摘要:
A system for simultaneously operating first and second hydraulic cylinders (14,16) has an inlet node for connection to a source of pressurized fluid (12) and an outlet node for connection to a tank (19). A two-position, three-way primary control valve (22) has a first port connected to the inlet node, a second port connected to the outlet node, and a common port. A first electrohydraulic proportional valve (32) connects the common port to a first port of the first cylinder (14), and a second electrohydraulic proportional valve (36) connects the common port to a first port of the second cylinder (16). A third electrohydraulic proportional valve (42) connects the inlet node to a second port of the first cylinder (14) and a second port of the second cylinder (16). A fourth electrohydraulic proportional valve (44) connects the tank (19) to a second port of the first cylinder (14) and to a second port of the second cylinder (16). Selectively operating the primary control valve and one of the third and fourth electrohydraulic proportional valves determines the direction in which the first and second cylinders move. Operation of the first and second electrohydraulic proportional valves meters hydraulic fluid to or from the first and second cylinders to control the rate of that movement.
摘要:
A system for simultaneously operating first and second hydraulic cylinders (14,16) has an inlet node for connection to a source of pressurized fluid (12) and an outlet node for connection to a tank (19). A two-position, three-way primary control valve (22) has a first port connected to the inlet node, a second port connected to the outlet node, and a common port. A first electrohydraulic proportional valve (32) connects the common port to a first port of the first cylinder (14), and a second electrohydraulic proportional valve (36) connects the common port to a first port of the second cylinder (16). A third electrohydraulic proportional valve (42) connects the inlet node to a second port of the first cylinder (14) and a second port of the second cylinder (16). A fourth electrohydraulic proportional valve (44) connects the tank (19) to a second port of the first cylinder (14) and to a second port of the second cylinder (16). Selectively operating the primary control valve and one of the third and fourth electrohydraulic proportional valves determines the direction in which the first and second cylinders move. Operation of the first and second electrohydraulic proportional valves meters hydraulic fluid to or from the first and second cylinders to control the rate of that movement.
摘要:
A regeneration method for a hydraulic system enables the fluid being forced from a first actuator (110) to be used to power a second actuator (114). Often the force of the load acting on a hydraulic actuator (110) is used to move the actuator (110) into a given position which motion forces fluid from the actuator (110). Rather than simply draining that fluid to the system tank (120), the fluid is routed to a second actuator (114) to be powered when the pressure of the fluid draining at the first actuator (110) is greater than the pressure required to power the second actuator (114). At other times the draining fluid can be used to drive the pump (102) which has been configured to operate as a motor thereby driving the prime mover (104) connected to the pump. Alternatively the draining fluid can be routed to an accumulator (145) where it is stored under pressure until needed to power an actuator (110,114) of the system. A bidirectional pilot operated poppet valve (10) is also disclosed.
摘要:
When a swinging boom (15) driven by a hydraulic cylinder (19) stops, inertia causes continued motion of the boom which increases pressure in a chamber (40,42) of the hydraulic cylinder. Eventually that pressure reaches a level which causes the boom to reverse direction. Then pressure in an opposite cylinder chamber (42,40) increases until reaching a level that causes the boom movement to reverse again. This oscillation continues until the motion is dampened by other forces acting on the boom. As a result, an operator has difficulty in properly positioning the boom. To reduce this oscillating effect, a sensor (48,49) detects when the cylinder chamber pressure increases above a given magnitude and then a determination is made when the rate of change of that pressure is less than a defined threshold. Upon that occurrence, a control value (33,34) is opened to relieve the pressure in that cylinder chamber (42,40).
摘要:
A regeneration method for a hydraulic system enables the fluid being forced from a first actuator (110) to be used to power a second actuator (114). Often the force of the load acting on a hydraulic actuator (110) is used to move the actuator (110) into a given position which motion forces fluid from the actuator (110). Rather than simply draining that fluid to the system tank (120), the fluid is routed to a second actuator (114) to be powered when the pressure of the fluid draining at the first actuator (110) is greater than the pressure required to power the second actuator (114). At other times the draining fluid can be used to drive the pump (102) which has been configured to operate as a motor thereby driving the prime mover (104) connected to the pump. Alternatively the draining fluid can be routed to an accumulator (145) where it is stored under pressure until needed to power an actuator (110,114) of the system. A bidirectional pilot operated poppet valve (10) is also disclosed.