JP2772590B2 - Spray gun for painting - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spray gun for coating which is suitable for spraying a coating on an object to be coated. 2. Description of the Related Art Generally, a spray gun for electrostatic coating includes a spray gun body, a nozzle body provided at a tip side of the spray gun body, and a spray body provided at a tip side of the nozzle body to apply paint. A paint nozzle to be sprayed; an air nozzle provided at the tip of the paint nozzle for spraying atomizing air and pattern air; and a base end side of the nozzle body provided with a needle valve element for supplying and discharging compressed air to move the needle valve body to the paint. A paint valve that opens and closes with respect to the nozzle, and a needle-like electrode that is provided in the needle valve body with a tip end protruding outside from the paint nozzle and that applies a high voltage to the sprayed paint, are roughly constituted. The spray gun body is provided with a paint passage connected to an external paint supply source via a paint supply pipe, and the nozzle body has a substantially U-shaped cross-section formed by annularly cutting the outer peripheral side. An annular paint passage having a U-shape is provided, the opening side of the annular paint passage communicates with the paint passage of the spray gun body, and the bottom side of the annular paint passage communicates with the inside of the paint nozzle. O-rings are mounted on the outer peripheral side of the nozzle body on both sides of the annular paint passage. Each of the O-rings allows paint in the annular paint passage to pass through a gap between the nozzle body and the spray gun body. Prevents leakage. When the needle valve of the paint valve is opened and closed by the supply and exhaust of compressed air, the paint supplied from the paint supply source into the paint nozzle through the paint supply pipe, the paint passage, and the annular paint passage is removed. The paint is sprayed from a paint spray port of the paint nozzle toward an external object to be coated. Here, the paint is atomized by the atomizing air ejected from the air nozzle, and then formed into an oval or oval pattern by the pattern air ejected from the air nozzle. Further, a predetermined high voltage (for example, -60 kV) is supplied to the needle electrode from a high voltage generator, and a corona discharge region is formed on the tip side of the needle electrode. The paint is charged by the corona discharge region, flies toward the object connected to the ground, and is applied to the object. In the above-mentioned conventional spray gun for coating, since O-rings are mounted on both sides of the annular paint passage of the nozzle body, the paint in the annular paint passage is provided. Can be prevented from leaking from the gap between the nozzle body and the spray gun body. However, since two annular gaps are formed between the nozzle body and the spray gun body on both sides of the annular paint passage and surround the outer peripheral side of the nozzle body, paint penetrates into each of these annular gaps. This causes a problem that paint pools occur. Therefore, in the above-mentioned prior art, a cleaning solvent such as a thinner is supplied from a paint supply pipe into the paint nozzle through the paint passage and the annular paint passage in order to clean the paint in the paint nozzle and each paint passage. However, since it is difficult to wash and remove the paint pool generated in the annular gap, not only is a large amount of a washing solvent required, the washing cost is increased, but also a large amount of washing waste liquid is generated, and the coating environment is greatly reduced. There is a problem that it gets worse. In addition, there is a problem that it takes time for the cleaning operation and the color changing operation, and the operation efficiency of each of these operations is significantly reduced. SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and it is possible to reduce the accumulation of paint between a nozzle body and a spray gun body as much as possible. It is an object of the present invention to provide a coating spray gun capable of improving the paint spray. [0008] In order to solve the above-described problems, the present invention employs a spray gun main body having a flange portion formed on the front end side, and a spray gun main body having a flange formed on the front end side of the spray gun main body. A nozzle body provided with a flange portion on the base end side, which is in contact with the flange portion of the spray gun body; a paint nozzle provided on the tip end side of the nozzle body for spraying paint; and a tip of the paint nozzle. An air nozzle that is provided on the side and ejects atomizing air and pattern air, and a paint valve that is provided on the base end side of the nozzle body and opens and closes a needle valve body with respect to the paint nozzle by supply and discharge of compressed air,
A paint passage provided at a tip side of the spray gun body, an outlet opening at a flange portion of the spray gun body, and an inlet connected to an external paint supply source via a paint supply pipe; The paint body is provided in the nozzle body, the inflow port is open to the flange portion of the nozzle body, the outflow port is provided on the other side paint passage communicating with the inside of the paint nozzle, and is provided between the spray gun body and the nozzle body, It comprises a positioning member for positioning and communicating the one-side paint passage and the other-side paint passage. The paint passage on one side and the paint passage on the other side are positioned by a positioning member, and the outlet of the paint passage on one side and the other side are located between the flange of the spray gun body and the flange of the nozzle body. The inlet of the paint passage communicates. The paint discharged from the external paint supply source flows into the one-side paint passage from the paint supply pipe, and is supplied from the one-side paint passage into the paint nozzle via the other-side paint passage. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 3 by taking an example in which the present invention is applied to an electrostatic spray gun for coating. In FIG. 1, reference numeral 1 denotes a spray gun cover formed in a tubular shape from an insulating resin material, and 2 denotes a spray gun cover provided in the spray gun cover 1 so as to extend in the axial direction. The spray gun main body 2 is formed integrally with a cylindrical portion 2A extending inside the spray gun cover 1 and at the tip side of the cylindrical portion 2A, and protrudes from the spray gun cover 1. And a large-diameter cylindrical portion 2B provided at the front end of the large-diameter cylindrical portion 2B. An annular flange portion 2C which abuts against a flange portion 4C of a nozzle body 4 described later, A mounting hole 2D formed in the axial direction is provided on the inner peripheral side of 2C. Further, a base end side of the cylindrical portion 2A is covered with an end cover 3, and a plurality of slits 2E, 2E,.
Are integrally formed so as to protrude radially outward. Reference numeral 4 denotes a nozzle body provided at the tip end of the large-diameter cylindrical portion 2B of the spray gun body 2 and formed in a stepped cylindrical shape from an insulating resin material. The nozzle body 4 is shown in FIGS. As shown, a large-diameter portion 4A fixed to the tip end of the large-diameter cylindrical portion 2B of the spray gun main body 2 by a fixing ring 14 described later.
And a small-diameter portion 4B which is integrally formed so as to protrude in the axial direction from the base end side of the large-diameter portion 4A and is fitted into the mounting hole 2D of the spray gun main body 2, and is substantially constituted by the large-diameter portion 4A. An annular flange portion 4C that abuts with the flange portion 2C of the spray gun main body 2 is integrally formed on the base end side. Also,
As shown in FIG. 3, atomizing air inlets 4D, 4D, pattern air inlets 4E, 4E and the like are formed on the outer peripheral side of the flange portion 4C. Reference numeral 5 denotes a paint nozzle provided on the tip end side of the nozzle body 4. The paint nozzle 5 is formed at the center in the axial direction, and a needle valve body 7C of a paint valve 7 described later is movably provided. Guide tube portion 5A, and guide tube portion 5A
And an atomizing air flow passage 5B formed on the outer peripheral side of the guide tube portion 5A.
Are integrally formed. When the needle valve 7C is opened, the paint nozzle 5 is moved to the guide cylinder 5A.
The paint supplied into the inside is sprayed toward an external object to be coated. Reference numeral 6 denotes an air nozzle which is screwed to the large diameter portion 4A of the nozzle body 4 so as to cover the paint nozzle 5, and a pair of horn portions 6A are integrally formed at the tip end of the air nozzle 6. . Also, on the tip side of the air nozzle 6,
A plurality of atomizing air jets 6B, 6B, ... (only two are shown)
Are formed on the outer peripheral side of the paint spray port 5C of the paint nozzle 5, and each horn portion 6A is formed with a pattern air ejection port 6C. And the air nozzle 6 is
By spraying the atomizing air from each atomizing air outlet 6B, the atomization of the paint sprayed from the paint spraying port 5C of the paint nozzle 5 is promoted, and the atomized air is sprayed onto each pattern air outlet 6C. Is used to form a spray pattern into an elliptical shape or an oval shape by blowing pattern air. Reference numeral 7 denotes a paint valve provided in the small diameter portion 4B of the nozzle body 4. The paint valve 7 includes a valve chamber 7A formed in the small diameter portion 4B of the nozzle body 4 and a valve chamber 7A. And a piston 7B made of a conductive material that defines the inside of the valve chamber 7A into two air chambers A and B, and a piston 7B made of an insulating material such as ceramics.
A needle valve element 7C fixed to the center of the nozzle and extending to the paint spray port 5C of the paint nozzle 5; and a cover formed on the base end side of the valve chamber 7A. The valve chamber 7A is covered with a cylindrical guide 7E and a seal packing 7F. A power supply spring 8 is disposed between the closing portion 7D and the piston 7B. Reference numeral 9 denotes a needle-like electrode provided in the needle valve body 7C in the axial direction, and the tip side of the needle-like electrode 9 protrudes outside from the tip of the needle valve body 7C. The needle-shaped electrode 9 forms a corona discharge region and charges the sprayed paint when a predetermined high voltage is supplied from a high-voltage generator 15 described later. Reference numeral 10 denotes a spiral pipe as a paint supply pipe provided on the outer peripheral side of the spray gun main body 2. An inlet 10A of the spiral pipe 10 has a color change as an external paint supply source through an end cover 3. The outlet 10B is connected to a valve device (not shown), and the outlet 10B is connected to an inlet 11A of the one-side paint passage 11 described later. Reference numeral 11 denotes a large-diameter cylindrical portion 2B of the spray gun body 2.
The inlet 11A of the one-side paint passage 11 is connected to the outlet 10B of the spiral pipe 10, and the outlet 11B is open to the flange portion 2C of the spray gun body 2. . Reference numeral 12 denotes another paint passage formed in the large diameter portion 4A of the nozzle body 4. The inlet 12A of the other paint passage 12 opens to the flange portion 4C of the nozzle body 4, and the outlet 12B. Communicates with the inside of the guide cylinder 5A of the paint nozzle 5. Reference numeral 13 denotes a flange 2 of the spray gun body 2.
C shows a positioning member provided between C and the flange portion 4C of the nozzle body 4, and the positioning member 13 is a fitting hole 13A formed on the outer peripheral side of the flange portion 4C of the nozzle body 4.
And a positioning pin 13B opposed to the fitting hole 13A and fixed to the flange portion 2C of the spray gun main body 2. The positioning member 13 is configured such that the positioning pin 13B is fitted into the fitting hole 13A, thereby the outlet 11B of the one-side paint passage 11 and the other-side paint passage 1 are fitted.
The second inlet 12A is positioned and communicated with the second inlet 12A. Reference numeral 14 denotes a large-diameter cylindrical portion 2B of the spray gun body 2.
FIG. 2 shows a fixing ring screwed on the distal end side,
The nozzle body 4 is provided so as to cover the outer peripheral side of the flange portion 4C of the nozzle body 4, and the nozzle body 4 is
It is fixed to. Reference numeral 15 denotes a high-voltage generating section fitted in the cylindrical portion 2A of the spray gun main body 2, and the high-voltage generating section 15 is provided with a high-voltage generating circuit including a multiplying voltage circuit and the like for security. It is composed of high-voltage resistors (both not shown). The input side of the high-voltage generating unit 15 is connected to a lead wire 16.
Is connected to an external power supply (not shown) via an interface, and the output side is connected to the brush 17. Then, the high voltage generator 1
Numeral 5 converts a voltage supplied from an external power supply into a predetermined high voltage (for example, about -60 kV) and supplies the high voltage to the needle electrode 9 via a power supply plug 18 described later. Numeral 18 is located between the small-diameter portion 4B of the nozzle main body 4 and the output side of the high-voltage generating portion 15 and is fixed in the large-diameter cylindrical portion 2B of the spray gun main body 2, and is made of a conductive material and a bottomed cylinder. A power plug is formed in the shape of an arrow. One end of the power plug 18 is connected to the high voltage generator 15 via a brush 17, and the other end of the power plug is closed via a power spring 19. 7D. Reference numeral 20 denotes an O-ring provided on the flange portion 2C of the spray gun body 2 at an outer peripheral side of the outlet 11B of the one-side paint passage 11, and the O-ring 20 is an outlet of the one-side paint passage 11. 11B and the inlet 1 of the other paint passage 12
This prevents the paint from leaking to the outside from the connection portion with 2A. Reference numerals 21 and 22 denote a one-side supply / discharge port provided on the outer peripheral side of the small-diameter portion 4B of the nozzle body 4, respectively. The one-side supply / discharge port 21 is connected to the piston 7B of the paint valve 7 and The other side supply / discharge port 22 communicates with the air chamber A between the piston 7B and the guide 7E. Then, the compressed air is supplied into the air chamber A from the one side supply / discharge port 21 and the air in the air chamber B is discharged from the other side supply / discharge port 22, so that the needle valve body 7C of the paint valve 7 is closed. Then, by supplying compressed air into the air chamber B from the other side supply / discharge port 22 and discharging air in the air chamber A from the one side supply / discharge port 21, the needle valve body 7C opens. ing. Reference numeral 23 denotes a pattern air passage or an atomization air passage formed in the spray gun main body 2 on the outer peripheral side of the high voltage generation unit 15 (hereinafter, referred to as the pattern air passage 2).
3), the inlet of the pattern air passage 23 is connected to an external compressor (not shown), and the outlet of the pattern air passage 23 is connected to each pattern air outlet 6C of the air nozzle 6 via each pattern air inlet 4E of the nozzle body 4. Is in communication with The pattern air passage 23 receives the compressed air from the compressor via an air control valve (not shown).
Are supplied to each pattern air jet port 6C. The same applies to the atomizing air passage. Reference numeral 24 denotes a mounting holder provided on the base end side of the spray gun cover 1, and the mounting holder 24 is fixed to the end cover 3 via bolts (not shown). The spray gun for painting is attached to a reciprocator (not shown) in the painting booth by the attachment holder 24. According to the present embodiment, the spiral pipe 10, the high voltage generating section 15, and the like are assembled to the spray gun main body 2, and then the spray gun main body 2 is assembled.
Nozzle body 4 with a paint nozzle 5, a paint valve 7, etc.
Are mounted while being positioned by the positioning member 13, whereby the outlet 11 </ b> B of the one-side paint passage 11 and the inlet 12 </ b> A of the other-side paint passage 12 communicate with each other. Next, the fixing ring 14 is externally fitted to the nozzle body 4 and screwed onto the tip end of the large-diameter cylindrical portion 2B of the spray gun body 2 to fix the nozzle body 4 to the spray gun body 2; A spray gun for painting is assembled by screwing and attaching to the large diameter portion 4A of the nozzle body 4. When the paint is discharged from the color changing valve device, the paint flows into the one-side paint passage 11 through the spiral pipe 10, and from the one-side paint passage 11 through the other-side paint passage 12. It is supplied into the guide cylinder 5A of the nozzle 5. Next, compressed air is supplied into the air chamber B through the other side supply / discharge port 22 and the air chamber A is supplied from the one side supply / discharge port 21.
When the air inside is discharged to the outside, the piston 7B of the paint valve 7
Moves together with the needle valve element 7C to the closing portion 7D side, whereby the needle valve element 7C is opened, and the paint in the guide cylinder 5A of the paint nozzle 5 is sprayed from the paint spray port 5C. The spraying of the paint is promoted by the atomizing air jetted from each atomizing air jet port 6B of the air nozzle 6, and the spray pattern is elliptical by the pattern air jetting from each pattern air jet port 6C. Or formed in an oval shape. The needle-shaped electrode 9 forms a corona discharge region at its tip end by a high voltage applied from the high voltage generator 15 via the brush 17, the power supply plug 18, the power supply springs 8, 19 and the like. Then, the paint sprayed by the corona discharge area is charged. As a result, the charged paint flies toward the object connected to the ground potential and is applied to the surface of the object. Thus, according to the present embodiment, the flange portions 2C and 4C are formed on the distal end side of the large diameter cylindrical portion 2B of the spray gun main body 2 and the base end side of the large diameter portion 4A of the nozzle main body 4, respectively. An outlet 11B of the one-side paint passage 11 and an inlet 12A of the other-side paint passage 12 are opened in each of the flange portions 2C and 4C, and the positioning pin 13B of the positioning member 13 is opened.
Is fitted into the fitting hole 13A, so that the outlet 11B of the one-side paint passage 11 and the inlet 12
A is positioned and communicated with each other, so that the paint in the one-side paint passage 11 can flow into the other-side paint passage 12 reliably, and the paint pool generated in the gap between the flange portions 2C and 4C. Can be significantly reduced or eliminated. As a result, the paint passages 11, 12 and the like can be easily cleaned with the cleaning solvent.
The work efficiency of the washing work can be greatly improved, and the setup time at the time of color change can be shortened to increase the efficiency of the painting work. Also, since the amount of cleaning solvent used can be reliably reduced, cleaning costs can be improved and cleaning waste liquid discharged into the painting booth can be significantly reduced, effectively preventing the deterioration of the coating environment. Can be prevented. In the above embodiment, the positioning member 13 is used.
Has described that the fitting hole 13A is provided in the flange portion 4C of the nozzle body 4 and the positioning pin 13B is fixed to the flange portion 2C of the spray gun body 2, but instead of this, the flange portion 4C of the nozzle body 4 is replaced. May be provided with a positioning pin, and a fitting hole may be provided in the flange portion 2C of the spray gun body 2. In the above embodiment, the spiral pipe 10 is used as the paint supply pipe. However, a straight pipe may be used depending on, for example, the type of the paint viscosity and electric resistance. In the above-described embodiment, the high voltage generating section 15 is provided in the cylindrical section 2A of the spray gun main body 2. However, instead of this, the cylindrical section 2 of the spray gun main body 2 is provided.
In A, only a high-voltage resistor may be provided, and a high-voltage generating unit may be provided outside. Further, in the above-described embodiment, an electrostatic spray gun for painting in which the paint is charged by the needle-shaped electrode 9 has been described as an example. However, the present invention is not limited to this, and the paint is not charged. The present invention can also be applied to a non-electrostatic spray gun for spraying. As described in detail above, according to the present invention, the one-side paint passage and the other-side paint passage are positioned by the positioning member, and the flange portion of the spray gun body and the flange portion of the nozzle body. Between the outlet of the one-side paint passage and the inlet of the other-side paint passage.The paint from the paint supply source can be connected from the paint supply pipe to the one-side paint passage and the other-side paint passage. Can be reliably supplied into the paint nozzle through the nozzle. As a result, the paint pool generated in the gaps between the flange portions can be reduced, and the paint passages and the like can be easily cleaned with the cleaning solvent. Therefore, the work efficiency of the cleaning work is improved, and the setup time for color change is reduced. Can be shortened. Further, since the amount of the washing solvent used can be reduced, the washing waste liquid discharged into the coating booth can be reduced and the deterioration of the coating environment can be effectively prevented.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view of a spray gun for painting according to an embodiment of the present invention. FIG. 2 is an enlarged longitudinal sectional view showing a main part in FIG. FIG. 3 is an external perspective view showing an enlarged view of a nozzle body and the like. [Description of Signs] 2 Spray gun body 2C Flange part 4 Nozzle body 4C Flange part 5 Paint nozzle 6 Air nozzle 7 Paint valve 7C Needle valve body 10 Spiral pipe (paint supply pipe) 11 One-side paint passage 11A Inlet 11B Outlet 12 Other side paint passage 12A Inflow port 12B Outflow port 13 Positioning member

Claims (1)

(57) [Claims] A spray gun body having a flange portion formed on the tip side,
A nozzle body provided on the distal end side of the spray gun body and having a flange portion formed on the base end side to be in contact with the flange portion of the spray gun main body; and a paint provided on the distal end side of the nozzle body and spraying paint. A nozzle, an air nozzle that is provided on the tip side of the paint nozzle and ejects atomizing air and pattern air, and is provided on the base end side of the nozzle body, and supplies and discharges compressed air to connect the needle valve body to the paint nozzle. A paint valve that opens and closes, and is provided at the tip side of the spray gun body, an outlet is opened in a flange portion of the spray gun body, and the inflow port is connected to an external paint supply source through a paint supply pipe. A paint passage provided on the nozzle body, an inflow opening opening at a flange portion of the nozzle body, and an outflow passage communicating with the inside of the paint nozzle; and the spray gun body. Is provided between the nozzle body, painting spray gun comprising consist of a positioning member that communicates by positioning the the one side paint passage and said other side paint passage.