Bridgestone Corporation

Oji Paper Co., Ltd.

New Oji Paper Co, Ltd.

Kaoru Okada

Keihachiro Nakajima

Hitoshi Kato

Nobuo Shimozono

Ryoji Kubo

A rubber crawler includes a rubber belt trained around a drive wheel, plural rubber projections that are provided at the rubber belt at intervals along the crawler circumferential direction, that project toward the crawler circumferential inside, that are each formed in a peaked shape widening from an apex portion to a base portion as viewed from the crawler width direction, and that are input with drive force when an engagement pin provided at the drive wheel engages with a circumferential direction rubber wall face, and an embedded member that is embedded in the rubber projections and has a circumferential direction wall face arranged along the circumferential direction rubber wall face as viewed in cross-section along the crawler circumferential direction.

Rubber crawler

A rubber crawler has: an endless rubber belt that is entrained about plural wheels; plural rubber projections that are disposed on the rubber belt and spaced apart from one another in a crawler circumferential direction, project toward an inner peripheral side of the rubber belt, and come into contact with the wheels to limit the movement of the wheels in a crawler width direction; and a low-hardness rubber portion that configures part of an inner peripheral surface of the rubber belt, is disposed between mutually adjacent rubber projections, and is formed by a rubber having a lower hardness than the rubber projections.

Metallic core of rubber crawler

Silicon carbide fibers having an excellent mechanical strength and a superior heat resistance can be produced by the process in which activated carbon fibers having a thickness of 1 to 30 &mgr;m and a BET specific surface area of 700 to 1500 m,/g are reacted with a silicon and/or silicon oxide gas at 1200 to 1500&deg; C. under a reduced pressure or in an inert gas atmosphere; and the resultant SiC fibers are heat treated in the presence of a boron-containing substance and optionally a carbon-containing substance at 1700 to 2300&deg; C. in an inert gas atmosphere, wherein the fibers may be in the form of a shaped article, for example, a sheet or honeycomb structure.

Process for producing silicon carbide fiber

A process for producing silicon carbide fibers is provided, comprising the steps of mixing a silicon supply source powder including a mixture of silicon powder and silicon dioxide powder having a molar mixing ratio of 1:0.1 to 1:2 with activated carbon staple fibers having a length of 0.1 to 50 mm and a fiber thickness of 1 to 20 .mu.m and a specific surface area of 300 to 2000 m.sup.2 /g determined by the BET nitrogen absorption method; and heating the resultant mixture at a temperature of 1200 to 1500.degree. C. to directly convert the activated carbon staple fibers, in an atmosphere substantially free from substances reactive with carbon, silicon, silicon oxides and silicon carbide at the above mentioned temperature, to silicon carbide fibers.

Process for producing silicon carbide fibers

Silicon carbide fibers having a high mechanical strength at a high temperature, an excellent heat resistance and a uniform structure are produced by activating carbon fibers which have been produced by heat-treating organic carbon fibers such as cellulose, polyacrylonitrile or petroleum pitch, polyimide or phenol resin fibers in an oxidative gas atmosphere and carbonizing the heat-treating organic fibers in an inert gas, with an activating gas, for example, water vapor, to convert them to the activated porous carbon fibers having a specific surface area of 100 to 3,000 m.sup.2 /g, a length of 5 mm or more and a thickness of 5 to 100 .mu.m; reacting the activated porous carbon fibers with a silicon monoxide gas at a temperature of 800.degree. C. to 2,000.degree. C. under a reduced pressure of 10.sup.2 Pa or less to convert them to silicon carbide fibers having a length of 5 mm or more, without generating whiskers; and optionally the resultant silicon carbide fibers are heat-treated at a temperature of 800.degree. C. to 2,000.degree. C. in the presence of an oxidative gas.

Method of producing silicon carbide fibers

A silicon carbide material in the form of fibers, sheets or three-dimensionally structured articles useful as a reinforcing material and heat-insulating material, is produced by reacting an activated porous carbon material in the form of, for example, fibers, sheets or three-dimensionally structured articles, and having a specific surface area of 100 to 2500 m.sup.2 /g, with silicon monoxide gas at a temperature of 800.degree. C. to 2000.degree. C. and then heat-treating the resultant silicon carbide material in a non-oxidative gas atmosphere containing nitrogen and substantially no oxygen at a temperature of 800.degree. C. to 2000.degree. C.

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Yokohama, Japan

Kaoru Okada