Displacer instead of throttle control
Modern hydraulic system solutions require often significantly less hardware components because tasks which have been carried out by the valve technology in the past, are now done by the software. The classic throttle control with valves is replaced increasingly with an intelligent displacer control with variable flow via internal gear pump. Speed variable pump drives control hydraulic functions from the software-controlled speed, partially in addition by the adjustment of the swivel angle for axial piston units.
Therefore, OEMs are able to implement completely new concepts. So far, a big central aggregate supplied many hydraulic cylinders with a big oil quantity. Valves where used to control the functions and synchronize the actuators. Now, system manufacturers can use hydraulic single drives. Speed variable pump drives create the flow for only one cylinder. The synchronization of these axes is done via software in real time. This saves a lot of piping effort and many valves. In particular, the commissioning effort is reduced significantly. Process changes require only the input of optimized parameters via the operating software.
Servo-hydraulic linear axes
Servo-hydraulic linear axes, ready to install, take it one step further: These ready-to-install modules consist mainly of a speed variable pump drive, a cylinder mounted on it and a decentralized hydraulic circuit. This way, the axis does not need a separate power unit. Pumps are driven with variable-speed and by the same servo motors as the electromechanical linear axes. Since the hydraulic axes are enclosed self-sufficient systems, technicians only need to connect the power and communication cable during installation and commissioning. Everything else, such as the parameterization values determined in the simulation, is already saved in the drive software and support the plug & run philosophy. This way, handling of servo-hydraulic axes is identical to the handling electro-mechanical ones. This gives machine manufacturers the possibility to scale drive forces and properties with minimum energy requirement.
Quick networking and flexible configuration
For complex hydraulic systems, commissioners need to define up to 1,500 parameters. This effort can be reduced drastically if the hydraulic know-how is saved in the decentralized control systems. Autotuning-functions and commissioning assistants can reduce the number of parameters to be defined to only 50. “Electronic name plates” incl. technical parameters on intelligent component contribute to this. An automated commissioning and user-independent optimization obligatory requires local intelligence in the components. First manufacturers have already developed uniform and completely technologyneutral engineering tools for commissioning, parameterization and diagnosis of electric, electrohydraulic and electro-mechanical drives. This results in the fact that no specific knowledge about hydraulics is required for commissioning and parameterization of the pre-defined controllers. The software suggests with its corresponding assistant those parameters which guarantee sufficient system performance in most cases. Intelligent, networkable hydraulics is in terms of automation technology comparable with electromechanical or electric axes and offers in addition all physical advantages of the fluid technology.
Low total cost of ownership
For end users, the total costs of ownership are most important. They are the product of purchasing and operation costs, the maintenance effort and availability. For operation costs, the power consumption plays an important role. The availability includes set-up times for ever decreasing batch sizes and downtimes due to required repair works. Intelligent, networkable hydraulics reduce the costs of all factors.
80 percent more energy efficient
The electrification of the hydraulics provides for the networkability and makes them more energy efficient. This way, variable speed pump drives reduce the power consumption by up to 80 percent while maintaining the performance and are thus in the scale of electric drives. By combining electrohydraulic single drives, all possibilities of oscillating process energies can be used, i.e. the recovery of brake energies and need-based supply and recovery. The need-based creation of the flow will increase the service life of the hydraulic media and the used hydraulic components. This will additionally decrease the operational costs. The introduction of condition monitoring and predictive maintenance increases the “Overall Equipment Efficiency” with improved availability and lower maintenance costs.
Intelligent, networkable hydraulics fulfill all requirements for the use in Industry 4.0 concepts: distributed intelligence, open standards, digital life cycle management, quick interconnection and flexible configuration as well as a virtual real time image. This provides for a seamless integration into a horizontal and vertical network which provides for a blend of real automation with the virtual world of the information technology and the Internet in Industry 4.0. At the same time, it keeps the unique physical features such as force density, compactness, overload capacity and ruggedness. The challenge is to convert the additional costs for electronics and sensor technology into measurable customer advantages and especially to develop the software to a point that handling the fluid technology will be further simplified. This way, intelligent networkable hydraulics reduce the energy expenses for OEMs and reduce the total cost of ownership for end users.
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