JPS593226B2 - automatic spray gun - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a general automatic spray gun or an automatic spray gun for electrostatic painting in which the amount of paint ejected and the pattern width are digitally controlled in conjunction with automation of painting.

Currently, with the automation of painting, humans are no longer required to operate spray guns, and robots are now performing these functions.

However, digital control of the spray conditions (ejection amount, pattern width) was still far from perfect. The present invention was made in view of the above circumstances.

In other words, the control functions for automatic painting include the ON/OFF of the spray gun, the position, angle, and movement speed of the spray gun, but when examining the operation of handguns operated by humans, there are other functions in addition to the above functions. It turns out that the first part of the needle valve was unknowingly messed up and the amount of paint sprayed was adjusted. Further, the pattern width is adjusted by a pattern adjustment device as necessary. Of course, in order to perform more effective and advanced painting, strictly speaking, automatic guns also require this function, and the present invention digitally controls the amount of paint ejected in several preset steps. In addition, the present invention aims to provide an automatic spray gun that can adjust the pattern width by controlling the air pressure sent to the square air holes of the air cap and changing the amount of air jetted from the square air holes. Hereinafter, the present invention will be described with reference to drawings of embodiments.

First, as a specific configuration for controlling the spray gun, the first
As shown in the figure, it consists of an electric control system 1, an air control system 2, and a gun needle valve operating system 3.

Generally, the amount of paint ejected is changed by the opening degree (opening degree) of the needle valve at 25:00 when the paint pressurization pressure is constant. Therefore, the amount of paint ejected can be controlled by controlling the first generation of the needle valve, but with the form and shape of a normal nozzle needle, the first generation that changes the amount of ejection is 0 to 2n.
It is known that the amount of paint ejected remains unchanged and does not increase significantly even if the amount exceeds 2 mg L30. In the case of automatic guns, the function of pulling the needle valve is generally to move the piston by the inflow and pressure increase of operating air, and pull the needle valve accordingly.In this case, the needle valve 1 is pulled by changing the air pressure. It is possible to change the age. Theoretically, by knowing the spring constant, friction coefficient, and paint pressure of the spring that pushes the piston back when there is no working air, it would be possible to strictly control the working air pressure and change the displacement in an analog way. However, in reality, due to changes in each factor over time, changes in spring set state, fluctuations in paint pressure, difficulty in finely controlling air pressure, etc., it is necessary to control the delivery allowance to a predetermined value within the range of 0 to 2m71L. is difficult. The needle valve operating system of the present invention provides a stable displacement even when the above-mentioned factors change, and can digitally draw the displacement at the set position of the piston receiving plate.

In other words, the relationship between the air blowing pressure and the moving amount is shown in FIG. 2. Here, the values of Pal, pa2, and pa3 can be appropriately selected by changing the spring constants that press the piston and the piston receiving plate, and 11, 12, and 13 can also be appropriately set depending on the set position of the piston receiving plate. It becomes possible. First, the configuration of the automatic spray gun 4 will be explained. In the automatic spray gun 4, a needle valve 6 penetrates through the center of the gun body 4'', a piston 7 is fitted into the rear end of the needle valve 6, and the piston Tip cap 1 on the dorsal side of 7
Spring 8, 8 that restricts backward movement in stages is engaged with spring 9.
″, 8″ is installed. The spring 8, 8″, 8″
are set in a deflected state so as to have an initial load, and among these, two springs 8'', 8'' are positioned on piston receiving plates 21, 2 whose position is regulated by the stepped portion of the fixed guide 20.
12 is an air passage in the gun body 4''.

Further, the tip of the needle valve 6 faces the paint spout 13a of the paint nozzle 13, and an air cap 17 equipped with opposing square air holes 17a for pattern width adjustment is installed in front of the paint nozzle 13. . Reference numeral 14 indicates an air passage for pattern adjustment, and reference numeral 18 indicates a paint inlet.

Next, the operating air control circuit 5 of the automatic spray gun 4 in which the amount of paint ejected can be adjusted in stages will be explained as follows.

This air control circuit 5 has a spring constant of 3 to correspond to the spring constant of springs 8, 8', 8'' that gradually restrict a piston 7 disposed at the base end of a needle valve 6 penetrating through the center of the gun body 4''. Solenoid valves 9, 9'', 9'' are connected as an 0R circuit, that is, the solenoid valves 9, 9'', 9'' are connected in parallel with pressure reducing valves 10, 10゛, 10'' with relief in the front stage. As a connection,
This tip is connected to the air passage 12 (3rd
figure). Next, for example, if an electric signal A to obtain the first stage paint ejection amount is given to the air control circuit 5, the solenoid 9a of the solenoid valve 9 is energized and opened, and the signal is passed through the shuttle valve 11, 1'' to the gun body 4''. The piston 7 is moved by pressing the spring 8 corresponding to this air pressure, and the needle valve 6 set in the piston 7 is moved back by a predetermined amount, opening to the spout hole 13a of the paint nozzle 13 and spraying the paint. The paint that has flowed in from the passage 18 is spouted out.

Hereinafter, for the Pa2 value corresponding to the ejection amount of the next stage, the second
An electric signal of 1 is applied to the second solenoid valve 9'' to cause the piston 7 to
2 distance, and for the third ejection amount, the solenoid valve 9
” give another electrical signal to each needle valve 6 for the desired amount.
This is a setback. In addition, when performing pattern adjustment, the air pressure applied to the pattern adjustment air passage 14 is further controlled, and the air control circuit at this time is
As shown in the lower part of the figure, three solenoid valves 16, 16'', 16'' connected to the pressure reducing valves 15, 15'', 1D, respectively, are connected in parallel, and when a desired electric signal B is input, the corresponding solenoid valve 16
Or the square air hole 17 of the air cap 17 arranged at the tip of the gun body 4'', which adjusts the air pressure according to the operation of the gun body 4''.
A desired pattern is obtained by controlling the amount of air ejected from a.

In this pattern adjustment control circuit, compressed air escapes from the air hole at the end corner of the air cap, creating an open circuit, so a shuttle valve is not required. As described above, the automatic spray gun of the present invention is provided with a plurality of piston receiving plates in stages on the back of the piston provided at the rear end of the needle valve for regulating the retracted position of the piston. By arranging a spring set in a flexed state at the rear of the receiving plate, the retracted position of the piston can be regulated in stages by controlling the operating air pressure supplied to the piston.In other words, the retracted position of the needle valve can be regulated in stages. Since it can be controlled accurately, it is possible to accurately adjust the amount of paint ejected.

Moreover, is this invention a pneumatic system? By applying a sequence control to the electromagnetic valve operating signal of the system, the amount of paint ejected can be digitally controlled. In addition, when adjusting the pattern, the pattern opening can be automatically adjusted by directly controlling the amount of air ejected from the corner air hole of the air cap, similar to the automatic adjustment of the amount of paint ejected above, and the pattern opening can be automatically adjusted by directly controlling the amount of air ejected from the corner air hole of the air cap. This allows for operation.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; Fig. 1 is a flow sheet diagram showing the automatic adjustment system, Fig. 2 is an explanatory diagram showing the amount of movement of the piston part that operates the needle valve, and Fig. 3 is the air control system. The circuit diagram, FIG. 4, is a sectional view of the spray gun body. 1... Electric control system, 2... Air control system, 3... Gun needle valve operation system, 4...
Motion spray gun, 4″...Same gun body, 6″
...Needle valve, 7...Piston, 8,
8゛, 82...Spring, 9,9゛,9''・
... Solenoid valve for spray amount, 13 ... Paint nozzle, 16, 16゛, 16'' ... Solenoid valve for pattern, 17 ... Air cap, A , B...
·electoronic signals.

Claims (1)

[Claims] 1. In an air spray gun that changes the amount of paint sprayed by retracting a needle valve through the operation of a piston, a plurality of piston receiving plates are provided in stages at the rear of the piston to regulate the retracted position of the piston, and each piston receiving plate is A spring is placed at the rear, and the retracted position of the piston is regulated in stages by selecting the operating air pressure supplied to the piston.
An automatic spray gun that is characterized by the ability to adjust the amount of paint ejected in stages, as well as the pattern width by directly changing the air pressure fed into the air hole at the corner of the air cap.