JPH01277912A - Proportional solenoid reducing valve and proportional solenoid control valve and its control circuit - Google Patents

Abstract

PURPOSE:To improve operability and safety by providing a proportional solenoid reducing valve which reduces the pressure of supply pressure oil in proportion to increase or reduction of an applied current, a proportional solenoid control valve which has this reducing valve built in to control switching of the outflow direction and the outflow rate, and a control circuit. CONSTITUTION:A proportional electromagnetic coil 3 is used for the operation of a valve spool 4, and the spool 5 is moved in accordance with the applied current to arbitrarily control the discharge quantity of pressure oil from a pressure oil discharge side 11 and the supply quantity of pressure oil to the pressure oil discharge side. A proportional solenoid control valve 30 consists of one direction control valve main body 3 and a pair of proportional solenoid reducing valves 1a and 1b, and the reducing valve 1 sets the pressure of sent pilot oil to a prescribed value by the applied current and not only compresses a return spring 55 to a neutral position for a main spool 33 to move the spool 33 but also stops the spool 33 in the position where the spool and the spring 55 are balanced. Thus, switching of the feeding-out direction of operating oil and the feed-out quantity are arbitrarily controlled. In this case, a dead zone setting circuit 105 of a move position detector 56 is provided to improve the operability and the safety.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a proportional electromagnetic pressure reducing valve that reduces the pressure of supplied pressure oil in proportion to the increase or decrease in applied current, and a proportional electromagnetic pressure reducing valve that reduces the pressure of the supplied pressure oil in proportion to the increase or decrease in applied current. This invention relates to a proportional electromagnetic control valve and its control circuit.

[Conventional technology]

Normal electromagnetic pressure reducing valves only switch the hydraulic circuit of the pressure reducing valve ON and OFF by operating the electromagnetic coil, and in order to control the pressure to an arbitrary intermediate pressure reduction value, the discharge pressure (secondary pressure) is guided to the pilot and the discharge amount There is a method to control this.

Furthermore, when switching a control valve, particularly a flow direction switching valve, there is a system in which a hydraulic cylinder is used to drive the switching main spool in addition to manual operation or direct switching using a solenoid. In this case, pressure oil is supplied to and discharged from the hydraulic cylinder by a solenoid valve.

[Problem to be solved by the invention]

The pressure reducing valve mentioned above has no problem in obtaining a constant secondary pressure, but if the secondary pressure needs to be constantly changed, it is necessary to adjust the set pressure of the pilot pressure each time, which makes operation time-consuming. However, there are problems in that fine adjustment is difficult and the structure is complicated.

Also, in the case of a flow rate directional control valve, there are cases where it is necessary to change the direction and regulate the flow rate. to stop at any position and regulate the flow rate. For this purpose, it is preferable to use a pressure reducing valve as the electromagnetic valve and to change the secondary pressure arbitrarily, but changing the secondary pressure in the electromagnetic pressure reducing valve has problems as described above.

In view of this, an object of the present invention is to provide an electromagnetic pressure reducing valve (hereinafter referred to as a proportional electromagnetic pressure reducing valve) that can change the applied current and arbitrarily adjust the discharge pressure (secondary pressure) accordingly. do.

Further, in the present invention, the main spool of the directional control valve is shifted by cylinder pressure, and the cylinder pressure is regulated by the proportional electromagnetic pressure reducing valve, whereby the main spool can be moved to a stopped position.
An electromagnetic directional control valve (
The purpose of this invention is to provide a proportional solenoid control valve (hereinafter referred to as a proportional solenoid control valve).

A further object of the present invention is to provide a control circuit that can easily electrically operate the proportional electromagnetic control valve.

[! ! Means to solve the problem]

The proportional electromagnetic pressure reducing valve of the present invention for achieving the above object consists of a pressure reducing valve main body and an electromagnetic coil attached to the main body, and the pressure reducing valve main body includes a valve spool slidably inserted into a housing, and this spool. It is equipped with a main spring and a sub spring arranged at both ends, and the housing is provided with a drain hole and a pressure oil supply hole for the valve spool, and a pressure oil discharge hole is opened on the main spring side, so that the main spring The valve spool is pushed up, and the communication hole provided in the spool communicates the pressure oil discharge hole with the drain hole. The valve spool is moved in proportion to the auxiliary spring and against the main spring to cut off communication between the communication hole and the drain hole, communicate the pressure oil supply hole with the communication hole, and connect the drain hole with the pressure oil supply hole. The proportional electromagnetic control valve of the present invention is paired with the directional control valve body to reduce the opening area of the valve and increase the opening area with the pressure oil supply hole in proportion to the current applied to the proportional electromagnetic coil. The directional control valve body is equipped with a main spool that passes through the housing and a return spring that returns this main spool to the neutral position. Pressure oil is selectively supplied to the left and right cylinder ports by shifting the main spool. At the same time, a drive cylinder is provided on one side of the main spool, and passages are opened in both chambers of the drive cylinder that sandwich the piston, which are connected to respective pressure oil discharge holes of the electromagnetic pressure reducing valve. The reason is that the proportional electromagnetic pressure reducing valve shown in Section 1 is used. Note that a manual operating lever may be attached to the main spool on the side opposite to the drive cylinder.

In addition, the proportional solenoid control valve includes a directional control valve body and a pair of electromagnetic pressure reducing valves, and the directional control valve body includes a main spool that passes through the housing and a return spring that returns the main spool to a neutral position. Pressure oil is selectively supplied to the left and right cylinder ports by shifting the spools, and pressure chambers are formed on both sides of the main spool, and each pressure chamber is connected to the respective pressure oil discharge holes of the above pair of electromagnetic pressure reducing valves. The continuous passage may be opened, and the electromagnetic pressure reducing valve may be a proportional electromagnetic pressure reducing valve according to the first aspect.

Furthermore, in a proportional solenoid control valve having a pair of proportional solenoid pressure reducing valves, the control circuit for electrically operating the proportional solenoid valve of the present invention has a common applied power setting to the proportional solenoid coils of the pressure reducing valves. A controller is used to select and convert signals from the setting device into positive and negative signals centered on a neutral point, and to selectively apply an operating current to each proportional electromagnetic coil.

In addition, this control circuit is equipped with a position detector on the main spool for switching the pressure oil supply passage of the proportional solenoid control valve, and the detected position signal from the position detector is applied to the controller together with the operation signal from the applied power setting device. However, it is preferable to regulate the migration distance of the main spool.

Furthermore, this control circuit may be configured to operate each proportional electromagnetic coil via a dead zone setting circuit that does not issue an activation signal when the output signal from the common applied power setting device is within a predetermined range.

[For production]

In the above proportional pressure reducing valve, the pressing force of the valve spool is adjusted by adjusting the current applied to the electromagnetic coil, and when the discharge hydraulic pressure (secondary pressure) reaches a predetermined pressure, the valve spool is moved by the electromagnetic coil according to the secondary pressure. It is pushed up against the pressing force of , and the supply of pressure oil is stopped.

In addition, when the proportional solenoid control valve supplies pressure oil to the driving cylinder of the main spool, the proportional solenoid pressure reducing valve is used to regulate the supply pressure by the applied current, so the main spool position is determined by the balance between the supply pressure and the return spring. can be selected arbitrarily. This makes it possible to switch the supply of pressure oil to the left and right cylinder ports and to select the amount of oil to be supplied.

In this case, when the drive cylinder is provided at one end of the main spool, a manual operation handle can be attached to the other end so that manual operation can also be used.

Alternatively, the stop position of the main spool can be arbitrarily selected as described above by forming pressure chambers on both sides of the main spool and regulating the respective supply pressures using the proportional electromagnetic pressure reducing valves.

Furthermore, since the proportional solenoid control valve is operated by a common setting device, the operation is convenient and the external circuit configuration is simplified.

Further, by feeding back the detection signal from the main spool position detector to the control circuit, the control becomes highly accurate.

Further, by providing a dead band circuit in the control circuit, operability and safety are improved.

〔Example〕

FIG. 1 shows an embodiment of the proportional electromagnetic pressure reducing valve of the present invention. This proportional electromagnetic pressure reducing valve 1 includes a pressure reducing valve main body 2 and a proportional pressure reducing valve connected to this main body. 81 coil 3. In the pressure reducing valve body 2, a valve spool 5 is slidably inserted into a housing 4 along its axis, a main spring 7 is housed in a lower hollow hole 6 having a larger diameter, and a lower washer 8 is inserted. The washer 8 is slidably inserted into the lower hollow hole 6 and normally abuts against the stepped portion 9. Reference numeral 10 denotes a main spring support plug, which has a pressure oil discharge hole 11 that communicates with the lower hollow hole 6.

An upper hollow hole 15 with a larger diameter than the valve spool 5 is bored in the upper part of the housing 4, and a bushing rod 16 that contacts the upper end of the valve spool 5 and an output rod 17 of the proportional electromagnetic coil 3 are formed.
A spring receiver 18 connected to the bushing rod 16 is housed, and an auxiliary spring 19 is arranged between the bushing rod 16 and the spring receiver 18.

The valve spool 5 has a length that slightly protrudes into the upper hollow hole 15, and the auxiliary spring I9 has a slightly weaker spring pressure than the main spring 7, so that the valve spool 5 protrudes into the upper hollow hole 15 as shown in the figure. Retained.

A drain hole 20 and a pressure oil supply hole 21 are bored in the housing 4 relative to the valve spool 5, and a communication hole 22 that opens into the lower hollow hole 6 is bored in the valve spool 5. A continuous upper opening 23 and lower opening 24 are provided.

However, after the valve spool 5 is in the raised position as shown in the figure (when the proportional electromagnetic coil 3 is inactive as described later), the upper opening 23 communicates with the drain hole 20, and the lower opening 24 and the pressure oil supply hole 21 are connected to each other. It's blocked off. Further, when the proportional electromagnetic coil 3 is activated and the valve spool 5 is pushed down, the upper opening 23 and the drain hole 20 are cut off, and the lower opening 24
is communicated with the pressure oil supply hole 21.

In the figure, 25 indicates a load, which is connected to the pressure oil discharge hole 11.

In the above configuration, when the proportional electromagnetic coil 3 is not energized, the valve spool 5 is pushed up by the main spring 7 as shown in the figure, and the load device 25 communicates with the drain hole 20 via the communication hole 22 of the valve spool 5. .

Next, by energizing the proportional 1F magnetic coil 3, the output rod 17 descends and compresses the auxiliary spring 19, and when the spring pressure reaches a spring pressure higher than the main spring 7, the valve spool 5 is pushed down. Accordingly, the lower opening 23 and the drain hole 20 are cut off, and the lower opening 24 communicates with the pressure oil supply hole 21.

In this case, due to its characteristics, the proportional electromagnetic coil 3 lowers the output rod 17 and compresses the sub spring 19 in proportion to the supplied current, and when the applied current is gradually increased, the upper opening 23 and the drain hole 20 The communication area with the drain hole 20, that is, the opening area of the upper opening 23 with respect to the drain hole 20 gradually decreases until the opening area reaches O, and then the opening area of the lower opening 24 with respect to the pressure oil supply hole 21 gradually increases.

The state is shown in FIG. However, A indicates an opening area curve for the drain hole 20, B indicates an opening area curve for the pressure oil supply hole 21, and 0 point indicates a point where none is open.

Pressure oil is supplied to the load device 25 after being depressurized by the opening area formed in the above manner, and the pressure on the load device side (hereinafter referred to as secondary pressure, and the pressure of the supplied pressure oil is referred to as primary pressure) is applied to the lower washer. Therefore, a pushing force is applied to the valve spool 5 by the main spring 7 and the secondary pressure, and when the secondary pressure exceeds a predetermined value, the valve spool 5 is pushed up and the supply of pressure oil is stopped. At the same time, the lifting of the valve spool 5 also stops.

That is, the secondary pressure is proportional to the current applied to the proportional electromagnetic coil 3. Note that when the applied current is slightly reduced, the pressing force of the output rod 17 is also reduced, and accordingly, the valve spool 5 is pushed up, the upper opening 23 is communicated with the drain hole 20, and the pressure oil in the load device a25 is discharged. As a result, the secondary pressure decreases. Along with this, the valve spool 5 descends again, and the applied current and secondary pressure are maintained in a balanced state.

Next, FIG. 3 shows one side of a proportional electromagnetic control valve in which the above proportional electromagnetic pressure reducing valve is applied to a directional control valve. This proportional solenoid control valve 3
0 includes a directional control valve body 31 and a pair of the proportional electromagnetic pressure reducing valves 1a and lb. The directional control valve main body 31 is a well-known center bypass type 3-position spool valve, and a main spool 33 is inserted through a valve housing 32, and a high-pressure oil supply passage 35 connected to a high-pressure oil supply hole 34 is formed by horizontal movement of the spool 33.
The hydraulic oil passages 38, 39 connected to the left and right cylinder ports 36, 37, and the tank passage 41 connected to the tank boat 40 are selectively switched.This is a well-known structure and its explanation will be omitted. However, 42 is a center bypass passage.

One end of the main spool 33 protrudes from the valve housing 32 and constitutes a mounting portion 44 for the manual operation lever 45, and the other end projects into a cap 50 attached to the valve housing 32. This cap 50 has a pair of proportional electromagnetic pressure reducing valves 1a and 1.
A drive cylinder 51 is provided coaxially with the main spool 33, and the piston 5 is housed in this cylinder 51.
One end of the piston rod 63 with 2 is attached to the main spool 33
The other end protrudes into the spring cap 54,
A known neutral position return spring 55 is installed. Reference numeral 66 denotes a position detector for the main spool 33, which uses a potentiometer, for example, to convert the horizontal movement distance of the main spool 33 from the neutral position into an electric signal and transmits it, and is attached to the tip of the piston rod 53. .

The cap 50 has passages 62, 63 connecting the pressure oil discharge hole 11 (Fig. 1) of the proportional electromagnetic pressure reducing valve 1a+lb to each of the cylinder chambers 60, 61 that sandwich the piston 52.
form. 64 is a pilot pressure oil supply boat, which connects the pressure oil supply hole 21 of each proportional electromagnetic pressure reducing valve 1a, 1b.
is connected to via a supply path 65. Further, 66 is a drain circuit, which connects each of the pressure reducing valves 1a.

1b, and the other end is connected to the tank passage 41 via a discharge passage 67.

In the above configuration, each proportional electromagnetic pressure reducing valve 1a.

When lb is not energized, both cylinder chambers 60 and 61 are connected to the drain circuit 66 as described above, the main spool 33 is held in the neutral position by the return spring 55, and the main spool 33 is held in the neutral position by the manual operation lever 45. It is possible to move to the left or right of 33.

Next, when one of the proportional electromagnetic pressure reducing valves 1a is energized, the valve spool 5 moves in proportion to the applied current in the manner described above, and pilot pressure oil is supplied to the cylinder chamber 60, and the main spool 33 along with the piston 52 shifts to the right in the figure.

Accordingly, the return spring 65 is compressed and the cylinder chamber 60
The pressure in the cylinder chamber 60 increases, and the pressure reaction force increases on the valve spool 5 in the manner described above, and the pressure in the cylinder chamber 60 is maintained at a balanced position with the pressing force due to the applied current, that is, the pressure in the cylinder chamber 60 is maintained at a balance holding pressure. The main spool 33 is held in a corresponding position.

That is, the amount of movement of the main spool 33 from the neutral position is regulated in proportion to the T4 flow applied to the proportional electromagnetic pressure reducing valve 1a or lb.

Next, FIG. 4 shows another example of the proportional electromagnetic control valve.

The proportional electromagnetic control valve 70 of this embodiment has the proportional electromagnetic pressure reducing valves la and 1b disposed on both sides of a directional control valve body 71, and the directional control valve body 71 is housed in a valve housing 32 having the same structure as the previous example. It passes through the main spool 72. This main spool 72 has the same structure as the main spool 33 of the previous example except for the structure of the manual operation lever attachment part 44. However, 3a and 3b are proportional electromagnetic coils.

Left and right caps 73 and 74 are attached to both sides of the valve housing 32. One cap 73 has a proportional solenoid pressure reducing valve 1.
a and into which one end of the main spool 72 is inserted as a plunger. 76 is a pressure oil supply hole connected to the pilot pressure oil supply boat 77, 78 is a passage that leads the discharge pressure oil of the proportional electromagnetic pressure reducing valve 1a to the pressure chamber 75, and 79 is a drain circuit that communicates with the tank passage 41.

A proportional electromagnetic pressure reducing valve 1b is attached to the other cap 74, and a pressure chamber 80 is provided coaxially with the main spool 72.
0 houses a piston 81 connected to the main spool 72,
A return spring 55 and a position detector 56 having the same structure as described above are attached to the piston rod 82 connected to the piston 81.

83 is a pressure oil supply hole connected to the pilot pressure oil supply boat 84, and 85 is a pressure oil supply hole connected to the pilot pressure oil supply boat 84, and 85 is a pressure chamber 80 on the opposite side of the main spool 72 with the piston 81 in between.
A passageway 86 leading to the tank passageway 41 is connected to the tank passageway 41 through a drain circuit.

The rest of the structure is the same as that of the previous example, and the same parts are given the same reference numerals and explanations will be omitted.

The proportional electromagnetic control valve 70 of this embodiment only has a pair of proportional electromagnetic pressure reducing valves 1a and 1b installed separately on the left and right sides of the directional control valve main body 71, and has no effect except for operation by the manual operation lever 45 of the previous example. They are the same, and their explanation will be omitted.

Next, Figure 5 shows a pair of proportional electromagnetic pressure reducing valves shown in Figures 3 and 4 above! It is a control circuit diagram of a and lb. This control circuit 100 includes each pressure reducing valve 1a.

A common applied power setting device 101 for the proportional electromagnetic coils 3a and 3b of 1b is provided. This setting device 101 uses, for example, a volume control with the center as the neutral point,
By rotating the sliding piece from the central neutral point to one side, a positive potential is sequentially increased and emitted, and when the sliding piece is rotated to the opposite side, an increased negative potential is emitted, which is detected by the controller 102. However, one potential, for example, a positive potential, is applied to the power amplification circuit 103 for the proportional electromagnetic coil 3a.
Further, the negative potential is applied as an electric signal to the power amplification circuit 104 for the proportional electromagnetic coil 3b. That is, by selecting the rotation direction and rotation angle of the sliding piece of the setting device 101, it is possible to select either the proportional electromagnetic pressure reducing valve 1a or 1b and adjust the applied current.

In this case, even if the sliding piece of the setting device 101 is rotated to the target value of the main spool transition distance, the transition may not always be as desired. In this case, as shown in each of the above embodiments, the main spool 33 or 72 is provided with a position detector 56, and the signal from the detector is fed back to the controller 102.
Accurate position control of the main spool is possible by calculating and adding the deviation value in the controller. In the figure, 105 is a dead band setting circuit, which allows the setting device 101 to set a certain range left and right (plus or minus) from the neutral position. This circuit intentionally creates an electrically uncontrollable area (play) in the left/right switch, and is designed to improve operability and safety when switching between left and right.

Further, 106 is a dither signal generator, and even if a minute operating current is applied to each proportional electromagnetic pressure reducing valve, the valve spool 5 may not operate smoothly. In order to improve this, the valve spool 5 is slightly vibrated by superimposing a high frequency on the operating current.

〔Effect of the invention〕

The present invention has the following effects.

Since the proportional electromagnetic pressure reducing valve according to the present invention always communicates the pressure oil discharge side with the drain hole, it is easy to operate the load device connected to the discharge side by manual operation or the like. In addition, since a proportional electromagnetic coil is used to operate the valve spool, the spool is moved according to the applied current to arbitrarily regulate the amount of pressure oil discharged from the pressure oil discharge side and the amount of pressure oil supplied to the pressure oil discharge side. and when the pressure on the discharge side rises to a predetermined pressure,
By balancing this pressure with the spool pressing force due to the applied current, supply and discharge of pressure oil can be stopped and the pressure can be maintained at a predetermined pressure.

Further, the proportional electromagnetic control valve according to the present invention is composed of one directional control valve main body and the above-mentioned proportional electromagnetic pressure reducing valve paired with each other, and the pressure reducing valve sets the pressure of the pilot oil sent out by the applied current to a predetermined pressure, and controls the direction. Returning the valve body to the neutral position with respect to the main spool The main spool is moved by compressing the spring, and the main spool is stopped at the balance position with the spring, so by changing the pilot oil delivery pressure. The stop position of the main spool, that is, the movement of the main spool, allows switching of the direction of hydraulic fluid delivery and regulation of the amount of delivery as desired.

In this case, when the dual proportional electromagnetic pressure reducing valve is provided on one side of the main spool, a manual operating lever can be attached to the other side of the main spool. However, a pair of pressure reducing valves may be provided on both sides of the directional control valve body.

Further, since the control circuit for the proportional electromagnetic control valve is selectively operated by a common applied power setting device for both proportional electromagnetic pressure reducing valves, the operation is simple and the circuit can be simplified.

Further, by providing a main spool shift position detector in this control circuit and feeding back the detection signal, the main spool position can be accurately controlled.

Furthermore, by providing a dead zone setting circuit in the control circuit, erroneous operations can be prevented and operability and safety can be improved.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of a proportional electromagnetic pressure reducing valve according to the present invention;
The figure shows the relationship between the migration distance of the valve spool of the pressure reducing valve and the opening area of the drain hole and pressure oil supply hole, FIG. 3 is a longitudinal cross-sectional view of the proportional electromagnetic control valve according to the present invention, and FIG. FIG. 5 is a longitudinal sectional view of the proportional solenoid control valve according to the embodiment, and FIG. 5 is a control circuit diagram of the proportional solenoid control valve. 1.1a, lb are proportional electromagnetic pressure reducing valves, 2 is the pressure reducing valve body, 3
is the proportional electromagnetic coil, 4 is the housing, 5 is the valve spool, 7
is the main spring, 11 is the pressure oil discharge hole, 19 is the sub spring, 20 is the drain hole, 21 is the pressure oil supply hole, 22 is the communication hole, 30.70 is the proportional electromagnetic control valve, 31.71 is the directional control valve body , 32 is the housing, 33.72 is the main spool,
36.37 is a cylinder port, 51 is a drive cylinder, 5
2 is a piston, 55 is a return spring, 56 is a position detector, 6
0.61 is the cylinder chamber, 62.63 is the passage, 75.80
is a pressure chamber, 78.85 is a passage, 100 is a control circuit, 10
1 is an applied power setting device, 102 is a controller, and 106 is a dead zone setting circuit. Figure 1 20: Doshin Jmu 21: ffi kashiyui 3fX final whitezam 22: place stone

Claims (1)

[Claims] (1) The pressure reducing valve body is composed of a pressure reducing valve body and an electromagnetic coil attached to the body, and the pressure reducing valve body is composed of a valve spool slidably inserted into a housing, and a main body disposed at both ends of this spool. It is equipped with a spring and an auxiliary spring, and the housing is provided with a drain hole and a pressure oil supply hole for the valve spool,
A pressure oil discharge hole is opened on the main spring side, the valve spool is pushed up by the main spring, the pressure oil discharge hole and the drain hole are communicated through a communication hole provided in the spool, and the electromagnetic coil is configured as a proportional electromagnetic coil. , is disposed relative to the secondary spring, and the electromagnetic coil moves the valve spool through the secondary spring and against the primary spring in proportion to the applied current, thereby cutting off communication between the communication hole and the drain hole. While communicating the pressure oil supply hole and the communication hole,
A proportional electromagnetic pressure reducing valve characterized in that the opening area with the drain hole is reduced and the opening area with the pressure oil supply hole is increased in proportion to the current applied to the proportional electromagnetic coil. (2) The directional control valve body is equipped with an electromagnetic pressure reducing valve paired with the directional control valve body, and the directional control valve body is equipped with a main spool that passes through the housing and a return spring that returns this main spool to a neutral position, and when the main spool moves, In addition to selectively supplying supply pressure oil to the left and right cylinder ports, one side of the main spool is equipped with a drive cylinder, and the drive cylinder has both chambers sandwiching the piston, which are connected to the respective pressure oil discharge holes of the electromagnetic pressure reducing valve. A proportional electromagnetic control valve having an open passage, wherein the electromagnetic pressure reducing valve is the proportional electromagnetic pressure reducing valve according to claim 1. (3) The proportional electromagnetic control valve according to claim 2, wherein a drive cylinder is provided on one side of the main spool, and a manual operation lever is provided on the other side of the main spool. (4) comprising a directional control valve body and a pair of electromagnetic pressure reducing valves, the directional control valve body comprising a main spool penetrating the housing and a return spring for returning the main spool to a neutral position;
Pressure oil is selectively supplied to the left and right cylinder ports by shifting the main spool, and pressure chambers are formed on both sides of the main spool, and each pressure chamber has a pressure oil discharge hole for each of the above pairs of electromagnetic pressure reducing valves. At the same time as opening a passage leading to
A proportional electromagnetic control valve, wherein the electromagnetic pressure reducing valve is a proportional electromagnetic pressure reducing valve according to claim 1. (5) In a proportional electromagnetic control valve equipped with a pair of proportional electromagnetic pressure reducing valves, the proportional electromagnetic coils of the pressure reducing valves are equipped with a common applied power setting device, and the signal from the setting device is applied to a neutral point by a controller. A control circuit for a proportional electromagnetic control valve characterized by sorting and converting into positive and negative as a center and selectively applying an operating current to each proportional electromagnetic coil. (6) The main spool for switching the pressure oil supply path of the proportional solenoid control valve is equipped with a position detector, and the detected position signal from the position detector is applied to the controller together with the operation signal from the applied power setting device, 6. A control circuit for a proportional electromagnetic control valve according to claim 5, which regulates the moving distance of the spool. (7) The proportional electromagnetic coils according to claims 5 and 6 are operated through a dead zone setting circuit that does not issue an operating signal when the output signal from the common applied power setting device is within a predetermined range. Control circuit for proportional solenoid control valve.