Nissan Motor Company Limited

Nhk Spring Co., Ltd.

Honda Giken Kogyo Kabushiki Kaisha Nhk Spring Co., Ltd.

Kaoru Hatayama

Noritoshi Takamura

Makoto Abe

Hideo Yamamoto

Atsushi Ishida

Yuichi Nagase

Naoki Terakado

Akihiko Inooku

Taizo Fukutome

Toyoyuki Higashino

Tsuyoshi Kuriki

Tetsuyuki Taniguchi

A spring system for applying a restoring force to a reciprocating member such as an exhaust or intake valve of an internal combustion engine, comprising: a helical spring having open ends and consisting of titanium or an alloy thereof; and a spring seat supporting one of the two ends of the helical spring. Since this helical spring is provided with open ends, mutual striking of the coil wire can be avoided and, thereby, the durability of the helical spring can be ensured in addition to the advantage obtained from the low-mass and high transverse elastic modulus of titanium or its alloy.

Spring system

A high strength spring is made of steel of which composition consists of 0.6 to 0.7 wt % of C, 1.2 to 1.6 wt % of Si, 0.5 to 0.8 wt % of Mn, 0.5 to 0.8 wt % of Cr, 0.05 to 0.2 wt % in total of one or more than one of V, Mo, Nb and Ta and the balance of Fe and inevitable impurities. The steel is limited in particle size of non-metallic inclusions in such a way that the maximum particle size of the non-metallic inclusions is equal to or smaller than 15 .mu.m. The spring is applied at a portion adjacent the outer surface thereof with a residual compression stress in such a way that the maximum of the residual compression stress ranges from 85 to 110 Kgf/mm.sup.2. The spring is further process so as to have such a surface roughness that is equal to or smaller than 15 .mu.m.

High strength spring and its process of manufacturing

Growing community of inventors

Nagano, Japan

Kaoru Hatayama