초록 ▼

A hydraulic power system having a variable displacement hydraulic pump, a hydraulic motor driven by the hydraulic pump for actuating a load, with the pump and motor being connected to constitute a closed hydraulic circuit. A hydraulic servo controls the displacement volume of the pump, and a motor s

A hydraulic power system having a variable displacement hydraulic pump, a hydraulic motor driven by the hydraulic pump for actuating a load, with the pump and motor being connected to constitute a closed hydraulic circuit. A hydraulic servo controls the displacement volume of the pump, and a motor stop arrangement prevents, in its operative position, the motor from rotating. The system includes a control valve responsive to a main line pressure in the closed hydraulic circuit for controlling a hydraulic fluid supply to the hydraulic servo to prevent the main line pressure from substantially exceeding a predetermined level, and a control is responsive to the operation of the hydraulic servo for releasing the motor stop arrangement from the operative position when the hydraulic servo is operating.

대표청구항 ▼

A hydraulic power system comprising a variable displacement hydraulic pump, a hydraulic motor driven by said hydraulic pump for actuating a load of a relatively large inertia, said pump and motor being connected to constitute a closed hydraulic circuit, hydraulic servo means operated by a hydraulic

A hydraulic power system comprising a variable displacement hydraulic pump, a hydraulic motor driven by said hydraulic pump for actuating a load of a relatively large inertia, said pump and motor being connected to constitute a closed hydraulic circuit, hydraulic servo means operated by a hydraulic fluid supplied through a fluid supply line from a hydraulic source for controlling a displacement volume of said pump in accordance with an operation of input means, and pressure control valve means connected in said fluid supply line and responsive to a main line pressure in said closed hydraulic circuit for reducing the supply of said hydraulic fluid to said servo means so as to prevent said main line pressure from exceeding a predetermined level when the main line pressure increases due to the inertia of the load, wherein: motor stop means for preventing, in an operative position thereof, said motor from rotating; first control means responsive to the operation of said input means for enabling the motor stop means to be released from the operative position not later than when said motor is caused to rotate when said input means is operated to initiate rotation of said motor and to be held released from the operative position when said input means is operated to continue rotation of said motor; means including said servo means and said pressure control valve means for watching said main line pressure to hydraulically detect a condition of rotation of said motor and generate a signal indicative of a rotation of said motor when said input means is operated to return to its neutral position, said motor rotation signal comprising a change in condition caused by the operations of said servo means and pressure control valve means in combination; and second control means responsive to said motor rotation signal for enabling said motor stop means to be released from the operative position whereby said motor stop means is maintained in a release from from the operative position when said motor is still caused to rotate due to the inertia of said load after said input means is operated to return to its neutral position, while it is brought into the operative position in the absence of said motor rotation signal when said motor completely ceases to rotate.