JPS6345258B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an electrostatic coating device that coats objects to be coated conveyed to a conveyor in a coating booth while moving a coating machine up and down using a reciprocator. The present invention relates to an electrostatic coating device suitable for use when an object has a non-rectangular or non-rectangular parallelepiped painted surface whose area in the height direction is not uniform.

For example, when painting objects suspended from a conveyor in a circular painting booth using an electrostatic atomizer such as a disk type or bell type, the paint film is In order to equalize the
Conventionally, a method has been generally used in which the coating machine is supported by a reciprocator and the coating is carried out while moving the coating machine up and down.

However, with such conventional electrostatic coating equipment, it is possible to apply a uniform coating film to a rectangular or rectangular object that has a uniform coating area in the height direction. but,
It has been difficult to apply a uniform coating to a non-rectangular or non-rectangular object to be coated, where the coating area in the height direction is not uniform. For this purpose, multiple coats were applied to areas with large painting areas, but in order to automatically perform such multiple coats, a large number of limit switches were installed within the stroke range of the register locator, and the number of limit switches The reciprocator was to be reversed in the operating position. This method has the disadvantage that as the shape of the object to be coated becomes more complex, a large number of limit switches are required, and the positioning of each limit switch and the connection of the reciprocator to the drive device become extremely complicated. Ta. In addition, when objects with different shapes are transported to the same painting line, the overcoating range must be changed appropriately depending on the shape of each object, and this requires changing the arrangement of each limit switch. The drawback was that it required a tedious task. Moreover, since the painting line must be stopped while the above-mentioned work is being carried out, there is also the drawback that the painting efficiency is poor.

The present invention improves the drawbacks of the prior art as described above, and its feature is that the amount of paint discharged from the coating machine is made variable so that the coating machine can adjust the amount of paint according to the shape of the object to be coated. An object of the present invention is to provide an electrostatic coating device that can appropriately change the amount of paint discharged.

Embodiments of the present invention will be described below based on the drawings.

First, in FIG. 1, reference numeral 1 denotes a coating machine that electrostatically atomizes paint and sprays it onto an object to be coated.The paint 1 is supported by a reciprocator 2 so as to be movable up and down. Inside the reciprocator 2, there is provided a lifting mechanism 3 for lifting and lowering the coating machine 1, and an AC motor 5, such as a three-phase induction motor, which is connected to a sprocket 3A of the lifting mechanism 3 via a speed reducer 4. .

The reciprocator 2 is further equipped with an encoder 6, which transmits a pulse signal every predetermined displacement amount of the lifting mechanism 3, and the pulse signal from the encoder 6 is sent to a height calculation device 7.
is input. The height calculation device 7 calculates the height of the paint sprayer 1 from the reference position by inputting the pulse signal from the encoder 6. A detection device is configured. An absolute position calibration circuit 8 is attached to the height calculation device 7. The absolute position calibration circuit 8 constantly compares the signal output from the height calculation device 7 with its absolute position to prevent errors from being added to the input signal from the encoder 6 to the height calculation device 7. It is intended to prevent The height position signal of the paint sprayer 1 calculated by the height calculation device 7 is input to the comparison calculation device 9.

A paint discharge amount setting mechanism 10 is attached to the comparison calculation device 9, and the paint discharge amount setting mechanism 10 determines a predetermined height position from the reference position and the amount of paint at that position depending on the shape of the object to be coated. This is to set the discharge amount. The comparison calculation device 9 compares and calculates the height signal inputted from the height calculation device 7 with the paint discharge amount at each height position set in the paint discharge amount setting mechanism 10, and the paint sprayer 1 is set at a predetermined height. The comparison calculation device 9 and the paint discharge amount setting mechanism 10 form a paint control device.

Next, a paint discharge amount adjustment device 11 is connected to the comparison calculation device 9, and the paint discharge amount adjustment device 11 controls the supply of paint to the coating machine 1 based on the discharge amount control signal from the comparison calculation device 9. It is now possible to increase or decrease the amount. The paint discharge amount adjusting device 11 is composed of a paint pump 12, an electric motor 13 that drives the paint pump 12, and a rotation speed control circuit 14 that controls the rotation speed of the electric motor 13. The paint pump 12 has one end connected to the paint tank 15. It is provided in the middle of a paint pipe 16 whose other end is connected to the paint sprayer 1. Here, when the electric motor 13 is an AC motor, the rotation speed control circuit 14 makes the frequency variable based on the discharge amount control signal from the comparison calculation device 9, and an inverter is used to control the rotation speed of the electric motor 13. In addition, when the electric motor 13 is a DC motor, the rotation speed control circuit 14 makes the DC voltage variable based on the discharge amount control signal from the comparison calculation device 9, and a variable resistor or the like that controls the rotation speed of the electric motor 13 is used. used. Then, the paint discharge amount adjusting device 1
1 can adjust the amount of paint supplied from the paint tank 15 to the coating machine 1 by adjusting the rotation speed of the electric motor 13 as described above.

As shown in FIG. 2, the electrostatic coating device having the above-mentioned configuration is used to transport a workpiece suspended from a hanger 18 of a conveyor 17 in the direction of an arrow in the figure in a circular painting booth (not shown). A coating material 19 is coated.

Therefore, a case where the electrostatic coating apparatus according to the present invention is used to coat the object 22 having the shape illustrated in FIG. 2 will be described.

The object 19 to be coated has a triangular shape, and the surface to be coated becomes narrower upward from its lower end. When painting the object 19 having such a shape, if the reciprocator 2 is reversed along the trajectory shown in FIG. may be controlled as shown in FIG. 3B. That is, the amount of paint discharged from the sprayer 1 is maximized at the lower end position, and gradually decreases as the sprayer 1 moves upward, reaching the minimum amount at the upper end position. Then, when the reciprocator 2 is reversed and the sprayer 1 is lowered, the amount of paint discharged is gradually increased until it becomes maximum again at the lower end position.

When the object 19 to be coated is transported into the coating booth, paint is supplied to the coating machine 1 via the coating pipe 16, and high voltage is applied to start coating. At the same time, the reciprocator 2 is driven to raise the coating machine 1 from its lower end position. At the start of this painting, the rotational speed of the electric motor 13 is set to the maximum so that the pump 12 rotates at high speed. When the paint sprayer 1 is driven by the reciprocator 2 and starts to rise, its displacement is increased via the encoder 6. The data are input to the arithmetic unit 7 every moment. The height signal from this height calculation device 7 is input to a comparison calculation device 9, which is connected to a paint discharge amount setting mechanism 10.
A discharge amount control signal is output to the rotation speed control circuit 14 in order to discharge an amount of paint according to a predetermined setting value at each height position of the coating machine 1. As a result, the rotational speed of the electric motor 13 gradually decreases, and the amount of paint discharged from the paint pump 12 decreases. When the paint sprayer 1 is at the upper end position, the paint pump 12 is in the lowest discharge amount state, and the paint discharge amount of the paint sprayer 1 is the minimum. After that, when the reciprocator 2 is reversed and the sprayer 1 starts to descend, the displacement is inputted to the height calculation device 7 via the encoder 6, and the displacement is inputted to the height calculation device 7 via the comparison calculation device 9 based on the height signal. The discharge amount of the paint pump 12 of the paint discharge amount adjusting device 11 gradually increases, and the amount of paint discharged from the paint sprayer 1 gradually increases, and the discharge amount of the paint pump 12 reaches its maximum at the lower end position of the paint sprayer 1.

By controlling the amount of paint discharged as described above, the maximum amount of paint is supplied to the lower end portion having the largest coating area in the height direction of the object 22 to be coated, and gradually decreases as it goes upward. Since the amount of paint supplied at the upper end position is minimum, the coating film is uniform over the entire painted surface.

Furthermore, since the absolute position calibration circuit 8 is attached to the height calculation device 7, no error is added to the input signal to the height calculation device 7. Therefore, deviations in the stroke range of the reciprocator are prevented.

Note that the electrostatic coating device is capable of coating not only the surface of the object 19 facing the coating machine 1 but also a small amount in the depth direction at the same time, so that the stroke range of the reciprocator 2 is covered. If the height is set to be slightly larger than the height of the coating material 19, more efficient coating can be achieved. Further, the object to be coated is not limited to the shape shown in FIG. 2, but can also be applied to other shapes in which the coating area in the height direction is not uniform.
In this case, the paint discharge rate of the paint discharge rate setting mechanism 10 may be set in accordance with the shape of the object to be coated so that the coating film is uniform over the entire surface to be coated. Further, a paint pump 12, an electric motor 1
3. The rotation speed control circuit 14 has been described as being composed of the rotation speed control circuit 14, but the configuration is such that a regulator such as a flow rate adjustment valve is used, and control air is supplied to and discharged from the regulator, and the control air is used to control the regulator. It may also be configured to make the valve opening variable. Furthermore, although the encoder 6 has been described as a digital type that emits an incremental or absolute pulse signal proportional to the moving distance of the paint sprayer 1, it can be output as an analog signal using a potentiometer or the like, and the comparison circuit can be used. It may be of an analog type that is used to detect the height position of the sprayer.

As described in detail above, according to the electrostatic coating device according to the present invention, the height position of the coating machine that is movably supported by the reciprocator is detected by the height detection device, and the height signal is used to control the coating material. Since the paint discharge amount is input to the device and the paint discharge amount is changed by the paint discharge amount adjustment device based on the discharge amount control signal from the paint control device, it is possible to apply a coating of non-rectangular or non-cuboid shape with different coating areas in the height direction. By appropriately changing the amount of paint discharged in accordance with the increase or decrease in the coated area of the painted object, the coating quality can be significantly improved by making the coating film uniform over the entire painted surface. Moreover, since the height position of the sprayer is detected and the paint discharge amount of the sprayer is changed accordingly, the height position of the object to be coated and the paint discharge amount at each height position can be set in advance. The above-mentioned effects can be obtained by simply setting the amount of paint to be coated, and the amount of paint discharged can be set and changed extremely easily and quickly depending on the shape of the object to be coated. Further, for example, by storing setting values regarding a plurality of types of shapes in a microcomputer, objects of different shapes can be coated continuously.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an electrostatic coating device according to the present invention,
FIG. 2 is an external view showing an example of an object to be coated, FIG. 3A is a diagram showing the trajectory of the coating machine, and FIG. 3B is a diagram showing changes in the amount of paint discharged. 1... Painter, 2... Reciprocator, 6...
Encoder, 7...Height calculation device, 9...Comparison calculation device, 10...Paint discharge amount setting mechanism, 11...
Paint discharge amount adjustment device.

Claims (1)

[Claims] 1. A coating machine disposed in a coating booth to spray paint onto an object to be coated, a reciprocator that moves the coating machine up and down, a height detection device that detects the height position of the coating machine, and a A paint control device that outputs a paint discharge amount signal by comparing a signal from a height detection device with a paint discharge amount preset for each height position according to the shape of the object to be coated, and the paint control device an electrostatic coating device comprising: a paint discharge amount adjustment device that adjusts the paint discharge amount to the paint sprayer according to a signal from the paint sprayer;