Piston ring combination
AssigneeTpr Co., Ltd.
InventorTetsuya Nango
Life of this patent
Estimating the term…
Abstract
In this piston ring combination, a second outer peripheral surface, which is the outer peripheral surface of a second ring, has a second protruding surface curved into a convex shape, and a pair of third outer peripheral surfaces, which are the outer peripheral surfaces of a pair of segments, each have a third outer peripheral area in which a third protruding surface is formed, the third protruding surfaces being curved into convex shapes. In at least one of the pair of third outer peripheral surfaces, the peripheral edge on a crank-chamber side is positioned farther outward in the diametrical direction than the peripheral edge on a combustion-chamber side, and a peak of the third protruding surface is positioned nearer to the crank chamber than the center of the third outer peripheral surface.
Claims20
A piston ring combination including a top ring, a second ring, and an oil ring that are mounted in ring grooves formed on a piston of an internal combustion engine to reduce aggressiveness toward a cylinder inner wall during an initial stage of operation of the internal combustion engine, wherein
- a first outer peripheral surface that is an outer peripheral surface of the top ring includes a first outer peripheral region where a first protruding surface is formed, the first protruding surface being curved outward into a convex shape in a radial direction of the top ring in a cross-section perpendicular to a circumferential direction of the top ring, the convex shape having a peak at an outermost position of the first outer peripheral surface in the radial direction of the top ring,
- a second outer peripheral surface that is an outer peripheral surface of the second ring includes a second outer peripheral region where a second protruding surface is formed, the second protruding surface being curved outward into a convex shape in a radial direction of the second ring in a cross-section perpendicular to a circumferential direction of the second ring, the convex shape having a peak at an outermost position of the second outer peripheral surface in the radial direction of the second ring,
- the oil ring includes a pair of segments, each provided on a corresponding side in an axial direction, and an expander-spacer that biases the pair of segments outward in a radial direction,
- a pair of third outer peripheral surfaces that are outer peripheral surfaces of the pair of segments each include a third outer peripheral region where a third protruding surface is formed, the third protruding surface being curved outward into a convex shape in the radial direction of the oil ring in a cross-section perpendicular to a circumferential direction of the oil ring, the convex shape having a peak at an outermost position of the third outer peripheral surface in the radial direction of the oil ring, and
- in relation to at least one of the pair of third outer peripheral surfaces, a peripheral edge of the third outer peripheral region on a crankcase side is positioned more outward in the radial direction than a peripheral edge on a combustion chamber side, and the peak of the third protruding surface is positioned closer to a crankcase than a center of the third outer peripheral surface in the axial direction of the oil ring.
A piston ring combination including a top ring, a second ring, and an oil ring that are mounted in ring grooves formed on a piston of an internal combustion engine to reduce aggressiveness toward a cylinder inner wall during an initial stage of operation of the internal combustion engine, wherein
- a first outer peripheral surface that is an outer peripheral surface of the top ring includes a first outer peripheral region where a first protruding surface is formed, the first protruding surface being curved outward into a convex shape in a radial direction of the top ring in a cross-section perpendicular to a circumferential direction of the top ring, the convex shape having a peak at an outermost position of the first outer peripheral surface in the radial direction of the top ring,
- a second outer peripheral surface that is an outer peripheral surface of the second ring includes a second outer peripheral region where a second protruding surface is formed, the second protruding surface being curved outward into a convex shape in a radial direction of the second ring in a cross-section perpendicular to a circumferential direction of the second ring, the convex shape having a peak at an outermost position of the second outer peripheral surface in the radial direction of the second ring,
- the oil ring includes a ring main body including a pair of rails, each on a corresponding side in an axial direction, and a coil expander that biases the ring main body outward in a radial direction,
- a pair of third outer peripheral surfaces that are outer peripheral surfaces of the pair of rails each include a third outer peripheral region where a third protruding surface is formed, the third protruding surface being curved outward into a convex shape in the radial direction of the oil ring in a cross-section perpendicular to a circumferential direction of the oil ring, the convex shape having a peak at an outermost position of the third outer peripheral surface in the radial direction of the oil ring, and
- in relation to at least one of the pair of third outer peripheral surfaces, a peripheral edge of the third outer peripheral region on a crankcase side is positioned more outward in the radial direction than a peripheral edge on a combustion chamber side, and the peak of the third protruding surface is positioned closer to a crankcase than a center of the third outer peripheral surface in the axial direction of the oil ring.
Dependencies are inferred from the claim text.