A valve assembly includes a valve body defining a cylindrical passage therein about an axis. An inlet port is defined in or near a first end of the valve body. First and second outlet ports are defined in the valve body extending radially outward from the cylindrical passage. A cylindrical valve spool having a central passage is positioned within, and sealingly engaged with, the cylindrical passage. The valve spool is moveable along the axis among: a first position wherein the inlet port is in fluid communication with the first outlet port but not the second outlet port, a second position wherein the inlet port is in fluid communication with the second outlet port but not the first outlet port, and an intermediate position between the first and second positions wherein the inlet port is in fluid communication with both of the first and second outlet ports.

Provided is a combined oil ring that further reduces engine oil consumption. A combined oil ring attached to an oil ring groove of a piston includes: a pair of upper and lower side rails each formed into a flat annular shape, and having a slide contact part that comes into sliding contact with a cylinder; and a spacer expander arranged between the pair of upper and lower side rails. In at least the upper side rail of the pair of upper and lower side rails, a cross-sectional shape of the slide contact part along an axial direction of the piston is a tapered shape linearly spreading from upper to lower parts of the piston; the tapered shape is at an angle of 5 to 30 degrees with respect to a central axis of the spacer expander, and has a vertex of the tapered shape within 0.15 mm from a lower end of the side rail; and a part closer to the lower end than the vertex is formed into a curved shape having a curvature of R0.01 to 0.5.

A combined piston structure for a compressor includes a first piston ring, a second piston ring, an expandable ring, a guide ring, and a piston. A side of the first piston ring has a slit defined as a first cut. An upper end of an outer surface of the first piston ring is provided with an annular protruding portion. A side of the second piston ring has a slit defined as a second cut. A side of the expandable ring has a slit defined as a third cut. The guide ring is annular and made of a self-lubricating material having a low friction coefficient. A side of the guide ring has a V-shaped opening. An upper end of an outer surface of the piston is provided with an annular first groove. An annular second groove is disposed below the first groove.

The present invention relates to an oil scraper ring spring (1) for an oil scraper ring (3) comprising the oil scraper ring spring (1), an upper and a lower metal ring (21, 22) and provided for being mounted in an oil ring groove of a piston. The oil scraper ring spring (1) comprises a plurality of upper regions (5) and a plurality of lower regions (7) arranged in alternating manner in a circumferential direction so as to be spaced in an axial direction; connecting regions (9) each connecting the adjacent upper and lower regions (5, 7) to each other. Each of the upper and lower regions (5, 7) comprises: a nose section (13) disposed at the inner circumferential end and adapted to push the respectively abutting upper or lower metal ring (21, 22) radially outwardly, and having a through-opening (15); an abutment section (17) extending radially between the nose section (13) and the outer circumferential end and configured to have the respective upper metal ring (21) abutting thereon or the respective lower metal ring (22) abutting thereon; wherein the abutment section (17) has a recess (19) formed therein the depth of which, relative to the abutting area of the abutment section (17), increases in the radial direction towards the through-opening (15), and the width of which increases in the radial direction towards the through-opening (15); wherein the recess (19) in the abutment section (17) has substantially the shape of a half-funnel; wherein the half-funnel has an opening angle of 30 to 150, in particular of 30 to 60, or wherein the upper side edges of the recess (19) span an angular segment of 5-50, in particular 5-15; and wherein increasing the depth and width of the recess (19) radially inwardly together with the through-opening (15) serves to increase and accelerate the oil flow to the piston center.

A side rail (1) in a sprit ring shape is to be mounted on a space expander (2) and to constitute, together with the space expander (2), a multi-piece oil ring (3) used in an internal combustion engine. The side rail (1) includes an outer peripheral surface (14) facing radially outward, an inner peripheral surface (13) facing radially inward, a first axial surface (11) facing one end of an axial direction, and a second axial surface (12) facing the other end of the axial direction and parallel to the first axial surface (11). A bevelled portion (30) is provided between the outer peripheral surface (14) and the second axial surface (12) and formed in a tapered surface having a diameter gradually decreasing from a position on the outer peripheral surface (14) at 0.05 mm or more from the first axial surface (11) toward the second axial surface (12).

A side rail (1) is formed in a sprit ring shape with an opening (10) and to be mounted on a space expander (2) in an annular shape to constitute, together with the space expander (2), a multi-piece oil ring (3) used in an internal combustion engine. The side rail (1) includes an outer peripheral surface (14) facing radially outward, an inner peripheral surface (13) facing radially inward, a first axial surface (11) facing a crankcase, a second axial surface (12) facing a combustion chamber and parallel to the first axial surface (11), and a protrusion (20) formed on the outer peripheral surface (14) in a position offset from an intermediate position between the first axial surface (11) and the second axial surface (12) toward the first axial surface (11) and protruding radially outward from the outer peripheral surface (14).

Exemplary oil control rings and methods are disclosed. An oil control ring may include an upper lamella having a first outer radial surface and a lower lamella having a second outer radial surface. An expander ring is in communication with the upper lamella and the lower lamella and generates an expander radial outward force on the lamellas. At least one of the first outer radial surface and the second outer radial surface is comprised of a first contact section and a first tapered section. The first tapered section is configured to generate a first radially inward force greater than or equal to the expander radial outward force when moved in a first direction and a second radially inward force less than the expander radial outward force when moved in a second direction.

A combination of piston rings assembled to a piston of an internal combustion engine includes four compression rings. An outer peripheral surface of a first compression ring includes a barrel surface, an outer peripheral surface of a second compression ring includes an outer peripheral end portion and a taper surface, an outer peripheral surface of a third compression ring includes an outer peripheral end portion and a taper surface, and an outer peripheral surface of a fourth compression ring includes an outer peripheral end portion and a taper surface.

A combination of piston rings assembled to a piston of an internal combustion engine includes four compression rings. An outer peripheral surface of a first compression ring includes a barrel surface, an outer peripheral surface of a second compression ring includes an outer peripheral end portion and a taper surface, an outer peripheral surface of a third compression ring includes an outer peripheral end portion and a taper surface, and an outer peripheral surface of a fourth compression ring includes an outer peripheral end portion and a taper surface.

A side rail (1) in a sprit ring shape is to be mounted on a space expander (2) and to constitute, together with the space expander (2), a multi-piece oil ring (3) used in an internal combustion engine. The side rail (1) includes an outer peripheral surface (14) facing radially outward, an inner peripheral surface (13) facing radially inward, a first axial surface (11) facing one end of an axial direction, and a second axial surface (12) facing the other end of the axial direction and parallel to the first axial surface (11). A bevelled portion (30) is provided between the outer peripheral surface (14) and the second axial surface (12) and formed in a tapered surface having a diameter gradually decreasing from a position on the outer peripheral surface (14) at 0.05 mm or more from the first axial surface (11) toward the second axial surface (12).