Patent ID: 7481053

Claim:
A hydraulic pressurizer system comprising: a drive source for driving a vehicle; a mechanical oil pump, which is driven by said drive source; an electrical motor, which is activated by a battery; an electrical oil pump, which is driven by said electrical motor; a ratio-change mechanism, which is actuated by means of hydraulic oil being supplied from said mechanical oil pump and from said electrical oil pump for establishing a speed change ratio, at which a rotational driving force from said drive source is transmitted to wheels with a rotational speed change; and a control unit, which activates said electrical motor; wherein: said control unit stores in memory a characteristic value and a threshold value for a rotational speed of said electrical motor, said characteristic value being calculated from a temperature of said hydraulic oil and the rotational speed of said electrical motor, and said threshold value corresponding to said characteristic value; and if the rotational speed of said electrical motor becomes equal to or higher than said threshold value for said rotational speed, which threshold value is determined from said characteristic value, while said control unit, having stopped said drive source, is supplying said hydraulic oil from said electrical oil pump to said ratio-change mechanism, then said control unit starts said drive source to supply said hydraulic oil from said mechanical oil pump to said ratio-change mechanism and then stops said electrical oil pump.