Bearing interface with recesses to reduce friction

摘要

A machine 101 having a bearing interface with recesses to reduce friction is provided. The machine 101 comprises a piston cylinder 103 and one or more piston rings 107 that are configured to move relative to the piston cylinder 103 during operation of the machine 101. The piston cylinder 103 comprises an inner surface 105 configured to engage at least a portion of a circumferential surface of each piston ring 107 thereby defining a contact zone 111 between the inner surface 105 of the cylinder 103 and the circumferential surface of each piston ring 107, the inner surface of the cylinder having at least one recess 129 indented into the inner surface 105 of the cylinder 103. The dimension of the recess 129 in the direction of movement of the piston rings 107 relative to the piston cylinder 103 is less than the dimension of the contact zone 111 in the direction of movement of the piston rings 107. One of the piston rings 107 is a top piston ring and the inner surface 105 of the cylinder 103 comprises: a top region 119 having a plurality of the recesses129 indented into the inner surface 105, the top region 119 extends towards the bottom end of the cylinder 103 away from the contact zone 111 between the top piston ring and the inner surface 105 when the piston 109 is at top dead centre of a stroke. The top region 119 is offset from the contact zone 111 between the top piston ring and the inner surface 105 when the piston 109 is at top dead centre of a stroke.