JPS6353015B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention has a protrusion on the outside, and the protrusion cannot be integrally molded, or it cannot be manufactured as a single item.
When it comes to integral molding for small-volume products, the mold shape is very complex and the production costs rise accordingly.It is difficult to manufacture resin products that reflect this in the product value, or to add protrusions to existing resin products. A technique applied when joining parts such as polyethylene resin, etc., to a main part made of thermoplastic resin and another part made of thermoplastic resin, by pressure welding with the joined part of both parts heated and softened. Concerning how to join.

[Conventional technology]

Conventionally, as a means of integrally joining thermoplastic resin members such as those mentioned above by heating and softening them, the joining parts of both members are heated and softened separately, and then the heating device is removed and the joining parts of both members are joined together. However, with this method, it is difficult to time the pressure welding according to the degree of heating, and the work needs to be completed in a short time, so both The mutual positioning of the members tends to be inaccurate, which not only reduces dimensional accuracy, but also makes the pressing force applied between the bonding surfaces uneven, making it difficult to obtain a reliable and uniform bonding force.

In order to eliminate such inconvenience, for example,
Applying the technology for joining pipes and cables shown in Japanese Patent Publications No. 51-1748 and No. 28-6376, a heating wire is embedded in the joint of both members, and the heating It is also possible to simultaneously soften both parts and then pressurize them with a tightening tool wrapped around the outer circumference to join them. It is difficult to apply this method only to structures where it is possible to apply pressure, and since pressure is applied using a tightening tool, it is impossible to apply pressure evenly at all points in the circumferential direction even to a tubular member. However, it is not possible to eliminate the above-mentioned non-uniformity of the bonding force caused by the non-uniformity of the pressure welding force applied between the bonding surfaces, and in addition, due to the uneven tightening action, the member may be heated and softened. There is also the risk of causing problems such as the device itself being easily deformed, so it is difficult to apply it to a means for joining deformable members, such as forming a protrusion on a part of the main member.

[Problem that the invention seeks to solve]

When welding and joining a main member made of a thermoplastic resin to another member, the present invention uses a thermoplastic resin that allows for accurate positioning of both members during pressure welding, and that makes it easy to equalize the bonding force over the entire joint surface. The purpose is to provide a method for joining resin members.

[Means for solving problems]

The technical means of the present invention taken to achieve the above object is to weld a separate thermoplastic resin member to a thermoplastic resin main member by pressure welding the joints of the two members together in a state where they are heated and softened. In the method of integrally joining, (a) a step of forming a tapered concave portion on the main member and forming a tapered convex portion on the separate member to be inserted into the tapered concave portion; (b) winding a heating wire that generates heat when energized around the joint surface of the outer periphery of the tapered projection of the separate member; (c) winding the tapered projection around which the heating wire is wound around the main energizing the heating wire while it is fitted into a tapered recess formed in the member;
a step of simultaneously heating and softening each bonding surface of both members; (d) a step of relatively pressing and moving the two members so that the softened bonding surfaces are brought into pressure contact with each other; ) was adopted.

[Effect]

As a result of taking the above technical measures, the following effects occur.

(i) When welding the two members together by pressure welding, both members are guided to a predetermined attachment position along a joining surface formed on a tapered surface. In other words, the joint surfaces formed in the tapered concave portion and the convex portion act as a guiding surface to a predetermined position as the relative position moves during pressure welding, and the guiding action with an alignment function due to this taper allows both members to Mutual positioning is performed accurately.

(ii) The joint surfaces are pressed together by the wedge action caused by the proximity of the tapered joint surfaces, and the mutual positions of both members are precisely determined and the pressure joints are made in a state where uneven loads are unlikely to occur. , there is less risk that the pressure welding force acting on each part of the joint surface will be extremely uneven, as in the case of pressure welding using a tightening tool such as an annular clamp fitting, and the pressure welding force applied to each part of the joint surface will be averaged over the entire joint surface. Easy to apply pressure force.

(iii) Since the heating wire is wound around the tapered joint surface, it is less heated when the joint parts are inserted into each other for pressure welding, compared to when the heating wire is wound around a simple cylindrical joint surface. It is easy to avoid lines shifting.

〔Effect of the invention〕

(a) From the effects of (i) and (ii) above, the relative positions of both parts can be determined with high precision, and unnecessary deformation due to pressure contact between the two parts can be determined, and the product can be produced as expected. It has the effect of being easy to create with high precision.

(b) From the effects of (i) and (ii) above, the joint surfaces of both members can be accurately positioned and the pressing force applied uniformly to the entire joint surface regardless of the shape of both members. By applying this, the welded joint surfaces can be easily joined firmly with uniform joining force.

(c) Due to the effect of (iii) above, uneven heating conditions on the bonding surfaces are less likely to occur, and in this respect as well, it is easy to obtain the desired strong bonding force.

〔Example〕

Examples of the method of the present invention will be described below with reference to the drawings.

Main member 1 made of thermoplastic resin as shown in Fig. 1
, an arbitrary three-dimensional shaped separate member 2 having a rod shape, a protrusion shape, or a foot made of the same thermoplastic resin,
For heat welding, a tapered recess 1A having a tapered joint surface 1B that becomes narrower toward the inner part is formed on the main member 1 side, and a tapered recess 1A is formed on the separate member 2 side to be inserted into the warped recess 1A. A heating wire 3 is formed on the outer surface of the joining surface 2B on the side of the tapered projection 2A, and the heating wire 3 generates heat and raises the temperature by energizing a heating resistance wire or the like in advance. is left bare and tightly wound in a spiral shape with the terminal portions 3A and 3A at both ends protruding.

Then, the tapered convex part 2A of the separate member 2, around which the heating wire 3 is wound, is inserted into the tapered concave part 1A as shown in FIG. By energizing the wire 3, both the bonding surface 2B on the tapered convex portion 2A side and the bonding surface 1B on the tapered concave portion 1A side are simultaneously heated and softened.

The heating temperature in this case is about 180°C for polyethylene resin.

Thereafter, both members 1 and 2 are moved relative to each other by pressing so that their softened surfaces are brought into pressure contact with each other, thereby welding and joining both members 1 and 2 into a state of integral tissue.

In addition, at the time of completion of joining, the terminal part 3
Although A and 3A are cut and removed, the other 3 portions of the heating wire remain buried within the thickness of the welded joint, which has the effect of further increasing the shear resistance and bending resistance of the joint.

Although the method of the present invention is most effective for joining polyethylene resins, it can of course be used for joining any other thermoplastic resins.

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[Brief explanation of drawings]

The drawings show an embodiment of the method for joining thermoplastic resin members according to the present invention, and FIG. 1 is a front view of the member before joining, FIG. 2 is a front view of the member during joining, and FIG. 3 is a front view of the member after joining is completed. It is a front view. 1...Main member made of thermoplastic resin, 1A...Tapered recess, 2...Separate member made of thermoplastic resin, 2
A... Tapered convex portion, 1B, 2B... Joint surface,
3... Heating wire.

Claims (1)

[Scope of Claims] 1. A main member 1 made of thermoplastic resin and another member 2 made of thermoplastic resin are joined together by pressure welding in a state where the joints of both members 1 and 2 are heated and softened. The method includes: (a) forming a tapered recess 1A in the main member 1, and forming a tapered recess 1A in the separate member 2;
a step of forming a tapered convex portion 2A to be inserted into the tapered concave portion 1A; (b) winding a heating wire 3 that generates heat when energized around the joint surface 2B of the outer periphery of the tapered convex portion 2A of the separate member 2; (c) energizing the heating wire 3 while the tapered convex portion 2A around which the heating wire 3 is wound is fitted into the tapered recess 1A formed in the main member 1; , each joint surface 1 of both the members 1 and 2
A step of simultaneously heating and softening B and 2B; (d) a step of relatively pressing and moving the members 1 and 2 so that the softened joint surfaces 1B and 2B are brought into pressure contact with each other; A method for joining thermoplastic resin members according to the step (d). 2. The method of joining thermoplastic resin members according to claim 1, wherein both members 1 and 2 are made of polyethylene resin.