JP2002224611A - Coating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonelectrostatic coating method, in which a high voltage generator or insulating equipment is dispensed with, the troublesome to form a conductive primer layer is eliminated and the coating efficiency of a coating material is improved. SOLUTION: The distance (L) between a bell type coater (1) and the surface of a material (4) to be coated is kept to <=100 mm, a coating pattern width (P) of the bell type coater (1) on the surface of the material (4) to be coated is narrowed down to about <=2 times of the tip diameter of the rotary atomizing head (2) by shaping air (3) and the air pressure is set to control the wind speed of the shaping air on the surface of the material (4) to be coated to <=7 m/see. As a result, the coating material particles jetted in the peripheral direction of the rotary atomizing head of the bell type coater reaches on the surface of the material to be coated by the effect of the shaping air to be directed to the direction of the material to be coated without forming an electric static field.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-electrostatic coating method which does not create an electrostatic field between a coating machine and an object to be coated.

[0002]

2. Description of the Related Art In an industrial coating line for automobiles, home appliances, etc., a negative charge is applied to paint sprayed from a coating machine, an object to be grounded is set to a plus side, and the coating object is Electrostatic coating, in which an electrostatic field is applied between the layers to perform coating, is generally employed.

[0003] Electrostatic coating is considered to be effective in resource saving and pollution control because it has a much higher coating efficiency than non-electrostatic air spray coating and airless spray coating. . In particular, electrostatic spraying is performed by a rotary atomizing bell-type coating machine that atomizes paint supplied to a high-speed rotating bell-type rotary atomizing head by centrifugal force and Coulomb force of an electrostatic field and adsorbs it on the surface of the object to be coated. The coating efficiency of the paint is higher than that of the electrostatic coating by the air atomization type or the airless atomization type coating machine, and a high quality coating film can be obtained. It is often used for painting exterior parts.

[0004]

However, in order to perform electrostatic coating, for example, a high voltage generator for applying a high voltage to a rotary atomizing head of a bell type coating machine or a coating machine to which a high voltage is applied is used. Insulation equipment and the like for electrically insulating the paint supply system that supplies the paint to the coating machine are required, so that the cost of the coating equipment is increased.

In recent years, the number of lightweight and easily molded plastic interior and exterior parts for automobiles has been increasing, and in order to electrostatically coat such plastic objects to be coated, it is necessary to use such plastic parts. The surface has to be coated with a conductive paint in advance using a non-electrostatic air spray gun or airless spray gun to form a conductive primer layer for grounding.

Accordingly, the present invention provides a non-electrostatic coating method having a high coating efficiency in order to eliminate the trouble of forming a conductive primer layer by eliminating the need for a high-voltage generator and insulation equipment. Is a technical issue.

[0007]

In order to solve the above-mentioned problems, according to the present invention, the paint supplied to a high-speed rotating bell-shaped rotary atomizing head is supplied from the tip of the rotary atomizing head. Bell-type coating which atomizes by centrifugal force and sprays in the circumferential direction of the rotary atomizing head, and at the same time directs the sprayed paint particles in the direction of the object to be coated with only shaping air jetted from around the rotary atomizing head. Non-electrostatic coating method using a machine,
The distance between the bell type coating machine and the surface of the object to be coated by the coating machine is kept at 100 mm or less, and the shaping air is used to reduce the coating pattern width of the bell type coating machine on the surface of the object to be coated. The diameter of the tip of the rotary atomizing head is reduced to approximately twice or less, and the air pressure of the shaping air is set so that the wind speed of the shaping air on the surface of the workpiece is 7 m / sec or less. .

According to the first aspect of the present invention, when the distance between the coating machine and the surface of the object to be coated is kept at 100 mm or less by bringing the bell type coating machine close to the object to be coated, the suction called the Coulomb force during that time. Even without creating an electrostatic field in which a force acts, the paint particles sprayed in the circumferential direction of the rotary atomizing head of the bell type coating machine are directed to the work object by shaping air. To the surface.

Further, if the Coulomb force of the electrostatic field does not act, the paint particles sprayed from the rotary atomizing head of the bell type coating machine diffuse at a wide angle without going straight to the surface of the object to be coated. Although the coating efficiency tends to decrease, as in the present invention, the coating pattern width of the bell type coating machine formed when the coating particles are applied to the surface of the object to be coated is adjusted by rotating the atomizing head with shaping air. If the diameter is narrowed to approximately twice or less of the tip diameter, the wide-angle diffusion of the paint particles is suppressed, the straightness to the surface of the object is secured, and the coating efficiency is significantly improved.

Further, if the air pressure of the shaping air ejected from a bell type coating machine which is close to the surface of the object to be coated is less than 100 mm, the shaping air collides with the surface of the object at a high wind speed. As a result, an overspray paint that does not adhere to the surface of the object to be coated increases due to a strong bounced air current that scatters the paint particles. If the air pressure is set so as to be 7 m / sec or less, scattering of the paint particles due to the rebound air flow is suppressed, and the amount of overspray paint is reduced.

According to the second and third aspects of the present invention, as the shaping air, a vortex flow which is jetted from the periphery of the rotary atomizing head in a vortex shape in which the jetting direction is inclined in the rotation direction or the anti-rotation direction of the rotary atomizing head. , Using one or both of the conical airflows in which the jetting direction is inclined toward the center of the rotary atomizing head and jetted in a conical shape from the periphery of the rotary atomizing head, and when both are used, the conical airflow is used. Is ejected from the outside to the inside of the vortex.

Both the vortex and the conical air flow direct the paint particles, which are sprayed in the circumferential direction by the centrifugal force of the rotary atomizing head, to the object to be coated. In particular, the vortex causes atomization of the paint and a uniform circular shape. The conical air flow contributes to the formation of the paint pattern and the narrowing of the paint pattern width. Thus, when both are used simultaneously, a circular pattern of an appropriate size can be easily formed.

Further, as in the invention of claim 4, the conical air flow is jetted toward the center side of the rotary atomizing head at an angle of 10 ° or more and 40 ° or less, so that the vortex flows in the rotation direction of the rotary atomizing head or When the jetting is performed at an angle of 10 ° or more and 60 ° or less in the anti-rotation direction, when the wind speed of the shaping air on the surface of the workpiece is set to 7 m / sec or less, the width of the coating pattern is changed to the tip diameter of the rotary atomizing head. Can be maintained at twice or less.

According to a fifth aspect of the present invention, the gap between the bell-type coating machine and the rotary atomizing head mounted on the tip of the bell-type coating machine is maintained at a positive pressure. To form a cylindrical air curtain that covers the bell-shaped coating machine toward.

According to the fifth and sixth aspects of the present invention, when the distance between the bell type coating machine and the surface of the object to be coated is reduced to 100 mm or less, the oversprayed paint particles are converted to the bell type coating machine. It is possible to prevent the coating machine from getting into the gap between the rotary atomizing head mounted on the tip of the coating machine and sticking to the coating machine or the outer peripheral surface of the coating machine.

[0016]

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a diagram showing an example of a coating method according to the present invention, FIG. 2 is a diagram showing an example of a bell type coating machine used in the method of the present invention, FIG. 3 is a schematic diagram showing streamlines of shaping air, and FIG. It is a graph which shows coating efficiency.

In the drawing, reference numeral 1 denotes a coating material supplied to a bell-shaped rotary atomizing head 2 which rotates at a high speed, is atomized from the tip of the rotary atomizing head 2 by centrifugal force, and is sprayed in the circumferential direction. ,
This is a bell-type coating machine in which the sprayed paint particles are directed toward the workpiece 4 only by the shaping air 3 which is blown out from around the rotary atomizing head 2.

The bell-type coating machine 1 can be fixed at a fixed position, or it can be fixed, or it can be mounted on a reciprocating device or a painting robot, and it can be moved while moving. Distance L from the surface of the coating 4
Is installed or the operation is controlled so that is maintained at 100 mm or less.

As a result, the coating particles sprayed in the circumferential direction of the rotary atomizing head 2 of the bell type coating machine 1 are directed by the shaping air 3 to the direction of the object 4 so that the coating particles are applied to the object. 4 can be reliably reached.

However, in the case of non-electrostatic coating in which no Coulomb force acts to suck paint particles in the direction of the object 4 between the bell-type coating machine 1 and the object 4, the bell-type coating machine 1 The paint particles which are sprayed in the circumferential direction from the rotary atomizing head 2 and directed toward the object 4 by the shaping air 3 do not go straight to the surface of the object 4 to be rotated. With the centrifugal force of 2, the light is diffused at a wide angle, and the coating efficiency of the paint tends to decrease.

That is, in the case of electrostatic coating in which an electrostatic field is created between the bell type coating machine and the object to be coated, the coating particles sprayed in the circumferential direction from the rotary atomizing head of the bell type coating machine are coated. Due to the action of shaping air that is directed to the direction of the object and the action of the electrostatic field that attracts the paint particles toward the object by Coulomb force, the paint particles are caused to travel straight against the surface of the object. There is little overspray paint that escapes without being applied to the surface, but in non-electrostatic coating, the Coulomb force that attracts paint particles in the direction of the workpiece does not work, so the paint particles inevitably have a wide angle. And spread over paint.

Therefore, the coating pattern width P of the bell type coating machine 1 on the surface of the workpiece 4 is narrowed by the shaping air 3 to approximately twice or less the tip diameter of the rotary atomizing head 2.
At the same time as suppressing the wide-angle diffusion of the paint particles, the paint particles are given a straightness to the surface of the article 4 to be applied, thereby increasing the paint application efficiency.

The narrowing of the coating pattern width P by the shaping air 3 is performed by, for example, tilting the jetting direction of the shaping air 3 from the direction perpendicular to the surface of the workpiece 4 toward the center of the rotary atomizing head 2, Alternatively, it is performed by tilting the rotary atomizing head 2 in the rotation direction or the counter rotation direction.

However, if the shaping air 3 is too strong, the paint particles are scattered by the rebounding airflow 5 generated when the shaping air 3 collides with the surface of the object 4 to be coated.
The amount of overspray paint not applied to the surface of the article 4 to be coated increases, and the coating efficiency of the paint may be rather lowered.

An experiment was conducted to measure the coating rate of the paint by changing the air pressure of the shaping air 3 in various ways. When the wind speed of the shaping air 3 on the surface of the workpiece 4 was 7 m / sec or less, It was found that the effect of improving the coating rate by the shaping air 3 was better than the reduction in the coating rate by the rebound airflow 5. Therefore, the air pressure of the shaping air 3 is set so that the wind speed of the shaping air 3 on the surface of the coating material 4 is 7 m / sec or less.

The embodiment of the present invention has been described above. Next, an optimal embodiment will be described more specifically with reference to FIGS. As shown in FIG. 2, the bell type coating machine 1 used in this example has a rotary atomizing head 2 having a diameter of 50 mm attached to a tip of a tubular rotary shaft 7 of an air motor 6 driven to rotate at a high speed. A paint nozzle 8 for supplying paint to the rotary atomizing head 2 is inserted therein, and a manifold 10 to which a plurality of paint supply hoses and cleaning fluid hoses 9 are connected is provided on the rear end side of the paint nozzle 8. It is installed. The manifold 10 is provided with small-diameter nozzles (not shown) that are individually connected to the hoses 9... And these are inserted and disposed in the paint nozzle 8 in a bundled state. Each of the color paints and the cleaning fluid can be individually supplied to the head 2.

An annular shaping air jetting housing H for jetting out shaping air 3 is formed at the tip end side of the bell type coating machine 1. A large number of eddy flow forming holes 11A having a diameter of about 0.5 to 1 mm are formed in the housing H in such a manner that the eddy direction is inclined in the rotation direction or the anti-rotation direction of the rotary atomizing head 2 and the eddy flow 3A is ejected. At the same time, the ejection direction is tilted toward the center of the rotary atomizing head 2 and the vortex 3A
A large number of conical air flow forming holes 11B having a diameter of about 0.5 to 1 mm for ejecting a conical air flow 3B in a conical shape from the outside toward the inside are formed in an annular shape, and the vortex flow 3A and the conical air flow are formed. 3B acts as shaping air 3.

That is, the vortex 3A acts to direct the paint particles, which are sprayed in the circumferential direction by the centrifugal force of the rotary atomizing head 2, toward the object 4, and at the same time, increases the width of the paint pattern to some extent. Has a function of adjusting the shape to a uniform circular shape, and is formed near the edge of the rotary atomizing head 2, which contributes to atomization of the paint.

The vortex flow forming holes 11A are provided with a predetermined twist angle ω (50) in the rotation direction or the anti-rotation direction with respect to a straight line V lowered on the object 4 in parallel with the rotation axis X of the rotary atomizing head 2. (Degrees) and a predetermined angle (approximately 10 degrees) inward and spirally formed. The air supply pressure to the vortex flow forming hole 11A is 0 to 0.4 MPa.
a. Injecting the swirl 3A in the anti-rotational direction is more excellent in atomization of the paint and the circularity and uniformity of the coating pattern than in forming the swirl flow forming holes 11A in the rotation direction.

Since the conical air flow 3B is an air flow directed from the outside to the inside of the vortex flow 3A, the paint particles ejected in the circumferential direction by the centrifugal force of the rotary atomizing head 2 are directed to the object 4 to be coated. At the same time, it has an action of narrowing the coating pattern width P. In this example, the inclination angle θ of the conical air flow forming hole 11B is 20 °, and the air supply pressure to the conical air flow forming hole 11B is about 0 to 0.5 MPa.

As described above, since the vortex flow 3A and the conical air flow 3B can be used as the shaping air 3, these can be selectively used according to the coating conditions. For example, when it is not necessary to make the coating pattern width P so small and it is desired to form a uniform circular coating pattern, the vortex 3A
Only shaping air 3 may be used, and
When it is necessary to maintain a uniform circular coating pattern and narrow down the diameter, both the conical air flow 3B and the vortex flow 3A may be used as the shaping air 3, and the width of the coating pattern is narrowed down even if the uniformity is somewhat lost. If necessary, only the conical air flow 3B may be used as the shaping air 3.

Reference numeral 12 denotes an air jet to a space S generated between the shaping air jetting housing H and the rotary atomizing head 2 mounted inside the housing H to make the inside of the space S a positive pressure state. This is a pollution prevention air jet. Reference numeral 13 denotes an air curtain forming hole that forms a substantially cylindrical air curtain so as to cover the bell type coating machine 1 to prevent paint particles from adhering to the tip of the shaping air ejection housing H.

The operation and experimental results when coating is performed by the method of the present invention using the bell type coating machine 1 will be described. The rotary atomizing head 2 is rotated at 10,000 to 20,000 rpm, and 0.03 to 0.05 MPa is supplied to the vortex forming hole 11A.
Air is supplied to the conical air flow forming hole 11B at a pressure of 0 to 0.3 MPa, and paint of any color is
When discharged at 20 to 150 cc / min, the paint is atomized by the centrifugal force of the rotary atomizing head 2 and is sprayed in the circumferential direction of the rotary atomizing head 2.

As shown in FIG. 3, the paint particles are forcibly directed to the object 4 by the effect of the shaping air 3 composed of the conical air flow 3B and the vortex 3A, and are applied to the surface of the object 4. Is done. When the coating was performed while changing the coating conditions by moving the distance L between the bell-type coating machine 1 and the surface of the work 4 in the range of 30 mm to 100 mm, the bell-type coating machine 1
When the coating pattern width P is narrowed down to approximately twice the tip diameter of the rotary atomizing head 2 and the wind speed of the shaping air 3 on the surface of the workpiece 4 is 3 to 7 m / sec, The fine particles were finely divided, and a coating film having excellent coating quality was obtained, and the coating efficiency was excellent. At this time, the paint particles sprayed from the rotary atomizing head 2 and applied to the surface of the object 4 are atomized to an average particle size of about 35 μm, and the application efficiency is very high, 65 to 90%. The coating efficiency was high, and was about the same as the case where electrostatic coating was performed so that equivalent coating quality could be obtained for automotive parts on an actual line.

When the rotary atomizing head 2 is rotated at a high speed,
Due to the centrifugal force, an air flow flowing out of a space S formed between the shaping air jetting housing H formed at the tip of the bell type coating machine 1 and the rotary atomizing head 2 mounted inside the housing H is formed. Along with this, a negative pressure is generated in the space S, and an air flow flowing into the space S along the housing H is formed, so that the paint particles atomized by the rotary atomizing head 2 are added to the air flow. There is a possibility that the vehicle may get inside and enter the inside of the coating machine 1 and adhere thereto. For this reason, at the time of painting, air is blown out from the shaping air blow-out housing H into the space S to make the space S a positive pressure state, thereby preventing paint particles from entering.

Further, when the conical air flow 3B is vigorously jetted from the conical air flow forming hole 11B formed in the shaping air jetting housing H, the paint floating near the rotary atomizing head 2 together with the air around the coating machine 1 If the particles are entrained and adhere to the tip of the housing H and left unattended, the paint adhering to the tip may fall onto the object 4 to be coated and cause poor coating such as dust.

Here, when a substantially cylindrical air curtain is blown out from the air curtain forming hole 13 so as to cover the coating machine 1, the paint particles floating around the coating machine 1 are wound around the air curtain together with the surrounding air. Air curtain forming port 1
Even if the paint particles adhere to the outer peripheral surface of the coating machine 1 near 3 and become dirty, it is possible to prevent the paint particles from adhering to the front end of the housing H, so that poor coating hardly occurs.

FIGS. 4A and 4B are graphs showing the coating efficiency when the torsional angle ω of the vortex 3A is 50 ° and 60 °, respectively. The coating conditions include the distance L and the conical air flow. 3B
Except for changing the supply pressure, the supply pressure of the vortex 3A is 0.03 MPa, and the number of revolutions of the rotary atomizing head 2 is 15000 r.
pm, the discharge rate was 150 cc / min, and the relative linear movement speed between the bell type coating machine 1 and the object 4 was 800 mm / sec.

4 (a) and 4 (b), it can be seen that, as long as the other coating conditions are the same, the smaller the twist angle ω, the better the coating efficiency. However, when the twist angle ω is set to 0 °, the effect of the vortex flow 3A is lost, and only the conical air flow 3B is effective as the shaping air 3, so that the paint pattern width P tends to be smaller.

Further, from each example of FIGS. 4A and 4B,
It can be seen that when the supply pressure of the conical air flow 3B and other coating conditions are equal, the shorter the distance L, the better the coating efficiency. However, if the distance L is reduced and the bell-type coating machine 1 is brought too close to the object 4, the solvent in the coating particles is applied to the object 4 before the solvent is sufficiently volatilized, or is applied per unit area. Since there is a problem that the coating amount to be applied becomes too large and coating defects such as sagging tend to occur, an appropriate distance L for stably forming a uniform circular coating pattern can be obtained.
Is 30 mm or more.

Further, regardless of the magnitude of the twist angle ω, the coating efficiency is highest when the supply pressure of the conical air flow 3B is 0.1 MPa, the twist angle ω of the vortex flow 3A = 50 °, and the distance L = 7.
At 0 mm, the wind speed of the shaping air 3 formed by the vortex 3A and the conical airflow 3B was about 5 m / sec. In each case, the coating efficiency was 65 to 90%, and the coating efficiency was almost the same as that in the case where electrostatic coating was performed so that the same coating quality could be obtained for automobile parts on an actual line.

Further, in the present invention, since the coating pattern width P is set to 100 mm or less, which is much smaller than that of ordinary electrostatic coating or the like, the coating amount is reduced with the discharge amount of the coating material. If the discharge amount is small, the same degree of atomization can be obtained even if the rotational speed of the rotary atomizing head 2 is reduced. For this reason, it is possible not only to reduce the mechanical consumption and the air consumption of the rotating part, but also to reduce the number of rotations, thereby suppressing the scattering of the paint particles and acting to improve the coating efficiency. The inventor performed a control experiment by changing only the rotation speed of the rotary atomizing head 2 and compared the coating efficiencies. As a result, the coating efficiency at a rotation speed of 15,000 rpm was compared with the coating efficiency of 65% at a rotation speed of 25,000 rpm. 7 wearing efficiency
5%.

The vortex 3A serving as the shaping air 3
The coating conditions such as the torsion angle ω and the incline angle θ of the conical air flow 3B, the supply pressure thereof, the amount of paint discharged, the tip diameter of the rotary atomizing head and the number of rotations are not limited to those described above, and a bell type coating machine is used. 1
When the distance L between the object and the surface of the object 4 is kept at 100 mm or less, the object
The width P of the coating pattern of the bell type coating machine 1 on the surface of the workpiece 1 can be narrowed to approximately twice or less the diameter of the tip of the rotary atomizing head 2, and the wind speed of the shaping air 3 on the surface of the workpiece 4 is 7 m / s. It suffices if the following conditions are satisfied. For example, if the above-described conditions are satisfied, the shaping air 3 is not the vortex flow 3A or the conical air flow 3B, but the air flow that is jetted cylindrically from around the rotary atomizing head 2 toward the surface of the object 4 to be coated. May be used.

[0044]

As described above, according to the method of the present invention, the paint sprayed in the circumferential direction of the rotary atomizing head of the bell painter by shaping air by bringing the bell painter close to the object to be coated. By directing the particles in the direction of the object to be coated and applying a coating pattern that is less than twice the tip system of the rotary atomizing head, the coating particles can be applied with high coating efficiency without creating an electrostatic field. Since it can be applied to the surface, a high pressure generator and insulating equipment are not required, and a very excellent effect that the trouble of forming the conductive primer layer can be eliminated can be achieved.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a coating method according to the present invention.

FIG. 2 is a view showing an example of a bell type coating machine used in the method of the present invention.

FIG. 3 is a schematic diagram showing a relationship between shaping air and a coating pattern.

FIG. 4 is a graph showing coating efficiency.

[Explanation of symbols]

 1 ... Bell type coating machine 2 ... Rotary atomizing head 3 ... Shaping air 3A ... Swirl 3B ... Conical air flow 4 ... Coating object L ... Distance P ... Coating pattern Width 6 Air motor 7 Tubular rotary shaft 8 Paint nozzle 9 Paint supply hose 10 Color changing device 11A Swirl flow forming hole 11B Conical air flow forming hole H … Housing for ejecting shaping air S ……… Space

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tomoaki Naruse 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Co., Ltd. (72) Inventor Yasushi Yasushi 1-9-9 Kakimotocho Toyota City, Aichi Prefecture Trinity Within Industrial Co., Ltd. (72) Inventor Makoto Ichimura 1-9-9 Kakimotocho, Toyota-shi, Aichi F-term within Trinity Industrial Co., Ltd. 4D075 AA08 AA23 AA84 AA85 CA47 DC12 DC13 DC18 4F033 AA01 BA03 CA01 DA01 EA01 LA02 PA11 PB16 PD06

Claims (6)

[Claims] 1. The method of claim 1, wherein the paint supplied to the high-speed rotating bell-shaped rotary atomizing head is atomized from the tip of the rotary atomizing head by centrifugal force and sprayed in the circumferential direction of the rotary atomizing head. A non-electrostatic coating method using a bell-type coating machine in which the sprayed paint particles are directed toward an object to be coated only by shaping air ejected from around the rotary atomizing head, wherein the bell-type coating machine is used. The distance (L) between (1) and the surface of the object (4) to be coated by the coating machine is kept at 100 mm or less, and the shaping air (3) is used to adjust the distance (L) on the surface of the object (4). The coating pattern width (P) of the bell type coating machine (1) is narrowed down to approximately twice or less the tip diameter of the rotary atomizing head (2), and the shaping air (3) on the surface of the workpiece (4) is reduced. ) So that the wind speed of the shaping air (3) is 7 m / s or less. Coating method characterized by setting the air pressure. 2. A vortex as the shaping air (3), the jetting direction of which is inclined in the direction of rotation of the rotary atomizing head (2) or in the counter-rotating direction, and is vortexly jetted from around the rotary atomizing head (2). (3A) and one of the conical air flow (3B) in which the ejection direction is inclined toward the center of the rotary atomizing head (2) and is ejected in a conical shape from the periphery of the rotary atomizing head (2). The coating method according to claim 1, which is used. 3. A vortex which is jetted from the periphery of the rotary atomizing head (2) as the shaping air (3) in a direction in which the jetting direction is inclined in the rotational direction or the anti-rotational direction of the rotary atomizing head (2). (3A) and a conical air flow (3B) that is ejected in a conical shape from the outside to the inside of the vortex (3A) with the ejection direction inclined toward the center of the rotary atomizing head (2). The coating method according to claim 1. 4. The conical air stream (3B) is rotated and atomized by inclining the conical air stream (3B) at an angle of 10 ° or more and 60 ° or less in the rotation direction or the anti-rotation direction of the rotary atomization head (2). The coating method according to claim 2 or 3, wherein the head (2) is ejected toward the center side at an angle of 10 ° or more and 40 ° or less. 5. The method of coating with the bell type coating machine (1),
Air is blown into the space (S) generated between the annular shaping air blowing housing (H) formed at the tip and the rotary atomizing head (2) attached inside the housing (H), and the inside of the space (S) is blown. The coating method according to any one of claims 1 to 4, wherein the pressure is set to a positive pressure. 6. The method of coating with the bell type coating machine (1),
The coating method according to any one of claims 1 to 5, wherein a substantially cylindrical air curtain is formed to cover the bell-shaped coating machine (1) from a rear side toward a tip side.