RU1775630C - Method and device for dynamically graduating dynamometer - Google Patents

Abstract

SUMMARY OF THE INVENTION 1 The harmonic force with which a dynamometer is loaded is created by exciting harmonic movements of a permanent magnet, maintaining their amplitude constant in a predetermined range of oscillation frequencies. At the same time, the dynamometer is loaded with constant force. The device comprises a vibration exciter 1 with a generator 11. A displacement sensor 3 is connected to a vibration exciter 1 and through an amplifier 12, with a displacement amplitude indicator 13. The permanent magnet 4 is mounted relative to the end face of the dynamometer shaft with a clearance defined by the formula q KF, where F is the constant force applied to the dynamometer, and the K coefficient is experimentally determined by 3 ill.

Description

phage 1

The invention relates to measuring equipment and is intended for dynamic testing and calibration of dynamometers of variable forces.

A known method for dynamically calibrating a dynamometer is that the dynamometer is loaded with a harmonic force of a variable frequency by a vibrator, the output signal of the dynamometer is measured and compared with the amplitude of the loading harmonic force.

The disadvantage of this method is the lack of efficiency, due to the impossibility of providing calibration under operating conditions with the test object rotating on the dynamometer shaft, as well as the low accuracy of dynamic calibration due to the fact that the dynamometer rigidly connected to the vibrator is loaded not only by disturbing force, but also by force inertia of the portable movement of the vibrator. The dynamometer reading will correspond to the disturbing force only with a weightless vibrator. In addition, the dynamometer is not loaded with constant force,

A device for dynamic calibration is known, comprising a vibration exciter located on the base in the form of an electrodynamic vibrator, rigidly connected to a dynamometer under test, a generator, an amplifier, and a recorder.

The disadvantage of this device is that, being tightly coupled to the dynamometer under test, it distorts the frequency response obtained during calibration in the region of the natural resonant frequencies of the vibrator, underestimates the values of the resonant frequencies, and does not provide the possibility of calibration under operating conditions with the test object rotating on the dynamometer and setting constant power.

The aim of this proposal is to increase the efficiency by providing the possibility of graduation under operating conditions with the test object rotating on the shaft of the dynamometer, as well as an increase in accuracy.

In FIG. 1 shows a diagram of a device for dynamic calibration; in FIG. 2 - frequency response of a dynamometer obtained by known and proposed methods ;, in FIG. 3 - amplitude-frequency spectrum of the dynamometer during rotation of the shaft with the test object.

The device (Fig. 1) contains a vibration exciter 1 with a core 2, a displacement sensor 3, a permanent magnet 4, a dynamometer 5, on the shaft 6 of which a test object 7, a recorder is fixed 8. The dynamometer is fixed in the experimental setup 9 and

its shaft is driven by an electric motor 10. The causative agent is controlled by a generator 11, to which a motion sensor is connected through an amplifier 12 with a pointer

displacement amplitudes 13. The test object is mounted on the dynamometer shaft with a special nut 14.

When rotating the shaft 6 with the test object 7 in the experimental setup 9 in

Dynamometer 5 excites resonant as well as non-resonant vibrations caused by inertial loads, defects in the rolling elements, dynamic impacts on the gear teeth of the gears, in the drive system, etc. On Fig, 3 shows the amplitude-frequency spectrum of the output signal of the dynamometer, excited by the rotation of its shaft with the test object.

The proposed method and device work as follows.

Set the required clearance. The exciter 1 sets harmonic oscillations to the core 2 using the generator 11, on which the permanent magnet 4 is closed. During harmonic movements of the permanent magnet, an alternating magnetic field is excited, which acts on the shaft of dynamometer 6 with the test object 7. The dynamometer shaft also acts nna force. Its value depends on the size of the constantly selected gap between the magnet and the shaft end of the dynamometer, which is previously determined by the formula F K / d, where K is the coefficient, and d is the gap. Simultaneous setting of the variable and constant force increases the accuracy of dynamic calibration, bringing the calibration conditions closer to the actual operating conditions of the experimental setup. The constant force is then verified by the dynamometer. The frequency of the generator 11 and, consequently, the oscillation frequency of the core 2 and the magnet 4 fixed on it are smoothly changed. In this case, the frequency of the input action on the dynamometer shaft changes. Using the sensor 3, a constant amplitude of movement of the magnet 4 is maintained. It is obvious that the amplitude of the variable force excited by the permanent magnet in the dynamometer does not depend on the oscillation frequency, if the amplitude

Claims (1)

1. The method of dynamic calibration dynamometer, in which the dynamometer is loaded with harmonic force of a variable frequency, measure the output the dynamometer signal and compare it with the sample of the loading harmonic force, characterized in that. in order to increase efficiency by enabling calibration under operating conditions with the test object rotating on the dynamometer shaft, as well as to increase accuracy, the dynamometer is additionally loaded with constant force, and harmonic forces of a constant magnet are used as a harmonic force of a variable frequency, the amplitude of which is maintained constant nn in a given range of oscillation frequencies. 2, A device for dynamically calibrating a dynamometer, comprising an exciter located on the base with a generator, a dynamometer, an amplifier and a recorder, characterized in that, in order to increase the efficiency By providing the possibility of calibration under operating conditions with the test object rotating on the dynamometer shaft, as well as increasing accuracy, a motion sensor connected to the vibration exciter, a permanent magnet and a displacement amplitude indicator are introduced into it, while the output of the displacement sensor through the amplifier is connected with a displacement amplitude indicator and with a generator, and a permanent magnet is mounted relative to the end of the dynamometer shaft with a gap determined by the following relationship: , where F is the constant force applied to the dynamometer; K is the coefficient determined experimentally. 80 100 Fat. 2 160 180 200 frequency Hz 220 20b 150 QO,