| 摘要 |
<p>A piston, which reciprocates in a cylinder bore (23) of an engine (10), is supplied with lubricating oil. The piston includes pin bosses (13) provided under a piston head (12), a symmetrical pair of skirts (17), and side walls (18) connecting the pin bosses (13) and the skirts (17). The side walls (18) have openings (19), which communicate the outer side of the walls (18) with the inner side of the walls (18) under the middle section of the head (12). A recess (26) is defined in the lower surface (12a) of the head (12) to receive a spray of lubricating oil. The width (W1) of the recess (26) is wider than the width (D2) of each skirt (17) at its basal portion. This causes the oil supplied to the lower surface (12a) of the head (12) during movement of the piston to be injected against the recess (26) and thus be diffused. As a result, oil passes by the basal section of the skirts (17) and permeates into the space defined by the cylinder bore (23) and the skirts (17). <IMAGE></p> |
