RU2531029C1 - Brushless two-rotor direct current motor - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: brushless two-rotor direct current motor comprises rotating magnetised deperm rotors with actuating coils and fixed toroid stator with operating winding on it. The actuating coils are fixed at the stator. The rotors are placed by like magnetic poles respectively from the side of inner and outer surfaces of the toroid stator thud forming two cylindrical magnet gaps, inside these gaps there are non-magnet cylinders adjoining the toroid stator and the operating coil of the toroid stator is wound on the above non-magnet cylinders while its turns pass through openings in the toroid stator. The respective half-turns of the operating coil are placed in direct vicinity from cylindrical surfaces of the rotating rotors. The actuating coils of the rotors and the operating coil are connected in series or in parallel to the direct current source. Two independent magnet circuits formed by the rotors and toroid stator are closed through magnetically conductive washers coupled magnetically to the rotors and fixed to magnetically conductive walls of the stator with minimum permitted gaps. Thickness of walls of the non-magnet cylinders is selected so that it is five-ten times bigger than the gap between conductors of the working winding and cylindrical surfaces of the rotors.

EFFECT: increasing energy efficiency, reliability and durability.

3 dwg

Description

The claimed invention relates to the field of magnetism and electrical engineering and can be recommended for use in a wide range of industrial and household products and devices.

DC motors, as a rule, contain electromagnetic stators and rotors with sectioned windings connected to the collector on the axis of rotation, the contacts to the lamellas of which are made of carbon or copper-carbon brushes fixed in opposite brush holders, and the brushes are pressed onto the collector by spring plates.

The disadvantage of such engines is the relatively low reliability of the collector-brush group, associated with the sliding factor of the collector relative to the brushes, that is, with the wear of the brushes and the collector, intensified due to arcing during transitions of contacts from one pair of collector lamellas to another along the rotor rotation. In addition, at the same time one of the sections of the rotor windings is working, which reduces the torque on the motor axis. Arising transients - an exponential increase in the current in the winding section over time, following with a high frequency - up to several kilohertz, reduce the possibility of increasing the rotor speed, which reduces the specific power per unit volume (weight) of the motors and their speed. Such engines are sources of radio interference.

The action of known electric generators and motors is based on the Faraday law on electromagnetic induction, which determines the occurrence of a driving force in a conductor with a current in a transverse magnetic field, or the appearance of induction EMF in such a conductor in the case of a conductor moving in a transverse magnetic field [1-3] .

In electric motors and DC generators, stators based on permanent magnets and DC electromagnets are used, and rotors, the winding of which is sectioned and connected to the collector, to the lamellas of which are connected conductors connected via sliding contacts (usually carbon or copper-carbon brushes) either with a direct current source when the device operates as a motor, or with an electric load when this device operates as a direct current generator (recovery in an electric vehicle x when braking).

Brushless DC motors are known, the rotor of which is a conductive disk located in the transverse magnetic field of a permanent magnet (electromagnet), in which direct current flows from its direct current source in its radial directions. This model was first proposed by M. Faraday in 1821. In this case, sliding contacts are used, associated with the axis of the conductive disk and with its outer edge [4]. Such engines did not find application in power devices due to the large losses in the supply conductors due to the low resistance of the conductive disk. In addition, the presence of sliding contacts reduces the reliability of the operation of such brushless motors.

Another modification of M. Faraday’s electric motor is a brushless motor, the rotor of which is made in the form of a conductive cylinder, a constant current flows through its cylindrical walls, for example, from top to bottom, and the cylindrical walls of this conductive cylinder are placed in a constant transverse magnetic field of a magnet, the magnetic poles of which perform in the form of concentric cylindrical surfaces similar to the magnet of known acoustic speakers [5-6]. It also uses sliding contacts associated with the axis of rotation of the conductive cylinder, bonded to the conductive top cover-base of the conductive cylinder, as well as its lower edge. Such brushless motors also cannot find application in power systems for the same reasons as in the model of M. Faraday engine. The first unipolar motor, the Barlow wheel, was created by Peter Barlow, describing it in the book “The Study of Magnetic Attractions,” published in 1824. The Barlow wheel was two copper gears located on the same axis. As a result of the interaction of the current passing through the wheels with a magnetic field of permanent magnets, the wheels rotate in mutually opposite directions. The current collection is carried out from electrically unconnected axes of the disks, the teeth of which are gear-connected to the output shaft and close the electric circuit of these wheels.

The closest analogue of the claimed technical solution is a non-contact and brushless DC motor, known from the patent of the Russian Federation No. 2391761, published in the bulletin No. 16 of 06/10/2010 [7]. The indicated brushless DC motor contains a fixed stator and a rotor with an axis of rotation, and it differs in that the stator is made in the form of a hollow cylindrical magnetic core, inside of which are placed at its ends the first and second sections of several ring edges of the magnetic conductor each, in the first and second sections of the annular ribs of the magnetic conductor on their entire surface is fixed respectively the first and second rib-cylindrical electrical conductor, both of these rib-cylindrical electrical conductors and the stator is made of copper foil by gluing or by spraying a layer of copper on the surface of the annular ribs of the first and second magnetic conductors and do not have electrical contact with them, the inner ends of the first and second rib-cylindrical electric conductors are connected to the inner copper ring electrodes, and their outer ends are connected to external copper ring electrodes through copper cap-connectors, the rotor is made in the form of a cylindrical electromagnet with two identical first and second located at its ends sections of several annular ribs of the magnetic conductor, for example, steel, which enter the grooves of the first and second sections of the stator annular magnetic circuits with small gaps between them, in the middle part of the rotor there is a magnetization winding fixedly and non-contact to it coaxially, one end of which is connected to the first inner a copper ring electrode of the first rib-cylindrical electric conductor, and the second to the second outer copper ring electrode of the second rib-cylindrical electric conductor Single, the engine output terminals respectively connected to the first external electrode of the first annular copper finned tubular electrical conductor and the second internal copper ring electrode of the second finned cylindrical electrical conductor.

A disadvantage of the known closest analogue (prototype) with respect to the claimed device is the low resistance of the synthesized working winding mounted on a fixed stator, which increases losses on the supply wires between the motor and the low-voltage direct current source, reducing the efficiency of converting electrical energy into mechanical energy.

These disadvantages of the known analogue are eliminated in the claimed technical solution.

The objectives of the invention are to increase the energy efficiency of a brushless DC motor with missing sliding contacts, as well as simplifying the design and increasing the reliability and durability of its action.

These goals are achieved in a brushless two-rotor DC motor containing a rotating magnetized windingless rotor and a fixed toroidal stator with a working winding superimposed on it, as well as a rotor magnetization coil mounted on a stator, characterized in that an additional windingless rigidly connected to the axis of rotation of the rotor is inserted into it a rotor in the form of a magnetically conducting cylinder with an additional magnetization coil fixed to the stator body, both rotating rotors with their common the axis of rotation are their magnetic poles of the same name, respectively, with the inner and outer surfaces of the toroidal stator with the formation of two cylindrical magnetic gaps, inside of which are installed non-magnetic cylinders adjacent to the toroidal stator, on which the working winding of the toroidal stator is wound, the turns of which are passed through the holes in the latter half windings of the working winding are in close proximity (with a minimum permissible gap) from the cylindrical surfaces of both rotating rotors, both rotor magnetization coils and the working winding of the toroidal stator are connected in series or parallel to a direct current source, and the two independent magnetic circuits “rotor – toroidal stator” and “additional rotor – toroidal stator” are closed through magnetically connected rotors magnetic conductive washers fixed to the bodies of their rotors, with the minimum allowable gaps with the stationary magnetic conductive walls of the toroidal stator; wherein the wall thickness of non-magnetic cylinders is selected five to ten times the gap between the conductors of the working winding of the toroidal stator and the cylindrical surfaces of the rotating rotors.

The achievement of the objectives of the invention in the claimed technical solution is explained, firstly, by the multi-turn working winding of the toroidal stator, which significantly increases the efficiency of the motor due to a significant reduction in losses on the supply conductors from the current source, and secondly, by doubling the arising unidirectional torques acting on both rotating rotors, since the half-turns of the working winding are located respectively in two working magnetic gaps, and, thirdly, by the location of the working half-turns of this coils in the immediate vicinity of the rotating rotors and further from the inner and outer cylindrical surfaces of the toroidal stator, which leads to a redistribution of forces acting in the interaction of magnetic fields on the toroidal stator and the corresponding two rotors in favor of the latter.

The invention is clear from the presented drawings.

Figure 1 shows the Central section of a side view of the inventive engine, containing the following elements:

1 - fixed, connected to the motor housing toroidal stator with its magnetically conductive cover (in the figure on the right),

2 - half-turns of the working winding of the toroidal stator 1, located near the surface of the rotating windingless rotor,

3 - half-turns of the working winding of the toroidal stator 1, located near the surface of an additional windingless rotor made in the form of a hollow magnetically conducting cylinder,

4 - non-magnetic (dielectric) cylinder, adjacent to the inner surface of the magnetic pole of the toroidal stator,

5 - additional non-magnetic (dielectric) cylinder, adjacent to the outer surface of the magnetic pole of the toroidal stator with a cylindrical extension (to the right in Fig. 1) for attaching an additional magnetizing coil of the additional rotor to it,

6 - magnetically conductive cover of the toroidal stator (Fig. 1 on the left),

7 - a rotating windingless rotor with a magnetizing cylinder with a central hole in it (left) and a segment of the axis of rotation (right),

8 - magnetic rotor washer 7, mounted on a tight fit with the magnetization cylinder of the rotor 7, with an external axis of rotation (right) and a segment of the axis of rotation (left),

9 - magnetization coil of the rotor 7,

10 - additional windingless rotor rigidly fixed to the axis of rotation by tight fit it with a segment of the axis of rotation of the rotor 7,

11 - magnetic conductive washer, mounted with a magnetization cylinder of the additional rotor 10,

12 - additional magnetization coil of the additional rotor 10, rigidly fixed to the body of a stationary toroidal stator 1 through the outlet of a non-magnetic (dielectric) cylinder 5,

13 - the cover of the engine housing (left in Fig. 1),

14 - a hollow non-magnetic cylindrical motor housing with landing grooves for communication with the cover 13 and the magnetically conductive wall 6 of the toroidal stator 1,

15 - outer bearings of the engine,

16 - the internal bearing of the engine,

17 - conclusions of the working winding (its half-turns 2 and 3) of the toroidal stator 1,

18 - the conclusions of the serially connected magnetization coils 9 and 12 of the windingless rotors 7 and 10, respectively (lead wires are not specified).

Fig. 2 shows a front view of the disassembly of the engine with an indication of the relative position of part of its elements in two working magnetic gaps, magnetic poles formed on the cylindrical surfaces of rotors 7 and 10 (N) and toroidal stator 1 (S), and the directions of the magnetic field in two working magnetic gaps with intensity vectors of these magnetic fields H ₁ and H ₂ . Rotors 7 and 10 are connected with a single axis of rotation, experiencing the action of unidirectional torques from the interaction of magnetic fields formed in the corresponding magnetic gaps and current in the half-turns of the working winding of the toroidal stator 1. The direction of these currents in the half-turns 2 and 3 of the working winding is shown by arrows in Fig. one. Curly arrows show the direction of rotation of the rotors 7 and 10.

Figure 3 shows a linear scan of a part of two cylindrical magnetic gaps indicating the partial forces arising from the opposite pair of half-turns 2 and 3 of the working winding of the toroidal stator 1 in accordance with the law on electromagnetic induction and Newton's third law. These unidirectional partial forces add up according to the number of turns n of the working winding, creating the resulting rotational moments M ₁ and M ₂ for the corresponding two rotors 7 and 10. According to the “left hand” rule, partial forces act on half-turns 2 and 3 (for each of half-turns 2 and 3), respectively, F ₁ and F ₂ when the direct current I flows in the working winding of the stator 1 in transverse magnetic fields with intensities H ₁ and H ₂ . The thickness of non-magnetic (dielectric) cylinders 4 and 5 is hd, where d is the diameter of the conductor of the working stator winding. The gap between the half-turns 2 and 3 and the corresponding cylindrical surfaces of the rotors 7 and 10 is ε << h and is comparable with the diameter of the conductor d, wound round to round from the side of the rotor 7 (from the side of the rotor 10 half-turns have a non-zero gap between themselves, since R ₁ + ε <R ₂ - ε, namely 2ε << R ₂ -R ₁ ). The wall thickness of the non-magnetic (dielectric) cylinders 4 and 5 is equal to hd. To skip the turns of the working winding of the toroidal stator 1 when it is wound in the body of the magnetically conductive stator outside the magnetic gaps, drilling is done in a “checkerboard pattern” in two lines. The latter ensures the normal functioning of the stator magnetic circuit, without increasing its magnetic resistance. These drills are not shown in Fig. 3. In the figure, for simplicity, adjacent turns of the working winding are shown with a noticeable gap.

Consider the action of the inventive brushless two-rotor DC motor (BDDPT).

According to the rule of the “left hand” in a transverse magnetic field with a magnetic field strength N (in amperes per meter), a conductor of length L (in meters) with current I (in amperes) is affected by the partial Lorentz force F equal to F = µ _O LI Н ( in Newtons), where µ _O = 1.256 · 10 ^-6 Gn / m is the magnetic constant. Therefore, in the notation in Fig. 3, we have F ₁ = µ _o LIH ₁ and F ₂ = µ _o LIH ₂ .

In accordance with Newton’s third law (the force of action is equal to and opposite to the reaction force), the action forces F ₁ and F ₂ on half-turns 2 and 3 of the working winding of the stator 1 (see Fig. 3) determine the same in magnitude, but oppositely directed reaction forces, applied to the sources of transverse magnetic fields H ₁ and H ₂ , respectively, to the stator 1 and both rotors 7 and 10. These reaction forces as resultants decompose into essentially equal components F _POT - rotor and F _CT - stator, where F _POT <<F _CT , since h >> ε.

It is easy to understand that F _ROT ² + F _ST ² + 2 F _ROT F _ST cos β = F ² , where β is the angle between the vectors F _ROT and F _ST , therefore, we obtain the decomposition of the opposing force F into components in the form F _ROT ≈ F { 1 + cos [π (ε + d / 2) / (h + ε)]} / 2 and

F _CT ≈ F {1 - cos [π (ε + d / 2) / (h + ε))] / 2 taking into account the proximity β → π / 2,

where 0≤ε + d / 2≤h + ε, where h + ε is the distance between the poles of the magnetic gaps for independent rotor-stator systems.

Then the total force F _{POT Σ1} acting tangentially on the rotor 7 (internal) is equal to F _{POT Σ1} = n F _POT1 = n µ _o LIH ₁ {1 + cos [π (ε + d / 2) / (h + ε) ]} / 2, and the total force acting tangentially on the additional rotor 10 (external) is equal to F _{POT Σ2} = n µ _o LIH ₂ {1 + cos [π (ε + d / 2) / (h + ε)] } / 2.

It is easy to understand that the rotational moment M ₁ applied to the rotor 7 is defined as M ₁ = R ₁ F _{ROT Σ1} , and the rotational moment M ₂ applied to the additional rotor 10 is equal to M ₂ = R ₂ F _{ROT Σ2.} Since both of these torques coincide in direction, the total rotational moment M _Σ on the axis of rotation of the engine is the sum of the moments M ₁ and M ₂ , that is, we have M _Σ = n µ _о LI (R ₁ H ₁ + R ₂ H ₂ ) { 1 + cos [π (ε + d / 2) / (h + ε)]} / 2. If in a first approximation we assume that cos [π (ε + d / 2) / (h + ε)] ≈1, then for M _Σ we get M _Σ ≈n µ _о LI (R ₁ H ₁ + R ₂ H ₂ ) .

When performing a single-layer winding of the working winding of a toroidal stator 1 turn to turn with a conductor diameter d on the inner diameter of a non-magnetic cylinder 4, the number of turns is equal to n = 2π (R ₁ + ε) / d≈2π-R ₁ / d, since R ₁ > d. Then M _Σ ≈ 2 π R ₁ µ _о LI (R ₁ H ₁ + R ₂ H ₂ ) / d. If the ampere turns in the additional magnetization coil 12 with respect to the ampere turns of the magnetization coil 9 are chosen so that the equality R ₁ H ₁ = R ₂ H ₂ is satisfied, which, of course, is always feasible, we obtain a simplified expression for the total torque on the axis of the engine equal to M _Σ ≈4 π R ₁ ² µ _о LIH ₁ / d. If the magnetization coil 9 creates a magnetic flux Ф ₁ , then the induction В ₁ = μ _о Н _{1 of the} magnetic field, to a first approximation, in the working magnetic gap is defined as B ₁ = Ф ₁ / S _POT1 , where S _POT1 = 2 π R ₁ L - the area of the magnetic pole of the rotor 7 (assuming that the length of the rotor-pole is equal to the length of the half-turns 2 (Fig. 1), whence for the magnetic field H ₁ we get the ratio H ₁ = B ₁ / µ _o = Ф ₁ / µ _о S _POT1 = Ф _1/2 π µ _о R ₁ L. Substituting the obtained value of H ₁ in the formula for М _Σ , we obtain M _Σ ≈4πR ₁ ² µ _o LI Ф ₁ / 2π µ _o R ₁ L d = 2 R ₁ I Ф ₁ / d = 2 R ₁ n I Ф _1/2 π R ₁ = n IF ₁ / π.

Analyzing the obtained expression for M _Σ ≈n I Ф ₁ / π, we note that the torque does not directly depend on the geometry of the rotor 7 — its length L and radius R ₁ , but is determined only by ampere-turns of the working winding of the toroidal stator 1 and magnetic flux Ф ₁ created by the bias coil 9, which, in turn, is determined by the ampere turns of this bias coil.

However, the product n I is determined by the permissible current density j in the working winding (for a copper conductor it can be assumed that j = 10 A / mm ² ) and radius R ₁ , since n = 2 π R ₁ / d. For the current I have the expression I = π jd ^2/4. Then to obtain the product of n I n I = (2 π R ₁ / d) (π jd ^2/4) = π ² j R ₁ d / 2 (values ₁ and R d are taken in millimeters). Therefore, M _Σ ≈n I Ф ₁ / π = π j R ₁ d Ф _1/2 , that is, the total rotational moment on the motor axis increases proportionally with increasing radius R ₁ for a given diameter d of the applied copper conductor and a given value of the magnetic flux Ф ₁ created by the magnetization coil 9. The same reasoning applies to the second magnetic circuit from the toroidal stator 1 and additional rotor 10 under the assumption that R ₁ H ₁ = R ₂ H ₂ , as well as when Ф ₁ = Ф ₂ .

The net power on the axis of rotation of the engine is equal to the P _axis = ω | M _Σ |, where ω is the circular frequency of rotation of the rotors 7 and 10.

As already mentioned above, the working winding of the toroidal stator 1 can be connected to a constant current source regardless of the supply of magnetization coils (usually connected in series with each other) or in series with these coils. In the latter case, the conductors of all windings are made of the same copper conductor (over its cross section), which minimizes losses on the supply conductors from a single DC source.

The considered type of a brushless two-rotor DC motor compares favorably with all known collector motors in the absence of their unreliable element - a collector with brushes and in general the absence of any sliding contacts that reduce the reliability and durability of the known motors. In collector motors, only one of the many sections of the rotor winding simultaneously operates. In this type of engine, the entire working winding of the toroidal stator is constantly working, which increases the energy of the engine. During its operation, there are no transients characteristic of DC collector motors due to the high-frequency switching of sections of the winding of its rotor. This helps to increase the rotational speed of the rotors of the inventive engine and the absence of radiation in a wide range of radio interference. In addition, this leads to an increase in the specific net power on the motor shaft per unit volume (weight).

The assembly of the inventive engine is not difficult, since it consists of several detachable parts, as can be seen in Fig. 1 (these parts are separated by a dotted line).

Industrial production of the inventive type of engine is of great interest for technical means that require increased reliability of their work and long service life. For example, such engines can be used in hybrid vehicles.

Literature

1. L.D. Landau, E.M. Lifshits. Electrodynamics of Continuous Media, 2nd ed. M., 1982.

2. J. Jackson. Classical electrodynamics, per. from English M., 1965.

3. D.V. Sivukhin. General course of physics, 2nd ed., Vol. 3. Electricity. M., 1983.

4. Electric unipolar machines, ed. L.A. Sukhanova. M., VNIIEM, 1964, p. 14.

5. "Electricity", No. 8, 1991, p.6-7, Fig.8.

6. British patent No. 2223628 A.

7. O.F. Smaller. Brushless DC motor. RF patent No. 2391761, publ. No 16 on 06/10/2010.

Claims (1)

A brushless two-rotor DC motor containing a rotating magnetized windingless rotor and a fixed toroidal stator with a working winding superimposed on it, as well as a rotor magnetization coil mounted on a stator, characterized in that an additional windingless rotor in the form of a magnetic core is rigidly connected to the axis of rotation of the rotor a cylinder with an additional magnetization coil attached to the stator body, both rotating rotors with their common axis of rotation are their with the same magnetic poles, respectively, with the inner and outer surfaces of the toroidal stator with the formation of two cylindrical magnetic gaps, inside of which are installed non-magnetic cylinders adjacent to the toroidal stator, on which the working winding of the toroidal stator is wound, the turns of which are passed through the holes in the last, and the corresponding half-turns of the working winding are in close proximity (with a minimum permissible gap) from the cylindrical surfaces of both rotating rotors s, both magnetization coils of the rotors and the working winding of the toroidal stator are connected in series or parallel to a direct current source, and two independent magnetic circuits “rotor - toroidal stator” and “additional rotor - toroidal stator” are formed through magnetically conducting washers magnetically connected to their rotors, fixed with the bodies of their rotors, with the minimum permissible gaps with the fixed magnetically conducting walls of the toroidal stator; wherein the wall thickness of non-magnetic cylinders is selected five to ten times the gap between the conductors of the working winding of the toroidal stator and the cylindrical surfaces of the rotating rotors.

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