The rotor (gear) profile of the external meshing gear pump, enclosed by the pump casing, forms a series of sealed chambers. During the meshing operation, it conveys fluid from the low-pressure zone to the high-pressure zone, creating suction and discharge. The sealing characteristics of the rotor profile at the tooth crest and root affect the pump's internal leakage and volumetric efficiency. The volume of the formed sealed chamber influences the pump's volumetric efficiency, cavitation, hydraulic vibration, etc. The meshing characteristics of the profile between rotors determine the transmission characteristics of torque and motion, subsequently affecting factors such as tooth contact stress, friction wear life, mechanical vibration and noise, and mechanical efficiency.
Considering the convenient manufacturing processes and design algorithms, the involute tooth profile has been widely adopted in the industry. However, the evident drawbacks of the involute rotor profile include low space efficiency (smaller displacement for the same size) and limited effective sealing width, along with the issue of oil entrapment.
The Composite Integral Algorithm developed by APT breaks through the constraints of traditional profile solutions. It allows the use of more complex curves and segmented curves as base functions for solving rotor pair profiles. Compared to traditional involute rotor profiles, the new series of rotor profiles based on the Composite Integral Algorithm can be highly flexible in multi-parameter optimization. Depending on actual working conditions and technical requirements, optimization of volumetric efficiency, sealing performance, pressure pulsation, cavitation characteristics, etc., can be done on-demand. Moreover, it fundamentally eliminates the problem of oil entrapment, enabling the external meshing gear pump to achieve better hydraulic performance, transmission performance, and reliability.
The rotor profile types of the external meshing gear pump developed by APT are illustrated in the images above, with various profile types already maturely applied in the automotive and aviation industries. APT can also customize new specialized profiles according to customer-specific technical requirements.