JPH09109985A - Driving auxiliary device for bicycle equipped with driving auxiliary power - Google Patents

Abstract

PROBLEM TO BE SOLVED: To exactly control assist ratio due to driving auxiliary force from an electric motor to a predetermined or an arbitrary ratio by detecting difference in strength between two thrust components of force and by controlling output from the electric motor to lead the difference in strength to specific or arbitrary difference in strength. SOLUTION: Torque cams 55, 56 act two thrust components of force p, m having strength being in proportion to pedal leg-powder P and driving auxiliary force M on the resultant force frame 47 of a resultant force rotating member 45 from both right and left sides. An assist ratio, coming not to 1:1, inequalizes the strength of the two thrust components of force, p, m. Thus, the resultant force rotating member 45 is pressed against the thrust component of force, p or m, having higher strength to move to the axis direction of a crank shaft 4. A position sensor 67 reads moving direction and movings from the neutral position C of the resultant force rotating member 45. A control device detects difference in strength between the two thrust components of force p, m based on input from the position center. Output from an electric motor is controlled to lead the difference to 0.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mounts a drive assisting device having an electric motor and a resultant device on a bicycle body,
The present invention relates to a bicycle with drive assisting force, which assists pedaling force with the drive assisting force of the electric motor to facilitate uphill traveling and traveling while receiving head wind.

[0002]

2. Description of the Related Art A force combiner incorporated in the above drive assist device combines the pedal effort of an occupant applied to a crankshaft and the drive assist force of an electric motor and transmits the resultant force to the drive wheels. A planetary gear device and a differential device are widely used.

When the pedaling force and the drive assisting force are combined by this resultant device, the assist ratio by the drive assisting force,
That is, the output of the electric motor is controlled so that the ratio of the pedal effort and the drive assist force is always constant, preferably the assist ratio is always 1: 1 so that the feeling of stepping on the pedal is natural. It is necessary to maintain a good riding feeling of the attached bicycle. In this case, special care must be taken so that the driving assistance force does not exceed the pedal effort in any case.

In the conventional drive assisting device, the pedaling force is detected by a dedicated detecting means (torque sensor or the like), and the signal is input to a control device (small CPU or the like), which adjusts the pedaling force to the pedaling force. The electric current supplied to the electric motor is controlled by setting the assist ratio to 1: 1 or an arbitrary ratio.

[0005]

However, the accuracy of the detection means for detecting the pedaling force, the output characteristics of the electric motor with respect to the current value, the friction loss of the resultant device, and the like are slightly different from one another. If these small differences are accumulated, the assist ratio easily changes.

Therefore, in order to accurately set the assist ratio to 1: 1 or an arbitrary ratio, not only the accuracy of the pedal depression force detecting means, but also the output characteristics of the electric motor, friction loss of the resultant device, etc. are strictly checked. However, an inspection process of checking the output of the electric motor again after assembling the entire drive assist device is required, which inevitably leads to a decrease in productivity of the drive assist device and a great increase in cost.

Moreover, even if the assist ratio is 1: 1 under the condition that the battery is correctly charged in a new vehicle, if the battery is overcharged and the output of the electric motor is improved, or the running-in operation is performed. If the friction loss of the resultant device is reduced and the output of the electric motor is relatively improved later, the drive assist force may exceed the pedal effort, so the assist ratio does not necessarily become 1: 1.

If the driving assist force exceeds the pedal effort,
To avoid this situation, the output of the electric motor is set to a small value in advance, and the battery is overcharged, in addition to the unnatural driving feeling of the bicycle with driving assistance and the acceleration force that is not expected by the occupants. It is necessary to prevent the drive assist force from exceeding the pedal effort even when the friction loss of the resultant force device is reduced.

However, if the output of the electric motor is set to a small value in advance in case the battery is overcharged or the friction loss of the power unit is reduced, it is possible to reduce the friction loss of the power unit when the battery is properly charged. When the vehicle is large, the output of the electric motor becomes too low, and the assist ratio cannot be maintained at 1: 1.
When the voltage of the battery is decreasing, the output of the electric motor is further weakened, and the assist ratio is further reduced.

The present invention has been made to solve such a problem, and can accurately control the assist ratio by the drive assisting force of the electric motor to 1: 1 or an arbitrary ratio, and further, to produce it. An object of the present invention is to provide a drive assisting device for a bicycle with drive assisting force, which can improve the property and reduce the cost.

[0011]

In order to achieve the above object, a bicycle with driving assistance force according to the present invention is provided with a resultant force device for synthesizing a pedaling force of an occupant and a driving assistance force of an electric motor around a crankshaft. A drive sprocket that is rotatably supported to wind the drive chain is provided integrally with the rotation, and an output rotation member that transmits the resultant force of the pedal depression force and the drive assist force to the drive wheel side through the drive chain, and the output rotation member. A member-rotating member provided integrally with the member via an axial moving means and movably in the axial direction, and a pedal depression force and a drive assisting force are transmitted to the resultant force rotating member, and at the same time, a pedal depression force and a drive assisting force are transmitted. Component generating means for exerting two thrust component forces having a strength proportional to the force from both sides of the resultant rotating member along the axial direction of the crankshaft, and a resultant rotating member. An urging means for keeping the axial movement range at the neutral position, and a position sensor for detecting the movement direction and the movement amount from the neutral position of the resultant rotary member which moves in the axial direction by receiving the two thrust component forces are provided. The position detection point of the position sensor is arranged at a point which is orthogonal to the tension side chain line of the drive chain and coincides with a reference plane passing through the center line of the crankshaft, and based on the input from the position sensor. The strength difference between the above two thrust components is detected, and this strength difference is set to 0.
And a control device for controlling the output of the electric motor so as to obtain an arbitrary strength difference.

[0012]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a drive assist device that is mounted on a body frame of a bicycle with drive assist force and configured to assist the pedal effort of an occupant by the drive assist force of an electric motor provided therein. 2 is a longitudinal sectional view of the drive assist device taken along the line II-II in FIG. FIG. 3 is a right side view of the drive assist device.

The casing 2 forming the outer shell of the drive assisting device 1 is made of, for example, an aluminum alloy, and as shown in FIG. 1, a left case 2L located on the left side, a middle case 2M located in the center, and a right case on the right side. The light case 2R located is fixed by several bolts 3 penetrating in the vehicle width direction. Note that FIG. 2 shows a state in which the left case 2L is removed.

A crankshaft 4 extending in the vehicle width direction is rotatably supported at the rear portion of the casing 2, and cranks 5L and 5R are fixed by bolts 6 to both ends of the crankshaft 4 protruding left and right from the casing 2. To be done. Crankshaft 4
Is rotatively driven in the direction indicated by arrow A when a pedal (not shown) provided at the tips of the cranks 5L and 5R is stepped on by an occupant's foot.

On the other hand, an electric motor 7 is installed in the front part of the casing 2. This electric motor 7 generates a driving assist force, and its outer case 8 is fixed to the middle case 2M side by several bolts 9, and the main shaft 10 of the electric motor 7 is parallel to the crankshaft 4. . This spindle 10
Rotates in the direction indicated by arrow B.

A reduction gear train 12 is provided on the left side of the casing 2. This reduction gear train 12 is positioned on the main shaft 10 of the electric motor 7 so as to rotate integrally with the main drive gear 13, a primary driven gear 14 meshing with the primary drive gear 13, and a left side of the primary driven gear 14. By the action of the one-way clutch 15, a secondary drive gear 16 that is integrally rotated with the primary driven gear 14 only when the electric motor 7 is operated, a secondary driven gear 17 that meshes with the secondary drive gear 16, and a right side of the secondary driven gear 17. It is composed of a tertiary drive gear 18 provided integrally with the rotation, and a large-sized tertiary driven gear 19 provided near the left end of the crankshaft 4 and meshing with the tertiary drive gear 18.

Then, in the intermediate portion of the crankshaft 4, a force combining device is provided.
21 is mounted. FIG. 4 is an enlarged vertical sectional view of the resultant device 21. The resultant device 21 is configured as follows, for example.

First, a substantially cylindrical pedal depression force transmitting member 22 is provided on the outer periphery of the middle portion of the crankshaft 4 as a pair of metal bearings 23, 2.
It is rotatably supported via 4. The diameter of the right end portion of the pedal effort transmission member 22 is enlarged to form a clutch housing 25, and a one-way clutch 26 is provided inside the clutch housing 25. The one-way clutch 26 transmits only the rotation of the crankshaft 4 in the A direction to the pedal depression force transmission member 22, and when the crankshaft 4 reverses or when the pedal depression force transmission member is rotated.
When the rotation speed of 22 exceeds the rotation speed of the crankshaft 4, the clutch is disengaged.

Further, a drive assisting force transmitting member 27 formed in a cup shape is rotatably provided on the outer periphery of the left end portion of the pedal depression force transmitting member 22 and is axially mounted while its axial movement is restricted by a circlip 28. Has been done. This drive assist force transmission member
The third driven gear 19 is rotatably connected to the left end of 27 by spline connection or the like. Therefore, the rotation of the tertiary driven gear 19, that is, the rotation in which the drive assisting force of the electric motor 7 is decelerated, remains as it is.
It is transmitted to.

On the other hand, an output rotary member 31 is rotatably supported by a bearing 32 near the right end of the crankshaft 4.
This output rotary member 31 is located on the right side of the output housing.
33 and the output sleeve 34 located on the left side, and the joint flanges 35, 36 formed at the joints of both parts 33, 34 are assembled by being fastened with six bolts 37. ing.

As shown in FIG. 2, a plurality of inner peripheral spline grooves 38 extending in the axial direction are formed on the inner peripheral surface of the output sleeve 34. Also, output housing 33 and output sleeve
A steel plate ball stopper 41 is sandwiched between the output sleeve 34 and 34, and a steel plate ball stopper 42 is also fixed to the left end portion of the output sleeve 34 using a circlip 43.

A resultant force rotating member 45 is provided inside the output rotating member 31. This resultant force rotating member 45 is a member in which a donut disk-shaped resultant flange 47 is integrally provided at the left end of a cylindrical resultant sleeve 46 located inside the output sleeve 34, and further on the left side thereof is an annular sensor. A ring 48 is provided integrally with the rotation. The pedal effort transmission member 22 is loosely inserted into the inner diameter of the resultant flange 47, and a sensor groove 49 is formed on the outer periphery of the sensor ring 48.

A plurality of outer peripheral spline grooves 51 extending in the axial direction are formed on the outer peripheral surface of the resultant sleeve 46, and a steel ball is formed between the outer peripheral spline grooves 51 and the inner peripheral spline groove 38 of the output sleeve 34. The ball splines 53 are formed by arranging 52. Both ends of the row of steel balls 52 are held by the ball stoppers 41 and 42, thereby preventing the steel balls 52 from being pulled out from the inner and outer spline grooves 38 and 51. Due to the ball splines 53, the resultant rotation member 45 is integrally rotated with the output rotation member 31, and is relatively movable in the axial direction. The ball spline 53 serves as the axial moving means described in claim 1.

Further, the resultant flange 47 of the resultant rotary member 45.
A torque cam 55 is provided between the clutch pedal 25 and the clutch housing 25 of the pedal effort transmission member 22, and a torque cam 56 is provided between the resultant flange 47 and the drive assist force transmission member 27. These torque cams 55, 56 serve as the component force generating means described in claim 1, and are provided on the inner peripheral side of the ball spline 53.

As shown in FIG. 5, the torque cam 55 on the right side is formed on the right side surface of the resultant flange 47 with an inner cam 57 having a sloped cam shape, and is formed on the left side surface of the clutch housing 25 so as to mesh with the inner cam 57. It is composed of an outer cam 58. The left torque cam 56 includes an inclined cam-shaped inner cam 59 provided on the left side surface of the resultant flange 47 and an outer cam 60 formed at the right end of the drive assist force transmission member 27 and meshing with the inner cam 59. It is configured.

The cam shapes of the left and right torque cams 55 and 56 are symmetrical with the resultant force flange 47 interposed therebetween. The cam shape of the right torque cam 55 is such that when the pedal depression force transmission member 22 receives rotation of the crankshaft 4 (pedal depression force) and rotates in the A direction, the pedal depression force P is transmitted to the resultant force flange 47 as indicated by a vector. At the same time, a thrust component force p having a strength proportional to the pedal effort P is generated, and the thrust component force p presses the resultant force flange 47 to the left.

On the other hand, the cam shape of the left torque cam 56 is
When the drive assisting force transmitting member 27 receives the drive assisting force of the electric motor 7 and rotates in the direction A, the drive assisting force M is transmitted to the resultant force flange 47 and, at the same time, the thrust having a strength proportional to the drive assisting force M is transmitted. A force component m is generated, and this thrust force component m
Is shaped so as to press the resultant flange 47 to the right.

Further, a pair of left and right coil springs 62, 63 are provided on the inner peripheral side of the torque cams 55, 56. These coil springs 62 and 63 serve as the urging means described in claim 1. Right coil spring 62
Is mounted between the resultant force flange 47 and the clutch housing 25 of the pedal effort transmission member 22, and the left coil spring 63
Is mounted between the resultant force flange 47 and the drive assist force transmitting member 27. The left and right coil springs 62 and 63 have the same shape and spring constant.

The pedal depression force transmitting member 22 (the clutch housing 25 thereof) and the drive assisting force transmitting member 27 are immovable in the axial direction of the crankshaft 4, and the resultant flange 47 between them is actuated by the ball spline 53. Since it is movable in the axial direction, when the resultant flange 47 is pressed from both sides by the two coil springs 62 and 63 having even urging force, the position C where the coil springs 62 and 63 have the same length C And the urging forces of the coil springs 62 and 63 are balanced,
The resultant force flange 47 stops. This position C is the resultant rotation member
It is a neutral position of 45, and is set to be an intermediate point of a range (a movable range of the ball spline 53) in which the resultant force rotating member 45 can move in the axial direction of the crankshaft 4.

The output housing 33 of the output rotary member 31
A sprocket boss 64 is formed at the right end, and the sprocket boss 64 projects outward from the right side surface of the casing 2, and the drive sprocket 65 is rotationally fixed to this part by a connecting means such as a spline or screw. ing. A drive chain 66 is wound between the drive sprocket 65 and a driven sprocket provided on the rear wheel (not shown) of the bicycle with driving assistance force.

On the other hand, a position sensor 67 is fixed to the rear portion of the bottom surface of the casing 2 with bolts 68. The position sensor 67 is provided with a rotating arm 69 on the upper surface thereof, and a miniature bearing 70 rotatably supported at the tip of the rotating arm 69 is provided with a sensor groove 49 of a sensor ring 48.
It is tightly and slidably fitted inside.

When the resultant force rotating member 45 moves in the axial direction of the crankshaft 4, the sensor ring 48 also moves in the axial direction together with the resultant force rotating member 45, so that the rotating arm 69 of the position sensor 67 rotates to cause a resultant force rotation. The movement direction and the movement amount of the member 45 from the neutral position C are detected.

Here, as shown in FIG. 3, when a reference plane D passing through the center line of the crankshaft 4 orthogonal to the tension side chain line 66a of the drive chain 66 is assumed, the miniature which is the detection point of the position sensor 67. Bearing 70
Is arranged at a point E coinciding with the reference plane D. The rotating arm 69 of the position sensor 67 is set so as to be perpendicular to the reference plane D when the resultant rotating member 45 is in the neutral position C. Also, like the point E, the reference plane D
The position sensor 67 may be provided so that the miniature bearing 70 is arranged at the point F corresponding to.

The resultant device 21 is configured as described above, and the drive assist device 1 is further provided with a controller 72 (not shown in the drawings other than FIG. 6). As shown in FIG. 6, a position sensor 67 is electrically connected to the control device 72, and data of the moving direction and the moving amount of the resultant rotation member 45 measured by the position sensor 67 is used as the control device.
It is supposed to be input to 72. The control device 72 is electrically connected to the electric motor 7, a battery unit 73 that serves as a power source of the electric motor 7, a device such as a rotation speed sensor 74, and the like.

The rotation speed sensor 74 is a sensor fixed to the left side surface of the middle case 2M with a bolt 75 as shown in FIG. Further, for example, on the left side of the tertiary driven gear 19, a disc-shaped rotation sensor plate 76 is provided so as to rotate integrally with the crankshaft 4.
The rotation speed sensor 74 reads the movement of the uneven shape 77 provided at regular intervals on the outer peripheral portion of the crankshaft 4 by
Is detected, and the data is input to the control device 72.

Next, the operation of the drive assist device 1 thus constructed will be described.

When the bicycle with drive assisting force is running, the crankshaft 4 receives the pedaling force of the occupant and rotates in the direction A. The rotation of the crankshaft 4 passes through the one-way clutch 26 of the force combiner 21 and the pedaling force transmitting member 22. And the pedal effort transmission member 22 rotates in the A direction. On the other hand, electric motor 7
The drive assisting force is reduced by the reduction gear train 12 and transmitted to the drive assisting force transmitting member 27, and the drive assisting force transmitting member 27 also rotates in the A direction. The rotational force of the pedal depression force transmission member 22 and the driving assist force transmission member 27 is transmitted to the resultant force flange 47 of the resultant force rotation member 45 via the torque cams 55 and 56, and the resultant force rotation member 45 outputs the output rotation member 31 via the ball spline 53. Is rotated in the A direction.

The rotational force of the output rotary member 31 is the resultant force of the pedal effort of the occupant and the drive assisting force of the electric motor 7. The resultant force is output from the drive sprocket 65 and the drive assisting force is applied via the drive chain 66. Output to the drive wheels (rear wheels) of the bicycle. For this reason, the pedal effort is assisted by the drive assist force of the electric motor 7, and the bicycle with the drive assist force can be easily traveled even with a small pedal effort.

The torque cams 55 and 56 are pedal force transmitting members.
At the same time as transmitting the rotational force of 22 and the drive assisting force transmission member 27 to the resultant force rotating member 45, two thrust component forces p, having strengths proportional to the pedal effort P and the drive assisting force M as shown by the vector in FIG. m is the resultant flange 47 of the resultant rotary member 45.
As a result, the resultant force flange 47 is pressed from both the left and right sides by the thrust component forces p and m.

When the ratio of the pedal depression force P to the drive assisting force M, that is, the assist ratio is 1: 1, the strengths of the two thrust component forces p and m acting on both sides of the resultant flange 47 are also equal. 4, 5 and 7 as they cancel each other out.
As shown in (B), the position of the resultant rotation member 45 is kept at the neutral position C.

However, when the assist ratio is not 1: 1, the strengths of the two thrust component forces p and m become unequal, so that the resultant force rotating member 45 presses the thrust component force p or m of the stronger one. Then, the crankshaft 4 is moved in the axial direction.
For example, if the pedal effort P is stronger than the drive assist force M,
Since the thrust component force p of the pedal depression force P becomes stronger than the thrust component force m of the drive assist force M, the resultant force rotating member 45 is pressed by the thrust component force p, and the neutral position C as shown in FIG. 7 (A).
Move to the left than.

If the driving assistance force M is stronger than the pedal depression force P, the thrust component force m of the driving assistance force M becomes stronger than the thrust component force p of the pedal depression force P, so that the resultant force rotating member.
45 is pushed by the thrust force m and moves to the right of the neutral position C as shown in FIG. 7 (C).

The neutral position C of the resultant force rotating member 45
The movement direction and the movement amount from are read by the position sensor 67, and the data is input to the control device 72. Based on the input from the position sensor 67, the control device 72
Detects the strength difference between the two thrust components p and m, and this difference is 0
The output of the electric motor 7 is controlled so that That is,
When the resultant rotation member 45 moves to the left of the neutral position C as shown in FIG. 7 (A), the output of the electric motor 7 is improved,
When the resultant force rotating member 45 moves to the right of the neutral position C as shown in FIG. 7C, the output of the electric motor 7 is controlled to be reduced.

As a result, in the resultant force device 21, the resultant force rotation member 45 is maintained in the neutral position C as shown in FIG. 7 (B), and the assist ratio is always maintained at 1: 1. It should be noted that the assist ratio can be set not only to 1: 1 but also to any ratio by making the controller 72 arbitrarily set the strength difference between the two thrust component forces p and m. For example, when the strength difference between the two thrust components p and m is set to 1: 0.5, the driving assist force M becomes half the pedal depression force P.

It is also possible to continuously change the ratio of this intensity difference during traveling. For example, when starting a bicycle with driving assistance, set the assist ratio to 1: 1 of the maximum ratio,
If the assist ratio is lowered as the vehicle speed increases, it is possible to significantly reduce the power consumption of the electric motor 7 while reducing the burden of human power, and to suppress the discharge amount of the battery unit 73 to greatly extend the traveling distance. it can.

Further, the control device 72 determines the vehicle speed from the rotation speed of the crankshaft 4 input from the rotation speed sensor 74, and when the vehicle speed exceeds a certain level, the electric motor 7
Reduce the power supply to the vehicle or set it to 0 to prevent the vehicle speed from becoming excessive.

If the drive assisting device 1 is configured as described above, the resultant device 21 that combines the pedal effort and the drive assisting force
Since the assist ratio is directly and mechanically detected at the portion, the assist ratio can be accurately calculated without error. For this reason, there is no need to once detect the pedal depression force applied to the crankshaft 4 and control the output of the electric motor 7 in accordance therewith as in the conventional case, and a detection unit such as a torque sensor for detecting the pedal depression force is unnecessary. Become.

Therefore, it is not necessary to consider the error of the pedal depression force detecting means, and the assist ratio is set to 1: 1 or an arbitrary ratio based on the net output of the electric motor 7. It is possible to accurately and easily control the assist ratio, without variations in output characteristics, the charge state of the battery unit 73, or changes in friction loss of the resultant device 21 before and after the break-in operation that affect the assist ratio. it can.

Moreover, since the position sensor 67 only needs to read the strength difference between the thrust component forces p and m, which are significantly smaller than the absolute values of the pedal effort and the drive assist force, the reading error of the position sensor 67 is extremely large. It is possible to reduce the size, which also facilitates accurate control of the assist ratio.

Then, as in the conventional case, the output characteristics of the electric motor 7 and the friction loss of the resultant device 21 are strictly checked, all the drive assisting devices 1 are assembled, and then the output of the electric motor 7 is checked again. Since the process can be omitted, the productivity of the drive assist device 1 can be dramatically improved and the cost can be reduced.

If, for example, the operability of the left and right torque cams 55, 56 of the resultant force device 21 is different or the spring constants of the left and right coil springs 62, 63 are different, the neutral force rotating member 45 is neutralized. It is conceivable that the position C may shift slightly and the assist ratio may change. In that case, the shifted neutral position C
Accordingly, the assist ratio can be accurately returned to 1: 1 simply by resetting the neutral reading value of the position sensor 67, and therefore the maintainability is very good.

In the drive assist device 1, the miniature bearing 70, which is the detection point of the position sensor 67, is connected to the center line of the crankshaft 4 orthogonal to the tension side chain line 66a of the drive chain 66, as described above. Since it is arranged at the point E or the point F that coincides with the reference plane D passing through, the following effects are brought about.

That is, since the drive sprocket 65 around which the drive chain 66 is wound is provided on the rightmost side of the force combining device 21, when the drive sprocket 65 is rotationally driven by the combined force of the pedal effort and the drive assisting force,
Due to the chain tension of the tension-side chain line 66a, a moment is generated that attempts to rotate the entire force synthesizer 21 clockwise in plan view. Therefore, the sensor ring 48 of the force combiner 21 is slightly inclined such that its front side (point G in FIG. 3) is to the right and its rear side (point H) is to the left.

Therefore, when the miniature bearing 70 of the position sensor 67 is arranged at the G point or the H point, the position sensor 67 detects all the inclination of the sensor ring 48 due to the influence of the chain tension. The neutral position C of the resultant rotary member 45 is deviated depending on the presence or absence of tension, and the assist ratio becomes inaccurate.

However, since the sensor ring 48 is inclined about the points E and F which the reference plane D crosses, the points E and
At point F, the amount of movement of the sensor ring 48 to the left and right becomes zero. Therefore, by disposing the miniature bearing 70 of the position sensor 67 at the E point or the F point as in this embodiment, the position sensor 67 does not detect the inclination of the sensor ring 48 due to the chain tension, and it depends on the presence or absence of the chain tension. Since the deviation of the neutral position C is eliminated, the assist ratio can be controlled more accurately.

In the present embodiment, the torque cams 55 and 56, which are the component force generating means of the force combiner 21, are configured as slide type slope cams, but the present invention is not limited to this, and for example, roller type slope cams and outer circumferences. A torque cam in which an inner cam formed in the shape of a helical gear and an outer cam formed in the shape of a helical gear engage with each other may be used. Further, in the present embodiment, the biasing means of the force combiner 21 is the coil springs 62, 63, but springs of other forms may be used.

[0057]

As described above, in the drive assist device for a bicycle with drive assist force according to the present invention, the resultant force device for combining the pedal effort of the occupant and the drive assist force of the electric motor is rotated around the crankshaft. A drive sprocket that is rotatably supported around which the drive chain is wound is provided integrally with the rotation, and an output rotation member that transmits the resultant force of the pedal depression force and the drive assist force to the drive wheels via the drive chain,
The output rotary member is rotatably integrated with the output rotary member via the axial movement means, and the resultant force rotating member is provided so as to be movable in the axial direction. Component force generating means for exerting two thrust component forces having a strength proportional to the driving assist force from both sides of the resultant force rotating member along the axial direction of the crankshaft, and the resultant force rotating member is kept at a neutral position in the axial movement range. A biasing means and a position sensor for detecting the moving direction and the moving amount from the neutral position of the resultant rotary member that moves in the axial direction by receiving the two thrust component forces are provided, and the detection point of the position sensor is provided. Is arranged at a point which is orthogonal to the tension side chain line of the drive chain and coincides with the reference plane passing through the center line of the crankshaft,
A control device is provided which detects the strength difference between the two thrust component forces based on the input from the position sensor and controls the output of the electric motor so that the strength difference becomes 0 or an arbitrary strength difference. It is what

According to this structure, the assist ratio can be detected directly and mechanically in the part of the resultant device, so that the assist ratio can be accurately determined without any error, and the assist ratio can be calculated based on the net output of the electric motor. Since the ratio is set to 1: 1 or an arbitrary ratio, variations in the output characteristics of the electric motor, the state of charge of the battery unit, or changes in friction loss of the power combiner before and after running-in affect the assist ratio. The assist ratio can be controlled accurately and easily without giving it.

Moreover, since only the strength difference between the two thrust component forces, which is significantly smaller than the absolute values of the pedal effort and the drive assist force, needs to be read by the position sensor, the reading error of the position sensor can be made very small. You can
Also from this, the assist ratio can be accurately controlled.

Further, it is possible to omit the inspection process of checking the output characteristics of the electric motor, the friction loss of the resultant device, and the like, and checking the output of the electric motor again after assembling all the drive assist devices, as in the prior art. Therefore, the productivity and cost of the drive assist device can be improved.

Moreover, since the detection point of the position sensor is arranged at a point which is orthogonal to the tension-side chain line of the drive chain and coincides with the reference plane passing through the center line of the crankshaft, the resultant force of the chain tension device can be adjusted. The position sensor does not detect a slight inclination, and the assist ratio can be controlled more accurately.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a drive assist device.

FIG. 2 is a vertical cross-sectional view of the drive assist device taken along the line II-II of FIG.

FIG. 3 is a right side view of the drive assist device according to the embodiment of the present invention.

FIG. 4 is an enlarged vertical sectional view of the resultant device.

FIG. 5 is a partial cross-sectional view showing the structure of a torque cam of the force combiner.

FIG. 6 is a block diagram showing a control system of the drive assist device.

FIG. 7 is a vertical sectional view showing an operating state of the force combiner, where (A) shows a case where the pedal effort is stronger than the drive assist force, (B) shows a case where the pedal effort and the drive assist force are equal, C) shows the case where the driving assistance force is stronger than the pedal effort.

[Explanation of symbols]

1 Drive Auxiliary Device 4 Crank Shaft 7 Electric Motor 21 Combiner 31 Output Rotating Member 45 Combined Rotating Member 53 Ball Spline as Axial Moving Means 55,56 Torque Cam 62 as Component Force Generating Means 62,63 Coil Spring as Energizing Means 65 Drive sprocket 66 Drive chain 66a Drive chain tension side chain line 67 Position sensor 70 Miniature bearing that serves as detection point of position sensor 72 Control device C Neutral position of resultant rotary member D Crank orthogonal to drive chain tension side chain line Reference planes E and F that pass through the center line of the shaft Point that coincides with reference plane D P Vector showing pedal effort M Vector showing driving assistance force p Vector showing thrust component force having strength proportional to pedal effort m Driving assistance A thrust force component having a strength proportional to Torr

Claims (1)

[Claims] 1. A combined force device that combines a crankshaft 4 that is rotationally driven by a pedal effort, an electric motor 7 that generates a drive assistance force, the pedal effort and the drive assistance force, and outputs the resultant force to the drive wheel side. In a drive assisting device 1 for a bicycle with drive assisting force, the drive force chain 21 is rotatably supported around a crankshaft 4.
A drive sprocket 65 around which the 66 is wound is provided integrally with the rotation, and an output rotary member 31 that transmits the resultant force of the pedal depression force and the drive assist force to the drive wheels via the drive chain 66, and the output rotary member 31 in the axial direction. At the same time as transmitting the resultant force rotating member 45 provided integrally rotatably and axially movably through the moving means (ball spline 53) to the resultant force rotating member 45, the pedal force P And having a strength proportional to the driving assistance force M 2
Component force generating means (torque cams 55, 56) for applying two thrust force components p, m from both sides of the resultant force rotating member 45 along the axial direction of the crankshaft 4, and a neutral position of the resultant force rotating member 45 in the axial movement range. Energizing means to keep C (coil spring 6
2, 63) and a position sensor 67 for detecting the moving direction and the moving amount from the neutral position C of the resultant force rotating member 45 which receives the two thrust component forces p and m in the axial direction. , The detection point of the position sensor 67 (miniature bearing 70) to the drive chain
Crankshaft 4 orthogonal to the tension side chain line 66a of 66
Is arranged at a point that coincides with the reference plane D passing through the center line of, and the strength difference between the two thrust component forces p and m is detected based on the input from the position sensor 67, and this strength difference is set to 0 or arbitrary. 2. A drive assist device 1 for a bicycle with drive assist force, comprising a control device 72 for controlling the output of the electric motor 7 so as to obtain a difference in strength.