JPS6227607A - Method for measuring accuracy of thread - Google Patents

Abstract

PURPOSE:To measure the pitch, diameter and taper of a thread accurately, by changing the relative position between a displacement sensor and a work in one direction along a profile copying board, and measuring the height of each thread of the work by the sensor. CONSTITUTION:A work 1 is an artificial graphite electrode. A displacement sensor 2 is provided so that it can be moved along a copying board 3. With the sensor 2 being moved in the direction 8 at a constant speed, the height of the screw thread of the electrode is continuously measured. The measured value is amplified by an amplifier 4 and displayed on a display device 7 through an A/D converter 5 and operator 6. Namely, the height of the screw thread is detected by the sensor 2, and the analog signal undergoes digital processing 5 and operating processing 6. Thus the accuracy is measured. At this time, the distance between the screw thread is measured by the sensor 2 by utilizing light. Based on this value, the height is obtained. The light is outputted from the sensor 2, which is moving in the direction of an arrow G at a constant speed. The light reaches the surface of the thread of the work 1 through a light path 9 and returns to the sensor 2 through a light path 9'. Based on the amount of light, distance between the sensor 2 and the surface of the work 1 is measured. Therefore, labor in the inspecting processes is saved and reliability can be improved by the 100% inspection.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is directed to the accuracy of threads, that is, the pitch of machined threads,
Concerning a method for accurately and continuously measuring thread diameter, thread taper, etc. within a short period of time, it is particularly suitable for precisely measuring all large diameter threads such as artificial graphite TIL polar joints, and is also suitable for automatic measurement. The present invention also relates to a method for measuring f# of screws, which can be easily carried out.

(Prior art) The method normally used to measure the accuracy of screws is to insert a link gauge, plug gauge, etc. into the screw and read the difference from the reference value using a dial gauge.
has been standardized.

For example, the method for inspecting the thread accuracy of artificial graphite electrode joints is standardized in JIS R-202.

These conventional methods require inspectors to manually gauge the screws.
It takes a long time to test all the screws, so a sampling inspection method is actually used.

(Problem that @Akira should solve 5) However, in actual operation, there are many cases in which sampling measurements are unsatisfactory, and the precision of all screws must be measured.
: There is a strong demand for the development of an easy and quick measuring method and a demarcation device.

(Means for Solving the Problems) In order to meet the above requirements, the present inventors have conducted extensive research, and in recent years displacement sensors for each building have been developed.Using these displacement sensors, it is possible to It is possible to accurately measure the height of all threads (finding the coordinates of the top of the thread on a chart), and if you calculate based on this measurement value, you can determine the purpose. The present invention was completed based on the knowledge that the displacement sensor and the workpiece having a screw can be changed in one direction along a profiling board. This invention relates to a method for measuring the ellipse of a screw characterized by measuring the simplicity of each screw thread of a workpiece and determining the screw pitch, screw diameter, and screw taper from the measured values.

Next, the method of the present invention will be explained based on an example of one way to implement invention #14 shown in FIG.

In the figure, / is a workpiece, an artificial graphite electrode, and λ is a displacement sensor. The displacement sensor a is movable on the profiling board 3.

(The displacement sensor 3 may be fixed and the workpiece 1'M moved.) While the displacement sensor 3 is moved at a constant speed, the height of the thread of the electrode is continuously measured.

The measured value is amplified by an amplifier and displayed on an analog scanning chart, for example as shown in the examples below, and
/D converter! , is shown on the display via the computer 6. In other words, the height of the screw thread is detected by a displacement sensor, the analog signal is digitally processed, and the accuracy is measured by arithmetic processing.◇The direction of the farting board should match the reference angle of the taper of the screw. .

Figures ag2 and 6 are schematic diagrams illustrating a method that uses the principal as a displacement sensor, determines the distance t-11 between the sensor and the thread, and calculates the height of the thread from the measured value. . The light emitted from the displacement sensor 3 moving at a constant speed in the direction t is delayed to the thread surface of the work l by the optical path te, and returns to the sensor by t'. The distance between the sensor and the workpiece surface is measured by the light weight.

Contact type (differential transformer type) is used as a displacement sensor.
, any non-contact method (visible light, laser, light beam) is possible.

The method of the present invention is effective for measuring all threads. However, it can be particularly effectively applied to two-pieces and sockets made of artificial graphite electrodes, which have been considered difficult to use as sensors due to their porous surfaces. 2. Measurements are taken not only on one line of the thread plane, but also on the opposite IIl! lS can also be measured on several lines.

(Function) Continuously change the relative position between the sensor and the workpiece, measure the thread thickness t of the workpiece, and plot the position +t' of the top of the metal screw field on the workpiece as a coordinate on the chart. can. By digitizing these coordinates, the thread pitch, taper, and thread diameter can be determined by calculation.

(Example) Using the apparatus shown in Figures 1, 2, and 6, an optical displacement sensor (non-contact type) was used, an artificial graphite screw thread test piece was used as the workpiece, and the workpiece was fixed on a table. and slid the table at a constant speed.

Example 1.2 Scanning charts of graphite screws in the process of implementing the method of the present invention are shown in FIG. 4 (Example 1) and FIG. 5 (Example 2). Each peak on the chart represents the top of the thread, and the value listed for each peak indicates the height of the top of the thread.

Note that since the distance that can be measured with this method is extremely short, the top of each peak indicates the correct crest of the thread, but the valley does not indicate the actual valley, but rather indicates the detection limit of the signal.

Next, the thread pitch and thread taper were calculated from the valley peak locus #(z, y) in each figure according to the missing formula.

n-1 Thread pitch 5. Σ("j+t-c) $11111 Thread taper n coordinate points, i.e. ($1 + 71
) *(W, #y, )..., (zl・h) Gradient of the single @ return formula The result In Example 1, pitch wm 8.46w Taper 厘±0'Example 2
The graphite screw used in Example 1.2 was measured using a conventional manual method, ie, using a pitch gauge and a ring gauge.

As a result, the pitch of the screw of Example 1 was 8.46ta and the taper was 0', and the pitch of the screw of Example 2 was 8.46mm.
, the taper was 18'. This measurement requires 5
It took 5 minutes and 5 molecules t. The above results are consistent with the results obtained by the method of the present invention.

Example 6 The thread pitch was repeatedly measured by the method of the present invention using an artificial graphite Ic 1000 socket and a Nigu Ny as test pieces, and the results are shown in Table 111g1.

Example 4 Thread taper was repeatedly measured according to the present invention using an artificial graphite electrode socket as a test piece. The results are shown in Table 2.

Table 2 (Effects of the Invention) According to the method of the present invention, it is extremely easy to measure the accuracy of all screws, and it is possible to perform a complete inspection by online automatic -j determination. Shikatsu [It has the effect of saving labor in the thread accuracy inspection process, improving reliability through 100% inspection, detecting defective products early, and reducing the defective rate through feedback to the thread processing process, and improving the quality of threaded products by ¥1. It is also easier to use, cost reduction is realized, and it is extremely useful.

[Brief explanation of drawings]

FIG. 1 shows one example of the final steps for carrying out the present method. 2 and 3 are schematic diagrams of a device for carrying out the present invention using light as a displacement sensor, and FIG. 2 is a side view;
FIG. 6 is a front view. 4 and 5 are scanning charts showing the height of the graphite screw in Example 1.2. In the figure, l is a workpiece, C is a displacement sensor, J is a tracing board, 6 is a calculator, and 7 is a display.

Claims (1)

[Claims] While changing the relative position of the displacement sensor and the workpiece with a screw in one direction along the profiling board, the displacement sensor measures the height of each thread of the workpiece, and from the measured values, the screw pitch, screw diameter, A method for measuring the accuracy of a thread, characterized by determining the thread taper.