JPH0446820Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an air-driven bell-type atomizer, and particularly to a system for maintaining a constant bell rotation speed during coating.

Prior Art and its Problems Painting machines that electrostatically atomize paint using a bell that rotates at high speed using air as a driving source are widely used in the automobile industry and other various industrial fields. However, in this main bell-type atomizer, even if the paint discharge amount, air amount, and air pressure are held constant and the painting operation is started, the amount of paint adhering to the bell remains unchanged for a while after the start of painting. , which gradually increases over time, causes fluctuations in the number of rotations of the bell between the start and end of painting. Figure 2 shows a graph of the relationship between the number of rotations of the bell and the elapsed time after dispensing the paint.
In the case of cc/min, the bell rotation speed will return to the original speed after 60 seconds after dispensing, as shown by the broken line.
It gradually decreases from 15,000 rpm to 13,000 rpm, and in the case of a discharge rate of 300 c.c./min, it gradually decreases from 15,000 rpm to about 10,000 rpm at first, as shown by the same dot-dashed line. Such fluctuations in the rotational speed of the bell change the atomization and atomization state of the paint, and when applied to the painting of the body of an automobile, for example, the color tone differs between the front and rear parts, causing a kind of uneven paint. Furthermore, since the color of each part of the body is different, it is inconvenient that block repairs cannot be performed.

One way to solve this problem is to delay the start of the painting process until after the paint has been discharged onto the bell, the amount of paint adhered to the bell is approximately constant, and therefore the number of rotations of the bell is constant. However, this results in a loss of working time and paint, and is not a preferred solution.

The present invention was made with the aim of eliminating such conventional problems.

Means for Solving Problems The present invention aims to replace the bell drive air supply system with the main air supply in a paint sprayer that electrostatically atomizes paint using a bell that rotates at high speed using air as the drive source. The auxiliary air supply system is equipped with a solenoid valve, and between the solenoid valve and the bell, the rotation speed of the bell is adjusted. A detector for detection and a detection signal received from the detector are compared with a data signal corresponding to the input reference rotation speed in advance, and the detection signal <
This air-driven bell-type atomizer is characterized in that it is equipped with a comparator that issues a command to open the electromagnetic valve when the data signal is detected, and to close the electromagnetic valve when the detection signal is equal to the data signal.

Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings.

In the figure, 1 is a bell in an air-driven bell-type atomizer, and 2 is an air pipe for supplying air as a driving source to the bell 1, and the air is supplied from the air pipe 2. By rotating the bell 1 at high speed, the paint supplied to the bell 1 is electrostatically atomized. This configuration itself is completely different from conventional coating machines of this type. Note that the paint supply system is omitted from the figure.

The present invention provides a coating machine of the above type having two air supply systems, a main air supply system 3 and an auxiliary air supply system 4, and a solenoid valve 5 provided on the auxiliary air supply system 4. Furthermore, a detector 6 for detecting the rotation speed of the bell 1 is provided between the electromagnetic valve 5 and the bell 1, and a detection signal received from the detector 6 is set to an input reference rotation speed (for example, 15000 rpm) in advance. A comparator 7 is installed which compares the data signal with a matching data signal and issues an instruction to open or close the electromagnetic valve 5. The comparator 7 is configured to issue a command to open the electromagnetic valve 5 when the detection signal<data signal, and issue a command to close the electromagnetic valve 5 when the detection signal≈data signal. In addition, 3a is a regulator provided on the main air supply system 3, and 4a is a regulator provided on the auxiliary air supply system 4.

In the coating machine of the present invention having the above-mentioned configuration, at the time of starting coating, that is, when the bell 1 is maintaining the reference rotation speed (for example, 15000 rpm) as shown in FIG. a detection signal from 6;
There is no substantial difference between the data signals previously input to the comparator 7, and the comparator 7 is connected to the electromagnetic valve 5.
is instructed to close. Therefore, air assistance to the main air supply system 3 is not performed at the time of starting this coating.

As time elapses after the start of dispensing paint, the rotational speed of the bell 1 decreases as shown in FIG. When a difference occurs,
The comparator 7 issues a command to open the electromagnetic valve 5, and the auxiliary air joins the main air, causing the bell 1 to open.
The rotation speed of will increase.

When the rotational speed of the bell 1 becomes substantially equal to the reference rotational speed, there is no substantial difference between the detection signal and the data signal, and therefore the comparator 7
A command is issued to close the auxiliary air, and the supply of auxiliary air stops. By repeating the command to open and close the electromagnetic valve 5 by the comparator 7, the rotation speed of the bell 1 is maintained at a substantially constant rotation speed as shown by the solid line in FIG.

Effects According to the paint sprayer of the present invention, the number of revolutions of the bell is maintained substantially constant from the start of painting to the end of painting, so the color is stable, the condition of the painted surface is uniform, and the quality of the paint film is improved. In addition to contributing to improvement, since the color tone becomes uniform in all parts, there are advantages such as making it possible to repair blocks. Furthermore, since the number of revolutions of the bell can be maintained constant without being affected by the type of paint or comparative differences between paints, it can be applied to a wide range of paint applications.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram schematically showing an embodiment of the present invention, and FIG. 2 is a graph showing the relationship between the number of rotations of the bell and the elapsed time after the paint is discharged. In the figure, 1 is a bell, 2 is an air pipe, 3 is a main air supply system, 4 is an auxiliary air supply system, 5 is an electromagnetic valve, 6 is a detector, and 7 is a comparator.

Claims (1)

[Scope of utility model registration request] In a paint sprayer that electrostatically atomizes paint using a bell that rotates at high speed using air as the drive source, the bell drive air supply system is connected to the main air supply system, and air is supplied to the main air supply system as appropriate. Auxiliary air supply system 2
The auxiliary air supply system is equipped with a solenoid valve, and between the solenoid valve and the bell, there is a detector for detecting the rotation speed of the bell, and a detection signal received from the detector is inputted in advance. The air drive is characterized by installing a comparator that issues a command to open the electromagnetic valve when the detection signal is less than the data signal, and to close the same when the detection signal is equal to the data signal, compared with a data signal corresponding to the reference rotation speed. Type bell type paint machine.