Electrostatic atomizing coating apparatus and coating method

Patent metadata

Field	Value
Publication number	US-2017056901-A1
Application number	US-201615235543-A
Country	US
Kind code	A1
Filing date	Aug 12, 2016
Priority date	Aug 28, 2015
Publication date	Mar 2, 2017
Grant date	—

Abstract

An electrostatic atomizing coating apparatus and method incorporate a rotary head having a base portion, an open end and a plurality of grooves formed radially on an inner peripheral surface of the open end, an inside diameter of the rotary head increasing from the base portion toward the open end, and a motor configured to rotate the rotary head to discharge a thread-shaped paint. A voltage is applied to the rotary head so as to form an electrostatic field between the open end of the rotary head and an earthed coating target and to electrostatically atomize the thread-shaped paint discharged from the open end. Voltage output from the generator is controlled so as to adjust an intensity of the electrostatic field and to control a particle diameter of the electrostatically atomized thread-shaped paint.

First claim

What is claimed is:

1 . An electrostatic atomizing coating apparatus comprising:
at least one rotary head having a base portion, an open end and a plurality of grooves formed radially on an inner peripheral surface of the open end, an inside diameter of the rotary head increasing from the base portion toward the open end; a motor configured to rotate the at least one rotary head to discharge a thread-shaped paint from the open end; a generator configured to provide a voltage to the at least one rotary head so as to form an electrostatic field between the open end and a grounded coating target and electrostatically atomize the thread-shaped paint discharged from the open end; and a controller configured to control a voltage output from the generator so as to adjust an intensity of the electrostatic field and control a particle diameter of the electrostatically atomized thread-shaped paint.

2 . The electrostatic atomizing coating apparatus according to claim 1 , wherein the controller controls the voltage output from the generator so that a value of a current discharged from the open end becomes constant.

3 . The electrostatic atomizing coating apparatus according to claim 1 , wherein an outer peripheral surface of the at least one rotary head has a circular column shape.

4 . The electrostatic atomizing coating apparatus according to claim 1 , further comprising an outer ring configured to surround an outer peripheral surface of the at least one rotary head,
wherein the voltage output from the generator is provided to the outer ring.

5 . The electrostatic atomizing coating apparatus according to claim 4 , wherein the outer ring comprises a base and a front end.

6 . The electrostatic atomizing coating apparatus according to claim 5 , wherein a sectional area of the outer ring perpendicular to an axial direction of the outer ring decreases from the base of the outer ring toward the front end.

7 . The electrostatic atomizing coating apparatus according to claim 6 , wherein a thickness of the front end is in the range of 0.3 mm to 1 mm.

8 . The electrostatic atomizing coating apparatus according to claim 5 , wherein a plurality of grooves are formed on an outer peripheral surface of the front end along the axial direction of the outer ring.

9 . The electrostatic atomizing coating apparatus according to claim 5 , wherein the outer ring further comprises a plurality of protruding potions projecting from the front end along the axial direction of the outer ring.

10 . The electrostatic atomizing coating apparatus according to claim 1 , wherein the apparatus comprises a plurality of rotary heads, and
the plurality of rotary heads are provided in parallel with each other.

11 . The electrostatic atomizing coating apparatus according to claim 1 , wherein an outside diameter of the at least one rotary head is in the range of 20 mm to 50 mm.

12 . The electrostatic atomizing coating apparatus according to claim 1 , wherein a number of the plurality of grooves is in the range of 600 to 1,000.

13 . The electrostatic atomizing coating apparatus according to claim 1 , wherein the particle diameter of the electrostatically atomized thread-shaped paint is in the range of 20 μm to 30 μm in terms of Sauter Mean Diameter.

14 . The electrostatic atomizing coating apparatus according to claim 1 , wherein the motor rotates the at least one rotary head at a speed in the range of 500 mm/s to 1,200 mm/s.

15 . An electrostatic atomizing coating method comprising:
discharging a thread-shaped paint from an open end of a rotary head by rotating the rotary head, the rotary head having a base portion and a plurality of grooves formed radially on an inner peripheral surface of the open end, an inside diameter of the rotary head increasing from the base portion toward the open end; electrostatically atomizing the thread-shaped paint discharged from the open end by forming an electrostatic field between the open end and a coating target; and adjusting an intensity of the electrostatic field to control a particle diameter of the electrostatically atomized thread-shaped paint.

Assignees

• Toyota Motor Co Ltd

Inventors

• Tani Shinji
• Nabeshima Astuo
• Kondo Takahito

Classifications

• B05D1/06

  Applying particulate materials · CPC title

• B05B5/0407

  with a spraying edge, e.g. like a cup or a bell · CPC title

• B05C19/04

  the particulate material being projected, poured or allowed to flow onto the surface of the work (B05C19/02 takes precedence; involving spraying or electrostatic projection B05B ){(B05C19/005 takes precedence)} · CPC title

• B05C11/1018

  responsive to distance of target · CPC title

• B05B5/0418

  designed for spraying particulate material · CPC title