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Hydraulic fluid (HF) specifications for mobile construction equipment called JCMAS HK and HKB have been established by the Fuels and Lubricants Committee of Japan Construction Mechanization Association (JCMA). The specifications are designated by two viscosity categories of single grade and multigrade. Each category has ISO viscosity grade (VG) 32 and 46. The JCMAS HK oils are recommended for use in hydraulic systems designed at pressure up to 34.3MPa(5000psi) and to heat hydraulic fluid up to 100 °C. These oils also provide wear control, friction performance, oxidation and rust protection, seal swell control and filterability performance. Two piston pump test procedures were developed to evaluate lubricating performance of these oils under high pressure conditions. The JACMAS HKB oils are classified as environmentally friendly oils due to the additional requirement for biodegradability.

We have found that most commercially available biodegradable hydraulic oils show low static friction coefficients not depending on the kinds of wet friction materials. Since hydraulic motors of a hydraulic excavator contain wet parking brakes, the most commercially available biodegradable hydraulic oils can not provide enough brake torque capacity to park safely. Furthermore, all kinds of commercially available biodegradable hydraulic oils do not have adequate oil performance for a hydraulic system of construction eq ipment. Thus we have developed a n high performance biodegradable hydraulic oil. To obtain a high static friction coefficient and compatibility with elastomers, a new synthetic ester base fluid has been developed. To improve oxidation stability and to attain compatibility with mineral oil based hydraulic oils,. an additive formulation has also been developed.

Since construction machinery manufacturers recommend various brands and types of greases for their machinery, customers would benefit from a standardized grease which can be used in all construction machinery. Furthermore, construction machinery manufacturers have many experiences of field problems caused by commercially available and commonly used EP Lithium greases. Therefore, the Fuels and Lubricants Committee of Japan Construction Mechanization Association (JCMA) has developed a new grease specification called “Japan Construction Mechanization Association Specification (JCMAS) GK,” for construction equipment. The JCMAS GK includes requirements for National Lubrication and Grease Institute (NLGI) No. 1 and No. 2 consistency grades. The JCMAS GK greases have enough lubricating properties for periodical grease fitting of most construction machines, hydraulic excavators, bulldozers and wheel loaders. The JCMAS GK greases are applicable from -20 to +130 degrees Celsius.

In order to extend the oil drain interval and to prolong the engine service life, we have investigated the effects of engine load and wear on heavy-duty diesel engine oil deterioration and oil filter plugging. Furthermore, effects of oil quality on oil deterioration has also been studied. We have found in this study that the increase of blow-by gas flow due to excessive wear of engine components causes severe nitro-oxidation in heavy-duty diesel engines at a high engine load conditions similar to that observed in gasoline engines. The nitro-oxidation of engine oil also causes filter plugging. From the oils tested, the high ash oil showed better anti-nitro-oxidation performance than those with low ash.

Torqflow transmission, which is composed of planetary gear mechanism, multiple disk clutches and a hydraulic control unit, has been adapted for Construction Machine because it allows an easy selection of speeds (forward or reverse). Recently a rubber facing material with high coefficient friction has been used disk clutch's facing parts for compact design. Meanwhile, it's heat conduction is inferior to metalic disk to be usually used, so at engage time temperature of rubber facing disk is higher than metalic and it's ablasive wear ratio, which is verified to have influence on facing temperature by experiments, is increased far more than before. Therefore prediction of facing temperature has been more important than before. Now, in this report, study on transient thermal analysis is introduced because it's accuracy has come to practical level.

Recently, rubber tracked construction machines, particularly mini-hydraulic excavators, are successfully used for urban construction in Japan, because that have the following features. 1) They cause little damage to road surfaces. 2) Reduced vibration for operators and operating environment. 3) Low noise This paper outlines the development of the rubber track for small size bulldozers (4000 kg, 7000 kg ). The track composition is explained, computer simulations of the development and the performance of the tracks for bulldozers are explained.

To prevent engine scuffing in the field a new laboratory test called the Hot Tube Test has been established in order to evaluate the high temperature stability of diesel engine oils. In a strip mining application field test using 47 bulldozers powered by the same engine type, half of the engines suffered from piston scuffing failures when operated on a variety of commercially available API CD quality SAE 30 Grade engine oils. All the field test oils have been investigated using the Hot Tube Test, and an analysis of the results indicates that it would be possible to accurately predict scuffing failures by this test method. Furthermore, the reliability of this analysis has been verified by bench engine testing on reference oils. The reasons why the Hot Tube Test predicts the anti-scuffing performance of engine oils are discussed.