Mechanical Technology April 2015

⎪ Hydraulic and pneumatic systems ⎪

Hydraulic pump and motor

Prior to his visit to Brevini Fluid Power in Italy, MechTech talks to Axiom Hydraulics’ Neill Simpson (left) about the company’s use of SAM Hydraulics’ pumps and motors in custom-designed solutions for the local market.

A t the time of writing, Axiom’s Eugene Tondolo, current presi- dent of the South African Fluid Power Association (SAFPA) and Neil Simpson, the company’s MD, were about to set off for Italy on a one-week visit to the Brevini Group, the OEM for the SAM Hydraulik product range. Founded in the 60s by the Brevini brothers in Reggio Emilia in Northern Italy, Brevini is now a multinational corporation that owns Brevini Power Transmission, Brevini Fluid Power and Brevini Gear Systems. The Fluid Power business, alone, directly employs 2 500 people in 13 establish- ments spread across Italy, Germany, China and the USA. The SAM Hydraulik brand was estab- lished in Reggio Emilia in 1974 as a spe- cialist in the hydraulic transmission sec- tor. The SAM product line is spearheaded by its fixed and variable displacement medium and high pressure axial piston pumps and motors, for both closed- and open-loop circuit applications, along with its range of low speed high torque orbital motors of the Gerotor type. “But Brevini Fluid Power also pro- duces a wide range of proportional directional control valves for mobile applications such as: cranes; concrete pumps; drilling machines; shipbuilding

and forestry machinery. We will also be spending some time learning about its new products, a slow speed hydraulic motor, which is locally distributed by one of our sister companies, Hydraulic Tools in Cape Town, and a new hydro- static steering system,” Simpson tells MechTech . “The new low speed motor is doing rather well,” Simpson continues, “so we would like to learn more about it.” Axiom Hydraulics used to market the original HPI Nichols Gerotor for low speed ap- plications, before the global take over of that company by Parker. “We currently don’t really have an equivalent in our range at Axiom, but we are happy to continue to source the Brevini equivalent through Hydraulic Tools, which also has a distributor up in Johannesburg called Delflow,” he says. “In South Africa, these are widely used on agricultural vehicles carrying granulated animal feed, for example. Several low speed orbital motors are used in series to drive the screw conveyors to discharge exact amounts of feedstock,” Simpson explains. “You might also have seen a maize harvester taking the tips off the cobs. Usually, travelling next to the harvester is a truck that is loaded directly from the moving harvester. Low speed SAM Hydraulik motors are ideal

A Peake Mk3a dual-tank crop sprayer manu- factured by Peake Equipment near Brits in South Africa. As well as incorporating hydro- static steering for two- and four-wheeled steering, these machines use Black Bruin hydraulic wheel motors to deliver torque to all four wheels. A diesel engine drives the SAM Hydraulik pump to power the hydraulic circuits and SUN Hydraulics cartridge valves in a manifold block supplied by Axiom Hydraulics are used for control. vehicles, these steering unit sit under- neath the vehicle’s steering wheel. As the wheel is turned, this unit pumps exact quantities of oil to the hydraulic cylinders connected to the wheels. “This is a very practical and common way of steering off road vehicles for agriculture and construction. We use this system on off- road agricultural vehicles with four-wheel steering. When travelling on roads, these vehicles only require two-wheel steering, so using hydraulics offers a simple way of switching between four-wheel and two-wheel steering systems. “SAM’s hydrostatic steering units are servo units, meaning an error-correction signal is used to control the exact me- chanical positions of the steering cyl- inders. A small mechanical input from the steering wheel is translated into a powerful proportional output steering position. And the drive and the feedback are all hydraulic. A defined quantity of oil in the cylinder governs the exact position of the wheels,” Simpson explains.

for use in driving the screw con- veyor loading these trucks,” he adds. Brevini also makes hy- drostatic steering systems, “which we may be interested in”. Widely used on off-road SAM Hydraulik S6CV series variable displacement, axial piston pumps have a swash plate design and are ideal for closed circuit hydro- static power transmission and high-pressure applica- tions. S6CV series pumps are available for flows up to 128 cm 3 /rev and with several

control options.

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Mechanical Technology — April 2015