JPH09138168A - Torque detector and bicycle with auxiliary power device using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of metal fatigue and peeling of a resistor off a distortion causing body by transmitting operation of an operating body, which makes a distortion gate operate the distortion causing body with a to-be-detected torque, with an elastic body in between, for preventing sudden generation of bending force of the distortion causing body so that the operation of the operating body is not directly applied to the distortion causing body. SOLUTION: Under the condition that a power device is fixed to a car body, an operating body 140 of a torque detector 100 is supported, in horizontal direction, in a guide hole 126, so that, not moved in the direction that the bending force is added to a distortion causing body 131 against the vibration in the vertical direction of the car body at recessed and protruded parts of a road surface during traveling, so that the detector 100 does not malfunction. When operating force exceeds a specified value, a deflection plate 95 is moved, and the bending force of the distortion causing body 131 is reduced through the operating body 140 and a coil spring 150, and the distortion causing body 131 is restored and drives an electric motor according to resistor variation of a bridge. Since the operating body 140 presses the distortion causing body 131 through the spring 150, not directly press, it is not bent suddenly, so that breakage due to metal fatigue and peeling of the resistor are prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque detector using a strain gauge, and a torque detector for detecting a torque applied to a crankshaft by human power during human power traveling, and traveling when the torque exceeds a predetermined value. The present invention relates to a bicycle with an auxiliary power unit that includes an auxiliary power unit that assists power.

[0002]

2. Description of the Related Art As a torque detector for detecting torque using a strain gauge, for example, as disclosed in Japanese Patent Publication No. 6-96386, a steering for detecting steering torque of an electric power steering apparatus. It is used as a torque detector. The torque detector described in this publication is "effect of the invention" in the right column of page 4 of this publication.
As described in the section 1), the strain gauge may be formed on the flat plate cantilever, and even if the strain gauges used as the resistance bridge circuit are attached, the strain gauges can be easily and uniformly formed. Therefore, a large output having high noise resistance and drift resistance can be obtained, and the reliability of the output can be improved. However, in the torque detector described in the above publication, the other end of the cantilever whose one end is fixed to the housing, that is, the free end is directly contacted with the flange formed on the sliding member that slides in the axial direction on the output shaft. Since the cantilever is configured to apply bending or bending stress, the cantilever is pressed by the flange that directly abuts and repeatedly bends, which causes the metal fatigue and breakage, and the attached strain gauge has a drawback.

Further, in a bicycle with an auxiliary power unit,
When the torque applied to the crankshaft via the pedal exceeds a predetermined value while driving manually, that is, when the user is stepping on the pedal with the human power, for example, when approaching an uphill slope, the torque detector indicates that the torque exceeds the predetermined value. The driving force is detected and the auxiliary power unit is operated to assist the running force. In general, the torque detector is composed of a variable resistor, and the resistance value of the variable resistor is changed by an actuating body that operates when the torque applied to the crankshaft in human power traveling exceeds a predetermined value. , The auxiliary power unit is operated.

However, in the torque detector using the variable resistor as described above, the torque applied to the crankshaft frequently changes during traveling, so that the sliding contact causes abrasion of the resistance film. However, if it is used for a long period of time, its operation becomes inaccurate, and there arises a problem that the power unit cannot operate at a predetermined torque value applied to the crankshaft and power cannot be accurately assisted.

[0005]

As described above, in the torque detector using the conventional strain gauge, the output shaft, that is, the flange is directly brought into contact with the other end side of the cantilever whose one end side is fixed. Since the cantilever is configured to bend, the force of the output shaft is suddenly applied to the cantilever, and the cantilever that repeatedly bends due to this sudden force causes metal fatigue and breaks. There is a problem of peeling off. In addition, the torque detector composed of a variable resistor used in a bicycle with an auxiliary power unit frequently changes the torque applied to the crankshaft during running, and the sliding contact causes the resistance film to wear. However, if it is used for a long period of time, its operation becomes inaccurate, and the auxiliary power unit cannot operate at a predetermined torque value, so that power cannot be accurately assisted.

[0006]

The present invention has been made in view of the above circumstances, and the invention according to claim 1 is to solve the problem of a torque detector using a conventional strain gauge.
A case in which a guide hole is formed, an actuator that is movably disposed in the guide hole and operates by receiving an acting force of a detected torque, and a thin film resistor is formed on the surface of the strain generating body to form a bridge. And a strain gauge provided with the fixed end fixed to the guide hole and the elastic body transmitting the acting force received by the actuating body to the free end. Is a torque detector equipped with
The invention according to claim 2 solves the problem of the conventional torque detector in the bicycle with the auxiliary power unit.
An electric motor, a power transmission means that is arranged in a case and includes a plurality of gears including an output gear and that transmits the rotational force of the electric motor, and a bearing is rotatably attached to the case via a bearing, and one end side is the output gear. A hollow shaft that is connected and has a sprocket attached to the other end, and a crank that is rotatably supported inside the hollow shaft and that is provided through the hollow shaft and that has cranks with pedals at both ends. A shaft, a conversion unit that operates according to the difference between the torque applied to the crankshaft and the torque applied to the hollow shaft to convert the torque into an axial force, and a torque detector that operates according to the displacement of the conversion unit. , Consisting of control means for controlling the electric motor according to the output of this torque detector,
According to the difference between the torque applied to the crankshaft and the torque applied to the hollow shaft under the control of the control means, the electric motor is driven or stopped to assist the traveling by the electric motor. Is a bicycle equipped with an auxiliary power unit in which the torque detector according to claim 1 is used, and the actuating body of the torque detector is operated by the converting means, and the invention according to claim 3 is also provided. According to a second aspect of the present invention, there is provided a bicycle with an auxiliary power unit, in which the torque detector according to the second aspect of the invention is arranged on the body of the bicycle such that the operating body of the torque detector is in the horizontal direction.

According to the first aspect of the present invention having the above-mentioned structure, the strain gauge is directly transmitted to the flexure element by transmitting the motion of the actuation element operated by the detected torque through the elastic body. Since the above-mentioned operation is not applied to the flexure element, the flexure element does not undergo abrupt bending, that is, bending force, and therefore, the metal fatigue and the peeling of the strain gauge can be prevented. In addition to the effect of the invention of claim 1, the invention of claim 2 has a structure in which a strain gauge is used for the torque detector. This does not prevent accurate power assistance from being lost due to wear, and has the effect that power can always be accurately assisted from the auxiliary power unit. According to the invention of claim 3, in addition to the effect of the invention of claim 2, even if the body of the running bicycle vibrates suddenly, this vibration causes the actuating body to apply a bending force to the flexure element. Since it does not act in the direction in which the torque detector moves, it is possible to prevent the torque detector from malfunctioning due to such a sudden vibration, resulting in malfunctioning of the auxiliary power unit.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the invention described in each claim will be described with reference to FIGS. As shown in the figure, a bicycle with an auxiliary power unit (hereinafter simply referred to as a bicycle) A includes a bicycle main body (hereinafter simply referred to as a vehicle body) B and an auxiliary power unit (hereinafter simply referred to as a power unit) C attached to the vehicle body B. It is configured. The vehicle body B is composed of a general bicycle, that is, a general-purpose bicycle that is generally commercially available, and includes a standing pipe 2 and a lower pipe 3 having one end fixed to a hanger lug 1, and fixed to the other end of the lower pipe 3. A frame 6 comprising an upper pipe 5 having one end fixed to the head pipe 4 and the other end fixed to a lower portion of the standing pipe 2; a chain stay 7 having one end fixed to the hanger lug 1; A front fork 8 attached to the head pipe 4, a handle 9 attached to the upper end of the front fork 8, a front wheel 10 attached to a lower end of the front fork 8, and one end fixed to the upper part of the standing pipe 2. The other end of the chain stay 7 is fixed to the other end of the chain stay 7 via a rear pawl (not shown), a back fork 11, the rear wheel 12 attached to the other end of the chain stay 7, Saddle 13 mounted above the seat tube 2, and a receiving platform 14 or the like provided in the upper portion of the rear wheel 12. The front wheel 10 and a part of the rear wheel 12 are covered by covers 10a and 12a, respectively. Further, as shown in FIG. 2, the hanger lug 1 is rotatably provided with a crank shaft 80, which will be described later.
A left crank 81 and a right crank 82 provided with pedals 81a and 82a, respectively, are attached to both ends of 0. In addition, a battery case 15 is provided on the cargo receiving base 14.
a is attached to this battery case 15a
A battery 15 is removably housed inside. Further, a control box 16a, in which a control means 16 including a control circuit including a microcomputer is housed, is attached to the vertical pipe 2. The battery 15 and the control means 16 are connected by a lead 17a, and the control means 16 and a motor 40 described later are connected by a lead 17b. Further, a chain 19 is mounted on a sprocket 18 for transmitting the rotational force during traveling and a sprocket (not shown) of the rear wheel 12.

The control box 16a is provided with a drive switch (not shown) for electrically connecting the electric motor 40, the control means 16 and the battery 15.

Next, the structure of the power unit C and how to attach the power unit C to the vehicle body B will be described.

First, the structure of the power unit C will be described with reference to FIGS. 2 and 3. As shown in the figure, the power unit C includes an electric motor 40 attached to the case 30, and a power transmission means 50 arranged in the case 30 for transmitting the rotational force, that is, the torque of the electric motor 40. The case 30 includes a case body 31 and a case lid 32. The case body 31 has a mounting portion 31a for mounting the electric motor 40, a first bearing mounting portion 31b, and a through hole 31 in the central portion.
Second bearing mounting portions 31d each having a c are formed, and the case lid 32 has a bearing mounting portion 3 corresponding to the first bearing mounting portion 31b and the through hole 31c.
2a and a through hole 32b are formed. The case main body 31 and the case lid 32 are integrally coupled with a plurality of mounting screws 33 (only one is shown in FIG. 2) in a state where the power transmission means 50 and the like are housed.

Next, the power transmission means 50 is the gear 4 attached to the tip of the output shaft 41 of the electric motor 40.
2, a large-diameter gear 51 meshed with the gear 51, a small-diameter gear 52 provided coaxially with the gear 51, and a large-diameter gear 53a rotatably mounted on the fixed shaft 53c and meshing with the gear 52.
And a bevel gear 53b integral with the bevel gear 53a, a bevel gear 54 meshing with the bevel gear 53b, and a gear 55 attached to the same shaft 54a as the shaft of the bevel gear 54. A drive gear 56 meshes with the gear 55. Then, the bevel gear 54 and the gear 5
Bearings 54c and 54d made of ball bearings are attached to both ends of the shaft 54a to which 5 and 5 are attached,
The bearings 54c and 54d are the first bearing mounting portion 31 provided on the case body 31 and the case lid 32, respectively.
b, 32a. Also, the gear 55
Is attached to the shaft 54a via a one-way clutch 54b. This one-way clutch 54b drives the drive gear 56 so that the bicycle normally travels, that is, travels in the forward direction by the rotational force or torque of the electric motor 40.
The gear 55 is rotated so as to be transmitted to, but functions to idle in the opposite direction. In other words, the one-way clutch 54b is used by the pedal 81 during the manual running described later.
When the cranks 81 and 82 to which the motors a and 82a are attached rotate in the traveling direction, they function so as to idle.

A shaft hole 56a is formed in the center of the drive gear 56, and a concavo-convex strip 56 which is generally called involute serration is formed in the shaft hole 56a.
c is formed. Further, on the side surface of the gear 56 on the side of the case lid 32, a plurality of (three in the embodiment are provided concentrically arranged on the outer periphery of the shaft hole 56a as shown in FIG.
Only one projection 57 is formed in FIG. 3, and the projection 57 is formed upward as shown in FIG. 4 along the arrow direction shown in FIG. 4, that is, the direction in which the drive gear 56 rotates during traveling. An inclined surface 57a that gradually rises is formed. Further, as shown in FIG. 3, on the side surface of the drive gear 56 on the case lid 32 side, a plurality of (three in the embodiment) are arranged between the adjacent protrusions 57 and concentrically with the shaft hole 56a. There are two, only two are shown in FIG. 3)
An L-shaped regulating member 58 for regulating one end side of a drive spring 60, which will be described later, is formed.

Next, the hollow shaft 70 which is fitted in the shaft hole 56a formed in the drive gear 56 and which transmits the power of the electric motor 40 transmitted through the power transmission means 50 to the sprocket 18 will be described. . The hollow shaft 70 has a through hole 71 therein and has the shaft hole 56a at one end side.
An uneven strip 72 is formed which engages with the uneven strip 56c formed on the shaft 56a.
By the engagement of c and 72, the rotation is prevented in the circumferential direction, and the drive gear 56 is rotated integrally. Further, an uneven ridge 73 is formed on the outer periphery of the other end, and the uneven ridge 73 is formed so as to match the uneven ridge 18b formed on the mounting member 18a to which the sprocket 18 is mounted. Further, the hollow shaft 70 has a ball bearing 7 in the vicinity where the concave-convex strip 72 formed on the one end side is formed.
7 is press-fitted into the inner ring of the hollow shaft 7.
Reference numeral 0 denotes a case in which the ball bearing 77 is attached to the case body 31 by penetrating a through hole 31c provided in the case body 31 and press-fitting an outer ring of the ball bearing 77 into the second bearing attachment portion 31d provided in the case body 31. It has become.

Next, the crankshaft 80 which is fitted through the through hole 71 of the hollow shaft 70 will be described. A mounting portion 83 including a fitting portion 83a having an outer periphery formed in a prism shape and a screw portion 83b protruding from the fitting portion 83a is provided on one end side of the crankshaft 80, and the other end side is similarly provided. Mounting portions 84 each including a fitting portion 84a whose outer periphery is formed in a prismatic shape and a screw portion 84b protruding from the fitting portion 84a are formed. The attachment portions 83 and 84 are formed in shapes and dimensions that match the fitting portions 81b and 82b of the left crank 81 and the right crank 82 of the general bicycle.

A unidirectional clutch 85 is attached to the crankshaft 80 at a position close to the drive gear 56 attached to the hollow shaft 70. The unidirectional clutch 85 is used to connect the crankshaft 80 to the crankshaft 80. Has a drive plate 90 attached. The one-way clutch 85 is provided with pedals 81a, 82 when the crankshaft 80 is manually driven as described later.
When the a is rotated in the traveling direction by the attached cranks 81, 82, the drive plate 90 is rotated,
On the contrary, when the crankshaft 80 rotates, it functions to idle. Further, on the case lid 32 side of the drive plate 90, a circular flange portion 91 is formed so as to form a space between the drive plate 90 and the side surface of the drive gear 56, and the circular flange portion 91 is formed. Then, on the surface of the flange portion 91 on the drive gear 56 side, as shown in FIG. 3, a compression portion 92 for contacting and compressing the other end side of the drive spring 60 is formed. The drive spring 60 is housed between the L-shaped regulating member 58 and the compression section 92.

The magnitude of the urging force of the drive spring 60 is compressed when the rotational force applied to the drive plate 90 via the crankshaft 80 and the one-way clutch 85 during a manual run exceeds a predetermined value. The size is set to start. That is, a large load is applied to the rear wheel 12 while the vehicle is running, and the rotational force generated by the pedals 81a and 82a stepping against the large load is applied to the crankshaft 80 via the cranks 81 and 82.
In addition, the drive plate 90 rotating together with the crankshaft 80 gradually sets the size of the drive spring 60 so that the drive plate 60 rotates ahead of the drive gear 56 and relatively moves. That is, when the vehicle travels manually, the magnitude is set such that relative rotation with the drive gear 56 occurs when the rotational force of the drive plate 90 that rotates together with the one-way clutch 85 along with the rotation of the crankshaft 80 exceeds a predetermined value. It has been done.

Therefore, when the rotational force applied to the crankshaft 80 does not exceed a predetermined value, the driving plate 90 is maintained in a state where the driving plate 90 is hardly compressed.
The rotation of the drive gear 56 is synchronized with the drive gear 56 via the zero.

The flange 91 of the drive plate 90
As shown in FIGS. 2 and 4, three through holes 93 (only one is shown in FIG. 2) are formed in a portion corresponding to the protrusion 57 formed on the side surface of the drive gear 56.

An offset plate 95 is attached to the flange portion 91 so as to be able to approach and separate from the flange portion 91. The displacement plate 95 is integrally mounted in correspondence with each of the through holes 93, and the slide shaft 9 having a flange portion 96a at the tip thereof is formed.
6 is provided, and while the slide shaft 96 is passed through the through hole 93, the deviation plate 95 is always provided between the inner surface of the flange portion 91, that is, the surface facing the drive gear 56 and the flange portion 96a. The deflection plate 95 is attached to the flange portion 91 so as to be contactable and separable via a coil spring 97 that urges the flange portion 91 in a pressure contacting direction.

The drive plate 90 and the eccentric plate 9
5 and 5 constitute a conversion means for converting the rotational force of the crankshaft 80, that is, the torque into a force in the axial direction.

Here, the principle of converting torque into axial force will be described. First, when a torque in the traveling direction, that is, torque is applied to the crankshaft 80 by the cranks 81 and 82 of the pedals 81a and 82a, this torque is applied to the one-way clutch 85 attached to the crankshaft 80.
Is transmitted to the drive plate 90 via the drive plate 90 to rotate.
When the drive plate 90 rotates, the drive plate 90 rotates with this rotation.
The torque of the drive plate 90 is transmitted to the drive gear 56 via the drive spring 60 arranged between the compression portion 92 formed in the above and the regulating member 58 of the drive gear 56, and this torque is transmitted to the drive gear 56. The bicycle A travels by being transmitted to the hollow shaft 70 via the sprocket 18 and the chain 19 and driving the rear wheel 12 via the sprocket 18 and the chain 19.

When the vehicle is traveling uphill or the like during traveling, the pedals 81a,
You have to step hard on 2a. The strong depression of the pedals 81a, 82a means that the drive plate 9 attached to the crankshaft 80 rotated by the pedals 81a, 82a via the one-way clutch 85.
Relative movement will occur between 0 and the drive gear 56 that rotates integrally with the hollow shaft 70. In other words, when the hollow shaft 70 is heavily loaded and the pedals 81a and 82a are strongly depressed, the drive spring 60 provided between the drive plate 90 and the drive gear 56 is compressed, and the drive plate 9 is compressed.
0 will rotate ahead of the drive gear 56. As a result, the tip end of the slide shaft 96 of the deflection plate 95 provided so as to be able to come into contact with and separate from the drive plate 90 moves upward along the inclined surface 57a of the projection 57 provided on the drive gear 56,
With this movement, the coil spring 97 is compressed, and the displacement plate 95 moves in a direction away from the drive gear 56, that is, in the axial direction of the crankshaft 80. As a result, the torque of the crankshaft 80 is converted into an axial force.

When the vehicle changes from traveling on an uphill to traveling on a flat surface, it returns to a predetermined state due to the restoring force of the driving spring 60, so that the relative movement between the driving plate 90 and the driving gear 56 is lost, and The shaft 96 moves downward from the inclined surface 57a of the projection 57, and the deflection plate 95 is held in contact with the driving plate 90.

Next, the torque detector 100 for detecting the torque of the crankshaft 80, that is, the detected torque according to the deviation of the deviation plate 95 which constitutes a part of the converting means.
Will be described with reference to FIGS. As shown in FIG. 5, the torque detector 100 includes a case main body 101 as a case including a lower case 110 and an upper case 120 attached to the lower case 110, and the case main body 101.
It is composed of a strain gauge 130 disposed inside, an operating body 140 that receives the acting force of the torque to be detected, a coil spring 150 as an elastic body that transmits the acting force received by the operating body 140 to the detecting means, and the like. .

The lower case 110 is provided with a recessed board arranging portion 112a for arranging a printed wiring board 112 surrounded by an outer peripheral wall 111 provided on the outer peripheral portion of the lower case 110, and the outer peripheral wall 111 has a concave portion. Is provided with a plurality of mounting through holes 113 (only two are shown in FIG. 5). In the drawing of the through hole 113, an annular positioning portion 114 is formed on the outer periphery of the upper opening. The lower case 110 has lead wires 135a to 135a.
A drawing hole (not shown) for drawing 5d is formed.

Next, the upper case 120 has a bottom wall 1
21 is formed in the shape of a box with a bottom having an outer peripheral wall 122 formed on the outer periphery thereof.
A fitting wall 124 is formed on the outer periphery of the flange portion 123 so as to fit on the outer periphery of the outer peripheral wall 111 of the lower case 110. A cylindrical portion 125 is formed on the bottom wall 121, and a part of the cylindrical portion 125 is formed so as to project inside and outside the bottom wall 121, respectively. A guide hole 126 is formed in the cylindrical portion 125 from the outer end to the substantially middle portion,
A guide hole 126 is provided in a portion from the intermediate portion to the inner end.
A larger diameter hole 127 is formed. This large hole 1
27 is a hole 1 when the coil spring 150 expands and contracts.
The diameter is made large so as not to interfere with the peripheral wall of 27.

Further, the flange portion 123 is formed with a fitting hole 128 for fitting with the positioning portion 114 provided on the outer peripheral wall 111 of the lower case 110.

Next, the detecting means 130 is formed by sticking four resistors R1 to R4 each made of a thin film on the surface of the strain element 131 made of, for example, aluminum or the like through an insulating film or by a so-called semiconductor technique. In addition to being provided, these four resistors R1 to R4 are connected by a printed wiring conductor so as to form a bridge W as shown in FIG. The connection point between the resistors R1 and R3 of the bridge W and the resistor R
4 and R2 are connected to lead wires 132a and 132b.
Is connected to the power source via the resistors R1 and R4, and the resistors R2 and R3 are connected at the output end, and the output from this output end, that is, the detected torque. Is sent to the amplifier 136 via the lead wires 133a and 133b, and the amplified output from the amplifier 136 is sent to the control means 16 and the control means is responsive to the output. 16 controls the electric motor 40.

The lead wires 132a, 132b and 133a, 133b are lead wires 135a, 135d and 135 drawn out from the lower case 110.
b, 135c is electrically connected.

The free end 131a of the flexure element 131 is also provided.
Is located below the inner end of the cylindrical portion 125 and extends so as to correspond to the guide hole 126, and a pin 134 having an axis coincident with the axis of the guide hole 126 is provided at this end. The pin 134 is provided with an annular flange 134a for receiving the other end of the coil spring 150.

Next, the actuating member 140 includes a shaft portion 141 guided by the guide hole 126 and slidably fitted in the axial direction, and a large-diameter stopper portion 142 formed at one end portion of the shaft portion 141. It is configured. In addition, a concave portion 143 is formed in the stopper portion 142, and the deflection plate 95 is formed in the concave portion 143.
A spherical body 144 for reducing friction by directly contacting the end face of 42 is housed. The coil spring 1 is attached to the tip of the actuating body 140.
A step 145 is formed to receive the end of 50. Then, the stepped portion 145 and the annular flange 134a of the pin 134 are formed.
Between the coil spring 150 and the coil spring 150, the coil spring 150 is compressed and disposed in a state in which it is compressed by a predetermined amount, that is, a state in which a predetermined bending force is applied to the flexure element 131.

The assembly of the torque detector 100 is performed by connecting the lead wires 132a, 13 from the strain gauge 130.
2b, 133a, 133b are connected to a printed wiring board 112, and the printed wiring board 112 is connected to the board placement portion 11
2a, and the fixed end of the flexure element 131 is sandwiched between the end surface of the outer peripheral wall 111 of the lower case 110 and the flange portion 123 of the upper case 120.
120 is integrally coupled by a coupling screw (not shown), and then the actuating body 140 is attached to the guide hole 126 together with the coil spring 150 from the outside.

Then, the assembled torque detector 10
No. 0 is attached to the case main body 31 of the power unit C through a through hole 113 by a mounting screw (not shown). When the power unit C is attached to the vehicle body B, the actuation body 140 of the torque detector 100 is horizontally supported in the guide hole 126. Since the operating body 140 is thus supported in the horizontal direction, the front wheels 10 or the rear wheels 12 fall into the uneven portion of the road surface or the like during traveling, and the vehicle body is subjected to a sudden vertical vibration, that is, shocking vibration. However, due to this vibration, the operating body 140 does not move in the direction in which the bending force is applied to the flexure element 131. Therefore, even if the vehicle body B receives a shocking vibration, the torque detector 100 does not malfunction due to the shocking vibration, and the malfunction of the power unit C can be prevented by this malfunction.

The operation of the torque detector 100 constructed as above will be described. The torque detector 100 operates on the same principle as a torque detector using a conventionally well-known strain gauge. In other words, the detected torque, that is, the torque of the crankshaft 80 converted into the axial force by the drive plate 90 and the displacement plate 95 forming the conversion means is actuated by the displacement plate 95.
40, and by this action the bending force is transmitted or imparted to or released from the strain element 131 by the actuating element 140 in the axial direction, thereby changing the resistance value of the resistors R1 to R4. Bridge W due to change in value
The electrical output from is taken out.

In this embodiment, the flexure element 131
The reference value is the output from the bridge W when the maximum bending force is applied to the motor, and the controller 16 controls the electric motor according to the electrical output from the bridge W that gradually changes from the maximum bending force. 40 is configured to be controlled. Specifically, pedal 8 while driving manually.
In a state in which the stepping forces of 1a and 82a do not exceed a predetermined value, that is, in a state where the drive gear 56 and the drive plate 90 do not move relative to each other, the displacement plate 95 does not move and the actuating body 140 and the coil spring 150 are not moved. Through strain body 1
The maximum bending force is applied to 31, and the electric output output from the bridge W in this state is set as a reference value. At this reference value, the electric motor 40 is stopped so that the control means 16
Is controlled by the Further, the pedaling force of the pedals 81a and 82a becomes large as in the case of traveling uphill, and when the pedaling force exceeds a predetermined value, the drive gear 56 and the drive plate 90 move relative to each other and the displacement plate 95 Move, actuating body 140, coil spring 15
The bending force of the flexure element 131 applied via 0 decreases, and the flexure element 131 restores as the bending force decreases,
As a result, the resistance values of the resistors R1 to R4 of the bridge W change, an electrical output corresponding to this change is output from the bridge W, and the control means 16 controls the electric motor 40 according to this output. It is supposed to do. The output of the bridge W is amplified by the amplifier 136 and sent to the control means 16.

The actuating member 140 is the strain generating member 131.
Is not directly pressed, but is pressed via the coil spring 150 that is an elastic body, so the strain-generating body 131 is not suddenly or instantaneously bent, and metal fatigue is less likely to occur. It is possible to prevent breakage and the like due to it, and also to prevent the resistors R1 to R4 from being separated from the flexure element 131.

Next, the rear wheel 1 of the driving force of the electric motor 40
2 will be described.

If the pedaling force of the pedals 81a, 82a becomes large and exceeds a predetermined value as described above when traveling uphill or the like by manpower traveling, the drive plate 90 rotates ahead of the drive gear 56. Relative movement occurs between the two, and as a result, the tip end of the slide shaft 96 of the displacement plate 95 moves upward on the inclined surface 57a of the projection 57 provided on the drive gear 56, and the displacement plate 95 separates from the drive gear 56. Move in the direction you want to. As a result, the maximum bending force applied to the flexure element 131 via the operating body 140 and the coil spring 150 is reduced, and the flexure element 131 is restored. With this restoration, the resistance values of the resistors R1 to R4 of the bridge W are restored. Is changed, and an electric output corresponding to the change is sent to the control means 16 via the amplifier 136. According to the magnitude of the electric output, the electric motor 40 is controlled by the control means 16 to drive or rotate. I do.

When the electric motor 40 rotates, it is transmitted from the gear 42 provided on the output shaft 41 to the drive gear 56 via the power transmission means 50, and is transmitted to the hollow shaft 70 via the drive gear 56. Rear wheel 12 through sprocket 18 and chain 19 attached to hollow shaft 70
Is transmitted to. That is, the pedals 81a, 82a
When the vehicle is stepped on, the torque of the electric motor 40 is added to or assisted by the torque generated by the human power transmitted to the crankshaft 80, so that the bicycle runs.

Next, a method of assembling the power unit C will be described. A one-way clutch 85 to which a driving plate 90 is attached in advance is prepared with the crankshaft 80 attached.

The output shaft 41 is attached to the case body 31.
A motor 40 with a gear 42 is attached to
The gears 51 to 55 constituting the power transmission means 50 are disposed at predetermined positions on the case main body 31, and the torque detector 100 is mounted by the mounting screws (not shown) as described above. Further, the hollow shaft 70 into which the ball bearing 77 is press-fitted in advance is mounted on the case main body 31 by press-fitting the ball bearing 77 into the second bearing mounting portion 31d. Then, the concave and convex ridges 56c of the drive gear 56 are fitted to the concave and convex ridges 72 formed on the hollow shaft 70, and then the crankshaft 80 is inserted into the through holes 71 of the hollow shaft 70 via needle bearings 73a and 73b. .
At the time of this insertion, the drive spring 60 is provided with the regulating member 58 formed on the drive gear 56 and the compression portion 92 formed on the drive plate 90.
It is installed between and. And the case body 31 in this state
The power unit C is assembled by inserting the case lid 32 into the through hole 32b, inserting the crankshaft 80, and attaching the case lid 32 to the case body 31 with the screws 33.

Next, the mounting of the power unit C thus assembled on the body B of a bicycle, that is, a general-purpose bicycle will be described. The power unit C is mounted on the mounting member 16 having needle bearings 161a and 162b mounted on both ends of the hanger lug 1 of the vehicle body B.
1 and 162, respectively, and the hollow shaft 70 projecting from the side wall of the case body 31 of the assembled power unit C is mounted on the bearings 161a and 162b.
The sprocket 1 is mounted on the concave and convex strip 73 formed on the hollow shaft 70 via the mounting member 18a.
8 is attached. Next, the mounting plate is attached to the case main body 31 with an attachment screw (not shown) so as to sandwich the chain stay 7 between an attachment portion 31d formed behind the case main body 31 and an attachment plate (not shown). Thus, the power plant C is formed by the hollow shaft 70 supported by the mounting members 161 and 162 mounted on the hanger lug 1 and the mounting portion 31d of the case body 31 mounted on the chain stay 7 via the mounting plate. Attached to vehicle body B. After attaching the power unit C to the vehicle body B, the pedals 81 are attached to the attachment portions 83 and 84 of the crankshaft 80.
All the assembly is completed by attaching the left crank 81 and the right crank 82 to which a and 82a are attached.

Next, the operation of the bicycle with an auxiliary power unit configured as described above will be described. First, a drive switch (not shown) provided on the control box 16a is closed.

Then, ride on a bicycle and drive. And
When the vehicle is traveling on a flat ground or a downhill, the torque or torque applied to the drive gear 56 via the crankshaft 80 does not exceed a predetermined value as described above. Are not compressed, so that the drive gear 56 and the drive plate 90 rotate in synchronism and the eccentric plate 9
Since 5 does not move but rotates together with the drive plate 90, the flexure element 131 is the actuator 140 and the drive spring 1.
The maximum bending force is applied via 50,
Resistors R1 to R4 determined by the maximum bending stress
An electric output corresponding to the value of is output from the bridge W, and the control means 16 controls the electric motor 40 to stop according to the electric output. Therefore, in this state, the power from the electric motor 40 is not output, and thus the traveling assistance is not performed, and the rotational force of the crank shaft 80 applied through the crank shafts 81 and 82 by depressing the pedals 81a and 82a is the drive gear. 56, hollow shaft 70, sprocket 1
8. The power is transmitted to the rear wheel 12 via the chain 19 and is driven manually.

Further, when traveling uphill, a large turning force is required, and as a result, the pedals 81a, 82a
Is strongly depressed, and the rotational force applied to the crankshaft 80 and the driving plate 90 increases to exceed a predetermined value. That is, the drive gear 56 includes the chain 1
9, the load applied to the hollow shaft 70 transmitting the rotational force to the sprocket 18 transmitting to the rear wheel 12 increases.
The driving plate 90 rotates faster than the rotation of the driving gear 56, so that the driving spring 60 is compressed and the driving plate 90 rotates ahead of the driving gear 56, and the slide shaft 96 of the deflection plate 95 is driven by the driving gear 56. The projection plate 57 moves upward along the inclined surface 57 a of the projection 57, and the deflection plate 95 moves away from the driving plate 90. The deflection plate 95 is the driving plate 9
When it is separated from 0, the bending force applied to the flexure element 131 is reduced and the flexure element 131 is restored or deformed. With this deformation, the resistance values of the resistors R1 to R4 change. An electrical output according to the change is output from the bridge W, and the control means 16 controls and drives the electric motor 40 according to the electrical output. When the electric motor 40 is driven, this driving force, that is, torque, is transmitted to the drive gear 56 via the power transmission means 50, and this torque is transmitted to the drive gear 56.
Through the hollow shaft 70, the sprocket 18, the chain 1
It is transmitted to the rear wheel 12 via 9. The torque from the electric motor 40 is added to the torque transmitted to the crankshaft 80 by the depression of the pedals 81a and 82a, that is, the torque due to human power. That is, when the torque due to human power exceeds a predetermined value, the power of the electric motor 40, that is, the power unit C is assisted. Therefore, even when a large torque such as an uphill is required, the vehicle can easily travel.

As described above, when the vehicle is traveling on a level ground or a downhill during human power traveling, the electric power is not assisted by the electric motor 40, that is, the power unit C, and the vehicle is traveled only by human power, and also when traveling uphill. Electric motor 40 when traveling
That is, since the power of the power plant C is assisted, the vehicle can easily travel on an uphill.

Further, the road surface on which the vehicle travels is not always flat, and for example, there are irregularities such as a gravel road or a step between the sidewalk and the roadway. When traveling on such an irregular road surface, the vehicle body moves in the vertical direction. It will be a big shock. In such a case, the actuator 140 of the torque detector 100
Is configured to slide in the vertical direction, the impact causes the actuating body 140 to slide in the vertical direction due to an action force that is unrelated to the running torque, and the bending force applied to the flexure body 131 is caused by this sliding. The electric power output from the bridge W changes, and the torque detector 100
Will malfunction. However, in the above-described embodiment, the torque detector 100 is mounted on the vehicle body B by the actuator 14
Since 0 is mounted in the horizontal direction, even if the vertical shock is applied, the actuating body is in the horizontal direction and does not slide in the vertical direction. Therefore, the torque detector 100 is It is possible to prevent malfunction.

Further, since the torque detector 100 is constructed so as to transmit the action of the detected torque to the strain-flexing body 131 not directly from the actuating body 140 but through the coil spring 150, Since the strain body 131 is not subjected to a sharp bending force, breakage due to metal fatigue or the like can be prevented, and peeling of the resistors R1 to R4 from the strain body can be prevented. In the above-described embodiment, the case where the torque detector 100 is applied to a bicycle running torque detector has been described. However, this is not limited to a bicycle running torque detector, and for example, electric power The present invention can be applied to various devices that require torque detection, such as a torque detector that detects the steering torque of the steering device.

In the above embodiment, the output of the bridge W when the maximum bending force is applied to the flexure element 131 of the torque detector 100 is used as a reference value, and when the reference value is reached, the electric motor 40 is stopped. However, conversely, the output of the bridge W in a state where there is no bending stress applied to the flexure element 131 is used as a reference value, and at this reference value, the electric motor 40
May be stopped, and the electric motor 40 may be driven by the output of the bridge W in a state in which a bending force is applied. In this case, the projection 57 is not formed on the drive gear 56, but a recess having an inclined surface that is inclined downward in the rotational direction is formed, and the drive gear 90 is movably provided. Deviation plate 9
5 is arranged at a predetermined distance from the drive plate 90, and when the torque applied to the crankshaft 80 exceeds a predetermined value and the drive plate 90 rotates ahead of the drive gear 56, the slide shaft 96 provided on the displacement plate 95. May be moved downward along the inclined surface of the recess, and the displacement plate 95 may be moved to the drive plate 90 side to operate the actuation body 140.

[0051]

According to the first aspect of the present invention having the above-described structure, the operation of the actuating body that operates by the detected torque is transmitted to the strain gauge through the elastic body by directly transmitting the action of the actuating body through the elastic body. Since the operation of is not applied to the strain-generating body, abrupt bending force is not generated, and therefore, the effect of preventing metal fatigue and peeling of the strain gauge can be obtained. In addition to the effect of the invention described in claim 1, the invention described in claim 2 has a configuration in which a strain gauge is used for the torque detector. It is possible to obtain the effect that the power cannot be accurately assisted due to wear, and the power can always be accurately assisted from the auxiliary power unit. According to the invention of claim 3, in addition to the effect of the invention of claim 2, even if shocking vibration occurs in the body of a running bicycle, the shocking vibration causes the actuation body to be a strain body. Since it does not act in the direction in which the bending force is applied, it is possible to prevent the torque detector from malfunctioning due to such shocking vibrations, resulting in malfunctioning of the auxiliary power unit. It is a thing.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment in which the torque detector of the present invention is used in a bicycle with an auxiliary power unit of the present invention.

FIG. 2 is a sectional view showing a state in which an auxiliary power unit is attached to the bicycle body according to the embodiment.

FIG. 3 is a side sectional view of a part of the auxiliary power unit according to the embodiment.

FIG. 4 is a partially enlarged view of a conversion unit in the embodiment.

FIG. 5 is a sectional view showing an embodiment of a torque detector of the present invention.

FIG. 6 is a diagram showing an electric circuit of the torque detector.

[Explanation of symbols]

 A bicycle with auxiliary power device B bicycle main body (vehicle body) 16 control means 30 case 40 electric motor 50 power transmission means 56 drive gear 57 projection 57a inclined surface 70 hollow shaft 80 crankshaft 81 left crank 82 right crank 90 drive plate (converting means) 95 Displacement plate (part of conversion means) 100 Torque detector 101 Case (housing) 110 Lower case 120 Upper case 126 Guide hole 130 Strain gauge 131 Strain element R1 to R4 Resistor 140 Actuator 150 Coil spring (elastic body) W bridge

Claims (3)

[Claims] 1. A casing having a guide hole, an actuator movably arranged in the guide hole and operated by receiving an acting force of a torque to be detected, and a thin film resistor on the surface of the flexure element. A strain gauge provided by connecting and arranging the body so as to form a bridge and fixing the fixed end with the free end facing the guide hole, and the acting force received by the operating body on the free end. A torque detector comprising: an elastic body that transmits the torque. 2. An electric motor and a plurality of gears arranged in a case, including output gears, for transmitting a rotational force of the electric motor, and a bearing, which is rotatably attached to the case and has one end side. A hollow shaft connected to the output gear and having a sprocket attached to the other end thereof and connected to the power transmission means, and a hollow shaft rotatably supported inside the hollow shaft and penetrating the hollow shaft. A crankshaft to which a crank having pedals at both ends is attached, a conversion unit that operates according to a difference between a torque applied to the crankshaft and a torque applied to the hollow shaft, and a conversion unit that converts the torque into an axial force. Of the torque detector and a control means for controlling the electric motor according to the output of the torque detector. 2. A bicycle with an auxiliary power unit that drives or stops the electric motor according to the difference between the torque applied to the rank shaft and the torque applied to the hollow shaft to assist traveling by the electric motor. A bicycle with an auxiliary power unit, comprising a torque detector, and an actuating body of the torque detector being operated by the converting means. 3. The bicycle with an auxiliary power unit according to claim 2, wherein the torque detector is arranged on the body of the bicycle such that the operating body of the torque detector is horizontal.