JPH10153503A - Detecting device for pedaling force of bicycle with motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a detecting device whose constitution is simple, by which pedaling force of bycycle can be detected precisely, which is small, and whose installation space is small. SOLUTION: The detecting device is provided with a rotation driving body 16 which is installed so as to be freely rotatably and movable relatively to the axial direction of the pedal shaft 14 of a bycycle and which is connected to a driving wheel. It is provided with a stationary body 28 which is installed at the rotation driving body 16 via a bearing 26 and which is at a standstill with reference to a frame 37 at the bycycle. transmission means 22, 24 by which the pedaling force of the pedal shaft 16 is transmitted to the rotation driving body 16 and by which a force proportional to the pedaling force of the pedal shaft 14 is transmitted to the stationary body 28 as a force in a thrust direction and a stress sensor 40 to which the transmitted force is applied are installed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for detecting a treading force of a motor-equipped bicycle for driving a driving wheel of the bicycle using an electric motor.

[0002]

2. Description of the Related Art Conventionally, a bicycle with an electric motor is provided with a pedaling force detecting device for controlling a motor torque of a drive motor for reducing the pedaling force to an appropriate torque. As this pedal force detecting device, for example, there is a device that converts a rotational force of a pedal shaft into a mechanical displacement, slides a variable resistor, and uses the variable resistor as a control signal of a drive motor.

Further, according to the applicant of the present invention, the pedaling force is transmitted via a spring between a rotary drive unit integrated with a pedal and a sprocket on which a chain is hung, so that the pedaling force is expressed as an extension amount of the spring. It also proposes something that has been done. In this case, the amount of extension of this spring is
The rotational phase difference between the sprocket and the rotary driving body is temporally detected, and the time difference is multiplied by the rotational speed (vehicle speed) to obtain a motor control signal as a value indicating the pedaling force at that time.

[0004]

In each of the above-mentioned prior arts, a dedicated vehicle body, a pedal shaft and a drive transmission mechanism are required as a treading force detecting section, and the structures of the treading force detecting device and other components are complicated. It was also a factor of cost increase. In addition, in the case of the above-mentioned conventional technology in which the detection is performed by the former variable resistor, the pedaling force is converted into a displacement amount,
Since the resistance value of the variable resistor is changed, a return spring is required, and furthermore, a space corresponding to the stroke of the variable resistor is required, and there is a disadvantage that the size becomes large.
Further, in the latter conventional technique using a spring, since the pedaling force is detected as a time delay of the phase, processing such as multiplication with the vehicle speed is required, and the circuit configuration becomes complicated, and the detection is performed. The accuracy was not good either.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and provides a pedaling force detecting device for a motor-equipped bicycle which can accurately detect a pedaling force with a simple structure, and which is small and requires little installation space. The purpose is to provide.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a bicycle pedal shaft, a rotary driving member provided to be rotatable and axially movable relative to the pedal shaft, and connected to a driving wheel. A stationary body provided to the rotary driver via a bearing, and stationary with respect to the bicycle body; and transmitting the pedaling force of the pedal shaft to the rotary driver and proportional to the pedaling force of the pedal shaft to the stationary body. The present invention provides a pedaling force detecting device for a motor-equipped bicycle that includes a transmitting unit that transmits the transmitted force as a force in a thrust direction and a stress sensor to which the transmitted force is applied.

[0007] The transmitting means is an engaging surface formed on a side surface of the rotary driving body and obliquely intersecting the pedal shaft, and one end of a pedal crank fixed to the pedal shaft. A thrust direction force applied to the rotary driver by the engagement between the engagement surfaces, biasing the stationary body via the bearing, and This can be added to the sensor via the holding member.

In the pedaling force detecting device for a motor-equipped bicycle according to the present invention, the pedaling force is transmitted from the engaging portion of the pedal crank to the engaging surface of the rotary driving member.
By the action of the slope, the pedaling force of the pedal is divided into the rotational force and the thrust force of the rotary driving body, and the thrust force is applied to the stationary body via the bearing and from the stationary body via the holding member. In addition to the stress sensor, the strain of the stress sensor is electrically detected as a change in resistance value.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. As shown, the pedaling force detection device for a motor-equipped bicycle according to this embodiment has a pedal shaft 14 provided integrally with a base end portion 13 of a crank 12 of a bicycle pedal 10. A rotary drive 16 is provided which is relatively rotatable and axially movable and is connected to drive wheels (not shown). As shown in FIG. 2, a sprocket 20 on which a chain 18 for driving wheels is mounted is integrally fixed to the rotary driving body 16. Further, as shown in FIGS. 3 and 4, the rotary driving body 16 has engaging surfaces 22 formed on the side surfaces thereof and obliquely intersecting the pedal shaft 14 at an angle of about 15 ° with all sides. . As shown in FIG. 5, the engaging surface 22 faces the base end 13 of the pedal crank 12 fixed to the pedal shaft 14, and the end of the base end 13 is An engagement portion 24 that engages with the surface 22 is formed.

The rotary drive 16 is connected via a bearing 26 to a stationary body 28 which is stationary with respect to the body 37 of the bicycle. The holding member 3 is attached to the stationary body 28.
0 is fixed at one end, and the other end of the holding member 30 is fixed to one end of the sensor mounting member 32 by a bolt 34. As shown in FIG. 6, a stress sensor 40 such as a strain gauge is integrally attached to the front and back surfaces of the sensor mounting member 32, and the other end is fixed to a bicycle body 37 by a bolt 38.

As shown in FIG. 7, the control unit of the drive motor by the pedaling force detecting device according to this embodiment converts the resistance value change due to the distortion of the stress sensor 40 into a voltage value by the differential amplifier 4.
6 and the output of the differential amplifier 46 is
After that, the signal is input to a PWM circuit 50 that performs pulse width modulation (PWM) on the signal. The output of the PWM circuit 50 is connected to the gate of the FET 52. FET 52 is
It is connected in series to a drive motor 54 that assists in driving the bicycle.

In the pedaling force detecting device for a motor-equipped bicycle according to the present invention, the stepping force on the pedal 10 is transmitted from the engaging portion 24 of the pedal crank 12 to the engaging surface 22 of the rotary drive 16.
In this engagement state, the engagement surface 22 formed in a slope shape
And the engagement portion 24, the pedaling force of the pedal 10 is transmitted to the rotary driver 16 in the rotation direction, and the thrust force of the pedal shaft 14 is applied to the rotary driver 16. The force in the thrust direction presses the rotary drive 16 in the thrust direction, and the rotary drive 16
6. The holding body 30 fixed via the stationary body 28 is elastically deformed, and slightly moves in the axial direction of the pedal shaft 14. The thrust force urges one end of the sensor mounting member 32, and the stress sensor 40 of the sensor mounting member 32 is distorted with respect to the other end fixed to the vehicle body 37.
Thus, the distortion is electrically detected as a change in the resistance value.

As shown in FIG. 7, the output of the stress sensor 40 is input to a differential amplifier 46, and an output proportional to the pedaling force is output from the differential amplifier 46.
, And is converted to a signal having a pulse width proportional to the treading force, and is input to the FET 52. FET5
2, a signal in which an ON period of a pulse signal proportional to the treading force is input, and a time ratio in which a current flows through the drive motor 54 is set in proportion to the treading force. When the pedaling force is large and the load is large, more auxiliary driving force is applied to the driving wheels of the bicycle via the driving motor 54.

According to the pedaling force detecting device of this embodiment, the pedaling force of the pedal 10 is directly detected as the resistance value of the stress sensor 40, and the displacement is directly converted to a voltage value. Signal can be obtained. Moreover,
Since the current is controlled by the PWM circuit 50 when the drive motor 54 is controlled by the pedaling force, the auxiliary drive force can be accurately supplied with a simple circuit.

The pedaling force detecting device for a motor-equipped bicycle according to the present invention is not limited to the above embodiment, and the engaging member having a slope is provided on either the pedal crank side or the rotary driving body. It is sufficient that a force proportional to the pedaling force is formed and transmitted in the thrust direction of the pedal shaft. Further, the stress sensor may be a variable inductance for detecting displacement in the thrust direction of the rotary driving body or a capacitance sensor other than the strain gauge. Further, other means such as an encoder may be used.

[0016]

The pedaling force detecting device for a motor-equipped bicycle according to the present invention detects the pedaling force of the pedal as a force in a thrust direction applied to a rotary driving member provided on the pedal shaft.
With a simple configuration, accurate detection of the pedaling force is possible, and the device can be downsized.

[Brief description of the drawings]

FIG. 1 is a partial longitudinal sectional view showing a pedaling force detection device for a motor-equipped bicycle according to an embodiment of the present invention.

FIG. 2 is a side view including a pedal portion of the pedaling force detection device for the motor-equipped bicycle according to the embodiment of the present invention.

FIG. 3 is a partial side view showing an engagement portion between a pedal crank and a rotary driver of the pedaling force detection device for a motor-equipped bicycle according to one embodiment of the present invention.

FIG. 4 is a side view showing an engagement portion of a rotary driving body of the pedaling force detection device for a motor-equipped bicycle according to one embodiment of the present invention.

FIG. 5 is a side view showing a pedal crank of the pedaling force detection device for the motor-equipped bicycle according to one embodiment of the present invention.

FIG. 6 is a small view (A), a right side view (B), and a schematic view (C) showing an operation state of a stress sensor and a sensor mounting member of the pedaling force detection device for a motor-equipped bicycle according to an embodiment of the present invention.
It is.

FIG. 7 is a circuit diagram of a pedaling force detection device for a motor-equipped bicycle according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Pedal 12 Pedal crank 14 Pedal shaft 16 Rotation drive 22 Engagement surface (transmission means) 24 Engagement part (transmission means) 26 Bearing bearing 28 Stationary body 30 Holder 32 Sensor holding member 37 Vehicle body 40 Stress sensor

Claims (3)

[Claims] 1. A bicycle pedal shaft, a rotary driving body provided to be rotatable and axially movable relative to the pedal shaft and connected to driving wheels, and a bearing for the rotary driving body. A stationary body that is provided with respect to the bicycle body and that transmits the pedaling force of the pedal shaft to the rotary drive body and transmits a force proportional to the pedaling force of the pedal shaft to the stationary body as a thrust force. A stepping force detecting device for a motor-equipped bicycle, comprising a transmitting means and a stress sensor to which the transmitted force is applied. 2. The transmission means is an engagement surface formed on a side surface of the rotary driver and obliquely intersecting with the pedal shaft, and one end of a pedal crank fixed to the pedal shaft. An engaging portion that comes into contact with the engaging surface, a thrust force applied to the rotary driving body by the engagement of the engaging surface and the engaging portion urges the stationary body through the bearing, 2. The stepping force detecting device for a motor-equipped bicycle according to claim 1, wherein the device is applied to the stress sensor from the stationary body via a holding member. 3. The stress sensor is fixed to a bicycle body via a sensor mounting member.
3. The pedaling force detecting device for a motor-equipped bicycle according to claim 2, wherein the stress sensor is mounted, and a thrust force from the holding body is applied to the sensor mounting member.