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Auxiliary Components
Published in John S. Cundiff, Michael F. Kocher, Fluid Power Circuits and Controls, 2019
John S. Cundiff, Michael F. Kocher
Accumulators are used in hydraulic systems to provide a source of pressurized fluid. They may be needed in emergencies, such as when power to the pump is interrupted. In some system designs, they may be used to allow selection of a less expensive pump with a smaller displacement. Examples of these situations include systems with work cycles involving times with high flow requirements and times with low flow requirements, or with work cycles that include significant idle times. The reader may want to review Section 3.4.
Hydraulic Power Generation
Published in Qin Zhang, Basics of Hydraulic Systems, 2019
Hydraulic pumps are the energy conversion devices used to convert mechanical power into hydraulic potential energy, driving various hydraulic actuators to perform work. One fundamental requirement in designing a hydraulic system is to provide sufficient power to those actuators to do the designated work. In general, the amount of power delivered by a hydraulic pump is determined by the flow rate and the fluid pressure. As discussed in the previous section, the amount of flow a pump can deliver is determined by its displacement and operating speed, but the pressure is determined by the total load applied on the system.
Force-System Resultants and Equilibrium
Published in Richard C. Dorf, The Engineering Handbook, 2018
Hydraulics deals with the principles that govern the behavior of liquids at rest and in motion. This is the study of the mechanics of water and its control by man. Hydraulics deals with pressurized systems and open channel flow, and includes principles of pressure and force, energy theorem, flow calculations and measurement, friction losses, pumps, and pumping applications.
Regenerative hydraulic SUSPENSION: Numerical model and Evaluation of Energy Harvesting Potential using bond graphs
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Vjekoslav Tvrdic, Srdjan Podrug, Vjekoslav Damic, Milan Perkušić
Hydraulic accumulators are used to store fluid energy during the operation of a hydraulic system. There are different types of accumulators, but the most used are hydraulic with gas (nitrogen) filled accumulators. Hydraulic accumulators consist of two chambers that are usually separated by a piston or diaphragm. The upper chamber of the accumulator is filled with gas and the hydraulic fluid is introduced into the lower chamber through a check valve at the bottom of the structure. If there is no fluid in the accumulator and the gas chamber is empty, the hydraulic check valve in the lower chamber is fully open. To prepare for operation, the hydraulic accumulator is pre-charged to relative pressure and the diaphragm is stretched to fill all available space in the device. In this process, the check valve at the bottom of the accumulator closes. Hydraulic accumulator pre-charge pressure is usually taken at 80% of the minimum fluid operating pressure.
Prediction of ultimate bearing capacity of circular foundation on sand layer of limited thickness using artificial neural network
Published in International Journal of Geotechnical Engineering, 2021
Barada Prasad Sethy, Chittaranjan Patra, Braja M. Das, Khaled Sobhan
Load to the foundation was applied by a special design loading unit. The loading machine consists of three units: (a) the electrical control panel, (b) hydraulic power pack, and (c) loading device. The loading device is a combination of a beam, four cylinders, four supporting columns, and a base. The hydraulic cylinder is the device that converts fluid energy to linear mechanical force and motion. It converts fluid energy to an output force in a linear direction for executing different jobs. The capacity of the hydraulic cylinder in the universal static loading set- up was 100 kN. The load could be applied to the model foundation in the range of 0–100 kN with an accuracy of 1 N. Forward and backward movement of the cylinder could change the inclination of the load. The inclination of the load remains intact throughout the testing period by the provision of check valve. Dial gauges placed on two sides of the model foundation measured the settlement along the centerline of the model foundation. The arrangement of the test set-up conducted in the laboratory is shown in Figure 4.
Trends in hydraulic actuators and components in legged and tough robots: a review
Published in Advanced Robotics, 2018
Koichi Suzumori, Ahmad Athif Faudzi
Hydraulic pumps convert mechanical energy, such as the rotations of motors or engines, to fluid energy. Hydraulic pumps such as piston pump, vane pump, gear pump, screw pump, and reciprocal pumps are among the types of pumps used in conventional hydraulics [40]. Recent development is mainly focused on piston, vane and gear pumps where these types of pumps are suitable for robotics and mobile hydraulics application. Small and compact pump using piezohydraulic structure was presented by Valdovinos et al. [134]. They demonstrate a proof-of-principle compact (centimeter size) piezo hydraulic pump that can produce useful mechanical work driven at frequencies in the kilohertz range compared with other piezohydraulic pumps. Tokyo Tech. and KYB Co. Ltd have developed a miniature piston pump [39] to be used in a new power pack as shown in Figure 11. The design is possible for both stationary and mobile hydraulic tough robots.