SU1262390A1 - Piezoelectric accelerometer with moving-coil calibration device - Google Patents

Abstract

The invention relates to a measurement technique, specifically to devices for measuring parameters of vibration and shock with remote performance verification. The purpose of the invention is to increase the coeffin conversion rate during calibration. The magnetic system of the device consists of 11 permanent magnets 10 arranged around the circumference of the magnetically conductive hinge and in the gaps between which there is a part of the inertial element 6.. A magnetically conducting ring 12 with a winding 13 fixed on the inertial element 6 makes it possible to eliminate the non-working tangential components of the magnetic flux. Under the action of the measured acceleration with on the electrodes of the piezoelectric element 4, there arises (it is proportional to the electric charge due to the axisymmetric bending of the plate 2 and the piezoelectric element. Manufacturing permanent magnets from supercritical hard magnetic material results in a higher value of magnetic induction in the gap. 1 C. ad hoc, 2 il. i..V

Description

The invention relates to measuring equipment, and more particularly to a device for measuring vibration and shock parameters with remote performance monitoring. 5

The purpose of the invention is to increase the conversion coefficient of the accelerometer during calibration.

Figure 1 shows the accelerometer, a section along its axis of sensitivity} figure 2 - section aa in figure 1.

The accelerometer contains a magnetically conductive housing 1, an elastic plate 2 with a rod 3, a piezoelectric element 4, mounted on the plate 2, for example, with glue, and an inertial ring element, consisting for convenience of assembly of three parts 5-7 connected by themselves, for example, by screws 8. The electrodes of the piezoelectric element are electrically connected to the terminals 9. Permanent magnets 10 are included in the magnetic system of the calibration device, which are mounted, for example, on glue around the circumference of the magnetically conducting yoke 11, and part of the inertial element 6 is partially found In the gaps between the permanent magnets 10, the magnetically conducting ring 12 mounted on the part 6 of the inertial element and the lower part of the housing 1. In this case, the yoke 11 with the magnets 10 is located in the annular space between the inertial element and the rod 3, The winding 13 is wound on the magnetically conducting ring 12 and together with it is placed in the working gap of the magnetic circuit between the magnets of the 10th case 1. The beginning and end of the winding are electrically connected to the terminals 14.

The device operates as follows.

When a measured acceleration acts along the axis of symmetry of the accelerometer, a displacement of the inertial element relative to the housing 1 and axisymmetric bending of the plate 2 and the piezoelectric element 4 occur. A charge proportional to the value of the effective acceleration arises on the electrodes of the piezoelectric element. The corresponding voltage is removed from the terminals 9. During calibration, the input voltage from the generator is supplied to the terminals 14, as a result of which a current arises in the winding 13, which, according to Ampere's law, causes a force acting on the winding and directed along the axis of symmetry of the accelerometer. Under the action of this force, the inertial element is displaced along the axis, the piezoelectric element 4 is bent, and a voltage proportional to the current flowing through the winding 13 is removed from the terminals 9.

The proposed device, in comparison with the known one, allows to obtain a more optimal combination of the parameters of the measuring and calibration U channels of the piezoelectric accelerometer, such as eliminating the need for magnetic flux through an elastic plate and an inertial element, it is possible to increase the sensitivity and accuracy of the device through the use of more suitable materials and the use of articulating the inertia element on the plate.

The transfer of permanent magnets into the annular space between the inertial element and the central rod and the partial introduction of the inertial element into the gaps between the permanent magnets can reduce! accelerometer dimensions.

In addition, the transmission coefficient is increased during calibration both by obtaining a higher value of 30 magnetic induction in the gap (the manufacture of permanent magnets from supercritical magnetically hard material, a decrease in the magnetic resistance of the magnetic circuit elements), and in 25 communication with the use of a magnetic circuit to eliminate non-working tangential components of magnetic flux. While maintaining the sensitivity and dimensions of the known device, the indicated measures can equivalently increase the transmission coefficient during calibration.

The proposed design of the calibration device of the piezo-accelerometer 45 most fully (of the known types of calibration devices) meets the specified criteria and has a sufficiently high transmission coefficient during calibration, which provides an effective verification of the parameters of the accelerometer ee and obtaining a good signal-to-noise ratio even at low levels of the input test signal.

Claims (2)

1 The invention relates to measurement technology, and more specifically to devices for measuring vibration and shock parameters with remote testing of performance. The purpose of the invention is to increase the conversion rate of the accelerometer during calibration. Figure 1 shows the accelerometer, a section along its axis of sensitivity} in figure 2 - section aa in figure 1. The accelerometer contains a magnetically conductive body 1, an elastic plate 2 with a rod 3, a piezoelectric element 4 mounted on the plate 2, for example, with glue, and an inertia ring element, for convenience of assembling from three parts 5-7, interconnected with each other, for example , screws 8. The electrodes of the piezoelectric element are electrically connected to the terminals 9. The magnet system of the calibration device consists of permanent magnets 10, which are installed, for example, on the glue around the circumference of the sprag 11 magnetic circuit, and part of the inertial element 6 It is located in the gaps between the permanent magnets 10, the magnetic conductive ring 12 mounted on the part 6 of the inertial element, and the lower part of the housing 1, and the PM 11 with the magnets 10 is located in the annular space between the inertial element and the rod 3, the winding 13 is wound on the magnetic conductor ring 12 and with it placed in the working gap of the magnetic circuit between the magnets 10 and the housing 1, the beginning and end of the winding are electrically connected to the terminals 14. The device operates as follows. When acting along the axis of symmetry of the accelerometer of the measured acceleration, an inertial element is displaced relative to the housing 1 and the axisymmetric bending of the plate 2 and the piezoelectric element 4. On the electrodes of the piezoelectric element, a charge occurs proportional to the magnitude of the current acceleration. The corresponding voltage is removed from pins 9. During calibration, the input voltage from the generator is applied to pins 14, as a result of which a current arises in coil 13, which causes a force on the coil and is directed along the x-axis accelerometer along Ampée's law. Under the action of this 0 2 s, the inII element of the element is displaced along the axis, the piezoeleite 4 bends from the terminals 9 and the voltage is removed, which is proportional to the current flowing through the winding 13. The proposed device, in comparison with the known, allows to obtain a more optimal combination of the parameters of the measuring and calibration channels of the piezoelectric accelerometer, as well as eliminating the need to conduct a magnetic flux through an elastic plate and an inertial element improves the sensitivity and accuracy of the device by using more suitable materials and the use of hinged inertia element on the plate. The transfer of permanent magnets into the annular space between:, with an inichdona element and a central rod and the partial introduction of the inertia element into the gaps of the mechanics with permanent magnets will reduce the dimensions of the accelerometer. In addition, the transmission coefficient during calibration is due to both obtaining a higher value of magnetic induction in the gap (making permanent magnets from a supercritical hard magnetic material, reducing the magnetic resistance of the elements of the magnetic circuit), and in connection with the use of a magnetic conductive ring to eliminate non-working tangential magnetic flux components. While maintaining the sensitivity and dimensions of the known device, these measures allow an equivalent increase in the transmission coefficient during calibration. The proposed design of a piezo-accelerometer calibration device most fully (of the known types of calibration devices) meets the specified criteria and has a sufficiently high transmission coefficient during calibration, which ensures an effective verification of accelerometer parameters and obtaining a good signal-tcryjvi ratio even at low levels of the input test signal . Claim 1. Piezoelectric accelerometer with magnetoelectric calibration a device containing a circular elastic plate with a central support rod installed in the magnetic body, a piezo element secured to the plate, an inertial ring element mounted around the plate’s periphery, a permanent magnet ring magnetic core and winding a calibration device distinguished by the fact that In order to increase the conversion coefficient when calibrating, a magnetic conductive ring is inserted into it, as well as additional permanent magnets attached to the main magnet through nye intervals on the yoke, which, on its turn, is mounted on a support the rod under the elastic plate, on the magnetic conductor ring, mounted on the inertial element of the coaxial ring, is placed the winding of the calibration device, the inertial element and the elastic plate are made of non-magnetic material, the magnets have a consistent and radial polarity direction, and a part of the ring (center and inertial) element is located in the gaps between the permanent magnets and the housing. 2. The accelerometer according to claim 1, characterized in that the permanent magnets are made of supercritical hard magnetic material.