JPH10277437A - Rotary atomizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely impress electric charge to a semiconductive film by providing a semiconductive film and a conductive member comprising a different member from a rotary shaft and connecting the semiconductive film of bell-head to the rotary shaft. SOLUTION: The bell head 1 comprises a high resistance material (non- electrically conductive material) and the semiconductive film 2 is formed on the outer peripheral surface by a method such as by applying a semiconductive coating material. Electric charge supplied from a high voltage generator to the rotary shaft 10 is applied to the semiconductive film 2 through the conductive member 4 which comprises the member different from the semiconductive film 2 and the rotary shaft 10 but electrically conductive to the semiconductive film 2 and the rotary shaft 10. The conductive member 4 is made of a conductive material such as aluminum. As a result, if the semiconductive film 2 is not coated up to the part in contact with the rotary shaft 10 of the bell head 2, electric charge is surely applied to the semiconductive film 2 from the rotary shaft 10 with the conductive member 4. Then, the charge to a coating material particle is stably performed at the tip of the bell head 1 and the excellent sticking effect of coating is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary atomizing electrostatic coating machine in which a bell head is reliably connected to a rotating shaft.

[0002]

2. Description of the Related Art In a rotary atomizing electrostatic coating machine, a bell head (rotary atomizing head) is rotationally driven at a high speed by an air motor using an air bearing. The paint is supplied to the bell head and atomized. Further, in order to improve the coating efficiency, coating is performed by applying static electricity to the bell head and applying a charge to the paint from the bell head. In general, a rotary atomizing electrostatic coating machine is composed of a conductor mainly composed of light metal.
Therefore, when static electricity is applied, a considerable amount of electrostatic energy is accumulated, and during electrostatic coating, when a ground object approaches or approaches a ground object at a certain speed or more, static electricity is generated between the object and the ground object. Generates electric spark. In the case of coating an intruded portion such as the inner plate coating of an automobile, there is a great possibility that the portion comes close to a grounded object. Therefore, conventionally, for example, in Japanese Unexamined Patent Publication No. 8-150352, as shown in FIG. Is applied, and a bell head 21 made of resin and having a semiconductive film 22 formed on the outer peripheral surface is used. In that case, the static electricity is applied from the high voltage generator via the rotating shaft 30 to the semiconductive film 22 applied so as to contact the rotating shaft 30.

[0003]

However, it is difficult to apply the paint to the end face of the bell head 21, and even if it can be applied, there is a possibility that the paint is immediately peeled off. In this case, no static electricity is applied to the semiconductive film 22 from the rotating shaft 30, and no charge can be applied to the paint atomized by the bell head 21, thereby lowering the coating efficiency. SUMMARY OF THE INVENTION An object of the present invention is to provide a rotary atomizing electrostatic coating machine that can reliably apply static electricity to a semiconductive film.

[0004]

According to the present invention, there is provided a bell head having a semiconductive film formed on an outer peripheral surface thereof and made of a high resistance material, a rotating shaft connected to the bell head, the semiconductive film and the rotating shaft. A rotary atomizing electrostatic coating machine comprising: a semiconductive film made of a separate member; and a conductive member that conducts between the semiconductive film and the rotating shaft.

[0005] The rotary atomizing electrostatic coating machine of the present invention has a semiconductive film and a semiconductive film of a bell head, which is a member separate from the rotating shaft, and a conductive member for conducting the rotating shaft. Therefore, even if the bell head and the rotating shaft are not conducted by the semiconductive film, they are always conducted by the conductive member, and the static electricity is reliably applied to the semiconductive film. Therefore, a decrease in the coating efficiency is prevented.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A rotary atomizing electrostatic coating machine according to a preferred embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a schematic sectional view of a bell head portion of the rotary atomizing electrostatic coating machine according to the embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view of the rotary atomizing electrostatic coating machine according to the embodiment of the present invention. FIG. 3 is a schematic sectional view of a bell head portion of a rotary atomizing electrostatic coating machine according to another embodiment of the present invention. As shown in FIG. 2, a rotary atomizing electrostatic coating machine 3 according to an embodiment of the present invention includes a bell head (rotating atomizing head) 1 for atomizing paint, and a hollow connected to the bell head 1 and rotating integrally with the bell head 1. Rotating shaft 10 and rotating shaft 10
An air motor 6 (including an air bearing for rotatably supporting the rotating shaft 10), and a paint feed tube 5 extending through the hollow portion of the rotating shaft 10 to the inside of the bell head 1 and supplying paint to the bell head 1. An air cap 11 having an air nozzle for ejecting shaping air forward from the outer peripheral edge of the bell head 1 toward the paint scattered radially outward; a high voltage generator 7 for generating a high voltage applied to the bell head 1; And a casing 12. The air cap 11 and the casing 12 are made of a high-resistance resin (for example, polyether ether ketone,
Polyetherimide, polyacetal, etc.). The bell head 1 has a paint ejection hole 1a formed in the outer peripheral portion of a wall portion facing the tip of the paint feed tube 5 and through which paint passes at the time of painting, and a self-cleaning passage formed at the center of the wall portion and through which a cleaning agent passes during washing. Route 1b
And

As shown in FIG. 1, the bell head 1 is made of a high-resistance material (non-conductive material), and a semi-conductive film 2 is formed on the outer peripheral surface by applying a semi-conductive paint. ing. On the semiconductive film 2, the static electricity supplied from the high voltage generator 7 to the rotating shaft 10 is formed by a member separate from the semiconductive film 2 and the rotating shaft 10.
Is applied through the conductive member 4 that conducts the current. The conductive member 4 is made of a conductive material (for example, aluminum). In the case of the embodiment of the present invention, as shown in FIG.
A part of the bell head 1 made of a high-resistance resin is made of a conductive material, and this part is used as a conductive member 4. The conductive member 4 has a substantially cylindrical shape, has an axial length from the threaded portion 15 of the bell head 1 to the tapered portion 16, the inner periphery of the cylinder is in contact with the rotating shaft 10, and the rear portion 4a is a semiconductive film. 2 and protrude radially outward so as to come into contact with 2. As another example of the conductive member 4, as shown in FIG. 3, one end is connected to the rotating shaft 10, the other end is in contact with the semiconductive film 2, and the rotating shaft 10 and the semiconductive film 2 are connected to each other. There are a plurality of pin-shaped conductive pins 4 provided to be conductive.

The paint particles atomized by the rotation of the bell head 1 are charged by the semiconductive film 2 at the tip of the bell head 1, and are efficiently applied to the object by electrostatic force.

The high-resistance material (non-conductive material) constituting the bell head 1 is, for example, a resin material. In this resin material,
For example, it contains super engineering plastic materials,
Examples of this super engineering plastic material include:
It includes polyetherimide, a thermoplastic special engineering plastic, and polyetheretherketone, a thermoplastic superengineering plastic.

The semiconductive film 2 formed on the outer peripheral surface of the bell head 1 is made of a phenolic resin such as carbon (other than carbon as long as it is conductive fine particles).
And those containing carbon (other than carbon as long as fine particles of conductive material) in an epoxy resin. When the thickness or composition of the semiconductive film 2 changes due to erosion of a chemical or a solvent from the outside, the electrical resistance changes, and there is a possibility that the coating efficiency may be reduced. It is desirable to form a chemical-resistant and solvent-resistant high-resistance (non-conductive) film on the outer peripheral surface of 2. Materials forming the non-conductive film include phenol resin, epoxy resin, polytetrafluoroethylene, and the like.

Next, the operation will be described. The semiconductive film 2 formed on the outer periphery of the bell head 1 is formed of a member separate from the semiconductive film 2 and the rotating shaft 10 via a conductive member 4 that conducts the semiconductive film 2 and the rotating shaft 10. , The static electricity from the rotating shaft 10 is applied. Therefore, even if the semiconductive film 2 is not applied to a portion in contact with the rotating shaft 10 of the bell head 1, static electricity is reliably applied from the rotating shaft 10 to the semiconductive film 2 by the conductive member 4. Therefore, the coating particles are stably charged at the tip of the bell head, and good coating efficiency can be secured. In addition, since the bell head 1, the air cap 11, the casing 12, and the like can be formed of a resin instead of a conductor centered on a light metal, the amount of electrostatic energy stored in the electrostatic coating machine is reduced,
Electrostatic spark is less likely to occur.

[0012]

According to the present invention, the semiconductive film formed on the outer peripheral surface of the bell head is made of a member different from the semiconductive film and the rotating shaft, and conducts the semiconductive film and the rotating shaft. Static electricity is reliably applied from the rotating shaft via the conductive member. Therefore, static electricity is stably applied to the paint particles, and a decrease in the coating efficiency of the paint particles is suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a bell head portion of a rotary atomizing electrostatic coating machine according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view of a rotary atomizing electrostatic coating machine according to an embodiment of the present invention.

FIG. 3 is a schematic sectional view of a bell head portion of a rotary atomizing electrostatic coating machine according to another embodiment of the present invention.

FIG. 4 is a schematic sectional view of a bell head portion of a conventional rotary atomizing electrostatic coating machine.

[Explanation of symbols]

 Reference Signs List 1 bell head 2 semiconductive film 3 rotary atomizing electrostatic coating machine 4 conductive member 10 rotating shaft

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Y. Tomita 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation

Claims (1)

[Claims] 1. A bell head having a semiconductive film formed on an outer peripheral surface thereof and made of a high resistance material, a rotating shaft connected to the bell head, and a member separate from the semiconductive film and the rotating shaft. A rotary atomizing electrostatic coating machine, comprising: a conductive member that conducts between the semiconductive film and the rotating shaft.