Komatsu America introduced the D39EX-22 and D39PX-22 crawler dozers during ConExpo 2008. Designed for work in general construction, site preparation, home building, forestry, and utility applications, the new machines feature a hydrostatic transmission (HST) and a new cab-forward design that improves operator visibility, machine balance, ride, and stability.
Powered by a 4.5-L, U.S. EPA Tier-3-emissions-certified Komatsu SAA4D107E-1 engine, the new models push with a net horsepower of 105 hp (78.3 kW) at 2400 rpm. Ranging in operating weight from 10.42 to 10.90 ton (9.45 to 9.89 t), depending on the machine version, both dozers are available in standard (EX) and low ground pressure (PX) models that allow customers to match weight distribution and flotation options to their application.
Both models are equipped with Komatsu’s own hydrostatic transmission, comprising dual-path closed circuits with two variable-displacement piston pumps and two variable-displacement travel motors. With the push of a button, the operator can select between variable speed, which allows adjustable travel speed through 20 incremental speeds, or quick-shift speed selection, which enables the operator to select three predetermined speed settings to match job conditions. The system also includes dynamic hydrostatic braking, which operates until the machine stops moving, after which the parking brake engages; this feature helps to minimize brake wear.
Steering clutches and brakes have been eliminated by the D39-22 dozers’ hydrostatic steering system, which facilitates smooth, powerful turns and agile movement when dozing, even in gradual turns. A large power angle tilt blade with a capacity of 2.89 to 3.01 yd3 (2.21 to 2.30 m3) helps to keep more material on the blade for higher productivity.
Designed for durability, the D39-22’s heavy-duty undercarriage features large links, large bushing diameters, and wide sprocket teeth. The one-piece track frame is welded to the main frame with large connecting bars and weldments. Track life is enhanced by increased bushing diameter, improved seals, a longer link pitch, and a lubricated track.
The latest Komtrax technology, provided standard with the new dozers, sends machine operating information to a secure website via wireless technology. Hour meter, location, cautions, maintenance alerts, and more are relayed to the web application for analysis. The Komtrax fleet-monitoring system helps to increase machine availability, reduce the risk of machine theft, facilitate remote diagnosis, and provide other information to help optimize business efficiency and productivity.
Blade visibility has been improved with a new and larger cab-forward design with integrated rollover and fall-over protective structure, large glass windows, and more room for the operator. Internal cab air pressure and air filters help to minimize dust entering the cab, and new cab damper mounts suppress noise and vibration when traveling over rough terrain.
Komatsu’s low-effort Palm Command Control System with travel joystick is ergonomically designed for efficient operation and enhanced operator comfort. A blade control joystick utilizes the proportional pressure control valve for fine control of machine operation.
Daily engine checks are grouped at the left-hand side of the engine compartment for easy access, and the rear-mounted swing-up electronically-controlled reversible hydraulic fan allows for easy checking of the radiator, oil cooler, and charge air cooler. The new dozers feature large links and large-diameter bushings for longer undercarriage life, and the intervals between engine and hydraulic oil changes have been extended compared to previous models.