JPH0633903A - Reciprocal actuator and its control method - Google Patents

Abstract

PURPOSE:To provide a reciprocating actuator which is preferable in explosion proof and capable of easily variable control of the moving stroke of a piston, the moving speed of the moving stroke or the like. CONSTITUTION:A piston 13 is provided in a vertically movable manner within a cylinder 12 of an actuator body 11. An AC generator 31 which is driven by converting the vertical movement of the piston 13 into the rotation by a female screw member 43 and a screw 42 is provided on the upper side of the actuator body 11. A built-in battery to be charged by the generator 31 and an electronic control part 49 are provided on one side of the actuator body 11, while a working fluid control valve 21 which executes the directional control and the flow rate control of the piston working fluid is provided on the other side. When the piston 13 is moved in the vertical direction, the generator 31 is rotated to charge the battery, and to operate the electronic control part 49 and the working fluid control valve 21. The AC signal outputted from the AC generator 31 is made use of as the action detecting information by the electronic control part 49. When the working fluid control valve 21 is controlled while counting the AC signal, the moving stroke and the moving speed of the piston 13 can be controlled as aimed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reciprocating actuator for driving a pump or the like and a control method thereof.

[0002]

2. Description of the Related Art As disclosed in JP-B-48-21964 (piston type actuator) or JP-B-42-23303 (diaphragm pump), a working rod for driving a pump is reciprocally driven by working fluid pressure. The moved reciprocating actuator has a working fluid switching mechanism that is switched at its stroke end in conjunction with the movement of the working rod.

[0003]

In the working fluid switching mechanism of the working rod interlocking type, even if it is necessary to change the working stroke of a metering pump or the working speed of a high-viscosity pump, it is easy to do so. I can't.

When switching the working fluid of a reciprocating actuator by means of a solenoid valve or when trying to control the operation of the actuator by a rotary encoder, the pump operated by this actuator uses a combustible fluid such as gasoline. In consideration of handling, it is necessary to surely perform explosion-proof treatment in connection with an external power source such as a battery installed outside, but reliable explosion-proof treatment to the external power source is not easy.

Further, as shown in FIG. 6, by driving the two pumps so that the pulsating phases of the two pumps are deviated from each other as shown in FIG. 6, it is conventional to reduce the ripple of the combined discharge pressure of the pumps. However, the conventional actuator control method that only shifts the pulsating phase has a limit in reducing the ripple.

The present invention has been made in view of the above points, and an object thereof is to provide a reciprocating actuator which is advantageous in explosion proof and which can easily and variably control the moving stroke and moving speed of the operating rod. Another object of the present invention is to provide a method of controlling a reciprocating actuator that is effective when reducing ripples at the combined discharge pressure of two pumps.

[0007]

According to a first aspect of the present invention, there is provided a reciprocating actuator which is driven by working fluid pressure to reciprocate the working rod, and a generator driven by movement of the working rod. A reciprocating actuator having an electronic control unit that processes the operation detection information output from the generator and a working fluid control valve that controls the working fluid based on a control signal output from the electronic control unit. .

According to a second aspect of the present invention, an electronic control system is enclosed in a fluid drive system, and self-power generation also functions as an operation detection function in conjunction with an operation rod of the fluid drive system to implement flexible control. Is performed to supply energy and motion detection information to the electronic control system, and the fluid drive system is controlled by the electronic control system.

According to a third aspect of the present invention, there is provided a method of controlling a pair of reciprocating actuators, which drives a pair of pumps having a common discharge port by reciprocating an operating rod by driving with working fluid pressure. Displacement of one pump driven by one reciprocating actuator by mutually exchanging motion detection information output from the generator driven by the movement of each operating rod between a pair of reciprocating actuators. A control method of a reciprocating actuator that mutually controls the working fluid control valves of the respective actuators so that the other pump discharge pressure driven by the other reciprocating actuator increases when the reciprocating motion is reduced. Is.

[0010]

According to the first aspect of the invention, the generator is driven by the operating rod of the reciprocating actuator, and the working fluid control valve is controlled by the electronic control unit based on the operation detection information output from the generator. Then, the stop position, moving stroke, and moving speed of the operating rod are controlled as desired.

According to a second aspect of the present invention, an electronic control system integrated with the fluid drive system itself is provided by allowing the fluid drive system to perform self-power generation by the fluid energy without being supplied with electric energy from the outside. It gives electric energy and motion detection information and controls its own motion.

According to a third aspect of the present invention, the motion detection information output from the generator is mutually exchanged between a pair of reciprocating actuators, and one of the reciprocating actuators drives the other. When switching between reciprocating motions where the pump discharge pressure drops, the other pump discharge pressure driven by the other reciprocating actuator is controlled so as to increase each other, thereby canceling the ripple of the pump discharge pressure. To do.

[0013]

The present invention will be described below in detail with reference to the embodiments shown in the drawings.

1 and 2 show an example of a piston type reciprocating actuator which is driven by working fluid pressure (pneumatic pressure) to reciprocate, and a cylinder 12 is screwed to a lower portion of an actuator body 11. A piston 13 is slidably fitted inside the cylinder 12, and an operating rod 14 integrated with the piston 13 passes through a seal member 16 between a cylinder end member 15 fitted in a lower opening of the cylinder 12. It projects downward and is connected to the shaft of a reciprocating pump (not shown).

A working fluid control valve 21 is attached to one side surface of the actuator body 11, and one output port of the working fluid control valve 21 is an inner hole 22, 23 of the actuator body 11.
Through the working fluid chamber 24 above the piston 13,
Further, the other output port of the working fluid control valve 21 is communicated with the working fluid chamber 27 below the piston 13 via the outer pipe 25 and the inner hole 26 of the cylinder end member 15, and from this working fluid control valve 21. The working fluid is alternately supplied to and discharged from both working fluid chambers 24 and 27.

An AC generator 31 is integrally provided on the upper side of the actuator body 11. That is, the generator body 32 is screwed to the actuator body 11, the fixed armature (coil) 34 is attached to the generator body 32 by the mounting plate 33, and the concentric fixed shaft 35 under the fixed armature 34. A rotor (multi-divided magnet) 37 having a fixed gap with the fixed armature 34 is rotatably mounted by a pair of bearings 36 fitted in the.

A screw 42 is concentrically and integrally attached to the rotor 37 via a connecting portion 41.
Is screwed into a female screw member 43 integrally fitted to the central portion of the piston 13 and fitted into an inner hole 44 of the operating rod 14. Since the screw 42 has a large lead (pitch) of the screw thread, when the operating rod 14 which is prevented from rotating by the guide means (not shown) moves linearly, the operating rod 14
It is easily rotated by the screwing relationship with the female screw member 43 integrated with the.

Further, an electric equipment portion 48 is provided in the concave groove 47 provided on the outer peripheral surface of the actuator body 11, and inside thereof, an internal battery charged by the generator 31 and
A central processing unit (C which processes the operation detection information (sine wave signal) output from the generator 31 to control the operation of the control valve 21 (C
An electronic control unit 49 including a circuit including a PU) and peripheral controllers is provided.

As shown in FIG. 2, the working fluid control valve 21 is a 4-port switching valve for controlling the piston working fluid based on the operation detection information output from the generator 31, and is provided inside the valve body 51. A spool 53 is slidably fitted inside the fitted sleeve 52, and the spool 53 is pressed against a stopper 55 on the other side by a compression coil spring 54 provided on one side. A pilot valve 57, which outputs an air pressure proportional to an electric signal input, such as an electric-pneumatic proportional valve (servo valve), is provided to the pilot pressure chamber 56 provided in. A stopper 58 also serving as a spring receiver is provided on the spring side.

The valve body 51 is provided with an input port 61 for working fluid, two output ports 62 and 63, and a discharge pressure port 64. The input port 61 is also communicated with the input port 61a on the left side of the sleeve via the branched passage 65, and one output port 62 is connected to the working fluid chamber 24 above the piston 13 via the inner holes 22 and 23. Connected to the other output port
63 communicates with the working fluid chamber 27 below the piston 13 via the passage 66 and the external pipe 25, and further, the exhaust pressure port 64
Is open to the outside and serves as an exhaust port.

When the spool 53 is at the solid line position, the input port 61 is communicated with the output port 62 through the sleeve 52, and the output port 63 is passed through the sleeve and the exhaust pressure port.
It is connected to 64. When the spool 53 is switched to the alternate long and two short dashes position, the input port 61a is communicated with the output port 63 through the sleeve, and the output port 62 is communicated with the exhaust pressure port 64 through the sleeve.

The pilot valve 57 does not simply switch the spool 53 between the solid line position and the two-dot chain line position as described above due to the relative relationship between the pneumatic output and the compression coil spring 54. However, the input ports 61 and 61a can be controlled proportionally to any position between the two positions.
Through sleeve 52 to one output port 62 (or 6
3) Working fluid supplied to the other output port 63
The working fluid discharged from (or 62) through the sleeve to the exhaust pressure port 64 can be throttled to an arbitrary flow rate by the spool 53, and the moving speed of the piston 13 can be changed. Further, the pilot valve 57 is connected to the spool 53 in relation to the moving position of the piston 13 of the reciprocating actuator.
It is also possible to control the stop position and the movement stroke of the piston 13 by controlling the operation timing of.

When the pilot pressure supplied to and discharged from the pilot valve 57 to the pilot chamber 56 of the working fluid control valve 21 is controlled to be turned on and off at a constant cycle, and the spool 53 is controlled to switch between the two positions, a reciprocating motion occurs. The piston 13 and the operating rod 14 of the dynamic actuator are moved up and down in that cycle, and the reciprocating pump and the like connected to the operating rod 14 are driven. At this time, the screw 42, which is screwed into the female screw member 43 that is moved integrally with the operating rod 14, rotates, and the rotor (magnet) 37 of the AC generator 31 also rotates. ) 34, an AC output is obtained, so that this AC output is rectified by a rectifier circuit (not shown) to charge the built-in battery, and this battery drives the pilot valve 57 and its control circuit (including the CPU).

Further, the piston 13 and the operating rod
The AC waveform (sine wave) output from the generator 31 in proportion to the movement amount of 14 is also treated as operation detection information, and the number of waves is counted by a counting circuit. For example, the total number from the reciprocating switching position (stop position) is counted. By counting the wave number, the moving stroke of the piston 13 can be detected, and the moving speed of the piston 13 and the working rod 14 can be detected from the wave number per unit time.

Therefore, if the pilot valve 57 of the working fluid control valve 21 is controlled by the electronic control section 49 provided in the electric component section 48 based on these operation detection data,
The stop position, moving stroke and moving speed of the piston 13 can be controlled as desired. The control of the piston movement stroke can correspond to the change of the discharge amount in the metering pump etc.
The control of the piston moving speed can cope with the viscosity change of the pump material in a high viscosity pump or the like.

FIG. 3 shows an embodiment in which the reciprocating actuator of the present invention is integrally incorporated in a diaphragm pump, and a pair of left and right working fluid chambers 24 and 27 and left and right pump chambers 71 and 72 are partitioned. The diaphragms 73 and 74 are connected by the operating rod 14, and an AC generator 31 driven by the movement of the operating rod 14 is provided between the left and right working fluid chambers 24 and 27.

In the generator 31, a screw 42 integrally formed with the operating rod 14 and a female screw portion 43 whose axial movement is restricted by a pair of thrust bearings 36 are screwed together.
A rotor (multi-divided magnet) 37 is integrally provided on the female screw portion 43, and a fixed armature (coil) 34 is provided facing the rotor 37.

Further, on the outer peripheral portion of the generator 31, there is an electric component section 48 in which an internal battery charged by the generator 31 and an electronic control section 49 including a central processing unit (CPU) and a peripheral controller are incorporated. , And a working fluid control valve 21. The working fluid control valve 21 integrally includes an electric-pneumatic proportional pilot valve 57 (not shown in FIG. 3) shown in FIG. 2, and as in the case of FIG. Based on the operation detection information (sinusoidal wave signal) output from, the working fluid (air) is controlled to be supplied to and discharged from the left and right working fluid chambers 24 and 27 via the pipes 22 and 25.

In this diaphragm pump, when the left and right working fluid chambers 24 and 27 repeatedly expand and contract by alternately supplying and discharging the working fluid, the left and right pump chambers 71 and 72 alternately change their volumes and repeat expansion and contraction. Therefore, the pump material is sucked from the pump material suction port 75 through the lower check valve 76, and the pump material is pushed out to the discharge port 78 through the upper check valve 77.

Like the piston type actuator shown in FIGS. 1 and 2, this diaphragm type actuator also charges the built-in battery by the generator 31 driven by the movement of the operating rod 14, and the battery controls the electronic control unit. 49 and the pilot valve of the working fluid control valve 21 are supplied with electric power, and the sine wave signal output from the generator 31 is synchronized with the movement of the working rod 14 to count the moving position and moving speed of the working rod 14. Is detected and the pilot valve of the working fluid control valve 21 is controlled based on the operation detection information, thereby controlling the stop position, moving stroke and moving speed of the reciprocating working rod 14 as desired.

FIG. 4 shows a pair of reciprocating pumps for driving the pump material discharge ports 78 of the pair of pumps A and B (piston pump, diaphragm pump, etc.) when they are connected to form a common discharge port 79. FIG. 3 is a schematic diagram showing an example of intelligent pump control in which information is mutually exchanged between dynamic actuators for control, and the above-described operation output from a generator 31 driven by movement of an operating rod 14 of each actuator. Detection information (moving position, moving speed, etc.)
Is processed by an electronic control unit 49 including the CPU and peripheral controller, and then converted into an analog control signal to operate the working fluid control valve 21 (electric-
The air pressure proportional pilot valves 57) are mutually provided to perform the following control.

For example, as shown in FIG. 5, at the time of reciprocation switching t1 when the discharge pressure P1 of one pump driven by one reciprocating actuator drops, it is driven by the other reciprocating actuator. It is driven by one reciprocating actuator at the time of reciprocation switching t2 when the other pump discharge pressure P2 increases and the other pump's discharge pressure P2 is driven by the other reciprocating actuator. Control valve 21 (pilot valve 5) of each actuator so that pump discharge pressure P1 increases.
By mutually controlling the direction and the flow rate of 7), the ripple of the pump discharge pressure can be canceled at the pump discharge port 79 where the two pump material discharge ports 78 are merged, and even the reciprocating pump can be smoothed. The pump discharge pressure can be obtained.

FIG. 6 is a diagram showing a pump discharge pressure waveform in the case where a pair of conventional pumps are used in combination. The discharge pressure P1 of one pump drops at the time of reciprocating switching t1 and the discharge pressure of the other pump. By shifting t2 when reciprocating when P2 drops,
It is possible to reduce, but not cancel, the ripple of pump discharge pressure at the combined discharge ports of the two reciprocating pumps.

The generator 31 is of a rotary type, but a linear type generator (in which the input and output of a linear motor are reversed) may be directly connected to the piston 13 and the working rod 14. .

Further, since the smoothing capacitor for rectifying the AC output from the generator 31 may have a function corresponding to the battery in some cases, the battery is not necessary.

[0036]

According to the first aspect of the invention, the electronic control unit controls the working fluid control valve based on the motion detection information output from the generator driven by the working rod of the reciprocating actuator. Therefore, flexible reciprocating motion control can be implemented. That is, the stop position, moving stroke, moving speed, etc. of the operating rod can be easily variably controlled as necessary, and for example, the moving stroke can be variably controlled to easily cope with a change in the discharge amount of the metering pump.
The moving speed can be variably controlled to easily cope with the viscosity change of the pump material in the high viscosity pump.

According to the second aspect of the present invention, the electronic control system is enclosed in the fluid drive system, and the electronic control system is controlled by the self-power generation interlocking with the fluid-driven actuating rod. The flexible control can be performed, and the explosion-proof treatment can be performed easily and surely as a drive actuator for a pump that handles a flammable fluid, as compared with an actuator that is supplied with electric power from an external power source.

According to the third aspect of the present invention, the motion detection information output from the generator is mutually exchanged between the pair of reciprocating actuators and driven by one reciprocating actuator. When switching the reciprocating motion in which the discharge pressure of one pump drops, the other pump drive pressure driven by the other reciprocating actuator is controlled so as to increase each other. The pair of reciprocating actuators can be controlled so as to cancel out and obtain a smooth combined discharge pressure with less pulsation.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a reciprocating actuator of the present invention.

FIG. 2 is a sectional view of a working fluid control valve of the same actuator.

FIG. 3 is a sectional view showing another embodiment of the reciprocating actuator of the present invention.

FIG. 4 is a block diagram showing a control method when a pair of reciprocating actuators of the present invention is provided.

5 is a diagram showing a pump discharge pressure waveform in the embodiment of FIG.

FIG. 6 is a diagram showing a conventional pump discharge pressure waveform.

[Explanation of symbols]

 14 Working rod 21 Working fluid control valve 31 Generator 49 Electronic control unit 79 Common discharge port A, B A pair of pumps

Claims (3)

[Claims] 1. A reciprocating actuator in which a working rod is reciprocated by being driven by a working fluid pressure, and a generator driven by the movement of the working rod, and motion detection information output from the generator. And a working fluid control valve that controls working fluid based on a control signal output from the electronic control unit. 2. An electronic control system is enclosed in a fluid drive system, and self-power generation that also functions as an operation detection function is performed in conjunction with an operation rod of the fluid drive system to implement flexible control. A method of controlling a reciprocating actuator, characterized in that energy and motion detection information are supplied and a fluid drive system is controlled by the electronic control system. 3. A method of controlling a pair of reciprocating actuators, which drives a pair of pumps having a common discharge port by reciprocating an operating rod by driving with a working fluid pressure, comprising: Reciprocal motion switching in which the discharge pressure of one pump driven by one reciprocating actuator is dropped by mutually exchanging information on the motion detection information output from the generator driven by the movement of each operating rod. A method for controlling a reciprocating actuator, wherein the working fluid control valves of the respective actuators are mutually controlled so that the pump discharge pressure of the other pump driven by the other reciprocating actuator is increased.