Bando Chemical Industries, Inc.

Katsuyoshi Fujiwara

Hideaki Kawahara

Shigeki Okuno

Tsutomu Shioyama

Yuji Sekiguchi

Yoshiyuki Kitano

Yuji Nakamoto

Kenji Kusaka

Tomoaki Suzuki

A toothed belt includes: a belt body having a flat band-shaped back rubber portion and tooth rubber portions placed on an inner circumferential side of the back rubber portion, the back rubber portion and the tooth rubber portions being each composed of a thermoplastic elastomer composition; a cord containing carbon filaments; and a tooth portion covering material provided on an inner circumferential side of the belt body and covering the tooth rubber portions. An elastomer component of the thermoplastic elastomer composition is a TPAE or a TPC, a hardness of the thermoplastic elastomer composition forming the back rubber portion is not less than 25 and not greater than 70, a hardness of the thermoplastic elastomer composition forming the tooth rubber portions is not less than 40 and not greater than 70, and the hardness of the thermoplastic elastomer composition forming the back rubber portion is not greater than the hardness of the thermoplastic elastomer composition forming the tooth rubber portions.

Toothed belt

The invention provides a power transmission belt which is superior in oil resistance so that it is swollen to only a reduced degree, reduced in hardness, and small in abrasion if the rubber layers are stained with oil while the belt is being used in an oil-present environment. Such a power transmission belt has rubber layers which comprise a compression rubber layer and an adhesion rubber layer both of which are vulcanized and bonded to each other and load carrying cords are embedded in the adhesion rubber layer, wherein at least the compression rubber layer between the two rubber layers is formed of vulcanizate obtained by vulcanizing ethylene-&#x3b1;-olefin-diene rubber with an organic peroxide and a trifunctional co-crosslinking agent.

Power transmission belt

A power transmission belt is formed so that the back face side of a belt body is covered with a reinforced fabric woven with warps and wefts. In the reinforced fabric, the direction of warps and the direction of wefts make equal angles with the belt widthwise direction, and each of two directions of consecutive yarn intersections of the warps and wefts formed to stand out from the belt surface makes a certain angle with the belt widthwise direction.

Power transmission belt and belt drive system with the same

The belt body of a power transmission belt is composed of a rubber composition comprising ethylene-&aacute;-olefin elastomer as the raw material rubber. The ethylene-&aacute;-olefin elastomer as the raw material rubber comprises 7 to 12 mass % of a high molecular weight component having a molecular weight of 10 or more and an ethylene content of 65 mass % or more, and 26 to 60 mass % of a low molecular weight component having a molecular weight of 10 or less and an ethylene content of 60 mass % or less, and the ethylene-&eacute;-olefin elastomer has a Mooney viscosity of 50 ML or less (100 C.).

A power transmission belt having as the main constituent a rubber composition which comprises not less than 50% by weight, on the total polymer component basis, of an ethylene/&agr;-olefin/diene terpolymer with sulfur incorporated therein as a curing or vulcanizing agent.

A V-ribbed belt having a rib rubber layer which includes a plurality of ribs extending under a tension member layer of a power transmission belt along the longitudinal direction of the belt. Short fibers are mixed in the ribs. The direction of orientation of the short fibers is near the longitudinal direction of the belt near the tension member layer and gradually changed toward near the vertical direction of the belt near the rib tops. Through the above arrangement, endurance to the shearing stress can be improved and flexibility is also maintained and consequently, endurance to rib chipping off is improved.

A transmission belt including a part formed by a vulcanized product of a rubber composition comprising 100 parts by weight of chloroprene rubber, 1 to 30 parts by weight of zinc powder and 0.5 to 10 parts by weight of 4,4'-(.alpha.,.alpha.-dimethylbenzyl)diphenylamine, and having a high level of dynamic heat resistance and a long life.

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Kobe, Japan

Katsuyoshi Fujiwara