JPS643717B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a chain adjustment device for a chain drive type vehicle such as a tricycle having two rear wheels.

[Prior Art and Problems] A tricycle equipped with balloon tires for traveling on rough terrain has been proposed and put into practical use, but in such a tricycle, the left and right rear wheels are suspended by a swing arm type rear fork and a shock absorber. In addition, when a chain drive mechanism is adopted as the drive method, a mechanism for adjusting slack in the chain, etc. is required.

By the way, in a two-wheeled vehicle, one rear wheel is rotatably supported by a rear axle fixed between the rear ends of left and right fork members of a rear fork, and a driven sprocket that is provided integrally with this rear wheel and a driven sprocket on the engine side. Due to the structure in which the drive sprocket is connected via a chain, adjustment of the tension of the chain due to loosening of the chain can be done by moving the rear axle back and forth with respect to the rear fork and fixing it at a predetermined position. The chain adjustment mechanism is provided at the rear of the rear fork, making the adjustment work easier.

However, in the above-mentioned tricycle,
Inevitably, the structure is such that the left and right rear wheels are attached to both ends of the rear axle and rotate as a unit, and the rear axle needs to be long and takes the load from the left and right rear wheels. In order to withstand this, the rear axle must be supported by a fixed bearing member, and for this reason, it is difficult to employ the chain adjustment mechanism for two-wheeled vehicles as described above. Even if a chain adjustment mechanism were installed on the bearing member, it would increase the unsprung weight of the shock absorber, the adjustment work would not be easy because it would have to be done by crawling between the left and right rear wheels, and the structure would be complicated. This cannot be an improvement measure due to

The present invention has been made in order to easily adjust the chain when a chain drive mechanism is adopted for a vehicle equipped with such rear two wheels, while meeting the above-mentioned needs. By providing a chain adjustment mechanism on the vehicle body frame and fixedly supporting the rear fork pivot so that it can be moved and adjusted in the longitudinal direction, chain adjustment can be done with a simple structure and a minimum number of parts, and the chain adjustment work can be done easily. This can be done simply and easily from the outside of the vehicle body, which is convenient for maintenance, and there is no need to provide an adjustment mechanism on the rear axle side, which does not cause an increase in the unsprung weight of the shock absorber on the rear axle side. An object of the present invention is to provide a chain adjustment device for a chain drive vehicle having two wheels.

[Means for Solving the Problems] In order to achieve the above-mentioned problems, the present invention pivots the rear fork at the front end to the rear part of the frame in which the engine is arranged via a pivot pin so that it can swing vertically, and A single rear axle with two rear wheels attached to both left and right ends is rotatably supported at the end, and a rear action unit is interposed between the frame and the rear fork to form a swing arm type rear axle. It is a chain-driven vehicle with two rear wheels that constitute a suspension system and a chain attached to a drive sprocket installed on the engine and a driven sprocket installed on the rear axle.The rear fork has its front end pivoted at the rear of the frame. A bearing member is horizontally joined between the rear ends of the fork members spaced apart on both sides of the left and right pair of fork members attached to the frame. A long hole in the front-rear direction is formed in a bracket that protrudes forward and is fixed to the frame tube portion extending in a substantially vertical direction. A fixing device is provided for fixing the support pin to the bracket from the outside, and a support piece bent outwardly at the front of the bracket is screwed through in the front-rear direction, so that the rear end is attached to the fixing device of the pivot pin. The chain adjusting device is characterized in that it includes an adjusting bolt that abuts and a lock nut that fixes the adjusting bolt to the support piece.

[Embodiment] Next, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view of a tricycle for traveling on rough terrain in which the present invention is implemented, FIG. 2 is a perspective view of the same frame, and FIG.
The figure is a plan view showing the rear fork at the rear of the frame.
Figure 4 is an enlarged cross-sectional plan view of the chain adjustment section, Figure 5
The figure is a side view of the same.

The frame 1 includes a head tube 2, a main frame member 3 in the shape of a back bone extending to the rear of the head tube 2, two down tubes 4 arranged from the bottom and rear of the head tube 2 to the rear and further back and upward;
4. It consists of a cross member 5 etc. which joins the rear end of the main frame member 3 and the rear ends of the down tubes 4, 4. The front end of a rear fork 7 is pivotally connected to the L-shaped rear part of the down tubes 4, 4 via a bracket 6 in a swing arm manner, and a bearing is installed between the rear ends of fork members 7a, 7a spaced apart on both left and right sides of the rear fork 7. The member 8 is horizontally joined, and the bearing member 8
A rear suspension unit 9 is interposed between the rear wheel and the cross member 5, and connects them to form a shock absorbing suspension system for the rear wheels. A rear axle 10 is supported horizontally through the bearing member 8, rear wheels 11, 11 are attached to both ends of the rear axle 10, and a driven sprocket 1 is attached to the inside of one of the wheels on the rear axle 10.
2 has a brake disc 14 on the inside of the other wheel.
15 is a brake caliper, and a driven sprocket 12 is connected via a chain 13 to a driving sprocket extending from a transmission case on the engine side.

On the other hand, head tube 2 has upper and lower bridges 1.
6 and 17 are connected in a steerable manner, and the bridges 16 and 1
Reference numeral 7 supports left and right upper members 19a, 19a of a front fork 19 that buffers and suspends the front wheel 18, and a drive unit 2 including an engine is located in the space surrounded by the down tubes 4, 4 and the main frame member 3.
0 has a fuel tank 21 on the front part of the main frame member 3, a seat 22 on the rear thereof, and a handle 23 on the top bridge 16.
However, headlights 24 are attached to the front of the vehicle, and fenders 25 and 26 are attached to the front and rear wheels.

In the above, the plate-shaped bracket 6 is fixedly welded to the front of the L-shaped lower part of the down tubes 4, 4.
is provided with a long hole 6a extending in the front-rear direction, and a long hole 27a extending in the same direction is also provided in the down tube side member 27, which is spaced apart inside the bracket 6. The pivot pin 28 of the rear fork 7 is loosely installed. A cylindrical member 29 is fixed at the tips of the two parallel fork members 7a of the rear fork 7, and the inner diameter portion of this member is fitted around the pivot pin 28 via a bearing 30 and a distance collar 31, and the fork member 7a A side washer 32, a dust seal 33, and a bush 34 are interposed between both ends of the cylindrical member 29, the bracket 6, and the down tube side member 27.

A side collar 35 is fitted into the outwardly extending portion of the bracket 6 of the pivot pin 28.
The small diameter portion 35a of the bracket 6 is fitted into the elongated hole 6a, and the stepped portion 35b at the base of the small diameter portion is brought into contact with the outer wall of the elongated hole 6a of the bracket 6. In the illustrated example, a reinforcing plate 6b is provided on the outer surface of the bracket 6, and A similar long hole 6c is provided,
The peripheral portion of this elongated hole 6c is in contact with the step portion 35c. A threaded portion 28a is formed at the extending end of the pivot pin 28, and a nut 37 is connected to this through a washer 36.
are screwed together, and the pivot pin 28 is tightened to press the side collar 35 in the axial direction and fix it to the bracket 6 side. In the figure, 38 is a rotation prevention pin of the nut 37.

In this way, a fixing device is provided for fixing the pivot pin 28 to the bracket 6 via the side collar 35 with the nut 37.

A support piece 6d bent outward is formed at the front end of the bracket 6, and a lock nut 3 is attached to the rear surface of the support piece 6d.
9, the adjusting bolt 40 passed through the support piece 6d is screwed into the lock nut 39, and the head 40a of the adjusting bolt 40 is attached to the side collar 3 of the fixed part.
5. It is brought into contact with the outer peripheral surface from the front.

In the above, in FIGS. 4 and 5, the right side is the rear wheel 11 side, the left side is the front side, the rear fork 7 is pulled to the left side, that is, the front side by the chain 13, and the pivot pin 28 is the adjuster bolt. 40 heads 4
It is restrained in the illustrated position by the collision between Oa and the outer peripheral surface of the side collar 35. If the chain 13 has become loose and needs to be adjusted, first remove the anti-rotation pin 38, loosen the nut 37, and rotate the adjustment bolt 40, so that the adjustment bolt 40 can stroke. and proceed to the right, that is, backward. As a result, the side collar 35 moves to the right (backward), and the pivot pin 28 moves to the elongated holes 6a, 6.
c, the cylinder member 29 of the rear fork 7 pivoted on the pivot pin 28 also moves, and the driven sprocket 12 of the rear axle 10 supported on the rear end of the rear fork 7 described above also moves together. As a result, the chain 13 is tensioned and the tension can be adjusted. After adjustment, the nut 37 is tightened, the side collar 35 is pressed against the bracket 6 side, the nut 37 is fixed through the anti-rotation pin 38, and the pivot pin 28 is restrained by the adjuster bolt 40, and the chain 13 is held at this position. It will be fixed and held in the adjusted state.

In the illustrated example above, an example applied to a tricycle has been described, but the point is that it is sufficient as long as the rear two wheels have the above structure.
Of course, it can also be applied to vehicles with two front wheels.

[Effects of the Invention] As described above, according to the present invention, the chain can be adjusted simply by loosening the lock nut and operating the adjuster bolt to move the pivot pin in the front and back direction, which makes it possible to adjust the chain by loosening the lock nut and operating the adjust bolt. As a chain adjustment device, the structure is simple and the number of parts is minimal.Furthermore, the adjustment device is not installed on the rear fork side, but on the frame side ahead of the left and right rear wheels, so there is There is no need to crawl into a narrow space to adjust the chain, and work can be done from the outside of the vehicle body, making chain adjustment simple and easy, which is convenient for maintenance. The rear fork has the advantage of not increasing the unsprung weight of this type of vehicle, and the rear fork has a swing arm with a bearing member that supports the rear axle installed between the rear ends of the left and right fork members. As a result, it is possible to create a lightweight structure that can suppress deformation of the rear fork even when an upward load is applied from one of the rear two wheels.
The practical effect is remarkable.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a perspective view of a tricycle, FIG. 2 is a perspective view of a frame,
FIG. 3 is a plan view of the main part, FIG. 4 is a cross-sectional plan view of the pivot portion, and FIG. 5 is a side view. In addition, in the drawing, 1 is a frame, 6 is a bracket,
6a is a long hole, 6d is a support piece, 7 is a rear fork,
7a is a fork member, 8 is a bearing member, 9 is a rear action unit, 10 is a rear axle, 11 is a rear wheel, 12 is a driven sprocket, 13 is a chain,
28 is a pivot pin, 35 and 37 are fasteners, 39 is a lock nut, and 40 is an adjustment bolt.

Claims (1)

[Scope of Claims] 1. A rear fork is pivotally connected at its front end to the rear of a frame in which an engine is disposed via a pivot pin, and two rear wheels are attached to the left and right ends of the rear fork. A swing arm type rear two-wheel suspension system is constructed by rotatably supporting a single rear axle provided on the vehicle, and a rear suspension unit is interposed between the frame and the rear fork. It is a chain-driven vehicle with two rear wheels in which a chain is attached to a driven sprocket installed on the rear axle. A frame tube section, which is formed by horizontally joining a bearing member between its ends, rotatably supports the rear axle within the bearing member, is located in front of the rear wheels on the left and right sides of the rear part of the frame, and extends substantially in the vertical direction. A fixing device that forms a long hole in the front-rear direction in a bracket that protrudes forward and is fixed to the front of the rear fork, and fixes the pivot pin of the front end of the rear fork, which can be moved in the front-back direction by passing through the long hole, to the bracket from the outside. At the same time, an adjustment bolt is provided, and the adjustment bolt is screwed through the support piece bent outward in the front part of the bracket in the front-rear direction, and the rear end abuts the fixing device of the pivot pin. 1. A chain adjustment device for a chain drive type vehicle equipped with two rear wheels, characterized in that a lock nut is provided for fixing the chain.