JPH04203911A - Method and apparatus for measuring surface strain - Google Patents

Abstract

PURPOSE:To eliminate nonuniformity in a measuring error and to improve the precision in measurement by a method wherein a mark attached on the surface of a substance to be measured is transferred onto a material, a pattern on this material is read optically and a surface strain of the substance is measured. CONSTITUTION:After an autoscan stage 2 is moved in the direction of the X axis so that a material 8 is positioned under an optical fiber sensor 13, the stage 2 is moved in the direction of the Y axis. Then a light emitted from the sensor 13 irradiates the material 8 and is reflected only on the part of a line of a lattice pattern 9. Therefore the reflected light is sensed by the sensor 13 and the lattice pattern is read therefrom. Meanwhile, a distance of movement of the stage 2 and the material 8 in the direction of the Y axis is read even for 1/1000mm on the operation unit 12 side from the rotation of a Y-axis pulse motor 4. Therefore a read signal from the sensor 13 and a position signal from the unit 12 are processed by a signal processing device 16 and an interval between lines of the pattern 9 of the material 8 is calculated. By this method, a surface strain of a tire can be measured automatically and quickly.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method and apparatus for measuring surface strain of articles, particularly objects to be measured such as tires.

(Prior art) For example, in the case of high-load pneumatic tires, for the purpose of basic data for future tire development or quality confirmation of current products, etc.
Measuring tire surface distortion.

When measuring this surface strain, after assembling the tire on the wheel and filling it with the specified air pressure, a checkered pattern mark is attached to the tire surface, and a check mark is placed on the surface of the tire to determine whether a load is applied to the contact surface of the tire or when no load is applied. A method is adopted in which the intervals between the grid patterns of the marks are read over time, and the surface strain of the tire, that is, the shear/compressive strain, is measured based on the state of change. To read the intervals of the checkered pattern of marks, a magnifying glass is used at -a to visually inspect the middle pages.

(Problems to be Solved by the Invention) Conventional measurement methods have the disadvantage of poor work efficiency due to visual inspection by workers, and large variations in measurement errors between individuals, resulting in a lack of reliability. be.

In view of the above, the present invention provides a method and apparatus that can easily and quickly read the surface distortion of an object to be measured, such as a tire, with high accuracy.

(Means for solving t!JN) The measuring method according to the present invention transfers marks made on the surface of the object to be measured onto a document 8, optically reads the pattern of this document 8, and measures the surface of the object to be measured. It measures surface strain.

Further, the measuring device according to the present invention is provided with an auto-scan stage 2 on which a document 8 on which marks attached to the surface of the object to be measured are transferred is movable in the X-axis and Y-axis directions, and
An optical fiber sensor 13 for optically reading the pattern of the document 8 is provided above the auto-scanning stage 2, and a signal processing device 16 is provided for processing the signal read by the optical fiber sensor I3.

(Function) When measuring surface strain, the pattern of marks made on the surface of the object to be measured, such as a tire, is transferred to document 8.

Next, after setting this document 8 on the auto scan stage 2, while moving the auto scan stage 2 in a predetermined direction, the pattern of the document 8 is optically read by the optical fiber sensor 13 above it, and the signal processing device 16 The surface strain is measured by signal processing.

Therefore, surface strain can be measured very easily, quickly, and efficiently. Furthermore, since it is automatically read, there is no variation in measurement errors, and highly accurate reading is possible.

(Example) Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

In Figures 1 and 2, 1 is a fixed base, 2 is a fixed base 1
With the auto scan stage installed above,
It is movable in the axial direction, and the X-axis and Y-axis are
It is designed to be driven in the axial direction. A transparent document table 7 is placed on the auto-scan stage 2, and four documents 8, for example, are pasted on this document table 7. Each document 8 is obtained by transferring a checkered pattern 9 of marks made on the surface of a tire onto a transparent tape or the like.

Reference numeral 10 indicates a driver box, and reference numeral 11 indicates a controller box, which constitute an operation unit 2 that gives commands to and controls each of the pulse motors 3 and 4. Reference numeral 13 denotes an optical fiber sensor, which is installed above the auto-scanning stage 2 so as to be able to optically read the grid pattern of each document 8. It is attached to the tip of the extending arm 15. 16 is a signal processing device consisting of a microcomputer, etc., which calculates the spacing between the lines of the grid pattern 9 of document 8 from the signal of the grid pattern 9 read by the optical fiber sensor 13, the position signal of the auto scan stage 2 from the driver box 10, etc. The system also calculates the tire surface strain. Note that the surface strain is calculated using the following formula.

When measuring the surface strain of a tire, after filling the tire with the specified air pressure, take data 8 under load and under no load. This is done by transferring the lattice pattern of marks made on the tire surface onto a transparent tape or the like.

Next, each material 8 is affixed in parallel to a predetermined position on the material table 7, and the four materials 7 are placed on the auto scan stage 2 and set. And document 8 is optical fiber sensor I3
Move the auto scan stage 2 so that it is located below
After moving the auto scan stage 2 in the axial direction,
Move it in the axial direction. Then, the light emitted from the optical fiber sensor 13 illuminates the document 8 and is reflected only at the 90-line portion of the grid pattern, so the reflected light is received by the optical fiber sensor 13 and the grid pattern 9 is read.

On the other hand, since the movement distance of the auto scan stage 2 and the document 8 in the Y-axis direction is read in units of 1/1000 aun by the operation unit 12 by the rotation of the Y-axis pulse motor 4, the reading signal from the optical fiber sensor 13 and the operation The position signal from the unit 12 is processed by the signal processing device 16, and the intervals between the 90 lines of the grid pattern of the document 8 are calculated.

In this way, the same process is performed for each document 8, and appropriate processing (comparing the difference in the spacing of the grid pattern) is performed for each document 8 or between the documents 8 to be compared, to determine the tire size. Automatically measure surface strain. Therefore, since the measurement of surface strain is automatic, the work can be carried out very easily and quickly, and there is no variation in measurement errors, and the measurement accuracy is significantly improved.

In addition, as shown in Figure 1, an optical fiber sensor (13
) By connecting a digital counter to the code, it is possible to automatically count the number of tire finish code ends.

i.e. the reflected light of the fiber optic sensor (from the cord)
can be counted by a digital counter.

Although the example described the surface strain of tires, the object to be measured is not limited to tires, and it goes without saying that the present invention can also be used to measure the surface strain of pressure vessels or objects other than metals. Nor.

(Effects of the Invention) The measuring method according to the present invention transfers the mark on the surface of the object to be measured onto the document 8, and optically reads the pattern of this document 8 to measure the surface distortion of the object to be measured, so it is easy to use. And it can be done quickly.

Further, the measuring device according to the present invention includes an auto scan stage 2 on which a document 8 on which marks on the surface of the object to be measured are transferred is placed.
is provided to be movable in the X-axis and Y-axis directions, and an optical fiber sensor 13 for optically reading the pattern of the material 8 is provided above the auto-scan stage 2, and a signal processing system for processing the signals read by the optical fiber sensor 13 is provided. Since the device 16 is provided, it is possible to measure automatically. Therefore, the measurement can be performed easily and quickly, and there is no variation in measurement error, and the measurement accuracy is improved.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing one embodiment of the present invention, and FIG. 2 is a front view of the same. 2...Auto scan stage, 8...Document, 9.
...Lattice pattern, 13...Optical fiber sensor, 16
...Signal processing device.

Claims (2)

[Claims] (1) Surface distortion characterized by transferring a mark on the surface of the object to be measured onto a document (8) and optically reading the pattern of this document (8) to measure the surface strain of the object to be measured. Measuring method. (2) Materials with transferred marks on the surface of the object to be measured (
An auto-scan stage (2) on which the material (8) is mounted is provided so as to be movable in the X-axis and Y-axis directions, and an optical fiber sensor (13) is installed above the auto-scan stage (2) to optically read the pattern of the material (8). 1. A surface strain measuring device comprising: a signal processing device (16) for processing a signal read by the optical fiber sensor (13).