JPS61242732A - Manufacture of valve case - Google Patents

Abstract

PURPOSE:To form a valve case in one-piece by plastic working only and to reduce a product price by extruding a pipe stock expanding one and the other ends of the pipe stock and forming a dowel on both the ends of the pipe, respectively. CONSTITUTION:A pipe stock 1 is extruded to form three flat planes 2 on the periphery of the pipe stock 1 and to correct the inside and outside diameters of the stock 1. An expanded part 3 is formed at the opposite open end to the side on which the flat planes 2 is formed; three dowels 4 projecting into the inside of the stock 1 and being to hold a valve seat are formed in the circular direction of the stock 1. An expanded part 5 is formed at the opposite open end to the expanded pat 3 and dowels 6 projecting into the inside of the stock 1 and being to hold the valve seat are formed. Then, dowels 7 determining the opening and closing position of the valve are formed at four positions around an optional one of the flat planes 2 in a non-expanded part 1a so that a valve case 8 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a method for manufacturing a valve case for a ball valve or the like, and particularly to a method for manufacturing a valve case from a pipe material by plastic working.

ψ) Prior art and problems Conventionally, valve cases for ball pulp and the like are formed by casting or forging.

When molding a valve case by casting, molten metal is injected into a mold that is compatible with the valve case, and after the molten metal is cooled and solidified, it is molded through a disassembly process, so the molding equipment becomes heavy-duty. There is also the problem that productivity is low, and finishing processing is required, resulting in a high-cost product.

In addition, the forming method by forging is more advantageous in terms of productivity and cost than the above-mentioned casting method, but unlike the half-sided casting method, the valve case cannot be integrally formed, that is, it cannot be closed together. A pair of matching sunken molds (lower mold and upper mold)
This method molds the product by inserting material between them and applying pressure, so if the valve case requires a cavity inside, it is molded in half, and these halves are joined together and welded. , must be joined by bolting, etc. This requires a joining process such as welding or bolting, which poses a problem of increasing the cost of the valve case.

Q1 Purpose of the Invention The present invention was made in order to solve the above-mentioned conventional problems, and it provides a valve case that enables integral molding of the valve case using only plastic working, thereby reducing the cost of the product. The purpose is to provide a manufacturing method.

(→Structure of the Invention The method for manufacturing a valve case according to the present invention includes an extrusion process in which a plurality of flat surfaces are formed along the longitudinal direction on the outer peripheral surface of a pipe material and the inner and outer diameters are corrected, and after passing through this extrusion process, a first pipe expansion step of expanding one end of the pipe material;
A first doweling step of forming a dowel for positioning and holding the valve seat that protrudes inward on the pipe material, a second expanding step of expanding the other end of the pipe material, and a second expanding step of expanding the other end of the pipe material. and a second dowel removal step of forming a dowel for positioning and holding the valve seat that protrudes inward on the enlarged pipe portion.

(g) Function In the present invention, a dowel for positioning and holding the valve body and valve seat, a pipe expansion section for joining the valve case and piping, a flat surface that functions as a reference surface, etc. are formed and the inner and outer diameters are corrected. Since the valve case can be molded using the same technology, it is now possible to mold the valve case from pipe material using only plastic processing.

(f) Examples of the invention Embodiments of the method of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the principle process sequence of the valve case manufacturing method according to the present invention, and is made of stainless steel.

An extrusion process in which a plurality of flat surfaces are formed on the outer periphery of the other metal pipe material 1 and the inner and outer diameters of the material are corrected, a first pipe expansion process in which one end of the pipe material that has undergone this extrusion process is expanded, and the resulting pipe A first doweling step in which a dowel for positioning and holding the valve seat is formed on the expanded side of the material, and a second doweling step in which the other end of the pipe material after the doweling is expanded.
a second doweling step in which a dowel for positioning and holding the valve seat is formed in the expanded portion of the pipe material after the pipe expansion, and a second doweling step in which a dowel for positioning and holding the valve seat is formed on the expanded portion of the pipe material after the doweling. This process includes a third doweling process of forming dowels around the periphery for positioning the valve body to open and close.

FIGS. 2 to 7 specifically show the relationship between the above-mentioned steps and the shape of the material formed in the pipe material corresponding thereto, and the details thereof will be explained below.

Figures 2(a) and 2) are external views of the pipe material 1 when a flat surface is formed on the outer peripheral surface of the pipe material 1 and the inner and outer diameters are corrected by forward extrusion processing in the extrusion process, and its B-
This is an enlarged cross-sectional view taken along line B. Flat surfaces 2 are formed at three locations with a phase difference of 120" in the circumferential direction of the pipe material 1, and extend parallel to the material axis from the middle part of the pipe material 1 toward one end. It has become.

When such a flat surface 2 is formed by forward extrusion, for example, a die having holes corresponding to three flat surfaces 2 is provided at one end, and a die shown in FIG. When the pipe material l shown in Fig. 2 is inserted and inserted with a plunger, three flat surfaces 2 are formed on the outer peripheral surface of the pipe material l as shown in Fig. 2 (al and (b)), and the inner and outer diameters of the pipe material l are The flat surface 2 is corrected and has small tolerances.Furthermore, this flat surface 2 is used as a reference surface in subsequent processes or to stabilize the seating of the valve case.

FIG. 3 shows an external view of the pipe material 1 that has been expanded in the first pipe expansion process. During the pipe expansion process, for example, the pipe material 1 with a flat surface formed thereon is opened from the flat surface formed end side. The tube expansion portion 3 is formed by inserting the container between containers having tube expansion holes and press-fitting a punch into the opening of the material opposite to the side where the flat surface is formed. This tube expansion portion 3 serves as a joint portion with a pipe when the valve is installed in a piping system or the like.

Figures 4(a) and 4(b) are external views of the pipe material that has been doweled in the first doweling process, and its B-
This is a cross-sectional view of B, in which three dowels 4 for positioning and holding the valve seat in this process are formed on the expanded pipe portion 3 side with a phase difference of 120° in the circumferential direction, and each dowel 4 is positioned inward of the pipe material 1. It stands out. Further, in actual processing of the dowel 4, a mandrel is inserted into the pipe material 1 from the expanded tube portion 3 side, and the corresponding outer periphery of the pipe material 1 is pressed with a punch.

FIG. 5 shows an external view of the pipe material expanded in the second pipe expansion step. In FIG. The expanded tube portion 5 is formed by inserting the punch into a container having a material having a diameter of 10 mm and press-fitting a punch by a predetermined amount into the opening of the material opposite to the expanded tube portion 3.

This tube expansion section 5 serves as a joint with piping, similar to the tube expansion section 3 described above.

In addition, FIGS. 6(a) and 6(b) are external views of the pipe material that has been doweled in the second doweling process, and its B
-A cross-sectional view taken along line B is shown. A dowel 6 for positioning and holding the valve seat in this process protrudes inward from the expanded tube portion 5,
It is formed close to the boundary between the expanded tube portion 5 and the non-expanded portion 1a continuous thereto, and has a diameter of 120 mm in the circumferential direction.
It has three phase waves of °. Further, the dowel 6 is formed by a mandrel and a punch inserted into the expanded tube portion 5.

FIGS. 7(a) and 7(b) show an external view of the pipe material that has been doweled in the third doweling process and a cross-sectional view taken along the line B-B. Four body opening/closing positioning dowels 7 are formed around any one flat surface 2 in the non-expansion portion 1a located in the middle of the pipe material 1. Further, the dowel 7 is formed by a mandrel and a punch that are inserted into the non-expansion portion la.

By going through each of the above steps, a valve case 8 having a shape as shown in FIG. 7(a) is formed.

FIG. 8 is a longitudinal cross-sectional view of the valve case in which a ball valve body and a valve seat are attached to form a ball valve.

When installing the valve body and valve seat, a valve rod insertion hole 9 is cut by cutting in the flat surface 2 surrounded by the four dowels 7, and then the inner end surface of the dowel 6 and the expanded tube portion 5 connected thereto are cut. The inner surface of the ring is slightly cut to form an engaging groove 11 that engages the retaining ring IO.

When installing the ball valve body 12 and the valve seats 13a, 13b into the valve case 8, first insert one ring-shaped valve seat support fitting 14a from the expanded tube portion 5 and into the non-expanded portion la. It fits watertight and engages with the dowel 4. Thereafter, one valve seat 13a is inserted, and the valve stem 15 is inserted and engaged into the hole 9 from inside the case, and the ball valve 12 is inserted and engaged with the valve stem 15 and the valve seat 13a. Next, insert the other valve seat 13b and attach it to the valve body 1.
2, and after fitting the other ring-shaped valve seat support metal fitting 14b from the outside into the non-expanded pipe part la watertightly and overlapping them, the retaining ring 10 is engaged in the engaging groove 11, and the spot It is fixed to the valve case 8 by welding or the like. As a result, the valve body 12 and the valve seats 13a, 13b are stably held within the valve case 8.

Further, after attaching a sealing material 16 such as a gland packing to the protruding base of the valve stem 15 that protrudes outside the valve case 8, the rotation regulating ring 17 is fitted onto the valve stem 15 and laminated on the sealing material 16. and tighten with nut 18. At this time, the handle (not shown) is also tightened and fixed together.

It goes without saying that the valve case molded by the method of the present invention can be applied not only to ball valves as shown in the above-mentioned usage examples, but also to plug valves, needle valves, and the like. In addition, if the rotation angle of the valve body is not specified, the third
It is possible to omit the dowel pressing process.

(G) Effects of the Invention As described above, according to the method of the present invention, a valve case such as a ball valve can be integrally formed by extruding a pipe material, and only by plastic processing such as pipe expansion and doweling. It has the advantage of being easy to mold, enabling mass production, and significantly reducing costs.

[Brief explanation of the drawing]

FIG. 1 is a Pronk diagram showing the principle process according to the method of the present invention.
Figure 2 (a), (b), Figure 3, Figure 4 (a), (
b). Figure 5, Figure 6 (al, (b) and Figure 7 (a),
(b) is an explanatory diagram for a specific manufacturing process showing the relationship between each step in FIG. 1 and the corresponding material shape formed on the pipe material, and FIG. 8 is an explanatory diagram for manufacturing by the method of the present invention. FIG. 2 is a longitudinal cross-sectional view of a ball valve constructed by attaching a ball valve body and a valve seat to a valve case manufactured by the method. 1... Pipe material, 2... Flat surface, 3°5...
・Pipe expansion part, 4.6... Dowel for positioning and holding the valve seat, 8
...Valve case. Patent applicant: AIDA ENGINEERING CO., LTD.
figure

Claims (1)

[Claims] an extrusion step in which a plurality of flat surfaces are formed along the length of the outer peripheral surface of the pipe material and the inner and outer diameters are corrected; a first tube expansion step in which one end of the pipe material after this extrusion step is expanded; A first doweling step of forming a dowel for positioning and holding the valve seat that protrudes inward on the pipe material, a second expanding step of expanding the other end of the pipe material, and a second expanding step of expanding the other end of the pipe material. and a second dowel removal step of forming a dowel for positioning and holding the valve seat that protrudes inward in the expanded tube portion.