Rotor and motor having the same

Abstract

An embodiment discloses a motor comprising a stator; a rotor formed of a plurality of unit rotors; and a shaft coupled to the rotor, wherein the unit rotor comprises a rotor core coupled to the shaft, a plurality of magnets disposed on the outer side of the rotor core, and a can disposed to cover the magnets, and the can comprises a pipe-shaped body and a plate portion extending radially from only one end of the body. Accordingly, the motor can improve productivity by eliminating bonding and curing processes during the assembly process by manufacturing and providing a unit rotor in which the rotor core, magnets, and can are pre-coupled.

Description

Technology Field

[0001] The embodiment relates to a rotor and a motor including the same. Background Technology

[0002] A motor is a device that converts electrical energy into mechanical energy to generate rotational force, and it is widely used in vehicles, household electronic appliances, industrial equipment, and the like. In particular, the motor can be used in devices to ensure steering stability in automobiles. For instance, the motor can be used in vehicle motors such as Electronic Power Steering Systems (EPS).

[0003] The motor may include a housing, a shaft, a stator disposed on the inner circumference of the housing, and a rotor installed on the outer circumference of the shaft. Here, the stator induces electrical interaction with the rotor to induce rotation of the rotor. Additionally, the rotor may be formed by arranging a plurality of unit rotors in the axial direction.

[0004] The above unit rotor may include a rotor core and a plurality of magnets disposed on the rotor core. Depending on the placement position of the magnets, the rotor may be classified into an IPM (Internal Permanent Magnet) type rotor in which magnets are inserted and disposed inside the rotor core, and an SPM (Surface Permanent Magnet) type rotor in which magnets are attached to the surface of the rotor core.

[0005] In the case of the above-mentioned SPM type rotor, a magnet is attached to the rotor core using an adhesive due to structural characteristics. Additionally, a can may be applied to improve the assembly durability between the magnet and the rotor core.

[0006] The above-mentioned can can serve to protect the rotor and prevent the magnet from detaching. At this time, the can can be fixed to the rotor core where the magnet is placed by applying an adhesive material to the inner side of the can.

[0007] However, there is a problem in that the number of process steps increases due to the bonding process of applying the adhesive twice (a bonding process for joining the rotor core and the magnet, and a bonding process for applying the adhesive to the inside of the can).

[0008] Furthermore, since the bonding process involves a curing process of the adhesive member, there is a problem of increased production time. Moreover, this problem acts as a factor that lowers the productivity of the motor.

[0009] Therefore, there is a need for a rotor and a motor including the same that can improve productivity by unifying the above-mentioned unit rotor and reducing production time associated with the bonding and curing processes. The problem to be solved

[0010] The embodiment provides a rotor formed using a plurality of unified unit rotors and a motor including the same.

[0011] The embodiment provides a rotor and a motor including the same that improve productivity by eliminating bonding and curing processes during the assembly process by using a unit rotor in which a rotor core, a magnet, and a can are pre-combined.

[0012] The problems that the embodiments aim to solve are not limited to those mentioned above, and other problems not mentioned herein will be clearly understood by those skilled in the art from the description below. means of solving the problem

[0013] The above problem is achieved by a motor comprising a stator; a rotor formed of a plurality of unit rotors; and a shaft coupled to the rotor, wherein the unit rotor comprises a rotor core coupled to the shaft, a plurality of magnets disposed on the outer side of the rotor core, and a can disposed to cover the magnets, and the can comprises a pipe-shaped body and a plate portion extending radially from only one end of the body.

[0014] Here, with respect to the lower surface of the rotor core, the axial length (L3) of the body may be smaller than the axial length (L1) of the rotor core and larger than the axial length (L2) of the magnet. Also, the thickness (t) of the can may be smaller than the difference (L1-L2) between the axial length (L1) of the rotor core and the axial length (L2) of the magnet.

[0015] In addition, a plate portion of one of the adjacent unit rotors may be disposed between the magnet of one unit rotor and the magnet of another unit rotor disposed adjacently in the axial direction.

[0016] In addition, when a plate portion of one of the adjacent unit rotors is positioned between the magnet of one unit rotor and the magnet of another unit rotor positioned adjacently in the axial direction, the plate portion of one of the unit rotors can be formed to have a predetermined spacing (G) from the magnet of the other unit rotor.

[0017] In addition, the magnet of any one of the unit rotors arranged adjacently in the axial direction can come into contact with the magnet of another unit rotor.

[0018] Meanwhile, the rotor core includes a rotor core body and a guide protruding radially from the outer surface of the rotor core body, and the outer surface of the guide may come into contact with the inner surface of the plate portion.

[0019] In addition, the plate portion and the axial surface of the magnet disposed on one of the above-mentioned unit rotors can come into contact with each other.

[0020] The above problem is achieved by a motor comprising: a stator; a rotor positioned corresponding to the stator; and a shaft coupled to the rotor, wherein the rotor comprises a first unit rotor, a second unit rotor positioned below the first unit rotor, and a third unit rotor positioned below the second unit rotor, and each of the first unit rotor, the second unit rotor, and the third unit rotor comprises a rotor core coupled to the shaft, a plurality of magnets positioned outside the rotor core, and a can positioned to cover the magnets, wherein the can comprises a pipe-shaped body and a plate portion extending radially from only one end of the body, and the plate portion of the can positioned on the second unit rotor is positioned to face the lower surface of the magnet positioned on the first unit rotor, and the lower surface of the magnet positioned on the second unit rotor is positioned to face the upper surface of the magnet positioned on the third unit rotor.

[0021] Here, an axial space is formed between the lower surface of the magnet disposed in the first unit rotor and the plate portion of the can disposed in the second unit rotor, and the lower surface of the magnet disposed in the second unit rotor and the upper surface of the magnet disposed in the third unit rotor can come into contact with each other.

[0022] The above problem is achieved by a plurality of unit rotors arranged axially, wherein the unit rotor comprises a rotor core, a plurality of magnets arranged along the outer surface of the rotor core, and a can arranged to cover the magnets, wherein the can comprises a pipe-shaped body and a plate portion extending radially from only one end of the body, and wherein, in one of the unit rotors, one axial surface of the magnet contacts the plate portion, and the other axial surface is exposed from the can. Effects of the invention

[0023] The embodiment can improve productivity by using a plurality of unified unit rotors. Specifically, by manufacturing and providing a unit rotor in which a rotor core, a magnet, and a can are pre-assembled, the bonding and curing processes can be eliminated during the motor assembly process. Accordingly, the productivity of the motor can be improved.

[0024] The various and beneficial advantages and effects of the embodiments are not limited to those described above and may be more easily understood in the process of explaining specific embodiments. Brief explanation of the drawing

[0025] FIG. 1 is a drawing showing a motor according to an embodiment, and FIG. 2 is a perspective view showing a rotor and a shaft disposed in a motor according to an embodiment, and FIG. 3 is an exploded perspective view showing a rotor and a shaft disposed in a motor according to an embodiment, and FIG. 4 is a bottom exploded perspective view showing a rotor and a shaft disposed in a motor according to an embodiment, and FIG. 5 is a cross-sectional view showing a rotor and a shaft disposed in a motor according to an embodiment, and FIG. 6 is a perspective view showing a unit rotor of a rotor disposed in a motor according to an embodiment, and FIG. 7 is an exploded perspective view showing a unit rotor of a rotor disposed in a motor according to an embodiment, and FIG. 8 is a cross-sectional view showing a unit rotor of a rotor placed in a motor according to an embodiment. Specific details for implementing the invention

[0026] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

[0027] However, the technical concept of the present invention is not limited to some of the described embodiments but can be implemented in various different forms, and within the scope of the technical concept of the present invention, one or more of the components among the embodiments may be selectively combined or substituted.

[0028] In addition, terms used in the embodiments of the present invention (including technical and scientific terms) may be interpreted in a sense that is generally understood by those skilled in the art to which the present invention belongs, unless explicitly and specifically defined otherwise. Terms that are commonly used, such as terms defined in advance, may be interpreted in consideration of their meaning in the context of the relevant technology.

[0029] Furthermore, the terms used in the embodiments of the present invention are for the purpose of describing the embodiments and are not intended to limit the present invention.

[0030] In this specification, the singular form may include the plural form unless specifically stated otherwise in the text, and when described as "at least one of A and B and C (or more than one)," it may include one or more of all combinations that can be formed from A, B, and C.

[0031] In addition, terms such as first, second, A, B, (a), (b), etc. may be used when describing the components of the embodiments of the present invention.

[0032] These terms are intended merely to distinguish a component from other components and are not limited by the nature, order, sequence, etc., of the said component.

[0033] And, where it is stated that a component is 'connected', 'combined', or 'joined' to another component, this may include not only cases where the component is directly connected, combined, or joined to the other component, but also cases where it is 'connected', 'combined', or 'joined' due to another component located between the component and the other component.

[0034] Furthermore, when described as being formed or placed "above or below" each component, "above" or "below" includes not only cases where two components are in direct contact with each other, but also cases where one or more other components are formed or placed between the two components. Additionally, when expressed as "above or below," it may include the meaning of a downward direction as well as an upward direction relative to a single component.

[0035] Hereinafter, embodiments will be described in detail with reference to the attached drawings, provided that identical or corresponding components are given the same reference number regardless of the drawing symbols, and redundant descriptions thereof will be omitted.

[0036] FIG. 1 is a drawing showing a motor according to an embodiment, FIG. 2 is a perspective view showing a rotor and a shaft disposed in a motor according to an embodiment, FIG. 3 is an exploded perspective view showing a rotor and a shaft disposed in a motor according to an embodiment, FIG. 4 is a bottom exploded perspective view showing a rotor and a shaft disposed in a motor according to an embodiment, and FIG. 5 is a cross-sectional view showing a rotor and a shaft disposed in a motor according to an embodiment. In FIG. 1 and FIG. 3, the x direction may mean the radial direction, and the y direction may mean the axial direction. Also, the axial direction and the radial direction may be perpendicular to each other. Here, the axial direction may be the longitudinal direction of the shaft (500). Also, the reference numeral 'C' may indicate the center of rotation of the motor.

[0037] Referring to FIG. 1, a motor according to an embodiment may include a housing (100) having an opening formed on one side, a cover (200) disposed on the upper part of the housing (100), a stator (300) disposed inside the housing (100), a rotor (400) disposed inside the stator (300), and a shaft (500) coupled to the rotor (400). Here, the term "inside" refers to a direction disposed toward the rotation center (C) of the motor with respect to the radial direction, and the term "outside" may refer to a direction opposite to the inside.

[0038] Additionally, the motor may include a bus bar (600) positioned on the upper side of the stator (300) and a sensor unit (700) that detects the rotation of the rotor (400).

[0039] The housing (100) and the cover (200) can form the external shape of the motor. Additionally, an internal receiving space can be formed by combining the housing (100) and the cover (200). Accordingly, a stator (300), a rotor (400), a shaft (500), a bus bar (600), and a sensor unit (700), etc., can be arranged in the receiving space.

[0040] At this time, the shaft (500) is rotatably positioned in the receiving space. Accordingly, the motor may further include bearings (B) positioned at the upper and lower portions of the shaft (500), respectively. Here, the bearing (B) positioned in the housing (100) may be called the first bearing, housing bearing, or lower bearing. And, the bearing (B) positioned in the cover (200) may be called the second bearing, cover bearing, or upper bearing.

[0041] The above housing (100) may be formed in a cylindrical shape. The housing (100) may accommodate a stator (300), a rotor (400), etc. inside. At this time, the shape or material of the housing (100) may be varied. For example, the housing (100) may be formed of a metal material that can withstand high temperatures.

[0042] The housing (100) may include a pocket portion at the bottom capable of accommodating a bearing (B). Here, the pocket portion of the housing (100) may be referred to as a housing pocket portion.

[0043] The cover (200) can be placed on the opening surface of the housing (100), that is, on the upper part of the housing (100), to cover the opening of the housing (100).

[0044] And, the cover (200) may include a pocket portion capable of accommodating a bearing (B). Here, the pocket portion of the cover (200) may be called a cover pocket portion.

[0045] The stator (300) induces electrical interaction with the rotor (400) to induce rotation of the rotor (400).

[0046] The stator (300) may be positioned inside the housing (100). At this time, the stator (300) may be supported on the inner circumference of the housing (100). Additionally, the stator (300) may be positioned outside the rotor (400). That is, the rotor (400) may be rotatably positioned inside the stator (300).

[0047] Referring to FIG. 1, the stator (300) may include a stator core (310), an insulator (320) placed on the stator core (310), and a coil (330) wound on the insulator (320).

[0048] A coil (330) that forms a rotating magnetic field may be wound on the stator core (310). Here, the stator core (310) may be formed as a single core or formed by combining multiple divided cores.

[0049] The stator core (310) may be formed by stacking multiple plates in the form of thin steel plates, but is not necessarily limited thereto. For example, the stator core (310) may be formed as a single unit.

[0050] The stator core (310) may include a cylindrical yoke and a plurality of teeth protruding radially from the yoke.

[0051] A plurality of the above-mentioned teeth may be spaced apart from each other along the circumferential direction of the yoke. Accordingly, a slot, which is a space for winding a coil (330), may be formed between each of the above-mentioned teeth.

[0052] Meanwhile, the teeth of the stator (300) may be arranged to have an air gap with the rotor (400). Here, the air gap may be the distance between the teeth and the magnet (420) in the radial direction.

[0053] The insulator (320) insulates the stator core (310) and the coil (330). Accordingly, the insulator (320) can be placed between the stator core (310) and the coil (330).

[0054] Accordingly, the coil (330) can be wound on the stator core (310) on which the insulator (320) is placed.

[0055] The rotor (400) rotates through electrical interaction with the stator (300). At this time, the rotor (400) can be rotatably positioned on the stator (300).

[0056] Referring to FIGS. 1 to 5, the rotor (400) can be formed by stacking a plurality of unit rotors (400A) stacked in the axial direction. Accordingly, since the motor forms the rotor (400) using a unified unit rotor (400A), productivity can be improved. Here, the unit rotor (400A) may be called a puck.

[0057] Additionally, based on the axial direction, the unit rotor (400A) can be divided into a first unit rotor (400Aa), a second unit rotor (400Ab), and a third unit rotor (400Ac). That is, the first unit rotor (400Aa), the second unit rotor (400Ab), and the third unit rotor (400Ac) can be stacked in the axial direction to form the rotor (400). Here, the rotor (400) is exemplified as being formed using at least three unit rotors (400A), but is not necessarily limited thereto. For example, it may be formed using four or more unit rotors (400A).

[0058] Additionally, the rotor (400) can be configured such that a plurality of unit rotors (400A) are arranged at a certain angle relative to the circumferential direction, thereby allowing a skew angle to be formed between the unit rotors (400A). For example, the rotor can be manufactured as a skew type in which a plurality of unit rotors (400A) are arranged at a certain angle relative to the circumferential direction by utilizing a hole (414) formed in the rotor core body (411) of the unit rotor (400A).

[0059] FIG. 6 is a perspective view showing a unit rotor of a rotor placed in a motor according to an embodiment, FIG. 7 is an exploded perspective view showing a unit rotor of a rotor placed in a motor according to an embodiment, and FIG. 8 is a cross-sectional view showing a unit rotor of a rotor placed in a motor according to an embodiment.

[0060] Referring to FIGS. 6 to 8, the unit rotor (400A) may include a rotor core (410), a plurality of magnets (420) disposed on the outer surface of the rotor core (410), and a can (430) disposed to cover the magnets (420). At this time, the magnets (420) may be disposed at predetermined intervals along the circumferential direction on the rotor core (410) with respect to the center (C). Furthermore, the rotor core (410) and the magnets (420), and the magnets (420) and the can (430) may be joined through an adhesive member.

[0061] The rotor core (410) may be implemented in a shape in which a plurality of plates in the form of thin steel plates are stacked, or in the form of a single tube. At this time, the rotor core (410) may be formed to have a predetermined length (L1) in the axial direction. Here, the axial length (L1) of the rotor core (410) may be called a first length or axial height.

[0062] Referring to FIGS. 6 to 8, the rotor core (410) may include a cylindrical rotor core body (411), a plurality of guides (412) extending outwardly from the outer surface of the rotor core body (411) and protruding, a hole (413) formed at the center (C) of the rotor core body (411), and a plurality of holes (414) formed along the circumferential direction in the rotor core body (411).

[0063] The rotor core body (411) may be formed in a cylindrical shape, and a hole (413) to which a shaft (500) is coupled may be formed at the center (C).

[0064] The above guide (412) can be formed integrally with the rotor core body (411).

[0065] The above guide (412) can guide the placement of the magnet (420). Accordingly, the magnet (420) can be placed between the guides (412) with respect to the circumferential direction. At this time, the magnet (420) can be supported by the guide (412) to prevent movement in the circumferential direction. Here, the guide (412) can be formed lengthwise along the axial direction on the outer surface of the rotor core body (411).

[0066] The hole (414) may be formed in the rotor core body (411) so as to penetrate the rotor core body (411) in the axial direction. Here, a plurality of holes (414) may be formed spaced apart from each other along the circumferential direction.

[0067] The hole (414) may be used when the unit rotors (400A) of the rotor (400) are arranged at a certain angle so that a skew angle can be formed between the unit rotors (400A). For example, a skew angle can be formed between the unit rotors (400A) by using a device such as a jig inserted into the hole (414).

[0068] The above magnet (420) forms a rotating magnetic field with the coil (330) wound on the stator core (310) of the stator (300).

[0069] Accordingly, the rotor (400) rotates due to the electrical interaction between the coil (330) and the magnet (420), and the driving force of the motor is generated by the shaft (500) rotating in conjunction with the rotation of the rotor (400).

[0070] The above magnet (420) is positioned on the outside of the rotor core (410) to implement a Surface Permanent Magnet (SPM) type unit rotor (400A).

[0071] Based on the radial direction, the magnet (420) can be positioned between the outer surface of the rotor core body (411) and the can (430). Also, the magnet (420) can be guided by the guide (412).

[0072] Meanwhile, the magnet (420) may be formed to have a predetermined length (L2) in the axial direction. Here, the axial length (L2) of the magnet (420) may be referred to as the second length. Also, the axial length (L2) of the magnet (420) is smaller than the axial length (L1) of the rotor core (410).

[0073] The can (430) can protect the rotor core (410) and the magnet (420) from physical or chemical stimuli. Additionally, the can (430) can prevent the magnet (420) from detaching from the rotor core (410). Here, the can (430) may be positioned to cover a portion of the magnet (420).

[0074] The can (430) may include a body (431) positioned on the outside of the magnet (420), and a plate portion (432) extending inwardly in the radial direction from one end of the body (431). Here, the body (431) and the plate portion (432) may be formed integrally. For example, the plate portion (432) may be formed by bending one end of the body (431).

[0075] The body (431) may be positioned on the outside of the rotor core (410). Additionally, a portion of the inner surface of the body (431) may be positioned to be in contact with the magnet (420).

[0076] The above body (431) can be formed in a pipe shape.

[0077] The above plate portion (432) may extend only from one end of the body (431). Accordingly, the vertical cross-section of the can (430) may be formed in an L-shape.

[0078] Additionally, the plate portion (432) may come into contact with one axial surface of the magnet (420). For example, the lower surface of the plate portion (432) may come into contact with one axial surface of the magnet (420). That is, the plate portion (432) and one axial surface of the magnet (420) disposed in one of the unit rotors (400A) may come into contact with each other. Accordingly, in one of the unit rotors (400A), one axial surface of the magnet (420) comes into contact with the plate portion (432), and the other surface of the magnet (420) may be exposed from the can (430).

[0079] Additionally, the inner surface (432a) of the plate portion (432) may come into contact with the guide (412) as shown in FIG. 2. Accordingly, the plate portion (432) may be positioned to overlap axially with an outer portion of the magnet (420). And, the plate portion (432) is positioned not to overlap axially with the rotor core (410).

[0080] Meanwhile, the can (430) may be formed to have a predetermined length (L3) in the axial direction. At this time, the can (430) may be formed to have a predetermined thickness (t). Here, the axial length (L3) of the can (430) may be called the third length.

[0081] Here, the thickness (t) of the can (430) may be smaller than the difference (L1-L2) between the axial length (L1) of the rotor core (410) and the axial length (L2) of the magnet (420). For example, the difference (L1-L2) may be 0.02 mm. Here, the difference (L1-L2) may be called an offset.

[0082] Additionally, based on the lower surface of the rotor core (410), the axial length (L3) of the can (430) may be smaller than the axial length (L1) of the rotor core (410) and larger than the axial length (L2) of the magnet (420). At this time, the axial length (L3) of the can (430) may be the same as the axial length (L1) of the rotor core (410), but considering assembly tolerances, it is preferable that the axial length (L3) of the can (430) be formed to be smaller than the axial length (L1) of the rotor core (410).

[0083] Accordingly, a plate portion (432) of one of the adjacent unit rotors (400A) may be disposed between the magnet (420) of one of the multiple unit rotors (400A) that are axially adjacent and the magnet (420) of another unit rotor (400A).

[0084] Additionally, a space may be formed between the plate portion (432) of one unit rotor (400A) and the magnet (420) of the unit rotor (400A) that is axially adjacent. As illustrated in FIG. 5, the plate portion (432) of one unit rotor (400A) may be positioned to have a predetermined spacing (G) from the magnet (420) of another unit rotor (400A) that is axially adjacent. For example, the lower surface of the magnet (420) of the first unit rotor (400Aa) may be positioned to have a predetermined spacing (G) from the plate portion (432) of the second unit rotor (400Ab). At this time, the lower surface of the magnet (420) of the first unit rotor (400Aa) may be positioned to face the plate portion (432) of the second unit rotor (400Ab) in the axial direction.

[0085] Additionally, among the plurality of unit rotors (400A), the magnet (420) of one unit rotor (400A) and the magnet (420) of another unit rotor (400A) that are arranged adjacently in the axial direction may come into contact with each other. As shown in FIG. 5, the magnet (420) of one unit rotor (400A) may be arranged to come into contact with the magnet (420) of another unit rotor (400A) that is arranged adjacently in the axial direction. For example, the lower surface of the magnet (420) of the second unit rotor (400Ab) may come into contact with the upper surface of the magnet (420) of the third unit rotor (400Ac). Accordingly, the lower surface of the magnet (420) of the second unit rotor (400Ab) may be arranged to face each other with the upper surface of the magnet (420) of the third unit rotor (400Ac).

[0086] Meanwhile, when forming the rotor (400) by stacking a single unit rotor (400A) in the axial direction, the first unit rotor (400Aa) and the third unit rotor (400Ac) may be arranged symmetrically with respect to each other in order to protect the magnet (420) placed inside the rotor (400) as much as possible.

[0087] For example, when a second unit rotor (400Ab) is placed between a first unit rotor (400Aa) and a third unit rotor (400Ac), the plate portion (432) of the first unit rotor (400Aa) is positioned at the top and the plate portion (432) of the third unit rotor (400Ac) is positioned at the bottom with respect to the axial direction, thereby protecting the magnet (420) placed in each unit rotor (400A) to the maximum extent.

[0088] In addition, the rotor (400) can improve productivity because it pre-manufactures a single unit rotor (400A) and then presses each unit rotor (400A) into the shaft (500).

[0089] In the conventional method, a rotor core (410) is pressed into a shaft (500) to assemble it, and then a magnet (420) is attached to the rotor core (410) through a bonding process using an adhesive. Then, a predetermined amount of time is required until the adhesive is cured (curing process of the adhesive). After that, the can (430) is bonded to the magnet (420) using the adhesive. Since a curing process for the adhesive must also be involved in this process, there is a problem of increased production time.

[0090] However, since the rotor (400) according to the embodiment is manufactured by pre-fabricating a single unit rotor (400A) and press-fitting it, the production time can be reduced. Accordingly, the productivity of the motor can be improved.

[0091] The shaft (500) can be rotatably positioned inside the housing (100) by means of a bearing (B). And, the shaft (500) can rotate together with the rotation of the rotor (400).

[0092] And, the shaft (500) can be joined by a press-fit method to a hole (413) formed in the center of the rotor core (410).

[0093] Here, the rotor (400) to which the shaft (500) is attached may be called a shaft assembly or a rotor assembly. Accordingly, the shaft assembly may be provided as a single unit for the assembly of the motor.

[0094] The busbar (600) can be placed on the upper part of the stator (300).

[0095] And, the busbar (600) can be electrically connected to the coil (330) of the stator (300).

[0096] The busbar (600) may include a busbar body (not shown) and a plurality of terminals (not shown) disposed inside the busbar body. Here, the busbar body may be a molded body formed by injection molding. And, each of the terminals may be electrically connected to a coil (330) of a stator (300).

[0097] The sensor unit (700) detects the magnetic force of a sensing magnet installed to rotate in conjunction with the rotor (400) and determines the current position of the rotor (400), thereby enabling the detection of rotation of the shaft (500).

[0098] The sensor unit (700) may include a sensing magnet assembly (710) and a printed circuit board (PCB, 720).

[0099] The sensing magnet assembly (710) is coupled to the shaft (500) to work in conjunction with the rotor (400) so as to detect the position of the rotor (400). At this time, the sensing magnet assembly (710) may include a sensing magnet and a sensing plate.

[0100] The above sensing magnet may include a main magnet arranged circumferentially adjacent to a hole forming an inner surface and a sub-magnet formed at the edge.

[0101] The above main magnet can be arranged in the same way as the drive magnet inserted into the rotor (400) of the motor.

[0102] The above sub-magnet can be formed to have more poles than the above main magnet, with more fine divisions. Accordingly, the above sub-magnet makes it possible to measure the rotation angle by dividing it more finely and can induce smoother driving of the motor.

[0103] The sensing plate may be formed from a disc-shaped metal material. A sensing magnet may be attached to the upper surface of the sensing plate. The sensing plate may be attached to a shaft (500). Here, a hole through which the shaft (500) passes may be formed in the sensing plate.

[0104] A sensor for detecting the magnetic force of the sensing magnet may be placed on the printed circuit board (720). Here, the sensor may be provided as a Hall IC. The sensor may generate a sensing signal by detecting a change in the N and S poles of the sensing magnet. Accordingly, the printed circuit board (720) on which the Hall IC is placed may be called a sensing assembly or a position sensing device.

[0105] Although the present invention has been described above with reference to preferred embodiments, those skilled in the art will understand that various modifications and changes can be made to the invention without departing from the spirit and scope of the invention as described in the following claims. Explanation of the symbols

[0106] 1: Motor 100: Housing 200: Cover 300: Status 310: Status Core 330: Coil 400: Rotor 400A: Unit rotor 400Aa: 1st unit rotor 400Ab: 2nd unit rotor 400Ac: 3rd unit rotor 410: Rotor core 412: Rotor core body 412: Guide 420: Magnet 430: Can 431: Body 432: Plate section 500: Shaft 600: Busbar 700: Sensor section

Claims

Claim 1 A motor comprising a stator; a rotor formed by a plurality of unit rotors; and a shaft coupled to the rotor, wherein the unit rotor comprises a rotor core coupled to the shaft, a plurality of magnets disposed on the outer side of the rotor core, and a can disposed to cover the magnets, wherein the can comprises a pipe-shaped body and a plate portion extending radially from only one end of the body, and wherein the rotor core comprises a rotor core body and a guide protruding radially from the outer surface of the rotor core body, and the outer surface of the guide contacts the inner surface of the plate portion. Claim 2 In claim 1, the motor in which, based on the lower surface of the rotor core, the axial length (L3) of the body is smaller than the axial length (L1) of the rotor core and larger than the axial length (L2) of the magnet. Claim 3 In paragraph 2, the thickness (t) of the can is smaller than the difference (L1-L2) between the axial length (L1) of the rotor core and the axial length (L2) of the magnet. Claim 4 A motor according to paragraph 2, wherein a plate portion of one of the adjacent unit rotors is disposed between the magnet of one unit rotor and the magnet of another unit rotor disposed adjacently in the axial direction. Claim 5 In paragraph 2, when a plate portion of one of the adjacent unit rotors is disposed between the magnet of one unit rotor disposed adjacently in the axial direction and the magnet of another unit rotor, the plate portion of one of the unit rotors has a predetermined spacing (G) from the magnet of the other unit rotor. Claim 6 In paragraph 2, a motor in which the magnet of any one of the axially adjacent unit rotors contacts the magnet of another unit rotor. Claim 7 delete Claim 8 In claim 1, the plate portion disposed on one of the unit rotors and the axial surface of the magnet are in contact with each other. Claim 9 A stator; a rotor positioned to correspond to the stator; A motor comprising a shaft coupled to the rotor, wherein the rotor comprises a first unit rotor, a second unit rotor disposed below the first unit rotor, and a third unit rotor disposed below the second unit rotor, and each of the first unit rotor, the second unit rotor, and the third unit rotor comprises a rotor core coupled to the shaft, a plurality of magnets disposed on the outside of the rotor core, and a can disposed to cover the magnets, wherein the can comprises a pipe-shaped body and a plate portion extending radially from only one end of the body, wherein the plate portion of the can disposed in the second unit rotor is disposed facing the lower surface of the magnet disposed in the first unit rotor, and the lower surface of the magnet disposed in the second unit rotor is disposed facing the upper surface of the magnet disposed in the third unit rotor, and wherein the rotor core comprises a rotor core body and a guide protruding radially from the outer surface of the rotor core body, and the outer surface of the guide contacts the inner surface of the plate portion. Claim 10 In claim 9, a space is formed in the axial direction between the lower surface of the magnet disposed in the first unit rotor and the plate portion of the can disposed in the second unit rotor, and the lower surface of the magnet disposed in the second unit rotor and the upper surface of the magnet disposed in the third unit rotor are in contact with each other. Claim 11 A rotor formed by a plurality of unit rotors arranged axially, wherein the unit rotor comprises a rotor core, a plurality of magnets arranged along the outer surface of the rotor core, and a can arranged to cover the magnets, wherein the can comprises a pipe-shaped body and a plate portion extending radially from only one end of the body, wherein in one of the unit rotors, one axial surface of the magnet contacts the plate portion and the other axial surface is exposed from the can, wherein the rotor core comprises a rotor core body and a guide protruding radially from the outer surface of the rotor core body, and the outer surface of the guide contacts the inner surface of the plate portion.

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