Gear pumps give mobile applications the silent treatment

Agricultural machinery company, Weidemann, offers a solution in the form of its new 1160 eHoftrac. The 1160 eHoftrac is fitted with Bosch Rexroth’s new generation of external gear pumps, SILENCE PLUS, which reduce noise level for work hydraulics, so that mobile machines with electrical drives can function as quietly as possible.

One of the first businesses to trial the 1160 eHoftrac in day-to-day business was a well-known zoo in Copenhagen. Animal enclosures are just one example where quiet and exhaust-free machines can be utilised effectively.

The 1160 eHoftrac yard loader has two electric motors – one serves as the travel drive, while the second drives the SILENCE PLUS external gear pump. This improves energy efficiency of the vehicle, which is reflected in more operating time per loading cycle.

The travel drive only requires electricity when the yard loader is being driven. The same applies to the hydraulic pump, which is powered by the electric motor when hydraulic pressure is required. The variable motor speed control ensures both motors are always operating with the appropriate RPM, which helps minimise energy consumption.

On average, the battery lasts for two to five hours, dependent on operating conditions and energy turnover. Additional savings in operating costs can be made in future when buildings have photo-voltaic systems installed.

A beneficial aspect, particularly for the agricultural market, is that it can be used during any time of day. The machine’s quiet and exhaust-free operation mean employees no longer need to restrict themselves to narrow time windows in the morning and evening. Consequently, work can be spread out throughout the day without causing disturbance.

The combination of electric drives and quiet, independently driven hydraulics increase productivity, while drivers benefit from improved perception and quicker reaction times.

The SILENCE PLUS external gear pump, works quietly and also generates a frequency similar to that of an electric motor, and the hydraulic pump blends in with the quiet operating sounds of the travel drive.

Traditionally, external gear pumps have been robust units for pressure of up to 280bar. With a number of structural improvements, Bosch Rexroth was able to reduce the noise emissions by up to 15dbA when compared to conventional pumps. One reason for the quiet operation is the angular tooth profile which prevents compressed oil entrapment and subsequently eliminates vibrations.

With regards to sustainability, the electric drive’s batteries can be charged using electrical power generated on-site with photo-voltaic systems, biomass or wind. Not only does this contribute to a more sustainable climate but, this technology also has positive effects on the health of both employees and animals.