JPH08215611A - Rotary atomization static coating device - Google Patents

Abstract

PURPOSE: To obtain a rotary atomization static coating device which reduces time necessary for washing the front of an atomizer head inner and the quantity of thinner. CONSTITUTION: A part 6c close to the outlet of a cleaning thinner passage 6 (outlet side passage) formed in the middle of an atomizer head inner 3 is formed to widen toward the end. More than one cleaning thinner passage is installed to shift the outlet 6a positions from each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary atomizing electrostatic coating device, and more particularly to a structure of a front cleaning thinner passage of an inner atomizing head.

[0002]

2. Description of the Related Art A rotary atomizing electrostatic coating apparatus is disclosed in Japanese Patent Laid-Open No. 6-1.
As disclosed in Japanese Patent 34354, FIG.
As shown in FIG. 11, the atomizing head 11 rotated at high speed is provided at the tip of the coating gun. The atomization head 11 includes a trumpet-shaped atomization head outer 12 and a substantially plate-shaped atomization head inner 13 attached to the inside of the atomization head outer 12. A nozzle 14 extends into the atomizing head 11 and enters the atomizing head 11.
The tip of the nozzle 14 faces the central portion of the back surface of the atomizing head inner 13. On the outer peripheral portion of the inner atomizing head 13, a plurality of holes 15 communicating from the rear surface 13b to the front surface 13a of the inner atomizing head 13 are provided at equal intervals in the circumferential direction. Further, a plurality of holes 16 communicating from the back surface 13b to the front surface 13a of the atomizing head inner 13 are provided at the center of the atomizing head inner 13 in the radial direction. The central hole 16 has a plurality of inlets because it is separated from each other on the back surface 13b of the inner atomizing head, so there are a plurality of inlets. Since it is extended so as to be focused on, the atomization head inner front surface 13a is gathered into one and opened, and the number of outlets is one.

During the execution of coating, the paint is sprayed from the nozzle 14 toward the central portion in the radial direction of the atomization head inner back surface 13b, and the sprayed paint is centrifugally applied to the atomization head inner back surface 13b and the outer peripheral portion. This hole 15
Through the inner front surface 13a of the atomizing head through the inner surface of the outer atomizing head 12 by the centrifugal force to reach the front end of the outer atomizing head 12 and then to the outer side in the radial direction by the shaping air. Electrostatically attracted to the work while adjusting the shape of the scattering. The air inside the splashed paint is dragged by the splashed paint and the inside of the splashed paint has a negative pressure, so that part of the misted paint is sucked inward and adheres to the atomization head inner front surface 13a. When changing colors, the nozzle 14
The thinner is sprayed from the inner side of the atomizing head inner surface 13b toward the center in the radial direction. The inner surface of the atomizing head outer 12 is washed out by passing to the front surface 13a side, and the remaining thinner is shown in FIG.
As shown in FIG. 1, the atomization head inner front surface 13a passes through the hole 16 in the central portion, and a part thereof is hung on the atomization head inner front surface 13a by the centrifugal force to cause the atomization head inner front surface 1a.
Wash 3a.

[0004]

The cleaning at the time of color change is required to be performed in a short time in order to improve the coating efficiency. Therefore, when the thinner pressure is increased to increase the thinner discharge amount from the nozzle, in the conventional structure, as shown in FIG. 11, the thinners passing through the plurality of passages 16 collide with each other at the opening 16a on the front side of the inner atomizing head. Then, the flow directions are vector-synthesized and directed forward on the atomizing head axis, that is, the radial component of the flow that was present when passing through the oblique passage 16 is canceled by the flow collision of the opening 16a. Only the flow component that remains is left and the thinner tends to flow forward, and the amount of thinner that flows along the atomizing head inner front surface 13a decreases. As a result, the time required for cleaning and the amount of thinner increase. An object of the present invention is to provide a rotary atomizing electrostatic coating device capable of reducing the cleaning time and the amount of cleaning thinner.

[0005]

The device of the present invention for achieving the above object is as follows. (1) In the rotary atomizing electrostatic coating device, which is provided with a passage for the inner surface of the atomizing head inner surface cleaning thinner that leads from the inner surface of the inner portion of the atomizing head to the front surface of the inner surface of the atomizing head, A rotary atomizing electrostatic coating device in which the shape of an outlet side passage to the front side of the inner surface of the atomizing head is widened toward the front surface of the inner surface of the atomizing head. (2) In the rotary atomizing electrostatic coating device, in which a plurality of passages for the inner surface of the atomizing head inner surface cleaning thinner are provided in the center of the inner portion of the atomizing head inner surface from the back surface of the inner atomizing head inner surface to the front surface of the inner atomizing head A rotary atomizing electrostatic coating device in which the positions of the outlets on the front side of the atomizing head inner side of the plurality of passages are shifted from each other.

[0006]

In the above-mentioned device (1), the shape of the outlet side passage to the front side of the inner atomizing head is formed into a divergent shape among the passages in the central part of the inner atomizing head. When passing through the outlet side passage part, it flows closely to the passage wall surface and becomes a divergent flow, so that it becomes a flow with a flow component that is directed radially outward and when it reaches the outlet of the passage, the atomization head axis From the flow path to the radial direction away from the inner side of the atomizing head, and the flow is expanded outward at the exit of the passage. as a result,
The time required for cleaning the front surface of the inner atomizing head and the amount of cleaning thinner are reduced. In the above-mentioned device (2), since the outlets of the passages through which the thinners pass are shifted, the cleaning thinners that have passed through the plurality of passages do not collide with each other at the outlets of the plurality of passages, and the cleaning thinners pass through the respective passages. The applied radially outwardly directed flow component exits the passage outlet while being retained without being lost by the collision. Further, since the plurality of passage outlets are separated from the atomization head axis in the radial direction, the cleaning thinner receives centrifugal force when exiting the passage outlet. Therefore, the cleaning thinner easily changes its direction toward the radially outward direction along the front surface of the inner atomizing head at the passage outlet. As a result, the time required for cleaning the inner surface of the atomizing head and the amount of cleaning thinner are reduced.

[0007]

1 to 7 show an embodiment of the present invention.
1 to 4 show a first embodiment of the present invention, and FIGS. 5 to 7 show a second embodiment of the present invention. The first of the present invention,
In the second embodiment, the components common to each other include the first,
The same reference numerals are given to both the second and third embodiments. First, a configuration common to the first and second embodiments of the present invention will be described with reference to FIG. 1, for example. Coating gun for electrostatic coating device (constitution of conventional coating gun, for example, JP-A-6-13435)
The atomizing head 1 is attached to the tip end of the structure disclosed in Japanese Patent Laid-Open No. 4) and is rotated at high speed around the atomizing head axis. The atomizing head 1 includes a trumpet-shaped atomizing head outer 2 and a substantially plate-shaped atomizing head inner 3 that is attached to the inside of the atomizing head outer 2. Inside the atomizing head 1, a nozzle 4
Is extending, and the tip of the nozzle 4 is the atomizing head inner 3
Faces the central portion of the back surface 3b. The nozzle 4 does not rotate, and sprays paint during coating and sprays a cleaning thinner during cleaning.

On the outer peripheral portion of the inner atomizing head 3, a plurality of holes 5 communicating from the back surface 3b to the front surface 3a of the inner atomizing head 3 are formed at equal pitches in the circumferential direction. The hole 5 is located at substantially the same position as the inner surface of the outer atomizing head 2, is inclined radially outward from the back surface 3b of the inner atomizing head 3 toward the front surface 3a, and when the paint is subjected to centrifugal force, The holes 5 are passed smoothly. A passage 6 of the atomization head front surface cleaning thinner is provided at a central portion in the radial direction of the atomization head inner 3 and extends from the back surface 3b to the front surface 3a of the atomization head inner 3. During the coating process, the atomizing head rotation speed is high and the air flows backward from the front surface 3a to the rear surface 3b, so that the paint does not flow into the passage 6.

Next, a specific structure of each embodiment of the present invention will be described. 1 to 4 in the first embodiment of the present invention.
As shown in FIG. 5, the passages 6 of the atomization head inner front surface cleaning thinner provided in the central portion of the atomization head inner 3 are opened at equal pitches around the central sharp portion 3c of the atomization head inner back surface 3b. Inlets 6f, and a plurality of inlet-side passages 6 extending obliquely inward from the plurality of inlets 6f toward the atomizing head axis
e, a single straight cylindrical straightening flow passage 6d extending forward on the atomizing head axis from a position where a plurality of inlet side passages 6e are converged at one point, and the atomizing head inner from the front end of the straightening flow passage 6d. A single outlet side passage 6c that extends to the front surface 3a and is formed in a divergent shape toward the atomization head inner front surface 3a.
And an R portion 6b that connects the inner surface of the outlet-side passage 6c and the atomizing head inner front surface 3a by bending, and the atomizing head inner front surface 3
a single outlet 6a opening at a. Exit side passage 6
Both c and the outlet 6a have the same axis as the atomizing head axis.

The number of inlet side passages 6e is 3 to 4, and the diameter of the inlet side passages is 1 to 1.2 mm. The reason is that a passage diameter of about 1 mm or more is required to smoothly pass the thinner, and a plurality of inlet openings 6f should be provided in the circumferential direction within the range of the diameter of the thinner ejected in a columnar shape from the nozzle 4. Then, the number of passages is 3 to 4, and the maximum diameter is about 1.2 mm. The diameter of the rectifying passage 6d is set to be larger than the diameter of each passage of the inlet side passages 6e so that the thinner flowing simultaneously from the plurality of inlet side passages 6e can pass therethrough, and the diameter of the flow passage 6d is about 1.5-2. It is set to 0.5 mm. The length of the rectifying passage 6d must be set to be equal to or longer than the length required for rectifying the diagonal flow of the thinner coming through the inlet side passage 6e into the flow in the atomizing head axis direction. To about 1 mm or more. The longer the length of the flow-regulating passage 6d, the more the flow-rectifying action, but if it is too long, the inner atomizing head 3
Since it does not fall within the range of thickness, it is set to about 1 mm.

The angle θ between the passage wall of the outlet side passage 6c and the atomizing head axis is set to 30 to 60 °. The reason is that if the angle θ is smaller than 30 °, the spread angle of the flow becomes too small, and when the thinner flow exits the outlet 6a, it becomes difficult for the flow to follow the atomizing head inner front surface 3a, and the angle θ becomes 60 °.
This is because if the value is larger, the thinner does not flow in close contact with the wall surface of the outlet side passage (the Coanda effect disappears) while flowing in the outlet side passage 6c, and it is meaningless to widen the outlet side passage 6c. The radius of curvature of the R portion 6b of the outlet 6a is set to about 1 mm or more. The reason is 1 mm
If it is smaller, when the thinner flow moves from the wall surface of the outlet side passage 6c to the inner front surface 3a of the atomizing head, it does not follow the inner front surface 3a of the atomizing head due to the edge effect of the corner, and is scattered obliquely forward as it is. Is.

In the second embodiment of the present invention, as shown in FIGS. 5 to 7, the passage 6 of the atomization head inner front surface cleaning thinner provided in the central portion of the atomization head inner 3 has the atomization head. A plurality of inlets 6f opening at equal pitch around the central sharp portion 3c of the inner back surface 3b, and the atomizing head inner front surface 3
A plurality of (same number as the inlet 6f) outlets 6a (however, the pitch circle diameter of the outlet 6a is smaller than the pitch circle of the inlet 6f) opened at equal pitches around the atomization head axis in a, and the inlet 6f and the outlet 6a. And a tangential passage 6g that communicates with and extends tangentially around the atomization head axis and obliquely inward in the atomization head axis direction.
And consisting of The outlets 6a of the passages are offset from each other,
One point is not concentrated. The outlet 6a of the passage is radially displaced from the atomizing head axis.

Next, the operation will be described. The first of the present invention,
The operation common to the second embodiment will be described. During the execution of coating, the paint is sprayed from the nozzle 4 toward the back surface 3b in the center of the atomizing head inner 3, and the sprayed paint passes through the atomizing head inner back surface 3b by the centrifugal force and forms a hole in the outer peripheral portion. 5
To the front end 3a of the atomizing head inner front 2a through the hole 5 and further to the front end of the atomizing head outer 2 by connecting the inner surface of the atomizing head outer 2 by the centrifugal force, and then outward in the radial direction. It scatters and is shaped by the shaping air to form a spray spray, and is electrostatically attracted to the work and adheres to the work. At the time of color change, the cleaning thinner is sprayed from the nozzle 4 toward the center of the atomizing head inner back surface 3b, and a part of the sprayed thinner reaches the outer peripheral portion through the atomizing head inner back surface 3b by centrifugal force. The inner surface of the outer atomizing head 12 is washed from the outer peripheral hole 5 to the inner side of the inner atomizing head 3a, and the remaining thinner passes through the hole 6 in the central portion to the inner front surface 3a of the atomizing head. Most of the inner surface 3a of the atomizing head is attached to the front surface 3a by centrifugal force.
To wash.

Next, the operation peculiar to each embodiment of the present invention will be described. In the first embodiment of the present invention, when the thinner passes through the passage 6 in the central part of the atomizing head, the thinners entering from the inlet 6f flow independently of each other in the inlet side passage 6e, but enter the straightening passage 6d. At the same time, they merge and are rectified by changing the direction of the flow toward the front along the atomizing head axis while flowing in the rectifying passage 6d. The thinner enters the outlet side passage 6c having a divergent shape from the flow straightening passage 6d, flows in close contact with the wall surface of the outlet side passage 6c while passing through the outlet side passage 6c, the direction of the flow changes to the diverging end, and the atomizing head The centrifugal force exerted on the thinner is increased by being radially separated from the shaft center. When the thinner reaches the outlet 6a, the angle between the divergent flow direction and the atomizing head inner front surface 3a is much smaller than 90 °, and the centrifugal force is applied to the thinner, so that the thinner easily flows. The direction is changed to the direction along the inner surface 3a of the atomizing head, and the inner surface 3a of the atomizing head is washed while flowing to the inner surface of the outer atomizing head. This thinner merges with the thinner that has passed through the hole 5 in the outer peripheral portion, reaches the front end of the atomizing head outer, and then scatters radially outward from there. The above tendency can be obtained regardless of the thinner pressure of the nozzle 4. Therefore, almost the entire amount of the thinner passing through the hole 6 in the central portion can be effectively used for cleaning the atomizing head inner front surface 3a, and the cleaning time can be shortened and the cleaning thinner amount can be saved.

In the second embodiment of the present invention, when the thinner passes through the passage 6 in the central part of the atomizing head, the thinner entering from the plurality of inlets 6f passes through the passages 6g independent from each other,
It flows out from the outlets 6a which are displaced from each other. Passage 6
While passing through g, the thinner is given a radial flow component to the atomizing head axis because the passage 6g is inclined with respect to the atomizing head axis. Further, since the outlet 6a is not concentrated at one point, it is separated from the atomizing head axis in the radial direction, and the thinner receives the centrifugal force at the outlet 6a portion. Therefore, the thinner easily redirects the flow at the outlet 6a in a direction along the inner front surface 3a of the atomizing head. in this case,
Since the outlets 6a are displaced from each other, the passage 6g
The flows that have passed through do not collide with each other, and the collision does not cancel out the radial components of the flow to form a forward flow. The thinner that has flowed along the inner front surface 3a of the atomizing head cleans the inner front surface 3a of the atomizing head, and eventually scatters radially outward from the front end of the outer atomizing head.
This tendency can be obtained regardless of the magnitude of the thinner pressure of the nozzle 4. Therefore, almost the entire amount of the thinner passing through the hole 6 in the central portion can be effectively used for cleaning the atomizing head inner front surface 3a, and the cleaning time can be shortened and the cleaning thinner amount can be saved.

[0016]

According to the apparatus of claim 1, among the cleaning thinner passages in the central portion of the inner atomizing head, the shape of the outlet side passage to the front side of the inner atomizing head is a divergent shape.
A radial outward flow component and centrifugal force can be applied to the cleaning thinner, and the thinner flow exiting the passage can be easily converted into a flow along the front surface of the atomizing head, and the cleaning time and the cleaning thinner amount can be reduced. According to the apparatus of claim 2, since the outlets of the cleaning thinner passage in the central portion of the inner atomizing head are shifted from each other, the thinner flowing through the plurality of passages is slanted. Exits the passage because the directional flows do not collide with each other and lose the outward radial component, and the outlet is away from the atomizing head axis rather than at one point and the flow receives centrifugal force. The flow of thinner can be easily changed to the flow along the front surface of the atomizing head, and the cleaning time and the amount of cleaning thinner can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of an atomizing head and its vicinity of a rotary atomizing electrostatic coating apparatus according to a first embodiment of the present invention.

FIG. 2 is a front view of a central portion of an inner atomizing head of FIG.

FIG. 3 is a cross-sectional view of the central portion of the atomizing head inner and its vicinity in FIG.

FIG. 4 is a cross-sectional view of the cleaning thinner flowing in FIG.

FIG. 5 is a front view of the central portion of the inner atomizing head of the rotary atomizing electrostatic coating device according to the second embodiment of the present invention.

FIG. 6 is a cross-sectional view of a central portion of the atomizing head inner shown in FIG. 5 and its vicinity.

FIG. 7 is a cross-sectional view showing a state in which a cleaning thinner is flowing in FIG.

FIG. 8 is a cross-sectional view of an atomizing head of a conventional rotary atomizing electrostatic coating device and its vicinity.

9 is a front view of the central portion of the inner atomizing head of FIG. 8. FIG.

FIG. 10 is a cross-sectional view of the central portion of the atomizing head inner and its vicinity in FIG.

FIG. 11 is a cross-sectional view showing a state where a cleaning thinner is flowing in FIG.

[Explanation of symbols]

 1 Atomizing Head 2 Atomizing Head Outer 3 Atomizing Head Inner 3a Atomizing Head Inner Front 3b Atomizing Head Inner Back 4 Nozzle 6 Atomizing Head Inner Front Cleaning Thinner Passage 6a Exit 6b R Part 6c Exit Side Passage 6d Rectifying Passage 6e entrance side passage 6f entrance 6g tangential passage

Claims (2)

[Claims] 1. A rotary atomizing electrostatic coating device, wherein a passage for an inner surface of an atomizing head inner surface cleaning thinner is provided in the center of the inner portion of the atomizing head, and the surface of the inner surface of the atomizing head is connected to the front surface of the inner portion of the atomizing head. Among these, the rotary atomizing electrostatic coating device is characterized in that the shape of the outlet side passage to the front side of the inner atomizing head is a shape that widens toward the front surface of the inner atomizing head. 2. A rotary atomizing electrostatic coating apparatus, wherein a passage for an inner surface of the atomizing head inner surface cleaning thinner is provided in the center of the inner portion of the atomizing head inner surface from the back surface of the inner surface of the atomizing head to the front surface of the inner surface of the atomizing head. A rotary atomizing electrostatic coating device, wherein a plurality of the plurality of passages are provided so that the outlets on the front side of the inner surface of the atomizing head are displaced from each other.