JP3223032B2 - Electrostatic coating machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a center feed type electrostatic type in which paint supplied to a rotary atomizing head from a paint pipe inserted through a tubular rotary shaft of an air motor is atomized by the rotary atomizing head for coating. The present invention relates to a coating machine, and particularly to an electrostatic coating machine suitable for electrostatically coating a metallic paint.

[0002]

2. Description of the Related Art A rotating atomizing head to which a high voltage is applied is rotated at a high speed to atomize the paint by its rotating force and electrostatic force, and at the same time, paint is electrostatically applied to a work applied to the opposite pole. Electrostatic coatings that are made to be applied not only have high coating efficiency and low waste of paint, but also can form a uniform coating film. It is used for painting.

[0003] As a rotary atomizing type electrostatic coating device,
A side feed type in which the paint pipe that supplies paint to the rotary atomizing head is disposed at a position eccentric from the rotation axis of the rotary atomizing head, and a center in which the paint pipe is inserted through the tubular rotary shaft of the air motor There is a feed type.
And, the side feed type is formed with an annular slit or opening through which the paint pipe is inserted on the back side of the rotary atomizing head, and when the paint is supplied to the rotary atomizing head rotating at high speed. The paint may bounce off the slits, etc. and scatter on the back side of the rotary atomizing head to reduce the coating efficiency, or the paint may be charged without being atomized and adhere to the workpiece to cause coating failure. Therefore, recently, a center feed type which does not have such a possibility has become widespread.

When a metallic paint is applied by such a rotary atomizing electrostatic coating machine, a foil-like metal piece contained in the metallic paint is polarized by an electrostatic action, as if flocking on the work surface. As a result, the coating is applied in a certain direction, so that the coating film exhibits an iridescent color whose color changes depending on the viewing direction, or a stripe pattern emerges depending on the condition of the light beam. For this reason, in the case of performing metallic coating, conventionally, it was necessary to use an electrostatic spraying machine of an air atomization type having relatively weak electrostatic action or to apply an air spray gun which does not use electrostatic action at all. .

[0005]

However, the coating efficiency when these coating machines are used is at most 40 to 50% even with an air atomizing type electrostatic coating machine, and 30% with an air spray gun. Is extremely low and the coating efficiency is 80%
Compared to the above-mentioned rotary atomization type electrostatic coating machine, not only waste of paint is large, but also cost is required for exhaust processing when exhausting contaminated air containing paint mist that did not adhere to the work. There was a problem. That is, when the electrostatic action is increased, the coating efficiency is improved, but coating failure occurs. When the electrostatic action is weakened, the coating quality is improved but the coating efficiency is reduced.

Accordingly, the present invention provides a center feed type of supplying paint into a rotary atomizing head from a paint pipe inserted through a tubular rotary shaft of an air motor so that the supplied paint does not scatter from the back side of the rotary atomizing head. The technical problem is to improve both the coating efficiency and coating quality and prevent the coating film from exhibiting iridescent color or striped pattern even when applying metallic paint using an electrostatic coating machine. And

[0007]

Means for Solving the Problems To solve this problem, the first invention of the present application is to provide a rotary atomizing head attached to the tip of a tubular rotary shaft of an air motor to an airframe with its tip exposed. Built-in, paint supplied to the paint chamber in the rotary atomization head from the paint pipe inserted through the tubular rotary shaft,
In an electrostatic coating machine that is atomized from a paint spray slit formed at the tip peripheral portion of the rotary atomizing head and sprays shaping air from the outside of the rotary atomizing head to suppress the spread of the spray paint, In the rotary atomizing head, an air injection slit for injecting stirring air toward the paint sprayed from the paint spray slit is formed in an annular shape along the inside of the paint spray slit. An air chamber for supplying compressed air to the paint chamber is formed on the tip side of the rotary atomizing head with respect to the paint chamber, and the tip of an air pipe inserted inside the paint pipe is formed between the air chamber and the paint chamber. It is characterized in that it is inserted in a non-contact state into a through hole formed in the partition wall and is opened in the air chamber. Further, the second invention of the present application is directed to a rotary atomizing head attached to a tip of a tubular rotating shaft of an air motor, which is built in the body with its tip end surface exposed, and rotated from a paint pipe inserted through the tubular rotating shaft. The paint supplied to the paint chamber in the atomization head is atomized from the paint spray slit formed on the peripheral edge of the tip of the rotary atomization head,
In the electrostatic spraying machine configured to suppress the spread of the spray paint by injecting shaping air from the outside of the rotary atomizing head, the rotary atomizing head is provided with the spray atomized from the paint spray slit toward the sprayed paint. An air injection slit for injecting stirring air is formed annularly along the inside of the paint spray slit, and an air chamber for supplying compressed air to the air injection slit has a rotary atomizing head with respect to the paint chamber. The tip of the tubular rotating shaft is opened to the air chamber, a gap between the tubular rotating shaft and the paint pipe is formed in an air supply channel for supplying compressed air to the air chamber, The paint pipe is characterized in that a tip end of the paint pipe is inserted into a through hole formed in a partition wall between the air chamber and the paint chamber in a non-contact state and is opened in the paint chamber.

[0008]

According to the present invention, first, paint supplied through a paint pipe inserted into the tubular rotary shaft of the rotary atomizing head is atomized by the rotation of the rotary atomizing head and electrostatic force. Spreading is suppressed by the shaping air injected from the outside of the paint spray slit formed in the peripheral portion, and spraying is performed in a predetermined pattern. At this time, the compressed air supplied from the air pipe inserted into the paint pipe into the air chamber of the rotary atomizing head is sprayed toward the spray paint from the air spray slit formed along the inside of the paint spray slit. The air flow becomes a vortex that spreads outward due to the rotation of the rotary atomizing head.

Therefore, when applying a metallic paint, the paint sprayed from the paint spray slit is maintained in a predetermined spray pattern surrounded by shaping air, and a spiral formed inside the paint spray slit. It is agitated by the air flow, and the direction of the metal pieces contained in the paint is uniformly dispersed without being biased in a certain direction, so that the coating film has an iridescent color, without a stripe pattern emerging,
The coating is uniformly finished, and the coating composition is applied to the surface of the work by electrostatic force, so that the coating efficiency does not decrease.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments shown in the drawings. 1 is a cross-sectional view showing an embodiment of the electrostatic coating machine according to the present invention, FIG. 2 is a front view showing an enlarged main part thereof, and FIG. 3 is a cross-sectional view showing another electrostatic coating machine according to the present invention. FIG. 4 and FIG. 4 are sectional views taken along the line AA.

In FIG. 1, reference numeral 1 denotes an electrostatic coating machine in which a rotary atomizing head 2 to which a high voltage is applied is attached to a tip of a tubular rotary shaft 4 of an air motor 3, and the rotary atomizing head 2 has a tip. A paint spray slit 6 is built in the body 5 with its surface exposed, and a paint spray slit 6 for spraying paint supplied through the inside of the tubular rotary shaft 4 by electrostatic atomization is formed in the peripheral edge of the body. And an air jet slit 7 for jetting stirring air toward the paint sprayed from the paint spray slit 6.
Are formed in an annular shape along the inside of the paint spray slit 6.

The rotary atomizing head 2 has a paint chamber 9 in which paint is supplied from a paint pipe 8 which is inserted and supported in a non-contact manner in an annular rotary shaft 4, and a rotary chamber relative to the paint chamber 9. An air chamber 10 is formed at the tip of the atomizing head 2. The paint chamber 9 communicates with the paint spray slit 6 through a radially formed paint passage 9a, and the air chamber 10 communicates with the air injection slit 7 through a radially formed air passage 10a. Have been. Each of the slits 6 and 7 is formed by arranging a large number of slots 6a and 7a at predetermined intervals in an annular shape so that the slit width is not biased. It may be.

An air pipe 11 for supplying compressed air to the air chamber 10 is inserted inside the paint pipe 8 and has a double-pipe structure in which the paint pipe 8 is an outer pipe and the air pipe 11 is an inner pipe. The tip of the paint pipe 8 is opened in the paint chamber 9, and the tip of the air pipe 11 is placed in the paint chamber 9.
Is inserted in a non-contact state into a through hole 13 formed in a partition wall 12 of the air chamber 10, and is opened in the air chamber 10.

The airframe 5 has a shaping air injection slit for injecting compressed air from the outside toward the paint sprayed from the paint spray slit 6 along the outer periphery of the rotary atomizing head 2 to adjust the spray pattern. 14 is formed in an annular shape. The slits 14 are also formed by arranging a large number of slots 14a in a ring shape at predetermined intervals so that the slit width is not deviated. However, even when one continuous slit is formed in a ring shape. Good.

The above is an example of the configuration of the present invention, and its operation will be described below. First, when the annular rotary shaft 4 is rotated while applying a high voltage to the rotary atomizing head 2 and at the same time paint is supplied from the paint pipe 8 inserted into the annular rotary shaft 4, the paint is transferred from the paint chamber 9 to the paint passage. It reaches the tip of the paint spray slit 6 through 9a and is atomized by its rotational force and electrostatic force.

At this time, when compressed air is supplied from the air pipe 11 inserted into the paint pipe 8, the compressed air reaches the tip of the air jet slit 7 from the air chamber 10 through the air passage 10a, and the vortex is generated by the rotational force. Thus, the paint is sprayed from the inside toward the paint sprayed from the paint spray slit 6 from the inside thereof. Simultaneously, when the shaping air is sprayed from the shaping air spray slit 14, the compressed air is sprayed from both the outside and the inside of the paint spray slit 6, so that the paint has not only the rotational force and the electrostatic force but also the force. Since atomization is also performed by air pressure, paint can be atomized and sprayed even if the rotation speed is slightly reduced, and coating defects caused by deformation of metal pieces due to high-speed rotation of the rotary atomizing head 2 are prevented. Can be.

Further, since the shaping air is sprayed to the outside of the atomized paint, the spray is prevented from being spread due to centrifugal force and sprayed in a predetermined pattern.
The metal pieces contained in the coating material are uniformly dispersed without being biased in a certain direction by being stirred by the vortex of the stirring air injected from the inside. Then, the paint components in the paint are applied electrostatically as they are, and the metal pieces are applied in a uniformly dispersed direction, so that the coating film is uniform without iridescent or striped patterns. Finished
There is no decrease in coating efficiency.

FIG. 3 is a sectional view showing another electrostatic coating machine according to the present invention, and FIG. 4 is a sectional view taken along line AA of FIG. 1 and 2 are denoted by the same reference numerals, and detailed description is omitted.

In this embodiment, an air chamber 20 for supplying compressed air to the air injection slit 7 is formed on the back side of the rotary atomizing head 2 with respect to the paint chamber 21. The compressed air is supplied to the air chamber 20 through an air supply passage 4a formed in a gap between the tubular rotary shaft 4 and the paint pipe 22 inserted therein. It is made to be.

Paint pipe 2 for supplying paint to paint chamber 21
Numeral 2 is inserted into the annular rotating shaft 4 in a non-contact state, and its tip is inserted in a non-contact state into a through hole 24 formed in the air chamber 20 and the partition wall 23 of the coating chamber 21 in a non-contact state. It is open. The paint chamber 21 communicates with the paint spray slit 6 through a radially formed paint passage 21a, and the air chamber 20 passes through an air passage 20a formed so as not to intersect with the paint passage 21a. Paint room 2
1 is connected to an annular auxiliary air chamber 25 formed in front of
The sub air chamber 25 is communicated with the air jet slit 7.

When the coating is performed while the shaping air is sprayed from the air spray slit 7 and the shaping air spray slit 14, the compressed air is sprayed from both the outside and the inside of the paint spray slit 6, so that the paint has a rotational force. It can be atomized not only by electrostatic force but also by its air pressure to promote atomization.
At the same time as being sprayed in a predetermined pattern by the shaping air, it is stirred by the vortex of the stirring air injected from the inside, so that the direction of the metal pieces contained in the paint is uniformly dispersed without being biased in a certain direction. The coating film does not exhibit an iridescent color or a striped pattern, is uniformly finished, and does not lower the coating efficiency.

In this embodiment, compressed air is supplied to the air chamber 20 through an air supply passage 4a formed in a gap between the tubular rotary shaft 4 and a paint pipe 22 inserted therein. Since only the paint pipe 22 needs to be inserted into the tubular rotary shaft 4, there is no need to separately provide an air pipe.
As compared with the electrostatic coating machine 1 shown in FIG. 1 in which the air pipe 11 is disposed inside the paint pipe 8, the structure is very simple.

In the description of the embodiment, the case where the shaping air injection slit 14 is formed in the body 5 has been described. The shaping air may be injected from the gap between the body 5 and the body.

[0024]

As described above, according to the present invention, when a metallic paint is applied by electrostatic atomization by rotation of a rotary atomizing head and electrostatic force, the outside of the spray paint is regulated by shaping air. As well as metal pieces in the paint,
It is agitated by the vortex of the agitating air formed inside the spray paint, and the direction of the metal pieces contained in the paint is evenly dispersed without being biased in a certain direction, and the coating film has an iridescent color or stripes. There is an excellent effect that the pattern can be finished uniformly without protruding, and the coating component can be efficiently applied to the surface of the object to be coated by electrostatic force.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of an electrostatic coating machine according to the present invention.

FIG. 2 is an enlarged front view showing a main part thereof.

FIG. 3 is a sectional view showing an example of another electrostatic coating machine according to the present invention.

FIG. 4 is a sectional view taken along line AA.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electrostatic coating machine 2 ... Rotation atomization head 3 ... Air motor 4 ... Tube rotating shaft 5 ... Machine 6 ... Paint spray slit 7 ... Air injection slit 8 ....・ Paint pipe 9 ・ ・ ・ Paint chamber 10 ・ ・ ・ Air chamber 11 ・ ・ ・ Air pipe 12 ・ ・ ・ Partition wall 13 ・ ・ ・ Through hole 20 ・ ・ ・ Air chamber 21 ・ ・ ・ Paint chamber 22 ・ ・ ・ Paint pipe 23 ... Partition walls 24 ... Through holes

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-131159 (JP, A) JP-A-2-152568 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B05B 5/00-5/16

Claims (2)

(57) [Claims] 1. A rotary atomizing head (2) attached to a distal end of a tubular rotary shaft (4) of an air motor (3) is incorporated in an airframe (5) with its distal end surface exposed, and said tubular rotary shaft is provided. The paint supplied to the paint chamber (9) in the rotary atomization head (2) from the paint pipe (8) inserted through (4) is the paint formed on the peripheral edge of the tip of the rotary atomization head (2). In the electrostatic spraying machine which is atomized from the spray slit (6) and sprays shaping air from the outside of the rotary atomizing head (2) to suppress the spread of the spray paint, the rotary atomizing head (2) is used. )
An air injection slit (7) for injecting stirring air toward the paint sprayed from the paint spray slit (6) is formed in an annular shape along the inside of the paint spray slit (6). An air chamber (10) for supplying compressed air to the air injection slit (7) is formed on the tip side of the rotary atomizing head (2) with respect to the paint chamber (9), and the paint pipe (8) is formed. Air pipe (11) inserted inside
Is the partition wall (12) between the air chamber (10) and the paint chamber (9)
An electrostatic coating machine characterized in that it is inserted in a non-contact state through a through-hole (13) formed in a hole, and is opened in an air chamber (10). 2. A rotary atomizing head (2) attached to a distal end of a tubular rotary shaft (4) of an air motor (3) is built in an airframe (5) with its distal end surface exposed, and said tubular rotary shaft is provided. The paint supplied from the paint pipe (22) inserted through (4) to the paint chamber (21) in the rotary atomizing head (2) is formed on the peripheral edge of the tip of the rotary atomizing head (2). In the electrostatic spraying machine which is atomized from the spray slit (6) and sprays shaping air from the outside of the rotary atomizing head (2) to suppress the spread of the spray paint, the rotary atomizing head (2) is used. )
An air injection slit (7) for injecting stirring air toward the paint sprayed from the paint spray slit (6) is formed in an annular shape along the inside of the paint spray slit (6). An air chamber (20) for feeding compressed air to the air injection slit (7) is formed on the back side of the rotary atomizing head (2) with respect to the paint chamber (21), and the tubular rotary shaft ( The tip of 4) is opened to the air chamber (20),
A gap between the tubular rotary shaft (4) and the paint pipe (22) is formed in an air supply passage (4a) for supplying compressed air to the air chamber (20), and the tip of the paint pipe (22) is (20)
Hole (24) drilled in the partition (23) between the paint chamber (21)
An electrostatic coating machine characterized in that it is inserted into the paint chamber (21) in a non-contact state and is opened in the paint chamber (21).