Press Releases

STILL reports all quiet on the Haldex hydraulic front
04-01-2011

STILL, the Hamburg-based leader in intralogistics, reports that the new Haldex CALMA pump fitted on its forklift trucks has made their steering function almost inaudible, while the lift and side shift functions are also considerably quieter.
CALMA is essentially a development of the Haldex WQ series pump, which was designed ten years ago to meet the requirements of a new low-noise electric forklift introduced by STILL. The WQ was the first-generation quiet pump from Haldex to feature dual flank engagement to reduce pressure ripple resulting in lower noise.

In addition to the low noise design, Haldex integrated a pressure plate that provided additional low speed capability for STILL's unique method of operation. The plate allows the pump to be operated at full pressure and low speed, so enabling precise positioning control for various vehicle functions. This feature also provides the ability to maintain efficiency and durability under severe operating conditions.

The new CALMA is a second-generation development of the WQ series, designed to provide even quieter performance without sacrificing the wide speed range and durability of the original pump. CALMA has demonstrated significantly lower noise operation when compared with other external gear pumps as well as comparing favourably with more expensive internal gear pumps both on efficiency and low noise operation. Sound power testing in comparison with other quiet gear pumps showed CALMA achieved significant reductions in noise during the steer, tilt and lift functions by as much as 50% to 85%, which means significantly enhanced comfort for operators of STILL lift trucks.

The result of extensive research and development, CALMA features a newly engineered tooth geometry, innovative true dual-flank gear engagement, reduced trapped oil volume and advanced trapped oil management. The design reduces pressure pulsation by 75%, which is the key factor determining the pump's noise levels.

It also reduces energy consumption. Considerable excess hydraulic flow is generated in manoeuvring the vehicle and this energy would normally be dumped via valves, creating waste heat and a premature drain on battery power. CALMA's adjustable and low-speed capability avoids unnecessary power drain and further increases battery life.

The trend towards lower noise standards, which has been encouraged by recent legislation in Europe and elsewhere, also applies to other markets including truck, bus and off-highway, where CALMA is also expected to find many applications. The new pump is well suited to electric aerial work platforms and other mobile equipment where low noise, low speed and high efficiency are required.

Like other products in the Haldex range, the new CALMA pump is designed to be used as a single unit or as an element within multiple hydraulic assemblies. The modular philosophy common to the Haldex range means that standard housings can easily be varied to incorporate different functions and different internal connections. The modular approach also helps to ensure the very exacting production standards required to deliver market-leading technologies cost-efficiently.

STILL, a member of the KION Group, is a leading supplier for the intelligent control of intralogistics. The company offers fork lifts, tractors, warehouse and platform trucks, plus the latest warehouse handling equipment and forward-looking services as well as a tight service network, software solutions, financial services and further system solutions.

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