Efficient, Intelligent, Compact and Quiet Hydraulic Power

Compact size, energy efficiency, low noise levels and connectivity: these are the relevant properties of CytroBox, the new smart hydraulic power unit by Bosch Rexroth. With an intermediate power range from 7.5 to 30 kW, the power unit is used in all production environments: from machine tools to test machines, right up to presses.

by Silvia Crespi

By introducing CytroBox, Bosch Rexroth presents a hydraulic power unit designed to satisfy the intermediate power range from 7.5 to 30 kW. The “Energy on demand” concept is implemented by means of the use of variable speed pump drives which adapt individually to flow system demands; in other words, the number of revolutions in conditions of partial or absent load is reduced, while it is increased when fully loaded.
This allows energy savings of up to 80% of energy compared to constantly driven power units.
The high degree of efficiency of the manifold block, manufactured using 3D sand core printing method, also contributes to efficient operation. With this additive manufacturing method, the manifolds block is up to 40% more compact and has improved flow channels.
This improves the oil flow, reduces pressure losses and minimizes the areas where leaks could occur ad fewer plugscrews are required.
Bosch Rexroth presented Cytrobox at the SPS IPC DRIVES Italia trade show.
We went into further technical detail with Riccardo Patat, Hydraulics Manager, Bosch Rexroth: “CytroBox – he explained – aims at representing a modern compact hydraulic solution, which goes beyond traditional hydraulics, with a sharp focus on energy efficiency.
Instead of the classical asynchronous motor, a synchronous motor has been installed, coupled with an axial piston pump, which ensures flow to the system. This solution allows to provide energy on demand”.

Tank size reduced by 70% with the same performances
The compact design and the reduced footprint of CytroBox have been obtained also by means of the optimization of the tank design based on Rexroth MyCro technology. Thanks to the CFD simulation, the volume of the oil is reduced by 75%, from 600 to only 150 litres.
It is also possible to save space by using specific synchronization techniques. Water-cooled synchronous motors are up to 80% smaller with respect to comparable induction motors.
All functions are concentrated in a compact cabinet, such that CytroBox may be integrated with flexibility and minimum footprint on
pre-existing production lines. “We managed to reduce considerably the size of the tank, the very heart of the power unit – Mr Patat continued – while keeping the same performances: from a 2 square metre size we went down to 0.5 square metres. This was possible thanks to the intensive use of simulations in the design phase. Internal geometries obtained allow the oil to be degassed in a very short time. As a result, the CytroBox can be integrated into existing production lines in a flexible, space saving manner”.

Smart integration for Condition Monitoring
CytroBox is equipped with a package of sensors and open interfaces; it is destined fr use in integrated environments. Sensors provide information regarding the current status filter, oil and drive condition.
Data collected are duly reprocessed and turned into useful information for production processes; thanks to Open Core technology data are always available.
The sensor package, which may be integrated with Rexroth’s hydraulic unit, allows technicians full visibility of all the information concerning the functioning of CytroBox: from the state and operative condition of components to alerts regarding urgent maintenance, right up to the predictive maintenance analysis, users have all data readily available.
Riccardo Patat provided further details in terms of connectivity too: “CytroBox was designed to be inserted in an Industry 4.0 context; connectivity, therefore, was a necessity.
The power unit is equipped with digital hydraulic sensors such as tank level and temperature indicators, pump leakage indicators, indicators which show the presence of air and water in the oil, particle counter to monitor the classification of the oil itself.

All of these sensors communicate using
IO-Link interface. Digital information is managed through the drive and are filed within CytroConnect, the Bosch Rexroth software which allows the user to view through the dashboard the state of health of the unit, with all the relevant values of its components. Information is stored and may be used at a later time, thanks to the presence of the IoT gateway which, besides filing data, processes them and makes them available to enable both an optimized maintenance scheduling and an additional innovation on the machine: knowing how the operative conditions of the machines vary, it is possible to bring about improvements to ensure an increasingly remarkable productivity and product quality”.

Lower acoustic emissions for a greater use comfort
Let us conclude with acoustic emissions: noise generated by the hydraulic unit is absorbed by the compact disposition of all components in a single body and by the inbuilt sound insulation components. Thanks to these properties, sound is not spread on the outside.
To further reduce noise emissions of the hydraulic power unit the motor-pump group is directly mounted on a polymeric material basement. The sound emissions of CytroBox – even when fully loaded – are therefore lower than the 85 dB(A) of comparable traditional power units.
Action taken and costs borne to diminish noise levels decrease drastically, allowing operators to work even in the immediate proximity without any problems.

A constant quality of products over time
CytroBox may be used in all sorts of production: from machine tools to test apparatus right up to presses and, more in general, in any production concern where a hydraulic power unit with installed power ranging from 7.5 to 30 kW is needed and where one hour of machine downtime causes a considerable economic damage. “Let us think about a press for rubber vulcanizing – Mr Patat concluded – a sturdy and stable hydraulics guarantees a constant target quality over time. CytroBox is the answer for the hydraulic part of this machine”. CytroBox is included among enabling Industry 4.0 technologies which may be the object of hyper-amortization foreseen by the national 4.0 plan.