JPH0135923Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial field of application) This invention is mainly used in the field of automobiles, etc., and is mainly used in the field of automobiles and the like. The present invention relates to a pipe connection structure that connects a plurality of pipes (also referred to as tubes or stays in this specification) via a joint cylindrical portion.

(Prior art) In recent years, the development of composite materials has been remarkable, and in all fields, including the bicycle industry, CFRP (carbon fiber reinforced plastic) is being used instead of conventional components made of single materials such as iron, aluminum, and duralumin. ) and other non-metallic composite materials have come into use.

For this reason, an adhesive structure has come to be used instead of the conventional welded structure even in the structure of a connecting portion that connects a plurality of members made of these materials.

(Problems to be solved by the invention) However, as mentioned above, when an adhesive structure is adopted for the joining part of pipes of bicycles, etc., compared to conventional welded structures, problems specific to adhesives such as aging In order to obtain sufficient reliability for the bonded part, the bonding area must be reduced to ensure sufficient reliability. They had to be designed larger, and the joints were generally larger than in welded structures.

As described above, when the connecting portion becomes large, the overall design becomes unbalanced, which becomes a big problem in products such as bicycles where the external design greatly influences the value of the product. For this reason,
There is a need for a more compact adhesive structure at the joining part.

The present invention was developed under these current circumstances, and its purpose is to provide a pipe joint structure that can make the joint part more compact without reducing the reliability of the joint part. .

(Means for Solving the Problem) The pipe joining structure according to the present invention is such that one pipe is connected to the other pipe with an adhesive to the joining cylinder formed on the lug that is attached to the other pipe. In the coupling structure in which the inner circumferential surface of the coupling cylinder part is formed into a tapered hole whose diameter expands in one direction, and the outer circumferential surface of the coupling part of the other pipe has a corresponding taper shape that can be inserted into and come into contact with the tapered hole. At the same time, a female thread is formed at the proximal end portion of the inner circumferential surface of the coupling cylinder part, and after inserting the other pipe into the coupling cylinder part from the enlarged diameter side of the coupling cylinder part, A locking body having a male thread portion is provided to be screwed into the threaded portion formed in the coupling cylinder portion from the enlarged diameter side of the coupling cylinder portion, and or, by screwing the locking body into the coupling cylinder part, by forming a step part that the coupling side end surface of the other pipe comes into contact with so as to protrude inward from the inner circumferential surface of the coupling cylinder part, The present invention is characterized in that it also includes a mechanical coupling structure configured to physically prevent the other pipe from being pulled out of the coupling cylinder.

(Function) Therefore, the pipe connection structure constructed in this manner functions as follows. That is, the inner circumferential surface of the coupling tube is formed into a tapered hole whose diameter expands in one direction, and the outer circumferential surface of the coupling portion of the other pipe to be coupled to this coupling tube is formed into a tapered shape that can be inserted into and come into contact with the tapered hole. Therefore, by applying adhesive to one or both of these contacting surfaces and inserting the narrow diameter side of the other pipe into the joint tube part first, rather than the wide diameter side of the joint part, the joint cylinder part and the other pipe come into contact at their tapered portions and can be bonded at these contact surfaces.

Moreover, the other pipe bonded to the coupling tube in this way is further locked by a step formed by the proximal end portion of the inner peripheral surface of the coupling tube or by a locking body, This prevents the pipe from coming off toward the joint part, and also allows the inner circumferential surface of the joint cylinder part and the outer circumferential surface of the other pipe to come into contact with each other in a physically matched state at each part at the tapered surface part, thereby preventing the pipe from coming off the other pipe. The pipe is mechanically (physically) connected to prevent the pipe from being pulled out to the opposite side of the joint. Therefore, even if the adhesive and the adhesive effect on the tapered surface deteriorate, the connection between the other pipe and the connecting tube will not be released.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a side sectional view of a connecting portion between a down tube and a seat tube of a bicycle. In the figure, 1 is a down tube, 2 is a seat tube,
3 and 4 are joint cylinder portions formed in the pipe 5, and 6
is a locking body.

The inner and outer peripheral surfaces of the connecting portions 1a and 2a at the tips of the down tube 1 and the seat tube 2 are formed into a tapered shape that gradually becomes smaller in diameter on the tips of the tubes.

In addition, the inner peripheral surfaces 3a, 4a of the coupling cylinder parts 3, 4
is formed into a tapered hole that gradually becomes smaller in diameter on the proximal end side of the joint tube so as to be in substantially intimate contact with the outer peripheral surface of the joint portions 1a, 2a of the down tube 1 or seat tube 2. . In this embodiment, step portions 3b and 4b protrude inwardly by a dimension equal to the thickness of the down tube 1 and the seat tube 2, further toward the proximal end of the narrowest taper hole of the inner circumferential surfaces 3a and 4a. are provided, and a female thread 7 is formed on the inner circumferential surface of the stepped portions 3b, 4b.

The distal end portion 6a of the locking body 6 is formed with a male thread 8 which is screwed into the female thread 7 formed on the step portions 3b and 4b, and the outer circumferential surface 6b on the proximal end thereof is formed on the down tube 1. Alternatively, it is formed into a corresponding tapered shape that can be inserted into and brought into contact with the tapered shape (tapered hole) formed on the inner circumferential surface of the connecting portions 1a, 2a at the tip of the seat tube 2. Further, in this embodiment, the outer circumferential surface 6c on the proximal end side is formed into a straight body shape with an equal cross section, and this portion has a gap between it and the inner circumferential surface of the down tube 1 or the seat tube 2. The outer diameter is such that this occurs. In the case of this embodiment, this locking body 6 is formed with a hexagonal hole 6d.

The pipe coupling structure having such a configuration is assembled in the following order. Hereinafter, since the configuration is the same, the coupling cylinder part 3 and the down tube 1
To explain the connection using an example, adhesive is attached to the tapered hole part of the inner circumferential surface 3a of the coupling cylinder part 3, or to the tapered part of the outer circumferential surface of the coupling part 1a of the corresponding down tube 1, or to both surfaces. Apply the agent,
The down tube 1 is inserted into the joint tube portion 3 so that both tapered surfaces are generally in contact with each other.

Next, insert the locking body 6 into the tube from the proximal end of the down tube 1, insert a hexagonal wrench into the hexagonal hole 6d of the locking body 6, and insert the hexagonal wrench into the hexagonal hole 6d formed at the tip of the locking body 6. The male thread 8 and the female thread 7 formed in the stepped portion of the coupling cylinder portion 3 are screwed together. When this screwing is completed, the end face of the tip of the down tube 1 comes into contact with the end face of the stepped part 3b of the coupling cylinder part 3, and both tapered surfaces come into complete contact to perform adhesion.

In this way, when the down tube 1 is connected to the joint tube 3, when an axial force (tensile force) is applied to the down tube 1 to separate it from the joint tube 3, the connection tube 1 is moved on both tapered surfaces. Since the part 3 and the down tube 1 are bonded with adhesive, the locking body 6 screwed into the joint cylinder part 3 is combined with the joint cylinder part, and the outer peripheral surface of the locking body 6 and the joint cylinder part are connected. Since the down tube 1 is held between the inner circumferential surfaces, the force in the axial direction acts as a force in a direction that expands the diameter of the joint portion of the down tube 1 and the joint cylinder portion 3 or contracts the diameter of the locking body 6. Moreover, it also acts as a force that peels off the adhesive portions on the inner and outer circumferential surfaces of the down tube 1. Also, down tube 1
Force in the axial direction (compressive force) to bring the coupling cylinder portion 3 closer to the
When this occurs, a force is applied in such a direction that the end face of the down tube 1 presses against the stepped portion of the joint cylinder portion 3, and a force is applied in a direction that causes the adhesive portions of the inner and outer peripheral surfaces of the down tube 1 to peel off. Acts as.

Therefore, even if the connecting part is made sufficiently compact in terms of structure, the force that resists the above-mentioned axial force (tensile force or compressive force), that is, the connecting part of the down tube 1 and the connecting cylinder part is enlarged in diameter or the locking body The force that resists the force that reduces the diameter of the down tube 1 and the force that peels off the adhesive parts on the inner and outer circumferential surfaces of the down tube 1 is usually
Even when the safety factor is taken into account, the structure can be made to be more than enough larger than the external force acting on the joint portion.

Similarly, even when a force (bending stress) perpendicular to the axial direction of the down tube 1 is applied, it changes (decomposes) into a force (component force) in roughly the same direction.
It can be configured to be more than adequate.

In addition, a different part from the above embodiment, namely the chain stay (pipe) at the rear of the bicycle as shown in FIG.
5' and the seatstay (pipe) 1', the dimensions (external shape) will be slightly different due to the difference in the thickness of the pipes, but the same as in the above embodiment. It can be implemented in the same way.

Next, another embodiment of the present invention will be described by taking as an example the connecting portion between the down tube 1'' and the connecting tube portion 3'' of the lug 9 inserted into the head tube 10.

As shown in FIG. 3, this embodiment differs from the above embodiment in that the direction of the taper is reversed. That is, the inner and outer circumferential surfaces of the connecting portion 1a'' at the tip of the down tube 1'' are formed in a tapered shape that gradually increases in diameter on the tip side, and the inner circumferential surface 3a'' of the connecting tube 3'' is Connection part 1 of the above down tube 1″
The difference is that the hole is formed into a tapered hole whose diameter gradually increases on the proximal end side so as to be in almost intimate contact with the outer circumferential surface of the inner circumferential surface 3a''. A straight hole is formed from the thickest tapered hole part to the proximal end, and a female thread 7'' is formed in this part.On the other hand, on the outer periphery of the locking body 6'', the connecting cylinder part 3'' is formed. A male screw 8'' is formed on the end surface of the locking body 6'' to be screwed into the female screw 7''.
A tool engages when rotating this locking body 6″.
An engagement hole 6a'' (see broken line) is formed.

The pipe coupling structure having such a configuration is assembled in the following order. That is, the adhesive is applied to the tapered hole portion of the inner circumferential surface 3a'' of the coupling tube 3'', or to the tapered portion of the outer circumference of the coupling portion 1a'' of the corresponding down tube 1'', or to both surfaces, The down tube 1'' is inserted into the connecting cylinder part 3'' of the lug 9 from the enlarged diameter side of the connecting cylinder part 3'' so that both tapered surfaces are generally in contact with each other.

Next, the locking body 6'' is inserted from the proximal end side of the coupling cylinder 3'', and the male thread 8'' of the locking body 6'' is at the end of the female thread 7'' formed in the coupling cylinder 3. Insert the tool into the engagement hole 6a'' of the locking body 6'' while making contact with the
The male thread 8'' of the locking body 6'' and the female thread 7'' are screwed together until the tapered surfaces of both the outer circumferential surface of the down tube 1'' and the inner circumferential surface of the coupling cylinder portion 3'' completely come into contact.
The connection is now complete.

In this way, in the state in which the down tube 1'' is connected to the connecting cylinder portion 3'' of the lug 9, the forces (tensile force, compressive force, bending stress) acting on the down tube act in the same manner as in the above embodiment. However, since the direction of the taper is opposite, and because the locking body 6'' is screwed from the coupling cylinder part 3'' from the opposite direction, the end face of the down tube 1'' , the axial compressive force acting on the down tube 1'' presses the locking body 6'', and the tensile force causes the down tube 1'' to contract. It acts as a force in the direction of expanding the diameter or the diameter of the coupling cylinder portion 3''.

(Effects of the Invention) As described above, the present invention has both an adhesive-based bonding structure and a mechanical bonding structure, so that higher reliability can be obtained compared to a bonding structure using only an adhesive. Therefore, there is no need to increase the size of the bonded portion to ensure reliability, unlike in conventional bonded structures. In other words, it can be made much more compact while maintaining the same reliability.

Therefore, if this coupling structure is adopted for bicycles, etc.,
It is possible to provide a bicycle or the like with an attractive design without large joints, as is the case with conventional welded constructions.

[Brief explanation of the drawing]

Fig. 1 is a side cross-sectional view of a joint between a down tube and a seat tube of a bicycle according to an embodiment of the present invention; FIG. 3 is a side sectional view showing a joint portion between a head tube and a down tube of a bicycle showing another embodiment of the present invention. 1... Down tube (other pipe), 1'...
...Seat stay (other pipe), 1a...Connecting tube part, 2...Seat tube (other pipe),
2a...Joining cylinder part, 3, 4...Joining cylinder part, 3a,
4a...Inner circumferential surface of coupling cylinder part, 5...Pipe (one pipe), 5'...Chain stay (one pipe), 6...Locking body, 7...Female thread, 8...O Screw, 9... Lug, 10... Head tube (one pipe).

Claims (1)

[Claims for Utility Model Registration] In a coupling structure in which a coupling tube formed on one pipe or formed on a lug attached to this pipe is coupled to the other pipe using an adhesive, said coupling tube The inner circumferential surface of the connecting tube is formed into a tapered hole whose diameter expands in one direction, and the outer circumferential surface of the connecting portion of the other pipe is formed into a corresponding tapered shape that can be inserted into and in contact with the tapered hole, and the inner peripheral surface of the connecting tube portion A female thread is formed at the base end portion of the pipe, and after the other pipe is inserted into the joint cylinder from the enlarged diameter side of the joint cylinder, a female thread is formed at the base end of the pipe. A locking body having a male thread portion to be screwed into the threaded portion is provided, and the locking body is provided at the threaded proximal end portion of the inner circumferential surface of the coupling cylinder part itself or on the coupling cylinder part. By screwing the two pipes together, the step portion that the joining side end surface of the other pipe abuts is formed to protrude inward from the inner peripheral surface of the joining cylinder, so that the other pipe can be pulled out from the joining cylinder. A pipe joint structure characterized by having a mechanical joint structure configured to physically prevent pipes from coming off.