JPH09262510A - Monitoring device for degree in dirt of electrostatic coating machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically and quantitatively obtain indexes for maintenance inspection and decision of its interval by calculating the mean value of detected load current value in a set monitor range of a high voltage generator and comparing the calculated mean value with set value. SOLUTION: A leakage current detection means 40 is formed of an earth band 41 wound on the opposite side of a bell (load part) 13, a leader line 42 and a leakage current detector 43 to detect leakage current Ir which flows through the body 11 from the bell 13 forming the paint spray means of an electrostatic coating machine 10 and is changed by a degree in dirt. Detected leakage current value Ii is amplified by an amplifier 44 and inputted to a CPU 51 and sampling is performed only in the prescribed number of times and thereafter mean value Ai is calculated automatically and quantitatively. Then, the calculated mean value Ai is compared with set value As. In the case of Ai>=As, a buzzer 26 is rumbled by outputting a monitor alarm signal of the effect becoming the degree in dirt appropriate to the set value As.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a static charge for electrostatically coating a work while charging a atomized paint by applying a high voltage from a high voltage generator to a charging part mounted on a main body forming a paint spraying means. The present invention relates to a contamination degree monitoring device for an electric coating machine.

[0002]

2. Description of the Related Art In FIG. 4, an electrostatic coating machine 10 includes a main body 11 made of an electrically insulating material, and a paint spraying means including a bell (charging portion) 13 mounted at an air turbine 12 built therein so as to be rotatable at a high speed. It is provided with a high voltage generator 30P, paint supply means (not shown) and the like. 100 is a robot arm.

The high voltage generator 30P comprises an original power source generation circuit 32, a voltage controller 32R and a high voltage generator 31P, and a high frequency (for example, several kHz to several tens of kHz) from the voltage controller 32R through a cable 29. The low voltage Vl (for example, 12 to 24V) is supplied to the high voltage generator 31P built in the main body 11.

In the case of FIG. 4, the high voltage generator 31P comprises a step-up transformer and a Cockcroft circuit. High voltage (for example, -60 kV) Vh generated by this
Is applied to the bell 13 via the flange portion 14 of the air turbine 12 and the air turbine 12 itself. Therefore, the bell 13 can charge the paint while atomizing the paint, so that the grounded work W can be electrostatically painted.

Electrostatic coating machine 1 for applying such high voltage Vh
At 0, a short circuit may occur between the bell 13 and other grounded members. Therefore, overload protection means 33 is provided to ensure safety.

The overload protection means 33 has a detection current value Id obtained by detecting the load current I used for charging the atomized paint with the load current detector 35, and is preset in the setter 34. The setting value Is is compared, and when Id ≧ Is, the cutoff signal S is output so that the source power generation circuit 32 can be cut off.

The set value Is is carefully selected in light of the operation mode and based on experience, but is generally twice the normal load current I value (for example, 100 μA) (200 μA).
It is selected and set to the degree.

[0008]

When atomized paint, dust, etc. once adhere to the bell 13 and the outer peripheral surface of the main body 11, the adhered paint and the like become solid particles with the passage of time and the bell 13 The wind and the turbulence caused by the high-speed rotation scatter and adhere to the work W. That is, the coating quality deteriorates. Therefore, for example, during regular maintenance and inspection, the painting operation is stopped and the cleaning is performed.

However, it is difficult to uniquely and quantitatively determine the degree of contamination due to the adherence of paint or the like on the paint spraying means (11, 13 etc.). This is because the environment of use varies slightly depending on many factors such as the rotation speed of the bell 13, the form and size of the main body 11, and the degree of overlap of each factor. Further, depending on the degree of contamination due to the adherence of paint or the like to the paint spraying means (11, 13 etc.), not only the power loss is increased before the deterioration of the coating quality is caused but also the apparent malfunction of the overload protection means 33 is caused. May be caused. Therefore, there is a strong demand for a specific index and a monitoring method for determining the interval of maintenance and inspection for dirt while taking into consideration prevention of power loss and avoidance of malfunction.

An object of the present invention is to provide an apparatus for monitoring the degree of contamination of an electrostatic coating machine which can automatically and quantitatively monitor a useful index for determining the necessity of maintenance and inspection and the interval thereof.

[0011]

Means for Solving the Problems Paint spraying means (11, 1)
When the degree of contamination of 3) is analyzed, many of the attached dust, paint, etc. have conductivity. In particular, the addition of moisture increases the conductivity. Even non-conductive paint becomes conductive when it absorbs water. Therefore, when the conductivity is increased, the leak current easily flows from the bell 13 to which the high voltage Vh is applied to the outside (ground) through the main body 11. Further, even if the conductivity is kept at a constant level, the demand for further reduction in size and weight of the paint spraying means (11) becomes stronger in connection with the robot, for example, in the bell 13 today.
And a carrier for the main body 11 (for example, the robot arm 100)
Since the distance between and is shortened, the chances of generating a leak current tend to increase.

However, the leak current is generated when factors such as the degree of contamination, the presence or absence of water adhesion, and the value of the high voltage Vh overlap, and the load current itself also fluctuates. Difficult to figure out. Moreover, the leak current itself does not always occur continuously, and the leak current occurring on one side may suddenly increase in value. For example, when the humidity temporarily increases due to the inflow of the atmosphere. Further, the load current of the high-voltage generator often transiently increases immediately after the start of application of the high voltage Vh, for example, as shown in FIG. 3B, regardless of whether or not a leak current is generated.

The present invention pays attention to such peculiar technical matters and recognizes the fact that the leakage current flows in as a kind of load current of the high voltage generator, and recognizes a transient phenomenon at the start of high voltage application. Detect the actual load current after introducing the concept of setting monitoring range to eliminate the influence and introducing the concept of average value to eliminate the influence of the load current equivalent to an exceptionally or temporary large leak current. In addition, the average value of the load current values detected in the set monitoring range is calculated, and the degree of contamination of the paint spraying means can be monitored by comparing the average value with the preset setting value.

That is, according to the present invention, electrostatic coating is performed by electrostatically painting a work while applying a high voltage from a high voltage generator to a charging portion mounted on a main body forming a paint spraying means while charging the atomized paint. An apparatus for monitoring the degree of contamination of a machine, the load current detecting means for directly or indirectly detecting the value of the load current of the high-voltage generator, and the load current within the set monitoring range detected by the load current detecting means. An average value calculating means for calculating an average value of the values, a determining means for comparing the preset setting value with the calculated average value and determining whether the average value is equal to or more than the setting value, and this determining means. And a monitoring alarm output control means for outputting a monitoring alarm when the average value is determined to be equal to or larger than the set value, and the average value of the detected load current values is used to measure the contamination degree of the paint spraying means. Is formed so that it can be monitored To.

In this invention, when the load current detecting means directly or indirectly detects the value of the load current of the high voltage generator, the average value calculating means calculates the average value of the detected load current values within the set monitoring range. . The determining means compares the average value with a preset setting value and determines that the average value is equal to or higher than the setting value. Then, the monitoring alarm output control means outputs the monitoring alarm by, for example, displaying, sounding, printing, or the like.

Therefore, if the set value is selected and determined based on the average value of the load current value detected immediately after the maintenance inspection and is preset, the contamination degree of the paint spraying means is warned even before the next maintenance inspection. It is possible to easily monitor and monitor the form and to easily and accurately determine the necessity and interval of maintenance and inspection from the index.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, this contamination degree monitoring device is introduced into an electrostatic coating machine 10 having a basic configuration similar to that of the conventional example (FIG. 4), and a load current detecting means (40) and an average Value calculation means (51, 52), discrimination means (51, 52), and monitoring alarm output control means (51, 5)
2) is provided, and the detected setting monitoring range (t2 to t3)
The average value Ai of the load current values (Ii) in the above is calculated, and this average value Ai is compared with the set value As, and the paint spraying means (1
1, 13) is formed so that the degree of contamination can be monitored.

In FIG. 1 showing the overall structure, an electrostatic coating machine 10 includes a paint spraying means (11, 13 etc.), a drive control panel 2
0, a high voltage generator 30, paint supply means (not shown), etc., and at least 1 by the robot arm 100.
The work W can be painted while reciprocating in the dimension.

The drive control board 20 includes a drive control circuit (for example, a sequencer) 21 and can drive and control the paint supply means and the like by a proper amount at a proper time.

The high voltage generator 30 may have the same configuration (32, 32R, 31P) as in the conventional example (FIG. 4), but in this embodiment, an external system formed from the high voltage generator circuit 31 is used. There is. Further, it is connected to a current limiting resistor 39 provided in the main body 11 via a high voltage cable 37. The overload protection means 33, and the load current detector 35 and the setting device 34 necessary for this purpose are the same as those in the conventional example (FIG. 4).

Since the load current detecting means is a means for directly or indirectly detecting the load current I (I + Ir) of the high voltage generator 30 (31), its detecting method can be appropriately selected. However, in this embodiment, the leak current detecting means 40 capable of detecting the leak current Ir directly connected to the degree of contamination is formed by the indirect detection method.

That is, the leak current Ir flowing from the bell (charging portion) 13 forming the paint spraying means through the main body 11 changes depending on the degree of contamination due to adhesion of dust, paint, etc., but charges (charges) the atomized paint. When compared with the original value of the load current I used for (for example, 130 μA), it is as small as 10 to 60 μA. Therefore, rather than detecting the leak current Ir representing the degree of contamination as the sum of the load current I, the detection of the leak current Ir itself can improve the resolution and facilitate the detection itself.

Thus, the leak current detecting means 40 is the earth band 4 wound on the side of the main body 11 opposite to the bell 13.
1, a lead wire 42, and a leak current detector 43. Further, an amplifier 44 is provided to detect the detected leak current value I
i is amplified. In addition, 45 is an A / D converter.

By the way, the leakage current Ir is, for example, as shown in FIG.
As shown in (A), it tends to change moment by moment. Further, the load current I + Ir to be detected, which is the sum of the original load current I and the leak current Ir, is the high voltage Vh as shown in FIG.
The voltage rises transiently at the start of application (time t1) and stabilizes from the start of paint spraying (time t2). Further, it also rises transiently at the end of paint spraying at time t3. When the high voltage is cut off (time t4), it naturally becomes zero (0). Therefore, the set monitoring range in this embodiment is from the start of paint spraying (t2) to the end of paint spraying (t3).

Further, in this embodiment, the average value calculating means (51, 52), the discriminating means (51, 52) and the monitoring alarm output controlling means (51, 52) are utilized by using a personal computer (personal computer 50). It is built. You may make it build using the component (21) in the drive control panel 20.

The personal computer 50 has a CPU 51 and a ROM 5
2, RAM 53, keyboard (KB) 54, display (I
ND) 55, printer (PTR) 56, input port (I
/ P) 57 and an output port (O / P) 58.

A set value storage means 53M for storing the set value As is provided in a part of the storage area of the RAM 53. The set value As can be set and input by operating the keys of the keyboard 54, and the value can be changed. That is, the set value As is set, for example, as 120% of the average value Ai detected and calculated immediately after the maintenance and inspection, as shown in FIG.

The average value calculating means is composed of a ROM 52 storing an average value calculating program and a CPU 51,
When it is within the set monitoring range (t2 to t3) [YES in step (ST) 10 of FIG. 2], the leak current detecting means 40
The leak current value Ii detected in S1 is read through the amplifier 44, the A / D converter 45 and the input port 57 (S
T11), stored in the work area of RAM 53 (ST1
2) Do it. The data is read and stored a predetermined number of times (ST13). For example, 20 times per second. Then, the average value Ai is calculated (ST14). The calculated average value Ai is stored in the RAM 53.

This average value Ai can be displayed and output to the display 25 in the drive control board 20 together with the detected leak current value Ii for each sampling. This is so that the degree of deterioration before the set value As can be grasped. Further, the average value Ai in each set monitoring range can be displayed and output on the display 55 in the personal computer 50 together with the set value As, and can be printed out later by the printer 56. Therefore, it is possible to confirm an index useful for the necessity of maintenance and inspection not only on the spot but also after the fact.

The discriminating means is formed by the ROM 52 storing the discrimination control program and the CPU 51, and compares the calculated average value Ai with the preset setting value As to determine whether Ai ≧ As. Determine. That is, it is executed in ST16 of FIG.

The monitoring / warning output control means is a discrimination means (5
1, 52), it is determined that Ai ≧ As (ST16
If the answer is YES), a means for outputting a monitoring alarm output and a ROM 52 and a C storing a monitoring alarm output control program
It is formed from the PU 51 and is executed in ST17 of FIG. In this embodiment, the buzzer 2 provided in the drive control panel 20 shown in FIG. 1 is output by outputting the monitoring warning signal Sa.
6 is driven to output an alarm with a buzzer sound as an index. Further, the buzzer sound continues until it is reset by key operation. Further, it is formed to output a monitor display alarm to the display 25. Of course, it is also possible to form a monitor alarm display output on the display 55 in the personal computer 50 or a monitor alarm print output by the printer 56.

Next, the operation and operation of this embodiment will be described. The drive control circuit 21 controls the paint supply means,
Bell 13 to which high voltage Vh (for example, −60 KV) is applied
Spray paint from. Therefore, the work W can be electrostatically coated. Original load current I in this case
Is, for example, 130 μA.

The leak current detecting means 40 forming the load current detecting means detects the leak current Ir which changes from moment to moment. Within the set monitoring range (t2 to t3) (S in FIG. 2)
(YES in T10) and the detected leak current value Ii are
It is amplified by the amplifier 44 and read by the CPU 51 via the A / D converter 45 and the input port 57 (S
T11) and is temporarily stored in the work area of the RAM 53 (ST12).

The CPU 51 has the RAM 5 in ST11 of FIG.
The detected leak current value Ii read from 3 is displayed on both displays 55,
No. 25 is displayed (ST15). Therefore, the operator of the drive control panel 20 in the booth can also quantitatively know the change in the degree of dirt (index) at that time.

When sampling (reading and storing) is performed a predetermined number of times (YES in ST13), the average value calculating means (51, 52) operates to automatically and quantitatively calculate the average value Ai (ST14). , RAM 53.
This average value Ai is also displayed as an index on both display devices 55 and 25 (ST15).

The discriminating means (51, 52) compares the calculated average value Ai with the set value As stored in the set value storage means 53M to discriminate whether or not Ai ≧ As (ST16). ) Do. Then, when it is determined that Ai ≧ As (YES in ST16), the monitoring / warning output control means (51, 52) outputs the monitoring / warning signal Sa indicating that the degree of contamination corresponds to the set value As ( In ST17), the buzzer 26 is driven. The buzzer sound continues until it is reset by key operation.

In FIG. 3A, even if the detected leak current value Ii1 has an exceptionally or temporarily large detected leak current value which is equal to or larger than the set value As, the average value within the set monitoring range is obtained. If the value Ai does not exceed the set value As, the monitoring alarm is not output (NO in ST16), so that the unnecessary monitoring alarm can be avoided. In the case of the detected leak current value Ii2, it can be said that there is no problem as long as it is the set value As shown by the dotted line.

According to this embodiment, however, the load current detecting means (40) and the average value calculating means (51, 52).
And a determination means (51, 52) and a monitoring alarm output control means (51, 52) are provided, and the detected setting monitoring range (t
2 to t3), the average value Ai of the load current values (Ii) is calculated, and the average value Ai is compared with the set value As to obtain the average value Ai.
Since it is formed so as to output a monitoring alarm when i becomes equal to or more than the set value As, it is possible to automatically and quantitatively monitor the contamination degree of the paint spraying means (11, 13) at any time during the coating operation. You can Therefore, cleaning of dirt and maintenance inspection can be performed timely and promptly, and the interval of maintenance inspection can be easily and accurately determined.

Further, the leak current detecting means 4 capable of detecting the leak current Ir, which is directly connected to the load current detecting means depending on the degree of contamination.
Since it is formed from 0, the detection is easy and the resolution can be improved.

Further, the leak current detecting means includes an earth band 41 wound around the paint spraying means (main body 11) and a leak current detector 43, and the bell (charging portion) 13 to the main body 1 are connected.
Since only the leak current Ir escaping to the outside (ground) through 1 can be detected, the contamination degree can be detected more quantitatively and accurately from this point as well.

In addition, the setting monitoring range is from when the paint spray starts (t2) to when the paint spray ends (t3) after the high voltage Vh is applied.
Since it is selected up to, the transient rapid increase region of the load current (I + Ir) including the leakage current Ir can be surely excluded. That is, the reliability of monitoring the degree of contamination can be further enhanced.

Further, the calculated average value Ai is displayed on the display unit 5.
Since it is formed to be displayed on 5, 25, 25, the operator of the personal computer 50 as well as the operator of the drive control panel 20 can easily confirm on the spot. Therefore, it is possible to urgently cope with the occurrence of sudden and unexpected stains.

Further, since the average value Ai is formed so that it can be printed out by the printer 56, it is effective as a reference material for later examination.

Since the set value As can be changed by operating the keys on the keyboard 54, the maintenance inspection interval can be made longer or shorter, and the degree of freedom can be selected, and the interval can be set according to the coating quality. Because it is adaptable. Further, it is possible to prevent the malfunction of the overload protection unit 33 from occurring.

The discriminating means is the CPU 51 and the ROM 52.
Since it is formed from, the discrimination processing can be performed at high speed.

Further, the monitoring and alarm output control means (51, 5)
In 2), since the buzzer 26 can be driven by outputting the monitoring alarm signal Sa, even a worker who cannot see the display can surely know the degree of contamination.

In the above embodiment, the load current detecting means is formed by the leak current detecting means 40, but it is formed by the load current detector 35 shown in FIG.
It may be formed so as to directly detect r). In this case, as shown in FIG. 3B, the set value As is naturally set lower than the set value Is (for example, 200 μA) for protecting the overload protection unit 33. For example, 150 μA obtained by adding the estimated average value of leak current Ir (for example, 20 μA) to the average value of detected load current value Id (for example, 130 μA) detected by using the load current detector 35 immediately after maintenance and inspection. To do.

Although the charging section is formed of the bell 13 rotating at a high speed, the present invention is not limited to this. For example, an air atomization method, an airless atomization method, or the like may be used.

[0049]

According to the present invention, the load current detecting means for directly or indirectly detecting the value of the load current of the high voltage generator, and the detected load within the setting monitoring range detected by the load current detecting means. An average value calculating means for calculating an average value of the current values, a determining means for comparing the preset setting value with the calculated average value and determining whether the average value is equal to or more than the setting value, Provided is a monitoring alarm output control means for outputting a monitoring alarm when the average value is determined to be equal to or higher than the set value by the determination means, and the average value of the detected load current values is used to measure the degree of contamination of the paint spraying means. Since it is formed so that it can be monitored, it has the following excellent effects.

An inverter for maintenance and inspection can be optimally and easily determined under a monitoring alarm that is an automatic and quantitative index. The need can be reliably monitored even before the scheduled maintenance. The operation mode can be selected according to the set value to be set. That is, the degree of freedom in selecting the length of the maintenance inspection interval is high, and the interval can be set according to the coating quality, so that the adaptability is wide. Further, it is possible to reduce power loss and prevent malfunction of the overload protection means. An alarm is output when the degree of contamination is equal to or greater than the set value, so that the progress can be reliably monitored at any time and anywhere. Therefore, it may be possible to clean before the coating quality deteriorates. Since dirt can be cleaned accurately, it is possible to meet the demand for a further reduction in size and weight of the paint spraying means.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation.

FIG. 3 is a diagram for explaining the relationship between a detected current value Ii and its average value Ai and set value As.

FIG. 4 is a diagram for explaining a conventional example and its problems.

[Explanation of symbols]

10 Electrostatic Coating Machine 11 Main Body (Paint Spraying Means) 13 Bell (Paint Spraying Means, Charging Section) 20 Drive Control Panel 30 High Voltage Generator 31 High Voltage Generating Circuit 33 Overload Protection Means 34 Setting Device 35 Load Current Detector ( Load current detecting means) 40 Leak current detecting means (load current detecting means) 41 Earth band 42 Lead wire 43 Leak current detector 45 A / D converter 50 Personal computer 51 CPU (average value calculating means, discriminating means, monitoring alarm output controlling means) ) 52 ROM (average value calculation means, determination means, monitoring alarm output control means) 53 RAM 53M set value storage means 54 keyboard 55 display 56 printer Vh high voltage I load current Ir leak current (load current) Ii detected leak current value Ai average value As set value

Claims (1)

[Claims] 1. The degree of contamination of an electrostatic coating machine that electrostatically coats a work while applying a high voltage from a high voltage generator to a charging part mounted on a main body forming a paint spraying means while charging the atomized paint. A monitoring device, wherein the load current detecting means for directly or indirectly detecting the value of the load current of the high-voltage generating device, and the average value of the load current values within the set monitoring range detected by the load current detecting means. An average value calculation means for calculating the average value, a determination means for comparing the preset setting value with the calculated average value to determine whether or not the average value is equal to or more than the set value, and the determination means And a monitoring alarm output control means for outputting a monitoring alarm output when it is determined that the value is equal to or more than a set value, and the contamination degree of the paint spraying means can be monitored by using the average value of the detected load current values. Of formed electrostatic coating machine Re degree monitoring device.