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xxx 2011-03-22

Re-shaping counterbalance technology

Re-shaping counterbalance technology

Increased stability while maintaining a high pilot ratio is possible with the unique poppet geometry of Rexroth’s new VBSO-P family of counterbalance valves.

Rexroth’s VBSO-P series counterbalance valves are changing the shape of load-holding technology with a newly developed poppet profile. By subtly altering the geometry of the load-holding poppet, VBSO-P valves provide stable load lowering while minimizing the energy necessary to pilot open the counterbalance valve.

Manufacturers of lifting equipment are too often forced into a difficult compromise to achieve good performance when lowering a boom structure. All types of cranes, telehandlers, or aerial work platforms can experience instability, or “chatter,” at various points in their lowering operations. To counteract this problem, designers must frequently choose to reduce pilot ratios or throttle pilot signals resulting in increased pressure to open the valve or potentially hazardous delays in opening or closing the device.

A new solution to instability is found among Rexroth’s wide range of load-holding solutions. Series VBSO-P counterbalance valves employ a newly designed load-holding element that provides a non-linear flow gain to combat the conditions, which trigger instability. Instead of increasing the resistance to opening like low-ratio counterbalance solutions, the opening characteristic of the valve is regulated through the shape of the poppet. Low ratios and high resistance equate to higher pump pressures and therefore more energy consumption during the lowering process. By preserving the ability to use higher pilot ratios, VBSO-P series valves ensure optimized energy consumption and smooth lowering in tandem.

Through advance machining techniques developed over 40 years of load-holding valve manufacturing, Rexroth has refined the ability to control the shape and flow gain characteristic of counterbalance valve control elements. Machine-specific, customized solutions, as well as application to its line of cartridge valves, are available with this new technology – literally reshaping mobile equipment load-holding performance.

Bosch Rexroth AG is one of the world’s leading specialists in the field of drive and control technologies. Under the brand name of Rexroth, the company supplies more than 500,000 customers with tailored solutions for driving, controlling and moving. Bosch Rexroth is a partner for industrial applications and factory automation, mobile applications and renewable energy.

As The Drive & Control Company, Bosch Rexroth develops, produces, and sells components and systems in more than 80 countries. In 2009 Bosch Rexroth, part of the Bosch Group, achieved sales of around $5.7 billion (4.1 billion Euro) with 34,200 employees. For more information, please visit:


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