JP2879284B2 - Paint discharge control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paint discharge amount control apparatus using an air operated pressure reducing valve used for automatic control of a paint discharge amount from a spray gun in an automatic coating machine (reciprocator, robot). .

[0002]

2. Description of the Related Art Conventionally, an automatic coating system as shown in FIG. 4 has been known. A spray gun 12 at the end of the arm of the robot 11 and an air operated pressure reducing valve 1 for controlling the amount of paint discharged from the spray gun 12
3 are provided. The paint is pumped up by a pump 15 and supplied to the spray gun 12 via a paint hose 14. The pressure of the air supplied from the compressor 18, which is an air supply source, is controlled by the control device 17 and supplied to the air operated pressure reducing valve via the air tube 16.

A control device 17 for controlling the discharge amount of the paint from the spray gun 12 by the air operated pressure reducing valve 13 is configured as shown in FIG. 5, for example. Air pressure reducing valves 21a and 21b are provided on the high pressure output side and the low pressure output side of the air supply source, respectively. These air pressure reducing valves 2
The air decompressed in 1a, 21b is supplied to two-way solenoid valves 22a, 22a.
2b selectively supplies the air to the air tube 16 connected to the air operated pressure reducing valve.

FIG. 5A shows a state in which the high-pressure side solenoid valve 22a is on and the low-pressure side solenoid valve 22b is off. At this time, the high-pressure side air (pressure P1) reduced by the air pressure reducing valve 21a is supplied to the air tube 16. FIG. 5B shows a state in which the high-pressure side solenoid valve 22a is turned off and the low-pressure side solenoid valve 22b is turned on. At this time, the air pressure reducing valve 21b
Is supplied to the air tube 16 on the low pressure side (pressure P2).

As described above, the paint secondary pressure changes by switching the operating air pressure, and the paint discharge amount from the spray gun 12 is switched and controlled. FIG. 6A shows a response characteristic of the operating air pressure in such a conventional control method. FIG. 6B shows a change in the pattern width sprayed by the paint whose discharge amount is controlled by the operating air pressure.

[0006]

In the conventional control system for a paint pressure reducing valve as described above, the two solenoid valves 22a and 22b are turned on and off in a complementary manner as shown in the response characteristic of FIG. Switching of the operating air pressure is performed at low pressure P2.
The switching from the high pressure P1 to the high pressure P1 is smooth, whereas the switching from the high pressure P1 to the low pressure P2 takes time. This corresponds to the state of the operating air pressure P1 (FIG. 5).
(A)), the state of the operating air pressure P1 (FIG. 5)
This is because the air in the air tube 16 must be exhausted through the low pressure side air pressure reducing valve 1b when switching to (b)). The loss of the switching time makes it difficult to rapidly change the spray pattern width as shown in FIG.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a paint discharge amount control device with improved responsiveness of operating air pressure switching.

[0008]

Means for Solving the Problems A paint discharge amount control device according to the present invention comprises first and second air pressure reducing valves provided on a high pressure output side and a low pressure output side of an air supply source, respectively. A shuttle valve connected to an air tube communicating with the air operated pressure reducing valve for selectively supplying air depressurized by the first and second air pressure reducing valves to the air operated pressure reducing valve; The on / off control of the supply of the air depressurized by the first air pressure reducing valve to the shuttle valve by an electric signal is provided between the valve and the first air pressure reducing valve on at least the high pressure side. A three-way solenoid valve for exhausting air into the air tube.

[0009]

According to the present invention, when the three-way solenoid valve is turned on, the air on the high pressure side passing through the first air pressure reducing valve passes through the three-way solenoid valve and the shuttle valve having a high-pressure circuit selecting ability. It is supplied to the air tube. When the three-way solenoid valve is turned off, the supply of air on the high pressure side is stopped, and the residual air in the air tube is exhausted from the exhaust port of the three-way solenoid valve via the shuttle valve. Since this exhaust does not pass through the air pressure reducing valve, it is performed at a higher speed than before.

When the air pressure in the air tube becomes lower than the air pressure at the output of the second air pressure reducing valve on the low pressure side, the shuttle valve is switched, and the air on the low pressure side passing through the second air pressure reducing valve is released. The air is supplied into the air tube via the shuttle valve.

As described above, according to the present invention, by combining the three-way solenoid valve having the exhaust port and the shuttle valve, the exhaust speed of the residual air when switching the operating air pressure from the high pressure state to the low pressure state can be increased. . As a result, the time loss of switching from high pressure to low pressure is reduced, and for example, even during spraying of the paint, the paint discharge amount and the pattern width can be changed according to the location of the object to be coated.

[0012]

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a configuration of a control device of an air operated type paint pressure reducing valve according to one embodiment of the present invention.
(A) shows a high-pressure air supply state, and (b) shows a low-pressure air supply state.

As shown, a first air pressure reducing valve 1a is provided on a high pressure output side of an air supply source, and a second air pressure reducing valve 1a is provided on a low pressure output side.
The air pressure reducing valve 1b is provided. The first air pressure reducing valve 1a is connected to the air tube 3 connected to the air operated pressure reducing valve.
A shuttle valve 2 having a high-pressure circuit selection function is provided at a branch point in order to selectively switch and supply high-pressure air passing through and low-pressure air passing through the second air pressure reducing valve 1b. Shuttle valve 2 controls switching of high pressure air
And a three-way solenoid valve 4 provided between the high-pressure side first air pressure reducing valve 1a. The three-way solenoid valve 4 has three functions: on / off of air supply by an electric signal and exhaust.

The operation of the present invention configured as described above will be described. First, FIG. 1A shows the state when the three-way solenoid valve 4 is energized, and FIG. 1B shows the state when the three-way solenoid valve 4 is not energized. When the three-way solenoid valve 4 is energized, as shown in FIG.
a and the shuttle valve 2 are connected. At this time, the high-pressure air (air pressure P1) passing through the first air pressure reducing valve 1a and the second air
The low-pressure air (air pressure P2) passing through the air pressure reducing valve 1b is supplied to both ends of the shuttle valve 2 at the same time.
Will be supplied.

When the three-way solenoid valve is turned off, the supply of high-pressure air is turned off, the residual air in the air tube 3 is connected to the exhaust port of the three-way solenoid valve 4 via the shuttle valve 2, and exhaust starts. When the residual air pressure P1 'becomes P1'<P2 + Pk (Pk is a constant) with respect to the air pressure P2 on the low pressure side, the shuttle valve 2 switches as shown in FIG. 1 (b), and the second air pressure reducing valve 1b Side low pressure air is supplied to the air tube 3 via the shuttle valve 2. Since the exhaust through the three-way solenoid valve 4 has less resistance than that through the conventional air pressure reducing valve,
The switching of the air supply is performed at a high speed.

When the three-way solenoid valve 4 is energized again, if there is a relationship of P1> P2 + Pk between the high-pressure side air pressure P1 and the low-pressure side air pressure P2, the shuttle valve 2 is switched, and the high-pressure air is again supplied. Supply is made.

FIG. 3 shows the responsiveness of the operating air pressure according to this embodiment, and how the paint pattern changes due to the change in the air pressure. As is clear from comparison with FIG. 6 of the related art, the change from the operating air pressure P1 to P2 is performed at a very high speed. As a result, the time required for changing the amount of paint discharged from the spray gun, and hence for changing the spray pattern width, is reduced. This shortens or eliminates the time required to turn on and off the spray gun for switching the discharge amount in conventional robot painting, etc., according to the location of the workpiece during spraying only by switching the operating air pressure The pattern width can be changed, and the loss of coating time can be reduced.

FIG. 2 shows a control device for an air operated pressure reducing valve according to another embodiment of the present invention. The difference from the embodiment shown in FIG. 1 is that the shuttle valve 2 and the first air pressure reducing valve 1a are different.
And a three-way solenoid valve 4a is provided between the shuttle valve 2 and the second air pressure reducing valve 1b.
b.

In the case of this embodiment, two three-way solenoid valves 4
a and 4b are complementarily turned on and off. FIG. 2 (a)
Shows a state in which the three-way solenoid valve 4a on the high pressure side is energized and the three-way solenoid valve 4b on the low pressure side is de-energized. FIG. 2B shows a state where the three-way solenoid valve 4a on the high pressure side is de-energized and the three-way solenoid valve 4b on the low pressure side is energized. The switching operation of the air supply is basically the same as in the previous embodiment.

In this embodiment, when switching from the low-pressure air supply state (FIG. 2B) to the high-pressure air supply state (FIG. 2A), the low-pressure side three-way solenoid valve 4b is in the exhaust state. The switching from the low-pressure air supply state to the high-pressure air supply state does not have a problem without forcibly exhausting the residual pressure of the air tube 3 as described in the previous embodiment. Since the electromagnetic valve 4b performs forced exhaust, switching of the shuttle valve 2 is further accelerated.

In the above embodiment, the control of the automatic coating is exclusively described, but the present invention can be similarly applied to a thinner cleaning system. In recent years, when there are many color changes in automobiles, thinner cleaning can be performed smoothly by controlling the thinner and discharge rate by controlling the air operated pressure using the same automatic control system for thinner cleaning. It becomes possible.

[0022]

As described above, according to the present invention,
By combining a three-way solenoid valve with an exhaust port and a shuttle valve, switching time loss when switching the operating air pressure from a high pressure state to a low pressure state is reduced. A paint discharge amount control device capable of changing the discharge amount and the pattern width can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing a control device of an air operated type paint pressure reducing valve according to one embodiment of the present invention.

FIG. 2 is a diagram showing a control device of an air operated type paint pressure reducing valve according to another embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a response of an operating air pressure and a pattern width change according to the embodiment of FIG. 1;

FIG. 4 is an explanatory view showing an automatic coating system.

FIG. 5 is an explanatory diagram of a conventional control device for an air operated paint pressure reducing valve.

FIG. 6 is an explanatory diagram showing the response of the operating air pressure and the pattern width change in the apparatus of FIG. 5;

[Explanation of symbols]

 1a first air pressure reducing valve 1b second air pressure reducing valve 2 shuttle valve 3 air tube 4, 4a, 4b three-way solenoid valve

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B05B 12/00-12/14 B05B 7 / 12,7 / 24 B05C 11/10

Claims (1)

(57) [Claims] 1. An apparatus for controlling a discharge amount of a paint using an air operated pressure reducing valve, comprising: a first and a second pressure reducing means for reducing an air pressure provided on a high pressure output side and a low pressure output side of an air supply source, respectively. 2 air pressure reducing valve and an air tube communicating with the air operated pressure reducing valve for selectively supplying air depressurized by the first and second air pressure reducing valves to the air operated pressure reducing valve. A shuttle valve, provided between the shuttle valve and at least the first air pressure reducing valve on the high pressure side, to turn on the supply of the air depressurized by the first air pressure reducing valve to the shuttle valve by an electric signal; A paint discharge amount control device, comprising: a three-way solenoid valve for performing off control and exhausting the inside of the air tube when off.