JPH09268U - Bicycle frame joint structure - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To improve an adhesive joint between a joint of a bicycle frame body and a pipe. SOLUTION: In a joint structure of a bicycle frame body in which a pipe is fitted to a cylindrical body-attached portion protruding from a joint and is joined by adhesion, the fitting position of the pipe is determined on the joint side. A step portion is formed to be brought into contact with the end surface of the pipe, and a male and female fitting surface having the same diameter is provided on both members facing the joint circumferential line on the outer surface side of the joint and the pipe, and further connected to this fitting surface. A structure for joining bicycle frames in which a taper surface that can be fitted is formed, and the taper surface facing each other when fitted is sealed with an adhesive layer. DESCRIPTION OF SYMBOLS 1 ... Upper pipe, 1a ... Internal same diameter cylindrical part, 1b ... Internal tapered cylindrical part, 6 ... Head lug, 6a ... Body part, 6b ... Step part, 6c ... External same diameter cylindrical part, 6d ... External tapered cylindrical part, A: Male-female mating surface, B:
Opposed taper surface, L ... Outer surface side joint circumference line.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to improvement of adhesive bonding between a joint and a pipe in a bicycle frame body.

[0002]

[Prior art]

 In recent years, pipes made of light metal (aluminum, titanium, etc.), FRP (fiber reinforced plastic), FRM (fiber reinforced metal), etc. have been drawing attention for the purpose of reducing the weight of bicycle frame bodies. However, these new material pipes cannot be joined by welding or brazing like conventional iron pipes. Therefore, in order to adopt these pipes in the frame body of a bicycle, there is a strong demand for improvement in joining technology by adhesion. As shown in FIG. 5, the bicycle frame body includes an upper pipe 1, a lower pipe 2, a standing pipe 3, a back hawk 4, various thin pipes such as a chain stay 5, a head lug 6, a hanger lug 7, a seat lug 8 and a rear pawl 9. It is constructed by joining various joints.

An example of conventional joining is one in which a stepped portion and a tapered cylindrical portion are simply formed on the outer periphery of a body portion of a head lug, as described in Japanese Utility Model Laid-Open No. 57-8191. An adhesive was applied to the upper pipe to fix it. As a further improvement of this, as shown in FIG. 6, a stepped portion 6b and an outer tapered cylindrical portion 6c are formed on the outer circumference of the body portion 6a of the head lug 6, and an inner tapered cylindrical portion 1a is formed at the front end of the upper pipe 1. After forming and applying an adhesive material to both taper portions, the upper pipe 1 is fitted to the body portion 6a, and the end surface of the upper pipe 1 is brought into contact with the step portion 6b for positioning. At that time, a predetermined gap was secured due to the difference in diameter between the opposite tapered portions, and this gap was used as an adhesive layer. When the adhesive was cured, the pipes and joints shown in Fig. 5 were fitted together at the same time to be assembled into a frame body, and the whole body was heated while maintaining its shape.

[0004]

[Problems to be solved by the device]

 However, in the above-described adhesive joining method, since the end face of the upper pipe 1 is brought into contact with the step portion 6b of the head lug 6 to be positioned at the time of fitting, there is originally no gap in the pipe end face, that is, the seam circumferential line L on the outer surface side. It should not be possible, but it is inevitable that some gap will be created due to dimensional error in pipe length or assembly error.

Since the adhesive material 10 filled in the gaps between the tapered portions expands when heated, a part of the adhesive material protrudes outside from the gaps, that is, the outer circumferential seam circumferential line L, and is cured as it is. It often happened. Therefore, it is necessary to work to remove the adhesive material 11 protruding from the seam circumference line L in appearance, but it is extremely troublesome to remove only the protruding portion so as not to damage the surface of the pipe or the joint. It was work. Moreover, as shown in FIG. 5, there are many joints in one frame body, so that the number of man-hours is large and the mass productivity is insufficient.

[0006]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention employs the following solution. That is, in a joint structure of a bicycle frame body in which a pipe is fitted to a cylindrical body portion protruding from a joint and joined by adhesion, the pipe for determining the fitting position of the pipe on the joint side. A step portion that contacts the end surface of the joint, and a male and female fitting surface of the same diameter is provided on both members facing the joint circumferential line on the outer surface side of the joint and the pipe. It is characterized in that a taper surface which can be fitted is formed, and the taper surface which faces at the time of fitting is sealed with an adhesive layer.

[0007]

[Embodiment of the invention]

 Since the present invention is constructed as described above, the adhesive does not protrude from the joint circumferential line on the outer surface side of the joint and the pipe. That is, since the fitting surfaces of both members facing the outer circumferential side seam circumferential line are male and female fitting surfaces of the same diameter, the adhesive can be prevented from protruding.

Here, the same diameter means that the gap between the male and female fitting surfaces of the joint and the pipe is about 0 to 0, 3 mm. A minus clearance means that the diameter is larger on the male side when fitting, which makes fitting by hand difficult, and if it is 0 or 3 mm or more, the sealing effect decreases. More preferably, the gap is 0 to 0, 1 mm.

Then, by setting the widths of the fitting surfaces to be equal to or larger than the dimensional error and the assembly error of the expected pipe length, it is possible to prevent a gap from being created due to these axial errors. is there. The width of the fitting surface is arbitrary, but about 3 mm is sufficient.

Further, the tapered surfaces formed on both members in a continuous manner with the fitting surface have a function of uniformly stretching while pressing the adhesive material applied thereto at the time of fitting, and the gap between the tapered surfaces is Filled with an adhesive layer.

Generally, there are many kinds of adhesives, but for bonding a bicycle frame body, a liquid thermosetting adhesive having excellent bonding strength, bonding durability, and workability is most suitable. Here, the "liquid thermosetting type" means that it is heated to about 120 ° C and cured in about 1 hour.

According to the present invention, with the above-described structure, the adhesive is completely sealed at the time of joining, and the adhesive does not squeeze out from the joint circumferential line on the outer surface side.

[0013]

【Example】

 Hereinafter, embodiments of the present invention will be described with reference to the drawings, focusing on the joining of the head lug and the upper pipe. (Example 1) FIG. 1 is a main part sectional view of a head lug 6 and an upper pipe 1, and FIG. 2 is a partial sectional view showing a fitted state of both members. The head lug 6 is provided with a cylindrical body portion 6a having a diameter substantially equal to the outer diameter of the upper pipe 1, which will be described later. A step portion 6b is formed on the body-attached portion 6a and has a step corresponding to the wall thickness of the end surface of the upper pipe 1.

The step 6b forms an outer surface side seam circumferential line L with the upper pipe 1, and the step 6b is formed with an outer cylindrical portion 6c having the same diameter. It serves as a male-female fitting surface A with the pipe 1. It is sufficient that the width of the outer cylindrical portion 6c having the same diameter is about 3 mm. Further, an outer taper cylindrical portion 6d is formed continuously with the outer same diameter cylindrical portion 6c, the outer diameter of which decreases toward the end.

On the other hand, the upper pipe 1 forms an outer surface side seam circumferential line L together with the stepped portion 6b. An inner same diameter cylindrical portion 1a having a width of about 3 mm is formed on the inner surface of the end portion, and the upper pipe 1 1, an inner tapered cylindrical portion 1b is formed whose inner diameter decreases toward the inside. The end of the taper section is the inner diameter of the original pipe. Here, the outer same-diameter cylindrical portion 6c of the body portion 6a and the inner same-diameter cylindrical portion 1a of the upper pipe 1 have the same diameter, and these are fitted to each other to form a male-female fitting surface A. Will be formed.

Further, the outer taper cylindrical portion 6d and the inner taper cylindrical portion 1b can be fitted with substantially the same gradient, and these taper surfaces that are continuous with the male and female fitting surface A and face each other. It forms B.

In order to bond the head lug 6 and the upper pipe 1, an adhesive is applied to the surfaces of the tapered cylindrical portions 6d and 1b of the head lug 6 and the upper pipe 1, and the two members are fitted together. . At this time, first, the adhesive material sandwiched between the two tapered cylindrical portions is pressed and uniformly thinly stretched as the gap between the tapers becomes narrower. In this way, the end portion of the outer same diameter cylindrical portion 6c of the head lug 6 and the end portion of the inner same diameter cylindrical portion 1a of the upper pipe 1 become close to a contact state, and the end portion of the upper pipe 1 is further pressed and fitted. Is abutted against the step 6a of the head lug 6 for positioning. An outer surface side seam peripheral line L is formed here between the upper pipe 1 and the stepped portion 6a of the body portion 6.

At that time, a predetermined gap is formed due to the difference in diameter between the taper portions facing each other, and this becomes the thickness of the adhesive layer. Then, at this time, the excess adhesive is squeezed out to the outer circumferential line L of the upper pipe 1 and the inner side of the upper pipe 1. The same work is performed on the hanger lug 7, the sheet lug 8 and the rear claw 9 to assemble them as a frame body, wipe off the adhesive material protruding from the outer surface side seam peripheral line L, and then heat cure it.

Even if the adhesive material expands or the fluidity increases during the heat curing, since the fitting surface A having the same diameter is formed by these both members, a dimensional error and an assembly error may occur. However, no radial gap is formed between the two members, so that the adhesive does not extend from the inner portion along the outer surface side seam circumferential line L.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 also shows a cross section of the joint between the head lug 6 and the upper pipe 1. The head lug 6 has a cylindrical shape and is larger in diameter than the upper pipe 1 and has a shorter axial length in the outer trunk portion 6e and an inner body which is concentric therewith and has a smaller diameter than the upper pipe 1 and a long axial length. The body-attached portion 6f is provided so as to project. A circumferential groove 6g having a width corresponding to the thickness of the end portion of the upper pipe 1 and a depth of about 3 mm is formed between the outer body-attached portion 6e and the inner body-attached portion 6f. An inner cylindrical portion 6h having the same diameter as the outer diameter of the end portion of the upper pipe 1 is formed. In addition, an outer tapered cylindrical portion 6c is formed on the outer periphery of the inner trunk portion 6f so that the diameter becomes smaller from the base portion toward the end portion.

On the other hand, the diameter of the upper pipe 1 is slightly larger than the inner diameter of the pipe from the end surface, and the diameter becomes smaller toward the center of the pipe, and the inner tapered cylindrical portion 1b having substantially the same slope as the tapered cylindrical portion 6c of the head lug 6 is formed. Has been formed. In this case, the outer surface side seam peripheral line L is formed on the fitting surface between the end surface of the outer trunk portion 6e and the upper pipe 1, while the adhesive layer is formed on the opposing surfaces of both tapered portions.

Third Embodiment Next, a third embodiment of the present invention will be described. FIG. 4 also shows a cross section of the joint portion between the head lug 6 and the upper pipe 1. In this example, the head lug 6 has a cylindrical shape and is provided with a body attachment portion 6 a having a diameter larger than the outer diameter of the upper pipe 1. A cylindrical portion 6i having the same diameter as the outer diameter of the upper pipe 1 and a width of about 3 mm in the axial direction and having a width of about 3 mm is formed on the inner circumference of the body-attached portion 6a. An inner tapered cylindrical portion 6j having a smaller diameter is formed, and a step 6b is formed at the joint between the end of the taper 6c and the base of the body.

On the other hand, the upper pipe 1 has a diameter slightly larger than the outer diameter of the original pipe on the end surface and increases toward the center of the pipe, and the outer taper cylindrical portion 1c of the same inclination as the inner taper cylindrical portion 6j of the head lug 6 is formed. To form.

In this example, the outer surface side seam peripheral line L is formed by the end portion of the body portion 6 a and the outer surface of the upper pipe 1, while the outer peripheral surface joint line L is formed between the cylindrical portion 6 i and the outer surface of the upper pipe 1. Thus, the male / female fitting surface A is formed.

[0025]

[Effect of the invention]

 In the present invention, since the male and female fitting surfaces of the joint and the pipe have the same diameter as described above, the adhesive is sealed at the fitting surface of the pipe end or the fitting end, and heating is performed. It does not stick out from the seam peripheral line on the outer surface side of the pipe due to expansion during curing. Therefore, the work of removing the protruding portion after curing is unnecessary.

Next, at the time of fitting the joint and the pipe, the pipe is guided by the same-diameter cylindrical portion of the joint and is positioned exactly concentrically, so that the tapered cylindrical portion of the joint and the tapered cylindrical portion of the pipe are The gaps in the adhesive layer become uniform, the adhesive strength is improved, and the variation in adhesive strength can be reduced.

Further, since the bicycle is used outdoors, the joint is exposed to water drops, dust, humidity, ultraviolet rays, etc., but in the present invention, the adhesive layer is shielded from the outside world and the adhesive is protected. Therefore, deterioration of the adhesive material can be suppressed.

As described above, according to the present invention, there is a remarkable improvement effect that mass productivity is improved and excellent adhesive strength and durability are obtained while adopting the same bonding method as the conventional one.

[Brief description of drawings]

FIG. 1 is a partially cutaway sectional view of a member showing a first embodiment of the present invention.

FIG. 2 is a partially enlarged sectional view showing a fitted state of the members shown in FIG.

FIG. 3 is a partially cutaway sectional view showing a fitted state of a member according to a second embodiment of the present invention.

FIG. 4 is a partially cutaway sectional view showing a fitting state of members according to a third embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a conventional embodiment.

FIG. 6 is a side view showing a configuration of a bicycle frame body.

[Explanation of symbols]

 1 ... Upper pipe, 1a ... Internal same-diameter cylindrical part, 1b ... Internal tapered cylindrical part, 6 ... Head lug, 6a ..... Body part, 6b .... Step, 6c .... External same-diameter cylindrical part, 6d: External taper cylinder, A: Male / female mating surface, B: Opposed taper surface, L: Outer surface side joint circumference line.

Claims (1)

[Utility model registration claims] 1. In a joint structure of a bicycle frame body in which a pipe is fitted to a cylindrical body-attached portion projecting from a joint and is joined by adhesion, a fitting position of the pipe is determined on the joint side. A step portion is formed to be brought into contact with the end surface of the pipe, and a male and female fitting surface having the same diameter is provided on both members facing the joint circumferential line on the outer surface side of the joint and the pipe. A joint structure for a bicycle frame body, wherein tapered surfaces which can be fitted in series are formed, and the tapered surfaces facing each other at the time of fitting are sealed with an adhesive layer.