| In recent years, with the development of new materials and manufacture technology,water hydraulic transmission technology has made considerable progress and development.Water hydraulic motor as a kind of energy conversion device and autuator play animportant role in water hydraulic transmission system, and also is a research hotpot towhich the scholars pay attention. At present, most achievements of water hydraulic motorfocus on water hydraulic axial piston motor and vane motor, while in water hydraulicmotor with low speed high torque, it’s very few. Where the measuring space is limited,great torque is required and gearbox is inconvenient installation, hydraulic motor with lowspeed high torque becomes more important. Studying on the characteristics and keytechnology of water hydraulic motor with low speed high torque has positively theoreticaland practical applications. For these reasons, selecting incurve multiple-acting type waterhydraulic motor with low speed high torque as the research object, the clearance of keyfriction pairs, material selection, the friction and wear have been doing through theoreticalanalysis and experimental study. The purpose of the thesis explores solutions to the keytechnical problems of hydraulic motor with low speed high torque which uses water asworking medium. And this will lay the foundation for its practical application.First of all, based on the kinematics and dynamics theories, the stator curve of waterhydraulic motor is calculated and analyzed. The ultimate goal is to find the right statorcurve for water hydraulic motor with low speed high torque which has the characteristicsof small impact, low contact stress value, stable running, etc. And based on therelationship between temperature rise and pressure drop, viscosity-temperature equation,viscosity-pressure equation, the equilibrium equation and flow equation, the static anddynamic performance, power loss, water film thickness and leakage flow of piston pair areresearched when piston pair is concentric and eccentric with rotor cylinder block at lowand high rotational speed. And the influence of water viscosity on leakage flow loss ofpiston pair and the influence of the water film thickness on the piston pair are further analyzed. Meanwhile the structure of piston pair, with the minimum of the total powerloss of piston pair as objective, is designed.Secondly, according to the principle of hydrostatic pressure bearing, the workingcharacter of port plate is calculated and analyzed. The aim is to find out a suitable waterfilm thickness for port plate and rotor. In order to ensure the volumetric efficiency ofwater hydraulic motor, the effects of clearance, temperature and rotate speed on flowdistribution performance of water hydraulic motor are analyzed in detail based on thepressure-flow equation. On this basis, thrust characteristics of port plate in water hydraulicmotor is studied. And this ensures that the residual pressing force of the end face of portplate and rotor meet the design requirement of the residual pressing force of friction pairin water hydraulic transmission.Thirdly, based on the materialogy and tribology theories, the friction and wearproperties of different matching materials under seawater lubrication are investigated.Taking the friction coefficient, temperature rise of seawater, the morphologies of the wornsurfaces, wear rates and wear depth as evaluation index, the optimum counter materialsare investigated. The aim is to find the right the counter materials of kinematic pairs forwater hydraulic motor with low speed high torque.Finally, the principle prototype of water hydraulic motor is designed and made on thebasic of these studies. To analyze the characteristics of prototype, no-load and loading testare respectively carried out. This could verify the correctness and feasibility of the theoryof design, method of design, structure and selection of materials of the developed waterhydraulic motor with low speed high torque. |
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