Some embodiments of the disclosure provide an advance and retreat automatic control method based on hydraulic sensing conversion and an advance and retreat automatic control system based on hydraulic sensing conversion, which includes an automatic advance and retreat device based on hydraulic sensing conversion, a motor, an oil cylinder, and/or an electric generator. When the digging motor encountered an overlarge resistance force, a pressure on the digging motor is instantaneously increased and exceeds a setting pressure value, hydraulic oil enters a hydraulic operated directional valve and pushes a valve rod to make the walking motor is reverse and retreat, an ultrahigh pressure state of the digging motor is released to restore to a normal pressure value to make reciprocated impact, the valve rod of the hydraulic operated directional valve is reset, and the walking motor is forwards rotated for advancing.

A hydraulic intensifier and/or booster (HIB) for transforming an incoming hydraulic pressure at a relative low-pressure to an amplified outgoing hydraulic pressure at a relative high-pressure. The HIB comprising a hydraulic motor and an intensifying mechanism, possibly a hydraulic screw pump mechanism, wherein the hydraulic motor being arranged from the incoming hydraulic pressure to output power. The intensifying mechanism being arranged to receive the outputted power from the hydraulic motor and transform it to linear power of a piston and via the piston being arranged to build the amplified outgoing hydraulic pressure.

A hydraulic intensifier and/or booster (HIB) for transforming an incoming hydraulic pressure at a relative low-pressure to an amplified outgoing hydraulic pressure at a relative high-pressure. The HIB comprising a hydraulic motor and an intensifying mechanism, possibly a hydraulic screw pump mechanism, wherein the hydraulic motor being arranged from the incoming hydraulic pressure to output power. The intensifying mechanism being arranged to receive the outputted power from the hydraulic motor and transform it to linear power of a piston and via the piston being arranged to build the amplified outgoing hydraulic pressure.

A device having a hybrid hydraulic-electric architecture includes a hydraulic pump/motor having first and second ports, and an electric motor. The device is configured to connect to two or more pressure rails, each pressure rail containing hydraulic fluid at a different pressure than the other pressure rails. A flow of hydraulic fluid from one of the pressure rails is driven through the hydraulic pump/motor, and a pressure difference exists between the first and second ports. The electric motor is configured to control a flow rate of the flow of hydraulic fluid and/or the pressure difference.

A hydraulic actuator (1) is disclosed comprising a cylinder housing (2), a piston (5) with a piston rod (6) being displaceably arranged inside the cylinder housing (2) and a pressure amplifier (10) comprising an inlet section (18) with a pressure inlet port (20), an active section (19) with a high pressure outlet port (22), a low pressure chamber (32) and a high pressure chamber (38a). It is an objective of the invention to provide a hydraulic actuator (1) with a modular pressure amplifier (10). To this end, the inlet section (18) is arranged inside the piston rod (6), and wherein the low pressure chamber (32) is stationarily arranged relative to the inlet section (18).

In a hydraulic shield support system, a plurality of pressure intensifiers are respectively provided for a plurality of hydraulic props. Each pressure intensifier is operated to increase a system pressure to an increased pressure for supplying fluid at the increased pressure to a pressure chamber of the associated hydraulic prop. The plurality of pressure sensors measure the pressures of the fluid supplied to the respective hydraulic props. A control unit sets a plurality of desired pressures for the plurality of hydraulic props, and stops operation of the respective pressure intensifiers when the set desired pressure has been reached.

A hydraulic actuator arrangement (1) is described comprising a hydraulic actuator having a pressure chamber (2), a cylinder (3) in a cylinder housing (4), and a piston (5) connected to a piston rod, a hydraulic pump (7) connected to the pressure chamber (2) and an electric motor (8) driving the hydraulic pump (7), wherein the pump (7) and the motor (8) are arranged within the actuator. Such an actuator arrangement should have many application possibilities. To this end, a hydraulic pressure amplifier (10) is arranged between the hydraulic pump (7) and the pressure chamber (2).

A hydraulic actuator (1) is disclosed comprising a cylinder housing (2), a piston (5) with a piston rod (6) being displaceably arranged inside the cylinder housing (2) and a pressure amplifier (17) comprising an inlet section (18) with a pressure inlet port (20), an active section (19) with a high pressure outlet port (22), a low pressure chamber (32) and a high pressure chamber (38a). It is an objective of the invention to provide a hydraulic actuator (1) with a modular pressure amplifier (17). To this end, the hydraulic actuator (1) comprises a cartridge pressure amplifier (10) comprising a sleeve (10a) being arranged at least partially inside the piston rod (6), and wherein the pressure amplifier (17) is stationarily arranged inside the sleeve (10a).

A device having a hybrid hydraulic-electric architecture includes a hydraulic pump/motor having first and second ports, and an electric motor. The device is configured to connect to two or more pressure rails, each pressure rail containing hydraulic fluid at a different pressure than the other pressure rails. A flow of hydraulic fluid from one of the pressure rails is driven through the hydraulic pump/motor, and a pressure difference exists between the first and second ports. The electric motor is configured to control a flow rate of the flow of hydraulic fluid and/or the pressure difference.

A pneumatic unit for a hydropneumatic pressure booster has a system line that leads from a compressed air inlet to a compressed air outlet. A bypass line runs parallel to the system line and it is connected to the system line via first and second compressed air switches. A compressed air reservoir is connected in the bypass line, and a pressure intensifier is connected in the region between the first compressed air switch and the compressed air reservoir. The pneumatic unit makes available to the pressure booster a sufficiently high pneumatic pressure for carrying out at least one operational step of a connected hydraulic tool, even in the case of a pressure decrease or pressure failure in the supplying pneumatic line. For that purpose, the second compressed air switch is configured for switching the compressed air flow between the system line and the bypass line.