JPS6039428B2 - industrial robot - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an industrial robot, which detects clogging of a spray nozzle attached to the tip of an arm of the robot body by detecting pressure changes in a pipe suitable for the spray nozzle, and automatically detects clogging of the spray nozzle. The purpose is to provide an industrial robot that can stop spraying.

For example, industrial robots are sometimes used to paint workpieces that are continuously fed along a conveyor line.

This type of industrial robot has a spray nozzle attached to the tip of an arm of the robot body, and is configured to paint a workpiece while moving the arm vertically and horizontally according to a predetermined sequence. Generally, the paint flow path within this spray nozzle is extremely constricted, and therefore, the nozzle may become clogged with paint during continuous or intermittent use for a long period of time. However, in order to detect nozzle clogging, the above industrial robot has at least one observer standing near the robot body to monitor the painting process, and when the amount of paint being sprayed decreases, The robot was alerted to a clogged nozzle and stopped the robot. For this reason, conventional industrial robots are unable to fully automate painting work, and for example, if the change in the dispensed paint is not visually obvious, the supervisor may not notice that the spray nozzle is clogged. Variations in the coating result in uneven coating on the workpiece, resulting in poor finish and other drawbacks. The present invention eliminates the above-mentioned drawbacks, and an embodiment thereof will be described below with reference to the drawings.

Fig. 1 is a schematic configuration diagram of an embodiment of the industrial robot of the present invention, Fig. 2 is a circuit diagram of the main parts of its control device, and Fig. 3 is a diagram for explaining the signal waveforms of each part of the above circuit. show. In FIG. 1, an industrial robot 1 is constructed by attaching a spray nozzle 4 to the tip of an arm 2 of a playback type robot main body la via a wrist mechanism 3 so as to be rotatable in the vertical direction. be.

The arm 2 and wrist mechanism 3 of the robot main body la are supplied with hydraulic oil at a predetermined pressure from a hydraulic unit 5 through pipes 5a and 5b, respectively, to operate. The spray nozzle 4 is connected to a paint reservoir 7 through a pipe 6, and the paint supplied through the paint supply pipe 6 is sprayed from a paint injection port 4a at the tip of the nozzle 4.

A valve 8 is provided at the nozzle connection portion of the pipe 6, and the valve 8 is driven to open and close by air supplied to a valve driving section 8a. In the middle of the pipe 6, there is a pressure gauge 9 that indicates the pressure of the paint, and a manual valve 10 as a throttle mechanism that roughly adjusts the flow rate of the paint and keeps the pressure on the downstream side constant when the paint is being sprayed. A pressure switch 11, which will be described later, is provided. 1
2 is a pneumatic unit that connects the valve drive unit 8 via piping 13.
Working air is supplied to the atomizing air injection ports 4b formed around the paint injection port 4a through piping 14 to a, and air for pressure feeding the paint is supplied to the paint reservoir 7 via piping 15. supply. (It is a paint pressure type.) The pressure switch 11 is installed at the nozzle connection part of the paint supply pipe 6, and is activated when the pressure of the paint in the pipe 6 exceeds a predetermined constant value during paint atomization. Then, a clogging detection signal is output to a clogging detection circuit 17b, which will be described later.

Reference numeral 16 denotes a solenoid valve, which is provided in the valve driving air supply pipe 13 and is switched and driven by a signal from a control circuit 17a, which will be described later.

A control unit 17 includes a control circuit 17a, a clogging detection circuit 17b, etc., and the hydraulic unit 5, pneumatic unit 12, robot main body la, electromagnetic valve 16, etc. are drive-controlled by signals from the control circuit 17a. Ru.

The clogging detection circuit 170 is connected to the pressure switch 11, and receives a signal from the pressure switch 11 to operate the buzzer 18, lamp 19, etc., and also operates the control circuit 17.
A clogging detection signal is supplied to a. A workpiece 20 is an object to be painted, which is continuously conveyed by a chain conveyor or the like and is painted by a spray nozzle 4 at a predetermined working position.

In Figure 2, 21 is a DC stabilized power supply, and the push-down switch 22
It is connected to, for example, a commercial power source 23 via the push button switch 22, and when the push button switch 22 is closed, a constant DC voltage Vcc is supplied to each part in the control circuit 17a.

The inverter circuit 24 includes a resistor 25a and a capacitor 25b.
It is connected to the DC stabilized power supply 21 via a time constant circuit 25 consisting of a time constant circuit 25, and its output terminal is connected to one input terminal of a logical sum 26. The other input terminal of this OR 26 is connected via an inverter circuit 27 to one contact of a push-pin switch 28 for resetting the alarm circuit. The other contact of the push button switch 28 is grounded,
One of the contacts is connected to the DC stabilized power supply 21 via a resistor 29. The output terminal of the logical sum 26 is connected to the set terminals of the D-type flip-flop circuits 30 and 31, respectively, and to one input terminal of the alarm circuit 32.

The T input terminal of the flip-flop circuit 30 is connected to one contact of the pressure switch 11 through an inverter circuit 33. The other contact of the pressure switch is grounded, and the one contact is It is connected to the DC stabilized power supply 21. Furthermore, the D input terminal of the flip-flop circuit 30 is connected to the DC stabilized power supply 21, and the Q output terminal is connected to the other input terminal of an AND 36 whose one input terminal is connected to the output terminal of the inverter circuit 35. ing. The output terminal of the AND 36 is connected to the inverter circuit 37
It is connected to the T input terminal of the flip-flop circuit 31 via. The D input terminal of the flip-flop circuit 31 is connected to the DC stabilized power supply 21, and the Q output terminal is connected to one input terminal of the alarm circuit 32 and one input terminal of the AND 38.

The other input terminal of the AND 38 is connected to the output terminal of the inverter circuit 35 , and the output terminal of the AND 38 is connected to one input terminal of the relay circuit 39 . The other input terminal of the relay circuit 39 is connected to the DC stabilized power supply 21, and the pair of output terminals are connected to the commercial power supply 23 via the solenoid 16a of the electromagnetic valve 16. Next, the operation of the above-mentioned horizontal forming apparatus will be explained with reference to FIG.

When starting painting, the push button switch 22 is first pressed to close it in the position ``to'' in FIG.

When the pusher switch 22 closes, the DC stabilized power supply 21
is connected to the commercial power supply 23, and V is applied to each part in the control circuit 17a.
A DC voltage a of cc is applied. Therefore, the inverter circuit 24 is switched when a certain period of time Δt corresponding to the time constant of the time constant circuit 25 has elapsed, and its output becomes a low level (hereinafter referred to as "L"). When the output of the inverter circuit 24 becomes "L", the output b of the logical sum 26 becomes a high level (hereinafter referred to as "H"), and this reset pulse b from the logical sum 26 is applied to the flip-flop circuits 30 and 31.
is supplied to each of the IJ set input terminals and the reset input terminal of the alarm circuit 32, and each circuit 30, 31, 32 is reset. Here, when a switch (not shown) is opened to operate the robot body la at the nucleus t in FIG. is the logical product 36,
38.

At this time, one input terminal of the AND 38 is supplied with the "H" output terminal j from the flip-flop circuit 31, so when the signal d is supplied to the other input terminal, the output e of the AND 38 is becomes “L”. When the output e of the AND 38 becomes "L", a potential difference of Vcc is generated between the input terminals of the relay circuit 39, and the output terminals become conductive. When the relay circuit 39 is activated, the solenoid 16a of the solenoid valve 16 is energized and excited by the power source 23, and the solenoid valve 16 opens.

When the electromagnetic valve 16 opens, working air is supplied from the pneumatic unit 12 to the valve drive section 8a of the spray nozzle 4 via the pipe 13, and the valve 8 opens. When the valve 8 is opened, the paint in the paint reservoir 7 is forced through the pipe 6 by air supplied through the pipe 15, passes through the valve 8, and enters the paint injection port 4a.
The work is sprayed through two rivers. In this case, since the hydraulic unit 5 has already started operating when the switch for operating the robot body la is closed, the arm 2 of the robot body la swings from side to side within a predetermined angle range and starts working. 20, and the wrist mechanism 3 performs an operation of switching the direction of the soubre nozzle 4 from the upper side to the lower side one step at a time at the right and left swing turning points of the arm 2.

This ensures that the surface of the workpiece 20' is uniformly sprayed with paint before reaching the end of the painting section. Here, the flow rate and pressure of the paint passing through the paint supply pipe 6 depend on the air pressure in the paint reservoir 7, the throttle resistance value of the valve 10 in the pipe 6, and the diameter of the paint injection port 4a at the tip of the spray nozzle 4. However, as long as these pipe conditions do not change, the pressure switch 11
The pressure of the paint passing through remains unchanged.

Therefore, while the pressure switch 11 is open, the flow rate of the paint sprayed from the soubre nozzle 4 is constant, and the surface of the workpiece 20 is uniformly coated. Here, it is assumed that, for example, the paint injection port 4a of the spray nozzle 4 is clogged with paint, and the amount of paint sprayed is reduced.

In this case, as the paint becomes clogged, the pressure switch 1
It is assumed that the pressure of the paint passing through the cylinder 1 increases and the pressure switch 11 closes at the cylinder 1 in FIG. pressure switch 1
1 is closed, the input terminal of the inverter circuit 33 is grounded, and the signal f becomes "L". Therefore, the output signal g of the inverter circuit 33 changes from "L" to "H", a trigger signal is supplied to the T input terminal of the flip-flop circuit 30, and the flip-flop circuit 30 is set. As a result, the output h from the Q output terminal of the flip-flop circuit 30 changes from "L" to "H", the output of the AND 36 becomes "L", and it is further inverted by the inverter circuit 37 so that the "H" output i becomes the flip-flop. is supplied to the T input terminal of the pull-up circuit 31.

As a result, the output j from the Q output terminal of the flip-flop circuit 31 changes from "H" to "L", and this "L" output i is first supplied to the robot body la as an operation stop signal to the robot body la. .Also, at the same time “
L" output j is supplied to the AND 38, and the output e of the AND 38 changes from "L" to "H", so the relay circuit 39
The potential difference between the input terminals of the relay circuit 39 disappears, and the output terminals of the relay circuit 39 are opened.

Therefore, the solenoid 16a, which had been energized by the power source 23, is deenergized and demagnetized, and the solenoid valve 16 is instantaneously closed. When the solenoid valve 16 is switched, the supply of working air that had been supplied to the valve drive section 8a of the valve 8 is cut off, and the valve 8 is also instantaneously closed.

By closing the valve 8, the supply of paint via the paint supply pipe 6 is stopped, and the spray nostle 4 stops spraying the paint. or,
The output j of the flip-flop circuit 31 changes from “H” to “L”
As soon as the spray nozzle 4 is clogged, the alarm circuit 32 is activated and the buzzer 18, lamp 19, etc. are activated by the output k of the alarm circuit 32, so that the operator can reliably know that the spray nozzle 4 is clogged.

Here, when you know that the nozzle 4 is clogged by the sound of the buzzer 18 or the lighting of the lamp 19, press the push button switch 2.
8, the operation of the alarm circuit 32 can be stopped.

That is, by closing the pushbutton switch 28 at the time shown in FIG. b becomes "L" only while the push-fishing switch 28 is closed. As a result, the alarm circuit 32 is reset and the buzzer 1
8 and lamp 19 are deactivated. In the above embodiment, the spray nozzle 4 can spray not only paint but also other liquids.

Further, in the above embodiment, the alarm means such as the buzzer 18 and the lamp 19 may be installed outside the control unit 17.

As described above, the industrial robot of the present invention includes a robot body, a soubre nozzle attached to an arm of the robot body,
A liquid supply pipe for supplying liquid to the spray nozzle, a valve provided in the liquid supply pipe, a valve drive means for driving the valve to open and close, and a pressure sensor for detecting the pressure of the liquid in the liquid supply pipe. A pressure detector outputs a nozzle clogging detection signal when the pressure exceeds a predetermined constant value, and the pressure detector supplies the nozzle clogging detection signal to control the valve driving means to drive the valve in the liquid supply piping. It consists of a control device that opens the valve, so if it is applied to a painting device, for example, the pressure detector will operate as soon as the spray nozzle becomes clogged, without having to constantly monitor the amount of paint sprayed from the spray nozzle. The valve in the delivery pipe can be automatically closed, so clogging of paint can always be detected reliably and the painting operation can be stopped before uneven coating occurs, which enables more stable painting with a high labor-saving level. It has features such as being able to provide industrial robots as an industrial robot. In addition, by providing a valve in the spray nozzle, the device configuration can be simplified, and by using a liquid pressurized type for the atomizing liquid, the atomizing liquid can be extremely easily pumped by, for example, pressurized gas without using a pump or the like. Furthermore, by providing a pressure detector between the throttle mechanism installed in the liquid supply piping and the spray nozzle, the pressure detection sensitivity of the pressure detector can be variably adjusted by changing the size of the throttle mechanism. It has features such as being able to

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram of one embodiment of the industrial robot of the present invention, Fig. 2 is a circuit diagram of the main part of its control device, and Fig. 3 is a time chart for explaining signal waveforms of each part of the above circuit. It is. 1...Industrial robot, la...Robot body, 2
...Arm, 4...Spray nozzle, 6...Paint feed piping, 8.
... Valve, 8a... Valve drive unit, 11... Pressure switch, 17a... Control circuit. Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] 1. A robot body, a spray nozzle attached to an arm of the robot body, a liquid supply pipe for supplying a spraying liquid to the spray nozzle, and a liquid provided in the liquid supply pipe. a valve for spraying and stopping; a valve drive means for driving the valve to open and close; and a valve driving means for detecting the pressure of the liquid in the liquid supply pipe and outputting a nozzle clogging detection signal when the pressure exceeds a predetermined constant value. An industry comprising: a pressure detector; and a control device that receives a nozzle clogging detection signal from the pressure detector and operates the valve drive means to close a valve in the liquid supply piping. Robots for use. 2. The industrial robot according to claim 1, wherein the valve is provided in a spray nozzle. 3. The industrial robot according to claim 1, wherein the spraying liquid is a pressurized liquid type that is fed under pressure. 4. The industrial robot according to claim 1, wherein a throttle mechanism is provided in the liquid supply pipe, and the pressure detector is provided between the spray nozzle and the throttle mechanism.