JPS636337B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a so-called compact ball valve in which a ball and a ball seat are embedded inside the valve body when the valve body is formed.
When manufacturing a compact ball valve, a ball 3 and ball seats 4, 4 are used as shown in FIG.
Conventionally, the inner peripheral surfaces of the end surfaces of the ball seats 4, 4 were pressed by the core molds 1, 1 to press and hold the ball seats 4, 4 toward the ball 3. Therefore, in the resulting ball valve, as shown in FIG. 5, only the outer circumferential surface of the ball seat 4 is held by the valve body, and the inner circumferential surface is not pressed against the ball. Therefore, when the ball 3 is opened or closed, the ball seat 4
was deformed as shown by the broken line in FIG. 5, and was repeatedly bent when the opening and closing operations were repeated, resulting in a disadvantage that the watertightness between the ball 3 and the ball 3 was impaired.

Since the above-mentioned drawbacks can be overcome by holding the end faces of the ball seat, the present invention attempts to provide a method for manufacturing such a compact ball valve.

Next, the present invention will be explained with reference to the drawings.

1 and 2 are cross-sectional views showing one embodiment of the method for manufacturing a ball valve of the present invention, in which 1 is a core mold and 2 is an outer mold.

A ball 3 is inserted into the core molds 1, 1, and the ball 3 is inserted into the core molds 1, 1.
Ball seats 4, 4 are fitted on both sides of the
Around this, outer molds 2, 2 having a cavity forming the outer shape of the valve body are arranged.

The outer molds 2 and 2 are fixed molds 5 of the injection molding device, respectively.
and a movable mold 6, and are made to collide and separate when the movable mold 6 operates.
51, and slides on the movable die 6 to collide and separate in response to the operation of the movable die 6.

In the present invention, the core molds 1 and 1 have a ball seat pressing projection 1 that presses the ball seat 4 against the ball 3.
1 is formed. The projections 11 may be formed so as to press the ball seat 4 toward the ball at multiple locations in the circumferential direction, as shown in FIG. Size of protrusion 11 and circumferential protrusion 1
The spacing between the ball seats 4 and the balls 3 is determined so that the ball seats 4 are pressed toward the balls 3 without any delay, but it is sufficient that the ball seats 4 are provided at four locations in the circumferential direction. This protrusion 1
1 is adjusted so as to press the ball seat 4 toward the ball 3 when the core molds 1, 1 are moved so as to abut each other by the taper pins 51, 51.

In order to manufacture a ball valve using the above-mentioned apparatus, when the movable mold 6 of the apparatus is open with respect to the fixed mold 5 and the core molds 1 and 1 are separated, the spindle is attached to the outer mold 2 on the movable mold 6 side. The balls 3 are set by fitting the ball seats 4 into the core molds 1 and 1. When the movable mold 6 is clamped to the fixed mold 5 by a mold clamping device (not shown) and the mold is closed,
The core molds 1, 1 are fitted into the ball 3, and the outer molds 2, 2 are closed together, and as shown in FIG. A space corresponding to the valve body is formed between 4 and the outer mold, and molten resin is press-filled into this space through the injection port 52 and cooled.
When the movable mold 6 is separated from the fixed mold 5, the valve moves away from the fixed mold 5 with respect to the movable mold 6, and then the core molds 1, 1
are separated from each other along the taper pins 51, 51, and the valve is removed from the outer mold 2.

In the present invention, the ball seat 4 is pressed against the balls 3 by ball seat pressing protrusions 11 formed at intervals in the circumferential direction of the core molds 1, 1, and between the core molds 1, 1 and the ball seats 4, 4. A gap is formed in between, and the molten resin is press-fitted into this gap to form a holding piece that presses the ball seat 4 toward the ball 3. Therefore, the resulting valve is attached to the spindle 3 as shown in FIGS. 3 and 4.
1 and ball seats 4, 4 are embedded in the valve body 7, and the side surfaces of the ball seats 4, 4 are pressed toward the ball 3.

Note that the ball seat 4 may be a hollow annular body.

As described above, the method for manufacturing a ball valve of the present invention is to press a plurality of circumferential locations of a ball seat toward the ball with a ball seat pressing protrusion formed in a core shape, and to separate the core portions other than the protrusions from the ball seat. A gap is formed between the molten resin and the molten resin.
During this period, the ball seat is pressed toward the ball 3 by a holding piece formed by the molten resin press-fitted into the valve, and the opening and closing operations of the ball are repeated. Since the ball seat is only subjected to compressive force and is not subjected to repeated bending stress, the watertightness between the ball seat and the balls is not impaired.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of essential parts showing one embodiment of the present invention,
Figure 2 is a sectional view taken along the - line in Figure 1;
The figure is a sectional view showing an example of a ball valve obtained by the present invention, FIG. 4 is a sectional view taken along the - line in FIG. It is. 1: Core type, 11: Ball seat presser projection, 2:
External mold, 3: Ball, 4: Ball seat, 5: Fixed type, 6: Movable type.

Claims (1)

[Claims] 1. A ball with a spindle and a ball seat are fitted into a core mold that forms a flow path, and an outer mold that has a cavity that forms the outer shape of the valve body is placed around it, and the space between the core mold and the outer mold is filled. In a method for manufacturing a ball valve that is filled with molten resin, a plurality of locations in the circumferential direction of a ball seat are pressed toward the ball with a ball seat pressing projection formed in a core shape, thereby separating the core mold portions other than the projections and the ball seat. A method of manufacturing a ball valve, characterized in that a gap is formed between the ball valve and the ball valve.