RU2545310C2 - Non-contact suspension of rotor - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention relates to instrument engineering and can be used in non-contact gyroscopes, accelerometers and magnetic bearings. The proposed non-contact suspension of a rotor comprises pairs of rotor supporting elements installed in diametrical opposition and made as electromagnets or electrodes connected to the outputs of a phase inverter with its input being connected to an AC voltage source, and one common adjusting element in the form of a capacitor or an induction coil used for every pair of supporting elements and connected between the common connection point of the supporting element pair and the common point of the phase inverter.

EFFECT: usage of one common adjusting element allows for the simplification of the proposed suspension design, provides for linearity of traction characteristic and stability of zero rotor position due to the fact that change of values of two adjusting elements as in standard resonance suspension is excluded.

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Description

Technical field

The invention relates to the field of instrumentation and can be used in non-contact gyroscopes, accelerometers and magnetic bearings.

State of the art

The simplest non-contact suspensions of ferromagnetic and conductive rotors are based on the use of resonant LC circuits, which are formed either by inductors of supporting (traction) electromagnets with tuning capacitors (Zhuravlev Yu.N. Active Magnetic Bearings. - St. Petersburg: Polytechnic, 2003, p. . 11-12, Fig. 1-7), or capacitances of supporting capacitors with tuning inductance coils (http: file: ////mexman.ru "Gyroscope with electrostatic suspension", p. 9-10, Fig. 2). In such non-contact rotor suspensions, pairs of diametrically opposed supporting elements are used, each of which is connected to a corresponding tuning element.

Known improved suspension of the rotor, adopted for the prototype, and a description of which is given in the article "Advanced electromagnetic resonance suspension of the body", the journal "Gyroscopy and navigation", 1998, No. 2 (21), pp. 82-87, Fig. 1, and in the patent of the Russian Federation No. 2077175 "Suspension device of a ferromagnetic body." The rotor suspension described in the article "Advanced electromagnetic resonance suspension of the body", the journal "Gyroscopy and navigation", 1998, No. 2 (21), pp. 82-87, Fig. 1, adopted as a prototype of the invention. Such a suspension contains pairs of diametrically opposed supporting elements (electromagnets) connected to the outputs of the phase inverter, the input of which is connected to an AC voltage source. The voltage phase at one of the outputs of the phase inverter is shifted 180 degrees with respect to the voltage phase at the other output. This made it possible to use one damping two-terminal for each pair of LC-circuits of the suspension instead of two with the traditional single-phase power supply of the suspension. Due to the duality of electromagnetic and electrostatic suspensions, this technical solution is also valid for suspending a conductive rotor with supporting elements in the form of electrodes forming containers with the rotor surface. The disadvantage of the prototype is the use for a pair of supporting elements of two tuning elements, which complicates the design of the suspension, the nonlinearity of the traction characteristics of the suspension and the instability of the zero (central) position of the rotor.

SUMMARY OF THE INVENTION

The objective of the invention is to simplify the design of the suspension of the rotor, linearize the traction characteristics and eliminate the instability of the central position of the rotor due to a change in the parameters of the tuning elements. The problem is solved by the very simple inclusion of one common tuning element between the common point of connection of a pair of supporting elements and the common point of the bass reflex.

List of figures and drawings

Figure 1 shows the electrical circuit of the prototype - suspension of the rotor, with supporting elements - electromagnets and tuning elements - capacitors.

Figure 2 is a diagram of the proposed supports with supporting elements - electromagnets and a common tuning element - a capacitor.

Figure 3 shows a diagram of the proposed supports with supporting elements - electrodes and a common tuning element - an inductor.

Figure 4 presents graphs of the traction characteristics of the suspension - the prototype and the proposed suspension.

Figure 1-4 adopted the following notation:

1 - rotor

2 - the first supporting element is an electromagnet,

3 - the second supporting element is an electromagnet,

4 - the first tuning element of the prototype is a capacitor,

5 - the second tuning element of the prototype is a capacitor,

6 - phase inverter,

7 - source of alternating voltage,

8 - damping bipolar,

9 - a common tuning element is a suspension capacitor with electromagnets,

10 - the first supporting element in the form of electrodes,

11 - the second supporting element in the form of electrodes,

12 - a common tuning element is a suspension inductance coil with electrodes.

The proposed non-contact suspension of the rotor contains a pair of supporting elements in the form of electromagnets 2 and 3 (figure 2) or electrodes 10 and 11 (figure 3) connected to the outputs of the phase inverter 6, the input of which is connected to an AC voltage source 7. The common tuning element in the form a capacitor 9 (FIG. 2) or an inductor 12 (FIG. 3) is connected between a common point of connection of a pair of supporting elements and a common point of phase inverter 6.

The work of the proposed suspension is as follows. For the circuit of figure 2 (with supporting elements in the form of electromagnets) when the rotor 1 is displaced from the electromagnet 2 to the electromagnet 3, the inductances of their windings L ₂ and L ₃ (determined mainly by the value of the gap with respect to the surface of the rotor) are changed in accordance with the expressions:

,

,

where L ₀ is the winding inductance at a nominal gap δ ₀ between the electromagnet and the rotor (the central position of the rotor),

Δ = Δ _δ / δ ₀ is the relative displacement of the rotor,

Δ _δ is the displacement of the rotor.

The value of the tuning element - capacitor 9 is set approximately equal to:

where ω is the angular frequency of the voltage source 7.

In this case, the current I ₂ through the electromagnet 2 increases, and the current I ₃ through the electromagnet 3 decreases, which creates a restoring force that returns the rotor 1 to the center of the suspension. By setting the inductances by formulas (2) for various Δ values, it is possible to determine the values of currents I ₂ and I ₃ using a computer model, and then calculate the suspension traction force F by the formula:

.

.

Figure 4 shows the relative traction characteristics of the prototype constructed in this way — curve “a” and the proposed suspension — almost direct “b” (K is the ratio of the forces of the proposed suspension and suspension - the prototype, the value K = 1 corresponds to the same maximum loads of the compared suspensions).

For the suspension circuit of Fig. 3 (with supporting elements in the form of electrodes), the displacement of the rotor 1 from the electrodes 10 to the electrodes 11 leads to a decrease in the capacitance of the electrodes 10 and an increase in the capacitance of the electrodes 11. The inductance of the tuning element - coil 12 is set approximately equal to:

,

,

where C ₀ is the capacity of the electrodes 10 (or 11) relative to the surface of the rotor 1 with its central position. When conditions (4) are fulfilled, the suspension has properties similar to the dual circuit (Fig. 2) with electromagnets.

In the proposed suspension, if necessary, damping of the oscillations of the rotor (for example, in a vacuum) are used, as in the prototype, damping bipolar 8 (figure 2 and 3).

The use of one common (for a pair of supporting elements) tuning element allows us to simplify the scheme of the proposed suspension, ensure linear traction characteristics and stability of the zero (central) position of the rotor, due to the exclusion of the relative change in the values of the two tuning elements of the suspension - the prototype.

Claims (1)

Non-contact rotor suspension containing pairs of diametrically oppositely located rotor-supporting elements in the form of electromagnets or electrodes connected to the outputs of a phase inverter, the input of which is connected to an AC voltage source, characterized in that for each pair of supporting elements one common tuning element is applied in the form of a capacitor or coil inductance connected between the common point of the pair of supporting elements and the common point of the bass reflex.

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