RU1772596C - Device for measuring angular displacement - Google Patents

Abstract

The invention relates to a measurement technique. The purpose of the invention is to increase the accuracy of measurements by reducing the inertial component of the sensor oscillations. The device for measuring angular deformations contains two coaxially arranged rings, a sensing element connected to the rings. The rings are made in the form of split collet clamps, and the sensitive element is made in the form of a flat split ring-shaped spring, one end of which is fixed on one of the rings and the other on the other ring, and the gap between the ends of the spring in the unstressed state corresponds to condition 1. 5 p. and 0.0262 R p, where (f is the central angle formed by the ends of the springs, p is the angle of maximum permissible twisting of the device, a is the clearance, R is the radius of the spring ring in the free state. On the inner surface of the ring-shaped spring, it is diametrically opposite to the section the flat C-shaped spring is convex inward, and inside the collet clamps interchangeable annular inserts with cuts are inserted with fixation. 2 EP f-crystals, 3 ill.

Description

The invention relates to measuring technique, and in particular, to devices for measuring angular deformations of cylindrical specimens with an external annular crack under dynamic cyclic torsion.

A strain gauge for measuring longitudinal and angular strains is known, comprising two rings with spring-loaded bearings for mounting on a specimen, two strain gauges associated with the rings, two spherical joints and two parallel rods.

The disadvantage of the strain gauge is the design complexity and low measurement accuracy.

The most simple technical solution is a device for measuring angular deformations, containing two coaxially arranged rings intended for installation on a sample, and a sensing element connected to the rings.

The disadvantage of the prototype is the low accuracy of the measurements.

The aim of the invention is to improve the accuracy of measurement.

This goal is achieved by the fact that in the device for measuring angular deformations, containing two coaxially arranged rings for installation on the sample, and connected to the rings of the sensing element, the rings

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made in the form of split collet clamps, the sensitive element is made in the form of a split ring-shaped spring with a strain gauge placed on it, one end of which is mounted on the first ring, the second on the second ring, the width of the gap between the ends of the spring is not less than 0.0262R p. where R is the inner radius of the ring, the angle is the maximum allowable twisting of the device, and the device is equipped with a flat C-shaped spring mounted on the inner surface of the split annular spring is diametrically opposite to the section with a bulge inward, and interchangeable ring inserts located inside the split collet clamps with the possibility of fixing and made with cuts, the number and dimensions of which coincide with the number and size of cuts of the corresponding collet clamps.

On Fig, 1 shows a General view of the device; in FIG. 2 - top view; in FIG. 3 - section of the sensor with installed removable inserts.

The device for measuring angular deformations consists of a split flat ring-shaped spring 1 with strain gauges 2 attached to it. The ends of the spring 1 are attached to the upper 3 and lower 4 collet clamps, on which rings 5 and 6 are dressed on the thread. On the inner surface of the ring-shaped spring 1 a flat C-shaped spring 7 is fixed diametrically opposite to the section, with a convexity inward, the width of which in the central part is slightly less than the gap between the collet clamps 3 and 4, and the stiffness is less than the stiffness of the spring 1. Inside Angular clamps 3, 4 can be inserted interchangeable liners 8, 9 with cuts, fixed by screws 10. The number and size of cuts correspond to the number and size of cuts of collet clamps 3 and 4.

The gap between the ends of the spring 1 in the free (unloaded) state is determined from the condition

f 1.5 p where a 0.0262 R (p,

where a is the gap;

 - the central angle formed by the ends of the spring;

p is the angle of maximum permissible twisting of the sample;

R is the radius of the spring ring

The device operates as follows,

The device is put on a cylindrical sample with a concentrator and / or with an initial fatigue crack, and a collet clamp 3 is clamped with a ring 5 above the concentrator. Then, twisting the collet clamp 4, select the gap between the ends of the spring 1 and the ring 6 clamp the collet 4 below the hub. This sets the initial deformation of the spring 1.

When torque is applied, the ends of the spring 1 flow rate tc and an electric signal is removed from the load cells 2, which is proportional to the deformation of the annular spring 1.

If necessary, change (reduce) the dimensions of the test sample (within small limits, determined from the strength and rigidity of the collets) to improve the working conditions of the collet clamps and increase the reliability of clamping inside the collet clamps 3, 4, inserts 8, 9 of the required thickness are inserted and fixed with screws 10 so that the sections of the liners 8.9 coincide with the cuts

collet clamps 3, 4. This ensures that the deformation of the petals of the collet clamps and the inserts is consistent when clamped. With a significant discrepancy between the diameters of the sample and collets necessary

replace collet clamps.

The spring 7, abutting the sample in the gap between the collet clamps 3 and 4, keeps the annular spring 1 from vibrations in the transverse direction. Wherein

due to the low stiffness of the spring 7 relative to the stiffness of the spring 1, it does not seriously affect the deformation of the latter. To account for its influence, it is necessary to calibrate the load cells for

different diameters of test samples.

If necessary, rings 5 and 6 can be locked in the clamped position to prevent loosening of the clamps.

from vibration.

Claims (3)

1. A device for measuring angular deformations, comprising two coaxially arranged rings intended to be mounted on the sample and a sensing element connected to the rings, characterized in that, in order to increase the measurement accuracy, the rings are made in the form of split collet clamps, the sensitive element is made in the form of a split annular spring with a strain gauge placed on it, one end of which is mounted on the first ring, the other on the second ring, and the width of the gap between the ends of the spring is not less than 0.0262R p, where R is the inner radius of the ring; (p is the angle of maximum permissible twisting of the device. 2. The device according to p. 1, characterized in that. that it is provided with a flat conformable spring mounted diametrically on the inner surface of the split annular spring opposite to the incision bulge inward. 3. The device according to p. 1, characterized in that. that it is equipped with interchangeable ring inserts located inside split collet clamps with the possibility of fixation and made with cuts, the number and dimensions of which coincide with the number and size of cuts of the corresponding collet clamps. O f ||||| lll.№X  v IS. J / FIG. / put.2 g 4