SU659917A1 - Frequency-output force-measuring transducer - Google Patents

Description

3

In addition, the vibratory crosspieces of the resonator are connected to the unary element and transverse bridges by means of elastic hinges.

FIG. 1 shows a diagram of a converter with a resonator operating, for example, on the second harmonic of oscillations; in fig. 2 shows the construction of a measuring transducer with a frequency output in the case of the operation of its resonator at the first harmonic of oscillations with differences providing a more linear output characteristic; it also shows the connection of the resonator rods with the rest of the structure through elastic hinges.

Measuring frequency converter contains elastic element 1, made with it in one piece resonator 2 and excitation system 3.

The specific form of the elastic element is not directly related to the essence of the invention and is generally represented as a ring.

The resonator 2 contains vibratory jumpers 4 made, for example, in the form of rods having a rectangular cross-section or a triangle-shaped section. Vibration jumpers 4 are located in the plane of oscillation of the resonator 2 coinciding with the plane of the drawing symmetrically with respect to the common longitudinal axis of the resonator X - e: and interconnected by transverse bridges 5 located at equal distances from the ends of the vibratory jumpers perpendicular to the common longitudinal axis of the resonator 2.

The distance from the ends of vibratory shafts 4 to the geometrical axes of transverse bridges 5, perpendicular to the common longitudinal axis of the resonator 2, should be chosen so that the points 6 of intersection of the geometrical axes with the longitudinal axis of the resonator 2 coincide with the antinodes of the vibration modes of the resonator 2.

The excitation system 3 is part of an electromechanical generator with a resonator 2. Here the system is shown consisting, in particular, of a receiver 7 oscillations, an exciter 8 oscillations arranged with a gap relative to the resonator 2 and associated with the input and output of amplifier 9.

In the design of FIG. 2 parts 10 of vibrator heads 4, made in the form of rods, on both sides of the transverse bridges 5 are located at an acute angle with respect to the longitudinal axis X-X of the resonator 2 and form a rhombus.

The crosspiece 5, connecting the vibratory jumpers 4, is made in the form of a spring. The distance between the vibration bars 4 must be chosen from the condition of obtaining the necessary moment of inertia of the cross section of the resonator 2, which, given the

four

the length of the resonator provides the required value of the initial frequency of its oscillations. With values of the critical force of the vibrating straps of the resonator 2 close to zero, the stiffness of the elastic element I should be sufficient to create preliminary tensions in the vibrated straps 4 of the resonator 2, ensuring stable transverse oscillations of the resonator 2.

A resonator with vibratory jumpers with a longitudinal stability margin can operate without its preliminary stretching, as well as by changing the direction of the forces applied to the resonator.

in the latter case, it is advisable to connect the ends of the parts 10 of the vibration jumpers 4 to the elastic element and transverse bridges through elastic hinges 11. The converter works as follows

in a way.

The force P or another measured value, converted to a force, acts on the elastic element 1, which with respect to the force is the first link in the chain

transformations, providing kinematic and (or) power transformations for transmissions to the ends of the resonator 2 calculated forces, L in the required direction. The initial frequency of the resonator 2 at P 0

and the given cavity length is determined by its transverse rigidity, including the additional stiffness introduced in the case of preliminary tensioning of the resonator vibration bars. Oscillations resonator

2 is provided by the excitation system 3. When exposed to pulses P, the longitudinal forces N change the transverse rigidity of the resonator 2 and the associated oscillation frequency. In this part, the operation of the proposed measuring transducer with a frequency output is not fundamentally different from the operation of known similar devices. The features of the construction of FIG. 2 is that the frequency of the resonator is changed not only by changing its transverse rigidity caused by the forces L, but also by changing the moment of inertia of the cross section, which changes under the action of the same force.

Under the action of the tensile force N, the parts 10 of the vibrating jigs 4 are turned in such a way that the angle between them increases. With the value Л, corresponding to 0.7-0.8 Рmax, the angle а approaches 180 °, nonlinearly decreasing the moment of inertia and, accordingly, the frequency of the resonator. This aligns the initial part of its characteristic and it generally becomes more linear. If the force N compresses the resonator, then the moment of inertia increases, further increasing the frequency, which aligns the characteristic closer to its final section.

Improving the stability of the work autohe5

This is not caused by a higher Q of the resonator, due to the fact that the loss of energy through its connection with the elastic element is reduced, since the total bending moment in the vibratory jumpers of the resonator under consideration is less than the corresponding moment of the solid resonator.

The decrease in power required for the buildup of the resonator is caused by the fact that the total mass of the resonator is reduced, between particles of which there is internal friction.

The temperature error of solid resonators is mainly determined by the change in their transverse strength due to a change in the temperature coefficient of the elastic modulus. Due to the fact that the moment of inertia of the vibration jumpers of the resonator under consideration is substantially less than the total moment of inertia of the resonator, a change in their rigidity under the influence of temperature relatively little affects the overall rigidity and, therefore, the temperature error.

The implementation of the resonator of the measuring transducer with a frequency output in the form of at least two vibration jumpers located in the plane of oscillation, connected by transverse bridges between them, makes it possible to significantly improve the metrological qualities of the high-frequency resonator.

Claims (3)

1. Load Converter with frequency output, containing elastic an element made in one piece with it a resonator, an excitation system and measuring the frequency of transverse oscillations, characterized in that, in order to increase accuracy, the resonator is made in the form of at least two vibration vibrating jigs located in the oscillation plane symmetrically relative to the common longitudinal axis of the resonator are interconnected by one or several transverse bridges located at equal distances from the ends of the vibratory jumpers perpendicular to the common longitudinal axis of the resonator. 2. The converter according to claim 1, characterized in that, in order to reduce the linearity of the output characteristic of the converter, the transverse jumper is made in the form of a spring connecting between them are the centers of vibratory jumpers made in the form of rods, for example, of rectangular cross section, with the parts of the crank rod on both sides of the spring located at an acute angle to the longitudinal axis of the resonator, forming a rhombus. 3. Converter on PP. 1 and 2, characterized in that the vibratory jumpers of the resonator are connected to the elastic element and transverse bridges by elastic hinges. Sources of information accepted for vanity during the examination 1. Novitsky V.P. et al. Digital devices with frequency sensors. L., “Energie, 1970. 2 USSR Author's Certificate No. 142462, cl. G OIL 1/10, 1960. l j tnocm „