Mazda Motor Corporation

Morio Kiuchi

Kazuo Oguri

The device of the present invention changes the target value of speed shifting time in an automatic transmission according to the oil temperature of line pressure. According to this device, in the case where the oil temperature of line pressure is high, the quantity of heat generation due to sliding of friction elements can be reduced by shortening the speed shifting time, with the result of improvement of friction elements in durability to heat and reliability.

Speed shifting time control device of automatic transmission

A vehicle power transmission device comprises a torque converter having an input member adapted to be connected with an engine output shaft and an output member, a multiple stage gear transmission mechanism, and a drive shaft having one end connected with the output member of the torque converter and passing through the gear mechanism. The gear mechanism includes a composite type planetary gear unit. A first clutch is provided and has a clutch drum connected with the drive shaft for connecting one gear unit element with the drive shaft through a one-way clutch, which permits power transmission from the drive shaft to the first sun gear. A second clutch is provided adjacent to the first clutch for connecting the drive shaft with the one element. A first brake is disposed with a brake drum around the second clutch and a brake band for frictional engagement with the brake drum. The first and second clutches can be arranged in the brake drum to provide a compact structure.

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Hiroshima, Japan

Morio Kiuchi