JPH0718442B2 - Solenoid pilot switching valve - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electromagnetic pilot switching valve that performs switching using a solenoid-driven pilot spool.

(Prior Art) Conventionally, this kind of switching valve is disclosed in, for example, Japanese Utility Model Laid-Open No. 54-56092, and as shown in FIG. 10, a pair of switching ports (A , B) One side is switched to the pump port (P) and the other side is switched to the tank port (T1, T2) Main valve spool (S) and solenoid (D) operated according to the electric command input are additionally moved. And a pilot spool (R) for controlling the main valve spool (S) by the operation of the pilot spool (R).

That is, when the pilot spool (R) is at the position shown in the drawing, each pilot passage (L, K) is in communication with the tank (T3, T4), and the main valve spool (S) has both working chambers (X,
It is held in a neutral position by an offset spring (M, N) arranged in Y), and both switching ports (A, B) are blocked with respect to pump port (P) and tank port (T1, T2), When the pilot spool (R) is moved to the left by the operation of the solenoid (D) and the left pilot passage (L) is communicated with the pressure line (G) extending from the pump port (P) via the land (E), Pilot pressure is introduced into the left action chamber (X) to move the main valve spool (S) to the right, the left switching port (A) to the pump port (P) and the right switching port (B) to It is connected to each tank port (T2). Conversely, when the pilot spool (R) is moved to the right, pilot pressure is introduced into the right working chamber (Y) via the pressure line (G), the land (F) and the right pilot passage (K). The right switching port (B) communicates with the pump port (P) and the left switching port (A) communicates with the tank port (T1).

(Problems to be Solved by the Invention) With the above configuration, the switching port (A, B) can be reversibly switched between the pump port (P) and the tank port (T1, T2). Two pilot passages (L) (K) are installed on the pilot spool (R) because the pilot pressure is introduced and the tanks (T3, T4) are opened selectively. Two lands (E) and (F) are required to control the opening and closing of the passages (L) and (K), and each pilot passage (L) is required for these two lands (E) and (F).
The physical layout of (K) needs to be set individually, which complicates the porting design, and when the pressure in the pressure line (G) fluctuates, the pilot pressure also fluctuates. There is also a problem that the operation of the valve spool (S) becomes unstable and the opening degree of the switching ports (A) and (B) cannot be adjusted more accurately.

The object of the present invention is to enable reversible switching of the main valve spool by simply controlling the working fluid in only one working chamber on one side of the main valve spool, and to relax the port design of the pilot spool portion. In addition, it is an object of the present invention to provide an electromagnetic pilot switching valve capable of performing balanced operation of the main valve spool in both directions, and further capable of stable operation of the main valve spool.

(Means for Solving the Problems) In order to achieve the above object, the invention according to claim 1 is such that one side of the pair of switching ports (A) and (B) is a pump port (P) and the other side is a tank. Main valve spool (1) for switching to ports (T1) and (T2), pilot spool (2) having solenoid (5) that operates according to input of an electric command position, and driver for driving the solenoid (5) (6) and an electromagnetic pilot switching valve which switches the main valve spool (1) by the operation of the pilot spool (2), the first pilot valve being provided on one side of the main valve spool (1). When the pilot spool (2) is moved to the working chamber (3), the throttle control unit (91) is operated.
A second working chamber provided on the other side of the main valve spool (1) by connecting a pilot passage (9) that reversibly communicates with the pressure supply line (7) and the tank line (8) via the (92). The pressure supply line (7) is connected to (4), and the second pressure receiving surface (40) of the second working chamber (4) is connected to the first pressure receiving surface (30) of the first working chamber (3). The main valve position detector (17) for detecting the position of the main valve spool (1), the position signal from the main valve position detector (17) and the position of the pilot spool (2) are commanded. A driver (6) that outputs a control signal to the solenoid (5) and a pressure sensor (110) that detects the pressure of the pressure supply line (7). The driver (6) includes the pressure sensor (11).
The compensating circuit (120) is provided to correct the control signal output to the solenoid (5) based on the pressure signal from (0).

Further, in the invention of claim 2, in the invention of claim 1, the pressure of the pressure supply line (7) is detected, whereas the pilot pressure sensor (111) for detecting the pressure of the first working chamber (3). ) And the driver (6),
A compensation circuit (130) is provided to correct the control signal output to the solenoid (5) based on the pressure signal from the pressure sensor (111).

In the invention according to claims 1 and 2, in order to balance the operations of the main valve spool (1) in both directions, the second valve
The area ratio between the pressure receiving surface (40) and the first pressure receiving surface (30) is preferably set to 1: 2.

(Operation) In the invention according to claim 1, when the pilot passage (9) communicates with the pressure line (7) through the throttle control section (91) by the movement of the pilot spool (2), the first operation chamber A pressing force commensurate with the area acts on the first pressure receiving surface (30) of (3). On the other hand, the second working chamber (4) is always communicated with the pressure line (7), but since the second pressure receiving surface (40) is smaller than the first pressure receiving surface (30), the second working chamber (4) is The pressing force from the 4) side is smaller than that from the first working chamber (3) side. Therefore, the main valve spool (1) is moved to one side by the pressing force from the first working chamber (3) side. On the contrary, the movement of the pilot spool (2) causes the diaphragm control unit (9
When the pilot passage (7) is connected to the tank line (8) side via 2), the main valve spool (1) is moved to the other side by the pressing force from the second working chamber (4) side. Will be. In this way, one of the switching ports (A) and (B) is reversibly switched to the pump port (P) and the other to the tank port (T1, T2) simply by controlling the opening / closing of one pilot passage (9). It becomes possible.

Then, the movement control of the pilot spool (2) is basically performed by a calculation unit (61) using a position signal fed back from the main valve position detector (17) and a command signal for commanding the position of the pilot spool (2). ), A driver (6) outputs a control signal based on the result of the calculation to drive the solenoid (5) for control. In addition to this, the pressure supply line Since the control signal is corrected based on the pressure signal from the pressure sensor (110) for detecting the pressure of (7), even when pressure fluctuation occurs on the pressure supply line (7) side, The pressure fluctuation is detected by the pressure sensor (110), the control signal output to the solenoid (5) is corrected by the compensation circuit (120) based on the detected value, and the corrected control signal is corrected by the solenoid. The pilot spool (2) is output by being output to the noid (5) side, and as a result, even if the supply pressure to the pilot spool (2) fluctuates in the main valve spool (1). , Stable operation without being affected by this pressure fluctuation,
The controllability can be improved.

In the invention according to claim 2, the control signal is corrected based on the pressure signal from the pilot pressure sensor (111) that detects the pressure in the first working chamber (3). Even if a pressure fluctuation occurs on the first working chamber (3) side, the pressure fluctuation is caused by the pilot pressure sensor (111).
The pressure change output unit (112) calculates the pressure fluctuation of the first working chamber (3) as a temporal pressure change based on the detected value, and the correction control signal based on the calculated value is calculated. Since it is output from the compensation circuit (130) to the solenoid (5) side, a high damping effect is exhibited without causing hunting or the like on the main valve spool (1) side due to a minor loop of pressure change. As a result, more stable control of the main valve spool (1) is performed, and the controllability of the positioning system can be further improved.

Further, in the invention according to claim 3, since the area ratio of the first pressure receiving surface (30) and the second pressure receiving surface (40) is set to 1: 2, the pressure line ( The degree of increase in pressure when introducing the working fluid from 7) and the degree of decrease in pressure when releasing the working fluid from the first working chamber (3) to the tank line (8) are equalized. The bidirectional movement of (1) can be balanced.

(Embodiment) FIG. 1 shows an embodiment of an electromagnetic pilot switching valve according to the invention described in claim 1, which is a main valve portion (100) provided with a main valve spool (1) and a pilot valve. A pilot valve part (200) having a spool (2), the main valve spool (1) is installed in a spool hole (11) formed in a valve box (10), and two lands (12) ( 13), one side of the pair of switching ports (A) and (B) is switched to the pump port (P) and the other side is switched to the tank port (T1 or T2). The pump port (P) is
Connected to the discharge line (PH) of the hydraulic pump (PM),
The switching ports (A) and (B) are respectively connected to the rod chamber (W1) and the head chamber (W2) of the actuator (W). In addition, each tank port (T1) (T2) has a passage (80)
Are communicated with each other through and are opened to the tank (T).

Further, a first working chamber (3) for pressing the spool (1) to the right side in the drawing is provided at one end side (left side in the drawing) of the main valve spool (1), and the other end side ( A differential piston (15) guided by a sleeve (14) is arranged on the right side in the figure, and the main valve spool (1) is pressed leftward on the back side of the piston (15). A second working chamber (4) is provided. A main valve position detector (17) for detecting the position of the main valve spool (1) using the differential piston (15) is provided at the other end of the main valve spool (1). In the example,
As the main valve position detector (17), a differential transformer (17) consisting of a detection iron core (17a) and a detection coil (17b) is used, and the detection iron core (17a) is inserted through a rod (16). The detection coil (17b) is connected to a differential piston (15), and the movement of the detection iron core (17a) accompanying the piston (15) is detected.
It is possible to detect the operating position of the main valve spool (1) by detecting. The main valve position detector (17) is not limited to the differential transformer (17), but may be a potentiometer or the like.

The pilot spool (2) is for operating the main valve spool (1) and is a small valve box (2).
0) is provided in a spool hole (21), an offset spring (22) is provided at one end, and the movable iron core (5) of a solenoid (5) is provided at the other end via an operating rod (23).
It is combined with 1).

A position signal (f) fed back from the detection coil (17b) constituting the main valve position detector (17) between the solenoid (5) and the main valve position detector (17).
And a calculation unit (61) for comparing and calculating a command signal (d) for commanding the position of the pilot spool (2), and an amplifier (62) for increasing the output of the signal calculated by the calculation unit (61). A driver (6) consisting of the driver (6) is arranged, and the movable iron core (51) of the solenoid (5) is displaced by a control signal from the amplifier (62) of the driver (6), and the pilot spool (2) Are trying to control.

Then, in the pressure chamber (26) defined by the pair of left and right lands (24) (25) provided on the pilot spool (2),
The pressure line (7) extending from the pump port (P) is opened, and the spring chamber (27) in which the offset spring (22) is arranged is opened to the tank line (8) leading to the tank (T). , These pressure chamber (26) and spring chamber (2
7) The land (24) for partitioning the
The connection port (90) of the pilot passage (9) leading to the working chamber (3) is made to face the land (2) in a substantially zero-lap state.
4) Aperture control part (91) formed on both edge parts
The pressure line (7) and the tank line (8) are reversibly communicated with the pilot passage (9) through the (92).

Further, the pressure line (7) is connected to the second working chamber (4) via a pressure chamber (26) and a connection port (28) and a connection line (29) opened in the pressure chamber (26). To do. In this case, the connection port (28) does not depend on the position of the land (25), that is, the pilot spool (2).
Is always open to the pressure chamber (26) regardless of the position.

Thus, one of the pressure line (7) and the tank line (8) is connected to the first working chamber (3),
The pressure line (7) is always connected to the working chamber (4). Further, because of the connection relationship between them, the main valve spool (1) can be moved both rightward and leftward, so that the second pressure receiving surface (in the differential piston (15) facing the second action chamber (4) ( The area of 40) is smaller than that of the first pressure receiving surface (30) corresponding to the area of the end land (18) of the main valve spool (1) facing the first working chamber (3).

Then, the command signal (d) for commanding the position of the pilot spool (2) is input, and the driver (6)
When the pilot spool (2) is moved leftward in FIG. 1 via the solenoid (5) and the solenoid (5), the pilot passage (9) passes through the throttle control section (91) and the pressure line (7). The first working chamber (3) is opened to the pressure line (7), and a pressing force commensurate with the area acts on the first pressure receiving surface (30). On the other hand, the second working chamber (4) is always open to the pressure line (7) side, but the second pressure receiving surface (40) is smaller than the first pressure receiving surface (30),
The pressing force from the second working chamber (4) side is the first working chamber (3).
Smaller than that on the side. Therefore, the first working chamber (3)
The pressure from the side exceeds the pressure from the second working chamber (4) side, the main valve spool (1) is moved to the right, and the switching port (B) is moved to the pump port (P). , The switching port (A) communicates with the tank port (T1), and the actuator (W) is moved in the advancing direction.

Further, the rightward movement of the main valve spool (1) is detected by the main valve position detector (17), and the position signal (f) and the command signal (d) by the detector (17) are sequentially detected. Since the difference becomes small, the current value to the solenoid (5) is limited, the movement amount of the pilot spool (2) is adjusted, the opening area of the aperture control section (91) is reduced, and the command signal (d ) And the position signal (f) coincide with each other, and after reaching the target position, the diaphragm control section (91) is closed.

Next, when the pilot spool (2) is moved to the right in the drawing by another command signal (d), the pilot passage (7) goes to the tank line (8) via the throttle control section (92). In communication, the first working chamber (3) is opened to the tank (T), and the main valve spool (1) is moved leftward in the figure by the pressing force from the second working chamber (4) side. , The switching port (A) is connected to the pump port (P) and the switching port (B) is connected to the tank port (T2),
The actuator (W) will be retracted.

The series of switching operations described above can be performed only by controlling the opening / closing of one pilot passage (9) by the pilot spool (2). Therefore, the opening / closing control of the pilot passage (9) and the passage (9) is performed. All that is required is to determine the positional relationship with only one land (24), which simplifies the porting design.

Furthermore, the embodiment shown in FIG. 1 has the valve box (1) of the main valve portion (100) of the electromagnetic pilot switching valve configured as described above.
A pressure sensor (110) for detecting the pressure of the pressure supply line (7) is provided on the above (0), and the main valve position detector (17) feeds back to the driver (6). Position signal (f) of valve spool (1)
And a command section (61) for comparing and calculating the command signal (d) of the pilot spool (2), the calculated value by the calculator (61) is converted into a pressure signal from the pressure sensor (110). By providing the compensating circuit (120) which is corrected based on the above, and is output as the control signal (s) on the solenoid (5) side, the influence on the change of the supply pressure to the pilot spool (2) can be reduced and the main valve spool The controllability of the positioning system of (1) can be improved.

Specifically, as is clear from the block diagram of FIG. 2, the pressure supply line (7) is connected to the pilot spool (2).
To the pilot spool supply pressure (P
A pressure sensor (110) for detecting p) is provided, and a compensating circuit (120) is provided on the output side of the pressure sensor (110) through a compensation value switching comparator (121). A position signal (f) of the main valve spool (1) fed back from (17) and a command signal (d) of the pilot spool (2) are compared by a calculation unit (61) of the driver (6). The calculated value is input to the compensation circuit (120), and the calculated value calculated by the calculation section (61) in the compensation circuit (120) is corrected based on the pressure detection value from the pressure sensor (110). This correction signal is output as a control signal (s) to the pilot spool (2) side via the voltage / current converter (122).

In the case of the above configuration, even if a pressure fluctuation occurs on the pressure supply line (7) side due to a change in the introduction pressure from the pump port (P), the pressure fluctuation is detected by the pressure sensor (110). The control signal (s) output to the solenoid (5) based on the detected pressure value.
Is corrected by the compensation circuit (120), and the solenoid (5) is controlled by the corrected control signal (s), so that the main valve spool (1) moves to the pilot spool (2). As a result, stable control can be performed without being affected by changes in the supply pressure, and as a result, the controllability of the main valve spool (1) can be improved.

Furthermore, FIG. 3 shows a second embodiment of the invention according to claim 1, in which the pressure sensor (110) is arranged on the valve box (10) of the main valve portion (100). , The movable iron core (51) of the solenoid (5) is connected to the detection iron core (54a) of the sub differential transformer (54) via the detection rod (53), and the driver () is connected via the detection coil (54b). The moving position (mf) of the pilot spool (2) is fed back to the driver 6) while the driver (6) has two first and second calculators (61a) (61a) (61a) as the calculator (61).
b) is provided respectively, and the position signal (f) fed back from the main valve position detector (17) in the first arithmetic unit (61a) is compared with the command signal (d) of the pilot spool (2). In addition, in the second calculation unit (61b), the calculation unit calculated in the first calculation unit (61a) and the moving position (mf) fed back from the pilot spool (2) are compared and calculated. The pressure sensor (11a) (61b) calculates the calculated value by the pressure sensor (11
Compensation circuit (12) that corrects based on the pressure signal from (0) and outputs as a control signal (s) to the solenoid (5) side.
0) is provided.

Specifically, as is apparent from the block diagram of FIG. 4, the pressure supply line (7) is connected to the pilot spool (2).
To the pilot spool supply pressure (P
p) is provided with a pressure sensor (110), and two first and second compensation circuits (120a) (120a) (120a) are provided on the output side of the pressure sensor (110) via a compensation value switching comparator (121). 120b) is provided, and the position signal (f) of the main valve spool (1) fed back from the main valve position detector (17) and the command signal (d) of the pilot spool (2) are supplied to the first The calculation unit (61a) performs comparison calculation,
Input to the first compensation circuit (120a), and the compensation circuit (12a
In 0a), the calculation value by the first calculation unit (61a) is corrected based on the pressure detection value from the pressure sensor (110), and the correction value by the first compensation circuit (120a) and the sub differential The position signal (mf) of the pilot spool (2) fed back from the transformer (54) is compared and calculated by the second calculation unit (61b), and the second compensation circuit (1
20b), and the compensation value by the first compensation circuit (120a) is input by the compensation circuit (120b) to the pressure sensor (110).
The correction signal is re-corrected on the basis of the detected pressure value, and the correction signal is output as a control signal (s) to the pilot spool (2) side via the voltage / current converter (122).

With the above configuration, when a pressure fluctuation occurs on the pressure supply line (7) side due to a change in the introduced pressure from the pump port (P), the pressure fluctuation is detected by the pressure sensor (110). The control signal (s) output to the solenoid (5) is double corrected by the two compensation circuits (120a) (120b) based on the pressure detection value, and the corrected control signal (s) is corrected. Is output to the solenoid (5) side, so that the controllability of the main valve spool (1) can be further improved.

When controlling the solenoid (5), that is, the pilot spool (2) by the compensation circuit (120),
As shown in FIG. 5, a plurality of comparison / determination circuits are used, and in each of these determination circuits, the pilot spool supply pressure (Pp) and a plurality of set pressures (series pressures sequentially set lower than the supply pressure (Pp) ( The compensation values (Gc1 to Gc0) of the solenoid (5) by the compensation circuit (120) are selectively controlled by comparing P1) to (Pk).

In the embodiment shown in FIGS. 1 and 3, the area ratio between the first pressure receiving surface (30) and the second pressure receiving surface (40) is 1: 2.
It is preferable to set to
Of the rate of pressure increase when the working fluid is introduced into the working chamber (3) from the pressure line (7) and the decrease of the pressure when releasing the working fluid from the first working chamber (3) to the tank line (8). The ratio can be equalized, and the case where the main valve spool (1) is moved to the right and the case where it is moved to the left can be balanced.

Next, a first embodiment of the electromagnetic pilot switching valve according to the invention of claim 2 will be described with reference to FIG.

The first embodiment is the electromagnetic pilot switching valve according to the invention described in claim 1 shown in FIG.
The pressure sensor (110) for detecting the pressure of the pressure supply line (7) is arranged on the valve box (10) of the above, but instead of this, the valve box (10) in the main valve section (100). A pilot pressure sensor (111) for detecting the pressure of the first working chamber (3) is provided on the side of the driver, and the driver (6) is provided with the pilot pressure sensor (111) based on the pressure signal from the pilot pressure sensor (111). A pressure change output unit (112) for calculating and outputting a pressure change in the first working chamber (3) is provided, while the driver (6) has two first and second calculation units as the calculation unit (61). Parts (61c) and (61d) are provided respectively, and the main valve position detector (1
The position signal (f) fed back from 7) is compared with the command signal (d) of the pilot spool (2),
In addition, in the second calculation unit (61d), the first calculation unit (61c)
The calculated value calculated in (1) and the output value from the pressure change output section (112) are compared and calculated, and the first and second calculating sections (61
c) A compensation circuit (130) for correcting the calculated value by (61d) based on the pressure signal from the pilot pressure sensor (111) and outputting it as a control signal (s) to the solenoid (5) side is provided. It is a thing.

Specifically, as is clear from the block diagram of FIG. 7, the position signal (f) of the main valve spool (1) fed back from the main valve position detector (17) and the pilot spool (2) are fed back. First to compare and calculate the command signal (d)
An arithmetic unit (61c) is provided, and a second arithmetic unit (61d) is provided on the output side of the first arithmetic unit (61c).
At the input side of 1d), the pilot pressure sensor (111) arranged in the first working chamber (3) and the pressure change output section (11)
2) are provided respectively, and the pressure change output section (112) calculates the pressure change in the first working chamber (3) based on the pilot pressure sensor (111), and the calculated value and the first calculation section ( The output value from 61c) is compared and calculated by the second calculation unit (61d), while the compensation circuit (130) is provided on the output side of the second calculation unit (61d), and the compensation circuit (61) is provided. 13
In 0), the output value from the second calculation unit (61d) is corrected,
This correction signal is output as a control signal (s) to the pilot spool (2) side via the voltage / current converter (132).

With the above configuration, when a pressure fluctuation occurs on the side of the first working chamber (3) due to a change in the introduced pressure from the pump port (P), the pressure fluctuation is generated by the pilot pressure sensor (111). The pressure change output section (112) is detected and the first working chamber (3) is detected based on the detected value.
Is calculated as a change in pressure over time, and the values calculated by the two calculation units (61c) (61d) are corrected by the compensation circuit (130), and the compensation time is calculated by the compensation circuit (13).
The correction control signal (s) from the compensation circuit (130) is output to the solenoid (5) side, and in other words, it constitutes a minor loop of pressure change. Therefore, a high damping effect is exhibited without causing hunting on the main valve spool (1) side, and more stable control of the main valve spool (1) can be performed without being affected by changes in pilot pressure. The controllability of the positioning system for the main valve spool (1) can be further improved.

Furthermore, FIG. 8 shows a second embodiment of the electromagnetic pilot switching valve according to claim 2, wherein the first working chamber (on the side of the valve box (10) in the main valve portion (100) is The pilot pressure sensor (111) for detecting the pressure of 3) is arranged, and the pressure in the first working chamber (3) is provided to the driver (6) based on the pressure signal from the pilot pressure sensor (111). A pressure change output section (112) for calculating and outputting a change is provided, and the movable iron core (51) of the solenoid (5) has a detection rod (53) as in the case of FIG.
The detection iron core (54a) of the sub-differential transformer (54) is coupled through the feedback coil (54b), and the moving position (mf) of the pilot spool (2) is fed back to the driver (6) side. On the other hand, the driver (6) is provided with three first to third arithmetic units (61e) (61f) (61g) as the arithmetic unit (61), and the first arithmetic unit (61e) The position signal (f) fed back from the main valve position detector (17) and the command signal (d) of the pilot spool (2) are compared and calculated, and
In the second calculation unit (61f), the first calculation unit (61f
The calculated value calculated in e) and the pressure change output section (112)
A pressure change value output from the pilot spool (2) is fed back from the pilot spool (2), and the calculated value calculated by the second calculation section (61f) in the third calculation section (61g). The moving position (mf) of the pilot pressure sensor (111) is calculated based on the pressure signal from the pilot pressure sensor (111), and the calculated values by the first to third calculation units (61e) (61f) (61g) are corrected. A compensation circuit (130) for outputting a control signal (s) is provided on the solenoid (5) side.

Specifically, as is clear from the block diagram of FIG. 9, the position signal (f) of the main valve spool (1) fed back from the main valve position detector (17) and the pilot spool (2) A first calculation unit (61e) for comparing and calculating the command signal (d) is provided, and a second calculation unit (61f) and a third calculation unit (61g) are provided on the output side of the first calculation unit (61e). At the same time, on the input side of the second operation unit (61f), the first
A pilot pressure sensor (11
1) and the pressure change output section (112) are provided, and the pilot pressure sensor (11
Based on 1), the pressure change of the first working chamber (3) is calculated, and the output value from the operation unit and the first operation unit (61e) is compared and calculated by the second operation unit (61f). None, and the output value from the second computing unit (61f) and the position signal (mf) of the pilot spool (2) fed back from the sub differential transformer (54) are set to the third computing unit (61g). While the comparison calculation is performed with, the third calculation unit (61g)
The compensating circuit (130) is provided on the output side of the compensating circuit, and the compensating circuit (130) compensates the output value from the third computing unit (61g) to output the compensation signal to the voltage / current converter (132). The control signal (e) is output to the pilot spool (2) side via the above.

With the above configuration, when a pressure fluctuation occurs on the side of the first working chamber (3) due to a change in the introduced pressure from the pump port (P), the pressure fluctuation is generated by the pilot pressure sensor (111). The pressure change output section (112) is detected and the first working chamber (3) is detected based on the detected value.
Pressure fluctuations are calculated as changes over time, and the values calculated by the three calculation units (61e) (61f) (61g) are corrected by the compensation circuit (130), and the corrected control signals are calculated. Since (s) is output to the solenoid (5) side, high-performance control of the main valve spool (1) is possible while stable control of the main valve spool (1) is performed. Of.

Further, also in the embodiments shown in FIGS. 6 and 8, the area ratio between the first pressure receiving surface (30) and the second pressure receiving surface (40) is 1 :.
It is preferable to set it to 2. In such a case, the rate of pressure increase when the working fluid is introduced into the first working chamber (3) from the pressure line (7) and the tank from the first working chamber (3). The rate of pressure drop when releasing the working fluid to the line (8) can be equalized, and the case of moving the main valve spool (1) to the right and the case of moving to the left can be balanced. is there.

The above-mentioned compensation circuit and compensation value switching comparator are not limited to the analog type, but a digital type constituted by a CPU can be adopted.

(Effect of the invention) According to the invention of claim 1, the main spool (1) can be moved in both directions only by controlling the opening and closing of one pilot passage (9) by the pilot spool (2). It suffices to provide only one pilot passage (9) and one land for controlling the opening and closing of the pilot passage, and since it is sufficient to determine the positional relationship of these one place, the porting design can be simplified accordingly. It is possible to reversibly switch one of the switching ports (A) and (B) to the tank port (P) and the other to the tank port (T1, T2).

Then, the position signal fed back from the main valve position detector (17) and the command signal for commanding the position of the pilot spool (2) are compared and calculated by the calculation unit (61), and the driver is based on this calculation result. (6) outputs a control signal to drive the solenoid (5) to control the pilot spool (2). In addition to this, the pressure for detecting the pressure in the pressure supply line (7) is detected. Since the control signal is corrected based on the pressure signal from the sensor (110), even if a pressure fluctuation occurs on the pressure supply line (7) side, the pressure fluctuation is generated by the pressure sensor (110). The control signal detected and output to the solenoid (5) based on the detected value is corrected by the compensation circuit (120), and the corrected control signal is output to the solenoid (5) side. Before Storage valve spool (1)
Even if the supply pressure to the pilot spool (2) fluctuates, stable control can be performed without being affected by this pressure fluctuation, and as a result, its controllability can be improved.

In the invention according to claim 2, the first working chamber (3)
The pilot pressure sensor (111) for detecting the pressure of
Since the control signal is corrected based on the pressure signal from the pilot pressure sensor (111), when the pressure fluctuation occurs on the first working chamber (3) side, the pressure fluctuation is caused by the pilot pressure sensor (111).
The pressure change output unit (112) calculates the pressure fluctuation of the first working chamber (3) as a temporal pressure change based on the detected value, and the correction control signal based on the calculated value is calculated. Since it is output from the compensation circuit (130) to the solenoid (5) side, a high damping effect is exhibited without causing hunting or the like on the main valve spool (1) side due to a minor loop of pressure change. As a result, more stable control of the main valve spool (1) is performed, and the controllability of the positioning system can be further improved.

In the invention according to claim 3, the first pressure receiving surface (30) and the second pressure receiving surface (30)
By setting the area ratio with the pressure receiving surface (40) to 1: 2,
The degree of pressure increase when the working fluid is introduced into the first working chamber (3) from the pressure line (7), and the first working chamber (3)
The pressure drop when releasing the working fluid from the tank to the tank line (8) is equalized, and the bidirectional movement of the main valve spool (1) can be balanced.

[Brief description of drawings]

1 is a sectional view showing a first embodiment of an electromagnetic pilot switching valve according to the invention described in claim 1, FIG. 2 is a block diagram of its control system, and FIG. 3 is a sectional view showing the same second embodiment. , 4th
FIG. 5 is a block diagram of the control system, FIG. 5 is a control flowchart, FIG. 6 is a sectional view showing a first embodiment of the electromagnetic pilot switching valve according to the invention of claim 2, and FIG. 7 is its control system. FIG. 8 is a sectional view showing the second embodiment of FIG. 6, FIG. 9 is a block diagram of its control system, and FIG. 10 is a sectional view of a conventional example. (1) …… Main valve spool (2) …… Pilot spool (3) …… First working chamber (30) …… First pressure receiving surface (4) …… Second working chamber (40) …… Second pressure receiving Surface (5) …… Solenoid (6) …… Driver (61) …… Computing unit (7) …… Pressure supply line (70) …… Secondary constant pressure reducing valve (8) …… Tank line (9) …… Pilot passage (17) …… Main valve position detector (110) …… Pressure sensor (111) …… Pilot pressure sensor (112) …… Pressure change output section (120,130) …… Compensation circuit (A) (B) ) …… Switching port (P) …… Pump port (T1) (T2) …… Tank port

Claims (3)

[Claims] 1. A pair of switching ports (A) and (B), one side being a pump port (P) and the other side being a tank port (T1).
A main valve spool (1) that is switched to (T2), a pilot spool (2) having a solenoid (5) that operates according to the input of an electric command position, and a driver (6) that drives the solenoid (5). In the electromagnetic pilot switching valve, which is configured to switch the main valve spool (1) by the operation of the pilot spool (2), a first working chamber (3) provided on one side of the main valve spool (1). ),
By the operation of the pilot spool (2), a pilot passage (9) that reversibly communicates with the pressure supply line (7) and the tank line (8) via the throttle control units (91) (92) is connected. , The pressure supply line (7) is connected to the second working chamber (4) provided on the other side of the main valve spool (1), and the second pressure receiving surface (40) of the second working chamber (4) is A main valve position detector (17) for detecting the position of the main valve spool (1) while making the size smaller than the first pressure receiving surface (30) of the first working chamber (3), and the main valve position detector. A driver (6) for outputting a control signal to the solenoid (5), which has a calculation unit (61) for comparing a position signal from the (17) with a command signal for commanding the position of the pilot spool (2); Pressure sensor (11) that detects the pressure in the supply line (7)
0), and the driver (6) corrects the control signal output to the solenoid (5) based on the pressure signal from the pressure sensor (110).
An electromagnetic pilot switching valve characterized by being equipped with. 2. A pair of switching ports (A) and (B), one side being a pump port (P) and the other side being a tank port (T1).
A main valve spool (1) that is switched to (T2), a pilot spool (2) having a solenoid (5) that operates according to the input of an electric command position, and a driver (6) that drives the solenoid (5). In the electromagnetic pilot switching valve, which is configured to switch the main valve spool (1) by the operation of the pilot spool (2), a first working chamber (3) provided on one side of the main valve spool (1). ),
By the operation of the pilot spool (2), a pilot passage (9) that reversibly communicates with the pressure supply line (7) and the tank line (8) via the throttle control units (91) (92) is connected. , The pressure supply line (7) is connected to the second working chamber (4) provided on the other side of the main valve spool (1), and the second pressure receiving surface (40) of the second working chamber (4) is A main valve position detector (17) for detecting the position of the main valve spool (1) while making the size smaller than the first pressure receiving surface (30) of the first working chamber (3), and the main valve position detector. A driver (6) for outputting a control signal to the solenoid (5), which has a computing unit (61) for comparing the position signal from the (17) with a command signal for commanding the position of the pilot spool (2);
A pilot pressure sensor (111) for detecting the pressure of the working chamber (3), and the driver (6) outputs to the solenoid (5) based on the pressure signal from the pressure sensor (111). Compensation circuit to correct the signal (13
0) An electromagnetic pilot switching valve characterized by being provided with. 3. The electromagnetic pilot switching valve according to claim 1, wherein the area ratio between the second pressure receiving surface (40) and the first pressure receiving surface (30) is set to 1: 2.