JPH0522051U - Spray gun for painting - Google Patents

Abstract

(57) [Abstract] [Purpose] To enhance the restoring force of the needle electrode and prevent the needle electrode from being deformed by external force. [Structure] The needle electrode 21 is formed by twisting a plurality of thin metal wires 22 having spring properties and conductivity. As a result, the restoring force of the needle electrode 21 is increased, and the elastic limit is increased. When the paint nozzle 4 and the air nozzle 5 are replaced or washed, the nozzles 4 and 5 come into contact with the tip 21A of the needle-shaped electrode 21 due to carelessness of the operator.
When the needle electrode 21 is deformed, it returns to its original shape by its own elastic force.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a coating spray gun for spraying a coating material onto an object to be coated such as an automobile.

[0002]

[Prior Art]

 3 to 5, an air atomization type automatic electrostatic coating spray gun will be described as an example of a conventional coating spray gun.

In the figure, reference numeral 1 denotes a spray gun body formed of an insulating resin material in a long cylindrical shape, and the outer peripheral side of the spray gun body 1 is covered with a spray gun cover 2. Reference numeral 3 denotes a nozzle main body provided on the tip side of the spray gun main body 1. The nozzle main body 3 is formed of an insulating resin material in a stepped cylindrical shape. Further, a valve accommodating portion 3A forming a valve casing of a paint valve 7 described later is formed on the base end side of the nozzle body 3.

Reference numeral 4 denotes a paint nozzle that is screwed to the center of the tip side of the nozzle body 3 and is formed in a stepped tubular shape from an insulating resin material. The paint nozzle 4 is located in the central portion and extends in the axial direction. A guide cylinder portion 4A which is formed by being extended and is provided with a needle valve body 7C of a paint valve 7 described later so as to be movable, and an atomizing air passage 4B formed on the outer peripheral side of the guide cylinder portion 4A. It is roughly configured and a paint spray port 4C is integrally formed on the tip end side of the guide cylinder portion 4A.

Reference numeral 5 denotes an air nozzle that is provided so as to cover the tip side of the paint nozzle 4 and is fixed to the tip side of the spray gun body 1 via a retainer ring 6, and the tip outer peripheral side of the air nozzle 5 is , A pair of horn portions 5A, 5A are provided facing each other. Further, a plurality of atomizing air ejection ports 5B, 5B, ... (Only two are shown) are formed on the inner peripheral side of the tip of the air nozzle 5 so as to surround the paint spraying port 4C of the paint nozzle 4. A plurality of pattern air ejection ports 5C, 5C, ... (Only two are shown) are formed in each horn portion 5A. Then, the air nozzle 5 ejects atomization air from each atomization air ejection port 5B, thereby promoting atomization of the paint sprayed from the paint spray port 4C of the paint nozzle 4 and atomizing the atomization air. Pattern air is sprayed onto the paint from each pattern air ejection port 5C to form the spray pattern of the paint into an elliptical or oval shape.

Reference numeral 7 denotes a paint valve provided in the valve accommodating portion 3A of the nozzle body 3, and the paint valve 7 has a valve chamber 7A formed in the valve accommodating portion 3A and a shaft inside the valve chamber 7A. And a piston 7B that is slidable in the direction and defines the inside of the valve chamber 7A into two air chambers A and B, the base end side is fixed to the central portion of the piston 7B, and the tip side is the paint of the paint nozzle 4. A needle valve body 7C as an electrode holding rod extending in the direction of the spray port 4C and formed of an insulating material such as ceramics into a long cylindrical shape, and a base end side of the valve chamber 7A are covered. The valve chamber 7A is covered with a cylindrical guide 8 and a V packing 9 in a gas-liquid-tight manner at the tip side of the valve chamber 7A. ing. A plug 10 made of a conductive material is screwed to the base end side of the piston 7B, and a power supply spring 11 is provided between the plug 10 and the closing portion 7D.

Reference numerals 12 and 13 respectively denote one side supply / discharge port and the other side supply / discharge port provided in the valve accommodating portion 3 A of the nozzle body 3, and the one side supply / discharge port 12 closes the piston 7 B of the paint valve 7. The air chamber A is communicated with the portion 7D, and the other side supply / discharge port 13 is communicated with the air chamber B between the piston 7B and the cylindrical guide 8. By supplying / discharging compressed air into / from the air chambers A, B from the supply / discharge ports 12, 13, the piston 7B of the paint valve 7 slides and the needle valve body 7C opens and closes. ing.

Reference numeral 14 denotes a needle-shaped electrode which is positioned at the axial center of the needle valve body 7C and is axially inserted into the needle valve body 7C. The tip 14A side of the needle-shaped electrode 14 is also shown in FIG. As shown, it projects forward from the paint spray port 4C of the paint nozzle 4, and the base end 14B side is fixed to the piston 7B of the paint valve 7 by the plug 10. The needle-shaped electrode 14 is formed of a conductive metal material such as stainless steel into a single wire. The needle electrode 14 forms a corona discharge region in front of the paint spray port 4C of the paint nozzle 4 by applying a high voltage from a high voltage generator 18 described later, and the corona discharge region causes the corona discharge region. This is to charge the sprayed paint.

Reference numerals 15 and 16 respectively denote a paint supply passage and a paint discharge passage formed in the spray gun body 1, and the tip ends of the passages 15 and 16 communicate with the inside of the guide cylinder portion 4 A of the paint nozzle 4 to form a base. The end side is connected to a color changing valve device (not shown) installed outside the spray gun body 1.

Reference numeral 17 denotes a power plug provided at the base end side of the nozzle body 3 and provided inside the spray gun body 1, and 18 denotes a power plug located at the base end side of the power feed plug 17 and fitted inside the spray gun body 1. The installed high voltage generator is shown, and the high voltage generator 18 is composed of a multiple voltage circuit, a high voltage resistor (neither shown), and the like. The high voltage generator 18 has its base end connected to an external power source (not shown) and its tip connected to the power supply plug 17. Then, the high voltage generator 18 boosts the voltage from the external power source to a high voltage of, for example, about −60 kV, and the high voltage is passed through the power plug 17, the closing portion 7D, the power supply spring 11, etc. It is applied to the electrode 14.

The coating spray gun according to the present embodiment has the above-described structure, and the paint discharged from the color change valve device flows into the guide tube portion 4 A of the paint nozzle 4 via the paint supply passage 15. To do. Next, when compressed air is supplied into the air chamber B from the other side supply / discharge port 13 and air in the air chamber A is discharged from the one side supply / discharge port 12, the piston 7B of the paint valve 7 is closed. The needle valve body 7C is opened by moving toward the portion 7D side, and the paint filled in the guide cylinder portion 4A is sprayed from the paint spraying port 4C of the paint nozzle 4. Then, this paint is atomized by the atomizing air ejected from each atomizing air ejection port 5B of the air nozzle 5, and the spray pattern is elliptical by the pattern air ejected from each pattern air ejection port 5C. Shaped or oval shaped.

On the other hand, a high voltage from a high voltage generator 18 is applied to the needle-shaped electrode 14 via the power supply plug 17, the closing portion 7D, etc., and a corona discharge region is formed on the tip 14A side of the needle-shaped electrode 14. It is formed. Then, the paint sprayed from the paint spray port 4C is charged by passing through the corona discharge region, flies toward the article to be connected to the ground potential, and adheres to the surface of the article to be coated.

[0013]

[Problems to be solved by the device]

 By the way, in the above-mentioned conventional coating spray gun, since the needle-shaped electrode 14 is formed of a conductive metal material such as stainless steel into a single wire-like shape, the restoring force of the needle-shaped electrode 14 itself ( When the elastic force) is low and an external force exceeding this restoring force is applied, it will deform (plastic deformation) beyond the elastic limit. Therefore, when the paint nozzle 4 and the air nozzle 5 are replaced or washed, the nozzles 4 and 5 and the cleaning tool contact and collide with the tip 14A of the needle electrode 14 due to carelessness of the operator. When the needle-shaped electrode 14 is deformed, the needle-shaped electrode 14 cannot be restored to its original shape by using a tool such as pliers on the spot, and as shown in FIG. 14A is eccentric by the dimension d from the original central axis OO (central axis of the paint nozzle 4 and the needle valve body 7C).

For this reason, in the above-described conventional technique, the spray pattern of the paint discharged from the paint spray port 4C of the paint nozzle 4 is changed, or the paint is not sufficiently atomized by the atomizing air. There is a problem that it adheres to the object to be coated, resulting in poor coating and significantly lowering the coating quality. Also, once the needle-shaped electrode 14 is deformed, it is necessary to disassemble the spray gun for painting and install a new needle-shaped electrode 14 or replace it with a new spray gun. There is a problem that work efficiency is significantly reduced.

The present invention has been made in view of the above-mentioned problems of the prior art, and is a coating that can enhance the restoring force of the needle electrode and effectively prevent the needle electrode from being deformed by an external force. It aims at providing the spray gun for.

[0016]

[Means for Solving the Problems]

 A feature of the configuration adopted by the present invention to solve the above-mentioned problems is that the needle-shaped electrode is formed by twisting a plurality of metal thin wires having spring properties and conductivity.

[0017]

[Action]

 Since a plurality of thin metal wires having elasticity and conductivity are twisted together, the restoring force of the entire needle-shaped electrode is increased, and the elastic limit can be increased.

[0018]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. In addition, in the embodiment, the same components as those of the above-described conventional technique are designated by the same reference numerals, and the description thereof will be omitted.

In the figure, reference numeral 21 denotes a needle electrode according to the present embodiment which is located on the central axis OO of the needle valve body 7C and is axially inserted into the needle valve body 7C. Similar to the needle electrode 14 described in the prior art, the electrode 21 has a tip 21A side protruding forward from the paint spray port 4C of the paint nozzle 4, and a base end (not shown) side having the plug 10 attached thereto. It is fixed to the piston 7B via. However, as shown in FIG. 2, the needle electrode 21 has a small diameter formed by twisting, for example, about 20 to 30 thin metal wires 22, 22, ... It is formed in a bar shape, and the front end 21A side and the base end side are formed by silver brazing 23 so that each thin metal wire 22 does not come apart (only the front end side is shown).

The coating spray gun according to this embodiment has the above-described structure, and its basic operation is not significantly different from that of the prior art.

However, according to the present embodiment, since the needle-shaped electrode 21 is formed by twisting a plurality of thin metal wires 22 having spring property and conductivity, the restoring force of the needle-shaped electrode 21 is set. Can be increased, and the elastic limit can be effectively increased. As a result, when the coating nozzle 4 and the air nozzle 5 are replaced or washed, the nozzles 4 and 5 are inadvertently brought into contact with the tip 21A of the needle electrode 21 due to the operator's carelessness. Even if the electrode 21 is deformed (elastically deformed) as shown by the chain double-dashed line in FIG. 1, it can be easily restored to its original shape, and the paint sprayed from the paint spray port 4C of the paint nozzle 4 can be sprayed. It can effectively prevent the pattern and the atomized state of the paint from changing due to atomized air, and stabilize the coating quality for a long time. In addition, the maintainability can be greatly improved and the painting efficiency can be improved.

In the above embodiment, the stainless wire is used as an example of the metal fine wire, but the present invention is not limited to this, and other thin wire made of a material having spring property and conductivity such as nickel alloy may be used. You may use a metal fine wire.

Further, in the above-described embodiment, the tip 21A side of the needle-shaped electrode 21 is described as being molded and fixed by the silver brazing 23 so that the metal thin wires 22 are not separated, but instead of this, for example, a small diameter is used. A metallic cap may be externally fitted to the tip 21A so that the thin metal wires 22 do not come apart.

Furthermore, in the above-mentioned embodiment, it has been described that about 20 to 30 thin metal wires 22 are twisted together, but the present invention is not limited to this, and for example, 20 or less, 30 or more may be used. Of.

Furthermore, in the above-described embodiment, the case of using the spray gun for electrostatic spraying of the air atomization type has been described as an example, but the electrostatic spraying of the hydraulic atomization type and the hydraulic mix atomization type is described. It can be widely applied not only to the spray gun for painting but also to a manually operated spray gun for manually opening and closing the needle valve body. Further, as shown in Japanese Utility Model Laid-Open No. Sho 58-14 1756, for example, the present invention can be applied to a spray gun for painting in which a paint valve is separately provided and an electrode holding rod is fixedly arranged.

[0026]

[Effect of the device]

 As described above in detail, according to the present invention, since the needle-shaped electrode is formed by twisting a plurality of metal thin wires having spring property and conductivity, the restoring force of the entire needle-shaped electrode is effectively increased. The elastic limit can be improved. As a result, even if an external impact is applied to the needle-shaped electrode, the needle-shaped electrode can be quickly restored to its original shape, and the spray pattern of the paint sprayed from the paint spray port of the paint nozzle changes. Can be prevented and the coating quality can be stabilized for a long period of time. In addition, the maintainability can be improved and the coating efficiency can be improved.

[Brief description of drawings]

FIG. 1 is an enlarged vertical sectional view showing a main part of a spray gun for painting according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view showing an enlarged tip side of a needle-shaped electrode in FIG.

FIG. 3 is a vertical cross-sectional view showing a main part of a conventional spray gun for painting.

4 is a longitudinal sectional view of an essential part showing an enlarged view of a needle electrode, a needle valve body and the like in FIG.

FIG. 5 is a longitudinal sectional view of a main part showing a deformed state of the needle-shaped electrode in FIG.

[Explanation of symbols]

 1 Spray gun body 3 Nozzle body 4 Paint nozzle 4C Paint spray port 7 Paint valve 7C Needle valve body (electrode holding rod) 21 Needle-shaped electrode 22 Metal thin wire

Claims (1)

[Scope of utility model registration request] 1. A spray gun body, a nozzle body provided on the tip side of the spray gun body, a paint nozzle provided on the tip side of the nozzle body for spraying paint from a paint spray port, and the nozzle body. An electrode holding rod having a tip extending to the paint spray port, the needle-shaped electrode being inserted in the axial direction of the electrode holding rod and having a tip side protruding from the electrode holding rod. In the coating spray gun, the needle electrode is formed by twisting a plurality of metal thin wires having spring properties and conductivity.