Patent ID: 7137469
Filing Date: 2006-11-21
Classification: B60K,B62D

Abstract:
1. A running power transmission mechanism for a vehicle for transmitting drive power from a driving source to a pair of steering wheels and a pair of non-steering wheels, which are respectively disposed closer to first and second sides of the vehicle in a fore and aft direction thereof, comprising: a main-hydrostatic transmission having a steering-wheel drive output shaft for driving the pair of steering wheels and a non-steering-wheel drive output shaft for driving the pair of non-steering wheels, said main-hydrostatic transmission being constructed so as to output synchronized drive power to the pair of steering wheels and the pair of non-steering wheels through the steering-wheel drive output shaft and the non-steering-wheel drive output shaft, respectively; a non-steering-wheel differential gear mechanism for receiving drive power from said main-hydrostatic transmission through the non-steering-wheel drive output shaft, and driving the pair of non-steering wheels differentially; a sub-hydrostatic transmission for non-stepwisely changing the speed of drive power inputted via the steering-wheel drive output shaft and outputting the drive power to the pair of steering wheels, in which said sub-hydrostatic transmission is switchable between a standard transmission state, which outputs power enabling the pair of steering wheels to have an average peripheral speed substantially equal to an average peripheral speed of the pair of non-steering wheels, and a higher speed transmission state, which outputs power enabling the pair of steering wheels to have an average peripheral speed higher than an average peripheral speed of the pair of non-steering wheels; a steering-wheel differential gear mechanism for receiving drive power from said sub-hydrostatic transmission, and driving the pair of steering wheels differentially; said main-hydrostatic transmission including a main-pump shaft operatively connected with the driving source, a main-hydraulic pump body driven by the main-pump shaft, a main-hydraulic motor body fluidly connected with the main-hydraulic pump body, and a main-motor shaft driven by the main-hydraulic pump body; said main-motor shaft having first and second ends that respectively extend to the first and second sides of the vehicle with respect to the main-hydraulic motor body, said first and second ends of said main-motor shaft serving as the steering-wheel drive output shaft and the non-steering-wheel drive output shaft, respectively; and said sub-hydrostatic transmission including a sub-pump shaft operatively connected with the first end of the main-motor shaft, a sub-hydraulic pump body driven by the sub-pump shaft, a sub-hydraulic motor body fluidly connected with the sub-hydraulic pump body, a sub-motor shaft driven by the sub-hydraulic motor body and outputting drive power to the steering-wheel differential gear mechanism, and an output adjusting member that is operated according to a steering angle of the pair of steering wheels and allows the sub-motor shaft to output drive power to the steering-wheel differential gear mechanism with its speed non-stepwisely changed based upon an operational state of said output adjusting member.