Tsubakimoto Chain Company

Sumitomo Electric Industries, Limited

Taichi Okada

Masanori Watanabe

Hiromu Izumida

Yoshiki Natsumeda

A spring steel wire includes a main body made of a steel and having a line shape, and an oxidized layer covering an outer peripheral surface of the main body. The steel constituting the main body contains not less than 0.5 mass % and not more than 0.7 mass % C, not less than 1 mass % and not more than 2.5 mass % Si, not less than 0.2 mass % and not more than 1 mass % Mn, and not less than 0.5 mass % and not more than 2 mass % Cr, with the balance being Fe and unavoidable impurities. The steel constituting the main body has a pearlite structure. The oxidized layer has a thickness of not less than 2 μm and not more than 5 μm. The oxidized layer contains not less than 60 mass % FeO.

Spring steel wire

An object of the present invention is to provide a tensioner that has a reduced number of components and weight, and is easy to assemble. The tensioner has a base member loosely fitted into an open rear end of a cylindrical plunger with a closed front end against the resiliency of a biasing means accommodated inside the plunger. The tensioner includes a plunger stopper mechanism configured such that an engaging part formed on the base member detachably engages an engaging groove provided on an inner circumferential surface of the plunger directly or via another member.

Tensioner

An object of the present invention is to provide a tensioner that has a reduced number of components and lighter weight and is easy to assemble. The tensioner according to the present invention is configured such that a base member is detachably and mechanically joined to a rear end opening of a cylindrical plunger with a closed front end against the resilience of biasing means that is accommodated inside the plunger such as to be freely extend and contract. The joint between the plunger and the base member is a mechanical connection that is one of a thread engagement, a press-fit, and a pin connection.

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Osaka, Japan

Taichi Okada