Non-contact three-point circular hole inner diameter measuring device and method

Abstract

The invention belongs to the technical field of material measurement, and discloses a non-contact three-point circular hole inner diameter measuring device and method. The device comprises three laser displacement sensors, sensor supporting frames are fixedly installed on the outer sides of the three laser displacement sensors correspondingly, two-axis tilting tables are fixedly installed at the bottoms of the three sensor supporting frames correspondingly, the bottoms of the three two-axis tilting tables are fixedly provided with two-axis translation tables, workpiece bearing seats are placed at the bottoms of the middle areas of the break angles of the laser displacement sensors, and the tops of the workpiece bearing seats are fixedly provided with measured circular hole workpieces. Non-contact point measurement based on the quadrangular frustum reflector is adopted, a sensor probe does not need to be placed in a measured aperture, the device and method are suitable for measuring the inner diameter of a small-aperture workpiece, and the surface of the workpiece is prevented from being damaged due to non-contact; when a workpiece to be measured is placed, strict centering operation of the workpiece and the quadrangular frustum reflector is not needed, and the measurement efficiency is improved.

Description

technical field [0001] The invention belongs to the technical field of material measurement, in particular to a device and method for measuring the inner diameter of a circular hole at three points without contact. Background technique [0002] In the precision machining process of the inner hole of the round hole workpiece, the diameter of the inner hole is an important performance index to measure the processing quality of the workpiece. Most of them use plug gauges, three-jaw inner micrometers and three-coordinate measuring machines, etc., but these methods are all contact measurements, which are easy to cause damage to the surface of the workpiece, and require manual operation. The measurement efficiency is low, and it is difficult to achieve fast and non-destructive automatic detection. Although the measuring instrument is a non-contact inner diameter detection method, it is limited by its short working distance, and it is easy to come into contact with the workpiece to...

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Problems solved by technology

[0002] In the precision machining process of the inner hole of the round hole workpiece, the diameter of the inner hole is an important performance index to measure the processing quality of the workpiece. Most of them use plug gauges, three-jaw inner micrometers and three-coordinate measuring machines, etc., but these methods are all contact measurements, which are easy to cause damage to the surface of the workpiece, and require manual operation. The measurement efficiency is low, and it is difficult to achieve fast and non-destructive automatic detection. Although the measuring instrument is a non-contact inner diameter detection method, it is limited by its short working distance, and it is easy to come into contact with the workpiece to be measured, which will cause surface damage. The image measuring instrument is a non-contact measurement, but Limited by the detection range and resolution, the general accuracy is difficult to reach below 5 microns, and the instrument is large in size, which makes it difficult to realize automatic measurement on the industrial site. Therefore, it is necessary to develop a high-precision online measurement device and method for the inner diameter of round hole workpieces. Realize on-site rapid and non-destructive measurement of the inner diameter of round hole workpieces

[0003] Another problem in inner diameter measurement is that for small hole workpieces with an inner diameter of five millimeters to tens of millimeters, conventional diameter detection instruments cannot penetrate into the inner hole, resulting in difficulty in measurement. Japanese patent (JP 2011-196899A, 2011.10. 06) discloses a three-point internal diameter measuring device based on a triangular reflector. The three laser beams are first shot from the outside of the workpiece to the triangular reflector placed inside the workpiece along the axial direction of the workpiece to be measured. The three laser beams are respectively The three reflective surfaces of the triangular reflector are horizontally directed to 3 points on the same horizontal section on the inner wall of the workpiece, and the reflected light is then emitted to the workpiece through the triangular reflector, and the displacement of the laser is obtained by analyzing the external receiver of the workpiece. Finally, the measurement result of the inner diameter of the workpiece is obtained by the principle of 3-point fixed circle

[0004] CN105043278B patent discloses a non-contact 3-point or 4-point method for measuring the inner diameter of a circular hole. 3 or 4 laser displacement sensors are arranged inside the workpiece to be measured at a certain interval, and the measurement optical axis of the laser displacement sensor is adjusted. , so that it meets certain preset conditions, and then the radius of the measured circular hole is obtained according to the circumscribed triangle formula; the above two patents all assume that, through the adjustment of the optical axis, the extension line of the laser measurement optical axis on the radial section of the workpiece It can be intersected at one point, but in practice, it is difficult for the laser measurement optical axis to fully meet the condition of intersecting at one point through adjustment, and a small deviation angle error of the laser optical axis will have a greater impact on the measurement results

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