JPH08121619A - Flow control valve - Google Patents

Abstract

PURPOSE: To provide a diaphragm valve having the sharp rise characteristics from the beginning of the valve opening. CONSTITUTION: A diaphragm valve disk 110 to constitute a diaphragm valve 100 supports the pressure of a diaphragm reference pressure chamber 124 and the gravity of a weight 104 by one face, and supports the pressure of a diaphragm fluid pressure chamber 122 by the other face. The weight 104 is set to the value corresponding to the valve opening pressure. When the force in the valve opening direction to be added by the pressure of the diaphragm fluid pressure chamber 122 exceeds the sum of the valve opening pressure Pr and the gravity by the weight 104, a seating part 112 opens a valve flow passage 138. The fuel vapor flows through a tank side flow passage 32T, a diaphragm valve chamber 120, the valve flow passage 138 and a canister side flow passage 32C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow control valve used, for example, to introduce vaporized fuel from a fuel tank into a canister.

[0002]

2. Description of the Related Art Conventionally, a flow control valve of this type has been disclosed in Japanese Patent Laid-Open No.
As described in Japanese Patent Publication No. 0-184779, it is used for a diaphragm valve built in a bidirectional valve for protecting a fuel tank accompanying the rise and fall of the vapor pressure of the fuel tank. 4 will be described. In FIG. 4, the bidirectional valve 200 has a partition wall 206 that divides the case body 202 into a first chamber 203 and a second chamber 204, and accommodates the check valve 210 in the first chamber 203. It has a structure in which it is sealed with a lid 212, the diaphragm valve 220 is housed in the second chamber 204, and the lid 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 22 of the diaphragm valve 220.
4 is opened by being separated from the seating surface 228 against the spring 226 to allow the fuel vapor to escape from the fuel tank to the canister, while the pressure in the fuel tank is reduced and the tank side connection port TP and the canister connection port CP When the pressure difference between and exceeds a predetermined value, the valve body 214 of the check valve 210 opens by separating from the seating surface 218 against the spring 216, and returns the fuel vapor from the canister to the fuel tank.

[0003]

Such a bidirectional valve 20
0, as shown in FIG. 5, the positive pressure P in the fuel tank
And the flow rate Q flowing through the diaphragm valve 220, when the fuel tank positive pressure P is below the valve opening pressure Pr, the valve is closed and the flow rate Q is 0, and above the valve opening pressure Pr, the valve is opened. It is desirable in terms of pressure regulating function to have a characteristic of a two-dot chain line in which the flow rate Q rises vertically. However, in the conventional diaphragm valve 220, normally, the gradual rise of the flow rate Q is shown near the valve opening pressure Pr as indicated by the alternate long and short dash line.

One of the factors showing these characteristics is that the opening of the valve body 224 depends on the spring 226. That is, the flow rate Q depends on the lift amount of the valve body 224, and this lift amount is obtained by the fluid pressure compressing the spring 226 via the valve body 224. However, the amount of compression of the spring 226 increases as the amount of compression increases according to Hooke's law. Therefore, if the fluid pressure reaches the valve opening pressure, the flow rate Q
Does not increase and does not reach a value sufficient to compress the spring 226, so that a sufficient flow rate Q cannot be obtained. Therefore, there is a problem that it is not possible to sufficiently obtain the characteristic that the fluid pressure rises sharply when it reaches the valve opening pressure Pr.

The present invention solves the above-mentioned problems of the prior art, and an object of the present invention is to provide a flow rate control valve in which the flow rate rapidly increases from a predetermined pressure at which the valve should be opened.

[0006]

The invention according to claim 1 made to solve the above-mentioned problems is achieved by a seat surface which is formed in a horizontal direction facing a flow path, and is seated on or separated from the seat surface. A valve body made of rubber or resin for opening and closing the flow path; and a weight attached to the valve body for applying gravity corresponding to the valve opening pressure of the valve body in the direction of the seat surface. Characterize.

According to a second aspect of the present invention, the valve element according to the first aspect is applied to a diaphragm valve element that receives a reference pressure on one surface and receives the fluid pressure of the flow passage on the other surface.

[0008]

The valve body of the present invention opens and closes the flow passage by seating on and away from the seat surface provided in the horizontal direction facing the flow passage. The valve body is made of rubber or resin and has a weight attached thereto. The weight is set to a weight that applies gravity corresponding to the valve opening pressure of the valve body. Even if the valve body opens, the weight has a constant force. Therefore, as in the case where the valve closing force is applied by the spring, a sharp rising characteristic can be obtained when the valve is opened, without decreasing the valve opening degree due to the increase of the valve opening force at the same time.

Further, in the present invention, as the valve element, a diaphragm valve element is suitably applied, and the diaphragm valve element receives the reference pressure and the gravity by the weight on one surface and the other surface on the other surface. It receives the fluid pressure passing through the flow path, and opens and closes by the balance of these.

[0010]

Preferred embodiments of the present invention will be described below in order to further clarify the structure and operation of the present invention described above.

FIG. 1 is a sectional view showing a bidirectional valve 10 connected between a fuel tank and a canister. In FIG. 1, the bidirectional valve 10 seals the case body 20 with a check valve lid body 60 and a diaphragm valve 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 is provided with a lower expansion portion 22 having a lower opening 24, and a check valve lid 6 is provided in a lower step portion 26 formed at a peripheral portion of the lower opening 24.
The lower opening 24 is sealed by the check valve lid body 60 by fitting the fitting stepped portion 62 of 0 and ultrasonic welding.

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

The case body 20 has a lower extension 22.
The side wall portion 28 is provided between the upper side portion 42 and the upper extension portion 42, and the side wall portion 28 is provided with a tank side pipe line portion 30T and a canister side pipe line portion 30C. 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, the canister-side flow passage 32 is provided in the canister-side conduit 30C.
C is formed, and the opening thereof is connected to the canister through a conduit not shown in the drawing.
Has become.

Further, in the case body 20, the flow path chamber 5 is provided.
Partition wall 4 that divides 0 into a check valve chamber 88 and a middle inner chamber 52
8 are formed. A through hole 49 is formed in the center of the partition wall portion 48, and the check valve chamber 88 and the inner inner chamber 52 are communicated with each other through the through hole 49.

Further, the diaphragm valve lid 70 for sealing the upper part of the case body 20 is provided with an outside air passage portion 74, and an outside air passage 76 is formed in the outside air passage portion 74, which will be described later. The diaphragm valve 100 is connected to one valve chamber.

Next, each structure and operation of the check valve 80 and the diaphragm valve 100 will be described. First, the check valve 80 is provided in the check valve chamber 88 below 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 check valve cover body 60 and the check spring guide member 82. Checking spring 84 for urging 90 toward the valve closing direction
It has and.

The check valve body 90 has a dish-shaped portion 94 having a bottomed hole 92, an extended peripheral edge portion 96 projecting from the outer periphery of the dish-shaped portion 94, and an annular protrusion formed at the tip of the extended peripheral edge portion 96. The check valve seat 47 is formed integrally with the portion 98 from rubber and is formed on the outer peripheral surface of the through hole 49 of the partition wall portion 48.
Sit or leave. With the configuration of the check valve 80, the check valve body 90 is configured so that the tank side flow passage 32 is closed in the valve closing direction.
The pressure from T and the urging force of the check spring 84 are applied, and the canister-side flow passage 32 through the through hole 49 in the valve opening direction.
The pressure of C is applied, and these balances open and close.

On the other hand, the diaphragm valve 100 is provided in the diaphragm valve chamber 120 formed by the upper portion of the flow passage chamber 50 of the case main body 20 and the diaphragm valve lid body 70, and the diaphragm valve body 110 and the Weight 104
It has and.

As shown in FIG. 2, the diaphragm valve body 110 has a flat plate-shaped seating portion 112, and a mounting projection portion 11 that is provided so as to project from the upper portion of the seating portion 112 and to which the weight 104 is mounted.
3 and a pressure receiving portion 114 provided on the outer periphery of the seating portion 112, and the peripheral portion of the pressure receiving portion 114 is the upper extension portion 42.
The diaphragm valve chamber 120 is divided into a diaphragm fluid pressure chamber 122 and a diaphragm reference pressure chamber 124 by being sandwiched between the upper step portion 46 and the lid body fitting portion 72 of the diaphragm valve lid body 70. It should be noted that the diaphragm fluid pressure chamber 122 is connected to the tank-side channel 32 through a channel (not shown).
Connected to T, the diaphragm reference pressure 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 sit on the valve seat member 130. The valve seat member 130 has a valve passage 1 at the center thereof.
It has an umbrella-shaped protruding portion 132 forming 38, and is welded to the mounting step portion 29 of the case body 20 by an ultrasonic welding method at the peripheral edge portion thereof.

The weight 104 has a mounting through hole 10 at the center thereof.
4a is formed from a doughnut-shaped metal material such as iron or stainless steel, and its weight W is
The pressure receiving area of the diaphragm valve body 110 is S and the atmospheric pressure is P
s and the valve opening pressure of the diaphragm reference pressure chamber 124 are Pr, the relationship of Wg = (Pr−Ps) · S is satisfied, and is set to, for example, about 20 g.

The weight 104 has a mounting through hole 104 for mounting the weight.
The mounting projection 113 of the diaphragm valve body 110 is fitted to a, and the upper surface of the weight 104 is engaged with the retaining projection 113a projecting from the side surface of the mounting projection 113, so that the diaphragm 104 is prevented from being pulled out. It is integrated with the valve body 110.

With such a configuration of the diaphragm valve 100, the diaphragm valve body 110 receives the pressure P of the diaphragm fluid pressure chamber 122 communicating with the tank side flow passage 32T in the valve opening direction and the weight in the valve closing direction. Gravity W of 104
g and the valve opening pressure Pr which is communicated with the outside air passage 76 are added, and the valve opening and closing is opened and closed according to their balance.

The check valve body 90 and the diaphragm valve body 110 are injection-molded from nitrile rubber (NBR) or fluororubber (FKM), while the case body 2
0, the check valve lid body 60, the diaphragm valve lid body 70, the valve seat member 130, and the like are injection-molded with 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 fluid pressure chamber 122 rises.
Open the valve to the equilibrium position by pushing down against the gravity and atmospheric pressure of. As a result, the fuel vapor whose pressure has risen in the fuel tank flows into the tank-side flow passage 32T → the connection flow passage (not shown) → the diaphragm fluid pressure chamber 122 → the valve flow passage 138 → the middle inner chamber 52 →
It flows to the canister side through the canister side flow path 32C.

On the other hand, when the pressure in the fuel tank decreases and becomes greater than the pressure of the canister by a predetermined differential pressure or more, the check valve body 9 is passed from the middle inner chamber 52 through the through hole 49.
The pressure applied to 0 exceeds the force of the urging force of the check spring 84 and the pressure of the check valve chamber 88, and the check valve body 90 pushes down the check spring 84 to open it to the equilibrium position. As a result, the fuel vapor in the canister is
It flows to the fuel tank side through the canister side flow passage 32C → the middle 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 10
0 opens to allow the fuel vapor in the fuel tank to flow to the canister. On the other hand, when the pressure in the fuel tank drops below a predetermined level, the check valve 80 opens 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-described valve opening operation of the diaphragm valve 100, the diaphragm valve body 110 receives the reference pressure Ps · S of the diaphragm reference pressure chamber 124 and the gravity Wg of the weight 104 on one surface thereof, and the diaphragm fluid pressure chamber 122. Pressure P ・ S on the other side, Ps ・ S + Wg <P ・ S
When the conditions of the above are satisfied, the seating portion 112 causes the valve passage 138
However, Ps · S + Wg applied to one surface is constant regardless of the opening of the diaphragm valve body 110.

Therefore, once the diaphragm valve body 11
If 0 is opened, as described in the related art, the valve opening degree is not restricted by the spring force, and the sharp opening characteristic shown in FIG. 5 in which the flow rate sharply increases at the valve opening pressure Pr is obtained. You can

Further, according to the diaphragm valve 100, not only the spring for applying the urging force to the diaphragm valve body 110, but also the member for supporting the diaphragm valve body interposed between the diaphragm valve body 110 and the spring is unnecessary. Therefore, the number of parts can be reduced, and the cost can be reduced.

The present invention is not limited to the above-described embodiments, but can be carried out in various modes without departing from the scope of the invention, and the following modifications can be made.

(1) In the above embodiment, as a means for mounting the weight on the diaphragm valve body, the mounting projection 11 of the diaphragm valve body 110 is attached to the mounting through hole 104a of the weight 104.
3 was fitted and further locked with the retaining projection 113a,
The present invention is not limited to this, and they may be integrated by an adhesive or in-mold molding, and the means therefor is not particularly limited.

(2) In the above embodiment, the weight used in place of the spring is applied to the diaphragm valve, but the present invention is not limited to this, and any valve that applies a force to the valve body in the valve closing direction may be used.
The present invention can be applied to various valves, for example, a check valve.

(3) As means for applying a force in the valve closing direction to the valve body, a weight may be used alone or a spring may be used in combination. For example, like a diaphragm valve installed in a vehicle,
When applied to a valve that tilts depending on the running condition, the spring can be used to hold the valve open against tilting.

(4) The shape of the weight is preferably seated evenly on the valve body in the valve closing direction. For example, as shown in FIG. 3, the weight 104A is formed in a trapezoidal cross section, and the diaphragm valve The shape may be such that a force is intensively applied to the seating portion 112 of the body 110.

(5) In the above embodiment, the diaphragm valve was operated at atmospheric pressure, but the invention is not limited to this, and it may be operated at another reference pressure, for example, in the intake manifold of an engine. It may be operated by pressure.

[0038]

As described above, according to the flow rate control valve of the present invention, the valve body that is seated and separated from the seat surface horizontally provided facing the flow path is made of rubber or resin, and By mounting a weight on the valve element that applies gravity in the valve closing direction, the force of the weight is constant regardless of the valve opening of the valve element, so that the valve closing force is applied by a spring. In addition, the valve opening does not decrease as the valve closing force increases simultaneously with the valve opening. Therefore, when the valve is opened, it is possible to obtain a flow rate characteristic that rises sharply and sharply.

Further, according to the second aspect, it can be suitably applied to the diaphragm valve body which receives the reference pressure and the gravity by the weight on one surface and the fluid pressure which passes through the flow path on the other surface.

[Brief description of drawings]

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

FIG. 2 is a cross-sectional view illustrating an enlarged main part of the diaphragm valve of the present embodiment.

FIG. 3 is an enlarged cross-sectional view illustrating an essential part of a diaphragm 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]

 CP ... Canister connection port 10 ... Bidirectional valve 20 ... Case body 22 ... Lower extension 24 ... Lower opening 26 ... Lower step 28 ... Sidewall 29 ... Mounting step 30C ... Canister side conduit 30T ... Tank side conduit Portion 32C ... Canister side flow passage 32T ... Tank side flow passage 34C ... Canister side port 34T ... Tank side port 42 ... Upper expansion portion 44 ... Upper opening 46 ... Upper step portion 47 ... Check valve seat 48 ... Partition portion 49 ... Through hole 50 ... Flow path chamber 52 ... Middle inner chamber 60 ... Check valve lid 62 ... Fitting step 70 ... Diaphragm valve lid 72 ... Lid fitting 74 ... Outside air duct 76 ... Outside air passage 80 ... Check valve 82 ... Check spring guide member 84 ... Check spring 88 ... Check valve chamber 90 ... Check valve body 92 ... Bottom hole 94 ... Dish-shaped portion 96 ... Extended peripheral portion 98 ... Annular protrusion 100 ... Die YAFFRAM valve 104 ... weight 104A ... weight 104a ... mounting through hole 110 ... diaphragm valve body 112 ... seating part 113 ... mounting projection 113a ... preventing projection 114 ... pressure receiving part 120 ... diaphragm valve chamber 122 ... diaphragm fluid pressure chamber 124 ... Diaphragm reference pressure chamber 130 ... Valve seat member 132 ... Umbrella-shaped protrusion 138 ... Valve flow path

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Joji Kasugai 1 Ochiai, Nagachiga, Kasuga-cho, Nishikasugai-gun, Aichi Toyoda Gosei Co., Ltd. Address within Toyoda Gosei Co., Ltd.

Claims (2)

[Claims] 1. A seat surface horizontally formed facing a flow path, a valve body made of rubber or resin for opening and closing the flow path by seating on or away from the seat surface, and a valve body mounted on the valve body. And a weight for applying gravity corresponding to the valve opening pressure of the valve body in the direction of the seat surface, and a flow control valve. 2. The valve body receives a reference pressure on one surface,
The flow control valve according to claim 1, wherein the other surface is a diaphragm valve body that receives the fluid pressure of the flow path.