JPH10167162A - Electric bicycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric bicycle which accurately judges abnormalities of a torque detector for detecting a pedal load by pedal torque as well as the actual motion of an electric drive device to safely stop the electric drive device. SOLUTION: An electric current detector 12 for detecting the current of an electric motor 11 of an electric drive device 3 is provided to detect the minimum value of the current of the electric motor 11 and a difference between the maximum value and the minimum value, that is, the range of variation in the current caused by the rotation of the pedal and a computer 9 stops the electric drive device 3 when the minimum value is not less than 10A and the range of variation is not more than 5A, which can not only detect the abnormalities of the torque detector 7 but also safely stop the electric drive device 3 in response to the abnormalities of a control circuit 13 itself.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric bicycle which operates an electric driving device in response to a pedal load, and more particularly to an electric bicycle which can appropriately cope with an abnormality of a torque detector which detects the pedal load by a pedal torque. About.

[0002]

2. Description of the Related Art In recent years, various proposals have been made for electric bicycles which assist driving force by human power with an electric driving device.

In general, an electric bicycle has a torque detector for detecting a pedal load by a pedal torque, a pedal rotational speed detector for detecting a vehicle speed, an electric motor for generating a driving force, and a rotational speed of the electric motor being reduced. And a control circuit for controlling the electric drive device, wherein the control circuit is controlled within a predetermined range based on information from the torque detector and the pedal rotation speed detector. The electric driving device is controlled to assist the driving force. The above torque detector, pedal rotation speed detector, control circuit, electric drive, etc. are built around the main pipe and seat pipe of the electric bicycle body, and the entire resin cover is included, including the wiring that connects them. Covering. A power switch for operating the electric bicycle is arranged on the upper surface or side surface of a resin case provided below the saddle. In addition, a rechargeable battery is used as an electric energy source of the electric drive device.

[0004] The above-mentioned regulations concerning the assistance by the electric drive device stipulate the ratio of the assistance to the driving force by human power with respect to the vehicle speed, and 5% when the vehicle speed is 0 to 15 km / h.
From 0%, from 15 to 24 km / h, it shall be gradually reduced according to the vehicle speed, and it shall be specified that assistance will be provided at 0 km at 24 km / h.

[0005] Before riding an electric bicycle, when a power switch (generally called a main switch) is turned on, a microcomputer built in the control circuit checks the entire circuit. It becomes a state and becomes operable. When the driver steps out the pedal,
An output of the electric driving device is determined based on information of the torque detector and the pedal rotation speed detector, and the electric motor is operated. At this time, it is essential to accurately grasp the pedal torque, and convert the reaction force of the planetary gear and the torsion bar torsion into the displacement of the potentiometer,
Means for extracting as an electric signal are generally used. The microcomputer determines the duty of the PWM output for driving the motor based on the pedal torque information and the pedal rotation speed information.

The pedal torque has a torque fluctuation of 2 Hz per rotation due to its structure. That is, the pedal torque is minimized at the upper fulcrum and the lower fulcrum of the pedal, and is maximized almost right beside. When the torque detector fails, the pedal torque may be continuously maintained at a high value. In response to this, the microcomputer controls the PWM output to be maintained at a high value. This results in faster battery consumption. In order to prevent this situation, there has been proposed a method of monitoring the fluctuation of the output voltage of the torque detector and determining an abnormality.
For example, Japanese Patent Laying-Open No. 5-310177 discloses a means for limiting the output of the electric drive device when the output voltage of the torque detector is equal to or higher than a specified value and continues for a predetermined time or longer. Thereby, when the pedal torque is maintained at a high point, it is possible to determine an abnormality due to a failure of the torque detector, a bite of a foreign substance, or the like.

[0007]

In such a conventional electric bicycle, only an abnormality in the output of the torque detector is determined.
There is a problem that it is not possible to judge whether an actual output of the electric drive device is output as prescribed because it is not determined whether a microcomputer or an electric motor is abnormal.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide an electric bicycle capable of judging an abnormality of a torque detector including an abnormality of an actual output of an electric driving device and safely performing an abnormality treatment. I do.

[0009]

According to the present invention, there is provided an electric bicycle in which a motor current during operation is monitored, and an abnormality of a torque detector is determined based on a state of the motor current. .

Thus, the electric drive unit is stopped in response to not only the abnormality of the torque detector but also the abnormality of the control circuit itself.

According to a second aspect of the present invention, the minimum value of the motor current is 10 A or more, and the difference between the maximum value and the minimum value is 5
2. The electric bicycle according to claim 1, wherein when the value is within A, the torque detector is determined to be abnormal and the electric drive device is not operated.

Thus, it is possible to perform an abnormal treatment in accordance with the rules relating to the driving force assist.

[0013]

In the present invention according to the first aspect, a current detector for detecting a motor current is provided to detect a minimum value of the motor current, and a fluctuation width given by a difference between the maximum value and the minimum value. Is detected, and when the minimum value is equal to or more than a predetermined value and the fluctuation width is within a predetermined value, it is determined that there is an abnormality and the electric driving device is stopped.

The above control can be realized by a microcomputer, and the wheel size required for calculation related to driving assistance,
Data such as the reduction ratio and the characteristics of the electric motor may be read from a database previously written in a built-in ROM, for example.

In the present invention according to claim 2, when the minimum value of the motor current is 10 A or more and the fluctuation range is within 5 A, it is determined that the motor is abnormal.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the electric bicycle according to the present invention will be described below with reference to the drawings. FIG. 1 is an external view showing the configuration of the present embodiment. In the figure, the body frame has the same basic structure as a general bicycle, 1 is a main pipe which integrally connects a front wheel, a rear wheel and a saddle, and a plurality of pipes are integrally formed at a lower end of a saddle pipe 2 at the center of the vehicle body. The electric drive device 3 is incorporated in the lower center of the vehicle body frame on the outer side, and the power switch 4 is incorporated between the rear wheel 5 and the battery box 6.

FIG. 2 is a block diagram showing a configuration of a control circuit for controlling the electric driving device in the present embodiment. In the figure, reference numeral 7 denotes a torque detector for detecting a pedal load based on a pedal torque, 8 denotes a pedal rotational speed detector for detecting a pedal rotational speed, 9 denotes a microcomputer, 10 denotes a wheel size, characteristics of the electric motor 11, and a reduction ratio. A current detector for detecting the current of the electric motor 11; The torque detector 7 detects the pedal torque and outputs a DC voltage of 0.3 to 5.0 V to the microcomputer 9. The pedal rotation speed detector 8 detects the pedal rotation speed and inputs the detected signal to the microcomputer 9 by a pulse signal. The microcomputer 9 inputs the information of the pedal torque from the torque detector 7 and the information of the pedal rotation speed from the pedal rotation speed detector 8 so that the information that the driver is riding the electric bicycle and the microcomputer 9 And information for calculating the vehicle speed of the vehicle. Further, the reduction ratio, the wheel size, and the electric motor 1 of the electric driving device 3 are obtained from the database 10.
The information such as the characteristic of No. 1 is obtained, the PWM output to the electric motor 11 is determined based on the information, and the electric motor 11 is operated. At this time, the current detector 12 constantly monitors that the motor current of the motor 11 fluctuates in synchronization with the fluctuation of the pedal torque.

FIG. 3A is a waveform diagram showing the torque voltage and the motor current in the normal state, and FIG. 3B is a waveform diagram showing the torque voltage and the motor current in the abnormal state.
As shown in the figure, the torque voltage output from the torque detector 7 periodically fluctuates at 2 Hz per one revolution of the pedal, and the fluctuation width of the motor current is linked to the fluctuation width of the torque voltage. At this time, when an abnormality occurs in the torque detector 7, FIG.
As shown in (b), the fluctuation width is smaller than in the normal state, and as a result, the fluctuation width of the motor current is also smaller.
As a result, the fluctuation of the output torque of the electric motor 11 is reduced, and the motor 11 is assisted more than necessary. Therefore, an abnormality is determined by monitoring the fluctuation of the electric motor current, and the microcomputer 9 stops the electric driving device 3 to perform an abnormality treatment. Since this abnormal action is executed in accordance with the fluctuation range of the motor current, the torque detector 7
In addition to the abnormality described above, the electric drive device 3 is stopped when, for example, an abnormality occurs in the control circuit 13 itself.

In this embodiment, if the minimum value of the motor current is 10 A or more and the fluctuation range is 5 A or less based on various experiments on the above-mentioned rules relating to the driving force assist, the torque detector 7 or When it is determined that the control circuit 13 has an abnormality, the microcomputer 9 stops the electric driving device 3 as an abnormality treatment. The reason for setting the current value to 10 A or more is that, when the motor current is small, depending on the vehicle speed, the fluctuation range may be normal even within 5 A, and it is difficult to make a judgment. It is expected that there will be no major problems.

As described above, according to the present embodiment, the electric current is monitored by providing the electric current detector 12 for detecting the electric current of the electric motor 3 so that the electric current becomes 1
When the electric drive device 3 is stopped when it is 0 A or more and the fluctuation width that fluctuates in conjunction with the rotation of the pedal is within 5 A, not only the failure of the torque detector 7 but also the control circuit The electric drive device 3 can be safely stopped in an appropriate manner in response to the failure of the motor 13 itself.

[0021]

As is clear from the above description, the present invention monitors the motor current by providing a current detector for detecting the motor current of the electric drive device, and when the motor current is equal to or more than a predetermined value. In addition, by stopping the electric drive device when the fluctuation range that fluctuates in association with the rotation of the pedal is within a predetermined value, not only the abnormality of the torque detector but also the abnormality of the control circuit of the electric drive device Accordingly, the electric driving device is stopped to prevent excessive assistance, and the electric driving device can be appropriately operated.

Further, according to the abnormality detection method of the present invention, the motor current monitor for overload detection, which is generally built in the control circuit of the electric drive device, can be used for the current detector, and the cost does not increase. A safe electric bicycle can be provided.

[Brief description of the drawings]

FIG. 1 is an external view showing a configuration of an electric bicycle of the present invention.

FIG. 2 is a block diagram showing a configuration of a control circuit in the electric bicycle of the present invention.

FIG. 3 is a waveform chart showing torque voltage and electric motor current in the electric bicycle of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main pipe 2 Saddle pipe 3 Electric drive 4 Power switch 5 Rear wheel 6 Battery box 7 Torque detector 8 Pedal rotation speed detector 9 Microcomputer 10 Database 11 Motor 12 Current detector 13 Control circuit

Claims (2)

[Claims] 1. An electric bicycle, comprising: a pedal drive device driven by human power; and an electric drive device for assisting the driving force of the pedal drive device, detects an abnormality in a torque detector that detects a pedal load by a pedal torque. An electric bicycle, wherein the determination is made based on a motor current of the electric driving device. 2. When the minimum value of the motor current is 10 A or more and the difference between the maximum value and the minimum value is 5 A or less, it is determined that the torque detector is abnormal and the electric drive device is not operated. The electric bicycle according to claim 1.