Direct-Drive Gerotor Pump—A New Approach to Design of Hydraulic Pumps

This paper presents a new approach to the design of hydraulic pumps, exemplified by a prototype gerotor pump with an integrated direct drive, based on an original concept constituting the basis of the Polish patent PL 236677. One of the objectives of the study is to demonstrate that, despite the long-standing and widespread use of this class of devices, further development potential still exists. To this end, the study focuses on the experimental proof-of-concept validation of the proposed solution, specifically aiming to verify the correctness of the gerotor unit and the BLDC-type magnetic drive circuit design, and to assess the impact of direct integration on the pump’s hydraulic characteristics, thermal behaviour, and control performance. Emphasis is placed on demonstrating the feasibility of the presented solution and its potential for future practical applications. Accordingly, an experimental prototype direct-drive gerotor pump was designed and manufactured, together with a dedicated miniature test stand required for experimental investigations. The research programme comprised preliminary start-up tests, no-load operation, and pump operation under various operating conditions, including different rotational speeds and working pressures. The experimental investigations were successfully carried out, and the obtained results clearly confirmed the correctness of the proposed concept and the proper operation of the prototype. As discussed in the paper, the presented prototype currently exhibits specific limitations, primarily low efficiency and a limited rotational speed range. However, these represent typical early-stage issues that further development can relatively easily eliminate.