JPH09221084A - Bicycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel design of a bicycle and to simplify the structure for covering a driving part. SOLUTION: A frame 2 of a bicycle 1 consists of a tubular frame body 7, a suspension fork 10 rotatably supported by a head portion 21 and a driving case 8 having a hanger portion 16, the driving case 8 being at least partly housed within the frame body 7. A steering part 3 includes a handle 11 attached on the top of the front fork 10. A running part 5 includes a rear wheel 13 attached on the rear end of the frame body 7 and a front wheel 12 attached on the lower end of the suspension fork 10. A driving part 4 includes a crank 30 rotatably supported by the hanger portion 16, a speed increasing part disposed within the driving case 8 for increasing and transmitting the rotational speed of the crank 30 and a tansmitting part 33 for transmitting the increased rotational speed to the rear wheel within the frame body 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bicycle, and more particularly to a bicycle that advances by increasing the rotation of a crank and transmitting it to the rear wheels.

[0002]

2. Description of the Related Art Generally, a bicycle includes a frame (an example of a vehicle body portion) including a frame body obtained by welding pipe materials and a front fork, a steering portion including a steering wheel, and rear wheels and front wheels. It is provided with a traveling unit and a drive unit for rotating the rear wheels. The drive unit has drive components including a crank with a sprocket, which is rotatably supported by a hanger portion of a frame body and has a pedal attached to a tip thereof, a sprocket attached to a rear wheel, and a chain hung between two sprockets. ing. Around this chain is usually
The chain cover is installed so as to cover the entire circumference of the chain to prevent the chain from being caught between the sprocket and the chain due to the exposure of the chain to the outside and from being soiled by the oil or rust on the chain. There is.

[0003]

In the above-mentioned conventional bicycle, the chain cover is attached to prevent the chain from being exposed, so that the clothes can be prevented from being caught or soiled by the chain. However, since the chain cover is attached separately from the frame, it is troublesome to attach the chain cover during manufacturing, and the number of parts increases.
In addition, the design of the chain cover that covers the entire circumference of the chain is almost fixed due to its function and there are restrictions on the design, so it is difficult to bring out the novelty of the design of the entire bicycle.

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel design of the bicycle as a whole and to cover a drive component such as a chain with a simple structure.

[0005]

A bicycle according to a first aspect of the present invention includes a vehicle body section, a steering section, a traveling section, and a drive section. The vehicle body part has a cylindrical frame body having a head part in the front part, a front fork rotatably supported by the head part, and a hanger part mounted so that at least a part of the frame part is housed inside the drive part. Includes case and. The steering section is attached to the upper part of the front fork. The traveling part includes a rear wheel mounted on the rear part of the frame body and a front wheel mounted on the lower end of the front fork. The drive unit includes a crank rotatably supported by the hanger, a speed increasing unit provided in the drive case for increasing the speed while transmitting the rotation of the crank, and a rotation speed increased by the speed increasing unit in the frame body. And transmission means for transmitting to the rear wheel.

In this case, the speed increasing means of the drive portion is provided in the drive case of the vehicle body portion, and the transmission means is provided in the frame body, so that the vehicle body portion covers the drive portion. Parts can be covered with a simple structure. Also, since the chain cover is not required, it is possible to bring about novelty in the design of the entire bicycle. A bicycle according to claim 2 is the bicycle according to claim 1, wherein the speed increasing means is connected to a first sprocket mounted on a rotary shaft of a crank in the drive case and a transmission means in the drive case. It has a second sprocket having a smaller number of teeth than one sprocket, and a chain hung on two sprockets. In this case, since the chain is housed in the drive case, the chain can be covered with a simple structure.

The bicycle according to claim 3 is the bicycle according to claim 1 or 2.
In the bicycle described in [1], the frame body includes a tubular main frame having a head portion fixed to a front portion thereof, a back fork extending downward from the rear end of the main frame in two forks, and a rear end of the main frame. And a seat stay having a saddle attached to the upper end thereof extending obliquely upward from the transmission means, and the transmission means is disposed inside one of the back forks. In this case, since the transmission means is arranged on the back fork, the transmission means can be covered with a simple structure.

The bicycle according to claim 4 is the bicycle according to claims 1 to 3.
In the bicycle according to any one of items 1 to 3,
The rotation increased by the speed increasing means is further increased in speed and transmitted to the rear wheels. In this case, the speed can be increased in two steps,
The speed increasing ratio of the speed increasing means can be reduced, the drive case can be made more compact, and the design can be made more preferable.

[0009]

1 shows a bicycle 1 according to an embodiment of the present invention. The bicycle 1 includes a frame 2 as a vehicle body portion including a suspension fork (an example of a front fork) 10, a steering portion 3 including a handle 11 fixed to an upper end of the suspension fork 10, and a central portion to a rear portion of the frame 2. Drive unit 4
And a traveling unit 5 including front and rear wheels 12 and 13 arranged in front of and behind the frame 2, and a braking unit 6 including front and rear brakes 14 and 15 for braking the front and rear wheels 12 and 13.

The frame 2 is a suspension fork 1
In addition to 0, it mainly includes a frame body 7 having a tubular structure, and a drive case 8 attached to a lower portion of the frame body 7. The frame body 7 mainly includes a main frame 20 having a modified oval cross section that is arranged substantially horizontally and has a cavity inside, a head portion 21, a back fork 22, and a seat support portion 23.

The front portion of the main frame 20 is bent and extends upward, and a head portion 21 is formed at the tip thereof. The head portion 21 is obliquely arranged along the rotation axis X whose upper portion is slightly inclined rearward. The back fork 22 is bifurcated from the rear portion of the main frame 20 and extends obliquely downward. Rear wheel 1 at the rear end of the back fork 22
3 is attached. The back fork 22 also has a space inside. The seat support portion 23 extends obliquely upward from the rear portion of the main frame 20. Inside the seat supporting portion 23, a seat stay 24 made of a pipe material whose upper portion is inclined obliquely rearward is attached. Seat stay 24
The seat post 26 has a saddle 25 fixed to the upper end.
Is fixed so that it can move up and down.

The drive case 8 is attached to the rear portion of the lower surface of the main frame 20 with its upper portion tilted backward. The drive case 8 has a hanger portion 16 that rotatably supports the crank 30 in the lower portion. As shown in FIG. 2, the drive case 8 is a housing having a two-divided structure that can be divided into right and left parts, and a mounting protrusion 17 protruding upward is formed on the upper end surface thereof. The protrusion 17 is fitted inside from the lower end of the seat stay 24. Right hanger 18a on hanger 16
A right bearing 18 composed of a steel ball 18b and a left bearing 19a and a right bearing 19 composed of a steel ball 19b are mounted, and a crankshaft 34 constituting a crank 30 is rotatably supported by these bearings 18 and 19. ing.

The head portion 21 is the suspension fork 1
0 is rotatably supported around the rotation axis X. Steering section 3
Has a handle 11 fixed to the upper end of the suspension fork 10. At both ends of the handle 11,
A pair of front and rear brake levers 27 that constitute the braking unit 6
Is attached. Each brake lever 27 is connected to the front and rear brakes 14 and 15 by a brake wire 28.

The drive unit 4 includes a crank 30 rotatably supported by the hanger unit 16, a speed increasing unit 32 for speeding up the rotation of the crank 30, and a driving force increased by the speed increasing unit 32 for the rear wheels. It has a transmission part 33 which transmits to 13. Crank 3
2, 0 is a crank shaft 34, a pair of left and right crank arms 35a, 35b whose base ends are fixed to both ends of the crank shaft 34 so as to form an angle of 180 degrees, and crank arms 35a, 35a. 35b has a pedal 36 rotatably attached to the tip thereof.

The speed increasing portion 32 is stretched over the first sprocket 41 mounted on the middle of the crankshaft 40, the second sprocket 42 arranged on the upper part of the drive case 8, and the two sprockets 41, 42. The speed increasing chain 43 is included. The number of teeth of the first sprocket 41 is, for example, "39", and the number of teeth of the second sprocket 42 is less, for example, "13". As a result, the speed increasing unit 32 can speed up the rotation of the crank 30 three times. Second
The sprocket 42 has bearings 45,
It is attached to an output shaft 47 which is rotatably supported by 46. One end of the output shaft 47 projects outside the main frame 20 from the side of the drive case 8.

The transmission portion 33 includes a third sprocket 48 attached to the protruding end of the output shaft 47, and a sprocket (not shown) attached to the third sprocket 48 and the rear wheel 13.
And a chain 49 hung on two sprockets. The number of teeth of the third sprocket 48 is the same as the number of teeth of the sprocket mounted on the rear wheel and is, for example, “1”.
3 ".

In the bicycle having such a structure, the chain 4
Since all driving components such as 3, 49 and sprockets 41, 42, 48 are housed in the frame 2, the driving components can be covered with a simple structure without providing a chain cover or the like. Therefore, the clothes are not dirty and the clothes are not caught between the chain and the sprocket. Further, since it is not necessary to provide a chain cover, the restriction on the design by the chain cover can be released and the novelty of the design of the entire bicycle can be achieved.

Further, since the speed increasing chain 43 is not directly hung from the first sprocket 41 to the sprocket mounted on the rear wheel 13, but is hung on the second sprocket 42 arranged above, the hanger. Part 16 and rear wheel 13
There is a space between and. Therefore, even if the bicycle rides on a curb such as a sidewalk, it is less likely that the curb will contact the chain or back fork and damage them.

Next, the speed-up operation of the above embodiment will be described. When the rider depresses the pedal 36 to rotate the crank 30, the first sprocket 41 rotates, and the rotation is transmitted to the second sprocket 42 via the speed increasing chain 43. At this time, the rotation of the crank 30 is tripled by the gear ratio of the two sprockets 41, 42.
This rotation is transmitted to the rear wheel 13 via the output shaft 47, the third sprocket 48 and the chain 49. As a result, the rear wheel 13 rotates at a rotational speed three times the rotational speed of the crank 30, and the bicycle 1 moves forward.

[Other Embodiments] (a) In the transmitting portion 33, the number of teeth of the third sprocket is made larger than the number of teeth of the sprocket mounted on the rear wheel 13,
The transmission unit 33 may also increase the speed. In this case, since the speed increasing ratio in the speed increasing unit 32 can be reduced, the diameter of the first sprocket 41 is reduced, and the drive unit 4 is more compact.

(B) The structure of the speed increasing portion 32 and the transmitting portion 33 is not limited to the chain and the sprocket.
The speed may be increased by using a bevel gear, a planetary speed increasing mechanism, or another mechanism such as a belt.

[0022]

In the bicycle according to the present invention, since the speed increasing means of the driving portion is provided in the driving case of the vehicle body portion and the transmitting means is provided in the frame body, the vehicle body portion covers the driving portion. Therefore, the driving component can be covered with a simple structure. Also, since the chain cover is not needed,
You can bring out the novelty in the design of the entire bicycle.

[Brief description of drawings]

FIG. 1 is a partial side sectional view of a bicycle according to an embodiment of the present invention.

FIG. 2 is a sectional view of a drive unit.

[Explanation of symbols]

 1 Bicycle 2 Frame 3 Steering part 4 Driving part 5 Traveling part 7 Frame body 8 Driving case 10 Suspension fork 16 Hanger part 20 Main frame 21 Head part 22 Back fork 30 Crank 32 Accelerating part 33 Transmission part 34 Crankshaft 35a, 35b Crank Arm 41 1st sprocket 42 2nd sprocket 43 Speed-up chain

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koji Hiramoto 1-1-1 Kidamotomiya, Neyagawa City, Osaka Prefecture EXEDY Corporation

Claims (4)

[Claims] 1. A hanger portion which is mounted so that at least a part thereof is housed inside a tubular frame body having a head portion at a front portion, a front fork rotatably supported by the head portion, and the frame body. A travel including a vehicle body portion including a drive case having a steering wheel, a steering portion mounted on an upper portion of the front fork, a rear wheel mounted on a rear portion of the frame body, and a front wheel mounted on a lower end of the front fork. Portion, a crank rotatably supported by the hanger portion, a speed increasing means provided in the drive case for increasing the speed while transmitting the rotation of the crank, and a rotation speed increased by the speed increasing means. A drive unit including a transmission unit that transmits the rear wheel in the frame body. 2. The speed increasing means includes a first sprocket mounted on a rotary shaft of the crank in the drive case, and a first sprocket having a smaller number of teeth than the first sprocket connected to the transmitting means in the drive case. It has two sprockets and a chain hung on the two sprockets,
The bicycle according to claim 1. 3. The frame body includes a tubular main frame having the head portion fixed to a front portion thereof, a back fork extending downwardly from a rear end of the main frame into two forks, and a main frame of the main frame. The bicycle according to claim 1 or 2, further comprising a seat stay extending diagonally upward from a rear end and having a saddle attached to an upper end, wherein the transmission means is disposed inside one of the back forks. . 4. The bicycle according to claim 1, wherein the transmission means further accelerates the rotation speed increased by the speed increasing means and transfers the rotation to the rear wheel.