JPH03231087A - Joint structure of bicycle frame body - Google Patents

Abstract

PURPOSE:To eliminate the bulging-out an adhesive from a relaying peripheral line on the outside surface sides of a coupling and a pipe and improve the outside appearance and workability by forming the male and female fitted surfaces having an equal diameter on the coupling and the pipe. CONSTITUTION:A trunk attached part 6a is formed on a head lug 6, and a stage part 6b is formed on the trunk attached part 6a. Further, an outside equal diameter cylinder part 6c is formed on the stage part 6b, and an outside tapered cylinder part 6d whose outside diameter reduces towards the edge part is formed continuously to the outside equal diameter cylinder part 6c. While, an upper pipe 1 has an inside equal diameter cylinder part 1a formed on the edge part inner surface, and an inside tapered cylinder part 1b whose inside diameter reduces towards the inside of the upper pipe 1 is formed. The outside and inside equal diameter cylinder parts 6c and 1a are fitted each other, and a male and female fitted surface A is formed. Further, the outside and inside tapered cylinder parts 6d and 1b are fitted each other, and an opposed tapered surface B is formed continuously to the male and female fitted surface A.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in adhesive bonding between a joint and a pipe in a bicycle frame.

In recent years, light metals (
Pipes made of materials such as aluminum, titanium, etc.), FRP (fiber-reinforced plastic), and FRM (fiber-reinforced metal) are attracting attention. However, these new material pipes cannot be joined by welding or brazing like conventional steel pipes. Therefore, in order to use these pipes in bicycle frames, there is a strong demand for improvements in bonding technology using adhesives.

As shown in Fig. 5, the frame body of the bicycle includes an upper vibe 1, a lower vibe 2, a standing vibe 3, a back hawk 4,
It is constructed by joining various thin-walled pipes of the chainstay 5 and various joints of the spatula drag 6, hanger lug 7, seat lug 8, and rear claw 9.

Although not shown, an example of conventional joining is disclosed in Japanese Utility Model Application No. 57-81.
As described in Publication No. 91, a step part and a tapered cylindrical part are simply formed on the outer periphery of the barrel part of the head lug, and this is further improved as shown in FIG. As shown in FIG. 2, a stepped portion 6b and an outer tapered cylindrical portion 6c are formed on the outer periphery of the trunked portion 6a of the head lug 6, and an inner tapered cylindrical portion 1a is formed at the tip of the upper vibrator l, and an adhesive is applied to a portion of both tapers. After coating, the upper vibrator 1 was fitted into the body attachment portion 6a, and the end surface of the upper vibrator 1 was brought into contact with the five-step portion 6b for positioning. that time,
A predetermined gap was secured by the difference in diameter between the opposing tapers, and this gap was used as an adhesive layer.6 When curing the adhesive, each pipe and joint shown in Figure 5 are fitted together at the same time. It was assembled as a frame body, and the whole was heated while maintaining its shape.

(Problem to be Solved) However, in the above-mentioned adhesive bonding method, the end surface of the upper vibrator 1 is brought into contact with the stepped portion 6b of the head lug 6 for positioning, so the pipe end surface, that is, the line between the joints on the outer surface side L Originally, there should be no gap, but it is inevitable that some gap will be formed due to dimensional errors in the pipe length or assembly errors.

Since the adhesive lO filled in the gap between the five tapered ends expands when heated, a portion of the adhesive protrudes outward from this gap, that is, the line between the seams L4 on the outer surface side, and hardens as it is. was often the case.

Therefore, it is necessary to remove the adhesive 11 that protrudes from the line L between the joints, but it is extremely troublesome to cleanly remove only the protruding part so as not to damage the surface of the pipe or joint. It was a lot of work.

Moreover, as shown in FIG. 5, one frame body has a large number of joints, which requires a large number of man-hours and is not suitable for mass production.

(Means for Solving) In order to solve the above-mentioned problems, the present invention employs the following solving means.

That is, in a joint structure of a bicycle frame body in which a pipe is fitted into a cylindrical body part protruding from a joint and bonded by adhesive, the vibrator is used to determine the fitting position of the pipe on the joint side. forming a stepped portion that abuts the end surface of the
Facing the line between the seams on the outer surface side of the joint and the pipe, both members are provided with male and female mating surfaces of the same diameter, and furthermore, a tapered surface that can be mated is formed in series with this mating surface, and when mated, It is characterized in that the opposing tapered surfaces are sealed with an adhesive layer.

Since the present invention is constructed as described above, there is no possibility of any adhesive material protruding from the line between the joints on the outer surface side of the joint and the pipe.

That is, since the fitting surfaces of both members facing the line between the seams on the outer surface side are male and female fitting surfaces of the same diameter, it is possible to prevent the adhesive 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 negative gap means that the diameter is larger on the male side when mating, which reduces the manual mating effect. More preferably, the gap is 0 to 0.1 mm.

By setting the width of the fitting surface to be larger than the expected dimensional error and assembly error of the pipe length, it is possible to prevent gaps from being formed due to these axial errors.

The width of the fitting surface is arbitrary, but about 3 mm is sufficient.

Furthermore, the tapered surfaces formed on both members that are connected to the mating surfaces act to pressurize and uniformly stretch the adhesive applied there during mating, and the gap between both tapered surfaces is formed by the adhesive layer. It will be buried.

In general, there are many types of adhesives, but liquid thermosetting adhesives are the most suitable for bonding bicycle frames because of their excellent adhesive strength, adhesive durability, and workability. Here-
The liquid thermosetting type refers to one that is heated to about 120°C and hardens in about 1 hour.

With the above configuration, the adhesive material does not protrude from the seam circumferential line during bonding.

(Example) Examples of the present invention will be described below with reference to the drawings, focusing on the connection between the head lug and the upper vibe.

Embodiment 1 FIG. 1 is a partial sectional view of the head lug 6 and the upper vibrator 1, and FIG. 2 is a partial sectional view showing the bottom of both members.

The head lug 6 is provided with a protruding cylindrical body part 6a having the same diameter as the outer diameter of the upper vibrator l, which will be described later. A stepped portion 6b is formed on this trunked portion 6a, and this has a step corresponding to the thickness of the end surface of the upper vibrator l.

Now, this stepped portion 6b forms a seam line L on the outer surface side with the upper vibrator l, and an outer same-diameter cylindrical portion 6c is formed from this stepped portion 6b, which is connected to the upper vibrator l.
This is the separation fitting surface A. It is sufficient that the width of this outer cylindrical portion 6C having the same diameter is about 3 mm.

Further, an external tapered cylindrical portion 6d is formed continuously from the same-diameter external cylindrical portion 6c, the outer diameter of which decreases toward the end.

On the other hand, the upper vibrator l has an internal same-diameter cylindrical part 1a with a width of about 3 mm formed on the inner surface of the end that forms the outer surface side seam circumferential line L together with the step part 6b, and from this, the inside of the upper vibrator l An internal tapered cylindrical portion 1b is formed, the inner diameter of which decreases toward the inner diameter. Note that the terminal end of the tapered part is the inner diameter of the original pipe.

Here, the outer same-diameter cylindrical portion 6c of the trunk attachment portion 6a and the upper vibe l
It has the same diameter as the inner cylindrical portion 1a of the same diameter, and these fit into each other to form a separation fitting surface A.

Further, an external tapered cylindrical portion 6d and an internal tapered cylindrical portion 1t.
') are those which can be fitted with approximately the same slope, and these form a tapered surface B that is continuous with and faces the ts female fitting surface A.

In order to bond the head lug 6 and the upper vibrator l, an adhesive is applied to the surfaces of the tapered cylindrical portions 6d and lb of the head lug 6 and the upper vibrator 1, and these two members are fitted together. At this time, first, the adhesive material sandwiched between both tapered cylindrical portions is pressurized as the gap between the tapers becomes narrower, and is uniformly and thinly stretched.

In this way, the end of the outer same-diameter cylindrical part 6c of the head lug 6 and the end of the inner same-diameter cylindrical part 1a of the upper vibrator l come close to contacting each other. Positioning is performed by abutting the end surface against the stepped portion 6a of the head lug 6. Here, an outer surface side seam circumferential line L is formed between the upper vibe 1 and the stepped portion 6a of the trunked portion 6.

At this time, a predetermined gap is created due to the difference in diameter between the opposing taper portions of both members, and this becomes the thickness of the adhesive layer. At this time, excess adhesive material protrudes to the outside of the upper vibrator 1, that is, to the seam circumferential line L and to the inside of the upper vibrator 1.

A similar operation is performed on the hanger lugs 7, seat lugs 8, and rear claws 9, and after wiping off the adhesive for assembly as a frame body, they are heated and cured.

Even if the adhesive expands or increases its fluidity during this heating and curing process, since the mating surface A of the same diameter is formed by both members, even if there is a dimensional error or assembly error, both members No radial gap is created between them, and therefore, the adhesive material will not protrude from the inside along the outer surface side seam circumferential line L.

Embodiment 2 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 vibrator l.

The head lug 6 has an outer barrel part 6e which is cylindrical and has a larger diameter than the upper vibe 1 and is shorter in the axial direction, and an inner barrel part 6e which is concentric with this and has a smaller diameter than the upper vibe l and is longer in the axial direction. A protruding portion 6f is provided.

A circumferential groove 6g with a width equivalent to the wall thickness of the end of the upper vibrator l and a depth of about 3 mm is formed between the outer body attachment part 6e and the inner body attachment part 6f, and the inner circumference of the outer body attachment part 6e is form the top. Further, an external tapered cylindrical portion 6C is formed on the outer periphery of the inner barrel pair portion 6[, the diameter of which decreases from the base toward the end.

On the other hand, the upper vibrator 1 has an internal tapered cylindrical portion 1b having a diameter that is slightly larger than the inner diameter of the pipe from the end surface and becomes smaller toward the center of the pipe, and has an almost same slope as the tapered cylindrical portion 6C of the spatula drag 6. There is.

In this case, the outer surface side joining diurnal line L is the outer body pairing portion 6e.
The contact layer is formed on the fitting surface between the end surface of the upper vibrator L and the upper vibrator l, while the front layer is formed on the opposing surface of a portion of both tapers.

Example 3 Next, a third embodiment of the present invention will be described.

] -1 Figure 4 shows the connection between the head lug 6 and the upper vibe 1.
, shows a cross section of the cram school. In this example, the head lug 6 has a cylindrical body part 6a projecting therefrom and having a diameter larger than the outer diameter of the upper vibe I.

A cylindrical part 61 having the same diameter as the outer diameter of the upper vibrator 1 and the male diameter and having a width of about 3 mm in the axial direction is formed on the inner periphery of the end of the 3-barrel pair part 6a, An internal tapered cylindrical portion 6J is formed such that the diameter becomes smaller toward the taper 6.
The connecting part between the end of 0 and the base of the body attachment part is defined as a step 6b.

On the other hand, the -do pipe l has a diameter that is slightly smaller than the outer diameter of the original pipe at the end face, and increases in diameter toward the center of the pipe, forming an external tapered cylindrical portion 1c having approximately the same slope as the internal tapered cylindrical portion 6J of the head lug 6. .

In this example, an outer surface side joining diurnal line L is formed by the end of the body pair part 6a and the outer surface of the upper vibrator 1, while a male and female fitting is formed between the cylindrical part 61 and the outer surface of the upper vibrator 1. A face A
will be formed.

(Effects) In the present invention, as described above, both the joint and the pipe have male and female fitting surfaces of the same diameter, so the adhesive seals the fitting surfaces of the pipe end or joint flat end. Therefore, it will not protrude from the joint diurnal line on the outside surface of the pipe due to expansion during heat curing. Therefore, there is no need to remove the protruding portion after curing.

Next, when the joint and the pipe fit together, the pipe is guided by the same-diameter cylindrical part of the joint and is positioned accurately concentrically, so that the adhesive layer gap between the tapered cylindrical part of the joint and the tapered cylindrical part of the pipe is It becomes uniform, the adhesive strength is improved, and variations in the adhesive strength can be reduced.

Furthermore, since bicycles are used outdoors, the joints are exposed to water droplets, flakes, moisture, ultraviolet rays, etc. However, in the present invention, the adhesive layer is shielded from the outside world and the adhesive material is protected. Deterioration of the adhesive can be suppressed.

As described above, according to the present invention, while employing the same bonding method as in the past, there is a remarkable improvement in that mass productivity is improved and excellent adhesive strength and durability can be obtained.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway sectional view of a member showing a first embodiment of the present invention, and FIG. 2 is a partially cutaway sectional view of a member showing a second embodiment of the member shown in FIG. 4 is a partially cutaway sectional view showing a fitted state of members showing a third embodiment of the present invention; FIG. 5 is a sectional view showing a conventional embodiment;
FIG. 6 is a side view showing the structure of the bicycle frame body.
(Explanation of symbols) 1...Upper vise la...Internal same-diameter cylindrical part, lb...Internal tapered cylindrical part, 6...
Head lug, 6a...Body pair part, 6b...Step part, 6c...External same diameter cylindrical part, 6d...External tapered cylindrical part. lλ...Male A fitting surface, B...Opposing tapered surface, L...Outer surface side joint line.

Claims (1)

[Claims] (1) In a bicycle frame joint structure in which a pipe is fitted into a cylindrical body part protruding from a joint and bonded by adhesive, the pipe is used to determine the fitting position of the pipe on the joint side. forming a stepped portion that abuts the end surface of the
A male and female mating surface of the same diameter is provided on both members facing the joint circumference line on the outer surface side of the joint and the pipe, and a tapered surface that can be mated is formed in succession to this mating surface. A joint structure for a bicycle frame body, characterized in that the opposing tapered surfaces are sealed with an adhesive layer.