JPH0159149B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a shift position of a bicycle that can be automatically and continuously changed, and is used in the field of manufacturing bicycles.

(Prior Art) As a conventional bicycle transmission device, a multi-gear transmission structure has been widely put into practical use. In addition, the applicant previously proposed a structure using an oil motor as a device capable of continuously variable speed (Japanese Patent Application No. 59-9738).
(Japanese Patent Application Laid-open No. 154975/1983).

(Problems to be Solved by the Invention) As described above, in the structure of changing multi-stage gears, the gears are shifted manually and in stages, and in order to increase the number of gears, it is necessary to increase the number of gears, and the structure There is a risk that the process will become complicated, and furthermore, the operation will become cumbersome. Furthermore, since the gear cannot be changed while the vehicle is stopped, there is a problem in that if the vehicle is stopped with the high-speed gear selected, a large amount of force is required to restart the vehicle.

On the other hand, the structure using the oil motor has the problem of large power loss.

(Means for Solving the Problems) In the transmission device of the present invention, a pedal shaft is installed on the frame of a bicycle so as to be able to rise and fall freely, a variable pulley is attached to the pedal shaft, and a driven shaft above the variable pulley is connected to the pedal shaft. The sprocket wheel is installed parallel to the shaft, and a sprocket wheel for attaching a chain that transmits rotation to the driven pulley and the rear wheels of the driven shaft is fixed, and a belt is installed between the variable pulley and the driven pulley.

As long as the pedal shaft has a structure that allows it to move up and down a distance corresponding to the depth of the groove of the variable pulley, a conventionally known elevating structure can be used for its specific mounting state.

Further, if the driven pulley is a toothed pulley, for example, and the belt is made of a toothed type that engages with this pulley in series, there will be no slippage and force can be transmitted efficiently, but V pulleys and other known pulleys can be used.

(Operation of the Invention) In the present invention, the rotational force of the pedal shaft is transmitted to the driven shaft via the variable pulley, the belt, and the driven pulley, and the sprocket wheel rotates.

If you try to rotate the pedal shaft by applying force to the pedal when a large torque is required, such as during initial movement, the pedal shaft will descend and the belt will rotate while contacting the small diameter part of the variable pulley. The reduction ratio between the pedal shaft and the sprocket shaft is increased, and the wheel rotates at a relatively low speed and with a large force. As the running resistance of the bicycle decreases and the force applied to the pedals weakens (as the torque decreases), the pedal shaft gradually rises, and the belt rotates while contacting the large diameter portion of the variable pulley, so that the pedal shaft and sprocket shaft are aligned. During this period, the reduction ratio becomes small and the sprocket wheel rotates at a relatively high speed.

Since the pedal shaft always moves up and down in response to the force applied to the pedal (torque of the pedal shaft), continuously variable speed is possible.

As described above, the device of the present invention allows stepless speed change without any special operation, so it is suitable for use as an alternative to indoor health bicycles, and is suitable for use as a health bicycle for the elderly and women. It is meaningful as such.

Embodiments of the present invention will be described below with reference to the drawings.

(Example) One end of pedal shaft mounting rods 2, 2 is rotatably fixed to a bicycle frame 1 by a shaft 3, and a pedal shaft 4 is rotatably mounted to the other end of the mounting rods 2, 2. A variable pulley 5 is fixed to the pedal shaft 4.

The variable pulley 5 includes two conical disks 6, 6 fitted so as to be movable in the axial direction of the pedal shaft 4, and springs 7, 7 that bias the disks 6, 6 toward opposite sides. and spring casing 8,8
and stoppers 9,9.

Above the variable pulley 5, bearings 10, 10 for mounting a driven shaft are fixed to the frame 1, and a driven shaft 11 of the bearings 10, 10 is mounted parallel to the pedal shaft 4. The driven shaft 1
A driven pulley 12 is attached to the wheel 1 in correspondence with the variable pulley 5, and a sprocket wheel 13 is attached to one side of the wheel 1 to construct a chain for transmitting rotation to the rear wheel.

The driven pulley 12 has a tooth pattern 14 on its peripheral wall, and a V-belt 16 having a trapezoidal cross section and a tooth pattern 15 on its inner surface is mounted between the variable pulley 5 and the driven pulley 12. 17 in the diagram
is a pedal rod, and 18 is a pedal.

According to the device shown in the above embodiment, when a large torque is required such as when starting or climbing a slope, the pedal 18
By strongly depressing, the mounting rod 2 rotates as shown by arrow 19 in FIG. 2, and the variable pulley 5
is descending. When the variable pulley 5 descends, the V-belt 16 is deeply inserted between the disks 6, 6, so the disks 6, 6 slide in the direction of arrows 20, 20a in FIG. 1 against the springs 7, 7, and the V-belt 16 It comes into contact with the small diameter portion of the variable pulley 5. Therefore, the reduction ratio between the pedal shaft 4 and the driven shaft 11 increases.

On the other hand, if you reduce the force with which you press the pedal 18,
Since the disks 6, 6 are pushed by the springs 7, 7 and move in opposite directions, the V-belt 16 comes into contact with the large diameter portion of the variable pulley 5. Therefore, the reduction ratio between the pedal shaft 4 and the sprocket shaft 11 becomes small.

In the above, the distance between the disks 6 and 6 is equal to the distance between the pedals 18
The speed is determined by the force with which you press the button, and the speed is automatically continuously variable.

(Effects of the Invention) That is, according to this invention, since the rotation of the pedal shaft is transmitted to the sprocket wheel via the variable pulley, a reduction ratio corresponding to the pedal depression force can be obtained, and the ,
It has the advantage of being able to perform stepless speed change, and there is no difference in power loss from conventional multi-speed transmissions.

[Brief explanation of drawings]

FIG. 1 is a front sectional view of an embodiment of the invention, FIG. 2 is a side sectional view of the same, and FIG. 3 is a side view of a bicycle to which the device of the invention is installed. 1...Frame, 2...Mounting rod, 4...Pedal shaft, 5
...variable pulley, 11...driven shaft, 12...driven pulley, 13...sprocket wheel, 1
4, 15...tooth pattern, 16...belt.

Claims (1)

[Scope of Claims] 1. A variable pulley is fixed to a pedal shaft that is attached to a bicycle frame so as to be able to rise and fall freely, and a driven pulley above the variable pulley is fixed to a driven shaft that is parallel to the pedal shaft. A bicycle transmission device in which a belt is attached between pulleys and a sprocket wheel is fixed to the driven shaft. 2. The bicycle transmission device according to claim 1, wherein the pedal shaft is rotatably attached to the other end of a swinging member whose one end is rotatably attached to the frame of the bicycle. 3. The bicycle transmission device according to claim 1, wherein the driven pulley is a V-pulley or a pulley having tooth patterns on its outer circumferential surface. 4. The bicycle transmission device according to claim 1, wherein the belt has a trapezoidal cross section and has tooth patterns arranged in series on the inside.