A flow path switching valve includes a block-shaped body having a first opening and a second opening which communicate with each other via a linear first oil path, and a third opening which communicates with the first oil path via a linear second oil path; a valve body which is provided so as to be rotatable relative to the body, and in which a communication flow path is formed that allows two openings to communicate with each other depending on the rotation position; and a locking protrusion which regulates the rotation range of the valve body in order to select the rotation position of the valve body to be a predetermined rotation position where two openings of a predetermined combination among the three openings communicate with each other via the communication flow path of the valve body.

A flow path switching valve includes a block-shaped body having a first opening and a second opening which communicate with each other via a linear first oil path, and a third opening which communicates with the first oil path via a linear second oil path; a valve body which is provided so as to be rotatable relative to the body, and in which a communication flow path is formed that allows two openings to communicate with each other depending on the rotation position; and a locking protrusion which regulates the rotation range of the valve body in order to select the rotation position of the valve body to be a predetermined rotation position where two openings of a predetermined combination among the three openings communicate with each other via the communication flow path of the valve body.

An example valve includes: a valve body defining a bore, an inlet port, an outlet port, and a signal cavity; a spool movable in the bore to shift between a first position and an intermediate position, where the spool has a first end and a second end, where the outlet port is fluidly connected to the second end, where the valve body defines a spring cavity adjacent the first end of the spool to house a spring, where the first end is subjected to a load-sense pressure signal, and where when the spool is in the first position, the spool disconnects the inlet port from the outlet port and connects the inlet port to the signal cavity; and a valve actuator that, when activated, connects the signal cavity to the second end of the spool to move the spool in the bore from the first position to the intermediate position.

An energy storage system includes a vessel for storing water, an energy conversion device, and a connection line connecting the vessel with the energy conversion device. The energy conversion device includes first and second housings, a pump turbine in the first housing, and a motor generator in the second housing. The pump turbine includes a first shaft and an impeller mounted on the first shaft. The motor generator includes a second shaft and a rotor at the second shaft for rotating relative to a stator. The second shaft is coupled to the first shaft for transmitting torque between the first and second shafts. The connecting line connects a low pressure opening with an opening for receiving water or discharging water. The second housing is filled with a gas for a barrier pressure during operation of the energy conversion device, such that the rotor rotates within the gas.

An energy storage system includes a vessel for storing water, an energy conversion device, and a connection line connecting the vessel with the energy conversion device. The energy conversion device includes first and second housings, a pump turbine in the first housing, and a motor generator in the second housing. The pump turbine includes a first shaft and an impeller mounted on the first shaft. The motor generator includes a second shaft and a rotor at the second shaft for rotating relative to a stator. The second shaft is coupled to the first shaft for transmitting torque between the first and second shafts. The connecting line connects a low pressure opening with an opening for receiving water or discharging water. The second housing is filled with a gas for a barrier pressure during operation of the energy conversion device, such that the rotor rotates within the gas.

Disclosed are a hydraulic system for construction equipment and a method of controlling the same, and the hydraulic system for construction equipment includes: a plurality of pressure control-type hydraulic pumps driven by an engine provided in construction equipment; an actuator driven by working oil discharged from the hydraulic pump; a closed center-type main control valve provided between the hydraulic pump and the actuator, and bypassing a virtual flow rate; and a controller configured to control the hydraulic pump by receiving the bypassed virtual flow rate from the main control valve.

Disclosed are a hydraulic system for construction equipment and a method of controlling the same, and the hydraulic system for construction equipment includes: a plurality of pressure control-type hydraulic pumps driven by an engine provided in construction equipment; an actuator driven by working oil discharged from the hydraulic pump; a closed center-type main control valve provided between the hydraulic pump and the actuator, and bypassing a virtual flow rate; and a controller configured to control the hydraulic pump by receiving the bypassed virtual flow rate from the main control valve.

A hydraulic system is provided for controlling one or more piston-cylinders of an implement. An implement valve includes at least one spool operable to transition between a neutral position and an open position. A variable displacement pump is operable to move a fluid from a reservoir into a supply conduit and to the at least one spool. A flow control valve, distinct and separate from the at least one spool is located in-line with the supply conduit between the variable displacement pump and the at least one spool, and is operable to simultaneously provide the fluid to the implement valve and to a bypass pathway. The bypass pathway extends from the flow control valve to the reservoir without intervening valving. Each of the at least one spool is operable to permit increased fluid flow to a corresponding piston cylinder of the implement when in the open position. The variable displacement pump is operable to vary a flow rate to maintain a predetermined pump margin across the flow control valve.

A hydraulic system is provided for controlling one or more piston-cylinders of an implement. An implement valve includes at least one spool operable to transition between a neutral position and an open position. A variable displacement pump is operable to move a fluid from a reservoir into a supply conduit and to the at least one spool. A flow control valve, distinct and separate from the at least one spool is located in-line with the supply conduit between the variable displacement pump and the at least one spool, and is operable to simultaneously provide the fluid to the implement valve and to a bypass pathway. The bypass pathway extends from the flow control valve to the reservoir without intervening valving. Each of the at least one spool is operable to permit increased fluid flow to a corresponding piston cylinder of the implement when in the open position. The variable displacement pump is operable to vary a flow rate to maintain a predetermined pump margin across the flow control valve.

According to one embodiment, an actuator includes a plurality of channel members each including a first port into which fluid flows and a second port from which the fluid flows out. At least one of the channel members includes a different number of second ports from a number of first ports.