Kabushiki Kaisha Riken

Toyota Jidosha Kabushiki Kaisha

Sumio Ono

Yoshiaki Wada

Hatsutaro Mizuno

Hitoshi Hattori

Yorishige Maeda

Hiroshi Miida

Ko Chiba

Shizuo Shinada

A steel oil ring assembly having an upper rail, a lower rail and an annular space-expander embraced by the rails and having radially extending or axially extending corrugations. The spacer is split at one circumferential location to form abutting end portions which come into pressured contact with each other at a force point located on a plane passing through the centers of the corrugations that extends in an axial direction for radially extending corrugations and in a radial direction for axially extending corrugations. The free ends of the abutting end portions of the spacer form an opening having an angle of 10.degree..+-.9.degree. extending outwardly from the force point.

Steel oil ring assembly

A combined oil ring assembly consisting of a corrugated, annular expander having abutting ends and a pair of upper and lower side rails, the rails resting on the upper and lower sides of the expander and engaging a plurality of circumferentially spaced ear portions formed on the two sides of the expander. To strengthen the ends of the expander, the ear portions of the expander nearest to its two abutting ends, only have cut-outs on their sides remote from the ends and nearest to the next adjacent ear portions.

Combined oil ring assembly

A combined oil ring assembly including an expander and a pair of side rails. The expander is formed in the shape of a plurality of corrugations having a plurality of oil releasing bores and cut-out portions. The circumferential lengths of the oil releasing bores in the expander that are located at least between the opposed ends of the expander and the ear portions nearest to the opposed ends as well as between the nearest ear portions and the next ear portions are shorter than that of the other oil releasing bores.

An oil-ring comprising a pair of side rails and an expander disposed between the side rails. The expander extends in a circumferential direction and has waves in a radial direction. At both sides of radially inner portions of the expander, side rail engaging portions protrude in an axial direction. The side rail engaging portions are formed as paired side rail engaging sections within one pitch of the waves, by defining a slit extending in the axial direction at a central portion of one side rail engaging portion. Due to the division from one side rail engaging portion to paired side rail engaging sections, the rigidity of each side rail engaging portion can be weakened appropriately, and each side rail can follow against the cylinder bore surface satisfactorily, thereby decreasing oil consumption.

Oil ring structure having reduced rigidity

The annular expander of a piston ring assembly with vertically extending notches each of which is formed on either side of a plurality of circumferentially spaced upstanding tabs projecting from the top and bottom edges of the expander. The tabs, which form the abutments for the inner peripheral edges of upper and lower annular side rails, the outer peripheral edges of which are in sliding contact with a cylinder wall, undergo elastic deformation made possible by the notches when the corresponding side rails are subjected to a strong force received from the cylinder wall owing to piston wobble during reciprocation. The elastic deformation of the tabs assures that the side rails will remain in contact with the cylinder wall at all times during the reciprocation of the piston.

Growing community of inventors

Kashiwazaki, Japan

Sumio Ono