Compact design and energy-efficient operation
The MPR 50 medium-pressure axial-piston pump from Linde Hydraulics represents a new drive concept for the work functions of mobile machines equipped with an electronically controlled propel drive. When compared directly with internal-gear pumps and load-sensing pumps with pressure cut-off, it is clear that this type of pump offers significant advantages. It is more compact, it can be easily integrated into the existing propel drive control and it helps to save energy.
When compared with other drive systems for use in working hydraulics (i.e gear-pump configurations and load-sensing pumps with pressure cut-off), the new medium-pressure pump offers a significantly more compact design. For example, when used in a wheel loader, an MPR 50 is approximately 70 mm shorter than a standard gear pump configuration. In addition, by using the MPR 50 you can reduce the energy consumption of the working machine.
Integrating the pump into the electronic vehicle management system is a straightforward process. The swash angle is proportional to the input current. The control device with position feedback control corresponds to the equivalent mode used on Linde HPV-02 pumps and ensures that the flow is adjusted to the precise value that is currently required.
The electronic control system enables engine map optimisation of the diesel engine, thereby ensuring that it is always operated in the optimum range. As the MPR 50 is directly controllable, the same volume flow - and therefore the same actuator speed – can be generated at a lower diesel engine speed. This lowers fuel consumption and pollutant emissions whilst reducing the noise level of the machine.
Compact, easy to control, designed for high-performance and energy-efficiency: These are the key characteristics of the new MPR 50 medium-pressure pump.
The new medium-pressure pump also offers significant advantages over load-sensing pumps with pressure cut-off. The new pump uses significantly less energy during cold starts because it has a flow of 0 ccm/rev in the neutral position and does not need to be swashed back with system pressure. In many cases, this means the starter-motor output can be reduced.
In addition to increased efficiency, the machine operator also benefits from highly dynamic work function responses, and therefore from increased productivity — in line with the LinDrive® philosophy. The pump is controlled by the input signal and responds directly to the driver's commands and therefore to the electronic control system. This direct and precise signal conversion is a fundamental prerequisite for electrical demand control. Thanks to the optimised SPU silencer, the MPR 50 generates low-pulsation pressure and flow, thereby minimising the development of structure-borne noise and vibrations. In addition to dynamic drive behaviour, this innovation results in a high level of driver comfort.
A further advantage of the new pump is that you can opt to equip it with an integrated fan feed pump, which means it can assume the role of feeding and supplying the fan drive. Thanks to the standardised interface and flange-mount priority valve, it is easy to implement supply of a load-sensing steering function using the MPR 50, and a high level of safety and steering comfort is also assured. This option reduces weight when compared with the multiple gear-pump configurations conventionally used; it reduces the complexity of the drive and thereby the time spent on installation, and it enables an even more compact design.
Practically unbeatable in terms of compactness: The Linde MPR 50 with integrated
16-ccm/rev gear pump compared with conventional load sensing pumps featuring 46 ccm/rev and 45 ccm/rev with an integrated 16-ccm/rev internal-gear pump.
The new medium-pressure pump features a high suction speed of up to 3000 rpm and is used within an open circuit. When developing the pump, Linde Hydraulics was able to draw on the tried-and-tested basic designs of the high-pressure pump series 02, intended for use in both open and closed circuits.
The specialist in hydraulic and electric drives for mobile machines has designed this new pump with the aim of equipping powerful, highly productive machines such as telehandlers, tractors and pavers. In addition to performance and energy efficiency, these target machines demand drive components that are as compact as possible.
During the initial practical tests, some machines were equipped with the MPR 50. The machine users reported positive experiences in all areas: The fork lift trucks and wheel loaders operated at significantly lower noise levels and used up to 20% less diesel fuel when equipped with the new pump. In view of the advantages offered by the new pump, Linde Hydraulics believes that there is a large market for the new drive concept and will design a versatile medium-pressure range going forward; this will include development of additional nominal sizes and expansion of the alliance portfolio of Eaton pumps.