A new variety of axial piston hydraulic machines with multi-row units and a dual oscillating unit

Abstract

The possibility of increasing the working volume, power, specific energy capacity (energy efficiency), and acceleration response of hydraulic machines under reduced supply and torque pulsation is investigated. The research methodology included the geometric, kinematic, power, and energy analysis of a four-row axial piston hydraulic machine with a dual oscillating unit and without an end distribution system. As a result, a new type of compact rotary hydraulic machines with volumetric action was created. In the proposed model, each subsequent row of cylinders is located in the inter-cylinder space of the previous cylinders with smaller radii. Such a design provides for a 24.5-fold increase in the working capacity and power of a hydraulic machine compared to a single-row design, as well as an increase in the acceleration response in the hydraulic motor mode. The elimination of end distribution systems excludes the possibility of violation of joint tightness between blocks and distribution disks due to block overturning by piston centrifugal forces at high rotation speeds and a multiple reduction of supply and torque pulsation. It was established that the increase in the specific power capacity of a hydraulic machine depends on its particular implementation, potentially reaching 18–25 kW/kg. The abovementioned features of the proposed axial piston hydraulic machine with a dual oscillating unit ensure the compactness of oscillating units, minimum dimensions of the cylinder blocks, and the hydraulic machine as a whole, resulting in its minimum mass and maximum specific power capacity.