Rotor and motor

Abstract

This rotor comprises: a rotor core including a first core accommodation portion and a second core accommodation portion arranged in the circumferential direction of a rotary shaft; and a core assembly including a first core unit accommodated in the first core accommodation portion and a second core unit accommodated in the second core accommodation portion. The core assembly includes: a magnet extending in the direction parallel to the direction of the rotary axis of the rotor core; and a plurality of wire rods which extend in the direction parallel to the direction in which the magnet extends, and which are arranged along the circumference of the magnet.

Description

Rotor and motor

[0001] The present disclosure relates to a rotor of an axial flux motor and an axial flux motor.

[0002] A motor is a device that converts electrical energy into mechanical rotational force and can be used as a power source for various mechanical devices, such as automobiles, transportation equipment, or industrial production equipment. Motors can be used in mechanical devices that require power as rotating machinery, such as drive motors for transportation equipment and drive motors for household use.

[0003] Motors that provide rotational power operate on the principle that rotational torque is generated by the interaction of magnetic field lines occurring in the air gap between the rotor and the stator. In this case, the magnetic field lines crossing the rotor and the stator are called flux links. When the flux links are perpendicular to the rotation axis of the motor, it is called a radial flux motor, and when they are parallel to the rotation axis, it is called an axial flux motor. Due to the characteristics of the flux linkage direction, axial flux motors can utilize the entire surface area of ​​the rotating body for torque generation; thus, they have a high torque density per unit volume, which is advantageous for miniaturizing the motor.

[0004] Axial motors can be used in applications requiring relatively high output, such as electric vehicles. Axial motors can be used in fields requiring rotational power from an electric supply that demand excellent torque responsiveness.

[0005] An axial drive motor can generate rotational torque by inserting strong permanent magnets into the interior of the rotor. The rotor of an axial motor may have a structure in which permanent magnets are fixed to a disc. In such a structure, the magnetic poles of the permanent magnets are directly exposed to the air, which can lead to increased losses due to leakage flux near the corners. Specifically, in this rotor structure, the permanent magnets are directly exposed to the air gap, resulting in leakage flux where the entire flux linkage does not effectively propagate in the axial direction but instead scatters to the periphery of the air gap. This leakage flux does not contribute to the rotation of the motor but rather generates unnecessary harmonic induced electromotive force in both the rotor and the stator, causing a decrease in motor efficiency.

[0006] Meanwhile, since leakage flux is very difficult to predict and control during the design phase, it is typically necessary to increase the volume of permanent magnets or use expensive materials to generate a flux greater than that corresponding to the desired design torque. However, this not only increases the manufacturing cost of the motor but can also be a source of various losses in the motor's operating environment.

[0007] According to one aspect of the present disclosure, a rotor and a motor capable of reducing leakage flux are provided.

[0008] According to one aspect of the present invention, a rotor comprises a rotor core including a first core receiving portion and a second core receiving portion arranged in a circumferential direction of a rotation axis, and a core assembly including a first core unit received in the first core receiving portion and a second core unit received in the second core receiving portion. The core assembly comprises a magnet extending in a direction parallel to the rotation axis direction of the rotor core, and a plurality of wires extending in a direction parallel to the direction in which the magnet extends, the plurality of wires arranged along the circumference of the magnet.

[0009] The above core assembly may include a third core unit accommodated in the first core receiving portion.

[0010] The plurality of wires mentioned above may have a diameter smaller than the diameter of the magnet.

[0011] The plurality of wires mentioned above can be arranged radially around the magnet.

[0012] The above plurality of wires may include ultra-low carbon steel.

[0013] The length of the magnet may be equal to the length of the plurality of wires or longer than the length of the plurality of wires.

[0014] The above plurality of wires can be bonded to the magnet by a non-conductive adhesive.

[0015] Each of the above plurality of wires may be provided to be coated with an insulating material.

[0016] The above plurality of wires may be arranged to surround the magnet.

[0017] The first core receiving portion and the second core receiving portion may be provided such that a cross-section perpendicular to the rotation axis of the rotor core has a polygonal shape.

[0018] The rotor core may include a shaft mounting portion on which a rotating shaft is mounted. The first core receiving portion and the second core receiving portion may be provided along the outer circumference of the shaft mounting portion.

[0019] The rotor may further include a bearing provided between the shaft mounting portion and the rotating shaft.

[0020] The rotor core may include a partition for separating the first core receiving portion and the second core receiving portion.

[0021] According to one aspect of the present invention, a motor comprises a stator, a first rotor provided on a first side in the axial direction of the stator, a second rotor provided on a second side opposite to the first side in the axial direction of the stator, and a rotating shaft mounted on the first rotor and the second rotor. The first rotor or the second rotor comprises a core assembly comprising a rotor core including a shaft mounting portion to which the rotating shaft is rotatably coupled and a core receiving portion provided on the outer circumference of the shaft mounting portion, and a core unit received in the core receiving portion. The core assembly comprises a magnet extending in a direction parallel to the rotational axis direction of the rotor core, and a plurality of wires extending in a direction parallel to the direction in which the magnet extends, the plurality of wires arranged along the circumference of the magnet.

[0022] The rotor and motor according to the embodiments of the present invention are configured such that a wire is arranged along the circumference of the permanent magnet with the permanent magnet at the center, thereby suppressing the flow of leakage magnetic flux and concentrating the flow of magnetic flux in the axial direction of the motor.

[0023] FIG. 1 illustrates a disassembled stator and rotor of a motor according to one embodiment of the present disclosure.

[0024] FIG. 2 illustrates a perspective view of a rotor according to one embodiment of the present disclosure.

[0025] FIG. 3 illustrates a plan view of a rotor according to one embodiment of the present disclosure.

[0026] FIG. 4 illustrates a core unit of a rotor according to one embodiment of the present disclosure.

[0027] FIG. 5 illustrates the analysis results of the magnetic flux linkage of a core unit according to one embodiment of the present disclosure.

[0028] FIG. 6 illustrates the analysis results of the magnetic flux linkage of a permanent magnet of a core unit according to one embodiment of the present disclosure.

[0029] The embodiments described in this specification are merely the most preferred embodiments of the present invention and do not represent all technical concepts of the present invention; therefore, it should be understood that various equivalents or modifications that can replace them at the time of filing this application are also included within the scope of the rights of the present invention.

[0030] Singular expressions used in the description may include plural expressions unless the context clearly indicates otherwise. In the drawings, the shapes and sizes of elements may be exaggerated to provide a clearer description.

[0031] In this specification, terms such as "comprising" or "having" are intended to indicate the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not excluding in advance the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0032] Throughout the specification, ordinal expressions such as “first” and “second” are used to distinguish multiple components from one another, and the ordinals used do not indicate the order of placement, manufacturing order, or importance among the components.

[0033] When it is stated that a component is "connected" to another component, it should be understood that it may be directly connected to that other component, or that there may be other components in between.

[0034] FIG. 1 illustrates a disassembled stator and rotor of a motor according to one embodiment of the present disclosure.

[0035] Referring to FIG. 1, a motor (100) according to one embodiment of the present disclosure may include an axial flux motor having axial flux linkage. The motor (100) may include a rotor (1), a stator (2), and a rotating shaft (3).

[0036] The stator (2) is a fixed part of the motor (100) and may include a coil (2a) and a stator core (2b). The coil (2a) may form a magnetic field as current flows through it. For example, the coil (2a) may be arranged radially. For example, the stator core (2b) may be manufactured by laminating silicon steel sheets. The stator core (2b) may form a path for magnetic flux. For example, the stator (2) may include a cooling structure to reduce heat generation. For example, the stator (2) may have a disc shape. The stator (2) may include a stator hole (2c) through which a rotating shaft (3) passes. The stator hole (2c) may be formed by penetrating the stator (2) in the direction of the rotation axis of the motor (100).

[0037] The rotating shaft (3) can penetrate the stator (2). The rotating shaft (3) can penetrate the center of the stator (2). The rotating shaft (3) can be rotatably coupled to the stator (2).

[0038] The rotating shaft (3) can penetrate the rotor (1). The rotating shaft (3) can penetrate the center of the rotor (1). The rotating shaft (3) can be mounted on the rotor (1). The rotating shaft (3) can transmit rotational motion by the rotor (1). The rotating shaft (3) can be configured to rotate based on the rotation of the rotor (1).

[0039] The rotor (1) is a rotating part of the motor (100) and can be configured to generate rotational force by interacting with the magnetic field created by the stator (2). The rotor (1) rotates by interacting with each other in the air gap due to the current flowing through the coil by the voltage applied to the stator (2) and the magnetic field effect generated by it. For example, the air gap can be formed between the rotor (1) and the stator (2).

[0040] The rotational force generated by the rotor (1) can be transmitted through the rotation shaft (3). For example, the rotor (1) may include a first rotor (1a) positioned on the first side of the stator (2) in the direction of the rotation axis of the motor (100), and a second rotor (1b) provided on the second side opposite to the first side of the stator (2) in the direction of the rotation axis of the motor (100). The rotation shaft (3) may be mounted on the first rotor (1a) and the second rotor (1b).

[0041] FIG. 2 illustrates a perspective view of a rotor according to one embodiment of the present disclosure. FIG. 3 illustrates a plan view of a rotor according to one embodiment of the present disclosure. FIG. 4 illustrates a core unit of a rotor according to one embodiment of the present disclosure.

[0042] Referring to FIGS. 2 through 4, a rotor (1) according to one embodiment of the present disclosure may include a rotor core (10). The rotor core (10) may have a disc shape. The rotor core (10) may form the outer shape of the rotor (1). For example, the rotor core (10) may include a metal and / or non-metal structural material.

[0043] The rotor core (10) may include a shaft mounting portion (16) for mounting a rotating shaft (3). The shaft mounting portion (16) may be provided at the center of the rotor core (10). The shaft mounting portion (16) may be formed by penetrating the rotor core (10) in the direction of the rotation axis. The rotating shaft (3) may be inserted into the shaft mounting portion (16). The rotating shaft (3) may be coupled to the shaft mounting portion (16) and fixed to the rotor (1).

[0044] The rotor (1) may include a bearing (18). The bearing (18) may be provided between the shaft mounting portion (16) and the rotating shaft (3). The bearing (18) may be mounted on the shaft mounting portion (16). The bearing (18) may support the transmission of rotational motion of the rotor (1) to the rotating shaft (3).

[0045] The rotor core (10) may include a core receiving portion (11, 12) for receiving a core assembly (20). The rotor core (10) may be provided to support the core assembly (20). The rotor core (10) may support the core units (20a, 20b, 20c) of the core assembly (20).

[0046] For example, the core receiving portions (11, 12) may be provided in multiple numbers. For example, the core receiving portions (11, 12) may include a first core receiving portion (11) and a second core receiving portion (12). The first core receiving portion (11) and the second core receiving portion (12) may be arranged in the circumferential direction of the rotation axis of the rotor (1). For example, the first core receiving portion (11) and the second core receiving portion (12) may be provided along the outer circumference of the shaft mounting portion (16).

[0047] In FIGS. 1 to 3, the rotor core (10) is shown as including six core receiving portions (11, 12), but the number of core receiving portions (11, 12) is not limited thereto and may be five or fewer or seven or more depending on the number of design poles of the motor (100).

[0048] The core receiving portion (11, 12) may be formed by penetrating the rotor core (10) in a direction parallel to the rotation axis direction. For example, the core receiving portion (11, 12) may be provided so that the cross-section perpendicular to the rotation axis of the rotor core (10) has a polygonal shape. However, the cross-sectional shape of the core receiving portion (11, 12) is not limited to a polygonal shape and may have various shapes depending on the number of design poles of the motor (100).

[0049] The rotor core (10) may include a partition (17) for separating the first core receiving portion (11) and the second core receiving portion (12). The partition (17) may partition the first core receiving portion (11) and the second core receiving portion (12).

[0050] A rotor (1) according to one embodiment of the present disclosure may include a core assembly (20). The core assembly (20) may be mounted on a rotor core (10). The core assembly (20) may include a magnet (21) and a plurality of wires (22). The core assembly (20) may include a core unit (20a, 20b, 20c) comprising a magnet (21) and a plurality of wires (22).

[0051] For example, the core assembly (20) may include a first core unit (20a) received in a first core receiving portion (11) and a second core unit (20b) received in a second core receiving portion (12). The core assembly (20) may include a third core unit (20c) received together with the first core unit (20a) in the first core receiving portion (11). The core assembly (20) may include a plurality of core units (20a, 20b, 20c). The number of core units (20a, 20b, 20c) may vary depending on the design specifications of the motor (100).

[0052] For example, a plurality of core units (20a, 20b) may be provided in the first core receiving portion (11) of the rotor core (10). For example, a plurality of core units (20a, 20c) may be inserted into the first core receiving portion (11). The plurality of core units (20a, 20c) may be arranged so that at least a portion of them come into contact with each other.

[0053] The core assembly (20) may include a magnet (21) configured to generate rotational torque for the rotor (1). The magnet (21) may extend in a direction parallel to the rotational axis direction of the rotor core (10). For example, the magnet (21) may include a permanent magnet. For example, the magnet (21) may be configured to be equal to or longer than the length of a plurality of wires (22). If the length of the magnet (21) is configured to be longer than the length of the plurality of wires (22), it may be effective in increasing the magnetic flux linkage. For example, the magnet (21) may have a circular cylinder shape. The magnet (21) may include a material different from that of the rotor core (10).

[0054] The core assembly (20) may include a plurality of wires (22) extending in a direction parallel to the direction in which the magnet (21) extends. The plurality of wires (22) can prevent magnetic flux generated from the magnet (21) from interlinking in the axial direction and leaking into the surrounding air gap. As the plurality of wires (22) are arranged to surround the magnet (21), the motor (100) can have increased torque and efficiency, and the amount of magnet (21) required for the motor (100) to obtain the same torque can be reduced. A motor (100) according to one embodiment of the present disclosure can reduce its size while maintaining output by providing a plurality of wires (22) around the magnet (21).

[0055] A plurality of wire rods (22) arranged around the magnet (21) are steel wire rods and have a permeability superior to that of air, so a more stable magnetic circulation path can be secured to minimize leakage flux and increase the density of flux linkage to the stator (2).

[0056] A plurality of wires (22) may be arranged along the circumference of the magnet (21). A plurality of wires (22) may be arranged radially around the magnet (21). A plurality of wires (22) may be arranged to surround the magnet (21). A plurality of wires (22) may be arranged to wrap around the magnet (21). A plurality of wires (22) may include a material different from that of the magnet (21).

[0057] The diameter of the plurality of wires (22) can be determined according to the magnitude of the magnetic flux linkage required in the design of the motor (100). For example, the plurality of wires (22) may have a diameter smaller than the diameter of the magnet (21). The diameter of the plurality of wires (22) may be determined based on the number of core units (20a, 20b, 20c) of the core assembly (20) mounted in the core receiving portion (11, 12). For example, the diameter of the plurality of wires (22) may be determined to minimize the remaining space when the core units (20a, 20b, 20c) of the core assembly (20) are inserted into the core receiving portion (11, 12). For example, the diameter of the plurality of wires (22) may be provided to be 1.0 mm or less.

[0058] For example, a plurality of wires (22) may be provided to be equal to or shorter than the length of the magnet (21). For example, a core unit (20a, 20b, 20c) comprising a magnet (21) and a plurality of wires (22) arranged radially around the magnet (21) may be provided to form a plane identical to a plane perpendicular to the rotation axis of the rotor core (10).

[0059] For example, the plurality of wires (22) may include ultra-low carbon steel. For example, the plurality of wires (22) may include steel wire rods containing a small amount of carbon and a large amount of silicon. For example, the plurality of wires (22) may be arranged to be coated with an insulating material. For example, the plurality of wires (22) may be a soft steel material having high permeability and may be arranged to provide a stable path to the magnetic field circulating from the magnet (21).

[0060] For example, a plurality of wires (22) can be bonded to a magnet (21) by a non-conductive adhesive. The rotor (1) can further improve bonding strength and insulation by impregnating the structure in which the magnet (21) and the plurality of wires (22) are bonded. Since the magnet (21) is strongly bonded to the plurality of wires (22) by an insulating material and an adhesive, structural stability can be ensured while the rotor (1) rotates at high speed. Alternatively, the plurality of wires (22) can be firmly bonded to the magnet (21) by mechanical bonding, welding, chemical adhesive, etc.

[0061] A motor (100) according to one embodiment of the present disclosure can generate driving torque through electromagnetic interaction with a stator (2) by installing a core assembly (20) comprising a plurality of wires (22) that surround a magnet (21) in a rotor core (10). For example, the number of core units (20a, 20b, 20c) of the core assembly (20) installed in the rotor core (10) and / or the magnets (21) of the core units (20a, 20b, 20c) can be determined in various ways according to design variables of the motor (100).

[0062] The length of the core assembly (20) may be proportional to the thickness of the rotor (1). For example, if the thickness of the rotor (1) increases, the length of the core assembly (20) may also increase. The thickness of the rotor (1) may increase parallel to the axial direction of the motor (100).

[0063] FIG. 5 illustrates the analysis results of the magnetic flux linkage of a core unit according to one embodiment of the present disclosure. FIG. 6 illustrates the analysis results of the magnetic flux linkage of a permanent magnet of a core unit according to one embodiment of the present disclosure.

[0064] Referring to FIG. 5, the core units (20a, 20b, 20c) of the core assembly (20) according to one embodiment of the present disclosure are composed of a magnet (21) and a plurality of wires (22) arranged to surround the magnet (21). Therefore, compared to the case where the magnet (21) is placed alone without the plurality of wires (22) arranged to surround the magnet (21) as shown in FIG. 6, the maximum value of the magnetic flux linkage in the vertical direction can be increased by approximately 20%. That is, when the magnet (21) is exposed to the atmosphere as shown in FIG. 6, the amount of magnetic flux linkage can be reduced to half the level compared to the case where a plurality of wires (22) are arranged around the magnet (21) as shown in FIG. 5.

[0065] Referring to Table 1 below, the magnitude of the magnetic flux linking in the axial direction can be changed by varying the number and radius of multiple wires (22) arranged along the circumference of the same magnet (21). For example, the radius of the magnet (21) can be 0.5 mm. The magnitude of the magnetic flux linking can be calculated using electromagnetic analysis techniques.

[0066] For example, according to Example 1, when eight wires (22) with a radius of 0.3 mm are arranged along the circumference of the magnet (21), the magnitude of the magnetic flux may be 57.1 μWb.

[0067] For example, according to Example 2, when six wires (22) with a radius of 0.3 mm are arranged along the circumference of the magnet (21), the magnitude of the magnetic flux may be 57.4 μWb.

[0068] For example, according to Example 3, when four wires (22) with a radius of 0.3 mm are arranged along the circumference of the magnet (21), the magnitude of the magnetic flux may be 58.4 μWb.

[0069] For example, according to Example 4, when two wires (22) with a radius of 0.3 mm are placed along the circumference of the magnet (21), the magnitude of the magnetic flux may be 56.3 μWb.

[0070] For example, according to Example 5, when eight wires (22) with a radius of 0.1 mm are arranged along the circumference of the magnet (21), the magnitude of the magnetic flux may be 51.7 μWb.

[0071] For example, when the magnet (21) is placed alone without a plurality of wires (22) arranged to surround the magnet (21), the magnitude of the magnetic flux may be 27.4 μWb.

[0072] Magnet Radius (mm) Wire Radius (mm) Number of Wires Magnetic Flux Size Example 10.5 0.38 57.1 Example 20.5 0.36 57.4 Example 30.5 0.34 58.4 Example 40.5 0.32 56.3 Example 50.5 0.18 51.7 Magnet 0.5 -02 7.4

[0073] When a core unit is configured with only a magnet (21) without multiple wires (22), the value of the magnetic flux linkage generated can be reduced to half the level compared to the case of a core unit (20a, 20b, 20c) in which multiple wires (22) surround the magnet (21). According to this configuration, in a motor (100) according to one embodiment of the present disclosure, the magnetic flux linkage generated from the magnet (21) can be further concentrated in the axial direction of the motor (100) due to the multiple wires (22). Specific embodiments have been illustrated and described above. However, the invention is not limited to the above-described embodiments, and a person skilled in the art to which the invention belongs may make various modifications without departing from the gist of the technical concept of the invention as described in the following claims.

Claims

1. A rotor core comprising a first core receiving portion and a second core receiving portion arranged in the circumferential direction of a rotation axis; and A core assembly comprising a first core unit accommodated in the first core receiving portion and a second core unit accommodated in the second core receiving portion; The above core assembly is, A magnet extending in a direction parallel to the rotation axis direction of the rotor core; and A rotor comprising a plurality of wires extending in a direction parallel to the direction in which the magnet extends, and a plurality of wires arranged along the circumference of the magnet.

2. In Paragraph 1, The above core assembly is a rotor comprising a third core unit accommodated in the first core receiving portion.

3. In Paragraph 1, The plurality of wires above are rotors having a diameter smaller than the diameter of the magnet.

4. In Paragraph 1, The plurality of wires above are a rotor arranged radially around the magnet.

5. In Paragraph 1, The above plurality of wires is a rotor comprising ultra-low carbon steel.

6. In Paragraph 1, A rotor in which the length of the magnet is equal to or longer than the length of the plurality of wires.

7. In Paragraph 1, The above plurality of wires are a rotor that is bonded to the magnet by a non-conductive adhesive.

8. In Paragraph 1, A rotor in which each of the above plurality of wires is provided to be coated with an insulating material.

9. In Paragraph 1, The plurality of wires above are a rotor arranged to surround the magnet.

10. In Paragraph 1, A rotor in which the first core receiving portion and the second core receiving portion are arranged such that the cross-section perpendicular to the rotation axis of the rotor core has a polygonal shape.

11. In Paragraph 1, The above rotor core includes a shaft mounting portion on which a rotating shaft is mounted, and The first core receiving portion and the second core receiving portion are rotors provided along the outer circumference of the shaft mounting portion.

12. In Paragraph 11, A rotor further comprising a bearing provided between the shaft mounting portion and the rotating shaft.

13. In Paragraph 1, The rotor core above is a rotor comprising a partition for separating the first core receiving portion and the second core receiving portion.

14. Stator; A first rotor provided on a first side in the axial direction of the stator; A second rotor provided on the second side opposite to the first side in the axial direction of the stator; and A rotating shaft mounted on the first rotor and the second rotor; comprising The first rotor or the second rotor is, A rotor core comprising a shaft mounting portion to which the above-mentioned rotating shaft is rotatably coupled and a core receiving portion provided on the outer circumference of the above-mentioned shaft mounting portion; and A core assembly comprising a core unit accommodated in the core receiving portion; and The above core assembly is, A magnet extending in a direction parallel to the rotational axis direction of the rotor core; and A motor comprising a plurality of wires extending in a direction parallel to the direction in which the magnet extends, and a plurality of wires arranged along the circumference of the magnet.

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