Press Releases

New Low noise hydraulic pump
18-09-2009

Haldex Hydraulics Systems has launched the Calma mobile hydraulic gear pump, which is designed to reduce noise by up to 10 dB(A) or 85% in low-speed applications particularly in forklift
and warehouse trucks, as well as a range of on-and off-highway equipment.

Testing of the Calma pumps, Haldex said both static and in-vehicle tests demonstrated significantly lower noise operation. As such, the company said Calma is especially well suited to applications on electric counterbalanced lift trucks and warehouse lift trucks.

Sound power testing on these types of vehicles showed Calma provided significant reductions in noise as much as 50 to 85% during steer, tilt and lift functions, Haldex said. Calma technology is also seen as applicable to electric aerial work platforms and other mobile equipment uses where low noise, low speed and high efficiency are required, Haldex said.

The Calma pumps were developed in collaboration with the University of Dresden, Germany. Haldex first ventured into low-noise gear products a decade ago when it introduced the first WQ series (quiet) gear pump product line.The WQ pumps introduced Haldex's concept of true dual-flank engagement of the gear teeth, which reduces the amplitude of the pressure pulsations introduced into the hydraulic system.
The new Calma pump is designed for use 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 be varied to incorporate different functions and different internal connections.

Haldex Hydraulics Systems has launched a new mobile hydraulic gear pump, called Calma, that the company said is designed to reduce noise by up to 10 dB(A) or 85% in low-speed applications such as electric vehicles including forklift and warehouse trucks, as well as on- and off-highway uses. The pumps will be manufactured both at Haldex's Rockford, Illinois, U.S.A., operations, and its Hof, Germany, facility.

The Calma (WQII) pumps have displacements from 6 to 32 cc and feature a newly engineered tooth geometry, true dual-flank gear engagement, reduced trapped oil volume and advanced trapped oil management.Haldex said this reduces pressure pulsation by 75%, a key factor in determining the pump's noise levels, while also reducing energy consumption.
Haldex said that 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. As a result, pumps that can operate efficiently and quietly at low speeds are gaining interest from vehicle designers in these markets. Further, the trend toward lower noise standards, which has been encouraged by legislation in Europe and elsewhere, also applies to other markets including truck, bus and off-highway, where Haldex said Calma is also expected to find applications.
Apart from its low-noise benefits, Haldex said the Calma pump also has energy-saving advantages. Excess hydraulic flow is generated in maneuvering a vehicle, and this energy is often dumped via valves, creating heat and - in electric vehicles - a premature drain on battery power. Calma's adjustable and low-speed capability avoids unnecessary power drain and increases battery life, Haldex said.

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