Main Content

Hydraulic Actuator with Dual Counterbalance Valves

Open Model

This example shows an actuator controlled by a 4-way directional valve and loaded with an overriding load, requiring the use of counterbalance valves to prevent the load from creeping when the directional valve is in the neutral position. In the neutral position, the directional valve connects ports A and B to the reservoir while blocking the pressure port P. The counterbalance valves block flow from returning to the reservoir, thus holding the actuator in place.

The valve actuator represents the electromagnets that control the directional valve position. When electromagnet B is energized, the directional valve is in the negative position and connects ports A and B to the pressure port P. This causes the actuator to extend due to the difference in the piston areas. Flow passes through the check valve in counterbalance valve A to enter cylinder chamber A, while pressure in the pilot line opens the orifice in counterbalance valve B to permit return flow from cylinder chamber B.

When electromagnet A is energized, the directional valve is in the positive position and connects port B to the pressure port P and port A to the reservoir. This causes the actuator to retract. Flow passes through the check valve in counterbalance valve B to enter cylinder chamber B, while pressure in the pilot line opens the orifice in counterbalance valve A to permit return flow from cylinder chamber A.

Model

Simulation Results from Scopes

Simulation Results from Simscape Logging

This plot shows the pressures in the two cylinder chambers and the position of the piston.

This plot shows the port pressures and flow rates for counterbalance valve A. In the first part of the simulation, flow passes through the check valve inside the counterbalance valve, allowing liquid to enter the cylinder chamber A to extend the piston. In the second part of the simulation, flow returning from the cylinder chamber A is controlled by the orifice inside the counterbalance valve. Pressures at port P and L must be sufficiently large to open the orifice and permit return flow.

This plot shows the port pressures and flow rates for counterbalance valve A. In the first part of the simulation, flow returning from the cylinder chamber B is controlled by the orifice inside the counterbalance valve. Pressures at port P and L must be sufficiently large to open the orifice and permit return flow. In the second part of the simulation, flow passes through the check valve inside the counterbalance valve, allowing liquid to enter the cylinder chamber B to retract the piston.

Related Topics