Thermo-elastic errors are one of the main drivers for reduced quality of workpieces in machining. Cooling systems can prevent these errors and improve quality. The paper describes a simulation method that takes into account both the temperature field of a machine tool frame and the fluid cooling system. Such simulations can help to improve the thermal stability of the machine tool frame.

Mass flow models for gaseous media describe the relationship between gas flow through throttle elements depending on pressure, temperature and type of medium. These models are used to calculate pneumatic components, to simulate pneumatic systems or to plan facilities. The known flow models are verified for ideal gases, such those as according to ISO 6358-1 (International Standard ISO 6358- 1: pneumatic fluid power – Determination of flow-rate characteristics of components using compressible fluids: General rules and test methods for steady-state flow, 2013). But they fail with real gases, especially at higher pressures. The objective of this contribution is to recommend a simple-touse model for the mass flow calculation of real gases. The advantage of the C and b model is the use of only two parameters. A testbench for high pressure up to 300 bar was used for model verification with air and hydrogen. The Library for standard dry air and hydrogen up to 1000 bar was used for the state variables of the real gases. The parameters C and b are obtained, applied and verified in the state space of real gas. With the C and b parameter it is possible to simulate not only the single component (valve, throttle, nozzle and so on) but also the whole system with a complete system simulation, like such as hydrogen filling stations.

aus dem Text: 'The term „industry 4.0“ describes the transition from a classic value-added chain to dynamic value-added networks. It is driven by four main design principles:  interconnection of machines and humans  information transparency  technical assistance to support humans  decentralized decisions This approach and its connected technologies, like IoT or cloud computing, enhance in the context of industrial production further flexibility and an increase in productivity through growing self-organisation and interlocking with logistics and planning processes. Extensive activities can be recorded in this field.

One development in the course of industrial digitalisation, which is being driven forward particularly in the German-speaking countries and will gain in importance in the future, is that of the Asset Administration Shell (AAS) [1]. The present work deals with the distribution, instantiation and use of those AASs for assets within the domain of a fluid power engineering application, which by themselves do not currently have the corresponding hardware and software for harbouring an AAS. The Business to Manufacturing Markup Language (B2MML) is used here for the deployment and instantiation of these AASs. In the present work, B2MML is extended with the concept definitions of AAS using its enhancement mechanisms. The distribution of the AASs to computing resources then takes place using B2MML and its transaction definitions. Furthermore, B2MML is used in a submodel to orchestrate process queues. In the course of the FL4 research project, B2MML is integrated as a partial model into the AAS and is used for orchestrating the Plug-and-Produce processes one the business and on subordinate levels.

Fluid Power displacement machines are still by far the dominant power transfer principles in mobile machinery. Power density, simple continuous variability for rotary and linear drives as well as straight forward repair and service concepts have enabled this technology a very successful development in the last decades. This general lecture will critically analyze if and how those drive line elements will be Key Elements of Future Technology in this market in the future, especially under the view that battery technologies are facing many challenges for powerful machines with intense duty cycles (see also automotive industry) [... aus dem Text].

Reducing the energy consumption of off-highway machinery due to poor system efficiency is an urgent challenge. Several advanced and innovative architectures have been proposed over the years to tackle this problem, but very few of them found fertile ground for commercial applications due to increased complexity and cost. In this paper, the design, implementation, and testing of a multi-service Digital Displacement ® Pump architecture applied to an excavator are presented. The Digital Displacement ® Pump allows for a dynamic physical displacement allocation to services at different pressure levels, thus reducing throttling losses required to operate multiple actuators simultaneously. A feed-forward control logic is implemented and applied to the system using a closed-centre architecture. The results indicate a fuel reduction of more than 30% compared to the baseline excavator.

Imagine a system with a pump driven by a speed-controlled electric motor. What and how much can be gained by using a pump with discretely variable displacement instead of a conventional fixed pump in such a system? This question is the focus in this paper, in which a simulation study based on a drive cycle for a loader crane is presented. The results indicate that the system efficiency from inverter input to pump output can increase by a few percentages. This might be considered small in relation to the increasing complexity that comes with discrete displacement. However, the results also show that a system with discrete displacement substantially reduces torque and cooling requirements on the electric motor. The required maximum torque can be reduced by 30 to 50 % and the motor can generate up to 40 % less heat since it can work in more efficient conditions. These potential benefits will be obtained with only a few discrete displacement settings available.

A new transmission is being designed for a next generation of large, offshore wind turbines, based on floating cup pumps and motors. The machines have a fixed displacement of around five liter per revolution. The objective of this study is to design, manufacture and test the pistons and cups of these machines. To this end, a new test bench has been designed and build, to measure the leakage and friction of the pistons up to a pressure level of 350 bar. Several sets of pistons and cups have been tested against a reference set which was proven to have very little friction at rated and peak operating conditions. The leakage between the pistons and cups was measured at different piston positions at stationary conditions. The friction between the piston and the cup has been measured continuously. From the tests it can be concluded that the friction force is below 0,01% of the piston force. The leakage losses are less than 0,5% of the total effective flow output.

Conventional electrohydraulic solutions integrate easily into modern machine concepts by utilizing field bus technology. Nevertheless, most use cases are limited to machine automation concepts. Integration into higher-level data and IoT systems is the key for positioning of electrohydraulic solutions within the factory of the future. CytroConnect is a new approach for the integration of electrohydraulic systems into IoT environments and the corresponding market offerings. Bosch Rexroth decided not only to integrate IoT-ready features like pre-installed sensor packages but also a modular automation concept providing decentralized intelligence with an open multi-ethernet interface. An edge-to-cloud connectivity stack operated by Bosch turns the target into a Connected Product. The convergence of physical and digital product can be realized. Based on that the digital service CytroConnect solves concrete holistic use cases like visualization and condition monitoring by offering a web-based dashboard of all relevant sensor data that is accessible everywhere. Modular paid add-ons offered as risk-free monthly subscriptions address further smart maintenance and prediction use cases.

Currently discussed trends and new technologies regarding cloud or edge computing imply that even most recent designs and functionalities of digital on-board-control electronics may be outdated and eventually will totally disappear. Additionally, those new technologies attract potential users by promises like new use cases e.g. predictive maintenance or a simplified architecture and reduced installation efforts. On the other hand, automation levels and subsequent requirements are often mixed up or discussed too generally. Nevertheless, what is the rue situation today and in the upcoming years? This paper elaborates the potentials of both approaches – state of the art on-board-control electronics and potentially disruptive control architectures for hydraulic valves in order to take the right decision and reflect the pros and cons for each topology by: a) Architecture of automation: In Terms of strongly hierarchical or multidimensional connected systems. b) Requirement of installation: By reflecting the dedicated ecosystems, on levels like plant, machine, subsystems. c) Maturity of technology: Looking on the user’s perspective. d) Safety and security: From legal and conformity aspects. e) Performance needs by specific task: In comparing standard to demanding real life applications.