Decentralized Hydraulics II
In the previous project, an electro-hydraulic compact axis with a high-speed internal gear pump (HSIZP) was developed and integrated into an electro-hydraulic compact axis (EHA). With this, operation is only possible in one direction of rotation, which means that additional valve technology is required in the EHA. The aim of the research project is to further develop and optimize the EHA for reversing operation and to increase the achievable power density.
Benefit
- Increased power density of electro-hydraulic compact axes through high-speed components
- Decentralized EHA for mobile applications
- Reversible high-speed internal gear pump
- Efficiency increase through recuperation during operation
Procedure
- Further development and design optimization of the high-speed internal gear pump and EHA
- Simulations of the pumping process, the tribological contacts and the hydraulic circuit of the EHA
- Testing of the reversible HSIZP and the revised EHA
- Optimization of the pump and the EHA based on collected findings
Advantages of decentralized hydraulic supplies
In mobile machines, such as excavators, hydraulic power is usually provided by a central pressure supply in the vehicle. These usually consist of one or more pumps. The operator can control the actuators of the working hydraulics by means of valves. However, valve control causes some of the hydraulic power to be throttled and converted to heat. Hose and pipe lines are used to direct the hydraulic power to the individual actuators. This in turn results in line losses. A demand-oriented power supply with a variable-speed drive reduces throttling losses. A decentralized arrangement of the power supply, directly at the consumer, minimizes transmission losses in the lines and enables independent regulation of the pressure level as required.
Advantages of high-speed components in electrohydraulic compact axes
In mobile machines, such as excavators, hydraulic power is usually provided by a central pressure supply in the vehicle. These usually consist of one or more pumps. The operator can control the actuators of the working hydraulics by means of valves. However, valve control causes some of the hydraulic power to be throttled and converted to heat. Hose and pipe lines are used to direct the hydraulic power to the individual actuators. This in turn results in line losses. A demand-oriented power supply with a variable-speed drive reduces throttling losses. A decentralized arrangement of the power supply, directly at the consumer, minimizes transmission losses in the lines and enables independent regulation of the pressure level as required.
Objective
This research project aims to further develop the high-speed internal gear pump developed in the previous project and the associated electrohydraulic compact axis. The focus is on adapting the reversibility of the high-speed internal gear pump. This enables dynamic four-quadrant operation and thus energy recovery. Furthermore, the necessary complexity of the hydraulic system architecture is reduced and the required installation space is downsized due to the elimination of valves. The reversal of the direction of rotation implies a speed reduction to standstill and thus operation in the boundary friction range. The tribological contacts must be designed and optimized for the associated loads.
Acknowledgement
The IGF research project 22246 N of the research association Forschungskuratorium Maschinenbau e. V. – FKM, Lyoner Straße 18, 60528 Frankfurt am Main was supported from the budget of the Federal Ministry of Economic Affairs and Climate Action through the AiF within the scope of a program to support industrial community research and development (IGF) based on a decision of the German Bundestag