JPH01108483A - Pneumatic equipment - Google Patents

Abstract

PURPOSE:To eliminate the pulsation of output air pressure and enhance responsiveness by connecting the output port of the first directional control valve to by the second directional control valve directly or through a throttle. CONSTITUTION:The first directional control valve 41 makes the output port 12 communicating with a pneumatically operated section 2 communicate with either a supply orifice 10 communicating with a pressured air source or an exhaust air orifice 11 with the two switched to each other by means of an electrostriction element 13 distorting itself according to input electrical signals. The second directional control valve 42 communicates with the pneumatically operated section 2 after a lapse of specified time directly to switch the output port 12 to the communication position through a throttle 46. The pulsation of air pressure can, therefore, be eliminated by the throttle. The shortening of the time that air pressure reaches a specified pressure can enhance the responsiveness of an equipment.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to pneumatic equipment that operates with an output pneumatic pressure proportional to an input electrical signal.

[Conventional technology]

The inventors of the present invention have provided an electro-pneumatic conversion section that converts an input electrical signal into pneumatic pressure proportional to the electrical signal and outputs the same, and a pneumatic operation section that operates based on the signal air pressure, and has provided an electric power to the electro-pneumatic conversion section. Pneumatic equipment using a directional control valve having a strain element was proposed in Utility Model Application No. 112939/1983 and others.

The pneumatic equipment described above includes, for example, as shown in FIG. 7, an electro-pneumatic conversion section 1 and a pneumatic positioner 2, which is an example of a pneumatic operation section.

The electro-pneumatic converter 1 includes a controller 4 to which a signal current is input, a directional switching valve 5 using an electrostrictive element. A signal air line 6 transmits the signal air pressure output from the directional control valve 5 to the pneumatic positioner, and a controller 4 converts the signal air pressure of the signal air line 6 into a feedback electric signal.
The controller 4 compares the magnitude of the input electric signal and the feedback electric signal and applies a control voltage to the electrostrictive element 13 of the directional control valve 5.

The valve body 9 of the directional valve 5 has a supply orifice 10. which communicates with a source of pressurized air. It has an exhaust orifice 11 communicating with the outside and an outlet capo 12 communicating with the air pipe line 6,
A valve member 14.14 for opening and closing the orifice 10.11 is attached to the free end of the electrostrictive element 13, which is distorted by a control voltage applied from the controller 4. The electrostrictive element 13 is a bimorph type electrostrictive element made by laminating plate-shaped piezoelectric ceramics on both sides of an electrode that expand and contract depending on the polarity of applied voltage, and when a voltage of a predetermined polarity is applied. When it is distorted in one direction and a voltage of the opposite polarity is applied or the application of the voltage is removed, it is distorted in the opposite direction or returns to its original state.

The pneumatic positioner 2 has a pressure input diaphragm 17 that is displaced by a signal air pressure input from a signal air pipe line 6.
, a nozzle flapper mechanism 20 consisting of a flapper 18 that swings as the diaphragm 17 is displaced, and a nozzle 19 that opens opposite the flapper 18; a back pressure diaphragm 21 that is displaced as the back pressure of the nozzle 19 rises and falls; A valve rod 22 that is displaced together with the back pressure diaphragm 21, and a valve body 24 that connects the communication path between the pressurized air supply port P and the output port A depending on the displacement of the valve rod 22 and the biasing force of the return spring 23. ．． An air pipe line 2B that connects the output port A and the diaphragm valve 25, and the diaphragm valve 2
5 is fed back to the input pressure diaphragm 17, and the feedback mechanism 27 includes a feed/hook lever 31, M 32. which is rotated by a valve lever 30 that is driven integrally with the diaphragm valve 25. Transmission arm 33 and /<-3
4, and a feedback spring 35 is provided between the lever 34 and the pressure diaphragm 17. Reference numeral 37 in FIG. 7 is a throttle provided in the signal air conduit 6, which eliminates pressure fluctuations (pulsations) caused by the operation of the directional valve 5 and makes the signal air pressure analogous.

In the pneumatic equipment, when a signal current is input to the controller 4, the controller 4 compares the input electric signal with a feedback electric signal obtained by converting the signal air pressure fed back from the pressure sensor 7, and generates a feedback electric signal. is smaller than the input electrical signal, the controller 4 applies a control voltage to the electrostrictive element 13 with a polarity that distorts the supply orifice 10 to open and the exhaust orifice 11 to close. is supplied to the signal air conduit 6 through the output port 12 to increase the signal air pressure, and as a result, when the feedback electric signal becomes larger than the input electric signal, the controller 4 causes the electrostrictive element 13 to perform the above-described operation. By applying a control voltage of opposite polarity or by canceling the application of the above voltage, the electrostrictive element 13
The supply orifice lO is closed and the exhaust orifice 11 is returned to the direction of opening, so that the signal air pressure in the signal air line 6 decreases, the feedback electric signal becomes smaller than the input electric signal, and the electric signal is sent to the controller 4. While the input is being input, the directional switching valve 5 repeats the above-described operation.

In this case, by performing the opening/closing operation frequently, an analog signal air pressure proportional to the input electrical signal is output from the output port 12.

In the pneumatic positioner 2, when the pressure input diaphragm 17 and the nozzle flapper mechanism 20 are in an equilibrium state, when the signal air pressure in the signal air conduit 6 increases due to an input electrical signal, the pressure input diaphragm 17 moves to the left in the figure. As the flapper 18 is displaced and swings, the nozzle 19 opens and its back pressure decreases, so the back pressure diaphragm 21 and valve #522, which are in communication with the pressure air source, move to the right in the figure, and the valve body 24 The supply port P and the output port At are connected in series.

Therefore, pressurized air is supplied to the diaphragm valve 25 through the air line 26 to drive the valve 25, and the drive of the valve 25 is fed back to the pressure input diaphragm 17 by the feedback mechanism 27. In this way, when the force that the feedback spring 35 acts on the input diaphragm 17 becomes equal to the force that the @ air pressure acts on the input diaphragm 17, a new equilibrium state is established, and the input diaphragm 17 and nozzle flapper mechanism 2
0 is stable.

In the pneumatic equipment proposed above, if no throttle is installed in the signal air conduit 6, some pulsation remains in the signal air pressure when the input electric signal is applied stepwise (see Fig. 8).
Although the magnitude of this pulsation can be made very small by designing each constant to an optimal value, it is technically difficult to completely eliminate it. However, when this pneumatic equipment is used in a signal system or the like, it is necessary to completely eliminate pulsation.

In this case, by installing a throttle 37 in the signal air pipe line 6, the pulsation of the signal air pressure can be completely eliminated, but the throttle increases the time t1 for the signal air pressure to reach a predetermined pressure (Fig. 9). In other words, a new problem arises in that the responsiveness of the pneumatic equipment decreases.

[Problems to be Solved by the Invention] The present invention provides electro-pneumatic conversion by providing a second directional valve that communicates the output port of the first directional valve with the pneumatic operating section directly or through a restriction. The problem to be solved is to improve the responsiveness of the air pressure while eliminating the pulsations in the air pressure output from the air pressure section.

[Means for Solving the Problems] The present invention provides a pneumatic device comprising an electro-pneumatic converter that converts an input electrical signal into pneumatic pressure proportional to the input electrical signal and outputs the pneumatic converter, and a pneumatic operating section that operates based on the pneumatic pressure. wherein the electro-pneumatic conversion section has a supply orifice communicating with a source of pressurized air, an exhaust orifice communicating with the outside, an output port communicating with the pneumatic operating section, and distorting the input electrical signal in response to the input electrical signal; a first directional control valve having an electrostrictive element that switches and communicates with one of the two orifices; and after a predetermined period of time, the output directly communicates with the pneumatic operating section in response to the input electric signal. The above problem is solved by providing a second directional control valve that switches the port to a position where it communicates with the port via the throttle.

[Function] When an input electric signal is input, the supply orifice is opened and the exhaust orifice is closed by the electrostrictive element which distorts in response to the input electric signal, so that the first directional control valve generates a signal proportional to the input electric signal. Pneumatic pressure is output, and the pneumatic operating section is operated by this pneumatic pressure.

Initially, the air pressure is directly communicated with the pneumatic operating section, so the air pressure of the pneumatic operating section quickly increases. After a predetermined period of time has elapsed, the second directional control valve is switched to a position where it communicates with the pneumatic operating section via the throttle, so that the throttle can eliminate air pressure pulsations. Furthermore, since the time required for the air pressure to reach a predetermined pressure is shortened, the responsiveness of the device can be improved.

[Embodiment] FIG. 1 shows a first embodiment of the present invention, in which a signal air is used to communicate the output port 12 of the first directional control valve 41 having the electrostrictive element 13 with the pneumatic positioner 2. A second directional control valve 42 is provided in the conduit 6 in place of the throttle 37. Since the other configuration of the first embodiment is the same as the previously proposed pneumatic equipment shown in FIG. 7, the same reference numerals are given in the figure and detailed explanation will be omitted.

The second directional control valve 42 has an inlet port 43 that communicates with the output port 12 and a first directional control valve that communicates directly with the signal air line 6.
An output port 44 and a second output port 45 are provided, and the second output port 45 is connected to the signal air pipe line 6 through a restriction 46.
The solenoid 42a of the switching valve 42 is electrically connected to the controller 4 via a delay circuit 47.

The delay circuit 47 controls the solenoid 4 when the signal air pressure, which increases due to the application of voltage to the electrostrictive element 13, reaches about 50 to 97%, preferably 90 to 95%, of the output pressure.
2a, and when the solenoid 42a is excited, the inlet port 43 communicating with the first outlet port 44
is communicated with the second output port 45, and the signal air pressure is transmitted to the air pressure operating section 2 via the throttle 46.

Therefore, before the delay time elapses, the responsiveness of the device can be improved by directly transmitting the signal air pressure to the pneumatic operating unit 2 and shortening the time t2 for the signal air pressure to reach a predetermined pressure, and the delay time After the elapse of , the pulsation of the signal air pressure can be completely eliminated by transmitting the signal air pressure to the air pressure operating section via the throttle 46 (see FIG. 2).

When the input electric signal is released, the second directional switching valve 42 returns to the position where the inlet port 43 and the first outlet port 44 communicate with each other by the biasing force of the return spring.

The other operations of the first embodiment are the same as those of the pneumatic equipment shown in FIG. 7, so a detailed explanation will be omitted.

FIG. 3 shows the second directional control valve 50 connected to a solenoid 50a.
The inlet port 51 and the outlet port 5 are de-energized and energized.
The signal air pipe line 6 is equipped with a throttle 54 in a bypass 53 connected in parallel with the second directional control valve 50.

In the above-mentioned directional control valve, when the solenoid 50a is de-energized, the output port 12 of the first directional control valve 41 communicates with the signal air line 6 through the directional control valve 50 and the bypass 54, and the solenoid 50a is energized. Then, communication is established through a bypass 53 having an aperture 54.

FIG. 4 shows the second directional valve 60 connected to the inlet orifice 6.
1. Outlet port 62. Another modification example is shown in which the inlet orifice 61 is opened and closed by the application and removal of voltage. It is equipped with an aperture 65.

In the directional switching valve, when no control voltage is applied to the electrostrictive element 63, the inlet orifice 61 and the outlet boat 62 communicate with each other, and when the control pressure is applied via the delay circuit 47,
Electrostrictive element 63 is distorted and closes inlet orifice 61 .

FIG. 5 shows a second embodiment of the present invention in which the pneumatic operation section is a control valve 70 having a feedback mechanism to the electropneumatic conversion section 69, and the controller 4. First directional valve 41 and second directional valve 42
Since it has the same configuration as the first embodiment, the same reference numerals are given in each figure, and detailed explanation will be omitted. Note that the second directional switching valve may be the directional switching valve 50, 60 shown in FIGS. 3 and 4.

The feedback mechanism 71 in the control valve 70 includes a feedback lever 73 that is rotated by a valve lever 72 that is driven integrally with the control valve 70, a support shaft 74, and a feedback cam 75. Also, a cantilever 76 which is bent by the pressure of the feedback cam 75, a displacement sensor 77 attached to the cantilever 76, which converts the displacement of the cantilever 76 into an electric signal proportional to it and outputs it, and a feedback electric signal outputted from the displacement sensor 77. The feedback cam 75 includes a feedback circuit 78 that provides feedback to the controller 4, and the feedback cam 75 has a cam surface whose distance from the support shaft increases as it rotates clockwise in the figure.

Therefore, by applying the control voltage to the electrostrictive element 13,
When the control valve 70 is driven by the output air pressure from the first directional control valve 4, the pulse brake half 2 moves downward as shown in the figure, and the feed valve half /<-73, the support shaft 74
Then, the feedback cam 75 is rotated clockwise in the figure, and the roll 79 at the tip of the cantilever is pressed by the cam 75 and the cantilever 76 is displaced.
A displacement sensor 77 on 6 converts this displacement into a proportional feedback electrical signal and feeds it back to controller 4.

Second directional control valve 42 or 5 in the second embodiment
Since the effect of 0.60 is as described above, detailed explanation will be omitted.

FIG. 6 shows the first directional control valve 80 as a second direction switching valve using an electrostrictive element.
A modification is shown in which two on-off valves 81 and 82 are used, and the common valve body in this directional switching valve 80 is valve chambers 83a and 83b.
, the valve chamber 83a has a supply orifice 10 communicating with a source of pressurized air and a boat 84 communicating with an air line 88;
A valve member 14 that opens and closes the supply orifice 10 is attached to the free end of the electrostrictive element 85 that is distorted by a control voltage applied from the controller 4 . On the other hand, the valve chamber 83b
The exhaust orifice 11 and the air pipe 88 communicate with the outside.
A valve member 14 for opening and closing the exhaust orifice 11 is attached to the free end of an electrostrictive element 87 that is distorted by a control voltage applied from the controller 4. 85 and 87 have the same configuration as the electrostrictive element 13.

Although not shown, the air pipe line 88 is provided with the above-mentioned second directional control valve 42 or 50.60.

The directional switching valve 80 is configured such that when the feedback electric signal is smaller than the input electric signal, the controller 4 opens the supply orifice 10 to the electrostrictive element 85 and the direction in which the exhaust orifice 11 is closed to the electrostrictive element 87. Since the polarity II control voltages are respectively applied to cause distortion, pressurized air from the pressure air source is supplied from the boat 84 to the air pipe line 8, and the air pressure rises in an analog manner. As a result, when the feedback electric signal becomes larger than the input electric signal, the controller 4 applies a control voltage with the opposite polarity to the electrostrictive elements 85 and 87, or cancels the application of the voltage to the electrostrictive elements 85 and 87. Since the electrostrictive element 87 is returned to the direction of closing the supply orifice 10 and the direction of opening the exhaust orifice +1, the air pressure decreases in an analog manner.

In this case, when the input electrical signal is constant and the input electrical signal and the feedback electrical signal are equal, there is no air consumption in the electrical pressure operating part, so it is closed together with the supply and exhaust orifices to eliminate wasteful air consumption. Can be done.

Although not shown, the first directional control valve 41.
80 and the second directional control valve 42, 50, 60 can be integrated into a compact structure. Further, the pneumatic operating section can also be configured in other ways, such as a booster relay.

[Effects of the Invention] The pneumatic equipment of the present invention is provided with a second directional control valve that switches the output port of the first directional control valve between a position in which it communicates directly with the pneumatic operating section and a position in which it communicates through a throttle. In addition, since the directional control valve is directly communicated with the pneumatic operating section, and after a predetermined period of time has elapsed, the directional control valve is communicated via the throttle by an input electric signal, so that pulsation of the signal pneumatic pressure from the electro-pneumatic conversion section can be eliminated. It is possible to improve the responsiveness of a single device.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of the first embodiment of the present invention, FIG. 2 is an example of waveforms of the input electrical signal and output air pressure, and FIGS. 3 and 4 are modifications of the second directional control valve. A schematic configuration diagram of
FIG. 5 is a schematic diagram of the second embodiment of the present invention, FIG. 6 is a schematic diagram of a modification of the first directional valve, FIG. 7 is a schematic diagram of the previously proposed pneumatic equipment, and FIG. FIG. 9 and FIG. 9 are examples of the waveforms of the input electrification signal and the signal air pressure in the case without the throttle and in the case with the throttle. 1.63...Electro-pneumatic conversion section. 2. Pneumatic positioner, 1011. Supply orifice, 11. Exhaust orifice, 12. Output port. 13.63, 85.87 ・・Electrostrictive element, 41.80
...First directional switching valve, 42.50,60...Second directional switching valve, 46.54,
65. Fist squeeze, 70. Control valve. Patent applicant: Nissmc Co., Ltd. (1 other person) - 2rlA and 3rd ean

Claims (1)

[Scope of Claims] 1. A pneumatic device comprising an electro-pneumatic converter that converts an input electrical signal into pneumatic pressure proportional to the input electrical signal and outputs the pneumatic converter, and a pneumatic operating section that operates based on the pneumatic pressure, the electro-pneumatic converter as described above. a supply orifice in communication with a source of pressurized air, an exhaust orifice in communication with the outside, an output port in communication with the pneumatic actuator, and a portion correspondingly distorting the input electrical signal to direct the output port to one of the two orifices. A first directional control valve having an electrostrictive element that is switched to communicate with the output port, which is in direct communication with the pneumatic operating section, communicates with the output port that directly communicates with the pneumatic operating section after a predetermined time has elapsed by the input electric signal. A pneumatic device, comprising: a second directional control valve that switches between positions.