JPH0790826B2 - Method for manufacturing bicycle drop handlebar made of carbon fiber reinforced plastic - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a carbon fiber reinforced plastic drop handlebar for a bicycle.

(Prior Art) A conventional bicycle drop handlebar manufacturing method includes:
There are a bending method using a roller shown in FIG. 7, a bending method using a time signature shown in FIGS. 8 and 9, and a bending method using a mandrel shown in FIGS.

The bending method using the time signature shown in Figs. 8 and 9 is that the material pipe (c) of the handlebar is inserted between the rollers (a) and (b) with two grooves, and the handle (d) is rolled. This is a method of rotating the material pipe (c) in the direction of the arrow around the rotation center axis (e) of (b) and bending the same material pipe (c) as shown by a dashed line.

In addition, in the bending method using the time signature shown in Figs. 8 and 9, the material pipe (c) of the handle bar is inserted between the grooved roller (b) and the grooved signature (f), and the handle ( d)
The method of rotating the roller (b) in the direction of the arrow around the rotation center axis (e) of the roller (b) to bend the same material pipe (c) has a higher roundness in the cross section of the pipe than the method of FIG. To be

The bending method using a mandrel shown in Figs. 10 and 11 is a bending method using a mandrel for increasing the roundness of the pipe cross section. (G) is suspended and supported by a pin (h). A flexible material mandrel, (c) is a material pipe of a handle bar fitted on the concentric mandrel (g), and the lower end of the mandrel (g) is formed into a spherical shape. The lower end is on the center line passing through the rotation center axis (e) of the roller (b). Further, the material pipe (c) is clamped by the clamp metal fitting (i), and the handle (d) is rotated in the direction of the arrow around the rotation center axis (e) to bend the material pipe (c). The material pipe (c) is bent without being deformed because it is at the tip of the cored bar (g) at its center.

(Problems to be Solved by the Invention) The method for manufacturing the drop handlebar for a bicycle shown in FIGS. 8, 8, 9 and 10 and 11 above is based on the material to be molded (material pipe (c)). If is made of metal and made of steel, the weight of the drop handlebar is heavy. Further, in the case of aluminum, there is a problem that high strength cannot be obtained.

The present invention is proposed in view of the above problems, and the object of the present invention is to improve workability. In addition, the finish of the product surface can be improved. Further, the strength of the central portion can be improved. It is an object to provide a method for manufacturing a carbon fiber reinforced plastic drop handlebar for a bicycle.

(Means for Solving the Problems) In order to achieve the above object, the method for producing a carbon fiber reinforced plastic drop handlebar for a bicycle according to the present invention is obtained by impregnating carbon fiber with a thermosetting resin. The prepreg thus obtained is wrapped around the flexible hollow rubber pipe in a laminated state, and then a rubber stopper is inserted into both end openings of the flexible hollow rubber pipe to seal the both end openings of the flexible hollow rubber pipe, Then, each rubber stopper is pierced with a pressure air injection needle to project the tip of each injection needle into the flexible hollow rubber pipe, and then the laminated prepreg and the drop handlebar molding upper metal on the left side. Preheat the mold and lower mold,
Next, the laminated prepreg and the flexible hollow rubber pipe are bent along the molding recess of the lower mold and set in the molding recess, and then the upper mold is superposed on the lower mold. Secure each other and then inject pressurized air from each of the needles into the flexible hollow rubber pipe,
The flexible hollow rubber pipe is inflated, and the laminated prepreg is pressed by the internal pressure into the molding recesses of the lower mold and the upper mold to shape it, and then each of the injection needles is pulled out from the rubber stopper and injected. The needle removal mark is closed by the elasticity of the rubber stopper, and then the lower mold and the upper mold are heated to the curing temperature of the thermosetting resin to cure the laminated prepreg, and the left drop handlebar is Mold, then release the lower mold and the upper mold, take out the left drop handle bar from the lower mold, cut both ends of it, and manufacture the left drop handle bar. Then, the right drop handle bar is manufactured through the same manufacturing process as the left drop handle bar, and these left and right drop handle bars are butted, and the inner surface of the butted end part is used for engagement. Insert the tubes and Together adhesively fixed with an adhesive bonding surface of the handle post mounting outer tube to the outer surface of the butt end and fitted on, it is characterized in that it has adhered and fixed by an adhesive bonding surfaces to each other.

(Operation) As described above, the method of manufacturing the drop handlebar for a bicycle made of carbon fiber reinforced plastic according to the present invention includes a prepreg obtained by impregnating carbon fiber with a thermosetting resin around a flexible hollow rubber pipe. Wrap in a laminated state, then insert rubber stoppers into the openings at both ends of the flexible hollow rubber pipe to seal the openings at both ends of the flexible hollow rubber pipe, and then inject the compressed air into each rubber stopper. And project the tip of each injection needle into the flexible hollow rubber pipe, and then preheat the laminated prepreg and the upper mold and the lower mold for molding the drop handlebar on the left side, and then The laminated prepreg and the flexible hollow rubber pipe are bent along the molding recess of the lower mold and set in the molding recess, and then the upper mold is overlaid on the lower mold to form one another. Fixed Then, pressurized air is injected into the flexible hollow rubber pipe from each of the injection needles to expand the flexible hollow rubber pipe, and the laminated prepreg is molded by the internal pressure into the lower mold and the upper mold. After shaping by pressing into the concave portion, each of the injection needles is pulled out from the rubber stopper, the trace of the injection needle is closed by the elasticity of the rubber stopper, and then the lower mold and the upper mold are thermoset resin. Heated to the curing temperature of
The laminated prepreg is cured to form the left drop handle bar, then the lower mold and the upper mold are released, and the left drop handle bar is taken out from the lower mold. Cut both ends to make the left drop handlebar, and then make the right drop handlebar through the same manufacturing process as the left drop handlebar. Butt the handlebars together,
Insert the inner cylinder for engagement into the inner surface of the abutting end, and bond and fix the joint surfaces of each other with an adhesive, and fit the outer cylinder of the handle post on the outer surface of the abutting end for mutual engagement. The joining surface is bonded and fixed with an adhesive to manufacture a carbon fiber reinforced plastic bicycle drop handlebar having an arbitrary width.

(Example) Next, a method for manufacturing a carbon fiber reinforced plastic drop handlebar for bicycle according to the present invention will be described with reference to an example shown in Figs. 1 to 6, and Figs. 1) is the left drop handle bar, (2) is the right drop handle bar, (3) is the handle post mounting outer cylinder, (4)
Is an inner cylinder for joining, (5) is an adhesive, (6) in FIGS. 1 and 2 is a lower mold for forming the drop handlebar on the left side, and (7) is an upper mold for forming the handlebar on the left side. Mold, (8) bolts for fixing upper and lower molds, (9) rubber plug retaining metal fitting mounting hole, (1
0) is a flexible pipe (silicon rubber flexible pipe),
(11) prepreg obtained by impregnating carbon fiber with thermosetting resin, (12) rubber stopper, (13) flexible pipe stopper, (14) rubber stopper stopper, (15) Is a fixing bolt for fixing the rubber stopper removal stopper (14) and the lower die (6), and (16) is a fixing bolt for fixing the rubber stopper stopper (14) and the upper die, (17) ) Is a needle for injecting pressurized air.

In manufacturing a carbon fiber reinforced plastic drop handlebar for bicycles, a prepreg (11) obtained by impregnating carbon fiber with a thermosetting resin is laminated around a flexible hollow pipe (10). Then, the rubber hollow plug (12) is inserted into the openings of both ends of the flexible hollow pipe (10) to seal the flexible hollow pipe (10), and then the rubber hollow plug (12) is pressed. Insert the injection needle (17) for air injection,
The tip of the injection needle (17) is projected into the flexible hollow pipe (10), and then the laminated prepreg (11) and the left drop handlebar molding upper mold (7) and lower mold are formed. (6) is preheated at 80 ° C. for about 1 hour, and then the same laminated prepreg (11) and flexible hollow pipe (10) are set in the molding recess (6a) of the lower mold (6), The upper mold (7) is overlaid, the upper and lower molds (7) (6) are fixed with bolts (8), and then pressurized air is injected from the injection needle (17) into the flexible pipe (10), Same flexible pipe (10)
Is inflated to press the laminated prepreg (11) into the molding recesses (6a) (7a) of the lower mold (6) and the upper mold (7), and then the injection needle (17) is attached to the rubber stopper ( 12), pull out the injection needle (17) with the elastic force of the rubber stopper (12),
Then, the lower mold (6) and the upper mold (7) are heated at a curing temperature of the thermosetting resin of 130 ° C. for about 2 hours to cure the laminated prepreg (11), and the left handlebar bar ( 1) is molded, then the upper mold (7) is released from the lower mold (6), the left drop handlebar (1) is taken out from the lower mold, and the flexible pipe (10) After pulling out from the inside of the left drop handlebar (1), both ends of the left drop handlebar (1) are cut to manufacture the left drop handlebar. Further, the right drop handle bar (2) is manufactured through the same process as the left drop handle bar (1), and these left and right drop handle bars (1) and (2) are butted. The inner cylinder (4) for joining is inserted into the inner surface of the butt end, the joint surface is adhered and fixed with an adhesive (5), and the outer cylinder (3) for mounting the handle post is attached to the outer surface of the butt end. Fit,
The joint surface is adhered and fixed with an adhesive (5) to manufacture a carbon fiber reinforced plastic drop handlebar for bicycles of arbitrary width.

As shown in Table 1 below, the carbon fiber reinforced plastic has a tensile elastic modulus (GPa) of 122 compared with 207 of carbon steel.
Although it is small at about 60%, compared with 72.6 of aluminum alloy
122, about 70% larger. In addition, the tensile strength (MPa) is 1360 for 510 of carbon steel and 466 of aluminum alloy, which is 2-3 times as large as that of carbon steel and aluminum alloy. Further, the specific elastic modulus (tensile elastic modulus divided by density) and the specific strength number (tensile strength divided by density) are also larger than those of carbon steel and aluminum alloy. The density (g / cm ³ ) is about 1/5 that of carbon steel and about 1/2 that of aluminum alloy. This means that the carbon fiber reinforced plastic is light and strong. The strength of the carbon fiber reinforced plastic shown in Table 1 is obtained by arranging the fibers in a fixed direction, and the strength value is a value when the fibers are pulled in the direction of the arranged fibers. Generally, metal shows the same strength even if it is pulled in the longitudinal and transverse directions, and is called an isotropic material. However, in the case of fiber, the longitudinal strength is large and the transverse strength is small, and We call it sex material. When using materials with such characteristics for bicycle parts, sufficient consideration must be given to bending, twisting, and whip (lateral force). Therefore, the fiber direction is 0 ° C, ± 45
Since it is formed by arranging at an angle of 90 ° and suitable for parts,
The carbon fiber reinforced plastic drop handlebar has high strength and is lightweight. In addition, the carbon fiber reinforced plastic drop handlebar has the great advantage that it does not corrode.

The carbon fiber reinforced plastic consists of carbon fiber and epoxy resin, and the fiber volume content is 60%.

(Effects of the Invention) The carbon fiber reinforced plastic drop handlebar bicycle manufacturing method of the present invention is configured as described above, and the following effects are achieved. That is, (i) the flexible hollow rubber pipe is initially linear.
Since the prepreg can be wound around the flexible hollow rubber pipe in a laminated state, workability can be improved.

(Ii) Also, insert rubber stoppers into the openings of both ends of the flexible hollow rubber pipe to seal the openings of both ends of the flexible hollow rubber pipe, and then pierce the rubber stoppers with injection needles for injecting pressurized air. Then, the tip of each injection needle is projected into the flexible hollow rubber pipe, and then the laminated prepreg and the left drop handlebar molding upper mold and lower mold are preheated,
Next, the laminated prepreg and the flexible hollow rubber pipe are bent along the molding recess of the lower mold and set in the molding recess, and then the upper mold is superposed on the lower mold. Secure each other and then inject pressurized air from each of the needles into the flexible hollow rubber pipe,
Since the flexible hollow rubber pipe is expanded and the laminated prepreg is pressed against the molding concave portion by the internal pressure at this time to shape the product, the finished product surface can be improved.

(Iii) Initially, the prepreg is initially wound around the linear flexible hollow rubber pipe in a laminated state, and then the laminated prepreg and the flexible hollow rubber pipe are bent along the concave portion for molding of the lower mold. Set in the recess for molding,
Next, the upper mold is overlaid on the lower mold to fix each other, and then pressurized air is injected from each injection needle into the flexible hollow rubber pipe to expand the flexible hollow rubber pipe, and the internal pressure at this time is expanded. (10 ~ 13 kg / cm ² ) After shaping the laminated prepreg by pressing it into the molding recess, heat the lower mold and the upper mold to the curing temperature of the thermosetting resin to cure the laminated prepreg, Mold the left drop handlebar, then release the lower mold and upper mold, take out the left drop handlebar from the lower mold, cut both ends of it, and remove the left mold. The left handlebar is manufactured, and the right handlebar is manufactured through the same manufacturing process as the left handlebar, and the left and right handlebars are butted to each other. Insert the inner cylinder for engagement into the inner surface of The joint surface of the mat is fixed with an adhesive, and the outer cylinder for mounting the handle post is fitted on the outer side of the butted end so that the joint surface of each is fixed with an adhesive. In addition to the fact that it is possible to laminate a prepreg with a large thickness in such a part, particularly in the central part (handle post fixing part),
The inner cylinder for engagement and the outer cylinder for mounting the handle post can improve the strength of the central portion.

[Brief description of drawings]

FIG. 1 is a perspective view showing a releasing state of a lower mold and an upper mold for forming a drop handlebar on the left side, which are used for carrying out the method for manufacturing a drop handlebar for a carbon fiber reinforced plastic bicycle according to the present invention. 2 and 3 are perspective views showing the joined state of the lower die and the upper die, FIG. 3 is a vertical sectional side view showing the piercing state of a pressure air injecting needle, and FIG. 4 is a left side slot. Fig. 5 is a perspective view of the handlebar, Fig. 5 is a perspective view showing the joined state of the left and right drop handlebars, Fig. 6 is a vertical sectional front view showing the joined state, and Fig. 7 is a conventional bending method using rollers. FIG. 8 is a side view showing a conventional bending method using a time signature, FIG. 9 is a front view thereof, FIG. 10 is a side view showing a conventional bending method using a mandrel, and FIG. It is the top view. (1) ... left drop handlebar, (2) ... right drop handlebar, (3) ... handle post mounting outer cylinder, (4) ... joining inner cylinder, (5 ) ... Adhesive, (6) ... Lower mold for forming drop handlebar on the left side, (7) ... Upper mold for forming drop handlebar on the left side, (8) ... Upper and lower molds Fixing bolt, (9) …… Rubber retaining metal fitting hole, (10) …… Flexible hollow rubber pipe (silicon rubber flexible hollow rubber pipe), (11) …… Carbon fiber impregnated with thermosetting resin Prepreg obtained by
(12) …… Rubber stopper, (13) …… Flexible pipe stopper,
(14) …… Rubber plug retaining metal fittings, (15) (16) …… Fixing bolts, (17) …… Injection needle for pressurized air injection.

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Claims (1)

[Claims] 1. A prepreg obtained by impregnating a carbon fiber with a thermosetting resin is wound around a flexible hollow rubber pipe in a laminated state, and then a rubber plug is inserted into both end openings of the flexible hollow rubber pipe. Then, the openings at both ends of the flexible hollow rubber pipe are sealed, and then the respective rubber stoppers are pierced with the injection needles for injecting pressurized air, so that the tips of the respective injection needles are projected into the flexible hollow rubber pipe. Then, preheat the laminated prepreg and the upper mold and lower mold for molding the drop handlebar on the left side, and then apply the laminated prepreg and the flexible hollow rubber pipe along the concave portion for molding of the lower mold. And bend it to set in the same molding recess, then stack the upper mold on the lower mold and fix each other, and then inject pressurized air into the flexible hollow rubber pipe from each injection needle. And flexible The empty rubber pipe is expanded, and the laminated prepreg is pressed against the molding recesses of the lower mold and the upper mold by internal pressure to shape it, and then each of the injection needles is pulled out from the rubber plug, and the trace of the injection needle is removed. Is closed by the elasticity of the rubber stopper, then the lower mold and the upper mold are heated to the curing temperature of the thermosetting resin to cure the laminated prepreg to mold the left handlebar bar, Release the above lower mold and the above upper mold, take out the left drop handle bar from the lower mold, cut both ends of it, and manufacture the left drop handle bar. The drop handlebars on the right side are manufactured through the same manufacturing process as the drop handlebars of, and the left and right drop handlebars are butted, and the inner cylinder for engagement is inserted into the inner surface of the butted ends. Join each other The carbon fiber reinforced plastic bicycle is characterized in that the handle post is attached and fixed by an adhesive, the handle post mounting outer cylinder is fitted on the outer surface of the butt end, and the joint surfaces of the handle post are attached and fixed by the adhesive. For manufacturing drop handlebars for automobiles.