JPH04331882A - Flow control solenoid valve - Google Patents

Abstract

PURPOSE:To provide a flow control solenoid valve by precisely flow rate in accordance with a current value even though a seat member having a bloating tendency is bloated. CONSTITUTION:A flow control solenoid valve 10 has a housing 11 provided therein with an inlet port 11, an outlet port 12, a communication port 14 and a valve seat part 15, and a valve element 17 is disposed in the housing 11. The valve element 17 is urged in the seating direction by means of a spring 46, leaf springs 33, 34 and bellows 20, and is further urged in the valve lifting direction by means of a spring 27. A solenoid 36 lifts the valve element 17 from the valve seat part 15 overcoming the urging force of the valve element 17 which is given a difference between the urging forces in both urging directions exerted by the urging members. Further, an annular rubber packing 19 having a bloated tendency is disposed in a part of the valve element 17 which is adapted to abut against the valve seat part 15, and further, a rubber plate 29 having a bloating tendency is provided to the spring 29 so as to compensate the valve opening characteristic in accordance with a bloating of the rubber part.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a solenoid valve for fluid control.

0002

2. Description of the Related Art A fluid control solenoid valve for controlling the intake air amount of an engine is disclosed in Japanese Patent Laid-Open No. 199076/1983. As shown in FIG. 7, this solenoid valve increases or decreases the flow rate of fluid flowing from an inlet 70 to an outlet 71 by increasing or decreasing the opening area between a valve body 72 and a valve seat 73 according to the current value to a coil 74. It is controlled continuously, and its current value I
The relationship between the flow rate Q and the flow rate Q is as shown in FIG. In such a fluid control solenoid valve, the valve body 72 is connected to the valve seat 7.
In order to ensure fluid sealing when seated on valve body 7,
2 or a rubber sheet material 75 is attached to the valve seat 73.

0003

However, when, for example, gasoline vapor or the like flows in, the rubber sheet material 75 swells and changes in size, causing the spring 76 that biases the valve body 72 to change.
77, the leaf springs 78, 79, and the bellows 80 change, the I-Q characteristic deviates as shown in FIG. 9, and there is a problem that the flow rate cannot be accurately controlled according to the current value.

An object of the present invention is to provide a fluid control solenoid valve that can accurately ensure a flow rate depending on the current value even if a swellable sheet member swells.

[0005]

[Means for Solving the Problems] The present invention provides a housing having a fluid passage and a valve seat portion formed in the middle of the fluid passage, and a valve seat disposed within the housing and seated and separated from the valve seat portion. a valve body supported movably in the seating direction, a first biasing member that biases the valve body in the seating direction, and a second biasing member that biases the valve body in the unseating direction; an electromagnetic solenoid for separating the valve body from the valve seat portion against a biasing force in the seating direction of the valve body due to a difference in biasing forces between the first and second biasing members; an annular swellable seal member disposed on the valve seat or the abutting portion of the valve body; and a seal member disposed on the second biasing member for correcting the valve opening characteristic due to swelling of the seal member. The gist of the present invention is a fluid control solenoid valve equipped with a characteristic correction member having swelling properties.

[0006]

[Operation] The valve body is seated by the biasing force in the seating direction due to the difference between the biasing forces of the first and second biasing members, and the part of the valve body that comes into contact with the valve seat is sealed with a sealing member. has been done. Then, the valve element is unseated from the valve seat portion by the electromagnetic solenoid against the urging force in the seating direction of the valve element due to the difference between the urging forces of the first and second urging members. At this time, when the sealing member swells, the characteristic correction member also swells and corrects the valve opening characteristics accompanying the swelling of the sealing member.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment embodying the present invention will be described below with reference to the drawings. FIG. 2 shows the overall configuration of a fuel evaporative gas diffusion prevention device for a vehicle. This vehicle is equipped with a gasoline engine, and an intake pipe 1 of the engine is provided with a throttle valve 2, and a surge tank 3 is provided downstream of the throttle valve 2. Also, fuel tank 4
A canister 6 is connected to the canister 6 through a communication pipe 5, and the canister 6 stores activated carbon 7 for adsorbing fuel evaporation gas from the fuel tank 4. Further, the canister 6 is provided with an atmosphere opening hole 8 for introducing fresh air. The canister 6 and the surge tank 3 are in communication via a purge pipe 9. A solenoid valve 1 for fluid control is located in the middle of this purge pipe 9.
0 is provided, and by opening the valve 10, fuel evaporative gas adsorbed on the activated carbon 7 of the canister 6 due to the negative pressure in the surge tank 3 is supplied to the intake system of the engine.

FIG. 1 shows a cross section of a fluid control solenoid valve 10. As shown in FIG. The aluminum housing 11 has an inlet 12 and an outlet 13, and further includes an inlet 12 and an outlet 13.
It has a communication port 14 that communicates with. A stepped portion is formed at the lower part of the communication port 14, and constitutes a valve seat portion 15 on which a valve body 17, which will be described later, is seated and unseated. Furthermore, the housing 11 has a solenoid chamber 16 below the outlet 13.

The valve body 17 seats on and leaves the valve seat 15 formed in the housing 11 to shut off and conduct the communication port 14. An annular groove 18 is formed on the upper end surface of the valve body 17,
The groove 18 has a substantially triangular cross section. Inside this annular groove 18 is a rubber packing 19 as a sealing member.
are fitted and fixed, and the rubber packing 19 is made of fluororubber (trade name: Viton). This rubber gasket 19
When the valve body 17 blocks the communication port 14, it is directly pressed against the valve seat portion 15 to seal the fluid.

A bellows 20 is integrally formed in the lower part of the valve body 17, and a lower end flange part 21 of the bellows 20 is arranged in contact with a step part 22 formed in the upper part of the solenoid chamber 16 of the housing 11 and below the step part 22. First side plate 23
They are airtightly held together. A shaft 24 passes through the center of the bellows 20, the solenoid chamber 16, the outlet 13, and the communication port 14 in the axial direction. shaft 2
The top end of the valve body 17 is fitted into the center hole 25 of the valve body 17, and a seat 26 formed near the top end is in contact with the bottom surface of the center hole 25 to support the valve body 17. A spring 27 serving as a second biasing member that biases the valve body 17 in the unseated direction is attached to the top end of the shaft 24 that protrudes from the upper surface of the valve body 17 . A rubber plate 29 serving as a characteristic correction member is disposed at the upper end of the spring 27 with a washer 28 interposed therebetween.

An enlarged view of this washer 28 and rubber plate 29 is shown in FIG. An annular rubber plate 29 is fixed to the upper surface of the washer 28 made of aluminum by baking. This rubber plate 29 is made of fluororubber (trade name: Viton), which is the same material as the rubber packing 19. The through hole 31 of the washer 28 is fitted into the protrusion 30 of the housing 11, and the rubber plate 29 is in contact with the housing 11. In FIG. 1, the bellows 20 is mounted so that the bellows part 32 is reduced in the axial direction when the valve body 17 is urged toward the seat 26 of the shaft 24 by the spring 27 and is locked to the shaft 24. It is being

The shaft 24 has its center portion and lower end portion held in the center portions of elastic leaf springs 33 and 34 located above and below the solenoid chamber 16, respectively, and reciprocates without sliding with respect to other portions in the axial direction. It is arranged so that it can be moved. The inside of the bellows 20 communicates with the communication port 14 through a communication hole 35 formed in the valve body 17. An electromagnetic solenoid 36 is arranged within the solenoid chamber 16. This electromagnetic solenoid 36 has a solenoid coil 37 (hereinafter referred to as
(simply referred to as a coil), a yoke 38 for forming a fixed magnetic path of the coil 37, a fixed core 39, a first side plate 23, a second side plate 40, and a movable plunger that can reciprocate in the axial direction. It consists of 41. The yoke 38 is a cylindrical magnetic member that is fitted into the solenoid chamber 16 so that its outer circumferential surface contacts the inner circumferential surface of the solenoid chamber 16. Further, the fixed core 39 covering the inner circumferential surface of the coil 37 is a substantially cylindrical magnetic member having a tapered portion 43 on the upper end surface, which is fitted into the center hole of the bobbin 42, and the center thereof is connected to the shaft. 24 is movably penetrated therethrough. The first side plate 23 is a ring-shaped magnetic member that covers the upper end surface of the coil 37 with its outer circumferential surface in contact with the inner circumferential surface of the solenoid chamber 16. 21 and the outer peripheral edge of the leaf spring 33 are airtightly sandwiched and fixed, and the movable plunger 41 reciprocates within the central opening thereof. The second side plate 40 is a ring-shaped magnetic member that covers the lower end surface of the coil 37 with its outer peripheral surface in contact with the inner peripheral surface of the solenoid chamber 16, and the lower end of the fixed core 39 is fitted into its central opening. It is inserted and holds the fixed core 39. Movable plunger 4
Reference numeral 1 denotes a substantially cylindrical magnetic member having a recess 44 shaped to fit into the tapered portion 43 of the fixed core 39 at the lower end, and the shaft 24 is fixed to the center thereof.

The sub-housing 45, which is fitted and fixed to the lower end of the housing 11, supports the electromagnetic solenoid 36, the second side plate 40, and the leaf spring 34 from below, and also supports the peripheral edge of the leaf spring 34 from the second side plate. 40 and the sub-housing 45. Sub housing 4
5 and the end of the shaft 24, the shaft 24 is moved in a direction (upward) against the elasticity of the spring 27 due to the elasticity of the spring 46.
is energized by

In FIG. 2, an electronic control unit (hereinafter referred to as
An ECU 47 is connected to a fluid control solenoid valve 10. The ECU 47 also receives signals from the engine speed sensor, engine water temperature sensor, intake air temperature sensor, and O2 sensor. In this embodiment, the inlet 12 and the outlet 1
3 and the communication port 14, and the spring 46, the leaf springs 33, 34, and the bellows 20 form the valve body 1.
A first biasing member is configured to bias the seat 7 in the seating direction.

Next, the operation of the fuel evaporative emission prevention device constructed as described above will be explained. The ECU 47 controls the fluid control solenoid valve 10 based on the engine speed, engine water temperature, intake air temperature, and a signal from the O2 sensor. In other words,
When no current is supplied to the coil 37, the combined force of the elasticity of the upper and lower springs 27, 46 and the leaf springs 33, 34 pushes the shaft 24 upward in FIG.
Push up the valve body 17 that is locked at the tip of the valve body 1
The rubber packing 19 inserted into the annular groove 18 of No. 7 is pressed against the valve seat portion 15. Therefore, the communication port 14 is closed and the inflow port 12 and the outflow port 13 are cut off. FIG. 1 shows this state.

When a current is supplied to the coil 37, the fixed core 39 moves from the second side plate 40 to the yoke 3.
8. A magnetic field forming a loop passing through the first side plate 23 and the movable plunger 41 and returning to the fixed core 39 is generated, and an attractive force is generated between the fixed core 39 and the movable plunger 41. Due to this suction force, the shaft 24 and the valve body 17 are pulled down together with the movable plunger 41 to a position where the elasticity of the springs 27, 46 and the leaf springs 33, 34 are balanced, and a gap is created between the valve seat part 15 and the rubber packing 19. The fluid (air) flows from the inlet 12 to the outlet 13. When a larger current is supplied to the coil 37, the valve body 17 is further pulled down, and the valve seat 15
The gap between the rubber packing 19 and the rubber packing 19 increases, and the flow rate to the outlet 13 increases.

In the state shown in FIG. 1, the pressure on the inlet 12 side is guided into the bellows 20 through the through hole 35 and acts in a direction to push up the valve body 17, which is integrated with the bellows 20, upward in the figure. Further, the pressure on the inlet 12 side also acts on the outside of the bellows 20, and acts in a direction to push down the valve body 17, which is integrated therewith, downward in the figure. The directions of the forces acting on the inside and outside of the bellows 20 due to the pressure on the inlet 12 side are opposite to each other. The force pushing the valve body 17 downward in the figure is proportional to the effective inner diameter of the rubber packing 19, and the force pushing the valve body 17 upward in the figure is proportional to the effective inner diameter of the bellows part 32 of the bellows 20. In addition, the pressure on the outlet 13 side is a force that acts on the valve body 17 from the outside in a direction pushing it upward in the figure, and a force that acts on the bellows portion 32 of the bellows 20 to push the valve body 17 upward.
is a force that acts in a downward direction in the figure, and these forces are proportional to the effective inner diameter of the rubber packing 19 and the effective inner diameter of the bellows portion 32 of the bellows 20, respectively. Therefore, due to the pressure on the inlet 12 side and the pressure on the outlet 13 side, a resultant force that pushes the valve body 17 downward in the figure and a resultant force that pushes it upward in the figure oppose each other. Therefore, by setting the dimensions of the effective inner diameter of the bellows portion 32 of the bellows 20 and the effective inner diameter of the rubber packing 19 so that these opposing forces match, the difference between the pressure on the inlet 12 side and the pressure on the outlet 13 side can be reduced. The force exerted by the pressure on the valve body 17 that opens and closes the communication port 14 can be canceled. Therefore, when operating the valve body 17, the valve body 17 is completely unaffected by the differential pressure between the pressure on the inlet 12 side and the pressure on the outlet 13 side, and the valve body 17 is not affected by the pressure difference between the pressure on the inlet 12 side and the pressure on the outlet port 13 side. The flow rate of the fluid can be accurately controlled according to the amount.

When fuel evaporative gas (gasoline vapor) flows in, the rubber packing 19 of the valve body 17 swells. Then, the volume of the rubber packing 19 increases and protrudes from the annular groove 18, and the valve body 17 and shaft 24 are pushed down. As a result, the leaf springs 33 and 34, the spring 46, which apply a biasing force to the valve body 17 in a direction opposite to the magnetic force of the coil 37,
The deflection of the bellows 20 increases, and the combined force thereof increases. On the other hand, when fuel evaporation gas (gasoline vapor) flows in, the rubber plate 29 also swells and its volume increases, and the deflection of the spring 27 increases. As a result, the urging force on the valve body 17 in the same direction as the magnetic force of the coil 37 increases, and the valve body
An increase in the resultant force in the opposite direction to the magnetic force of the coil 37 applied to the coil 37 is canceled, making it possible to accurately displace the valve body 17 with a predetermined current value, and thereby accurately controlling the flow rate of the fluid.

This will be explained using the modeled diagram of the force acting on the valve body 17 in FIG. 4 as follows. In the same figure, from the state before swelling of the rubber packing 19 and the rubber plate 29 shown by the dashed line to the state after swelling shown by the solid line, the valve body 17 has a predetermined amount ΔL1, and the rubber plate 29 has a predetermined amount ΔL1.
2 displacement. At this time, before the rubber packing 19 swells, the biasing member A1 is placed in the direction in which the valve body 17 is seated.
A biasing force F1 (=C1×L; where C is a spring constant and L is a length) is added, and after swelling, a biasing force F1' {=C
1×(L+ΔL1)} is added, and the difference in biasing force ΔF1
becomes C1×ΔL1. On the other hand, in the direction in which the valve body 17 is unseated, a biasing force F2 (=C2×L) is applied by the biasing member A2 before the rubber plate 29 swells, and a biasing force F2′ {=C2×( L-ΔL1+ΔL2)} is added, and the difference in biasing force ΔF2 is C2×(-ΔL1+ΔL2)
becomes. Then, it may be set so that ΔF1=ΔF2, that is, C1×ΔL1=C2×(−ΔL1+ΔL2).

As described above, the fluid control solenoid valve 1 of this embodiment
0, the fluid passage (inlet 12, outlet 13, communication port 1
4) a housing 11 having a valve seat portion 15 formed in the middle of the fluid passage;
A valve body 17 supported movably in the seating and unseating directions with respect to the valve seat portion 15, and a first biasing member (spring 46, leaf springs 33, 34, bellows) that biases the valve body 17 in the seating direction. 20), a second biasing member (spring 27) that biases the valve body 17 in the unseating direction, and a biasing force in the seating direction of the valve body 17 due to the difference in biasing force between the first and second biasing members. An electromagnetic solenoid 36 that moves the valve body 17 away from the valve seat 15 against force.
, an annular swellable rubber packing 19 (sealing member) disposed at the abutting portion of the valve body 17 with the valve seat portion 15 , and a rubber packing 19 disposed on the second biasing member.
A rubber plate 29 (characteristic correction member) having swelling properties for correcting the valve opening characteristics due to swelling of the valve was provided. As a result, the valve body 17 is seated by the biasing force in the seating direction due to the difference between the biasing forces of the first and second biasing members, and the portion of the valve body 17 that contacts the valve seat portion 15 is covered with a rubber packing. It is sealed at 19. Then, the electromagnetic solenoid 36 causes the first
The valve body 17 is unseated from the valve seat portion 15 against the biasing force in the seating direction of the valve body 17 due to the difference between the biasing forces of the second biasing member and the second biasing member. At this time, when the rubber packing 19 swells, the rubber plate 29 also swells, and the valve opening characteristic accompanying the swelling of the rubber packing 19 is corrected. Therefore, even if the rubber packing 19 having swelling property swells, a flow rate corresponding to the current value can be accurately ensured.

It should be noted that the present invention is not limited to the above-mentioned embodiment. For example, the rubber packing 19 as a sealing member was provided on the valve body 17 in the above embodiment, but the rubber packing 19 was provided on the valve body 17 as a sealing member.
may be provided. Further, the rubber plate 29 as a characteristic correction member may be arranged on the lower end side of the spring 27 in FIG. 1 (between the lower end of the spring 27 and the valve body 17).

Furthermore, the present invention may be embodied in a fluid control solenoid valve as shown in FIG. 5, or as a fluid control solenoid valve without bellows as shown in FIG.

[0023]

[Effects of the Invention] As detailed above, according to the present invention,
Even if the swellable sheet member swells, it exhibits an excellent effect of accurately ensuring a flow rate according to the current value.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a fluid control solenoid valve according to an embodiment.

FIG. 2 is a diagram showing the overall configuration of a fuel evaporative gas diffusion prevention device.

FIG. 3 is a partially enlarged view of the fluid control solenoid valve of the embodiment.

FIG. 4 is a diagram modeling the force acting on the valve body.

FIG. 5 is a sectional view of another example of a fluid control solenoid valve.

FIG. 6 is a sectional view of another example of a fluid control solenoid valve.

FIG. 7 is a cross-sectional view of a fluid control solenoid valve for explaining the prior art.

FIG. 8 is a diagram showing the relationship between current value and flow rate.

FIG. 9 is a diagram showing the relationship between current value and flow rate.

[Explanation of symbols]

10 Fluid control solenoid valve 11 Housing 12 Inlet 13 forming a fluid passage Outlet 14 forming a fluid passage Communication port 15 forming a fluid passage Valve seat 17 Valve element 19 Rubber packing 20 as a sealing member First
Bellows 27 constituting the biasing member Spring 29 as the second biasing member Rubber plate 33 as the characteristic correction member Leaf spring 34 constituting the first biasing member
Leaf spring 36 constituting the first biasing member Electromagnetic solenoid

Claims (1)

[Claims] Claims: 1. A housing having a fluid passage and a valve seat formed in the middle of the fluid passage, and a housing disposed within the housing and supported movably in seating and unseating directions with respect to the valve seat. a first biasing member that biases the valve body in the seating direction, a second biasing member that biases the valve body in the unseating direction, and the first and second biasing members. an electromagnetic solenoid for separating a valve body from a valve seat portion against a biasing force in a seating direction of the valve body due to a difference in biasing forces between biasing members; an annular swellable sealing member disposed at the contact portion; and a swellable characteristic correction member disposed at the second biasing member for correcting valve opening characteristics due to swelling of the sealing member. A solenoid valve for fluid control characterized by comprising: