JP2747439B2 - Electrostatic coating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating cup type electrostatic coating apparatus, and more particularly to a technique for averaging the supply of paint to a knife edge portion of the rotating cup in a circumferential direction of the rotating cup.

[0002]

2. Description of the Related Art A rotating cup type electrostatic coating apparatus is known from Japanese Patent Publication No. 5-56189. This conventional electrostatic coating apparatus is as shown in FIGS. 6 and 7, in which an outer cylinder 2 is integrally provided on an outer peripheral portion of a bottomed cylindrical rotating cup 1 with an air ejection path 7 therebetween. An air supply pipe 5 is extended behind the center of the bottom of the air supply pipe 1. A plurality of air supply holes 6 are formed in the radial direction of the rotary cup 1 from the air supply pipe 5 and the tip of the air supply hole 6 is blown out with air. A plurality of paint supply holes 4 are formed in the bottom of the rotary cup 1 on the outer peripheral side of the air supply pipe 5 to reach the inside of the rotary cup 1 so as to penetrate the rotary cup 1 in the circumferential direction. The coating material supplied to the peripheral surface is sent forward in a thin film shape with rotation, and the coating material is electrostatically atomized from the knife edge portion 12 at the tip of the rotating cup 1.

In this conventional electrostatic coating apparatus, a plurality of air supply holes 6 are formed radially in the radial direction of the rotating cup 1, and a plurality of paint supply holes 4 are formed between adjacent air supply holes 6. doing. Therefore, the distance L between the adjacent paint supply holes 4 formed between the air supply holes 6 shown in FIG.
₁ is different from the interval L ₂ between the paint supply holes 4 adjacent to each other via the air supply hole 6.

[0004]

As described above, in the conventional electrostatic coating apparatus, the interval between the plurality of coating supply holes 4 provided in the circumferential direction at the bottom of the rotating cup 1 is not uniform. The supply of the paint in the circumferential direction at the tip of the knife edge portion 12 cannot be averaged, and the thickness of the paint becomes non-uniform. As a result, there is a problem that the paint cannot be atomized as uniform particles.

In view of the above, the present invention has been made to solve the above-mentioned problems and to provide an electrostatic coating apparatus for equalizing the supply of paint in the circumferential direction at the tip of the knife edge to make the paint thickness uniform and atomizing the paint as uniform particles. To offer.

[0006]

In order to solve the above-mentioned problems, an electrostatic coating apparatus according to the present invention is a so-called rotary cup type electrostatic coating apparatus, wherein a plurality of rotary cups formed radially in a radial direction on a rotary cup 1 are provided. The opening angle between the adjacent air supply holes 6 of the air supply holes 6 is fixed, and the rotating cup
1 has a receiving surface substantially parallel to the rotation axis of the rotation cup 1
Forming a recessed step with a 9, above the bottom of the rotary cup 1
A plurality of paint supply holes 4 are formed in the concave step portion 10 at regular intervals in the circumferential direction, and the receiving surface is substantially parallel to the rotation axis of the concave step portion 10.
9, fine irregularities 11 are formed, and the paint supply holes 4 and the air supply holes 6 are alternately arranged one by one in the circumferential direction, and each paint supply hole 4 is located between the adjacent air supply holes 6. It is characterized by being arranged.

[0007]

Embodiments of the present invention will be described below. 1 to 5 show an embodiment of the present invention. The outer cylinder 2 is fixed to the rotating cup 1 by fitting the outer cylinder 2 into the outer periphery of the rotating cup 1 via the air ejection path 7 and screwing the fixing ring 13 to the outer periphery of the rotating cup 1 behind the outer cylinder 2. I have to do it. The rotating cup 1 is formed by a front cylinder part 14, a rear cylinder part 15, and an air supply pipe 5, and a bottom part 3 is formed between the front cylinder part 14 and the rear cylinder part 15.
The air supply pipe 5 projects rearward from the bottom 3. This air supply pipe 5 may be divided in its length direction.

The inner peripheral surface of the front cylinder portion 14 is formed as a tapered surface which increases in diameter toward the front, and the inner peripheral surface of the rear cylinder portion 15 is also formed as a taper surface which expands in the forward direction. is there. The front end of the front tube portion 14 is formed as a knife edge portion 12 having a sharp end over the entire circumference. The air supply pipe 5 is a rotating shaft part, is formed by a hollow cylinder provided with an air passage 16 at the center thereof, and is opened rearward. The air supply pipe 5 radially extends in the radial direction of the rotating cup 1 near the bottom part 3. , A plurality of air supply holes 6, 6... Are communicated with the air ejection path 7, and the front end of the outer cylinder 2 and the rotary cup 1
An air outlet 17 formed in a narrow slit shape over the entire periphery is formed between the knife edge portion 12 and the vicinity of the trailing edge.

Here, the opening angle formed between adjacent air supply holes 6 of the plurality of air supply holes 6 formed radially in the radial direction is constant. Also, the bottom 3 of the rotating cup 1
A plurality of paint supply holes 4 are formed in a peripheral portion of the front cylinder portion 14 and the rear cylinder portion 15 through the paint supply holes 4.
And are communicated. Here, the plurality of paint supply holes 4 formed in the circumferential direction are formed at regular intervals.

The paint supply holes 4 and the air supply holes 6 are alternately arranged one by one in the circumferential direction. Each paint supply hole 4 is arranged in the middle of the adjacent air supply hole 6. It is. Here, each of the plurality of paint supply holes 4 formed at regular intervals in the circumferential direction as described above has an air supply hole 6 formed at regular intervals in the circumferential direction and an adjacent air supply hole 6. In order to form the plurality of air supply holes 6 and the plurality of paint supply holes 4 so as to be located in the middle of the above, the following is performed.

That is, as shown in FIG. 4A, the paint supply holes 4 are formed at regular intervals in the circumferential direction at the bottom of the rotary cup 1 and the air supply holes 6 are formed one by one between the paint supply holes 4. Formed. In this case, the end of the air supply hole 6 having a small diameter is chipped or burred. In particular, since the ends of the air supply hole 6 on the air passage 16 side are too close to each other, the air supply If the ends of the holes 6 are chipped or burrs are generated, there is a possibility that it is difficult to uniformly supply air from the air supply holes 6. Therefore,
As shown in FIG. 4B, a hole 50 is formed in the bottom of the rotating cup 1 to remove an inner end portion of the air supply hole 6.
In addition, a cutout portion 52 is formed by cutting out a base portion of the rear tube portion 15 protruding from the front tube portion 14 of the rotary cup 1, and by forming the cutout portion 52 in this manner, the outer end of the air supply hole 6 is formed. The part is removed. Then, FIG.
Only the first half of the hole 50 is buried with the lid 51 as shown in FIG. By forming the hole 50 and filling only the first half of the hole 50 with the lid 51, the radially formed air supply hole 6 is opened at the hole 50. As a result, The gap between the end portions of the adjacent air supply holes 6 is increased, and the hole portions 50 are formed and the cutout portions 52 are formed to form the inner end portions of the air supply holes 6 in FIG. In addition, it is possible to remove a chipped portion or a burr generated portion of the outer end portion, so that air supplied from the front end of the air passage 16 to the hole portion 50 can be removed.
From around 0, the air is supplied uniformly to each air supply hole 6, and the air is uniformly supplied from each air supply hole 6 to the air ejection path 7 through the cutout 52.

The rotary cup 1 formed as described above is formed by screwing a screw portion 20 at the rear end of the air supply pipe 5 serving as a rotary shaft portion to a distal end of a relay pipe shaft 21 as shown in FIG. The relay pipe shaft 21 is rotatably driven by an air motor 22 which is operated by receiving a supply of compressed air. Air motor 2
2, a pressure air supply device 23 such as a compressor is connected by piping, and a pressure cylinder 23 supporting the relay pipe shaft 21 is also connected with a pressure air supply device 23 by piping. The compressed air is supplied to the air passage 16 of the air supply pipe 5 through the shaft 21.

A paint supply pipe 2 led from a paint supply device 27 formed by a paint pump, a paint tank, or the like.
8 is inserted into the rear cylinder portion 15 of the rotary cup 1, and the lead 30 of the high voltage generator 29 is connected to the terminal 31 of the bearing cylinder 24 to charge the rotary cup 1 to a negative high potential. Then, a high potential difference is provided between the object 32 and the object 32 to be grounded.

In the electrostatic coating apparatus having the above-described structure, when the rotary cup 1 is rotated by the rotation of the relay pipe shaft 21 by the air motor 22 and the paint is supplied to the rotary cup 1 from the paint supply pipe 28, The paint moves forward along the inner peripheral taper surface of the rear cylinder portion 15 and moves from the paint supply hole 4 to the inner peripheral surface of the front cylinder portion 14, and the paint is formed into a thin film by centrifugal force caused by the rotation of the rotary cup 1. The paint spreads uniformly and thinly and reaches the knife edge portion 12 at the tip, and the paint is discharged from the knife edge portion 12 in a negatively charged atomized state, adheres to the workpiece 32 by electrostatic action, and paints on the surface. Can be formed. On the other hand, the air supply pipe 5
The compressed air supplied to the air passage 16 passes through the air supply hole 6, passes through the air ejection path 7, and passes through the air ejection port 1.
7 and is ejected forward from the air ejection port 17 over the entire periphery of the rear edge of the knife edge portion 12. In this way, the air jetted from the air jet port 17 becomes shaving air which has been swirled with the rotation of the rotary cup 1, and the paint discharged from the knife edge portion 12 is surrounded by the shaving air. This prevents the paint from scattering due to the centrifugal force caused by the rotation of the paint. Here, each of the plurality of paint supply holes 4 formed at a constant interval in the circumferential direction is formed between an air supply hole 6 formed at a constant interval in the circumferential direction and an adjacent air supply hole 6. The knife edge 1 of the rotating cup 1
(2) The paint supply in the circumferential direction of the two tips can be averaged. As described above, the supply of the paint in the circumferential direction at the tip of the knife edge portion 12 can be averaged, so that the thickness of the paint in the circumferential direction at the tip of the knife edge portion can be made uniform. Further, since the air supply holes 6 are also formed radially at the same opening angle, the air supply holes 6 are uniformly supplied from the air supply holes 6 radially arranged in the air ejection path 7, and the knife edge portion 12 of the rotary cup 1 is formed. Is supplied uniformly in the circumferential direction, and as a result, the paint can be atomized as uniform particles.

[0015] In the present invention, the accompanying drawings as shown in a, is formed a recessed step 10 having a rotational axis direction substantially parallel to the receiving surface 9 of the rotary cup 1 to the bottom 3 of the rotary cup 1. By forming the concave step portion 10 in this manner, the paint supplied from the paint supply hole 4 in the bottom 3 of the rotating cup 1 passes through the concave step portion 10 and passes through the inner peripheral side wall 8 of the rotating cup 1 into the knife. To proceed to the edge portion 12, the concave step portion 10
Is higher than the lower layer traveling speed, which is lower in resistance than the lower layer traveling speed, which advances while receiving the resistance while adhering to the receiving surface 9 of the concave step portion 10. In this way, the surface paint advances faster. The paint is spread laterally under the force of components also in the direction perpendicular to the direction of the rotation axis of the rotating cup 1, so that the paint supply holes 4 are arranged around the bottom 3 of the rotating cup 1 in the circumferential direction. However, the supply of the paint to the knife edge portion 12 at the tip end of the rotating cup 1 can be equalized in the circumferential direction thereof, and the thickness of the paint can be equalized in the circumferential direction of the knife edge portion 12, so that the paint can be uniform as particles. Is atomized.

Further, fine irregularities 11 are formed on the receiving surface 9 of the concave step portion 10 . Thus, the fine irregularities 11 are formed on the receiving surface 9.
Is formed, the resistance of the receiving surface 9 is increased, the traveling speed of the lower layer is reduced when the paint advances in the concave step portion 10, the relative speed difference from the surface layer speed is increased, and the one-layer paint is moved in the lateral direction. It increases the spreadability .

[0017]

According to the present invention, as described above, the opening angle formed between adjacent air supply holes of a plurality of air supply holes formed radially in the radial direction is made constant, and a certain interval is formed in the circumferential direction. A plurality of paint supply holes are formed at intervals, and the paint supply holes and the air supply holes are alternately arranged one by one in the circumferential direction, and each paint supply hole is arranged in the middle of the adjacent air supply hole. Because there is, the supply of paint in the circumferential direction of the tip of the knife edge of the rotating cup can be averaged,
The thickness of the paint in the circumferential direction at the tip of the knife edge can be made uniform, and the air supply holes are also formed radially at the same opening angle, so that the air supply holes arranged radially in the air ejection path It is supplied uniformly and is supplied uniformly in the circumferential direction of the knife edge portion of the rotating cup, so that the paint can be atomized as uniform particles. The rotation axis of the rotation cup is located on the bottom of the rotation cup.
Forming a concave step with a receiving surface substantially parallel to the
Paint on the concave step at the bottom of the
A plurality of supply holes are formed and are substantially parallel to the rotation axis of the concave step.
Since the receiving surface has fine irregularities, the bottom of the rotating cup
The paint supplied from the paint supply hole of
Go to the knife edge through the inner side wall of the cup
In addition, the speed of the paint at the concave step is dependent on the receiving surface of the concave step.
Resistance compared to the lower layer traveling speed that advances while receiving resistance while wearing
The surface speed of the surface layer is low, and the coating of the surface layer
As it progresses quickly, the paint on the surface layer is in the direction of the rotation axis of the rotating cup.
It also spreads in the horizontal direction by receiving a component force in the direction orthogonal to
Thus, the paint supply hole is located at the bottom of the rotating cup in the circumferential direction.
The tip of the rotating cup is
Even supply of paint to the if-edge in the circumferential direction
Paint thickness in the circumferential direction around the knife edge.
Atomizes paints as uniform and uniform particles
It is possible to form fine irregularities on the receiving surface.
Therefore, the resistance of the receiving surface is increased, and the paint progresses in the concave step.
In this case, the speed of the lower layer is slowed down,
Increased speed difference further increases the spreadability of paint in the horizontal direction
It is.

[Brief description of the drawings]

FIG. 1 is a sectional view of a rotating cup of an electrostatic coating apparatus according to the present invention.

FIG. 2 is a front view of the rotary cup.

FIG. 3 is a schematic reduced view showing the whole of the same.

FIGS. 4 (a), (b) and (c) are explanatory views showing the processing order of the above.

FIG. 5 is a partially broken perspective view of the same.

FIG. 6 is a sectional view of a conventional rotating cup.

FIG. 7 is a plan view of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotating cup 2 Outer cylinder 3 Bottom part 4 Paint supply hole 5 Air supply pipe 6 Air supply hole 7 Air ejection path 12 Knife edge

Claims (1)

(57) [Claims] An outer cylinder is integrally provided on an outer peripheral portion of a bottomed cylindrical rotating cup with an air ejection path therebetween, and an air supply pipe is extended behind a central portion of a bottom of the rotating cup, and an air supply pipe is provided. A plurality of air supply holes are formed radially in the radial direction of the rotary cup, and the tip of the air supply hole reaches the air ejection path, and is circumferentially spaced from the bottom of the rotary cup on the outer peripheral side of the air supply pipe. A plurality of paint supply holes reaching the inside of the rotating cup with a gap therebetween, and the paint supplied to the inner peripheral surface of the rotating cup is sent forward in a thin film form with the rotation, and a knife edge portion at the tip of the rotating cup is formed. In an electrostatic coating device that electrostatically atomizes paint, the opening angle between adjacent air supply holes of a plurality of radially formed air supply holes is kept constant, and the rotation of the rotation cup at the bottom of the rotation cup axis
A concave step having a receiving surface substantially parallel to the core direction is formed, and a plurality of paint supply holes are formed in the concave step at the bottom of the rotary cup at regular intervals in the circumferential direction, and the rotation axis of the concave step is formed. Almost parallel to the direction
Form fine irregularities on the receiving surface, alternately arrange the paint supply holes and air supply holes one by one in the circumferential direction, and arrange each paint supply hole in the middle of the adjacent air supply hole respectively An electrostatic coating apparatus characterized by comprising: