JP2003019450A - Electrostatic coating gun - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the fluctuation of voltage produced in a high voltage producing apparatus which is caused by the high voltage producing apparatus placed close to a gun main body composed of a conductive material. SOLUTION: A shield plate (shield layer) arranged to correspond to a transformer 21 and grounded is provided on the outside surface of a housing 22 of the high voltage producing apparatus 20. The positioning relation between the transformer 21 housing in the housing 22 and the grounded shield plate 24 provided on the outside surface of the housing 22 is always fixed. Then, the high voltage producing apparatus 20 produces fixed high voltage regardless of whether the high voltage producing apparatus 20 is arranged close to the gun main body 10 or not.

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.

[0002]

2. Description of the Related Art In an electrostatic coating gun, a high voltage generator is installed inside the gun body, a high voltage is applied to the paint supplied to the gun body, and the paint is discharged and applied to a grounded object. It is designed to be worn. There are several types of guns with different shapes and dimensions depending on the purpose of use, etc.There are also multiple types of high voltage generators with different shapes and dimensions depending on the value of the voltage applied to the paint. Has been done,
They are used in an appropriate combination according to the coating conditions.

[0003]

The gun body of the electrostatic coating gun uses a conductive material such as metal or conductive synthetic resin in order to release the static electricity charged on the body of the worker to the ground. Therefore, when the high voltage generator is installed in a position close to the gun body, the magnetic field lines of the transformer in the high voltage generator are affected by the conductive gun body,
The high voltage generator sometimes had a voltage value different from the voltage value originally supposed to be generated. Also, when comparing electrostatic coating guns with the same combination of high voltage generator and gun body, if the gun body is made of conductive synthetic resin material, the distribution of conductors in the resin Since the method also subtly affects the magnetic field lines of the transformer,
There is a possibility that the voltage value generated between the electrostatic coating guns may vary.

The present invention was devised in view of the above circumstances, and the voltage generation value in the high voltage generator fluctuates due to the fact that the high voltage generator is arranged close to the gun body made of a conductive material. The purpose is to prevent.

[0005]

According to a first aspect of the present invention, a high voltage generator having a transformer housed in a housing is housed inside a gun body made of a conductive material. In an electrostatic coating gun in which a high voltage is applied to the supplied paint and the paint is discharged from the gun body and applied to a grounded object, the outer surface of the housing corresponds to the transformer. And a shield layer in a state of being grounded.

According to a second aspect of the present invention, in the electrostatic painting gun according to the first aspect of the invention, the housing is configured to enclose the transformer with a resin mold.
The housing includes a primary mold part made of an elastic synthetic resin material for covering the transformer, and a secondary mold part made of a solvent resistant synthetic resin material for covering an outer surface of the primary mold part and forming a surface of the housing. And a section.

[0007]

[Invention 1] The positional relationship between the transformer housed in the housing and the shield layer provided on the outer surface of the housing and grounded is as follows.
It is always constant. Therefore, regardless of whether the high voltage generator is placed close to the gun body,
Generates a high voltage of constant value. [Invention of Claim 2] Since the secondary mold part constituting the surface of the housing has solvent resistance, the primary mold part and the transformer are not attacked by the solvent at the time of cleaning. In addition, impact due to dropping during use, heat shock during cleaning, and volume fluctuation due to hardening of the secondary mold part are alleviated and absorbed by the elastic primary mold part made of synthetic resin. There is no risk of cracks in the molded part or the core of the transformer.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] A first embodiment of the present invention will be described below with reference to FIGS. The electrostatic coating gun has a structure in which a high voltage generator 20 is housed inside the gun body 10. The gun body 10 is made of a metal material or a conductive synthetic resin material, and includes a barrel portion 11 that is long in the front-rear direction and a grip portion 12 that extends downward from a rear end portion of the barrel portion 11. Gun body 10
In order to release the static electricity charged on the operator to the ground when the operator grips the grip portion 12, the grip portion 1
It is grounded via a cable 13 connected to the lower end of 2. Inside the gun body 10, a paint opening / closing valve 15 and an air opening / closing valve 16 which are elongated in the front-rear direction and which are opened and closed by the operation of the trigger 14 are coaxially arranged in series. The air on-off valve 16 is arranged in the rear end portion of the gun body 10, that is, the upper end portion of the grip portion 12, while being housed in a holding body 17 made of an insulating synthetic resin. The trigger 14 is operated to operate the paint opening / closing valve 15 and the air opening / closing valve 16.
When opened, the paint supplied to the front end of the gun body 10 is applied with a high voltage by the high voltage generator 20, and the gun body 1
It is ejected from the nozzle 18 at the front end of 0 and is applied by electrostatic action to an object to be coated (not shown) in a grounded state. Further, by opening the on-off valve 16 for air, the gun body 10
Pressurized air supplied to the rear end portion reaches the nozzle 18 through the inside of the gun body 10, atomizes the discharged paint, and forms it into a predetermined pattern shape.

Inside the gun body 10, both on-off valves 15,
The high voltage generator 20 is housed so as to be located above 16. The high voltage generator 20 includes a booster circuit (not shown) arranged substantially in the front half thereof and a transformer 21 arranged at the rear end thereof, a case 23 made of an insulating synthetic resin, and a molded portion of the insulating synthetic resin. The structure is accommodated in a housing 22 constituted by 25 and 26. The rear end portion of the housing 22 of the high-voltage generator 20 that houses the transformer 21 (hereinafter referred to as the transformer mold portion 22R) has an upper surface and left and right side surfaces with almost no gap from the inner wall surface of the gun body 10. They are in close proximity to each other.
That is, the transformer 21 is close to the conductive gun body 10. Thus, the conductive gun body 10
Is close to the transformer 21, the gun body 10 influences the magnetic field lines in the transformer 21, and the high voltage generator 20 has a voltage value different from the voltage value originally supposed to occur, or the static voltage of the same configuration. There is a possibility that the voltage value generated between the electric painting guns may vary.

Therefore, as a countermeasure against this, in this embodiment, a metal shield plate 24 (shield layer which is a constituent of the present invention) is attached to the outer surface of the transformer mold portion 22R (a portion corresponding to the transformer 21). Has been. The shield plate 24 is disposed only on the region of the outer surface of the transformer mold portion 22R that is close to the gun body 10, that is, on the upper surface and both left and right side surfaces (see FIG. 3). The thickness of the shield plate 24 is set so that the outer surface thereof is in close contact with the inner wall surface of the gun body 10. This allows
The shield plate 24 is grounded via the gun body 10 and the cable 13.

At the front end of the transformer mold portion 22R, the booster circuit mold portion 2 surrounding the booster circuit is provided.
2F extends forward, so the transformer mold part 2
The shield plate 24 is not provided on the front surface of the 2R. In addition, the rear surface of the transformer mold portion 22R has a gun body 10
Since there is a large space S between the gun body 10
Does not affect the magnetic field lines from the rear, and therefore the shield plate 2 is also provided on the rear surface of the transformer mold portion 22R.
4 is not provided. Furthermore, the transformer mold part 2
Since the lower surface of 2R is in contact with the upper surface of the insulative holding body 17, there is no fear that the gun body 10 will affect the magnetic lines of force from below. Not not.

As described above, the housing 22 is formed by the resin molding so as to surround the transformer 21 and the booster circuit without a gap. Next, the detailed structure of the housing 22 and the molding process will be described. As shown in FIG. 4, the housing 22 is long in the front-rear direction over the entire length of the high-voltage generator 20 (the front portion is omitted in FIG. 4), and the insulating synthetic resin whose bottom surface is open ( For example, case 2 made of polybutylene terephthalate)
3, a primary mold part 25 made of an insulating synthetic resin (for example, urethane) having elasticity, and a secondary mold part 26 made of an insulating synthetic resin (for example, epoxy) having high solvent resistance.
Consists of.

The inside of the case 23 is partitioned by a partition wall 27 into a booster circuit accommodation chamber 28 and a transformer accommodation chamber 29. In the transformer accommodating chamber 29, the transformer 21 is arranged so as to be in contact with the upper surface wall of the case 23, and a primary mold portion 25 (primary mold resin) is filled around the transformer 21 without any gap. Further, on the lower surface which is the opening surface of the transformer accommodating chamber 29, the primary mold portion 2
The entire surface of 5 is the thin film portion 2 of the secondary mold portion 26.
The thin film portion 26A is covered with 6A and constitutes a part of the surface of the housing 22. On the other hand, in the booster circuit accommodating chamber 28, the secondary mold portion 26 (secondary mold resin) is filled around the booster circuit without a gap.

The molding process of the high voltage generator 20 is performed as follows. First, the manufactured case 23 is turned upside down, the transformer 21 is set in the transformer housing chamber 29 (see FIG. 5), and the booster circuit is set in the booster circuit housing chamber 28 (not shown). Then, the case 23 is connected to the primary molding dies 30A, 3
While being set to 0B, the primary mold resin is filled in the transformer housing chamber 29 (see FIG. 6) to mold the primary mold portion 25. Next, the primary mold die 30A,
The case 23 taken out from 30B is set in the secondary molding dies 31A and 31B, and the gap between the surface of the primary molding portion 25 of the transformer accommodation chamber 29 and the secondary molding dies 31A and the boosting circuit accommodation chamber are set. 28 is filled with a secondary molding resin, and the secondary molding portion 26 and the thin film portion 2 are filled.
Mold 6A. As described above, the high voltage generator 20 in which the transformer 21 and the booster circuit are enclosed in the housing 22 by the resin molding is obtained.

As described above, in the present embodiment, the shield plate 24, which is arranged so as to correspond to the transformer 21 and is grounded, is provided in a region of the outer surface of the housing 22 which is close to the conductive gun body 10. With this configuration, the positional relationship between the transformer 21 housed in the housing 22 and the shield plate 24 that is provided on the outer surface of the housing 22 and is in the grounded state is always constant. Therefore,
The high voltage generator 20 of the present embodiment generates a high voltage of a constant value without being affected by the positional relationship with the gun body 10 (that is, regardless of whether or not the gun body 10 is in proximity). Can be made. Further, even when the gun body 10 is made of a conductive synthetic resin material, a high voltage having a constant value can be generated without being influenced by the distribution of the conductors in the resin. As described above, in the electrostatic coating gun according to the present embodiment, the voltage generation value in the high voltage generator 20 fluctuates because the high voltage generator 20 is arranged close to the conductive gun body 10. Is prevented.

Further, even when the transformer 21 suffers a short circuit voltage breakdown, the shield plate 24 surrounding the transformer 21 prevents the discharge of the housing 22 to the outside (upper and left and right sides). Further, even if the secondary mold portion 26 is cracked by an impact, the shield plate 24 prevents the discharge of the housing 22 to the outside (upper and left and right sides). Also, the transformer 2 is made by resin molding
The housing 22 which surrounds the primary molding part 25 is made of an elastic synthetic resin material and covers the transformer 21.
And a secondary mold portion 26 which is made of a synthetic resin material having solvent resistance and which covers the outer surface of the primary mold portion 25 and forms the surface of the housing 22. Play. Since the secondary mold portion 26 forming the surface of the housing 22 has solvent resistance, the primary mold portion 25 and the transformer 21 are prevented from being damaged by the solvent during cleaning. In addition, since the impact due to the drop during use, the heat shock during cleaning, and the volume change due to the hardening of the secondary mold portion 26 are alleviated and absorbed by the elastic primary resin mold portion 25, It is also prevented that the secondary mold portion 26 and the core of the transformer 21 are cracked.

[Other Embodiments] The present invention is not limited to the embodiments described above and illustrated in the drawings. For example, the following embodiments are also included in the technical scope of the present invention. In addition to the above, various modifications can be made without departing from the scope of the invention. (1) In the above embodiment, an example was described in which the present invention was applied to a hand gun used by an operator holding a grip, but the present invention can also be applied to an automatic gun in which the operator does not contact the gun body.

(2) Although the shield layer is made of a metal shield plate in the above-described embodiment, according to the present invention, if the shield layer is conductive, a material other than metal (for example, a conductive resin) is used. It is also possible to use a thin film formed by applying and drying, or a sheet to which a sheet made of a conductive resin material is adhered. (3) In the above-described embodiment, it is provided only on the outer surface of the high voltage generator, which is close to the conductive gun body and is affected by the magnetic lines of force of the transformer (the upper surface and the left and right side surfaces of the high voltage generator). According to the present invention, the shield layer may be provided in a region which is not close to the gun body.

(4) In the above embodiment, the housing has a two-layer structure of a primary mold part and a secondary mold part. However, according to the present invention, the housing is composed of only a primary mold made of a synthetic resin having solvent resistance. You may shape. (5) In the above embodiment, the housing has a structure in which a case is used in addition to the primary mold part and the secondary mold part. However, according to the present invention, only the primary mold part and the secondary mold part are used without using the case. You may comprise.

[Brief description of drawings]

[Figure 1] Cross-sectional view showing the entire electrostatic coating gun

[Figure 2] Partial enlarged cross-sectional view of the electrostatic coating gun

FIG. 3 is a cross-sectional view showing a state in which the high voltage generator is viewed from the rear.

FIG. 4 is a partial sectional view of a high voltage generator.

FIG. 5 is a cross-sectional view showing a step of primary-molding a housing.

FIG. 6 is a sectional view showing a state where the primary molding is completed.

FIG. 7 is a sectional view showing a secondary molding process.

FIG. 8 is a sectional view showing a state where the secondary molding is completed.

[Explanation of symbols]

10 ... Gun body 20 ... High voltage generator 21 ... Transformer 22 ... Housing 24 ... Shield plate (shield layer) 25 ... Primary mold part 26 ... Secondary mold part

Claims (2)

[Claims] 1. Inside a gun body made of a conductive material,
A high voltage generator having a transformer housed in a housing is housed, a high voltage is applied to the paint supplied to the gun body, and the paint is discharged from the gun body to a grounded object. An electrostatic coating gun, wherein the outer surface of the housing is provided with a shield layer arranged corresponding to the transformer and grounded. . 2. An electrostatic coating gun in which the housing is surrounded by a resin mold to surround the transformer, wherein the housing is made of a synthetic resin material having elasticity, a primary mold portion for covering the transformer, and a solvent resistant. The electrostatic coating gun according to claim 1, further comprising: a secondary mold portion that is made of a synthetic resin material having a property of covering the outer surface of the primary mold portion and that forms a surface of the housing. .