Mitsuboshi Belting Ltd.

Susumu Yamakawa

Hideo Hirai

Masakatsu Ando

Yasuhiro Hashimoto

Norikazu Tanaka

Naoki Fujimoto

Kyoichi Mishima

Minori Kawaguchi

A power transmission system having: a power transmission belt with a tensile strength such that a force of at least 17 kgf per 1 mm width is required to effect a 1% elongation of the belt; a plurality of pulleys with which the power transmission belt is operatively engaged; and an auto-tensioner having an element to engage the power transmission belt. The auto-tensioner has a damping ratio that is not greater than 20%, where the damping ratio is defined by the following formula: Damping ratio=2[(A-B)/(A+B)].times.100, where A is the force exerted by the auto-tensioner element during up-stroking of the auto-tensioner element and B is the force exerted by the auto-tensioner element during down-stroking of the idler pulley. More preferably, the damping ratio is 10-20%.

Power transmission system

An apparatus is provided for tensioning a drive belt, which apparatus consists of tensioner arm having an idler pulley thereon for engagement with the surface of a drive belt, structure for mounting the tensioner arm to a support for pivoting movement in first and second opposite directions relative to the support, and a torsion coil spring formed of wire and acting between the mounting structure and tensioner arm for biasing the tensioner arm in one of the first and second directions. The wire has a non-circular cross section.

Compact coil spring tensioner

An apparatus for tensioning a belt consisting of a tensioner arm having an idler pulley for engagement with a surface of a drive belt, structure for mounting the tensioner arm to a suppport for pivoting movement about a pivot axis in first and second opposite directions, and structure for biasing the tensioner arm in one of the first and second directions. The mounting structure includes first and second members with first and second relatively movable cooperating friction generating surface for damping rotation of the tensioner arm. At least a portion of one of the friction generating surfaces is concave opening towards the tensioner with at least one of the friction generating surfaces having at least a portion defined by other than a radius centered on the pivot axis of the tensioner arm to thereby produce a greater resistance to rotation of the tensioner arm in the other of the first and second directions than in the one of the first and second tensioner arm pivoting directions.

Apparatus for automatically tensioning a drive belt

Apparatus for testing a power transmission drive intended for use with a reciprocating engine by use of an electric drive motor in lieu of the engine. The motor is provided in an adjustable input shaft driving unit which provides a variable speed drive of the power transmission drive correponding to a variable speed drive effected by a reciprocating engine. In one form, the drive speed is varied by a controlled brake which, in the illustrated embodiment, is an eddy current brake. The brake may be utilized in conjunction with a variable speed input shaft driving unit for providing a second speed variation or may be used independently thereof. Alternatively, the electric motor may be operated by a control arranged to provide a speed variation of the electric motor corresponding accurately with the reciprocating engine characteristics. Control circuity for effecting the desired brake control and motor control are disclosed.

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Kobe, Japan

Susumu Yamakawa