Abstract: A composite seal ring has a resin seal ring and a metal spring. The resin seal ring is attached in an outer peripheral groove of a valve that opens and closes a passage by a rotational displacement, and the resin seal ring seals between an inner wall of a passage portion that forms the passage and the valve, in the fully closed state of the valve. A metal spring is circularly disposed within a radial width of the resin seal ring. The spring is configured to press the resin seal ring radially outwardly and radially inwardly due to the pressure acting on the resin seal ring or a deformation of the resin seal ring.

Abstract: There is provided a seal apparatus for sealing against a rod, comprising a double seal including a rod seal and an O-ring which serves as a back-up ring for the rod seal. The double seal is provided in an annular groove formed on an inner circumferential surface of a rod guide which guides a sliding motion of the rod. An annular partition wall extends from the rod guide so that a force applied to the rod seal from the O-ring is shared between the rod seal and the partition wall. An annular protrusion is formed on a front end surface of the partition wall, so that when the rod seal is pressed with a large force toward the low-pressure side, the protrusion bites into a stepped surface of the rod seal and a front end surface of the rod seal is brought into contact with a low-pressure-side seal-bearing surface of the rod guide. The force applied to the rod seal is distributed to two sites.

Abstract: A single-piece oil scraper piston ring includes a ring axis and first, second and third axially mutually spaced runner webs having a respective first, second and third runner face adapted to slidingly engage an engine cylinder wall during operation. The first and third runner webs flank the second runner web. A first connecting web couples the first runner web to the second runner web and a second connecting web couples the third runner web to the second runner web. First and second throughgoing oil outflow holes are provided in the first and second connecting webs, respectively. The piston ring further includes a first groove having a first side wall forming part of the first runner web and a second side wall; and a second groove axially spaced from the first groove and having a first side wall and a second side wall which forms part of the third runner web. First and second hose springs are received in the first and second grooves, respectively.

Abstract: The oil control ring 1 is provided to attach in an annular groove 10 formed in a piston 2 for internal combustion engine. The spacer expander 4 comprises a base 8, a plurality of supports 6 and a plurality of arms 7. The supports 6 and arms 7 are integrally formed with the base 8 to extend from an outer periphery 8a or inner periphery 8b of the base 8. The supports 6 resiliently urge a side rail 5 mounted on the space expander 4 toward an upper surface 14 of the annular groove 10 so that during upward stroke of the piston 2, the supports 6 can be resiliently deformed to form between the side rail 5 and upper surface 14 of the groove 10 a radial passage through which oil scraped by the side rail can be drained. Each arm 7 is provided with a lug 8 to resiliently urge the side rail 5 in radial and outward direction.