JPH11184534A - Electric-fluid pressure regulator - Google Patents

Abstract

(57) [Problem] To provide an economical electric-fluid pressure regulator that can obtain high control accuracy even when a piston type is adopted as a pressure receiving body. SOLUTION: A main valve portion 1 of the electric-fluid pressure regulator R1 controls communication between ports 12, 13, 14. The pressure detecting means 65 converts the pressure of the pilot fluid into an electric signal and outputs it as a pressure detection signal. The control means 66 outputs a solenoid valve drive signal generated based on a result of comparison between an input signal from an external device and a pressure detection signal. The supply solenoid valve 63 and the discharge solenoid valve 64 output the pilot fluid at a predetermined pressure by on / off control based on the solenoid valve drive signal. The control means 66 is provided with a pulsating means 74. Therefore, at least one of the input signal and the pressure detection signal is pulsated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electric-fluid pressure regulator.

[0002]

2. Description of the Related Art Conventionally, a main valve, a pressure detecting means, an electromagnetic valve, a control means and the like are provided, and a main valve is provided based on a differential pressure between a feedback pressure fed back from an output port side of the main valve and a pressure of a pilot fluid. 2. Description of the Related Art An electro-hydraulic pressure regulator that performs proportional control of a valve section is known. Examples of this type of electro-fluid pressure regulator include, for example, Japanese Utility Model Laid-Open No. 62-109209, Japanese Utility Model Laid-Open No. 1-72613, and Japanese Utility Model Laid-Open No. 7-1808.
No. 3, JP-A-53-136187, and the like. For convenience, these are first,
These are referred to as second, third and fourth prior arts.

[0003] These four conventional techniques have in common that control is performed by comparing an input signal from an external device with a pressure detection signal from a pressure detecting means. further,
In the first, second and third prior arts, the pressure receiving body constituting the main valve is of a piston type. Therefore, the feedback pressure and the pilot pressure act on both end surfaces of the piston. Further, in the first, second, and third conventional techniques, one three-way valve is used as an electromagnetic valve that is controlled to be on and off based on a signal from a control unit. Therefore, the three-way valve is configured to output the pilot fluid at a predetermined pressure. On the other hand, in the fourth prior art, by using two two-way valves, they function as electromagnetic valves for air supply and exhaust.

[0004]

However, when the three-way valve is set to one,
In the method of generating pilot pressure by using a plurality of pilot fluids, a large amount of pilot fluid is consumed because the structure is not in a state of non-communication between all ports, which is extremely uneconomical. Further, in the three-way valve, the supply and exhaust are constantly performed by the high-speed switching of the flow path, and as a result, the pilot pressure pulsates greatly, and the pressure on the output port side in the main valve portion is likely to pulsate. This has caused a deterioration in control accuracy. Moreover, such pulsation of the pilot pressure
Because it is determined by mechanical factors such as the responsiveness of the solenoid valve, the flow rate of the pilot fluid, and the volume of the pilot chamber,
It was extremely unstable and unadjustable.

On the other hand, in the system in which the pilot pressure is generated by using two two-way valves, there is no pulsation of the pilot pressure from the structural point of view, so there is no fear that the pressure at the output port side in the main valve portion pulsates. However, if the pressure receiving member is a piston type, the dither effect due to the pulsation of the pilot pressure cannot be obtained, so that there is a problem that the sliding resistance of the piston increases, and as a result, the control accuracy deteriorates.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an economical electric-fluid pressure regulator which can obtain high control accuracy even when a piston type is adopted as a pressure receiving body. Is to do.

[0007]

In order to solve the above problems, according to the first aspect of the present invention, there is provided a main valve section for controlling communication between an input port, an output port and a discharge port, and a pressure of a pilot fluid. To an electric signal and output the same as a pressure detection signal, and control to output an electromagnetic valve drive signal generated based on a comparison result between the input signal input from an external device and the pressure detection signal. Means, and a supply solenoid valve and a discharge solenoid valve that output the pilot fluid at a predetermined pressure by being turned on and off based on the solenoid valve drive signal, and the feedback pressure fed back from the output port side. An electro-hydraulic pressure regulator that performs proportional control of the main valve section based on a pressure difference between the pressure of the pilot fluid and the pressure of the pilot fluid. An electro-fluid pressure regulator characterized in that both the valves are two-way valves and pulsation means for pulsating at least one of the input signal and the pressure detection signal is provided in the control means. I do.

According to a second aspect of the present invention, in the first aspect, the pulsating means includes an oscillating circuit for generating an oscillating signal, and the oscillating signal is transmitted to at least one of the input signal and the pressure detection signal. An adder is added to one side.

According to a third aspect of the present invention, in the second aspect, the oscillation signal is added to at least one of the two signals at a stage before comparing the input signal and the pressure detection signal. I decided to do it.

According to a fourth aspect of the present invention, in the first aspect, the control means includes: a differential amplifier circuit for amplifying the pressure detection signal from the pressure detection means; An input circuit for converting the input signal into a state suitable for the comparison operation, a first and a second comparison circuit for receiving the converted input signal and the amplified pressure detection signal and comparing the magnitudes thereof; A first output for generating a first solenoid valve drive signal for controlling the supply solenoid valve to be turned on and off based on the comparison signal output from the first comparison circuit and outputting the signal to the supply solenoid valve; A circuit and the second
A second output circuit that generates a second solenoid valve drive signal for controlling the on / off of the discharge solenoid valve based on the comparison signal output from the comparison circuit, and outputs the signal to the discharge solenoid valve; An oscillation circuit for generating an oscillation signal having a constant amplitude;
The control circuit includes an adder that adds the oscillation signal to at least one of the converted input signal and the amplified pressure detection signal immediately before the comparison circuit.

Hereinafter, the "action" of the present invention will be described. According to the present invention, at least one of the input signal and the pressure detection signal is pulsated by the pulsation means of the control means, and as a result, the electromagnetic valve drive signal also pulsates. Therefore, the pressure of the pilot fluid can be pulsated despite the fact that a two-way valve which does not inherently generate pulsation is used. In this case, the amplitude and frequency of the pulsation of the pilot pressure can be adjusted only by setting the conditions of the pulsation means. For this reason, there is no influence from mechanical elements in the main valve section and the like, and the pulsation of the pilot pressure is stabilized.

When the piston type is adopted as the pressure receiving member, a suitable dither effect can be obtained. Therefore, by setting the pulsation of the pilot pressure to a minimum necessary value,
The sliding resistance of the piston and the hysteresis of the main valve portion can be reduced. Therefore, the control accuracy is definitely improved.

Further, since both the supply solenoid valve and the discharge solenoid valve are two-way valves, it is possible to make all ports non-communicating. Therefore, unlike the conventional system in which the pilot pressure is generated by using one three-way valve, a large amount of pilot fluid is not consumed, which is economical.

According to the second aspect of the invention, the adder adds the oscillation signal generated by the oscillation circuit to at least one of the input signal and the pressure detection signal, so that the signal is pulsated. As a result, a pulsating solenoid valve drive signal is obtained, and the solenoid valve driven by the signal generates a pilot pressure that pulsates regularly and stably.

According to the third aspect of the present invention, if the oscillation signal is added before the comparison between the input signal and the pressure detection signal, the amplitude and frequency of the pulsation of the pilot pressure can be adjusted. It can be done more easily.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment An electric-pneumatic regulator (electropneumatic regulator) R1 according to a first embodiment of the present invention will be described in detail with reference to FIGS. .

First, the configuration of the main valve section 1 will be described.
As shown in FIG. 3, the housing 2 constituting the main valve portion 1 in the present embodiment includes four blocks 3, 4, 5,
Consists of six. The first block 3 has a lid shape and is joined to the lower surface side of the second block 4. The third block 5 is joined to the upper surface of the second block 3. The fourth block 6 also has a lid shape and is joined to the upper surface of the third block 5. A packing 7 is interposed at the interface between the fourth block 6 and the third block 5.

Inside the second block 4, there is formed a central through hole 11 which forms a part of an internal flow path 10 through which air (air) as a fluid can flow. The central through-hole 11 extends in the vertical direction of the block 4. Second block 4
Are formed on the side face of the port 3, an input port 12, an output port 13, and an exhaust port 14. These ports 1
Each of 2, 13, and 14 communicates with the internal flow path 10. A pilot port 15 for discharging a pilot fluid is formed on a side surface of the fourth block 6.

The third block 5 has a concave portion on the upper surface side. Accordingly, when the third block 5 and the fourth block 6 are joined, the piston housing space 16 is formed by the two 5 and 6. A piston 17 as a pressure receiving body is housed in the piston housing space 16 so as to be slidable in the vertical direction.
The piston 17 partitions the piston housing space 16 into two chambers 21 and 22. That is, of the chambers 21 and 22, the one partitioned on the lower surface side of the piston 17 is the feedback chamber 21, and the one partitioned on the upper surface side of the piston 17 is the pilot chamber 22. As a result, the piston 17
The feedback pressure P1 acts on the lower end face of the piston 17, and the pressure of the pilot fluid (ie, pilot pressure P2) acts on the upper end face of the piston 17. In addition, the feedback chamber 21 and the output port 13 are communicated via a feedback pressure introduction path 23. The introduction path 23 is connected to the output port 1
It serves to supply the feedback pressure P1 returned from the third side into the feedback chamber 21.

The piston 17 is connected to a base end (ie, upper end) of a displacement transmission rod 25 as a displacement transmission body. More specifically, the connection between the two members 17 and 25 is achieved by tightening bolts in a state where the male screw portion at the upper end of the rod 25 is inserted into the center hole of the piston 17. The rod 25 extends along the vertical direction of the electropneumatic regulator 1 and protrudes toward the center through hole 11. The center line of the rod 25 substantially matches the center axis of the central through hole 11.

The electropneumatic regulator 1 includes a pair of sleeves 26 and 27. The first sleeve 26 has a cylindrical shape, and is disposed so as to contact the upper end surface of the first block 3 at the lower end of the central through hole 11. The second sleeve 27 has a cylindrical shape, and is provided so as to contact the lower end surface of the third block 5 at the upper end of the central through hole 11.

The outer peripheral surface of the first sleeve 26 and the central through hole 1
An annular packing 28 is interposed between the inner packing 1 and the inner peripheral surface. Outer peripheral surface of second sleeve 27 and central through hole 11
Similarly, an annular packing 28 is interposed between the inner peripheral surface and the inner peripheral surface.

On the inner peripheral surfaces of these sleeves 26 and 27, an annular holding groove 29 is formed. The holding groove 2
9 includes annular packings 30 and 3 as sealing members.
1 is held so as not to be displaced. The second sleeve 27 is further provided with an annular packing 32 for sealing between the inner peripheral surface of the second sleeve 27 and the outer peripheral surface of the rod 25.

The electropneumatic regulator 1 includes a pair of valve bodies 3
6,37. First valve element 36 serving as an air supply valve element
Are slidably inserted into the first sleeve 26 via the first packing 30. The second valve body 37, which is an exhaust valve body, is slidably inserted into the second sleeve 27 via the second packing 31.

The structure of the first valve body 36 and the second valve body 37 is as follows.
This is the same in the present embodiment. Both valve bodies 36 and 37 are substantially cylindrical members whose outer peripheral surfaces are simple curved surfaces, and have valve tops 38 and 39 on one end surface. The first valve body 36 is arranged such that the valve top 38 faces upward, and the second valve body 37 is arranged such that the valve top 39 faces downward.

These valve elements 36 and 37 have spring receiving recesses 40. The spring accommodating recess 40 is open at an end surface of the valve bodies 36 and 37 on the side where the valve tops 38 and 39 are not provided. The spring accommodating recess 40 and the end face side where the valve tops 38 and 39 are provided are communicated via a communication hole 41. The communication hole 41 has one valve body 36, 37.
, And are arranged circumferentially and at equal intervals except for the center of the end face. The reason for excluding the center of the end face is
This is for securing the contact area or the insertion area of the rod 25.

In the present embodiment, the valve top 38 belonging to the first valve body 36 is provided between the inner peripheral surface of the first packing 30 and the valve body 3.
6 is formed over the entire outer peripheral edge of the upper end surface of the valve body 36 so as to have the same positional relationship as the seal surface formed by the outer peripheral surface of the valve body 6. The valve top 39 belonging to the second valve body 37 is provided between the inner peripheral surface of the second packing 31 and the valve body 3.
The lower end surface of the valve body 37 is formed over the entire outer peripheral edge thereof so as to have a positional relationship on the same circumference as the sealing surface formed by the outer peripheral surface of the valve 7. Therefore, both valve bodies 36, 3
No. 7 has a structure in which the thrust resulting from the air pressure acting on one end face side and the thrust resulting from the air pressure acting on the other end face side cancel each other. In both the valve bodies 36 and 37, the effective pressure receiving areas on both end faces are equal. The area defined by inserting the first valve body 36 through the first sleeve 26 is called a first back pressure chamber 42, and the area defined by inserting the second valve body 37 through the second sleeve 27. Is referred to as a second back pressure chamber 43. The air flowing through the internal flow path 10 is supplied to the first back pressure chamber 42 and the second back pressure chamber 43 through the respective communication holes 41.
Can flow into the side.

The center through hole 11 of the electropneumatic regulator 1
The first and second valve seat members 44, 45
Is provided. These valve seat members 44 and 45 are cylindrical members, and are both immovably attached to the inner wall surface of the central through hole 11. The first valve seat member 44 is located at a position where the valve top 38 of the first valve body 36 can come and go,
Specifically, it is located between the input port 12 and the output port 13 in the internal flow path 10. Second valve seat member 45
Is located at a position where the valve top 39 of the second valve body 37 can come and go, specifically, in a region between the output port 13 and the exhaust port 14 in the internal flow path 10. A disc-shaped elastic body 46 as a contacted portion is provided on the outer peripheral portion of the lower end surface of the first valve seat member 44.
Are arranged. Similarly, a disc-shaped elastic body 46 as a contacted portion is also provided on the outer peripheral portion of the upper end surface of the second valve seat member 45. The inner diameter of the elastic body 46 is the valve top 38,
The diameter of the elastic body 46 is set smaller than the diameter of the valve 39 (that is, the seal diameter of the packings 30 and 31).
39 is set to be larger than the diameter. The first and second valve seat members 44 and 45 may be formed of one member.

The electropneumatic regulator 1 has a pair of springs 51 and 52 as urging means. The first spring 51 is housed in the spring housing recess 40 of the first valve body 36. The second spring 52 is connected to the rod 25
Is accommodated in the spring accommodating recess 40 of the second valve body 37 in a state where it is inserted. The first spring 51 constantly urges the first valve body 36 in a direction in which the valve top 38 contacts the first valve seat member 44, that is, upward. The second spring 52 constantly urges the second valve body 37 in a direction in which the valve top 39 contacts the second valve seat member 45, that is, downward.

The distal end surface (that is, the lower end surface) of the displacement transmission rod 25 reaches near the lower end surface of the first valve seat member 44. On the outer peripheral surface of the rod 25, near the upper end surface of the second valve seat member 45, a mounting groove 54 is formed along the circumferential direction. A substantially C-shaped engagement ring 53 as an engagement portion is fitted in the mounting groove 54. The engagement ring 53 is in a state of protruding from the outer peripheral surface of the rod 25. The engagement ring 53 has a positional relationship that allows the engagement ring 53 to approach and separate from the lower end surface of the first valve body 36.

As shown in FIG. 3, in the case of this electropneumatic regulator R1, a cover 61 is provided on the upper surface of the fourth block 6.
Are joined. At the interface between the cover 61 and the fourth block 6, a packing 62 is interposed,
An accommodation space is formed by 1,6. Inside the accommodation space, a supply solenoid valve 63, a discharge solenoid valve 64,
Electrical components such as a pressure sensor 65 as pressure detection means and a control circuit 66 as control means are accommodated.
The supply solenoid valve 63 and the discharge solenoid valve 64 are both normally closed two-way valves. These solenoid valves 63, 6
Reference numeral 4 controls the on / off of the pilot fluid based on the solenoid valve drive signal to output the pilot fluid at a predetermined pressure. The pressure sensor 65 converts the pressure P2 of the pilot fluid into an electric signal and outputs it as a pressure detection signal. In the present embodiment, a pressure sensor 65 is used in which elements whose resistance values change due to pressure changes are connected in a bridge.

The first port of the supply solenoid valve 63 communicates with the input port 12 via a passage (not shown). The second port of the discharge solenoid valve 64 communicates with the pilot port 15 via a passage (not shown). Supply solenoid valve 6
The second port 3 and the first port of the discharge solenoid valve 64 communicate with each other. The connection point between the two ports is further connected to a pilot chamber 22 through a pilot pressure introduction passage (not shown).
Is in communication with And the pressure receiving part of the pressure sensor 65 is:
It is provided at the connection point to detect the pressure P2 of the pilot fluid.

When the solenoid of the supply solenoid valve 63 is in the excited state and the solenoid of the discharge solenoid valve 64 is in the demagnetized state, the air on the supply port 12 side flows in through the supply solenoid valve 64 while the exhaust Air does not flow out to the pilot port 15 via the solenoid valve 64 for use. Therefore, the pressure at the connection point increases, and the pilot pressure P2 in the pilot chamber 22 also increases. When the solenoid of the supply solenoid valve 63 is in the demagnetized state and the solenoid of the discharge solenoid valve 64 is in the excited state, air does not flow into the input port 12 side through the supply solenoid valve 64, but the exhaust solenoid Pilot port 15 via valve 64
Outflow of air to the air occurs. Therefore, the pressure at the connection point becomes low, and the pilot pressure P in the pilot chamber 22 is reduced.
2 will be lower as well. When the solenoid of the supply solenoid valve 63 and the solenoid of the discharge solenoid valve 64 are both in the demagnetized state, the inflow and outflow of air through both solenoid valves 63 and 64 does not occur. Therefore, the pressure at the connection point does not change, and the pilot pressure P2 in the pilot chamber 22 does not change. In this embodiment, the supply solenoid valve 63 is used.
The discharge solenoid valve 64 constitutes pilot pressure adjusting means.

Here, the main valve 1 constructed as described above is used.
Will be described. FIG. 3 shows the feedback pressure P
1 and pilot pressure P2 are equal, and the differential pressure P1-P2
Shows a state (neutral state) when is zero. At this time, since both pressures P1 and P2 are balanced,
Driving force does not act on both end surfaces of the piston 17 in any of up and down directions. Accordingly, no displacement occurs in the rod 25 connected to the piston 17, and the rod 25 maintains the neutral position. In this case, the distal end surface of the rod 25 is the first
It is separated from the center of the upper end face of the valve body 36 by a certain gap. Therefore, the first valve body 36 is pressed to the upper position only by the action of the spring force of the first spring 51, and the valve top 38 of the first valve body 36 and the elastic body 4 of the first valve seat member 44.
6 is in a state of contact. In addition, although the thrust acts by the same magnitude of air pressure acting on both end surfaces of the valve body 36, they cancel each other.

The locking ring 53 projecting from the outer peripheral surface of the rod 25 is in contact with the lower end surface of the second valve body 37. The second valve body 37 is pressed to the lower position only by the spring force of the second spring 52, and the valve top 39 of the second valve body 37 is pressed.
And the elastic body 46 of the second valve seat member 45 comes into contact with each other. Although thrusts are exerted on both end faces of the valve element 37 by the same magnitude of air pressure acting thereon, they cancel each other.

As a result, the first valve body 36 contacts the first valve seat member 44 and the second valve body 37 contacts the second valve seat member 45. Will be shut off.

The feedback pressure P1 is equal to the pilot pressure P2.
In the air supply state in which the pressure difference P1 -P2 takes a negative value, a downward driving force acts on the piston 17 in the figure. The displacement transmission rod 25 is displaced downward accordingly. In that case, the rod end face presses the first valve body 36 downward against the spring force of the first spring 51,
The valve top 38 is separated from the elastic body 46 of the first valve seat member 44. As a result, the state is switched from the neutral state to the air supply state. The input port 12 and the output port 13 communicate with each other at a valve opening corresponding to the displacement of the rod 25 at this time. At this time, no displacement is transmitted from the rod 25 to the second valve body 37, so that the space between the output port 13 and the exhaust port 14 is still shut off.

When the air supplied from the input port 12 reaches the output port 13 and the air pressure on the output port 13 gradually increases, the feedback pressure P1 increases accordingly. Then, the value of the absolute value of the differential pressure P1 -P2 becomes smaller, so that the piston 17 and the rod 25 are displaced upward this time, and work to reduce the valve opening of the first valve body 36.

The feedback pressure P1 is equal to the pilot pressure P2.
In the exhaust state where the pressure difference P1 -P2 takes a positive value, an upward driving force acts on the piston 17 in FIG. The displacement transmission rod 25 is accordingly displaced upward. In this case, the engagement ring 53 presses the second valve body 37 upward against the spring force of the second spring 52, and the valve top 39 is moved to the elastic body 4 of the second valve seat member 45.
Separated from 6. As a result, the state is switched from the neutral state to the exhaust state. The output port 13 and the exhaust port 14 communicate with each other at a valve opening corresponding to the displacement of the rod 25 at this time. At this time, the first valve body 36
Since no displacement is transmitted from 5, the connection between the input port 12 and the output port 13 is still shut off.

The air on the output port 13 side is exhaust port 14
When the air pressure on the output port 13 side gradually decreases, the feedback pressure P1 decreases accordingly. Then, the value of the absolute value of the differential pressure P1-P2 becomes smaller, so that the piston 17 and the rod 25 are displaced downward, and
It works so as to reduce the valve opening of the second valve body 37.

That is, even if the air supply state or the exhaust state is established, control is performed so that the neutral state shown in FIG. In other words, an air pressure proportional to the pilot pressure P2 is always obtained from the output port 13 side.

Next, the configuration of the control circuit 66 in this embodiment will be described. As shown in FIG. 1, a control circuit 66 as a control means includes a power supply circuit 67, a differential amplifier circuit 68, an input circuit 69, a first comparison circuit 70, a second comparison circuit 71, and a first output circuit. 72, second output circuit 73
And pulsating means 74. Also, the pulsating means 7
4 comprises an oscillation circuit 75 and an adder 76.

The power supply circuit 67 is connected to a power supply and stably generates a DC current of a predetermined voltage. The input side of the differential amplifier circuit 68 as the amplifying unit is electrically connected to the output side of the pressure sensor 65. This differential amplifier circuit 68
A pressure detection signal from the pressure sensor 65 is input and differentially amplified. The input side of the input circuit 69 is electrically connected to an external device such as a sequencer. The input circuit 69 converts an input signal from an external device into a state suitable for a comparison operation in a subsequent stage.

In this embodiment, the following configuration is specifically adopted. That is, the pressure sensor 65 is configured by connecting thin film resistors in a bridge shape. Therefore, when pressure is applied thereto, distortion occurs, and the resistance value changes. Since this change is insignificant, it is usually configured as a Wheatstone bridge circuit, and the differential amplifier circuit is a part of the constituent elements. With this circuit, a slight change in the resistance value is amplified and detected as a change in the voltage signal. The input signal corresponds to this pressure detection signal 1: 1
The input circuit 69 adjusts the zero point and the span.
Here, the adjustment function may be performed by the differential amplifier circuit 68 as a matter of course.

The output side of the differential amplifier circuit 68 is electrically connected to one input terminal of the first comparison circuit 70 and the second comparison circuit 71. The output side of the input circuit 69 is electrically connected to the other input terminals of the first comparison circuit 70 and the second comparison circuit 71 via the adder 76.

First comparison circuit 70 and second comparison circuit 7
Reference numeral 1 inputs the converted input signal and the amplified pressure detection signal, compares the magnitudes thereof, and outputs a predetermined comparison signal from the output terminal side. Note that the value of the converted input signal corresponds to a target pressure value, and the amplified pressure detection signal corresponds to an actual pressure value.

The output side of the first comparison circuit 70 is electrically connected to the input side of the first output circuit 72, and the output side of the second comparison circuit 71 is electrically connected to the input side of the second output circuit 73. Connected.

The first output circuit 72 is connected to the first comparison circuit 7
0 based on the comparison signal output from
And generates a first solenoid valve drive signal for controlling the on / off operation of the first solenoid valve, and outputs the signal to the supply solenoid valve 63. Specifically, when the value of the amplified pressure detection signal is larger than the value of the converted input signal (the actual pressure value is larger than the target pressure value), the first comparison circuit 70 outputs the L level signal. Is output. Conversely, when the value of the amplified pressure detection signal is smaller than the value of the converted input signal (the actual pressure value is smaller than the target pressure value), the first comparison circuit 70 outputs the H-level comparison signal. Is output. Therefore, in the former case, since the first output circuit 72 does not operate, the first output circuit 72 does not operate.
Is not generated. At this time, the supply electromagnetic valve 63 is controlled to be off (that is, the solenoid is demagnetized), so that the flow path is closed. In the latter case, since the first output circuit 72 operates, a first solenoid valve drive signal is generated. At this time, the supply solenoid valve 63 is controlled to be turned on (that is, the solenoid is excited), so that the flow path is opened.

The second output circuit 73 is connected to the second comparison circuit 7
1 based on the comparison signal output from
A second solenoid valve drive signal for controlling ON / OFF of the second solenoid valve is generated, and the signal is output to the discharge solenoid valve 64. Specifically, when the value of the amplified pressure detection signal is larger than the value of the converted input signal (the actual pressure value is larger than the target pressure value), the second comparison circuit 71 sets the H level. Is output. Conversely, when the value of the amplified pressure detection signal is smaller than the value of the converted input signal (the actual pressure value is smaller than the target pressure value), the second comparison circuit 71 outputs the L-level comparison signal. Is output. Therefore, in the former case, since the second output circuit 73 operates, a second solenoid valve drive signal is generated. At this time, the discharge solenoid valve 64 is controlled to be turned on (that is, the solenoid is excited).
Therefore, the flow path is in an open state. In the latter case, the second output circuit 73 does not operate, and the second solenoid valve drive signal is not generated. At this time, the discharge electromagnetic valve 64 is controlled to be turned off (that is, the solenoid is demagnetized), so that the flow path is closed.

From the above, when the actual pressure value is larger than the target pressure value, the pilot fluid is supplied to the discharge solenoid valve 6.
4 and the pilot pressure P2 is reduced. Conversely, when the actual pressure value is smaller than the target pressure value, the pilot fluid is supplied through the supply solenoid valve 63, so that the pilot pressure P2 increases.
In the present embodiment, the first and second comparison circuits 70,
A comparison / output unit is composed of the first output circuit 71 and the first and second output circuits 72 and 73.

FIG. 2 shows an example of the oscillation circuit 75 constituting the pulsating means 74. This oscillation circuit 75
It includes two operational amplifiers 81 and 82 as main components. From the point A between the output terminal of the first operational amplifier 81 in the preceding stage and the inverting input terminal of the second operational amplifier 82 in the subsequent stage, a square wave is output as an oscillation signal having a constant amplitude. Has become. From the point B on the output terminal side of the second operational amplifier, a triangular wave is output as an oscillation signal having a constant amplitude. That is, with such a circuit configuration, oscillation signals of two different waveforms can be obtained. In the present embodiment, a triangular wave among them is used as an oscillation signal. Of course, a square wave may be selected.

The amplitude and frequency of the oscillation signal generated by the oscillation circuit 75 are compared by, for example, changing the standards of the operational amplifiers 81 and 82 and changing the standards of components (diodes, resistors, capacitors, etc.) other than the operational amplifiers 81 and 82. The target can be easily adjusted. This means that the pilot pressure P
2 means that the pulsation amplitude and frequency can be arbitrarily adjusted by setting the conditions of the pulsation means 74.

The adder 76 constituting the pulsating means 74
The oscillating signal output from the oscillating circuit 75 is added to the converted input signal immediately before the first and second comparing circuits 70 and 71. As a result, the converted input signal is input to the first and second comparison circuits 70 and 71 after being in a pulsating state. The adder 76 can be constituted by a conventionally known circuit using an operational amplifier or the like. Similarly, the power supply circuit 67, the differential amplifier circuit 68, the input circuit 69, the comparison circuits 70 and 71, and the output circuits 72 and 73 can be basically configured by conventionally known circuits.

Then, the control circuit 66 having the above configuration
Then, as a result of performing the comparison operation based on the pulsated input signal, the first and second solenoid valve drive signals output via the comparison / output unit also pulsate. Accordingly, the pressure at the connection point of the two solenoid valves 63 and 64 (that is, the pilot pressure P2) also pulsates. For this reason, the pulsating pilot pressure P2 acts on the upper end surface of the piston 17 which is a pressure receiving member, whereby a suitable dither effect is given to the piston 17. Here, the pilot pressure P2
Is preferably set in advance to a necessary minimum size. The necessary minimum size specifically means a size that can provide a dither effect enough to reduce the sliding resistance of the piston 17 but hardly pulsates the control pressure output to the output port 13 side. I do.

Next, the characteristic effects of this embodiment will be listed. (A) The electropneumatic regulator R1 is characterized in that a pulsation means 74 is provided in the control circuit 66. Therefore, the two-way valve which does not inherently generate pulsation is connected to the supply solenoid valve 6.
Despite being used as the solenoid valve 3 and the discharge solenoid valve 64, the pilot pressure P2 can be reliably pulsated. In that case, the amplitude and frequency of the pulsation of the pilot pressure P2 can be adjusted only by setting the conditions of the pulsation means 74 as described above. For this reason, the amplitude and frequency of the pulsation of the pilot pressure P2 are controlled by the main valve 1 and the solenoid valve 6.
It is no longer affected by mechanical elements at 3,64. Therefore, the pulsation of the pilot pressure P2 is stabilized as compared with the conventional case. As a result, the hysteresis of the main valve portion 1 is reduced, and control accuracy can be reliably improved.

The electropneumatic regulator R1 of the present embodiment
Has adopted a piston system as a pressure receiving body. However, according to the above configuration, a suitable dither effect can be obtained, so that the sliding resistance of the piston 17 can be reduced by setting the pulsation of the pilot pressure P2 to the required minimum. As a result, the operation of the piston 17 becomes smooth. Even in this case, it is possible to keep the control pressure output to the output port 13 side from pulsating. Therefore, the hysteresis of the main valve portion 1 is reduced,
Control accuracy can also be reliably improved.

(B) Further, in the electropneumatic regulator R1 of this embodiment, since both the supply solenoid valve 63 and the discharge solenoid valve 64 are two-way valves, both solenoid valves 63, 64 are demagnetized by both solenoids. Is closed, it is possible to ensure that all ports of both solenoid valves 63 and 64 are in a non-communication state. Therefore, the pilot pressure P
Unlike the conventional method of generating 2, it does not consume a large amount of pilot fluid. Therefore, it can be extremely economical.

(C) The electropneumatic regulator R1 of the present embodiment
Has a pulsating means 74 including an oscillation circuit 75 for generating an oscillation signal having a constant amplitude, and an adder 76 for adding the oscillation signal to the converted input signal. Therefore,
As a result of the pulsation of the converted input signal, first and second solenoid valve drive signals which are also pulsated are obtained. Since both solenoid valves 63 and 64 are driven by such a signal, a pulsating pilot pressure P2 can be generated regularly and stably. The regular and stable pilot pressure P2 contributes to reducing the hysteresis of the main valve portion 1 and improving control accuracy.

(D) Electropneumatic regulator R1 of the present embodiment
In such a configuration, immediately before the first and second comparison circuits 70 and 71, an oscillation signal is added to the converted input signal. Therefore, compared to a configuration in which the oscillation signal is added at a stage after the comparison between the amplified pressure detection signal and the converted input signal, the pilot pressure P
2. The waveform, amplitude and frequency of the pulsation can be adjusted more easily. Of course, this also contributes to an improvement in control accuracy.

(E) In the present embodiment, the two valve bodies 36 and 37 in the main valve portion 1 have a thrust resulting from the air pressure acting on one end face and a result from the air pressure acting on the other end face. The resulting thrust cancels each other. Therefore, the configuration itself of the main valve portion 1 is originally suitable for high accuracy. That is, the valve element 36,
This is because there is no fear that the pressure counterbalance via 37 is lost, and the hysteresis does not worsen even when the valve body is eccentric due to machining tolerance. Therefore, if the control circuit 66 having the above configuration and the main valve portion 1 having the above configuration are used in combination, extremely high precision control can be realized by the synergistic action of both. Second Embodiment Next, an electropneumatic regulator R2 according to a second embodiment of the present invention will be described with reference to FIG.
Only the parts common to the first embodiment are given the same reference numerals, and parts different from the first embodiment will be mainly described.

Here, the structure of the main valve portion 1A is slightly different from that of the first embodiment. A pair of sleeves 26A, 27
Although A is immovably disposed in the central through-hole 11, the separation distance between the two 26A and 27A is somewhat smaller.

The first valve body 36A is slidably inserted into the first sleeve 26A via the first packing 30. The second valve body 37A is slidably inserted into the second sleeve 27A via the second packing 31.
Both valve bodies 36A and 37A are substantially cylindrical members,
One end face has valve tops 38 and 39. However, unlike the first embodiment, the first valve body 36A is
The second valve body 37A is arranged such that the valve top 39 faces upward.

Further, these valve bodies 36A, 37A do not have the spring accommodating recess 40, but instead have a spring contact stepped portion 89. The spring contact stepped portion 89 is provided between the valve tops 38, 3 on both valve bodies 36A, 37A.
9 is present on the end face on the side where it does not exist.

As in the first embodiment, the two valve bodies 36A and 37A are configured such that the thrust resulting from the air pressure acting on one end face and the thrust resulting from the air pressure acting on the other end face are mutually different. It has a structure to offset each other. That is, the valve top 38 belonging to the first valve body 36A has a positional relationship on the same circumference as the sealing surface formed by the inner peripheral surface of the first packing 30 and the outer peripheral surface of the valve body 36A. 36A is formed over the entire outer peripheral edge of the lower end face. The valve top portion 39 belonging to the second valve body 37A has a positional relationship on the same circumference as a sealing surface formed by the inner peripheral surface of the second packing 31 and the outer peripheral surface of the valve body 37A. The upper end face is formed over the entire outer peripheral edge.

The main valve section 1A of the present embodiment also includes the first and second valves.
Valve seat members 87 and 88 are provided in the internal flow path 10.
However, unlike Embodiment 1, both valve seat members 87,
88 is screwed on the rod 25 side, and can move integrally with the rod 25. For this reason, a male screw groove is formed on the outer peripheral surface of the rod 25. First valve seat member 8
7 is a position where the valve top 38 of the first valve body 36A can come and go,
Specifically, it is located immediately below the valve body 36A. The second valve seat member 88 is located at a position where the valve top 39 of the second valve body 37A can come and go, specifically, at a position immediately above the valve body 37A. In addition, the supply pressure on the input port 12 side is always applied to the lower end surface of the first valve seat member 87.

A spring 86 as an urging means is interposed between the two valve bodies 36A and 37A. The spring 86 constantly urges the pair of valve bodies 36A, 37A in a direction to separate them from each other. Therefore, in the neutral state, the valve top 38 comes into contact with the first valve seat member 44, and the valve top 39 comes into contact with the second valve seat member 45.

Now, the characteristic effects of the present embodiment will be enumerated. (A) Both valve elements 36 in this electropneumatic regulator R2
A and 37A also have a structure in which the thrust resulting from the air pressure acting on one end face and the thrust resulting from the air pressure acting on the other end face cancel each other. Therefore, the main valve portion 1A suitable for high accuracy is provided. Therefore, if the control circuit 66 having the above configuration and the main valve portion 1A having the above configuration are used in combination, extremely high precision control can be realized as in the first embodiment by the synergistic action of both.

(B) In the present embodiment, a configuration is employed in which the supply pressure on the input port 12 side is constantly applied to the lower end surface of the first valve seat member 87. Therefore, even when the pilot pressure P2 becomes zero, all the ports 12, 13, and 14 of the main valve portion 1A do not become shut off. That is, when no pilot pressure is applied, as a result of the upward thrust being applied to the first valve seat member 87, the rod 25 is held at a position slightly higher than the neutral position. For this reason, communication between the output port 13 and the discharge port 14 is ensured. Therefore, even when a fluid pressure cylinder is directly connected to the output port 13 of the electropneumatic regulator R2, residual pressure can be exhausted from the cylinder and manual operation of the cylinder is also possible. Therefore, there is an advantage that it is not necessary to provide a means for exhausting residual pressure between the cylinder and the electropneumatic regulator R2.

It should be noted that the present invention is not limited to the above embodiment, but can be modified to another form as follows, for example. ◎ In another example of the electropneumatic regulator R3 shown in FIG.
The arrangement position of the adder 76 is different from that of the above embodiment. That is, here, the adder 76 is provided between the differential amplifier circuit 68 and the first and second comparison circuits 70 and 71. Accordingly, as a result of the pulsation of the amplified pressure detection signal, the pilot pressure P2 can be similarly pulsated.

The pulsating means 74 is not limited to a means for pulsating at least one of the input signal and the pressure detection signal. For example, it is also possible to adopt a configuration in which both the input signal and the pressure detection signal are pulsated as in another electropneumatic regulator R4 shown in FIG.

The adder 76 constituting the pulsating means 74
Is a position different from that of the above embodiment or another example of FIGS. 5 and 6,
For example, it may be provided at point a (between the comparison circuits 70 and 71 and the output circuits 72 and 73) or point b (the output side of the output circuits 72 and 73) in FIG.

The oscillating circuit 75 as the oscillating means is not limited to the one that generates an oscillation signal of a plurality of waveforms as in the embodiment, but may be one that generates only an oscillation signal of one type of waveform. In the case where an oscillation signal having a plurality of types of waveforms can be generated, for example, a waveform mode selection switch for selecting a waveform may be provided in the control circuit 66.

The oscillation circuit 75 is not necessarily limited to the configuration using the two operational amplifiers 81 and 82, but may be configured using electronic components such as transistors.

A configuration in which the pulsating means is configured without using the oscillation circuit 75 may be employed. Here, in addition to the technical ideas described in the claims, technical ideas grasped by the above-described embodiments are listed below together with their effects.

(1) The electro-fluid pressure regulator according to any one of claims 2 to 4, wherein the oscillating circuit is configured using two operational amplifiers. With this configuration, it is possible to generate a plurality of types of oscillation signals.

(2) In the technical idea 1, the oscillating circuit can generate a plurality of kinds of oscillating signals, and the control means includes a selecting means for selecting the oscillating signals. Fluid pressure regulator. With this configuration, the waveform of the oscillation signal can be changed as needed.

(3) Claims 1 to 4, technical idea 1,
2. In any one of 2., the pair of valve elements provided in the internal flow path of the main valve portion may have a thrust obtained as a result of the pressure of the fluid flowing in the internal flow path acting on one end face side; An electro-hydraulic pressure regulator having a structure in which a thrust generated as a result of the pressure of the fluid acting on the other end face side cancels each other. With this configuration, the control accuracy can be further improved.

(4) Claims 1 to 4, technical idea 1,
2. In any one of the items 2, the slidably inserted through a first seal member through a first sleeve provided in an internal flow path of the main valve portion, and a valve top portion on one end surface thereof. A first valve body, a second valve body slidably inserted through a second seal member through a second sleeve provided in the internal flow path, and having a valve top on one end surface thereof; The two valve elements have a structure in which the thrust resulting from the pressure of the fluid acting on one end face and the thrust resulting from the pressure of the fluid acting on the other end face cancel each other. And a first valve provided at a position where a valve top of the first valve body can come and go in the internal flow path.
A valve seat member, a second valve seat member provided at a position at which the valve top of the second valve body can contact and separate in the internal flow path, and a feedback pressure fed back from the output port side to one end surface. A displacement transmitting body that has a pressure receiving body at one end thereof acting on the other end face and receiving a pilot pressure and displacing the two valve bodies by being displaced by a differential pressure acting on the pressure receiving body; A main valve portion having an urging means for urging the two valve bodies moving due to the displacement in a direction opposite to the moving direction thereof, and the two valve bodies abut on both the valve seat members so that the respective valve bodies are in contact with each other. The input port and the output port communicate with each other at a valve opening corresponding to the differential pressure by a neutral state in which the ports are shut off and only the first valve body is separated from the first valve seat member. Supply state and only the second valve body The electric-fluid pressure is switched to a discharge state in which the output port and the discharge port are communicated with a valve opening corresponding to the differential pressure by separating from the two-valve seat member. regulator. With this configuration, the control accuracy can be further improved.

The technical terms used in this specification are defined as follows. "Fluids: nitrogen, oxygen, carbon dioxide, argon, hydrogen,
In addition to a gas such as air, which is a mixture thereof, a liquid such as water or oil and others having properties similar thereto are included. "

[0080]

As described above in detail, according to the first to fourth aspects of the present invention, high control accuracy can be obtained even when the piston type is adopted as the pressure receiving member, and economical electric-fluid pressure can be obtained. A regulator can be provided.

According to the second aspect of the present invention, since the solenoid valve generates a pilot pressure that pulsates regularly and stably, higher control accuracy can be obtained. According to the third aspect of the present invention, it becomes easier to adjust the amplitude and frequency of the pulsation of the pilot pressure, so that higher control accuracy can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electropneumatic regulator according to a first embodiment.

FIG. 2 is a circuit diagram of an oscillation circuit in a control circuit of the electropneumatic regulator.

FIG. 3 is a schematic sectional view of the electropneumatic regulator.

FIG. 4 is a schematic sectional view of an electropneumatic regulator according to a second embodiment.

FIG. 5 is a block diagram showing another example of an electropneumatic regulator.

FIG. 6 is a block diagram showing another example of an electropneumatic regulator.

[Explanation of symbols]

1: Main valve section, 12: Input port, 13: Output port, 1
4 ... Discharge port, 63 ... Supply solenoid valve, 64 ... Discharge solenoid valve, 65 ... Pressure sensor as pressure detecting means, 66 ...
Control circuit as control means, 68 ... Differential amplifier circuit, 69
... input circuit, 70 ... first comparison circuit, 71 ... second comparison circuit, 72 ... first output circuit, 73 ... second output circuit,
74 pulsating means, 75 oscillating circuit forming pulsating means, 76 adders forming pulsating means, R1, R2,
R3, R4: electropneumatic regulator as an electric-fluid pressure regulator, P1: feedback pressure, P2: pilot fluid pressure.

Claims (4)

[Claims] 1. A main valve section for controlling communication between an input port, an output port and a discharge port, pressure detection means for converting a pressure of a pilot fluid into an electric signal and outputting the electric signal as a pressure detection signal, and Control means for outputting a solenoid valve drive signal generated based on a comparison result between the input signal input and the pressure detection signal; and controlling the pilot fluid by performing on / off control based on the solenoid valve drive signal. A supply solenoid valve and a discharge solenoid valve that output pressure, and perform proportional control of the main valve unit based on a differential pressure between a feedback pressure fed back from the output port side and a pressure of the pilot fluid. In the electro-fluid pressure regulator, both the supply solenoid valve and the discharge solenoid valve are two-way valves, and at least one of the input signal and the pressure detection signal is used. And a pulsating means for pulsating either of them is provided in the control means. 2. The pulsating means includes an oscillating circuit for generating an oscillating signal, and an adder for adding the oscillating signal to at least one of the input signal and the pressure detection signal. The electricity according to claim 1,
Fluid pressure regulator. 3. The signal according to claim 2, wherein the oscillation signal is added to at least one of the two signals before comparing the input signal with the pressure detection signal. Electric-fluid pressure regulator. 4. The control means includes a differential amplifier circuit for amplifying the pressure detection signal from the pressure detection means, and an input for converting an input signal from the external device into a state suitable for a comparison operation at a subsequent stage. Circuit, first and second comparison circuits that receive the converted input signal and the amplified pressure detection signal and compare the magnitudes thereof, and a comparison signal output from the first comparison circuit. A first output circuit that generates a first solenoid valve drive signal for controlling the supply solenoid valve to be turned on and off and outputs the signal to the supply solenoid valve, and a first output circuit that is output from the second comparison circuit. A second output circuit for generating a second solenoid valve drive signal for controlling the on / off of the discharge solenoid valve based on the comparison signal and outputting the signal to the discharge solenoid valve; Oscillation circuit to generate and its oscillation signal And an adder for adding the converted input signal and / or the amplified pressure detection signal to a stage immediately before the comparison circuit. An electro-fluid pressure regulator as described.