JPS59200881A - Solenoid valve - Google Patents

Abstract

PURPOSE:To make leakage between respective ports small enough and improve response by combining a torque motor with a seat type valve. CONSTITUTION:When a coil 7 is conducted, an armature 4 is attracted by the S-pole of a permanent magnet 3 and tries to swing clockwise. A pushing force due to a fluid pressure in a valve chamber 10 and the pushing force of a spring 18 effect on the armature 4, but the pushing force due to the fluid pressure P is cancelled by the fluid pressure of a pressure balance chamber 15. Accordingly, the armature 4 is swung clockwise by the pushing force of the spring 18 and a torque against a Bernoulli's hydraulic force. By utilizing the seat type valve 8, the opening degree of a valve port 11 may be enlarged sufficiently even in case the sliding stroke of the valve 8 is made considerably small. Further, the response in the opening direction of the valve may be improved since the opening degree of the valve port 11 may be enlarged sufficiently.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electromagnetic valve which is equipped with a torque motor and whose passages are opened, closed or switched by the operation of the torque motor.

Conventionally, a torque motor was used to switch passages, for example, as described in "Hydraulic and Pneumatic Design Vol. 18 No. 4 P.
11 (April 1980)".

The valve described here is configured as a direct-acting servo valve, and will be explained based on Fig. 11.
It is composed of a torque motor (105) and a spool-type valve (106), and more specifically, an armature (103) is swingably supported by a pin (102) in the magnetic field of a permanent magnet (101). ) and coil (104
), and the armature (103) is selectively swung clockwise or counterclockwise by switching the direction of direct current flowing through the coil (104) between forward and reverse. (105), and the valve body (113) includes a spool hole (107), a pump port (108), each cylinder port (109),
(110) and tank port) (111), and a spool type valve (111) in which a four-land type spool (11'2) connected to the armature (103) is slidably installed in the spool hole (107). 113). Then, by controlling the energization to the coil ('104), the operation of the spool (112) is controlled, and the communication state between the ports (108) to (111) is switched. This allows for directional control.

By the way, as shown in FIG. 11, the conventional electromagnetic valve configured as described above uses a spool type valve, so there is a lot of leakage between the ports (108) to (111), and the leakage is prevented. In order to suppress it within a certain range, it is necessary to increase the overlap between land and port.
As a result, the spool (112) during the switching operation
(7)! As a result, there is a problem that the responsiveness of the switching operation of the electromagnetic valve deteriorates and the valve performance decreases.

Furthermore, as mentioned above, when trying to suppress the leakage between the ports within a certain range, the response becomes poor, so a pulse width modulator is connected to this type of solenoid valve to control the valve in a very short period. Even if an attempt was made to control the flow of hydraulic oil by repeating the switching operation, there was a problem in that sufficient controllability could not be obtained.

The present invention was invented in view of the above-mentioned conventional problems, and aims to sufficiently reduce leakage between each port by combining a torque motor and a seat type valve.
Moreover, the opening/closing or switching operation of the passage can be performed with a small sliding stroke of the valve, thereby improving responsiveness.

In order to achieve this object, the present invention provides a construction in which a permanent magnet is provided in a housing, and a torque armature and a coil are disposed in the magnetic field of the permanent magnet and are supported swingably from a pivot pin. In addition to arranging a motor, a valve part having a valve chamber in which a seat-type valve is installed in the housing, a valve hole opened by the MiJ seat-type valve, and connection ports opened before and after the valve hole is formed. On the other hand, a moving body is provided between the swinging direction side of the armature and the seat-type valve to enable the seat-type valve to be operated by the operation of the armature; By installing a balance piston facing the pressure balance chamber that communicates with the valve chamber on the side and using the seat type valve, leakage between each port is minimized (and mJ can be recorded with a small sliding stroke). The valve can be opened and closed, and by applying the same fluid pressure as the valve chamber to the back of the balancing piston to balance the armature statically, the valve can be opened and closed with a small output from the torque motor. It was made so that it could be opened and closed.

Embodiments of the present invention will be described below based on the drawings.

First, the basic form of the present invention will be explained based on FIG.

Note that Figure $2 is a symbol diagram of the embodiment shown in Figure 1.

The one shown in Figures 1 and 2 is a two-position, one-way valve, and its basic structure consists of a torque motor (6) and a valve part (60) with a seat-type valve (8). consisting of Wl
The operation of the motor (6) is interlocked with the seat-type valve (8) via an interlocking body (14), and a balance piston (17) is provided to perform static pressure balancing. It is something.

The torque motor has a torque motor chamber (2) formed on the negative side of the housing (1), and a U-shaped permanent magnet (
6), and is swingably supported by a pivot pin (5) within the magnetic field of the permanent magnet (6),
7) is positioned outside the armature (4).

Further, the valve portion (60) forms a valve chamber (10) that opens one connection port (9) on the − side of the armature (4) in the swinging direction of the housing (1), and A valve hole (11) is provided on the armature (4) side of the valve chamber (10).
A valve seat body having a valve seat body and a connection chamber (16) that opens another connection port 1-(12) are formed, and the seat-type valve (8) is further installed inside the valve chamber (10). It is something.

Further, a sliding hole (14a) for the interlocking body (14) is formed between the connection chamber (16) of the housing (1) and the armature (4), and the sliding hole (14a) The interlocking body (1) is integrally formed with the seat-type valve (8).
4) is installed inside so that it can slide freely. And the interlocking body (1
By bringing the tip of the armature (4) into contact with the armature (4), the seat-type valve (8) can be opened and closed in conjunction with the swinging of the armature (4).

On the other hand, the armature (
4), a pressure balance chamber (15) is formed on the side opposite to the interlocking body (14), that is, on the other side in the swinging direction of the armature (4), and this pressure balance chamber (
A piston hole (16) for the balance piston (17) is formed between the armature (15) and the armature (4). The balance piston (17) is slidably housed in the chain hole (16). Furthermore, the back surface of the piston (17) faces the pressure balance chamber (15), and the tip of the piston (17) is brought into contact with the armature (4) so as to face the interlocking body (14). be.

Further, the pressure balance chamber (15) has a communication path (15a)
It communicates with the connection point (9) and, in turn, with the valve chamber (1o) via the armature (4), thereby statically pressure-balancing the armature (4).

That is, the seat diameter (dl) of the seat type valve (8) seated in the valve hole (11) of the valve seat body and the diameter (a) of the balance piston (17) are made the same diameter, The pressure receiving area (A) of the seat-type valve (8) in the valve chamber (10)
) and the pressure balance chamber (1) of the piston (17).
5) The pressure receiving area (A) in G is configured to be the same, and the valve chamber (10) and the pressure balance chamber (15) are configured to be the same.
) are communicated with each other through the communication path (15a), and the same fluid pressure (P) acting on each of these chambers (10) and (15) causes the interlocking body (14 and the balance The armature piston (1'7) is brought into contact with the armature (4) with the same force (pA+-''4), and the armature (4) can be statically balanced in pressure. In this balanced state, the seat valve (8) can be operated by the armature (4) with a small torque.

In addition, the seat diameter (d,) and mll of the seat type valve (8)
The diameters (tonnes) of the moving body 14) are made equal to each other, so that the fluid pressure acting on the seat-shaped valve (8) and the moving body (14) can be ignored in the connection chamber (16). That's what I do.

Furthermore, the one shown in FIG. 1 is provided with a spring (18) that presses the valve chamber (10) and the seat-type valve (8) into the valve hole (11), and demagnetizes the coil (7). This is done so that it returns to the neutral position. This spring (
18) is made stronger than the holding force by the permanent magnet (6), but may be lower than the holding force. In this case, in order to return to the neutral position, a current in the opposite direction may be passed through the coil (7).

In addition, the seat diameter (dl) and the balance piston (17
) does not necessarily have to be the same diameter as the piston diameter (d2), but may be different as long as the function of operating the seat type valve (8) at low output due to pressure balance is not lost. The diameter may be unbalanced in terms of pressure.

Further, the seat diameter is approximately 4φ to 10φ, and the sliding stroke due to the opening/closing operation of the seat type valve (8) is 0.5φ.
It is preferable to set it to about 10.

Next, the operation of the present embodiment shown in FIG. 1, constructed as described above, will be explained.

First, the case where the seat-type valve (8) is operated from closed to open will be described.

When the coil (7) is energized in the direction of the arrow (A) in Fig. 1, the lower part of the armature (4) becomes the north pole,
It is attracted to the S pole of the permanent magnet (6), and the armature (4
) tries to swing clockwise. At this time, the armature (4) is subjected to a pressing force (P-
A, ) and the pressing force of the return spring (18) are acting, but the pressing force (
""t) is the pressure balance chamber (15) as described above.
The fluid pressure (P) causes the balance piston (17
) is canceled out by the pressing force (P-A, ) in the left direction in Figure 1 that acts on the armature (4) through It can swing clockwise with torque that opposes Bernoulli's fluid force. Therefore, the solenoid valve of this embodiment can make the output of the torque motor (6) relatively small while using the seat type valve (8).

Moreover, since the seat type valve (8) is used, the valve (8)
The sliding stroke is quite small (0.5~i mm
) L, the opening degree of the valve hole (11) can be made sufficiently large. Moreover, the responsiveness in the opening direction is improved accordingly.

Next, to explain the case where the seat-type valve (8) is operated from the open state to the closed state, when the power supply to the coil (7) is cut off, the armature (4) is demagnetized, and the return Due to the pressing force of the spring (18) and the fluid force, the seat valve (8) is pushed back to the closed position and at the same time returns to the neutral position. Therefore, since the stroke is reduced by about half compared to the case of a spool-type configuration, the time required for the valve (8) to come to rest, especially in the closing direction, is also shortened.

As described above, since the torque motor (6) and the seat type valve (8) are combined, there is almost no leakage between the connecting ports (9) and (12) when the valve (8) closes. In addition, since the armature (4) is balanced in terms of 1, (+), the valve (4) can be operated with a relatively small output of the torque motor (6). 8) can also be opened and closed. Note that any flow direction (A 4 B) may be used. Also, leakage to the drain port can be solved by making the overlap arbitrarily long.

In the embodiment described above, the seat-type valve (8) is used as the main valve, but it may also be used as a pilot valve of the seat-type main valve (20) as shown in Figures 3 and 4.

Next, the second embodiment shown in FIGS. 6 and 4 will be explained. (The same parts as in the first embodiment are given the same reference numerals, and their explanations are omitted. Also, FIG. 4 shows the Shinholter 1 of the embodiment shown in FIG. 6.) FIG. 6 What is not shown in FIG. 1 constitutes a torque motor (6) and a valve part (6o) as in the first embodiment, and also combines a seat type main valve (20) to the valve part (50).
The main valve (20) is opened and closed by opening and closing the seat valve (8).
The main valve (2o) is opened and closed by controlling the pilot pressure to the main valve (2o).

The seat type main valve (20) has a valve body (21) and a valve (22).
) is freely slidable inside, and a square main port (23) and a side main port (24) are installed on one side of the valve (22) of the valve body (21), and a side main port (24) is installed on the other side. A rear pilot port (25) is formed in the rear pilot port (25).

In this embodiment, the pump line (P) is connected to the side main port (24) of the seat-type main valve (20), and the square main port of the main valve (20) (23) The cylinder line (A) is connected to.

On the other hand, an orifice (27) is interposed in a branch path branching from the pump line (P) to connect it to one connection port (12) in the valve section (60) that functions as a pilot valve, and to connect the other The contact M port (9) is connected to the cylinder line (A) to form a control circuit (28), and the outlet side of the orifice (27) of the circuit (28) is connected to the back pilot port 1-(25). Connect.

Then, the coil (7) is energized and the armature (4) is turned on.
) is rocked clockwise in the sixth position, the seat-type valve (
8) opens, and hydraulic oil flows into the suppression circuit (28). Then, since the orifice (27) is included in the control circuit (28), the pilot pressure acting on the rear pilot boat (25) decreases, and the valve pressure due to the differential pressure before and after the orifice (27) decreases. (22) When the above force exceeds the spring (26) ratio, the valve (22) opens and the side main port (24) and square main port (23) are brought into contact. .

Further, when the coil (7) is de-energized, the armature (4) returns to the neutral position and the seat-type valve (20
) is closed and the flow of the control circuit (28) is interrupted. As a result, the fluid pressure acting on the side main port (24) and the fluid pressure acting on the rear pilot port (25) become equal again, so that the valve (22) opens. , communication between the side main port (24) and the square main port (23) is cut off.

In this embodiment, by branching from the pump line (P) and returning the hydraulic oil flowing through the control circuit (28) to the cylinder line (A), energy loss can be reduced and This allows for good controllability.

In the above embodiment, one seat type valve (8) is combined with one torque motor (6), but the fifth
, 6 As shown in FIG. 6, one torque motor (6) is combined with four seat-type valves (8) to
6) for the operation of the armature (4), each of the seat valves (8)
) are interlocked to perform passage switching operations, 6 positions, 4 directions,
It may also be used as a counter argument. (In addition, the numbers indicated in Fig. 5 are the same as those in the first embodiment. Also, Fig. 6 is a symbol diagram of the embodiment shown in Fig. 5.) The numbers indicated in Fig. 5 are as follows: A torque motor (6) similar to the first embodiment is installed inside the housing (1), but in this embodiment, the armature (4) has a pair of interlocking bodies (1) at each end thereof.
4) It is possible to abut against each other in a facing manner.

Further, the housing (1) is provided with first to fourth valve parts (60) to (63) each having a seat type valve (8).
4), that is, four valve parts are provided, two of the valve parts (60) to (66) are placed opposite to each other, and the pivot pin of the torque motor (6) is connected to the pivot pin of the torque motor (6). It is located symmetrically.

Each of the first to fourth valve parts (60) to (66) is constructed similarly to the first embodiment, and includes a valve chamber (10) that opens one connection port (9), and a valve hole ( 11) and a connection chamber (11) opening into another connection boat (11).
16), and a seat-type valve (8) is slidably housed in the valve chamber (10).

On the other hand, this embodiment differs from the first embodiment in that the pressure/<lance g( 15) and an interlocking body (14) that allows the seat-type valve (8) and the armature to move.
), and the separated part is in contact with the pressure lance chamber (15), so that the interlocking body (14) also functions as the balance piston in the first embodiment. I try to do that. In addition, also in this example, the seat diameter (d,
) and the diameter (d2) of each interlocking body are made equal.

and each connection port (9) opening into each valve chamber (10), (1,0) of the first and second valve parts (30), (31),
(9) to the common pump line (P),
The pressure balance chambers (15), (15) provided corresponding to these valve parts (60), (61) are connected to the pump line CP). On the other hand, the sixth and fourth valve parts (32
), (, 33), each connection port (9), (9) opening to each valve chamber (10), (10) is connected to the tank line (T).
and pressure balance chambers (15), (15) provided corresponding to these valve parts (32), (36).
is connected to the tank line (T).

Furthermore, the other connection ports (12), (12) of the first and sixth valve parts (30), C62) are connected to one of the shilling lines (A
), while the other connection ports (12), (12) of the second and fourth valve parts (31), (33) are connected to the other cylinder line CB).

The operation of this embodiment will now be explained.

First, it will be explained that the armature (4) is lancing statically.

The armature (4) has its pressure balance chamber (
15) Pump pressure (P.

), f4S 5 Pressure force in the right direction CP+ y A+
) or act. At the same time, the armature (4) has the same (acting pump pressure) applied to the pressure balance chamber (15) corresponding to the second valve part (61) via the interlocking body (14) corresponding to the second valve part (61). (Pl) causes a pressing force (p, ·Ax) in the left direction in Fig. Since (d,) are equal, they become equal and (PEA, -P, A, ), which cancels each other out.

In addition, each connection port (9), (9) of the sixth and fourth valve parts (, 52), (, 53) and each pressure balance chamber (15), (
15') are all connected to the tank line (T), so even if there is back pressure in the tank line (T),
Similarly to the above, each interlocking body (14) of the 6° 4th valve part (32), (33).

(14), the pressing force due to the fluid pressure acting on the armature (4) also cancels each other out.

Therefore, said amateur (4)
The pressing force due to the fluid pressure acting on each other cancels each other out and has almost no effect, so the pressure is statically balanced.

Next, a current is applied to the coil (7) of the torque motor (6) in the direction of the arrow (a) in FIG.
) will be explained clockwise. Since the armature (4) is statically balanced as described above, the force that tries to suppress the clockwise swinging of the armature (4) is applied to the first and fourth valve portions (30), (33)
These are the pressing force of the return springs (18) and (18) and Bernoulli's fluid force. Therefore, the armature (4) is easily swung in a circular motion by the output of the dorsal armature (6) opposing the springs (18), (18) and the fluid force. 4 valve parts (30), (33
) can be opened. At this time, the 2.6th valve part (31), (3
The seat-type valves (8), (8) of 2) are closed by the pressing force of the return springs (, 18), (18).

Therefore, the pump line CP) and cylinder line (A) communicate with each other, while the tank line (T) and cylinder line CB) communicate with each other.

Moreover, by energizing the coil (7) in the opposite direction,
By the same operation, the pump line (P) and the cylinder line (E) can be communicated with each other, and the tank line (T) and the cylinder line (A) can be communicated with each other.

Further, when the coil (7) is de-energized, the second, sixth or first, fourth valve portions (31
), (32) or (30), ([3) seated valve (8) is pushed back to the closed position and at the same time said armature (4) is pushed back to the closed position.
), each interlocking body (14), (14
) and returns to the neutral position.

As mentioned above, the four main valves (60) are attached to the torque motor (6).
- (66) can be combined to achieve control in 6 positions and 4 directions. As mentioned above, since the seat type valve (8) is used, each connection port (9), (1
2) There is almost no leakage between the valves (and the seat type valve (
8)...17) Since the switching operation can be performed with a small sliding stroke, responsiveness is also improved. Furthermore, since the hydraulic pressure acting on the armature (4) is statically balanced, the valve (8) can be switched with a relatively small output of the torque motor (6).

Furthermore, the force acting on the armature (4), that is, the magnetic force by the permanent magnet and each return spring (18)...
Since the pressing forces of the pivot pins (5) act point-symmetrically on the pivot pins (5), almost no force acts on the pivot pins (5), and as a result, the pivot pins (5)
The effect of 5) of good durability can also be obtained.

Moreover, what is shown in FIGS. 7 and 8 is a fourth embodiment of the present invention, in which the pump line (P) and cylinder line (A) in the sixth embodiment, and the tank line (T) and cylinder line CB) are respectively replaced and connected to constitute the same 6-position 4-way valve. (The numbers indicated are the same as those in the sixth embodiment. 7th
It is a symbol diagram of the fourth example shown in the figure. ) Also, the 9th
As shown in FIG. ) may be combined to form an electromagnetic pilot switching valve that controls the 6th position M4 direction. (In FIG. 9, the numbers indicated are the same as those explained in the second and fourth embodiments. Also, FIG. 10 is a symbol diagram of the embodiment shown in FIG. 9.) This fifth embodiment An example will be explained based on Figures 9 and 10.
Just as in the fourth embodiment, a torque motor (6) is installed inside the housing (1), and four first to fourth valve parts (60) to (66) each having a seat type valve (8) are provided. These valve parts (60) to (66) are combined with four seat-type main valves (65) to (68).

For details, see the square main port (
26) to the cylinder line (A), and the side main port (
24) to the pump line CP), and connect the tank line (T) to the square main port (26) of the second seat type main valve (66).
) and the cylinder line (A) is connected to the side main port (24).

Furthermore, the square main port (23) of the sixth seat type main valve (67)
) to the other cylinder line (B), and the side main port)
(24), connect the pump line (P) to the square main port (23) of the fourth seat type main valve (38), and connect the tank line (L) to the side main port 1-(24). The other cylinder line (B) is connected.

In this way, the first and fourth seat type main valves (65) and (38
) is opened, and the second and sixth seat type main valves (36),
(37) closes, the cylinder line (A
) and the pump line (P) are also the cylinder line (B).
and the tank line (T) are in communication with each other, and conversely, the first,
By operating the 4-seat main valves (35) and (38) Rikitsuki MJ and opening the 2.6-seat main valves (36) and (37), the cylinder line (A) and the tank are connected. The line (l), the cylinder line CB, and the pump line (P) are configured to communicate with each other.

Each control circuit for controlling the operation of each of the seat type main valves (65) to (68) is constructed as follows.

That is, it branches from the pump line CP), and the Oriswiss (2
7) is connected to the connection port (12) on the connection chamber (13) side of the first valve part (60),
The other connection port (9) on the valve chamber (10) side of the valve part (filter 0) is connected to the cylinder line (A) to form a first control circuit (28a). The outlet side of the orifice (27) is connected to the first seat type main valve (65).
) to the rear pilot port (25).

Further, a branch passage branching from the cylinder line (A) and having an orifice (69) interposed therein is connected to the connection port (9) on the valve chamber (10) side of the second valve part (61), and the other A second control circuit (4Qa) is formed by connecting the connection port (12) of the circuit (40) to the drain line (nr).
The outlet side of the orifice (39) in a) is connected to the rear pilot port (25) of the second seat type main valve (66).

Similarly, the pump line (P) and the connection port (12) of the sixth valve part (62) are connected via the orifice (27), and the connection port (9) is connected to the cylinder line (B). , a sixth control circuit (28b) is formed, and the sixth control circuit (28b) is formed.
28, b) on the outlet side of the orifice (27).
Rear pilot port of seat type main valve (37) (25)
It connects.

Similarly, the cylinder line (B) and the connection port (9) of the fourth valve part (63) are connected via the orifice (69), and the connection port (12) is connected to the drain line (Dr
) to form a fourth control circuit (40b), and a rear pilot port (2) of the fourth seat type main valve (68) is connected to the orifice (69) outlet side of the circuit (401)).
5).

In addition, in order to balance the static pressure of the hydraulic pressure acting on A7A (4) of the torque motor (6), the first and second valve parts (
30) and (31), respectively, the pressure-cutting lance chambers (15) and (1
5) are communicated with each other, and the first and second valve portions (
30), (31) are communicated with the valve chambers (10), (10), and similarly the pressure balance chambers (15), (15) of the sixth and fourth valve parts (32), (33) are communicated with each other. The valve chambers (1) of the sixth and fourth valve parts (32) and (33) are communicated with each other.
0) and (10).

The operation of this embodiment configured as described above will be explained.

When the coil (7) of the torque motor (6) is energized and the armature (4) is swung clockwise in FIG. 9, the seats of the first and fourth valve parts (6o) and (33) The valves (8) and (8) are opened, and the 1.4 control circuit (
28a) and (40b), so that each of the circuits (28a) and (40b) has t! J Fis (2
7), (69) The pressure on the outlet side decreases, and as a result, the first and fourth seat type main valves (35) and (58) open, while the second and third valve portions (sl) , (62) seat valves (8), (8) remain in the closed position;
Hydraulic oil does not flow into the 6 control circuits (28b) and (40&), so the 2nd and 6th seat type main valves (36) and (37)
is an opening operation. As a result, pump line CP)
and cylinder line (A), and tank line (T)
The cylinder line CB) and the pilot line are connected in advance.

The static pressure balance of the armature (4) at this time will be explained.

First, the first and second valve parts (30) are attached to the armature (4),
Pay attention to the two pressing forces acting through the interlocking bodies (14) and (14) on the (31) side.

Since hydraulic oil does not flow into the second control circuit (40a), the valve chamber (10) of the first valve part (60) and each pressure rosette 7 of the first and second valve parts (60) and (31) room c i5), (
15) shows the fluid pressure (PA) of the same cylinder line (A).
) comes into play. Therefore, the first valve part (60)
The pressing force (PA ・A+ ) due to the fluid pressure (PA) acting on the back surface of the seat-type valve (8) is
) is applied to the moving body (14) on the second valve portion (61) side in the right direction in FIG. 9 through the interlocking body (14). 9th due to the fluid pressure (to P) of the pressure balance chamber (15) acting on the back surface
This is canceled out by the pressing force (FA ・Ax ) in the left direction in the figure. (Incidentally, as in the sixth embodiment, go to A1-) Similarly, the sixth and fourth valve portions (32) are attached to the armature (4).
, (33) side, the two pressing forces that act in opposing manner through the respective moving bodies (14), (14) are also applied to the fourth valve portion (66).
The valve chamber (10) and the pressure balance chambers (15), (15) on the 6°4 valve portions (32), (33) communicate with each other and the same fluid pressure acts on them, so the size is are equal, therefore
Their pressing forces also cancel each other out.

As described above, since the respective suppressing forces acting on the armature (4) cancel each other out, the armature (4) is statically balanced.

Also, by energizing the coil (7) of the torque motor (6) in the opposite direction to the above case, the armature (4)
When the cylinder is swung counterclockwise, the pump line CP) and the cylinder line (B) can be brought into communication, and the tank line (j) and the cylinder line (A) can be brought into communication.

In this case as well, the armature (4) is statically balanced as described above.

Moreover, when the power supply to the coil (7) is cut off, the armature (4) is connected to the permanent magnet (6) and the first and fourth
, 6 valve parts (30), (33) or (31), (32)
Due to the action of the return spring (18), the seat valve (8) returns to the neutral position and the seat valve (8), which had been open, is also closed. As a result, all flow of hydraulic oil between the lines is blocked.

In addition, when the pressure of the pump line (P) is higher than the pressure of the pair of cylinder lines (A) and (B) when the power is not energized, the first
．． Sixth seat type main valve (35).

(67) is closed, and when the pressure in the pump line (p) is lower than the pressure in the pair of cylinder lines (A) and (B), the check valve (50) in the pump line (P) is closed, and the entire Functions similar to port blocking.

As described above, each of the seat-type valves (8) is made to function as a pilot valve, and these valves (8) are combined with the four seat-type main valves (65) to (68). The sliding stroke of the opening/closing operation of (8) can be made small, and therefore the responsiveness of the switching operation of each line can be made good.
), the seat-type main valves (65) to (68) hardly cause any leakage, so no leakage occurs between the lines.

Furthermore, since the armature (4) is statically balanced, each line can be switched with a relatively small output from the torque motor (6).

Therefore, this switching valve connects the coil (7) of the torque motor (6) to a pulse width converter W/J and repeats the switching operation in a very short cycle using a single pulse signal to control the flow of each line. It is extremely suitable for controlling.

In particular, since the pilot flow precedes the main valve flow, it is possible to obtain PWM control that is favorable for control and has excellent responsiveness, durability, high frequency operation, and load holding capacity. ), a permanent magnet (6) and a pivot pin (5) disposed within the magnetic field of the permanent magnet (6).
A torque motor (6) having an armature (4) and a coil (7) which are swingably supported by the housing (1) is provided with a torque motor (6) that is swingably supported by the armature (4) and a valve chamber (8) in which the seat-type valve (8) is housed. 10) and a valve part (60) having a valve hole (11) that is opened and closed by the seat-type valve (8), and connection ports (9) and (12) that open before and after the valve hole (11). On the other hand, an interlocking body () is provided between the − side of the swinging direction of the armature (4) and the seat-type valve (8) to enable the seat-type valve (8) to be operated by the operation of the armature (4). 14
), and a cover chamber (1) communicating with the valve chamber (10) is provided on the rocking force side of the armature (4).
Since the balance piston (17) facing 5) was provided,
Said connection port 1-(9).

(12) to minimize leakage between the valves (8) and
The sliding stroke caused by the opening/closing operation can be reduced, and therefore the responsiveness of the opening/closing operation can be improved, and furthermore, the opening/closing operation can be performed with a relatively small output of the torque motor (6).

[Brief explanation of the drawing]

Fig. 1 shows a first embodiment of the present invention, and is an explanatory diagram with main parts in cross section, Fig. 2 is a symbol diagram of the first embodiment, and Fig. 6 shows a second embodiment of the invention. Fig. 4 is a symbol diagram thereof, and Fig. 5 is an explanatory drawing showing a sixth embodiment of the present invention, with the main part shown in cross section. FIG. 6 is a symbol diagram thereof, and FIG. 7 is an explanatory diagram showing a fourth embodiment of the present invention, with main parts in cross section.
Fig. 8 is a symbol diagram thereof, Fig. 9 is an explanatory diagram showing a fifth embodiment of the present invention, with main parts in cross section, Fig. 110 is a symbol diagram thereof, and Fig. 11 is an explanatory diagram showing a conventional example. It is a diagram. (1)...Housing (6)...Permanent magnet (4)...Amateur (5)...Pivot bottle (6)...Torque motor (7)...Coil (8) ...Seat type valves (9), (12)...Connection boat (10)...Valve chamber (14)...Moving body (15)...Balance piston (60) to (66)...・Valve part

Claims (1)

[Claims] (1) in the housing (1) a permanent magnet (6) and a pivot pin (5) disposed within the magnetic field of the permanent magnet (6);
A torque motor (6) having an armature (4) and a coil (7) which are swingably supported by the housing (1) is provided with a torque motor (6) that is swingably supported by the armature (4) and a valve chamber (8) in which the seat-type valve (8) is housed. 1°0), a valve hole (11) that is opened and closed by the seat-type valve (8), and a Gf40 valve hole (11) before and after the valve hole (11).
a valve part (60) having connection boats (9), (12) to
On the other hand, the armature (
An interlocking body (14) is provided which enables the seat-type valve (8) to be operated by the actuation of step 4), and a pressure balance communicating with the valve chamber (10) is provided on the other side in the swinging direction of the armature (4). A solenoid valve characterized by being provided with a balance piston (17) facing a chamber (15).