electric motor

Abstract

The present application provides a kind of motor.The motor based on the exampled embodiment of the present application is used to make the linear reciprocating movement of object along the rod with predetermined length, comprising: shell;Rotor part, rotatably assembled in the inside of the shell by bearing, comprising: rotor shaft, combined with the rod shaft, linear reciprocating movement along the rod when rotating;And multiple magnets, are arranged along the circumference of the rotor shaft;And stator part, comprising: closed loop shape yoke part, is built-in in the shell in the manner of surrounding the rotor part around;At least one stator core, comprising multiple slot parts extending from the yoke part to the rotor side;And coil, is wound in at least one slot part in the multiple slot parts, the stator core comprises multiple 1st slot part wound with coil and multiple 2nd slot part without winding with coil, the multiple 1st slot part is arranged to surround the circular arc part corresponding to θ angle in the whole circumference of imaginary circle connecting the end of the multiple 1st slot part and the multiple 2nd slot part, and the multiple 2nd slot part is arranged to surround the circular arc part corresponding to 2 π-θ angle in the whole circumference of the imaginary circle.

Description

TECHNICAL FIELD

[0001] The present application relates to an electric motor. BACKGROUND

[0002] Generally, for a seat of an automobile, a backrest is adjusted or a position is changed by electric operation of a motor.

[0003] Such a seat is called an electric seat or a power adjustment seat, and a motor for driving the electric seat or the power adjustment seat is called a seat motor.

[0004] Recently, a trend of automobile-related technology is as follows: technology related to a hybrid vehicle or an electric vehicle is being developed, and energy efficiency is being improved by realizing weight reduction and size reduction of each component of an automobile.

[0005] Therefore, in correspondence with the trend of weight reduction and size reduction of the seat motor, development of a seat motor capable of effectively utilizing a space while maintaining the size of a conventional seat motor is required. SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] The present application has been made in view of the above problems, and aims to provide an electric motor capable of effectively utilizing a space while maintaining the overall size of a motor.

[0008] TECHNICAL SOLUTION

[0009] To solve the above problem, the present application provides an electric motor for linearly reciprocating a subject along a rod having a predetermined length, including: a housing; a rotor portion rotatably fitted inside the housing by a bearing, including: a rotor shaft combined with the rod shaft to linearly reciprocate along the rod when rotating; and a plurality of magnets provided along a circumferential direction of the rotor shaft; and a stator portion including: a yoke portion in a closed loop shape, embedded in the housing so as to surround the rotor portion; at least one stator core including a plurality of slot portions extending from the yoke portion toward the rotor portion; and a coil wound around at least one slot portion of the plurality of slot portions, the stator core including a plurality of first slot portions around which the coil is wound and a plurality of second slot portions around which the coil is not wound, the plurality of first slot portions being arranged to surround a circular arc portion corresponding to a θ angle among a whole circumference of an imaginary circle connecting end portions of the plurality of first slot portions and the plurality of second slot portions, and the plurality of second slot portions being arranged to surround a circular arc portion corresponding to a 2π-θ angle among the whole circumference of the imaginary circle.

[0010] In addition, the slot portion can include: a tooth portion extending from the yoke portion by a predetermined length; and a shoe portion formed at an end portion of the tooth portion, and the tooth portion of the first slot portion can be formed to have a relatively longer length than the tooth portion of the second slot portion.

[0011] In this case, some of the plurality of first slot portions can be formed of teeth having a first length, and the remaining first slot portions can be formed of teeth having a length shorter than the first length. The first slot portion including the teeth having the first length can be disposed between the first slot portions including the teeth having the length shorter than the first length.

[0012] In addition, the first slot portion including the teeth having the first length and the plurality of second slot portions can be disposed on opposite sides with reference to the center point of the imaginary circle.

[0013] In addition, the plurality of first slot portions can include a plurality of first phase portions having a first phase when a power source is applied, and a plurality of second phase portions having a second phase different from the first phase. The total number of turns of coils wound around the plurality of first phase portions and the total number of turns of coils wound around the plurality of second phase portions can be the same number of turns. At this time, in the plurality of first phase portions, the total number of turns of coils wound around each of the first phase portions can be different numbers of turns.

[0014] In addition, the plurality of second slot portions can have phases corresponding to the plurality of first slot portions when a power source is applied. For example, when the plurality of first slot portions are configured to have three phases, the plurality of second slot portions can also be configured to have three phases corresponding to the three phases.

[0015] In addition, the stator core can be disposed such that the plurality of second slot portions are located near a lower surface of the housing inside the housing, and the object can be fixed to an upper surface of the housing.

[0016] In addition, the rotor shaft can include a first rotor shaft combined with the rod shaft to linearly reciprocate along the rod when rotating, and a second rotor shaft combined with the first rotor shaft and having a plurality of magnets disposed in a circumferential direction.

[0017] In addition, the stator portion can include a plurality of stator cores stacked in a length direction of the rod such that one surface of each of the stator cores faces another surface of an adjacent stator core. The plurality of stator cores can be integrated by an insulating member.

[0018] In addition, the rotor shaft can be disposed eccentrically inside the housing.

[0019] In addition, the object can be an electric seat of a vehicle. That is, the electric motor can be used as a driving source for reciprocating the electric seat of the vehicle.

[0020] Effects of Invention

[0021] According to the present application, the position of the rotor portion to which the lead screw is coupled is biased to one side, thereby effectively utilizing the space while maintaining the overall size of the motor. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a view showing an electric motor of an embodiment of the present application,

[0023] Figure 2 is a sectional view of the A-A direction in a state in which the coil is omitted, Figure 1

[0024] Figure 3 is a sectional view of the B-B direction in a state in which the coil is omitted, Figure 1

[0025] Figure 4 is a front view of the Figure 1

[0026] Figure 5 is a view showing a state in which the coil is wound in the Figure 4 Figure 4

[0027] Figure 6 is a view showing a state in which an insulating member applicable to the electric motor of an embodiment of the present application is separated from a stator core, and

[0028] Figure 7 is a view showing a state in which the electric motor of an embodiment of the present application is coupled to a lead screw.

[0029] REFERENCE NUMERALS

[0030] 100: electric motor 102a, 102b: bearing

[0031] 110: housing 112: casing

[0032] 114a, 114b: cover portion 116a, 116b: opening portion

[0033] 118: fastening member 120: rotor portion

[0034] 122: rotor shaft 122a: 1st rotor shaft

[0035] 122b: 2nd rotor shaft 124: magnet

[0036] 130: stator portion 132: stator core

[0037] 133: yoke portion 134: slot portion

[0038] 134a: tooth portion 134b: shoe portion ​​​​​

[0039] 135, 135', 135": 1st groove portion 135a: 1st phase portion

[0040] 135b: 2nd phase portion 135c: 3rd phase portion

[0041] 136: 2nd groove portion 136a: 1st phase portion

[0042] 136b: 2nd phase portion 136c: 3rd phase portion

[0043] 137: coil 138: 1st insulating member

[0044] 138a: main body 138b: leg portion

[0045] 139: 2nd insulating member 139a: main body

[0046] 139b: leg portion 140: circuit substrate DETAILED DESCRIPTION

[0047] Hereinafter, an embodiment of the present application will be described in detail with reference to the accompanying drawings, in a manner that can be easily implemented by those skilled in the art. The present application can be implemented in various different ways, and is not limited to the embodiment described here. In order to clearly describe the present application, portions unrelated to the description are omitted in the accompanying drawings, and the same reference numerals are attached to the same or similar constituent elements throughout the specification.

[0048] The motor 100 of an embodiment of the present application can be used as a driving source that moves an object (not shown) linearly to and from along a rod 10 having a predetermined length.

[0049] As an example, as shown in FIG. 1, the motor 100 of an embodiment of the present application can be provided on the side of the rod 10 having a predetermined length, and can move to and from along the length direction of the rod 10 by performing relative movement when a power source is applied. Figure 7

[0050] Here, the rod 10 can be a well-known lead screw provided on the floor of a vehicle's passenger space in order to provide a motorized seat in the passenger space, and the object can be the motorized seat.

[0051] That is, the motorized seat can be fixed to one side of the motor 100 of an embodiment of the present application, and can move to and from along the length direction of the lead screw by the movement of the motor 100 moving to and from along the lead screw when the motor 100 is driven.

[0052] ​However, the use of the motor 100 of an embodiment of the present application is not limited to this, and can be used without limitation as long as it is used as a driving source for moving an object to and fro along the length direction of the rod 10 having a predetermined length.

[0053] As shown in Figures 1 to 5 This motor 100 of an embodiment of the present application includes a housing 110, a rotor portion 120, and a stator portion 130.

[0054] The housing 110 can accommodate the rotor portion 120 and the stator portion 130 inside, and can be coupled to the object on one side.

[0055] The housing 110 as described above can be formed with at least one opening portion 116a, 116b to allow the rod 10 to be inserted inside and coupled to the rotor portion 120.

[0056] As an example, the opening portion 116a, 116b can be formed in a pair on both sides of the housing 110, and can be formed at positions corresponding to the end portions of the rotor portion 120.

[0057] Thus, the rod 10 can pass through the inside of the housing 110 along the length direction through the pair of opening portions 116a, 116b, and can be coupled to the rotor portion 120.

[0058] At this time, the housing 110 can be formed of one part, but can also be a coupling body in which a plurality of parts are coupled to each other.

[0059] As an example, the housing 110 can include a case 112 having both end portions open to accommodate the rotor portion 120 and the stator core 132 inside, and a pair of cover portions 114a, 114b detachably coupled to both end portion sides of the case 112 through fastening members 118.

[0060] In addition, a circuit substrate 140 for controlling the driving of the rotor portion 120 and the stator portion 130 can be built in the inside of the housing 110.

[0061] The rotor portion 120 can be rotatably fitted inside the housing 110 through at least one bearing 102a, 102b.

[0062] The rotor portion 120 as described above can be coupled to the rod 10 passing through the housing 110 through the opening portion 116a, 116b, and can move along the rod 10 when rotating.

[0063] Thus, the motor 100 of an embodiment of the present application can perform linear to and fro movement along the rod 10 through the rotor portion 120 when the rotor portion 120 rotates.

[0064] To this end, the rotor part 120 can include a hollow rotor shaft 122 combined with the rod 10 shaft to move linearly to and from along the rod 10 when rotating, and a plurality of magnets 124 provided along an outer circumferential surface of the rotor shaft 122.

[0065] The rotor part 120 as described above can rotate by interaction with a magnetic field generated from the coil 137 when a current is supplied to the coil 137 wound on the stator part 130 side.

[0066] At this time, the rotor part 120 can be configured such that the rotor shaft 122 is located eccentrically inside the housing 110.

[0067] That is, as shown in FIG. 1, the rotor shaft 122 can be configured inside the housing 110 in a manner of being located eccentrically from the center of the housing 110. Figure 5 Accordingly, in the motor 100 of an embodiment of the present application, the rotor shaft 122 can be located close to the lower surface of the upper and lower surfaces of the housing 110.

[0068] Here, the upper surface of the housing 110 can be a top surface of the housing 110, and the lower surface of the housing 110 can be a bottom surface of the housing 110.

[0069] Figure 5 In this case, an object such as an electrically powered seat can be combined in a manner of being located on the upper surface side of the housing 110, and the rotor shaft 122 can be located close to the floor surface of the vehicle passenger space. Figure 5 Accordingly, in the case where the rod 10 passes through the housing 110 and is combined with the rotor shaft 122, the length from the rotor shaft 122 combined with the rod 10 to the lower surface of the housing 110 can be minimized.

[0070] Accordingly, even if the rod 10 guiding the movement of the object is located close to the floor surface of the vehicle passenger space, so that there is not enough space between the floor surface of the vehicle passenger space and the lower surface of the housing 110, the motor 100 of an embodiment of the present application can minimize the length of the housing 110 protruding downward from the rod 10, so that it can be connected with the rod 10 using a narrow space without contacting the floor surface of the vehicle passenger space, and can smoothly move to and from along the rod 10.

[0071] Accordingly, even if the rod 10 guiding the movement of the object is located close to the floor surface of the vehicle passenger space, so that there is not enough space between the floor surface of the vehicle passenger space and the lower surface of the housing 110, the motor 100 of an embodiment of the present application can minimize the length of the housing 110 protruding downward from the rod 10, so that it can be connected with the rod 10 using a narrow space without contacting the floor surface of the vehicle passenger space, and can smoothly move to and from along the rod 10.

[0072] Accordingly, even if the rod 10 guiding the movement of the object is located close to the floor surface of the vehicle passenger space, so that there is not enough space between the floor surface of the vehicle passenger space and the lower surface of the housing 110, the motor 100 of an embodiment of the present application can minimize the length of the housing 110 protruding downward from the rod 10, so that it can be connected with the rod 10 using a narrow space without contacting the floor surface of the vehicle passenger space, and can smoothly move to and from along the rod 10.

[0073] ​At this time, although the rotor shaft 122 is connected to the rod 10 shaft as a whole, it is also possible that only a portion of its total length is connected to the rod 10 shaft.

[0074] As an example, the rotor shaft 122 may include: a hollow first rotor shaft 122a, which is axially connected to the rod 10 and moves linearly back and forth along the rod 10 during rotation; and a hollow second rotor shaft 122b, which is axially connected to the first rotor shaft 122a and has a plurality of magnets 124 disposed along its outer circumferential surface.

[0075] In this case, although the rod 10 is coupled to the first rotor shaft 122a, it can easily pass through the interior of the second rotor shaft 122b. As a non-limiting example, the first rotor shaft 122a can be a known lead screw nut, and the rod 10 can be a known lead screw.

[0076] Therefore, when the first rotor shaft 122a rotates, it can move forward and backward along the lead screw by screw movement, and only a portion of the total length of the rotor shaft 122 is connected to the shaft of the rod 10, thereby reducing friction and reducing the power consumption for driving.

[0077] In this invention, although a screw connection is illustrated for the shaft connection between the rod 10 and the rotor shaft 122, it is not limited to this. Any shaft connection that allows the rod 10 to move back and forth along its length direction by rotation can be applied to any known shaft connection.

[0078] The stator portion 130 can be configured to surround the magnet 124 of the rotor portion 120.

[0079] That is, the stator portion 130 can be fixed inside the housing 110 in such a way that it surrounds the rotor portion 120, and can provide a driving force for rotating the rotor portion 120 when power is applied.

[0080] Therefore, the stator portion 130 may include: at least one stator core 132 fixed inside the housing 110; and a coil 137 wound around the stator core 132.

[0081] Specifically, such as Figure 5 As shown, the stator core 132 may include a closed-loop yoke 133 fixed inside the housing 110 and a plurality of slots 134 extending from the yoke 133 toward the rotor 120. Each slot 134 may include a tooth 134a extending from the yoke 133 with a predetermined length and a boot 134b formed at the end of the tooth 134a.

[0082] Here, the yoke 133 may be non-circular, and the plurality of grooves 134 may be formed in the yoke 133 in such a way that an imaginary circle is formed when the ends of the respective boots 134b arranged toward the rotor 120 are connected.

[0083] Therefore, even if the yoke 133 is not circular, the plurality of grooves 134 can be arranged at uniform intervals along the circumference of the rotor 120, so as to surround the entire circumference of the rotor 120.

[0084] like Figure 2 and Figure 3 As shown, the stator portion 130 described above can be a multi-layered stator core 132 containing the yoke portion 133 and the slot portion 134, but it is not limited to this and can also be formed from a single component.

[0085] Furthermore, when multiple stator portions 130 are stacked along the length of the rod 10 with one surface in contact with each other, the multiple stator cores 132 can be integrated by means of insulating members 138 and 139.

[0086] As an example, such as Figure 6 As shown, the insulating components 138 and 139 may include a first insulating component 138 and a second insulating component 139 having corresponding shapes. The first insulating component 138 and the second insulating component 139 are joined together from two directions of the multiple stator cores 132 that are stacked on each other, thereby fixing the multiple stator cores 132.

[0087] In this case, the first insulating member 138 and the second insulating member 139 may include a body 138a and 139a having a closed-loop shape corresponding to the shape of the yoke 133, and a plurality of legs 138b and 139b extending from the body 138a and 139a in the stacking direction of the stator core 132.

[0088] At this time, when the first insulating member 138 and the second insulating member 139 are fastened to each other, the plurality of legs 138b and 139b can be configured to respectively surround the inner periphery of the plurality of slots 134 and yokes 133 provided in each stator core 132.

[0089] That is, the multiple slots 134 constituting each stator core 132 can be surrounded by the legs 138b and 139b of the first insulating member 138 and the second insulating member 139, and the outer periphery of the yoke 133 constituting each stator core 132 can be exposed to the outside without being surrounded by the legs 138b and 139b.

[0090] At this time, the plurality of slot portions 134 can be composed of portions in which the coils 137 are wound and portions in which the coils 137 are not wound, and the lengths of the tooth portions 134a that compose each of the slot portions 134 can be various lengths.

[0091] As an example, the plurality of slot portions 134 can include a plurality of first slot portions 135, 135', 135" in which the coils 137 are wound and a plurality of second slot portions 136 in which the coils 137 are not wound, and the tooth portions 134a of the first slot portions 135, 135', 135" can be formed to have relatively longer lengths than the tooth portions 134a of the second slot portions 136.

[0092] In addition, the plurality of first slot portions 135, 135', 135" can be disposed to surround an arc portion (C1) corresponding to a θ angle of the entire circumference of an imaginary circle that connects the shoe portions 134b of the plurality of first slot portions 135, 135', 135" and the plurality of second slot portions 136, and the plurality of second slot portions 136 can be disposed to surround an arc portion (C2) corresponding to a 2π - θ angle of the entire circumference of the imaginary circle, and the arc portion (C2) corresponding to the 2π - θ angle corresponds to a position corresponding to the lower surface of the housing 110.

[0093] Furthermore, some of the plurality of first slot portions 135, 135', 135" can be formed of tooth portions 134a having a first length, another of the plurality of first slot portions 135' can be formed of tooth portions 134a having a second length that is relatively shorter than the first length, and the remaining first slot portions 135" can be formed of tooth portions 134a having a third length.

[0094] In this case, the first slot portions 135 including the tooth portions 134a having the first length can be disposed between the first slot portions 135' including the tooth portions 134a having the second length, and the first slot portions 135" including the tooth portions 134a having the third length can be disposed between the first slot portions 135' including the tooth portions 134a having the second length and the second slot portions 136.

[0095] That is, the first slot portions 135 including the tooth portions 134a having the first length and the plurality of second slot portions 136 can be disposed on opposite sides with reference to the center point of the imaginary circle.

[0096] In this case, the stator core 132 can be disposed such that the plurality of second slot portions 136 are located near the lower surface of the housing 110 inside the housing 110.

[0097] Thus, as Figure 5As shown, in the motor 100 of an embodiment of the present application, even if the rotor shaft 122 is disposed inside the housing 110 in a manner that is eccentric to the central portion of the housing 110 toward the lower surface side portion, and the yoke portion 133 is formed in a non-circular shape, the plurality of first slot portions 135, 135', 135" and the second slot portion 136 can be disposed so as to surround the entire circumference of the rotor shaft 122, and the second slot portion 136 having a tooth portion 134a that is relatively shorter in length than the tooth portion 134a that constitutes the first slot portion 135, 135', 135" can be disposed in a position close to the lower surface of the housing 110.

[0098] Thus, as described above, in the motor 100 of an embodiment of the present application, the rod 10 that guides the movement of the object is disposed in a position close to the floor surface of the passenger space of the vehicle, so that even if the space between the floor surface of the passenger space of the vehicle and the lower surface of the housing 110 is insufficient, the length of the housing 110 that protrudes downward from the rod 10 can be minimized, so that the rod 10 can be connected using a narrow space without contacting the floor surface of the passenger space of the vehicle, and the movement to and from along the rod 10 can be smoothly performed.

[0099] On the other hand, although the motor 100 of an embodiment of the present application can be implemented by a single-phase motor, it can also be implemented by a multi-phase motor having multiple phases when a power source is applied.

[0100] As an example, the motor 100 of an embodiment of the present application can be a motor in which the plurality of slot portions 134 have three phases.

[0101] Specifically, the plurality of slot portions 134 can have u, v, w three phases when a power source is applied. Here, the 'u phase' can be the 'first phase', the 'v phase' can be the'second phase', and the 'w phase' can be the 'third phase', and the first phase, the second phase, and the third phase can be different phases from each other.

[0102] In this case, both the plurality of first slot portions 135, 135', 135" and the plurality of second slot portions 136 that constitute the plurality of slot portions 134 can be configured to have three phases.

[0103] That is, the plurality of first slot portions 135, 135', 135" described above can include at least two phase portions of a plurality of first phase portions 135a having the first phase described above, a plurality of second phase portions 135b having a second phase different from the first phase described above, and a plurality of third phase portions 135c having a third phase different from the first and second phases described above when power is applied thereto, and the plurality of second slot portions 136 can likewise include at least two phase portions of a first phase portion 136a having the first phase described above, a second phase portion 136b having the second phase described above, and a third phase portion 136c having the third phase described above when power is applied thereto, corresponding to the plurality of first slot portions 135, 135', 135".

[0104] As a non-limiting example, as shown in FIG. 9, in the case of the motor 100 of an embodiment of the present application being configured in a 3:4 structure in which 6 first slot portions 135, 135', 135" in which coils 137 are wound and 3 second slot portions 136 in which coils 137 are not wound constitute 9 slot portions 134, and the number of magnets 124 provided in the rotor portion 120 is 12, two of the 6 first slot portions 135, 135', 135" can be first phase portions 135a, the other two first slot portions can be second phase portions 135b, and the remaining two first slot portions can be third phase portions 135c. In this case, any one of the 3 second slot portions 136 can be a first phase portion 136a, another can be a second phase portion 136b, and the remaining one can be a third phase portion 136c. Figure 5

[0105] At this time, the total number of turns of the coils 137 wound on the first slot portions 135, 135', 135" having the same phase as each other among the plurality of first slot portions 135, 135', 135" can be the same number of turns as each other, and the number of turns of the coils 137 wound on the plurality of first slot portions having the same phase as each other can be different from each other.

[0106] As an example, the total number of turns of the coils 137 wound on the two first phase portions 135a, the total number of turns of the coils 137 wound on the two second phase portions 135b, and the total number of turns of the coils 137 wound on the two third phase portions 135c can be the same as each other, and the number of turns of the coils 137 wound on each of the two first phase portions 135a, the number of turns of the coils 137 wound on each of the two second phase portions 135b, and the number of turns of the coils 137 wound on each of the two third phase portions 135c can be different from each other.

[0107] ​Thus, even if the length of each tooth portion 134a of the plurality of first slot portions 135, 135', 135" is configured to be different from each other as described above, the total number of turns of the coils 137 wound around the first phase portion 135a, the second phase portion 135b, and the third phase portion 135c can be the same number of turns.

[0108] Thus, in the motor 100 of the embodiment of the present application, even if the rotor portion 120 is arranged at a position eccentric to one side inside the housing 110 and the length of the tooth portion 134a constituting each slot portion 134 is made different from each other as described above, the total number of turns of the coils on the first slot portion side having the same phase among the plurality of first slot portions 135, 135', 135" can be made the same number of turns, and the plurality of slot portions 134 can be arranged to surround the entire circumference of the rotor portion 120.

[0109] Thus, even if the motor 100 of the embodiment of the present application is implemented by a multi-phase motor, the total number of turns of the coils constituting each phase can be made the same number of turns, and thus it is possible to prevent a decrease in the efficiency of the motor.

[0110] On the other hand, although the total number of slot portions 134 is nine and the total number of magnets is twelve in the 3:4 structure shown in the drawings, the present application is not limited thereto, and can be changed to any one of various structures in which the ratio of the total number of slot portions to the total number of magnets is 3:2, 9:8, 9:10, or 1:1, and can be implemented by a motor having any one of three phases, a plurality of phases other than three phases, and a single phase.

[0111] Although the embodiment of the present application has been described above, the idea of the present application is not limited to the embodiment given in the present specification, and those skilled in the art who understand the idea of the present application can easily give other embodiments by adding, changing, deleting, or increasing elements, etc. within the same idea, and such embodiments should also be included within the idea of the present application.

Claims

1. An electric motor for linearly reciprocating a subject along a rod having a predetermined length, comprising: a housing; a rotor portion rotatably fitted inside the housing by a bearing, comprising a rotor shaft combined with the rod shaft to linearly reciprocate along the rod upon rotation, and a plurality of magnets disposed along the circumference of the rotor shaft; and a stator portion comprising a yoke portion of a closed loop shape embedded in the housing so as to surround the rotor portion, at least one stator core comprising a plurality of slot portions extending from the yoke portion toward the rotor side, and a coil wound around at least one of the plurality of slot portions, wherein the stator core comprises a plurality of first slot portions around which the coil is wound and a plurality of second slot portions around which the coil is not wound, wherein the plurality of first slot portions are arranged so as to surround an arc portion corresponding to a θ angle of the entire circumference of an imaginary circle connecting the end portions of the plurality of first slot portions and the plurality of second slot portions, and the plurality of second slot portions are arranged so as to surround an arc portion corresponding to a 2π - θ angle of the entire circumference of the imaginary circle, wherein the slot portion comprises a tooth portion extending from the yoke portion by a predetermined length, and a shoe portion formed at the end portion of the tooth portion, wherein the tooth portion of the first slot portion has a relatively longer length than the tooth portion of the second slot portion, wherein a part of the plurality of first slot portions are formed by tooth portions having a first length, and the remaining first slot portions are formed by tooth portions having a length that is relatively shorter than the first length, wherein the first slot portions including the tooth portions having the first length are arranged so as to be positioned between the first slot portions including the tooth portions having a length that is relatively shorter than the first length, wherein the first slot portions including the tooth portions having a length that is relatively shorter than the first length are arranged so as to be positioned between the first slot portions including the tooth portions having the first length and the second slot portions, and wherein the first slot portions including the tooth portions having the first length and the plurality of second slot portions are arranged so as to be positioned on opposite sides with reference to the center point of the imaginary circle.

2. The electric motor according to claim 1, wherein the plurality of first slot portions comprise a plurality of first phase portions having a first phase when a power source is applied, and a plurality of second phase portions having a second phase different from the first phase, and the total number of turns of the coil wound around the plurality of first phase portions and the total number of turns of the coil wound around the plurality of second phase portions are the same number of turns.

3. The electric motor according to claim 2, wherein in the plurality of first phase portions, the total number of turns of the coil wound around each first phase portion is a different number of turns.

4. The electric motor according to claim 2, wherein the plurality of second slot portions have a phase corresponding to the plurality of first slot portions when a power source is applied.

5. The electric motor according to claim 1, wherein the stator core is arranged so that the plurality of second slot portions are positioned near the lower surface of the housing inside the housing, and the subject is fixed to the upper surface of the housing.

6. The electric motor according to claim 1, wherein wherein ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The rotor shaft includes a first rotor shaft combined with the rod shaft to linearly reciprocate along the rod when rotating, and a second rotor shaft combined with the first rotor shaft to be provided with a plurality of magnets in a circumferential direction.

7. The motor according to claim 1, wherein The stator portion includes a plurality of stator cores laminated in a manner that one surface of each stator core faces another stator core along a length direction of the rod, The plurality of stator cores are integrated by an insulating member.

8. The motor according to claim 1, wherein The rotor shaft is disposed at an eccentric position inside the housing.

9. The motor according to claim 1, wherein The object is an electric seat of a vehicle. ​

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