Patent Publication Number: US-2023137883-A1

Title: Motor

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is the U.S. national stage application of International Patent Application No. PCT/KR2021/000650, filed Jan. 18, 2021, which claims the benefit under 35 U.S.C. § 119 of Korean Application Nos. 10-2020-0024341, filed Feb. 27, 2020; and 10-2020-0027383, filed Mar. 4, 2020; the disclosures of each of which are incorporated herein by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a rotor and a motor including the same. 
     BACKGROUND ART 
     Motors are apparatuses configured to convert electrical energy to mechanical energy to obtain rotational forces and are widely used for vehicles, home appliances, industrial machines, and the like. 
     A motor may include a housing, a shaft, a stator disposed on an inner circumferential surface of the housing, a rotor disposed on an outer circumferential surface of the shaft, and the like. In this case, the stator induces an electrical interaction with the rotor to induce rotation of the rotor. 
       FIG.  1    is a view illustrating a rotor and a shaft of a conventional spoke type motor. 
     Referring to  FIG.  1   , the conventional spoke type motor may include a rotor  10  and a shaft  20  coupled to the rotor  10 . 
     The rotor  10  includes a rotor yoke  11  and a plurality of rotor teeth  12 , and magnets  13  are disposed between the rotor teeth  12 . In this case, the magnets  13  are disposed to extend radially on the rotor  10  when viewed from above. In the case of such a spoke type motor, it is characterized by having high output power. In this case, each of the magnets  13  is formed in a shape in which a length in a radial direction is greater than a width. 
     Referring to  FIG.  1   , the magnet  13  may be formed in a long bar shape. In this case, the conventional spoke type motor may include protrusions  12   a  formed on the rotor teeth  12  to inhibit separation of the magnets  13 . 
     However, there is a problem of a flux leakage due to the protrusions  12   a.    
     In addition, there is a problem that the protrusions  12   a  can inhibit the separation of the magnets  13  only in the radial direction and cannot inhibit the separation of the magnets  13  in an axial direction. 
     Accordingly, the rotor of the conventional spoke type motor may further include a can or over molding structure to inhibit the separation of the magnets  13  in the axial direction while assisting the protrusions  12   a.    
     However, in the can or over molding structure using a mold part, an air gap between the rotor  10  and a stator increases in the radial direction, and thus there is a problem of an in increase in size of the motor. Otherwise, when a size of a motor is fixed, the can or over molding structure has a problem of air gap loss. 
     Accordingly, a motor capable of inhibiting not only a flux leakage occurring due to the protrusions  12   a  but also an increase in air gap is required. 
     Technical Problem 
     The present invention is directed to providing a motor which inhibits a leakage of a flux and separation of a magnet and is compact in a radial direction. 
     The present invention is directed to providing a motor capable of inhibiting a leakage of a magnetic flux of a magnet. 
     Objectives to be solved by the present invention are not limited to the above-described objectives, and other objectives, which are not described above, will be clearly understood by those skilled in the art from the following description. 
     Technical Solution 
     One aspect of the present invention provides a motor including a stator, a rotor disposed to correspond to the stator, and a shaft coupled to the rotor, wherein the rotor includes a rotor core including a yoke and a plurality of rotor teeth disposed apart from each other on the yoke in a circumferential direction, a plurality of magnets disposed between the rotor teeth, and a can disposed outside the rotor core, the can includes a first can in which a hole is formed and a second can including a protruding part coupled to the hole, and a part of the protruding part is disposed to face an outer surface of each of the magnets. 
     A radius (R1) of each of the rotor teeth may be greater than radius (R6) of the protruding part. In this case, the radius (R6) of the protruding part may be a distance from an outer surface of the protruding part to a center (C) of the shaft. 
     An outer radius (R3) of the first can may be smaller than or equal to the radius (R1) of the rotor tooth or greater than a radius (R2) of the magnet. In this case, the radius (R2) of the magnet may be a distance from the center (C) of the shaft to the outer surface of the magnet. 
     The first can may be formed in a ring shape, and the radius (R2) of the magnet may be smaller than the outer radius (R3) of the first can and greater than an inner radius (R4) of the first can. 
     The first can may be formed in a ring shape, and the first can may be disposed to overlap a part of the magnet in an axial direction. 
     The stator may include a stator core and a coil wound around the stator core, the stator core may include a plurality of teeth disposed apart from each other in the circumferential direction, and a distance (D1) from an inner circumferential surface of each of the teeth to an outer surface of the rotor tooth may be smaller than a distance (D2) from the inner circumferential surface of the tooth to the protruding part. 
     Another aspect of the present invention provides a rotor including a rotor core which includes a yoke and a plurality of rotor teeth disposed apart from each other on the yoke in a circumferential direction, a plurality of magnets disposed between the rotor teeth, and a can disposed on the rotor core on which the plurality of magnets are disposed, wherein the can includes a first can in which a hole is formed and a second can including a body and a protruding part extending from the body in an axial direction, the protruding part coupled to the hole is disposed to face an outer surface of the magnet. 
     A length of the protruding part may be greater than a length of the rotor core in the axial direction, and an end portion of the protruding part coupled to the hole may be bent. 
     Still another aspect of the present invention provides a motor including a shaft, a rotor disposed outside the shaft, and a stator disposed outside the rotor, wherein the rotor includes a plurality of rotor teeth, a magnet disposed between the plurality of rotor teeth in a circumferential direction, and a first member disposed between the shaft and the rotor teeth in a radial direction, the first member is formed of a non-magnetic material, and a part of each of the rotor teeth and a part of the first member are disposed to overlap in the circumferential direction. 
     Yet another aspect of the present invention provides a motor including a shaft, a rotor disposed outside the shaft, and a stator disposed outside the rotor, wherein the rotor includes a rotor tooth, a magnet in contact with the rotor tooth, and a first member disposed between the shaft and the rotor tooth in a radial direction and formed of a not-magnetic material, the first member includes an outer circumferential surface in contact with the magnet, an inner circumferential surface in contact with the shaft, and a first groove and a second groove which are disposed between the outer circumferential surface and the inner circumferential surface in the radial direction and communicate with each other, the second groove is disposed to be closer to the inner circumferential surface than the first groove in the radial direction, a width of the second groove in a circumferential direction is greater than a width of the first groove in the circumferential direction, and a part of the rotor tooth is disposed in the first groove and the second groove. 
     The first member may include a first groove and a second groove which communicate with each other, the second groove may be disposed to be closer to an inner circumferential surface than the first groove in the radial direction, a width of the second groove in the circumferential direction may be greater than a width of the first groove in the circumferential direction, and a part of the rotor tooth may be disposed in the first groove and the second groove. 
     The rotor tooth may include a first protrusion protruding toward the shaft, the second groove may include a first surface and a second surface disposed in opposite directions, and at least any one of the first surface and the second surface may be in contact with the first protrusion in an axial direction. 
     The rotor tooth may include a first protrusion protruding toward the shaft, the second groove may include a first surface and a second surface disposed in opposite directions in the radial direction, and at least any one of the first surface and the second surface may include a first region in contact with the first protrusion and a second region which is not in contact with the first protrusion. 
     The second groove may include a first surface and a second surface disposed in opposite directions in the radial or diagonal direction, and at least any one of the first surface and the second surface may include a plurality of second protrusions. 
     A part of the first protrusion may be in contact with the second protrusions disposed on the second surface, and another part of the first protrusion may be in surface contact with the first surface. 
     An inner surface of a plurality of surfaces of the magnet may be disposed toward the shaft, a part of the inner surface may be in contact with an outer circumferential surface of the first member, and the other part of the inner surface may be disposed apart from the outer circumferential surface of the first member. 
     The magnet and the first member may be in line contact with each other in an axial direction. 
     The rotor tooth may include a first protrusion protruding toward the shaft, the first protrusion may include a 1-1 protrusion and a 1-2 protrusion protruding from the 1-1 protrusion, and a width of the 1-2 protrusion in the circumferential direction may be greater than a width of the 1-1 protrusion in the circumferential direction. 
     Advantageous Effects 
     According to embodiments, the present invention can inhibit separation of a magnet using a protruding part of a can disposed to face an outer circumferential surface of the magnet. 
     In addition, according to the embodiments, since a protrusion formed on a rotor tooth of a conventional spoke type motor can be omitted using the protruding part of the can, a flux leakage due to the conventional protrusion can be inhibited. 
     In addition, since the protruding part is disposed further inward than an outer circumferential surface of a rotor core in a radial direction, a motor having a smaller size than the conventional spoke type motor in the radial direction can be implemented. 
     That is, according to the embodiments, the motor which inhibits separation of the magnet and a leakage of a flux and is more compact than the conventional spoke type motor in the radial direction can be implemented. 
     According to the embodiments, the present invention provides an advantageous effect of inhibiting a leakage of a magnetic flux flowing toward a shaft. 
     According to the embodiments, there are advantages that assembly of the rotor tooth is easy, and movement of the rotor tooth is inhibited after the rotor tooth is assembled. 
     Various useful advantages and effects of the embodiments are not limited to the above-described contents and will be more easily understood from descriptions of the specific embodiments. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG.  1    is a view illustrating a rotor and a shaft of a conventional spoke type motor. 
         FIG.  2    is a view illustrating a motor according to an embodiment. 
         FIG.  3    is a cross-sectional view along line A-A of  FIG.  2   . 
         FIG.  4    is a bottom perspective view illustrating a state in which a rotor and a shaft according to a first embodiment disposed in the motor according to the embodiment are coupled. 
         FIG.  5    is a perspective view illustrating the rotor according to the first embodiment disposed in the motor according to the embodiment. 
         FIG.  6    is a plan view illustrating the rotor according to the first embodiment disposed in the motor according to the embodiment. 
         FIG.  7    is a bottom view illustrating the rotor according to the first embodiment disposed in the motor according to the embodiment. 
         FIG.  8    is a plan view illustrating an arrangement relationship between a rotor core and magnets of the rotor according to the first embodiment. 
         FIGS.  9 A- 9 C  are a set of views illustrating a process in which a can is disposed on a rotor assembly of the rotor according to the first embodiment. 
         FIG.  10    is a view illustrating a first can of the motor according to the embodiment. 
         FIG.  11    is a view illustrating a second can of the motor according to the embodiment. 
         FIG.  12    is a view illustrating a rotor according to a second embodiment. 
         FIG.  13    is a plan view illustrating a rotor tooth of the rotor according to the second embodiment. 
         FIG.  14    is a plan view illustrating a first member of the rotor according to the second embodiment. 
         FIG.  15    is a plan view illustrating a first groove and a second groove of the first member of the rotor according to the second embodiment. 
         FIG.  16    is a view illustrating a modified example of the second groove of the first member of the rotor according to the second embodiment. 
         FIG.  17    is a view illustrating anther modified example of the second groove of the first member of the rotor according to the second embodiment. 
         FIG.  18    is a view illustrating a state in which a first protrusion of a rotor core is coupled to the first groove and the second groove of the first member of the rotor according to the second embodiment. 
         FIG.  19    is a view illustrating a state in which a magnet and the first member of the rotor according to the second embodiment are in contact with each other. 
     
    
    
     MODES OF THE INVENTION 
     Hereinafter, exemplary embodiments of the present invention will be described in detail with reference the accompanying drawings. 
     However, the technical spirit of the present invention is not limited to some embodiments which will be described and may be embodied in a variety of different forms, and at least one or more components of the embodiments may be selectively combined, substituted, and used within the range of the technical spirit. 
     In addition, unless clearly and specifically defined otherwise by the context, all terms (including technical and scientific terms) used herein can be interpreted as having meanings customarily understood by those skilled in the art, and meanings of generally used terms, such as those defined in commonly used dictionaries, will be interpreted in consideration of contextual meanings of the related art. 
     In addition, the terms used in the embodiments of the present invention are considered in a descriptive sense only and not to limit the present invention. 
     In the present specification, unless clearly indicated otherwise by the context, singular forms include the plural forms thereof, and in a case in which “at least one (or one or more) among A, B, and C” is described, this may include at least one combination among all possible combinations of A, B, and C. 
     In addition, in descriptions of components of the present invention, terms such as “first,” “second,” “A,” “B,” “(a),” and “(b)” can be used. 
     The terms are only to distinguish one element from another element, and the essence, order, and the like of the elements are not limited by the terms. 
     In addition, it should be understood that, when an element is referred to as being “connected” or “coupled” to another element, such a description may include both a case in which the element is directly connected or coupled to another element, and a case in which the element is connected or coupled to another element with still another element disposed therebetween. 
     In addition, when any one element is described as being formed or disposed “on” or “under” another element, such a description includes both a case in which the two elements are formed or disposed in direct contact with each other and a case in which one or more other elements are interposed between the two elements. In addition, when one element is described as being formed “on or under” another element, such a description may include a case in which the one element is formed at an upper side or a lower side with respect to another element. 
     Hereinafter, in the detailed description of the example embodiments of the invention with reference to the accompanying drawings, components that are the same or correspond to each other will be denoted by the same reference numerals in all of the figures, and redundant descriptions will be omitted. 
     First Embodiment 
       FIG.  2    is a view illustrating a motor according to an embodiment,  FIG.  3    is a cross-sectional view along line A-A of  FIG.  2   , and  FIG.  4    is a bottom perspective view illustrating a state in which a rotor and a shaft according to a first embodiment disposed in the motor according to the embodiment are coupled. In  FIG.  2   , an x direction may be a radial direction, and a y direction may be an axial direction. In addition, the axial direction and the radial direction may be perpendicular to each other. In this case, the axial direction may be a longitudinal direction of a shaft  500 . 
     Referring to  FIGS.  2  and  3   , a motor  1  according to the embodiment may include a housing  100  having one side at which an opening is formed, a cover  200  disposed on the housing  100 , a stator  300  disposed in the housing  100 , a rotor  400  disposed inside the stator  300 , and the shaft  500  coupled to the rotor  400 . In addition, the motor  1  may include a busbar  600  disposed above the stator  300  and a sensor part  700  which detects rotation of the rotor  400 . In this case, as illustrated in  FIG.  4   , the rotor  400  coupled to the shaft  500  may be referred to as a shaft assembly. In addition, the term “inward” may be a direction toward a rotation center C of the motor  1  in the radial direction, and the term “outward” may be a direction opposite to “inward.” In addition, the rotation center C of the motor  1  may be an axial center of the shaft  500 . 
     The housing  100  and the cover  200  may form an exterior of the motor  1 . In addition, an accommodation space may be formed by coupling the housing  100  and the cover  200 . Accordingly, as illustrated in  FIG.  2   , the stator  300 , the rotor  400 , the shaft  500 , the busbar  600 , the sensor part  700 , and the like may be disposed in the accommodation space. 
     In this case, the shaft  500  is rotatably disposed in the accommodation space. Accordingly, the motor  1  may further include bearings B disposed on upper and lower portions of the shaft  500 . In this case, the bearing B disposed in the housing  100  may be referred to as a first bearing or lower bearing, and the bearing B disposed in the cover  200  may be referred to as a second bearing or upper bearing. 
     The housing  100  may be formed in a cylindrical shape. In addition, the housing  100  may accommodate the stator  300 , the rotor  400 , and the like therein. In this case, a shape or material of the housing  100  may be variously changed. For example, the housing  100  may be formed of a metal material which firmly withstands even high temperatures. 
     The housing  100  may include a pocket part for accommodating the bearing B in a lower portion. In this case, the pocket part of the housing  100  may be referred to as a housing pocket part. 
     The cover  200  may be disposed on an open surface of the housing  100 , that is, an upper portion of the housing  100 , to cover the opening of the housing  100 . 
     In addition, the cover  200  may include a pocket part for accommodating the bearing B. In this case, the pocket part of the cover  200  may be referred to as a cover pocket part. 
     The stator  300  induces an electrical interaction with the rotor  400  to induce rotation of the rotor  400 . 
     The stator  300  may be disposed inside the housing  100 . In this case, the stator  300  may be supported by an inner circumferential surface of the housing  100 . In addition, the stator  300  may be disposed outside the rotor  400 . That is, the rotor  400  may be rotatably disposed inside the stator  300 . 
     Referring to  FIG.  3   , the stator  300  may include a stator core  310 , insulators  320  disposed on the stator core  310 , and coils  330  wound around the insulators  320 . 
     The coils  330  which generate a rotating magnetic field may be wound around the stator core  310 . In this case, the stator core  310  may be formed as a single core or formed by coupling a plurality of divided cores. 
     The stator core  310  may be formed in a form in which a plurality of thin steel plates are stacked but is not necessarily limited thereto. For example, the stator core  310  may also be formed as one single part. 
     The stator core  310  may include a yoke  311  having a cylindrical shape and a plurality of teeth  312  protruding from the yoke  311  in a radial direction. In this case, the yoke  311  may be referred to as a stator yoke. In addition, the teeth  312  may be referred to as stator teeth. 
     The plurality of teeth  312  may be disposed apart from each other in a circumferential direction of the yoke  311 . Accordingly, slots in which the coils  330  are wound around the teeth  312  may be formed between the teeth  312 . 
     Meanwhile, the teeth  312  of the stator  300  may be disposed to have an air gap between the teeth  312  and the rotor  400 . In this case, the air gap may be a distance from an inner circumferential surface  312   a  of each of the teeth  312  to an outer circumferential surface of the rotor  400 . Specifically, the air gap may be a shortest distance from the inner circumferential surface  312   a  of the tooth  312  to an outer surface  412   a  of a rotor tooth  412  of the rotor  400  in the radial direction. 
     The insulators  320  insulate the stator core  310  from the coils  330 . Accordingly, the insulators  320  may be disposed between the stator core  310  and the coils  330 . 
     Accordingly, the coils  330  may be wound around the stator core  310  on which the insulators  320  are disposed. 
     The rotor  400  rotates due to an electrical interaction with the stator  300 . In this case, the rotor  400  may be rotatably disposed inside the stator  300 . 
       FIG.  5    is a perspective view illustrating the rotor according to the first embodiment disposed in the motor according to the embodiment,  FIG.  6    is a plan view illustrating the rotor according to the first embodiment disposed in the motor according to the embodiment,  FIG.  7    is a bottom view illustrating the rotor according to the first embodiment disposed in the motor according to the embodiment,  FIG.  8    is a plan view illustrating an arrangement relationship between the rotor core and magnets of the rotor according to the first embodiment, and  FIGS.  9 A- 9 C  are a set of views illustrating a process in which a can is disposed on a rotor assembly of the rotor according to the first embodiment. 
     Referring to  FIGS.  5  to  9 C , the rotor  400  may include a rotor core  410 , a plurality of magnets  420  disposed on the rotor core  410 , and a can  430  disposed on the rotor core  410  coupled to the magnets  420 . In this case, the magnets  420  may be radially disposed on the rotor core  410  based on a center C. In this case, the rotor  400  may be the rotor according to the first embodiment and may be referred to as a first rotor. 
     The rotor core  410  may be formed in a form in which a plurality of thin steel plates are stacked or formed in one container form. In addition, a hole coupled to the shaft  500  may be formed at the center C of the rotor core  410 . 
     The rotor core  410  may include a yoke  411  and a plurality of rotor teeth  412  disposed apart from each other on the yoke  411  in a circumferential direction. 
     The yoke  411  may be formed in a cylindrical shape having a central portion in which a hole is formed to be coupled to the shaft  500 . As illustrated in  FIG.  8   , the yoke  411  may include protrusions  411   a  disposed to face one inner surfaces of the magnets  420 . In this case, the protrusions  411   a  may be disposed between the rotor teeth  412  in the circumferential direction. In addition, an end portion of each of the protrusions  411   a  may be in contact with one inner surface of one of the magnets  420 . 
     The rotor teeth  412  may be formed to protrude from an outer circumferential surface of the yoke  411  in the radial direction. In this case, the plurality of rotor teeth  412  may be disposed apart from each other in the circumferential direction. 
     That is, the plurality of rotor teeth  412  may be radially disposed based on the center C of the rotor  400 . In this case, since the rotor teeth  412  may be formed apart from each other in the circumferential direction, open portions may be formed. Accordingly, spaces in which the magnets  420  are disposed may be formed between the rotor teeth  412  in the circumferential direction. In addition, an outer side, which is one side, of the magnet  420  may be open (exposed). 
     In addition, the rotor tooth  412  may be disposed to have a predetermined radius R1 based on the center C of the rotor  400 . For example, the plurality of rotor teeth  412  may be disposed on the predetermined radius R1. In this case, the radius R1 may be referred to as a first radius and a distance from the center C to the outer surface  412   a  of the rotor tooth  412 . 
     In addition, the outer surface  412   a  of the rotor tooth  412  may be disposed to have a predetermined distance D1 to the inner circumferential surface  312   a  of the tooth  312  of the stator  300 . In this case, the distance D1 may be referred to as a first distance. 
     The plurality of magnets  420  may be disposed between the rotor teeth  412 . In this case, each of the magnets  420  may be formed in a long bar shape. 
     Each of the magnets  420  may be disposed to have a predetermined radius R2 based on the center C of the rotor  400 . For example, the plurality of magnets  420  may be disposed on the predetermined radius R2. In this case, the radius R2 may be referred to as a second radius and may be a distance from the center C to an outer surface  421  of the magnet  420 . In this case, the radius R2 of the magnet  420  may be the distance from the center C of the shaft  500  to the outer surface  421  of the magnet  420  in the radial direction. In addition, the radius R2 of the magnet  420  is smaller than the radius R1 of the rotor tooth  412 . 
     The magnets  420  generate a rotating magnetic field with the coils  330  wound around the stator core  310  of the stator  300 . 
     Accordingly, due to an electrical interaction between the coils  330  and the magnets  420 , the rotor  400  rotates, and the shaft  500  rotates in conjunction with the rotation of the rotor  400  so that a driving force of the motor  1  is generated. 
     The can  430  may be disposed to cover a part of the rotor core  410  to which the magnets  420  are attached. In this case, the rotor core  410  to which the magnets  420  are attached may be referred to as a rotor assembly. 
     The can  430  may protect the rotor core  410  and the magnets  420  from physical or chemical stimulus. In addition, the can  430  may inhibit the magnets  420  from being separated from the rotor core  410 . 
       FIG.  10    is a view illustrating a first can of the motor according to the embodiment, and  FIG.  11    is a view illustrating a second can of the motor according to the embodiment. 
     Referring to  FIGS.  5  to  11   , the can  430  may include a first can  440  and a second can  450  coupled to the first can  440 . 
     The first can  440  may be disposed in contact with a lower portion of the rotor core  410 . In addition, a part of the second can  450  may be disposed in contact with an upper portion of the rotor core  410 , and another portion of the second can  450  may be disposed outside the magnets  420 . Accordingly, the first can  440  and the second can  450  may inhibit the magnets  420  from being separated in an axial direction. In this case, an example of the first can  440  disposed under the rotor core  410  and an example of a part of the second can  450  disposed above the rotor core  410  are described, but the present invention is not necessarily limited thereto. For example, the first can  440  may be disposed above the rotor core  410 , and a part of the second can  450  may also be disposed under the rotor core  410 . 
     The first can  440  may include a plurality of holes  441  disposed apart from each other in the circumferential direction. The holes  441  may be formed in a shape passing through the first can  440  in the axial direction and formed in a shape corresponding to protruding parts  452  of the second can  450  in consideration of coupling with the protruding parts  452  of the second can  450 . 
     In this case, the first can  440  may be formed as a plate having a ring shape. Accordingly, the first can  440  may be disposed to overlap a part of the magnet  420  in the axial direction. In this case, the first can  440  may be disposed in contact with a lower surface of the rotor core  410 . 
     In addition, since the first can  440  is formed as the plate having the ring shape, the first can  440  may have an outer radius R3 and an inner radius R4. In this case, the outer radius R3 may be referred to as a third radius, and the inner radius R4 may be referred to as a fourth radius. 
     The outer radius R3 of the first can  440  may be smaller than or equal to the radius R1 of the rotor tooth  412 . In this case, the outer radius R3 of the first can  440  may be greater than the radius R2 of the magnet  420 . In addition, the inner radius R4 may be smaller than the radius R2 of the magnet  420 . That is, the radius R2 of the magnet may be smaller than the outer radius R3 of the first can  440  and greater than the inner radius R4 of the first can  440 . 
     Meanwhile, the first can  440  may further include a rim  442  extending to protrude upward from an outer circumferential surface in the axial direction. In this case, a cross-section of the rim  442  may be formed in a ring shape. In addition, the rim  442  may be referred to as a sleeve. 
     The rim  442  may be disposed outside of the rotor tooth  412 . 
     As illustrated in  FIG.  6   , an inner circumferential surface of the rim  442  may be disposed in contact with the outer surface  412   a  of the rotor tooth  412 . In addition, the inner circumferential surface of the rim  442  may be disposed apart from the protruding parts  452 . In this case, the rim  442  is an additional component of the first can  440  and may serve as a guide for arranging the first can  440  on the rotor assembly. 
     The second can  450  may include a body  451  and at least two protruding parts  452  protruding from the body  451  in the axial direction. That is, the second can  450  may include the body  451  and the plurality of protruding parts  452  protruding from the body  451  in the axial direction. In this case, the body  451  and the protruding parts  452  may be integrally formed. For example, the body  451  and the protruding parts  452  of the second can  450  may be formed by cutting and bending a material having a plate shape. 
     The body  451  may be formed in a disc shape having a predetermined thickness. In addition, a hole in which the shaft  500  is disposed may be formed in a central portion of the body  451 . In this case, one surface of the body  451  may be disposed in contact with an upper surface of the rotor core  410 . In addition, a radius of the hole formed in the body  451  may be smaller than the inner radius R4 of the first can  440 . 
     In addition, an outer circumferential surface  451   a  of the body  451  may be formed to have a predetermined radius R5. In this case, the radius R5 may be referred to as a fifth radius. In addition, the radius R5 of the outer circumferential surface  451   a  may be smaller than the radius R1 of the rotor tooth  412 . In addition, the radius R5 of the outer circumferential surface  451   a  may be greater than the radius R2 of the magnet  420 . 
     The protruding parts  452  may be formed to protrude from the body  451  in the axial direction. In addition, the protruding parts  452  may be coupled to the holes  441  of the first can  440  and bent to inhibit the magnets  420  from being separated in the axial direction. In this case, the protruding parts  452  may be formed in a plate shape. 
     In addition, the plurality of protruding parts  452  may be disposed apart from each other at predetermined intervals on the body  451  in the circumferential direction. 
     In addition, each of the protruding parts  452  may be formed to face one of the magnets  420 . Specifically, a part of the protruding part  452  may be disposed to overlap the magnet  420  in the radial direction. In this case, the protruding part  452  may be disposed outside the magnet  420 . Accordingly, the protruding part  452  may inhibit the magnet  420  from being separated in the radial direction. In this case, the number of the protruding parts  452  and the number of the magnets  420  are the same. 
     Referring to  FIGS.  9 A- 9 C, and  11   , the protruding part  452  may extend from the outer circumferential surface  451   a  of the body  451  in the axial direction. In this case, the protruding part  452  may be disposed to have a predetermined radius R6 based on the center C of the rotor  400 . For example, the plurality of protruding parts  452  may be disposed on the predetermined radius R6. Accordingly, a distance from an outer surface of the protruding part  452  to the center C of the shaft  500  may be greater than the radius R5 of the outer circumferential surface  451   a . That is, the radius R6 of the protruding part  452  may be greater than the radius R5 of the outer circumferential surface  451   a . In this case, the radius R6 of the protruding part  452  may be a radius of the outer surface of the protruding part  452  and may be referred to as a sixth radius. 
     In addition, the radius R1 of the outer surface of the rotor tooth may be greater than the distance from the outer surface of the protruding part  452  to the center C of the axial center of the shaft  500 . Accordingly, even when the can  430  of the rotor  400  is used, a compact motor can be implemented. 
     Meanwhile, a length of the protruding part  452  may be greater than a length of the rotor core  410  in the axial direction. Accordingly, the protruding part  452  may be coupled to the hole  441  and bent to fix the first can  440 . 
     Meanwhile, the outer surface  412   a  of the rotor tooth  412  may be disposed to have the predetermined distance D1 to the inner circumferential surface  312   a  of the tooth  312  of the stator  300 . In this case, the distance D1 may be referred to as a first distance. 
     In addition, the protruding part  452  may be disposed to have a predetermined distance D2 to the inner circumferential surface  312   a  of the tooth  312  of the stator  300 . In this case, the distance D2 may be referred to as a second distance. 
     Accordingly, in the motor  1 , since the distance D1 from the inner circumferential surface  312   a  of the tooth  312  to the outer surface  412   a  of the rotor tooth  412  is smaller than the distance D2 from the inner circumferential surface  312   a  of the tooth  312  to the protruding part  452 , a loss of the air gap can be inhibited. Accordingly, the motor  1  may be implemented as a compact motor in the radial direction. 
     Referring to  FIGS.  9 A- 9 C , a process in which the can  430  is coupled to the rotor assembly will be described. 
     As illustrated in  FIG.  9 A , the first can  440  and the second can  450  may be coupled to an upper portion and a lower portion of the rotor assembly. In this case, the protruding parts  452  of the second can  450  may be disposed outside the magnets  420  to face the magnets  420 . 
     As illustrated in  FIG.  9 B , the protruding part  452  of the second can  450  may pass through and coupled to the hole  441  of the first can  440 . In this case, since the length of the protruding part  452  may be greater than the length of the rotor core  410  in the axial direction, an end portion of the protruding part  452  coupled to the hole  441  may be disposed to be exposed from the first can  440 . 
     As illustrated in  FIG.  9 C , the end portion of the protruding part  452  passing through the hole  441  may be bent to fix the first can  440 . 
     Accordingly, in the motor  1 , through the process illustrated in  FIGS.  9 A,  9 B, and  9 C , the can  430  can be fixedly coupled to the rotor assembly. Accordingly, separation of the magnet  420  can be inhibited by the can  430 . 
     The shaft  500  may be disposed in the housing  100  to be rotatable due to the bearing B. In addition, the shaft  500  may rotate in conjunction with rotation of the rotor  400 . 
     In addition, the shaft  500  may be coupled to the hole formed in a central portion of the rotor core  410  in a press-fit manner. 
     The busbar  600  may be disposed above the stator  300 . 
     In addition, the busbar  600  may be electrically connected to the coils  330  of the stator  300 . 
     The busbar  600  may include a busbar body (not shown) and a plurality of terminals (not shown) disposed in the busbar body. In this case, the busbar body may be a molded part formed in an injection molding manner. In addition, each of the terminals may be electrically connected to one of the coils  330  of the stator  300 . 
     The sensor part  700  may detect a current position of the rotor  400  by detecting a magnetic force of sensing magnets installed to operate in conjunction with rotation of the rotor  400  to detect rotation of the shaft  500 . 
     The sensor part  700  may include a sensing magnet assembly  710  and a printed circuit board (PCB)  720 . 
     The sensing magnet assembly  710  is coupled to the shaft  500  to operate in conjunction with the rotor  400  to detect a position of the rotor  400 . In this case, the sensing magnet assembly  710  may include the sensing magnets and a sensing plate. 
     The sensing magnets may include main magnets disposed adjacent to a hole forming an inner circumferential surface thereof in the circumferential direction and sub-magnets formed at an edge thereof. 
     The main magnets may be arranged in the same way as the drive magnets inserted into the rotor  400  of the motor. 
     The sub-magnets may be subdivided further than the main magnets so that the sub-magnets have many poles. Accordingly, a rotation angle may be subdivided and measured more precisely due to the sub-magnets, and thus the motor may be driven more smoothly. 
     The sensing plate may be formed of a disc type metal material. The sensing magnets may be coupled to an upper surface of the sensing plate. In addition, the sensing plate may be coupled to the shaft  500 . In this case, a hole through which the shaft  500  passes may be formed in the sensing plate. 
     A sensor which detects a magnetic force of the sensing magnets may be disposed on the PCB  720 . In this case, the sensor may be provided as a Hall integrated circuit (IC). In addition, the sensor may detect changes in an N-pole and an S-pole of the sensing magnets and generate a sensing signal. Accordingly, the PCB  720  on which the Hall IC is disposed may be referred to as a sensing assembly or position detection device. 
     Second Embodiment 
     A motor  1  according to an embodiment may include a housing  100  having one side at which an opening is formed, a cover  200  disposed on the housing  100 , a stator  300  disposed in the housing  100 , a rotor  1400  disposed inside the stator  300 , and the shaft  500  coupled to the rotor  400 . In addition, the motor  1  may include a busbar  600  disposed above the stator  300  and a sensor part  700  which detects rotation of the rotor  400 . In this case, the rotor  1400  may be a rotor according to the second embodiment and may be referred to as a second rotor. That is, the motor  1  may include the rotor  1400  according to the second embodiment instead of the rotor  400  according to the first embodiment. 
     The rotor  1400  may be disposed outside the shaft  500 . The rotor  1400  rotates due to an electrical interaction with the stator  300 . 
       FIG.  12    is a view illustrating the rotor  1400 . 
     Referring to  FIG.  12   , the rotor  1400  may include rotor teeth  1410 , magnets  1420 , and a first member  1430 . In this case, the rotor teeth  1410  and the first member  1430  may be coupled to form a rotor core. In this case, the magnets  1420  may be radially disposed on the rotor core based on a center C. 
     The plurality of rotor teeth  1410  may be provided. The plurality of rotor teeth  1410  are disposed apart from each other in a circumferential direction. The plurality of rotor teeth  1410  may be formed by stacking a plurality of plates. Alternatively, each of the plurality of rotor teeth  1410  may be formed as a single member. Based on one rotor tooth  1410 , the magnets  1420  may be disposed at two sides of the rotor tooth  1410 . 
     Each of the magnets  1420  may be disposed between a rotor tooth  1410 A and a rotor tooth  1410 B which are adjacent to each other in the circumferential direction. That is, the magnet  1420  may be disposed between two rotor teeth  1410  in the circumferential direction. 
     The first member  1430  is disposed inside the magnets  1420  and coupled to the rotor teeth  1410 . In addition, the first member  1430  is coupled to the shaft  500 . In a radial direction, the rotor teeth  1410  are positioned outside the first member  1430 , and the shaft  500  is positioned inside the first member  1430 . The first member  1430  is formed of a non-magnetic member. This is to inhibit a leakage of a magnetic flux leaking to the shaft  500  through the rotor teeth  1410 . In this case, the first member  1430  may be referred to as a yoke. In addition, the first member  1430  may be formed of a different material from the rotor teeth  1410 . For example, the first member  1430  may be formed of a synthetic resin material which is one of non-magnetic materials. 
       FIG.  13    is a plan view illustrating the rotor tooth  1410 . 
     Referring to  FIG.  13   , the rotor tooth  1410  may include first protrusions  1411  and  1412  protruding inward. In addition, the rotor tooth  1410  may include side surfaces  1414 . The first protrusions  1411  and  1412  are for coupling with the first member  1430 . In addition, the side surfaces  1414  are for fixing the magnets  1420  by being in contact with the magnets  1420 . 
     The first protrusions  1411  and  1412  may include a 1-1 protrusion  1411  and a 1-2 protrusion  1412 . 
     The 1-1 protrusion  1411  is connected to the side surfaces  1414 . 
     The 1-2 protrusion  1412  protrudes inward from the 1-1 protrusion  1411 . A width W 2  of the 1-2 protrusion  1412  is greater than a width W 1  of the 1-1 protrusion  1411 . This is to increases a coupling force between the rotor tooth  1410  and the first member  1430 . Accordingly, this is a structure for inhibiting the rotor tooth  1410  from being separated from the first member  1430  in the radial direction. When viewed in an axial direction, the 1-1 protrusion  1411  and the 1-2 protrusion  1412  may be formed in quadrangular shapes. As illustrated in.  FIG.  13   , the first protrusions  1411  and  1412  may be formed in a “T” shape. 
     The rotor tooth  1410  may include third protrusions  1413 . The third protrusions  1413  may be disposed at an outer side the rotor tooth  1410  and disposed to protrude further than the side surfaces  1414 . The third protrusions  1413  restrict an outer surface of the magnet  1420  in the radial direction to inhibit the magnet  1420  from being separated from the rotor tooth  1410  in the radial direction. However, when the first can  440  and the second can  450  according to the first embodiment are applied, the third protrusions  1413  may be removed. 
       FIG.  14    is a plan view illustrating the first member  1430 . 
     The first member  1430  of  FIG.  14    is a member to be connected to the rotor tooth  1410  and the shaft  500 . Particularly, the first member  1430  is formed of a non-magnetic material such as a resin to inhibit a magnetic flux from leaking to the shaft through the rotor tooth  1410 . 
     The first member  1430  may be a hollow member. The first member  1430  may include an outer circumferential surface  1431 , an inner circumferential surface  1432 , a first grooves  1433 , and second grooves  1434 . The outer circumferential surface  1431  is in contact with the magnet  1420 . The inner circumferential surface  1432  may be in contact with the shaft  500 . The first grooves  1433  and the second grooves  1434  are for coupling between the rotor teeth  1410  and the first member  1430 . The first grooves  1433  and the second grooves  1434  are positioned between the outer circumferential surface  1431  and the inner circumferential surface  1432  in the radial direction. 
     The first grooves  1433  and the second grooves  1434  are disposed to communicate with each other. The first grooves  1433  are formed inward from the outer circumferential surface  1431 , and the second grooves  1434  is disposed inward from the first grooves  1433 . For example, the second grooves  1434  may be formed inside the first grooves  1433  to communicate with the first grooves  1433 . 
       FIG.  15    is a plan view illustrating the first groove  1433  and the second groove  1434  of the first member  1430 . 
     Referring to  FIG.  15   , the second groove  1434  may be disposed further inward than the first groove  1433 . A width W 4  of the second groove  1434  may be greater than a width W 3  of the first groove  1433 . This is a structure for inhibiting the rotor tooth  1410  from being separated from the first member  1430  in the radial direction while increasing a coupling force between the rotor tooth  1410  and the first member  1430 . In this case, the width W 3  of the first groove  1433  and the width W 4  of the second groove  1434  are widths in consideration of sizes of the first protrusions  1411  and  1412  of the rotor tooth  1410  and second protrusions  1435 . 
     When the rotor tooth  1410  is installed in the first member  1430 , the first protrusions  1411  and  1412  are positioned in the first groove  1433 , and the second protrusions  1435  are disposed in the second groove  1434 . When viewed in the axial direction, the first groove  1433  and the second groove  1434  may be formed in quadrangular shapes. 
     The second groove  1434  may include first surfaces  1434   a  and  1434   b  and second surfaces  1434   c  and  1434   d  disposed in opposite directions. 
     The first surfaces  1434   a  and  1434   b  may include a 1-1 surface  1434   a  and a 1-2 surface  1434   b  adjacent to each other. In addition, the second surfaces  1434   c  and  1434   d  may include a 2-1 surface  1434   c  and a 2-2 surface  1434   d  adjacent to each other. The 1-1 surface  1434   a  and the 2-1 surface  1434   c  are disposed to face each other. The 1-2 surface  1434   b  and the 2-2 surface  1434   d  are disposed to face each other. The 1-1 surface  1434   a  is connected to the first groove  1433 . The 1-2 surface  1434   b  may be connected to the 2-1 surface  1434   c . The 2-2 surface  1434   d  may be connected to the 1-1 surface  1434   a.    
     The plurality of second protrusions  1435  are disposed on the 2-1 surface  1434   c . The second protrusions  1435  are in contact with the 1-2 protrusion  1412  inserted into the second groove  1434 . The second protrusions  1435  may include curved surfaces. Curved portions of the second protrusions  1435  may be in contact with the 1-2 protrusion  1412  of the rotor tooth  1410 . For example, the 1-2 protrusion  1412  may be in line contact with the second surfaces  1434   c  and  1434   d  through the curved portions of the second protrusions  1435  in the axial direction. When the rotor tooth  1410  is coupled to the first member  1430 , The first protrusions  1411  and  1412  are inserted along the first groove  1433  and the second groove  1434  in the axial direction. In this case, an inner surface of the 1-2 protrusion  1412  of the rotor tooth  1410  is in contact with the second protrusions  1435  disposed in the second groove  1434 , and on outer surface of the 1-2 protrusion  1412  may be in surface contact with the 1-1 surface  1434   a  of the second groove  1434 . 
       FIG.  16    is a view illustrating a modified example of a second groove  1434  of a first member  1430 . 
     Referring to  FIG.  16   , a plurality of second protrusions  1435  may be disposed only on a 1-1 surface  1434   a . First protrusions  1411  and  1412  are inserted along a first groove  1433  and the second groove  1434  in an axial direction, an outer surface of a 1-2 protrusion  1412  of rotor tooth  1410  may be in contact with the second protrusions  1435  disposed in the second groove  1434 , and an inner surface of the 1-2 protrusion  1412  may be in surface contact with a 2-1 surface  1434   c  of the second groove  1434 . 
       FIG.  17    is a view illustrating anther modified example of a second groove  1434   f  a first member  1430 . 
     Referring to  FIG.  17   , a plurality of second protrusions  1435  may be disposed on a 1-2 surface  1434   b  and a 2-2 surface  1434   d . When first protrusions  1411  and  1412  are inserted along a first groove  1433  and a second groove  1434  in an axial direction, a side surface of the 1-2 protrusion  1412  of a rotor tooth  1410  may be in contact with the second protrusions  1435  disposed in the second groove  1434 , and an outer surface of the 1-2 protrusion  1412  may be in surface contact with a 1-1 surface  1434   a  of the second groove  1434 , and an inner surface of the 1-2 protrusion  1412  may be in surface contact with a 2-1 surface  1434   c  of the second groove  1434 . 
       FIG.  18    is a view illustrating a state in which the first protrusions  1411  and  1423  of the rotor tooth is coupled to the first groove  1433  and the second groove  1434  of the first member  1430   
     Referring to  FIG.  18   , when the rotor tooth  1410  is coupled to the first member  1430 , and when the first protrusions  1411  and  1412  is inserted along the first groove  1433  and the second groove  1434  in the axial direction, inner surfaces of the first protrusions  1411  and  1412  form contact regions S1 with the 2-1 surface  1434   c  of the second groove  1434  and non-contact regions S2. The contact regions S1 are regions in which the second protrusions  1435  disposed on the 2-1 surface  1434   c  of the second groove  1434  are disposed, and the non-contact regions S2 are regions in which the second protrusions  1435  are not present. In the non-contact regions S2, spaces are formed between the first protrusions  1411  and  1412  of the rotor tooth  1410  and the second groove  1434  due to the second protrusions  1435 . As illustrated in  FIG.  18   , since the 1-2 protrusion  1412  and the 2-1 surface  1434   c  are disposed apart from each other due to the second protrusions  1435 , the spaces may be formed between the 1-2 protrusion  1412  and the 2-1 surface  1434   c  due to the second protrusions  1435 . In this case, the contact regions S1 may be referred to as first regions, and the non-contact regions S2 may be referred to as second regions. 
     Due to the spaces, the 1-2 protrusion  1412  of the rotor tooth  1410  is easily inserted into the second groove  1434 . In addition. In a state in which outer surfaces and side surfaces of the first protrusions  1411  and  1412  are in surface contact with the 1-1 surface  1434   a , the 1-2 surface  1434   b , and the 2-2 surface  1434   d , since the second protrusions  1435  press the 1-2 protrusion  1412  of the rotor tooth  1410 , there is an advantage of inhibiting the rotor tooth  1410  from being shaken. In addition, in a state in which the rotor tooth  1410  is coupled to the first member  1430 , the plurality of second protrusions  1435  has an advantage of inhibiting the rotor tooth  1410  from being shaken due to a gap between the second groove  1434  and the 1-2 protrusion  1412 . 
     When viewed in the axial direction, corner portions  1412   a  of the 1-2 protrusion  1412  of the rotor tooth  1410  may be formed in round shapes. The round shape may induce the 1-2 protrusion  1412  of the rotor tooth  1410  to be easily inserted into the second groove  1434 . In a state in which the rotor tooth  1410  is inserted into the first member  1430 , the second protrusions  1435  inhibit the rotor tooth  1410  from being shaken. 
     Since the first protrusions  1411  and  1412  of the rotor tooth  1410  are disposed in the first groove  1433  and the second groove  1434 , the first protrusions  1411  and  1412  and the first member  1430  form an overlap region in the circumferential direction. Since the width W 2  of the 1-2 protrusion  1412  of the rotor tooth  1410  is greater than the width W 3  of the first groove  1433 , the rotor tooth  1410  is inhibited from being escaped from the first member  1430  in the radial direction. 
       FIG.  19    is a view illustrating a state in which the magnet  1420  and the first member  1430  are in contact with each other. 
     Referring to  FIG.  19   , an inner surface  1421  of the magnet  1420  is in contact with the outer circumferential surface  1431  of the first member  1430 . In this case, the inner surface of the magnet  1420  is a surface facing the shaft  500 . Since a part of the inner surface  1421  of the magnet  1420  is in contact with the outer circumferential surface  1431  of the first member  1430 , spaces “G” as in  FIG.  19    may be formed. Accordingly, the other part of the inner surface of the magnet  1420  may be disposed apart from the outer circumferential surface  1431  of the first member  1430 . For example, the inner surface of the magnet  1420  may be in line contact with the outer circumferential surface  1431  of the first member  1430 . Accordingly, there is an advantage of improving a coupling force and assemblability of the magnet  1420 . 
     An outer surface  1422  of the magnet  1420  may be fixed by the third protrusions  1413  of the rotor tooth  1410 . In this case, the outer surface  1422  of the magnet  1420  is a surface facing the stator  300 . For example, each of the third protrusions  1413  may support a part of the outer surface  1422  of the magnet  1420  to inhibit the magnet  1420  from being separated. 
     In this case, an example of the rotor  1400  in which the third protrusions  1413  are formed on the rotor tooth  1410  is described, but the present invention is not necessarily limited thereto. For example, when the first can  440  and the second can  450  according to the first embodiment are applied to the rotor  1400 , the third protrusions  1413  may be removed from the rotor tooth  1410 . That is, even when the third protrusions  1413  are not formed on the rotor  1400 , due to the first can  440  and the second can  450  which are coupled to the rotor  1400 , the magnet  1420  can be inhibited from being separated. 
     While the present invention has been described above with reference to exemplary embodiments, it may be understood by those skilled in the art that various modifications and changes of the present invention may be made within a range not departing from the spirit and scope of the present invention defined by the appended claims. 
     
       
         
           
               
             
               
                   
               
               
                 [Reference Numerals] 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 1: MOTOR 
                 100: HOUSING 
               
               
                   
                 200: COVER 
                 300: STATOR 
               
               
                   
                 400, 1400: ROTOR 
                 500: SHAFT 
               
               
                   
                 600: BUSBAR 
                 700: SENSOR PART