JPS646932Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to a coating robot that is capable of automatically detecting clogging of a nozzle tip of a coating gun that discharges coating material toward an object to be coated. Generally, a painting robot consists of a robot body that is operated by a signal from a robot control section, a paint gun that is installed at the end of an arm of the robot body and that discharges paint in response to a signal from the robot control section, and a paint gun that is operated by a signal from the robot control section. It generally consists of a paint pipe connecting between the paint gun and a paint source for supplying the paint. Here, for example, a microcomputer is used as the robot control section, and the movement of the robot body and the paint discharging interval, time, etc. of the coating gun are stored in advance in the memory section of the microcomputer by teaching operations, and are programmed. There is. Then, while the object to be coated, such as an automobile body, is being conveyed by the conveyor, the robot main body is operated in a playback manner according to the teaching content, and the supply of paint to the painting gun is controlled, so that the object to be coated is automatically touched. It is designed to be painted. By the way, if the paint gun is an airless type paint gun that uses hydraulic pressure to atomize the paint, the nozzle tip has an orifice diameter of 0.33 mm, for example.
It has a very small diameter of 0.38 mm, and if the paint is mixed with sludge, etc., it may cause clogging. In particular, when using a highly viscous anti-rust paint such as an undercoat, asbestos and the like contained therein often cause clogging. If the nozzle tip becomes clogged, the amount of paint ejected will be insufficient and normal painting will not be possible, so the nozzle tip must be replaced, and for this reason, it is necessary to constantly monitor the amount of paint ejected. be. Therefore, conventionally, as a means for monitoring the amount of paint discharged, for example, a flow meter is placed in the middle of the paint pipe.
Accordingly, a method has been adopted in which it is determined whether or not painting is being performed normally by measuring the cumulative flow rate or instantaneous flow rate of paint. However, in such a conventional method, the flow rate inside the paint pipe is, for example, several /
Not only is the flow rate very small (about a minute), but if paint is repeatedly supplied and stopped to the paint gun depending on the area to be painted, the flow becomes intermittent and it is extremely difficult to measure the flow rate. It was hot. In particular, various equipment such as the underside of the floor of an automobile body,
Due to the way parts are installed, there are many holes and spaces, and when performing so-called "blank painting" to avoid these holes, the flow rate fluctuates significantly because the paint supply and stop are performed at intervals of 1 to 10 seconds. However, there was a drawback that accurate flow measurement could not be performed. The present invention was developed in view of the above-mentioned drawbacks of the conventional technology, and in order to perform painting with a paint gun, the paint flow rate is measured based on the painting signal output from the robot control unit, and a preset For example, within a measurement time of 30 seconds or 60 seconds,
To provide a coating robot capable of outputting a clogging signal when the paint flow rate inputted from a flow meter becomes less than a preset lower limit discharge amount. In order to achieve the above object, the coating robot according to the present invention has a configuration that includes a flow meter installed in the middle of the paint pipe and a measurement timer to measure the flow rate of paint supplied to the paint gun. a lower limit discharge amount setting means for setting a lower limit discharge amount for each measurement time to be discharged from the coating gun; and a lower limit discharge amount setting means for the robot control means, a flowmeter, a measurement time setting means, and a lower limit discharge amount setting means. The robot control means measures the paint flow rate while the paint is being discharged from the paint gun according to a signal from the robot control means, and measures the paint flow rate input from the flow meter within the measuring time. It consists of a clogging detection means that outputs a clogging signal when the discharge amount is below the lower limit discharge amount. With the above-mentioned configuration, by simply setting the measurement time using the measurement time setting means and setting the lower limit discharge amount within the measurement time using the lower limit discharge amount setting means, the clogging detection means can count the paint flow rate from the flow meter. The presence or absence of clogging can be determined by comparing the size with the lower limit discharge amount. The present invention will be described below along with embodiments shown in the drawings. In FIG. 1, reference numeral 1 denotes a conveyor for conveying objects to be coated, which is provided in a coating booth, and the conveyor 1 is driven by a drive source 2, such as a motor. The object to be coated 3 placed on the conveyor 1 is conveyed within the coating booth by operating the drive source 2 . Reference numeral 4 denotes a robot body installed in a painting booth to perform painting work on the object 3 to be coated, and the robot body 4 includes a base 5 and a turntable 6 rotatably installed on the base 5. , a support 7 rotatably erected on the turntable 6, an arm 8 rotatably provided at the tip of the support 7, and a so-called elephant nose type provided at the tip of the arm 8. and a wrist 9, which are actuated by an actuator such as a hydraulic cylinder or a hydraulic motor. For this reason,
Each of the actuators is connected to a hydraulic power source 11 via a hydraulic pipe 10, and is operated by switching the hydraulic pressure in response to a signal from a robot control section, which will be described later.
Each joint mechanism such as the wrist 9 can be moved to any position. Reference numeral 12 denotes a painting gun provided at the tip of the wrist 9 of the robot body 4. The painting gun 12 is, for example, a hydraulic atomization type airless gun. Reference numeral 13 indicates a paint pipe, and one end of the paint pipe 13 is connected to the paint gun 1.
2, and the other end is connected to a paint tank 14. A pump 15 for feeding paint and a flow meter 16 are provided in the middle of the paint pipe 13, and an on-off valve 17 is provided near the paint gun 12. It is provided. Here, the paint tank 14 and pump 15 constitute a paint source. Further, as the flowmeter 16, for example, a positive displacement flowmeter or a turbine flowmeter is used, and a pulse transmitter 18 is mounted on the rotation axis of the flowmeter 16, and transmits a pulse signal proportional to the paint flow rate.
is installed. Furthermore, the on-off valve 17 opens and closes in response to a signal from a robot control section, which will be described later, and when the on-off valve 17 opens, the coating gun 12
The paint is discharged from the conveyor 1 so that each part of the object 3 to be coated that is transported by the conveyor 1 can be coated. Reference numeral 19 denotes a robot control section, and as described above, the memory section of the robot control section 19 contains robot operation signals for operating each actuator of the robot body 4, and opening/closing signals for controlling the paint discharge interval from the coating gun 12. Valve opening/closing signals for opening and closing the valve 17 (see FIG. 2, A) and the like are stored in advance through teaching operations and input as a program.
Then, the robot control section 19 outputs the robot operation signal to the robot body 4 via the signal line 20, outputs a valve opening/closing signal to the on-off valve 17 via the signal line 21, and further outputs the valve opening/closing signal to the on-off valve 17 via the signal line 22. A valve opening/closing signal A is output to the clogging detection section 23. The clogging detection section 23 is composed of, for example, a microcomputer, an arithmetic circuit, etc., and its input side includes a pulse transmitter 18, a robot control section 19, a measurement time setting device 24, and a lower limit discharge amount setting device 2.
5. It is connected to a delay time setting device 26, a coefficient corrector 27, etc., and its output side is connected to an alarm device 28 and a robot control section 19. Here, the measurement time setting device 24 sets the time to measure the flow rate, for example, 30 seconds or 60 seconds.
By setting it in seconds, the presence or absence of clogging is determined using this measurement time as a cycle. The lower limit discharge amount setter 25 sets the lower limit discharge amount for each unit time at which it is determined that clogging has occurred, such as 3/min or 0.1/sec, in accordance with the orifice diameter of the nozzle tip of the coating gun 12. It is. On the other hand, the delay time setter 26 is used to set the rise delay time t of the metering signal shown in FIG. The delay time t is the time it takes for this to become stable. Therefore, when the valve opening/closing signal A is input through the signal line 22, the clogging detection section 23 causes the weighing signal B to rise after the delay time t, and when the valve opening/closing signal A falls, the weighing signal B falls, and the period between the rises of the metering signal B is defined as the measuring time T of the paint flow rate. Further, the coefficient corrector 27 corrects the difference between the actual flow rate per unit pulse and the calculated value according to the viscosity of the paint, etc., and is usually set according to the type of paint. In this way, when the clogging detection section 23 receives the valve opening/closing signal A from the robot control section 19, the delay time setting device 26 changes the valve opening time according to the valve opening/closing signal A.
A metering signal is set with the time delayed by the delay time t as the metering time T, and during this period, the pulse signals inputted from the pulse transmitter 18 of the flowmeter 16 are counted, and the pulse signals set in the lower limit discharge amount setter 25 are set. When the paint flow rate falls below the lower limit discharge amount, the clogging signal shown in Figure 2 C is activated by the alarm 2.
8. Output to robot controller 19. When the robot controller 19 receives the clogging signal C, it outputs a stop signal to the robot body 4 and also controls the on-off valve 17.
A valve closing signal is output to the drive source 2 via the signal line 29, and a conveyor stop signal is output to the drive source 2 to stop the conveyor 1.
is configured to stop. In addition, when the clogging signal C is output during painting work on the object 3 to be coated, the robot body 4, conveyor 1, etc. are stopped after the painting of the object 3 being painted is completed to prevent uneven coating. It is made to do so. The coating robot according to the present invention has the above-described configuration, and while the object 3 to be coated is being conveyed by the conveyor 1, a robot operation signal is input from the robot control section 19 to the robot body 4 via the signal line 20. By this, the robot body 4 is operated, and by inputting a valve opening/closing signal A to the opening/closing valve 17 via the signal line 21, paint discharge control is performed. Now, set 60 as the measurement time in the measurement time setting device 24.
It is assumed that seconds are set and the lower limit discharge amount setter 25 is set to 7/min as the lower limit discharge amount.
Then, in 60 seconds, the measurement time T of the measurement signal RO
, the other non-metering time, and the paint flow rate measured during the metering time are assumed to have the relationships shown in Table 1 below.

[Table] In other words, 0.80 is measured in 6.9 seconds of measurement time,
After a non-metering time of 4.6 seconds has elapsed, 0.34 is measured again during a metering time of 3.2 seconds, and in the same manner, the total metering time is 31 seconds and the total paint flow rate is 3.25. In this case, the total discharge amount Q for 60 seconds is calculated as Q=3.25/31×60=6.29 (/min). Since this total discharge amount is less than the lower limit discharge amount of 7/min, it is determined that there is a clogging state, and the clogging detection section 23 outputs a clogging signal C. As a result, the clogging signal C is input to the alarm 28 to notify that the coating gun 12 has become clogged. At the same time, this signal C is transmitted to the robot control section 19.
A stop signal is output to the robot body 4, a valve close signal is output to the on-off valve 17, and a conveyor stop signal is output to the drive source 2 to stop the conveyor 1. Therefore, the operator only needs to replace the nozzle tip of the coating gun 12 and restart the coating operation. In addition, in the case of the example shown in Table 1, if the lower limit discharge rate is set as 0.12/second, the paint discharge rate q per second is q = 3.25/31 = 0.10 (/second), so in this case as well. The clogging detection section 23 can output a clogging signal C after the measurement time has elapsed. Further, although the painting gun 12 and the on-off valve 17 are illustrated as separate structures, the painting gun 12 and the on-off valve 17 may be assembled together, or the painting gun 12 may have a built-in valve mechanism. A painting gun may also be used. Furthermore, on-off valve 1
Although 7 is shown as a solenoid valve, it is of course possible to configure this as an air-driven switching valve for explosion-proof considerations. The painting robot according to the present invention is as described in detail above, and the paint flow rate is measured based on the period when paint is being discharged from the paint gun according to the signal from the robot control means, and the paint flow rate is set in advance. The paint flow rate input from the flowmeter during the measurement time is compared with a preset lower limit discharge amount, and when it is determined that the paint flow rate is below the lower limit discharge amount, a clogging signal is output. Even if the amount of paint flowing inside the pipe is minute, the presence or absence of clogging can be accurately detected. Moreover, since it measures the paint flow rate within the measurement time, it is possible to detect clogging of the paint gun even if the paint gun discharges paint intermittently, as in the case of undercoating. It has the advantage that it can be applied without any problem even when applying a high viscosity anti-corrosion paint to other surfaces.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of a painting robot according to the present invention, and FIG. 2 is a signal diagram. DESCRIPTION OF SYMBOLS 1...Conveyor, 2...Drive source, 3...Object to be coated, 4...Robot body, 11...Hydraulic power source, 12
... Paint gun, 13 ... Paint pipe, 14 ... Paint tank, 15 ... Pump, 16 ... Flow meter, 1
7... Opening/closing valve, 19... Robot control section, 23...
...Clogging detection unit, 24...Measurement time setting device, 25
... lower limit discharge amount setter, 26 ... delay time setter, 27 ... coefficient corrector, 28 ... alarm.

Claims (1)

[Scope of utility model registration request] A robot body operated by a signal from the robot control means, a painting gun provided on the robot body and discharging paint toward an object to be coated in response to a signal from the robot control means, and a paint gun for supplying paint to the paint gun. A painting robot consisting of a paint pipe connecting the paint gun and a paint source includes a flow meter installed in the middle of the paint pipe to measure the flow rate of paint supplied to the paint gun, and a measuring time. a lower limit discharge amount setting means for setting a lower limit discharge amount for each measurement time to be discharged from the coating gun; and a lower limit discharge amount setting means for the robot control means, a flowmeter, a measurement time setting means, and a lower limit discharge amount setting means. The robot control means measures the paint flow rate while the paint is being discharged from the paint gun according to a signal from the robot control means, and measures the paint flow rate input from the flow meter within the measuring time. A painting robot characterized by comprising a clogging detection means that outputs a clogging signal when the discharge amount falls below a lower limit discharge amount.