JPS6117773A - Diaphragm valve - Google Patents

Abstract

PURPOSE:To simplify a manufacturing process and the structure of a diaphragm valve by forming the diaphragm valve by the same material having required properties to form a valve portion and a diaphragm simultaneously. CONSTITUTION:A diaphragm 1 is required to have properties excellent in flexibility and resistance against buckling fatigue in view of its function, and a valve portion 2 is required to have a property excellent in wear-resistance. The diaphragm 1 and the valve portion 2 are solidly formed by hydrogenerated nitrile rubber, that is, vulcanized material of partial unsaturated nitrile hydride-conjugate diene copolymer rubber in which at least 50% of the conjugate diene unit part is hydrogenerated, which has both properties. This material is good in thermal resistance and exhaust gas-resisting property, and can be used with sufficient durability in a valve device using exhaust gas.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a diaphragm valve used, for example, as a pressure regulating valve in an exhaust gas recirculation device in an internal combustion engine.

<Conventional technology> In order to reduce NOx in exhaust gas and improve drivability, internal combustion engines for automobiles use exhaust gas regeneration, which adjusts combustion conditions by returning part of the exhaust gas to the combustion chamber according to intake pipe pressure, etc. A circulation device is used. Conventionally, the pressure regulating valve used in such exhaust gas recirculation equipment was
Publication No. 6 proposes a diaphragm valve in which a valve portion is attached to the center of the diaphragm. As shown in Fig. 4, this diaphragm valve has a diaphragm 31 made of fluorosilicone rubber or the like with excellent bending fatigue resistance and exhaust gas resistance.
The diaphragm 31 and the valve part 32 are separately made of different materials so that the valve part 32 made of rubber with excellent wear resistance is sandwiched and fixed together with the diaphragm 31 between an upper plate 33 and a lower plate 34. Therefore, since the diaphragm valve is manufactured by assembling many separately molded parts, the manufacturing process is complicated, and the structure of the diaphragm valve is also complicated.

On the other hand, as another prior art diaphragm valve, a valve part made of hard fluororubber is bonded or coated to the center of a diaphragm is proposed in Japanese Utility Model Application Publication No. 52-50159.

In a diaphragm valve with this structure, it is possible to mold the diaphragm using an insert instead of the upper plate and lower plate, but there is a problem with the adhesion between the diaphragm and the valve portion, so it has not yet been used as a fabric.

<Object of the Invention> The present invention has been made in view of the above points, and by constructing the diaphragm valve with the same material that has the required performance for both the diaphragm and the valve part, the valve part and the diaphragm can be used at the same time. The purpose of the present invention is to provide a diaphragm valve which can be molded and whose manufacturing process and structure can be simplified.

<Configuration of the Invention> To this end, the present invention provides a diaphragm valve in which a diaphragm is provided with a valve portion, in which a partially hydrogenated unsaturated nitrile in which at least 50% of the conjugated diene unit portion is hydrogenated is used.
The diaphragm and valve portion are made of the same material, which is a vulcanized product of conjugated diene copolymer rubber.

<Example> Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows a cross-sectional view of a diaphragm valve used as a pressure regulating valve in an exhaust gas recirculation system for an internal combustion engine.
The outer edge is sandwiched between the housing walls so as to be separated into a lower chamber 4b and a lower chamber 4b. A first port 5 and a third boat 8 are provided in the upper chamber 4a, and a valve seat 6 is formed at the inner protruding end of the first port 5. A valve portion 2 that opens and closes inside the diaphragm 1 is integrally provided in the center of the diaphragm 1. 7 is a second port provided in the lower chamber 4b of the housing 4; 9 is a coil spring that biases the valve portion 2 in the opening direction; this coil spring 9 is connected to the upper wall of the upper chamber 4a and within the diaphragm It is installed between the cup-shaped spring seat 3 buried therein.

Due to its functionality, the diaphragm 1 needs to have excellent flexibility and bending fatigue resistance, and the valve part 2 needs to have excellent wear resistance. , a hydrogenated nitrile rubber having both of these characteristics, that is, a vulcanizate of a partially hydrogenated unsaturated nitrile-conjugated diethyl copolymer rubber in which at least 50% of the conjugated diene units are hydrogenated (hereinafter referred to as hydrogenated NBR) It is integrally molded. Further, when the diaphragm 1 and the valve portion 2 are integrally molded, the spring seat 3 is attached by embedding its base in the diaphragm 1, that is, by insert molding. Therefore, before.

Unlike conventional diaphragm valves, there is no need to mold the diaphragm, valve part, upper plate, and lower plate separately and assemble them at predetermined positions, which simplifies the manufacturing process and structure. As shown in FIG. 2, there is no need to provide a through hole in the diaphragm 31 for the pin 35 for assembling the upper plate 33 and the lower plate 34, and there is no need for a means to ensure the sealing performance of the through hole.

Note that the term "hydrogenated NBR" as used herein refers to a product containing chemicals such as a vulcanizing agent, a filler, and an anti-aging agent, which are usually blended into rubber.

When the diaphragm valve configured in this way is used as a pressure regulating valve of an exhaust gas recirculation device, the first port 5 of the diaphragm valve is
is connected to a negative pressure passage that passes negative pressure to a pressure chamber of a control valve connected to an intake pipe of the internal combustion engine, and the second port 7 is connected to a constant pressure chamber of the control valve that controls the amount of exhaust gas recirculation, Third
Port 8 is opened to the atmosphere. Exhaust gas enters the lower chamber 4b through the constant pressure chamber, and the diaphragm valve, that is, the valve section 2, opens and closes according to the pressure of the exhaust gas to adjust the pressure in the negative pressure passage with atmospheric pressure, and the regulated control pressure is sent to the pressure chamber of the control valve to operate the control valve provided in the exhaust gas circulation passage, and the amount of exhaust gas recirculation is controlled according to the operating state of the internal combustion engine. At this time, the diaphragm 1 comes into contact with high-temperature exhaust gas, but the diaphragm made of the above-mentioned hydrogenated NBR has good heat resistance and exhaust gas resistance, and has sufficient durability to be used in valve equipment that uses exhaust gas. can do.

Table 1 shows the hydrogenated NBR forming the diaphragm l and valve part 2, the fluorosilicone rubber conventionally used,
Normal physical properties, heat resistance, exhaust gas resistance of fluororubber,
The results of a comparative test regarding wear resistance are shown below.

The normal physical properties in the above comparative test are JIS-6301
The heat resistance was measured based on JIS-8301 on each test piece that had been heat aged at 150'C! for 70 hours.The exhaust gas resistance was measured based on JIS-8301.
Immersed in exhaust gas condensed water for 480 hours to JIS-8
301, wear resistance is 85903-A9.
Load 61bg, angle 15°, drum rotation speed 33 rpm
,, sample rotation speed 25 Orpm, wear amount (c
c) was measured.

From the test results shown in Table 1 above, hydrogenated NBR has normal physical properties equivalent to or better than fluorosilicone rubber used in conventional diaphragms.

It can be seen that it has both heat resistance and exhaust gas resistance, as well as abrasion resistance that is equivalent to or better than the fluororubber used in conventional valve parts.

Furthermore, Table 2 shows the hydrogenated NBR of the shape shown in Figure 2.
The results of an operational durability test of a diaphragm valve using a diaphragm valve shown in FIG. 4 and a conventional diaphragm valve shown in FIG.

Table 2-11 From the test results shown in Table 2, the diaphragm valve of the present invention integrally molded with hydrogenated NBR has a higher
It can be seen that it has excellent durability. From this, it can be understood that the bending fatigue resistance of hydrogenated NBR is superior to that of fluorosilicone rubber.

Other Embodiments If the present invention is applied to a valve device in which the diaphragm and valve parts are separated due to the structure of the valve device, a long-necked valve rod 23 may be embedded in the diaphragm 21 as shown in FIG. It is also possible to mold the valve portion 22 on the valve rod 23 separately from the diaphragm 21. In this case as well, the valve portion and the diaphragm can be molded at the same time as in the above embodiment, and the manufacturing process can be simplified. Also, in valve devices that operate at high pressures, it is common to embed a fabric within the diaphragm. For example, in a diaphragm valve having the configuration as shown in FIG.
By integrally molding the valve part, manufacturing processes such as molding, adhesion, and assembly of the valve part can be simplified compared to conventional techniques.

<Effects of the Invention> As explained above, in the present invention, in a diaphragm valve in which a diaphragm is provided with a valve portion, a partially hydrogenated unsaturated nitrile-conjugated diene copolymer rubber in which at least 50% of the conjugated diene unit portion is hydrogenated is used. The diaphragm and valve portion were formed from the same vulcanized material. Therefore, the temperature resistance required for the diaphragm and valve section is
A diaphragm valve can be simultaneously molded using a single material that has excellent properties such as bending fatigue resistance, heat resistance, and abrasion resistance, which simplifies the manufacturing process and its structure compared to conventional methods, making it easier to manufacture. be able to.

[Brief explanation of the drawing]

1 to 3 and 5 show embodiments of the present invention,
Fig. 1 is a sectional view of a diaphragm valve in a pressure regulating valve, Fig. 2 is a sectional view of a diaphragm valve, Figs. 3 and 5 are sectional views of other implementations of the diaphragm valve, and Fig. 4 is a conventional diaphragm valve. FIG. 3 is a cross-sectional view of the valve. 1...Diaphragm, 2...Valve part. Patent application Toyoda Gosei Co., Ltd.

Claims (1)

[Claims] In a diaphragm valve in which a diaphragm is provided with a valve portion, the diaphragm and the valve portion are formed from the same material of a vulcanizate of partially hydrogenated unsaturated nitrile-conjugated diene copolymer rubber in which at least 50% of the conjugated diene unit portion is hydrogenated. A diaphragm valve characterized by: