JPH0448820Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] The present invention relates to an electrostatic coating device that uses one rotating atomizer head to sequentially apply different colored paints to an object while changing colors. .

[Conventional technology]

In general, an electrostatic coating device rotates a rotating atomizing head at high speed and applies a high voltage to supply paint to the smooth surface of the rotating atomizing head to charge and atomize it, and this atomized charged paint The particles are applied to the object by flying along the lines of electric force formed between the particles and the object.

Then, once the painting is finished for a certain color,
Before painting the next color, it is necessary to use air and thinner to wash away the previous color paint that has adhered to the inside of the paint supply system from the color change valve device to the rotary atomizer head and on the rotary atomizer head. For this purpose, first, air is used to discharge the remaining paint in the paint supply system from the rotating atomizing head, and then thinner is used to clean the inside of the paint supply system and the smoothed surface of the rotating atomizing head. Repeat this process several times.

At this time, a large amount of pre-color paint, thinner, etc. flows out from the rotating atomizing head as waste liquid, but in order to prevent this waste liquid from scattering into the painting booth and contaminating the inside of the painting booth, the surrounding area of the rotating atomizing head must be placed. A cleaning shroud is provided so as to be retractable in the axial direction, and during the cleaning process, the cleaning shroud is advanced so as to surround the rotating atomizing head, and the previous color paint, thinner, etc. are collected as waste liquid by this cleaning shroud. It's getting old.

[Problem that the invention attempts to solve]

However, in the prior art described above, the cleaning shroud for collecting the waste liquid flowing out from the rotating atomizing head during the cleaning process is provided so that it can be retracted and retracted in the axial direction using an air cylinder or the like. During the cleaning process, the cleaning shroud, which had been retracted backwards, must be moved forward, and after cleaning is completed, it must be moved backwards again.

As a result, in order to move the cleaning shroud in and out of the axial direction during the cleaning process, it is necessary to supply and discharge control air to and from an air cylinder, etc., and operate the air cylinder, which increases the cleaning time by that amount. There is a problem with storing it away. For this reason, it is necessary to increase the distance between objects to be coated carried by a conveyor or the like, or to slow down the speed of the conveyor, which causes a reduction in the efficiency of the coating work.

The present invention was developed in view of the problems of the conventional technology, and most of the waste liquid such as pre-color paint and thinner produced during the cleaning process is collected in the waste liquid tank, and then transferred to the third paint passage and the hub member. By supplying air and thinner to the rotating atomizer head in spots to wash away the slight amount of previous color paint remaining on these parts,
To provide an electrostatic coating device which eliminates the need for a cleaning shroud and shortens cleaning time.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention provides a rotating shaft rotated by an air motor, an inner cylinder and an outer cylinder coaxially provided within the rotating shaft, and a proximal end formed within the inner cylinder. A first paint passage is formed between the inner cylinder and the outer cylinder and the first paint passage is connected to a color change valve device consisting of an air valve, a thinner valve, and a plurality of paint valves, and the proximal end is connected to a waste liquid tank via a waste liquid valve. a continuous second paint passage; a communication hole that communicates between the first and second paint passages on the distal end sides of the inner cylinder and the outer cylinder; and a communication hole provided coaxially on the distal end sides of the inner cylinder and the outer cylinder; The paint supply pipe has a third paint passage in the axial direction that communicates with the first paint passage, and a valve shaft that is inserted into the inner cylinder in the axial direction, and the proximal end of the valve shaft is connected to the valve. A paint supply valve that serves as an actuator and a valve body that opens and closes a third paint passage by seating the tip side on the valve seat of the paint supply pipe, and a paint supply valve that is fixed to the tip side of the rotating shaft and has paint on the inner circumferential surface. In an electrostatic coating device comprising a rotating atomizing head in which a smoothing surface is formed and the tip of the paint supply pipe is opened toward the paint smoothing surface, an electrostatic coating device is provided in which the paint smoothing surface of the rotating atomizing head is located midway through the paint smoothing surface. A hub member is provided, one side thereof serves as a paint supply surface in which a conical convex portion facing the tip of the paint supply pipe is formed, and a hub member in which an annular concave portion is formed at the center of the shaft on the other side; A plurality of first hub holes are drilled around the periphery of the member and allow the paint from the paint supply surface to flow out to the smoothing surface of the rotary atomizing head, and a first hub hole is provided in the center of the hub member from the conical convex side. A plurality of second hub holes are formed toward the annular recess side.

[Effect]

During the cleaning process, when the paint supply valve is closed and the waste liquid valve is opened, and air and thinner are supplied from the color change valve device, the previous color paint, thinner, etc. are transferred to the first paint passage, the communication hole, and the second paint. The waste liquid is collected through the passageway and the waste liquid tank into the waste liquid tank. Next, the paint supply valve is opened and the waste liquid valve is closed, and air and thinner are supplied from the color change valve device to the rotating atomizer head via the first paint passage and the third paint passage. , third paint passage;
Clean the hub member and rotating atomizer head. At this time, the third
There is only a small amount of pre-color paint remaining in the paint passage, and there is almost no paint attached to the rotating atomizer head, so these waste liquids are extremely small.
Since a cleaning shroud is not required and the thinner necessary for cleaning flows out from the second hub hole, the front surface of the hub member can be cleaned easily.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the figure, reference numeral 1 denotes a cylindrical rotating shaft, and the rotating shaft 1 is rotatably driven by an air motor 2 comprising an air turbine, an air bearing, or the like. Note that an air motor consisting of an air turbine, an air bearing, etc. is conventionally known, for example, from Japanese Patent Application Laid-open No. 115652/1983.

3 is an inner cylinder provided coaxially within the rotating shaft 1; 4 is an outer cylinder provided coaxially with the outer periphery of the inner cylinder 3; the inside of the inner cylinder 3 serves as a first paint passage 5; Outer cylinder 4
There is a second paint passage 6 between the first and
The distal end sides of the second paint passages 5 and 6 are connected to the inner cylinder connecting portion 13A of the paint supply pipe 13, which will be described later, in the radial direction, for example, by
They communicate through communication holes 7 that are drilled at certain locations. Here, the base end side of the first paint passage 5 is connected to a color change valve device 9 via a paint pipe 8, and the color change valve device 9 has N paint valves 9A of colors A to N. ~9
N, an air valve 9Ar, and a thinner valve 9Th. On the other hand, the base end side of the second paint passage 6 is connected to a waste liquid tank 11 via a waste liquid pipe 10, and a waste liquid valve 12 is provided in the middle of the waste liquid pipe 10. Note that the waste liquid valve 12 may be provided directly on the casing (not shown) of the coating machine.

Reference numeral 13 denotes a paint supply pipe which is located on the distal end side of the rotating shaft 1 and fixed coaxially to the distal ends of the inner cylinder 3 and outer cylinder 4.
A paint passage 14 is bored in the axial direction, and the paint passage 14 communicates with the first paint passage 5 via the inner cylinder connecting portion 13A. Further, on the base end side of the third paint passage 14, there is a valve seat 1 on which a valve body 16C, which will be described later, is seated.
5, the distal end of which protrudes into a rotary atomizing head 17, which will be described later. In addition, in the case of this example,
The third paint passage 14 has a diameter of 2 mm and a length of 15 mm, for example.
It is.

Reference numeral 16 indicates a paint supply valve, and the paint supply valve 16 has a valve shaft 16 inserted into the inner cylinder 3 in the axial direction.
A, a valve actuator 16B provided on the proximal end side of the valve shaft 16A, and a valve body 16C provided on the distal end side of the valve shaft 16A and seated on and off the valve seat 15. In the paint supply valve 16, the valve body 16C is always seated on the valve seat ₁₅ by the valve spring 16B1 of the valve actuator 16B, and control air is supplied to the valve actuator 16B. The body 16C is displaced to establish communication between the first and third paint passages 5 and 14.

Reference numeral 17 indicates a rotating atomizing head formed in a cylindrical or level shape, and the inner peripheral surface side of the rotating atomizing head 17 is connected to a rotating shaft having a female thread at one end with an axially intermediate rim 17A in between. 1, and the other end side becomes a smoothed surface 17C that expands into a morning glory shape, and the discharge edge of the smoothed surface 17C is carved with a large number of V-shaped grooves 17D, and the smoothed surface A hub member mounting groove 17E is formed in the middle of 17C.
The rotary atomizing head 17 is attached to the distal end side of the rotating shaft 1 via the attaching portion 17B, and in this attached state, the distal end of the paint supply pipe 13 is attached to the rim 1.
It extends to a slightly more protruding position than 7A. In the case of the embodiment, the rotating atomizing head 17 is formed as an ultra-small rotating atomizing head with an axial length of about 33 mm and a diameter of about 30 mm on the discharge edge side, and the V-shaped groove 1
7D has a length of approximately 1.0 to 3.0 mm, a depth of 0.2 to 0.4 mm,
The pitch is set at 0.2 to 0.4 mm to facilitate atomization.

Next, reference numeral 18 indicates a hub member that is formed into a substantially disk shape and is fitted into the hub member mounting groove 17E of the rotary atomizing head 17. The paint supply surface 18A is discharged and supplied, and the paint supply surface 18A has a conical convex portion 1 facing the tip of the paint supply pipe 13 at the axial center of the paint supply surface 18A.
8B is provided in a protruding manner, and the paint supplied from the third paint passage 14 is formed to easily spread along the conical convex portion 18B. On the other hand, the other surface side of the hub member 18 is a flat front surface 18C, and an annular recessed portion 18D is formed at the axial center of the front surface 18C, so that thinner flowing out from a second hub hole 20, which will be described later, is It is designed to give a dam effect.
Note that the diameter of the annular recessed portion 18D is approximately 6 to 7 mm.
The peripheral wall is formed into a tapered rising wall of approximately 20°.

Numerous first hub holes 19, 19, .
and each hub hole 19 has a rotating atomizing head 1.
It is bored at an inclination of, for example, 15° to 20° so as to be in contact with the smoothed surface 17C of No. 7 and communicate with both sides of the smoothed surface 17C.

Furthermore, 20, 20, . . . are four second hub holes with a diameter of 0.8 mm drilled in the center of the hub member 18, and one side of each hub hole 20 is connected to the paint supply surface 18A. It is located on one side and opens near the conical convex portion 18B, and the other side is an annular concave portion 18D in the front surface 18C.
It is open inward. The second hub hole 20 is formed with an inclination of, for example, 20 degrees so that the thinner can easily flow out.

In FIG. 1, numeral 21 is a shaping air ring having an annular nozzle hole 21A at its tip, which blows out shaping air during painting and color changes.
Further, 22 is a high voltage generator that applies a high voltage to the rotating atomizing head 17 via the rotating shaft 1.

The present embodiment is constructed as described above, and its operation will now be described with reference to FIG. 3.

First, in the painting preparation process, paint supply valve 1
The valve body 16C of No. 6 is seated on the valve seat 15 and closed, and the waste liquid valve 12 is also closed. On the other hand, although the high voltage generator 22 does not apply high voltage or blow out shaping air, the air motor 2
is driven to rotate, with a rotating shaft 1 and a rotating atomizing head 1.
7 has started rotating. In this state, when a paint control signal is supplied to the color change valve device 9 and, for example, the A color paint valve 9A is opened, the A color paint is transferred to the paint pipe 8, the first
The paint flows through the paint passage 5, the communication hole 7, and the second paint passage 6, and fills these interiors with paint.

Next, in the painting process, the high voltage generator 2
2, a high voltage of, for example, -90 kV is applied, and shaping air is supplied from the shaping air ring 21, a painting air control signal is supplied to the valve actuator 16B of the paint supply valve 16, and the valve shaft 16
The valve body 16C is moved to the left in the figure together with A, and the valve is opened to the state shown in FIG.

As a result, the A color paint in the first paint passage 5 flows out into the third paint passage 14 and is discharged toward the conical convex portion 18B of the hub member 18 provided in the rotary atomizing head 17. . The paint supplied to this conical convex portion 18B is caused by the high speed rotation of the rotating atomizing head 17.
The flow expands in the radial direction toward the paint supply surface 18A, passes through the first hub hole 19, flows toward the discharge edge of the smoothed surface 17C, and is sprayed as liquid threads from the V-shaped groove 17D, resulting in electrostatic mist. into charged particles. These charged particles fly along the lines of electric force between the rotary atomizing head 17 and the object to be coated, and are applied to the object to be coated.

A portion of the paint that has reached the conical convex portion 18B passes through the second hub hole 20 to the annular concave portion 18.
It also flows out from the flat front surface 18C to the smoothed surface 1.
Join us at 7C. However, since the paint has a high viscosity, the amount of paint flowing out from the second hub hole 20 is extremely small.

Furthermore, in order to spray the next color paint, for example, B color paint, the paint filled in the paint pipe 8, the first, second, and third paint passages 5, 6, 14, the rotary atomizing head 17, It is necessary to clean paint adhering to the hub member 18 and the like. This is the cleaning process.

Therefore, the supply of the painting air signal to the paint supply valve 16 is stopped and the valve body 16C is closed, and at the same time,
The waste liquid valve 12 is opened. In addition, high voltage generator 2
2. Stop the application of high voltage. In this state, a cleaning control signal is output to the color change valve device 9 to control the opening and closing of the air valve 9Ar and thinner valve 9Th alternately and repeatedly a plurality of times. As a result, the paint pipe 8, the first
The A color paint and cleaning thinner remaining in the second paint passages 5 and 6 are all collected into a waste liquid tank 11 via a waste liquid pipe 10 and a waste liquid valve 12.

Next, after cleaning the first and second paint passages 5 and 6, the inside of the third paint passage 14, the rotary atomizing head 17, the hub member 18, etc. are cleaned. For this reason,
An air control signal is supplied to the paint supply valve 16 to close the valve body 1.
Open the valve 6C, then open the thinner valve 9 of the color change valve device 9.
Only the valve Th is opened for a short time to supply cleaning thinner into the first and third paint passages 5 and 14 in spots.

As a result, the A color paint filled in the paint passage 14 is washed away by the thinner and the inside is cleaned, and the thinner discharged from the paint supply pipe 13 is transferred from the conical convex portion 18B of the hub member 18 to the paint. The smoothed surface 17C flows toward the V-shaped groove 17D via the supply surface 18A and the first hub hole 19, and is discharged after sufficiently washing these surfaces. Further, the thinner that has reached the conical convex portion 18B is removed from the second hub hole 20.
The flow flows into the annular recessed part 18D through the V-shaped groove 1 while cleaning the annular recessed part 18D and the front surface 18C.
It flows to 7D and is released.

According to this embodiment, the third paint passage 1
4 has a small diameter and a short length, so there is very little pre-color paint remaining in the paint passage 14, and the hub member 18, rotary atomizing head 17, etc. are continuously rotating at high speed. , the previous color paint is substantially free of adhesion. Therefore, since only a small amount of thinner is required for cleaning these, there is no problem even if the previous color paint and thinner are directly discharged from the rotary atomizing head 17 into the painting booth, and cleaning using conventional techniques The shroud for use can be abolished.
Note that 10 c.c. or less of thinner is sufficient for cleaning the third paint passage 14, rotating atomizing head 17, etc.
It is sufficient to supply it in spots.

Furthermore, since cleaning thinner has a lower viscosity than paint, the thinner discharged from paint supply pipe 13 to conical convex portion 18B of hub member 18 can sufficiently clean annular concave portion 18D and front surface 18C. amount is supplied through the second hub hole 20.
Therefore, the front side of the hub member 18 is also reliably cleaned.

Furthermore, since the hub member 18 is provided with an annular recess 18D at the center of its front surface 18C, the thinner flowing out through the second hub hole 20 is affected by the dam effect of the recess 18D, that is, the thinner is It has the effect of storing and discharging it evenly in all directions, and the front
C can be cleaned smoothly. Note that if the annular recess 18D is not provided, the thinner flowing out from the second hub hole 20 will flow as zero or one thinner flow due to centrifugal force, and the front surface 18C will not be cleaned. I can't wait.

In addition, in the case of the embodiment, the communication hole 7 is connected to the paint supply pipe 1.
Although it has been described as being provided in the inner cylinder connecting portion 13A of No. 3, it may be provided on the distal end side of the inner cylinder 3. Furthermore, although four second hub holes 20 are provided in the description, there may be three or five or more second hub holes 20.

[Effect of idea]

The electrostatic coating device according to the present invention is as described above in detail, and most of the waste liquid is collected in the waste liquid tank side, and the third paint passage, the rotating atomizing head, and the hub member are cleaned. Since only a small amount of thinner needs to be supplied in spots, the amount of pre-color paint and thinner discharged into the painting booth is extremely small, the interior of the painting booth is not contaminated, and a cleaning shroud can be eliminated. I can do it. Also, since the viscosity of thinner is lower than that of paint, the second
Thinner flowing through the hub hole can be supplied in an amount sufficient to clean the front surface of the hub member. Furthermore, since the annular recessed portion is provided in the central portion of the front side of the hub member, cleaning thinner can be uniformly supplied to the front surface due to the dam effect, and cleaning performance can be significantly improved.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view of the main part showing an embodiment of the present invention.
Figure 2 is a left side view of Figure 1 showing the rotating atomizing head;
FIG. 3 is an operation explanatory diagram showing painting and color changing operations. DESCRIPTION OF SYMBOLS 1... Rotating shaft, 2... Air motor, 3... Inner cylinder, 4... Outer cylinder, 5... First paint passage, 6...
Second paint passage, 7... Communication hole, 8... Paint piping, 9... Color change valve device, 9A to 9N... Paint valve,
9Ar...Air valve, 9Th...Thinner valve, 10...
Waste liquid piping, 11... Waste liquid tank, 12... Waste liquid valve, 13... Paint supply pipe, 14... Third paint passage, 15... Valve seat, 16... Paint supply valve, 16A
... Valve stem, 16B ... Valve actuator, 16C
... Valve body, 17 ... Rotating atomizing head, 17C ... Smoothing surface, 18 ... Hub member, 18A ... Paint supply surface, 18B ... Conical convex portion, 18C ... Front surface, 1
8D... Annular recessed part, 19... First hub hole, 2
0...Second hub hole, 22...High voltage generator.

Claims (1)

[Scope of utility model registration request] A rotary shaft rotated by an air motor, an inner cylinder and an outer cylinder coaxially provided within the rotary shaft, and formed within the inner cylinder, the proximal end of which consists of an air valve, a thinner valve, and a plurality of paint valves. A first paint passage connected to the color change valve device, a second paint passage formed between the inner cylinder and the outer cylinder and whose base end is connected to the waste liquid tank via the waste liquid valve, and a second paint passage connected to the inner cylinder and the outer cylinder. A communication hole that communicates between the first and second paint passages on the tip side of the cylinder, and a third paint passage that is coaxially provided on the tip sides of the inner cylinder and the outer cylinder and communicates with the first paint passage. It has a paint supply pipe extending in the axial direction, and a valve shaft inserted into the inner cylinder in the axial direction, the base end of the valve shaft serving as a valve actuator, and the distal end thereof serving as a valve seat of the paint supply pipe. A paint supply valve that is seated apart and serves as a valve body for opening and closing a third paint passage; and a paint supply valve that is fixed to the tip side of the rotating shaft and has a paint smoothing surface formed on its inner peripheral surface; In an electrostatic coating device comprising a rotating atomizing head with an open end of the paint supply pipe,
The rotary atomizing head is provided in the middle of the paint smoothing surface, with one side serving as a paint supply surface having a conical convex portion facing the tip of the paint supply pipe, and the other side having an annular concave portion at the center of the shaft. a hub member having a recess formed therein; a plurality of first hub holes drilled around the periphery of the hub member to allow the paint from the paint supply surface to flow out to the smoothed surface of the rotary atomizing head; An electrostatic coating device comprising a plurality of second hub holes drilled in the center of the hub member from the conical convex side to the annular concave side.