JP4623876B2 - Electrostatic painting gun - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrostatic coating gun.
[0002]
[Prior art]
Electrostatic painting guns are equipped with a high voltage generator inside the gun body, applying high voltage to the paint supplied to the gun body, discharging the paint, and applying it to the grounded object. ing. There are multiple types of gun bodies with different shapes and dimensions depending on the purpose of use, etc. High voltage generators are also available with multiple types of shapes and dimensions depending on the voltage applied to the paint. They are used in appropriate combinations according to the coating conditions.
[0003]
[Problems to be solved by the invention]
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 worker's body to the ground. Therefore, when the high voltage generator is assembled at 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, and the high voltage generator is originally generated. The voltage value may be different from the expected voltage value. Even when comparing electrostatic coating guns with the same combination of high voltage generator and gun body, if the gun body is made of a conductive synthetic resin material, the distribution of conductors in the resin Since the method slightly affects the magnetic field lines of the transformer, there is a possibility that the voltage value generated between the electrostatic coating guns varies.
[0004]
The present invention was invented in view of the above circumstances, and prevents the voltage generation value in the high voltage generator from fluctuating due to the high voltage generator being disposed in proximity to the gun body made of a conductive material. The purpose is to do.
[0005]
[Means for Solving the Problems]
The invention of claim 1 comprises a gun main body made of a conductive material and a high voltage generator provided with a transformer housed in a housing, wherein a high voltage is applied to the paint supplied to the gun main body. An electrostatic coating gun in which the paint is discharged from the gun body and applied to a grounded object , wherein the housing surrounds the transformer by a resin mold. In the coating gun , the outer surface of the housing is provided with a shield layer arranged to correspond to the transformer and grounded, and the housing is made of a synthetic resin material having elasticity and covers the transformer. A primary molding part and a secondary molding made of a synthetic resin material having solvent resistance and covering the outer surface of the primary molding part and forming the surface of the housing It is constituted by a part.
[0006]
According to a second aspect of the present invention, a high voltage generator having a transformer housed in a housing is housed in a gun body made of a conductive material, and a high voltage is applied to the paint supplied to the gun body. In the electrostatic coating gun in which the paint is discharged from the gun body and applied to the grounded object, the grip portion is formed of a conductive resin and the grip portion is grounded. The outer surface of the housing is provided with a shield layer arranged so as to correspond to the transformer and grounded.
[0007]
[Action and effect of the invention]
[Invention of Claim 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 always constant. Therefore, the high voltage generator generates a high voltage of a certain value regardless of whether or not it is arranged close to the gun body.
Furthermore, since the secondary mold part which comprises the surface of a housing has solvent resistance, a primary mold part and a transformer are not attacked by the solvent at the time of washing | cleaning. In addition, impacts due to drops during use, heat shocks during cleaning, and volume fluctuations associated with curing of the secondary mold part are alleviated and absorbed by the primary mold part made of elastic synthetic resin. There is no risk of cracking in the mold part or the core of the transformer.
[Invention of claim 2]
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 always constant. Therefore, the high voltage generator generates a high voltage of a certain value regardless of whether or not it is arranged close to the gun body.
Further, even when the transformer causes a short-circuit voltage breakdown, the shield layer prevents discharge to the outside of the housing.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
[Embodiment 1]
A first embodiment of the present invention will be described below with reference to FIGS.
The electrostatic coating gun has a configuration in which a high voltage generator 20 is accommodated 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 the rear end portion of the barrel portion 11. The gun body 10 is grounded via a cable 13 connected to the lower end of the grip portion 12 in order to release static electricity charged to the worker to the ground when the worker grips the grip portion 12. Inside the gun body 10, a paint on-off valve 15 and an air on-off valve 16 that are elongated in the front-rear direction and are opened and closed by the operation of the trigger 14 are arranged in series in a coaxial manner. The air on-off valve 16 is disposed at the rear end portion of the gun body 10, that is, the upper end portion of the grip portion 12, while being accommodated in a holding body 17 made of an insulating synthetic resin. When the paint 14 is opened by opening the paint on-off valve 15 and the air on-off valve 16, 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 front end of the gun body 10 is applied. Are applied by electrostatic action to an object (not shown) discharged from the nozzle 18 and grounded. The pressurized air supplied to the rear end of the gun body 10 by opening the air on-off valve 16 reaches the nozzle 18 through the gun body 10 and atomizes the paint to be discharged. Mold into a pattern shape.
[0009]
Inside the gun body 10, a high voltage generator 20 is accommodated so as to be positioned above both the on-off valves 15 and 16. The high voltage generator 20 includes a step-up circuit (not shown) disposed in a substantially first half portion thereof and a transformer 21 disposed in a rear end portion of a case 23 made of an insulating synthetic resin and a molding portion of the insulating synthetic resin. The structure is accommodated in a housing 22 constituted by 25 and 26.
The rear end portion (hereinafter referred to as transformer mold portion 22R) that houses the transformer 21 in the housing 22 of the high-voltage generator 20 has an upper surface and both left and right side surfaces almost spaced from the inner wall surface of the gun body 10. They are in close proximity. That is, the transformer 21 is close to the conductive gun body 10. Thus, when the conductive gun body 10 is close to the transformer 21, the gun body 10 affects the magnetic field lines in the transformer 21, which is different from the voltage value that the high voltage generator 20 should originally generate. There is a possibility that the voltage value may vary or the voltage value generated between electrostatic coating guns having the same configuration may vary.
[0010]
Therefore, as a countermeasure, in the present embodiment, a metal shield plate 24 (shield layer which is a constituent element of the present invention) is attached to the outer surface of the transformer mold portion 22R (portion corresponding to the transformer 21). . The shield plate 24 is disposed only on the outer surface of the transformer mold portion 22R, in the region close to the gun body 10, that is, on the upper surface and the 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. Thereby, the shield plate 24 is grounded via the gun body 10 and the cable 13.
[0011]
At the front end of the transformer mold portion 22R, the booster circuit mold portion 22F that surrounds the booster circuit extends forward, so that the shield plate 24 is not provided on the front surface of the transformer mold portion 22R. Also, since the rear surface of the transformer mold part 22R has a large space S between the gun body 10 and the gun body 10, there is no possibility that the gun body 10 will affect the magnetic field lines from the rear, and therefore, the rear surface of the transformer mold part 22R The shield plate 24 is not provided. Further, since the lower surface of the transformer mold portion 22R is in contact with the upper surface of the insulating holding body 17, there is no possibility that the gun body 10 will affect the magnetic field lines from below, and therefore the lower surface of the transformer mold portion 22R is shielded. The plate 24 is not provided.
[0012]
As described above, the housing 22 is configured to enclose the transformer 21 and the booster circuit without gaps by resin molding. Next, a detailed structure of the housing 22 and a 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 side portion is omitted in FIG. 4), and an insulating synthetic resin (the lower surface is opened) For example, a case 23 made of polybutylene terephthalate), a primary mold part 25 made of an insulating synthetic resin (for example, urethane) having elasticity, and a secondary made of an insulating synthetic resin (for example, epoxy) having a high solvent resistance. It consists of a mold part 26.
[0013]
The interior of the case 23 is partitioned into a booster circuit accommodation chamber 28 and a transformer accommodation chamber 29 by a partition wall 27. In the transformer accommodating chamber 29, the transformer 21 is disposed so as to contact the upper surface wall of the case 23, and the primary mold portion 25 (primary mold resin) is filled around the transformer 21 without a gap. In addition, on the lower surface, which is the opening surface of the transformer accommodating chamber 29, the surface of the primary mold portion 25 is entirely covered with the thin film portion 26 </ b> A of the secondary mold portion 26. Constitutes part of the surface. On the other hand, in the booster circuit accommodating chamber 28, the secondary mold portion 26 (secondary mold resin) is filled without any gap around the booster circuit.
[0014]
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 set in the primary molds 30A and 30B, and the primary mold resin is filled in the transformer accommodating chamber 29 (see FIG. 6), and the primary mold portion 25 is formed. Next, the case 23 taken out from the primary molding dies 30A and 30B is set in the secondary molding dies 31A and 31B, and the surface of the primary molding portion 25 of the transformer accommodating chamber 29 and the secondary molding dies 31A are set. The secondary mold resin is filled in the gap between the first and second pressure booster circuit accommodating chambers 28, and the secondary mold part 26 and the thin film part 26A are formed. As described above, the high voltage generator 20 in which the transformer 21 and the booster circuit are surrounded by the housing 22 by the resin mold is obtained.
[0015]
As described above, in the present embodiment, the shield plate 24 that is arranged so as to correspond to the transformer 21 and is grounded is provided in a region close to the conductive gun body 10 on the outer surface of the housing 22. The positional relationship between the transformer 21 accommodated in the housing 22 and the shield plate 24 provided on the outer surface of the housing 22 and grounded is always constant. Therefore, the high voltage generator 20 of the present embodiment is not affected by the positional relationship with the gun body 10 (that is, regardless of whether or not the gun body 10 is close to the gun body 10). Can be generated. Further, even when the gun body 10 is made of a conductive synthetic resin material, a high voltage having a certain value can be generated without being affected by the manner of distribution of the conductors in the resin. Thus, in the electrostatic coating gun of the present embodiment, the voltage generation value in the high voltage generator 20 fluctuates due to the high voltage generator 20 being arranged close to the conductive gun body 10. Is prevented.
[0016]
Further, even when the transformer 21 has a short-circuit voltage breakdown, the shield plate 24 surrounding the transformer 21 prevents discharge to the outside of the housing 22 (upward and left and right sides). Furthermore, even if a crack occurs in the secondary mold portion 26 due to an impact, the shield plate 24 prevents discharge to the outside of the housing 22 (upward and left and right sides).
The housing 22 that surrounds the transformer 21 with a resin mold is made of a synthetic resin material having elasticity, and covers the outer surface of the primary mold part 25 made of a synthetic resin material having solvent resistance. In addition, the secondary mold portion 26 that forms the surface of the housing 22 is provided, and this produces the following effects. Since the secondary mold part 26 constituting the surface of the housing 22 has solvent resistance, the primary mold part 25 and the transformer 21 are prevented from being attacked by the solvent during cleaning. In addition, since the impact due to dropping or the like during use, the heat shock at the time of cleaning, and the volume fluctuation accompanying the curing of the secondary mold part 26 are alleviated and absorbed by the primary mold part 25 made of synthetic resin having elasticity, It is also prevented that the secondary mold part 26 and the core of the transformer 21 are cracked.
[0017]
[Other Embodiments]
The present invention is not limited to the embodiment described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention, and further, within the scope not departing from the gist of the invention other than the following. Various modifications can be made.
(1) Although the above embodiment has been described with reference to an example in which the worker applies to a hand gun used by gripping the grip, the present invention can also be applied to an automatic gun in which the operator does not contact the gun body.
[0018]
(2) In the above embodiment, the shield layer is a metal shield plate. However, according to the present invention, the shield layer is other than metal (for example, by applying a conductive resin) as long as it is conductive. And a film formed by drying and a sheet made of a conductive resin material) can be used.
(3) In the above embodiment, the high voltage generator is provided only on the outer surface of the high voltage generator close to the conductive gun body and affected by the magnetic field lines of the transformer (upper surface and both left and right side surfaces of the high voltage generator). According to the present invention, a shield layer may also be provided in a region not close to the gun body.
[0019]
(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 molded only by a primary mold made of a synthetic resin having solvent resistance. Also good.
(5) In the above embodiment, the housing has a structure using a case 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 the drawings]
[Fig. 1] Cross-sectional view of the entire electrostatic coating gun [Fig. 2] Partial enlarged cross-sectional view of the electrostatic coating gun [Fig. 3] Cross-sectional view of the high voltage generator as seen from the rear [Fig. 4] High FIG. 5 is a sectional view showing a process of primary molding of 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. ] Cross-sectional view showing the completed secondary mold
DESCRIPTION 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)

A high voltage generator having a transformer housed in a housing is housed inside a gun body made of a conductive material, a high voltage is applied to the paint supplied to the gun body, and the paint is applied to the gun body. In an electrostatic coating gun that is discharged from and applied to a grounded object, the housing is configured to surround the transformer by a resin mold ,
The outer surface of the housing is provided with a shield layer arranged so as to correspond to the transformer and grounded ,
The housing is made of an elastic synthetic resin material and covers the transformer, and the secondary mold is made of a solvent-resistant synthetic resin material and covers the outer surface of the primary mold portion and forms the surface of the housing. electrostatic spray gun, characterized in that it is constituted by a part. A high voltage generator having a transformer housed in a housing is housed inside a gun body made of a conductive material, a high voltage is applied to the paint supplied to the gun body, and the paint is applied to the gun body. In electrostatic coating guns that are discharged from and applied to grounded objects,
The grip part is made of conductive resin, and the grip part is grounded.
An electrostatic coating gun, wherein an outer surface of the housing is provided with a shield layer arranged to correspond to the transformer and in a grounded state.

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