JPH0726697B2 - Electromagnetic fluid switching valve - Google Patents

Description

The present invention relates to an electromagnetic switching valve, and more particularly to an electromagnetic switching valve that controls opening and closing of a fluid passage in response to an input current signal. The present invention relates to a fluid switching valve. In particular, it is used for switching a negative pressure circuit in an exhaust gas purifying device for an automobile engine.

(Prior Art) Conventionally, as an example of this type of electromagnetic fluid switching valve,
The one disclosed in Japanese Patent Publication No. 50-100132 is already known.

In this electromagnetic fluid switching valve, when a current is supplied to a solenoid coil by an input current signal, a magnetic circuit is formed between the inner core and a magnetic body outer peripheral yoke by the exciting action of the coil, and a plunger located in the magnetic circuit is formed. Is sucked into the inner core. As a result, the valve body fixed to the plunger moves integrally with the plunger, and the valve body separates from the valve seat surface, and the two ports communicate with each other.

When the current to the solenoid coil is cut off, the return spring that urges the valve body in the direction against suction to the inner core moves the valve body together with the plunger until it contacts the valve seat surface. Communication between them is cut off.

(Problems to be Solved by the Invention) In the above-mentioned conventional electromagnetic fluid switching valve, when it is used for switching a negative pressure circuit having a large flow rate, for example, it is necessary to increase the fluid passage area and seal the valve body. The area inevitably increases. Therefore, it is unavoidable that the suction force (proportional to the product of the seal area and the negative pressure) due to the pressure difference between the front and rear of the valve body increases, and in order to overcome this suction force and control the opening and closing of the valve body. However, there is a problem in that an electromagnetic mechanism that generates a large electromagnetic force is required, which increases the number of turns of the solenoid coil and thus increases the size of the electromagnetic fluid switching valve.

Therefore, it is a technical object of the present invention to enable it to be used for switching a negative pressure circuit having a large flow rate without requiring an electromagnetic mechanism that generates a large electromagnetic force.

[Structure of Invention]

(Means for Solving Problems) Technical means taken to solve the above-mentioned problems of the prior art include a body having an inlet port and an outlet port, and a fluid formed in the body and communicating between both ports. A passage and an outer peripheral yoke made of a magnetic material fixed to one end of the body,
An inner core arranged on the axis of the outer peripheral yoke, and a bobbin made of a non-magnetic material inserted and fixed to the outer periphery of the inner core,
A solenoid coil wound around a bobbin to form a magnetic circuit together with an outer peripheral yoke and an inner core; a first valve seat forming a working chamber that can communicate with an output port between one end surface of the inner core; and a first valve at one end. Is detachably attached to the seat and the other end is disposed in the action chamber so as to form a magnetic gap between the other end and one end surface of the inner core, and the first coil is excited when the solenoid coil is excited.
A first valve body that separates from the valve seat to connect the working chamber and the output port and sits on the first valve seat when not excited to block communication between the working chamber and the output port, and a body to face the fluid passage. The second valve seat formed on the second valve seat and the second valve seat are detachably coupled to the first valve body and have the same seal diameter as the seal diameter of the first valve body, and when the solenoid coil is excited. A second valve body that separates from the second valve seat to open the fluid passage and also sits on the second valve seat when not excited to close the fluid passage, and a direction in which the first valve body sits on the first valve seat. It is composed of a return spring for urging the valve and a pressure transmission hole formed in the first and second valve bodies so that the inlet port and the working chamber are always communicated with each other.

(Operation) The operation of the above technical means will be described below.

When the solenoid coil is not excited, the first valve body is seated on the first valve seat and the second valve body is seated on the second valve seat, so the working chamber is blocked from the outlet port and both The fluid passage communicating with the port is also closed. For this reason,
The fluid flowing from the inlet port is not supplied to the outlet port via the fluid passage.

At this time, the fluid pressure flowing from the inlet port acts on the second valve body, but since the pressure receiving area at that time becomes the sealing area of the second valve body, the force acting on the second valve body by the fluid pressure. Is (fluid pressure) × (seal area of the second valve body).
The direction of this force is such that if the fluid pressure is positive, the second valve body is disengaged from the second valve seat, and if the fluid pressure is negative, the second valve body is seated on the second valve seat. Next, the fluid pressure also acts on the working chamber via the pressure transmission hole, but at this time,
On the inner core side end surface of the first valve body, (fluid pressure) × (first
The force represented by the pressure receiving area of the inner core side end surface of the valve element acts in a direction opposite to the force acting on the second valve element, and the first valve seat side end surface exposed to the working chamber of the first valve element is (Fluid pressure) x (first
The force represented by the pressure receiving area of the first valve seat side end surface exposed to the action chamber of the valve body acts in the same direction as the force acting on the second valve body. That is, in the first valve body, (fluid pressure) x [(pressure receiving area of the inner core side end surface of the first valve body)-(first valve seat side end surface exposed to the working chamber of the first valve body). ] = (Fluid pressure)
The force represented by x (the seal area of the first valve body) acts in the opposite direction to the force acting on the second valve body.

Here, since the seal diameter of the first valve body is the same as the seal diameter of the second valve body, the seal area of the first valve body becomes equal to the seal area of the second valve body, and as a result, due to the fluid pressure, The force acting on the first valve body is balanced with the force acting on the second valve body by the fluid pressure. Therefore, when the solenoid coil is not excited,
The force acting on the second valve element is only the biasing force of the return spring.

When the solenoid coil is excited, the first valve body is attracted to the inner core through the magnetic gap,
The valve body moves in a direction against the biasing force of the return spring. As a result, the fluid passage is opened, the fluid pressure from the inlet port is supplied to the outlet port, and the working chamber communicates with the outlet port so that the fluid pressure in the working chamber is also supplied to the outlet port.

(Example) Hereinafter, the Example which actualized this invention is described based on an accompanying drawing.

The electromagnetic fluid switching valve 10 according to the present invention includes a body 17, and an inlet port 22 communicating with a negative pressure source and an outlet port 23 communicating with an exhaust gas purifying device. Both ports 2
2, 23 communicate with each other through fluid passages 31, 32 formed in the body 17, and a seat member 18 made of a non-magnetic material between the passages 31, 32 and a first valve body 13 integrally connected Also, the second valve body 11 is provided, and the seal portions 12 and 14 made of rubber material of the respective valve bodies can contact the seat surfaces 26 and 27 at the same time, thereby controlling the opening / closing between the ports 22 and 23. To be done.

An outer peripheral yoke made of a magnetic material is provided at the right end of the body 17 in the figure.
19, 20 are fixed, and an inner core 30 is arranged on the central axis in the yokes 19, 20. A bobbin 29 made of a non-magnetic material is inserted and fixed to the outer periphery of the inner core 30, and the solenoid coil 15 is wound on the bobbin 29. When current is supplied to the solenoid coil, the inner core 30 and the outer peripheral yoke 1
A magnetic circuit is formed by 9, 20 and the first circuit is formed in the magnetic circuit.
The valve body 13 is located. A sleeve 28 for guiding the first valve body 13 is inserted and fixed between the inner core 30 and the bobbin 29. The first valve body 13 has a first through hole 33 coaxial with the inner core, and the first through hole 33 has a second through hole 34 in the same axial direction as that of the second valve body 11. The tubular portion penetrates the sheet member 18 and is press-fitted and fixed. As a result, the first valve body 13 and the second valve body 11 are integrated, and the return spring 21 disposed between the first valve body 13 and the inner core 30 causes the seal portions 12 and 14 of the respective valve bodies to move to the respective seat surfaces 26. , 27 are simultaneously urged in such a direction as to abut.

Since the seal portions 12 and 14 of the two valve bodies come into contact with the seat surfaces 26 and 27 at the same time, the seal portion 12 of the second valve body 11 is seated on the seat surface.
In the state of being in contact with 26, the first valve body 13 is pressed into the tubular portion of the second valve body 11 until the first valve body 13 comes into contact with the seat surface 27. At this time, since the seal portions 12 and 14 of each valve body are made of a rubber material having an equivalent elastic coefficient, the seal portions 12 and 14 and the valve bodies 11 and 13 and the seat surfaces 26 and 27 are in contact with each other. The distance between the seat surfaces 26 and 27 is the same. Due to the above, the two valve bodies 1 integrated
1, 13 surely contact the seat surfaces 26, 27 at the same time.

Next, the operation of the above structure will be described. When the negative pressure from the negative pressure source is transmitted to the input port 22, the second valve body 11 has (negative pressure) × (seal area of the second valve body 11).
The suction force represented by is applied to the left in the figure.

At the same time, the negative pressure is transmitted to the working chamber 25 via the pressure transmission hole 24. Then, the suction force represented by (negative pressure) × (pressure receiving area of the inner core side end surface of the first valve body 13) acts on the inner core side end surface of the first valve body 13 in the right direction in the drawing. At the same time, since the negative pressure is also transmitted to the gap between the seat portion 18 located on the outer peripheral side of the seal portion 14 and the first valve body 13 via the pressure transmission passage 16, the first valve body 13 is A suction force represented by (negative pressure) × (pressure-receiving area of the seat portion side end surface facing the gap of the first valve body 13) acts on the seat portion side end surface facing the gap in the left direction in the drawing. That is, in the first valve body 13,
(Negative pressure) x [(pressure receiving area of the inner core side end surface of the first valve body 13)-(pressure receiving area of the seat side end surface facing the gap of the first valve body 13)] = (negative pressure) x first valve The suction force represented by the seal area of the body 13 acts in the right direction in the drawing.

Here, since the seal diameter of the first valve body 13 is the same as the seal diameter of the second valve body 11, the seal area of the first valve body 13 is equal to the second valve body.
The suction area acting on the first valve body 13 due to the negative pressure is equal to the suction area acting on the second valve body 11 due to the negative pressure. Therefore, the solenoid coil
The force acting on the first and second valve bodies 12 and 11 when 15 is not excited is only the biasing force of the return spring. Accordingly, a current is supplied to the solenoid coil 15, and the exciting action of the coil 15 attracts the first valve body 13 located in the magnetic circuit formed between the inner core 30 and the magnetic body outer peripheral yokes 19 and 20 to the inner core. The electromagnetic force required for the solenoid coil 15 is approximately equal to the elastic force of the return spring 21.
The number of turns can be reduced, and the size of the electromagnetic fluid switching valve can be reduced.

〔The invention's effect〕

In the present invention, since the force acting on the first and second valve bodies when the solenoid coil is not excited is only the biasing force of the return spring, the electromagnetic force required to open both valve bodies is
It may be approximately equal to the biasing force of the return spring. Therefore, even in the electromagnetic fluid switching valve having a large flow rate, it is not necessary to increase the number of turns of the solenoid coil, and the size of the electromagnetic valve does not increase.

Further, since the force that presses both valve bodies against each valve seat when the solenoid coil is not excited is only the biasing force of the return spring, the force that presses both valve bodies against each valve seat is relatively small. The durability is improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an electromagnetic fluid switching valve according to the present invention. 10 …… Electromagnetic fluid switching valve, 11 …… Second valve body, 13 …… First valve body, 12,14 …… Seal surface, 15 …… Solenoid coil, 17 ……
Body, 19, 20 …… Outer yoke, 21 …… Return spring, 22 …… Inlet port, 23 …… Outlet port, 24 …… Pressure transmission hole, 26,27 …… Seat surface, 29 …… Bobbin, 30… … Inner core, 31,32 …… Fluid passage

Claims (1)

[Claims] 1. A body having an inlet port and an outlet port, a fluid passage formed in the body for communicating between the both ports, an outer peripheral yoke made of a magnetic material fixed to one end of the body, An inner core arranged on the axis of the outer yoke, a bobbin made of a non-magnetic material inserted and fixed to the outer periphery of the inner core, and a solenoid wound around the bobbin to form a magnetic circuit together with the outer yoke and the inner core. A first valve seat that forms a working chamber that is capable of communicating with the output port between the coil and one end surface of the inner core; one end is detachably attached to the first valve seat and the other end is one end surface of the inner core Is disposed in the working chamber so as to form a magnetic gap between the working chamber and the output port by separating from the first valve seat when the solenoid coil is excited. A first valve body that is in communication with the first valve seat when not excited and blocks communication between the working chamber and the output port; and a second valve seat formed in the body so as to face the fluid passage. And detachably attached to the second valve seat integrally with the first valve body, and has the same seal diameter as the seal diameter of the first valve body, and the second valve when the solenoid coil is excited. A second valve body that separates from the seat to open the fluid passage and sits on the second valve seat to close the fluid passage when de-energized; and seats the first valve body on the first valve seat. An electromagnetic fluid switching valve including a return spring biased in a direction, and a pressure transmission hole formed in the first and second valve bodies so as to always communicate the inlet port with the working chamber.