JP2000168664A - Frame for bicycle with rear suspension - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize restriction of shape designing of a frame for a bicycle by internally installing a shock absorber storing an elastic member in an outside cylinder in a hollow part of a central lug. SOLUTION: A shock absorber 12 is constituted of a device storing a thing clamping both sides of a piston with rubber in an outside cylinder. The piston is installed on a piston connecting part 10 of a chain stay bridge 8, and a shock absorbing function is displayed. Additionally, the shock absorber 12 is completely stored in a hollow part of a central lug 5 and fixed in the central lug 5 by a dowel fitting 11. Hereby, as the dowel fitting has a small play, the shock absorber 12 is free to oscillate in the hollow part of the central lug 5 in the case when excessive impact force works. Consequently, no restriction is given to freedom of shape designing of an inside diameter and a front frame of a main pipe.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bicycle frame having a rear suspension in which a front frame and a rear frame of a bicycle are rotatably connected to each other and a shock absorber is interposed between the front frame and the rear frame. .

[0002]

2. Description of the Related Art As a shock absorbing method for a bicycle, a method in which a shock absorbing device is attached to a saddle portion or a front fork on a front wheel side is widely known. In recent years, a bicycle with a rear suspension incorporating a shock absorbing device in a frame itself has been used. Various frames have been proposed. The device disclosed in Utility Model Registration No. 3049341 is an example of such a device.
As a configuration of the rear suspension, a spring material was directly incorporated in a main pipe called a top tube.

[0003] However, in a system in which parts such as a piston and a spring serving as a shock absorber are directly accommodated in the main pipe and slidably contact the inner surface of the pipe, the inner diameter accuracy of the main pipe and the smoothness of the inner surface greatly affect the performance of the shock absorber. In addition, when the shock absorber is damaged, the entire frame needs to be replaced. Therefore, if the piston and spring, etc. are housed in one case and used as a shock absorber as a single component and mounted in the main pipe, problems such as the inner diameter accuracy of the main pipe can be solved. However, a new problem arises in that the outer diameter of the shock absorber is increased and the diameter of the main pipe needs to be further increased, and the degree of freedom in the shape design of the front frame is restricted.

Further, in order to sufficiently exert the function of the shock absorber, it is required that the rotation of the connecting portion between the front frame and the rear frame is smooth and highly reliable. However, the structure becomes complicated if the rotation connection part is provided in a place different from the crankshaft part, and even if the rotation connection part is provided concentrically with the crankshaft part, the conventional Hungawan cannot be used and special parts Is required.

[0005]

SUMMARY OF THE INVENTION The present invention is an improvement on such a conventional bicycle frame with a rear suspension. An object of the present invention is to reduce the restrictions on the shape design of the bicycle frame by mounting a shock absorber and a rotation connecting portion.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the gist of the present invention is to provide at least a front frame including a main pipe, a head lug, and a Naka lug and a rear frame including a chain stay. A bicycle frame with a rear suspension in which a shock absorber is interposed between the front frame and the rear frame, a shock absorber in which an elastic member is housed in an outer cylinder in the hollow portion of the Nakaragu. A bicycle frame with a built-in rear suspension.Preferably, when pivotally connecting the front frame and the rear frame, the hanger lug connected to the lower part of the Nakalug and a pair of left and right brackets connected to one end of the chain stay are cranked. It is concentrically connected to the shaft.

Further, as a structure of the rotation connecting portion, a hanger lug and a bracket are connected by fitting a flanged cap into each of a pair of brackets and inserting a hollow bolt into a center hole of the flanged cap. Preferably, a screw for attaching a hanger one is provided inside the flanged cap, and a projection is provided on the flange of the flanged cap so as to match the hole of the bracket.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION A bicycle frame with a rear suspension according to the present invention comprises a front frame and a rear frame. The front frame is obtained by welding a head lug and a Naka lug to both ends of a main pipe, further attaching a vertical pipe to the upper part of the Naka lug, and attaching a hanger lug to the lower part. Here, the main pipe may be divided into two, a wow pipe and a sita pipe, to share the load.
In the rear frame, one end of two chain stays is integrated by a chain stay bridge, and a pair of left and right brackets is welded to the end.

The shock absorber used in the present invention comprises an outer cylinder containing an elastic member made of an elastomer such as rubber or a coil spring and a piston, and the piston connected to the chain stay bridge of the rear frame is connected to the outer cylinder. The buffer function is exhibited by moving inside. Although the outer diameter of this shock absorber is increased by the amount of the outer cylinder, in the present invention, since it is installed in the hollow portion of the Nakaragu, there is no restriction on the inner diameter of the main pipe and the degree of freedom in the shape design of the front frame. . That is, since the inner diameter of the Nakarag is larger than the inner diameter of the main pipe, it is possible to easily have a space in which the shock absorber can be installed, and the shock absorber is not protruded from the main pipe side of the Nakarug. Even if the shock absorber has an outer cylinder, the shock absorber can be sufficiently accommodated in a normal lug having a normal inner diameter, and does not affect the main pipe.

Also, if the buffer is provided with a flange and fixed with a fitting having some play with the flange provided at the opening on the rear frame side of the Nakaragu, the buffer itself becomes somewhat less in the hollow part of the Nakaragu. Therefore, even if an excessive impact force is applied, no excessive force is applied to the shock absorber, so that the shock absorber can be prevented from being damaged.

In the present invention, the front frame and the rear frame are rotatably connected concentrically with the crankshaft by inserting hanger lugs inside a pair of left and right brackets.
When the rotating portion is concentrated on the crankshaft portion in this manner, the buffering performance and other reliability are improved by the simpler structure than when a separate rotating connection portion is provided. As the structure of the rotation connection part, a flanged cap is inserted from both sides into holes provided in a pair of left and right brackets, a hollow bolt is inserted into one center hole of the flanged cap, and fastened with a nut from the other By doing so, the hanger lug and the bracket are connected.

Here, if the hollow bolt for fastening has at least an inner diameter hole through which a conventional crankshaft can be inserted, the crankshaft can be attached without using special parts. Further, the hollow bolt may be integrated with the left or right flanged cap by welding or the like, and in fixing the nut, the fastening can be more reliably performed by using a double nut or an adhesive together. . Furthermore, by applying a female thread for attaching the hanger one to the inside of the flanged cap, the conventional hanger one can be attached, the crankshaft can be held, and when the flanged cap is inserted into the insertion hole of the bracket. In addition, if the flange of the flanged cap is provided with a projection that can match the small hole provided in the bracket, it is possible to prevent co-rotation when attaching the conventional hanger one.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view showing a bicycle frame with a rear suspension according to the present embodiment. The front frame has a head pipe 1 welded to one end of a main pipe including a wow pipe 2 and a sita pipe 3, and another end of the wow pipe 2. The Naka lug 5 is formed by welding a hanger lug 6 to the other end of the Sita pipe 3. The vertical pipe 4 is welded to the upper part of the Naka lug 5, and the hanger lug 6 is welded to the lower part. Here, the wow pipe 2 has the same diameter over the entire length and draws a gentle arc, and is shaped by a free design. The Naka lug 5 has a hollow portion that is larger than the Wawa pipe 2, and thereafter the buffer device 12 is provided on the frame side.
Has an opening with a flange for housing therein.

On the other hand, the rear frame is formed by integrating one end of two chain stays 7 with a chain stay bridge 8 and providing a pair of left and right brackets 9. Here, the chain connection 8 has a piston connection portion 1 of the shock absorber 12.
0 is provided, and the bracket 9 is provided with a hole into which the flanged cap 13 is inserted.

The shock absorber 12 in the present embodiment comprises a piston in which both sides of a piston are sandwiched by rubber and accommodated in an outer cylinder. Then, as shown in FIG. 2, the piston is attached to the piston connecting portion 10 of the chain stay bridge 8 so as to exhibit a cushioning function. Further, the shock absorber 12 is completely stored in the hollow portion of the Naka lug 5, and is fixed to the Naka lug 5 by the fitting 11. Here, fitting 1
Since there is some play in 1, the shock absorber 12 can swing in the hollow portion of the Naka lug 5 when an excessive impact force is applied.

As shown in FIG. 3, the hanger lug 6 of the front frame is inserted into a pair of left and right brackets 9 of the rear frame, and is rotatably connected concentrically with the crankshaft. At the time of connection, the flanged cap 1 with the hollow bolt 14 welded thereto
3A and the cap with flange 13B are inserted from both sides of the bracket 9 and fastened with the nut 15. Flanged cap 13A
A female thread 16 is formed inside (13B) so that a general hanger one can be attached, so that a crankshaft (not shown) can be held.
Further, the flanged caps 13A and 13B are provided with projections 17, which are aligned with the small holes 18 provided in the bracket 9 to prevent the circling when the hanger one is attached.

[0017]

According to the present invention, a front frame including at least a main pipe, a head lug, and a Naka lug is rotatably connected to a rear frame including a chain stay, and a shock absorber is interposed between the front frame and the rear frame. In the bicycle frame with the rear suspension, the shock absorber in which the elastic member is housed in the outer cylinder is provided in the hollow portion of the Nakaragu, so that the inner pipe of the main pipe and the degree of freedom in the shape design of the front frame are restricted. The front frame and the rear frame are rotatable by connecting the hanger lug connected to the lower part of the Naka lug and the pair of left and right brackets connected to one end of the chain stay concentrically with the crankshaft. And high reliability such as buffer performance.

Furthermore, a flanged cap is inserted into each of a pair of left and right brackets, and a hanger lug and a bracket are connected by inserting a hollow bolt into a center hole of the flanged cap, so that the crank is used without using special parts. The shaft can be mounted, and the hanger one mounting screw is provided inside the flanged cap, so the conventional hanger one can be mounted, and the flange of the flanged cap is provided with a protrusion that can match the hole of the bracket Therefore, it is possible to prevent co-rotation when attaching Hungawan.

[Brief description of the drawings]

FIG. 1 is a side view showing a bicycle frame with a rear suspension.

FIG. 2 is a side view showing a rear suspension portion.

FIG. 3 is a perspective view showing a rotation connecting portion between a front frame and a rear frame.

[Explanation of symbols]

 1 ‥ Head pipe 2 ウ Main pipe wow pipe 3 ‥ Main pipe shrink pipe 4 ‥ Vertical pipe 5 ‥ Nakarag 6 ラ グ Hanger lug 7 ‥ Chain stay 8 ‥ Chain stay bridge 9 ‥ Bracket 10 ‥ Piston connection 11 ‥ Mating fitting 12 ‥ Bumper 13, 13A, 13B {Cap with flange} 14> Hollow bolt 15> Nut 16> Female thread 17> Projection 18> Small hole

Claims (5)

[Claims] At least a main pipe, a head lug,
In a bicycle frame with a rear suspension in which a front frame made of Nakaragu and a rear frame made of a chain stay are rotatably connected and a shock absorber is interposed between the front frame and the rear frame, the inside of the hollow portion of the Nakarug is provided. A bicycle frame with a rear suspension, wherein a shock absorbing device in which an elastic member is accommodated in an outer cylinder is provided. 2. By connecting a hanger lug connected to a lower portion of the Naka lug and a pair of left and right brackets connected to one end of a chain stay concentrically with a crankshaft,
The bicycle frame with a rear suspension according to claim 1, wherein the front frame and the rear frame are rotatable. 3. The hanger lug and the bracket are connected by fitting a flanged cap into each of the pair of brackets and inserting a hollow bolt into a center hole of the flanged cap. Bicycle frame with rear suspension. 4. The bicycle frame with a rear suspension according to claim 3, wherein a hanger one mounting screw is provided inside the flanged cap. 5. The bicycle frame with a rear suspension according to claim 4, wherein a projection is provided on a flange of the flanged cap so as to be able to match a hole of the bracket.