JPH0642670A - Three-way control valve incorporating check valve - Google Patents

Abstract

PURPOSE:To provide a three-way flow control valve which is highly resistant to dust, having a high durability, which always stably actuate with no erroneous operation even though the pressure is unexpectedly increased, so as to be reliable, and which has a small-sized valve body. CONSTITUTION:A first spherical valve element 1 is located in a valve body 1 so as to be movable between a first position in which an actuating member communicates a load port (b) with a pressure supply port (a) but isolates the load port from a return port, and a second position in which the member communicates the load port (b) with the return port. Further, a second spherical valve element 20 is provided in the valve body, which abuts against the first spherical valve element 11 at the first position so as to hold the communication between the load port and the pressure supply port when the pressure of the supply port is higher than that of the load port but to close the pressure supply port in order to isolate the communication with the load port when the pressure of the supply port is lower than that of the load port, and which closes the load port at the second position so as to cut off the communication between the load port and the pressure supply port.

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 a conventional technique, for example, Japanese Patent Publication No. 49-10
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. 5 is publicly known as one having a check function, but in this case, since the check valve is incorporated in the inside of the boppet, the processing is complicated and expensive. Further, since it has a sliding portion, there is a problem that the structure is vulnerable to so-called dust such as valve sticking due to dust. An object of the present invention is to solve these problems, and a so-called dust-resistant structure is formed by eliminating sliding parts due to fitting and fitting sliding of a boppet valve, etc., high durability, and unexpected pressure. The present invention is to provide a three-way fluid control valve with a check valve, which is highly reliable and capable of always obtaining stable operation without an erroneous operation with respect to the rise of the valve, the valve body can be made small, and 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 spherical valve body to the first position to allow the load port to communicate with the pressure supply port. Block communication with the return port. At this time, the first spherical valve body abuts the second spherical valve body to allow 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, and vice versa. Closes the pressure supply port to prevent backflow and acts as a check valve.

When the operating member is in the inoperative state,
The second spherical valve element blocks the communication between the load port and the pressure supply port by the self-pressure of the pressure supply port, and the first spherical valve element is the second
The load port and the return port are allowed to communicate with each other by being moved to the position, and the load port and the return port are operated so that there is a stable flow of pressure oil without leakage from the pressure supply port. Since the first and second spherical valve elements roll without sliding,
There was no sticking due to dust and the durability was high. 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 Referring to FIG. 1 showing an embodiment of the present invention, a housing body 2 of a valve body 1 has a pressure supply port a and a contact portion 26 of a steel ball 10 which is a second spherical valve body. A seat 27 and a spacer 3 having no port hole for fluid flow in and out, and a seat 7 having a load port b in the middle and two steel ball contact portions 5 and 6 on both left and right sides.
In addition, a spacer 4 having a return port c is inserted. The fluid switching portion of the valve is constructed by inserting two steel balls 10 and 11 for switching the fluid into the two cylindrical spaces 8 and 9 formed by the inner diameter portions of the spacer 3 and the spacer 4 described above. It

There is a triangular groove between the spacers 3 and 4 and the sheets 27 and 7, 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. Bush rod
That is, the operating member 18 is a component for transmitting the stroke displacement of the movable iron core 19 to the steel ball 11 which is the first spherical valve body. Also,
An O-ring 20 is inserted in the solenoid guide 16 to seal the outside. The components such as the coil case 21, the coil 22, the yoke 23, the manual pin 24, the coil mounting nut 25, etc., which constitute the solenoid 30, 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 can be 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 of the contact portion 5 of the seat 7 and the opening 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 diameter of the sheet 7 is 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 and the supply port a
Is closed. The other steel ball 11 is pressed against the fixed iron core 15 side. As a result, load port b and return port c
Is connected. Next, when the solenoid 30 is excited,
Since the movable iron core 19 is attracted to the fixed iron core 15, stroke displacement occurs, and this stroke displacement is transmitted to the steel ball 11 via the push rod 18, and the steel ball 11 is pressed against the hitting portion 6 of the seat 7. As a result, the return port c is closed.
At the same time, as a result of the stroke displacement being transmitted to the other steel ball 10, 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 due to 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 has the function of a check valve. If the non-excited state is reached again, the steel ball 10 is pressed against the contact portion 5 of the seat 7 by the supply pressure.
It returns to the state of FIG. 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 shows an embodiment of the present invention different from that of FIG. 1, in which a small steel ball 13 is inserted into a hole 12 provided in a seat 7 ', and the movement of the steel balls 10 and 11 is carried out through the small steel ball 13. Is transmitted to the other party. By doing so, the sheet 7'can be made thicker, so that the size of the steel balls 10, 11 can be made smaller, it can be used at a higher pressure, and stable movement of the steel balls 10, 11 can be obtained.
FIG. 4 shows a further embodiment of the present invention in which a push pin 29 is inserted into the hole 12 'of the seat 30' in place of the small steel ball 13 of FIG. The hole 12 'is sized to guide the pin 29, and the oil passages 31 and 31 are provided on both sides of the hole 12'.
It operates more reliably.

[0014]

As described above, the spherical valve element of the present invention, that is, the steel ball 1
Since 0 and 11 have no sliding parts, they are extremely resistant to dust and have high durability and reliability. Further, since there is no sliding portion, no grinding process is required, so each part is easy to manufacture, and since only two valve bodies can be formed, the valve body can be made smaller and the valve can be made extremely small. It is possible,
It can be made extremely low in price. Load port b
Since there is no spring that presses the steel ball 10 when the steel ball 10 is closed, the force of the solenoid 30 is small, and there is no spring that presses the steel ball 10 when the steel ball 10 closes the supply port a. There is no pressure loss of the pressure oil flowing from the supply port a into the space 8 which is an oil chamber and flowing to 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 is 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 the supply port a ends,
Immediately, the pressure of the space 8 which is the oil chamber becomes the pressure of the pressure supply port a, and the positions of the steel balls 10 and 11 can be immediately switched by exciting the solenoid 30. In other words, it is possible to obtain stable, reliable, and quick operation without malfunction, and this is also highly reliable. Therefore, the switching frequency is 100 cycle / se
It can be used for pulse width control that requires extremely high switching frequency such as c, that is, stable operation can always be obtained without malfunction, and it is highly reliable in this respect.

[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 of an essential part corresponding to FIG. 1 of a third embodiment of the present invention.

FIG. 5 is a sectional view showing a conventional technique.

[Explanation of symbols]

 1. ． Valve body 10. ． Steel ball (second spherical valve body) 11. ． Steel ball (first spherical 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 (3)

[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 spherical valve body movably arranged in the valve body between a second position allowing communication, and a spherical valve body receiving the pressure of pressure oil of the pressure supply port and being in the first position. When the pressure of the pressure supply port is higher than the pressure of the load port by directly contacting with, the communication between the load port and the pressure supply port is maintained,
In the opposite case, the pressure supply port is closed so that the communication between the pressure supply port and the load port is cut off, and at the second position, the load port is closed so that the communication between the pressure supply port and the pressure supply port is cut off. A two-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 second spherical valve body is indirectly contacted with the first spherical valve body via an intermediate member. 3. The three-way fluid control valve with a check valve according to claim 2, wherein the intermediate member is a push pin or a small steel ball having a diameter smaller than that of the first spherical valve body.