JP2010274908A - Front wheel buffer structure for bicycle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a front wheel buffer structure for a bicycle being easy in assembly operation, being inexpensive and being simple in structure. <P>SOLUTION: The front wheel buffer structure for a bicycle is characterized in that it is provided with a front fork blade part 11 representing an elastic member 13 connected so as to be formed between a linear support pipe 12 and an axle bearing 14 and that the front fork blade part 11, a mudguard 20, and a mudguard stay 30 form substantially a triangle-shaped truss structure at a lateral view. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a bicycle front fork and a structure of a bicycle front wheel including the same, and more particularly to a bicycle front fork including a shock absorbing structure and a structure of a bicycle front wheel using the same.

  Conventionally, as a means for improving the riding comfort of a bicycle, it has been proposed to incorporate a buffer structure in a front fork. In one of the conventional buffer structures of this type, a pair of support pipes extending downward from the crown portion of the front fork and a sliding pipe having a bearing portion for receiving a front wheel axle provided at the lower end are mutually nested. A pair of fork blade portions that can be expanded and contracted are configured. An elastic member that receives a compressive force when both pipes fitted to each other contract in a sliding pipe of the fork blade portion is disposed, and the impact relaxation of this elastic member improves the riding comfort of the bicycle. Is planned.

Further, as another structure of this type of conventional buffer structure, a base end of a swing arm having a front wheel mounting portion is rotatably connected to a lower end portion of the front fork, and between the front fork and the swing arm. The thing of the structure which provided the buffer and the shock absorbing material in is known (patent document 1).
Furthermore, the lower end of the stabilizer extending from the stem of the upper part of the front fork is pivotally connected to the front end of the swing arm provided at the lower end of the front fork so that the front fork stem and the stabilizer can be connected to each other. There is also known a structure in which a spring is mounted on (Patent Document 2).

Japanese Utility Model Publication No. 62-17289 JP 05-69875 A

  However, in the above-described conventional buffer structure, the elastic member is arranged in a sliding pipe provided with a support pipe extending downward from the crown portion and a bearing of the front wheel, and the elastic member arranged in these elongated pipes. There is a drawback in that the capacity of the member may be strongly restricted, and it becomes difficult to secure a sufficient capacity of the elastic member to suitably absorb a strong impact force. In addition, two stopper mechanisms, a stopper mechanism for restricting excessive compressive deformation of the elastic member and a rebound stopper mechanism for preventing the sliding pipe from falling off from the support pipe, are incorporated in these pipes, respectively. Since there are many cases, the work of assembling the buffer mechanism into the front fork is not easy, and there is a drawback that the structure becomes complicated.

  In addition, in the other conventional buffer structure, a structure in which the elastic member is not incorporated in the pipe and the above disadvantage of the former is solved has been proposed. The same applies to the structures described in Documents 1 and 2. As a result, the assembly process is complicated, it takes time to install, the number of necessary parts is large, and the parts cost is increased, so that an improvement is necessary.

  Therefore, the present invention has been devised in view of the above points, and has a buffer structure that is relatively easy to assemble and relatively simple in construction without being strongly limited by the capacity of the elastic member, It is an object to provide an inexpensive front wheel cushioning structure for a bicycle.

In order to solve the above-mentioned problems, the present invention provides a pair of front fork blade portions joined to a front fork stem portion, the front fork blade portion being provided with an axle bearing supporting a front wheel axle at a lower end portion, and the fork of the front fork blade portion. A mudguard on the front wheel joined at or near the joint, and a mudguard stay connecting the mudguard and the axle bearing; and the front fork blade part is supported by a linear elastic member. The front fork blade portion, the mudguard, and the mudguard stay form a substantially triangular truss structure in a side view, wherein the front fork blade part, the mudguard, and the mudguard stay are connected to form a pipe and the axle bearing. This is a bicycle front wheel cushion structure.
According to the present invention, the blade portion of the front fork is composed of a support pipe, an elastic member, and a front wheel axle bearing, and is configured in a straight shape, so the front fork has a simple configuration and does not require parts such as a stopper mechanism. Therefore, the number of parts is reduced, the assembly process is simplified, and it is possible to provide a low-cost bicycle front wheel cushioning structure as a whole.
In addition, the front fork blade, mudguard, and mudguard stay form a substantially triangular truss structure, so that they can be moved laterally with respect to the elastic member not only when stopping or running at a constant speed, but also when braking and impacting. Since the load is reduced and a large amount of axial load is applied, it becomes possible to provide a rigid bicycle front wheel cushioning structure with increased rigidity against various overloads applied to the front wheel.

The elastic member may be a coil spring, and two bar members may be inserted into the coil spring from both ends of the coil spring, and the two bar members may be separated from each other at a central portion of the coil spring. .
According to this configuration, even when a lateral load is applied to the blade portion of the front fork while securing a shrinkage allowance, the deviation from the shaft center can be regulated.

The elastic member is an arch-shaped leaf spring, and both ends of the two arch-shaped leaf springs are rotatably coupled to each other and joined to the support pipe at the apex of the arch-shaped leaf spring, The arched leaf spring may be joined to the wheel bearing at the apex.
According to this configuration, even when a lateral load is applied to the blade portion of the front fork, the blade portion of the front fork that is strong against the lateral load can be provided.

The elastic member is a combination of a coil spring and a U-shaped leaf spring. Both ends of the coil spring are sandwiched between both ends of the U-shaped leaf spring, and the front fork blade portion is a support pipe in which the coil spring is linear. And the axle bearing may be connected to each other.
According to this configuration, the front fork blade can cope with a strong axial load or a large load applied to the blade portion of the front fork and is strong against a lateral load even when subjected to a lateral load. Can provide department.

  As described above, it is possible to provide a low-cost and strong bicycle front wheel cushioning structure.

The side view which showed 1st embodiment of this invention. The front view which showed 1st embodiment of this invention. The enlarged view which showed the blade part in 1st embodiment of this invention. The exploded view of the blade part in the first embodiment of the present invention. The enlarged view which showed the blade part in 2nd embodiment of this invention. (A) is a side view, (b) is a front view. The enlarged view which showed the blade part in 3rd embodiment of this invention. (A) is a side view, (b) is a front view.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a side view showing the first embodiment, and FIG. 2 is a front view thereof. FIG. 3 is an enlarged view showing the blade portion of the front fork, and FIG. 4 is a view showing components when the blade portion of the front fork is disassembled.
FIGS. 5 and 6 are enlarged views showing the blade portion of the front fork, particularly the elastic member, in the second embodiment and the third embodiment, respectively, (a) is a side view, and (b) ) Is a front view.
In these drawings, 1 is a bicycle, 10 is a front fork, 11 is a front fork blade part, 12 is a support pipe, 13 is an elastic member, 14 is a front wheel bearing, 15 is a front fork stem part, 16 is a crown part, and 20 is a crown part. Mudguard, 30 is a mudguard stay, 40 is a front wheel, 50 is a handle, 60 is a bicycle frame, 121 and 141 are receiving plates, and 122 and 142 are medium pipes.

  As shown in FIG. 1, the front fork 10 includes a front fork blade portion 11, a front fork stem portion 15, and a crown portion 16. The front fork blade portion 11 includes a linear support pipe 12, an elastic member 13 of a coil spring, and a front wheel. It consists of a bearing 14. The support pipe 12, the elastic member 13 of the coil spring, and the front wheel bearing 14 are connected so as to form a straight axis, and the front fork blade portion 11 is formed straight.

Further, the front fork blade portion 11, the mudguard 20 and the mudguard stay 30 form a substantially triangular truss structure in a side view.
Usually, the truss structure is a structure constructed on the basis of a triangle composed of straight members. Here, the substantially triangular truss structure includes a member that is not composed of a straight line in a part of the structural element. Specifically, it means including mudguards that are usually formed along the front wheels.
The front fork 10 is coupled to the bicycle frame 60 at the front fork stem portion 15 and connected to the handle 50, and is connected to the front wheel 40 at the front wheel bearing 14.

  As shown in FIG. 2, even when viewed from the front of the bicycle, the front fork blade portion 11 is formed straight by connecting the support pipe 12, the elastic member 13 of the coil spring, and the front wheel bearing 14. This is because when the front fork blade part 11 forms a straight axis, a bending moment hardly acts on the front fork blade part 11 and almost only axial force acts.

  As described above, the straight front fork blade part 11, the normal straight mudguard stay 30 and the mudguard 20 form a substantially triangular truss structure even when the shock is received through the front wheel 40 which has received a shock from the ground. This makes it possible to provide a strong bicycle front wheel cushioning structure.

  3, the crown portion 16 and the mudguard 20 are fixed by screwing, and the front fork blade portion 11 includes a support pipe 12 connected to the crown portion 16, a coil spring elastic member 13, and a front wheel. The mudguard stay 30 is connected to the front wheel 40 coaxially with the front wheel bearing 14 and is also fixed to the mudguard 20.

The fixed portions of the crown portion 16 and the mudguard 20 that are screwed become nodal portions in the truss structure, and the load is concentrated. Therefore, it is desirable to firmly fix the portions. Furthermore, in the screwing of the fixed portion, if a spring is attached between the nut and the fastening bracket or the crown portion (not shown), when the load is applied to this portion, the spring can absorb impacts and the like. More desirable. In addition, in FIG. 3, although this screw stop has stopped the screw from the front, it is not limited to this, You may stop from back or both.
Further, it is desirable that the fixed portions of the mudguard stay 30 and the mudguard 20 are similarly firmly fixed. The mudguard 20 receives a load from the mudguard stay 30 and generates a bending moment. However, the mudguard 20 has a substantially U-shaped cross section along the surface shape of the tire, so that the structure is strong against bending moment. It has become. However, in order to obtain a stronger truss structure, it is desirable to use a member having greater rigidity for the mudguard 20 itself.
It should be noted that the crown portion 16 does not use a lug-type crown as shown in the figure, but may be a shape (uni-crown type) in which the upper ends of the left and right fork blade portions are bent and joined to replace the crown. Needless to say. In such a case, the mudguard 20 and the vicinity of the joint portion of the pair of support pipes 12 can be fixed.

In FIG. 4, members constituting the front fork blade portion 11 and a method for forming the members are described in more detail. The straight support pipe 12 and the receiver 121, and the receiver 121 and the middle pipe 122 are joined together by welding, and all are coaxial. Although the cross section of the support pipe 12 is drawn as a quadrangle, other shapes such as other polygons, circles, and ellipses may be used. Similarly, the receiver 121 and the receiver 141 are also depicted as disk shapes, but may have other shapes as long as the elastic member 13 of the coil spring is received. The outer diameter of the middle pipe 122 may be smaller than the inner diameter of the elastic member 13 of the coil spring, and may have a size and a sectional shape that can be inserted therein. Further, it may be a solid bar instead of a pipe (hollow).
The middle pipes 122 and 142 are inserted into the elastic member 13 of the coil spring and reinforce rigidity against a lateral load applied to the elastic member 13 of the coil spring.

  Further, the front wheel bearing 14 and the receiver 141, and the receiver 141 and the middle pipe 142 are joined by welding. The receiver 141 and the middle pipe 142 are coaxial with each other. This is because the front fork blade portion 11 as a whole is coaxial. The receiver 121 and the receiver 141, and the middle pipe 122 and the middle pipe 142 preferably have the same shape and the same size. This is because the number of parts can be reduced.

A compression coil spring is used as the elastic member 13 of the coil spring, and the end surfaces of both ends thereof are polished so as to be in close contact with the seats of the receiver 121 and the receiver 141.
Also, assuming that a 60 kg person can withstand 5 times the weight, it is desirable that the outer diameter of the elastic member 13 of the coil spring is at least 25 millimeters (mm) and the wire diameter is at least 5 mm. . The number of turns of the coil is preferably about 8 turns. This is because if the number of windings is too large, it will bend laterally, and if it is too short, there will be no shrinkage allowance when subjected to an impact load. When the coil spring is used and mounted on a bicycle, the length of the coil spring at the time of reference load is about 65 mm. The length of each of the middle pipe 122 and the middle pipe 142 is preferably about one third of the length under the reference load in order to secure a shrinkage allowance. Note that the length of the support pipe 12 is appropriately adjusted according to the diameter of the front wheel 40.

  The front fork blade portion 11 has a middle pipe 122 and a middle pipe 142 inserted from both sides of the elastic member 13 of the coil spring, and the receiver 121 and the receiver 141 and both sides of the elastic member 13 of the coil spring are respectively connected by about three spots by spot welding. Are manufactured by being connected to each other. The coil spring may deteriorate in performance when heat is applied by welding or the like, but this is not the case with spot welding. In addition to spot welding, the catch 121 and the catch 141 can be provided with claws that are hooked by several coil springs, and through holes are provided on the side surfaces of the middle pipe 122 and the middle pipe 142 so that the outside of the coil spring can be removed. It is possible to fix by various methods so that the rods can be fixed by inserting a rod longer than the diameter into the through hole.

  FIG. 5 is an enlarged view of the elastic member in the second embodiment. In this embodiment, two arch-shaped leaf springs 13A1 and 13A2 are opposed to each other, and an elastic member 13A of a laminated leaf spring joined by a hinge 13A3 is used to rotatably couple both ends of each. The support pipe 12A is fixed to the top of the arch of the arch-shaped leaf spring 13A1, and the front wheel bearing 14A is fixed to the top of the arch of the arch-shaped leaf spring 13A2 by welding. The axis of the support pipe 12A and the axis of the front wheel bearing 14A are aligned. And a line connecting the hinges 13A3 at both ends and the axis are at right angles. With such a configuration, the support pipe 12A, the elastic member 13A of the leaf spring, and the front wheel bearing 14A are connected so as to form a straight axis, and the front fork blade portion is formed straight.

  Assuming that a 60 kg person can withstand 5 times the weight, the leaf springs 13A1 and 13A2 have a width of 25mm, a length of 120mm and a thickness of 3mm. The height of is preferably 40 mm.

  FIG. 6 is an enlarged view of the elastic member in the third embodiment. In the present embodiment, one elastic member is formed by combining the coil spring 13C and the U-shaped leaf spring 13B. As the coil spring 13C, a compression coil spring is used, and end surfaces of both ends thereof are polished so that U-shaped linear portions are in close contact with both ends of the U-shaped plate spring 13B which are parallel to each other. The length of the coil spring 13C and the inner diameter of both ends of the U-shaped plate spring 13B are the same, and the coil spring 13C is sandwiched between both ends of the U-shaped plate spring 13B, and both are coupled by welding (including spot welding).

  The support pipe 12A is disposed on one surface of the both ends of the U-shaped leaf spring 13B opposite to the surface in contact with the coil spring 13C, and the other surface of the both ends of the U-shaped leaf spring 13B is opposite to the surface in contact with the coil spring 13C. 14A, the front wheel bearing 14A is fixed, and the axis of the support pipe 12A, the axis of the front wheel bearing 14A, and the axis of the coil spring 13C are configured to be in a straight line. With such a configuration, the support pipe 12A, the coil spring 13C, and the front wheel bearing 14A are connected so as to form a straight axis, and the front fork blade portion is formed straight.

  Assuming that a 60 kg person can withstand 5 times the weight, the width of the U-shaped leaf spring 13B is 25 mm, the length of the coil spring 13C and the inner diameter of both ends of the U-shaped leaf spring 13B are 35 mm, The thickness of the U-shaped leaf spring 13B is desirably 3 mm. Further, it is desirable that the outer diameter of the coil spring 13C is at least 20 mm and the wire diameter is at least 4 mm. The number of turns of the coil is preferably about 4 turns. If the number of windings is too large, it can be said that the U-shaped leaf spring 13B has strengthened against lateral load, but the coil spring 13C will bend laterally, and if it is too short, there will be no shrinkage allowance when subjected to impact load. Because.

  Thus, the blade portion 11 of the front fork is composed of a linear support pipe that does not require a curve, an inexpensive coil spring or a leaf spring, the number of parts is small, the structure of the front fork is simple, and the manufacturing method is also Since it is simple, it is possible to provide a bicycle front wheel cushioning structure that is low in cost as a whole.

DESCRIPTION OF SYMBOLS 1 Bicycle 10 Front fork 11 Front fork blade part 12 Support pipe 121 Receptacle 122 Medium pipe 13 Elastic member (coil spring)
13A Elastic member (lap spring)
13A1 Elastic member (arched leaf spring)
13A2 Elastic member (arched leaf spring)
13A3 Hinge 13B Elastic member (U-shaped leaf spring)
13C Elastic member (coil spring)
14 Front wheel bearing 14A Front wheel bearing 141 Receptacle 142 Middle pipe 15 Front fork stem portion 16 Crown portion 20 Mudguard 30 Mudguard stay 40 Front wheel 50 Handle 60 Bicycle frame

Claims (4)

A pair of front fork blade portions each provided with an axle bearing supporting the front wheel axle at the lower end and joined to the front fork stem portion;
A mudguard of the front wheel joined at or near the joint of the fork stem part of the front fork blade part; and
A mudguard stay connecting the mudguard and the axle bearing;
The front fork blade portion is connected so that an elastic member is formed between a linear support pipe and the axle bearing,
The bicycle front wheel cushioning structure characterized in that the front fork blade portion, the mudguard and the mudguard stay form a substantially triangular truss structure in a side view. The elastic member is a coil spring;
The bicycle front wheel cushioning structure according to claim 1, wherein two bar members are inserted into the coil spring from both ends of the coil spring, and the two bar members are separated from each other at a central portion of the coil spring. . The elastic member is an arched leaf spring;
Both ends of the two arched leaf springs are rotatably coupled, joined to the support pipe at the apex of one of the arched leaf springs, and the wheel bearing at the apex of the other arched leaf spring The bicycle front wheel cushioning structure according to claim 1, wherein the bicycle front wheel cushioning structure is joined to the bicycle. The elastic member is a combination of a coil spring and a U-shaped leaf spring,
Both ends of the coil spring are sandwiched between both ends of the U-shaped leaf spring,
The bicycle front wheel cushioning structure according to claim 1, wherein the front fork blade portion is connected so that the coil spring is formed between a linear support pipe and the axle bearing.