JPH0771642A - Three-way fluid control valve with check valve - Google Patents

Abstract

PURPOSE:To provide stable action with no misoperation against an abnormal rise of pressure by eliminating a sliding part, and forming a so-called structure strong against dust, in a fluid control valve provided with a check function for preventing a reverse flow from a load port to a pressure supply port in a 3-port 2-position valve. CONSTITUTION:In the case of non-excitation of a solenoid 30, a fluid flows in from a pressure supply port (a), but a steel ball 10 is pressed to a seat 7 by a supply pressure to close a flow path, and another steel ball 11 is pressed to a side of a fixed core 15. As a result, a load port (b) and a return port (c) are placed in a communication condition. Next by exciting the solenoid 30, when a movable core 19 is attracted, the steel ball 11 is pressed to the seat 7 through a push rod 18, to close the return port (c). Simultaneously by displacing the other steel ball 10, the supply port (a) and the load port (b) are made to be placed in a communication condition. Under this condition, when a pressure higher than the supply pressure is applied from the load port (b), the steel ball 10 is pressed to a seat 27 to function as a check valve.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid control valve provided with a check function for preventing a backflow from a load port to a pressure supply port in a 3-port 2-position valve for controlling a working fluid by electromagnetic force. The present invention relates to a three-way fluid control valve with a check valve having a valve structure of a fluid switching unit.

[0002]

2. Description of the Related Art As conventional technology, for example, Japanese Patent Publication No.
371 or JP-A-60-44671. Both of these techniques are characterized by the valve structure balancing fluid pressure. For this reason, the number of parts is increased and a special shape is required for the shape of the parts, and more precise processing is required.

[0003]

Although these techniques are 3-port 2-position valves, they do not have the above-mentioned check function,
A check valve must be provided in the circuit to prevent backflow from the load port to the supply port. Further, the one shown in FIG. 4 is known as the one with the check function, but in this case, since the check valve is incorporated in the inside of the boppet, the processing is complicated and expensive. In addition, there is a problem that the structure is weak against so-called dust such as valve sticking due to dust because it has a sliding portion. The present invention has an object to solve these problems, and fits a boppet valve, etc., and eliminates sliding parts due to fitting and sliding to have a so-called dust-resistant structure, has high durability, and has an unexpected pressure. It is an object of the present invention to provide a three-way fluid control valve with a check valve, which is highly reliable because it can always obtain stable operation without malfunction due to rising, and has a small valve body, which is simple and inexpensive to manufacture.

[0004]

Therefore, the present invention has solved the above-mentioned problems of the prior art by providing a three-way fluid control valve with a check valve according to the claims.

[0005]

When the actuating member is in the actuated state by, for example, an electromagnetic device, the actuating member moves the first valve body to the first position to allow the load port to communicate with the pressure supply port and return. Block communication with the port. At this time the first
The valve body indirectly contacts the second valve body via the intermediate member and allows the flow of pressure oil from the pressure supply port to the load port when the pressure of the pressure supply port is higher than the pressure of the load port,
In the opposite case, the pressure supply port is closed to prevent backflow and act as a check valve.

When the operating member is in the inoperative state,
The second valve element cuts off the communication between the load port and the pressure supply port by the self pressure of the pressure supply port, the first valve element is moved to the second position, and the communication between the load port and the return port is allowed, and the load port It is operated so that there is a stable flow of pressure oil from the return port to the return port without leakage from the pressure supply port. First
Also, the second valve body did not slide, and there was no sticking due to dust, etc., and the durability was improved. Further, even when an abnormal pressure occurs in the pressure supply port, the communication with the load port is cut off, so that a malfunction is prevented.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIG. 1, in which a housing hole 2 of a valve body 1 is provided with a pressure supply port a and a contact portion 26 of a steel ball 10 which is a second valve body. A sheet 27 having the same, a spacer 3 having no port hole through which a fluid flows in and out, a sheet 7 having a load port b in the middle, and two steel ball contact portions 5 and 6 on both left and right sides, and an oil inside thereof. Inserted are the passages 31, 31 and a spacer 32 provided with a hole 12 dimensioned to guide the push pin 29, and a spacer 4 having a return port c. Into the two cylindrical spaces 8 and 9 formed by the inner diameters of the spacer 3 and the spacer 4, two steel balls 10 for switching the fluid and a steel ball 11 as the first valve body are inserted, ball
Push pin 29 between 10 and 11 in hole 12 of seat 32
Has been inserted.

The sheet 27, the spacer 3, the sheet 7,
There is a triangular groove between 7 and the spacer 4, and each O-ring 14 eliminates the leak in the housing. Each of the above-mentioned components is inserted and fixed in the valve body 1 by a tightening nut 17 via a fixed iron core 15 and a solenoid guide 16. The bush rod 18, that is, the operating member is a component for transmitting the stroke displacement of the movable iron core 19 to the steel ball 11 which is the first valve body. In addition, the solenoid guide 16 has an O-ring 20
Has been inserted to seal the outside. Coil case 21, coil 22, and yoke that make up the solenoid 30.
The parts such as 23, the manual pin 24 and the coil mounting nut 25 are the same as those of a general wet type solenoid.

The dimensions of the main parts will be described below. First, the opening S between the steel ball 11 and the contact portion 6 of the seat 7 in the non-excited state, and the distance between the movable iron core 19 and the fixed iron core 15 at that time. S'is the non-excited state, and the total length of the push rod 18 is determined so that S'is slightly larger than S. By doing so, the movable iron core 19 and the fixed iron core 15 are not completely attracted to each other even in the excited state, so the return port c
(Tank port) can be completely closed. Further, the opening S, the steel ball 10 and the seat in the non-excited state
The opening S ″ of the contact portion 26 of 27 is set to be 2 × S = S ″. By doing so, the steel ball 10 in the excited state
It is possible to make the opening degree of the contact portion 5 of the seat 7 and the opening degree of the steel ball 10 and the contact portion 26 of the seat 27 the same, and it is possible to make the pressure loss uniform.

The inner diameters of the sheets 7 and 7 are determined by the supply pressure and the suction force of the solenoid 30. That is, the steel ball 10 is pressed against the sheet 7 by the supply pressure P, but the pressing force F is F = P ·, where d is the inner diameter of the sheet 7.
(Π / 4) · d ² . If the suction force of the solenoid 30 is not larger than F, the valve will not operate. So sheet 7
Inner diameter d is Fs> F (Fs is the attraction force of the solenoid)
Will be decided.

Next, the operation will be described. The state shown in FIG. 1 is when the solenoid 30 is not excited. At this time, the fluid flows in from the pressure supply port a, but the steel ball 10 is pressed against the contact portion 5 of the seat 7 by the supply pressure and the supply port a is closed. The other steel ball 11 is pressed against the fixed iron core 15 side. As a result, the load port b and the return port c are in communication with each other. Next, when the solenoid 30 is excited, the movable iron core 19 is attracted to the fixed iron core 15 and thus stroke-displaced. It is pressed against the hit part 6. As a result, the return port c is closed. At the same time the steel ball through the push pin 29 to the other steel ball 10
As a result of transmission of the stroke displacement of 11, the supply port a and the load port b are in communication.

In this state, when a pressure higher than the supply pressure is applied from the load port b, the steel ball 10 is pressed by the seat 27 by the pressure.
Since it is pressed against the contact portion 26, the working fluid does not flow back to the supply port a. That is, it will have the function of a check valve. When the non-excited state is restored again, the steel ball 10 is pressed against the contact portion 5 of the seat 7 by the supply pressure.
Return to the state of. Since the return from the excited state to the non-excited state is performed by the pressure of the supply fluid, a return spring is not required.

FIG. 3 is a second embodiment of the present invention different from FIG. 1, in which small steel balls having a diameter smaller than that of the steel balls 10 and 11 are provided in the holes 12 'formed in the sheets 7'and 7'of the spacer 33. 13 is inserted so that the movements of the steel balls 10 and 11 are transmitted to each other through the other.

[0014]

As described above, the second and first valve bodies 1 of the present invention
Since 0 and 11 have no sliding parts, they are extremely resistant to dust and have high durability and reliability. Further, since the valve bodies 10 and 11 have no sliding portion, grinding is not required, each component can be easily manufactured, and the valve can be made extremely small, and the cost can be made extremely low. Further, the load port b is connected to the second valve body.
Since there is no spring for pressing the second valve body 10 when 10 is closed, the force of the solenoid 30 can be reduced, and the spring for pressing the second valve body 10 when the second valve body 10 closes the supply port a. Since there is not, space 8 which is an oil chamber from the supply port a
There is no pressure loss of the pressure oil flowing into the load port b and flowing into the load port b, and even if the pressure of the pressure oil is brought close to 0, a minute flow rate control without chattering becomes possible.

Further, since the pressure inside the solenoid guide 16 is always equal to the return port c (tank port) pressure, no special pressure-proof guide is required, which is also inexpensive.
Incidentally, even if the supply port a is unexpectedly increased in pressure, the valve does not open unlike the conventional example, which is safe.
Moreover, when the unexpected increase in pressure at load port b ends,
Immediately, the pressure of the space 8 which is the oil chamber becomes the pressure of the pressure supply port a, and the solenoid 30 is energized to make the second and first pressures.
The positions of the valve bodies 10 and 11 can be immediately switched. That is, it is possible to obtain stable, reliable, and quick operation without malfunction, and this is also highly reliable.
It can be used for pulse width control that requires an extremely high switching frequency of 100 cycles / sec, that is, it can always obtain stable operation without malfunction, and has an excellent effect in that it has high reliability.

[Brief description of drawings]

FIG. 1 is a sectional view of a three-way fluid control valve with a check valve according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of main parts taken along the line AA of FIG.

FIG. 3 is a sectional view of an essential part corresponding to FIG. 1 of a second embodiment of the present invention.

FIG. 4 is a sectional view showing a conventional technique.

[Explanation of symbols]

 1. ． Valve body 10. ． Steel ball (second valve body) 11. ． Steel ball (first valve body) 13. ． Small steel ball (intermediate member) 15. ． Fixed iron core (stopper) 18. ． Push rod (operating member) 29. ． Push pin (intermediate member) a. ． Pressure supply port b. ． Load port c. ． Return port

Claims (2)

[Claims] 1. A first position for allowing communication between a load port and a pressure supply port selectively provided by an actuating member and blocking communication with a return port, or between the load port and the return port. A first valve body movably disposed in the valve body between a second position allowing communication, and a first valve body that receives pressure of pressure oil of the pressure supply port and is in the first position. When the pressure of the pressure supply port is indirectly contacted via the intermediate member and the pressure of the pressure supply port is higher than the pressure of the load port, the communication between the load port and the pressure supply port is maintained, and in the opposite case, the pressure supply port is closed. A second valve body movably disposed within the valve body to block communication between the load port and the load port and close the load port in the second position to block communication between the load port and the pressure supply port. Features A three-way fluid control valve with a check valve. 2. The three-way fluid control valve with a check valve according to claim 1, wherein the intermediate member is a push pin or a small steel ball having a diameter smaller than that of the first valve body.