| 摘要 |
PROBLEM TO BE SOLVED: To decrease cost, size, and weight, by using an oil pressure source of a friction clutch hydraulic control system to a transmission switching mechanism. SOLUTION: A driving force distribution device for a four-wheel drive vehicle comprises a friction clutch 26 selectively transmitting torque from a main output shaft to a sub output shaft, and a sub transmission switching power from an input shaft into at least two stages of high-speed and low-speed and transmitting that to the main output shaft. The friction clutch hydraulic system 32 controls changes pressing force of the friction clutch 26 according to the supplied oil pressure of the oil pressure source equipped with a motor 71 and a hydraulic pump 72 to control transmitting torque. A sub transmission hydraulic control system 74A of the sub transmission energizes solenoid switch valves 82, 84, supplies the supplied oil pressure from the hydraulic pump 72 to one of a cylinder chamber of a waiting mechanism 75, and shift-moving a shift fork 56 by a shift rod 58. The waiting mechanism 75 is integrally equipped with a piston/cylinder mechanism driving the shift rod 58. COPYRIGHT: (C)2008,JPO&INPIT
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