Magnetic gear and magnetic-geared motor including same

Abstract

This magnetic-geared motor includes a magnetic gear. The magnetic gear includes: an inner rotor provided to receive rotational power; and an outer rotor disposed coaxially with the rotary shaft of the inner rotor and spaced apart from the inner rotor. In addition, the magnetic gear includes a pole piece disposed between the inner rotor and the outer rotor and spaced apart from the inner rotor and the outer rotor. The pole piece includes: a plurality of pole piece bodies arranged radially; and a plurality of bridges protruding from the plurality of pole piece bodies to connect neighboring pole piece bodies among the plurality of pole piece bodies. Each of the plurality of pole piece bodies includes: a through-hole formed therein; a recessed portion formed on the bottom surface thereof facing the inner rotor; and fillets formed on side surfaces facing the pole piece bodies adjacent to each other and connected to the plurality of bridges.

Description

Magnetic gear and magnetic geared motor including the same

[0001] The present disclosure relates to a magnetic gear including a pole piece and a magnetic geared motor including the same.

[0002] Magnetic gears are gear systems that transmit power using magnetic forces. Unlike traditional mechanical gears, magnetic gears can transmit power from the inner rotor to the outer rotor without physical contact. This results in less noise and vibration, and no wear due to gear interaction. Furthermore, the absence of mechanical friction reduces energy loss, enabling highly efficient operation. Recently, magnetic gears have been utilized across a wide range of industries, including wind turbines, electric vehicles, and home appliances.

[0003] A magnetic gear includes an inner rotor that receives power from a motor or the like, an outer rotor that is spaced apart from the inner rotor and receives power from the inner rotor through magnetic force, and a pole piece that is spaced apart from the inner rotor and the outer rotor between the inner and outer rotors. The pole piece serves to control and transmit the magnetic field between the inner and outer rotors.

[0004] One aspect of the present disclosure provides a magnetic gear capable of reducing torque ripple and a magnetic geared motor including the same.

[0005] One aspect of the present disclosure provides a magnetic gear capable of improving power density and a magnetic geared motor including the same.

[0006] The technical problems to be achieved in this document are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present invention belongs from the description below.

[0007] A magnetic gear according to the invention includes an inner rotor configured to receive rotational power. The magnetic gear includes an outer rotor arranged coaxially with a rotational axis of the inner rotor and spaced apart from the inner rotor. The magnetic gear includes a pole piece arranged between the inner rotor and the outer rotor and spaced apart from the inner rotor and the outer rotor. The pole piece includes a plurality of pole piece bodies arranged radially. The pole piece includes a plurality of bridges protruding from each of the plurality of pole piece bodies and connecting adjacent pole piece bodies among the plurality of pole piece bodies. Each of the plurality of pole piece bodies includes a through hole formed therein. Each of the plurality of pole piece bodies includes a recessed portion formed on a lower surface facing the inner rotor. Each of the plurality of pole piece bodies includes fillets formed on side surfaces facing adjacent pole piece bodies and connected to the plurality of bridges.

[0008] A magnetic geared motor according to the invention includes a motor. The magnetic geared motor includes an inner rotor connected to the rotational shaft and configured to be rotated by the motor. The magnetic geared motor includes an outer rotor that accommodates the inner rotor and is arranged to be spaced apart from the inner rotor. The magnetic geared motor includes a pole piece that is arranged between the inner rotor and the outer rotor and to be spaced apart from the inner rotor and the outer rotor. The pole piece includes a plurality of pole piece bodies arranged radially. The pole piece includes a plurality of bridges that protrude from each of the plurality of pole piece bodies and connect adjacent pole piece bodies among the plurality of pole piece bodies. Each of the plurality of pole piece bodies includes a through hole formed therein. Each of the plurality of pole piece bodies includes a recessed portion formed in a first body surface facing the inner rotor in a direction from the inner rotor toward the outer rotor. The plurality of pole piece bodies each include fillets formed on a second body surface facing adjacent pole piece bodies and connected to the plurality of bridges.

[0009] A magnetic gear according to the invention includes an inner rotor configured to rotate. The magnetic gear includes an outer rotor arranged to receive the inner rotor and spaced apart from the inner rotor. The magnetic gear includes a pole piece arranged between the inner rotor and the outer rotor and spaced apart from the inner rotor and the outer rotor. The pole piece includes a plurality of pole piece bodies arranged radially. The pole piece includes a plurality of bridges connecting adjacent pole piece bodies among the plurality of pole piece bodies. Each of the plurality of pole piece bodies includes a through hole. Each of the plurality of pole piece bodies includes recessed portions formed on one surface facing the inner rotor. Each of the plurality of pole piece bodies includes fillets formed on another surface facing the adjacent pole piece bodies.

[0010] FIG. 1 is a drawing illustrating a magnetic geared motor according to one embodiment.

[0011] Figure 2 is an exploded view of a magnetic geared motor according to one embodiment.

[0012] FIG. 3 is a front view of a magnetic geared motor according to one embodiment.

[0013] FIG. 4 is an enlarged view of a front portion of a magnetic geared motor according to one embodiment.

[0014] FIG. 5 is an enlarged view of a portion of the front of a magnetic geared motor according to one embodiment.

[0015] FIG. 6 is an enlarged view of a portion of the front of a magnetic geared motor according to one embodiment.

[0016] FIG. 7 is an enlarged view of a portion of the front of a magnetic geared motor according to one embodiment.

[0017] FIG. 8 is an enlarged view of a portion of the front of a magnetic geared motor according to one embodiment.

[0018] The embodiments described in this specification and the configurations illustrated in the drawings are merely preferred examples of the disclosed invention, and there may be various modified examples that can replace the embodiments and drawings of this specification at the time of filing of this application.

[0019] Additionally, the same reference numbers or symbols presented in each drawing of this specification represent parts or components that perform substantially the same function.

[0020] In addition, the terminology used in this specification is used to describe embodiments and is not intended to limit and / or restrict the disclosed invention. The singular expression includes plural expressions unless the context clearly indicates otherwise. In this specification, the terms "comprises" or "has" and the like are intended to specify the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0021] Additionally, terms including ordinal numbers such as “first,” “second,” etc. used herein may be used to describe various components, but the components are not limited by the terms, and the terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component. The term “and / or” includes any combination of a plurality of related listed items or any item among a plurality of related listed items.

[0022] Meanwhile, the shape and position of each component are not limited by the terms such as “front,” “back,” “left,” “right,” “upper,” and “lower” used in the description below.

[0023] When a component is said to be “connected,” “coupled,” “supported,” or “in contact with” another component, this includes not only cases where the components are directly connected, coupled, supported, or in contact, but also cases where the components are indirectly connected, coupled, supported, or in contact through a third component.

[0024] When we say that a component is "on" another component, this includes not only cases where the component is in contact with the other component, but also cases where there is another component between the two components.

[0025] When referring to the direction of rotation, clockwise may be referred to as the first direction, and counterclockwise, the direction opposite to the first direction, may be referred to as the second direction. While these expressions may be commonly used to describe specific details for implementing the invention, the rotational direction of the components of the present invention is not limited by these terms.

[0026] Hereinafter, a magnetic geared motor according to various embodiments will be specifically described with reference to the attached drawings.

[0027] FIG. 1 is a drawing illustrating a magnetic geared motor according to one embodiment. FIG. 2 is an exploded view of a magnetic geared motor according to one embodiment. FIG. 3 is a drawing illustrating a magnetic geared motor from the front according to one embodiment.

[0028] Referring to FIGS. 1 to 3, a magnetic geared motor (1) may include a rotating part (20). The rotating part (20) may include a motor (22). The rotating part (20) may include a shaft (21). The rotating part (20) may include an inner rotor coupling part (23).

[0029] The motor (22) can generate rotational power. One end of the shaft (21) can be coupled to the motor (22). The motor (22) can transmit rotational power to the shaft (21) to rotate the shaft (21). By receiving the rotational power of the motor (22), the shaft (21) can rotate around the rotational axis (R).

[0030] The shaft (21) may be arranged to extend in the first direction. The shaft (21) may have a shape of approximately a cylinder.

[0031] The inner rotor coupling (23) can be coupled to the other end of the shaft (21). When the motor (22) generates rotational power and the shaft (21) coupled with the motor (22) rotates, the inner rotor coupling (23) rotates along with the rotation of the shaft (21). The inner rotor coupling (23) can be inserted into the inner rotor opening (110) to transmit rotational power to the inner rotor (100, described later).

[0032] The magnetic geared motor (1) may include a magnetic gear (10).

[0033] The magnetic gear (10) may include an inner rotor (100). The inner rotor (100) may include an inner rotor body (140). The inner rotor body (140) may have a generally cylindrical shape. The inner rotor body (140) may be configured to extend in a first direction. The inner rotor body (140) may include a magnetic material.

[0034] The inner rotor body (140) may include an inner rotor opening (110). The inner rotor opening (110) may be formed to extend in a first direction inside the inner rotor body (140). The inner rotor coupling portion (23) of the rotating portion (20) may be inserted into the inner rotor opening (110) and coupled with the inner rotor (100). By coupling the inner rotor coupling portion (23) to the inner rotor opening (110), the inner rotor (100) may receive rotational power from the motor (22) and rotate.

[0035] When the inner rotor coupling part (23) is coupled to the inner rotor body (140), the shaft (21) can be arranged at the rotation center (G) of the inner rotor (100). That is, the rotation center (G) of the inner rotor (100) can be arranged on the rotation axis (R). Therefore, the inner rotor (100) can rotate around the rotation axis (R). Therefore, the rotation axis (R) can be the rotation axis (R) of the inner rotor (100).

[0036] The inner rotor coupling portion (23) can be joined to the inner rotor opening (110) by a force fit, but is not limited thereto and can be joined to the inner rotor (100) in various ways.

[0037] The inner rotor (100) may include an inner magnet (120). The inner magnet (120) may be coupled to the inner rotor body (140) along the outer circumferential surface of the inner rotor body (140). That is, the inner magnet (120) may be radially arranged on the outer circumferential surface of the inner rotor body (140) with the rotation axis (R) as the center. The inner magnet (120) may be arranged such that a magnet having an N pole on the outer circumferential surface of the inner rotor body (140) and a magnet having an S pole on the outer circumferential surface of the inner rotor body (140) are arranged at approximately equal intervals along the circumferential direction of the inner rotor body (140). One N pole magnet and one S pole magnet may form a pair of dipoles.

[0038] The inner magnet (120) may be arranged to cover the outer surface of the inner rotor body (140). The inner magnet (120) may be formed to extend along the first direction.

[0039] The magnetic gear (10) may include an outer rotor (300). The outer rotor (300) may include an outer rotor body (310). The outer rotor body (310) may have a generally cylindrical shape. The outer rotor body (310) may be configured to extend in a first direction. The outer rotor body (310) may include a magnetic material.

[0040] The outer rotor body (310) may include an outer rotor opening (330). The outer rotor opening (330) may be formed to extend in a first direction within the outer rotor body (310). The inner rotor (100) may be inserted into the outer rotor opening (330). The inner rotor (100) may be inserted into the outer rotor opening (330) so as to be spaced apart from the outer rotor (300). The center of the outer rotor (300) may be disposed on the rotational axis (R) of the inner rotor (100).

[0041] The outer rotor (300) may include an outer magnet (320). The outer magnet (320) may be coupled to the outer rotor body (310) along the inner circumferential surface of the outer rotor body (310). That is, the outer magnet (320) may be radially arranged on the inner circumferential surface of the outer rotor body (310) with the rotation axis (R) as the center. The outer magnet (320) may be arranged such that a magnet having an N pole on the inner circumferential surface of the outer rotor body (310) and a magnet having an S pole on the inner circumferential surface of the outer rotor body (310) are arranged at approximately equal intervals along the circumferential direction of the outer rotor body (310). One N pole magnet and one S pole magnet may form a pair of dipoles.

[0042] The outer magnet (320) may be arranged to cover the inner surface of the outer rotor body (310). The outer magnet (320) may be formed to extend along the first direction.

[0043] The magnetic gear (10) may include a pole piece (200).

[0044] The pole piece (200) may include a plurality of pole piece bodies (210). The plurality of pole piece bodies (210) may be arranged to extend in a first direction, respectively. The plurality of pole piece bodies (210) may be arranged radially. The plurality of pole piece bodies (210) may be arranged radially and spaced apart from each other at approximately equal intervals. The pole piece (200) may include a magnetic material.

[0045] A pole piece (200) may include a plurality of bridges (220). The plurality of bridges (220) may be provided to connect adjacent pole piece bodies (210) among the plurality of pole piece bodies (210). The plurality of bridges (220) may be provided to protrude from the pole piece bodies (210).

[0046] A plurality of bridges (220) may be arranged to protrude in a direction toward adjacent pole pieces (200). Each of the plurality of bridges (220) may be arranged to extend in a first direction. The plurality of pole piece bodies (210) are connected to each other by the plurality of bridges (220), so that the pole piece (200) may form an approximately cylindrical shape. Since the plurality of bridges (220) connect the plurality of pole piece bodies (210) to each other, the pole piece bodies (210) may be supported to each other to have a stronger supporting strength, and the accuracy of power transmission and gear ratio may be improved.

[0047] The pole piece body (210) and the plurality of bridges (220) can be formed integrally.

[0048] The pole piece (200) may include a pole piece opening (201). The pole piece opening (201) may extend in a first direction along the pole piece (200) and be formed on the inside of the pole piece (200).

[0049] The outer rotor (300) and the inner rotor (100) are arranged to be spaced apart from each other, and an internal space (S1) may be formed between the outer rotor (300) and the inner rotor (100). The pole piece (200) may be arranged to be inserted into the internal space (S1). When the pole piece (200) is inserted into the internal space (S1), the inner rotor (100) may be inserted into the pole piece opening (201).

[0050] The pole piece (200) can be positioned between the inner rotor (100) and the outer rotor (300) so as to be spaced apart from the inner rotor (100) and the outer rotor (300). Accordingly, the inner rotor (100), the pole piece (200), and the outer rotor (300) can be positioned so as not to contact each other.

[0051] The inner rotor (100) can receive the rotational power of the motor (22) and rotate in a first rotational direction based on the rotation center (G). When the inner rotor (100) rotates in the first rotational direction, the pole piece (200) is stationary, and the pole piece (200) can magnetically couple the inner magnet (120) of the inner rotor (100) and the outer magnet (320) of the outer rotor (300).

[0052] The number of pole piece bodies (210) can be calculated as follows, with the number of pairs of the inner rotor (100) and the number of pairs of the outer rotor (300) as variables.

[0053] [Mathematical Formula 1]

[0054] Ns = p1 - p2

[0055] Since the pole piece (200) magnetically couples the inner magnet (120) and the outer magnet (320), the pole piece (200) can generate spatial harmonics to magnetically transmit power from the inner rotor (100) to the outer rotor (300) with a constant gear ratio.

[0056] The gear ratio can have as variables the number of pairs of poles of the inner rotor (100) and the number of pairs of poles of the outer rotor (300). This can be calculated as follows using the rotational speed of the inner rotor (100) and the rotational speed of the outer rotor (300) as variables.

[0057] [Equation 2]

[0058] Gr = p2 / p1 = -(w1 / w2)

[0059] In conclusion, the outer rotor (300) can rotate by receiving magnetic power. When the inner rotor (100) rotates in the first rotational direction, the outer rotor (300) can rotate in a second rotational direction opposite to the first rotational direction with respect to the rotation center (G) by receiving magnetic power.

[0060] FIG. 4 is an enlarged view of a front portion of a magnetic geared motor according to one embodiment.

[0061] Referring to FIG. 4, a plurality of pole piece bodies (210) may include a bottom surface (213). The bottom surface (213) may be a surface of the pole piece body (210) facing the inner rotor (100). The bottom surface (213) may refer to a surface of the pole piece body (210) that is closest to the inner rotor (100). The bottom surface (213) may be defined as a first body surface (213) formed on the pole piece body (210).

[0062] The plurality of pole piece bodies (210) may include a side surface (212). The side surface (212) may refer to another side of the pole piece body (210) facing the adjacent pole piece bodies (210). The side surface (212) may be formed to extend from the bottom surface (213) toward the outer rotor (300) to form another side of the pole piece body (210). The side surface (212) may be defined as a second body surface (212) formed on the pole piece body (210).

[0063] The plurality of pole piece bodies (210) may include an upper surface (211). The upper surface (211) may be another surface of the pole piece body (210) facing the outer rotor (300). The upper surface (211) may mean another surface of the pole piece body (210) that is closest to the outer rotor (300). The upper surface (211) may extend from a portion of the side surface (212) that is closest to the outer rotor (300) to form another surface of the pole piece body (210). The upper surface (211) may be defined as a third body surface (211) formed on the pole piece body (210).

[0064] Each of the plurality of pole piece bodies (210) may include a through hole (215) formed therein.

[0065] The through hole (215) can be formed in the pole piece body (210) in a direction parallel to the rotation axis (R). The through hole (215) can be formed to extend along the first direction in which the pole piece body (210) extends and penetrate the pole piece body (210).

[0066] The through holes (215) may be formed in a plurality of numbers. The through holes (215) may include a first through hole (215a) formed on one side of the pole piece body (210). The through holes (215) may include a second through hole (215b) formed on the opposite side of the first through hole (215a) with respect to the recessed portion (214). That is, the through holes (215) may be formed symmetrically with respect to the pole piece body (210) with respect to the recessed portion (214). Although the number of through holes (215) formed in each pole piece body (210) is illustrated as two in the drawing, the number of through holes (215) formed in each pole piece body (210) is not limited thereto.

[0067] The through hole (215) may be provided with a specific magnetic permeability of 1.1 or less. More specifically, the pole piece (200) serves to magnetically couple the inner rotor (100) and the outer rotor (300), and the through hole (215) may be provided with a specific magnetic permeability of 1.1 or less to control the passage of magnetic flux through the pole piece (200).

[0068] As the through hole (215) is formed in the pole piece body (210), the harmonics of the air gap magnetic flux density that do not contribute to the torque transmission from the inner rotor (100) to the outer rotor (300) can be improved. Through this, the torque ripple resulting from the power transmission from the magnetic gear (10) to the outer rotor (300) can be improved.

[0069] The pole piece body (210) may include a recess (214).

[0070] The recessed portion (214) may be formed on the bottom surface (213) of the pole piece body (210) facing the inner rotor (100). The recessed portion (214) may be formed in the center of the bottom surface (213) of the pole piece body (210). The recessed portion (214) may be formed by recessing in the direction from the inner rotor (100) toward the outer rotor (300).

[0071] The recessed portion (214) may be formed in the pole piece body (210) so as to extend in the first direction. The shape in which the recessed portion (214) extends by being recessed may be approximately in the shape of a square pillar, but is not limited thereto.

[0072] As a depression (214) is formed on the bottom surface (213) of the pole piece body (210), harmonics of the air gap flux density that do not contribute to the torque transmission from the inner rotor (100) to the outer rotor (300) can be improved. Through this, torque ripple resulting from the power transmission from the magnetic gear (10) to the outer rotor (300) can be improved.

[0073] The pole piece (200) may include a plurality of bridges (220). The plurality of bridges (220) may be formed to protrude from a side surface (212) of the pole piece body (210). The plurality of bridges (220) may include a first bridge surface (222) facing the inner rotor (100). The plurality of bridges (220) may include a second bridge surface (221) facing the outer rotor (300).

[0074] The pole piece body (210) may include fillets (216, 217). The fillets (216, 217) may be formed on the side surface (212) of the pole piece body (210) facing the adjacent pole piece bodies (210). That is, the fillets (216, 217) may be formed on the side surfaces (212) of the pole piece body (210) and provided in plurality. The plurality of fillets (216, 217) may be connected to a plurality of bridges (220).

[0075] That is, a plurality of fillets (216, 217) may be formed on the side where the pole piece body (210) and the plurality of bridges (220) are joined, and may be formed to extend from the side surface (212) of the pole piece body (210) to one side (221) of the plurality of bridges (220) facing the outer rotor (300).

[0076] The fillet (216) may be formed in a concave shape toward the outer rotor (300) on the side (212) of the pole piece body (210) and the side where the plurality of bridges (220) are coupled. One surface (221) of the plurality of bridges (220) may refer to a second bridge surface (221). The plurality of fillets (216) may include a magnetic material, like the plurality of pole piece bodies (210).

[0077] Since a plurality of fillets (216, 217) are added to the connection portion between the plurality of pole piece bodies (210) and the plurality of bridges (220), a magnetic material can be filled in the space where the plurality of fillets (216, 217) are formed. If there are no plurality of fillets (216, 217), the space is filled with air or the like, but since the space is filled with a magnetic material having a higher magnetic permeability than air, more magnetic flux can flow in the pole piece (200). As the magnetic flux flowing in the pole piece (200) increases, the transmission torque transmitted to the outer rotor (300) by the rotation of the inner rotor (100) can increase.

[0078] As described above, a through hole (215), a depression (214), and fillets (216, 217) can be formed in the pole piece (200). Accordingly, the loss of eddy current generated in the inner rotor body (140) and the outer rotor body (310) and the loss of eddy current generated in the inner magnet (120) and the outer magnet (320) can be reduced.

[0079] The first bridge faces (222) of the plurality of bridges (220) may be arranged so as not to form a step with the bottom face (213) of the pole piece body (210). That is, the plurality of bridges (220) may be formed to protrude from a portion of the side face (212) of the pole piece body (210) adjacent to the inner rotor (100), so that the first bridge faces (222) of the plurality of bridges (220) extend from the bottom face (213) of the pole piece body (210).

[0080] The second bridge surface (221) of the plurality of bridges (220) may be formed to be bent with the side surface (212) of the pole piece body (210). Fillets (216, 217) may be positioned at the corresponding bending portion.

[0081] The magnetic gear (10) may include an internal space (S1). The internal space (S1) may be a cavity formed by the inner rotor (100) and the outer rotor (300) being separated from each other. More specifically, the internal space (S1) may be a space formed by being surrounded by the inner magnet (120) of the inner rotor (100) and the outer rotor body (310) of the outer rotor (300).

[0082] The inner space (S1) may include a bottom space (S2) of the pole piece (200). The bottom space (S2) of the pole piece (200) may refer to a space between the pole piece (200) and the inner rotor (100). More specifically, the bottom space (S2) of the pole piece (200) may refer to a space formed by a first bridge surface (222) of the bridge (220) and an inner magnet (120) of the inner rotor (100) being spaced apart from each other. In addition, the bottom space (S2) of the pole piece (200) may refer to a space formed by a bottom surface (213) of the pole piece body (210) and an inner magnet (120) of the inner rotor (100) being spaced apart from each other.

[0083] The lower space (S2) of the pole piece (200) can be formed wider by the recess (214) on the lower side of the pole piece body (210) than on the lower side of the first bridge surface (222).

[0084] The internal space (S1) may include a space (S3) above the pole piece (200). The space (S3) above the pole piece (200) may refer to a space between the pole piece (200) and the outer rotor (300). More specifically, the space (S3) above the pole piece (200) may refer to a space formed by the upper surface (211) of the pole piece body (210) and the outer magnet (320) of the outer rotor (300) being spaced apart from each other.

[0085] As described above, the pole piece (200) can be placed in the internal space (S1) and spaced apart from both the inner rotor (100) and the outer rotor (300).

[0086] FIG. 5 is an enlarged view of a portion of the front of a magnetic geared motor according to one embodiment. Descriptions of any content that overlaps with the above will be omitted below.

[0087] Referring to FIG. 5, the through hole (415) may include a slit shape.

[0088] The slit shape may be formed in the pole piece body (410) so as to extend in a direction from the inner rotor (100) toward the outer rotor (300). That is, the length in the direction from the inner rotor (100) toward the outer rotor (300) may be longer than the length in the radial direction formed by the plurality of bridges (420).

[0089] The length of the slit in the direction from the inner rotor (100) toward the outer rotor (300) can be set to be greater than the depth of the recessed portion (414).

[0090] The length of the slit from the inner rotor (100) toward the outer rotor (300) can be made larger than the thickness of the plurality of bridges (420).

[0091] In the city, it is shown that there are two slit-shaped penetration holes (415), but the number is not limited to this.

[0092] When the through hole (415) is in the form of a slit, the specific magnetic permeability in the through hole can be set to 1.1 or less due to the slit shape. Through this, the through hole (415) is set to have a specific magnetic permeability of 1.1 or less, so that the passage of magnetic flux in the pole piece (400) can be controlled. Even when the through hole (415) is in the form of a slit, the harmonics of the gap magnetic flux density that do not contribute to the torque transmission from the inner rotor (100) to the outer rotor (300) can be improved, so that the torque ripple due to the power transmission from the magnetic gear (40) to the outer rotor (300) can be improved.

[0093] FIG. 6 is an enlarged view of a portion of the front of a magnetic geared motor according to one embodiment.

[0094] Referring to FIG. 6, the depth of the recessed portion (514) can be formed to be greater than the thickness of the plurality of bridges (520).

[0095] As the depth of the recess (514) becomes deeper, the degree of harmonic improvement of the air gap flux density that does not contribute to the torque of the magnetic gear (50) can be adjusted. The torque ripple can be arranged to be reduced according to the harmonic improvement of the air gap flux density.

[0096] FIG. 7 is an enlarged view of a portion of the front of a magnetic geared motor according to one embodiment.

[0097] Referring to FIG. 7, a plurality of bridges (720) may be formed to protrude from a position between the lower surface (713) and the upper surface (711) of the side surface (712) of the pole piece body (710). A plurality of bridges (720) may be formed to protrude from the center of the side surface (712) of the pole piece body (710).

[0098] The plurality of bridges (720) may include a first bridge surface (722) facing the inner rotor (100) and a second bridge surface (721) facing the outer rotor (300). Since the plurality of bridges (720) protrude from the side surface (712) between the bottom surface (713) and the top surface (711), the portion where the plurality of bridges (720) and the side surface (712) of the pole piece body (710) are bent may be formed at the bottom and the top based on the plurality of bridges (720).

[0099] The fillets (716, 717) may include a first fillet (716b, 717b) extending to a first bridge face (722). The first fillet (716b, 717b) may be formed at a lower portion based on the plurality of bridges (720) and may extend to a side face (712). The first fillet (716b, 717b) may be formed to extend from the side face (712) to the first bridge face (722). The first fillet (716b, 717b) may include a concave shape in a direction toward the inner rotor (100).

[0100] The fillets (716, 717) may include a second fillet (716a, 717a) extending to a second bridge face (721). The second fillet (716a, 717a) may be formed above the plurality of bridges (720) and may extend to the side face (712). The second fillet (716a, 717a) may be formed to extend from the side face (712) to the second bridge face (721). The second fillet (716a, 717a) may include a concave shape in a direction toward the outer rotor (300).

[0101] The first fillet (716b, 717b) and the second fillet (716a, 717a) may have a shape that is symmetrical to each other based on the plurality of bridges (720).

[0102] Since fillets (716, 717) are formed on both the bottom and the top based on the plurality of bridges (720), the space in which the plurality of fillets (716, 717) are formed can be filled with a magnetic material. If there are no fillets (716, 717), the space is filled with air or the like, but since the space is filled with a magnetic material having a higher magnetic permeability than air, more magnetic flux can flow in the pole piece (700). As the magnetic flux flowing in the pole piece (700) increases, the transmission torque transmitted to the outer rotor (300) by the rotation of the inner rotor (100) can increase.

[0103] The internal space (S1) may include a first internal space (S4). The first internal space (S4) may refer to a space formed between the second bridge surface (721) and the outer magnet (320). The first internal space (S4) may be provided to be larger than the upper space of the pole piece (700).

[0104] The inner space (S1) may include a second inner space (S5). The second inner space (S5) may refer to a space formed between the first bridge surface (722) and the inner magnet (120). The first inner space (S4) may be provided to be larger than the upper space of the pole piece (700).

[0105] The first internal space (S4) and the second internal space (S5) may have corresponding sizes.

[0106] FIG. 8 is an enlarged view of a portion of the front of a magnetic geared motor according to one embodiment.

[0107] Referring to FIG. 8, one surface (821) of the plurality of bridges (820) may be formed so as not to form a step with the upper surface (811) of the pole piece body (810). That is, the plurality of bridges (820) may be formed so as to protrude from a portion of the side surface (812) of the pole piece body (810) adjacent to the outer rotor (300) so that one surface (821) of the plurality of bridges (820) extends from the upper surface (811) of the pole piece body (810). The above-mentioned one surface (821) may refer to the second bridge surface (821). Therefore, the recessed portion (814) may be formed closer to the inner rotor (100) than the bridge surface (821).

[0108] The first bridge surface (822) of the plurality of bridges (820) may be formed to be bent with the side surface (812) of the pole piece body (810). The fillets (816, 817) may be positioned at the corresponding bend.

[0109] A magnetic gear (10) according to one embodiment includes an inner rotor (100) configured to receive rotational power. The magnetic gear (10) includes an outer rotor (300) arranged coaxially with a rotational axis (R) of the inner rotor (100) and spaced apart from the inner rotor (100). The magnetic gear (10) includes a pole piece (200) arranged between the inner rotor (100) and the outer rotor (300) and spaced apart from the inner rotor (100) and the outer rotor (300). The pole piece (200) includes a plurality of pole piece bodies (210) arranged radially. The above pole piece (200) includes a plurality of bridges (220) that protrude from each of the plurality of pole piece bodies (210) and connect adjacent pole piece bodies (210) among the plurality of pole piece bodies (210). Each of the plurality of pole piece bodies (210) includes a through hole (215) formed therein. Each of the plurality of pole piece bodies (210) includes a recessed portion (214) formed on a bottom surface (213) facing the inner rotor (100). Each of the plurality of pole piece bodies (210) includes fillets (216, 217) formed on side surfaces (212) facing adjacent pole piece bodies (210) and connected to the plurality of bridges (220).

[0110] The above-mentioned recessed portion (214) can be recessed in the direction from the inner rotor (100) toward the outer rotor (300).

[0111] The above plurality of bridges (220) can be formed by protruding from the side surfaces (212).

[0112] The above plurality of bridges (220) may each include a first bridge surface (222) facing the inner rotor (100) and provided so as not to form a step with the bottom surface (213).

[0113] The above through hole (215) can be formed in the pole piece body (210) in a direction parallel to the rotation axis (R).

[0114] The above through hole (215) may include a first through hole (215a) formed on one side of the pole piece body (210) and a second through hole (215b) formed on the opposite side of the first through hole (215a) based on the recessed portion (214).

[0115] The above through hole (415) may include a slit shape.

[0116] The above through hole (215) can be provided with a specific investment ratio of 1.1 or less.

[0117] The depth of the above-mentioned recessed portion (514) may be formed to be greater than the thickness of the plurality of bridges (520).

[0118] The plurality of bridges (220) may each further include a second bridge face (221) facing the outer rotor (300). The fillets (216, 217) may be formed to extend from the side surface (212) to the second bridge face (221).

[0119] The above pole piece body (710) further includes an upper surface (711) facing the outer rotor (300), and the plurality of bridges (720) can be formed to protrude between the lower surface (713) and the upper surface (711).

[0120] Each of the plurality of bridges (720) may include a first bridge surface (722) facing the inner rotor (100) and a second bridge surface (721) facing the outer rotor (300). The fillets (716, 717) may include a first fillet (716b, 717b) formed to extend from the side surface (712) to the first bridge surface (722) and a second fillet (716a, 717a) formed to extend from the side surface (712) to the second bridge surface (721).

[0121] The above plurality of bridges (820) may include a surface (821) of the bridge (820) facing the outer rotor (300). The pole piece body (810) may include an upper surface (811) facing the outer rotor (300). The surface (820) of the bridge (820) may be arranged so as not to form a step with the upper surface (811).

[0122] The above-mentioned recessed portion (814) may be formed closer to the inner rotor (100) than one surface of the bridge (820).

[0123] A magnetic geared motor (1) according to one embodiment includes a motor (22). The magnetic geared motor (1) includes an inner rotor (100) connected to the rotational shaft (R) and arranged to be rotated by the motor (22). The magnetic geared motor (1) includes an outer rotor (300) that accommodates the inner rotor (100) and is arranged to be spaced apart from the inner rotor (100). The magnetic geared motor (1) includes a pole piece (200) that is arranged between the inner rotor (100) and the outer rotor (300) to be spaced apart from the inner rotor (100) and the outer rotor (300). The pole piece (200) includes a plurality of pole piece bodies (210) that are arranged radially. The above pole piece (200) includes a plurality of bridges (220) that protrude from each of the plurality of pole piece bodies (210) and connect adjacent pole piece bodies (210) among the plurality of pole piece bodies (210). Each of the plurality of pole piece bodies (210) includes a through hole (215) formed therein. Each of the plurality of pole piece bodies (210) includes a recessed portion (214) formed in a direction from the inner rotor (100) toward the outer rotor (300) on a first body surface (213) facing the inner rotor (100). Each of the plurality of pole piece bodies (210) includes fillets (216, 217) that are formed on a second body surface (212) facing adjacent pole piece bodies (210) and are connected to the plurality of bridges (220).

[0124] The above plurality of bridges (220) may each be formed by protruding from the second body surface (212).

[0125] The above plurality of bridges (220) may each include a first bridge surface (222) facing the inner rotor (100) and provided so as not to form a step with the first body surface (213).

[0126] The above-mentioned pole piece body (710) further includes a third body surface (711) facing the outer rotor (300), and the plurality of bridges (720) can be formed to protrude between the first body surface (713) and the third body surface (711).

[0127] The above plurality of bridges (820) may each include a surface of the bridge (820) facing the outer rotor (300). The pole piece body (810) may include an upper surface (811) facing the outer rotor (300). One surface of the bridge (820) may be provided so as not to form a step with the upper surface (811).

[0128] A magnetic gear (10) according to one embodiment includes an inner rotor (100) that is arranged to rotate. The magnetic gear (10) includes an outer rotor (300) that is arranged to receive the inner rotor (100) and is spaced apart from the inner rotor (100). The magnetic gear (10) includes a pole piece (200) that is arranged between the inner rotor (100) and the outer rotor (300) and is spaced apart from the inner rotor (100) and the outer rotor (300). The pole piece (200) includes a plurality of pole piece bodies (210) that are arranged radially. The pole piece (200) includes a plurality of bridges (220) that connect adjacent pole piece bodies (210) among the plurality of pole piece bodies (210). Each of the plurality of pole piece bodies (210) includes a through hole (215). Each of the plurality of pole piece bodies (210) includes recessed portions (214) formed on one surface facing the inner rotor (100). Each of the plurality of pole piece bodies (210) includes fillets (216, 217) formed on the other surface facing the adjacent pole piece bodies (210).

[0129] According to the invention of the present invention, by forming a through hole and a depression in a pole piece, the harmonics of the gap magnetic flux density that do not contribute to the torque of the magnetic gear can be improved, thereby reducing torque ripple.

[0130] According to the invention, a fillet is formed and a portion having an investment rate of air can be filled with a pole piece material, thereby increasing the torque transmitted to the outer rotor as more magnetic flux flows, thereby improving the power density.

[0131] The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and other effects that are not mentioned can be clearly understood by a person having ordinary skill in the art to which the present disclosure belongs from the description below.

[0132] The above illustrates and describes specific embodiments. However, the invention is not limited to the above-described embodiments, and those skilled in the art will readily appreciate that various modifications and implementations can be made without departing from the spirit and scope of the invention as set forth in the claims below.

Claims

1. An inner rotor provided to receive rotational power; An outer rotor arranged coaxially with the rotational axis of the inner rotor and spaced apart from the inner rotor; and A pole piece is disposed between the inner rotor and the outer rotor so as to be spaced apart from the inner rotor and the outer rotor; The above Paul Peace, a plurality of radially arranged pole piece bodies; and A plurality of bridges protruding from each of the plurality of pole piece bodies and connecting adjacent pole piece bodies among the plurality of pole piece bodies; Each of the above plurality of pole piece bodies, A perforation formed inside; A depression formed on the lower surface facing the inner rotor; and A magnetic gear comprising fillets formed on side surfaces facing adjacent pole piece bodies and connected to the plurality of bridges; 2. In paragraph 1, The above-mentioned recessed portion is a magnetic gear that recesses in a direction from the inner rotor toward the outer rotor.

3. In paragraph 1, A magnetic gear in which the above plurality of bridges are formed by protruding from the side surfaces, respectively.

4. In paragraph 1, A magnetic gear wherein the plurality of bridges each include a first bridge surface facing the inner rotor and formed so as not to form a step with the bottom surface.

5. In paragraph 1, The above through hole is a magnetic gear formed in the pole piece body in a direction parallel to the rotation axis.

6. In paragraph 5, The above through hole is, A first through hole formed on one side of the above-mentioned pole piece body, and A magnetic gear including a second through hole formed on the opposite side of the first through hole based on the above-mentioned recessed portion.

7. In paragraph 1, The above through hole is a magnetic gear including a slit shape.

8. In paragraph 1, The above through hole is a magnetic gear having a specific permeability of 1.1 or less.

9. In paragraph 1, A magnetic gear in which the depth of the above-mentioned recessed portion is formed to be greater than the thickness of the plurality of bridges.

10. In paragraph 4, The above plurality of bridges each further include a second bridge face facing the outer rotor, A magnetic gear in which the above fillets are formed to extend from the side surface to the second bridge surface.

11. In paragraph 3, The above pole piece body further includes an upper surface facing the outer rotor, The above plurality of bridges are magnetic gears formed to protrude between the lower surface and the upper surface.

12. In paragraph 11, Each of the above multiple bridges, The first bridge face facing the inner rotor and comprising a second bridge face facing the outer rotor; The above fillets are, A first fillet formed to extend from the above side to the first bridge surface, and A magnetic gear comprising a second fillet formed to extend from the side surface to the second bridge surface.

13. In paragraph 1, The above plurality of bridges include one side of the bridge facing the outer rotor, The above pole piece body includes an upper surface facing the outer rotor, A magnetic gear in which one side of the above bridge is designed so as not to form a step with the upper surface.

14. In paragraph 13, A magnetic gear in which the above-mentioned recessed portion is formed closer to the inner rotor than one surface of the above-mentioned bridge.

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