Method of coating lubrication paint on disk-shaped substrate

1. A method of coating a lubrication paint on a disk-shaped substrate, comprising:

applying a lubrication paint on a sliding portion of a disk-shaped substrate from a paint supply nozzle while rotating the disk-shaped substrate in the horizontal plane; and

leveling the lubrication paint applied on the sliding portion by contacting the lubrication paint with a doctor knife arranged at a downstream position in the direction of rotation of the disk-shaped substrate.

2. The method of claim 1 , wherein, if a line which intersects a plane including an edge line of the doctor knife and is perpendicular to the surface of disk-shaped substrate and a surface of the disk-shaped substrate is defined as the straight line (L 1 ), and a straight line connecting the center point (O) of the disk-shaped substrate and a point (P) where an inner edge of the sliding portion of the disk-shaped substrate cross the straight line (L 1 ) is defined as the straight line (L 2 ), the angle (θ 1 ) formed by the straight line (L 1 ) and the straight line (L 2 ), is −1° to +15°, wherein a negative angle means that the straight line (L 1 ) is at the upstream side of the rotation of the disk-shaped substrate from the straight line (L 2 ), and wherein a positive angle means that the straight line (L 1 ) is at the downstream side of the rotation of the disk-shaped substrate from the straight line (L 2 ).

3. The method of coating the lubrication paint on the disk-shaped substrate according to claim 2 , wherein a vertical angle (θ 2 ), which is the blade angle of the doctor knife ( 3 ) against the surface of the disk-shaped substrate, is −1° to +1°, wherein a negative angle means that the edge line of the doctor knife ( 3 ) has downward tilt from the inside to the outside of the disk-shaped substrate ( 1 ), and wherein a positive angle means that the edge line of the doctor knife ( 3 ) has upward tilt from the inside to the outside of the disk-shaped substrate ( 1 ).

4. The method of claim 1 , wherein a vertical angle (θ 2 ), which is the blade angle of the doctor knife ( 3 ) against the surface of the disk-shaped substrate is −1° to +1°, wherein a negative angle means that the edge line of the doctor knife ( 3 ) has downward tilt from the inside to the outside of the disk-shaped substrate ( 1 ), and wherein a positive angle means that the edge line of the doctor knife ( 3 ) has upward tilt from the inside to the outside of the disk-shaped substrate ( 1 ).

5. The method of coating the lubrication paint on the disk-shaped substrate according to claim 4 , wherein, if a straight line on the surface of the disk-shaped substrate ( 1 ) which passes point (P) where the inner edge of the sliding portion of the disk-shaped substrate crosses with straight line (L 1 ) and perpendicular to the straight line (L 2 ) is defined as the straight line (L 3 ), and a line intersecting a plane including the straight line (L 3 ) and perpendicular to the disk-shaped substrate ( 1 ) and the plane of the doctor knife ( 3 ) is defined as the straight line (L 4 ), an angle (θ 3 ) is formed by the straight line L 3 and the straight line (L 4 ) and is 25° to 85°.

6. The method of claim 1 , wherein if a straight line on the surface of the disk-shaped substrate 1 which passes point (P) where the inner edge of the sliding portion of the disk-shaped substrate crosses with straight line (L 1 ) and perpendicular to straight line (L 2 ) is defined as the straight line (L 3 ), and a line intersecting a plane including the straight line (L 3 ) and perpendicular to the disk-shaped substrate ( 1 ) and the plane of the doctor knife ( 3 ) is defined as the straight line (L 4 ), an angle (θ 3 ) is formed by the straight line L 3 and the straight line (L 4 ) is 25° to 85°.

7. The method of claim 6 , wherein two paint supply nozzles, an outer nozzle and an inner nozzle, are arranged along a radial direction of the disk-shaped substrate, and the position of the outer nozzle is 0.5 mm to 6 mm from the outer edge of the disk-shaped substrate and the pitch between the outer nozzle and the inner nozzle is 0.5 mm to 5 mm.

8. The method of claim 1 , wherein an outer nozzle and an inner nozzle are arranged along a radial direction of the disk-shaped substrate, and the position of the outer nozzle if 0.5 mm to 6 mm from the outer edge of the disk-shaped substrate and the pitch between the outer nozzle and the inner nozzle is 0.5 mm to 5 mm.

9. The method of claim 8 , wherein the inner diameter of the paint supply nozzle is 0.3 mm to 4 mm.

10. The method of claim 1 , wherein the inner diameter of the paint supply nozzle is 0.3 mm to 4 mm.

11. The method of claim 10 , wherein the viscosity of the lubrication paint is 1,000 mPa·s at 25° C. to 30,000 mPa·s at 25° C.

12. The method of claim 1 , wherein the viscosity of the lubrication paint is 1,000 mPa·s at 25° C. to 30,000 mPa·s at 25° C.

13. The method of claim 12 , wherein an amount of the paint coated on the sliding portion of the disk-shaped substrate is 0.006 g/cm 2 to 0.038 g/cm 2 per unit area of the sliding portion.

14. The method of claim 1 , wherein an amount of the paint coated on the sliding portion of the disk-shaped substrate is 0.006 g/cm 2 to 0.038 g/cm 2 per unit area of the sliding portion.

15. The method of claim 14 , wherein,

after finishing one cycle of the coating step, the doctor knife moves away from a position occupied during coating toward an upper direction, an outside direction and a frontward direction, at a speed of 0.1 mm to 10 mm/second; and

a rotation of the disk-shaped substrate during the moving away of the doctor knife is 10 rpm to 200 rpm.

16. The method of claim 1 , wherein,

after finishing one cycle of the coating step, the doctor knife moves away from a position occupied during coating toward an upper direction, an outside direction, and a frontward direction, at a speed of 0.1 mm to 10 mm/second; and

a rotation of the disk-shaped substrate during the moving away of the doctor knife is 10 rpm to 200 rpm.

17. The method of claim 16 , wherein the disk-shaped substrate is a swash plate of a swash-plate compressor which slides a shoe on the swash plate and converts a rotation of the swash plate into a reciprocating movement of a piston through the shoe to compress a coolant.

18. The method of claim 1 , wherein the disk-shaped substrate is a swash plate of a swash-plate compressor which slides a shoe on the swash plate and converts a rotation of the swash plate into a reciprocating movement of a piston through the shoe to compress a coolant.