SU932200A1 - Device for determination of normal stresses in interference fit connections - Google Patents

Description

(, 5) GVO DEVICE FOR DETERMINING NORMAL STRESSES IN TENSION COMPOUNDS

one

The invention relates to testing equipment and coins to be used to study the contact stiffness of loaded compounds with tension.

A device for measuring the strain at the point of contact of two specimens during removal is known. The device is made in the form of a tube attached in the upper part of the central channel of one test specimen. The tube bears a traverse with a scale and serves as a pusher for the pusher, resist, into the abutting surface of the upper specimen and connected with the lever fl.

A disadvantage of this device is that it allows the determination of normal stresses only in flat specimens.

The closest to the proposed technical essence and the achieved result is a device for detecting normal stresses in a tensioned connection, which contains a conical wipe {stub and sleeve, conjugated to each other, support for the sleeve and an axial displacement sensor of the rod. In this device, an axial load is applied to the rod and the sleeve mounted on the support, and the axial displacements of the rod are measured using a sensor, and the normal stresses in connections with tension G2 are determined from known ratios.

The disadvantage of this device is the low accuracy of the determination of normal stresses in connections with tension. This is due to the fact that in the area of preliminary displacement between tangential and normal displacements to the interface of the contacting bodies there is no linear dependence.

Claims (2)

In addition, errors may arise from additional volumetric deformations of the sleeve and the support. 3 Accuracy is also reduced because with a known fixing of the sensor of axial displacements, its deformations will be affected by deformations at the place of contact of the sleeve and the support. Thus, the normal stresses in the joints with the tension using a known device will be fashionably determined with errors depending on the strength of the force applied to the rod. The purpose of the invention is to improve the accuracy of measurements. This goal is achieved by the fact that the device for determining normal stresses in joints with a tension is supplied with a sensor normal displacements of the sleeve and a comparator unit, connected by a membrane with these sensors, the sleeve is made with a blind hole, the axis of which is perpendicular to the conical surfaces and with the bottom of which contacts the probe of the normal displacement sensor, and the axial displacement sensor is attached to the hub. The drawing shows the device described. The device comprises a tapered rod 1 and a sleeve 2, conjugated to each other, a support 3 for the sleeve 2 and a sensor i axial shifts Oster, sensor 5 normal movements of the sleeve 2 and block 6 comparison. The sleeve 2 is made with a blind hole 7, the probe 8 of the sensor 5 is in contact with the bottom of the blind hole 7 and the sensor k axial displacement 1 is fixed on the sleeve 2 by a collar 9. The device operates as follows. Under the action of the axial force P, the surfaces of the rod 1 and the bushings 2 undergo micro-movements. Axial and normal displacements, judging normal stresses, are recorded by means of sensors k and 5, the signals from which are sent to comparison unit 6, as a result of which the dependence is indicated by 4 displacements. In the process of loading, the sleeve 2 and the support 3 are deformed in the volume and the contact between them. However, these deformations do not affect the measured values of the microdisplacements of the surfaces, since the sensor k of the axial displacements of the gauges 1 is fixed relative to the Sleeve 2, and the measuring probe 8 of the sensor 5 is directed perpendicular to the applied force. The proposed device makes it possible to more correctly investigate the influence of the microgeometric features of the contacting surfaces on the performance characteristics of products that use compounds with strain, to ensure their high reliability and durability, and to speed up laboratory research. Apparatus of the Invention A device for determining normal stresses in connections with a tension, comprising a conical rod and sleeve, connected to a mend, a support for the sleeve and an axial displacement sensor of the rod, characterized in that it has CHaf) a sensor of normal displacements of the sleeve and a comparison unit connected between these sensors, the sleeve is made with a blind hole, the axis of which is perpendicular to the conical surfaces and with the bottom of which the probe of the normal displacement sensor contacts And axial displacement sensor rod secured to the sleeve. Sources of information taken into account in the examination 1. The author's certificate of the USSR N 122923, cl. G, 195U. 2. USSR author's certificate N 130225, cl. G 01 H 3/18, I960 prototype).