JP2009209973A - Valve unit and manufacturing method of valve unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a valve unit which can attain miniaturization and lightweight by securing a seal property of the valve unit. <P>SOLUTION: A clearance generation when closing valve is reduced in such a way that a seal section 22 of a valve element 2 is contacted to a valve port 16 of a valve seat 17, that a shaft member 20 is moved in the valve seat 17 direction, that pressurization and heat-treatment are performed while keeping a deformation of depress direction of the seal section 22, that a compression permanent strain profiled in the valve seat 17 and the valve port 16 is generated in the seal section 22, and that a contact surface profile between the valve seat 17 and the seal section 22 of the valve element 2 is processed in identification. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a valve device that controls fluid flow and a method for manufacturing the valve device.

  In a valve device through which fluid (gas or liquid) circulates, the fluid is shut off by bringing a valve body, which can be freely attached and detached, into contact with a valve seat serving as a fluid entrance and exit. At this time, if the sealing performance between the valve seat and the valve body is poor, the fluid is not completely cut off and the desired performance cannot be obtained. Here, if the flatness (indicator of how flat the surface is) or straightness (indicator of how straight) the valve seat and valve body are when both are zero, the valve seat and valve body When contacted, there is no gap and sealing performance is ensured. However, in practice, variations always occur due to processing. As a result, the flatness or straightness does not become zero, but a gap is generated when the valve seat and the valve body come into contact with each other. For this reason, the valve body or the valve seat is deformed by applying a load to the valve seat and pressing the valve body, thereby eliminating a gap between the valve body and the valve seat to ensure sealing performance. At this time, a rubber or a soft resin material that is more easily deformed than a metal material may be used for the valve body. However, rubber or soft resin material has a limit in processing accuracy at the time of molding, and as the valve device becomes larger, the processing accuracy becomes worse and it becomes difficult to ensure sealing performance. In addition, when the required sealing performance becomes stricter, it is necessary to increase the load for pressing the valve body against the valve seat in order to secure the sealing performance, so the drive part for pressing the valve body against the valve seat becomes larger and the weight increases. Become.

In order to ensure the sealing performance, for example, in Patent Document 1, the portion of the valve seat 2 that contacts the valve body 3 is formed in a flat shape so that the contact surface 33a of the valve body 2 is in close contact with the contact surface 2a of the valve seat 2. A shut-off valve is disclosed in which a corner 2c where the valve seat 2 and the inner surface 2b of the valve seat 2 intersect is formed in an arc shape.
JP-A-8-210545 (FIG. 1, [0015])

  In the technique described in Patent Document 1, the valve seat is formed in a flat shape so as to be in close contact with the contact surface of the valve body. However, the contact surface between the valve body and the valve seat is a variation during processing of the valve body and the valve seat. Therefore, it is difficult to completely eliminate the gap, so it is necessary to apply pressure to the valve body and press it against the valve seat to eliminate this gap. For this reason, there is a limit to reducing the size and weight of the valve device because it is necessary to secure a driving portion for applying pressure and to have a structure that can withstand the pressure.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a valve device capable of ensuring the sealing performance of the valve device and reducing the size and weight.

  The means taken to solve the above-mentioned problems is that a valve seat provided between the introduction hole and the lead-out hole, and a rubber or soft resin material as a base material are heated after molding to cause compression set. And a valve body that is integral with the seal portion and that blocks the flow of fluid flowing through the valve seat by separating the seal portion from the valve seat.

  Moreover, it is good to heat a seal part in the state contact | abutted with the valve seat.

  Furthermore, the distortion rate of the compression set generated as a result of heating is preferably 0.7% or more.

  In the present invention, since the seal portion that comes into contact with and separates from the valve seat made of rubber or a soft resin material is heated after being molded to cause compression set, the flatness or straightness of the seal portion is heated. Therefore, it becomes smaller than when no compression set is generated. For this reason, the gap between the seal portion and the valve seat is smaller than when the compression set is not generated without being heated, so that the sealing performance can be ensured even if the load pressing the seal portion against the valve seat is small. Can be reduced in size and weight.

  At this time, if the seal part is heated in contact with the valve seat, the seal part is deformed to a shape close to the shape of the valve seat, so the gap with the valve seat becomes smaller, so the seal part is pressed against the valve seat. The load can be further reduced.

  Further, when the distortion ratio of the compression set of the seal portion is 0.7% or more, it becomes easy to absorb the gap between the seal portion and the valve seat that is produced when the valve device is manufactured, and it becomes easy to ensure the sealing performance.

  Hereinafter, embodiments of the present invention will be described in detail.

  As shown in FIG. 1, the valve device 1 of the present embodiment includes a body 10 made of metal or resin, a membrane-like diaphragm 3 based on a polymer material such as rubber or soft resin material, and metal or resin. And a valve body 2 made of metal. The body 10 includes a first body 11 and a second body 12 (partially shown in FIG. 1) attached to the first body 11 with a fixture 11k such as a bolt. The first body 11 is formed between an introduction hole 14 into which a fluid (a gas such as air or a liquid such as water) is introduced, a lead-out hole 15 through which the fluid is led out, and the introduction hole 14 and the lead-out hole 15. And a valve seat 17 having a ring shape forming a valve port 16 having a circular shape. The introduction hole 14 is connected to an introduction source (not shown) for feeding fluid. The outlet hole 15 is connected to an outlet source (not shown) from which the fluid supplied from the inlet hole 14 is discharged.

  In addition, a diaphragm 3 based on a polymer material such as rubber or a soft resin material is provided in the body 10 to prevent fluid flowing through the first body 11 from flowing into the second body 12. The outer peripheral portion 30 of the diaphragm 3 is sealed by being sandwiched between the first flange portion 11c of the first body 11 and the second flange portion 12c of the second body 12, and the fluid flowing through the first body 11 is allowed to flow. Leakage to the outside through the outer periphery 30 of the The diaphragm 3 includes an outer peripheral part 30, a fixed film part 31 disposed on the upper surface side of the valve body 2, and a movable film part 32 having a cylindrical shape. In response to the opening / closing operation of the valve body 2 in the directions of the arrows M1 and M2, the diaphragm 3 operates and deforms after preventing the fluid flowing through the first body 11 from flowing into the second body 12.

  The valve body 2 is attached to the central region of the diaphragm 3 via the shaft member 20 so as to be positioned below the diaphragm 3. The valve body 2 includes a hard portion 21 having rigidity such as a metal fixed to the lower end portion of the shaft member 20, and a rubber or a soft resin material coated on the lower surface side of the hard portion 21 so as to cover the periphery of the hard portion 21. And a sealing portion 22 formed of the sealing material.

  In this embodiment, the valve body 2 is flat. However, the shapes of the valve body and the valve seat are not particularly limited as long as the valve body and the valve seat come into contact with each other, and may be replaced with various shapes. Can do. Further, as a method of opening and closing the valve body 2 in the directions of the arrows M1 and M2, a driving method used for opening and closing a normal valve device such as air or electricity can be applied.

  Next, the manufacturing method of the sealing part 22 of the valve body 2 of this embodiment is demonstrated.

  The shaft member 20 is driven in the valve closing direction (M1 direction in FIG. 1), a predetermined pressure is applied to the valve port 16 of the valve seat 17, and the seal portion 22 of the valve body 2 is pressed and brought into contact therewith. Next, a heat treatment is performed while maintaining a predetermined temperature in a heating furnace set at a predetermined temperature in this state. In this way, by performing the pressurizing / heating treatment for applying the heat treatment while applying pressure, a compression set is forcibly generated at the contact portion of the seal portion 22 with the valve seat 17. In this case, the pressure to be applied (pressure applied), the heating temperature, and the heating time are appropriately determined depending on the material and shape of the seal portion 22 and the specifications required for the seal. In the present embodiment, for example, a valve device having a diameter of 40 mm is used, and the seal portion 22 is made of EPDM rubber (ethylene / propylene rubber) having a thickness of 3 mm. Was held in the heating furnace for 10 to 20 hours and subjected to pressure and heat treatment.

  Table 1 shows the results of the evaluation of the sealing properties of the treated product subjected to pressure and heat treatment as described above and the untreated product. Here, the hardness of the EPDM rubber in the seal portion 22 changes (becomes harder than the untreated product) by the pressurization and heat treatment. Therefore, the hardness of the seal part of the treated product is A58 (test method JIS K6253) in which the hardness before treatment is the same as that of the untreated product and the hardness after treatment is hard (Example 1) and the hardness before treatment is soft and after treatment. The evaluation was performed using two types (Example 2) of EPDM rubber having the same hardness as A58 (test method JIS K6253) as that of the untreated product. Moreover, the sealing property was evaluated by the following method.

A force (pressing load) for pressing the seal portion 22 against the valve port 16 is brought into contact with the shaft member 20 without being applied thereto. Next, a pressing load is applied in the valve closing direction of the shaft member 20 to press the seal portion 22 against the valve port 16. The amount of displacement of the shaft member 20 when the pressing load is changed (same as the amount of deformation of the seal portion 22) is measured by a linear gauge, and air is supplied from the introduction hole 14 at a pressure of 40 to 60 KPa. The air leakage from the outlet hole 15 set to atmospheric pressure is confirmed. Table 1 shows the pressing load when air leakage from the lead-out hole 15 is eliminated, and the amount of deformation (crushing amount) of the seal portion 22 at that time.

  As is apparent from the results in Table 1, the treated product subjected to pressure and heat treatment has a smaller pressing load than the untreated product, and the amount of crushing of the seal portion 22 is small, so that air leakage can be suppressed and the sealing performance. Has improved. Further, when Example 1 and Example 2 of the processed product subjected to pressure and heat treatment are compared, Example 2 is more improved in sealing performance than Example 1. For this reason, when the hardness after pressure and heat treatment is adjusted, the sealing performance is improved as compared with the case where the hardness is not adjusted.

  Table 1 shows the flatness of the surface of the valve seat 17 of the seal portion 22 of the treated product (Example 1) and the untreated product (Comparative Example) subjected to pressurization and heat treatment. The results measured by (manufactured by Keyence Corporation) are shown.

  From the results in Table 1, the flatness of the untreated product is 40 μm, and the flatness of the treated product is 16 μm. From this, by performing the pressure and heat treatment, the EPDM rubber of the seal portion 22 is heated for a long time in a state in which a pressure is applied. It can be seen that the degree is improved from 40 μm to 16 μm. For this reason, the clearance gap produced between the valve port 16 and the seal part 22 becomes small, a clearance gap can be eliminated with a small pressing load, and the sealing performance is improved.

  Here, the pressing load applied to the shaft member 20 for suppressing air leakage and the crushing amount of the seal portion vary depending on the diameter of the valve device. If the diameter is smaller than φ40 mm of the present embodiment, the pressing load smaller than that of the present embodiment. Can suppress leakage. Further, if the material and hardness of the seal portion 22 are changed, the amount of deformation of the seal portion 22 that occurs when a load is applied to the seal portion 22 changes, so that the pressing load that gives the amount of deformation necessary to suppress leakage changes. For this reason, by appropriately setting the material and hardness (particularly, hardness after pressure and heat treatment), the pressing load necessary for the seal can be arbitrarily adjusted so as to meet the required specifications of the valve device.

  Further, in this embodiment, the seal portion 22 has a thickness of 3 mm, and the difference in the amount of crushing that causes no air leakage between the pressurized and heat-treated valve device (Example 1) and the untreated valve device (Comparative Example). Is 0.02 mm. The fact that the crushing amount of the pressurized and heated valve device is 0.02 mm smaller than that of the untreated valve device means that the smoothness of the surface of the seal portion 22 on which the valve port 16 of the valve seat 17 abuts is improved. It shows that. This means that the flatness is reduced by 0.02 mm. (The flatness measurement results in Table 1 are 40 μm−16 μm = 24 μm (0.024 mm).) When 0.02 mm is expressed in terms of distortion (%), it is approximately 0.7%. Therefore, if a compression set having a distortion rate of 0.7% or more is applied to the seal portion 22, the pressing load can be reduced.

  As described above, according to the embodiment of the present invention, the sealing portion 22 of the valve body 2 is heated while being in contact with the valve port 16 of the valve seat 17 and is subjected to pressurization / heating treatment. The contact portion of the seal portion 22 with the valve port 16 is forced to be permanently deformed and deformed. As a result, the contact portion of the seal portion 22 with the valve port 16 is deformed to a shape close to the shape of the valve port 16 of the valve seat 17, and between the valve port 16 and the contact portion of the seal portion 22 with the valve port 16. The gap that has occurred in the gap is smaller than when no pressure or heat treatment is performed. As a result, the seal can be sealed with a smaller pressing load than when no pressurization / heating treatment is performed, so that the driving portion for pressing the seal portion 22 against the valve port 16 can be reduced, and the pressing load is reduced. The structure of the minute valve device can be simplified and thinned. For this reason, the valve device can be reduced in size and weight.

  In addition, since the seal portion 22 has a compression set distortion rate of 0.7% or more, the gap between the seal portion 22 and the valve port 16 of the valve seat 17 generated when the valve device is manufactured can be absorbed and reduced. it can. As a result, the sealing portion 22 can be made with a small deformation to eliminate a gap and ensure sealing performance, so that the pressing load can be reduced.

  As mentioned above, although this invention was demonstrated according to the said embodiment, this invention is not limited only to the said aspect, Various aspects based on the principle of this invention are included.

It is a valve apparatus in an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Valve apparatus 10 Body 11 1st body 12 2nd body 14 Introducing hole 15 Deriving hole 16 Valve port 17 Valve seat 2 Valve body 22 Seal part

Claims (5)

  A valve seat provided between the introduction hole and the lead-out hole, a seal part in which compression set is generated by being heated after molding using a rubber or a soft resin material as a base material, and the seal part are integrated. A valve device comprising: a valve body that shuts off a flow of fluid flowing through the valve seat by bringing the seal portion into contact with the valve seat.   The valve device according to claim 1, wherein a distortion rate of the compression set of the seal portion is 0.7% or more. A valve seat provided between the introduction hole and the lead-out hole, a seal portion made of rubber or a soft resin material as a base material, and the seal portion are integrated with the seal portion so as to be separated from and in contact with the valve seat. A valve body that shuts off the flow of fluid flowing through the valve seat,
A method for manufacturing a valve device, comprising: forming a seal portion and heating the seal portion to cause compression set at a contact portion of the seal portion with the valve seat.   The method for manufacturing a valve device according to claim 3, wherein the seal portion is heated while being in contact with the valve seat.   The method for manufacturing a valve device according to claim 3 or 4, wherein the compression set having a strain rate of 0.7% or more is applied to the seal portion.

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