JP3947282B2 - Rotating atomizing spray gun - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotary atomizing type spray gun for spraying paint in a mist form by centrifugal force from an atomizing head attached to a shaft rotating at a high speed.
[0002]
[Prior art]
In the spray gun configured as described above, since the shaft rotates at a high speed, normal sliding bearings and rolling bearings cannot be used, and a large number of small holes are formed in the bearing cylinder so that a slight gap between the shaft and the air Generally, a gas bearing is used in which a shaft is supported in a state of being floated from a bearing cylinder by blowing compressed gas or the like.
[0003]
[Problems to be solved by the invention]
In such spray guns, at the end of the painting operation, the tip part including the atomizing head is immersed in a solvent and the atomizing head is rotated at a low speed, so that the attached paint is washed off. In addition, the solvent in which the paint has dissolved penetrates into the gap between the bearing cylinder and shaft of the gas bearing due to capillary action, and after the solvent evaporates, the paint hardens and clogs the gap, preventing the shaft from rotating and burning the shaft and bearing cylinder. There was a risk of attaching.
[0004]
[Means, actions and effects for solving the problems]
As a means for solving the above-mentioned problems, the present invention is directed to the portion corresponding to the tip of the gas bearing on the outer peripheral surface of the shaft and to the outside of the gas bearing in the gap with the bearing cylinder by the rotation in the same direction as that during painting. Since the spiral groove that is twisted in the direction in which the airflow is generated is formed, if the shaft is rotated at a low speed during cleaning, the contaminated solvent trying to enter between the shaft and the bearing cylinder is pushed out of the gas bearing.
[0005]
Therefore, there is an effect that it is possible to reliably prevent the rotation of the shaft and the shaft and the bearing cylinder from being seized by solidifying and clogging the gap after the solvent evaporates.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
[0007]
In FIG. 1, reference numeral 1 denotes a spray gun body. A holder 2 is attached to the tip of the spray gun body, a gas bearing 3 is attached to the holder 2, and the gas bearing 3 is driven to rotate at high speed by an air turbine 9. A bell-shaped atomizing head 10 is attached to the tip of the shaft 7, and the liquid paint supplied through the hollow of the shaft 7 connects the inner surface of the atomizing head 10. After reaching the edge of the tip, it forms a mist by the action of centrifugal force and electrostatic field, and is applied to an object to be coated (not shown).
[0008]
The gas bearing 3 is attached to a bearing cylinder 5 in which pressurized air fed from a supply passage 4 formed in the spray gun body 1 is fitted with a shaft 7 and a narrow gap a as shown in an enlarged view in FIG. Pressurized air flows into the gap a from the numerous small holes 6 to support the shaft 7 in a floating state, and in the axial direction, it is applied in the same way from both sides of the flange 8 formed on the shaft 7. It is supported in a floating state by supplying pressurized air.
[0009]
The above is a conventionally known rotary atomizing paint spray gun, but in the present embodiment, it corresponds to the tip portion of the gas bearing 3 of the shaft 7 that rotates clockwise as viewed from the right side of FIGS. A left-twisted triangular mountain-shaped spiral groove 11 is formed in the portion to be formed.
[0010]
Therefore, when the tip of the spray gun is immersed in a solvent at the end of the painting operation and the atomizing head 10 is rotated at a low speed, the gas bearing 3 is positioned outside the gas bearing 3 (on the left side in FIGS. 1 and 2). It is possible to prevent the solvent mixed with the paint from entering the gap a by generating a flowing air flow.
[0011]
For this reason, it can prevent reliably that a coating material hardens | cures after a solvent evaporates, and obstructs rotation of the shaft 7. FIG.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional view of the main part.
[Explanation of symbols]
3: Gas bearing 5: Bearing cylinder 6: Small hole 7: Shaft 9: Air turbine 10: Atomizing head 11: Spiral groove a: Gap

Claims (1)

In a rotary atomizing coating spray gun in which paint is atomized and discharged by centrifugal force from an atomizing head attached to a shaft that is supported by a gas bearing and rotates at a high speed, the outer peripheral surface of the shaft A rotary atomization type in which a spiral groove twisted in a direction in which a gas flow toward the outside of the gas bearing is generated in a gap with the bearing cylinder by rotation in the same direction as that at the time of painting is formed in a portion corresponding to the tip of the gas bearing Spray gun for painting.

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