JPH10137636A - Electrostatic coating gun - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic coating gun capable of adjusting the intensity of the electric field between a corona discharge electrode and an article to be coated. SOLUTION: In this electrostatic coating gun wherein an electric filed adjusting earth electrode 5 is provided to the periphery of a gun heat part having corona discharge electrode 1 charging powder paint, the gun heat part is covered with a ground electrode ring 6 having plurality of ground electrodes connected to a ground wire protruding from the outer peripheral surface thereof so as to be freely slidable in a forward and rearward direction and engaging grooves 7 are formed in the outer peripheral surface of the gun head part at a predetermined interval in the forward and rearward direction and the engaging parts hooked with the engaging grooves 7 in a disengageable manner are provided in the inner peripheral surface of the ground electrode ring to make it possible to alter the distance between the ground electrodes and the corona discharge electrode 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic coating gun having a corona discharge electrode for charging a powder coating at a gun tip.

[0002]

2. Description of the Related Art In this type of electrostatic coating gun, the surface of a coating film is easily roughened by corona discharge, and the coating film surface is apt to become an uneven surface which is referred to as yuzu skin.

For this reason, an earth electrode is provided around the corona discharge electrode of the electrostatic coating gun, and the intensity of the electric field between the corona discharge electrode and the object to be coated is adjusted to obtain a smooth coating surface. I am trying to be.

[0004]

However, as described above, the strength of the electric field between the corona discharge electrode of the electrostatic coating gun and the object to be coated is determined to be large enough that the earth electrode does not form a slick skin on the coating film surface. Even when adjusted, the electric field tends to concentrate on the edge of the object to be coated, so that the coating thickness at the edge of the object to be coated is thicker than other parts, Easy to be formed.

[0005] When the thickness of the coating on the edge of the object to be coated is increased, when the edge of the object to be coated is inserted into a slit or a recess having a predetermined width and assembled, the insertion is hindered. A problem arises.

Accordingly, the present invention provides an electrostatic coating gun capable of adjusting the intensity of an electric field between a corona discharge electrode and an object so that the electric field of the corona discharge does not concentrate on the edge of the object. It is intended to provide.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention has a static electrode in which a ground electrode for electric field adjustment is provided around a gun tip having a corona discharge electrode for charging a powder coating material. In the electropaint gun, a plurality of ground electrodes connected to a ground wire projecting on the outer peripheral surface of the gun tip portion are slidably covered in the front-rear direction,
An engaging groove is formed on the outer peripheral surface of the gun tip at predetermined intervals in the front-rear direction, and an engaging portion that is hooked to the engaging groove so as to be removably engaged is provided on the inner peripheral surface of the ground electrode ring. It is.

By adopting the above configuration, the ground electrode ring is slid in the front-rear direction to form engagement grooves formed at predetermined intervals in the front-rear direction on the outer peripheral surface of the gun tip, and the inner peripheral surface of the ground electrode ring. When the engagement position with the engagement part is changed,
The distance between the ground electrode and the corona discharge electrode also changes.

Therefore, when the object to be coated is passed by the transfer device in a face-to-face state with the electrostatic coating gun to perform the coating,
By changing the distance between the ground electrode and the corona discharge electrode, the electric field between the corona discharge electrode and the object can be adjusted, so that the electric field concentrates on the edge of the object and The formation can be reduced.

[0010]

1 to 5 show an embodiment of an electrostatic coating gun according to the present invention.

This electrostatic coating gun has, at the tip of the gun, a cap 3 on which a muzzle 2 provided with a corona discharge electrode 1 is mounted.

The corona discharge electrode 1 is connected to a high voltage generator and charges the powder coating material discharged from the muzzle 2 by corona discharge.

A plurality of earth electrodes 5 connected to an earth wire 4 are slidably covered in the front-rear direction on the cap 3.

Engagement grooves 7 are formed on the outer peripheral surface of the cap 3 at predetermined intervals of about 5 mm in the front-rear direction. The engagement grooves 7 are formed in three rows in the circumferential direction of the cap 3.

The earth electrode ring 6 includes a front ring 8 and a rear ring 9 made of synthetic resin, and a metal ring 10 sandwiched between the front ring 8 and the rear ring 9.

The front ring 8 and the rear ring 9 are integrated by screws 11 with the metal ring 10 interposed therebetween, and the metal ring 10 is connected to the ground wire 4. .

On the front surface of the rear ring 9, the metal ring 10 and a projecting wall portion 12 formed on the rear surface of the front ring 8.
Is formed, and a part of the outer peripheral surface of the protruding wall portion 12 is exposed from the groove portion 13 in a state where the metal ring 10 and the protruding wall portion 12 of the front ring 8 are fitted into the groove portion 13. ing.

On the protruding wall portion 12 of the front ring 8 exposed from the groove portion 13, a metal wire such as tungsten forming the six earth electrodes 5 is provided so as to penetrate from the outer peripheral surface toward the inner peripheral surface. ing. The six metal wires protruding toward the inner circumference of the front ring 8 are bent toward adjacent metal wires, and the six metal wires form one side of a hexagon contacting the inner circumference of the front ring 8. The hexagonal metal wire portion forms an engaging portion 14 that is detachably engaged with the engaging groove 7 on the outer peripheral surface of the cap 3.

A metal tape 15 for electrically connecting the metal wires is attached to the front ring 8 at each apex position of the hexagon where the metal wires are in contact.

Each metal wire is electrically connected by a metal ring 10 via a metal tape 15.

Since the engaging portion 14 is formed by a hexagonal metal wire as described above, the hexagonal metal wire has a hexagonal shape with respect to the three rows of engaging grooves 7 formed on the outer peripheral surface of the cap 3. It is designed to engage on three sides. The front and rear surfaces of each of the engagement grooves 7 are formed as inclined surfaces inclined toward the bottom of the engagement groove 7, as shown in FIG. Therefore, in the state where the metal wires of the three sides of the hexagon forming the engaging portion 14 are fitted in the three rows of the engaging grooves 7, the ground electrode ring 6
When a strong force is applied in the front-rear direction, the metal wire is deformed by its elasticity and gets over the inclined planes before and after the engagement groove 7, so that the earth electrode ring 6 can be moved back and forth. If the earth electrode ring 6 is slightly rotated in the circumferential direction from the state of FIG. 3 so that none of the six sides of the hexagonal metal wire fits into the engagement groove 7, the six side metal wires can be obtained. However, since the ground electrode ring 6 is not caught in the engaging groove 7, the earth electrode ring 6 can be easily moved back and forth.

[0022]

As described above, the electrostatic coating gun according to the present invention moves the earth electrode ring back and forth in accordance with the shape of the powder paint or the object to be coated, so that the corona discharge electrode and the object to be coated can be separated. It is possible to adjust the strength of the electric field during
This has the effect of obtaining a smooth coating film surface with a constant thickness and no scum.

[Brief description of the drawings]

FIG. 1 is an overall view showing an example of an electrostatic coating gun according to the present invention.

FIG. 2 is an exploded perspective view of a gun tip portion of the electrostatic coating gun according to the present invention in a state where an earth electrode ring is disassembled.

FIG. 3 is a sectional view taken along line AA of FIG. 1;

FIG. 4 is a sectional view taken along line BB of FIG. 3;

FIG. 5 is a sectional view taken along line CC of FIG. 3;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 corona discharge electrode 2 muzzle 3 cap 4 ground wire 5 ground electrode 6 ground electrode ring 7 engaging groove 8 front ring 9 rear ring 10 metal ring 11 screw 12 protruding wall portion 13 groove portion 14 engaging portion 15 metal tape

Claims (2)

[Claims] 1. An electrostatic coating gun having an earth electrode for electric field adjustment around a gun tip having a corona discharge electrode for charging a powder coating, wherein the gun tip is connected to an earth wire. A plurality of earth electrodes projecting from the outer peripheral surface are slidably covered in the front-rear direction with an earth electrode ring, and engagement grooves are formed on the outer peripheral surface of the gun tip at predetermined intervals in the front-rear direction. An electrostatic coating gun characterized in that a detachable engaging portion is provided on an inner peripheral surface of a ground electrode ring. 2. The method according to claim 1, wherein the engaging portion is formed by a metal wire stretched in a polygon around the inner periphery of the ground electrode ring.
2. The electrostatic coating gun according to claim 1, wherein the metal wire is formed integrally with a ground electrode protruding from the outer peripheral surface of the ground electrode ring.