Image

Hydraulic Die-Cushion Drive Can Save Significant Energy on Presses

Oct. 10, 2014
Voith’s CSH die-cushion drive, which consists of a servopump and a double-acting die cushion mounted underneath the bolster plate. needs no valves and significantly reduces energy consumption of the press.

Some modern industrial hydraulic systems use closed-loop, variable-speed motors to drive fixed-displacement pumps, instead of using fixed-speed motors to drive variable-displacement pumps. Simple systems just use the motor to vary the flow from the pump in response to load demands. As with conventional HPUs, this setup could provide hydraulic power to several circuits. The higher-end systems use a pump driven by a bidirectional servomotor. The combination is called a servopump. The powerful motors have such quick response that they can drive a cylinder or motor directly — without having to go through a directional or servovalve. When the system idles, the drive becomes a torque motor, producing just enough flow to compensate for case drainage. Flow, direction, and pressure are monitored and controlled throughout machine cycles.

The high volumetric efficiency of the servopump contributes to very accurate control of the drive.

An application of this modern concept is Voith’s CSH die-cushion drive, which consists of a servopump and a double-acting die cushion mounted underneath the bolster plate. Lying at the heart of the drive is the servopump’s internal-gear pump that has high volumetric efficiency, permitting highly accurate control. This innovative drive for demanding forming processes needs no valves and reduces energy consumption of the press significantly.  

Download this article in .PDF format
This file type includes high resolution graphics and schematics when applicable.

With conventional die-cushion drives that combine both a die cushion and pressure-relief valve, the die cushion’s work will become irretrievably lost. In relatively stark contrast, the Voith CSH system feeds the mechanical power of the servopump back to the process, through the motor, in the form of electric power.

The CSH hydraulic die-cushion drive reduces energy consumption to make high overall-efficiency levels achievable.

This ultimately reduces energy consumption and can reach overall energy-efficiency levels that were previously unattainable. In addition, the servo-hybrid CSH die-cushion drive utilizes a smaller oil reservoir and less oil, and it doesn’t require any cooling.
Furthermore, the CSH is freely programmable in terms of speed, force and position control, and acceleration — making the drive particularly applicable to forming processes involving complex geometries. The accelerated die cushion adjusts to the position-time curve of the ram and, in contrast to a single-acting die cushion, reduces tool impact on the workpiece. This helps improve surface quality, protects both the machine and tool, and prevents damage such as cracks and creases on the workpieces.

Voith Turbo GmbH is located in Crailsheim, Germany.

Continue Reading

Handbook Simplifies Advanced Aspects of Mobile Hydraulic Controls

May 10, 2017
Author Brendan Casey lays out his hydraulics know-how that he acquired over 27 years in a simple handbook made for people that want to improve their skills in troubleshooting ...

Kidney loops: They aren't just for hydraulics any more

Sept. 1, 2004
When was the last time you changed the oil in your refrigerator's compressor? That was a question posed to me by Ken Stofen of Racine, Wis. The answer, of course, is never, and...

Sponsored Recommendations

MONITORING RELAYS — TYPES AND APPLICATIONS

May 15, 2024
Production equipment is expensive and needs to be protected against input abnormalities such as voltage, current, frequency, and phase to stay online and in operation for the ...

All-In-One DC-UPS Power Solutions

March 13, 2024
Introducing the All-In-One DC-UPS, a versatile solution combining multiple functionalities in a single device. Serving as a power supply, battery charger, battery care module,...

Motor Disconnect Switches

March 13, 2024
With experienced Product Engineers and Customer Service personnel, Altech provides solutions to your most pressing application challenges. All with one thought in mind - to ensure...

DC Power Solutions: Streamlined Power Supplies for Every Need

March 13, 2024
CBI All In One UPS Power Solutions combine the requirements for several applications in just one device which can be used as power supply unit, battery charger, battery care module...