JPH04101701A - Machining of valve plug having spherical seat deposit part - Google Patents

Abstract

PURPOSE:To machine precisely the spherical seat deposit part of a valve plug by cutting the seat deposit part of a valve plug through a process of advancing a cutting blade secured eccentrically to a rotary shaft which intersects the central line of the valve plug while the valve plug is rotationally fed around its central line. CONSTITUTION:While a valve plug 21 is rotationally fed around the central line 30 of a valve stem a cutting tool 10 is advanced while being secured eccentrically to a rotary shaft 31 provided to intersect the central line 30, and being in rotation together with the rotary shaft 31, so that the spherical seat deposit part 25 of the valve plug 21 is machined. That is, the valve plug 21 is rotationally fed around the central line 30, and the cutting blade 10 is secured eccentrically to the rotary shaft 31 which intersects the central line 30 of the valve plug 21, and rotates together with the rotary shaft 31, so that the spherical seat deposit part 25 of the valve plug is cut. When the feed quantity of the rotary shaft 31 is changed, the distance from the spherical seat deposit part 25 to the cutting blade 10 changes and hence the radius of the spherical seat deposit part 25 changes.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method of manufacturing a valve plug having a spherical seat.

[Prior Art] Typical valves equipped with a valve plug having a spherical seat include a ball valve shown in FIG. 4, a rotary valve shown in FIG. 5, and the like.

That is, the ball valve 1 shown in FIG. 4(a) includes a spherical valve plug 4 having a through hole 5 in the flow path 3 of the valve body 2, and the valve plug 4 is aligned with the center line of the valve body 2. By rotating the valve shaft 6 perpendicular to the valve shaft 6, the flow path 3 is opened, and the flow rate is controlled according to the rotation angle. The outer peripheral surface of the spherical valve plug 4 is a spherical surface whose spherical center coincides with the center of the plug, and is brought into close contact with the seating surface 8 of the seat ring 7 installed on the downstream side of the flow path 3, thereby creating a spherical seating portion 4A. is formed.

In this case, the processing method for the spherical seating portion 4A is as shown in Fig. 4 (
As shown in b), the rotary shaft 9 on which the spherical valve plug 4 is fitted is rotated around its center line, and the cutting blade 10 is made to follow the model or moved back and forth in an arc shape by numerical control. I am trying to obtain a predetermined spherical surface.

The rotary valve 11 shown in FIG.
and a pair of upper and lower arms 12B and 12C integrally protruding from the back surface of the valve body 12A. It is rotatably supported by a stud 14 protruding inside the main body 2, and the flow path 3 is closed by bringing the spherical seating portion 13 of the valve body 12A into close contact with the seating surface 8 of the seat ring 7 when normally, that is, fully closed. m
When the valve body 12A is rotated by the valve shaft 6, the flow path 3 is opened, and the flow rate is controlled according to the rotation angle.

The method of processing the spherical seat 13 of the valve body 12A is to rotate the valve body 12A along its center line as shown in FIG. As in the case of , a predetermined spherical surface is obtained by reciprocating in an arc shape along the spherical seating portion 13 .

Note that 15 is a holder that holds the arm portions 12B and 12C of the valve plug 12.

[Problems to be Solved by the Invention] By the way, all valve plugs having such a spherical seat correspond to a seat ring having a circular hole or a communication hole similar to the circular hole, and are usually pressed into contact with the seat ring by a spring means. has been done. Therefore, in order to stop the fluid reliably without leaking, the spherical seating portion 4A (13) is required to have a perfect spherical surface.

However, in the conventional machining method described above, even if the cutting blade 10 can be accurately fed in an arc shape by numerical control, the cutting portion at the tip of the cutting blade 10 may move slightly depending on the feeding position. Are known. In addition, machining is performed by applying various correction values such as wear on the cutting edge, but this is time consuming and requires high accuracy from the machine tool, causing an increase in costs.

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and its purpose is to rotate the cutting blade around an axis of rotation instead of reciprocating in an arc shape, thereby eliminating the troublesome An object of the present invention is to provide a method of machining a valve plug having a spherical seating part, which allows the spherical seating part to be machined with high precision without requiring extensive numerical control.

[Means for Solving the Problems] In order to achieve the above object, the present invention rotates and feeds a valve plug along its center line, and rotates the valve plug along a rotating shaft provided to substantially intersect with the center line. The seating portion of the valve plug is cut into a spherical surface by advancing a cutting blade that is eccentrically attached and rotates together with the rotating shaft.

[Operation] In the present invention, the valve plug is rotatably fed to its centerline layer. The cutting blade is eccentrically attached to a rotating shaft that substantially intersects with the center of rotation of the valve plug, and rotates with the rotating shaft to cut the spherical seat of the valve plug.When the feed rate of the zero-rotary shaft is changed, the cutting blade cuts the spherical seat. Since the distance from to the cutting edge changes, the radius of the spherical seating part changes.

[Embodiment N] Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

Fig. 1 is a perspective view showing the processing method according to the present invention, Fig. 2 is a diagram showing cutting marks on the processed surface, and Fig. 3 is a cross section of a main part of a valve device equipped with a valve plug processed and formed by the processing method. It is a diagram. In FIG. 3, the valve device 20 includes a valve plug 21 attached to the inner end of the valve shaft 6 and disposed within the valve body 2. As shown in FIG. As shown in FIG. 1, the valve plug 21 includes a valve body 22 made of a substantially hemispherical shell structure with a hollowed out interior, and cylindrical bearings integrally provided on the upper and lower surfaces of the valve body 22. The valve body 22 is composed of parts 23 and 24.
A band-shaped spherical seat 25 that is elongated in the rotational direction of the valve shaft 6 is formed on the outer peripheral surface of the valve shaft 6 so as to protrude one step higher, and an opening 26 forming an equal percentage characteristic section is formed at one end of the spherical seat 25. The width of the 0-spherical seating portion 25, which is formed to overlap with the 0-spherical seating portion 25, is set to be slightly larger than the inner diameter A of the seating surface 8 of the seat ring 7. Upper bearing part 23
The inner end of the valve shaft 6 is fitted into and integrally joined by welding or the like, and the lower bearing portion 24 is rotatably supported by a stud 14 protruding from the inner surface of the valve body 2. .

The outer end of the valve shaft 6 is connected to the upper surface opening 2 of the valve body 2.
It passes through the center hole 29 of the lid 28 that closes the lid 7 through the gasket 30 and projects to the outside.

Now, when processing the spherical seating portion 25 of the valve plug 21 having such a configuration, a plug material manufactured by casting or the like is first prepared. At this point, the bearing part 2
The inner and outer diameters and lengths of 3.24 are machined to predetermined dimensions, the opening 26 is formed in a predetermined shape, and the valve shaft 6 is attached to the bearing portion 23. Then, the plug material made of this semi-finished product is attached to a machine tool together with the valve stem 6, and rotated at a constant speed about the center line 30 of the valve stem 6. This rotational speed is approximately 2r, p, m.

The cutting blade 10 for cutting the spherical seating part 25 is provided at the tip of the arm part 32 of the rotating shaft 31, so that the cutting blade 10 cuts the spherical seating part 25.
The zero rotation axis 31, which is eccentric with respect to 1, is located at its center line 3
3 is arranged to intersect substantially perpendicularly to the center line 30 of the valve shaft 6, and is rotated by 500 to 800 r, p, m.

In this case, the radius of rotation of the cutting blade 10, that is, the rotation axis 31
The distance r to the center (for example, 18 m1), the width of the spherical seating portion 25, and the inner diameter A of the seat ring 7 (Fig. 3) are set so as to satisfy the relationship A < D < 2 r.

Then, when the valve plug 21 is rotated at low speed around the center line of the valve shaft 6 and advanced by a predetermined amount while rotating the rotary shaft 31 around its center 1!33, the cutting blade 10 is seated on the spherical surface of the valve plug 21. The portion 25 is cut to obtain a predetermined spherical surface.

The size of the spherical surface is determined by the amount of forward movement of the cutting blade 10, and when the amount of movement is small, the distance from the center of rotation of the valve plug 21 to the cutting blade 10 is large, so it becomes a spherical surface with a large radius; , since the cutting blade 10 approaches the valve plug 21, it becomes a spherical surface with a small radius.

FIG. 2 is a diagram showing cutting marks produced on the surface of the spherical seating portion 25. As shown in FIG. If the rotation center 30 of the valve plug 21 and the center 33 of the rotation shaft 31 intersect with each other, the cutting marks 34 will not be scratched or cut because the spherical seating portion 25 will be evenly cut in all processes of the cutting blade 10. The result is a beautiful mesh pattern (cross hatch) with no overlapping parts.Therefore, just by visually inspecting this pattern, you can determine whether or not an accurate spherical surface has been obtained, and there is no need to conduct a special sphericity test. There is no
Further, since the rotation center 30 of the valve plug 21 and the rotation center 33 of the rotation shaft 31 are spherically cut, they do not necessarily need to be perpendicular to each other, and may be inclined in the left-right or front-rear direction, but they are not substantially mutually It is necessary for the spherical seating portion 25 to intersect with the spherical surface to obtain a true spherical seating portion 25.

Moreover, unlike the conventional circular reciprocating movement, the cutting portion of the cutting edge of the cutting blade 10 according to the present invention simply rotates, so it always cuts exactly in the same area and does not change even with feeding. ．． Therefore, there is no need to perform special correction control to obtain a true spherical surface.

Note that the present invention can be applied not only to cutting but also to polishing. Polishing members such as grindstones or puffs are shaped too severely or are difficult to maintain.On the other hand, the method of the present invention, in which the same part always comes into contact with the processed surface of the workpiece, employs this method. It makes it extremely easy.

[Effects of the Invention] As described above, the method for processing a valve plug having a spherical seating portion according to the present invention includes rotating and feeding the valve plug around its center line, and setting the valve plug so that it substantially intersects with the center line. Since the cutting blade, which is eccentrically attached to the rotary shaft and rotates together with the rotary shaft, is advanced to cut the seating portion of the valve plug, a highly accurate spherical seating portion can be produced without special correction control. Obtainable.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the processing method according to the present invention, Fig. 2 is a diagram showing cutting marks on the processed surface, and Fig. 3 is a cross section of a main part of a valve device equipped with a valve plug processed and formed by the processing method. Figures 4(a) and 4(b) are cross-sectional views showing a conventional example of a ball valve and views showing processing of a valve plug, and Figures 5(a) and 5(b) are sectional views showing a conventional example of a rotary valve. FIG. 3 is a cross-sectional view and a diagram showing processing of the valve plug. 6 ・ 21 ・ 23. 26 ・ 31 ... Valve shaft, 10 ... Valve plug, 24 ... Bearing section, ... Opening, 30 ... - Rotating shaft, 33 ... Cutting blade, 22 ... Valve body, 25・-・Spherical seating part, ・Center line of the valve stem, ・・Center line of the rotating shaft. Patent applicant Yamatake Honeywell Co., Ltd.

Claims (1)

[Claims] While rotating the valve plug around its center line, the valve plug is seated by advancing a cutting blade that is eccentrically attached to a rotating shaft provided to substantially intersect with the center line and rotates together with the rotating shaft. A method of processing a valve plug having a spherical seating portion, characterized in that the portion is cut into a spherical surface.