JPH0587681B2 - - Google Patents

Description

Detailed Description of the Invention [Industrial Application Field] This invention connects pipes by using an adhesive interposed between the pipe and an insertion part that protrudes from a joint body and is inserted into the end of the pipe. related to pipe fittings.

[Prior art] This type of pipe joint has conventionally been manufactured by Japanese Patent Application Laid-Open No.
There are those disclosed in No. 181785. This includes a joint body and an insertion part that projects from the joint body and is inserted into the end of the pipe, and the insertion part includes:
By forming a loose insertion part at the tip and a pressure insertion part on the joint body side, an adhesive is interposed between the outer periphery of the loose insertion part and the inner periphery of the tube, and the pressure insertion part and the inner periphery of the tube are crimped. Then, the joint body and the pipe are connected by this crimping and bonding with the adhesive.

[Problem that the invention seeks to solve]

However, for such pipe joints,
The pipe and the pressure insertion part are crimped at the end of the pipe, and a loose insertion part is formed inside the crimp part in the longitudinal direction of the tube, so there is no adhesive in the loose insertion part. However, if a bending moment acts on the tube relative to the insertion part before the adhesive hardens, causing a misalignment between the axis of the tube and the axis of the insertion part, the gap in the loose insertion part will be deformed. Then, there is a risk that the adhesive interposed therein will be uneven and leakage may occur in some parts, and if the adhesive hardens as it is, the tube and insertion part will be glued together with the misalignment. There is.

The present invention has been made by focusing on the problems of the prior art, and is designed to prevent the tube from bending even if a relative bending moment is applied between the insertion portion and the tube before the adhesive hardens. The purpose is to provide a pipe joint that does not cause misalignment between the shaft and the shaft of the insertion part.

[Means for solving problems]

The pipe joint of the present invention includes a joint body, an insertion part that protrudes from the joint body and is inserted into the end of the pipe, and the insertion part has a pressure insertion part that presses against the inner circumference of the pipe, and a pressure insertion part that presses against the inner circumference of the pipe. a loosely inserted part in which a gap for adhesive is formed between the pipe and the inner periphery of the joint body, and the pipe is joined to the joint body by pressure contact at the pressure-inserted part and adhesion at the loosely inserted part. The premise is that the pressure insertion part is formed by a continuous protrusion in the insertion direction of the insertion part, and a plurality of pressure insertion parts are formed in the circumferential direction of the insertion part, and the pressure insertion part and the loose insertion part are formed. and are arranged alternately in the circumferential direction, and the protrusions forming the pressure insertion part have a trapezoidal cross section, the width of the upper surface is significantly narrower than the width of the loose insertion part, and an outwardly chamfered part at the tip of the insertion part. A circumferential leakage prevention part that fits into the inner periphery of the open end of the tube to prevent leakage of the adhesive is connected to the press insertion part at the end of the insertion part near the joint body. The tube into which the insertion portion is inserted has an inwardly chamfered portion at its distal end.

[Effect]

Fill the loose insertion section of the insertion section with adhesive, and insert the insertion section into the tube from the tip. At this time, the insertion section is press-fitted into the tube with the upper end surface of the protrusion forming the press-insertion section pressed against the inner surface of the tube. Since a plurality of press insertion portions are formed in the circumferential direction of the tube, during the press fitting, the axis of the insertion portion and the axis of the tube are kept aligned throughout, and the press fitting progresses. Therefore, no large force is applied to the adhesive in the loosely inserted portion during press-fitting, and no change in volume occurs.

The protrusion forming the pressure insertion part has a trapezoidal cross section and the width of the upper surface is much narrower than the width of the loose insertion part, so the area of pressure contact with the inner surface of the tube is small, so the frictional resistance is relatively small. Therefore, the press-fitting is easy. Further, since the width of the upper surface of the protrusion is small, the width of the loosely inserted portion becomes large, and the bonding area of the adhesive interposed therein becomes large, so that the adhesive force with the inner surface of the tube can be strengthened. Furthermore, if the width of the upper surface of the protrusion is small and the diameter of the circumscribed circle of the protrusion is larger than the inner diameter of the tube, at least one of the two in pressure contact with each other may be deformed, or one may bite into the other, causing both to be damaged. are firmly pressed together.

In addition, due to the inward chamfer at the tip of the tube,
The adhesive is leveled during the press-fitting. That is, the surface of the adhesive filled in the loose insertion portion rarely matches the inner surface of the tube, and in most cases, some unevenness is formed. Therefore, by the relative movement of the tip of the tube during press-fitting, the chamfer scrapes off the convex part of the adhesive, moves the remaining part of the adhesive, and supplies it to the concave part of the adhesive to even out the entire surface. . Since the chamfer faces inward, its movement forces the remaining adhesive into the recess and fills it, thereby preventing the formation of air pockets in the loosely inserted part.

In the final step of press-fitting, since the leak prevention part is formed continuously to the press insertion part, the pipe is continuously guided from the press insertion part to the leak prevention part. For this reason, the press-fitting is performed smoothly by a series of flows from the beginning to the end of the process without any changes such as an increase in frictional force during the process. The inner periphery of the open end of the tube comes into pressure contact with the circumferential leakage prevention part, and this contact is made in the entire circumferential direction of the tube, so the adhesive will not leak into the opening of the tube after press-fitting is completed. .

In addition, even if the insertion of the insertion part into the tube is completed and the adhesive is still in an uncured state, a plurality of continuous pressure insertion parts are formed in the circumferential direction of the tube along the axial direction of the insertion part, and these press insertion parts are formed on the inner surface of the tube. Since the tube is in pressure contact with the tube, even if a bending moment is applied to the tube, the axis of the insertion portion and the axis of the tube are maintained in alignment. Therefore, even at this point, no excessive force is applied to the adhesive, and the insertion portion and the tube are connected firmly and without bending as the adhesive hardens.

Even if bending force is applied between the pipe and the fitting body after connection, stress will be concentrated on the pipe outside this part because the tip of the insertion part has an outward chamfer at the pressure insertion part. Since there are no cracks in the pipe, it is possible to prevent cracks from occurring in the pipe.

〔Example〕

Hereinafter, an embodiment in which the pipe joint of the present invention is applied to a pipe joint constituting a bicycle frame will be described.

This pipe joint includes a joint body 1 and a joint body 1.
an insertion part 3 that is protruded from and inserted into the end of the tube 2;
The insertion portion 3 is provided with an adhesive 4 between the pressure insertion portion 31 that presses against the inner periphery of the tube 2 and the inner periphery of the tube 2.
A loose insertion portion 32 is formed in which an intervening gap 5 is formed.

The pressure insertion part 31 is formed of a continuous protrusion in the insertion direction of the insertion part 3, and its height is the same throughout the entire body except for the outward chamfered part 3a formed at the tip of the insertion part 3. The dimensions are as follows. By forming a plurality of pressure insertion portions 31 in the circumferential direction of the insertion portion 3, the pressure insertion portions 31 and the loose insertion portions 32 are arranged alternately in the circumferential direction. In this embodiment, eight press insertion portions 31 are formed at equal intervals in the circumferential direction, but the number can be arbitrarily selected as long as it is three or more.

Further, at the end of the insertion portion 3 near the joint body 1, the adhesive material 4 is fitted to the inner periphery of the open end of the tube 2.
A circumferential leak prevention part 6 is formed to prevent leakage of the liquid.

The diameter of the circumscribed circle of the pressure insertion part 31 is the same as the inner diameter of the tube 2, or the former is slightly larger, so that the pressure insertion part 31 is the same as the inner diameter of the tube 2.
The outer diameter of the leak prevention part 6 and the inner diameter of the pipe 2 are approximately the same. Leakage prevention part 6
The outer diameter of the leak prevention part 6 is set to prevent leakage of the adhesive 4 between the pipe 2 and the pipe 2.
It is sufficient that the outer periphery of the tube 2 and the inner periphery of the end opening of the tube 2 are in contact with each other. Therefore, the width 6a (length in the axial direction of the insertion portion 3) of the leakage prevention portion 6 may be small, and the width 6a of the leakage prevention portion 6 may be small.
It is sufficient if the width 6a of the leakage prevention part 6 is slightly larger than the chamfered part 2a of the opening end.

The press-insertion part 31 has a trapezoidal cross section and a narrow upper surface to reduce frictional resistance with the tube 2 during insertion, thereby ensuring smooth insertion work. . Furthermore, due to the shape of the press-inserted portion 31, the diameter of the circumscribed circle of the press-inserted portion 31 is
If the inner diameter is slightly larger than the inner diameter of the tube 2, at least one of the upper surface of the pressure insertion section 31 and the inner surface of the tube 2 will be slightly shaved or deformed, so that the insertion of the insertion section 3 into the tube 2 will not be smooth as described above. In contrast, the fixing force between both 2 and 31 after insertion is large. At this time, if the upper surface of the pressure insertion part 31 digs into the inner surface of the tube 2 due to the difference in material and strength between the insertion part 3 and the tube 2,
The bonding force between the insertion portion 3 and the tube 2 increases not only in the direction of relative rotation but also in the insertion direction.

To join the tube 2 to this tube joint, first, the loose insertion section 32 of the insertion section 3 is filled with adhesive 4, and then the insertion section 3 is inserted into the end of the tube 2 from the tip. At this time, the press-insertion part 31 is sequentially inserted into the tube 2 starting from the chamfered part 3a, and the insertion part 3 is press-fitted into the tube 2 with friction between the outer surface of the press-insertion part 31 and the inner surface of the tube 2.

Since the press-insertion part 31 is formed of a protrusion continuous in the longitudinal direction of the insertion part 3 and has the same height in the longitudinal direction, it is not connected to the axis of the insertion part 3 when the insertion part 3 is press-fitted. It is forced to remain aligned with the axis of the tube 2. Therefore, even if a bending moment acts on the joint body 1 or the pipe 2, both 2 and 3
There is no difference in position or posture between the two. Therefore, since no volume change occurs in the adhesive 4 in each gap 5, the required amount of the adhesive 4 in each gap 5 is ensured, and hence a sufficient adhesive force is ensured later.

In addition, when the insertion part 3 is press-fitted into the tube 2, the adhesive 4 of the loose insertion part 32 is leveled by the inwardly chamfered part 2a at the tip of the tube 2. That is, the surface of the adhesive 4 rarely matches the inner surface of the tube 2 before being press-fitted, and in most cases, some unevenness is formed. Therefore, by the relative movement of the tip of the tube 2 during press-fitting, the chamfered part 2a scrapes off the convex part of the adhesive 4, moves the remaining part of the adhesive, and supplies it to the concave part of the adhesive 4. Level the whole thing. At this time, since the chamfered part 2a faces inward, the excess adhesive is pushed into the recessed part by its movement and is filled, thus preventing the formation of air pockets in the loosely inserted part 32 after press-fitting. be done.

In this final step of press-fitting, the inner surface of the open end of the tube 2 comes into contact with a part of the leakage prevention section 6 in the width 6a direction. Since this contact is made around the entire circumference of the leakage prevention part 6, the adhesive 4 will not leak from between the joint body 1 and the end of the pipe 2 after the press-fitting is completed.

In this way, when the insertion part 3 has been press-fitted into the tube 2, the adhesive 4 is in a state where the insertion part 3 is press-fitted into the tube 2 at the press-insertion part 31 that spans almost the entire length of the insertion part 3. Even if uncured, the axis of the tube 2 and the axis of the insertion part 3 are temporarily fixed in the same state, and even if a moment is applied to the joint body 1 or the tube 2, the position and position between the two and 3 will not change. There will be no misalignment of posture. Therefore, even after press-fitting is completed, no volume change occurs in the adhesive 4 in each gap 5, and the required amount of adhesive 4 in each gap 5 is secured as before, so that after curing Sufficient adhesive force is ensured. When the insertion section 3 and tube 2 are temporarily fixed, the adhesive 4
harden. When the adhesive 4 is thermosetting,
The parts assembled using this joint are introduced into an oven and heated to harden. At this time, the temporary fixation of the insertion part 3 and the tube 2 has sufficient fixing force as described above, so there is no need for a jig to fix each part, and no jig is required. However, a small scale jig is sufficient. For this reason,
The oven has high volumetric efficiency and saves thermal energy for heating the jig. Even if a bending force is applied between the pipe 2 and the joint body 1 after the joint body 1 is connected to the pipe 2, the tip of the insertion part 3 will not press into the insertion part 3.
Since there is an outwardly facing chamfered portion 3a in 1,
Since stress is not concentrated on the tube 2 outside this portion, it is possible to prevent cracks from occurring in the tube 2.

FIG. 4 shows an example of a bicycle frame constructed using the pipe joint of this embodiment. That is,
Using head lug A, seat lug B, and hanger lug C as pipe joints, upper pipe 21 and lower pipe 2
2. The vertical pipe 23 is continuous as shown.

In the above embodiments, the present invention was applied to a pipe joint constituting a bicycle frame, but it is of course applicable to other pipe joints.

〔Effect of the invention〕

As explained above, according to the present invention, the protrusion forming the pressure insertion part is continuous in the axial direction (insertion direction) of the insertion part, and the upper end surface of each pressure insertion part is pressed against the inner surface of the tube. Since the insertion part is press-fitted into the pipe in this state, even if a relative bending moment is applied between the insertion part and the pipe, there will be no misalignment between the axis of the pipe and the axis of the insertion part, and the press-fit will not occur. The axis of the insertion portion and the axis of the tube are maintained in alignment throughout the entire time and after the end of the period. Therefore, no large force is applied to the adhesive in the loosely inserted portion during press-fitting and after press-fitting, and no volume change occurs. Therefore, there is an effect that the pressure insertion part and the pipe are connected firmly and without bending by the hardening of the adhesive.

Further, according to this invention, since the width of the upper surface of the protrusion forming the press-insertion part is made much narrower than the width of the loose-insertion part, the frictional resistance with the inner surface of the tube is relatively small, making press-fitting easy. It is. Further, since the width of the upper surface of the protrusion is small, the width of the loosely inserted portion becomes large, and the bonding area of the adhesive interposed therein becomes large, so that the adhesive force with the inner surface of the tube can be strengthened.

In addition, due to the inward chamfer at the tip of the tube,
During the press-fitting process, the adhesive on the loosely inserted part is evened out. In other words, the surface of the adhesive on the loosely inserted part is rarely in line with the inner surface of the tube, and in many cases there are some irregularities, so the relative movement of the tip of the tube during press-fitting will cause the chamfered part to scrapes off the convex portion of the adhesive, moves the remaining adhesive, and supplies it to the concave portion of the adhesive to level the entire surface. Since the chamfer faces inward, its movement forces the remaining adhesive into the recess and fills it, thereby preventing the formation of air pockets in the loosely inserted part.

In the final step of press-fitting, since the leak prevention part is formed continuously to the press insertion part, the pipe is continuously guided from the press insertion part to the leak prevention part. For this reason, the press-fitting process is performed smoothly from the beginning to the end without any changes such as a sudden increase in frictional force during the process.

The inner periphery of the open end of the tube comes into pressure contact with the circumferential leakage prevention part, and this contact is made in the entire circumferential direction of the tube, so the adhesive will not leak to the open end of the tube after press-fitting is completed. .

Even if bending force is applied between the pipe and the fitting body after connection, stress will be concentrated on the pipe outside this part because the tip of the insertion part has an outward chamfer at the pressure insertion part. Since there are no cracks, it is possible to prevent cracks from occurring in the pipe.

[Brief explanation of drawings]

Fig. 1 is a front view showing an embodiment of the present invention, Fig. 2 is a right side view of Fig. 1, Fig. 3 is an enlarged cross-sectional view showing a connected state, and Fig. 4 is a front view showing an embodiment of the invention. It is an explanatory view of an example of application. DESCRIPTION OF SYMBOLS 1... Joint body, 2... Pipe, 3... Insertion part, 31... Pressure insertion part, 32... Loose insertion part, 4... Adhesive, 5... Gap, 6... Leakage prevention part.

Claims (1)

[Claims] 1 Comprising a joint body and an insertion part that protrudes from the joint body and is inserted into the end of the pipe, and the insertion part has a space between the pressure insertion part that presses against the inner periphery of the pipe and the inner periphery of the pipe. and a loose insertion part in which a gap for adhesive is formed at the insertion part, and the pipe is joined to the joint body by pressure contact in the pressure insertion part and adhesive in the loose insertion part, wherein the insertion part is The pressure insertion portion is formed by a continuous protrusion in the insertion direction, a plurality of pressure insertion portions are formed in the circumferential direction of the insertion portion, and the pressure insertion portions and the loose insertion portions are arranged alternately in the circumferential direction. In addition, the protrusion forming the pressure insertion part has a trapezoidal cross section, the width of the upper surface is significantly narrower than the width of the loose insertion part, and an outwardly chamfered part is formed at the tip of the insertion part. A circumferential leak prevention part that fits into the inner periphery of the open end of the pipe and prevents leakage of the adhesive is formed at an end close to the joint body so as to be continuous with the pressure insertion part, and the insertion part is A pipe joint characterized in that an inwardly chamfered portion is formed at the tip of a pipe to be inserted.