JP2008168233A - Electrostatic coating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To more reduce the amount of unused conductive coating left in a coating supply passage. <P>SOLUTION: An intermediate storage tank 14 is equipped with a cylinder 40, a first piston 51, a second piston 52, the piston rod 58 attached to the second piston 52, a drive part 61 for driving the piston rod 58 and a valve mechanism 63 for allowing the water 66 in the upper chamber 53 provided on the side of the second piston 52 of the first piston 51 to flow in the lower chamber 54 provided on the end part side of the cylinder 40 of the first piston 51 at the point of time when the conductive coating 65 in the lower chamber 54 becomes a predetermined volume when the conductive coating 65 is supplied to a coating gun from the lower chamber 54 by moving the first piston 51 through the second piston 52 and water 66 by the drive part 61 in a state that the lower chamber 54 is filled with the conductive coating 65 and the upper chamber 53 is filled with the water 66. The conductive coating 65 is extruded to the coating gun by the water 66 supplied from the inside of the lower chamber 54. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an improvement of an electrostatic coating apparatus.

As a conventional electrostatic coating device, a reservoir for temporarily storing conductive paint is provided in the paint supply path for supplying conductive paint from the paint supply section to the coating gun, and the paint supply path is washed when the color of the conductive paint is changed. Is known (for example, see Patent Document 1).
JP 2004-275976 A

FIG. 1 of Patent Document 1 will be described with reference to FIG. In addition, the code | symbol was reassigned.
FIG. 7 is an explanatory view of a conventional electrostatic coating apparatus.
The electrostatic coating apparatus 100 includes a first cleaning valve 101 that controls the supply of drying air A, water W, and cleaning liquid S, and is connected to a supply unit (not shown) that supplies a plurality of conductive paints having different colors. A color change valve mechanism 105 composed of paint valves 102, 103, 104 for controlling the supply of these conductive paints, and this color change valve mechanism 105 is electrically connected to the coating gun side, which will be described in detail later. It comprises a block valve mechanism 106 that insulates, an intermediate storage tank 107 that is connected to the block valve mechanism 106 and temporarily stores conductive paint, and a coating gun 108 connected to the intermediate storage section 107.

  The block valve mechanism 106 includes a switching valve 112 connected to the color change valve mechanism 105 via a supply path 111, and a switching valve 112 connected to the switching valve 112 via a supply path 113 as a resin-made electrically insulating conduit. And valve 114. Reference numeral 116 denotes a first drainage channel connected to the supply channel 111 via a first dump valve 117, and 118 denotes a second cleaning valve which is connected to the switching valve 112 and controls the supply of air A, water W and cleaning liquid S. , 121 is a second discharge path connected to the switching valve 114 via a one-way valve 119.

The switching valve 112 switches between the color change valve mechanism 105 side and the second cleaning valve 118 side.
The switching valve 114 switches between the intermediate storage tank 107 side connected via the supply path 123 and the second drainage path 121 side.

  The intermediate storage tank 107 includes a cylinder 125, a piston 126 movably inserted into the cylinder 125, a rod 127 attached to the piston 126, a cylinder chamber 128 formed by the cylinder 125 and the piston 126, The injection port 131 and the discharge port 132 are provided at the end of the cylinder 125 and communicate with the cylinder chamber 128.

  The rod 127 is connected to the servo motor 134 via the ball screw means 135, and the servo motor 134 is driven so that the rod 127 and the piston 126 are moved in the cylinder axial direction (direction A in the figure) via the ball screw means 135. Move forward and backward.

  The coating gun 108 is connected to the discharge port 132 of the intermediate storage tank 107 via a delivery path 137, and includes a second dump valve 141 and a trigger valve 142 connected to the delivery path 137, and applies a high voltage application (not shown). Connected to the means. In addition, 108a is a jet nozzle of the coating gun 108, and is a part which comprises the edge part of the delivery path 137. FIG.

The second dump valve 141 is connected to a third discharge path 144 for discharging waste liquid containing conductive paint and cleaning liquid generated during cleaning to the outside of the delivery path 137.
The third discharge path 144 is connected via a one-way valve 147 to a third cleaning valve 146 that controls the supply of air A, water W and cleaning liquid S.

The trigger valve 142 controls ejection of the conductive paint from the painting gun 108.
The supply paths 111, 113, and 123, the intermediate storage tank 107, and the delivery path 137 described above constitute a paint supply path 148 that extends from the paint supply unit to the coating gun 108.

Next, the operation of the electrostatic coating apparatus 100 described above will be described.
In order to perform electrostatic coating, first, the switching valves 112 and 114 of the block valve mechanism 106 are opened and the supply passages 111, 113, and 123 are connected. For example, the paint valve 102 of the color changing valve mechanism 105 is opened, and intermediate storage is performed. The servo motor 134 of the tank 107 is driven to move the piston 126 in the A1 direction.

  As a result, the conductive paint of a predetermined color passes from the paint valve 102 through the supply paths 111, 113, and 123 to the cylinder chamber 128 of the intermediate storage tank 107 and is filled therewith. At this time, the second dump valve 141 and the trigger valve 142 are closed.

  Next, the switching valve 114 is closed, the trigger valve 142 is opened, and the servo motor 134 is driven to move the piston 126 in the A2 direction, whereby the conductive paint is pumped from the cylinder chamber 128 to the delivery path 137, and the trigger valve The conductive paint is ejected from the coating gun 108 through 142 and a high voltage is applied to the conductive paint, whereby electrostatic painting is performed on an object to be coated (not shown).

  When electrostatic coating is performed with a conductive paint of a different color after the electrostatic coating described above, the supply paths 111, 113, 123 are connected, the second dump valve 141 and the trigger valve 142 are opened, and the first 1 The cleaning valve 101 is opened to allow the cleaning liquid to flow into the supply paths 111, 113, 123, the intermediate storage tank 107, the delivery path 137, and the third discharge path 144 and to be ejected from the coating gun 108 to clean the coating supply path.

  At this time, it is possible to partially clean the paint supply path, but unused conductive paint remaining in the paint supply path is discarded, which is uneconomical. It is desirable to reduce the amount of conductive paint remaining in the paint supply path.

  An object of the present invention is to reduce the amount of unused conductive paint remaining in a paint supply path from an economical viewpoint in an electrostatic coating apparatus.

  The invention according to claim 1 is an electrostatic coating apparatus in which a reservoir for temporarily storing conductive paint is provided in a paint supply path for supplying conductive paint from a paint supply to a coating gun. A first piston and a second piston movably inserted into the cylinder, a piston rod attached to the second piston, a drive unit for driving the piston rod, and a cylinder end of the first piston In the state where the first chamber provided on the side is filled with conductive paint and the second chamber provided on the second piston side of the first piston is filled with water, the first piston passes through the second piston and water in the drive unit. A valve mechanism that causes water in the second chamber to flow into the first chamber when the conductive coating in the first chamber reaches a predetermined capacity when the conductive coating is supplied from the first chamber to the coating gun. Water provided from the first chamber Wherein the extruding the conductive paint.

As an effect, electrostatic coating is performed by filling the first chamber with conductive paint and filling the second chamber with water, and driving the piston chamber, the second piston, and water through the piston rod, the second piston, and water. Pressure is applied to the conductive paint, and the conductive paint is supplied from the first chamber to the coating gun.
When the remaining amount of the conductive paint in the first chamber reaches a predetermined capacity, the water in the second chamber whose pressure is increased by opening the valve mechanism is caused to flow into the first chamber, and the water in the first chamber becomes conductive. The paint is pushed out to the paint gun side, and conductive paint is ejected from the paint gun.

  At the end of painting, the paint supply path from the first chamber to the spray gun outlet can be almost filled with water, so the conductive paint is replaced by water and the amount remaining in the paint supply path is reduced. The amount of electrostatic paint discarded during cleaning is reduced.

  In the invention according to claim 1, the storage portion includes a cylinder, a first piston and a second piston movably inserted in the cylinder, a piston rod attached to the second piston, and the piston rod. A drive unit for driving, and a drive unit in a state in which the first chamber provided on the cylinder end side of the first piston is filled with conductive paint and the second chamber provided on the second piston side of the first piston is filled with water. When the first piston is moved through the second piston and water and the conductive paint is supplied from the first chamber to the coating gun, the second chamber is reached when the conductive paint in the first chamber reaches a predetermined capacity. A valve mechanism for flowing the water in the room into the first room, and pushes out the conductive paint with the water supplied from the first room, so when washing the paint supply path to change the color of the conductive paint, Reduce conductive paint to be discarded Bets can be, also, to be able to shorten the cleaning time, it is possible to improve the economy.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.
FIG. 1 is an explanatory view of an electrostatic coating apparatus according to the present invention. An electrostatic coating apparatus 10 includes a paint supply unit 11 serving as a supply source of conductive paints of a plurality of colors, and a supply path to the paint supply unit 11. 12 and the intermediate storage tank 14 connected via the switching valve 13, the coating gun 18 connected to the intermediate storage tank 14 via the switching valve 13 and the supply path 17, and water to the intermediate storage tank 14. In order to supply air to the intermediate storage tank 14, the water supply section 21 connected via the supply path 19 and the air supply section 24 connected via the switching valve 22 and the supply path 23, and the intermediate storage tank A waste liquid tank 27 connected to the switching valve 13 via a flow path 26 for storing waste liquid when the inside is cleaned with air, and an intermediate storage tank 14 for discharging the cleaning waste liquid from the intermediate storage tank 14 Switching valve 31 and channel provided between channel 26 2 and a cleaning liquid supply unit 34 connected to the end of the supply path 12 via a supply path 33 in order to clean the supply path 12 with the cleaning liquid, and a high voltage is applied to the conductive paint during electrostatic coating. And a block valve mechanism (not shown) for electrically blocking the paint gun 18 side and the paint supply unit 11, the water supply unit 21, the air supply unit 24, and the cleaning liquid supply unit 34 side.
The supply path 12, the switching valve 13, the intermediate storage tank 14, and the supply path 17 form a paint supply path 36 that supplies conductive paint from the paint supply unit 11 to the paint gun 18.

  FIG. 2 is a cross-sectional view of the intermediate storage tank according to the present invention. The intermediate storage tank 14 includes a cylinder 40 and pipes 41 to 41 attached to the lower ends of the cylinder 40 and connected to the switching valves 22, 13, and 31. 43, a pin 44 attached to the bottom of the cylinder 40, a first piston 51 and a second piston 52 movably inserted into the cylinder 40, and an upper chamber 53 formed above the first piston 51. A first water supply valve 56 provided in the first piston 51 for supplying water to a lower chamber 54 formed below the first piston 51 and a second piston 52 for supplying water to the upper chamber 53. A second water supply valve 57 provided on the piston 40, a piston rod 58 attached to the second piston 52, and a drive unit 61 attached to the upper end of the cylinder 40 for driving the piston rod 58.

  The first water supply valve 56 described above constitutes a valve mechanism 63 with the pin 44, and a valve seat 56 b attached so as to close the opening of the hole 51 a formed in the lower surface of the first piston 51, A ball 56d as a valve body housed in the hole 51a to block the water passage 56c opened in the seat 56b, and an upper end of the hole 51a and the ball to press the ball 56d against the edge of the water passage 56c And a compression coil spring 56e disposed between them. Reference numeral 51b denotes a water passage that penetrates from the upper end of the hole 51a to the upper surface of the first piston 51.

  As an action of the valve mechanism 63, in a state where the lower chamber 54 is filled with conductive paint and the upper chamber 53 is filled with water, the drive unit 61 is operated to lower the second piston 52 via the piston rod 58, Furthermore, when the first piston 51 is lowered through water and the conductive paint is supplied from the lower chamber 54 to the coating gun 18 (see FIG. 1), the conductive paint in the lower chamber 54 has a predetermined capacity. At that time, the first water supply valve 56 is opened by the pin 44 and the water in the upper chamber 53 flows into the lower chamber 54.

The operation of the electrostatic coating apparatus 10 described above will be described with reference to FIGS.
FIGS. 3A to 3C are first operation diagrams showing the operation of the electrostatic coating apparatus according to the present invention.
In (a), the conductive paint 65 supplied from the paint supply unit 11 (see FIG. 1) is filled into the lower chamber 54, and the water 66 supplied from the water supply unit 21 (see FIG. 1) is filled into the upper chamber 53. From this state, the switching valve 13 is switched to connect the supply path 17 to the lower chamber 54, the drive unit 61 is operated, and the piston rod 58 is extended downward, whereby the second piston 52, the water 66, and the first piston 51 are connected. The conductive paint 65 is supplied to the coating gun 18 (see FIG. 1) via the supply path 17 and is ejected from the coating gun 18 (see FIG. 1) onto the object to be coated.

(B) shows a state in which the first piston 51 is moved down most in the cylinder 40 together with the water 66 and the second piston 52. At this time, there is a gap 68 between the bottom of the cylinder 40 and the first piston 51, and the conductive paint 65 remains slightly in this gap 68.
At this time, the ball 56d of the first water supply valve 56 hits the pin 44 to open the first water supply valve 56, and the upper chamber 53 and the lower chamber 54 are in communication.

  In (c), when the second piston 52 is further lowered through the piston rod 58 by the drive unit 61, the water 66 in the upper chamber 53 flows into the supply passage 17 through the lower chamber 54, and the supply passage 17. Extrude the conductive paint inside. As a result, the conductive paint in the supply path 17 reaches the coating gun 18 (see FIG. 1) and is ejected.

4 (a) and 4 (b) are second operation diagrams showing the operation of the electrostatic coating apparatus according to the present invention.
(A) shows a state in which the water 66 begins to push out the conductive paint 55 in the supply path 17. A conductive paint 65 is ejected from the ejection port 18 a of the coating gun 18.

  (B) has shown the state which completed electrostatic coating. Since the water 66 almost pushed out the conductive paint 65 in the supply passage 17, the conductive paint 65 remains slightly in the vicinity of the jet nozzle 18a. Thus, when the conductive coating 65 slightly remains in the vicinity of the jet nozzle 18a, the electrostatic coating is terminated, so that the amount of the conductive coating 65 to be discarded when cleaning the supply path 17 is reduced. The water 66 does not spout from the spout 18a.

FIGS. 5A and 5B are third operation diagrams showing the operation of the electrostatic coating apparatus according to the present invention.
(A) is a state where the second piston 52 is lowered until it hits the first piston 51, where the extrusion of the conductive paint 65 with the water 66 is finished, and the electrostatic coating is finished.

  When a conductive paint having a color different from that of the conductive paint described above is used next, the switching valve 22 is opened and supplied from the air supply unit 24 (see FIG. 1) in order to clean the gap 68 in the lower chamber 54. Air is supplied to the gap 68 through the path 23. The waste liquid after cleaning the gap 68 flows to the flow path 26 via the switching valve 13, flows to the flow path 32 via the switching valve 31, and accumulates in the waste liquid tank 27 (see FIG. 1).

(B) shows a state in which the gap 68 is cleaned by supplying air to the gap 68 in the lower chamber 54. After cleaning the lower chamber 54, in FIG. 1, the cleaning liquid is supplied from the cleaning liquid supply unit 34 through the supply path 33 into the supply path 12 for cleaning, and the cleaned waste liquid is supplied to the waste liquid tank 27. 5B, the switching valve 13 is switched to connect the supply passage 12 and the lower chamber 54.
And the 2nd water supply valve 57 is opened, the drive part 61 is operated, and the 2nd piston 52 is raised.

6 (a) and 6 (b) are fourth operation diagrams showing the operation of the electrostatic coating apparatus according to the present invention.
In (a), if the 2nd piston 52 is raised, the 1st piston 51 will also raise with this, and conductive paint will be sent from paint supply part 11 (refer to Drawing 1) to lower chamber 54 with the pressure fall of lower chamber 54. 65 is supplied.

In (b), after filling the negligible 54 with a predetermined capacity of the conductive paint 65, the second water supply valve 57 is opened to further raise the second piston 52, and the supply path from the water supply unit 21 (see FIG. 1). Water 66 is supplied to the upper chamber 53 through 19.
And in order to perform electrostatic coating, the process of the above FIGS. 3-6 is implemented.

  As shown in FIGS. 1, 3, and 4, as a storage unit that temporarily stores the conductive paint 65 in the paint supply path 36 that supplies the conductive paint 65 from the paint supply unit 11 to the coating gun 18. In the electrostatic coating apparatus 10 provided with the intermediate storage tank 14, the cylinder 40, the first piston 51 and the second piston 52 that are movably inserted into the cylinder 40, and the second A piston rod 58 attached to the piston 52, a drive unit 61 for driving the piston rod 58, and a conductive paint 65 in a lower chamber 54 as a first chamber provided on the cylinder end side of the first piston 51, The first piston 51 is passed through the second piston 52 and the water 66 by the drive unit 61 in a state where the upper chamber 53 as the second chamber provided on the second piston 52 side of the first piston 51 is filled with the water 66. When the conductive paint 65 in the lower chamber 54 reaches a predetermined capacity when the conductive paint 65 is supplied from the lower chamber 54 to the coating gun 18, the water 66 in the upper chamber 53 is drained into the lower chamber 54. And a valve mechanism 63 that flows into the lower chamber 54, and the conductive paint 65 is pushed out toward the coating gun 18 with water 66 supplied from the lower chamber 54.

  Thereby, when the coating material supply path 36 is cleaned in order to change the color of the conductive coating material 65, the conductive coating material 65 to be discarded can be reduced, and the cleaning time can be shortened. Economic efficiency can be improved.

  In this embodiment, as shown in FIGS. 3A to 3C, the upper chamber 53 is filled with the water 66, but not limited to this, the upper chamber 53 is filled with the cleaning liquid. Also good. Thereby, when extruding the conductive paint with the cleaning liquid, the paint supply path can be cleaned, and the cleaning time can be shortened.

  The electrostatic coating apparatus of the present invention is suitable for electrostatic coating of automobiles.

It is explanatory drawing of the electrostatic coating apparatus which concerns on this invention. It is sectional drawing of the intermediate | middle storage tank which concerns on this invention. It is a 1st operation | movement figure which shows the effect | action of the electrostatic coating apparatus which concerns on this invention. It is a 2nd operation | movement figure which shows an effect | action of the electrostatic coating apparatus which concerns on this invention. It is a 3rd operation | movement figure which shows the effect | action of the electrostatic coating apparatus which concerns on this invention. It is a 4th operation | movement figure which shows the effect | action of the electrostatic coating apparatus which concerns on this invention. It is explanatory drawing of the conventional electrostatic coating apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Electrostatic coating apparatus, 11 ... Paint supply part, 14 ... Storage part (intermediate storage tank), 18 ... Paint gun, 36 ... Paint supply path, 40 ... Cylinder, 51 ... 1st piston, 52 ... 2nd piston, 53 ... 2nd chamber (upper chamber), 54 ... 1st chamber (lower chamber), 58 ... Piston rod, 61 ... Drive part, 63 ... Valve mechanism, 65 ... Conductive paint, 66 ... Water.

Claims (1)

In the electrostatic coating apparatus provided with a storage unit for temporarily storing the conductive paint in a paint supply path for supplying the conductive paint from the paint supply unit to the coating gun,
The storage section includes a cylinder, a first piston and a second piston movably inserted into the cylinder, a piston rod attached to the second piston, a driving section for driving the piston rod, In the state where the first chamber provided on the cylinder end side of one piston is filled with conductive paint and the second chamber provided on the second piston side of the first piston is filled with water, When the conductive paint in the first chamber reaches a predetermined capacity when the first piston is moved through the first chamber and the conductive paint is supplied from the first chamber to the coating gun, the water in the second chamber is drained from the first chamber. And a valve mechanism for flowing through
An electrostatic coating apparatus for extruding conductive paint with water supplied from a first chamber.

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