Sampierana moves ahead with Rexroth eOC: electronically controlled working hydraulics for compact equipment

Compact off-highway machines should be as maneuverable, versatile and energy-efficient as possible. A decisive key to this lies in the electronification of the working hydraulics. The fact that improvements in this respect can be combined with sustainable standardization effects is demonstrated by the new mini-excavators, wheel loaders and track loaders from the Eurocomach brand, which has been part of the Italian Sampierana Group for almost 30 years.

Sampierana found a way out of the previous design corset with the eOC electronic open circuit architecture from Bosch Rexroth. Its central component is an electrohydraulic axial piston pump operating in an open circuit with a swivel angle sensor and pressure sensors. The eOC pump is electronically controlled in a closed loop so that the required setpoints for torque, pressure or volume flow can be controlled independently of each other precisely and highly dynamically in the range of milliseconds. Using the associated BODAS eOC software, parameters such as dynamics and power control can be individually set, changed and combined during operation. The control software communicates via the CAN bus and can be installed either on a BODAS eOC controller from Bosch Rexroth or on a controller from a third-party manufacturer.

In a first project, Sampierana used the eOC architecture to develop the 60ZT and 65 TR mini excavators. While the 60 ZT has a zero radius profile with a monolithic boom, the 65T is equipped with a triple boom, which is particularly suitable for digging, handling and loading operations thanks to its small radius. Both models feature high performance and versatility thanks to eOC. While the low-noise axial piston variable displacement pump type A10VO realizes precise performance control, the compact RS12/EH control block ensures flow sharing (LUDV) and, with low pressure losses, in turn contributes to equally high-performance and energy-efficient working hydraulics.

Together with the open and scalable BODAS eOC pump control RC5-6/40 and the BODAS eOC software, the dynamic behavior and productivity of the machine can be specifically optimized, with the operator interacting directly with the machine's electronics via joystick and onboard display. Thanks to the situation-dependent modification of functional parameters such as delta-P, pressure gradient or volume flow, the mini excavators can choose to work slowly and precisely on the construction site or move larger quantities of earth at a rapid pace.

With the help of the eOC BODAS pump control, Sampierana has managed to increase the range of working modes and tools while increasing machine performance. "The working hydraulics can be precisely controlled with short response times," reports Giuseppe Fabbri. "At the same time, we can configure the system parameters very easily. We secure these advantages in the long term because the eOC BODAS system is designed to be open and scalable."

Sampierana can also point to improvements in terms of sustainability. On the one hand, less control oil is required because several hydromechanical controller axes for pressure, flow rate and torque have been combined into one. On the other hand, the dynamic adjustment of the control parameters minimizes the energy consumption of the entire hydraulic system. "On this basis, we can comply more easily with current regulations regarding ecomobility, emissions and efficiency and support our customers even better in meeting their climate protection targets," explains Giuseppe Fabbri. "This is an important competitive factor."

As a result of the reduced pump variance, Sampierana also reduces the administrative effort from development to assembly and logistics to service, including spare parts management and aftermarket. Feature updates and trouble shooting are efficiently carried out via the BODAS Service Tool, which among other things also includes a detailed guide to pump commissioning.