JPH0662106B2 - Method for manufacturing front bicycle fork made of carbon fiber composite - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a front fork for a bicycle, which utilizes a carbon fiber composite.

(Prior Art) Utilizing a sheet winding technique that uses a carbon fiber composite sheet material and winds this with a mandrel as a mandrel to form it, and it has a predetermined length and both ends are tapered. Make a tubular material that has a certain length, and place 90 points in the same direction and in the same plane at two points at regular intervals in the center of the tubular material.
It is bent back and forth to make a U-shaped pipe with two pipe legs, the central part of which is the crown of the front fork, and the legs are the pods. That is, Japanese Patent Publication No. 58-933 discloses a method of making a crownless front fork in which a crown and both pods are integrated so that the crown becomes unnecessary. The pipe material disclosed herein is a steel pipe, and, of course, its strength or rigidity is different from that of the carbon fiber composite pipe material.

(Problems to be Solved by the Invention) Since the front fork of the bicycle is directly related to the handle of the bicycle, the front fork of the bicycle must sufficiently withstand the operation of the handle.

The present invention provides a method for mounting a metal reinforcement inside a front fork made of a carbon fiber composite (hereinafter a composite will be omitted) in order to exhibit a strength sufficiently comparable to that of a steel front fork. It is a thing.

(Means for Solving the Problems) The present invention is to form a pipe material having a predetermined length and tapered at both ends, using a composite made of carbon fiber and a thermosetting resin as a raw material, and forming the pipe material in the center of the pipe material. A U-shaped pipe material having two pipe legs is formed by bending each at 90 degrees in the same direction on the same plane at two locations with a certain distance, and a stem receiving port and a stem are formed in the center of the U-shaped pipe material. Cut out a long hole that connects to the left and right of the receiving port and reaches the vicinity of the shoulder of the U-shaped pipe material, and then has two U-shaped crown legs in advance and use it for the stem receiving port of the U-shaped pipe material. Fix the stem in the cylindrical hole of the metal reinforcement provided with the fitting cylinder,
A metal reinforcement with a stem is inserted into the U-shaped pipe through the stem receiving port and a long hole connected to the stem receiving port, and the U-shaped pipe is installed in the pipe. Then, the long hole is wrapped with carbon fiber composite tape to be closed and then formed. The pipe material with the metal reinforcement attached is set in a split mold, and air is blown from the opening end of the pipe leg of the pipe material to adjust the shape, and at the same time, heat the mold to heat the thermosetting resin. And the metal reinforcing member and the pipe member are fixed to each other for reinforcement, the mold is opened, the pipe member is taken out, and a metal claw to be preformed is fixed to the end of the pipe leg. A method of manufacturing a front fork for a bicycle, which is made of a carbon fiber composite equipped with a metal reinforcement.

Here, the carbon fiber composite will be briefly described below from known materials.

Align long fibers of carbon fibers in one direction, impregnate this with a thermosetting epoxy resin as a matrix resin,
Make a semi-cured sheet. This is called a prepreg, and the thickness of one prepreg is 0.1 to 0.4 mm, and a plurality of these prepregs are laminated to have a wall thickness of about 2 mm.

Generally, the length of the front fork for adults is about 40 cm,
If the length of the crown portion is about 10 cm, the required length is about 90 cm in total, so a carbon fiber tube material having a length of about 90 cm is first formed. Since both ends of the pipe material are tapered, the outside diameter of the pipe material is 2 except for the tapered portion.
2mm

(Example) A method for forming a carbon fiber pipe material is based on a known technique, and a method for forming a pipe material with tapered ends is also included in the known technique. In the present invention, the required carbon fiber pipe material is attached as attached. The drawings will be described.

FIG. 1 shows the required carbon fiber tubing 1 with both ends tapered 2
a and 3a.

Regarding the carbon fiber tubing 1 having a length of about 90 cm shown in FIG. 1, the tubing 1 is bent in the same direction on the same plane at an angle of about 90 degrees from two points at both ends having a center length of about 10 cm. It is molded into a U shape.

FIG. 2 shows a U-shaped pipe material, in which the pipe legs 2 and 3 have tapered ends 2a and 3a, respectively, and show the crown portion 4.

In FIG. 3, a circular through hole 5 for holding a stem 9 (FIG. 7) is installed in the center of a crown 4 of a U-shaped pipe material, and long holes 6, 7 connecting to the left and right of this through hole 5 are cut out. The through hole 5 and the elongated holes 6 and 7 form a reinforcing member 8 which is integrated by inserting and fixing a stem 9 into a central opening 8a of a metal reinforcing member 8 (FIG. 4) of the present invention described later. It is an incision for insertion and attachment inside the carbon fiber tube.

The reason why the metal reinforcement 8 is fitted inside the carbon fiber tubing is to reinforce the original high elasticity when the carbon fiber tubing is used as a crownless front fork, and the front wheel of the bicycle can be freely moved left and right. This is to reinforce the front fork so that it does not cause any anxiety about the strength and rigidity of the front fork.

That is, the front fork material without forming a crown on the shoulder is considered to be unsatisfactory in the strength of the shoulder, and a strengthening method against the crown is taken. However, according to the present invention, the metal reinforcement described below is used. As a result, a crownless front fork material having excellent strength can be obtained.

FIG. 4 is a perspective view showing the metal reinforcing tool 8 of the present invention, which is made of a steel plate having a thickness of 1 to 2 mm and has a U-shaped cross section as shown in FIG. As shown in the figure, a crown material is provided with two legs 8d and 8e having a U-shaped cross section from both ends of the crown-shaped upper portion. Two circular notches (represented by one 8f) are provided on the right and left crowns 8b and 8c, respectively, and two legs 8d and 8e are provided with four circular notches 8f, respectively. However, the number of notches 8f is not limited.

These circular notches 8f are for making the reinforcing tool 8 adhere well to the carbon fiber tube material, for facilitating the impregnation of the impregnated thermosetting resin, and for making the reinforcing tool 8 lighter.

The lower end of the stem 9 is inserted and fixed through the cylindrical hole 8a in the upper part of the reinforcing member 8.

Incidentally, FIG. 5 is a view of the reinforcing tool 8 as seen from above, FIG. 6 is a front view of one leg 8e of the reinforcing tool 8, and FIG. 11 includes a circular notch 8f of the reinforcing tool 8. A U-shaped cross section is shown.

Needless to say, the reinforcing member 8 is made so as to be able to closely adhere to the inside of the crown 4 of the front fork formed of carbon fiber and both legs 2 and 3 connected thereto. Further, the crown 4 has been described as a U-shaped pipe material integrally molded, but it is also possible to prepare a pipe leg in advance and assemble and mold this into a crown.

As described above, the reinforcing member 8 and the stem 9 are attached and fixed to each other as shown in FIG. 8. The stem mounting reinforcing member has the through hole 5 shown in FIG. , 7
Then, the carbon fiber tube is inserted into and attached to the carbon fiber tube, and then the tape or sheet made of carbon fiber composite material is wound around these slots 6 and 7 to seal the slots 6 and 7.

Needless to say, the stem 9 is also made of metal, and the ring 10 in FIG. 9 is installed on the stem 9 as a lower ball receiver. In FIG. 10, the cross section of the reinforcing member 8 in AA in FIG. It shows a character shape and also shows a circular notch 8f.

As described above, the front fork material 12 (Fig. 11) formed by inserting and installing the reinforcement device 11 with a stem inside the crown 4 of the U-shaped carbon fiber tube and both legs 2, 3 is shown in Fig. 12 next. Insert and set in the split mold 13 shown. FIG. 12 is a conceptual diagram, the front fork material 12 is also illustrated more simply than that shown in FIG. 11, and the mold 13 is composed of an upper mold and a lower mold. In FIG. Show.

The auxiliary equipment of the mold 13 is also omitted.

The front fork material 12 is set in the lower mold of the mold 13, the upper mold is installed, and the mold 13 is heated (the heating device is not shown), and at the same time, compressed air is blown from the openings of both tapered pipe ends as shown by arrows. (The air blowing device is not shown), and the shape of the carbon fiber tube is adjusted by blowing air. At this time, the thermosetting resin impregnated in the carbon fiber composite is cured by heating, and the metal reinforcing member 8 is fixed to the carbon fiber together with the metal reinforcing member 8 and the resin impregnated through the plurality of circular notches 8f further strengthens the reinforcing member 8. It is considered that the same effect is exerted on the back surface of the.

When the processing in the mold is completed, the mold is opened, the front fork material 12 is taken out, and the claws (not shown) which can be preformed by any known technique are fixed to both tapered pipe ends. A finished front fork for a bicycle is obtained, which consists of a carbon fiber composite with reinforcements.

(Effects of the Invention) By the method of the present invention, a required pipe material is molded from a carbon fiber material, and a crownless front fork in which a crown is integrated from the pipe material is formed to further reinforce the carbon fiber material for further practical use. The crownless front fork of the present invention, which is equipped with a metal reinforcing member inside thereof, is to obtain a bicycle part that is much lighter and stronger than the conventional metal fork. .

[Brief description of drawings]

FIG. 1 is a perspective view of a pipe material molded from a carbon fiber composite, FIG. 2 is an explanatory view of a front fork material of the present invention formed by bending the pipe material into a U shape, and FIG. 3 is a plan view of the front fork material, 4 to 6 are perspective views of the metallic reinforcing tool of the present invention, a view from above, and a side view, FIG. 7 is a perspective view of the stem, and FIG. 8 is a cross-sectional view in which the stem is attached to the reinforcing tool. FIG. 9 is a perspective view of a ring-shaped lower ball receiver installed on the stem, FIG. 10 is a sectional view taken along line AA of FIG. 8, and FIG. 11 is a front fork material of the present invention in which a reinforcing tool is inserted and installed in a pipe material. FIG. 12 is a cross-sectional view of the upper portion, and FIG. 12 is a plan view of a metal fitting into which the front fork material of FIG. 11 is inserted and processed. 1 ... Tubular material composed of carbon fiber composite material 2 ... U-shaped tubular material, 5 ... Circular through-hole 6,7 ... Long hole, 8 ... Metal reinforcement 8a ... Cylindrical hole, 8f ... Circular notch 9 …… Stem 10 …… Lower ball receiving ring 11 …… Reinforcement tool with stem 12 …… Front fork material that can be loaded with reinforcement tool 13 …… Mold for processing front fork material

Claims (1)

[Claims] 1. A pipe material having a predetermined length and tapered ends at both ends is formed from a composite material of carbon fiber and a thermosetting resin, and the pipe material is provided at two places at a certain distance from the center of the pipe material. A U-shaped pipe member having two pipe legs is formed by bending each in the same direction by 90 degrees in the same plane, and a stem socket is connected to the center of the U-shaped pipe member and connected to the left and right of the stem socket. A metal with a long hole that reaches the vicinity of the shoulder of the U-shaped pipe material is incised, and then has a U-shaped two crown-shaped legs and is provided with a cylinder that fits into the stem socket of the U-shaped pipe material. The stem is fixed to the cylindrical hole of the reinforcing tool, and the metal reinforcing tool with a stem is inserted into the U-shaped pipe through the stem receiving hole and the long hole connected to the stem receiving hole, and the metal reinforcing tool with the stem is installed in the tubular material. Wrap and close with composite tapes, and then set the pipe material with the metal reinforcement attached that is to be molded in a split mold, The air is blown from the open end of the pipe leg for shaping and adjustment, and at the same time, the mold is heated to cure the thermosetting resin and the metal reinforcing member and the pipe material are fixed and reinforced. Open the mold and take out the pipe,
A method for manufacturing a front fork for a bicycle, comprising a carbon fiber composite with a metal reinforcing member, characterized in that a metal claw that can be formed in advance is fixed to the end of the pipe leg.