Hydraulic servopress works without valves

Valveless hydraulic drive converts standard press into servopress.

Edited by Alan L. Hitchcox

Compact PSH hydraulic press
Compact PSH hydraulic press
Compact PSH hydraulic press drive from Voith Turbo H+L Hydraulic is powered by an electric servomotor driving a fixed displacement hydraulic pump to control flow and pressure based on demand. Benefits include higher energy efficiency and quieter operation than conventional drive systems controlled by valves.

A hydraulic drive without conventional control valves? That’s how the PSH press drive is described by officials at Voith Turbo H+L Hydraulic, Rutesheim, Germany. Instead of using conventional servo or proportional valves to control flow and pressure in a hydraulic press drive, the PSH drive controls the rotational speed and torque of an electric servomotor that drives a hydraulic pump. Providing closed-loop control of motor speed and torque, in turn, controls flow rate and pressure of the press’s hydraulic system.

Officials say that not only can the drive transform any press (even fixed speed) into a servo press, but it can also save up to 50% in electricity costs. An intelligent control system allows flexible application of the press. The drive can produce maximum speed when load is light, then automatically accommodate greater pressure as load increases. The result is increased productivity of the press and higher quality of the finished parts. The drive is well suited to presses because it controls a single axis.

Doing away with convention
In the PSH hydraulic press drive, conventional valve and control technology is replaced by a servo pump. The servo pump delivers a variable volume flow, has high dynamic response, and low noise generation. This concept allows optimizing of power and speed to the pressing process. It also simplifies the design of the press drive without impairing functionality and performance.

The PSH can be incorporated into the press and is suitable for both new systems and retrofits. Other advantages are low costs for commissioning, training, and maintenance. Electronic sensors monitor key parameters to ensure high diagnostic functionality and allow preventive maintenance. Press operators benefit from this by high uptime and improved operating safety.

For more information, call +49 7321 37-2802 or visit www.voithturbo.com.