JP3768306B2 - Electrostatic painting gun - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrostatic coating gun having a corona discharge electrode for charging a powder coating at the tip of the gun.
[0002]
[Prior art]
In this type of electrostatic coating gun, the coating surface is roughened due to corona discharge, and it tends to be a non-smooth coating surface called “skin skin”.
[0003]
For this reason, a ground electrode is installed around the corona discharge electrode of the electrostatic coating gun, and the strength of the electric field between the corona discharge electrode and the object to be coated is adjusted to obtain a smooth coating surface. ing.
[0004]
[Problems to be solved by the invention]
However, even if the strength of the electric field between the corona discharge electrode of the electrostatic coating gun and the object to be coated is adjusted to such a level that the ground electrode does not form a crushed skin on the surface of the coating, Since the electric field tends to concentrate on the edge of the object, the coating film thickness of the edge of the object to be coated is thicker than other parts, and the skin is likely to be formed on the edge.
[0005]
And, when the coating film thickness of the edge of the object to be coated becomes thick, there is a problem in that the insertion of the edge of the object to be coated is hindered when it is assembled into a slit or a recess formed to a predetermined width. Occurs.
[0006]
Accordingly, the present invention provides an electrostatic coating gun capable of adjusting the strength of the electric field between the corona discharge electrode and the object to be coated so that the electric field of the corona discharge does not concentrate on the edge of the object to be coated. It is what.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides an electrostatic coating gun in which a ground electrode for electric field adjustment is provided around a gun tip having a corona discharge electrode for charging a powder paint. A ground electrode ring with a plurality of ground electrodes connected to the ground wire projecting on the outer peripheral surface is slidable in the front-rear direction, and engagement grooves are formed at predetermined intervals in the front-rear direction on the outer peripheral surface of the gun tip. And the structure which provided the engaging part hooked in this engagement groove so that engagement / disengagement was provided in the internal peripheral surface of the earth electrode ring was employ | adopted.
[0008]
By adopting the above configuration, the ground electrode ring is slid in the front-rear direction, and the engagement groove formed on the outer peripheral surface of the gun tip at a predetermined interval in the front-rear direction and the inner peripheral surface of the ground electrode ring are engaged. When the engagement position with the part is changed, the distance between the ground electrode and the corona discharge electrode also changes.
[0009]
Therefore, when coating the object to be coated by passing it through the electrostatic coating gun in a face-to-face state, the distance between the corona discharge electrode and the object to be coated is changed by changing the distance between the ground electrode and the corona discharge electrode. Since the electric field can be adjusted, it is possible to reduce the concentration of the electric field on the edge of the object to be coated and the formation of the yuzu skin.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
1 to 5 show an embodiment of an electrostatic coating gun according to the present invention.
[0011]
This electrostatic coating gun has a cap 3 on which a muzzle 2 provided with a corona discharge electrode 1 is mounted at the tip of the gun.
[0012]
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.
[0013]
The cap 3 is covered with a ground electrode ring 6 from which a plurality of ground electrodes 5 connected to the ground wire 4 protrude on the outer peripheral surface so as to be slidable in the front-rear direction.
[0014]
Engaging grooves 7 are formed on the outer peripheral surface of the cap 3 in the front-rear direction at a predetermined interval of about 5 mm. The engagement grooves 7 are formed in three rows in the circumferential direction of the cap 3.
[0015]
The ground 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.
[0016]
The front ring 8 and the rear ring 9 are integrated with a screw 11 with a metal ring 10 sandwiched therebetween, and a ground wire 4 is connected to the metal ring 10.
[0017]
The front surface of the rear ring 9 is formed with a groove portion 13 into which the metal ring 10 and a protruding wall portion 12 formed on the rear surface of the front ring 8 are fitted. The protruding wall of the metal ring 10 and the front ring 8 is formed in the groove portion 13. A part of the outer peripheral surface of the projecting wall portion 12 is exposed from the groove portion 13 in a state where the portion 12 is fitted.
[0018]
The protruding wall portion 12 of the front ring 8 exposed from the groove portion 13 is provided so that metal wires such as tungsten forming the six ground electrodes 5 penetrate from the outer peripheral surface toward the inner peripheral surface. The six metal wires projecting to the inner periphery of the front ring 8 are bent toward the adjacent metal wires, and each of the six metal wires forms one side of a hexagon in contact with the inner periphery of the front ring 8. The hexagonal metal wire portion constitutes an engaging portion 14 that is detachably hooked into the engaging groove 7 on the outer peripheral surface of the cap 3.
[0019]
A metal tape 15 for electrically connecting each metal wire is attached to the front ring 8 at each vertex position of the hexagon where each metal wire contacts.
[0020]
Each metal wire is electrically connected by a metal ring 10 through a metal tape 15.
[0021]
Since the engaging portion 14 is formed of a hexagonal metal wire as described above, the hexagonal three sides of the three rows of engaging grooves 7 formed on the outer peripheral surface of the cap 3 are used. It is designed to engage. The front and rear surfaces of each engagement groove 7 are formed as inclined surfaces that are inclined toward the bottom of the engagement groove 7 as shown in FIG. Therefore, when a force is applied to the ground electrode ring 6 in the front-rear direction with the hexagonal three-side metal wires constituting the engaging portion 14 fitted in the three rows of engaging grooves 7, the metal wires are Since it is deformed by the elasticity and gets over the front and rear inclined surfaces of the engagement groove 7, the ground electrode ring 6 can be moved back and forth. Further, if the earth electrode ring 6 is slightly rotated in the circumferential direction from the state of FIG. 3 so that none of the hexagonal six-sided metal wires fit into the engaging grooves 7, the six-sided metal wires However, since the engagement groove 7 is not caught, the ground electrode ring 6 can be easily moved back and forth.
[0022]
【The invention's effect】
As described above, the electrostatic coating gun according to the present invention moves the ground electrode ring back and forth according to the shape of the powder coating or the object to be coated, thereby generating an electric field between the corona discharge electrode and the object to be coated. Since the strength can be adjusted, there is an effect that a smooth coating film surface having a constant film thickness and no undue skin can be obtained.
[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 a perspective view of a gun tip portion of the electrostatic coating gun according to the present invention with an earth electrode ring disassembled. FIG. 4 is a sectional view taken along line BB in FIG. 3. FIG. 5 is a sectional view taken along line CC in FIG.
DESCRIPTION OF SYMBOLS 1 Corona discharge electrode 2 Muzzle 3 Cap 4 Ground wire 5 Ground electrode 6 Ground electrode ring 7 Engagement groove 8 Front ring 9 Back ring 10 Metal ring 11 Screw 12 Projection wall part 13 Groove part 14 Engagement part 15 Metal tape

Claims (1)

In an electrostatic coating gun in which a ground electrode for electric field adjustment is provided around a tip of a gun having a corona discharge electrode for charging a powder paint, a plurality of ground electrodes connected to a ground wire are provided at the tip of the gun. A ground electrode ring projecting on the outer peripheral surface is slidable in the front-rear direction, and an engagement groove is formed in the front-rear direction on the outer peripheral surface of the gun tip portion at a predetermined interval, and the engagement groove is detachably hooked. The joint portion is provided on the inner peripheral surface of the ground electrode ring, and the engaging portion is formed by a metal wire stretched in a polygonal shape on the inner periphery of the ground electrode ring, and the metal wire is formed on the outer peripheral surface of the ground electrode ring. An electrostatic coating gun characterized in that it is formed integrally with a ground electrode projecting on the surface .

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