RU2267855C2 - Electric engine - Google Patents

Abstract

FIELD: electric engineering, namely, engineering of electric machines, in particular, electric engines, possible use, for example, for steering servo of an aircraft autopilot for manufacturing simplified electric engine with higher specific energy coefficients.

SUBSTANCE: electric engine consists of rotor with magnetic drive, shaft, bearing lids of non-magnetic material, stator, having U-shaped poles, positioned radially and evenly along circle. Engine is made of two stator parts. Each part of stator is made of one winding, U-shaped poles, positioned on own frame, made of cylindrical part and side walls with radial slits, carrying U-shaped poles. Frames are connected by ends. Poles of one part of stator are positioned in the middle between polar space of another stator part. Rotor poles are magnetically connected to poles of each stator part, are made of same set of rectangular poles with height of side plates being less, than height of middle plates forming additional shelf. Poles of rotor are mounted along engine axis, in slits of non-magnetic bushings, pinned on a shaft on both ends, held in upper part and on end sides. Each frame is made of dielectric material with low heat expansion coefficient. Side walls of frames are made in form of flat thin discs, outer surfaces of which are made with projecting ribs for mounting and holding stator poles on them. Frames are connected by ends and equipped with holding ring and coupling screws, ends of which are held in bearing lids. Value of air gap between rotor and stator poles ranges from 0,25 to 0,8 millimeters. Transverse width of middle plates of rotor poles, forming a shelf towards air gap, is limited by 80-85%. Engine can be made with three-positioned or neutrally positioned switch and with diodes connected to beginnings of windings, or with enabling two-polar device.

EFFECT: increased reliability, simplified construction, increased specific energy coefficients.

5 cl, 9 dwg

Description

The invention relates to electricity, and in particular to electric machines, more specifically to an electric motor, and can be used, in particular, in aviation for the steering servo drive of an autopilot of an aircraft to create a simplified design of an electric motor with higher specific energy indices.

State of the art

Known is an electric machine for autopilot steering servo, made in the form of a single-phase asynchronous capacitor reversible motor (A.I. Bertinov, “Electric Aviation Automation Machines”, Moscow ed., 1961, p. 65).

An induction motor contains a stator, a rotor, a magnetic circuit, a capacitor, necessary to start the engine and its operating mode.

However, the capacitor cannot be optimal in terms of the capacity required to start the engine and its operating mode. The stator winding is difficult to mechanize, especially for small and medium-sized production, the stator winding is performed manually. The length of the frontal parts of the winding exceeds the length of the active part of the wires laid in the groove, which reduces the efficiency. Such an engine is difficult to manufacture.

Known single-phase synchronous jet engine / A.C. No. 155223, 63 g. /, Comprising a rotor, a stator with windings. The stator is made of sheets of electrical steel, teeth cut out in them, and half of the shortened teeth. The stator winding is divided into two parts, each of which is connected through a valve to a single-phase AC network. Under the half poles, the gap is increased, which reduces the torque and power of the jet engine, since in this case the reactance X along the longitudinal axis will be less.

However, this engine at startup does not provide rotation of the motor shaft in a given direction. In addition, complex, expensive dies are required for cutting stator and rotor plates. Each coil, before laying it in the stator, must be insulated over the entire surface, which is done manually in small- and medium-series production.

The winding in the stator must be secured with an insulating wedge clogged in the slots of the stator teeth, which can lead to breaks in the windings. Despite the separation of the windings, the losses in the stator steel are caused by both losses due to eddy currents and hysteresis due to a change in the direction of the magnetic flux when alternating the positive and negative half-waves of alternating current through the stator winding, which reduces the motor efficiency.

Known induction electric machine / Patent No. 2159495, H 02 K 19-06, 19-24, 99 g. /, Containing a rotor with a magnetic circuit, a shaft, bearing caps, a stator containing sets of U-shaped poles located radially, uniformly around the circumference , ring windings, frame made in the form of a spool.

However, this design has U-shaped poles on the rotor, which increases the air gap between the inner turns of the stator winding and the considerable section of the rotor magnetic circuit located between the teeth, which leads to an increase in its inductive resistance, which reduces the power factor (cosine of the angle φ) and worsens the energy and weight and overall performance of the machine. In addition, a short-circuited squirrel cage winding is ineffective for starting the engine, since its rods are laid along the axis of the rotor and when the rotor is stationary, the magnetic flux of the stator winding pulsates along the axis of the rods and does not induce EMF in them when the rotor teeth are at the moment of launch opposite the interpolar (interdental) space of the stator. It is not possible to carry out winding on a solid spool passing under all poles, since the inner diameter of the stator poles is much smaller than the diameter of the spool.

In addition, it is not clear how and on what the poles and stator windings are attached. The squirrel cage winding on the rotor, individual packages of the rotor magnetic circuit, cannot be fitted onto the rotor shaft sleeve without additional details. The use of a separate set of U-shaped poles for each magnetic circuit of the rotor increases the complexity of manufacturing the machine and complicates the mounting of the poles on the rotor. Thus, the design as a whole is overweight, which reduces its specific energy performance (W kg, cosφ). When the engine starts, its rotor cannot provide a certain directional rotation or reverse.

SUMMARY OF THE INVENTION

The objective of the invention is to provide an electric motor that provides a certain directional rotation or reverse, for example, for a steering servo-drive of an autopilot (RSAP) having a reliable start. In addition, the engine must have a sufficiently high specific energy performance.

Moreover, the engine should be made in the form of a simplified design that does not require large costs in the manufacture. It can also be used in household appliances.

In accordance with the invention, the task is achieved in that in an electric motor containing a rotor with a magnitude conductor, a shaft, bearing caps made of non-magnetic material, a stator with U-shaped poles arranged radially, uniformly in circumference, the winding, frame, and stator are made of two parts. Each part is made of one stator winding and U-shaped poles placed on its frame. Each frame is made of a cylindrical part and side walls with radial slots carrying U-shaped poles. In this case, the frames are connected by the ends, and the poles of one part of the stator are located in the middle between the pole space of the other part of the stator. The rotor poles are magnetically connected with the poles of each part of the stator, made of one set of rectangular charged poles with the height of the outer plates less than the height of the middle plate, forming a small ledge. The rotor poles are installed along the axis of the motor in the slots of non-magnetic bushings, mounted on the shaft from both ends, fixed from above and from the end sides.

In addition, each frame is made of a dielectric material with a small coefficient of thermal expansion, the side walls of the frames are made in the form of flat thin disks, the outer surfaces of which are made with protruding notches for installation and mounting of poles and a cylindrical hole with a shoulder for the rotor. The frames are connected by ends and are provided with a non-magnetic locking ring and coupling screws, the ends of which are fixed in the bearing caps, while the locking ring is mounted on the flanges of the frames.

Moreover, the air gap between the poles of the stator and rotor is 0.25-0.8 mm, and the transverse width of the middle plates of the poles of the rotor, forming a protrusion towards the air gap, is limited to 80-85%.

In one particular embodiment, the motor is made with a two-pole, three-position with a neutral position switch, diodes, while the same poles of the first and second parts of the stator are made with a short-circuited coil located on opposite sides of these poles, the ends of the stator windings connected together are connected to two terminals, and the beginning of the windings through diodes D1 and D2 are connected to the third and fourth terminals of the switch to provide reverse when connected to a single-phase alternating current circuit.

In another particular embodiment, the electric motor is made with a bipolar device including diodes, while the poles of the first and second parts of the stator with the same name are made with a short-circuited coil located on the same sides of these poles. The ends of the two stator windings are connected together and connected to the terminal of the bipolar device, and the beginning of the windings through the diodes D1 and D2 are connected to the other terminal of the bipolar device to provide unidirectional rotation when connected to a single-phase alternating current circuit.

Thus, taking into account the above characteristics, the machine can be made as a single-phase synchronous jet electric motor operating in non-reverse mode, or a motor operating in reverse mode.

This embodiment of the engine provides an increase in reliable operation, in particular for an RSAP drive, and will increase the energy performance of the electric motor.

The list of figures in the drawings

The invention is illustrated by drawings, in which

Figure 1 is a longitudinal section of a motor with

a frame made in accordance with the invention;

Figure 2 is a side view of the stator of the electric motor, shown in a reduced form;

Figure 3 depicts a section bB of figure 2, shown in a reduced form;

Figure 4 shows a detailed arrangement of the poles around the circumference of the stator and the placement of short-circuited turns at the ends of the poles of the two parts of the stator for reverse mode when viewed along arrow X (sides A and B) of figure 1;

Figure 5 shows a detailed arrangement of the poles around the circumference of the stator and the placement of short-circuited turns at the ends of the poles of the two parts of the stator for a non-reversible electric motor when viewed along arrow X (sides A and B) of figure 1;

6 shows an electrical connection diagram of windings for connecting a reversible electric motor to a single-phase alternating current network;

7 shows an electrical connection diagram of windings for connecting a non-reversible electric motor to a single-phase alternating current network.

Fig.8 shows a longitudinal section of a rotor;

Fig.9 is a side view of the rotor (with the ring removed).

Information confirming the possibility of carrying out the invention

The electric motor contains a rotor 1 with a magnetic circuit 2, a shaft 3, bearing caps 4 of non-magnetic material. According to the invention, two parts of the stator 5 and 6, two ring windings 7 and 8, each placed on its frame 9 (see FIG. 1), are introduced into the electric motor. Each frame is made of a cylindrical part and side walls 10 with radial slots (see Figs. 2 and 3), bearing U-shaped poles 11 and 12. In this case, the frames are connected by ends, and the poles of each part of the stator 5 and 6 are turned relative to each other a friend around a circle of 180 electrical degrees. The poles 11 of the stator part 5 are located in the middle between the pole space of the other part of the stator 6 (see figure 4).

The poles 2 of the rotor 1 are magnetically connected with the poles of each part of the stator 5 and 6, made of one set of elongated rectangular poles with a height of the outer plates less than the middle plate, forming a small protrusion of 3-4 mm The transverse width of the middle plates of the rotor poles forming a protrusion towards the air gap is limited to 80-85% of the transverse dimensions of the upper surface area of the pole (see Fig. 8).

The rotor poles are installed along the axis of the engine, in the slots of the non-magnetic bushings 13, mounted on the shaft 3 at both ends by a press fit, fixed from above and from the end faces by a ring 22.

Due to the fact that the transverse dimension of the protrusion of the 14 poles of the rotor is limited to 80-85%, and the height of the protrusion 15 is 3-4 mm, the reactance X q along the transverse axis of the rotor decreases (see Fig. 9). According to the results of experiments, an increase in torque occurs.

The proposed shape of the rotor poles makes it possible to increase the torque and power of a synchronous jet engine, since this decreases the reactance along the transverse axis of the rotor when the rotor poles are located in the interstolar space of the stator. The net power of the synchronous jet engine on the shaft is determined by the well-known formula:

where P2 is the net power on the motor shaft;

Xd is the reactance along the longitudinal axis of the engine;

Xq - reactance along the transverse axis of the engine;

Q is the angle of shift between the stator magnetic flux vectors and the longitudinal axis of the rotor in a rotating coordinate system.

In addition, two frames 9 are made of dielectric material with a small coefficient of thermal expansion, the side walls 10 of the frames are made in the form of flat thin disks, the outer surfaces of which are made with protruding cutouts 17 for mounting and fixing poles in them, and a round hole 18 with a shoulder 21 for the rotor (see figure 2 and 3).

The frames are connected by ends and provided with a locking ring 19 of non-magnetic material and coupling screws 20, the ends of which are fixed in the covers 4 of the bearings (see figure 1). In this case, the retaining ring is mounted on the flanges of 21 frames.

The size of the air gap between the poles of the stator and rotor is 0.25-0.8 mm. The size of the gap is minimal, depending on the dimensions of the engine, materials used in the engine and operating conditions (ambient temperature, the effect of resizing parts).

In the motor, the loss in steel is much smaller, since there are no hysteresis losses in it, and eddy current losses are less due to the absence of alternating magnetization reversal of the steel poles of the stator and rotor.

The engine can be made with a bipolar three-position with a neutral position switch (see Fig.6), diodes D1 and D2. The two stator windings 7 and 8 connected together are connected to two terminals, and the beginning of the windings through diodes are connected to the third and fourth terminals of the switch to ensure reverse when the motor is connected to a single-phase alternating current circuit. The same poles of both parts of the stator 5 or 6 can be made with a squirrel-cage coil 16 located on opposite sides of these poles (see Fig. 4), where a detailed circuit of the poles around the circumference of the stator shows short-circuited coils placed on the same poles, in the form arrow X of Fig. 1 on the stator part from side A and the stator part from side B.

The presence of such shielding and an electrical circuit for connecting to a single-phase alternating current circuit allows the engine to operate in reverse mode.

The engine can be made with a switching two-pole device, diodes D1 and D2, while the poles of the first and second parts of the stator of the same name are made with a short-circuited coil 16 located on the same sides of these poles (see Fig. 5), where a detailed arrangement of the poles is shown around the circumference of the stator and the placement of short-circuited turns 16 from side A and B on the two parts of the stator, as seen in arrow X of FIG. 1. The ends of the two stator windings 7 and 8 are connected together and connected to the terminal of the bipolar device, and the beginning of the windings through the diodes D1 and D2 are connected to the other terminal of the bipolar device to provide unidirectional rotation when the motor is connected to a single-phase alternating current circuit (see Fig. 7).

The presence of such shielding (see Fig. 4) and an electrical circuit for connecting a single-phase alternating current circuit (see Fig. 7) allows the engine to operate in a non-reverse mode. In this case, the engine provides twice as much power in comparison with the operation of the engine in reverse mode while maintaining a synchronous rotor speed.

The claimed electric motor has improved energy performance (efficiency and COSφ), increased reliability of starting the engine RSAP.

The operation of the electric motor.

The electric motor operates in reverse mode.

The start and operation of the electric motor in reverse mode (see Fig.6) is carried out by connecting one of the windings 7 or 8 of both parts of the stator through a two-pole three-position with a neutral position switch to a single-phase alternating current network. When it is connected through a diode stator winding connected in series with it, it induces a unidirectional pulsating field at the poles of the stator part, which pulsates in the axial direction in the air gap of the motor. All poles of the stator part on one side have the same polarity, and on the other hand have the opposite polarity. In this case, the shielding of the poles is performed on one side of one part of the stator, and on the opposite side of the other part of the stator.

Due to the shielding of the poles, as shown in FIGS. 4, 5, the poles of the stator part on one side are made with a short-circuited turn, providing displacement of the pulsating field, the motor rotor begins to rotate in a certain direction. Since each of the U-shaped poles consists of two poles proper, for example, on one side of the stator the magnetic flux enters the frame bore, on the other side of the stator part the magnetic flux passing along the rotor poles enters the stator pole. Thus, the electric motor has 12 poles and its speed is determined by the formula:

,

,

where f is the frequency of the alternating current;

p is the number of pairs of poles (in the considered motor n-6 poles);

n is the rotation frequency.

The electric motor can operate with unidirectional rotation in non-reverse mode. Start and operation of the engine is carried out by connecting two windings 7 and 8 to the network through diodes. Since the diode of one winding is connected by an anode and the other cathode to a bipolar switching device (see Fig. 7), the poles of one part of the stator are located in the middle between the pole space of the other part of the stator, the magnetic flux is alternately excited in two parts of the stator.

The motor uses both half-waves of single-phase alternating current, which alternately excite the poles in two parts of the stator, installed with a shift of 180 electrical degrees. This engine provides twice the power compared with the operation of an engine operating in reverse mode while maintaining the same synchronous rotor speed.

In this case, the shielding of the poles of the same sides of both parts of the stator is performed by short-circuited turns (see Fig. 5). If one of the windings breaks, the motor will continue to work with a halved electromagnetic moment.

Thus, the operation of the proposed engine, like any synchronous jet engine, is based on the interaction of a circular rotating magnetic field of the stator with a clearly pole unexcited rotor, which tends to occupy a position corresponding to the maximum magnetic conductivity. In a single-phase motor, the pulsating field is decomposed into two fields rotating in opposite directions. By shielding the poles on one side, the rotor rotates in a certain direction.

Due to the fact that the covers and the shaft are non-magnetic, the eddy current losses induced by the pulsating magnetic flux of the poles and the winding itself are reduced in the motor.

In addition, the absence of magnetization reversal of the stator and rotor poles provides a reduction in steel losses in the absence of hysteresis.

The shape of the rotor poles provides an increase in torque. Moreover, the non-magnetic dielectric frame is lighter than the metal casing, which ensures weight reduction and ease of assembly and execution of the engine. Increasing the efficiency of using windings increases specific energy indicators.

The claimed electric motor has increased overall dimensions, increased reliability of starting the engine RSAP.

Claims (5)

1. An electric motor comprising a two-part stator with U-shaped poles and an annular winding, a rotor with poles drawn from rectangular plates of electrical steel, bearing caps and a shaft of non-magnetic material, characterized in that the rotor poles are made with extreme plates of lower height in compared with the height of the package of middle plates forming a protrusion above the extreme plates, the thickness of the package of middle plates is 80-85% of the total thickness of the pole, each part of the stator is mounted on a frame made of die of electric material with a small coefficient of thermal expansion, and the same poles of the first and second parts of the stator at their end facing the air gap are made with a short-circuited coil covering part of the cross section of the pole to ensure engine starting. 2. The electric motor according to claim 1, characterized in that for ensuring reverse it is equipped with a bipolar three-position switch with a neutral, two diodes, while the same poles of the first and second parts of the stator are made with a short-circuited coil located on opposite sides of these poles related to different parts the stator, the ends of the stator windings connected together are connected to two terminals, and the beginning of the windings through the diodes D1 and D2 are connected to the third and fourth terminals of the switch, the terminals connected to the movable contacts are connected to a single-phase AC network. 3. The electric motor according to claim 1, characterized in that for ensuring unidirectional rotation it is equipped with a bipolar switch, two diodes, while the same poles of the first and second parts of the stator are made with a short-circuited coil located on the same sides of the poles of the parts of the stator, the ends of the two stator windings are connected together and connected to one terminal, and the beginning of the windings through diodes D1 and D2 are connected to another terminal connected to the movable contacts of the bipolar switch, the other two terminals of the bipolar switch They are connected to a single-phase AC network. 4. The electric motor according to claim 1, characterized in that the side walls of the frames are made in the form of flat thin disks, the outer surfaces of which are made with protruding ribs for installation and fastening of the stator poles in them. 5. The electric motor according to claim 1, characterized in that the air gap is selected as a minimum of not more than 0.8 mm based on the possibility of design to increase engine power.

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