An example valve assembly includes a first workport fluidly coupled to a first actuator; a second workport fluidly coupled to the first actuator; a third workport fluidly coupled to a second actuator, wherein the third workport is fluidly coupled to the first workport via a first fluid passage; a fourth workport fluidly coupled to the second actuator, wherein the fourth workport is fluidly coupled to the second workport via a second fluid passage; and a spool axially movable in a bore within the valve assembly, wherein when the spool is shifted axially in a first axial direction, pressurized fluid is provided to the first workport and to the third workport via the first fluid passage, and when the spool is shifted axially in a second axial direction opposite the first axial direction, pressurized fluid is provided to the second workport and to the fourth workport via the second fluid passage.

A fluid pressure circuit includes a directional switching valve arranged between a fixed displacement pump and a fluid pressure actuator and configured to switch a flow passage for a pressurized fluid, an accumulator arranged in a branch flow passage branched from a connection flow passage that connects the fluid pressure actuator and the directional switching valve, an accumulator flow control valve arranged between the connection flow passage and the accumulator, and a pump flow control valve arranged between the fluid pressure actuator and the fixed displacement pump and configured to variably divert a flow rate of the pressurized fluid discharged from the fixed displacement pump into a first system including the tank and a second system including the fluid pressure actuator.

A hydraulic machine includes: a power source; an assist motor including comprising an inlet port and an outlet port and assisting a torque of the power source; a tank; a collection line which is connected to the inlet port and allows a fluid to flow to the inlet port; a first return line which is connected to the tank and allows the fluid to flow to the tank; a self-priming line which connects the first return line to the inlet port and allows the fluid to flow from the first return line to the inlet port; and an anti-cavitation line which connects the outlet port to the self-priming line and allows the fluid to flow from the outlet port to the self-priming line.

A hydraulic system for a cyclically operating shaping machine includes at least one hydraulic drive unit for cyclically driving a component of the shaping machine at a start time; at least one pump; and at least one hydraulic accumulator which can be discharged for driving the at least one hydraulic drive unit and which can be charged up by operation of the at least one pump. An open-loop or closed-loop control unit is also provided for control of the at least one pump. The open-loop or closed-loop control unit is adapted to operate the at least one pump continuously until the start time of the at least one hydraulic drive unit to charge up the at least one hydraulic accumulator until the start time of the hydraulic drive unit.

A pressure accumulator includes an accumulator housing having first and second ports for receiving first and second pressure mediums, respectively, a movable separating element subdividing an interior of the accumulator housing into at least first and second working spaces, the first working space accommodating the first pressure medium and the second working space accommodating the second pressure medium, wherein the first port is in fluid communication with the first working space and the second port in fluid communication with the second working space. At least one sensor is operatively coupled to the first working space for measuring at least one characteristic of the first working space, and a gas generator is operative to generate a gas from ambient air, the gas generator including an outlet for outputting the generated gas, the outlet in fluid communication with the first port. A controller is operatively coupled to the at least one sensor and the gas generator, the controller configured to calculate an amount of gas in the first working space based on the at least one characteristic and upon the calculated amount of gas in the first working space being below a first threshold level, generate a command to introduce gas from the gas generator into the first working space.

A hydraulic machine includes a tank; a working device including a boom; a boom cylinder which operates the boom and has a large chamber and a small chamber; a floating hydraulic circuit connected to the large chamber, the small chamber, and the tank so as to enable the large chamber, the small chamber, and the tank to communicate with each other; and an operator input device for receiving, from a driver, a request for turning on or turning off the floating hydraulic circuit. In the case of a boom down operation for lowering the boom, it is determined whether the working device floats in the air, and when it is determined that the working device floats in the air, the floating hydraulic circuit can be turned off, even if the request for turning on the floating hydraulic circuit is input to the operator input device.

An active accumulator system which automatically adjusts or adapts the charge pressure or volume of an accumulator to maintain an optimal charge pressure or volume of the accumulator may provide optimal operation of a pump. An active accumulator system may comprise a flow line coupled to a pump, wherein a fluid flows through the flow line to the pump, an accumulator coupled to the flow line, a transducer coupled to the pump, wherein the transducer detects a parameter of the pump at an inlet of the pump, and a controller coupled to the transducer and the accumulator, wherein the controller receives the parameter, and wherein the controller regulates air flow to the accumulator such that the accumulator is adjusted to an optimal charge pressure based at least in part on the parameter.

An active accumulator system which automatically adjusts or adapts the charge pressure or volume of an accumulator to maintain an optimal charge pressure or volume of the accumulator may provide optimal operation of a pump. An active accumulator system may comprise a flow line coupled to a pump, wherein a fluid flows through the flow line to the pump, an accumulator coupled to the flow line, a transducer coupled to the pump, wherein the transducer detects a parameter of the pump at an inlet of the pump, and a controller coupled to the transducer and the accumulator, wherein the controller receives the parameter, and wherein the controller regulates air flow to the accumulator such that the accumulator is adjusted to an optimal charge pressure based at least in part on the parameter.

The present disclosure shows a hydraulic regeneration circuit for a hydraulic cylinder that enables multiple extension speeds for the cylinder even while using fixed displacement pumps. The regeneration circuit uses the expelled fluid to drive a hydraulic pump/motor combination to create 4 or more speeds, as opposed to the 2 speeds typical in regeneration circuits. By using directional flow control valves, the fluid can be combined in such a way that the operator can choose a speed multiplier for the hydraulic cylinder to operate at.

Systems, methods, and apparatuses for operating a machine using energy stored in a compressed gas are disclosed. Energy stored in the compressed gas may be used to pressurize a fluid, such as transmission fluid, and the pressurized fluid may be used to effectuate an operation of the machine, such as a transmission, and the operation of the machine may involve shifting of the transmission. The gas may be compressed by a first fluid using a second fluid, and the two fluids are be prevented from being mixed together.