In a hydraulic drive system performing the load sensing control by using a pump device having two delivery ports whose delivery flow rates are controlled by a single pump controller, surplus flow is prevented and energy loss at an unload valve and a pressure compensating valve is reduced in combined operations in which two actuators are driven at the same time while producing a relatively large supply flow rate difference therebetween. A boom cylinder 3a is connected so that the hydraulic fluids delivered from delivery ports P1 and P2 of a pump device 1a are merged and supplied to the boom cylinder 3a. An arm cylinder 3h is connected so that the hydraulic fluids delivered from delivery ports P3 and P4 of a pump device 1b are merged and supplied to the arm cylinder 3h. A travel motor 3d is connected so that the hydraulic fluid delivered from one (delivery port P2) of the delivery ports of the pump device 1a and the hydraulic fluid delivered from one (delivery port P4) of the delivery ports of the pump device 1b are merged and supplied to the travel motor 3d. A travel motor 3e is connected so that the hydraulic fluid delivered from the other (delivery port P1) of the delivery ports of the pump device 1a and the hydraulic fluid delivered from the other (delivery port P3) of the delivery ports of the pump device 1b are merged and supplied to the travel motor 3e.

In a hydraulic drive system performing the load sensing control by using a pump device having two delivery ports whose delivery flow rates are controlled by a single pump controller, surplus flow is prevented and energy loss at an unload valve and a pressure compensating valve is reduced in combined operations in which two actuators are driven at the same time while producing a relatively large supply flow rate difference therebetween. A boom cylinder 3a is connected so that the hydraulic fluids delivered from delivery ports P1 and P2 of a pump device 1a are merged and supplied to the boom cylinder 3a. An arm cylinder 3h is connected so that the hydraulic fluids delivered from delivery ports P3 and P4 of a pump device 1b are merged and supplied to the arm cylinder 3h. A travel motor 3d is connected so that the hydraulic fluid delivered from one (delivery port P2) of the delivery ports of the pump device 1a and the hydraulic fluid delivered from one (delivery port P4) of the delivery ports of the pump device 1b are merged and supplied to the travel motor 3d. A travel motor 3e is connected so that the hydraulic fluid delivered from the other (delivery port P1) of the delivery ports of the pump device 1a and the hydraulic fluid delivered from the other (delivery port P3) of the delivery ports of the pump device 1b are merged and supplied to the travel motor 3e.

An actuator includes an actuator housing having a first engagement feature and a motor located within the actuator housing and configured to rotate a driver. The actuator also includes a stroke limiting component coupled to the driver and has a second engagement feature. One of the first and second engagement features is a channel and another of the first and second engagement features is a protrusion. The protrusion is configured to fit within the channel to define a stroke of the actuator based at least in part on a length of the channel or a length of the protrusion.

An actuator includes an actuator housing having a first engagement feature and a motor located within the actuator housing and configured to rotate a driver. The actuator also includes a stroke limiting component coupled to the driver and has a second engagement feature. One of the first and second engagement features is a channel and another of the first and second engagement features is a protrusion. The protrusion is configured to fit within the channel to define a stroke of the actuator based at least in part on a length of the channel or a length of the protrusion.

An actuator includes an actuator housing having a first engagement feature and a motor located within the actuator housing and configured to rotate a driver. The actuator also includes a stroke limiting component coupled to the driver and has a second engagement feature. One of the first and second engagement features is a channel and another of the first and second engagement features is a protrusion. The protrusion is configured to fit within the channel to define a stroke of the actuator based at least in part on a length of the channel or a length of the protrusion.

An actuator includes an actuator housing having a first engagement feature and a motor located within the actuator housing and configured to rotate a driver. The actuator also includes a stroke limiting component coupled to the driver and has a second engagement feature. One of the first and second engagement features is a channel and another of the first and second engagement features is a protrusion. The protrusion is configured to fit within the channel to define a stroke of the actuator based at least in part on a length of the channel or a length of the protrusion.

A device for controlling a propeller, having variable-pitch blades, of a turboprop engine, has a first hydromechanical device for controlling the pitch of the blades of the propeller and a second hydromechanical device for controlling the speed of rotation of the propeller. The device includes a single electromechanical actuator with a movable actuator member mechanically connected both to the first hydromechanical device for controlling the pitch, in order to manage the pitch setpoint, and to the second hydromechanical device for controlling the speed, in order to manage the speed setpoint.

A device for controlling a propeller, having variable-pitch blades, of a turboprop engine, has a first hydromechanical device for controlling the pitch of the blades of the propeller and a second hydromechanical device for controlling the speed of rotation of the propeller. The device includes a single electromechanical actuator with a movable actuator member mechanically connected both to the first hydromechanical device for controlling the pitch, in order to manage the pitch setpoint, and to the second hydromechanical device for controlling the speed, in order to manage the speed setpoint.

A system for automatically coordinating a direction of travel with a position of a turret rotatably mounted on an undercarriage of a hydraulic machine including a hydraulic transmission circuit for connecting a main pump to a bi-directional hydraulic travel motor. The circuit includes a travel control distributor able to vary a driving direction of the motor. The system includes a second hydraulic circuit disposed downstream of a pilot pump providing a pilot pressure. The second circuit includes: a valve controller for controlling a direction of travel, activatable by the operator and able to switch the control distributor by sending different command signals; and a reversing valve, interposed between the valve controller and the control distributor. The system further includes a coordination circuit able to switch or maintain the reversing valve according to the position of the turret and to the command signals.

A system for automatically coordinating a direction of travel with a position of a turret rotatably mounted on an undercarriage of a hydraulic machine including a hydraulic transmission circuit for connecting a main pump to a bi-directional hydraulic travel motor. The circuit includes a travel control distributor able to vary a driving direction of the motor. The system includes a second hydraulic circuit disposed downstream of a pilot pump providing a pilot pressure. The second circuit includes: a valve controller for controlling a direction of travel, activatable by the operator and able to switch the control distributor by sending different command signals; and a reversing valve, interposed between the valve controller and the control distributor. The system further includes a coordination circuit able to switch or maintain the reversing valve according to the position of the turret and to the command signals.