Kabushiki Kaisha Riken

Hiroyuki Yabune

Hiroshi Shimizu

Masaaki Fujita

Hiroyuki Sugihara

Yoshiyuki Hirade

Kentaro Miyagawa

A side rail forms an oil control ring together with a spacer expander, and includes: an outer peripheral surface; an inner peripheral surface having a vertically symmetrical shape in an axial cross section; a first side surface; and a second side surface. The inner peripheral surface includes an inner tip portion satisfying following Condition 1 in an axial cross section.0.7≤1/0≤1.1  Condition 1: In the expression, R1 represents a curvature radius (unit: mm) of a curve forming the inner tip portion, and h0 represents a height (unit: mm) of the side rail.

Side rail and oil control ring comprising same

To provide a combined oil control ring comprising a pair of upper and lower side rails and an axially corrugated spacer expander having upper and lower portions for automobile engines, which is capable of keeping an excellent oil-controlling function without sticking between a spacer expander and side rails even in a long period of engine operation, the upper and lower portions of the spacer expander have tabs pushing inner peripheral surfaces of the side rails, projections supporting the side rails, and intermediate portions between the tabs and the projections; each intermediate portion opposing the side rail has at least one groove extending in a substantially circumferential direction is recessed when viewed along a radial direction.

Combined oil control ring

A combined oil control ring comprising a pair of circular side rails each having a gap, and a waved spacer expander longitudinally sandwiched by the side rails, which has seating tabs for pushing inner surfaces of the side rails on the inner side, (a) the radial thickness aof the side rail being 50-90% of the height aof the spacer expander, or (b) the height aof the seating tab being 23-60% of the height aof the spacer expander.

Growing community of inventors

Kashiwazaki, Japan

Hiroyuki Yabune