Study On An Internal Driving Steering Gear

This paper is about the key technique of the project of ChongQing scientific technology which called"the key technique and industrialization of the intelligent hydraulic steering gear",and the project number is CSTC 2008AB3037, which need to develop a new type hydraulic steering gear used on naval vessel. In order to meet the request,basing on the reversing-ball-screw mechanism which can expansion the force,the author innovatively put the whole driving structure of the steering gear inside the upper rudder stock,and then an internal driving steering gear was born,which has been applied the patent of invention,the invention patent number is ZL2004100106.8. The most valuable merit of the steering gear is reducing the using space of the steering gear room as small as the volume of an axle,in this way it can save 80% space of the steering gear room. Comparing with the other steering gears,the internal driving steering gear is dominant in torque characteristics, sealing, reliability and efficiency. It can be used in all kinds of domestic and international shipping,especially the submarine vessel. In this paper, basing on the reversing-ball-screw mechanism, the author designed the internal driving steering gear which meet the requests of the project and produced some prototypes to take experimental research. The major research is listed as follows:①The research status and main feature of every kind of steering gears in existence are introduced, especially the research status and developing trend of the reciprocating steering gear and rotary steering gear are analysised detailedly. And connecting with the requests of the subject,the main research contexts are presented.②The theory of reversing-ball-screw transmission is introduced. And then the internal driving steering gear is presented basing on the theory. The principle and structure of the internal driving steering gear are described. The statics and dynamics of the mechanism are analysised. At last, the characteristic of the mechanism is concluded.③In order to prepare theory support for the design of the mechanism,the kinetic characteristic,equivalent model,static load and efficiency of rolling screw pair , an important component of the internal driving steering gear, are analyzed. And using the theory of Hertz contact, the elastic contact station of the screw pair is analyzed. The rigidity formulas of the mechanism are deduced to serve for checking the rigidity of the mechanism and the better choice of every parameter is introduced to serve for optimizing the mechanism. ④Following the theory analysis, the designing method and the strength and rigidity checking method of the mechanism with big helix angle is presented. And meeting the requests of the subject, the internal driving steering gear with high power density is designed. The design process,strength and rigidity checking process,and the innovating structure of the steering gear is described. At last, the hermetic seal of the mechanism is introduced.⑤Build the solid model of each component of the internal driving steering gear and assemble them by the 3D design softwafe named Pro/Engineer. Then transform assembling model to ADAMS software and set up the Virtual Prototype model of the internal driving steering gear to do dynamic simulation to prove the rightness of the mechanism principles. Analyzed the finite element of the internal driving steering gear by using ANSYS Workbench, then elict maximum principal elastic strain chorogram, maximum principal stress chorogram and deformation chorogram of each component. The dynamic characteristic of the internal driving steering gear is analyzed through finite element method and the restrain modal is solved.⑥Aiming at the difficulty of machining internal spiral groove with big lift angle, several methods are presented. The prototypes are processed and some experiments on the prototype in load, output range of rudder movement angle and time of rudder movement are taken.⑦Carry a summary to the main research work in this paper, and then give some prospect to the further research.