Motor vehicles – Special wheel base – Having only two wheels
Reexamination Certificate
1998-10-20
2001-01-16
Johnson, Brian L. (Department: 3618)
Motor vehicles
Special wheel base
Having only two wheels
C180S206500, C280S259000, C073S862333
Reexamination Certificate
active
06173801
ABSTRACT:
TECHNICAL FIELD
The present invention relates to manpowered vehicles such as bicycles that are provided with auxiliary power apparatuses for supplementing manpower in accordance with the load on the manpower.
BACKGROUND ART
A known auxiliary powered bicycle has a drive wheel to which a motor is connected. When the bicycle is driven by manpower, the motor is driven in accordance with the load applied to the pedal. This produces auxiliary power that supplements the manpower. Thus, the bicycle can be driven with a low degree of manpower.
Japanese Unexamined Patent Publication No. 4-100790 describes an example of how to measure the drive force applied by man. A torsion bar is used as a pedal crank axle. A detector such as a potentiometer or a strain gauge is arranged on the torsion bar to detect the twisted amount of the torsion bar and thus measure the applied torque.
However, the potentiometer or the strain gauge is arranged on a rotated axle. Thus, signals representing the detected value must be output using a slip ring or a brush. As a result, there is a tendency for noise to be included in the signals due to friction and abrasion. This makes it difficult to detect torque accurately.
In addition, the employment of a slip ring or a brush produces aural noise caused by friction as the bicycle moves. Such noise may make the rider feel uncomfortable.
Furthermore, the slip ring and the brush must be replaced when abrasion occurrs. Such replacement is burdensome.
Accordingly, it is an objective of the present invention to provide an auxiliary powered manpowered vehicle having a torque detector that detects the torque applied to a rotated crank axle in a non-contact manner in order to prevent the production of noise caused by friction or abrasion and detect torque accurately.
It is a another objective of the present invention to provide an auxiliary powered manpowered vehicle that prevents the production of aural noise due to friction when the bicycle travels and thus does not make the rider feel uncomfortable.
It is also an objective of the present invention to provide an auxiliary powered manpowered vehicle that prevents abrasion between parts and thus eliminates the necessity for the replacement of such parts.
It is a further objective of the present invention to provide an auxiliary powered manpowered vehicle that detects a load acting along the rotating direction of a crank axle and a drive gear within the same plane and thus uses restricted space in an effective manner.
DISCLOSURE OF THE INVENTION
The auxiliary powered manpowered vehicle according to the present invention is a man powered vehicle, which includes an auxiliary power apparatus having a power source for supplementing the driving of the manpowered vehicle. The manpowered vehicle includes a main body, a rotated body supported by the main body and driven by manpower, a rotary coil arranged coaxially with the rotated body, a variable impedance device electrically connected to the rotary coil and having impedance varied in accordance with the load applied to the rotated body, a fixed coil fixed to the main body such that the fixed coil is concentric with and spaced by a predetermined distance from the rotary coil and is electromagnetically coupled with the rotary coil, a detecting circuit connected with the fixed coil and detecting changes in electric current or voltage of the fixed coil caused by the rotary coil in accordance with the impedance varied by the variable impedance device, and a controller for controlling the power source based on the output value of the detecting circuit.
In such structure, the application of load to the rotated body varies the impedance of the variable impedance device, which is arranged in the rotary coil. The varied impedance is transmitted to the fixed coil by electromagnetic coupling between the rotary coil and the fixed coil. This varies the electric current or the voltage of the fixed coil. The change in the electric current or voltage is detected by a detecting device. The power source of the auxiliary power device is driven in accordance with the detected value.
In the present invention, the load applied to the rotated body varies the impedance of the variable impedance device, which rotates integrally with the rotated body. The variation is transmitted to the detecting circuit by way of the electromagnetic coupling between the rotary coil and the fixed coil. Therefore, a slip ring is not necessary for extracting torque signals and the production of noise resulting from friction or abrasion is prevented. Accordingly, the torque applied to the rotated body is measured accurately. Furthermore, noise produced by friction during the movement of the vehicle is eliminated. Thus, the operator does not feel discomfort that would result from such friction noise. Additionally, there is no abrasion of parts. Therefore, replacement of parts is not necessary. This enhances reliability and durability.
The manpowered vehicle according to the present invention further provides a support plate movable along the axial direction of the rotated body with the fixed coil being arranged on the support plate, a spacer arranged between the support plate and the rotated body to maintain the distance between the two coils, and an urging member for affecting the support plate such that the spacer maintains the distance. With this structure, the distance between the fixed coil and the rotary coil is maintained by the spacer. Accordingly, the distance between the fixed coil and the rotary coil is maintained even when swaying or vibrating occurs. This improves the reliability and accuracy of the measured torque signal.
It is preferable that the spacer includes a ball bearing having a pair of races, and a plurality of balls held between the races. With this structure, the fixed coil and the rotary coil are rotated relatively by the ball bearing.
The expansion and contraction of the urging member and the existence of the spacer maintains a constant distance between the fixed coil and the rotary coil even if the length of the axle projecting from the main body differs due to application to a vehicle having dimensional differences resulting from production or application to a different type of vehicle. Thus, the two coils may be designed to have a constant distance therebetween for each vehicle type. In addition, fine adjustment of the distance between the coils is not necessary.
The arrangement of the ball bearing between the support plate, on which the fixed coil is located, and the rotated body, on which the rotary coil is located, maintains smooth rotation even if the urging member urges the support plate toward the rotated body.
It is preferable that the auxiliary power apparatus includes a power source circuit for supplying electric power in a cyclic manner to the fixed coil. In this case, the cyclic electric power supplied to the fixed coil by the power source circuit and electromagnetic induction between the fixed coil and the rotary coil generates induced electromotive force in the rotary coil. Furthermore, mutual induction affected by impedance, which is varied by the variable impedance device, acts on the fixed coil.
In an embodiment according to the present invention, the rotated body includes a crank axle pivotally supported by the main body and a drive gear rotatably coupled to the periphery of the crank axle. A crank arm has a basal end fixed to the crank axle and a distal end on which a pedal is arranged to rotate the crank arm integrally with the crank axle. The drive gear is connected to a manpowered drive wheel. The crank axle and the drive gear are connected by an elastic body to rotate integrally with each other. With this structure, rotation of the pedal is transmitted to the drive gear by way of the elastic body, and the load acting on the drive wheel relatively displaces the positional relationship between the crank axle and the drive gear in the rotating direction against the elasticity of the elastic body.
In this case, the drive gear does not move in the axial direction of the crank axle
Aoki Hideaki
Kakutani Kazushige
Kawakami Hideo
Tomigashi Yoshio
Arent Fox Kintner & Plotkin & Kahn, PLLC
Johnson Brian L.
Lerner Avraham H.
Sanyo Electric Co,. Ltd.
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