JPH0640539U - Bidirectional valve - Google Patents

Abstract

(57) [Abstract] [Purpose] Diaphragm valve 1 that constitutes this bidirectional valve 10.
00 has a sharp rising characteristic from a predetermined valve opening pressure. [Constitution] In the bidirectional valve 10, the canister side flow passage 32C
When the pressure difference between the tank side flow path 32T and the tank side flow path 32T exceeds a predetermined value, fuel vapor is released from the canister to the fuel tank through the check valve 80. On the other hand, when the pressure on the tank side flow passage 32T side becomes higher than the atmospheric pressure by a predetermined pressure or more, the fuel is released from the fuel tank to the canister through the diaphragm valve 100. The diaphragm valve body 110 includes an elastic thin portion 11
2a is provided, and the elastic thin portion 112a is seated in a highly airtight state in which it elastically bends on the valve seat member 130 when the valve is closed to close the flow passage, and when the valve is slightly opened, the flow passage is opened. The fluid pressure deforms so as to expand the flow path, and the flow rate increases rapidly.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention mainly relates to a bidirectional valve used for introducing evaporated fuel from a fuel tank into a canister.

[0002]

[Prior art]

 Conventionally, this type of bidirectional valve has been used for protecting the fuel tank as the vapor pressure of the fuel tank rises and falls, as described in JP-A-60-184779. Will be described with reference to FIG. In FIG. 4, the bidirectional valve 200 has a partition wall 206 that divides the case main body 202 into an upper valve chamber 203 and a lower valve chamber 204, and the check valve 210 is housed in the upper valve chamber 203. In addition, the lower valve chamber 204 is sealed with the lid body 212, the diaphragm valve 220 is housed in the lower valve chamber 204, and the lid valve 222 is sealed. With this configuration, when the pressure in the fuel tank rises and the tank side connection port TP becomes higher than the atmospheric pressure by a predetermined pressure or more, the valve body 224 of the diaphragm valve 220 resists the spring 226 from the seating surface 228. When the fuel vapor is released from the fuel tank and escapes to the canister by being released, while the pressure inside the fuel tank drops and the pressure difference between the tank side connection port TP and the canister connection port CP exceeds a predetermined level. In addition, the valve body 214 of the check valve 210 is opened by moving away from the seating surface 218 against the spring 216 to return the fuel vapor from the canister to the fuel tank.

[0003]

[Problems to be solved by the device]

 In such a bidirectional valve 200, as shown in FIG. 5, in the relationship between the positive pressure P in the fuel tank and the flow rate Q flowing through the diaphragm valve 220, the fuel tank positive pressure P is closed at a predetermined pressure Pr or less. It is desirable in terms of pressure regulation that the flow rate Q is 0 and the valve has a characteristic of a solid line in which the flow rate Q rises vertically when the valve is opened at a predetermined pressure Pr or more. However, the conventional diaphragm valve 220 usually has a characteristic as shown by a broken line that shows a gradual rise of the flow rate Q near a predetermined pressure Pr, and it is required to approach an ideal characteristic as shown by a solid line. Was there.

By the way, the case body 202 is integrally molded by resin injection. Therefore, the seating surfaces 218 and 228 are also formed at the same time when the case body 202 is molded. However, the case body 202 is subject to resin shrinkage during injection molding, and it is difficult to form the seating surfaces 218 and 228 into sufficiently smooth surfaces. Particularly, in the diaphragm valve 220, the valve main body 224 itself is larger than the valve main body 224 of the check valve 210, and it is often arranged in the central portion of the case main body 202, and it is difficult to provide the seating surface 228 with high accuracy. . For this reason, the valve body 224 does not come into close contact with the seating surface 218, which is a hindrance to bringing the valve body 224 closer to the ideal diaphragm valve 220 in which the flow rate at the predetermined pressure Pr or less is zero.

The present invention solves the above-mentioned problems of the prior art, and provides a bidirectional valve equipped with a diaphragm valve having an excellent sealing property, which greatly reduces the flow rate up to a predetermined pressure at which the valve is opened. The purpose is to do.

[0006]

[Means for Solving the Problems]

 The present invention made to solve the above problems is provided in a case having a first connection port and a second connection port, and a first flow path connecting the first connection port and the second connection port. A diaphragm valve that opens when the pressure of the first connection port increases and a second flow path that connects the first connection port and the second connection port, and a predetermined difference between the first connection port and the second connection port. In a bidirectional valve having a check valve that opens at a pressure or higher, the diaphragm is disposed so as to face the first flow passage, and the seating portion is provided on the outer periphery of the first flow passage, and the seating portion. A valve body that closes the first flow path by sitting on the valve body; and a spring that is interposed between the case and the valve body and applies a biasing force to the valve body in the closing direction. Is a fluid that flows through the first flow passage when the valve is opened, and expands the flow passage when the valve is opened. It is characterized in that an elastic thin-walled portion is provided.

[0007]

[Action]

 In the bidirectional valve according to the present invention, when the pressure at the first connection port is increased, the increased pressure is applied to the diaphragm valve through the first flow path to open the diaphragm valve to open the first passage. Through the first connection port to the second connection port. On the other hand, when the pressure difference between the first connection port and the second connection port exceeds a predetermined value, the pressure difference passes through the second passage and is added to the check valve to open the check valve. Air is vented from the second connection port to the first connection port through the second passage.

Further, the diaphragm valve main body is provided with an elastic thin portion, and the elastic thin portion elastically bends to the seating portion provided on the outer periphery of the first flow path when the valve is closed. The first flow path is closed by sitting in a highly flexible state. Further, the elastic thin portion is deformed so as to expand the flow passage by the fluid flowing through the first flow passage in the initial stage of opening the valve. Therefore, once the valve is slightly opened, the first flow path is expanded and the flow rate is rapidly increased, resulting in a sharp rising characteristic when the valve is opened.

[0009]

【Example】

 A preferred embodiment of the present invention will be described below in order to further clarify the configuration and operation of the present invention described above.

FIG. 1 is a sectional view showing a bidirectional valve connected between a fuel tank and a canister. In FIG. 1, the bidirectional valve 10 seals the case body 20 with an upper lid body 60 and a lower lid body 70, and a check valve 80 and a check valve 80 are provided in a flow passage chamber 50 formed in the case body 20. It is configured by housing the diaphragm valve 100.

That is, the case body 20 includes the upper extension portion 22 having the upper opening 24, and the fitting step portion 62 of the upper lid body 60 is provided on the upper step portion 26 formed at the peripheral portion of the upper opening 24. It is fitted and sealed by ultrasonic welding.

On the other hand, the case main body 20 is provided with a lower expansion portion 42 having a lower opening 44, and a lid fitting portion 72 of a lower lid body 70 is attached to a lower step portion 46 formed on a peripheral portion of the lower opening 44. It is fitted and sealed by ultrasonic welding.

Further, the case main body 20 is provided with a side wall portion 28 between the upper expansion portion 22 and the lower expansion portion 42, and the side wall portion 28 has a tank side conduit portion 30T and a canister side conduit portion. The portion 30C is provided so as to project. A tank side flow passage 32T is formed in the tank side pipe passage portion 30T, and an opening thereof serves as a tank side port 34T connected to the fuel tank through a pipe passage (not shown). Further, a canister-side flow passage 32C is formed in the canister-side pipe passage portion 30C, and the opening thereof serves as a canister-side port 34C connected to the canister through a pipe passage not shown.

Further, in the case main body 20, a partition wall portion 48 that divides the flow passage chamber 50 into a check valve chamber 88 and a middle inner chamber 52 is formed. A through hole 49 is formed in the central portion of the partition wall portion 48, and the check valve chamber 88 and the middle inner chamber 52 are communicated with each other through the through hole 49.

The lower lid 70 that seals the lower part of the case main body 20 is provided with an outside air duct 74, and an outside air passage 76 is formed in the outside air duct 74, which will be described later. It is connected to one valve chamber of the diaphragm valve 100.

The check valve 80 is provided in an upper check valve chamber 88 of the case body 20. The check valve 80 is provided between the check valve body 90, the check spring guide member 82 that holds the check valve body 90, and the upper lid body 60 and the check spring guide member 82. And a check spring 84 for urging.

The check valve body 90 has a dish-shaped portion 94 having a bottomed hole 92, an expanded peripheral edge portion 96 protruding from the outer periphery of the dish-shaped portion 94, and an annular shape formed at the tip of the expanded peripheral edge portion 96. The protrusion 98 is integrally formed of rubber, and is seated on or separated from the check valve seat 47 formed on the outer peripheral surface of the through hole 49 of the partition 48. With the structure of the check valve 80, the check valve body 90 receives the pressure from the tank side flow passage 32T and the biasing force of the check spring 84 in the valve closing direction, and the canister through the through hole 49 in the valve opening direction. The pressure in the side flow passage 32C is applied, and these are balanced to open and close.

The diaphragm valve 100 is provided in a diaphragm valve chamber 120 formed by the lower portion of the flow path chamber 50 of the case body 20 and the lower lid 70. The diaphragm valve 100 includes a diaphragm valve body 110, a diaphragm spring guide member 102 that holds the diaphragm valve body 110, and a diaphragm spring 104. The diaphragm valve body 110 has a seat portion 112 and a pressure receiving portion 114 integrally formed of rubber. The seating portion 112 has an elastic thin portion 112a in the upper part, and is a gap 112b formed between the elastic thin portion 112a and the back surface of the elastic thin portion 112a with the diaphragm spring guide member 102. Further, in the diaphragm valve body 110, the peripheral portion of the pressure receiving portion 114 is sandwiched between the lower step portion 46 of the lower extension portion 42 and the lid fitting portion 72 of the lower lid body 70, so that the diaphragm valve chamber is closed. 120 is partitioned into an upper diaphragm valve chamber 122 and a lower diaphragm valve chamber 124, and is formed so as to be seated on the valve seat member 130. The diaphragm upper valve chamber 122 is connected to the tank side flow passage 32T via a flow passage (not shown), and the diaphragm lower valve chamber 124 is open to the atmosphere through the outside air passage 76.

The seat portion 112 of the diaphragm valve body 110 is formed so as to be seated on the valve seat member 130. The valve seat member 130 integrally includes a disc-shaped peripheral step portion 132, an umbrella-shaped protruding portion 134, and a connecting thin portion 136 connecting the peripheral step portion 132 and the umbrella-shaped protruding portion 134 with a thermoplastic resin. Has been formed. A valve passage 138 that connects the diaphragm upper valve chamber 122 and the middle inner chamber 52 is formed in the center of the peripheral step portion 132. The valve seat member 130 is welded to the mounting step 29 of the case body 20 at the peripheral step 132 by ultrasonic welding.

With such a configuration of the diaphragm valve 100, the diaphragm valve body 110 receives the pressure of the diaphragm upper valve chamber 122 through the tank side flow passage 32T in the valve opening direction and the urging force of the diaphragm spring 104 and the external air in the valve closing direction. Atmospheric pressure will be applied through the passage 76, and the balance will open and close it. Since the seating portion 112 of the diaphragm valve body 110 has an elastic thin portion 112a, when the diaphragm valve body 110 is closed, the elastic thin portion 112a of the seating portion 112 of the diaphragm valve body 110 has a valve seat member 130. The umbrella-shaped protrusion 134 partially pushes the gap 112b toward the void 112b to elastically deform it. Therefore, the seating portion 112 is seated on the valve seat member 130 in a pressed state by the elastic deformation of the elastic thin portion 112a.

The check valve body 90 and the diaphragm valve body 110 are injection-molded from nitrile rubber (NBR), fluororubber (FKM), or the like, while the case body 20, the upper lid body 60, the lower lid body 70, or the like. Each member such as the valve seat member 130 is injection-molded from a thermoplastic resin such as polyacetal or nylon.

Next, the opening / closing operation of the bidirectional valve 10 will be described. Now, when the pressure in the fuel tank becomes higher than the atmospheric pressure by a predetermined amount or more, the pressure in the diaphragm upper valve chamber 122 rises, and the diaphragm valve body 110 is pushed down against the diaphragm spring 104 and the atmospheric pressure to reach the equilibrium position. Open until. As a result, the fuel vapor whose pressure has risen in the fuel tank passes through the tank-side flow passage 32T, the connecting flow passage (not shown), the diaphragm upper valve chamber 122, the valve flow passage 138, the middle inner chamber 52, and the canister side flow passage 32C. It flows to the star side.

In such a valve opening operation of the diaphragm valve 100, when the diaphragm valve body 110 moves from the closed state of FIG. 2 (A) in the direction away from the umbrella-shaped protrusion 134 of the valve seat member 130, the diaphragm valve body 110 of FIG. As shown in B), the elastic thin portion 112a returns to a flat plate state from the state of being elastically pressed and deformed. Then, when the elastic thin portion 112a is slightly separated from the umbrella-shaped protruding portion 134 of the valve seat member 130 to form a gap, the fluid flows into the gap. As shown in FIG. 2C, the pressure of the fluid flowing through the gap causes the elastic thin portion 112a to elastically deform toward the recess side and expands the flow path to allow the fluid to flow. Therefore, when the elastic thin portion 112a is elastically deformed by the umbrella-shaped protrusions 134 and is slightly separated from the valve seat member 130, the flow path is expanded due to the deformation of the elastic thin portion 112a. Therefore, it is possible to obtain a sharp rising characteristic in which the flow rate sharply increases.

On the other hand, when the pressure in the fuel tank decreases and the pressure in the canister becomes higher than the fuel tank by a predetermined differential pressure or more, the pressure applied to the check valve body 90 from the inner chamber 52 through the through hole 49 is checked. When the urging force of the spring 84 and the pressure of the check valve chamber 88 are exceeded, the check valve body 90 pushes up the check spring 84 to open it to the equilibrium position. As a result, the fuel vapor in the canister flows to the fuel tank side through the canister side flow passage 32C → the inner inner chamber 52 → the through hole 49 → the check valve chamber 88 → the tank side flow passage 32T. At this time, since the valve opening pressure of the diaphragm valve body 110 is higher than the valve opening pressure of the check valve 80, the diaphragm valve 100 does not open.

Therefore, when the pressure in the fuel tank becomes higher than the atmospheric pressure by a predetermined amount or more, the diaphragm valve 100 opens to flow the fuel vapor in the fuel tank to the canister, while the pressure in the fuel tank decreases by a predetermined amount or more. Then, the check valve 80 is opened and the fuel vapor in the canister is returned to the fuel tank. Therefore, the pressure in the fuel tank is maintained within the predetermined range.

In the above embodiment, the valve seat member 130 seated on the diaphragm valve body 110 is a small part that is injection molded separately from the case body 20. Therefore, the valve seat member 130 is hardly deformed due to molding shrinkage, so that the valve seat member 130 having high surface accuracy can be obtained. By using the valve seat member 130, the diaphragm valve body 110 is seated on the valve seat member 130 in an airtight state, so that the flow rate at the time of closing the valve is reduced and the characteristics of the ideal diaphragm valve 100 are approached.

Further, since the umbrella-shaped protruding portion 134 of the valve seat member 130 is formed thin, high surface accuracy is obtained, and therefore, when the diaphragm valve body 110 is seated on the valve seat member 130, high accuracy is achieved. It is possible to improve the sealing property with respect to the diaphragm valve body 110 by seating with the line contact.

Further, in the above embodiment, the valve seat of the diaphragm valve 100 is provided on the valve seat member 130 which is a separate member from the case main body 20, so that only the check valve seat 47 of the check valve 80 is provided on the partition wall portion 48. The thickness of the partition wall 48 can be reduced. With this, sink marks due to resin contraction at the partition wall portion 48 can be suppressed, and thus the surface accuracy of the check valve seat 47 of the check valve 80 can be improved. Therefore, it is possible to obtain excellent characteristics of the check valve 80 that does not leak when the check valve 80 is closed.

Further, in the case main body 20, the check valve 80 and the diaphragm valve 100 are coaxially arranged, and the upper opening 24 of the upper expansion part 22 and the lower opening 44 of the lower expansion part 42 are also coaxially arranged. There is. If the upper lid 60 is fitted in the upper opening 24 and the lower lid 70 is fitted in the lower opening 44, stress is concentrated point-symmetrically at the joint between the two, so that ultrasonic welding can be performed at the same time. Therefore, it is possible to simplify the welding process only once.

FIG. 3 is an enlarged view showing the vicinity of the diaphragm valve body 110A and the valve seat member 130A according to another embodiment. In this embodiment, the seat 112A of the diaphragm valve body 110A is provided with an annular tongue 112c, the inner peripheral side of which is an annular space 112d, and the valve seat member 130A is provided with a diaphragm valve seat 134A which is a smooth surface. It is a composition. With this configuration, when the valve of FIG. 3 (A) is closed, the annular tongue 112c elastically deforms and comes into close contact with the diaphragm valve seat 134A, resulting in a high sealing property, and the valve of FIG. 3 (B) is opened. At the initial stage, the annular tongue 112c stands up and sits on the diaphragm valve seat 134A, and when the valve is slightly opened in FIG. 3 (C), the annular tongue 112c collapses toward the annular gap 112d side to expand its flow path. To do. Therefore, also in this embodiment, as in the embodiment of FIG. 1, the flow path is expanded by the deformation of the flexible annular tongue 112c after the initial valve opening, and a sharp rising characteristic can be obtained.

Although the diaphragm valve is operated at the atmospheric pressure in the above embodiment, the invention is not limited to this, and the diaphragm valve may be operated at another reference pressure, for example, in the intake manifold of the engine. It may be operated by pressure.

[0032]

[Effect of device]

 As described above, according to the bidirectional valve of the present invention, by providing the elastic thin portion on the valve body of the diaphragm valve, the elastic thin portion is seated on the outer periphery of the first flow path when the valve is closed. The first portion is seated on the portion in a highly airtight state, which is elastically bent, and the first passage is closed, and the passage is expanded by the fluid flowing through the first passage at the initial stage of valve opening. As it is deformed, its flow path is expanded and the flow rate is rapidly increased. Therefore, the diaphragm valve can obtain a sharp rising characteristic at a predetermined pressure.

[Brief description of drawings]

FIG. 1 is a sectional view showing a bidirectional valve according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram for explaining the operation of the diaphragm valve in the bidirectional valve.

FIG. 3 is an explanatory diagram for explaining the operation of the diaphragm valve in the bidirectional valve according to another embodiment.

FIG. 4 is a cross-sectional view showing a conventional bidirectional valve.

FIG. 5 is a graph showing a flow rate characteristic of a diaphragm valve.

[Explanation of symbols]

 10 ... Bidirectional valve 20 ... Case main body 32C ... Canister side flow passage 32T ... Tank side flow passage 50 ... Flow passage chamber 52 ... Medium inner chamber 80 ... Check valve 100 ... Diaphragm valve 102 ... Diaphragm spring guide member 104 ... Diaphragm spring 110 ... Diaphragm valve body 112 ... Seating part 112a ... Elastic thin part 112b ... Void 114 ... Pressure receiving part 120 ... Diaphragm valve chamber 122 ... Diaphragm upper valve chamber 124 ... Diaphragm lower valve chamber 130 ... Valve seat member 132 ... Peripheral step part 134 ... Umbrella-shaped protrusion 136 ... Thin portion connected

Claims (1)

[Scope of utility model registration request] 1. A case having a first connection port and a second connection port, and a first flow path that connects the first connection port and the second connection port are provided, and the pressure of the first connection port increases. A diaphragm valve that opens, and a check valve that is provided in the second flow path that connects the first connection port and the second connection port and that opens at a predetermined differential pressure or more between the first connection port and the second connection port, In the bidirectional valve having the above-mentioned diaphragm, the diaphragm is arranged so as to face the first flow passage, and the seating portion is provided on the outer periphery of the first flow passage, and the first flow passage is closed by sitting on the seating portion. A valve body, and a spring that is interposed between the case and the valve body and applies a biasing force to the valve body in a closing direction, wherein the valve body is seated on the seat portion. An elastic thin portion that is deformed so as to expand the flow passage by the fluid flowing through the first flow passage when the valve is opened is provided. Two-way valve for the butterflies.