JP4479097B2 - Reluctance motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a synchronous motor using reluctance torque. In particular, the rotor of a reluctance motor can be easily self-started even when a load having a large resistance torque is connected to a commercial power source and a low-noise reluctance motor can be obtained. Is an improvement.
[0002]
[Prior art]
FIG. 8 is a front view of a rotor core of a conventional reluctance motor, and FIG. 9 is a front view of a stator core and a rotor core.
In FIG. 8, reference numeral 1a denotes a rotor core punched plate in which a thin metal member such as an electromagnetic steel plate is formed in a circular shape, and the rotor core punched plate 1a is inserted into a rotating shaft (not shown) at the center of the circular shape. A hole 1b for inserting the rotation shaft is provided. 2a, 2b, and 2c are long grooves formed in multiple layers by punching such as pressing at a predetermined interval of one or more layers per one pole in the radial direction, and even poles are arranged in a circular radial direction. The long grooves 2a, 2b, and 2c do not have a secondary conductor but are an air layer.
Reference numeral 11 denotes a rib provided in the radial direction at the center of the long grooves 2a, 2b, and 2c in order to ensure the strength of the rotor core blank 1a. Further, the outermost peripheral portion 1c of the rotor core blank 1a is connected with a thickness of about 0.35 mm or less. A large number of the rotor core blanks 1a formed in this way are stacked so as to have a predetermined rotor core width, and fixed by crimping caulking to constitute the rotor core 1 to form the rotor 8 (FIG. 9).
Next, the stator core will be described.
In FIG. 9, reference numeral 7 denotes a stator core punch plate in which a thin metal member such as an electromagnetic steel plate is formed in a donut shape. A large number of slots 7a are arranged radially on the inner peripheral portion of the stator core punch plate 7, A large number of plates 7 are laminated and fixed by crimping caulking, and a stator winding 7b is formed by winding a stator winding (not shown) in the slot 7a.
The rotor 8 and the stator 7b are formed as described above, and the rotor 8 shown in FIG. 8 is provided through the stator 7b and a slight gap 9.
[0003]
Next, the direction in which the magnetic flux and current flow between the rotor 8 and the stator 7b formed as described above will be described with reference to FIG.
In the configuration of the stator 7b and the rotor 8 described above, a current flows to the stator side by connecting the stator winding to a three-phase AC power source. This current is shown in FIG. Flows in the direction from ● (from the back side to the front side). Magnetic flux is generated by the flow of current, and the direction in which the magnetic flux flows is indicated by reference numeral 14 in the figure. When this magnetic flux flows, N pole and S pole are formed, and the rotor 8 starts to rotate in a predetermined direction. In this case, the magnetic flux flows from the N pole to the S pole, but a part of the magnetic flux flows from the N pole to other than the S pole (leakage), so that the characteristics are deteriorated.
[0004]
As described above, this reluctance motor is a motor that rotates with the reluctance torque generated by the difference in the magnetic resistance between the q-axis of the core-extracting direction of the rotor 8 shown in FIG. 10 and the d-axis whose electrical angle is orthogonal to the q-axis. The reluctance torque increases as the difference between the d-axis and q-axis magnetic resistances increases.
In the case of a reluctance motor that rotates at a high speed, it is necessary to ensure the strength of the rotor 8, and the rib 11 at the center of the long grooves 2a, 2b, and 2c shown in FIG. 8 is connected to the outermost periphery 1c of the rotor. The strength of the rotor 8 is ensured by securing the thickness of the portion to some extent.
[0005]
In the conventional reluctance motor in which the long grooves 2a, 2b and 2c of the rotor core 1 are arranged in a plurality of sets at a predetermined interval in the radial direction with one or more layers per pole, the long grooves 2a, 2b and 2c are generally formed in the rotor 8 This tendency is conspicuous in a reluctance motor having a projecting shape in the axial center direction, having multiple layers and elongated long grooves 2a, 2b, and 2c, and in particular, having three or more long grooves 2a, 2b, and 2c. In order to make the gap 9 between the stator 7b and the rotor 8 uniform, it is conceivable to process the outer periphery of the rotor 8, but the inside of the long groove is also a cavity, and the thickness of the outermost periphery of the rotor is about 0.35 mm or less. Processing was difficult because they were thin and connected.
Further, in order to process the outer diameter of the rotor 8, a thickness of the rotor outermost peripheral portion 1c is increased to provide a machining allowance, and after the rotor is formed, the thickness of the rotor outermost peripheral portion 1c is set to about 0.5 mm to 1 mm or more. However, there was a limit in cutting due to problems such as core deformation.
[0006]
[Problems to be solved by the invention]
Since the rotor 8 of the conventional reluctance motor does not have a secondary conductor in the long grooves 2a, 2b, and 2c, it cannot be self-started with a commercial power supply like a general induction motor. Therefore, there is a problem that an expensive control device is required because it must be started by a dedicated amplifier.
In addition, the rotor 8 is a thin metal member that is a member of the rotor core blank 1a, and is likely to be distorted during manufacture. Further, the thin metal member is stamped into a rotor core blank 1a of a predetermined size by pressing, and a large number of sheets are laminated. Therefore, depending on the manufacturing error, it is necessary to machine the rotor outer diameter. However, the outermost peripheral portion 1c of the rotor core blank 1a is as thin as 0.35 mm or less, and the outermost peripheral portion of the rotor shown in FIG. Outer diameter processing was not easy because the connecting portion 1c was broken by processing.
In addition, since the rotor 8 formed by laminating thin metal members and crimping caulking is not strong enough to process the outer diameter of the rotor 8, the outer diameter of the rotor 8 can be processed by cutting / grinding and cannot be made into a perfect circle. The air gap 9 in FIG. 8 becomes non-uniform, and a large magnetic noise is likely to occur. At the same time, since the air gap 9 is not uniform, the leakage magnetic flux increases, leading to a decrease in the salient pole ratio, and there is a problem that the efficiency and power factor of the reluctance motor are remarkably reduced.
[0007]
An object of the present invention is to provide a reluctance motor capable of self-starting so as to quickly rise to a synchronized state without requiring a large-scale start-up control device and reducing magnetic noise without deteriorating electrical characteristics. It is.
[0008]
[Means for Solving the Problems]
A reluctance motor according to the present invention is a reluctance motor including a rotor that has a secondary conductor and is formed of a circular thin metal member and is configured by laminating and fixing a large number of rotor cores having a rotor shaft through hole at the center. , Projecting in the direction of the rotor shaft through-hole around the rotor shaft through-hole, and forming a long groove constituting a magnetic pole by being arranged in a plurality of blocks, and the core radial dimension of the long groove from the rotor shaft center portion is formed. A part of the groove width of both side portions in the long groove portion extending to a position of 1/2 or more is made narrower than the groove width of the other long groove portion, and the long groove is filled with the secondary conductor.
[0011]
The outer diameter of the rotor core is processed.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
1 is a front view of a stator core and a rotor core of a reluctance motor according to Embodiment 1 of the present invention.
In FIG. 1, reference numeral 7 denotes a stator core punch plate in which a thin metal member such as an electromagnetic steel plate is formed in a donut shape. A large number of slots 7a are arranged radially on the inner peripheral portion of the stator core punch plate 7, A large number of plates 7 are stacked and fixed by crimping, and a stator is formed by winding a stator winding (not shown) in the slot 7a.
A rotating magnetic field is generated by connecting a three-phase AC power source to the stator winding. A large number of rotor cores, which will be described later, are stacked on the rotor 8, and the rotor 8 is provided through the stator core 7 and a small gap 9.
[0013]
Next, the rotor core will be described.
In FIG. 2, 1a is a rotor core blank made of a thin metal member such as an electromagnetic steel plate, and is arcuately curved in the central axis direction of the outer circumference circle at each of four locations divided within an angle of 90 ° in the circumferential direction. Thus, a plurality of long grooves 2a, 2b, 2c, 2d, and 2e, each set to the same groove width, are processed by press processing, laser processing, or the like so as to be formed in multiple layers. Further, a hole 1b for rotating shaft insertion is provided at the center of the rotor core blank 1a. A large number of rotor core blanks 1a formed in this way are laminated to have a predetermined core width and fixed by crimping caulking or the like to constitute the rotor core 1.
In the above-described embodiment, the long grooves 2a, 2b, 2c, 2d, and 2e have been described using five arc-shaped grooves as an example, but the long grooves are not limited to five layers.
[0014]
The long grooves 2a, 2b, 2c, 2d, and 2e of the rotor core 1 described above are filled with a nonmagnetic conductive material such as aluminum, aluminum alloy, copper, copper alloy, brass, and stainless steel by a die casting method described later. 4a, 4b, 4c, 4d, 4e, and 4f (FIG. 3) are non-magnetic secondary conductors filled in the long grooves 2a, 2b, 2c, 2d, and 2e, and are stacked as shown in FIG. A pair of short-circuit rings 6 are formed at both ends of the rotor core 1 and are electrically connected and connected to the secondary conductor. 5 is an outer diameter of the rotor. As shown in FIG. 3, the rotor 8 in which the long grooves 2a, 2b, 2c, 2d, and 2e of the rotor core 1 are filled with the secondary conductor of the nonmagnetic conductive material and the pair of short-circuit rings 6 is formed. It is inserted into the rotary shaft 15 and fixed and attached by shrink fitting or the like.
[0015]
The direction of current and magnetic flux flow of the rotor 8 described above will be described with reference to FIG.
A rotating magnetic field is generated by connecting the stator windings to a three-phase AC power source, but the direction of current flow is from x (from the front side to the back side of the page) to ● (from the back side to the front side of the page). The direction in which the magnetic flux flows is indicated by 14 in the figure, whereby the north and south poles are alternately formed in the circumferential direction of the rotor 8 so that the rotor 8 is in a predetermined circumferential direction. Rotate to. In addition, since the long grooves 2a, 2b, 2c, 2d, and 2e are filled with the secondary conductor, most of the magnetic flux flows from the N pole to the S pole, so that the long grooves 2a, 2b, and 2c shown in FIG. The characteristics are improved compared to conventional layers.
[0016]
Next, in the rotor described above, the relationship between the number of grooves, electrical characteristics, and die-casting properties will be described with reference to FIG.
The figure shows the relationship between the efficiency and the number of grooves, which is one of the electrical characteristics of the motor obtained as a result of experiments using 7.5KW, 4P reluctance motors. It is efficient in the axial direction. As is apparent from this figure, the efficiency increases when the number of grooves is about 1 to 5, and 5 or more are saturated.
In addition, the experiment was conducted with a width of 0.6 mm to 5 mm for the groove width. However, 2 mm to 3 mm is appropriate if it is determined in consideration of the experimental results, manufacturability (workability), and electric characteristics of the motor. The groove width.
Furthermore, the die-casting property deteriorates almost proportionally as the number of grooves increases from one to two or three.
[0017]
Next, a method for manufacturing the rotor will be described with reference to FIGS.
First, a large number of rotor core blanks 1a are laminated to have a predetermined core width, and then C-shaped cored bars are arranged on both end surfaces of the laminated rotor core blanks 1a to fix the rotor core 1. Next, the rotating shaft insertion hole 1a of the laminated rotor core punching plate 1a is inserted into the core metal in the die cast mold, and the rotor core 1 is clamped and fixed in the die cast mold.
Filling the die-cast mold with a molten metal of a nonmagnetic material such as aluminum, and then applying pressure to the molten metal to fill the long grooves 2a, 2b, 2c, 2d, and 2e of the rotor core 1; A pair of short-circuit rings 6 that are electrically connected and connected to the molten metal in each of the long grooves 2a, 2b, 2c, 2d, and 2e are integrally formed at both ends of the rotor core 1 to constitute the rotor 8.
[0018]
Next, the operation of the reluctance motor will be described.
When the stator winding wound in the stator-side slot 7a in FIG. 1 is connected to a three-phase AC power source, a rotating magnetic field is generated thereby, and the long grooves 2a and 2b of the rotor 8 provided through the gap 9 are provided. The rotor 8 starts to rotate by the electromagnetic force of the current generated in the conductive conductors 2c, 2d, and 2e and the rotating magnetic field. That is, at the start of rotation, the stator and the cage-shaped secondary conductor of the rotor 8 function as an induction motor. Therefore, the reluctance motor is not provided with a conventionally required starting control device, and the reluctance motor itself is self-started. It can start without having the function of.
[0019]
Embodiment 2. FIG.
The second embodiment will be described with reference to FIG.
In the figure, constrictions 3a, 3b, 3c and 3d are provided in a part of each of the long grooves 2a, 2b, 2c, 2d and 2e of the rotor core 1, and a part of the groove is narrowed. When starting, the current concentrates on the upper surface of the rotor core 1 to increase the effective secondary resistance. The so-called skin effect divides the secondary conductor into two grooves, so that most of the current is located on the surface side of the rotor core 1 at the start. The skin effect is further increased by flowing in the long groove conductor, and the starting torque is increased.
In the above embodiment, the positions of the constrictions 3a, 3b, 3c and 3d are provided in the vicinity of the outer peripheral surface of the rotor 8, but this position is not limited to the vicinity of the outer periphery. The constriction need not be provided in all the long grooves.
Needless to say, the long grooves 2a, 2b, 2c, 2d, and 2e are filled with the above-described nonmagnetic conductive material as a secondary conductor.
[0020]
Furthermore, in FIG. 6, in order to effectively provide the constrictions 3a, 3b, 3c, and 3d of the long grooves 2a, 2b, 2c, 2d, and 2e, the rotor is located at a position that is 1/2 or more of the core radial dimension from the center of the rotor shaft. When the constrictions 3a, 3b, 3c, and 3d are provided in the provided long grooves (2a, 2b, 2c, 2d, and 2e), the skin effect can be effectively obtained.
The above-mentioned constrictions 3a, 3b, 3c, and 3d cannot be expected because the skin effect is not very effective even if a constriction is provided in a long groove provided at a position of 1/2 or less of the core radial dimension from the rotor shaft center. .
[0021]
Furthermore, in the above-described embodiments described with reference to FIGS. 2 and 6, nonmagnetic conductive materials such as aluminum, aluminum alloy, copper, copper alloy, brass, and stainless steel are provided in the long grooves 2a, 2b, 2c, 2d, and 2e. In addition, an insulator made of a nonmagnetic material such as ceramics is mixed into the nonmagnetic conductive material in the form of particles, powder, or solid to the nonmagnetic conductive material. 2b, 2c, 2d, and 2e may be filled.
By incorporating a non-magnetic material insulator, the secondary resistance can be increased, thus increasing the starting torque and enabling self-starting even when a load with a large resistance torque is connected to the commercial power supply. It is.
[0022]
Embodiment 3 FIG.
The third embodiment will be described with reference to FIGS.
According to the third embodiment, the long grooves 2a, 2b, 2c, 2d, and 2e are filled with a nonmagnetic conductive material such as aluminum, aluminum alloy, copper, copper alloy, brass, and stainless steel. A pair of short-circuit rings 6 electrically connected to the molten metal thus formed are integrally formed to constitute the rotor 8, and the outer peripheral portion of the rotor 8 is subjected to cutting or grinding.
Since the outer groove was cut or ground after filling the long groove with conductive material and making the rotor solid, the rotor deformation at the time of cutting or grinding can be suppressed. It is possible to achieve both the processing of the outer peripheral portion and the thin wall connection. Since the dimensional accuracy of the outer diameter of the rotor obtained by processing the outer peripheral portion is extremely high, the length of the slight gap 9 between the stator core 7 and the rotor 8 can be configured with a dimensional length of 0.2 mm or less. Since the magnetic flux in the direction q-axis can be increased, the salient pole ratio can be increased, and a reluctance motor with high electrical efficiency and high power factor can be obtained.
In addition, since the outer peripheral portion of the rotor 8 is cut or ground, the gap 9 can be made uniform, noise can be suppressed, and a low-noise reluctance motor can be obtained.
[0023]
Embodiment 4 FIG.
7 is a front view of a rotor core of a reluctance motor according to Embodiment 4 of the present invention. In the figure, this rotor core uses the rotor core shown in the conventional example.
Nonmagnetic conductive materials such as aluminum, aluminum alloy, copper, copper alloy, brass, and stainless steel are filled into the long grooves 4a, 4b, and 4c of the rotor core laminated and fixed to a predetermined core width by die casting. Since a pair of short-circuit rings 6 electrically connected to and connected to the secondary conductors of the nonmagnetic material filled in the long grooves 4a, 4b, and 4c are formed at both ends of the rotor core, the rotor radial direction and circular Mechanical strength can be improved in the circumferential direction.
Since the conductive material is melted and filled in the long grooves 4a, 4b, and 4c, it functions as an induction motor by the stator 1 and the cage-shaped secondary conductor of the rotor 8 at the start of rotation.
With the above configuration, the secondary conductor can be filled more easily and workability can be improved compared to the arc-shaped rotor core in which the above-described long groove (FIGS. 1 and 2) is curved in the opposite direction with respect to the outer circumference circle. Further, since the ribs 11 are provided in the vicinity of the long grooves 4a, 4b and 4c, the strength of the rotor core blank 1a can be ensured.
[0024]
【The invention's effect】
Since the present invention is configured as described above, the following effects can be obtained.
[0025]
A reluctance motor according to the present invention is a reluctance motor including a rotor that has a secondary conductor and is formed of a circular thin metal member and is configured by laminating and fixing a large number of rotor cores having a rotor shaft through hole at the center. Since the long groove forming the magnetic pole is formed in a plurality of blocks and protrudes in the direction of the rotor shaft through hole around the rotor shaft through hole, the long groove is filled with the secondary conductor. It is possible to obtain a reluctance motor capable of self-starting without the need for a motor.
[0026]
In addition, since a part of the groove width of the long groove provided in the rotor core is narrowed, a reluctance motor capable of self-starting without requiring an expensive control device while increasing starting torque and improving electrical characteristics. Obtainable.
[0027]
In addition, among the long grooves provided in the rotor core, the long groove provided at a position of 1/2 or more of the core radial dimension from the center of the rotor shaft has a part of the groove width narrowed. As a result, the reluctance motor capable of self-start without requiring an expensive control device can be obtained.
[0028]
In addition, since the outer diameter of the rotor core has been machined, the starting torque is increased, the electrical characteristics are improved, the self-starting is possible without the need for an expensive control device with low noise, and the reluctance motor has reduced magnetic noise. Can be obtained.
[Brief description of the drawings]
FIG. 1 is a front view of a stator core and a rotor core of a reluctance motor according to an embodiment of the present invention.
FIG. 2 is a front view of a rotor core of a reluctance motor according to an embodiment of the present invention.
FIG. 3 is a perspective view in which a part of a rotor of a reluctance motor according to an embodiment of the present invention is broken.
FIG. 4 is a front view of a rotor of a reluctance motor according to an embodiment of the present invention.
FIG. 5 is a diagram showing the relationship between the number of grooves, electrical characteristics, and die castability of a reluctance motor according to an embodiment of the present invention.
FIG. 6 is a front view of a rotor core according to an embodiment of the present invention.
FIG. 7 is a partially cutaway front view of a rotor according to an embodiment of the present invention.
FIG. 8 is a front view of a rotor core of a conventional reluctance motor.
FIG. 9 is a front view of a stator core and a rotor core of a conventional reluctance motor.
FIG. 10 is an explanatory diagram of a d-axis and a q-axis.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Rotor core, 1a Rotor core punching board, 1b Hole for rotating shaft insertion, 2a, 2b, 2c, 2d Long groove, 3a, 3b, 3c, 3d Constriction, 4a, 4b, 4c, 4d, 4e, 4f Secondary conductor, 5 Rotor outer diameter, 6 Short ring, 8 Rotor.

Claims (2)

In a reluctance motor having a rotor that has a secondary conductor and is composed of a circular thin metal member and is configured by laminating and fixing a large number of rotor cores having a rotor shaft through hole in the center,
Projecting in the direction of the rotor shaft through-hole around the rotor shaft through-hole, and forming a long groove constituting a magnetic pole by being arranged in a plurality of blocks, and of the long groove, the core radial dimension is 1 A reluctance motor characterized in that a part of the groove width of both side portions of the long groove portion extending to a position of 2 or more is made narrower than the groove width of the other long groove portions, and a secondary conductor is filled in the long groove.   The reluctance motor according to claim 1, wherein an outer diameter of the rotor core is processed.

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