New Matrix Pump Switching Component for Excavator's Flexible Oil Flow Management

In recent years many studies were performed with the aim of reducing losses and to optimize the oil flow management in complex machines like excavators. One of the most promising ideas is to implement multiple hydraulic power sources but this requires a flexible pump switch system, in fact depending on flow request and machine mode one or more pumps can be switched to serve each actuator. To put into practice these studies it is necessary to in-depth design the distribution system, through which hydrostatic transmissions are applied to the different loads. The system presented couples more actuators to every single pumps and offers also cross connections, in order to increase systems flexibility in flow management. The paper presents a new component to realize the pump switch management, applying the matrix concept to the hydraulic flow connections. The matrix for oil flow management is a new hydraulic component, flexible, safe and scalable, that can be coupled to other similar, offering a real matrix of lines and columns. From the working principle point of view, each line is connected to a pump and each column is connected to a load, only a section can be opened for each pump, but more connections can be opened for an actuator, offering a flexible flow management. The component is a rotating distributor with a safety spool, that can connect P and T port of one pump to the A and B port of each actuator, moving the safety spool only when the rotary distributor is coupled with the desired actuator. Both closed center and open center configurations are possible, as well as regenerative systems can be implemented. The solution is presented with focus on the mechanical design and on the working principle, offering an optimal solution to the switching system, that free the distribution system design from the constraint of a predefined coupling of pumps with actuators. Since the component is in its early stage of development, the paper will focus mainly on design concept and architectural alternatives and potential benefits of the implementation of the concept on state of art architectures from the functional capability point of view. Some argument will be given then on the topic of Functional Safety disclosing some of the operability and safety potentials of the system. Further important design aspects such as Internal Leakage, Axial and Radial Forces on Spools, Dynamic Response will be addressed in later publications, as well as system simulation of working cycles and Testing of Prototype has to be obviously undertaken in the future.