Honda Giken Kogyo Kabushiki Kaisha

Chuo Hatsujo Kabushiki Kaisha

Nippon Steel Corporation

Suzuki Metal Industry Co., Ltd.

Takashi Otowa

Taisuke Nishimura

Hiroshi Yarita

Masaaki Mikura

Kazuo Yoshida

Masayuki Hashimura

Ikuo Ochiai

Toshinari Sonoda

Toshihiko Matsubara

Toshio Ozone

Shouichi Suzuki

Toshinori Aoki

Masato Yanase

A high-strength oil-tempered steel wire with excellent spring fabrication property that is made of spring low-alloy steel, having a decarburized layer of reduced hardness extending to a depth of not greater than 200 .mu.m from the wire surface, a wire surface hardness in the range from an Hv (Vickers hardness) of 420 to an Hv of 50 below the Hv of the wire interior, and an Hv at the interior of the wire beyond the depth of the decarburized layer of not less than 550. The spring low-alloy steel can preferably comprise, in weight percent, 0.45-0.80% C, 1.2-2.5% Si, 0.5-1.5% Mn, 0.5-2.0% Cr and the balance of Fe and unavoidable impurities. The method for producing the foregoing steel wire comprises the steps of continuously passing and heating a starting material low-alloy steel wire fed through a furnace body through-pipe of a continuous heating furnace for oil tempering, decarburizing the low-alloy steel wire under regulation of a dew point of a decarburizing atmosphere in the pipe by introducing into the pipe from its inlet side or a desired intermediate point thereof hydrogen gas or a mixed gas of hydrogen gas and an inert gas and, to form steam by reaction therewith, oxygen gas or an oxygen-containing gas and controlling the amount of oxygen gas or oxygen-containing gas introduced, and thereafter quenching and annealing the low-alloy steel wire.

High-strength oil-tempered steel wire with excellent spring fabrication

In a manufacturing method of a valve spring, a coiled valve spring made of an oil-tempered wire is applied with nitriding treatment and is supported to be rotated about its center axis. During a shot peening process of the coiled valve spring, cut wires of Hv 650 to 850 in hardness and 1.0 to 0.6 mm in diameter are shot to the coiled valve spring at a first step, in a roller-type shot machine and cut wires of Hv 650 to 850 in hardness and 0.4 to 0.2 mm in diameter are shot to the coiled valve spring at a second step in a tumbling shot machine, the time for the second step being longer than the time for the first step.

Manufacturing method of valve spring superior in durability

A coil spring made of an oil-tempered steel wire with internal hardness of more than Hv 550 in cross-section, the surface hardness of the oil-tempered steel wire being determined in an extent between Hv 420 in a minimum value and hardness defined by subtraction of Hv 50 from the internal hardness in a maximum value.

Coil spring resistive to delayed fracture and manufacturing method of

The present invention provides, at low cost, a valve spring steel having a tensile strength as high as 210 to 240 kgf/mm.sup.2 after oil tempering. The high strength spring steel comprises, based on weight, 0.65 to 0.85% of C, 1.90 to 2.40% of Si, 0.50 to 1.00% of Mn, 0.70 to 1.30% of Cr, 0.10 to 0.30% of Mo, 0.20 to 0.50% of V, 0.01 to 0.04% of Nb and the balance Fe and unavoidable impurities and is subjected to heating at temperature of 1,050 to 1,250.degree. C. and then to rolling so that carbides in the steel have a size of up to 0.15 .mu.m in terms of equivalent circle. A valve spring having a tensile strength as high as 210 to 240 kgf/mm.sup.2 after oil tempering and stabilized quality can be produced while the material cost is greatly reduced by decreasing costly alloying components as much as possible.

High strength spring steel and process for producing same

A valve operating mechanism for operating a valve in an internal combustion engine includes a hydraulic lash adjuster for imposing a hydraulic pressure against a cam follower slidably engaging a camshaft. The hydraulic lash adjuster includes a plunger slidably disposed in a cylinder and defining an oil chamber communicating with a pressure chamber between the plunger and the cylinder through a valve hole which can selectively be opened and closed by a free-ball check valve. The plunger is normally urged by a spring to move in a direction out of the cylinder toward the cam follower. The cam follower acts on an end of the valve stem of the valve through an interlink mechanism having an adjusting device for adjusting the volume of the pressure chamber of the hydraulic lash adjuster.

Hydraulic lash adjuster for use in valve operating mechanism

Growing community of inventors

Wako, Japan

Takashi Otowa