초록 ▼

A coating method includes rotatably supporting both ends of the piston or product to be coated; injecting coating material to a first parts of the piston or product to be coated through a first nozzle while rotating the piston, and simultaneously spreading to a uniform film thickness the coating mat

A coating method includes rotatably supporting both ends of the piston or product to be coated; injecting coating material to a first parts of the piston or product to be coated through a first nozzle while rotating the piston, and simultaneously spreading to a uniform film thickness the coating material applied to the first part of the piston or product to be coated thereby removing excess coating material; fixedly supporting both ends of the piston or product to be coated; injecting coating material to a second pad of the piston or product to be coated through a second nozzle while sliding the second nozzle in an axial direction of the piston or product to be coated, and simultaneously spreading to a uniform film thickness the coating material applied to the second part of the piston or product to be coated thereby removing excess coating material.

대표청구항 ▼

What is claimed is: 1. A method of coating both head parts and a bridge part of a piston for a fixed displacement swash plate type compressor using a coating apparatus, said coating apparatus comprising: rotation support means for rotatably supporting both ends of the piston, a pair of first coatin

What is claimed is: 1. A method of coating both head parts and a bridge part of a piston for a fixed displacement swash plate type compressor using a coating apparatus, said coating apparatus comprising: rotation support means for rotatably supporting both ends of the piston, a pair of first coating material applying means installed above the rotation support means in a manner such that said pair of first coating material applying means can be moved upward and downward, the pair of first coating material applying means having a pair of first nozzles that include a pair of first coating material spreading means, respectively, fixing means installed in the vicinity of the rotation support means for fixedly supporting both ends of the piston, and second coating material applying means installed above the fixing means in a manner such that said second coating material applying means can be moved upward and downward and slid laterally, the second coating material applying means having a second nozzle that includes second coating material spreading means, the method comprising the steps of: rotatably supporting both ends of the piston by the rotation support means; lowering the pair of first coating material applying means so that the respective first coating material spreading means are placed adjacent to both head parts of the piston; injecting coating material to the head parts of the piston through the first nozzles while rotating the piston by the rotation support means, and simultaneously spreading, by the first coating material spreading means, to a uniform film thickness the coating material applied to the head parts of the piston thereby removing excess coating material; fixedly supporting both ends of the piston by the fixing means; lowering the second coating material applying means so that the second coating material spreading means are placed adjacent to the bridge part of the piston; and injecting coating material to the bridge part of the piston through the second nozzle while sliding the second coating material applying means in an axial direction of the piston, and simultaneously spreading, by the second coating material spreading means, to a uniform film thickness the coating material applied to the bridge part of the piston thereby removing excess coating material; wherein a first viscosity of the coating material applied to the head parts is greater than a second viscosity of the coating material applied to the bridge part. 2. The method as set forth in claim 1, wherein the second coating material applying means have a guide post which extends downward beyond the second coating material spreading means to be brought into sliding contact with the bridge part of the piston; and in the step of lowering the second coating material applying means, as a lower end of the guide post comes into contact with the bridge part, a predetermined gap is defined between lower ends of the second coating material spreading means and the bridge part of the piston thereby defining the film thickness of the coating material coated on the bridge part. 3. The method as set forth in claim 1, wherein, during the coating of the head parts of the piston being rotated by the rotation support means, an initial rotational velocity of the piston measured in the first revolution thereof is different from a subsequent rotational velocity of the piston. 4. The method as set forth in claim 3, wherein the initial rotational velocity of the piston measured in the first revolution is set to be lower than the subsequent rotational velocity of the piston. 5. The method as set forth in claim 4, wherein a starting velocity of the piston at the beginning of the first revolution is different from an ending velocity of the piston at the end of said first revolution. 6. The method as set forth in claim 1, wherein, during the coating of the bridge part of the piston, beginning from the time that the coating material is injected, a sliding speed of the second coating material applying means is varied by stages. 7. The method as set forth in claim 6, wherein the sliding speed of the second coating material applying means is set to a higher value at an initial stage, to a lower value at an intermediate stage, and back again to a higher value at a final stage. 8. A method of coating a head part and both wing parts of a piston for a variable displacement swash plate type compressor using a coating apparatus, said coating apparatus comprising: rotation support means for rotatably supporting both ends of the piston; first coating material applying means installed above the rotation support means in a manner such that said first coating material applying means can be moved upward and downward, the first coating material applying means having a first nozzle that includes first coating material spreading means; fixing means installed in the vicinity of the rotation support means for fixedly supporting both ends of the piston; and second coating material applying means installed above the fixing means in a manner such that said second coating material applying means can be moved upward and downward and slid laterally, the second coating material applying means having a second nozzle that includes second coating material spreading means, the method comprising the steps of: rotatably supporting both ends of the piston by the rotation support means; lowering the first coating material applying means so that the first coating material spreading means are placed adjacent to the head part of the piston; injecting coating material to the head part of the piston through the first nozzle while rotating the piston by the rotation support means, and simultaneously spreading, by the first coating material spreading means, to a uniform film thickness the coating material applied to the head part of the piston thereby removing excess coating material; fixedly supporting both ends of the piston by the fixing means; lowering the second coating material applying means so that the second coating material spreading means are placed adjacent to both wing parts of the piston; and injecting coating material to the wing parts of the piston through the second nozzle while sliding the second coating material applying means in an axial direction of the piston, and simultaneously spreading, by the second coating material spreading means, to a uniform film thickness the coating material applied to the wing parts of the piston thereby removing excess coating material; wherein a viscosity of the coating material applied to the wing parts is the same as or lower than that of the coating material applied to the head part. 9. The method as set forth in claim 8, wherein the second coating material applying means have a guide post which extends downward beyond the second coating material spreading means to be brought into sliding contact with a bridge part of the piston; and in the step of lowering the second coating material applying means, as a lower end of the guide post comes into contact with the bridge part, a predetermined gap is defined between lower ends of the second coating material spreading means and the wing parts thereby defining the film thickness of the coating material coated on the wing parts. 10. The method as set forth in claim 8, wherein, during the coating of the head part of the piston being rotated by the rotation support means, an initial rotational velocity of the piston measured in the first revolution thereof is different from a subsequent rotational velocity of the piston. 11. The method as set forth in claim 10, wherein the initial rotational velocity of the piston measured in the first revolution is set to be lower than the subsequent rotational velocity of the piston. 12. The method as set forth in claim 11, wherein a starting velocity of the piston at the beginning of the first revolution is different from an ending velocity of the piston at the end of said first revolution. 13. The method as set forth in claim 8, wherein, during the coating of the wing parts of the piston, beginning from the time that the coating material is injected, a sliding speed of the second coating material applying means is varied by stages. 14. The method as set forth in claim 13, wherein the sliding speed of the second coating material applying means is set to a higher value at an initial stage, to a lower value at an intermediate stage, and back again to a higher value at a final stage. 15. The method as set forth in claim 8, wherein the viscosity of the coating material applied to the wing parts is lower than that of the coating material applied to the head part. 16. A method of coating both head parts and two pairs of wing parts of a half-finished product, which comprises a pair of attached pistons and which is prepared in the course of manufacturing pistons for variable displacement swash plate type compressors prior to being cut into two pistons, using a coating apparatus, said coating apparatus comprising: rotation support means for rotatably supporting both ends of the half-finished product; first, second and third coating material applying means; fixing means installed in the vicinity of the rotation support means for fixedly supporting both ends of the half-finished product; said first and third coating material applying means being installed above the rotation support means in a manner such that said first and third coating material applying means can be moved upward and downward, the first and third coating material applying means respectively having first and third nozzles that include first and third coating material spreading means, respectively; and said second coating material applying means being installed above the fixing means in a manner such that said second coating material applying means can be moved upward and downward and slid laterally, the second coating material applying means having a second nozzle that includes second coating material spreading means; the method comprising the steps of: rotatably supporting both ends of the half-finished product by the rotation support means; lowering the first and third coating material applying means so that the first and third coating material spreading means are placed adjacent to the head parts of the half-finished product; injecting coating material to the head parts of the half-finished product through the first and third nozzles while rotating the half-finished product, and simultaneously spreading, by the first and third coating material spreading means, to a uniform film thickness the coating material applied to the head parts of the half-finished product thereby removing excess coating material; fixedly supporting both ends of the half-finished product by the fixing means; lowering the second coating material applying means so that the second coating material spreading means are placed adjacent to the two pairs of wing parts of the half-finished product supported by the fixing means in a state where the two pairs of wing parts are positioned at a center portion of the half-finished product and have not been separated from each other; and injecting coating material to the wing parts of the half-finished product through the second nozzle while sliding the second coating material applying means in an axial direction of the half-finished product, and simultaneously spreading, by the second coating material spreading means, to a uniform film thickness the coating material applied to the wing parts of the half-finished product thereby removing excess coating material; wherein a viscosity of the coating material applied to the wing parts is the same as or lower than that of the coating material applied to the head parts. 17. The method as set forth in claim 16, wherein the second coating material applying means have a guide post which extends downward beyond the second coating material spreading means to be brought into sliding contact with a bridge part of the half-finished product; and in the step of lowering the second coating material applying means, as a lower end of the guide post comes into contact with the bridge part of the half-finished product, a predetermined gap is defined between lower ends of the second coating material spreading means and the wing parts thereby defining the film thickness of the coating material coated on the wing parts. 18. The method as set forth in claim 16, wherein, during the coating of the head parts of the half-finished product being rotated by the rotation support means, an initial rotational velocity of the half-finished product measured in the first revolution thereof is different from a subsequent rotational velocity of the half-finished product. 19. The method as set forth in claim 18, wherein the initial rotational velocity of the half-finished product measured in the first revolution is set to be lower than the subsequent rotational velocity of the half-finished product. 20. The method as set forth in claim 19, wherein a starting velocity of the half-finished product at the beginning of the first revolution is different from an ending velocity of the half-finished product at the end of said first revolution. 21. The method as set forth in claim 16, wherein, during the coating of the wing parts of the half-finished product, beginning from the time that the coating material is injected, a sliding speed of the second coating material applying means is varied by stages. 22. The method as set forth in claim 21, wherein the sliding speed of the second coating material applying means is set to a higher value at an initial stage, to a lower value at an intermediate stage, and back again to a higher value at a final stage. 23. The method as set forth in claim 19, wherein the viscosity of the coating material applied to the wing parts is lower than that of the coating material applied to the head parts.