Sliding component for internal combustion engine and method of manufacturing sliding component for internal combustion engine

1. A sliding component for an internal combustion engine comprising:

a sliding component main body that includes a plurality of concave portions formed in a predetermined portion thereof; and

a coating layer that covers a portion of the sliding component main body, in which the plurality of concave portions are not formed,

wherein the coating layer is provided in a portion of the sliding component main body, which corresponds to the plurality of concave portions, and the coating layer includes a plurality of hole portions which allow the surfaces of the plurality of concave portions to be exposed therethrough, respectively, and

wherein an inner circumferential surface of the hole portion of the coating layer and an opening end edge of the concave portion of the sliding component main body have respective concentric circular shapes when seen in a direction in which a center line of the hole portion extends.

2. The sliding component for an internal combustion engine according to claim 1 ,

wherein an oil reservoir is formed by both of the hole portion of the coating layer and the concave portion of the sliding component main body.

3. The sliding component for an internal combustion engine according to claim 1 ,

wherein the inner circumferential surface of the hole portion of the coating layer has an inner diameter greater than that of the opening end edge of the concave portion of the sliding component main body.

4. The sliding component for an internal combustion engine according to claim 1 ,

wherein the plurality of hole portions of the coating layer and the plurality of concave portions of the sliding component main body are disposed in a predetermined pattern.

5. The sliding component for an internal combustion engine according to claim 1 ,

wherein an outer surface of the coating layer is a flat surface, in which the hole portions are not formed.

6. The sliding component for an internal combustion engine according to claim 1 ,

wherein a gap between the adjacent concave portions is greater than an opening width of the opening end edge of the concave portion.

7. The sliding component for an internal combustion engine according to claim 1 ,

wherein the coating layer is made of resin.

8. The sliding component for an internal combustion engine according to claim 1 , wherein

the sliding component main body includes a piston main body, and

the predetermined portion of the sliding component main body includes at least a sliding portion of the piston main body.

9. The sliding component for an internal combustion engine according to claim 1 ,

wherein the coating layer is respectively provided in portions corresponding to the plurality of concave portions, and includes the plurality of hole portions which allow the surfaces of the plurality of concave portions to be exposed therethrough, respectively, and a gap between the adjacent hole portions is greater than the opening width of the opening end edge of the concave portion.

10. A method of manufacturing a sliding component for an internal combustion engine comprising:

preparing a sliding component main body;

forming a coating layer on a predetermined surface of the sliding component main body; and

forming a plurality of hole portions in the coating layer through a laser ablation process in which a laser beam having an ultrashort pulse is applied to the coating layer under predetermined laser beam application conditions, and forming a plurality of concave portions in portions of the sliding component main body, which correspond to the plurality of hole portions, respectively,

wherein the plurality of hole portions are formed so that inner circumferential surfaces of the hole portions of the coating layer and an opening end edge of the concave portions of the sliding component main body have respective concentric circular shapes when seen in a direction in which a center line of the hole portions extend.