Patent ID: 6016883
Filing Date: 2000-01-25
Classification: B60K

Abstract:
A two wheel/four wheel drive shifting device for a vehicle, comprising:a transfer mechanism for distributing driving force from an internal combustion engine to front and rear wheels;a two/four wheel drive shifting mechanism for shifting between two and four wheel drive whereby the driving force to be delivered to said wheels through said transfer mechanism is interrupted in order to allow shifting between two wheel drive and four wheel drive;said two/four wheel drive shifting mechanism including a shift-detecting means for detecting the shift between two wheel drive and four wheel drive;an indicating means for indicating the shifting;a free wheel mechanism disposed in one of a front wheel differential mechanism near said front wheels and a rear wheel differential mechanism near said rear wheels;an actuator for shifting said free wheel mechanism between a free state and a locked state;a pressure pump for supplying said actuator with a working pressure;a pressure-detecting means for detecting the working pressure supplied to said actuator; anda control means for controlling said pressure pump in order to supply the working pressure to said actuator when said shift-detecting means detects shifting to four wheel drive, said control means also controlling to deactivate said pressure pump and actuating said indicating means to show a success in shifting to four wheel drive when said pressure-detecting means detects that the working pressure has achieved a predetermined pressure at which the shifting of said free wheel mechanism to the locked state is completed, and said control means actuating said indicating means to show a failure in shifting of said free wheel mechanism into the locked state when said pressure-detecting means detects that the working pressure has not achieved the predetermined pressure after a predetermined time elapses after said pressure pump is actuated.