JP6131610B2 - Circular workpiece diameter measurement method - Google Patents

Description

The present invention relates to a diameter measurement method for a circular workpiece, and more particularly to a diameter measurement method for a circular workpiece that can accurately measure the inner diameter and outer diameter of a circular workpiece that is displaced in the radial direction.

  As this type of diameter measuring method, for example, there is a method disclosed in Patent Document 1. In this method, the displacement sensor is turned toward the inner peripheral surface of the circular workpiece to obtain the entire circumference shape of the workpiece inner circumference, and the workpiece center position and inner diameter are calculated from the entire circumference shape.

JP 2003-254742 A

  However, in the above-described conventional method, if the center of the circular workpiece is displaced from the turning center of the displacement sensor, that is, if the circular workpiece is not positioned accurately, a measurement error occurs, and vibration occurs when the displacement sensor is turned. There is also a problem that a measurement error occurs.

Accordingly, the present invention solves such a problem, and can prevent a decrease in measurement accuracy due to vibration without turning the detection unit, and can achieve high accuracy even when the position of the circular workpiece is deviated from a predetermined position. Another object of the present invention is to provide a circular workpiece diameter measuring method capable of measuring the inner diameter and / or outer diameter of a circular workpiece.

In order to achieve the above object, in the diameter measuring method of the present invention , the circular workpiece (W) is displaced in a direction that linearly crosses the circumferential surface at a plurality of circumferential positions of the circular workpiece (W) (E1 to E4). ), A step of determining the center (O) position of the circular workpiece (W) based on the detected shift amount of the position shifts (E1 to E4), and the determined center (O) position. A step of measuring at least one of an inner diameter (D1) and an outer diameter (D2) of the circular workpiece (W) on a straight line passing through , and placing the circular workpiece (W) on the rotary table (1). By rotating around the rotation axis (Ax) of the rotary table (1), radial positional deviations (E1 to E4) are detected at a plurality of circumferential positions of the circular workpiece (W), Rotation axis (Ax) circumference of rotary table (W) A two-dimensional displacement sensor (2) for detecting the displacement of each point on a straight line of a certain length in the radial direction of the rotary table (W) is disposed at one circumferential direction of the rotary table (W). The deviation of the surface feature point (Wp) position from the center position (As) of the straight line is defined as the radial position deviation (E1 to E4).

In the present invention , since it is not necessary to turn the detection unit, a decrease in measurement accuracy due to vibration can be avoided. Further, since the center position of the circular workpiece is determined based on the detected displacement amount, even if the position of the circular workpiece is deviated from the predetermined position, the inner diameter or outer diameter of the circular workpiece is accurately determined. Both can be measured. Then, by rotating the circular workpiece by the rotary table, the positional deviation of the circular workpiece in the radial direction of the rotary table is detected at the same location in the circumferential direction of the circular workpiece at a plurality of positions in the circumferential direction of the circular workpiece. Furthermore, it is possible to easily detect the deviation of the feature point position on the surface of the circular workpiece from the center position of the straight line.

  The reference numerals in the parentheses indicate the correspondence with specific means described in the embodiments described later.

  As described above, according to the method for measuring a diameter of a circular workpiece of the present invention, it is possible to avoid a decrease in measurement accuracy due to vibration without turning the detection unit, and the position of the circular workpiece is deviated from a predetermined position. In addition, the inner diameter and / or outer diameter of the circular workpiece can be measured with high accuracy.

It is a vertical sectional view of a circular work at the time of position shift detection showing one embodiment of the present invention. It is a top view of the circular workpiece | work explaining the workpiece center position determination method which shows one Embodiment of this invention. It is a top view of the circular workpiece | work explaining the workpiece center position determination method which shows one Embodiment of this invention. It is a vertical sectional view of a circular work at the time of measuring inner and outer diameters showing one embodiment of the present invention.

  The embodiment described below is merely an example, and various design improvements made by those skilled in the art without departing from the gist of the present invention are also included in the scope of the present invention.

  In FIG. 1, a ring-shaped circular workpiece W having the same cross section is placed on a rotary table 1, and a two-dimensional laser displacement sensor 2 is disposed at an upper position of the rotary table 1 downward. The displacement sensor 2 scans the laser beam L on a straight line having a fixed length l and detects the displacement (height in this embodiment) of each point on the straight line based on the principle of triangulation. In the present embodiment, a fixed length l in the radial direction of the rotary table 1 is provided by a single laser displacement sensor 2 provided at a fixed distance from the rotation axis Ax of the rotary table 1 at an upper position facing the peripheral surface of the table. The height of each point on the upper surface of the circular workpiece W is detected on a straight line.

  And in this embodiment, the position shift of the circular workpiece | work W is detected by the highest point Wp on the upper surface of the circular workpiece | work 1 as a feature point. That is, when the highest point Wp is positioned on the vertical line As passing through the scanning center position of the laser displacement sensor 2, the positional deviation amount E = 0, and when the highest point Wp is positioned on the outer diameter side of the vertical line As. The amount of positive deviation is the negative deviation when it is located on the inner diameter side. The measurement of the deviation amount E is performed at four points which are symmetrical positions in the radial direction perpendicular to each other as shown in FIG. 2 by rotating the rotary table 1.

FIG. 2 shows a case where the center O of the circular workpiece W and the rotation axis Ax of the rotary table 1 coincide with each other. The rotary table 1 is rotated to turn the circular workpiece W, and any one of the four circumferential directions is rotated. Even if the positional deviation is measured at points, these deviation amounts E1, E2, E3, and E4 are the same value. Therefore, when the center position O of the circular workpiece W is obtained by the following expression (1), the X coordinate and Y coordinate thereof are 0, and the center O of the circular workpiece W coincides with the rotation axis Ax of the rotary table 1.
X = (E1-E2) / 2 (1)
Y = (E3-E4) / 2

  Since the circular workpiece W is conveyed onto the rotary table 1 by a robot arm or the like, the center O of the circular workpiece W is usually deviated from the rotation axis Ax of the rotary table 1 as shown in FIG. Also in this case, if the rotary table 1 is rotated to turn the circular workpiece W and the deviations E1, E2, E3, E4 of the positions of the perpendicular line As and the highest point Wp are measured at four points in the circumferential direction, From the above equation, the X coordinate and Y coordinate of the center position O of the circular workpiece W can be obtained. In addition, it is good also as a structure which provides the laser displacement sensor 2 in four places, without providing the rotary table 1. FIG.

  After the position of the center O of the circular workpiece W is determined in this way, the position of the center Os of the linear scale 31 constituting the diameter measuring device 3 is set to the center O of the circular workpiece W as shown in FIG. Move to match. It is not necessary to make the position of the center Os exactly coincide with the center O in the radial direction to be measured. The linear scale 31 is provided with a pair of sliders 32 and 33 so as to be movable along the sliders 32 and 33. The sliders 32 and 33 have a laser displacement in which the inner side along the linear scale 31 is the measurement region Z1 at the lower end. A total of 34 and 35, and laser displacement meters 36 and 37 having a measurement area Z2 on the outer side are provided at the vertical positions, respectively.

  Therefore, when measuring the outer diameter of the circular workpiece W, the laser displacement meters 34, 35 are positioned toward the outer periphery of the circular workpiece W as shown in FIG. The sliders 32 and 33 are moved to the measurement area Z1. Since the movement positions of the sliders 32 and 33 are detected by the linear scale 31, the radial straight line passing through the center O of the circular workpiece W by a known method from the total length of the known linear scale 31, the slide amount, and the measured displacement value. The distance between the outer peripheral surfaces above, that is, the outer diameter D1 of the circular workpiece W can be calculated and measured.

  When measuring the inner diameter of the circular workpiece W, the laser displacement meters 36 and 37 are positioned toward the inner periphery of the circular workpiece W as shown in FIG. The sliders 32 and 33 are moved to Z2. Since the movement positions of the sliders 32 and 33 are detected by the linear scale 31, the movement of the sliders 32 and 33 on the straight line passing through the center O of the circular workpiece W by a known method from the total length of the known linear scale 31, the slide amount, and the displacement measurement value. The distance between the inner peripheral surfaces, that is, the inner diameter of the circular workpiece W can be calculated and measured. Note that, in the above procedure, a portion requiring calculation is executed by a calculator such as a computer (not shown).

  In the above embodiment, the displacement measurement is not limited to the non-contact type using a laser or the like, and may be performed by a contact type such as a touch probe. Further, if the inner and outer diameters are measured in advance for the calibration work having a known inner and outer diameter by the above procedure, an accurate absolute value can be obtained in the subsequent measurement of the inner and outer diameters of the circular work.

  It is possible to measure the thickness of the circular workpiece by providing the laser displacement meter of the above diameter measuring device in the vertical position so that the circular workpiece is sandwiched, and detecting the highest points on the upper and lower workpiece surfaces. As part of the measurement, the above-described position detection of the circular workpiece based on the highest point on the upper surface may be detected. It is not always necessary to detect the deviation amount based on the highest point on the surface of the circular workpiece, and a feature point that is another mark may be used. Further, the circular workpiece is not limited to a ring shape.

DESCRIPTION OF SYMBOLS 1 ... Rotary table, 2 ... Two-dimensional laser displacement sensor (two-dimensional displacement sensor), 3 ... Diameter measuring device, As ... Center position, Ax ... Rotating shaft, D1 ... Inner diameter, D2 ... Outer diameter, E, E1, E2, E3, E4 ... misalignment, O ... center, W ... circular workpiece, Wp ... highest point (feature point).

Claims (1)

A step of detecting a positional deviation of the circular workpiece in a direction that linearly crosses the circumferential surface at a plurality of circumferential positions of the circular workpiece, and a center position of the circular workpiece is determined based on the detected deviation amount of the positional deviation. And measuring at least one of an inner diameter and an outer diameter of the circular workpiece on a straight line passing through the determined center position , and rotating the rotary table by placing the circular workpiece on the rotary table. By rotating around the axis, misalignment of the circular workpiece in the radial direction of the rotary table is detected at a plurality of positions in the circumferential direction of the circular workpiece, and one circumferential direction around the rotary axis of the rotary table is detected. A two-dimensional displacement sensor that detects the displacement of each point on a straight line of a certain length in the radial direction of the rotary table is disposed at a location, and the feature point position on the surface of the circular workpiece is Diameter measuring method of a circular workpiece for the deviation from the central position of the line and the position deviation of the radial direction.

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