Motor vehicles – Transmission mechanism – Variable speed or direction
Reexamination Certificate
1998-05-29
2001-02-13
Johnson, Brian L. (Department: 3618)
Motor vehicles
Transmission mechanism
Variable speed or direction
C180S205200
Reexamination Certificate
active
06186264
ABSTRACT:
BACKGROUND OF TIE INVENTION
The present invention relates to a motor-assisted bicycle that transmits driving force from a motor or the like so as to run with the driving force as a driving source.
Conventionally a motor-assisted bicycle of this type, as described in Japanese Unexamined Patent Publication No. 58568/1997 (B62M23/02), is designed to have a pulley provided on an output shaft of a motor, rotate the next pulley through a belt engaged on the pulley, and couple the pulley to a gear formed on an inner periphery of a rotational casing so as to transmit driving force. By provision of a one-way clutch in the pulley, the rotation by the motor driving force can be cut off, when the rotation speed of a wheel becomes faster than the rotation by the motor driving force, so that the motor driving force does not become the load of rotation of the wheel with making the rotation of the wheel preferential.
A tension pulley is provided in the middle portion of a belt to adjust the tension of the belt, so that the loss in transmission of the driving force is reduced by pressing the belt with the tension pulley.
However, this configuration has problems in that the entire casing cannot be made smaller, even if an attempt is made to make it lighter in weight and more compact in shape due to the increased number of the pulleys, and that the number of components increases because the one-way clutch has to be provided as a separate item in addition to the pulley, which takes more time in the assembly operation and increases the cost.
Since the tension pulley has to be used, the casing becomes larger. Further, the number of components is increased, whereby the assembly time is increased and the cost becomes higher.
The present invention was made in view of the above drawbacks, and an object of the invention is to provide a motor-assisted bicycle which is lighter in weight, more compact in shape, has a reduced number of components, and is easier to assemble.
SUMMARY OF THE INVENTION
The motor-assisted bicycle of the present invention comprises a transmission reduction mechanism for transmitting the rotation of a motor and reducing speed, a driving wheel to be driven by a driving force from the transmission reduction mechanism, and a clutch for transmitting only one-way driving force, the clutch being provided to the transmission reduction mechanism.
The transmission reduction mechanism comprises an epicyclic roller reduction mechanism having a plurality of rollers, at least one of the rollers being made different in outer diameter from the other rollers, and a center of at least one of the rollers not being supported with a shaft.
A rotary cylinder to be rotated in inner contact with the outer periphery of the rollers is provided, and the roller not supported with the shaft is in inner contact between a rotary shaft and the rotary cylinder with respect to one-way rotation of the rotary shaft.
The motor-assisted bicycle of the present invention has a transmission reduction mechanism comprising rollers coupled to the rotary shaft, and an output mechanism having an output shaft coupled to a portion except for the coupled portion between the roller and the rotary shaft, and is characterised in that the output shaft is made eccentric around the rotary shaft, and a fixing member for fixing the position of the output mechanism is provided.
The roller comprises a plurality of rollers positioned in contact with the rotary shaft, and the output mechanism, formed to be a cylinder having a bottom, is positioned to allow an outer surface of the roller contact an inner surface of the output mechanism.
The output shaft has a pulley for provision of a ring-shaped transmission member.
The output mechanism is composed of a rotary cylinder to be coupled to the roller, and a cover for covering the rotary cylinder and to be fixed by the fixing member.
The motor-assisted bicycle of the present invention includes a motor driving portion for rotating a driving wheel with the motor as a driving source, and a man power driving portion for rotating the driving wheel with man power as a driving source, and is characterised in that the transmission reduction mechanism is interposed between the motor and the driving wheel.
A hub of the driving wheel comprises a rotational casing rotated by the driving of the motor, and a fixed casing to be fixed oppositely to the rotational casing, and the motor and the transmission reduction mechanism is housed in the hub.
According to the configuration of the present invention, when a rotary shaft of a motor is rotated with an output shaft being in a stop condition, rotation of the rotary shaft is reduced in speed by a transmission reduction mechanism so as to rotate the output shaft. When the rotation of the output shaft is faster than the rotation speed of the rotary shaft, however, the driving force is cut off by a clutch means provided between the output shaft and the rotation shaft with the motor being driven continuously, and the output shaft is rotated with the driving force not reaching the rotary cylinder. In the case where the driving transmission apparatus is used for the motor-assisted bicycle, when the motor is rotated faster than the rotation of the driving wheel, the apparatus is so operated as to transmit power by a one-way clutch, thereby rotation of the rotary shaft is reduced to rotate the output shaft. When the rotation of the motor is slower than the rotation of the driving wheel, power is cut off by a clutch means provided between the output shaft and the rotary shaft so that the motor does not become a burden upon the rotation of the driving wheel.
When the rotary shaft is rotated by the driving of a motor, a roller not supported by the shaft starts its rotation with the driving force. All the rollers begin rotation by receiving power of the rotary shaft with the other rollers being in pressure contact with the rotary shaft. An output shaft of an epicyclic roller reduction mechanism starts its rotation by rotation of all the rollers. When the rotation speed of the rotary shaft is slower than the rotation speed of the output shaft, the roller not supported with the shaft cuts off pressure contact against the rotary shaft, so that pressure contact against the rotary shaft of the other rollers is eliminated, and the output shaft is rotated without receiving the driving force from the rotary shaft. When rotation of a driving wheel is slower than rotation of a motor in the case where the driving transmission apparatus is used for a motor-assisted bicycle, the driving force from the rotary shaft of the motor is reduced by the transmission reduction mechanism and is outputted to the output shaft. When rotation of the driving wheel is faster than rotation of the motor, a roller not supported by the shaft moves in the epicyclic roller reduction mechanism so as to cut off transmission of the driving force, so that the load of the motor is not applied upon rotation of the driving wheel.
In a motor-assisted bicycle including a motor driving portion and a man power driving portion, a driving force of the motor is transmitted by a clutch when the rotation speed of a rotary shaft of the motor is faster than the rotation speed of a driving wheel. When the rotation speed of the driving wheel is faster than the rotation speed of the rotary wheel of the motor, the driving force of the motor is not transmitted to the driving wheel by the clutch so that the load would not be applied upon rotation of the driving wheel. Such a condition is caused when the motor-assisted bicycle runs on a downward path with inertia or when the man power becomes larger than the motor force.
When an assembly operation is conducted in accordance with the present invention, a roller is coupled to a rotary shaft which is a driving source. To adjust the coupling between an output shaft and a member to be coupled to the output shaft, an output mechanism is made eccentric around the rotary shaft of an input mechanism, and is fixed with a fixing member while changing the position of the output shaft, to a posit
Fujiwara Masakatsu
Hirose Yasuo
Yamaguchi Yukifumi
Johnson Brian L.
Klebe M B
Sanyo Electric Co,. Ltd.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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