JP3405492B2 - Paint spray gun - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating spray gun used for coating an object to be coated such as an automobile body.

[0002]

2. Description of the Related Art For example, when painting an automobile body, paint is supplied to the inner peripheral surface of a rotating cup-shaped atomizing head, which is atomized by centrifugal force and atomized from the peripheral edge of the tip of the atomizing head. Widely used is rotary atomization electrostatic coating (minibell), which releases the applied paint and causes the paint to fly to the surface of the object by the high voltage applied between the object and the cup-shaped atomizing head. ing.

Such rotary atomizing electrostatic coating (mini bell)
Generally has higher paint application efficiency than air atomized electrostatic coating or airless atomized coating.

Recently, Japanese Patent Laid-Open No. 3-101
As described in Japanese Patent No. 858, Japanese Patent Application Laid-Open No. 6-114327, etc., it is possible to use the above minibell even when using a so-called metallic paint containing a flake pigment such as aluminum or mica. , Minibells have begun to be used in all processes of atomization coating processes (intermediate coating, topcoat basecoat, topcoat clearcoat) for automobile bodies.

[0005]

However, in the above minibell, as shown in FIG. 6 (a), a cup-shaped atomizing head 51 (hereinafter referred to as a cup) is rotated,
Since the paint T is atomized while being scattered in the radial direction of the cup 51 by its centrifugal force, as shown in FIG. 6B, the shaping air S is directed from the cup 51 side toward the object to be coated side. It is necessary to forcibly change the scattering direction of the coating material by discharging the paint to form an air layer.

Therefore, as shown in FIG. 6 (c), the spray flow R is disturbed to reduce the coating efficiency of the paint T, and
Since the paint particles T ₁ which cannot be controlled by the shaping air S are scattered in the radial direction of the cup 51, there is a problem that the coating efficiency is also reduced.

On the other hand, as shown in FIG. 7 (a), the coating thickness distribution of the paint sprayed by the mini bell on the coating surface is a donut shape in which the thickness of the central portion is thin and the thickness of the outer peripheral portion is large. Therefore, in order to prevent this, it is necessary to reciprocate the spray gun equipped with the mini bell, and as a result, the coating efficiency of the paint is further deteriorated and the coating device is used. There is also a problem that it becomes expensive, and it has been a problem to solve these problems.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and when applying electrostatic atomization coating to an object to be coated, the efficiency of application of the atomized paint is high and It is an object of the present invention to provide a coating spray gun that enables coating with less uneven film thickness.

[0009]

According to a first aspect of the present invention, there is provided a paint spray gun in which paint outlets arranged in a straight line are formed and the paint is supplied from the outside to communicate with the paint outlets. An atomizing head having a mouth and a continuous rectangular outlet shape surrounding the outer periphery of the paint outlet arranged in a straight line of the atomizing head, and the rectangular outlets are opposed to each other. Two sides are configured to have an air nozzle that blows a parallel air flow to the atomized paint that is linearly arranged.
The coating spray gun according to claim 2 is an atomizing head having a paint outlet that is linearly arranged and a paint supply port that communicates with the paint outlet and supplies paint from the outside.
It has a rectangular outlet shape surrounding the outer periphery of the paint outlet of the atomizing head, and surrounds the paint particles atomized by the atomizing head and exiting from the paint outlet, and conveys them to the object to be coated. An air nozzle that blows an air flow is provided, and the air blown from the air nozzle has a low pressure and a large air volume as claimed in claim 3, and the pressure of the air blown from the air nozzle is 0.1 to 0.5 kgf / cm as claimed in claim 4. ² and the amount of air is ² L / min or more, claim 5 has an ultrasonic vibrator for high-frequency vibration of the atomizing head, and claim 6 has an atomizing head and an ultrasonic vibrator. And a structure in which an insulator is provided between the atomization heads, and the atomization head also serves as a contact charging electrode.
The atomizing head is provided with a plurality of paint supply ports, and each of the paint supply ports is in communication with one or two or more divided paint outlets. I am trying.

[0010]

In the coating spray gun according to the first aspect of the present invention, the paint outlets linearly arranged are formed, and the paint supply port communicating with the paint outlets for supplying the paint from the outside is formed. The atomization head atomizes the paint supplied from the paint supply port, and the atomized paint is blown out from the paint outlets arranged in a straight line. The painting pattern does not have a donut shape.

Further, it has a continuous rectangular outlet shape surrounding the outer periphery of the paint outlets arranged in a straight line of the atomizing head, and the two opposite sides of the rectangular outlet are linear. With respect to the arrayed atomized paint, by adopting a configuration including an air nozzle that blows out a parallel air flow, even if the paint outlets are linearly arranged, the paint atomized by the parallel air flow The pattern width of the required coating pattern is ensured by being transported to the surface to be coated, and further, air is not sprayed to promote atomization of the paint, and a parallel air flow is used only for transporting the paint. It becomes easy to set the optimum air flow for the coating efficiency.

With the coating spray gun according to the third aspect of the present invention, the air blown out from the air nozzle has a low pressure because of the above-mentioned structure, and therefore the parallel air flow is disturbed when the atomized paint is conveyed. As a result, the atomized paint particles are prevented from scattering, and since the air blown from the air nozzle has a large air volume, the atomized paint particles reliably fly toward the object to be coated. It will be.

In the coating spray gun according to the fourth aspect of the present invention, the pressure of the air blown from the air nozzle is 0.1 kgf.
If it is less than / cm ² , the atomized paint tends not to be sufficiently conveyed toward the object to be coated, and the pressure is 0.5 kg.
If it is greater than f / cm ² , the parallel air flow tends to be turbulent, and if the air flow rate is less than 2 L / min, the coating particles tend to fly toward the object to be coated. By so doing, the turbulence of the parallel air flow is reliably suppressed, and the paint particles are conveyed toward the object to be coated.

With the coating spray gun according to the fifth aspect of the present invention, the atomizing head is vibrated at high frequency by the ultrasonic vibrator by the above configuration, and the supplied paint is atomized more efficiently. To be done. That is, the atomizing head functions as an ultrasonic horn for atomizing the paint.

The coating spray gun according to the sixth aspect of the present invention has a structure in which an insulator is provided between the atomizing head and the ultrasonic vibrator, so that, for example, if an insulator such as ceramics is used. Therefore, the leakage of the current flowing to the ultrasonic transducer side when a high voltage is applied to the atomizing head is prevented.

In the coating spray gun according to claim 7 of the present invention, by applying a high voltage to the atomizing head as an electrode for contact charging to charge the paint by contact, the charging efficiency becomes good, and the coating efficiency is improved. The wearing efficiency is further improved.

According to an eighth aspect of the present invention, a coating spray gun is provided with a plurality of paint supply ports on the atomizing head, and each paint supply port communicates with one or two or more paint outlets. With this configuration, for example, if the paint is not supplied from all of the paint supply ports divided into a plurality of parts, but is supplied from only a part of them, the fog is generated only from the paint outlet communicating with the paint supply port. The sprayed paint is sprayed, and as a result, the coating pattern width becomes variable and wasteful paint consumption can be achieved by selecting the paint supply port that supplies paint appropriately according to the coating conditions. Will be prevented.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory view showing an embodiment of a coating spray gun according to the present invention, FIG. 1 (a) is a side view, FIG. 1 (b) is a front view and FIG. 1 (c). ) Is a perspective explanatory view.

Here, the spray gun 1 is provided with an atomizing head 2 and an air nozzle 8, but the atomizing head 2
As shown in FIG. 2, a paint outlet 3 arranged in a straight line is formed, and a paint supply port 4 communicating with the paint outlet 3 for supplying paint from the outside is formed. Note that FIG.
Shows parts other than the air nozzle 8 of the spray gun 1 shown in FIG.

The paint outlet 3 is formed by providing a plurality of slits in the rectangular outlet.
The paint outlet 3 may be formed of a plurality of holes as shown in FIG.

Further, an ultrasonic vibrator 6 for vibrating the atomizing head 2 at a high frequency through an insulator 5 is provided at the rear part of the atomizing head 2, and the atomizing head 2 is for contact charging. The high voltage generator 7 shown in FIG. 2 also serves as an electrode.
This makes it possible to apply a high voltage to the object to be coated.

On the other hand, the air nozzle 8 surrounds the outer periphery of the paint outlet 3 of the atomizing head 2 formed between the outer plate 8c and the inner plate 8d of the air nozzle 8 as shown in FIG. 1 (b). It has a rectangular air outlet 8a, and FIG.
As shown in FIG. 3, if the air A is supplied from the air supply port 8b, the parallel air flow A ₁ can be blown out from the air outlets 8a on the upper, lower, left and right sides of the air nozzle 8.
The air outlet 8a may be formed by a plurality of slits or a plurality of holes, for example.

A coating spray gun 1 constructed in this way
At, the paint is supplied from the paint supply port 4, and the atomizing head 2 is vibrated at a high frequency by the ultrasonic vibrator 6 while the paint is being supplied. The vibration by the ultrasonic transducer 6 is, for example,
It can be set to 20 to 40 kHz.

By the high frequency vibration of the atomizing head 2,
The paint supplied to the atomizing head 2 is atomized. That is, the atomizing head 2 functions as an ultrasonic horn for atomizing the paint.

Here, the high voltage generator 7 applies a high voltage to the object to be coated. In this case, the potential of the object to be coated is 0 V, and the potential of the atomizing head 2 is, for example, −50 to −70.
It can be kV.

Generally, the conventional solvent-type electrostatic coating machine has a corona charging type (external charging type) and an induction charging type (contact charging type).
According to the corona charging method, it is possible to electrostatically coat a so-called metallic paint in which aluminum powder is mixed in the paint, but in that case the amount of charge obtained is not large enough. You can not expect a great electrostatic effect. On the other hand, when a solid color paint is electrostatically coated by using the contact charging method, a larger amount of charge and higher coating efficiency can be achieved as compared with the case of using the corona charging method.

Therefore, in the present invention, by applying a high voltage by the high voltage generator 7 to the atomizing head 2 as an electrode for contact charging, the atomized paint has a larger charge amount. It is possible to improve the coating efficiency.

Since the insulator 5 made of ceramics or the like is provided between the atomizing head 2 and the ultrasonic vibrator 6,
It is possible to prevent the current flowing when a high voltage is applied to the atomizing head 2 from leaking to the ultrasonic transducer 6 side.

The paint atomized by the atomizing head 2 in this way can be supplied, for example, by supplying a low-pressure large air volume A from the air supply port 8b using an air turbine (not shown).
The parallel air flow A ₁ is blown out, and the paint atomized and charged in the atomizing head 2 is conveyed to the coating surface by the parallel air flow A ₁ .

In this embodiment, the air A is supplied, for example, at a pressure of 0.1 to 0.5 kg / cm ² and an air flow of 800 to 6.
000 L / min.

As a result, as shown in FIG. 4A, the atomized and charged paint particles G are conveyed to the coating surface W in the direction shown in the figure, and the shaded portions are atomized and charged. It becomes the existence area of the paint particles G, and the paint particles G
Since the existing area is surrounded by the parallel air flow A ₁ blown out from the air nozzle 8, the width P as shown in FIG.
Since the coating pattern P of w can be obtained, and the air blown from the air nozzle 8 has a low pressure, the turbulence of the parallel air flow A ₁ is reduced when the atomized paint is conveyed, and the fog is reduced. The atomized paint particles are prevented from scattering, and since the air blown out has a large air volume, the atomized paint particles are reliably blown toward the object to be coated.

On the other hand, FIG. 4 (b) is an explanatory view showing how the conventional coating spray gun 11 is used for coating. In the conventional coating spray gun 11, FIG.
In order to obtain the coating pattern P having the width Pw as shown in (c), it is possible to open the spray paint spraying direction to the outside. As shown in the figure, the paint particles G have velocity components in the direction V ₁ toward the coating surface W and in the direction V ₂ parallel to the coating surface W, and thus scatter to the outside before reaching the coating surface W. There is also a large amount of paint, which reduces the coating efficiency.

However, according to the coating spray gun 1 shown in FIG. 4A, the velocity component of the paint particles G is
Since it is only toward the direction, the number of paint particles G that scatter is significantly reduced compared to the conventional coating spray gun 11,
As a result, it is possible to greatly improve the coating efficiency, and furthermore, unlike the case of coating using a conventional mini bell, the coating pattern does not become a donut shape and the coating film thickness is not uneven. .

Next, FIG. 5 shows another embodiment of the atomizing head used in the coating spray gun according to the present invention.
According to the coating spray gun 1 in the above-described embodiments, the width Pw of the coating pattern P is substantially the same as the total length of the linearly arranged paint outlets 3 in the arrangement direction, and the width Pw is fixed. It has been done.

However, in an actual painting site, there are cases where it is necessary to change the width Pw of the painting pattern P or where it is not necessary to blow out the paint from all the paint outlets 3.

Therefore, as shown in FIG. 5, the paint supply port 4 for supplying the paint to the paint outlet 3 of the atomizing head 2 is, for example,
4a, 4b and 4c, and the paint supply port 4
It is assumed that a, 4b and 4c communicate with each of the three paint outlets 3a, 3b and 3c.

Then, for example, when the paint is supplied only from the paint supply port 4b, the atomized and charged paint is
Since it is blown out only from the paint outlet 3b, the pattern width corresponding to the width H ₁ as shown in the figure can be obtained.

Further, the paint is supplied through the paint supply ports 4a and 4b.
And 4c, the atomized and charged paint is blown out from the paint outlets 3a, 3b and 3c, and a pattern width corresponding to the width H ₂ as shown in the figure is obtained. Become.

Therefore, the width Pw of the coating pattern P can be made variable by selecting the paint supply from the paint supply ports 4a, 4b and 4c according to the situation. When coating the objects to be coated successively conveyed to the
Paint is blown from the paint outlet 3a, and then paint is fed to the paint supply ports 4a and 4b to blow paint from the paint outlets 3a and 3b. On the contrary, at the end stage of (1), the number of paint outlets for spraying paint is reduced to prevent wasteful consumption of paint.

[0041]

As described above, according to the coating spray gun according to the first aspect of the present invention, the paint outlets linearly arranged are formed and communicate with the paint outlet from the outside. The paint supplied from the paint supply port is atomized by the atomizing head having the paint supply port for supplying the atomized paint, and the atomized paint is blown out from the paint outlets arranged in a straight line. Therefore, it is possible to obtain an excellent effect that a good coated surface can be obtained without the donut-shaped coating pattern as in the conventional minibell.

Further, the atomizing head has a continuous rectangular outlet shape surrounding the outer periphery of the paint outlet arranged in a straight line, and the two opposite sides of the rectangular outlet are linear. With respect to the arrayed atomized paint, by adopting a configuration including an air nozzle that blows out a parallel air flow, even if the paint outlets are linearly arranged, the paint atomized by the parallel air flow The pattern width of the required coating pattern is ensured by being transported to the surface to be coated, and furthermore, it does not accelerate the atomization of the paint by spraying air, and the parallel air flow is used only for the transport of the paint. The excellent effect that the optimum air flow can be easily set for the coating efficiency is brought about.

According to the third aspect of the present invention,
Since the pressure of the air blown from the air outlet is low, it is possible to suppress the disturbance of the parallel air flow when transporting atomized paint, and it is possible to prevent the atomized paint particles from scattering. In addition, since the air blown from the air outlet has a large air volume, there is an excellent effect that the atomized paint particles can be surely flown toward the object to be coated.

With the configuration according to claim 4 of the present invention,
The excellent effect that the turbulence of the parallel air flow can be surely suppressed and the paint particles can be conveyed toward the object to be coated is provided.

According to the fifth aspect of the present invention,
The atomizing head is vibrated at high frequency by the ultrasonic transducer,
The effect is that the supplied paint can be atomized.

According to the sixth aspect of the present invention,
Since an insulator is provided between the atomizing head and the ultrasonic transducer, if an insulator such as ceramics is used, ultrasonic vibration of the current that flows when a high voltage is applied to the atomizing head is achieved. An excellent effect that leakage to the child side can be prevented is brought about.

According to claim 7 of the present invention,
By applying a high voltage to the atomizing head as an electrode for contact charging to contact-charge the paint, it is possible to improve the charging efficiency and further improve the coating efficiency. Excellent effect is brought about.

A coating spray gun according to an eighth aspect of the present invention is provided with a plurality of paint supply ports on the atomizing head, and each paint supply port communicates with one or more paint outlets. With this configuration, for example, if the paint is not supplied from all of the paint supply ports divided into a plurality of parts, but is supplied from only a part of them, the fog is generated only from the paint outlet communicating with the paint supply port. The sprayed paint will be sprayed, and as a result, the coating pattern width can be made variable, and it will be useless if the paint supply port that supplies paint appropriately according to the coating conditions etc. is selected. The excellent effect that the consumption of the paint can be prevented is brought about.

[Brief description of drawings]

FIG. 1 is a side explanatory view (FIG. 1 (a)) and a front explanatory view (FIG. 1) showing an embodiment of a coating spray gun according to the present invention.
(B)) and a perspective explanatory view (FIG. 1 (c)).

2 is a perspective explanatory view showing an atomizing head used in the coating spray gun of FIG. 1. FIG.

FIG. 3 is a perspective explanatory view showing another embodiment of the atomizing head used in the coating spray gun according to the present invention.

FIG. 4 is an explanatory view showing a coating pattern when coating is performed using the coating spray gun according to the present invention (FIG. 4A) and an explanation showing a coating pattern when coating is performed using a conventional spray gun. It is explanatory drawing (FIG.4 (c)) which shows drawing (FIG.4 (b)) and the coating width Pw at the time of coating using the coating spray gun which concerns on this invention.

FIG. 5 is a perspective explanatory view showing still another embodiment of the atomizing head used in the coating spray gun according to the present invention.

FIG. 6 is an explanatory view showing a state of atomization and conveyance of paint by a conventional mini bell.

FIG. 7 is an explanatory diagram showing an example of the film thickness and shape of the coating pattern when coating is performed using a mini bell.

[Explanation of symbols]

1 painting spray gun 2 Atomizing head (electrode for contact charging) 3 paint outlet 4 Paint supply port 5 insulator 6 Ultrasonic transducer 7 High voltage generator 8 air nozzles 8a Air outlet 8b Air supply port 8c outer plate 8d inner plate A air A1 parallel air flow P painting pattern Pw Paint pattern width

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-5-104037 (JP, A) JP-A-6-47318 (JP, A) JP-A-4-265172 (JP, A) Actual development Sho-60- 193252 (JP, U) Actually open 53-31058 (JP, U) Actually open 53-117570 (JP, U) Special table 6-506143 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B05B 5/00-5/16

Claims (8)

(57) [Claims] 1. An atomizing head having a paint outlet arranged linearly and having a paint supply port communicating with the paint outlet for supplying paint from the outside, and a linear shape of the atomizing head. 2 has a continuous rectangular outlet shape surrounding the outer periphery of the paint outlet arranged in two, and the rectangular outlets face each other.
A coating spray gun characterized by having an air nozzle that blows a parallel air flow to the atomized paint whose sides are arranged in a straight line. 2. An atomizing head having a paint outlet arranged linearly and having a paint supply port communicating with the paint outlet for supplying paint from the outside, and a paint sprayer of the atomizing head. An air nozzle is provided which has a rectangular air outlet shape surrounding the outer circumference of the outlet, surrounds the paint particles atomized by the atomizing head and comes out of the paint outlet, and blows out a parallel air flow to be conveyed to the object to be coated. A painting spray gun characterized by that. 3. The coating spray gun according to claim 1, wherein the air blown from the air nozzle has a large amount of low pressure air. 4. The coating spray gun according to claim 3, wherein the pressure of the air blown from the air nozzle is 0.1 to 0.5 kgf / cm ² and the air volume is ² L / min or more. 5. The coating spray gun according to claim 1, further comprising an ultrasonic vibrator that vibrates the atomizing head at a high frequency. 6. The coating spray gun according to claim 5, further comprising an insulator between the atomizing head and the ultrasonic transducer. 7. The coating spray gun according to claim 1, wherein the atomizing head also serves as an electrode for contact charging. 8. The atomizing head is provided with a plurality of paint supply ports, and each paint supply port communicates with one or two or more paint outlets. The coating spray gun according to any one of 1.