Patent ID: 6189641
Filing Date: 2001-02-20
Classification: B60K,B60Y,F16H

Abstract:
A four-wheel hydraulic drive system for a working vehicle comprising:a variable displacement hydraulic pump;a first fixed displacement hydraulic motor fluidly connected with said hydraulic pump;a pair of first driving wheels driven by said first hydraulic motor;a second fixed displacement hydraulic motor fluidly connected with said hydraulic pump;a pair of second driving wheels driven by said second hydraulic motor; andmeans for changing the torque of said second hydraulic motor, wherein said means substantially equalizes the torque of said second hydraulic motor to that of said first hydraulic motor for providing a first four-wheel drive mode of said vehicle, and reducing the torque of said second hydraulic motor to be smaller than that of said first hydraulic motor for providing a second four-wheel drive mode of said vehicle.