SU1532799A1 - Method of measuring mean diameter of internal thread - Google Patents

Abstract

The invention relates to mechanical engineering, in particular to methods and means of controlling threads. The purpose of the invention is to improve accuracy by reducing the effect on the result of monitoring the deviation of the thread pitch and expanding the information content by making it possible to measure the deviation from the coaxiality of the average and internal thread diameters. This is achieved by using one of the inserts of rectangular cross section with the working face in the form of a continuous cylindrical surface and placing it on the tops of the thread along the inner diameter. Measurements are made in at least three sections uniformly circumferentially distributed and determine half of the maximum difference of these measurements. 1 hp ff, 2 ill.

Description

The invention relates to mechanical engineering, in particular to methods and means of controlling threads.

The purpose of the invention is to improve accuracy by reducing the effect on the result of monitoring the deviation of the thread pitch and expanding the information content by making it possible to measure the deviation from the coaxiality of the average and internal thread diameters.

FIG. 1 shows an example of execution of threaded inserts attached to the tips of the measuring device and their placement in the thread; in fig. 2 shows section A-A in FIG. one.

A method for measuring the average diameter of an internal thread is that a tapered insert 1 with a flat end is placed in the cavity of the measured thread with a half-pitch diameter with a taper angle (B, smaller angle about the trough profile, a second insert 2 of rectangular cross section a face on a cylindrical surface whose diameter is less than the nominal value of the inner diameter of the measured thread with a length of at least two thread pitch is placed diametrically opposite to the tapered insert 1 and base it on the tops of the threads Internal diameter s.Inserts 1 and 2 are fixed respectively on measuring tips 3 and 4 and adjusted to a controlled size by gauge or other known methods, then placed in the measured thread of part 5. The block size of gauge lengths for adjustment to controlled size is determined by the formula

ate

with

No

WITH

with

Pep + DBH 2

where D is the nominal size of the average diameter;

UfcH is the actual size of the inner diameter. In each section of the thread, two measurements are carried out, the second measurement being carried out after turning the measuring inserts through 180 °, and the value of the average diameter is determined as a result of the addition of the adjusted size and the indicator reading by the formula

 2A-0bH +

W + PG +

+ P

where P is the indicator reading; i is the number of measurements.

The deviation from the coaxiality of the inner diameter relative to the average diameter of the inner thread 20 is determined as half the maximum difference of the indicator reading.

Claims (2)

1. A method for measuring the average diameter of an internal thread, which consists in placing in a thread Q five 0 50 35 diametrically opposite one another, two threaded inserts tuned to the size of the monitored thread parameter use one of the truncated cone inserts with a working face in the form of a smaller cone base, and the average diameter of the internal thread is determined by the deviation of the position of the inserts from the adjusting position, that, in order to improve accuracy by reducing the effect on the control result of the deviation of the thread pitch, a second rectangular section insert is used, the working line of which is about A striking cylindrical surface with a diameter less than the nominal value of the inner diameter of the monitored thread and an extent of at least two thread steps is placed on the tops of the thread along the inner diameter. t. 2. A method according to claim 1, characterized in that, in order to expand the information content by providing — the possibility of measuring the deviation from the coaxiality of the inner diameter relative to the average diameter of the inner thread, measurements are made in at least three evenly spaced circumferentially inner diameters , and determine the deviation from alignment by half the maximum difference between measurements. Phases. 2