Electricity: measuring and testing – Magnetic – Combined
Patent
1997-04-30
2000-12-19
Show, Walter
Electricity: measuring and testing
Magnetic
Combined
32420725, 180206, G01B 730, B62M 2302, G01L 314, G01R 3300
Patent
active
061631485
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The invention relates to a sensor which is provided with a magnet and a magnetic detecting element to detect the rotation angle of a measuring object, a drive force auxiliary device using this sensor for an electric bicycle or the like, and a torque sensor zero point adjusting mechanism of the drive force auxiliary device.
BACKGROUND ART
A generally known sensor for detecting a rotation angle uses a potentiometer.
A sensor using the potentiometer is a contact type sensor, and therefore, the device suffers from a shortened life because of friction.
With the development of remarkable magnets in these years, non-contact type sensors utilizing a magnetic detecting element are being used in various ways. Since the sensor utilizing a magnet and a magnetic detecting element is a non-contact type, its life can be made long, and a potentiometer which is expensive is not needed. Therefore, the sensor can be produced inexpensively.
To detect a rotation angle by a non-contact type sensor using a magnetic detecting element, it is desired that the angle is magnetically detected by the magnetic detecting element. At this time, an air gap is secured between the magnet and the magnetic detecting element without fail, magnetic flux of a magnetic circuit is guided in a predetermined direction to configure a stable magnetic circuit. Besides, this type of sensor is demanded to prevent accuracy from being degraded due to performance of parts or an error in production, thus improving reliability.
In view of above, the present invention aims to provide a sensor which secures an air gap between the magnet and the magnetic detecting element without fail, guides magnetic flux of a magnetic circuit in a predetermined direction to configure a stable magnetic circuit, and improves reliability.
Lately, attention is being attracted by an electric bicycle provided with an electric motor for assisting human power. This type of electric bicycle is structured by mounting an electric motor and a battery power source for supplying power to the motor on an ordinary bicycle to add a predetermined motor auxiliary power depending on a human power driving force, thereby reducing a load on a human power drive force. And, the auxiliary drive force by a motor is legally limited not to exceed the human power drive force in Japan, and when a running speed does not exceed 15 Km/h, assistance by the motor is 100%, and when the running speed exceeds 15 Km/h, assistance is decreased gradually, then when the speed is 24 Km/h or more, control is made to stop the assistance by the motor. Thus, a human power assisting ratio is restricted to be variable in accordance with the running speed.
As shown in FIG. 54, such an electric bicycle 1 is basically formed of an ordinary bicycle which is provided with a front wheel 4 and a rear wheel 5 at the front and rear of its frame, and driven by leg power via the rear wheel 5. According to the Japanese Industrial Standards (JIS), the member indicated by reference numeral 2 is called a main pipe and the member indicated by reference numeral 2d is called a seat pipe, and the same designation by the JIS standards is used in this specification.
This auxiliary drive means J comprises a motor M which is disposed at right angles with the axle and in the neighborhood of the middle in the breadth direction of the vehicle body, a power transmission (not shown) which changes the rotating drive force of the motor towards a direction that the axles are rotated and also decrease the speed, and a combining mechanism (not shown) which combines the decelerated rotating drive force of the motor with an ordinary drive system of the human power drive force and separates the motor drive system from the ordinary drive system when the bicycle is driven by the human power drive force only.
The motor drive system is driven to rotate by the power transmission device with the motor M as the drive source, and the Motor M is supplied with electric power by an electric power device. Specifically, this electric power device comprise
REFERENCES:
patent: 3366909 (1968-01-01), Hini et al.
patent: 5523679 (1996-06-01), Kalb
Miyazawa Hiroshi
Nakazato Hiroshi
Shinkai Katsumi
Takada Yutaka
Tanaka Kuniaki
Seiko Epson Corporation
Show Walter
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