JPS584669B2 - Power transmission mechanism of motorized bicycle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power transmission mechanism for a motorized bicycle that can be easily modified to almost any type of existing bicycle.

Conventionally, a small engine is attached to the side of the bicycle,
Engine-equipped bicycles (motorcycles, etc.) whose rear wheels are driven by belts have already been proposed.

However, in that case, a pulley must be attached to the rear wheel, which requires extensive modification, poses many problems in terms of cost and maintainability, and the center of gravity shifts to one side, reducing safety and deteriorating the appearance. There was a problem.

As a measure to omit the belt, a method can be considered in which a drive roller directly connected to the crankshaft of the engine applies pressure to the side surface or outer peripheral surface of the tire.

However, in either case, the support mechanism for the reaction force from the tires tends to be complicated, and in the latter case in particular, when the road surface is dirty with mud or the like, the device becomes conspicuously dirty.

The present invention utilizes a front downward frame pipe that is provided below the saddle of an ordinary bicycle, attaches a bracket thereto for supporting a pair of roller holders, and connects a drive roller supported by a pair of holders. The above conventional problem is solved by pressing the idle roller against both sides of the rear tire using the elasticity of the spring, and by connecting the drive roller to the engine with a centrifugal clutch attached to the frame pipe in front of the saddle via a wire. The solution is as follows with reference to the drawings.

In FIG. 3 showing the left side portion of the motorized bicycle according to the present invention, a bracket 3 and its presser foot 4 are attached to a frame pipe 2 extending from a saddle 1 at an angle downward in the front direction (downward to the left in the figure). It is fixed by a pair of bolts 5, 5' and nuts 6, and the bracket 3 faces the central axis (not shown) of the rear tire 7 so as to approach the fender 8 that covers the rear tire 7. It extends to the lower right of the figure).

A pin 9 extending in the circumferential direction of the rear tire 7 is fixed to the tip (rear end) of the bracket 3, a pair of left and right holders 10, 10' are pivoted on the pin 9, and are prevented from coming off with a nut 11. .

The holder 10 has a pair of curved arms 13, 13 protruding from a central boss portion 12 so as to avoid the fender 8.
A holding frame 14 is integrally provided at the tips of both arms 13, 13,
A free roller 16 is rotatably supported on a shaft 15 provided on a holding frame 14.

The shaft 15 is generally oriented in the radial direction of the rear tire 7, and the free roller 16 protrudes from the holding frame 14 toward the tire 7 so as to avoid the fender 8 and face the rubber portion of the rear tire 7.

The free roller 16 can be made of a highly wear-resistant hard synthetic resin (eg, nylon), hard synthetic rubber, light alloy, etc., and has a ball bearing (not shown) in the center.

The boss portion 12 is a tongue piece that comes into contact with the bracket 3, and has a pin hole 18 as shown in FIG. 4, and the pin 9 is fitted into the pin hole 18.

An arm 19 that is approximately orthogonal to the boss portion 12 projects obliquely upward from the boss portion 12, and a clutch lever shaft 22 that is integral with the clutch lever 21 is fitted into a hole 20 provided at the tip of the arm 19.

The arm 19 has a cam plate 23 at its upper end that is curved outward in the vehicle width direction at a generally right angle, and the base of the clutch lever 21 engages with a cam surface 24 of the cam plate 23 .

The cam surface 24 consists of concave portions 24a, 24b and an inclined portion 24c connecting the two as shown in FIG. 5, and the clutch lever 21 moves from the position indicated by the solid line in FIG.
When the cam plate 23 moves in the direction of the arrow B, the cam plate 23 maintains a contact state with the clutch lever 21 by the cam surface due to the elasticity of the spring described later, and moves in the direction of the arrow B, and the clutch becomes in the connected state.

25 and 26 are stoppers provided integrally with the cam plate 23.

The right holder 10' (FIG. 3) has roughly the same shape as the left holder 10, but there is no portion corresponding to the cam plate 23 of the left holder 10.

Two tension coil springs 28 are mounted between the pair of arms 13.13 of the left holder 10 and the pair of arms 13' of the right holder 10'.

Further, as shown in FIG. 2, a drive shaft 30 is supported at two points on the right holder 10' via a pair of bearings 29, and the holding frame 14'
A drive roller 31 fixed to the inner drive shaft 30 avoids the fender 8 and protrudes toward the rubber part of the rear tire 7.

The illustrated drive roller 31 has anti-slip vertical grooves 32 on the outer cylindrical surface.
The free roller 16 mentioned above is made of a light alloy having a
Similarly, it can also be made of hard synthetic resin or hard synthetic rubber.

The upper end of the drive shaft 30 is connected to the rear end (left end in FIG. 2) of the inner wire 33a of the Bowden wire 33, and the front end of the inner wire 33a is connected to the centrifugal clutch 3 as shown in FIG.
Connect to the internal output shaft (not shown) of 4.

The front end of the main body (outer tube) of the Bowden wire 33 is fixed to the case of the centrifugal clutch 34.

Reference numeral 35 in FIG. 1 is an inverted engine, and its crankcase part is connected to a horizontal frame pipe 38 extending forward from the saddle 1 (to the right in FIG. 1) by means of a presser foot 36 and bolts 37.
Fixed.

One end of the slotted cable 40 is connected to the carburetor 39, and the other end of the slotted cable 40 connects to a throttle lever (not shown) on the handle that is easily operated with the right hand.

The exhaust pipe 41 extends downward along the front upward frame pipe 42 and is fixed to the frame pipe 42.

The illustrated engine 35 is a small two-stroke engine used for brush cutters and the like, and has a starter handle on the back side in FIG.

In FIG. 3, the manual clutch consisting of the clutch lever 21, gum plate 23, etc. is in a disengaged state, that is, the clutch lever 21
is located in the large recess 24b of the lift L as shown by the solid line in FIG. Therefore, both the free roller 16 and the drive roller 31 are separated from the rear tire 7.

In this state, use the starter handle to turn the engine 35
the clutch lever 21 in the eight direction of the arrow in Fig. 3.
When the cam plate 23 is operated to position 1', the cam surface 24 of the cam plate 23 pushes the clutch lever 21 due to the elasticity of the spring 28.
Extend in the direction of arrow B while maintaining contact with the (Fig. 5)
, arms 19 and 19' are separated, and arms 13 and 13' are separated.
The free roller 16 and the drive roller 31 are brought into pressure contact with the rear tire 7 due to the elasticity of the spring 28 .

In this state, if you operate the throttle lever to increase the engine rotation, or use the foot pedal to increase the engine rotation while running, the centrifugal clutch 34 is connected, and the rotational force of the engine 35 is transferred to the drive roller 31 through the wire 33a.
, the drive roller 31 rotates in the direction of arrow C, and the rear tire 7 can be driven.

To stop, move the clutch lever 21' (Fig. 3) in reverse A.
direction to disengage the manual clutch, lower engine speed, and apply the brakes.

You can also apply engine braking by lowering the engine speed before disengaging the manual clutch.

As explained above, according to the present invention, (1) since the wire drive system is adopted, the mounting position of the engine 35 can be freely selected.

(2) Can be easily attached to any bicycle.

(3) Free roller 16 and drive roller 31 are connected by spring 2
Since the elastic rollers 8 are brought into pressure contact with both sides of the rear tires 7, the support mechanism for the reaction force that both rollers receive from the tires is greatly simplified, and there is no risk of applying a load to the rear tires 7 in the vehicle width direction. operation is stable for a long period of time.

(4) Since the engine 35 can be placed in the center of the vehicle body, there is no fear that the center of gravity will shift to one side, improving driving safety.

(5) The cost is very low.

(6) Maintenance and adjustment are easy.

Note that when embodying the present invention, in order to keep the Bowden wire 33 as straight as possible, the center line of the crankshaft of the engine 35 and the center line of the drive shaft 30 may be arranged on line D in FIG. can.

In that case, since the distance between the fender 8 and the frame pipe 2 is reduced, the bracket 3 is made to protrude in front of the frame pipe 2, and the shape of the arms 13 and 13' is largely curved so as to bypass the frame pipe 2 and the fender 8. Good.

Examples in that case are shown in FIG. 6 and below.

Depending on the model of the engine, it is also possible to attach the engine to the front upward frame pipe 42.

In FIGS. 6 to 9, the same reference numerals as those in FIGS. 1 to 5 indicate corresponding parts.

The bracket 3 in Fig. 7 extends in the front and back direction and has two long holes 4.
5 and two welding bolts 46, the bolts 46 are passed through holes in a presser foot 47, and the bolts 46 are fastened to the front downward frame pipe with nuts 48.

The pin 9 (FIG. 6) can be fixed at any position within the elongated hole 45, thereby making it possible to adjust the position of the holders 10, 10' in the longitudinal direction.

In other words, it is convenient when adjusting the chain or because the dimensions of the front down pipe and rear tire are different for each bicycle.

Two elongated holes 45 are provided, and the vertical width of the holder 10, 10' mounting portion is widened to reduce vertical wobbling.

Since the roller 31 is tapered, the contact surface is increased and slippage can be prevented.

[Brief explanation of the drawing]

Fig. 1 is a partial perspective view of the right side of a bicycle with an engine according to the present invention seen from slightly behind, Fig. 2 is an enlarged view of a part of Fig. 1 as seen in the direction of arrow E, and Fig. 3 is from the left side. 4 is a schematic cross-sectional view taken along the line ■-■ in FIG. 3, FIG. 5 is a cross-sectional view taken along the line ■-■ in FIG. 4, and FIG. 6 is a perspective view showing another embodiment. Fig. 7 is an exploded perspective view of the bracket in Fig. 6, Fig. 8 is a plan view and left side view showing the relationship between the clutch lever and cam plate in Fig. 6 when the clutch is disengaged, and Fig. 9 is a left side view thereof. They are a plan view and a left side view of the same showing the relationship when the clutch is connected. 1...Saddle, 2...Front downward frame pipe, 3.
...Bracket, 7...Rear tire, 9...Pin,
10,10'...Holder, 15...Shaft, 16...
・Free roller, 21...Clutch lever, 28・
... Spring, 30... Drive shaft, 31... Drive roller, 33... Bowden wire, 34... Centrifugal clutch, 35... Engine.

Claims (1)

[Claims] 1.Support a pair of left and right holders on the bracket fixed to the lower front reframe pipe below the saddle via pins facing approximately in the circumferential direction of the rear tire, and extend each holder over the side of the rear tire. One holder supports a free roller via a shaft in the radial direction of the rear wheel, and the other holder supports a drive roller with a drive shaft also in the radial direction of the rear wheel. A spring that presses against the side of the tire and a manual crack mechanism that separates both rollers against the spring's elasticity are installed. An engine with a centrifugal clutch is fixed to a frame pipe in front of the saddle, and the output shaft of the centrifugal clutch is connected to the rollers via a wire. A power transmission mechanism for a motorized bicycle characterized by being connected to a drive shaft.