Patent ID: 6330928
Filing Date: 2001-12-18
Classification: B60K

Abstract:
A driving force control device for a four-wheel drive vehicle having a prime mover, one pair of driven wheels driven directly by said prime mover, a hydraulic clutch, and another pair of driven wheels driven via said hydraulic clutch, said control device comprising:a first hydraulic pump operatively connected to said one pair of driven wheels and driven thereby,a second hydraulic pump operatively connected to said another pair of driven wheels and driven thereby,wherein the engagement force of said hydraulic clutch is controlled based on the difference between the discharge and intake amounts of the first and second hydraulic pumps due to the difference in rotation of the two hydraulic pumps such that the engagement force increases according to an increase in the difference between discharge and intake amounts,an engagement force control means for controlling the engagement force of said hydraulic clutch by selecting from multiple engagement characteristics in which the responsiveness of the torque transmission by said hydraulic clutch is varied according to the driving conditions of the vehicle, andincluding a hydraulic oil supply passage for carrying the hydraulic oil produced in accordance with the difference between the discharge and intake amounts of said first and second hydraulic pumps, connected to a hydraulic oil pressure chamber in said hydraulic clutch, wherein said engagement force control means includes an orifice provided in a drain oil passage for draining the hydraulic oil in said hydraulic oil pressure chamber and a switching valve provided between said orifice and said hydraulic oil pressure chamber.