Honda Motor Co., Ltd.

Tanaka Seimitsu Kogyo Co., Ltd.

Sumitomo Electric Industries, Limited

Honda Giken Kogyo Kabushiki Kaisha

Toyo Aluminium Kabushiki Kaisha

Meira Co., Ltd.

Kosuke Doi

Hiroyuki Horimura

Yoshinobu Takeda

Hisao Hattori

Toshihiko Kaji

Jun Kusui

Kyo Takahashi

Koji Yamada

Kazuo Fujii

Masahiro Sawai

Hideaki Sumitomo

Kazuhiko Yokoe

Masaya Takata

Yoshikazu Kanazawa

A process which can make a titanium alloy bolt at ambient temperature is disclosed. A Ti&#x2014;Fe&#x2014;O alloy is used as a material. It has a screw thread formed thereon by drawing and rolling.

Titanium alloy bolt and its manufacturing process

To provide a valve spring retainer made of titanium, capable of reduction in raw material cost and processing cost, a valve spring retainer is formed out of a titanium alloy raw material composed of 0.8 wt %&#x2266;Fe&#x2266;1.2 wt %, 0.24 wt %&#x2266;O&#x2266;0.32 wt %, 0.02 wt %&#x2266;N&#x2266;0.05 wt %, and balance Ti containing unavoidable impurities through cold forging.

Valve spring retainer made of titanium

A lightweight and high-strength valve lifter is excellent in wear resistance and sliding properties. The valve lifter is made of a titanium alloy having a hardened layer on the top surface thereof, on which a cam is caused to slide. The hardened layer is composed of an &#x3b1;-case and an oxygen diffusion layer under the &#x3b1;-case. The &#x3b1;-caseis formed in a thickness of not less than 3 &#x3bc;m and not more than 15 &#x3bc;m. The oxygen diffusion layer has a thickness of not less than 10 &#x3bc;m. The hardened layer on the top surface of the valve lifter is formed by oxidation treatment in a furnace at a temperature of not less than 600&#xb0; C. An outermost oxide layerformed on the &#x3b1;-case as a result of the oxidation treatment is removed.

Titanium alloy valve lifter

A valve lifter and a method of manufacture thereof is provided in which sliding properties of a cam on a cam-contacting sliding surface in an upper surface of a valve lifter are improved by forming the cam-contacting sliding surface as a concave surface to permit retention of lubricating oil therein. The cam-contacting sliding surface is integrally provided in an outer wall of an upper part of a valve lifter. The cam-contacting sliding surface is formed as a concave surface to provide better retention of the lubricating oil. The concave sliding surface is formed during high temperature oxidation of the valve lifter by permitting the natural slumping down of the upper part due to its own weight under the gravity.

Method of making a valve lifter

A spring retainer formed from a titanium alloy and comprising a cylinder and a brim formed integrally with the cylinder is disclosed. The brim has on a top thereof a slope formed such that a thickness of the brim decreases radially outwardly.

Spring retainer and method for manufacturing the same

A raw material for powder metallurgy contains at least 0.5 vol % and at most 10 vol % of alumina powder of which the sieve fraction with a sieve opening of 30 .mu.m is at most 0.1 wt %, and a remaining part of aluminum alloy powder. The moisture content of the alumina powder is at most 0.15 wt. % with respect to the alumina powder. Agglomeration of particles is thereby minimized or avoided. Highly reliable raw material for powder metallurgy having superior fatigue strength, impact resistance and wear resistance can be obtained. A method of preparing such a mixed powder raw material involves air classifying the powder materials, dry ball mixing the materials, and then annealing the mixed powder.

Raw material for powder metallurgy and manufacturing method thereof

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Wako, Japan

Kosuke Doi