Abstract:

A system, which used the capacitance sensor to measure the aperture of small blind holes, was studied. A capacitance probe with small diameter was used as the sensor. The capacitance instrument converted the change of the aperture in to the change of voltage signals which can be inputted into a computer through the USB interface to get processed. The working principle of the capacitance sensor and the electronic circuits of the capacitance instrument were discussed. The design scheme was also disserted as the system using the capacitance sensor to measure the aperture of small holes. The calibration of the sensor was done on the small blind holes with 3mm and 7mm aperture. From the analyzed experimental data, the resolution is 005μm, and the standard deviation of the experiments is within 05μm. 

Key words: small deep hole, capacitance sensor, calibration of sensor, driving cable

摘要：

采用电容式深孔内径测量仪测量机械加工过程中小深孔的孔径。该测量仪采用直径较小的电容探针作为传感器，电容探针通过采用驱动电缆技术消除了杂散电容的影响，将孔径的变化转换为电压的线性变化，并通过USB接口将此电压信号输入到计算机系统中进行处理。论述了小深孔内径电容式测量方法的基本原理，设计了电容式深孔内径测量仪测量小深孔孔径系统的总体方案。该方法特别适用于1mm~7mm深孔的内径自动检测，对3mm孔径进行了实际测量，并分析了测量所得到的数据，多次测量的标准差小于05μm，测量分辨率为005μm。

关键词: 小深孔, 电容探针, 传感器标定：驱动电缆