Piston for an internal combustion engine

Abstract

Disclosed is a piston for an internal combustion engine, which includes a land portion, and a skirt portion including a non-coated portion which is formed in an arbitrary shape on a sliding portion thereof and a coated portion which is formed on a sliding portion thereof other than the sliding portion on which the non-coated portion is formed. When the piston is descending, an oil which has adhered on a cylinder bore is introduced into the non-coated portion and accordingly an oil film is established in the non-coated portion. Since the advantageous effects of the coated portion and the oil film are combined in the piston, the sliding resistance can be reduced remarkably. Hence, the coated portion can be inhibited from wearing out, and its function of the sliding resistance reduction can be maintained for a long period of time. In addition, since the non-coated portion does not work as a sliding surface, there arises a reduced sliding surface area which also results in the reduction of the sliding resistance. The non-coated portion and the coated portion can be formed with a resin by printing. If such is the case, they can be formed with ease and at a less production cost.