It is often the case that younger designers and engineers have hardly had any experience of hydraulics as part of their training. They are primarily concerned with software and think along digital lines. They are only really interested in the movements and the resulting data. Drive physics is what makes the difference in many cases here.
Hydraulics come into their own whenever large forces and robustness are required, however many young designers are not very familiar with this technology. Here are some facts showing why the use of modern, connected hydraulics is easier and more cost-effective than many of them realize:
These days, designers no longer have to have in-depth knowledge of fluid mechanics and fluid technology or deal with a plethora of individual components. They are increasingly using plug & produce modules such as servo-hydraulic axes with their own decentralized fluid circuit and a variable-speed pump drive. These ready-to-install modules simply need to be supplied with a current and connected to the control communication. Here’s why it makes sense: there is no drive technology that is more efficient, compact and robust than hydraulics at forces in excess of 400 kN.
Smart, connected hydraulics are commissioned with the same engineering tools as electric drives and control systems – at least Rexroth’s are. Functions previously carried out hydromechanically have long been handled by drive software instead. What’s more, software assistants guide technicians logically through the commissioning process and even suggest suitable parameters. What is important are the necessary forces – the rest is the same.
Until around a decade ago, power consumption was not a major consideration in mechanical engineering and plant construction. Hydraulic power units were constantly driven and provided maximum power at all times even when they were not needed. The preconception that hydraulics are more energy-intensive than other technologies therefore stems from that era. However, things have changed. Variable-speed pump drives generate the flow in line with demand and reduce speeds accordingly under partial load conditions. Compared to constantly driven pumps, they reduce power consumption by up to 80% – to a level consistent with that of electric drives of the same size.
Smart, connected hydraulics are extremely capable of communicating. As such, they depict the various stages with fine scaling: analog valves are very cost-effectively made digitally visible with IO-Link and exchange data with the control system. Smart valves with their own control electronics and field bus connection are just as convenient as electric drives. They are commissioned, operated and diagnosed via software. Plug & produce modules with their own control system also directly provide an OPC UA Client/Server for communication with higher-level IT systems. As such, connected hydraulics are already part of IoT in production.
What is the difference between current and hydraulic oil? One can only be measured whereas the other can be measured, sensed and seen. This is an advantage when you need to find out about operating states and deduce possible wear and expected life cycle on that basis. With a few pieces of sensor data such as pressure differential, oil temperature, optically measured contamination or pressure increase over time software can very accurately assess the condition of the system. Rexroth directly includes this kind of evaluation logic with the latest generation of hydraulic power units.
As one of the world’s leading suppliers of drive and control technologies, Bosch Rexroth ensures efficient, powerful and safe movement in machines and systems of any size. The company bundles global application experience in the market segments of Mobile Applications, Machinery Applications and Engineering, and Factory Automation. With its intelligent components, customized system solutions and services, Bosch Rexroth is creating the necessary environment for fully connected applications. Bosch Rexroth offers its customers hydraulics, electric drive and control technology, gear technology and linear motion and assembly technology, including software and interfaces to the Internet of Things. With locations in over 80 countries, more than 32,300 associates generated sales revenue of roughly 6.2 billion euros in 2018.
News release from Bosch Rexroth, 21/11/2019