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Diesel engines of the future will be the designer’s response to government regulation, economic restrictions and technological advances. This optimization process will demand adaptability and responsiveness to accelerating change in the business environment. Success will be determined by the degree of understanding of the various interactions.

Recently a demand for maintenance-free is increaing for mechanical components. We have already developed spherical plain bearings fitted with liners for railroad vehicles, which are now used in such places as anti-rolling equipments or longitudinal dampers in the vehicles for The New Tokaido Line. On the other hand, in construction machines or the like, development of a spherical bearing with high impact strength, resistance to high contact pressure and high resistance against muddy water is demanded. Investigations into anti-wear performance as well as creep resistance of various liner materials were made. It was found that polyimide resin with some fillers is the most superior.

Rolling bearings of standardized dimensions have proven to be reliable, long-lived structural components in all types of industry. Improved production methods and progressing knowledge in the fields of steel melting and heat treatment of rolling bearing steel resulted in a steady increase of the capacity of rolling bearings. This development is also reflected by the higher load ratings published recently. The new and advanced development of entire bearing series as well as the development of special bearings made to specifications are of equal importance. Such specially designed bearings opened up many modern and advanced fields of application, for example in space exploration and offshore technology. It can be said that, to date, the rolling bearing technology has fulfilled all requirements. In many cases the use of rolling bearings has resulted in economical overall designs and constructions.

Bearing damage mechanisms resulting from non-fatigue modes such as contamination, lack of lubrication, misalignment and improper handling are discussed. Included is also a discussion of fatigue modes of bearing damage. Tapered, cylindrical and ball bearings are incorporated into the discussion.

Since 1975 GLI Corporation has designed and supplied microprocessor based remote control systems for underground coal and hard rock mining equipment. Earth moving vehicles can use this technology as it exists today so long as the vehicle does not require more than six proportional, and 15 on/off controls.

The introduction of microcomputer technology into the industrial and consumer marketplaces has contributed to a significant growth in product efficiency, utility, reliability, and performance. Combining the intelligence of the microcomputer with the muscle of hydraulics has now greatly enhanced the creativeness of mobile equipment design. Significant strides have already been made with hydraulic excavator applications. Additional excavator advancements are in progress with a number of lattice boom and hydraulic crane developments soon to be accomplished. These current and proposed applications provide the basis for the topic of discussion.

Chromium and chromium-molybdenum carburizing steels are widely used for small- and medium- sized rolling bearings or gears, in Japan. Using a cylinder-to-ball type rolling contact fatigue rig, influence of various material factors such as chemical compositions, oxygen content, retained austenite and grain size in 1 % chromium carburizing steel was investigated. Life level of 1 % chromium steel has been increased gradually since 1968 when the test began. The increase in life level is mainly due to reduction in oxygen content by the improvement of steel-making technique. Manganese content increases the life and 1 % Cr steel with 1 % Mn has high reliable life. Prior austenite grain size does not seem to influence the rolling contact fatigue life.

A method for the analysis of a damaged bearing is described. An emphasis is placed on obtaining complete and accurate application information; conducting a thorough visual examination; making physical measurements as necessary; and conducting metallurgical tests. The method has been used for tapered roller bearings as well as a variety of other components of various steel types and processing histories.

The contact fatigue life of a roller thrust bearing depends on the roller load distribution, which is dependent on the shape of the raceway surfaces under load. This presentation will show a finite element method of calculating the deflections of a partially backed up thrust race with nonuniform loading. This loading can be the result of an eccentric thrust load, or nonparallel raceway surfaces. A brief discussion of the theory will be presented along with a typical application.

A cartridge type pivotal pin and bushing joint has been patented and is being tested and refined both in the laboratory and on construction machinery. It features “dry lubricated” (Teflon) bearings which are assembled and sealed prior to installation. It is suitable for heavy unit loads and use under severe wear conditions, such as in crawler track chains and loader bucket pivotal pin joints. A brief history of U. S. manufactured track pin joints is included to show the progress in extending the service life of these devices.

Reliability is an important performance parameter often referred to subjectively in terms such as “high reliability” but seldom measured or verified. This results from one or both of the following reasons: ○ Measurement of reliability occurs over a long time span. Measuring reliability in the user environment can require months or years of operating history; whereas, acceleration, turning radius, and other performance parameters can be measured with a short term controlled experiment. Without immediate results, diligence in data monitoring often deteriorates until data value is questionable. ○ There is a false notion that complex statistical techniques are necessary to make useable estimates of reliability levels and patterns. A process is proposed in this paper whereby users, distributors, or manufacturers can quantitatively measure reliability in the user environment.

The accuracy demanded for the finished surface of leveling operations is becoming more severe each year. To cope with this demand, new type automatic blade control system (Laser type ABC system) for earthmoving machines have been developed. To realize the most suitable system for machines equipped with automatic controls, and most of components including sensors have developed in our engineering center. By adopting this system, the operater’s blade adjusting work has been signifficantly reduced. Operation can be performed at speeds up to 10 km/hr, and the accuracy of finished surface can be obtained within ± 2 cm.

Engineering plastics, which offer multiple high performance properties for heavy duty components are explained by molecular structure of high polymers. Technological behavior, which is unique to polymers, including friction, wear, fatigue resistance, contact pressure reduction, temperature and time dependency elucidate their functions as machine parts. Design criteria and fabrication characteristics of plastic parts are illustrated and exemplified as wear pads, seal rings, bearing bushings, sheaves, tubing, hydraulic hoses and functional coatings presently used in construction industries.

The processing, compositions, properties and strengthening mechanisms of the high-strength low-alloy plate grades are summarized. In the as-rolled condition these plate grades can have yield strengths to 80,000 psi. In a quenched and tempered condition both 100,000 psi yield strengths and abrasion resistant grades are available. New improvements in toughness, weldability and formability can be obtained primarily through steel desulfurization and sulfide shape control.

The purpose of this paper is to describe the advantages and validity of substituting the high-performance zinc casting alloys, ZA-12 and ZA-27, for bronze in selected low-speed, medium temperature bearing and bushing applications. Because the cost per unit volume of ZA-12 and ZA-27 is less than half that of SAB 660 bronze, these zinc alloys will provide major cost savings in the OEM and replacement markets whenever they equal or exceed bronze performance on the selected applications. For the foundry, these alloys offer significant advantages over bronze: lower energy requirements, no dependency on tin (a strategic material), and no pollution problems common to the leaded bearing bronzes. With a natural lubricity and hardnesses exceeding those of 660 bronze, the the properties of ZA-12 and ZA-27 alloys indicate good bearing potential.

An amazing number of both large and small companies do not have an adequate equipment maintenance management system. A conservative estimate indicates that at least 70% of American equipment-related businesses do not have adequate predictive maintenance programs. On a nationwide scale, a change is needed from a wasteful throw-away society to a maintenance conscious nation protecting our resources. To remain competitive, all companies need improved maintenance to achieve their production schedules and to protect their equipment investments. Substantial equipment operating cost savings can be realized through more efficient equipment management. These savings are available to all companies progressive enough to use computers to modernize their equipment management and maintenance operations.

Maintenance and repair costs are a major part of total operating costs on Off-highway equipment. Because of this, more emphasis must be placed in these areas during the design process. Reviewing the actual hardware and judging acceptability/unacceptability on the basis of current production counterparts or studies on competitive machines is not adequate. Ease of maintenance and repair must be considered in detail very early in the design process, preferably the feasibility phase, and reevaluated as the design matures thru to production and after. The following offers guidance as to how this can be done.

A simple and feasible approach to the measurement of oxides of nitrogen (NOx) from internal combustion engines is to collect engine exhaust in bags and subsequently analyze the samples with conventional laboratory equipment. The measurement technique that was developed for this purpose incorporates a portable apparatus for collecting bag samples and fuel specific NOx emission calculation methods outlined in the July 23, 1979, Federal Register, Stationary Internal Combustion Engines--Proposed Rules.

An SAE recommended practice lists recommended intervals from 10 to 5000 hours for use in establishing maintenance intervals for earthmoving and construction machinery. Except for some “lifetime” lubricated items, the user has had some difficulty in handling maintenance logistics so as to capitalize on the infrequent interval. The most frequent interval has generally set the common interval for all machines in a fleet, irrespective of make or vintage. Past experience, manufacturer and user dilemmas, future trends, and prospects for significant change are discussed.

Solenoid and proportional control valves are two major types of electrohydraulic control valves that have been widely used in industry. Experimental tests were conducted to study the effect of contaminant on these valves. Test results demonstrate that contaminant drastically changes the performance characteristics of electrohydraulic control valves and leads to a catastrophic failure.