JPS6135868A - Rotary atomizing head of painting apparatus - Google Patents

Abstract

PURPOSE:To obtain the rotary atomizing head excellent in abrasion resistance and having long life of a painting apparatus, by applying hardening treatment such as nitriding treatment to a flowing surface containing a paint discharge part. CONSTITUTION:In a rotary atomizing head 3 made of an aluminum alloy, hardening treatment such as nitriding treatment, titanium nitride treatment or alumite treatment is performed to a flowing surface containing a paint discharge part 16. By this method, the apint flowing surface is hard to abrade and excellent in abrasion resistance and has long service life.

Description

[Detailed description of the invention] The present invention relates to a rotating atomizing head for a coating device.

Conventional single-rotation atomizing type painting equipment has a rotary atomizing head attached to the rotating shaft of a rotary drive device, and a paint supply path is connected to the base end of the single-rotation atomizing head. A paint flow surface is formed on the peripheral surface, and a paint discharge part is formed at the tip of the paint flow surface. In recent years, in order to increase the rotation speed of the rotary atomizing head and improve the atomization performance of paint, an air turbo motor that rotates at high speed has been used as a single rotation drive device. 1 rotation atomization head.

In order to reduce weight, it is manufactured from aluminum alloy, which is light, easy to machine, and inexpensive.

However, the rotating atomizer head made of aluminum alloy.

Since the paint flows on the paint flow surface while being pressed against it by centrifugal force, the paint flow surface, especially the paint discharge part, is easily worn out.

In the case of electrostatic coating equipment, the paint discharge part of the one-turn atomizing head also serves as a charging electrode, so if the sharpness decreases due to wear, the amount of charge on the paint particles decreases, and the coating efficiency decreases. It becomes like this.

In addition, if a paint flow part is provided on the paint flow surface of the rotating atomizer head to prevent air from being drawn into the paint particles, if the paint flow part wears out, air will be drawn into the paint particles. , paint defects will occur.

That is, the rotating atomizing head made of aluminum alloy has a diagonal flow surface that is easily worn, has poor wear resistance, and has a short lifespan.

An object of the present invention is to provide a rotary atomizing head for a coating device that has excellent wear resistance and has a long life.

The present invention provides a rotating atomizing head made of aluminum alloy,
The paint flow surface, including the paint discharge area, is subjected to hardening treatments such as nitriding treatment, titanium nitride treatment, and alumite treatment.

Since the paint flow surface of this rotary atomizing head is hardened, the paint flow surface is less likely to wear out, has excellent abrasion resistance, and has a long life. Moreover, the advantages of aluminum alloy being light and easy to machine are not lost. In addition, the hardened coating fluid surface has excellent corrosion resistance.

Next, one embodiment of the present invention will be described.

The coating device equipped with a rotating atomizing head of this example has a rotary shaft (2) protruding from the tip of the case of an air turbo motor (1) with a maximum rotation speed of 60,000 revolutions per minute, as shown in Fig. 1. Insert the aluminum alloy hub (3) for expansion into which the disc part (5) is connected concentrically to the tip of the cylindrical part (4), and drill into the center of the disc part (5) of the hub. Tapered mounting hole (6)
The tapered tip of the rotating shaft (2) of the air turbo motor is tightly fitted into the hub, and the screw (
7) connects the hub (3) to the rotating shaft of the air turbo motor (
2) is attached concentrically to the hub (3), and a cylindrical part (9) with a bowl-shaped cylindrical part 00 concentrically connected to the hub (3) is attached to the hub (3). Insert the cylindrical part of the hub (
Fitting the bell-shaped cylindrical part (9) onto the outer periphery of 4), protruding the bell-shaped bowl-shaped cylindrical part αO to the front position of the hub (3),
The bell-shaped body (8) is concentrically attached to the hub (3) by screws 0υ screwed into the peripheral wall of the cylindrical part (9) of the bell-shaped body, and the hub (3) made of expanded aluminum alloy and the bell are integrated. The feature (8) constitutes a rotating atomizing head. The rotating atomizing heads (3) and (8) are connected to a DC high voltage generator (not shown) via an air turbo motor (1).

Also serves as a charging electrode. A paint supply pipe (L4) connected to a paint supply device (not shown) is attached to the tip of the case of the air turbo motor (1), and the tip opening of the paint supply pipe (2) is inserted into the cylindrical part αΦ of the hub of the rotating atomizing head. The paint supply path (2) is connected to the hub (3) on the proximal end side of the rotary atomizing head.A bell-shaped bowl-shaped cylindrical portion is attached to the distal end peripheral wall of the cylindrical portion (4) of the hub. A large number of paint passage holes 01 communicating with QQ are provided at equal intervals, and the inner peripheral surface of the bell-shaped bowl-shaped cylindrical portion αQ is formed as a paint flow surface Q4.The tip of the paint flow surface (B). As shown in Figures 1 and 2.

A paint distribution part (end) is formed with a large number of grooves arranged at equal intervals along the axial direction, and the tip edge of the paint flow surface 04, that is, the tip opening edge of the rotating atomization heads (3) and (8). is used as the paint discharge part QG. Further, at the tip of the case of the air turbo motor (1), a rotating atomizing head (3
), (8) are installed concentrically, and the UEU atomizing head (3
).

The annular air pipe αη located at the rear of (8) has a number of air injection holes (
) are set at equal intervals.

Aluminum alloy bell shape (8
) is hardened by nitriding the surface of the first cylindrical portion (9) except for the inner circumferential surface.

The nitriding treatment is performed as follows.

■Clean the bell shape (8) and place it in a container.

■Remove oxygen gas inside the container. This is done by evacuating the inside of the container to reduce the pressure to /0) l (Torr, txHf), injecting hydrogen gas therein, replacing the oxygen gas in the container with hydrogen gas, and repeating this replacement.

■Inject argon gas into the container to reduce the pressure of the gas.
At the same time as holding it in the tor, several hundred points/7)
voltage is applied to generate a glow discharge.

The surface of the bell-shaped body (8) is activated by raising the temperature to a nitriding temperature of about 500° C., and glow discharge is maintained at that temperature for 7 hours to clean the surface of the bell-shaped body (8).

■Inject nitrogen gas instead of argon gas into the container and maintain the nitrogen gas pressure at 3.5 Torr.

Glow discharge is continued for 5 hours to perform ion nitriding.

A layer of aluminum nitride with a thickness of several microns is then formed on the surface of the bell-shaped body (8).

(2) Stop the injection of nitrogen gas into the container and the application of voltage to the bell-shaped body (8), reduce the pressure inside the container to 10 Torr, and allow the bell-shaped body (8) to cool.

■Bell-shaped body with aluminum nitride layer formed on the entire surface (
8) is taken out from the container and the inner circumferential surface of the first cylindrical portion (9) is polished to remove the aluminum nitride layer on the inner circumferential surface.

When the coating apparatus equipped with the rotating atomizing head of this example is driven, the lightweight rotating atomizing heads (3) and (8) rotate at high speed due to the rotational drive of the air turbo motor (1), and the A DC high voltage is applied between the rotating atomizing heads (3), (8) and the object to be painted (not shown) located in front of them, and air is emitted from the air injection hole (to) of the air pipe for adjusting the coating pattern.
The air is ejected forward, and some of the paint from the paint supply path (2) is poured into the hubs at the proximal ends of the rotary atomizing heads (3) and (8). The paint is fed into the hub (3) of the rotating atomizing head during rotation.

Due to the centrifugal force, the paint reaches the bowl-shaped cylindrical part 0Q of the bell-shaped body through a large number of paint passage holes (2), and flows in the form of a thin film over the hardened paint flow surface α in the bowl-shaped cylindrical part αQ. The paint flows into the many grooves of the paint distribution part Q9, is divided into many liquid streams, and is discharged radially from the paint discharge part αQ, where it is atomized into fibrous particles. At that time, the paint particles are charged by the corona discharge generated in the paint discharge part DI, and the charged paint particles are directed toward the object to be coated by adjusting the flight direction by the air ejected from the air injection hole. and adheres to the object being painted.

The rotating atomizing head in this example has a paint distribution part (to) and a paint discharge part a.
The paint flow surface α containing Q is hardened and an aluminum nitride layer with a thickness of about 5 microns and a Vickers hardness of about 2000 is formed on the surface α→.

Vickers hardness without hardening treatment is 30 to /I
Compared to conventional products, AO'''c has higher wear resistance and corrosion resistance, and has a lifespan approximately 2.5 times longer.In addition, the μ-shaped bowl-shaped cylindrical portion 00, which becomes a charging electrode, has an insulating surface. Although it forms a sensitive aluminum nitride layer, there is no problem as a charging electrode.
Coating characteristics 1, such as the amount of charge on the coating particles and coating efficiency, are the same as those of conventional products that do not have an aluminum nitride layer.

In the above embodiment, the paint flow surface Q4 of the one-rotation atomizing head
Although nitriding treatment was used for the hardening treatment, titanium nitride treatment by ion blating, reactive sputtering, plasma 0VD, etc. may also be used. When a titanium nitride coating is formed with a thickness of about S microns and a Vickers hardness of about UOOOO, it has higher wear resistance and corrosion resistance than conventional products, and has a longer lifespan, as in the above example. The coating performance is approximately 2.5 times that of conventional products.

In addition, by using hard alumite treatment to form an alumite coating with a thickness of approximately 10 microns and a Vickers hardness of approximately 300, it has higher wear resistance and corrosion resistance than conventional products, and has approximately twice the lifespan. ,Also.

The same coating performance as conventional products can be obtained. Hard alumite treatment is less expensive than nitriding treatment and titanium nitride treatment, but the Vickers hardness of the hardened layer is low and the effect of extending life is small. The Vickers hardness of the flow surface of the cured paint is preferably 1000 or more.

Moreover, in the above embodiment, there is a one-rotation atomizing head (3).

This was an electrostatic coating device that also used (8) as a charging electrode.

A non-electrostatic coating device in which the rotating atomizing head is not also used as a charging electrode may be used. Also, the shapes of the single-rotation atomizing heads (3) and (8) are as follows.

Although it is bowl-shaped, it may also be cylindrical or dish-shaped.

In addition, the paint distribution part (to) had a large number of grooves lined up at the tip of the paint flow surface Q41, but it also had a number of holes lined up or the tip edge of the paint flow surface Q41 had a serrated shape. It may also be a formed one.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway side view of a coating device equipped with a rotating atomizing head according to an embodiment of the present invention, and FIG. 2 is a front view of the same coating device. 1: Air turbo motor 1-rotation drive device 3.8 2-rotation atomizing head 12: Paint supply pipe, paint supply path 14: Paint flow surface 16: Paint discharge part

Claims (2)

[Claims] (1) Attach a rotating atomizing head made of aluminum alloy to the rotating shaft of the rotary drive device, connect a paint supply path to the base end of the rotating atomizing head, and apply paint to the inner circumferential surface of the tip of the rotating atomizing head. 1. A rotary atomizing head in a coating device having a fluidizing surface and a paint discharging section formed at the tip of the paint fluidizing surface, characterized in that the paint fluidizing surface including the paint discharging section is hardened. (2) The rotary atomizing head according to claim 1, wherein the hardened surface has a Vickers hardness of 1.000 or more.