Design And Analysis Of The External Involute Gearing Pump

Gear pump is very important in the hydraulic system, which is the power source toensure the work of hydraulic system. Relative to the other structure of pump, Gear pump hasadvantage of simple structure, light weight, low price, simple to be made, easy to maintenance,can change speed in large range, system is not sensitive to oil pollution, so it is widely used inmechanical systems. Mechanical engineering has also raised a lot of new requirements to gearpump, Such as high pressure, large displacement, low ripple and noise, so the performanceanalysis and improvement of the gear pump have become very important subjects. In thispaper, I will analysis the flow characteristics and radial meshing force of the gear pumps, andthen deal them with some numerical calculation, provide the necessary theoretical for thedesign of the gear pump.1. According to the principle of involutes’ formation to get the tooth profile and meshingline equation. Analyzed the degree of coincidence and meshing sliding of gear mesh.2. Calculated the flow between interdentally area, gear meshing area, and eventually theflow of the gear pump. Getting the pump flow rate when determine the time and speed. Thestructure of gear pump has a great influence on the internal flow field, using fluent finitevolume method to establishing the calculation model; get the pump different characteristicson different center distances and speeds. The result is:(1) Oil inlet pressure is low than thepressure of oil outlet, Fluid pressure changes periodically, trapped oil appeared between thegear meshing pairs.(2) The smaller (bigger) the center distance, the bigger (smaller) theaverage speed at the export, and the pressure difference at the import and export gets bigger(smaller), the trapped oil pressure is higher (lower) too;(3) The export velocity and the rotatespeed take on a linearly proportional relation. A slightly large center distance can reducetrapped oil pressure.3. Through theoretical analysis can know that the pressure around the gear changes incircumferential, radial force of hydraulic is asymmetric, and it is verified by numericalsimulation. Due to the meshing of there is interaction meshing force between the two gears,then got the gears meshing force and torque by calculate. Analysis gear meshing stress by thefinite element method and using ansys software, get gear stress distribution, provide referencefor the design of the pump.4. This paper discussed the parameters of the gear pump, the basic structure of the gearpump will be able to determined when just make sure the number of teeth, modulus, tooththickness, then discussed the most critical step in the design of pump. Analyzed the maincauses of the trapped oil, and gives out the solution of it, designed unloading tank. Give out corresponding reduction of radial force according to the calculation method of radial force.Establish the designing parameter optimization as the object of flow pulsation.