KR20210153360A - Motor - Google Patents

Abstract

The present invention provides a motor which comprises: a housing; a stator disposed in the housing; a rotor disposed in the stator; and a shaft coupled to the rotor. The housing includes a first housing and a second housing. The first housing comprises a first sidewall having a first radius and a second sidewall having a second radius smaller than the first radius. The second housing comprises a third sidewall in contact with the first sidewall and a fourth sidewall in contact with the second sidewall. An outer surface of the first sidewall includes a first coupling means. An inner surface of the third sidewall includes a second coupling means coupled to the first coupling means.

Description

motor {Motor}

The embodiment relates to a motor.

In general, in a motor, the rotor is rotated by electromagnetic interaction between the rotor and the stator. At this time, the shaft connected to the rotor also rotates to generate rotational driving force.

The rotor and stator are housed in a housing. The housing is a hollow cylindrical member. A bearing plate for accommodating the bearing may be disposed at one end of the housing, and a mounting structure connected to an external device may be provided at the other end of the housing.

If die casting, which is formed by injecting molten metal into a mold, is used, a housing including both a bearing plate and a mounting structure can be formed. However, the housing manufactured in this way has a problem in that cracks occur.

Accordingly, the embodiment is intended to solve the above problems, and it is a task to be solved to provide a motor capable of preventing cracks from occurring in the housing.

The problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned here will be clearly understood by those skilled in the art from the following description.

An embodiment includes a housing, a stator disposed in the housing, a rotor disposed in the stator, and a shaft coupled to the rotor, the housing comprising a first housing and a second housing, the first housing includes a first sidewall having a first radius and a second sidewall having a second radius less than the first radius, wherein the second housing has a third sidewall in contact with the first sidewall and a third sidewall in contact with the second sidewall and a fourth sidewall, the outer surface of the first sidewall may include a first coupling means, and the inner surface of the third sidewall may include a second coupling means coupled to the first coupling means.

An embodiment includes a housing, a stator disposed in the housing, a rotor disposed in the stator, and a shaft coupled to the rotor, the housing comprising a first housing and a second housing, the first housing includes a first area having a first radius and a second area having a second radius different from the first radius, wherein the second housing includes a third area contacting the first area and a third area contacting the second area and a fourth region, wherein at least one of the first region and the second region includes a first coupling means, and at least any one of the third region and the fourth region is coupled to the first coupling means It is possible to provide a motor including a second coupling means.

An embodiment includes a housing and a stator disposed within the housing, wherein the housing includes a first housing and a second housing, the first housing includes a first region and a second region, wherein the second housing includes a first region and a second region; The housing includes a third region engaging the first region and a fourth region engaging the second region, the first region including a first groove, and the second region axially comprising the first region a second groove disposed at a different height from the groove, the third region includes a first protrusion corresponding to the first groove, and the fourth region includes a second protrusion corresponding to the second groove A motor can be provided.

An embodiment includes a housing, a stator disposed in the housing, a rotor disposed in the stator, and a shaft coupled to the rotor, the housing comprising a first housing and a second housing, the first housing includes a first area having a first radius and a second area having a second radius smaller than the first radius, wherein the second housing includes a third area coupled to the first area and a third area coupled to the second area and a fourth region, wherein the second housing may provide a motor fixed to the first housing.

The embodiment includes a housing, a stator disposed in the housing, a rotor disposed in the stator, and a shaft coupled to the rotor, wherein the housing includes a first housing and a second housing each including a hole through which the shaft passes. A fifth region including two housings, wherein the first housing and the second housing overlap in an axial direction, and a sixth region and a seventh region in which the first housing and the second housing vertically overlap with respect to the axial direction It is possible to provide a motor including a region, wherein a part of the first housing and a part of the second housing are disposed to overlap in an axial direction in the fifth region.

Advantageously, an inner surface of said first sidewall is in contact with said stator. An inner surface of the second sidewall of the shingi may be in contact with an outer ring of the first bearing supporting the shaft.

Preferably, the plurality of first grooves may be disposed at regular intervals along a circumferential direction of the first housing.

Preferably, the plurality of first grooves may be arranged on a first circumference and a second circumference with respect to an axial center.

Preferably, the first groove disposed on the first circumference and the second groove disposed on the second circumference are displaced from each other along the circumferential direction, A portion and a portion of the second groove disposed on the second circumference may be disposed to overlap in the axial direction.

Preferably, the first groove disposed on the first circumference and the second groove disposed on the second circumference are displaced from each other along the circumferential direction, A portion and a portion of the second groove disposed on the second circumference may be disposed to overlap in the circumferential direction.

Preferably, the first housing includes a fifth sidewall bent from the second sidewall toward the shaft, and the second housing includes a sixth sidewall bent from the fourth sidewall toward the shaft, An outer surface of the fifth sidewall may be in contact with an inner surface of the sixth sidewall.

Preferably, an outer diameter of the first sidewall may be smaller than an outer diameter of the third sidewall, greater than an outer diameter of the fourth sidewall, and an outer diameter of the second sidewall may be smaller than an outer diameter of the fourth sidewall.

Preferably, the first housing may include a third protrusion protruding from an inner surface of the first sidewall, and the third protrusion may be disposed to correspond to the first groove.

Preferably, an inner surface of the third sidewall is in contact with an outer surface of the first sidewall, an inner surface of the fourth sidewall is in contact with a portion of an outer ring of the first bearing, and an inner surface of the second sidewall is in contact with the first It may come into contact with the rest of the outer ring of the bearing.

Preferably, an inner surface of the third sidewall is in contact with an outer surface of the first sidewall, and the fourth sidewall includes an eighth region in contact with an outer surface of the second wall, and a first bearing and an outer surface of the first bearing. It may include a ninth region, and the eighth region and the ninth region may be disposed to have a step difference.

According to the embodiment, the manufacturing method of the area of one end and the other end of the housing and the cylindrical area of the housing accommodating the rotor and the stator is different, thereby providing an advantageous effect of preventing cracks from occurring in the housing.

According to an embodiment, the manufacturing method of the area of one end and the other end of the housing and the cylindrical area of the housing accommodating the rotor and the stator is different, thereby providing an advantageous effect of reducing the manufacturing process.

1 is a side cross-sectional view of a motor according to an embodiment;
Figure 2 is an exploded view of the motor shown in Figure 1,
3 is a perspective view showing a first housing;
4 is a side cross-sectional view of the first housing taken along line AA of FIG. 3 shown in FIG. 3;
5 is a view showing an arrangement of another form of the first groove;
6 is a view showing an arrangement of another form of the first groove;
7 is a view showing an arrangement of another form of the first groove;
8 is a view showing a second housing;
9 is a side cross-sectional view of the second housing taken along line BB of FIG. 8;
10 is a view showing an outer surface of the second housing;
11 is a cross-sectional view showing a state in which the first housing and the second housing are coupled;
12 is a view showing a coupling state of a first housing and a second housing of another type;
13 is a cross-sectional view comparing the dimensions of the first housing and the dimensions of the second housing;
14 is a view showing a first housing in another form;
15 is a cross-sectional view of the first housing taken along CC of FIG. 14;
16 is a view showing a second housing in another form;
17 is a view showing a first housing in another form;
18 is a view showing a second housing in another form;
19 is a side view of the first housing shown in FIG. 17 and the second housing shown in FIG. 18 .

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

However, the technical spirit of the present invention is not limited to some embodiments described, but may be implemented in various different forms, and within the scope of the technical spirit of the present invention, one or more of the components may be selected between the embodiments. It can be combined and substituted for use.

In addition, terms (including technical and scientific terms) used in the embodiments of the present invention may be generally understood by those of ordinary skill in the art to which the present invention belongs, unless specifically defined and described explicitly. It may be interpreted as a meaning, and generally used terms such as terms defined in advance may be interpreted in consideration of the contextual meaning of the related art.

In addition, the terminology used in the embodiments of the present invention is for describing the embodiments and is not intended to limit the present invention.

In this specification, the singular form may also include the plural form unless otherwise specified in the phrase, and when it is described as “at least one (or more than one) of A and (and) B, C”, it is combined with A, B, and C It may include one or more of all possible combinations.

In addition, in describing the components of the embodiment of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used.

These terms are only for distinguishing the component from other components, and are not limited to the essence, order, or order of the component by the term.

And, when it is described that a component is 'connected', 'coupled' or 'connected' to another component, the component is not only directly connected, coupled or connected to the other component, but also with the component It may also include a case of 'connected', 'coupled' or 'connected' due to another element between the other elements.

In addition, when it is described as being formed or disposed on “above (above) or under (below)” of each component, the top (above) or bottom (below) is one as well as when two components are in direct contact with each other. Also includes a case in which another component as described above is formed or disposed between two components. In addition, when expressed as “upper (upper) or lower (lower)”, the meaning of not only the upward direction but also the downward direction based on one component may be included.

1 is a side cross-sectional view of a motor according to an embodiment.

Referring to FIG. 1 , the motor according to the embodiment may include a shaft 100 , a rotor 200 , a stator 300 , a bus bar 400 , a housing 500 , and a bearing plate 600 . . Hereinafter, the term "inside" indicates a direction from the housing 400 toward the shaft 100 which is the center of the motor, and "outside" indicates a direction opposite to the inside, which is a direction from the shaft 100 toward the housing 400 . Hereinafter, the circumferential direction or the radial direction is based on the axial center, respectively. In addition, the height direction of the housing 400 may be a direction parallel to the axial direction.

The shaft 100 may be coupled to the rotor 200 . When electromagnetic interaction occurs between the rotor 200 and the stator 300 through the supply of current, the rotor 200 rotates and the shaft 100 rotates in conjunction therewith. The shaft 100 may be connected to a steering device of a vehicle to transmit power.

The rotor 200 rotates through electrical interaction with the stator 300 . The rotor 200 may be disposed to correspond to the stator 300 and may be disposed inside. The rotor 200 may include a rotor core 210 and a magnet 220 .

The stator 300 is disposed outside the rotor 200 . The stator 300 may include a stator core 310 , an insulator 320 , and a coil 330 . The insulator 320 is seated on the stator core 310 . The coil 330 is mounted on the insulator 320 . The coil 330 causes an electrical interaction with the magnet of the rotor 200 .

The bus bar 400 may be disposed on one side of the stator 300 and connected to the coil 330 .

The housing 500 may be disposed outside the stator 300 . The housing 500 may be a cylindrical member.

The bearing plate 600 covers one open side of the housing 500 . The bearing plate 600 accommodates the second bearing 700 .

The first bearing 700 rotatably supports one end of the shaft 100 .

The second bearing 800 rotatably supports the other end of the shaft.

FIG. 2 is an exploded view of the motor shown in FIG. 1 .

1 and 2 , the housing 500 may be divided into a first housing 510 and a second housing 520 . The first housing 510 accommodates the rotor 200 and the stator 300 . The first housing 510 may be a cylindrical member having one side and the other open. Also, the first bearing 700 may be accommodated in the first housing 510 .

The second housing 520 is where the external device is mounted. The second housing 520 may be coupled to the other end of the first housing 510 .

Here, the molding method of the first housing 510 and the second housing 520 is different. The first housing 510 may be formed through press working. The second housing 520 may be formed by die casting.

The bearing plate 600 may be disposed at one end of the first housing 510 . The bearing plate 600 may be formed by die casting to include the second bearing 800 .

As a cylindrical member, the first housing 510 with a simple structure is molded through press working to fundamentally prevent cracks that may occur due to die casting, and the second housing 520 and bearing plate 600 having a relatively complex structure. can be molded through die casting to secure manufacturing convenience.

Meanwhile, the first housing 510 and the bearing plate 600 may be fastened through a fastening member, and a sealing member 900 may be disposed between the first housing 510 and the bearing plate 600 . The sealing member 900 may be an annular member.

3 is a perspective view of the first housing 510, and FIG. 4 is a side cross-sectional view of the first housing 510 taken along line A-A of FIG. 3 shown.

3 and 4 , the first housing 510 may include a plurality of first grooves 511 . The first groove 511 is disposed on the outer peripheral surface of the first housing 510 . The plurality of first grooves 511 may be disposed at regular intervals along the circumferential direction of the first housing 510 . The first groove 511 may be formed by punching the outer peripheral surface of the first housing 510 . The first groove 511 is for coupling with the second housing 520 . In particular, the first groove 511 engages the first protrusion ( 521 in FIG. 5 ) in the height direction of the housing 500 , the second The second housing 520 is fixed so that the housing 520 does not separate from the first housing 510 .

Although the first groove 511 is shown as a rectangle, the present invention is not limited thereto, and may be implemented in various shapes such as a circle, a square, and an oval.

The first housing 510 may include a first base 513 , a first sidewall 514 , a second sidewall 515 , and a fifth sidewall 516 . The first sidewall 514 is disposed to protrude from the first base 513 to one side, and the second sidewall 515 is disposed to protrude to the other side from the first base 513 . An inner surface of the first sidewall 514 may contact the stator 300 .

The first sidewall 514 may have a first radius R1 with respect to the center C of the first housing 510 , and the second sidewall 515 may have a second radius R2 . The second radius R2 is smaller than the first radius R1 .

The first sidewall 514 may include a first coupling means on the outer surface. The first coupling means may be a first groove 511 disposed on the outer surface of the first sidewall 514 . The first groove 511 may be disposed at an edge of the first sidewall 514 adjacent to the first base 513 .

An inner surface of the second sidewall 515 may contact an outer ring of the first bearing 700 . The second sidewall 515 serves to receive the first bearing 700 .

The fifth sidewall 516 is disposed to be bent inwardly from the second sidewall 515 .

The shape of the first housing 510 may be implemented through press working.

Meanwhile, the first housing 510 may include a flange 517 . The flange 517 is for coupling with the bearing plate 600 . The flange 517 may be disposed to be bent outwardly from one end of the first sidewall 514 . The sealing member (900 in FIG. 1) is disposed in contact with the flange (517).

In a region where the first housing 510 and the second housing 520 contact each other, the first housing 510 may include a first region S1 and a second region S2 . The first region S1 has a first radius R1 based on the axial center C. The second region S2 has a second radius R2 different from the first radius R1 with respect to the axial center C. Referring to FIG. The second radius R2 may be smaller than the first radius R1 .

FIG. 5 is a diagram illustrating another arrangement of the first grooves 511 .

As shown in FIG. 3 , the plurality of first grooves 511 may be disposed on the same circumference of the first housing 510 , but as shown in FIG. 5 , the plurality of first grooves 511 are They may each be arranged on a different circumference. For example, the plurality of first grooves 511 may be separately disposed on the first circumference O1 and the second circumference O2 . In addition, the first groove 511 disposed on the first circumference O1 and the first groove 511 disposed on the second circumference O2 may be displaced from each other so as not to overlap in a direction parallel to the axial direction. have.

6 is a diagram illustrating another arrangement of the first grooves 511 .

Referring to FIG. 6 , the plurality of first grooves 511 are respectively disposed on the first circumference O1 and the second circumference O2 and are disposed to be shifted from each other along the circumferential direction, the first circumference O1 A part of the first groove 511 disposed on the , and a part of the first groove 511 disposed on the second circumference O2 may be disposed to form the overlap region P1 in the circumferential direction.

7 is a view showing another arrangement of the first groove 511 .

Referring to FIG. 7 , the plurality of first grooves 511 are respectively disposed on the first circumference O1 and the second circumference O2 and are disposed to be shifted from each other along the circumferential direction, the first circumference O1 A portion of the first groove 511 disposed on the , and a portion of the first groove 511 disposed on the second circumference O2 are disposed to form an overlap region O2 based on a direction parallel to the axial direction. can be

FIG. 8 is a view showing the second housing 520 , and FIG. 9 is a side cross-sectional view of the second housing 520 taken along line B-B of FIG. 8 .

8 and 9 , the second housing 520 may include a plurality of first protrusions 521 . The first protrusion 521 is disposed on the inner circumferential surface of the second housing 520 . The plurality of first protrusions 521 may be disposed at regular intervals along the circumferential direction of the second housing 520 . The first protrusion 521 may be formed during the die-casting of the second housing 520 . Therefore, the number, position, and shape of the first protrusions 521 may correspond to the first grooves 511 disposed in the first housing 510 .

The second housing 520 may include a second base 523 , a third sidewall 524 , a fourth sidewall 525 , and a sixth sidewall 526 . The third sidewall 524 is disposed to protrude from the second base 523 to one side. The fourth sidewall 525 is disposed to protrude from the second base 523 to the other side. A coupling portion 527 may protrude from an outer circumferential surface of the third sidewall 524 . The coupling part 527 is fastened to an external device.

The second housing 520 may include a third area S3 and a fourth area S4 . The third region S3 is in contact with the first region S1 . The fourth region S4 is in contact with the second region S2 .

10 is a view illustrating an outer surface of the second housing 520 .

9 and 10 , the outer surface of the second housing 520 may include a third groove 528 , a fourth groove 529 , and a fifth groove 501 .

The third groove 528 may be an annular groove disposed along the circumference of the fourth sidewall 525 . The third groove 528 is concavely formed on the outer surface of the second housing 520 to accommodate sealing oil or an O-ring. The outer surface of the second housing 520 is a region to which an external attachment is coupled. Foreign substances flowing into the gap between the external attachment and the outer surface of the housing 520 through the sealing oil or the O-ring accommodated in the third groove 528 may block water.

The fourth groove 529 may be an annular groove disposed along the circumference of the fourth sidewall 525 . A protruding portion of the external attachment may be seated in the fourth groove 529 .

A membrane for ventilation may be disposed in the fifth groove 501 .

11 is a cross-sectional view illustrating a state in which the first housing 510 and the second housing 520 are coupled.

Referring to FIG. 11 , the second housing 520 is molded to cover one end of the first housing 510 through die casting. The inner surface of the second housing 520 is a part of the outer surface of the first housing 510 . contact with

The fifth region S5 is a region where the first housing 510 and the second housing 520 overlap in the axial direction. The sixth region S6 and the seventh region S7 are regions where the first housing 510 and the second housing 520 overlap each other in a direction perpendicular to the axial direction.

In the fifth region S5 , a portion of the first housing 510 and a portion of the second housing 520 may be disposed to overlap in the height direction of the housing 500 through a die casting process. For example. In the process of forming the second housing 520 , the first housing 510 and the second housing 520 are coupled, and at the same time, the first protrusion 521 is disposed in the first groove 511 , and the axis “‡ direction Accordingly, the coupling force between the first housing 510 and the second housing 520 may be greatly increased.

The outer surface of the first sidewall 514 of the first housing 510 and the inner surface of the third wall 524 of the second housing 520 contact each other. The outer surface of the first base 513 of the first housing 510 and the inner surface of the second base 523 of the second housing 520 are in contact. The outer surface of the second sidewall 515 of the first housing 510 and the inner surface of the fourth sidewall 525 of the second housing 520 come into contact with each other. The outer surface of the fifth sidewall 516 is in contact with the inner surface of the sixth sidewall 526 .

12 is a view illustrating a coupling state of the first housing 510 and the second housing 520 in another form.

12 , in the forming process of the second housing 520 , in addition to the first protrusion 521 and the first groove 511 , the second protrusion 522 and the second groove 512 may be additionally disposed. have. The second protrusion 522 and the second groove 512 further increase the coupling force between the first housing 510 and the second housing 520 in the height direction of the housing 500 .

The second protrusion 522 may be disposed on the inner surface of the fourth sidewall 525 of the second housing 520 . The second groove 512 may be disposed on the outer surface of the second sidewall 515 of the first housing 510 . The second protrusion 522 and the second groove 512 may be arranged in plurality or as a single member having an annular shape.

13 is a cross-sectional view comparing the dimensions of the first housing 510 and the dimensions of the second housing 520 .

Referring to FIG. 13 , the outer diameter D1 of the first sidewall 514 should be at least smaller than the outer diameter D3 of the third wall 524 . And the outer diameter D1 of the first sidewall 514 is greater than the outer diameter D4 of the fourth sidewall 525 . The outer diameter D2 of the second sidewall 515 is smaller than the outer diameter D4 of the fourth sidewall 525 .

14 is a view showing a first housing 510 in another form, FIG. 15 is a cross-sectional view of the first housing 510 taken along CC of FIG. 10 , and FIG. 16 is a second housing 520 in another form. ) is a diagram showing

14 to 16 , the first housing 510 may include a third protrusion 518 . The third protrusion 518 may be disposed to protrude from the inner surface of the first housing 510 . The position of the third protrusion 518 corresponds to the position of the first groove 511 . The third protrusion 518 may be formed by punching for forming the first groove 511 . The first groove 511 and the third protrusion 518 may be circular. Referring to FIG. 12 , the second housing 520 may include a circular first protrusion 521 . The first protrusion 521 is disposed in the first groove 511 shown in FIG. 10 .

17 is a view showing a first housing 510 in another form, FIG. 18 is a view showing a second housing 520 in another form, and FIG. 19 is the first housing 510 shown in FIG. 17 . and a side view of the second housing 520 illustrated in FIG. 18 .

17 to 19 , the first housing 510 may be formed such that the inner surface of the second sidewall 515 partially covers the outer circumferential surface of the first bearing 700 . In addition, the second housing 520 may be disposed so that the inner surface of the fourth sidewall 525 is stepped. That is, the fourth sidewall 525 includes an eighth region S8 in contact with the outer surface of the second sidewall 515 and a ninth region S9 in contact with the outer surface of the first bearing 700 , The eighth area S8 and the ninth area S9 may be disposed to have a step difference.

The inner surface of the third sidewall 524 is in contact with the outer surface of the first sidewall 514 . The inner surface of the fourth side wall 525 also contacts a portion of the outer ring of the first bearing 700 , and the inner surface of the second side wall 515 is in contact with the remaining portion of the outer ring of the first bearing 700 . Accordingly, the first bearing 700 is fixed together to the first housing 510 and the second housing 520 .

As described above, the motor according to a preferred embodiment of the present invention has been described in detail with reference to the accompanying drawings.

It is to be understood that one embodiment of the present invention described above is illustrative in all respects and not restrictive, and the scope of the present invention will be indicated by the appended claims rather than the foregoing detailed description. And it should be construed that all changes or modifications derived from the meaning and scope of the claims as well as equivalent concepts are included in the scope of the present invention.

100: shaft
200: rotor
300: stator
400: bus bar
500: housing
510: first housing
511: first groove
512: second groove
520: second housing
521: first projection
522: second projection
600: bearing plate
700: first bearing
800: second bearing

Claims (15)

housing;
a stator disposed within the housing;
a rotor disposed within the stator; and
and a shaft coupled to the rotor;
The housing includes a first housing and a second housing,
the first housing comprises a first sidewall having a first radius and a second sidewall having a second radius less than the first radius;
the second housing includes a third sidewall in contact with the first sidewall and a fourth sidewall in contact with the second sidewall;
The outer surface of the first side wall includes a first coupling means,
The inner surface of the third sidewall includes a second coupling means coupled to the first coupling means. housing;
a stator disposed within the housing;
a rotor disposed within the stator; and
and a shaft coupled to the rotor;
The housing includes a first housing and a second housing,
the first housing comprises a first area having a first radius and a second area having a second radius different from the first radius;
the second housing includes a third region in contact with the first region and a fourth region in contact with the second region;
At least one of the first region and the second region includes a first coupling means,
At least one of the third region and the fourth region includes a second coupling means coupled to the first coupling means. housing;
Including; a stator disposed in the housing;
The housing includes a first housing and a second housing,
The first housing includes a first area and a second area,
The second housing includes a third region coupled to the first region and a fourth region coupled to the second region,
The first region includes a first groove,
The second region includes a second groove disposed at a different height from the first groove in the axial direction,
The third region includes a first protrusion corresponding to the first groove,
The fourth region of the motor includes a second protrusion corresponding to the second groove. housing;
a stator disposed within the housing;
a rotor disposed within the stator; and
and a shaft coupled to the rotor;
The housing includes a first housing and a second housing,
the first housing comprises a first area having a first radius and a second area having a second radius smaller than the first radius;
The second housing includes a third region coupled to the first region and a fourth region coupled to the second region,
The second housing is a motor fixed to the first housing. housing;
a stator disposed within the housing;
a rotor disposed within the stator; and
and a shaft coupled to the rotor;
The housing includes a first housing and a second housing each including a hole through which the shaft passes,
a fifth region in which the first housing and the second housing overlap in an axial direction; and a sixth region and a seventh region in which the first housing and the second housing overlap in a vertical direction with respect to the axial direction;
In the fifth region, a part of the first housing and a part of the second housing are disposed to overlap in an axial direction. According to claim 1,
and an inner surface of the first sidewall is in contact with the stator.
The inner surface of the second side wall of the singi is in contact with the outer ring of the first bearing supporting the shaft. 4. The method of claim 3,
A motor in which the plurality of first grooves are disposed at regular intervals along a circumferential direction of the first housing. 8. The method of claim 7,
A motor in which the plurality of first grooves are arranged on a first circumference and a second circumference with respect to the center of the shaft. 9. The method of claim 8,
A first groove disposed on the first circumference and a second groove disposed on the second circumference are disposed to be shifted from each other in a circumferential direction, and a portion of the first groove disposed on the first circumference and the second groove disposed on the first circumference 2 A motor in which a portion of the second groove disposed on the circumference overlaps with respect to the axial direction. 10. The method of claim 9,
A first groove disposed on the first circumference and a second groove disposed on the second circumference are disposed to be shifted from each other in a circumferential direction, and a portion of the first groove disposed on the first circumference and the second groove disposed on the first circumference 2 A motor in which a portion of the second groove disposed on the circumference overlaps with respect to the circumferential direction. According to claim 1,
The first housing includes a fifth sidewall bent from the second sidewall toward the shaft,
The second housing includes a sixth sidewall bent from the fourth sidewall toward the shaft,
A motor in which an outer surface of the fifth sidewall and an inner surface of the sixth sidewall are in contact. According to claim 1,
an outer diameter of the first sidewall is smaller than an outer diameter of the third sidewall and greater than an outer diameter of the fourth sidewall;
an outer diameter of the second sidewall is smaller than an outer diameter of the fourth sidewall. According to claim 1,
The first housing includes a third protrusion protruding from the inner surface of the first sidewall,
The third protrusion is disposed to correspond to the first groove. According to claim 1,
an inner surface of the third sidewall is in contact with an outer surface of the first sidewall;
an inner surface of the fourth sidewall is in contact with a portion of the outer ring of the first bearing,
The inner surface of the second sidewall is in contact with the remaining part of the outer ring of the first bearing. According to claim 1,
an inner surface of the third sidewall is in contact with an outer surface of the first sidewall;
the fourth sidewall includes an eighth region in contact with the outer surface of the second wall and a ninth region in contact with the outer surface of the first bearing;
The eighth region and the ninth region are arranged to have a step difference.

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