A noise reduction apparatus, an aircraft, and a noise reduction method capable of increasing the amount of noise reduction are provided. The noise reduction apparatus 1 includes a porous plate 2 disposed to face a fluid flow, the porous plate 2 including a bend region 5 bent toward an upstream side of the fluid flow. The bend region 5 is provided at the end portion 6 of the porous plate 2, and has a concave R-shape on an upstream side of the fluid flow.

Disclosed are a damping system for a movable arm of a loading machine and an operation machinery, which comprise a multi-way valve, a movable arm oil cylinder, a movable arm damping valve, and a damping lock. The multi-way valve comprises a movable arm valve core and a bucket valve core, a first movable arm oil port of the movable arm valve core communicates with a rod cavity of the movable arm oil cylinder, a second movable arm oil port of the movable arm valve core communicates with a rodless cavity of the movable arm oil cylinder, the rod cavity of the movable arm oil cylinder communicates with the movable arm damping valve, the rodless cavity of the movable arm oil cylinder communicates, via the damping lock, with the movable arm damping valve; a switching oil port of the damping lock communicates with an unloading position of the bucket valve core.

A hydraulic system (600) and method for reducing boom dynamics of a boom (30), while providing counter-balance valve protection, includes a hydraulic actuator (110), first and second counter-balance valves (300, 400), first and second control valves (700, 800), and first and second blocking valves (350, 450). A net load (90) is supported by a first chamber (116, 118) of the hydraulic actuator, and a second chamber (118, 116) of the hydraulic actuator may receive fluctuating hydraulic fluid flow from the second control valve to produce a vibratory response (950) that counters environmental vibrations (960) on the boom. The first blocking valve prevents the fluctuating hydraulic fluid flow from opening the first counter-balance valve. The first blocking valve may drain leakage from the first counter-balance valve.

Presented herein are systems and methods for attenuating certain pulsations in a hydraulic system comprising a pump and a hydraulic actuator. In certain aspects, an accumulator comprising an internal volume that is divided into a working chamber and a contained chamber may be utilized to at least partially attenuate propagation of certain pulsations in the system. The working chamber may be fluidically coupled to the pump via a first flow path and fluidically coupled to a chamber of the actuator via a second flow path. The system may be designed such that a first inertance of the first flow path is greater than a second inertance of the second flow path. Additionally or alternatively, the system may be designed such that a resonance associated with the first inertance and a compliance of the accumulator may occur at a resonance frequency of less than 90 Hz.

A method for operating a hydraulic valve of a hydraulic device of a motor vehicle transmission device, wherein an actuating current of the hydraulic valve is superposed with a modulation alternating current in order to adjust a shaking vibration of the hydraulic valve by a control device, wherein a deviation between an actual pressure resulting from the actuating current and a setpoint pressure determined as a function of the actuating current is determined for the hydraulic device by means of an electronic computing device, and an amplitude and/or a frequency of the modulation alternating current is increased as compared to a starting value equalizing a hysteresis of the actual pressure relative to the setpoint pressure, as a function of a tolerance range being exceeded by the determined deviation.

A twin chamber air dryer for a pneumatic system of a commercial vehicle comprises: a supply inlet port, a supply outlet, a compressor control outlet, and an exhaust outlet; a first desiccant cartridge and a second desiccant cartridge, to be operated alternately; a toggling valve assembly for switching between the first and second desiccant cartridges; a pneumatically controlled purge valve switchable between a blocking basic position and an activated position; and a solenoid valve assembly. The solenoid valve assembly comprises a directional control solenoid valve for receiving an electrical direction control signal and controlling the toggling valve assembly, a regeneration solenoid valve for receiving an electrical regeneration control signal and providing pressurized air in regeneration phases of the desiccant cartridge, and a governor solenoid valve for receiving an electrical governor control signal and controlling the purge valve and a compressor mode.

This reservoir tank is provided with a reservoir body formed in the shape of a hollow box inside which a hydraulic fluid is stored, and is connected to a vehicle master cylinder in such a way that brake fluid flows into and out of the same. The reservoir body is provided with a top plate portion formed in the shape of a plate. A flow path portion having one or a plurality of flow paths formed in a serpentine fashion and opening downward in a vertical direction is provided in a protruding manner on an inner wall surface of the top plate portion, and a slit is provided on a downstream side of the flow path.

The disclosure relates to an electronic pump that can be used in a motor vehicle, particularly for generating hydraulic fluid flow for steering and braking, or to perform auxiliary functions such as dump bodies for garbage trucks or landscape trucks. Methods of operating the system and manufacturing the system are also provided.

A tail-rotor vibration dampener system for an aircraft is provided. The system includes a fuselage and an open rotor assembly including a powerplant and a set of rotor blades. The system further includes at least one actuator unit connecting the open rotor assembly to the fuselage. The actuator unit includes a hydraulic actuator controlling a position of the open rotor assembly in relation to the fuselage and a dampening device operable to cancel a vibration emanating from the open rotor assembly. The system further includes a computerized vibration dampening controller, including programming to determine a frequency of the vibration emanating from the open rotor assembly and control the dampening device to cancel the vibration emanating from the open rotor assembly based upon the frequency.

Hydraulic systems and methods for reducing the propagation of flow and/or pressure pulsations within a hydraulic system are described. In one embodiment, a hydraulic system may include a hydraulic device and a differential buffer fluidly connected to the hydraulic device. The differential buffer may include a piston that is exposed to pressure pulsations that propagate along separate flow paths and that are at least partially out of phase with one another. Corresponding displacement of the piston due to the out of phase pulsations may at least partially mitigate propagation of the pulsations within the hydraulic system downstream from the differential buffer.