Research On New Measuring Methods Of Key Geometrical Parameters Of Hole And Shaft Parts

In the manufacturing of aerospace,shipbuilding,energy and power,hole and shaft parts are typical mechanical components.The matching accuracy of holes and shafts is one of the important technical indicators for this type of parts,which is directly related to the dynamic balance and sealing performance.Based on the guidance of dynamic and static measurement ideas,we take a systematic research of the wide-range and efficient new methods for measuring the key geometrical parameters in industrial sites,in order to meet the need for full inspection of the variety types of hole and shaft parts in the flexible manufacturing lines.With the research of existing measurement technologies and equipment for the diameter and concentricity measurement of holes part,and aiming at the rapid geometrical parameters measurement of serial holes with good tolerance,the paper describes a multi-layer measuring rod that installs a single laser displacement sensor(LDS)on each layer.This method is easy to implement by rotating the measuring rod randomly,and immune from detecting the measuring rod's rotation angles,so the overdetermined nonlinear equations of multi-layer holes can be established for fitting circles by LDSs' value.With the use of constriction factor particle swarm optimization(cfPSO),the diameters and concentricity of serial holes can be calculated by solving the optimal solution of the energy function of the over-determined equations.Through the diameter and concentricity measurement mathematical model of the measuring rod,we can simulate and analyze the error factors that affect the measurement accuracy during the experimental process,and the requirements for the installation accuracy of LDSs in the measuring rod can be calculated.In the tolerance of a certain installation error of the measuring rod,for the two different measurement targets of diameter and concentricity of the serial hole part,the LDS's laser direction is correlated with the central position of the hole to be measured.We can eliminate the calibration work of the LDS installation angle in the measuring rod for the diameter measurement,and which can significantly reduce the difficulty of the measuring rod method during operation.In the experiment,the diameter measurement validity of the method is verified,and the inner diameter measuring precision of 28 ?m is achieved by 16 ?m linearity LDS.Through a serial hole part consisting of three holes with a span of 240 mm,we realized 65 ?m concentricity measurement accuracy by the measuring rod.For the measurement of positional tolerance between the flat holes and shafts plane,we select an ICE crankshaft with complex topography as the measuring object.In order to measure the positional relationship between the flange end holes and the journal plane of the crankshaft,a method and device for quickly measuring the position of the flange end hole group is proposed in this paper.We use multi-camera to measure the high precision coordinates of the flange end holes of the crankshaft,and the position information of the reference plane of the crankshaft journal relative to the flange end is obtained by using pneumatic inductive displacement sensors.Through the coordinate system conversion,the coordinate of the flange end holes is integrated into the global coordinate system of the crankshaft journal plane,and the positional tolerance of the flange end holes relative to the journal plane can be finally obtained.For the full-inspection of key geometrical parameters of hole and shaft part,we can conveniently implement the methods mentioned in this paper in industrial sites with the advantage of strong adaptability.In engineering practice,they are easy to integrate into the engine's flexible automated production line for rapid detection of the crankshaft and cylinder.