LAUSR

This study proposes a new type of tri-screw pump, which has a 1:2:3 ratio of the active diameter of the screw, the diameter of the pitch circle, and the top diameter of the active screw. Fixed width correction method of the driven screw is also proposed to avoid wear of tooth top. The mathematical model of active and driven screws is established. To avoid the wear of the tooth top arc, several transition patterns are proposed, and the transition curve in the form of a circular arc is deduced. The designed screw curve is grinded, and the tri-screw pump is assembled. The hydraulic pump test bench is tested using the overflow valve to perform pressure loading of 3–5 MPa on the outlet of the screw pump. The outlet flow rate and pressure are tested, and results indicate that the output flow of the pump conforms to the designed flow rate. This study establishes the detailed equation of the end face profile of the tri-screw pump (active and driven screws) and corrects the arc profile of the line angle.