Haldex Launches Noise-Reducing Gear Pump

Haldex Hydraulics Systems, Rockford, Ill., has launched a gear pump that reduces noise by up to 10 dB or 85 percent in low-speed applications. The product, named the Calma pump, is particularly advantageous for electric vehicles, such as forklift and warehouse trucks.

The Calma features a newly engineered tooth geometry, true dual-flank gear engagement, reduced trapped oil volume and advanced trapped oil management. According to product literature, the design reduces pressure pulsation by 75 percent, the key factor in determining the pump's noise levels, while also reducing energy consumption.

In the market for electric and gas-powered vehicles, low noise is a key requirement, while low-speed operation enables improved control and positioning for various vehicle functions. Consequently, gear pumps that can operate efficiently and quietly at low speeds are now among the most important priorities for electric vehicle designers. The trend toward lower noise standards, which has been further encouraged by 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.

Apart from its low noise benefits, the Calma pump offers important energy-saving advantages. Considerable excess hydraulic flow is generated in maneuvering the vehicle and this energy is normally dumped via valves, creating waste heat and a premature drain on battery power. Calma's adjustable and low-speed capability avoid unnecessary power drain and further increase battery life.

Calma is especially well suited to applications on electric counterbalanced lift trucks and warehouse lift trucks. Calma is also well suited to electric aerial work platforms and other mobile equipment where low noise, low speed and high efficiency are required.

Following an exhaustive program of research and development in collaboration with the University of Dresden, Haldex Hydraulics has introduced a range of Calma pumps in displacements from 6.2 cc to 23.7 cc. A decade ago, the company launched the first WQ series (quiet) gear pump product line, which introduced the concept of true dual flank engagement of the gear teeth (as opposed to “almost dual flank engagement”). This technology is unique to Haldex and is intended to reduce the amplitude of the pressure pulsations introduced into the hydraulic system.

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 technologies cost-efficiently.