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Technical Paper

Rapid Prototyping Shortens Hydraulic Component Development Time

1995-09-01
952109
A few years ago hydraulic fluid power component manufacturers had the luxury of long lead times to develop new products. In today's competitive global market, pump and valve design engineers must be able to shorten development lead times and get new, less costly products to production in order to satisfy customer demands. This paper describes how one fluid power component manufacturer uses rapid prototyping technology to speed up the development cycle by making: fit and form models, design evaluation test samples, and tooling for prototype castings.
Technical Paper

Using Finite Element Analysis and Metallographic Analysis to Understand Field Forces on an Industrial Head Gasket

1995-02-01
950321
A major concern in head gasket reliability of an industrial diesel engine is flange cracking. This paper will discuss head gasket flange cracking and the head gasket joint environment as they relate to an industrial diesel engine head gasket joint. The paper will discuss metallographic and finite element analysis of head gasket field failures. The metallographic analysis will discuss the evaluation of production, assembled, laboratory tested, and field tested gaskets. The above will give head gasket designers and engine manufacturers insight into the industrial head gasket joint environment. The metallographic work will explain the method of creating micro sections as well as micro section measurements to aid in the understanding of the head gasket loading.
Technical Paper

Hydraulic Safety Valve Design Using PC Simulation

1996-08-01
961835
In today's global fluid power industry, successful hydraulic component manufacturers must utilize technical resources to maintain a competitive edge. When designing new products, past practice required an understanding of engineering theory and reliable and accurate lab and field testing of new products, but today's designers have a new tool at their disposal. Personal computer based software can be used to model and simulate individual hydraulic components or entire systems before prototypes are available for design and performance evaluation. This paper discusses the design of a hydraulic safety valve and how PC simulation was used to design and analyze valve performance during the design process.
Technical Paper

Heat Generation from Hydraulic System Losses in Refuse Packers

1996-08-01
961836
Heat generated in hydraulic systems can be responsible for reduced life of equipment. Current Industry trends look to load-sensing variable-displacement pumps and closed-center valves to combat the problem. A comparison is made between the load-sensing variable-displacement pump with closed-center control valves and the fixed-displacement pump (both wet and dry valve types) with open-center control valves, to determine the heat generation tradeoffs. The use of tanks, lines and cylinders as a heat radiator is considered. Heat generated by high-pressure leakage of driven members is addressed. The primary focus of this paper is on packer and body hydraulics of refuse trucks.
Technical Paper

Reduced Instruction Set Computers Versus Complex Instruction Set Computers for Gasket Finite Element Analysis

1992-09-01
921706
The intent of this paper will be to address the level of performance and cost of the various complex instruction set computers (CISC-80X86) versus the reduced instruction set computers (RISC). The original concept of reduced instruction set computers will be explained. The above information will be contrasted with how the second generation system functions. Once the operations are established, a discussion of operating performance as related to several types of benchmarks will be cited. A typical FEA model will be used as the final benchmark to determine realistic performance versus speed (wall clock time). The final comparison will be of cost.
Technical Paper

Torsionally Resilient Drive Lines

1960-01-01
600019
THE INCREASED use of midship-mounted transmissions in large equipment has emphasized the need for a torsionally resilient connection from the engine to reduce vibration transfer. To increase the torsional flexibility needed in these systems, the spring rate of the system must be reduced by such constructions as a flexible coupling, a spring-loaded damper, or a rubber torsional spring. This paper discusses these systems, emphasizing rubber springs. Some advantages of such a drive are: it provides an amplitude limitation with impact loads and a cushion to reduce noise and prevent clattering and contacts noises on parts with backlash, it smooths out transition periods to reduce loads on bearings and gears, its clamping characteristics can be adjusted by various rubbers, and its rubber cushion provides a degree axial flexibility.*
Technical Paper

REAR AXLES Today Tomorrow

1958-01-01
580038
ON THE basis of laboratory and field tests of passenger-car and light-truck rear axles, the authors conclude: 1. The capacity of present axles can be increased, without increasing axle size, when greater load-carrying antiwear and antiscore lubricants are available. 2. Gear noise will always be a major problem because axle gears are operating at varying speeds and loads whenever a car is in motion. Many gear noise problems can be overcome by proper tooth development and by testing in the actual car model under which the axle will be used. 3. The only reliable basis for torque-capacity rating is the tractive effort (wheel-slip torque). 4. The limited-slip type of differential will eventually become standard equipment on all passenger cars, if only to improve car handling and stability during high-speed driving under varying traction conditions.
Technical Paper

Vehicle Performance Prediction

1965-02-01
650623
This paper describes a method of vehicle performance prediction which adapts readily to digital programming. A prime mover which may be a gas turbine or a reciprocating internal combustion engine, a hydraulic torque converter, and/or a mechanical transmission, comprising the vehicle drive train, are transformed into numerical equivalents. The performance prediction itself is in three major parts, namely, the engine-converter compatibility, the converter range performance, and the lockout or direct drive performance. The computer transforms the engine data into equation form by curve fitting; predicts the optimum shift point as the intersection of the net tractive effort in converter drive with net tractive effort in direct drive; calculates; stores; interpolates; and prints a complete set of data.
Technical Paper

Determining Magnitudes of Axle Gear Noise

1963-01-01
630166
A simple and basic laboratory test is described which may be used to evaluate and compare axle noises in a passenger car. In this method, a number is assigned to the magnitude of a given noise at any given frequency through a complete range of speed and load conditions during typical vehicle operation. A chassis dynamometer is used to simulate road conditions, and various pickup and recording instrumentation are employed to record the objectionable noises under different operating conditions and speeds.
Technical Paper

Accelerated Testing of Multi-Layer Steel Cylinder Head Gaskets

2000-03-06
2000-01-1188
Accelerated testing techniques for cylinder head gaskets have become absolutely necessary because of developments at engine manufacturers including: shorter engine development times, high costs of vehicle and dynamometer testing, new material generations for engine components, and new engine generations and longer engine life This paper will describe two accelerated test methods for Multi-Layer Steel (MLS) cylinder head gaskets and will discuss the most important parameters which influence MLS cylinder head gasket functional performance. We will describe how these parameters have been duplicated in the laboratory using the accelerated tests: the Bending Simulator and the Hydraulic Pulsator. The test method results have been confirmed based on detailed metallurgical analysis of MLS gaskets; comparing field (dynamometer and vehicle) tested gaskets to those gaskets evaluated on accelerated tests.
Technical Paper

Microstructure and Mechanical Properties of Welded Thermoplastics

2004-03-08
2004-01-0732
Thermoplastics have been used increasingly for automobile components for both interior and under-the-hood applications. The plastic parts are made through various molding process such as compression molding, injection molding and blow molding. For parts with large or complicated geometry, small portions of the part may have to be molded first, then joined together using a welding process. The welded regions usually exhibit inhomogeneous and inferior mechanical performance compared to the bulk regions due to the differences in thermal history. The microstructures and mechanical properties of welded thermoplastics have been examined using hot-plate welded polyethylene. The specimens are prepared at various thermal conditions to simulate the real welding process. The thermal properties in welds are monitored using DSC (Differential Scanning Calorimetry) and the crystallinities are calculated.
Technical Paper

Spatial Transmissibility of Plastic Cylinder-Head Covers

2005-04-11
2005-01-1515
The transmissibility technique has been traditionally used for evaluating the NVH performance of isolated, rigid structures such as the elastomer mount isolated automobile engine. The transmissibility quantity provides information on how a structure reduces vibration as subjected to dynamic loading and thereby attenuates noise. In the present study, the transmissibility is applied to a non-rigid, plastic structure - the engine cylinder-head cover module. The cover module includes primarily a thin, plate-like cover and the elastomer isolation system. At low frequencies, the cover will behave as a rigid mass and thus display a major peak at its resonant frequency. At high frequencies, the cover will vibrate as a flexible panel and thus display multiple peaks with magnitudes differing from point to point across the cover surface. As a result, the transmissibility calculated would have a spatial resolution, called the spatial transmissibility.
Technical Paper

Variability of Test Specimens Used for Evaluating Light Duty Automotive Filter Seal Materials

1999-03-01
1999-01-0001
Quality control and materials development of cellular polyurethane foam used in light-duty automotive air filter seals rely on measurement of mechanical and physical properties such as tensile strength, elongation, compression set, specific gravity, and durometer hardness. These properties are typically measured on specimens cut from slabs formed in preheated closed molds. However, these slabs are nonuniform in specific gravity, and property measurements vary with location within a slab. The effect of sampling location on mechanical and physical properties is discussed.
Technical Paper

Analysis of an Automotive Driveline with Cardan Universal Joints

1995-02-01
950895
A detailed methodology is presented in this paper for a complete assessment of various forces, torques, and kinematic effects due to universal joint angularities and shaft yoke phasing. A modular approach has been adopted wherein constitutive equations represent each of the key elements of a driveline namely the driveshaft, coupling shaft, universal joint, and the transmission/axle shafts. Concentrated loads are used wherever loads are being transferred between the elements of a driveline. Local matrices are developed for the equilibrium of the respective driveline members. The local matrices are then assembled into a global matrix and solved for the kinematic state of the complete driveline. A 6x15 matrix has been developed to represent a general shaft in the system and a 6x10 matrix has been developed for a universal joint cross. This gives us a complete picture of all the loads on all driveline members.
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