Browse Topic: Hydraulic equipment
As the automotive industry undergoes significant changes in the dynamic behavior of vehicles and increasing demand for rapid product design, accurate prediction of product performance in the early stages has become more crucial than ever in the competitive environment. Shim-stack-type hydraulic dampers are widely used in automotive parts for both internal combustion engine (ICE) vehicles and electric vehicles (EV). EVs are even more sensitive to damper performance as ICE, which is a major NVH source has been removed. However, the industry still faces challenges in obtaining accurate models of dampers due to their highly nonlinear hydro-mechanical behavior. Bleed slits in a shim-stack-type hydraulic damper play a key role in determining the blow-off characteristics of dampers, and therefore, accurate prediction of the blow-off characteristics is crucial in evaluating the damping performance of a vehicle. Bleed flow analyses are conducted at two levels: component level and assembly
Reducing weight from components and systems is a major trend in passenger vehicles to boost fuel efficiency and driving range - it's not a strategy typically associated with construction machinery and stationary applications. Liebherr Components contends that such off-highway applications also can benefit from utilizing lighter-weight components and has spent years developing the expertise and production capabilities to add them to its hydraulics portfolio. Liebherr recently revealed “hybrid” hydraulic cylinders - components made of steel but wrapped in carbon-fiber-reinforced plastic (CFRP) - that can be up to 50% lighter than traditional all-steel cylinders. Depending on the application and customer preference, the weight savings can increase operating speeds, allow larger attachments and booms, and raise payloads - or, as in road-going vehicles, reduce CO2 emissions and fuel consumption during operation, the company said.
This SAE Aerospace Recommended Practice (ARP) covers the design and installation requirements for hydraulic systems (up to 8000 psig [56 MPa]) for ground support equipment (GSE). This ARP is derived from AS5440, which provides hydraulic system requirements for aircraft. The recommendations herein are primarily intended for GSE that exchange hydraulic fluid with the aircraft, such as hydraulic service carts, rather than GSE with non-interfacing hydraulic systems. The GSE may be mobile, portable, or stationary.
This SAE Aerospace Standard (AS) provides general design and test requirements for a flat cut-off pressure compensated, variable delivery hydraulic pump for use in a civil aircraft hydraulic system with a rated system pressure up to 5000 psi (34500 kPa). NOTE: Hydraulic pumps may incorporate features such as a clutch in the input drive, which will not be covered by this standard.
This SAE Aerospace Information Report (AIR) provides basic information on the use of slipper seal sealing devices when used as piston (OD) and rod (ID) seals in aerospace fluid power components such as actuators, valves, and swivel joints, including: The definition of a slipper seal and the description of the basic types in use. Guidelines for selecting the type of slipper seal for a given design requirement are provided in terms of friction, leakage, service life, installation characteristics, and interchangeability.
Traditionally, agricultural sprayer machines were custom-built on a four-wheel chassis. These custom-built units were heavy, expensive, and not easily adapted to other farm applications. Sprayers are typically used to apply herbicides, insecticides, and fertilizer. Naturally, it would be more practical if a machine could be used for other functions such as tilling, loading, and baling.
Applies to hydraulic cylinders which are components of off-road self-propelled work machines defined in SAE J1116.
This document covers the general requirements for hydraulic aircraft jacks. It can be applied to tripod, unipod, and axle jacks that may be used on open ramp areas as well as in the aircraft hangar. Throughout this Aerospace Standard, the minimum essential criteria are identified by the key word “shall”. Recommended criteria are identified by use of the key word “should”. Deviation from recommended criteria should only occur after careful consideration and thorough service evaluation have shown alternate methods to provide an equivalent level of safety. The term “vertical load” throughout this Aerospace Standard is defined as the force imposed on the aircraft jack at the airframe jack point.
This SAE Aerospace Information Report (AIR) provides details of how to perform hydraulic system calculations using equations that incorporate the metric International System of Units (SI).
This SAE Aerospace Recommended Practice (ARP) specifies dimensional and physical requirements of tow bar connections to tractor and aircraft (see Figure 1). It is applicable to all types of commercial transport category aircraft tow bar. The purpose of this SAE Aerospace Recommended Practice (ARP) is to standardize tow bar attachments to airplane and tractor according to the mass category of the towed aircraft, so that one tow bar head with different shear levels can be used for all aircraft that are within the same mass category and are manufactured in compliance with AS1614 or ISO 8267.
Mobile hydraulic machines are the unrecognized stars of the world. Digging the channels, loading the piles, excavating at various altitude and varying ambient are extremely tough work a machine does only with the help of hydraulics. Reservoirs to store the hydraulic oil plays key role in accomplishing these jobs. Most of the reservoir compromises with their shape and aesthetic due to compactness of the machine. The hydraulic reservoir performs various duties, the primary and obvious job of the reservoir is to hold the hydraulic fluid and used to circulate into the actuators of the system via pumps and valves whereas reservoirs are also responsible for providing enough surface area for the cooling of the hydraulic fluid. Over the year, physical testing is the only way for evaluating the effectiveness of the hydraulic reservoir, however with advancement in numerical techniques, like Multiphase 3D CFD approaches, this issue can be easily addressed by virtual analysis much ahead of the
Applies to hydraulic cylinders which are components of Off-Road Work Machines defined in SAE J1116.
Applies to hydraulic seals used to seal the rods of hydraulic cylinders which are components of off-road self-propelled work machines defined in SAE J1116.
This SAE Aerospace Recommended Practice (ARP) provides definitions and background information regarding the physical performance and testing of electrohydraulic flow control and pressure control servovalves. This ARP also provides extensive guidance for the preparation of procurement specifications and for functional testing. NOTE: An example of a procurement specification is provided as Appendix A.
This work presents a new design of ventilation pillars in ventilated brake discs. The use of National Advisory Committee for Aeronautics (NACA) aerodynamic profiles is proposed. Of the references consulted, there is no standard or procedure that indicates how the pillars should be installed in the ventilated discs. Therefore, it is proposed using the Kaplan’s error triangles theory of turbo hydraulic machinery to have a geometrically orderly way of placing the NACA 66-209 profiles from the suction diameter to the discharge diameter. To validate this new design, a 1:1 scale acrylic disc model was constructed, and tests were conducted in water using the particle tracking velocimetry technique to characterize the water model. The water experiment was performed at test speeds of 35, 41, 48, and 54 rpm. From the experiment in water, it is possible to visualize the flow field from the suction diameter to the model discharge diameter and scale the results to the prototype in air. Being 54 rpm
This SAE Standard provides a uniform method to calculate the lift capacity of knuckle-boom log loaders and certain forestry equipment. It establishes definitions and specifies machine conditions for calculations. This document applies to knuckle-boom log loaders as defined in ISO 6814 and ISO 17591 and certain forestry equipment defined in ISO 6814 that have a rotating upper-structure such as feller bunchers, forwarders, harvesters, and behind the cab or rear-mounted knuckle-boom log loaders not having their own power supply. It does not apply to harvesters that are incapable of lifting a tree or log completely off the ground. This document applies to those machines that are crawler, rubber-tired, and pedestal or stationary mounted.
This test code describes tests for determining characteristics of hydraulic positive displacement pumps used on off-road self-propelled work machines as referenced in SAE J1116.
SAE J1273 provides guidelines for selection, routing, fabrication, installation, replacement, maintenance, and storage of hose and hose assemblies for hydraulic fluid-power systems. Many of these SAE Recommended Practices also may be suitable for other hoses and systems.
This document discusses the relative merits of the physical and chemical properties of hydraulic fluids in relation to the aerospace hydraulic system design, and the related materials compatibility. The discussion in this report applies both to hydrocarbon and phosphate ester based aircraft hydraulic fluids. In some cases, numerical limits are suggested, but, in general, the significance and effect of a property is noted qualitatively.
This SAE Information Report is primarily to familiarize the designer of hydraulic powered machinery with the necessity for oil filtration in the hydraulic power circuit, the degree of system cleanliness required, types of filtration and filters available, and their location and maintenance in the hydraulic circuit.
Communicate the process of accurately measuring sound power levels of positive displacement hydraulic pumps commonly used in ground vehicle steering systems. This recommended practice defines the pump mounting (pulley, belt tension, isolation), operating conditions (fluid, speed, temperature, pressure), room acoustics, instrumentation, noise measurement technique and data acquisition setup to be used. Included are recommendations for test sample size, and format for data presentation/reporting.
This SAE Aerospace Recommended Practice (ARP) provides a procedure for obtaining filter patch test samples from the following types of aerospace non-rotating hydraulic equipment: Mechanical/Hydraulic Units Electro/Hydraulic Units Pneumatic/Hydraulic Units
This standard covers mobile hydraulic excavator controls and the specific arrangement and direction of motion for the primary controls. This standard applies to mobile hydraulic excavators as described in ISO 7135—Earthmoving machinery—Hydraulic excavators—Terminology and commercial specifications, and ISO 6165—Earthmoving machinery—Basic types—Vocabulary.
This SAE Aerospace Standard (AS) shall be used in conjunction with AMS4946 to provide requirements for qualification testing and for qualified products listing (QPL) and qualified manufacturer listing (QML) for Ti-3Al-2.5V cold worked and stress relieved hydraulic system tubing. The basic tubing shall comply with the requirements of AMS4946.
This SAE Aerospace Standard (AS) defines the requirements for polytetrafluoroethylene (PTFE) lined, metallic reinforced, hose assemblies suitable for use in aerospace hydraulic, fuel, and lubricating oil systems at temperatures between -67 °F and 450 °F for Class I assemblies, -67 °F and 275 °F for Class II assemblies, and at nominal pressures up to 1500 psi. The hose assemblies are also suitable for use within the same temperature and pressure limitations in aerospace pneumatic systems where some gaseous diffusion through the wall of the PTFE liner can be tolerated. The use of these hose assemblies in pneumatic storage systems is not recommended. In addition, installations in which the limits specified herein are exceeded, or in which the application is not covered specifically by this standard, for example oxygen, shall be subject to the approval of the procuring activity.
This Recommended Practice is derived from the FMVSS 105 vehicle test and applies to two-axle multipurpose passenger vehicles, trucks, and buses with a GVWR above 4540 kg (10000 pounds) equipped with hydraulic service brakes. There are two main test sequences: Development Test Sequence for generic test conditions when not all information is available or when an assessment of brake output at different inputs are required, and FMVSS Test Sequence when vehicle parameters for brake pressure as a function of brake pedal input force and vehicle-specific loading and brake distribution are available. The test sequences are derived from the Federal Motor Vehicle Safety Standard 105 (and 121 for optional sections) as single-ended inertia-dynamometer test procedures when using the appropriate brake hardware and test parameters. This recommended practice provides Original Equipment Manufacturers (OEMs), brake and component manufacturers, as well as aftermarket suppliers, results related to brake
This SAE standard includes hydraulic backhoes which have no more than 190 degrees of rotational swing and are mounted on wheeled tractors and crawler tractors. Illustrations used are not intended to include all existing commercial machines or to be exact descriptions of any particular machine. The illustrations have been chosen to describe the principles to be used in applying this standard.
This SAE Aerospace Recommended Practice (ARP) provides recommendations for design and test requirements for self-displacing hydraulic accumulators.
This SAE Aerospace Standard (AS) specifies the general requirements for hydraulic system reservoirs that are installed in commercial and military aircraft and helicopters and also in missile hydraulic systems. This document includes design, test (production and qualification) criteria for various types of reservoirs. Appendix A provides information on hydraulic fluid volume requirements and reservoir sizing. This document also provides a basis for the Procurement Specification to completely define individual reservoir requirements.
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