JPH10205637A - Resin valve and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively bring a function as a valve by maintaining the joining strength and dimensional accuracy at thermal crimping and to provide this resin valve economically excellent. SOLUTION: When a resin body 1 and a resin cap 12 are fusedly joined together, it is recommented that, before their joining, a plate-like heater 21 is interposed between both joined surfaces 22 and 23 of the body 11, while the body 11 and two fitting parts 24 and 25 of the cap 12 are fitted with each other, and a clearance H between a tip face 26 of this fitting part 24 and a contact surface 27 should be set to that of a nearly totalling portion between thickness W of the heater 21 and depth necessary for thermal crimping, and in time of joining, both these joined surfaces 22 and 23 are heated into fusion by the heater 21, then they are joined together under pressure, and successively this pressure contact is released and simultaneously the heater 21 is removed away, while the joined surface 22 of the body 11 and the joined surface 23 of the cap 12 are heated into crimping, making the tip face 26 of the fitting 24 and the contact surface 27 come into contact with each other, and thus a valve body 20 is made so as to be manufactured by joining the body 11 and the cap 12 together by means of fusion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin valve and a method of manufacturing the same, and more particularly, to a structure in which a valve body of a synthetic resin ball valve made of a polyolefin or the like is joined by heating and pressing and a method of manufacturing the same.

[0002]

2. Description of the Related Art For example, in a ball valve, the tightness and operability in the valve are maintained by a ball pressed against a ball seat. By the way, resin valves are often used as valves with excellent corrosion resistance. However, when welding and joining the components of the valve, a plate-shaped heater is interposed between the joint surfaces of the body and the cap, and the heat and pressure is applied. Then, the heater is removed and, at the same time, pressure welding is performed to manufacture the valve body. Therefore, various proposals have conventionally been made for resin valves in order to maintain the dimensional accuracy of the valves (see JP-A-59-103090, JP-B-61-34375, etc.).

FIG. 9 is a partial cross-sectional view showing a conventional example of a synthetic resin ball valve. According to FIG. 9, the joining surfaces 3 and 4 of the body 1 and the cap 2 are of a flat type, and the joining burrs 5 are provided. , 6 are formed inside and outside, and the seat retainer 7 is used to fix the seat 8 and prevent the centering of the body 1 and the cap 2 and the dimensional error of the pressure bonding.

[0004]

However, when the above-mentioned conventional method is applied to a valve such as a ball valve by heating and pressure bonding, a dimensional error occurs because the bonding surface is bonded in a flat state, resulting in a dimensional error of the valve. It is clear that the operation and the sealing performance are adversely affected. In addition, if this joining is performed in the final step of the valve, and if a dimensional error occurs due to joining, the valve itself needs to be discarded. As a result, the product yield decreases and the overall cost increases. There is a problem that it may be a factor of Further, the ball valve of the conventional example shown in FIG. 9 uses the seat retainer 7 for centering, and therefore is indirect. .

[0005] The present invention has been developed in view of the above-mentioned problems, and an object of the present invention is to maintain the bonding strength and dimensional accuracy at the time of thermocompression bonding so as to effectively exhibit the function as a valve. Another object of the present invention is to provide a resin valve excellent in economy.

[0006]

Means for Solving the Problems To achieve the above object, a first means of the present invention is to provide a resin valve for forming a valve body by heat-pressing a body and a cap. Is provided with a joint surface to be heated and press-fitted, a fitting portion to be fitted between them, and a contact surface at a distal end position of the fitting portion and at a position not affected by the heat and pressure bonding. And maintain dimensional accuracy. In this case, the separation distance H between the abutment surface of the body and the cap before joining is a distance substantially equal to the thickness W of the heater interposed on the joining surface and the depth required for thermocompression bonding. In addition, a joining groove formed in an appropriate shape such as unevenness or a dovetail groove is provided in a part of the joining surface. The valve is preferably a ball valve in which a body and a cap are heat-pressed and a ball having a through-hole inside the valve body is opened and closed via a ball seat.

[0007] A second means of the present invention is that, when a resin body and a resin cap are fused and joined, a heater is interposed between a joint surface of the body and a joint surface of the cap before joining, and a heater is interposed between the body and the cap. The fitting portion of the cap is fitted, and the separation distance H between the distal end surface and the contact surface of the fitting portion is a distance substantially equal to the total thickness of the thickness W of the heater and the depth required for thermocompression bonding. Occasionally, the joint surface is heated and melted by a heater to make pressure contact, then the pressure contact is released and the heater is removed at the same time, and both are heated and pressed to bring the tip end surface of the fitting part into contact with the contact surface to melt the body and cap. The valve body was manufactured by being attached and joined.

[0008]

FIG. 1 to FIG. 8 show an example in which an embodiment of the present invention is applied to a ball valve. FIG. 1 is a cross-sectional view of a floating ball valve using a rubber sheet 10. Reference numeral 11 denotes a synthetic resin body, and 12 denotes a synthetic resin cap.
And the cap 12 are joined to form the valve body 20.
Reference numeral 13 denotes a ball having a through hole 14, reference numeral 15 denotes an outer ring, reference numeral 16 denotes a stem, reference numeral 17 denotes a cover, and reference numerals 18 and 19 denote O-rings.

The resin used for the synthetic resin valve body 20 is, for example, a halogen-containing resin such as a polyvinyl chloride resin, a polyvinylidene chloride resin, a polyvinylidene fluoride resin, a high-, medium-, or low-density polyethylene resin. Polyolefin resin such as linear lowden polyethylene resin and polypropylene resin, polystyrene resin, polyacetal resin, ABS resin, acrylic resin, polycarbonate resin, polysulfone resin, polyamide resin, polyphenylene oxide resin, polyphenylene sulfide resin, polyarylate resin, polyethylene terephthalate resin, etc. Thermoplastic resins are preferred and are arbitrarily selected depending on the implementation.

In the ball valve shown in FIG. 1, the fluid is sealed with the rubber sheet 10 attached to the cap 12 when the fluid flows from the body 11 to the cap 12, and conversely when the fluid flows. Body 11
The fluid is sealed with the rubber sheet 10 on the side. The floating ball valve in FIG.
The ball 13 moves in parallel with the stem 16 to the downstream side to compress the rubber sheet 10 to seal the fluid. Since the rubber sheet 10 cannot support the fluid force applied via the ball 13, if the cap 12 is located downstream in a sealed state, the ball surface 13 a of the ball 13
Is pressed against the cap contact surface 12a of the cap 12,
The rubber sheet 10 located on the downstream side is also compressed by the movement of the ball 13 and seals the fluid.

As described above, when the body 11 and the cap 12 are fusion-bonded, in order to keep the gap within the design tolerance after the bonding, if the surface to be bonded is only a flat surface as in the related art,
It has been confirmed that the joint strength and the tolerance are affected.

Therefore, the present invention employs the following structure and method. FIG. 2 shows a state of heating before joining. The heater 21 used for heating has a thickness of W. After joining the joining surfaces 22 and 23 of the body 11 and the cap 12, the heater 21 is heated to a depth necessary to have a predetermined strength. In the body 11 and the cap 12 to be joined, as shown in FIG. 2, fitting portions 24 and 25 are provided, and a distal end surface 26 of the fitting portion 24 and a contact surface 27 are formed. The distance between the front end surface 26 and the contact surface 27 is H, which is the sum of the thickness W of the heater 21 and the heating depth required for thermocompression bonding. Therefore, after heating, the heater 21 is removed and H = 0, that is, pressure bonding is performed until the distal end surface 26 and the contact surface 27 come into contact with each other.
Confirmed that the bonding burrs 28 were exposed to the outside and that sufficient strength was obtained.

As described above, the body 11 and the cap 12 are provided with the fitting portions 24 and 25, the distal end surface 26 and the contact surface 27, respectively.
Is provided, so that the ball 13 and the valve body 2
It is easy and reliable to secure the gap with zero, and the joining operation can be performed reliably without the necessity of managing the joining burr 28 or the like. Further, the present invention relates to the sheet 10
Is not related to the fusion bonding, the seal is not directly affected at the time of bonding, and the function of the valve is not affected at all.

Further, as shown in FIGS. 3 to 8, by providing uneven joining grooves 29, 30 and dovetail-shaped joining grooves 31, 32 in a part of the joining surfaces 22, 23, FIG. Although the joining burrs 28 are formed only on the outside, according to the present embodiment, the joining burrs are engaged only with the joining grooves 29, 30, 31, and 32 without leaving the joining burrs only on the outside at the time of the heat-compression bonding. At the same time, mechanical strength is also added, and it exerts remarkable functions.

Next, the manufacturing method according to the present invention will be described in detail. When the resin body 11 and the resin cap 12 are fusion-bonded, the bonding surface 2 of the body 11 is bonded before the bonding.
Plate-shaped heater 21 between the joint surface 2 and the joint surface 23 of the cap 12
And the fitting portions 24 and 25 of the body 11 and the cap 12 are fitted together. The distance H between the distal end surface 26 of the fitting portion 24 and the contact surface 27 is equal to the thickness W of the heater 21. At the time of joining, the joining surfaces 22, 23 are heated and melted by the heater 21 for pressure bonding, and then the heater 21 is removed at the same time as the pressure contact is released, and the body 11 is joined. The valve body 20 is manufactured by heat-pressing the joining surface 23 of the surface 22 and the cap 12 to bring the tip end surface 26 of the fitting portion 24 into contact with the contact surface 27 to fuse and join the body 11 and the cap 12. I do.

The above embodiment has been described with reference to a ball valve. However, the present invention is not limited to this, and can be applied to other valves. For example, the structure of the present invention and its manufacturing method can be applied to the point of final joining between the body and the upper lid, and the same operation and effect can be obtained. In addition, a trunnion ball valve side entry type, top entry Of course, it can be applied to a mold.

[0017]

As is evident from the above, according to the present invention, the bonding strength and dimensional accuracy can be reliably ensured at the time of thermocompression bonding, so that the function as a valve can be exhibited effectively. It is possible to propose a resin valve having a large practical value and a method for manufacturing the same, which can contribute to cost reduction of the product and is excellent in economic efficiency.

[Brief description of the drawings]

FIG. 1 is a sectional view of a resin ball valve according to the present invention.

FIG. 2 is a partially enlarged cross-sectional view in which a heater before bonding in FIG. 1 is interposed.

FIG. 3 is a partial cross-sectional view showing a valve before joining.

FIG. 4 is a partial cross-sectional view showing the valve after joining in FIG. 3;

FIG. 5 is a partial cross-sectional view showing a valve before joining.

FIG. 6 is a partial cross-sectional view showing the valve after joining in FIG. 5;

FIG. 7 is a partial cross-sectional view showing a valve before joining.

FIG. 8 is a partial cross-sectional view showing the valve after joining in FIG. 7;

FIG. 9 is a partial sectional view of a conventional resin ball valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Rubber sheet 11 Body 12 Cap 13 Ball 14 Through hole 15 Outer ring 16 Stem 17 Cover 18, 19 O-ring 20 Valve main body 21 Heater 22, 23 Joining surface 24, 25 Fitting part 26 Tip surface 27 Contact surface 28 Joint burr 29, 30, 31, 32 Joint groove

Claims (5)

[Claims] 1. A resin valve for forming a valve body by heat-pressing a body and a cap, wherein the body and the cap have a joint surface to be heat-pressed, a fitting portion for fitting the both, and this fitting portion. A resin valve characterized in that a contact surface is provided at a position of a tip end thereof and at a position not affected by thermocompression bonding so that sufficient bonding strength and dimensional accuracy are maintained during thermocompression bonding. 2. The separation distance H between the contact surface of the body and the cap before joining the cap is substantially the total distance of the thickness W of the heater interposed on the joining surface and the depth required for thermocompression bonding. 1
The resin valve as described. 3. The resin valve according to claim 1, wherein a part of the joint surface is provided with a joint groove having an appropriate shape such as an unevenness or a dovetail groove. 4. The resin valve according to claim 1, wherein the body and the cap are heat-pressed to each other, and a ball having a through hole inside the valve body is opened and closed via a ball seat. 5. When a resin body and a resin cap are fusion-bonded to each other, a heater is interposed between a joint surface of the body and a joint surface of the cap before the joint, and a fitting portion between the body and the cap is fitted. The separation distance H between the distal end surface of the fitting portion and the contact surface is set to a distance that is approximately the total of the thickness W of the heater and the depth required for thermocompression bonding. Heat and melt and press-contact, then release the press-contact and remove the heater at the same time, and heat-press the two to bring the tip end surface of the fitting part into contact with the contact surface to fuse and join the body and cap to form the valve body. A method for manufacturing a resin valve, characterized in that the valve is manufactured.