Automatic Transmission Hydraulic Pump Test Procedure

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.

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Optimal Efficiency Shift Schedule of Automatic Transmission for Construction Vehicle

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.468-471.2403 ◽

2012 ◽

Vol 468-471 ◽

pp. 2403-2408

Author(s):

Huai Liang Kang ◽

Jie Gong ◽

Ding Xuan Zhao ◽

Tian Yu Li

Keyword(s):

Working Conditions ◽

High Efficiency ◽

Automatic Transmission ◽

Vehicle Speed ◽

Hydraulic Pump ◽

Wheel Loader ◽

Dynamic Simulation Model ◽

Simulation Results ◽

Optimal Efficiency ◽

Pump Pressure

The working conditions for construction vehicles (wheel loader, bulldozer, etc.) are very complicated and the operating loads change frequently and sharply. This result will lead to lower powertrain efficiency. In order to maintain the high efficiency of construction vehicles equipped with automatic transmission, an optimal efficiency shift (OES) schedule with 3-parameter (vehicle speed, throttle opening, and hydraulic pump pressure) is proposed and designed by creating and analyzing the powertrain model. A dynamic simulation model using the OES schedule for the construction vehicle has been established by MATLAB/Simulink. The simulation results show that the 3-parameter shift (3PS) schedule is superior to the 2-parameter (vehicle speed and throttle opening) shift (2PS) schedule in energy saving.

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