Abstract: A piston assembly having a piston and a piston ring. The ring mates to the piston in a groove on the outer surface of the piston. The ring includes two side walls that connect between inner and outer peripheral walls. The side walls converge outwardly at different angles from the inner peripheral wall to the outer peripheral wall. The angles are different to produce a twist feature of the ring within the piston groove to generate a better seal by the ring. The groove of the piston is generally tapered and has top and bottom walls converging at angles approximately equal to the angles of the side walls of the ring. A method of manufacturing the piston assembly includes forming first and second side walls having first and second angles by outwardly converging from the inner peripheral wall to the outer peripheral wall.

Abstract: A spring expander for oil control piston rings incorporates two spring mechanisms. One spring mechanism produces circumferentially directed hoop stress in the expander body when the expander body itself is contracted. A second radially acting spring mechanism is provided by circumferentially spaced spring fingers which radially deflect. Because the two spring mechanisms act together, the expander has a combined spring rate which is lower than the spring rate of either the circumferential spring mechanism or the spring rate of the radial spring mechanism. The expander also has expansion stops which limit the radial expansion of the spring fingers, and thereby limit the expansion of the associated rail ring to reduce pop-out during assembly. Contraction stops limit radial contraction of the rail ring with respect to the expander and maintain a clearance between the expander and the cylinder wall.

Abstract: A non-elastomeric sensor holding fixture using metal-to-sensor contact friction in a wheel slip control system maintains a wheel speed sensor in intimate contact with an exciter wheel without the excessive sensor wear which otherwise happens when the wheel speed sensor is held in place with resilient elastomeric holder. The use of metal-to-sensor frictional contact in the holding fixture avoids the hardening and seizing normally occurring in elastomeric-to-sensor frictional contact due to time and allows readjustment of sensor position after extended use.