| 摘要 |
PURPOSE:To reduce the driving power of a power steering gear and the consumption of energy, by driving two pumps of large and small capacity in very slow operation but disengaging an electromagnetic clutch to drive only the pump of small capacity in medium or rapid operation. CONSTITUTION:When a vehicle is run at a very low speed, the coil 103 of an electromagnetic clutch 10 is energized by the signal of a controller 28 to attract a drive plate 102 to engage the clutch 10. At that time, the rotation of an engine is transmitted to drive shafts 11, 12 through a pulley 5 to actuate both pumps 32, 31 of large and small capacity. When the speed of the vehicle is increased, the coil 103 is deenergized by the signal of a vehicle speed sensor 26 or a pressure sensor 27 to disengage the clutch 10 to actuate only the pump 31 of small capacity. When the vehicle speed is increased further, the quantity of oil discharged from the pump 31 is augmented in proportion to the increase in the vehicle speed but a variable throttle valve 21 and a flow control valve 8 are operated to by-pass excess oil to a reserve tank to keep constant the oil supply to a power control valve 2. |
