Research On Inner Hole Measurement Technology Of Round Tubular Part

The measurement parameters of circular tubular parts inner hole usually include straightness, roundness and diameter. Because the length-diameter ratio of this kind of parts is large, and the hole space is narrow, which makes it difficult to measure the inner hole. This article analyzes the common measurement scheme and methods of the current round tubular parts and the inner hole of deep hole parts. Combined with the characteristics of the measured work piece, a measuring strategy has been made and a set of multi-parameter measuring device has been designed, and so have the measurement parameters for the evaluation and analysis.Measuring device body is set in hole, using the three points centered, and positioning principle implementation artifacts located at six, moving in the hole by external traction. The measuring device body is equipped with LVDT-probe and angle sensor. The LVDT-probe, driven by a motor can have rotating shaft rotation by the local axis of work piece, and have the measurement of roundness and diameter through the contact measurement methods. LVDT-probe and centering mechanism can be adjusted along the radial work piece, which makes it suitable for the different diameter of the work piece within a certain range, thus can improve the flexibility of the device using. Angle sensor is mainly used to complete the straightness measurement.It also includes the design of the control circuit, including:the design of using the implement of the roundness and diameter LVDT-probe and its signal conditioning circuit and A/D conversion circuit; the design of using the implement of the straightness measuring the Angle of the data acquisition circuit; the design of dragging the LVDT-probe rotation of motor drive circuit; the design of the main peripheral circuit and MCU communication interface circuit. It has completed the measurement and control system design and development program.It also has an evaluation and analysis of the straightness, roundness and the inner diameter. And the evaluation of straightness and roundness is made by using the least square method. Straightness pitch measurement method is studied in the segmentation strategy and optimization method of pitch, and it also analyzes the results of precision of Angle sensor and the straightness evaluation. Also, it analyzes the results of the precision of LVDT-probe, the mechanism of the accuracy of the location and the stepper motor vibration effects on roundness and diameter evaluation. Finally, the measurement of the instance is made.