Abstract: A hydraulic drive system includes an oil supply device, an oil return device and a hydraulic cylinder circuit component. The circuit component includes a hydraulic cylinder, a first and a second two-position two-way electromagnetic directional valves. The cylinder includes a first chamber and a second chamber that has a piston rod. A first port of the first valve connects with the first chamber and a first port of the second valve connects with the second chamber. When the oil supply device connects to a second port of the first valve and a second port of the second valve connects to the oil return device, the piston rod is extended outwards. When the oil supply device connects to the second port of the second valve and the second port of the first valve connects to the oil return device, the piston rod is retracted.

Abstract: A hydraulic drive system includes an oil supply device, an oil return device and a hydraulic cylinder circuit component. The circuit component includes a hydraulic cylinder, a first and a second two-position two-way electromagnetic directional valves. The cylinder includes a first chamber and a second chamber that has a piston rod. A first port of the first valve connects with the first chamber and a first port of the second valve connects with the second chamber. When the oil supply device connects to a second port of the first valve and a second port of the second valve connects to the oil return device, the piston rod is extended outwards. When the oil supply device connects to the second port of the second valve and the second port of the first valve connects to the oil return device, the piston rod is retracted.

Abstract: The present invention discloses an actuator, which is a combination of a hydraulic control unit and a spring-mass mechanical unit, comprising: a housing, with upper and lower ports; an actuation cylinder in the housing; an actuation piston in the actuation cylinder moveable along the longitudinal axis; a first fluid space; a second fluid space; a first piston rod connected to a first surface of the actuation piston; the second piston rod connected to a second surface of the actuation piston; a fluid bypass; a first spring system connected to the first piston rod, biasing the actuation piston in the second direction; a second spring system biasing the actuation piston in the first direction; a first flow mechanism; a second flow mechanism. The present invention also discloses two other preferred embodiments. The actuator features variable valve lift, low energy consumption, fast dynamic response, soft seating and easy controllability.

Abstract: A variable throttle device comprises at least two fixed throttle orifices and one switch device. The at least two fixed throttle orifices are connected in series; and the switch device is connected in parallel with at least one of the at least two fixed throttle orifices. In another implementation, a variable throttle device comprises at least two throttle passages and one switch device, each of the at least two throttle passages has at least one fixed throttle orifice or a plurality of fixed throttle orifices connected in series, the at least two throttle passages are connected in parallel, and the switch device is connected in series with at least one of the at least two throttle passages to selectively open or close the at least one throttle passage. The variable throttle device can increase or decrease the throttling resistance to meet the requirements of the valve seating velocity under different operating conditions.

Abstract: The present invention discloses an actuator, which is a combination of a hydraulic control unit and a spring-mass mechanical unit, comprising: a housing, with upper and lower ports; an actuation cylinder in the housing; an actuation piston in the actuation cylinder moveable along the longitudinal axis; a first fluid space; a second fluid space; a first piston rod connected to a first surface of the actuation piston; the second piston rod connected to a second surface of the actuation piston; a fluid bypass; a first spring system connected to the first piston rod, biasing the actuation piston in the second direction; a second spring system biasing the actuation piston in the first direction; a first flow mechanism; a second flow mechanism. The present invention also discloses two other preferred embodiments. The actuator features variable valve lift, low energy consumption, fast dynamic response, soft seating and easy controllability.