JPS62255675A - Electromagnetic proportional valve control device - Google Patents

Abstract

PURPOSE:To obtain accurate proportional control by setting the rectangular voltage frequency to a predetermined small value, when average voltage applied is small, and increasing the rectangular voltage frequency, when the average voltage applied is large. CONSTITUTION:When a rectangular signal indicating a relatively small opening degree is transmitted from opening degree indicating means 1 to rectangular signal generating means, a reference oscillation frequency signal 11 is transmitted from oscillating means 10 to the rectangular signal generating means, and in a vibrating condition, a valve member is moved to a position corresponding to the indicated opening degree. When a rectangular signal indicating a relatively large opening degree is transmitted from the opening degree indicating means 1 to the rectangular signal generating means, frequency increasing means is actuated to increase the oscillation frequency of the oscillating means 10 in correspondence to the opening degree indicating signal 1, permitting movement with vibration restricted.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an electromagnetic proportional valve control device, and more particularly, to an electromagnetic proportional valve control device that drives an electromagnetic proportional valve with good resolution and hysteresis characteristics.

<Prior art> Conventionally, in order to control the operation of an electromagnetic proportional valve that moves a valve body in proportion to the current value to perform proportional control of fluid flow rate and proportional pressure control, a method as shown in Fig. 6 has been used. Like, 'II
gTooth wave generation circuit (generates a square wave by supplying the sawtooth wave output from the switching circuit (32) to a switching circuit (32), amplifies it to a predetermined level with a transistor amplifier (33), and generates a rectangular wave from the electromagnetic proportional valve. The switching transistor (35) that controls the energization to the wired (34) is set to 0N-O.
An electromagnetic proportional valve νJutl device which is configured to be FF is provided. In addition, a surge absorption circuit consisting of a resistor (36) and a reversely connected diode (37) connected in series is connected in parallel with the above-mentioned Tsulade (34).
(See Publication No. 28018).

Therefore, the state is equivalent to that when the average voltage signal determined by the 0N-OFF time ratio of the above rectangular wave is supplied to the solenoid (34), so the valve body is adjusted so that the opening degree corresponds to the above average voltage. Drive and proportional control of fluid flow 'aρ
, pressure proportional control can be performed.

In addition, when performing the above operation, the frequency of the rectangular wave signal applied to the solenoid (34) is determined in advance, and the frequency of the rectangular wave signal applied to the solenoid (34) is determined in advance at a predetermined rate every cycle determined by this frequency. Voltage is 0N-OFF
As this is repeated, the valve body continues to vibrate in a minute range,
In the electromagnetic proportional valve control 211 device having the above configuration, it is possible to maintain a state in which static frictional force does not act, improve resolution, and improve hysteresis characteristics. The frequency of the square wave signal is predetermined according to the characteristics of the electromagnetic proportional valve and drive system, and the movement position of the valve body can be controlled by changing the 0N-OFF ratio. From the viewpoint of improving resolution and improving hysteresis characteristics, the vibration III range of the valve body should be applied to the solenoid (34) as much as possible within a range that does not affect the actual flow rate proportional control and pressure proportional control 2D. It is preferable to cover it so that the applied current varies.

Fluctuations in the current applied to the solenoid (34) will be explained in detail.

If only a diode is used as a surge absorption circuit, a large current will flow through the circuit consisting of the diode and solenoid in series the moment the square wave signal turns OFF, and the amplitude of the maximum and minimum current values will become small. ,diode(
A resistor (36) is connected in series with the resistor (37).

However, when such a surge absorption circuit is adopted, the current that gradually increases due to the action of the inductance of the solenoid itself while the rectangular wave signal is ON decreases while the rectangular wave signal is OFF. (36), but if the voltage applied to the solenoid is low, the response at startup will be poor, and the amount of current change will be too small when the average voltage is low, causing sufficient vibration of the valve body. There is a problem that no effect can be obtained.

To solve this problem, solenoid (34)
It is conceivable to increase the voltage applied to the problems will occur.

<Object of the invention> This invention was made in view of the above problems,
The purpose of the present invention is to provide an electromagnetic proportional valve side m device that can increase the amount of vibration when the gIvJffi of the valve body is small, and can prevent the vibration from exceeding the permissible limit when the amount of movement is large. .

Means for Solving the Problems> In order to achieve the above object, the electromagnetic proportional valve control device of the present invention includes an opening indicating means for generating a signal indicating the opening of the electromagnetic proportional valve, and a predetermined opening. an optical oscillation means that oscillates at a frequency;
A rectangular waveform receiving an opening instruction signal from the opening instruction means and an oscillation signal from the oscillation means, generates a rectangular wave signal having an average voltage corresponding to the opening instruction signal, and supplies the signal to the solenoid of the electromagnetic proportional valve. wave signal generation means; reference frequency setting means for setting the oscillation frequency of the oscillation means as a predetermined reference value; The present invention is characterized by comprising frequency increasing means for increasing the oscillation frequency of the oscillating means.

In the electromagnetic proportional valve control device having the above configuration, when a signal indicating a relatively small opening is supplied from the opening indicating means to the square wave signal generating means, the reference frequency setting means A reference oscillation frequency signal from an oscillation means operating based on the above is supplied to the rectangular wave signal generating means, which generates a rectangular wave signal having the reference oscillation frequency and an average voltage corresponding to the opening instruction signal. By supplying the solenoid to the solenoid of the electromagnetic proportional valve, the valve body is moved to the position corresponding to the specified opening degree with vibration within a range that does not affect proportional flow rate control and proportional pressure control. Can be done.

Further, when a signal instructing a large opening degree from the opening degree indication means is supplied to the square wave signal generation means, the frequency increasing means operates to make the oscillation frequency of the oscillation means correspond to the degree indication signal. The square wave signal generating means generates a square wave signal having the increased frequency and an average voltage corresponding to the opening instruction signal and supplies it to the solenoid of the electromagnetic proportional valve. The valve body can be moved to a position corresponding to the instructed opening while suppressing vibration within a range that does not affect the flow rate proportional control and the pressure proportional control.

<Example> FIG. 5 is a schematic vertical sectional view showing an example of an electromagnetic proportional valve.
Consists of an electromagnetic proportional valve (6) equipped with a variable throttle (22c) and a pressure compensation valve (50) that maintains a constant differential pressure before and after the variable throttle (22c). A valve spool (23) having a large diameter portion and a small diameter portion is slidably built into the valve casing (21) in which a flow path (22) is formed, and the valve spool C23) is biased in a predetermined direction. A spring (24) that moves the valve spool (23) against the urging force of the spring (24) and a slide (5) that moves the valve spool (23) are attached.

Therefore, a force corresponding to the voltage applied to the Trayed (5) acts on the valve spool (23), and the valve spool (23) is moved to a position where it balances the biasing force of the spring (24), and the inlet flow path ( A predetermined constriction part (22c) is formed between the constriction part 22a) and the outlet flow path (22b), and the differential pressure before and after the constriction part (22c) is kept constant by the normally closed expansion pressure compensation valve (50). Flow rate proportional control can be performed.

FIG. 1 is a block diagram showing an embodiment of the electromagnetic proportional valve control i11] device of the present invention.

An opening instruction section (1) that receives a command signal from an external control device (not shown) and outputs an opening instruction section
), an electromagnetic proportional valve (6), a frequency increase start point setting section (12) that outputs a frequency increase start point setting signal (see Fig. 2B) based on the characteristics of the drive system, and a power supply section (9). ), an electromagnetic proportional valve (6), and a reference frequency setting section (11) that outputs a reference frequency setting signal of a rectangular wave signal to be applied, taking into consideration the characteristics of the drive system.

An opening instruction signal output from the opening instruction section (1);
A feedback signal from the solenoid (5) that drives the electromagnetic proportional valve (6) is input to the constant current calculation section (2),
A calculation output signal calculated so that the difference between the two human force signals becomes zero is output. Further, an oscillation section (10) that receives the reference frequency setting signal outputted from the reference frequency setting section (11) and oscillates at the reference frequency sends the reference frequency oscillation signal to one input terminal of the comparison section (3). By supplying the calculated output signal to the other input terminal of the comparator (3), a rectangular wave signal with a predetermined duty ratio is output. The rectangular wave signal is supplied to the gate terminal of the power switching unit (4) to which the power supply voltage from the power supply unit (9) is supplied, so that the power supply voltage signal having the duty ratio is ), and the electromagnetic proportional valve (6) can be driven to a specified opening degree with vibration in a minute range.

The opening degree instruction @ is input to the comparison section (13) together with the frequency increase start point setting signal, and when the opening degree instruction signal becomes large, the frequency increase instruction signal is sent to the frequency increase 'llAg section (14). ). In addition to the frequency increase instruction signal, the frequency increase calculation section (14) is supplied with the opening instruction signal and the increase rate setting signal q from the frequency increase rate setting section (15). The calculated signal is supplied to the reference frequency setting section (11).

In addition, the feedback from the solenoid (5) to the constant current calculation unit (2) is the output signal from the current detection unit (7) that detects the current of the solenoid (5) and converts it into voltage, and the current detection unit (71). The smoothing part (
8), but the smooth part (
The function of 8) is added to the constant current calculation section (2) to create a smoothing section (8).
It is also possible to omit.

Furthermore, the output waveform from the oscillation section 0 is not particularly limited, but is preferably a triangular wave or a sawtooth wave.

The operation of the electromagnetic proportional valve control device having the above configuration is as follows.

(1) When a small opening is commanded (see Figures 2 and 4, middle area ■), in this case, the opening instruction signal is smaller than the frequency increase start point setting signal, so the frequency increase is calculated. Section (14) does not operate.

Therefore, the oscillation section (g) outputs an oscillation signal of the reference frequency based on the reference frequency setting signal from the reference frequency setting section (11).

Then, the output signal from the constant current calculation unit ('2J) which receives the opening instruction signal and the feedback signal, and the above oscillation signal are input to the comparison unit (3), and the duty ratio corresponding to the magnitude relationship between the two signals is input. Since the rectangular wave signal is input to the gate terminal of the power switching section (4), the power supply voltage is changed to the solenoid (5) with a duty equal to the above short wave signal.
is applied to As a result, the solenoid (5) applies a driving force corresponding to the average applied voltage to the valve spool (23),
At the position where the biasing force of the spring (24) is averaged, it comes to a halt state while making slight vibrations, and proportional control of the flow rate corresponding to the opening command can be performed.

(n) When a large opening is commanded (Figures 2 and 4)
In this case, since the opening instruction signal is larger than the frequency increase start point setting signal, the comparison unit (13)
outputs a frequency increase instruction signal, and the frequency increase calculation section (
14) calculates a frequency increase calculation signal determined based on the opening degree instruction 4rJ@ and the increase rate setting signal, and supplies it to the reference frequency setting section (11). Therefore, the reference frequency setting section (11) outputs a frequency setting signal increased in accordance with the opening instruction signal, and the oscillation section (g))
An oscillation signal with a constant frequency is output by the frequency setting signal.

As a result, a rectangular wave voltage having the above-mentioned frequency and a duty corresponding to the opening degree instruction signal is supplied to the Trayed (5). In this case, since a large opening is instructed, the vibration of the valve spool (23) will increase if left as is, but since the frequency has been increased, the vibration does not increase and falls within the allowable range. while holding the valve spool (23) to the position corresponding to the opening instruction signal.
) can be moved to perform flow rate proportionality 11i1Jl.

FIG. 3 is a block diagram showing another embodiment, and the difference from the above embodiment is that the frequency increase start point setting section (12)
The comparison section (13) is replaced with each frequency increase start point setting section (121) (122)...(12n).
, and each comparison section (131
) (132)...Switching units (171) (172) and (172) operated by output signals from (13n)
...(17n) and each switching section (171) (17
2) ... (17n) through the reference frequency setting section (11
), the structure of the other parts is the same except for the frequency additivity setting units (161), (162), . . . (16n) that output the frequency increment signal supplied to The same parts are given the same reference numerals.

Therefore, in the case of this embodiment, the oscillation frequency of the oscillator (G) is increased in stages in response to an increase in the opening instruction signal, and even when Of1 degree becomes large, the oscillation frequency of the oscillation part (G) ) can be operated in proportion to the flow rate while suppressing the vibration within the permissible range.

It should be noted that the present invention is not limited to the above-mentioned embodiments; for example, it is possible to perform pressure proportional control (
However, in this case, the vibrations allowed to the valve body are smaller than in the case of flow rate proportional control), and various other design changes can be made within the scope of the invention without changing the gist of the invention.

<Effects of the Invention> As described above, the present invention has the advantage that when a rectangular wave voltage is applied to the solenoid of the ff1l proportional valve to move the valve body to a desired position with minute vibrations, the average applied voltage is The square wave voltage frequency is held at a small predetermined value while the voltage is small, and when the average applied voltage is large, the square wave voltage frequency is increased, so static friction is reduced over the entire range where flow proportional control and pressure proportional control are performed. It has the unique effect of being able to eliminate the problem and also to perform accurate proportional control in response to external commands.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing one embodiment of the electromagnetic proportional valve control TA device of the present invention, Fig. 2 is a block diagram showing signal waveforms of each part, Fig. 3 is a block diagram showing another embodiment, Fig. 14 FIG. 5 is a longitudinal sectional view showing an example of an electromagnetic proportional valve, and FIG. 6 is a block diagram showing a conventional example. (1)...Opening degree indicating section, (3)...Comparing section, (4)
...power switching section, (5) ... solenoid, (6) ... electromagnetic proportional valve, ■ ... oscillation section, (11)
... Reference frequency setting section, (120121) (122) ... (12n) ... Frequency addition start point setting section, (13) (131) (132) ... (13n) ...
Comparison section, (14)... Frequency increase calculation section, (15)... Frequency increase rate setting section, (16) (161)! 1B2)...(16n)...
・Frequency increment setting section, (171) (172)...(
17n) Switching unit patent applicant Daikin Industries, Ltd. Valve body movement amount - Figure 4

Claims (1)

[Claims] 1. Generates a signal that instructs the opening of the solenoid proportional valve. with an opening indicating means and a predetermined frequency. Oscillating means for oscillating and the opening indicating means from the opening instruction signal and the oscillation means. Using the oscillation signal as input, the above opening instruction is given. a square wave with an average voltage corresponding to the signal The solenoid of the electromagnetic proportional valve generates a signal a square wave signal generation means for supplying the The oscillation frequency of the oscillation means is set to a predetermined reference value. and a reference frequency setting means to be set by The opening degree indication signal is larger than the predetermined reference value. If the A frequency that increases the oscillation frequency of the recording oscillation means. characterized by comprising a wave number increasing means. Electromagnetic proportional valve control device. 2. The frequency increasing means responds to the opening signal. Continuously increase the oscillation frequency accordingly Claim 1 above, which is Solenoid proportional valve control device. 3. The frequency increasing means responds to the opening signal. Increase the oscillation frequency step by step accordingly. Claim 1 above, which is Solenoid proportional valve control device.