WO2024071675A1 - Switched reluctance motor - Google Patents

Switched reluctance motor Download PDF

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Publication number
WO2024071675A1
WO2024071675A1 PCT/KR2023/012099 KR2023012099W WO2024071675A1 WO 2024071675 A1 WO2024071675 A1 WO 2024071675A1 KR 2023012099 W KR2023012099 W KR 2023012099W WO 2024071675 A1 WO2024071675 A1 WO 2024071675A1
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WO
WIPO (PCT)
Prior art keywords
salient pole
rotating
rotor core
rotor
switched reluctance
Prior art date
Application number
PCT/KR2023/012099
Other languages
French (fr)
Inventor
Jeong Cheol Jang
Se Won Park
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New Motech Co., Ltd.
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Filing date
Publication date
Application filed by New Motech Co., Ltd. filed Critical New Motech Co., Ltd.
Publication of WO2024071675A1 publication Critical patent/WO2024071675A1/en

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/22—Rotating parts of the magnetic circuit
    • H02K1/24—Rotor cores with salient poles ; Variable reluctance rotors
    • H02K1/246—Variable reluctance rotors
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K19/00—Synchronous motors or generators
    • H02K19/02—Synchronous motors
    • H02K19/10—Synchronous motors for multi-phase current
    • H02K19/103—Motors having windings on the stator and a variable reluctance soft-iron rotor without windings
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K29/00—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices
    • H02K29/03—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices with a magnetic circuit specially adapted for avoiding torque ripples or self-starting problems
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K29/00—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices
    • H02K29/06—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices with position sensing devices
    • H02K29/08—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices with position sensing devices using magnetic effect devices, e.g. Hall-plates, magneto-resistors
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K2201/00—Specific aspects not provided for in the other groups of this subclass relating to the magnetic circuits
    • H02K2201/06—Magnetic cores, or permanent magnets characterised by their skew

Definitions

  • the present invention relates to a switched reluctance motor. More specifically, the present invention relates to a switched reluctance motor for a multi-cooker or a blender capable of reducing noise and vibration by applying a rotor having a skewed shape.
  • a switched reluctance motor generates a rotating torque by interrupting the power supplied to a coil wound around a stator core through a switching element.
  • the excitation state between the rotor and the stator may vary sequentially, thereby generating a forward rotating torque corresponding to the input pulse signal in the rotor by a magnetic attractive force.
  • the switched reluctance motor is widely used in household electric appliances, such as multi-cookers or blenders, etc., which require control in various directions.
  • the switched reluctance motor generates torque by reluctance due to the magnetic flux generated in a stator winding, and thus there is no permanent magnet and winding for generating magnetic flux in the rotor.
  • a switched reluctance motor has advantages such as a simple structure, low price, and high torque density and efficiency.
  • the switched reluctance motor of prior art comprises a stator, a rotor, a hall sensor for detecting the position of the rotor, and a control unit for applying current to generate a magnetic force in the stator based on the position of the rotor input from the hall sensor.
  • the stator comprises a stator core in which a plurality of fixed salient poles (teeth) are protruding at regular intervals along the inner diameter side, and an excitation coil wound around the fixed salient pole of the stator core generating a predetermined magnetic force by the current applied, wherein a single line of excitation coil is wound around the fixed salient pole maintaining a regular interval to generate a magnetic force of the same polarity when current is applied.
  • the rotor comprises a rotor core on which a shaft is mounted in the center, and rotating salient poles formed at regular intervals along the outer circumference of the rotor core to be attracted toward the excitation coil by the magnetic force generated from the excitation coil at the stator side to rotate the rotor, wherein the rotating salient poles are arranged at regular intervals.
  • the hall sensor detects the position of the rotating salient pole at the rotor side and outputs a position detecting pulse, so as to sequentially drive the excitation coil in synchronization with the position detecting pulse, and interrupts the power supplied to the excitation coil wound around the stator through a switching element.
  • the excitation state between the rotor and the stator may vary sequentially, thereby generating a forward rotating torque corresponding to the input pulse signal in the rotor by a magnetic attractive force.
  • the rotor may be stopped at a predetermined position when a specific excitation state is not varied, and a reverse torque may be generated by controlling the phase of the input pulse signal applied to the switching element starting from the maximum inductance shape.
  • air circulation by the rotation of the rotor receives a predetermined directivity by the rotation of the rotor and flows in a curved line, whereas the fixed salient pole of stator around which the excitation coil is wound and the rotating salient pole of the rotor corresponding thereto protrude in a straight line. Accordingly, as the air flows, the air collides with the fixed salient pole and the rotating salient pole, not allowing smooth flow, and thus the cooling efficiency inside the motor deteriorates and the magnetic force generated from the excitation coil is weakened, thereby deteriorating the reliability of the product.
  • the rotating salient pole of the rotor moves toward the excitation coil by the magnetic force generated from the excitation coil.
  • the rotational force increases when the rotating salient pole is far from the excitation coil, and there is no rotational force when the rotating salient pole coincides with the excitation coil.
  • the torque increases instantaneously when the excitation coil and the rotating salient pole coincide, thereby generating vibration of the rotor.
  • the present inventors suggest a switched reluctance motor with a new structure capable of solving the above problems.
  • the switched reluctance motor comprises: an upper housing 11; a stator assembly 20 comprising a stator core 21 coupled to the upper housing; a rotor assembly 30, positioned inside the stator assembly 20, comprising a rotor core 31 and rotating together with a shaft 32; a lower housing 12 coupled to a lower part of the stator core 21; a fan 35 coupled to a lower part of the shaft 32; a fixed salient pole 21A protruding vertically in a straight line at regular intervals along the inner circumference of the stator core 21; and a rotating salient pole 31A outwardly protruding in a skewed shape at regular intervals along the outer circumference of the rotor core 31, wherein the non-linearity of the torque generated at the time of excitation of the coil 24 of the stator core 21 is distributed in the circumferential direction by the rotating salient pole 31A inclined in the axial direction to offset the non-uniformity of the magnetic force, thereby improving torque density and reducing torque ripple
  • the heat inside the motor generated when the rotor core 31 rotates is guided along the inclined surfaces 310 and 320 of the rotating salient pole 31A and discharged outside through a fan 35 rotating together with the shaft 32 to cool the motor.
  • a protrusion 31A' is protruded at a front end in the clockwise direction of each rotating salient pole 31A of the rotor core 31.
  • the protrusion 31A' formed at a front end in the rotational direction of the rotor core 31 is formed in a curved shape.
  • an inner concave groove 31A'" is formed in the rotating salient pole 31A of the rotor core 31.
  • the present invention has an effect of implementing a switched reluctance motor for a multi-cooker or a blender suitable for high-speed rotation by reducing noise and vibration by reducing torque ripple through magnetic saturation reduction by allowing high-temperature heat generated inside the motor to be discharged smoothly using a rotating salient pole protruding outward in a skewed shape at regular intervals along the outer circumference of the rotor core.
  • the present invention has an effect of securing maneuver stability of the motor by improving the rotational force of the rotor without torque ripple, by improving the magnetic force by reducing the air gap distance between the protrusion of the rotating salient pole and the fixed salient pole at the initial stage when the rotating salient pole and the fixed salient pole face each other.
  • Fig. 1 is a perspective view illustrating a switched reluctance motor according to the present invention
  • Fig. 2 is an exploded perspective view
  • Fig. 3 is a cross-sectional view illustrating a switched reluctance motor according to the present invention
  • Fig. 4 is a plan view of the arrangement of the stator core and rotor core of a switched reluctance motor according to the present invention, wherein a) is an overall plan view and b) is a partially enlarged plan view;
  • Fig. 5 is an exemplary perspective view of a rotor core according to another embodiment of the present invention.
  • Fig. 6 is a plan view of the arrangement of the stator core and rotor core of the switched reluctance motor of Fig. 5, wherein a) is an overall plan view and b) is a partially enlarged plan view.
  • Fig. 1 is a perspective view illustrating a switched reluctance motor according to the present invention.
  • Fig. 2 is an exploded perspective view.
  • Fig. 3 is a cross-sectional view illustrating a switched reluctance motor according to the present invention.
  • Fig. 4 is a plan view of the arrangement of the stator core and rotor core of a switched reluctance motor according to the present invention, wherein a) is an overall plan view and b) is a partially enlarged plan view.
  • the switched reluctance motor comprises an upper housing 11, a stator assembly 20, a rotor assembly 30, a sensor magnet assembly 40 and a hall sensor assembly 50.
  • 32A denotes a shaft connecting member and 52 denotes a printed circuit board.
  • a shaft through-hole 11A through which a shaft passes is formed in the center of the upper housing 11.
  • the stator assembly 20 is configured to supply power through a stator core 21, an upper insulator 22, a lower insulator 23, a coil 24 and a power connector 25.
  • An upper housing 11 is coupled to an upper part of the stator core 21, and a lower housing 12 is coupled to a lower part of the stator core 21.
  • a plurality of fixed salient poles 21A are installed vertically in a straight line at regular intervals along the inner circumference of the stator core 21, and the fixed salient poles 21A performs a teeth function to wind the coil 24.
  • Fig. 2 illustrates eight fixed salient poles 21A, the number of fixed salient poles is not necessarily limited to eight.
  • the rotor assembly 30 of the present invention comprises a rotor core 31, a shaft 32, an upper bearing 33, a lower bearing 34 and a fan 35.
  • the upper bearing 33 is coupled to an upper bearing inserting unit formed by protruding downward from the center part of the inside of the upper housing 11, and supports the rotation of the shaft at an upper part of the shaft 32.
  • the lower bearing 34 is coupled to a lower bearing inserting unit 12A formed by protruding upward from the center part of the inside of the lower housing 12, and supports the rotation of the shaft at a lower part of the shaft 32.
  • the fan 35 is coupled to a lower part of the shaft 32 and positioned inside the lower housing 12. The fan 35 creates an air flow while rotating together with the shaft 32 to cool the heat generated inside the motor.
  • a sensor magnet assembly 40 is coupled to an upper part of the rotor core 31 coupled to the shaft 32 and a lower part of the upper bearing 33, and the sensor magnet assembly 40 rotates together with the shaft 32.
  • the rotating salient pole 31A protrudes radially outward in a skewed shape at regular intervals along the outer circumference of the rotor core 31.
  • Fig. 2 illustrates six rotating salient poles 31A, the number of rotating salient poles is not necessarily limited to six.
  • the rotating salient pole 31A forms inclined surfaces 310 and 320 on the inner surface of the front end and rear end of the rotor core 31, so that when the rotor core 31 rotates clockwise, the heat generated inside the motor is guided along the inclined surface 310 and 320 according to the rotation of the fan 35, and is quickly discharged outside through an air discharge hole 12B formed in the lower housing 12, thereby preventing overheating inside the motor and preventing magnetic force loss due to magnetic saturation.
  • the fixed salient pole 21A of the stator core 21 has a shape protruding in a straight line, whereas the rotating salient pole 31A has a skewed shape with a twisted inclined surface 310 and 320.
  • the length of the rotor core 31 gets longer and the non-linearity of the torque generated during excitation of the coil 24 of the stator core 21 is distributed in the circumferential direction by the rotating salient pole 31A axially inclined to offset the non-uniformity of the magnetic force, thereby improving torque density and lowering torque ripple.
  • the present invention may provide a motor with reduced noise and vibration even when the motor rotates at high speed by preventing instantaneous torque from being generated when the rotor core 31 rotates.
  • the air scattered in the outer circumferential direction by the rotating salient pole 31A is not stagnant on the inner wall surface between the fixed salient poles 21A and is guided downward while being sucked toward the inclined surfaces 310 and 320 of the rotating salient pole 31A having a strong rotational force to be discharged, so that the vibration or noise caused by air discharge may be reduced.
  • both the fixed salient pole 21A and the rotating salient pole 31A have a skewed shape, air stagnation may occur due to a vortex generated through a collision with the air flow rotating in a direction opposite to the rotating direction of the rotor core 31 on the inner wall surface between the fixed salient poles 21A, and thus vibration and noise may occur.
  • Rotation of the rotor core 31 occurs when a current flows through the coil 24 of the opposite fixed salient pole 21A such that the rotor core 31 generates a clockwise rotating force. If a current is supplied to another fixed salient pole 21A when the current flowing through the fixed salient pole 21A is cut off the moment when the rotating salient pole 31A is about to be in line with the fixed salient pole 21A, and the other rotating salient pole 31A approaches the other fixed salient pole 21A, the rotor core 31 rotates smoothly.
  • noise such as the noise made when blowing air out of a balloon may be generated when the air sucked in by the fan 35 and discharged outside is scattered through the narrow gap.
  • Fig. 5 is an exemplary perspective view of a rotor core according to another embodiment of the present invention.
  • Fig. 6 is a plan view of the arrangement of the stator core and rotor core of the switched reluctance motor of Fig. 5, wherein a) is an overall plan view and b) is a partially enlarged plan view.
  • the air gap distance between the protrusion 31A' of the rotating salient pole 31A and the fixed salient pole 21A may be reduced at the initial stage when the rotating salient pole 31A and the fixed salient pole 21A face each other by protruding the protrusion 31A' at the front end in the clockwise direction of the rotating salient pole 31A of the rotor core 31.
  • the magnetic force at the initial stage when the front end of the rotating salient pole 31A and the fixed salient pole 21A face each other may be improved to increase reluctance and reduce torque ripple, thereby inhibiting vibration. Accordingly, the rotational force of the rotor may be improved without torque ripple, thereby securing maneuver stability of the motor.
  • the protrusion 31A' formed at the front end of the rotational direction of the rotor core 31 is formed in a curved shape to have fluidity without air stagnation, so that air may be discharged smoothly and heat stagnation inside the motor may be prevented.
  • the flat part 31A" at the rear end of the rotational direction of the rotor core 31 is formed to have a step by forming a protruding height lower than the protrusion 31A' so as to widen the air contact area, thereby preventing the overheating transmitted to the rotor core 31. Also, since the distance between the fixed salient pole 21A and the rotating salient pole 31A is widened as a whole by the flat part 31A", the noise generated when the air sucked in by the fan 35 and discharged outside is scattered through a wide gap may be prevented.
  • an inner concave groove 31A'" is formed in the rotating salient pole 31A of the rotor core 31, so that the cooling rate for the entire area of the rotor core 31 may be speeded up by the air flow generated when the rotor core 31 rotates.
  • a protrusion 31A' is protrudingly provided at a front end in the rotational direction of the rotor core 31, thereby compensating for the weight reduction of the entire rotor core 31.

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  • Power Engineering (AREA)
  • Synchronous Machinery (AREA)

Abstract

The switched reluctance motor according to the present invention comprises: an upper housing 11; a stator assembly 20 comprising a stator core 21 coupled to the upper housing; a rotor assembly 30, positioned inside the stator assembly 20, comprising a rotor core 31 and rotating together with a shaft 32; a lower housing 12 coupled to a lower part of the stator core 21; a fan 35 coupled to a lower part of the shaft 32; a fixed salient pole 21A protruding vertically in a straight line at regular intervals along the inner circumference of the stator core 21; and a rotating salient pole 31A outwardly protruding in a skewed shape at regular intervals along the outer circumference of the rotor core 31, wherein the non-linearity of the torque generated at the time of excitation of the coil 24 of the stator core 21 is distributed in the circumferential direction by the rotating salient pole 31A inclined in the axial direction to offset the non-uniformity of the magnetic force, thereby improving torque density and reducing torque ripple.

Description

SWITCHED RELUCTANCE MOTOR
The present invention relates to a switched reluctance motor. More specifically, the present invention relates to a switched reluctance motor for a multi-cooker or a blender capable of reducing noise and vibration by applying a rotor having a skewed shape.
In general, a switched reluctance motor (SRM) generates a rotating torque by interrupting the power supplied to a coil wound around a stator core through a switching element. As an input pulse signal is applied to the switching element, the excitation state between the rotor and the stator may vary sequentially, thereby generating a forward rotating torque corresponding to the input pulse signal in the rotor by a magnetic attractive force.
In addition, it is possible to provide various driving controls such as stopping the rotor at a predetermined position when a specific excitation state is not varied, and generating a reverse torque by controlling the phase of the input pulse signal applied to the switching element starting from the maximum inductance shape. Accordingly, the switched reluctance motor is widely used in household electric appliances, such as multi-cookers or blenders, etc., which require control in various directions.
As suggested in Korean Patent No. 10-1987206, the switched reluctance motor generates torque by reluctance due to the magnetic flux generated in a stator winding, and thus there is no permanent magnet and winding for generating magnetic flux in the rotor.
Therefore, compared to ordinary motors, a switched reluctance motor has advantages such as a simple structure, low price, and high torque density and efficiency.
The switched reluctance motor of prior art comprises a stator, a rotor, a hall sensor for detecting the position of the rotor, and a control unit for applying current to generate a magnetic force in the stator based on the position of the rotor input from the hall sensor. The stator comprises a stator core in which a plurality of fixed salient poles (teeth) are protruding at regular intervals along the inner diameter side, and an excitation coil wound around the fixed salient pole of the stator core generating a predetermined magnetic force by the current applied, wherein a single line of excitation coil is wound around the fixed salient pole maintaining a regular interval to generate a magnetic force of the same polarity when current is applied.
In addition, the rotor comprises a rotor core on which a shaft is mounted in the center, and rotating salient poles formed at regular intervals along the outer circumference of the rotor core to be attracted toward the excitation coil by the magnetic force generated from the excitation coil at the stator side to rotate the rotor, wherein the rotating salient poles are arranged at regular intervals.
In the switched reluctance motor of this structure, the hall sensor detects the position of the rotating salient pole at the rotor side and outputs a position detecting pulse, so as to sequentially drive the excitation coil in synchronization with the position detecting pulse, and interrupts the power supplied to the excitation coil wound around the stator through a switching element. At this time, as an input pulse signal is applied to the control unit of the switching element in synchronization with the position detecting pulse of the position detecting unit, the excitation state between the rotor and the stator may vary sequentially, thereby generating a forward rotating torque corresponding to the input pulse signal in the rotor by a magnetic attractive force. In addition, the rotor may be stopped at a predetermined position when a specific excitation state is not varied, and a reverse torque may be generated by controlling the phase of the input pulse signal applied to the switching element starting from the maximum inductance shape.
However, in the prior art, a high-temperature heat is generated inside the motor when the rotor rotates, and when this heat is maintained between the rotor and the stator, the magnetic force generated from the excitation coil is weakened, thereby generating a magnetic saturation state. Accordingly, due to the increase in torque ripple, the motor generates noise and vibration, and thus it is not possible to realize a stable motor implementation.
To this end, this heat is cooled, and in this manner, the fan coupled to a lower part of the shaft rotates together with the shaft and creates an air flow to cool the heat generated inside the motor.
At this time, air circulation by the rotation of the rotor receives a predetermined directivity by the rotation of the rotor and flows in a curved line, whereas the fixed salient pole of stator around which the excitation coil is wound and the rotating salient pole of the rotor corresponding thereto protrude in a straight line. Accordingly, as the air flows, the air collides with the fixed salient pole and the rotating salient pole, not allowing smooth flow, and thus the cooling efficiency inside the motor deteriorates and the magnetic force generated from the excitation coil is weakened, thereby deteriorating the reliability of the product.
In addition, the rotating salient pole of the rotor moves toward the excitation coil by the magnetic force generated from the excitation coil. The rotational force increases when the rotating salient pole is far from the excitation coil, and there is no rotational force when the rotating salient pole coincides with the excitation coil. In other words, since the magnetic force by the excitation coil instantaneously increases at a portion around which the excitation coil is wound, the torque increases instantaneously when the excitation coil and the rotating salient pole coincide, thereby generating vibration of the rotor.
Accordingly, the present inventors suggest a switched reluctance motor with a new structure capable of solving the above problems.
It is an object of the present invention to provide a switched reluctance motor capable of reducing noise and vibration through magnetic saturation reduction by allowing the air cooling the heat inside the motor to flow smoothly while forcibly circulating the air by the rotation of the rotor so as to improve cooling performance.
It is another object of the present invention to secure maneuver stability of the motor by improving the rotational force of the rotor without torque ripple.
The above and other inherent objects of the present invention may all be easily achieved by the description of the present invention described below.
The switched reluctance motor according to the present invention comprises: an upper housing 11; a stator assembly 20 comprising a stator core 21 coupled to the upper housing; a rotor assembly 30, positioned inside the stator assembly 20, comprising a rotor core 31 and rotating together with a shaft 32; a lower housing 12 coupled to a lower part of the stator core 21; a fan 35 coupled to a lower part of the shaft 32; a fixed salient pole 21A protruding vertically in a straight line at regular intervals along the inner circumference of the stator core 21; and a rotating salient pole 31A outwardly protruding in a skewed shape at regular intervals along the outer circumference of the rotor core 31, wherein the non-linearity of the torque generated at the time of excitation of the coil 24 of the stator core 21 is distributed in the circumferential direction by the rotating salient pole 31A inclined in the axial direction to offset the non-uniformity of the magnetic force, thereby improving torque density and reducing torque ripple.
In the present invention, preferably, the heat inside the motor generated when the rotor core 31 rotates is guided along the inclined surfaces 310 and 320 of the rotating salient pole 31A and discharged outside through a fan 35 rotating together with the shaft 32 to cool the motor.
In the present invention, preferably, a protrusion 31A' is protruded at a front end in the clockwise direction of each rotating salient pole 31A of the rotor core 31.
In the present invention, preferably, the protrusion 31A' formed at a front end in the rotational direction of the rotor core 31 is formed in a curved shape.
In the present invention, preferably, an inner concave groove 31A'" is formed in the rotating salient pole 31A of the rotor core 31.
The present invention has an effect of implementing a switched reluctance motor for a multi-cooker or a blender suitable for high-speed rotation by reducing noise and vibration by reducing torque ripple through magnetic saturation reduction by allowing high-temperature heat generated inside the motor to be discharged smoothly using a rotating salient pole protruding outward in a skewed shape at regular intervals along the outer circumference of the rotor core.
In addition, the present invention has an effect of securing maneuver stability of the motor by improving the rotational force of the rotor without torque ripple, by improving the magnetic force by reducing the air gap distance between the protrusion of the rotating salient pole and the fixed salient pole at the initial stage when the rotating salient pole and the fixed salient pole face each other.
Fig. 1 is a perspective view illustrating a switched reluctance motor according to the present invention;
Fig. 2 is an exploded perspective view;
Fig. 3 is a cross-sectional view illustrating a switched reluctance motor according to the present invention;
Fig. 4 is a plan view of the arrangement of the stator core and rotor core of a switched reluctance motor according to the present invention, wherein a) is an overall plan view and b) is a partially enlarged plan view;
Fig. 5 is an exemplary perspective view of a rotor core according to another embodiment of the present invention; and
Fig. 6 is a plan view of the arrangement of the stator core and rotor core of the switched reluctance motor of Fig. 5, wherein a) is an overall plan view and b) is a partially enlarged plan view.
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
Fig. 1 is a perspective view illustrating a switched reluctance motor according to the present invention. Fig. 2 is an exploded perspective view. Fig. 3 is a cross-sectional view illustrating a switched reluctance motor according to the present invention. Fig. 4 is a plan view of the arrangement of the stator core and rotor core of a switched reluctance motor according to the present invention, wherein a) is an overall plan view and b) is a partially enlarged plan view.
As illustrated in Figs. 1 and 2, the switched reluctance motor according to the present invention comprises an upper housing 11, a stator assembly 20, a rotor assembly 30, a sensor magnet assembly 40 and a hall sensor assembly 50. In the drawings, 32A denotes a shaft connecting member and 52 denotes a printed circuit board.
A shaft through-hole 11A through which a shaft passes is formed in the center of the upper housing 11. The stator assembly 20 is configured to supply power through a stator core 21, an upper insulator 22, a lower insulator 23, a coil 24 and a power connector 25.
An upper housing 11 is coupled to an upper part of the stator core 21, and a lower housing 12 is coupled to a lower part of the stator core 21.
A plurality of fixed salient poles 21A are installed vertically in a straight line at regular intervals along the inner circumference of the stator core 21, and the fixed salient poles 21A performs a teeth function to wind the coil 24. Although Fig. 2 illustrates eight fixed salient poles 21A, the number of fixed salient poles is not necessarily limited to eight.
The rotor assembly 30 of the present invention comprises a rotor core 31, a shaft 32, an upper bearing 33, a lower bearing 34 and a fan 35.
The upper bearing 33 is coupled to an upper bearing inserting unit formed by protruding downward from the center part of the inside of the upper housing 11, and supports the rotation of the shaft at an upper part of the shaft 32. The lower bearing 34 is coupled to a lower bearing inserting unit 12A formed by protruding upward from the center part of the inside of the lower housing 12, and supports the rotation of the shaft at a lower part of the shaft 32. The fan 35 is coupled to a lower part of the shaft 32 and positioned inside the lower housing 12. The fan 35 creates an air flow while rotating together with the shaft 32 to cool the heat generated inside the motor.
On the other hand, a sensor magnet assembly 40 is coupled to an upper part of the rotor core 31 coupled to the shaft 32 and a lower part of the upper bearing 33, and the sensor magnet assembly 40 rotates together with the shaft 32.
In the present invention, the rotating salient pole 31A protrudes radially outward in a skewed shape at regular intervals along the outer circumference of the rotor core 31.
Although Fig. 2 illustrates six rotating salient poles 31A, the number of rotating salient poles is not necessarily limited to six.
The rotating salient pole 31A forms inclined surfaces 310 and 320 on the inner surface of the front end and rear end of the rotor core 31, so that when the rotor core 31 rotates clockwise, the heat generated inside the motor is guided along the inclined surface 310 and 320 according to the rotation of the fan 35, and is quickly discharged outside through an air discharge hole 12B formed in the lower housing 12, thereby preventing overheating inside the motor and preventing magnetic force loss due to magnetic saturation.
The fixed salient pole 21A of the stator core 21 has a shape protruding in a straight line, whereas the rotating salient pole 31A has a skewed shape with a twisted inclined surface 310 and 320. Thus, the length of the rotor core 31 gets longer and the non-linearity of the torque generated during excitation of the coil 24 of the stator core 21 is distributed in the circumferential direction by the rotating salient pole 31A axially inclined to offset the non-uniformity of the magnetic force, thereby improving torque density and lowering torque ripple.
Therefore, the present invention may provide a motor with reduced noise and vibration even when the motor rotates at high speed by preventing instantaneous torque from being generated when the rotor core 31 rotates.
In addition, according to the present invention, the air scattered in the outer circumferential direction by the rotating salient pole 31A is not stagnant on the inner wall surface between the fixed salient poles 21A and is guided downward while being sucked toward the inclined surfaces 310 and 320 of the rotating salient pole 31A having a strong rotational force to be discharged, so that the vibration or noise caused by air discharge may be reduced.
If both the fixed salient pole 21A and the rotating salient pole 31A have a skewed shape, air stagnation may occur due to a vortex generated through a collision with the air flow rotating in a direction opposite to the rotating direction of the rotor core 31 on the inner wall surface between the fixed salient poles 21A, and thus vibration and noise may occur.
Therefore, according to the present invention, since the heat generated inside the motor is quickly discharged without being stagnant between the fixed salient poles 21A of the stator core 21, magnetic saturation due to weakening of magnetic force generated in the coil 24 by overheating is prevented, and thus noise and vibration of the motor caused by torque ripple reduction may be reduced.
Rotation of the rotor core 31 occurs when a current flows through the coil 24 of the opposite fixed salient pole 21A such that the rotor core 31 generates a clockwise rotating force. If a current is supplied to another fixed salient pole 21A when the current flowing through the fixed salient pole 21A is cut off the moment when the rotating salient pole 31A is about to be in line with the fixed salient pole 21A, and the other rotating salient pole 31A approaches the other fixed salient pole 21A, the rotor core 31 rotates smoothly. When the current is supplied to the coil 24 of the fixed salient pole 21A selectively and continuously according to the position of the rotating salient pole 31A in the above method, the rotor core 31 continues to rotate, and at this time, when the rotating salient pole 31A rotates clockwise, magnetic resistance increases through power supply at the initial stage of rotation when the front end of the rotating salient pole 31A approaches one side of the fixed salient pole 21A, thereby reducing torque ripple when the rotor core 31 rotates.
To this end, when the distance between the fixed salient pole 21A and the rotating salient pole 31A is narrowed, the magnetic resistance may increase, thereby reducing torque ripple. However, as illustrated in Fig. 4, in order to increase the magnetic resistance at the initial stage of rotation when the front end of the rotating salient pole 31A approaches one side of the fixed salient pole 21A, if the distance (air gap) between the fixed salient pole 21A and the rotating salient pole 31A is narrowed as a whole, excessive heat may be generated when the rotor core 31 rotates, thereby causing magnetic saturation, and reducing the rotational force of the rotor core 31.
In addition, when the distance between the fixed salient pole 21A and the rotating salient pole 31A is narrowed as a whole, noise such as the noise made when blowing air out of a balloon may be generated when the air sucked in by the fan 35 and discharged outside is scattered through the narrow gap.
Fig. 5 is an exemplary perspective view of a rotor core according to another embodiment of the present invention. Fig. 6 is a plan view of the arrangement of the stator core and rotor core of the switched reluctance motor of Fig. 5, wherein a) is an overall plan view and b) is a partially enlarged plan view.
In the present invention, in order to increase the magnetic resistance at the initial stage of rotation when the front end of the rotating salient pole 31A approaches one side of the fixed salient pole 21A, the air gap distance between the protrusion 31A' of the rotating salient pole 31A and the fixed salient pole 21A may be reduced at the initial stage when the rotating salient pole 31A and the fixed salient pole 21A face each other by protruding the protrusion 31A' at the front end in the clockwise direction of the rotating salient pole 31A of the rotor core 31.
Therefore, when the rotor core 31 rotates, the magnetic force at the initial stage when the front end of the rotating salient pole 31A and the fixed salient pole 21A face each other may be improved to increase reluctance and reduce torque ripple, thereby inhibiting vibration. Accordingly, the rotational force of the rotor may be improved without torque ripple, thereby securing maneuver stability of the motor.
In addition, the protrusion 31A' formed at the front end of the rotational direction of the rotor core 31 is formed in a curved shape to have fluidity without air stagnation, so that air may be discharged smoothly and heat stagnation inside the motor may be prevented.
In addition, according to the present invention, the flat part 31A" at the rear end of the rotational direction of the rotor core 31 is formed to have a step by forming a protruding height lower than the protrusion 31A' so as to widen the air contact area, thereby preventing the overheating transmitted to the rotor core 31. Also, since the distance between the fixed salient pole 21A and the rotating salient pole 31A is widened as a whole by the flat part 31A", the noise generated when the air sucked in by the fan 35 and discharged outside is scattered through a wide gap may be prevented.
In the present invention, an inner concave groove 31A'" is formed in the rotating salient pole 31A of the rotor core 31, so that the cooling rate for the entire area of the rotor core 31 may be speeded up by the air flow generated when the rotor core 31 rotates.
Due to the concave groove 31A'", cool air may be transmitted deep inside the rotor core 31, so that the overall heat dissipation rate of the rotor core 31 may be increased. Also, due to the concave groove 31A'", the rotor core 31 may lose weight, resulting in a decrease in rotational force due to weight reduction. However, to supplement the above, a protrusion 31A' is protrudingly provided at a front end in the rotational direction of the rotor core 31, thereby compensating for the weight reduction of the entire rotor core 31.
It should be noted that the description of the present invention described above is merely an example for understanding the present invention, and is not intended to limit the scope of the present invention. It should be construed that the scope of the present invention is defined by the appended claims, and all modifications and alternations of the present invention fall within the protection scope of the present invention.

Claims (5)

  1. A switched reluctance motor, comprising:
    an upper housing 11;
    a stator assembly 20 comprising a stator core 21 coupled to the upper housing;
    a rotor assembly 30, positioned inside the stator assembly 20, comprising a rotor core 31 and rotating together with a shaft 32;
    a lower housing 12 coupled to a lower part of the stator core 21;
    a fan 35 coupled to a lower part of the shaft 32;
    a fixed salient pole 21A protruding vertically in a straight line at regular intervals along the inner circumference of the stator core 21; and
    a rotating salient pole 31A outwardly protruding in a skewed shape at regular intervals along the outer circumference of the rotor core 31,
    wherein the non-linearity of the torque generated at the time of excitation of the coil 24 of the stator core 21 is distributed in the circumferential direction by the rotating salient pole 31A inclined in the axial direction to offset the non-uniformity of the magnetic force, thereby improving torque density and reducing torque ripple.
  2. The switched reluctance motor of claim 1, wherein the heat inside the motor generated when the rotor core 31 rotates is guided along the inclined surfaces 310 and 320 of the rotating salient pole 31A and discharged outside through a fan 35 rotating together with the shaft 32 to cool the motor.
  3. The switched reluctance motor of claim 1, wherein a protrusion 31A' is protruded at a front end in the clockwise direction of each rotating salient pole 31A of the rotor core 31.
  4. The switched reluctance motor of claim 3, wherein the protrusion 31A' formed at a front end in the rotational direction of the rotor core 31 is formed in a curved shape.
  5. The switched reluctance motor of claim 3, wherein an inner concave groove 31A'" is formed in the rotating salient pole 31A of the rotor core 31.
PCT/KR2023/012099 2022-09-30 2023-08-16 Switched reluctance motor WO2024071675A1 (en)

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Application Number Priority Date Filing Date Title
KR1020220125026A KR20240045559A (en) 2022-09-30 2022-09-30 Switched reluctance motor
KR10-2022-0125026 2022-09-30

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WO2024071675A1 true WO2024071675A1 (en) 2024-04-04

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR19990014766U (en) * 1997-10-09 1999-05-06 김형벽 Rotor cooling structure of induction motor
JP2008312348A (en) * 2007-06-14 2008-12-25 Mitsuba Corp Electric motor
KR20110008749A (en) * 2009-07-21 2011-01-27 주식회사 아모텍 Stator having structure of division type skew core, bldc motor using the same, and battery cooling apparatus
KR20130069079A (en) * 2011-12-16 2013-06-26 삼성전기주식회사 Switched reluctance motor
KR101987206B1 (en) * 2017-12-06 2019-06-11 뉴모텍(주) Switched Reluctance Motor

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR19990014766U (en) * 1997-10-09 1999-05-06 김형벽 Rotor cooling structure of induction motor
JP2008312348A (en) * 2007-06-14 2008-12-25 Mitsuba Corp Electric motor
KR20110008749A (en) * 2009-07-21 2011-01-27 주식회사 아모텍 Stator having structure of division type skew core, bldc motor using the same, and battery cooling apparatus
KR20130069079A (en) * 2011-12-16 2013-06-26 삼성전기주식회사 Switched reluctance motor
KR101987206B1 (en) * 2017-12-06 2019-06-11 뉴모텍(주) Switched Reluctance Motor

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