JP2707176B2 - Ball valve - 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 a ball for opening and closing a flow passage therein.

[0002]

2. Description of the Related Art As shown in FIG. 6, a conventional ball valve has a through hole 03 in a body 02 having flow paths 01 on the left and right.
Is rotated by the lever 05, and the flow path 0
1 is closed and opened.

[0003] One of the body 02 is formed with a flow passage in which a male screw 06 for a cap nut is threaded, and the other is formed with a female screw portion 07.

[0004] Reference numeral 08 denotes a body cap. Both ends of the body cap 08 are threaded with male threads by a screw cutter.
Is screwed into the female screw portion 07 of the body 02 via a packing 010 for sealing.

[0005] Reference numeral 011 denotes a seat ring that presses the ball 04 at the peripheral edge, and 012 denotes an O-ring that seals a connecting pipe inserted into the flow path 01. In the ball valve assembled in this manner, the male screw portion 06 for the cap nut is exposed at both ends, and the connection pipe can be attached by screwing the cap nut into the male screw portion 06 for the cap nut. .

[0006]

However, in the above-mentioned conventional body cap 08, both ends are threaded. When threading with a screw cutter, the gripping portion, in other words, the body cutter is fixed at the time of threading. Is difficult to secure. In other words, after one threading is completed, when performing the other threading, the threaded end portion cannot be gripped as a gripping portion, and it is difficult to secure a gripping portion for machining.

[0007] Therefore, the applicant has devised a manufacturing process in which only one of the two external thread portions is threaded with a screw cutter, and the other external thread portion is formed in a casting process.

This will be described with reference to FIGS. FIG. 7 shows a manufacturing process of the body cap 08, in which wax is press-fitted into a mold of both halves 013 made of metal to make a wax model 014 (A). Next, sanding is performed inside and outside of the wax model 014 (b) to form a sand mold 015 (c), and the wax inside is melted by heating and dewaxed.
Is fired, and the casting metal 0
By casting (16) and breaking the mold 015 (there is no male screw part 09 for one of the machined cap nuts)
The body cap as shown in FIG. 8 is completed.

However, at the time of forming the wax model 014, since a mold is made by combining at least two half molds 013, burrs 017 enter the center of the wax model 014 so as to bisect the wax model. There was a problem that it took time to remove the burr 017. Further, due to casting distortion generated at the time of casting, the male screw portion 09 does not become a perfect circle, and some post-processing is required.

According to the present invention, the male screw portion formed at the time of casting can be screwed into the female screw portion of the body of the ball valve as it is without machining , and the sealing property is ensured.
And easy to remove the packing when disassembling the valve
It is to provide a ball valve having a body cap that can be easily operated.

[0011]

In order to achieve the above object, a ball valve according to the present invention has a female thread portion formed at one end of a body in which a ball for opening and closing a flow path is provided. In a ball valve formed by screwing a male screw portion formed at one end of a cap, a body cap is cast, and the body cap has one end of a body.
The male screw part is formed on the flange and the tip that comes in contact with
The diameter of the root of the male thread between the male thread and the flange
Annular recess for packing fitting
The male thread is symmetrical with respect to the center line of the flow path.
At least two thread cuts are provided
This thread cut portion is continuous into the annular concave portion.
It is characterized by being extended .

[0012]

The male thread formed at one end of the body cap is provided with at least two thread cuts at positions symmetrical with respect to the center line of the flow path. The burr portion matches the thread cut portion, and the burr of the male screw portion does not hinder the screwing of the body cap into the female screw portion of the body. Further
Then, the burr part was removed by thread cutting
Fluid leaks easily from there, but this male screw part
Between the male screw root and the flange behind it
An annular recess is formed in the
The sealability of the rim is sufficiently ensured. In addition, the annular
Since the thread cut portion extends to the recess,
Easily remove this packing with a spatula using the
There is an excellent effect that it can be removed.

[0013]

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

FIG. 1 shows a ball valve according to the present invention. A ball 4 having a through hole 3 in a body 2 having a flow path 1 on the left and right is rotated by a lever 5 to close the flow path 1. ,
It is designed to open. On one side of the body 2, there is formed a flow path in which a male screw 6 for a cap nut is screwed, and on one side, a female screw portion 7 is formed.

Reference numeral 8 denotes a body cap. An external thread portion 6 for a cap nut is threaded at one end of the body cap 8 by a screw cutter. One of the external thread portions is a female thread of the body 2. It is screwed into the part 7 via a packing 10 for sealing.

Reference numeral 11 denotes a seat ring that presses the ball 4 at the peripheral edge, and 12 denotes an O-ring that seals a connection pipe inserted into the flow path 1. The O-ring protrudes annularly at substantially the center of the body cap 8. It is fitted in an annular concave portion 14 formed in a constricted shape between the flange 13 and the male screw portion 9.

In the ball valve assembled as described above, the male screw portion 6 for the cap nut is exposed at both ends, and the connecting pipe is formed by screwing a cap nut (not shown) into the male screw portions 6 for the cap nut. Each can be attached.

FIGS. 2 and 3 show the body cap removed from the ball valve, and the male screw portion 9 has a thread cut portion 15 as if the thread was cut off.
Are formed at four locations, up, down, left and right. This is because the burrs 21 generated at the time of casting the body cap 8 are aligned with the thread cut portion 15, and the burrs 21 of the male screw portion 9 hinder the screwing of the body cap 8 into the male screw portion 7 of the body 2. This is so as not to be. Further, deformation of the male screw portion 9 due to thermal distortion generated at the time of casting is absorbed by the thread cut portion 15, and a substantially perfect circle is maintained. It is sufficient that at least two thread cut portions 15 are provided on the male screw portion 9 at positions symmetrical with respect to the center line of the flow path, but at least four at equal intervals to maintain a perfect circle. Is more effective.

The above-mentioned packing 10 has an annular recess 14 formed between the flange 13 and the male screw portion 9.
However, since the thread cut portion 15 is formed as shown in FIG. 3, the degree of exposure of the packing 10 increases at the position of the thread cut portion 15 when viewed from the front.

Therefore, when the packing 10 is replaced, as shown in FIG.
The packing 10 can be easily removed by inserting it into the opening 5 and expanding it, which is superior to the conventional product.

FIG. 4 shows the body cap 8 immediately after casting.
Of the seat ring 11, the packing 1
0 and the O-ring 12 are not attached, and the male screw 6 for the cap nut is not threaded.

In this body cap 8, as shown in FIG. 5, three flat portions 18 are formed at equal intervals in a portion corresponding to the male screw portion 9 in each mold half 17 of the mold.
In particular, a half flat surface 18 is formed on each of the joining surfaces 19 of the two mold halves 17, and the structure is such that when the mold halves 17 are joined, one flat surface 18 is formed. Therefore, when the wax model 20 is formed using this mold, four thread cut portions 15 are formed on the male screw portion 9 of the wax model 20 as if the threads were cut off.

Therefore, when a cast product is made using the wax model in the same process as the conventional one, the body cap 8 shown in FIG. 4 is completed.

Thereafter, the body cap 8 is subjected to a screw cutting process using a screw cutter to form the male screw portion 6 for the cap nut, but since the thread cut portion 15 is formed vertically, these flat portions are formed. The end face is sandwiched from above and below, and functions as a grip portion that does not damage the thread of the male screw portion 9. For this reason, the threading of the male screw portion 6 for the cap nut is facilitated, and more secure fixing is possible by using four locations as the holding portions.

The ball valve is completed by screwing the body cap 8 as shown in FIG. When the ball 4 rotates, water leaks into the body 2 but the packing 1
Zero ensures that water leakage is prevented. Also, when disassembling and assembling this ball valve underground for some reason, sand or mud enters the threaded portion of the male screw portion 9 and the female thread portion 7, but the thread cut portion 15 causes the threaded portion to be screwed. A space is formed in the portion, and mud and sand accumulate in this space, and the occurrence of galling during screwing is reduced.

The casting mainly targeted in the present invention is a stainless alloy, and both the body and the body cap are stainless alloy castings. Therefore, the female screw portion 7 of the body 2 is also formed at the time of casting, and no machining such as a screw cutter is used.

The present invention is not limited to the above embodiment, and the casting may be a stainless steel casting, a bronze casting, or a ductile cast iron. Furthermore, the present invention includes all aspects of the embodiments that can be achieved by those skilled in the art when embodying the spirit of the invention.

[0028]

The present invention has the following effects.

The male screw formed at one end of the body cap is provided with at least two thread cuts at positions symmetrical with respect to the center line of the flow path. The burr portion matches the thread cut portion, and the burr of the male screw portion does not hinder the screwing of the body cap into the female screw portion of the body. Furthermore, the above-mentioned burrs are removed by thread cutting.
This makes it easier for fluid to leak out of it,
The root of the male screw is located between the male screw and the flange behind it.
An annular recess is formed on the inner side, and packing is fitted here
Therefore, the sealing property is sufficiently ensured. in addition,
A thread cut portion extends to the annular recess.
Use this cut to remove this packing with a spatula
It has an excellent effect that it can be easily removed.

[0030]

[Brief description of the drawings]

FIG. 1 is a partial side sectional view of a first embodiment of the present invention.

FIG. 2 is a perspective view of a body cap used in the embodiment of FIG.

FIG. 3 is a front view of FIG. 2;

FIG. 4 is a perspective view of a cast product of a body cap.

FIG. 5 is an explanatory view when a wax model serving as a prototype of a body cap is manufactured.

FIG. 6 is a partial side sectional view of a conventional ball valve.

FIG. 7 is a perspective view of a conventionally used body cap.

FIG. 8 is a manufacturing process diagram of a conventional body cap.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flow path 2 Body 3 Through-hole 4 Ball 5 Lever 6 Male screw for cap nut 7 Female screw part 8 Body cap 9 Male screw part 10 Packing 11 Seat ring 12 O-ring 13 Flange 14 Annular concave part 15 Thread cut part 16 Knife (Spatula) 17 Half mold 18 Flat surface 19 Joining surface 20 Wax model 21 Burr

Claims (1)

(57) [Claims] A ball formed by forming a female screw portion at one end of a body in which a ball for opening and closing a flow path is provided, and screwing a male screw portion formed at one end of a body cap into the female screw portion. In the valve, the body cap is cast,
The body cap has a flange that abuts one end of the body.
A male screw part is formed at the tip and the tip thereof, and the male screw part
The gap between the flange and the flange should be inside the diameter of the root of the male thread.
An annular recess for packing fitting is formed so that
The threaded portion should be slightly symmetrical about the center line of the flow path.
At least two thread cuts are provided.
The mountain cut portion extends continuously into the annular concave portion.
Ball valve according to claim Rukoto.