JPH03293567A - Apparatus for diagnosing operation of movable part operated by electromagnetic force - Google Patents

Abstract

PURPOSE:To easily judge quality and the kind of trouble by providing a means detecting the current of an electromagnetic coil, a means digitalizing the detection signal thereof positively and negatively and a means judging the quality of a movable part from both count numbers of the duration time of a positive signal and the number of times of a negative signal. CONSTITUTION:The current of an electromagnetic coil 2 is detected by a current transformer 1 and the signal thereof is differentiated by a differentiation circuit 4 to be divided into positive and negative signals and trouble cause division at the times when a solenoid valve 20 is superior and inferior is cleared. Further, the positive and negative differentiation signals are digitally converted by A/D converters 5a, 5b and the trouble cause at the times when the solenoid valve 20 is superior and inferior is judged on the basis of the count value of a frequency counter 6 and that of a time counter 7 by a judging circuit 9.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is intended to investigate the quality of the operating state of the movable parts of devices such as solenoid valves, electromagnetic brakes, electromagnetic clutches, etc., which have movable parts that operate by the electromagnetic force of electromagnetic coils. The present invention relates to a device for determining.

(Prior Art) For example, electromagnetic valves are often used in fluid flow paths for liquids, gases, etc., and the electromagnetic valves are opened w5 by remote control. This electromagnetic valve excites a core with an electromagnetic coil to draw a spool into the electromagnetic coil against a spring force, thereby opening and closing the electromagnetic valve.

However, with this solenoid valve, if scum or dust gets mixed in with the liquid, gas, or other fluid in the fluid flow path and adheres to the spool, the spool gets caught and cannot operate smoothly.
If the spool stops working, or if the electromagnetic coil is not energized due to the electric circuit (including the electromagnetic coil) that operates the spool, or if it is energized twice in a row (hereinafter referred to as re-excitation), etc. arise.

As a device for detecting a failure of this solenoid valve, for example, as described in Japanese Utility Model Publication No. 55-5822, the solenoid valve can be used by detecting the time at which dip and αG occur by taking advantage of the characteristics of (1) and (3) below. There is a device that determines the quality of the product.

(2) When the spool operates normally, a dip point G occurs in the current flowing through the electromagnetic coil at the beginning of the spool's operation, as indicated by C1 in FIG.

(2) The time at which this decisive point G occurs varies depending on the spool operating state.

(Problem to be solved by the invention) However, solenoid valves have manufacturing dimensional errors, and there are differences in conditions such as changes in the viscosity of the fluid due to differences in the type of fluid to be controlled by the solenoid valve, fluid temperature, etc. Therefore, the occurrence time of dip point G that occurs during spool operation differs depending on each solenoid valve, and in the device described in the above-mentioned Japanese Utility Model Publication No. 55-5822, the occurrence time of dip point G during normal spool operation is different for each solenoid valve. It is very complicated to judge whether the solenoid valve is good or not by comparing it with the generation time of the decisive point G detected for each solenoid valve. To provide a device that can easily determine whether a valve is good or bad and the type of failure.

(Means for Solving the Problems) The present invention provides an operation diagnosis device for a movable part operated by the electromagnetic force of an electromagnetic coil, which includes a differentiating means for detecting a current flowing through the electromagnetic coil and differentiating the detected signal; A/D conversion means that converts a positive differential signal from the means into a positive digital signal and a negative differential signal from the means into a negative digital signal, and counts the duration of the positive digital signal from the A/D conversion means. a time counting means for counting the number of negative digital signals from the A/D converting means; and a frequency counting means for counting the number of negative digital signals from the A/D converting means; This is an operation diagnostic device for a movable part that operates by electromagnetic force and has a determination means for determining whether the operation is good or bad, and a display means for displaying the determination result from the determination means.

(Function) As a result of various experiments and studies to solve the above problems, the present inventors completed the present invention with the knowledge that it is extremely easy to determine pass/fail by differentiating the current flowing through the electromagnetic coil. did.

The operation of the present invention will be explained in the case of a solenoid valve with reference to FIG.

In the present invention, first, a current flowing through the electromagnetic coil 2 is detected by a current transformer 1 provided in the electromagnetic coil 2, and the current flowing through the electromagnetic coil 2 is detected. r!
By differentiating the JI signal using a differentiating circuit 4 as a differentiating means and classifying it into positive and negative signals, it becomes clear whether the solenoid valve is good or bad, and if it is bad, it can be clearly classified by cause of failure. Furthermore, this differential signal is converted into negative and positive A/D converters 5 & 5 as A/D conversion means.
, 5b converts it into a digital signal, and based on the frequency of this digital signal, the frequency as a time counting means, and the count value of the time counter 6.7, a judgment circuit 9 as a judgment means determines whether the solenoid valve is good or bad. This makes it possible to determine the cause of a failure. Therefore, the structure is simple and the determination is not complicated.

Note that a special current transformer 1 is not required, and commercially available clamp type, Hall element type, etc. can be used.

(Example) An embodiment of the present invention will be described with reference to FIGS. 1 to 5.

The device shown in FIG. 1 includes a current transformer 1 that detects the current flowing through the electromagnetic coil 2 by clamping it on the covering of the electromagnetic coil 2 of the electromagnetic valve 20, and a high-frequency component of the detection signal from the current transformer 1. Coilter 3 that removes and passes only low frequency components,
a differentiating circuit 4 that differentiates the current output from the coiler 3;
A negative A/D converter 5m that converts the negative signal of the differential signal output from the differentiator circuit 4 into a digital signal, and a positive A/D converter that converts the positive signal of the differential signal output from the differentiator circuit 4 into a digital signal. 5b, a frequency counter 6 for counting the digital signal loss from the negative A/D converter 5a, a positive A/D converter 5a;
A time counter 7 that counts the duration of the digital signal from the D converter 5b, and a NOR circuit 8 that outputs when no signal is output from either the positive A/D'li converter 5b or the negative A/D converter 5a. , a determination circuit 9 that determines the quality of the electromagnetic valve based on signals from a frequency counter 6, a time counter 7, and a c/NOR circuit 8, and displays the quality on a display 10.

The solenoid valve 20 is moved by a core 21 that is magnetized by being excited by an electromagnetic coil 2 , a push pin 22 that is attracted by the electromagnetic core 21 , and a push pin 22 that is attracted to the core 21 to open an oil pipe 24 . It consists of a spool 23 that opens and closes, and a coiled spring 25 provided on the bushing pin 22.

Next, the bushing pin 22 of the solenoid valve 20 and the spool 2
The quality of the moving operation in step 3 will be specifically explained.

When a current is applied to the electromagnetic coil 2 of the electromagnetic valve 20 to excite the core 21 to attract the bushing pin 22 to the core 21 and operate the spool 23, a current containing a transient current flows through the electromagnetic coil 2. Therefore, this current is detected by the current transformer 1 provided in the electromagnetic coil 2 and output to the coil transformer 3. Since the detection signal detected by the current transformer 1 may include a harmonic wave component due to some reason, this high-harmonic wave component is transferred by a coiler 3 and sent to a differentiating circuit 4.

The coiler 3 outputs any one of currents A and -E1 as shown in FIG.

1! In Fig. p & 2, the two-dot chain line A1 shows the case where the spool 23 is caught and does not operate, and the solid line B1 shows the case where the spool 23 operates normally in the first excitation as shown below, and then the current instantaneously increases. This is the case when the current flows through the electromagnetic coil again and re-excites the core 21. 1st chain @C is the case when the spool 23 is operating normally, and the dotted line is when the spool 23 is caught. This is the case when it is working. Moreover, a solid line E is a case where no current flows through the electromagnetic coil 2.

When the currents A1 to E, including such transient currents, are differentiated by the differentiating circuit 4, differential signals A2 to E as shown in FIG. 3 are obtained.
2, which is input to the negative A/D converter 5a and the positive A/D converter 5b. In Figure 3, the two-dot chain line A2 represents the two-point nod MA in Figure 2, which is true! B2 is the solid line B1, 1.
α chain #! I C2 is the dashed line C1, and the dotted line D2 is the point AI
D, and the solid line E2 is the differential signal obtained by differentiating the real line 41E.

The positive A/D converter 5b receives the differential signal A differentiated by the differentiating circuit 4.
It outputs a digital signal during the period when E2 to E2 are positive, and the output signal is shown in FIG.
In the figure, the two-dot chain line A is the two-dot chain line A2 in FIG. It is a digital signal.

Further, the negative A/D converter 5a outputs a digital signal during a period in which the differential signals C2 and D2 differentiated by the differentiating circuit 4 are negative, and the output signal is converted into a digital signal as shown in FIG. In Figure 5, 1. The α chain line c4 is the one-dot chain II in Fig. 3.
C2, dotted line D4 is breath! D, are each digital signals.

The signal C shown in FIG. 5 output from the negative A/D converter 5a,
,D, are input to the frequency counter 6, where the signals C1,
The number of times D is turned on is counted and input to the determination circuit 9. In addition, the time counter 7 is connected to a positive A/D converter 5b.
The time during which the signals A-D shown in FIG.

This determination circuit 9: (1) determines whether the operation of the spool 23 is normal or abnormal based on the count number N input from the frequency counter 6; that is, if the count value N at the frequency counter 6 is 1''c, the time counter When there are 7 signals input, it is the case of the differential signal shown in 1.V line C2 in Fig. 3, and it is determined that there is only one deep fish G, and that the operation is normal, and the signal is 0.
When a signal is input from the time counter 7 and the count value from the frequency counter 6 is N>1, it is a differential signal shown by the dotted line D2 in Fig. 3, which indicates that multiple dip fish G have occurred. abnormality (spool 23 is caught)
It seems to be working! (II) Also, based on the count number T input from the time counter 7, it is determined whether the spool 23 is stuck and does not operate due to re-excitation. When the force Hund number T (ON period in Figure 5) from the force counter 7 is smaller than the predetermined number (predetermined time: 20±S m5) A and there is no signal from the frequency counter 6, the In the case of the differential signal shown by the two-dot chain line A2, it is determined that a stick has occurred;
When there is no signal input from frequency counter 6,
In the case of the differential signal shown by the solid line B2 in the figure, it is determined that re-excitation has occurred, and (III) further, the determination circuit 9 determines that the signal of the negative A/D converter 5a and the positive A/D converter 5b is N
It is input through the OR circuit 8, and if there is a signal input from the NOR circuit 8, it is determined that the electromagnetic coil 2 is not excited.In other words, if there is a signal input from the NOR circuit 8, it is determined that the electromagnetic coil 2 is not excited. No signal is output from either the converter 5a or the positive A/D converter 5b, which means that no current flows through the electromagnetic coil 2.

In this way, the determination result determined by the determination circuit 9 is displayed on the display 10.

In addition, in this embodiment, the negative A/D converter 5a and the positive A/D
p of the electromagnetic coil 2 by the signal output from the converter 5b.
Although the Am magnetism was determined, it is not limited to this, and the coil tar 3
Alternatively, the determination may be made based on the signal output from the differentiating circuit 4.

Further, each of the circuits described above does not require any special equipment, and may be constructed using commercially available ICs or may use a microcomputer.

Furthermore, although this embodiment has been described with respect to a solenoid valve, the present invention is not limited to this, and any device having a movable part operated by the electromagnetic force of an electromagnet may be used, such as an electromagnetic brake, an electromagnetic brake, an electromagnetic circuit breaker, etc. It can also be applied to devices such as

(Effects of the Invention) As explained above, the present invention has a simple structure, and even if the manufacturing accuracy of the solenoid valve is slightly different, or the operating conditions of the solenoid valve are different, the present invention can accurately determine whether the solenoid valve is good or not. , and in the case of failure, the cause of the failure can also be determined, and the maintenance and regular inspection of the electromagnetic valve are facilitated.This has a great effect in this field.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an embodiment of the present invention, Fig. 2 is a diagram showing the output current from the coiler, Fig. 3 is a diagram showing the differential signal from the differentiation circuit, and Fig. 4 is a diagram showing positive A/D conversion. FIG. 5 is a diagram showing a digital signal from a negative A/D converter. DESCRIPTION OF SYMBOLS 1... Current transformer, 2... Electromagnetic coil, 3... Coilter 4... Differential circuit, 5a... Negative A/D converter, 5b...-Positive A/D converter, 6 ...Frequency counter 7...Time counter, 8...NOR circuit, 9
... Judgment circuit, 10... Display, 20... Solenoid valve, 21... Core, 22... Bushbin, 23...
・Spool, 24...Oil pipe, 25...Spring.

Claims (1)

[Claims] (1) An operation diagnostic device for a movable part that operates by the electromagnetic force of an electromagnetic coil, which includes a differentiating means for detecting the current flowing through the electromagnetic coil and differentiating the detected signal, and a positive differential signal from the differentiating means for detecting the current flowing through the electromagnetic coil and differentiating the detected signal. A/D conversion means for converting each negative differential signal into a negative digital signal; time counting means for counting the duration of the positive digital signal from the A/D conversion means; a frequency counting means for counting the number of negative digital signals from the frequency counting means; a determining means for determining whether the operation of the movable part is good or bad based on the count from the frequency counting means and the count from the time counting means; and the determining means. An apparatus for diagnosing the operation of a movable part operated by electromagnetic force, characterized in that it has a display means for displaying a determination result from the means.