Suncall Corporation

Toyota Jidosha Kabushiki Kaisha

Denso Corporation

Keiichiro Teratoko

Ryuji Kishihara

Naoya Wada

Akio Kidooka

Yuu Yokoyama

Takao Suzuki

Tadashi Saito

Akira Hori

Yoshiro Yamada

Hiroshi Suzuki

Hironobu Sasada

Kazuhiro Uzumaki

Masaaki Ishida

Futoshi Fujiwara

Yuji Isono

Kazuo Kataoka

A method includes a spiral forming step causing a substantially linear elongated member, conveyed toward one side in a longitudinal direction of the elongated member by a pair of conveying rollers, to be engaged at one side in a second direction with a pressing member movable in the second direction so that a spiral body including the fixed coil part, the first movable coil part and the second movable coil part is formed from the linear elongated member. The spiral forming step is configured to control the position of the pressing member with respect to the second direction, based on a signal from a rotational speed sensor detecting the rotational speed of the conveying roller, a relationship between a position in the longitudinal direction of the elongated member that is engaged with the pressing member and the position in the circumferential direction after the spiral body is formed.

Spiral spring manufacturing method

At least a first movable coil part of a plurality of movable coil parts that is in the innermost place in the radial direction does not come into contact with both the fixed coil part, which is radially adjacent inwardly, and a second movable coil part, which is radially adjacent outwardly, at the same place in the circumferential direction while coming into contact with only one of the fixed coil part and the second movable coil part in a plurality of places that are circumferentially displaced, when the spiral spring is in an elasticity retaining state reached from a free length state by elastic deformation in the diameter-reducing direction.

Spiral spring

A sealing region where a valve seat and an outer peripheral surface of a enlarged diameter portion of a flare portion are contacted to each other is configured so that an end on a side opposite a combustion chamber is positioned at a position same as or on a side away from the combustion chamber than an end on a side close to the combustion chamber of a connecting region where a lid member and an inner peripheral surface of the enlarged diameter portion are connected with respect to the axis line direction.

Valve structure for internal combustion

Hard metal particles having hardness which is lower than the hardness of a nitrided outermost layer of a spring and in the range of Hv 500 to 800 and a diameter of 500 to 900 &mgr;m are protected against the nitrided surface of the spring at a velocity of 40 to 90 m/sec to prevent generation of a microcrack in the surface layer and provide a compression residual stress comparatively deep inside the spring. Against the resultant spring surface, a number of fine metal particles having a mean diameter of all particles of 80 &mgr;m or less, a mean diameter of each particle in the range between 10 &mgr;m inclusive and less than 100 &mgr;m, a spherical or near spherical shape with no square portions, a specific gravity of 7.0 to 9.0, and hardness which falls in the range between Hv 600 and Hv 1100 inclusive and is equal to or less than the hardness of the outermost surface layer of the spring after nitriding, at a velocity of 50 to 190 m/sec., while controlling temperature to be low enough to cause work hardening but not to cause softening due to recovery/recrystallization, to provide a high compression residual stress in a near surface layer without generation of microcracks in the surface layer and thus obtain a valve spring and the like excellent in fatigue strength.

Spring with excellent fatigue endurance property and surface treatment method for producing the spring

A sheet of strip material of metal is coiled into a ring-like member, with a broader surface thereof being oriented in a radial direction. Opposite ends of the sheet of strip material are connected together by a joint. The joint includes a concave portion and a convex portion which are adapted to be engaged with each other against a repulsive force in a circumferential direction. The ring-like member is formed, on the inner periphery thereof, with teeth for engagement with a gear of a transmission, thereby producing a friction plate.

Thin-walled ring-shaped member and method of manufacturing same

Growing community of inventors

Kyoto, Japan

Keiichiro Teratoko