Eaton’s 420 Series Piston Pumps with Hydro-mechanical Torque Control

Diversified industrial manufacturer Eaton Corporation has added a hydro-mechanical torque control option and several performance upgrades to its 420 open circuit piston pump product line. The 420 pump with hydro-mechanical torque control automatically senses heavy loads and adjusts hydraulic fluid flow accordingly.  

Photo by Eaton Corporation

It is intended for moderate-flow, high-pressure mobile applications such as compact wheel loaders, telehandlers, rough terrain forklifts, telescopic booms, sweepers, backhoe loaders, and garbage trucks. To accommodate the new torque control, the pump housing was designed to decrease airborne noise to 76 dBA at 1,800 rpm and 207 bar. A case-to-inlet check valve \ was added to improve cold weather operation and provide added protection to the seals and rotating group. The new torque control works in parallel with the standard compensator, using a special mechanism to replace the control piston.

“In compact and mid-size equipment, torque almost always needs to be controlled,” said Eaton Product Manager Todd McIntyre. “Limiting the torque at the pump shaft across a wide range of engine speeds provides operators with the benefits of increased productivity, greater efficiency and fewer engine stalls. The result is lower engine emissions and improved fuel economy.

 “Productivity is enhanced by increasing the speed with which the vehicle function is performed due to flow rate changes made by the torque control system. For example, raising a heavy load with a set of forks on a telehandler places a significant amount of pressure on the hydraulic pump and system. To prevent engine stalls without limiting the telehandler’s lifting capacity, manufacturers not using torque control would be forced to use a smaller displacement pump that significantly slows the operation of the forks. Torque control automatically senses heavy loads and adjusts flow accordingly. Limiting the flow in high pressure situations limits the torque the pump can apply to the engine and, as a result, avoids the corner horsepower point and prevents the engine from stalling. It also allows for higher flow and quicker operation when the set of forks is empty, which means higher productivity.”

Eaton’s 420 pumps offer outstanding power density that is not compromised by the use of torque control.