基于运动合成的活塞异形销孔加工新原理及关键技术研究

随着发动机转速及功率的提高，活塞异形销孔以其均布销孔应力、提高活塞寿命的优点得到了广泛应用。而以椭圆形销孔为代表的异形销孔其加工方法却并不能令人满意。目前椭圆销孔的加工方法需要在镗杆上安装辅助进给机构，存在系统结构复杂、控制困难等问题。本项目利用静压主轴轴心的公转运动与刀具的自转运动合成直接得到椭圆刀尖轨迹，从而实现椭圆销孔加工。研究轴心公转轨迹为坐标轴上线段时，两运动的合成机理以及销孔加工方案。研究新型静压轴承的结构及优化参数，在此基础上研究轴心轨迹的液压控制机理及实现方案。研究伺服阀对轴心轨迹的作用机制。研究润滑油粘度、温度等特性对轴心轨迹的影响。构建系统动力学模型，研究刀尖轨迹的开环和闭环控制理论。研究建模误差或外干扰时控制策略的抗干扰性、响应速度等特性。开展刀尖轨迹的试验控制，以某型号活塞销孔为例进行加工研究。本项目的实现将为新方法在活塞异形销孔加工上的应用奠定理论基础和试验依据。

As engine rotation speed and power increase, non-circular pin hole of piston is widely used for its homogenized stress of pin hole and increased piston lifespan. Elliptical pin hole is one of representative non-circular pin holes, but its machining methods are not satisfactory. At present, machining methods of elliptical hole need install auxiliary feeding mechanism on boring bar, with such disadvantages as complex system structure and controlling difficulty. This project will use motion synthesis(between revolution of the hydrostatic shaft center and rotation of the tool nose) to directly obtain the elliptical tool nose orbit, and thus, the machining of elliptical hole can be achieved. When shaft center revolution orbit is line segment in axis, the synthesis principle of two motions and pin hole processing scheme will be studied. The project will research the new hydrostatic bearing structure and optimization parameters, and give a study on the hydraulic control mechanism and implementation scheme. The working mechanism of servo valve on shaft center orbit will be studied. This project will also research influence of lubricating oil viscosity and temperature on shaft center orbit, build the system dynamics model, and study open-loop and close-loop control theory of tool nose orbit. The research will focus on the anti-interference and response speed of control strategy under the condition of modeling error and external disturbance. The project will carry out the control experiment of tool nose orbit, with some type of piston pin hole as an example to be studied. The realization for the project will lay theoretical and experiment foundation for the application of new method for boring of non-circular pin hole of piston.