By Richard T. Schneider
Designed for simplicity and high but quiet performance, Eaton’s Model ADY098 Series 620 open-circuit piston pumps for mobile equipment applications are only 11.4-in. long, weigh 91 lb, yet transmit 134 hp. The small size makes them well suited to fit into the tighter confines of Tier IV engine compartments. The introductory pump has a maximum displacement of 98 cc/rev, with subsequent models to be sized at 65, 74, and 120 cc/rev.
A tight swashplate angle of 15° contributes to the short overall envelope and improve speed response to the control. Lubrication channels in the swashplate bearing reduce friction and also increase responsiveness. A bi-metal valve plate reduces noise generation. The pump’s two-piece housing reduces leakage potential, while its interior ribs limit vibration and noise.
A check valve between the case and the inlet reduces pressure spikes. The pump’s control piston has a low-friction coating that increases responsiveness. High-load bearings and a stiff shaft extend the pump’s operating life to 13,600 hr at rated conditions.
Options include: load sensing, pressure compensation, cold-start valve, external manual stroke adjuster, and a variety of mounting and input shaft configurations.