JP2000325836A - Electrostatic coating equipment - Google Patents

Abstract

(57) [Problem] To improve the sealing performance of a valve mechanism which is detachably attached at the time of electrostatic coating and to improve the durability. A first on-off valve (44) includes a needle (66) and a valve seat (70). The valve seat (70) contacts a spherical body (72) and a seat holding the metal seat (74). A holder 76 and a holder guide 80 for holding the metal sheet body 74 and the sheet body holder 76 so as to be able to advance and retreat in an axial direction and a direction orthogonal to the axial direction are provided. The holder guide 80 has a function of aligning the metal sheet 74 with the sphere 72 by being screwed into the screw hole 78 and further fixing the metal sheet 74.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic coating apparatus for supplying a conductive paint to a coating gun through a paint supply path to perform electrostatic coating.

[0002]

2. Description of the Related Art In general, an electrostatic coating apparatus for a conductive paint is configured such that a conductive paint is supplied from a paint supply source via a paint supply path to a coating gun to which a high voltage is applied.
The work is configured to perform electrostatic coating.
For this reason, it is necessary to electrically insulate the coating gun from the paint supply source during electrostatic coating by the coating gun.

In view of the above, there is known an electrostatic coating apparatus for a conductive paint in which a paint supply path connecting a paint supply source and a coating gun can be separated along the way with an insulating distance therebetween (for example, there is known an apparatus for electrostatically coating a conductive paint). , EP 0 467 626 A1).

The above-mentioned electrostatic coating apparatus is provided with a connection mechanism for separating the paint supply path along the way. The connection mechanism includes a first connection portion provided on the paint supply source side and a coating gun side. And a second connection portion provided at
First and second on-off valves are formed in the first and second connection portions.

[0005] The first and second connection portions are configured to have a male structure on one side and a female structure on the other side, and can be connected to each other with sealing means such as an O-ring interposed therebetween. The first and second connection portions are separated from each other to close the first and second on-off valves to prevent the paint from leaking, while being connected to each other, the first and second on-off valves are closed. Is open, so that the paint can be distributed.

[0006]

However, according to the above-mentioned prior art, if the attaching and detaching operations of the first and second connecting portions are repeated tens of thousands of times, the opening and closing operations of the first and second on-off valves also become inconvenient. This has been repeated tens of thousands of times, and it has been pointed out that there is a problem that the seal portions of the first and second on-off valves are damaged and paint leaks from the seal portions. As a result, a high voltage cannot be applied to the conductive paint, and a paint failure occurs, or color mixing occurs between a paint of a previous color and a paint of a new color that has undergone paint leakage during color change. There are problems such as. Therefore, measures have been taken to increase the manufacturing accuracy of the first and second on-off valves, but there is a problem that the durability of the seal portion is not sufficient and the cost increases.

An object of the present invention is to solve this kind of problem and to provide an electrostatic coating apparatus having a simple structure, effectively improving sealing performance, and having a valve mechanism having excellent durability. And

[0008]

In the electrostatic coating apparatus according to the present invention, a seat valve is provided in a paint supply path for supplying a conductive paint from a paint supply source to a coating gun, and a valve constituting the seat valve is provided. The seat includes a metal sheet body that contacts the seal, a sheet body holder that holds the metal sheet body, and a holder guide that holds the metal sheet body and the sheet body holder. The metal sheet body and the sheet body holder are held movably in the axial direction by the holder guide and with a gap in a direction orthogonal to the axial direction.

Therefore, when the holder guide is screwed into the valve mechanism main body, the metal sheet comes into contact with the seal portion and moves in the radial direction with respect to the holder guide, so that the metal sheet comes in contact with the valve. Be aligned. When the holder guide is further screwed into the valve mechanism main body, the metal sheet body is fixed to the valve mechanism main body.

As described above, the metal sheet body is held in a floating state with respect to the holder guide, and it is possible to position the metal sheet body with respect to the seal portion with high accuracy and reliability. Therefore, the seat valve is excellent in durability, can prevent paint leakage as much as possible, and can be used favorably for a long period of time.

[0011]

FIG. 1 is a schematic structural explanatory view of an electrostatic coating apparatus 20 according to an embodiment of the present invention.

The electrostatic coating apparatus 20 includes a grounded color change valve mechanism (paint supply source) 22 for selectively supplying a plurality of different conductive paints, and a paint gun 24 for spraying the paint.
An intermediate storage tank 26 interposed between the color changing valve mechanism 22 and the coating gun 24; and a paint supply path 28 for supplying a coating material from the color changing valve mechanism 22 to the coating gun 24. There is provided a valve mechanism 30 that is electrically insulated and separated from a first supply path 28a communicating with the color changing valve mechanism 22 and a second supply path 28b to which a high voltage is applied.

The color changing valve mechanism 22 includes air (A), water (W)
Cleaning valve 32 for controlling the supply of cleaning liquid (S) and the like
And a plurality of paint valves 3 capable of supplying different paints
4a to 34c. The valve mechanism 30 includes a movable block 36 connected to the color changing valve mechanism 22 via the first supply path 28a on the non-application side, and the movable block 36 is moved from the air cylinder 38 as shown in FIG. It is connected to an extending rod 40 and is movable back and forth in the direction of arrow A under the guidance of a rail 42.

As shown in FIG. 3 and FIG.
A first connecting portion 46 provided in the first supply path portion 28a having a first on-off valve (seat valve) 44; and a second supply path portion 28b having a second on-off valve (seat valve) 48. And a second connectable to the first connecting portion 46.
And a connection unit 50. The first connecting portion 46 forms a male connecting portion, while the second connecting portion 50 forms a female connecting portion. The first and second pressing end surfaces 52, 54 are provided on the first and second connecting portions 46, respectively, and are respectively supported by the first and second pressing end surfaces 52, 5
The seal member 56, the holder member 58, and the packing member 60 are disposed between the four.

As shown in FIG. 3, the movable block 36 is provided with a first connecting portion 46 in which a first through hole 68 communicating with the first supply path portion 28a is formed. And the first supply path 28 a are opened and closed via a first on-off valve 44. The first on-off valve 44 includes a spring 6
And a needle (valve element) 66 that can move back and forth through the resilient force and air introduced into and out of the air port 64, and paint is guided on an axis in the same direction (arrow A direction) as the operation direction of the needle 66. Valve seat 7 provided with first through hole 68 as an entrance / exit
0.

As shown in FIGS. 5 and 6, the valve seat 70
Is a metal sheet 74 that abuts a sphere (seal portion) 72 provided individually (or integrally) with the needle 66.
And a sheet holder 7 for holding the metal sheet 74
6 and a screw hole 7 formed in the movable block 36 to accommodate the metal sheet 74 and the sheet holder 76.
8 is provided.

One end of the holder guide 80 is formed in a substantially ring shape provided with a disk-shaped side wall 82, and a screw portion 84 to be screwed into the screw hole 78 is formed on the outer peripheral portion. At the center of the holder guide 80, an accommodation portion 86 having a predetermined diameter D1 is provided. This accommodation part 8
6, a first packing 88 is disposed in contact with the side wall 82, and the first packing 88 is attached to the metal sheet body 7.
4 and the sheet body holder 76 are stacked and arranged.

The sheet holder 76 is formed in a substantially ring shape, and has an outer peripheral portion 90 to be inserted into the accommodating portion 86 of the holder guide 80. This outer peripheral portion 90 has a predetermined diameter D
2 and has a relationship of diameter D1> diameter D2. That is, the sheet body holder 76 is movably held in the accommodating portion 86 of the holder guide 80 with a gap S in a direction (arrow B direction) orthogonal to the axial direction. A large diameter portion 92 is formed on one end side of the sheet body holder 76 so as to protrude outward in a radial direction.

The metal sheet 74 is made of, for example, a super-hard material, and has a tapered surface 94 on the center of which the spherical body 72 is seated. A step 96 is formed on the outer peripheral surface of the metal sheet 74, and the step 96 is fitted into a stepped hole 98 of the sheet holder 76. As shown in FIG. 6, the movable block 36 is provided with a stepped hole 100 communicating with the inside of the screw hole 78 and having a smaller diameter than the screw hole 78. The second packing 102 to be disposed is a sheet body holder 76.
Is supported by the large-diameter portion 92.

As shown in FIG. 3, the movable block 36 has first and second dump paths 104 and 106 branched from the first supply path section 28a in the vicinity of the first connection section 46.
Is provided. The first and second dump paths 104,
On the way of 106, first and second dump valves 108 and 110 for opening and closing the first and second dump paths 104 and 106 are provided as close as possible to the first opening and closing valve 44.
The first and second dump valves 108, 110
Needles (valve elements) 120 and 122 that can move forward and backward through the resilience of the two and 114 and the air that is introduced into and led out to the air ports 116 and 118, and a valve seat 124 that can freely seat the needles 120 and 122, 126. The first and second dump valves 108 and 110 have the same configuration as the first on-off valve 44, and a detailed description thereof will be omitted.

The first through hole 68 of the first connection portion 46
The first cleaning path 128 communicates with the first cleaning path 128 via the dump path 106.
A first check valve 130 that allows only the flow of the cleaning liquid from the nozzle 8 to the first through hole 68 is mounted. The first cleaning path 128 communicates with a second cleaning valve 134 via a first switching valve 132, as shown in FIG.

As shown in FIG. 2, a fixed second connection portion 50 is disposed in the casing 144 so as to face the first connection portion 46. As shown in FIG. 4, a second through hole 138 is formed in the second connection portion 50, and the second through hole 138 is connected to the second supply path portion on the application side via the second on-off valve 48. It can communicate with 28b. The second connection part 50 and the second on-off valve 48 are provided in the fixed block 142. The second on-off valve 48 is configured in the same manner as the first on-off valve 44, and the same components are denoted by the same reference numerals, and detailed description thereof will be omitted.

In the vicinity of the second connection part 50, a second cleaning path 148 communicates via a second check valve 146, and the second cleaning path 148 is connected to the second cleaning valve 134 via a second switching valve 150. (See FIG. 1).

As shown in FIG. 2, the intermediate storage tank 26 includes a cylinder 152, in which a piston 154 is disposed so as to be slidable in a reciprocating manner.
A paint filling cylinder chamber 156 is formed by the inner wall portion 2 and the tip of the piston 154. Cylinder 152
The cylinder wall 158 has an injection hole 160 formed at the inner peripheral edge thereof and communicating with the second supply path portion 28b, while communicating with the coating gun 24 at the center thereof. A discharge hole 162 is provided. A plunger 164 is connected to the piston 154, and a nut 166 provided in the plunger 164 has a servomotor 168.
The ball screw 172 connected to the rotating shaft 170 is screwed.

The coating gun 24 includes high voltage applying means 176 connected to a low voltage cable 174, and the low voltage cable 174 is connected to a power source (not shown). A third cleaning valve 180 communicates with the tip side of the coating gun 24 via a third cleaning path 178 (see FIG. 1).

The operation of the electrostatic coating apparatus 20 thus configured will be described below.

First, at the time of electrostatic coating, the movable block 36 is operated under the action of the air cylinder 38 constituting the valve mechanism 30.
Is guided by the rail 42 and moves in the direction of the arrow A1 (see a two-dot chain line in FIG. 2). Thereby, the first connection part 46 is joined to the second connection part 50, and the first and second through holes 68,
138 communicate with each other (see FIG. 6).

When a predetermined color paint is fed from the paint valve 34a of the color changing valve mechanism 22, the paint is supplied to the first supply path under the opening action of the first and second on-off valves 44 and 48. From the section 28a, it is supplied to the second supply path section 28b. For this reason, the paint is filled into the cylinder chamber 156 through the injection hole 160 and further passes through the discharge hole 162 so that the coating gun 2
Fill up to 4.

Next, with the first and second on-off valves 44, 48 closed, a cleaning operation between the first and second connecting portions 46, 50 is performed. That is, as shown in FIG.
The second switching valve 150 is opened, and water and air are sequentially supplied from the second cleaning valve 134 to the second connection portion 50 via the second cleaning path 148. The water and the air introduced into the second connection portion 50 wash the residual paint from the second through hole 138 side of the second connection portion 50, and then enter the second dump path 106 under the opening operation of the second dump valve 110. It is discharged (see arrow X in FIG. 1).

After the above-described cleaning operation is completed, the air cylinder 38
Is driven to separate the first connecting portion 46 from the second connecting portion 50 with an insulating distance (see the solid line in FIG. 2). on the other hand,
In the intermediate storage tank 26, the ball screw 172 is rotated integrally with the rotating shaft 170 under the action of the servomotor 168.
For this reason, the nut member 16 screwed into the ball screw 172
2, the plunger 164 moves integrally with the piston 154 in the direction of arrow A1 in FIG. 2, and the high-voltage applying means 176 is driven. Thereby, the paint to which the high voltage is applied is applied from the painting gun 24 toward the work (not shown).

In this case, in the present embodiment, the paint supply path 2
8, for example, the first on-off valve 4
Even if the opening / closing operation is repeated tens of thousands of times, paint leakage can be reliably prevented, and the first opening / closing valve 44 can be economically obtained with a simple configuration.

That is, as shown in FIGS. 5 and 6,
A metal sheet 74 is provided as a seat on which a sphere 72 serving as a seal portion is seated. A sheet holder 76 holding the metal sheet 74 is provided with a predetermined gap in a radial direction in an accommodation portion 86 of the holder guide 80. S is held. When the holder guide 80 is screwed into the screw hole 78 of the movable block 36, the tapered surface 94 of the metal sheet 74 contacts the outer peripheral surface of the sphere 72. Therefore, the metal sheet 74 moves in the radial direction of the holder guide 80, and the metal sheet 74 is surely aligned with the axis of the sphere 72 and the needle 66.

When the holder guide 80 is further screwed into the screw hole 78, the large-diameter portion 92 of the sheet holder 76 is pressed and supported by the second packing 102, and the other end of the sheet holder 76 and the metal The first packing 8 in which the sheet body 74 is disposed in the holder guide 80
8 to be supported. Accordingly, the valve seat 70 is maintained in a liquid-tight manner.

As a result, in the present embodiment, the first on-off valve 44 having no leakage can be configured with a simple configuration.
Even when the switching operation is performed tens of thousands of times, an effect is obtained that it is possible to reliably prevent the occurrence of paint leakage.

In this embodiment, the structure using the needle 66 as the valve body is adopted, but the present invention can be applied to various seat valve structures such as a ball valve and a poppet valve.

[0036]

In the electrostatic coating apparatus according to the present invention, the metal sheet body which constitutes the valve seat portion and abuts on the seal portion, and the sheet body holder which holds the metal sheet body, have the axis line with respect to the holder guide. The metal sheet body is aligned and fixed by screwing the holder guide to the valve mechanism main body. Therefore, with a simple configuration, the position of the metal sheet body with respect to the seal portion can be adjusted with high accuracy, and a valve mechanism that does not leak paint even with repeated operations and has excellent durability can be obtained. In addition, the manufacturing cost can be effectively reduced.

[Brief description of the drawings]

FIG. 1 is a schematic structural explanatory view of an electrostatic coating apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory longitudinal sectional view of a main part of the electrostatic coating apparatus.

FIG. 3 is an explanatory sectional view of a movable block constituting the electrostatic coating apparatus.

FIG. 4 is an explanatory sectional view of a fixed block constituting the electrostatic coating apparatus.

FIG. 5 is an exploded perspective view of a main part of a valve mechanism constituting the electrostatic coating apparatus.

FIG. 6 is an explanatory longitudinal sectional view of a main part of the valve mechanism.

FIG. 7 is an explanatory longitudinal sectional view of the valve mechanism.

DESCRIPTION OF SYMBOLS 20 ... Electrostatic coating device 22 ... Color changing valve mechanism 24 ... Coating gun 28 ... Paint supply path 28a, 28b ... Supply path section 30 ... Valve mechanism 34a-34c ... Paint valve 36 ... Movable block 44,48 ... open / close valves 46, 50 ... connection part 66 ... needle 70 ... valve seat part 72 ... spherical body 74 ... metal sheet body 76 ... seat body holder 78 ... screw hole 80 ... holder guide 86 ... accommodation part 88, 102 ... packing 90 ... outer periphery Part 92: Large diameter part 94: Tapered surface

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4D075 AA09 AA71 AA74 4F034 AA03 BB04 BB05 4F035 AA03 BA05 BA07 BA12 BA15 BC06 4F042 AB00 CB08 CB18

Claims (1)

[Claims] 1. An electrostatic coating apparatus provided with a valve mechanism for controlling the supply of the conductive paint in a paint supply path for supplying a conductive paint from a paint supply source to a coating gun, wherein the valve mechanism is provided. A seat valve provided with a valve body that moves forward and backward, and a paint outlet provided on an axis in the same direction as the operation direction of the valve body. A metal sheet body abutting on a seal portion provided integrally or individually with the valve body; a sheet body holder holding the metal sheet body; and moving the metal sheet body and the sheet body holder in the axial direction. The metal sheet body is freely aligned and held with a gap in a direction perpendicular to the axial direction, and is screwed to a valve mechanism main body to align the metal sheet body with the valve body. Holder guide to fix body and An electrostatic coating device comprising: