the reduction gear and the flat motor are both coaxial with the crankshaft on the crankshaft. In addition, the above problem is solved by being arranged between the pedals.

In the present invention, the drive system of the motor is not cranked (rather than around the rear wheel axle) in order to realize driving assistance in accordance with the pedal depression force so that there is as little uncomfortable feeling as possible with a normal human-powered bicycle. Built around the shaft.

In order to prevent the drive unit from protruding greatly from the crankshaft in the longitudinal direction of the vehicle body, a flat type motor (flat type DC motor) is first used as the motor, It was decided to incorporate it directly on the crankshaft (rather than on an axis parallel to the axis) and coaxially with the crankshaft.

Since the output of a flat type motor greatly depends on the size in the radial direction, even if the output is increased, the axial length occupying the crankshaft is one of the normal pedal interval.
Only about に し to ４. Also, with regard to the size in the radial direction, a sufficient output can be ensured within the range of the size of the sprocket (large gear fixed to the crankshaft) of a normal human powered bicycle.

According to the present invention, as a speed reduction mechanism to be combined with a flat type motor directly incorporated on the crankshaft, as a result of intensive investigation, it has been known that the speed reduction mechanism of this type of electric bicycle has not received any attention at all. A reduction mechanism with a meshing planetary gear structure has been adopted.

In this speed reduction mechanism, an eccentric flange portion called an eccentric body is formed on the input shaft so as to protrude in the radial direction, and an external gear is mounted on the outer periphery of the flange portion so as to be swingably rotatable with respect to the input shaft. An internal gear in which the external gear inscribes while swinging is provided on the outer periphery of the external gear, and only the rotation component of the external gear is taken out as an output.

This oscillating internal meshing type planetary gear structure reduction mechanism has been used in other fields such as, for example, a drive mechanism for a joint of an industrial precision robot. Or there was no example used in the field of electric bicycles.

The present inventors have paid attention to the fact that this reduction mechanism has a characteristic that a large reduction ratio of 1 / (several tens) can be obtained with only one stage. That is, since it is a one-stage type, the transmission efficiency is higher than that of a structure in which two stages and three stages are repeatedly decelerated, and the axial length is naturally sufficient for one stage. Therefore, if this speed reduction mechanism is used, both the motor and the speed reducer can be incorporated in the space between both pedals of the crankshaft, in combination with the adoption of a flat type motor.

As a result, as described above (even in the radial direction), the electric bicycle can be accommodated within the size of the sprocket of the conventional rickshaw, thereby providing an electric bicycle which has almost no uncomfortable feeling as compared with the conventional rickshaw. Will be able to

Further, since both the motor and the speed reducer are incorporated "coaxially" with the crankshaft, the assembling is easy, and in particular, the one-way clutch can be easily assembled at any place (the one-way clutch). This makes it easy to change the design relating to the incorporation of).

Furthermore, since the motor drive system is built around the crankshaft (not around the rear wheel axle),
Various methods for detecting the torque of the crankshaft can be easily incorporated, and a drive control mechanism for the motor according to the pedaling force of a person can be easily realized.

[0023]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a front view schematically showing an electric bicycle to which a driving device according to the present invention is applied.

The crankshaft 12 is conventionally disposed near the intersection of the seat tube 14 and the down tube 16. As shown in FIG. 1, the overall appearance of this electric bicycle is
Since the driving device 10 is housed around the crankshaft 12, there is almost no difference from the conventional manual bicycle. That is, the seat tube 14, the down tube 16,
The frame configuration around the crankshaft such as the chain stay 18 and the seat stay 20, and the configurations of the pedal 22 and the crank 24 are all basically the same as the conventional one.

A battery 32 for driving the flat motor 30 of the driving device 10 is mounted along the rear side of the seat tube 14 in this embodiment. However, the battery 32 may be mounted, for example, along with the down tube 16.

FIG. 2 is a sectional view of a main part of the drive device 10 taken along the line II-II in FIG.

A motor drive system MD and a manual drive system PD are incorporated in the crankshaft 12 coaxially with the crankshaft 12, and are covered and protected by a casing 26.

The torque of the crankshaft 12 (the depression force of a human pedal) is detected by a torque detection mechanism TS.

First, the motor drive system MD will be described.

The motor drive system MD is mainly composed of a flat motor 30 driven by a battery 32, a one-way clutch 40, and a speed reducer 50 having a planetary gear structure of an oscillating internal meshing type. Sprocket 6
2 is driving.

The details will be described below in order.

The flat motor 30, which is one of the main elements of the motor drive system MD, belongs to a so-called flat DC motor, and is incorporated on the crankshaft 12 coaxially with the crankshaft 12. The flat motor 30 includes an armature coil 31, a field permanent magnet 32, a case 33 also serving as a yoke, a brush 34, and a commutator (commutator) 35.
It is mainly composed of The flat motor 30 is known per se, and a current controlled by the commutator 35 flows through the armature coil 31 in the magnetic field formed by the field permanent magnet 32, and the electromagnetic force generated by the current is The armature coil 31 rotates.

In FIG. 2, reference numeral 36 denotes a brush spring, 37 denotes a brush holder, and 38a and 38b denote bearings.

The hub 31 a of the armature coil 31 corresponding to the output shaft of the flat motor 30 is connected to the one-way clutch 40.

The one-way clutch 40 is interposed between the flat motor 30 (the armature coil 31) and the input side (the spline 41) of the speed reducer 50, and
Engagement is enabled only when the forward rotation on the 0 side (reverse rotation when viewed from the transmission ring 60) is relatively faster than the forward rotation (same) on the reduction gear 50 side. One-way clutch 4
The connecting spline 41, which is the output side of 0, is connected to the eccentric body 51 also serving as the input shaft of the speed reducer 50 via a spline 51a.

The speed reducer 50 is of a planetary gear structure of a rocking internal meshing type, and is incorporated so as to be rotatable with respect to the crankshaft 12 via the eccentric body 51 and the eccentric body 51. An external gear 52, an internal gear 53 with which the external gear 52 inscribes while swinging, and an external gear via a mechanism (internal pin hole 54 and internal pin 55) for extracting only the rotation component of the external gear 52. 52 and a transmission ring 60 connected thereto.

As shown in FIG. 3, the eccentric body 51 has its own shaft center 02 with respect to the shaft center 01 of the crankshaft 12 via the bearing 51b (at the outer periphery of a torque ring 91 described later). The spline 41 is eccentrically mounted, and rotates eccentrically around the crankshaft 12 only once each time the connecting spline 41 makes one rotation.

The external gear 52 is rotatably mounted on the outer periphery of the eccentric body 51 via a bearing 52a. Therefore, the external gear 52 is also incorporated with its axis (coincident with 02) shifted from the axis 01 of the crankshaft 12 by e. The external gear 52 has trochoidal external teeth 52b, and meshes internally with the internal gear 53 while swinging. The number of external teeth 52b is set to 43 in the illustrated example.

The internal gear 53 is incorporated in the casing 26 concentrically with the crankshaft 12. This internal gear 5
The inner teeth 3 are specifically formed by outer pins 53b rotatably engaged with the outer pin holes 53a. The number of the outer pins 53b (corresponding to the number of the internal teeth of the internal gear 53)
In the illustrated example, the number is set to 44, which is one more than the number of the external teeth 52b of the external gear 52.

The mechanism for extracting only the rotation component of the external gear 52 includes an inner pin hole 54 and an inner pin 55.
The inner pin 55 is supported (projected in a cantilevered manner) by the transmission ring 60, and the inner pin hole 5
4 is loosely fitted. The swing component of the external gear 52 is absorbed by the gap between the inner pin hole 54 and the inner pin 55, and only the rotation component is transmitted to the transmission ring 60 via the inner pin 55. Reference numeral 55a in the figure denotes an inner roller that covers the outer periphery of the inner pin 55, and reduces the sliding resistance between the inner pin 55 and the inner pin hole 54.

The transmission ring 60 includes a sprocket 62
Is linked to The transmission ring 60 is an output member of the motor drive system MD and also serves as an output member of the manual drive system PD.

Next, the manual drive system will be described.

Returning to FIG. 2, the human-powered drive system PD mainly includes the crankshaft 12, which is rotated via the crank 24 by the pedaling force of a human, a one-way clutch 70, and a gearbox 80. The human pedaling force is transmitted through these members to the transmission ring 6 which is a common member with the motor drive system MD.
0 to the sprocket 62.

The one-way clutch 70 is interposed between the crankshaft 12 and the input side (carrier 82) of the gearbox 80, and when the forward rotation of the crankshaft 12 is faster than the forward rotation of the gearbox 80. And the power can be transmitted. When the driver rotates the crankshaft 12 in the reverse direction, the (reverse) rotation on the crankshaft 12 side is "relatively" slower than the (normal) rotation on the gearbox 80 side, so that the idle rotation occurs. Therefore, power is not transmitted to the other side from either the crankshaft 12 side or the gearbox 80 side.

The gearbox 80 has a so-called simple planetary gear structure, and includes a sun gear 81 provided on the outer periphery of the crankshaft 12 (more specifically, integrated with a torque ring 91 described later), A carrier 82 that rotates with the rotation of the crankshaft 12, a planetary gear 83 supported by the carrier 82 and revolves around the outer periphery of the sun gear 81, the planetary gear 83 is inscribed, and the transmission ring 6
0 and a ring gear 84 integrated therewith.

The sun gear 81 includes a torque detecting mechanism TS
(Described later). The carrier 82 is connected to the crankshaft 12 via a one-way clutch 70 and rotates at the same speed as the crankshaft 12 (the input member of the speed increaser 80). The planetary gear 83 is rotatably supported by the carrier 82 and is revolvably incorporated around the outer periphery of the sun gear 81 (while meshing with the sun gear 81). The planetary gear 83 is also internally meshed with a ring gear 84 (integral with the transmission ring 60).

On the other hand, the torque detecting mechanism TS for detecting the torque of the crankshaft 12 mainly includes a torque ring 91, a torque arm 92, a potentiometer 94 with a cam 93, and a spring 95.

The torque ring 91 is connected to the crankshaft 12
Is connected to the crankshaft 12 through a spline 91a at the outer periphery of the gearbox, and is integrated with the sun gear 81 of the speed increaser 80 as described above.

The torque arm 92 is connected to the torque ring 91 via a spline 92a. FIG.
, The other end 92b of the torque arm 92 is connected to one end 93 of a cam 93 integrated with the potentiometer 94.
a. The other end 93b of the cam 93 is in contact with a cam receiver 95a of a spring (spring member) 95 attached to the vehicle body side 94. When torque is applied to the crankshaft 12, the torque causes the torque arm 92 to rotate in the A1 direction via the sun gear 81 and the torque ring 91 of the speed increaser 80, and the cam 93 receives the rotation, thereby causing the cam 93 to move in the direction indicated by the arrow B1 in the figure. , And the cam 93 is positioned at a position balanced with the repulsive force of the spring 95.

A movable portion (variable resistance portion), not shown, of the potentiometer 93 is integrated with the cam 93, and a predetermined resistance value corresponding to the torque of the crankshaft 12 is set according to the positioning of the cam 93. (Selected).

A known electric system (not shown) has a circuit formed so that a current corresponding to the set resistance value can be output to the armature coil 31 of the flat motor 30.

In FIG. 2, reference numerals 63, 64, 6
Reference numerals 6, 68 and 69 indicate bearings.

Next, the operation will be described.

First, the operation of the motor drive system MD will be described.

When the armature coil 31 of the flat motor 30 rotates, the spline 41 rotates via the one-way clutch 40 incorporated in the hub 31a.
When the joint spline 41 rotates once, the spline 51a
The eccentric body 51 (the input shaft of the speed reducer 50) rotates eccentrically once around the outer periphery of the crankshaft 12 (specifically, the outer periphery of the bearing 51b) through the shaft.

When the eccentric body 51 rotates once eccentrically, the external gear 52 also eccentrically swings once around its outer periphery. When the external gear 52 eccentrically swings once, the internal meshing positions of the external gear 52 and the internal gear 53 are sequentially shifted and make one round.

The internal gear 53 is fixed to the casing 26, and the external gear 52 has 43 teeth and the internal gear 53
Since the number of teeth 44 of the external gear 52 is one less than the number of teeth 44, the phase of the external gear 52 is shifted by one tooth with respect to the internal gear 53 by one rotation of the meshing position. This means that the internal gear 53
This means that the external gear 52 has rotated by -1/43 with respect to (fixed). Note that the minus sign indicates the eccentric body 51.
(The rotation direction of the armature coil 31).

The swing component of the external gear 52 is absorbed by the gap between the internal pin 55 and the internal pin hole 54, and only the rotation component of the external gear 52 is transmitted to the transmission ring 60 via the internal pin 55. .

As a result, the rotation of the eccentric body 51 (or the armature coil 31) is transmitted to the transmission ring 60 while being reduced at a reduction ratio of -1/43. The reduction ratio of 1/43 is a value that can be sufficiently satisfied as the reduction ratio necessary for reducing the rotation of the flat motor 30.

The rotation of the transmission ring 60 is transmitted to the sprocket 62 as it is.

The operation of the one-way clutch 40 will be described later.

Next, the operation of the manual drive system PD will be described.

The pedaling force (torque) of the pedal 22 is transmitted to the crankshaft 12 via the crank 24. The torque transmitted to the crankshaft 12 is transmitted to the carrier 82 of the speed increaser 80 via the one-way clutch 70. Since the sun gear 81 (integral with the torque ring 91) of the speed-increasing gear 80 is substantially fixed, the planetary gear 83 revolves around the outer periphery of the sun gear 81 when the carrier 82 rotates, and as a result, the ring gear 84 (integral with the transmission ring 60). Carrier 8
The rotation speed is increased with respect to 2. This action corresponds to a typical speed increasing action of a so-called simple planetary gear mechanism.

Since the ring gear 84 is integrated with the transmission ring 60 in this embodiment, the rotation of the ring gear 84 becomes the rotation of the transmission ring 60 as it is, and is transmitted to the sprocket 62.

Here, the operation of the one-way clutches 40 and 70 will be described.

One-way clutch 4 of motor drive system MD
When the rotation of the gearbox 50 side (the eccentric body 51) is relatively faster than the rotation of the flat motor 30 side, the idle rotation prevents the power from being transmitted. For example, when the rotation on the human power side is relatively faster than the rotation of the motor (including the stop), such as when the vehicle is running only with human power (with the motor stopped), the one-way clutch 40 idles. As a result, it is possible to prevent the running resistance from increasing due to the flat motor 30 rubbing around.

On the other hand, the one-way clutch 70 of the manual power drive system PD runs idle when rotation of the gearbox (carrier 82) is relatively faster than rotation of the crankshaft 12, thereby preventing transmission of power. I do. Thus, for example, when the driver turns the pedal (crankshaft) in the reverse direction, the rotation on the gearbox 80 side rotates on the crankshaft 12 side (reverse rotation).
Since the vehicle is relatively faster, the vehicle is idle and power transmission is interrupted. As a result, the crankshaft 12
The reverse rotation prevents the speed increaser 80, the transmission ring 60, or the speed reducer 50 and the flat motor 30 from rotating together (in the opposite direction).

If the eccentric body 51 of the reduction gear 50 rotates in a direction opposite to the normal rotation, the one-way clutch 40 of the motor drive system MD (the rotation of the flat motor 30 is smaller than that of the reduction gear 50). (Because it is relatively faster than (reverse rotation)). Therefore, the flat motor 30 can be rotated in the reverse direction as it is. However, since the one-way clutch 70 exists, even if the crankshaft 12 is rotated in the reverse direction as described above, the eccentric body 51 does not rotate in a direction opposite to the normal rotation, and therefore, the motor does not rotate in the reverse direction.

The arrangement of the one-way clutch is not limited to the above example. For example, the transmission ring 60 (although the capacity of the one-way clutch increases) may be divided into the inner pin 55 side and the sprocket 62 side, and the one-way clutch may be interposed here. If a one-way clutch is mounted at this position, not only the flat motor but also the speed reducer can be prevented from rotating when traveling with only human power.

One of the advantages of the present invention is that since the flat motor and the speed reducer are both provided coaxially with the crankshaft, the degree of freedom in the arrangement of the one-way clutch is high.

Next, the operation of the torque detecting mechanism TS will be described.

The torque of the crankshaft 12 is detected by the torque detecting mechanism TS as follows.

The torque of the crankshaft 12 is applied to the sun gear 81 via the one-way clutch 70, the carrier 82, and the planetary gear 83. The torque applied to the sun gear 81 is transmitted to a torque ring 91 integrated with the sun gear 81 and applied to a torque arm 92 via a spline 92a.

As shown in FIG.
When this torque is used to rotate in the direction A1 in the figure, the cam 93 rotates in the direction B1 and the spring 95 further rotates.
Is compressed in the C1 direction and stops in balance with the reaction force of the spring 95 in the D1 direction.

Therefore, the torque of the crankshaft 12 can be captured as the rotation angle of the cam 93. Cam 93
Is linked with the rotation of the slide bar of the variable resistor (not shown) of the potentiometer 94, so that the torque of the crankshaft 12 can be converted into a resistance value and detected.

A known electric system (not shown) controls a current flowing through the armature coil 31 of the flat motor 30 according to the resistance value.

Next, another embodiment of the present invention will be described with reference to FIG.

In this embodiment, the speed increaser of the manual drive system PD is omitted.

In the present invention, the planetary gear structure of the oscillating internal meshing type is adopted for the speed reduction mechanism.
A large (tens of) reduction ratio can be obtained. That is, since the rotation of the motor can be sufficiently reduced only by the deceleration mechanism, the rotation speed of the sprocket in the motor drive system can be reduced even if there is no gearbox of the manual drive system PD. Can easily be reduced.

In this embodiment, the human-powered driving system P
D has no gearbox, and the rotation of the crankshaft 112 is transmitted directly to the transmission ring 160 via the one-way clutch 170.

Therefore, the weight can be reduced by the absence of the gearbox, and the running resistance can be reduced.

Since the gearbox has been removed from the manual drive system PD, the torque of the crankshaft 112 cannot be detected by the displacement of the sun gear 81 as in the above embodiment. Therefore, in this embodiment, torque detection is performed using a so-called torsional displacement of a torsion bar.

As shown in FIG. 5, the torque ring (torsion bar) 191 is partially cut. Therefore, the spline 19 is attached to the torque ring 191.
When the torque of the crankshaft 112 is applied via 1a, the torque ring 191 is twisted and deformed. This variant is
Torque plate 19 inclined so as to bend in the axial direction
Rotate 2. As a result, the piston 193a moves in the axial direction by an amount corresponding to the rotation to move the slider 193b. Therefore, if the stroke (movement amount) of the slider 193b is detected by the stroke sensor 194, the torque of the crankshaft 112 can be detected. Reference numeral 195 denotes a return spring that pushes the piston 193a back toward the torque plate 192 when torque is no longer applied to the torque ring 191.

Since other configurations are the same as those of the previous embodiment, the same or similar parts in the drawings are given the same reference numerals in the last two digits as those of the previous embodiment, and duplicate explanation is omitted. I do.

The method of detecting the torque of the crankshaft regardless of the presence or absence of the gearbox is not limited to the above example. For example, when there is no gearbox, the torque may be detected by a configuration schematically shown in FIGS.

A drive body 296 integral with the crankshaft-side member (member connected to the crankshaft via a one-way clutch not shown) 212 extends in the radial direction. On the other hand, the sprocket-side member (member corresponding to the transmission ring) 260 also has a driven body 260a integrated therewith.
Are formed. The driving body 296 and the driven body 260a are connected by a spring 297. The driven body 26
A stopper 298 is provided on the 0a side. A gap X1 is provided between the stopper 298 and the driving body 296 when the spring 297 is free.

When the crankshaft-side member 212 is rotated by the pedaling force of a person, the driving body 296 integrated with the crankshaft-side member 212 presses the sprocket-side driven body 260a via the spring 297. Thus, the rotation A2 of the crankshaft side member 212 is transmitted as the rotation B2 of the sprocket side member 260. The rotation ratio is 1: 1.

Since the torque of the crankshaft-side member 212 is reflected in the compression amount of the spring 297, it is possible to detect how small the gap X1 is by, for example, a gap detection technique utilizing an electromagnetic relationship. Side member 212
(Ie, crankshaft) torque can be detected.

Here, the spring constant of the spring 297 is set to "a value at which the gap X1 becomes zero when torque corresponding to the maximum value that can be output by the motor is applied to the crankshaft". . By setting the spring constant and the gap X1 of the spring 297 in this way, it is possible to prevent the spring 297 from coming into close contact between the lines and reducing the durability even when an excessive pedaling force is applied to the crankshaft-side member 212. Further, it can also function as a mechanical stopper for preventing an excessive current from flowing to the motor side.

The driving body 296 and the driven body 260a
When a plurality of pairs are arranged in the circumferential direction, each spring 297
Etc. can be made smaller and the torque can be detected more accurately.

[0092]

As described above, according to the present invention,
A flat motor (flat DC motor) is adopted as the drive source, and this is directly incorporated on the crankshaft, and further combined with a one-stage type of oscillating internal meshing type planetary gear structure reducer to reduce the speed. Sprockets (on the crankshaft) (large gear)
Both the motor and the speed reducer can be accommodated in the range of the size, so that a very compact and lightweight device can be realized as compared with the conventional device.

Further, since the speed reducer is a single-stage type, the transmission efficiency is high, the battery consumption is correspondingly low, and the running resistance is low.

Further, since both the motor and the speed reducer are coaxially incorporated into the crankshaft, it is easy to assemble the individual members and to easily incorporate a torque detecting mechanism for detecting the torque of the crankshaft. it can.

Further, since the motor and the speed reducer are coaxially mounted on the crankshaft, a one-way clutch for switching between transmission and disconnection of the driving force can be easily installed at any place, so that the design of the transmission path is changed. Is also very advantageous.

[Brief description of the drawings]

FIG. 1 is an overall front view of an electric bicycle to which the present invention is applied.

FIG. 2 is a cross-sectional view taken along line II-II of FIG.

FIG. 3 is a sectional view taken along the line III-III in FIG. 2;

FIG. 4 is a front configuration diagram showing a torque detection mechanism.

FIG. 5 is a sectional view corresponding to FIG. 2, showing another embodiment of the present invention.

FIG. 6 is a schematic diagram for explaining another example of the torque detection mechanism.

FIG. 7 is a schematic diagram viewed from a direction indicated by an arrow VII in FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 12 ... Crankshaft 22 ... Pedal 24 ... Crank 30 ... Flat motor 32 ... Battery MD ... Motor drive system PD ... Manual drive system TS ... Torque detection mechanism 40 ... One-way clutch 50 ... Reduction gear 51 ... Eccentric body 52 ... External gear 53 ... Internal gear 54 ... Inner pin hole 55 ... Inner pin 60 ... Transmission ring 62 ... Sprocket 70 ... One-way clutch 80 ... Speed increaser

Claims (5)

[Claims] A sprocket which has a human drive system and a motor drive system and is incorporated coaxially with a crankshaft and connected to a rear wheel is rotated by a motor in addition to a pedal force by a human. An electric bicycle comprising: a flat motor having an output shaft coaxial with the crankshaft; and a speed reducer for reducing rotation of the flat motor and transmitting the reduced rotation to the sprocket. An eccentric body that is rotated by the rotation of the external gear, an external gear that is incorporated so as to swing and rotate with respect to the crankshaft through the eccentric body, and an internal gear that is inscribed while the external gear swings. ,
A single-stage oscillating internally meshing planetary gear structure mainly composed of a transmission ring connected to the external gear and to the sprocket via a mechanism for taking out only the rotation component of the external gear; An electric bicycle comprising: a reduction gear; and the reduction gear and the flat motor are both disposed on the crankshaft, coaxially with the crankshaft, and between the pedals. 2. The one-way clutch according to claim 1, wherein the one-way clutch is engaged between the flat motor and the eccentric body only when the rotation on the flat motor side is relatively faster than the rotation on the eccentric body side. An electric bicycle characterized by intervening. 3. The crank according to claim 1, wherein the human-powered drive system is provided around the crankshaft, the crank transmitting the pedaling force by the human to the crankshaft, and the rotation on the crankshaft side is smaller than the rotation on the sprocket side. A one-way clutch that is engaged only when the speed is relatively high to allow transmission of power, and a speed-increasing gear that transmits the rotation of the crankshaft to the sprocket side at an increased speed, which is provided on the outer periphery of the crankshaft. A sun gear, a carrier that rotates with the rotation of the crankshaft, a planetary gear supported by the carrier and revolving around the outer periphery of the sun gear, and a ring gear that is inscribed in the planetary gear and connected to the transmission ring. A torque arm rotatable integrally with the sun gear; and a torque arm attached to the vehicle body. A spring member that receives the rotational force and permits the rotational displacement of the torque arm by an amount commensurate with the rotational force, and a torque detection mechanism that detects torque on the crankshaft by the rotational displacement of the torque arm. An electric bicycle characterized by the following. 4. The electric bicycle according to claim 3, wherein a link gear of the speed increaser of the manual drive system is disposed integrally with the transmission ring on an inner peripheral side of the transmission ring. 5. The power transmission system according to claim 1, wherein the manual drive system is provided around a crankshaft, and engages only when the rotation of the crankshaft is relatively faster than the rotation of the sprocket. And transmit the torque of the crankshaft to the sprocket via a one-way clutch,
An electric bicycle wherein a torsion bar type torque detecting mechanism for detecting torque of the crankshaft is incorporated on the crankshaft.