JP3128110B2 - Ball valve and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ball valve having an integral synthetic resin body used for piping of water, oil, gas and the like, and a method of manufacturing the same.

[0002]

2. Description of the Related Art The point where the spherical outer surface of a ball of a ball valve and the inner diameter surface of a flow passage hole intersect is an acute angle, since the surface of the body seat is damaged when the ball is rotated. Is done. The ball 21 shown in the partial cross-sectional view of FIG. 6 is an example of the inflection surface 21 in which both the spherical outer surface 21a and the inner diameter surface 21c of the passage hole 21b are rounded.
It is tied with d.

When the body 22 is injection-molded integrally using such a ball 21 as a part of a core, it is necessary to extract the core to the left and right after the molding, and the passage hole 22 is formed in the core.
A portion larger than the diameter of a cannot be provided inward from a portion corresponding to the flow path hole 22a, and in FIG. 6, the portion outside the two-dot chain line 21e shown by extending the spherical outer surface 21a of the ball 21 as it is is shown. The substantially triangular portion 21 f of the other side is also formed as a part of the body 22. In this case, the ball 21 cannot rotate.

For this reason, at least 21f in FIG.
It is necessary not to form a part of the body 22 on a part of the body 22. A method of forming the part 21f with a casting material such as an abrasive powder and removing the casting material such as the abrasive powder after forming the body 22 by washing out the casting material such as the abrasive powder And so on. However, with this method, it is troublesome to reliably remove the casting material such as abrasive powder, and there is a problem that the remaining material causes a failure.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a ball valve which solves the conventional problems, and a body made of a synthetic resin does not hinder the rotation of the ball, and the molding of the body can be performed. In the method, in particular, treatment after molding can be easily performed.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a ball valve having a synthetic resin body integrally formed by injection molding using a ball and a stem as a part of a core. Te, and the spherical outer surface of the ball when fully open baud
The part position of the body of the flow path hole facing the varying curved surface connecting the inner surface of the through hole of the Le, so that the resin is not filled at the time of injection molding
A circumferential groove was provided in a part of the core .

A synthetic resin body integrally formed by injection molding using a ball and a stem as a part of a core, and having a shape connecting an outer surface of a sphere and an inner surface of a through hole of the ball when the ball is fully opened. faces the curved surface, and both sides of the body of the channel a core portion in a circumferential groove formed in the hole, the through hole of the core portion can be decomposed ball size that taken out after molding of the body from the body of the flow path hole To form a through-hole in the ball and injection molding. In this case, the core is preferably made of metal.

[0008]

Since the present invention is constructed as described above, first, the ball valve of the present invention is adjacent to a synthetic resin body ball which is integrally molded by using a ball and a stem as a part of a core. In the portion of the flow path hole that is formed, a circumferential groove is provided in a portion facing the inflection surface connecting the spherical outer surface of the ball and the inner peripheral surface of the through hole when fully opened, so that the body does not hinder the rotation of the ball, In addition, since an inflection surface is formed between the spherical outer surface of the ball and the inner surface of the through hole so as not to be an acute angle, the seat surface of the body is not damaged when the ball rotates.

Next, in the above-mentioned ball valve, a metal core having a portion corresponding to a circumferential groove is attached to both sides of a through hole of the ball, and the ball is used as a part of the core. Therefore, the circumferential groove can be reliably formed in the body. Further, after molding, the core portion is disassembled into small pieces and can be taken out from the flow passage hole of the body, and there is no need to use a casting material such as abrasive powder.
No special treatment such as cleaning is required after molding, and there is no risk of failure due to poor cleaning.

[0010]

FIG. 1 is a longitudinal sectional view showing an embodiment of a ball valve according to the present invention.
a ball having b, a stem 3 for rotating the ball 2,
Reference numeral 4 denotes a body, and the ball valve 1 has a body 4 made of synthetic resin, which is integrally molded by using the ball 2 and the stem 3 as a part of a core. The body 4 has a circle formed in the flow path hole 4a of the body 4 facing the inflection surface 2d connecting the spherical outer surface 2a of the ball 2 and the inner diameter surface 2c of the through hole 2b in the fully opened state shown in FIG. A peripheral groove 4b is provided. FIG. 2 is an enlarged partial sectional view showing this portion of FIG. 1 in an enlarged manner.

FIG. 3 is a longitudinal sectional view showing one embodiment of the method of manufacturing a ball valve according to the present invention, wherein core portions 13, 14 and bolts 11 and nuts 12 are fastened to the left and right sides of the ball 2, respectively. The core portion 14 mounted on both sides of the through hole 2b of the ball 2 has a portion having a shape corresponding to the circumferential groove 4b shown in FIGS. Reference numerals 16 and 17 denote outer dies.
The synthetic resin was injected into a space 18 formed by combining the stems 6 and 17 with the stem 3, the ball 2 and the above-mentioned cores mounted on both sides of the ball 2 by tightening, as shown in FIG. A body 4 is formed. The core parts 13, 1
Each of the outer molds 4 and 15 and the outer dies 16 and 17 is made of metal.

FIG. 4 shows the right core portion 1 shown in FIG.
FIG. 4 is a side view of the core 4 as viewed from the right side, and
a, 14b, 14c, and 14d, each of which has a size that can be taken out of the flow passage hole 4a of the body 4. For example, small pieces 14b and 14
The length L in the drawing d is the diameter d of the flow passage hole 4a shown in FIG.
It is formed shorter. The small pieces 14a, 14
The inner peripheral surfaces 14e of b, 14c and 14d are in contact with the outer peripheral surface 13a of the small diameter portion of the core portion 13, and the outer peripheral surface 14f of the boss portion is positioned by the step portion 15a of the core portion 15, a spigot portion or other means.

Further, these core parts are 14a, 14b,
The outer ends 14g of the balls 2 of 14c and 14d which are in contact with the spherical outer surface 2a of the ball 2 may have an acute claw shape as shown in FIG.
Further, any structure may be used as long as it is in contact with the spherical surface of the ball 2. FIG. 5 is an enlarged partial cross-sectional view of FIG.
Positioning of a, 14b, 14c and 14d and outer end 14g
Of the ball 2 in contact with the spherical outer surface 2a.

Next, the operation will be described based on the embodiment shown in FIGS. Ball valve 1 of the present invention
Is formed by integrally injection-molding the body 4 using the ball 2 and the stem 3 as a part of the core. When the ball valve 1 is fully opened as shown in FIG. Spherical outer surface 2a of ball 2 and inner diameter surface 2c of through hole 2b
Since the circumferential groove 4b is provided in the portion of the passage hole 4a of the body 4 facing the inflection surface 2d connecting the body 4 and the body 4, the body 4 does not hinder the rotation of the ball 2. Also, the spherical outer surface 2 of the ball 2
Since the curved surface 2d is formed between the a and the inner diameter surface 2c of the through hole 2b and formed in an arc shape, the seat surface of the body 4 is not damaged when the ball 2 rotates.

Next, the ball valve 1 is inserted into the circumferential groove 4b.
A metal core portion 14 having a portion corresponding to the shape of the core 4 is mounted on both sides of the through hole 2b of the ball 2, and a synthetic resin is used as a part of the core to form the body 4 by injection molding. The circumferential groove 4b can be reliably formed in the body 4. Further, after molding, the core portion 14 is
4b, 14c, and 14d, first take out 14a and 14c from the flow passage hole 4a of the body 4, and then take out 14a and 14c.
b and 14d can be extracted. In addition, there is no need to use a casting material such as abrasive powder, no special processing such as cleaning is required after molding, and there is no risk of failure due to poor cleaning.

[0016]

As described above, in the ball valve of the present invention, even if the ball is provided with a curved surface connecting the spherical outer surface and the inner diameter surface of the through hole, the ball is formed by injection molding as a part of the core. Because the circumferential groove is formed in the body formed by this, there is no part that hinders the rotation of the ball, so that the opening and closing operation can be performed smoothly, and the rotation of the ball damages the seat part of the body I can't do that.

Further, the method for manufacturing a ball valve of the present invention uses a metal core portion to form a circumferential groove.
A circumferential groove of precisely dimensioned shape is created. Further, this core portion can be disassembled into small pieces and can be taken out from the flow passage hole of the body, so that the work is easy. Further, since no casting material such as abrasive powder is used, no special treatment such as cleaning is required after the molding of the body, and no trouble is caused.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of a ball valve of the present invention.

FIG. 2 is an enlarged partial sectional view of FIG.

FIG. 3 is a longitudinal sectional view showing one embodiment of a method of manufacturing a ball valve according to the present invention.

FIG. 4 is a side view of the core portion 14 of FIG.

FIG. 5 is an enlarged partial sectional view of FIG. 3;

FIG. 6 is a partial sectional view showing the structure of a conventional ball valve.

[Explanation of symbols]

 Reference Signs List 1 ball valve 2 ball 2a spherical outer surface 2b through hole 2c inner diameter surface 2d inflection surface 3 stem 4 body 4a flow passage hole 4b circumferential groove 14 core portion 14a, 14b, 14c, 14d small piece of core portion

Claims (3)

(57) [Claims] 1. A ball valve having a body made of synthetic resin and integrally injection-molded using a ball and a stem as a part of a core, wherein the spherical outer surface of the ball and the inner diameter surface of a through hole of the ball when fully opened. preparative the part position of the body of the flow path hole facing the varying curved surface connecting, so that the resin is not filled at the time of injection molding
A ball valve characterized in that a circumferential groove is provided in a part of the core . 2. A ball valve having a synthetic resin body which is injection-molded integrally using a ball and a stem as a part of a core, wherein when fully opened, a spherical outer surface of the ball and an inner diameter surface of a through hole of the ball are provided. facing a variable curved surface connecting the bets, and a core portion corresponding to a circumferential groove formed in the flow path hole of the Bode <br/> over, the magnitude that taken out from the body of the flow passage holes after molding of the body min A method for manufacturing a ball valve, wherein the ball valve is mounted on both sides of a through hole of a ball so that the ball valve can be unloaded. 3. The method according to claim 2, wherein the core portion is made of metal.