Coating method

Abstract

Provided is a coating method capable of causing a coating material to easily adhere to pointed ends of center members.　This coating method is a method for coating, with the coating material, the center members of subjects to be coated. This coating method includes a pointed end coating step in which a rotary shaft (C) of a coating tank (25) is inclined with respect to the vertical direction, the rotation direction of a rotary disk (38A) is configured to be opposite to the rotation direction of a drum (28A), the rotary disk (38A) and the drum (28A) are rotated in such a manner that the rotation speed of the rotary disk (38A) is higher than the rotation speed of the drum (28A) so as to thereby cause, on a center member group (CG) formed from the plurality of center members, a first circulating flow movement in the form of a vortex flow around the axis of the coating tank (25) and a second circulating flow movement in the form of a vertical spiral flow that is lifted forward in the rotation direction and that subsequently falls due to its own weight, and the coating material is added to a merging portion of these flow movements so as to coat at least the pointed ends of the center members.

Claims

1. A coating method for coating a center to be coated with a coating material using a coating apparatus comprising a coating tank having a rotatable cylindrical drum and a rotating disk coaxially positioned at the lower end of the drum, the method comprising a first rotation step of inclining the rotation axis of the coating tank with respect to the vertical, setting the rotation direction of the rotating disk to be opposite to the rotation direction of the drum, and rotating the rotating disk and the drum such that the rotation speed of the rotating disk is greater than the rotation speed of the drum, thereby generating a first swirling circulating flow around the axis of the coating tank and a second swirling circulating flow that is lifted forward in the rotation direction and then falls by its own weight in a group of centers consisting of a plurality of centers, and adding the coating material to the confluence of these flows to coat at least the tip of the center.

2. The coating method according to claim 1, further comprising a second rotation step after the first rotation step, in which the rotation axis of the coating tank is directed vertically, the rotating disk is rotated, the coating material is added to the coating tank, and the entire center is coated.

3. The coating method according to claim 2, wherein the rotational speed of the rotating disk in the second rotation step is greater than the rotational speed of the rotating disk in the first rotation step.

4. The coating method according to claim 2 or 3, wherein in the second rotation step, the drum is rotated in a direction opposite to the rotation direction of the rotating disk.

5. The coating method according to claim 2 or 3, further comprising a third rotation step, after the second rotation step, in which the rotation axis of the coating tank is oriented vertically, and the rotating disk is rotated at a rotation speed greater than the rotation speed of the rotating disk in the second rotation step.

6. The coating method according to claim 2 or 3, further comprising a fourth rotation step, after the second rotation step, in which the rotating disk is rotated while alternatingly introducing hot air and cold air into the drum, with the rotation axis of the coating tank oriented vertically.

7. The coating method according to claim 5, further comprising a fifth rotation step after the third rotation step, inclining the rotation axis of the coating tank with respect to the vertical, and rotating the rotating disk and the drum in the same rotation direction and at the same rotational speed.

8. The coating method according to claim 1, further comprising a sixth rotation step in which, after coating the entire center including its tip in the first rotation step, the rotation axis of the coating tank is directed vertically and the rotating disk is rotated at a rotation speed greater than the rotation speed of the rotating disk in the first rotation step.

9. The coating method according to claim 8, further comprising a seventh rotation step, after the sixth rotation step, in which the rotating disk is rotated while alternatingly introducing hot air and cold air into the drum, with the rotation axis of the coating tank oriented vertically.

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