A novel external gear pump based on tooth root-tooth tip flow distribution principle

To address the speed limitation of conventional external gear pumps (CEGPs) caused by inadequate oil suction efficiency, a novel external gear pump (NEGP) based on the parallel distribution principle of tooth root and tooth tip is proposed. By integrating oil suction pressurization technology, the operational speed range of the NEGP is significantly extended. Through experimental evaluation of CEGP's oil suction performance under various operating conditions and structural defect analysis, the NEGP design was developed and validated. A comprehensive flow field simulation model was established to systematically investigate the internal flow dynamics and identify key factors influencing suction efficiency. Furthermore, a dedicated pressurization centrifugal pump was designed, and integrated system tests along with full-scale flow field simulations were conducted to elucidate system matching characteristics and the underlying mechanisms of efficiency enhancement. Results demonstrate that at 3000 rpm, the oil suction efficiency of the NEGP is 12.1 percentage points higher than that of the CEGP. The suction performance of the NEGP is highly dependent on both inlet pressure and rotational speed. At low speeds, the suction contributions from the tooth root and tooth tip are comparable. However, at high speeds, suction at the tooth tip becomes dominant. With the assistance of the pressurization centrifugal pump, the stable operating speed of the NEGP is extended to 4000 rpm. The primary mechanism for improved efficiency is attributed to enhanced oil suction capability at the tooth root region due to elevated inlet pressure. NEGP exhibits lower power consumption and higher energy utilization efficiency than CEGP. • Propose a novel parallel flow distribution mechanism for high-speed external gear pumps. • Clarify the internal flow characteristics under the novel distribution mechanism. • Reveal the efficiency enhancement mechanism under inlet pressurization. • Extend the stable operating speed range from 2500 rpm to 4000 rpm.