Hydraulic control device for drive power distribution device

A drive power distribution device comprising:

• a hydraulic clutch for distributing drive power from a driving source of a vehicle to a main driving wheel and an auxiliary driving wheel;
• an oil pump driven with a motor for supplying hydraulic fluid to a piston chamber of the hydraulic clutch;
• a hydraulic fluid sealing valve for sealing hydraulic fluid in an oil passage communicating to the piston chamber from the oil pump;
• an on-off valve for opening and closing the oil passage between the hydraulic fluid sealing vale and the piston chamber;
• a control means for controlling driving of the oil pump using the motor and opening and closing of the on-off valve so as to supply a desired hydraulic pressure to the piston chamber;
• a hydraulic pressure detection means for detecting hydraulic pressure of the oil passage;
• a vehicle speed detection means for detecting vehicle speed of the vehicle;
• and
• a drive power calculation means for calculating drive power of the vehicle,
• the drive power distribution device configured so that by closing the on-off valve and driving the oil pump, a hydraulic pressure detected using the hydraulic pressure detection means has reached a target hydraulic pressure corresponding to drive power calculated using the drive power calculation means, and thereafter fastening power of the hydraulic clutch is maintained at an oil pressure of hydraulic fluid sealed in the oil passage until the on-off valve is opened,
• wherein the control means closes the on-off valve at a hydraulic pressure detected using the hydraulic pressure detection means being equal to or less than a predetermined threshold hydraulic pressure and at a vehicle speed detected using the vehicle speed detected using the vehicle speed detection means being equal to or less than a predetermined threshold vehicle speed.