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Komatsu's bulldozer D65 has undergone a full-scale model change for the first time in 22 years into a new model D65-12. This new model bulldozer has been developed to comply with the company's desired design philosophy “Friendly to People, Kind to People”. A “Revolutionary” advancement was achieved in comparison with the conventional ones which were developed and improved by producers' focus on productivity and economical efficiency. This model change not only has allowed production of a new-age bulldozer equipped with “Strength” and “Friendly to People”, but also has created a new turning point in Komatsu's bulldozer development. To realize this new bulldozer development, a number of new technologies and patents have been devised and put to practical use. This paper presents Komatsu's design philosophy and major new bulldozer technologies put to practical use.

Of all the parts used on crawler-type construction equipment, the track bushings in the undercarriage of large bulldozers are subjected to particularly severe load conditions. A new and innovative heat treatment technology has been developed in order to improve the durability of these bushings from the point of their wear and fatigue crack characteristics. A new steel material has also been specified to match this heat treatment technology. The bushings thus developed have been extensively tested on bulldozers in customer service and proved to be successfully applied for production. They also offer a possibility for considerable reduction in manufacturing cost.

KOMATSU has successfully developed and marketed the HYPER GX series computer-controlled, intelligent hydraulic excavators. The development concepts of the HYPER GX series are as follows: 1. To improve safety at construction sites by use of measuring functions which reduce the number of ancillary workers. 2. To improve working environment and the quality of work by use of automatic functions which reduce operator fatigue and time required to complete a job. 3. To solve the problem of shortage of experienced workers by the use of operator support functions which allow easy operation even for inexperienced or older operators. Representative of these is the fully automatic grading function, with which the movement of boom, arm and bucket is computer-controlled to enable automatic excavation at a predetermined gradient.

After new transmission lubricants are developed there is an extensive validation program where friction durability testing is performed on multiple clutch materials. Each durability test can run for long terms and the entire validation program can take much longer terms. A well designed lubricant and friction material will deliver the necessary friction control for construction equipment to operate at optimum level. A mechanistic construct has been evaluated to calculate friction durability in clutch systems based on fluid and surface tribological properties. Fluid properties include both boundary frictional and rheological effects. Surface properties include elastic modulus, surface roughness, asperity density and asperity tip radius. Using this mechanistic construct friction durability has been predicted.