Motor

Abstract

The present invention can provide a motor including a stator, a hollow shaft arranged inside the stator, and a magnet arranged on the outer circumferential surface of the shaft, wherein the shaft includes a protrusion that contacts the magnet, and the protrusion includes a first surface that protrudes from the outer circumferential surface of the shaft and a second surface that is concavely arranged on the inner circumferential surface of the shaft.

Description

Technical Field

[0001] The embodiments relate to a motor.

Background Art

[0002] A motor is a device that converts electrical energy into mechanical energy to obtain a rotational force, and is widely used in vehicles, household electronics, industrial equipment, and the like.

[0003] In particular, an electric power steering system (Electronic Power Steering System, hereinafter referred to as EPS) in which the motor is used drives the motor with an electronic control unit according to operating conditions to ensure turning stability and provide a rapid restoring force. As a result, the driver of the vehicle can drive safely.

[0004] The motor includes a shaft and a stator. The shaft can be hollow. The magnet can be attached to the outer peripheral surface of the shaft. At this time, in the case of a hollow shaft, there is a problem that it is difficult to align the position of the magnet. This is because it is difficult to form a guide for aligning the magnet in consideration of the processing process of the hollow shaft. If there is no guide for aligning the magnet on the shaft, when overmolding the magnet, the magnet may shift. Or, when wrapping the magnet with a can or an adhesive member, there is a risk that the magnet will flow.

[0005] On the other hand, an adhesive is used to fix the magnet to the shaft. When using an adhesive, there is a problem that it takes time to cure. And when overmolding the magnet, there may be a problem that the magnet shifts, and it is also difficult to confirm this. Also, in the case of overmolding, there is a difficult problem in securing a gap with the stator because of its thickness.

Summary of the Invention

Problems to be Solved by the Invention

[0006] Therefore, an embodiment is for solving the above-described problems, and an object thereof is to provide a motor capable of aligning and fixing magnets arranged on an outer peripheral surface of a hollow shaft.

[0007] Another object is to provide a motor capable of reducing a gap between a magnet and a stator, simplifying a process, and confirming a position of the magnet.

Means for Solving the Problems

[0008] An embodiment for achieving the above object includes a stator, a hollow shaft arranged inside the stator, and magnets arranged on an outer peripheral surface of the shaft. The shaft includes a plurality of protrusions that contact the magnets. The plurality of protrusions may include a first surface protruding from the outer peripheral surface of the shaft and a second surface recessed and arranged on an inner peripheral surface of the shaft, thereby providing a motor.

[0009] An embodiment includes a stator, a hollow shaft arranged inside the stator, and magnets arranged on an outer peripheral surface of the shaft. The shaft includes a plurality of second holes penetrating inside and outside the shaft, and a plurality of protrusions respectively arranged in the plurality of second holes and at least a part of which protrudes from the outer peripheral surface of the shaft to contact the magnets, thereby providing a motor.

[0010] Preferably, the plurality of protrusions are arranged at intervals along a circumferential direction of the shaft, and a circumferential interval distance between the plurality of protrusions may be greater than or equal to a width of the magnet.

[0011] Preferably, the plurality of protrusions are arranged at intervals along an axial direction of the shaft, and an axial interval distance of the protrusions may be less than or equal to a length of the magnet.

[0012] Preferably, one of the plurality of protrusions is arranged along the axial direction of the shaft, and the axial length of the one protrusion may be greater than 1 / 2 of the length of the magnet.

[0013] Preferably, the first surface and the second surface may each include at least one flat surface.

[0014] Preferably, the first surface may include a curved surface that contacts the magnet.

[0015] Preferably, the height from the outer peripheral surface of the shaft to the outer end of the protrusion based on the radial direction of the shaft may be smaller than the height of the magnet.

[0016] Preferably, the shaft includes a first hole that penetrates the inside and the outside, and the protrusion may extend from the frame of the first hole.

[0017] Preferably, it includes a cover arranged outside the magnet, and the cover may include a groove in which the protrusion is arranged.

[0018] Preferably, threads may be arranged on the side surface of the protrusion and the second hole.

[0019] Preferably, a knurled structure may be arranged on the protrusion.

[0020] An embodiment for achieving the above object includes a stator, a shaft disposed inside the stator, a magnet coupled to the shaft, and a cover disposed outside the magnet. The cover includes a first part and a second part extending from one side of the first part. The inner surface of the magnet contacts the outer surface of the shaft, the inner surface of the magnet contacts the outer surface of the shaft, the outer surface of the magnet contacts the inner surface of the first part, a part of the inner surface of the second part contacts the outer surface of the shaft, and the remaining part is spaced apart from the outer surface of the shaft, and a space may be disposed between the outer surface of the shaft and the inner surface of the second part, providing a motor.

[0021] Preferably, the cover includes a third part extending from the other side of the first part. A part of the inner surface of the third part contacts the outer surface of the shaft, and the remaining part is spaced apart from the outer surface of the shaft, and a space may be disposed between the outer surface of the shaft and the other end surface of the magnet.

[0022] Preferably, the cover includes a plurality of first regions arranged at intervals in the circumferential direction from the axis center. The radial distance from the outer surface of the shaft to the first region may be smaller than the shortest radial distance from the outer surface of the shaft to the outer surface of the magnet.

[0023] Preferably, the magnet includes a first unit magnet and a second unit magnet. The first region is disposed between the first unit magnet and the second unit magnet, and the first region may be arranged along the axial direction.

[0024] Preferably, the cover may include a second region having a multilayer structure in the radial direction centered on the axis.

[0025] Preferably, the cover includes a first layer and a second layer laminated on the first layer in the second region. One edge of the second layer is arranged to be inclined with respect to one edge of the first layer.

[0026] Preferably, the cover may include a third region having different thicknesses in the radial direction around the axis center.

[0027] Preferably, the outer surface of the cover may include a stepped region.

[0028] Preferably, the cover may be a member impregnated with epoxy in fibers.

[0029] Preferably, the shaft includes protrusions that contact the magnet, and the protrusions may be arranged spaced apart from the cover.

Advantages of the Invention

[0030] According to the embodiment, it provides an advantageous effect of easily aligning the magnets arranged on the outer peripheral surface of the hollow shaft.

[0031] According to the embodiment, it provides an advantageous effect of preventing the magnets from flowing when overmolding or covering the magnets with a can.

[0032] According to the embodiment, the protrusions have the advantages that they can be mounted with a small size, the number can be increased, and the position of the magnet can be guided more precisely.

[0033] According to the embodiment, there is an advantage that the protrusions can be easily formed by embossing or punching.

[0034] According to the embodiment, the knurled structure formed on the side surface of the protrusion has the advantage of preventing the magnet from detaching during the process.

[0035] According to the embodiment, by minimizing the thickness of the cover and greatly reducing the gap between the magnet and the stator, there is an advantage of improving the performance of the motor.

[0036] According to the embodiment, since the position of the magnet can be confirmed from the outside of the cover, there is an advantage that defects of the magnet can be easily identified.

[0037] According to the embodiment, when fixing the magnet to the shaft, since no adhesive is used, there is an advantage of reducing the process time.

Brief Description of the Drawings

[0038]

Figure 1

[0039]

Figure 2

[0040]

Figure 3

[0041]

Figure 4

[0042]

Figure 5

[0043]

Figure 6

[0044]

Figure 7

[0045]

Figure 8

[0046]

Figure 9

[0047]

Figure 10

[0048]

Figure 11

[0049]

Figure 12

[0050]

Figure 13

[0051]

Figure 14

[0052]

Figure 15

[0053]

Figure 16

[0054]

Figure 17

[0055]

Figure 18

[0056]

Figure 19

[0057]

Figure 20

[0058]

Figure 21

[0059]

Figure 22

[0060]

Figure 23

[0061]

Figure 24

[0062]

Figure 25

[0063]

Figure 26

[0064]

Figure 27

Embodiments for Carrying Out the Invention

[0065] Hereinafter, with reference to the attached drawings, preferred embodiments of the present invention will be described in detail.

[0066] However, the technical idea of the present invention is not limited to some of the described embodiments, and can be embodied in various different forms. As long as it is within the scope of the technical idea of the present invention, one or more of the components among the embodiments can be selectively combined and replaced for use.

[0067] In addition, terms used in the embodiments of the present invention (including technical and scientific terms) can be interpreted as meanings generally understandable to those with ordinary knowledge in the technical field to which the present invention pertains, unless specifically defined and described otherwise. Terms generally used as defined in a dictionary can be interpreted in consideration of their meanings in the context of the related art.

[0068] Also, the terms used in the embodiments of the present invention are for the purpose of explaining the embodiments and do not limit the present invention.

[0069] In this specification, the singular form may also include the plural form unless otherwise specifically mentioned in the text. When described as "at least one (or one or more) of A, B, and C", it may include one or more of all combinations formed by A, B, and C.

[0070] Also, when explaining the components of the embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. can be used.

[0071] These terms are for distinguishing the components from other components and are not limited to the essence, order, or sequence of the components by these terms.

[0072] And when a component is described as "connected", "coupled", or "joined" to another component, that component includes not only the case where it is directly connected, coupled, or joined to the other component, but also the case where it is "connected", "coupled", or "joined" by another component or other components existing between that component and the other component.

[0073] Also, when described as being formed or disposed "above or below" each component, "above or below" includes not only the case where two components are in direct contact with each other, but also the case where one or more other components are formed or disposed between the two components. Further, when expressed as "above or below", it may include not only the upper direction but also the lower direction with respect to one component.

[0074] FIG. 1 is a drawing showing a motor according to an embodiment.

[0075] Referring to FIG. 1, the motor according to the embodiment may include a shaft 100, a magnet 200, a stator 300, a cover 400, a housing 500, and a bus bar 600. Hereinafter, "inner" means a direction arranged toward the shaft 100 based on the radial direction of the motor, and "outer" means a direction opposite to the inner direction.

[0076] The shaft 100 may be a hollow member with one side open. In the axial direction, both ends of the shaft 100 can be rotatably supported by bearings respectively. The shaft 100 may have portions with different outer diameters divided and arranged along the axial direction.

[0077] The magnet 200 is disposed on the outer peripheral surface of the shaft 100. The magnet 200 rotates in conjunction with the rotation of the shaft 100. There may be a plurality of magnets 200.

[0078] The stator 300 is disposed outside the shaft 100 and the magnet 200. The stator 300 may include a stator core 310, an insulator 320 attached to the stator core 310, and a coil 330 wound around the insulator 320. The coil 330 forms a magnetic field. The stator core 310 may be a single member or a combination of a plurality of divided cores. Also, the stator core 310 may be formed by laminating a plurality of thin steel plates on each other, but is not necessarily limited to this. For example, the stator core 310 may be formed as a single unitary product.

[0079] The cover 400 fixes the magnet 200 to the shaft 100. The cover 400 encloses a part of the region of the magnet 200 and the shaft 100. The cover 400 may be a molded member formed by overmolding, or a can member or an adhesive member that encloses the magnet 200.

[0080] The housing 500 may be disposed outside the stator 300. The housing 500 may be a cylindrical member with an open top. The housing 500 houses the shaft 100, the magnet 200, the stator 300, and the cover 400 inside. And the housing 500 may house a bearing that supports the shaft 100.

[0081] The bus bar 600 is disposed above the stator 300. The bus bar 600 connects the coils 330 wound around the stator 300 core.

[0082] FIG. 2 is a perspective view showing the shaft 100, and FIG. 3 is a side cross-sectional view of the shaft 100 showing the protrusion 110 of the shaft 100.

[0083] The shaft 100 is a hollow member and can be formed by pressing.

[0084] Referring to FIGS. 2 and 3, the shaft 100 includes a plurality of protrusions 110 that contact the magnet 200. The plurality of protrusions 110 are disposed on the outer peripheral surface of the shaft 100. The plurality of protrusions 110 may be spaced apart from each other along the circumferential direction O of the shaft 100. And the plurality of protrusions 110 may be spaced apart from each other along the axial direction X of the shaft 100. These protrusions 110 serve to align and fix the magnet 200 disposed on the outer peripheral surface of the shaft 100.

[0085] The plurality of protrusions 110 include a first surface 111 and a second surface 112. The first surface 111 may protrude from the outer peripheral surface of the shaft 100. The second surface 112 may be recessed and disposed on the inner peripheral surface of the shaft 100.

[0086] The first surface 111 may include a first-1 surface 111a and a first-2 surface 111b. The first-1 surface 111a is a portion protruding from the outer peripheral surface of the shaft 100. The first-2 surface 111b connects the outer peripheral surface of the shaft 100 and the first-1 surface 111a. The first-1 surface 111a may include a flat surface, and the first-2 surface 111b may include a curved surface that contacts the magnet 200. The curved surface of the first-2 surface 111b is in line contact with the side surface of the magnet 200 and guides the magnet 200 to be inserted more smoothly between the protrusions 110. Also, an involute structure is applied to the first-2 surface 111b to enhance the fixing force between the shaft and the magnet.

[0087] The second surface 112 may include a second-1 surface 112a and a second-2 surface 112b. The second-1 surface 112a is a portion formed more recessed than the inner peripheral surface of the shaft 100. The second-2 surface 112b connects the inner peripheral surface of the shaft 100 and the second-1 surface 112a. The second-1 surface 112a may include a flat surface, and the second-2 surface 112b may include a curved surface.

[0088] These first surface 111 and second surface 112 may be formed by embossing performed inside the hollow shaft 100. The distance t2 between the first surface 111 and the second surface 112 may be the same as the thickness t1 of the shaft 100 around the protrusion 110.

[0089] FIG. 4 is a side sectional view of the shaft 100 showing a modified example of the protrusion 110.

[0090] Referring to FIG. 4, as a modified example of the protrusion 110, the first-second surface 111b can be arranged to incline toward the first-first surface 111a. And the second-second surface 112b can be arranged to incline toward the second-first surface 112a. The shape of the side cross section of these protrusions 110 can have approximately a trapezoidal shape. Also, an involute structure is applied to the first-second surface 111b, and the fixing force between the shaft and the magnet can be increased.

[0091] FIG. 5 is a side sectional view of the shaft 100 showing another modified example of the protrusion 110.

[0092] Referring to FIG. 5, a plurality of the protrusions 110 can be arranged along the circumferential direction of the shaft 100, but one protrusion 110 can be arranged along the axial direction of the shaft 100. One protrusion 110 can have the first-first surface 111a and the second-first surface 112a arranged long along the axial direction respectively. Also, an involute structure is applied to the first-second surface 111b, and the fixing force between the shaft and the magnet can be increased. These first surface 111 and second surface 112 can be formed by a beading process performed inside the hollow shaft 100.

[0093] FIGS. 6 and 7 are side sectional views of the shaft 100 showing another modified example of the protrusion 110.

[0094] Referring to FIGS. 6 and 7, the shaft 100 may include a first hole 113 that penetrates the inside and outside of the shaft 100. The first hole 113 may be formed in a quadrilateral shape. The protrusion 110 may extend from the frame of the first hole 113. The side surface of the protrusion 110 may include a plane 114 that contacts the magnet 200. A plurality of these protrusions 110 may be arranged along the circumferential direction of the shaft 100. Also, a plurality of protrusions 110 may be arranged along the axial direction of the shaft 100. Further, among the side surfaces of the protrusion, a knurled structure is applied to the plane 114 that contacts the magnet 200, and the fixing force between the shaft 100 and the magnet 200 can be increased.

[0095] For example, as shown in FIG. 6, the first surface 111 of the protrusion 110 may be arranged to incline downward. And the second surface 112 of the protrusion 110 may also be arranged to incline downward.

[0096] Or, as shown in FIG. 7, the first surface 111 of the protrusion 110 may be arranged to incline upward. And the second surface 112 of the protrusion 110 may also be arranged to incline upward.

[0097] Although the protrusions 110 having various shapes have been exemplified as described above, the present invention is not limited thereto, and it can be deformed into protrusions 110 having various shapes formed by embossing performed inside the shaft 100.

[0098] It is possible to guide and fix the magnet 200 arranged on the shaft 100 via these protrusions 110. Since the magnet 200 is directly guided and fixed to the shaft 100, there is an advantage that the rotor core can be omitted.

[0099] Also, these protrusions 110 can be mounted in a small size, and the number can be significantly increased relatively compared to a general guide structure. Therefore, there is an advantage that the position of the magnet 200 can be guided more precisely.

[0100] In addition, there is an advantage that the protrusion 110 can be easily formed by embossing.

[0101] FIG. 8 is a perspective view showing a shaft 100 with a magnet 200 disposed on its outer peripheral surface.

[0102] Referring to FIG. 8, a plurality of magnets 200 are disposed on the outer peripheral surface of the shaft 100. Based on the circumferential direction of the shaft 100, the magnets 200 are disposed between the protrusions 110. The side surface of the protrusion 110 contacts the side surface of the magnet 200.

[0103] FIG. 9 is a drawing showing the separation distance of the protrusions 110, and FIG. 10 is a drawing showing the size of the magnet 200.

[0104] Referring to FIGS. 9 and 10, the circumferential separation distance W1 of the protrusions 110 can be greater than or equal to the width W2 of the magnet 200. This is for the magnet 200 to be positioned between the protrusions 110 based on the circumferential direction of the shaft 100.

[0105] Also, referring to FIGS. 9 and 10, the axial separation distance L1 of the protrusions 110 can be less than or equal to the length L2 of the magnet 200. This is for at least two protrusions 110 arranged in the same column in the axial direction to guide the magnet 200.

[0106] On the other hand, as shown in FIG. 5, when one protrusion 110 is arranged along the axial direction of the shaft 100, the length L3 of the protrusion 110 may be greater than 1 / 2 of the length L2 of the magnet 200. This is the minimum length of the protrusion 110 that can guide and fix the magnet 200 without the magnet 200 shifting.

[0107] FIG. 11 is a front view of the shaft 100 comparing the height of the protrusion 110 and the height of the magnet 200.

[0108] Referring to FIG. 11, the height H1 from the outer peripheral surface of the shaft 100 to the outer end of the protrusion 110 with reference to the radial direction of the shaft 100 may be smaller than the height H2 of the magnet 200. The height H1 of the protrusion 110 may be based on the width center of the protrusion 110 with reference to the circumferential direction of the shaft 100. And the height H2 of the magnet 200 may be based on the width center of the magnet 200 with reference to the circumferential direction of the shaft 100. This is in consideration of the position of the cover 400 covering the magnet 200. In FIG. 11, the protrusion 110 is illustrated, but in the case of the other-shaped protrusions 120 shown in FIGS. 17 to 19, the height from the outer peripheral surface of the shaft 100 to the outer end of the protrusion 120 may also be smaller than the height H2 of the magnet 200.

[0109] FIG. 12 is a drawing showing the shaft 100 overmolded with the cover 400 disposed thereon, and FIG. 13 is a side cross-sectional view of the shaft 100 shown in FIG. 12.

[0110] Referring to FIGS. 12 and 13, the cover 400 can be a molded member formed by overmolding. These covers 400 include the groove 410 in which the protrusion 110 is disposed. By disposing the protrusion 110 in the groove 410, the bonding force between the cover 400 and the shaft 100 is increased, and the bonding force between the cover 400 and the magnet 200 is also increased.

[0111] FIG. 14 is a drawing showing the protrusions 110 disposed on the upper side and the left and right sides of the magnet 200.

[0112] Referring to FIG. 14, the protrusion 110 may include a first-1 protrusion 110A disposed on the side surface of the magnet 200 and a first-2 protrusion 110B disposed on the upper side of the magnet 200. The first-2 protrusion 110B is disposed on the upper side of the magnet 200 and contacts the upper end of the magnet 200, thereby preventing the magnet 200 from detaching upward from its fixed position.

[0113] FIG. 15 is a drawing showing the protrusions 110 disposed on the lower side and the left and right sides of the magnet 200.

[0114] Referring to FIG. 15, the protrusion 110 may include a first - 1 protrusion 110A disposed on the side surface of the magnet 200 and a first - 3 protrusion 110C disposed on the lower side of the magnet 200. By being disposed on the lower side of the magnet 200 and contacting the lower end of the magnet 200, the first - 3 protrusion 110C can prevent the magnet 200 from detaching downward from its fixed position.

[0115] FIG. 16 is a drawing showing the protrusions 110 disposed on the upper and lower sides of the magnet 200, respectively.

[0116] Referring to FIG. 16, the protrusion 110 may include a first - 1 protrusion 110A disposed on the side surface of the magnet 200, a first - 2 protrusion 110B disposed on the upper side of the magnet 200, and a first - 3 protrusion 110C disposed on the lower side of the magnet 200. By contacting the upper end of the magnet 200, the first - 2 protrusion 110B can prevent the magnet 200 from detaching upward from its fixed position, and by contacting the lower end of the magnet 200, the first - 3 protrusion 110C can prevent the magnet 200 from detaching downward from its fixed position.

[0117] Thus, the protrusion 110 has been exemplified. However, the other - shaped protrusions 120 shown in FIGS. 17 - 19 may also include at least any one of the first - 1 protrusion disposed on the side surface of the magnet 200, the first - 2 protrusion disposed on the upper side of the magnet 200, and the first - 3 protrusion 110C disposed on the lower side of the magnet 200.

[0118] FIG. 17 is a drawing showing a shaft 100 including a protrusion 120 and a second hole 130.

[0119] Referring to FIG. 17, the shaft 100 may include a second hole 130 that penetrates the inside and outside of the shaft 100. A plurality of second holes 130 may be arranged along the circumferential direction of the shaft 100. Also, a plurality of second holes 130 may be arranged along the axial direction of the shaft 100. The plurality of second holes 130 may be formed by punching.

[0120] The protrusion 120 can be respectively arranged in a plurality of second holes 130. The protrusion 120 is arranged such that at least a part thereof protrudes from the outer peripheral surface of the shaft 100 in a state of being inserted into the second hole 130. The protrusion 120 can be made of a plastic resin. The protrusion 120 contacts the magnet 200. Threads can be formed on the contact area between the side surface of the protrusion 120 and the shaft 100 to increase the bonding force between the protrusion 120 and the shaft 100. A knurl structure for increasing the fixing force between the magnet 200 and the shaft 100 can be applied to the portion of the side surface of the protrusion 120 that does not contact the shaft 100.

[0121] FIG. 18 is a perspective view of the shaft 100 including a modified example of the protrusion 120.

[0122] Referring to FIG. 18, a plurality of second holes 130 can be arranged along the circumferential direction, but one long-hole-shaped second hole 130 can be arranged along the axial direction of the shaft 100. Correspondingly, a plurality of protrusions 120 can be arranged along the circumferential direction, but one protrusion 120 can be arranged along the axial direction of the shaft 100. A knurl structure for increasing the fixing force between the magnet 200 and the shaft 100 can be applied to the portion of the side surface of the protrusion 120 that does not contact the shaft 100.

[0123] Referring to FIG. 17, the circumferential separation distance W3 of the protrusions 120 can be greater than or equal to the width W2 of the magnet 200. This is for the magnet 200 to be positioned between the protrusions 120 with respect to the circumferential direction of the shaft 100.

[0124] Also, the axial separation distance L4 of the protrusions 120 can be less than or equal to the length L2 of the magnet 200. This is for at least two protrusions 120 arranged in the same column in the axial direction to guide the magnet 200.

[0125] Referring to FIG. 18, when one protrusion 120 is arranged along the axial direction, the length L5 of the protrusion 110 may be greater than 1 / 2 of the length L2 of the magnet 200. This is the minimum length of the protrusion 120 that can guide and fix the magnet 200 by the protrusion 120 without the magnet 200 shifting.

[0126] FIG. 19 is a side cross-sectional view of the shaft 100 overmolded with the cover 400 disposed thereon.

[0127] Referring to FIG. 19, the cover 400 includes a groove 420 in which the protrusion 120 is arranged. By arranging the protrusion 120 in the groove 420, the bonding force between the cover 400 and the shaft 100 is increased, and the bonding force between the cover 400 and the magnet 200 is also increased.

[0128] FIG. 20 is a drawing showing the shaft with the cover 400 disposed thereon, and FIG. 21 is a drawing showing a state in which the cover 400 wraps the magnet 200 disposed on the outer peripheral surface of the shaft 100.

[0129] Referring to FIGS. 20 and 21, the cover 400 can be an adhesive member that wraps the magnet 200 and fixes it to the shaft 100. For example, the cover 400 can be a member in which a base material (Matrix) is impregnated with reinforcing fibers.

[0130] Such a cover 400 serves as an adhesive sheet for fixing the magnet 200 to the shaft 100 as a semi-cured member. The reinforcing fibers can mainly be carbon fibers, glass fibers, aramid fibers, etc., and the base material can be an epoxy resin, a polyester resin, or a thermoplastic resin. Carbon fibers are characterized by high tensile strength and tensile modulus of elasticity as mechanical properties, and excellent heat resistance and fire resistance as thermal properties. Glass fibers are characterized by high tensile strength and tensile modulus of elasticity as mechanical properties, and a small coefficient of linear expansion as thermal properties. Both carbon fibers and glass fibers are characterized by excellent electrical insulation properties.

[0131] When the shaft 100 rotates with a part of the cover 400 in contact with the shaft 100 and the magnet 200, the cover 400 can naturally wind around the shaft 100 in a shape that wraps the magnet 200, and has the advantages that the process is simple and rapid.

[0132] The cover 400 may include a first part 410 partitioned based on the axial direction, a second part 420, and a third part 430. The second part 420 extends from one side of the first part 410. The third part 430 extends from the other side of the first part 410.

[0133] The first part 410 is a part that covers the magnet 200, and the second part 420 and the third part 430 are parts that contact the shaft 100.

[0134] FIG. 22 is a side sectional view of the shaft 100, the magnet 200, and the cover 400.

[0135] Referring to FIG. 22, the inner surface of the magnet 200 contacts the outer surface of the shaft 100. And the outer surface of the magnet 200 contacts the inner surface 401 of the first part 410. A part of the inner surface 402 of the second part 420 contacts the outer surface of the shaft 100, and the remaining part of the inner surface 402 of the second part 420 is disposed spaced apart from the outer surface of the shaft 100. A space S1 is formed between the outer surface of the shaft 100, one end surface 203 of the magnet 200, and the inner surface 402 of the second part 420.

[0136] Also, a part of the inner surface 403 of the third part 430 contacts the outer surface of the shaft 100, and the remaining part of the inner surface 403 of the third part 430 is disposed spaced apart from the outer surface of the shaft 100. A space S2 is formed between the outer surface of the shaft 100, the other end surface 204 of the magnet 200, and the inner surface 403 of the third part 430.

[0137] FIG. 23 is a plan sectional view of the shaft 100, the magnet 200, and the cover 400.

[0138] Referring to FIG. 23, the cover 400 may include a plurality of first regions A1. The plurality of first regions A1 may be arranged at intervals in the circumferential direction from the axis center. In the first region A1, the radial distance R1 from the outer surface of the shaft 100 to the first region A1 is smaller than the shortest radial distance R2 from the outer surface of the shaft 100 to the outer surface of the magnet 200. The shortest radial distance R2 from the outer surface of the shaft 100 to the outer surface of the magnet 200 may be based on the side end of the outer surface of the magnet 200 in the circumferential direction considering the Bread shape of the outer surface of the magnet 200.

[0139] The first region A1 is arranged between the first unit magnet 200A and the second unit magnet 200B with reference to the circumferential direction. Also, the first region A1 is arranged to be long along the axial direction.

[0140] Since such a first region A1 is distinguishable from other regions of the cover 400 with the naked eye, the arrangement state of the magnet 200 can be confirmed with the naked eye or by video in a state where the cover 400 wraps the magnet 200. Therefore, the operator can easily inspect whether there is any problem with the arrangement of the magnet 200.

[0141] FIG. 24 is a plan sectional view of the shaft 100 and the magnet 200 showing the second region A2 and the third region A3 of the cover 400.

[0142] Referring to FIG. 24, the cover 400 is wound around the shaft 100 so as to form multiple layers. Hereinafter, the region where the cover 400 forms multiple layers with reference to the radial direction is referred to as the second region A2, and the region having a thickness t2 different from the thickness t2 of one region in the radial direction centered on the axis is referred to as the third region A3.

[0143] The cover 400 may include a first layer 400A in the second region A2 and a second layer 400B laminated on the first layer 400A. In the drawings, the first layer 400A and the second layer 400B are illustrated, but the present invention is not limited thereto and may be composed of more layers such as a third layer and a fourth layer. Therefore, the second region A2 may be a region having three or more layers.

[0144] In FIG. 24, the positions of the second region A2 and the third region A3 are illustrated as being the same, but the present invention is not limited thereto, and the positions of the second region A2 and the third region A3 may be different.

[0145] The outer surface of the cover 400 may include a stepped region A4.

[0146] FIG. 25 is a drawing showing the edges E1 and E2 on one side of the cover 400 in the second region A2.

[0147] Referring to FIG. 25, in the second region A2, the edge E2 on one side of any one layer may be arranged to be inclined with respect to the edge E1 on one side of the other layer. Also, in the second region A2, the other edge E4 of any one layer may be arranged to be inclined with respect to the other edge E3 of the other layer. This may be a feature naturally derived in the process of finishing and adhering the tip of the cover 400 after winding the cover 400 around the shaft 100.

[0148] FIG. 26 is a perspective view of a shaft including protrusions, and FIG. 27 is a plan sectional view of the shaft 100 including protrusions and the magnet 200.

[0149] Referring to FIGS. 26 and 27, the shaft 100 includes a plurality of protrusions 110 that come into contact with the magnet 200. The plurality of protrusions 110 are arranged on the outer peripheral surface of the shaft 100. The plurality of protrusions 110 may be arranged at intervals along the circumferential direction of the shaft 100. And the plurality of protrusions 110 may be arranged at intervals along the axial direction X of the shaft 100. These protrusions 110 serve to align and fix the magnet 200 arranged on the outer peripheral surface of the shaft 100. The protrusions may be formed by an embossing process performed inside the hollow shaft 100.

[0150] The protrusions 110 serve to fix the magnet 200 so that it does not shift during the process of the cover 400 enclosing the magnet 200. The protrusions 110 may be arranged at a distance from the cover 400.

[0151] The motor according to one preferred embodiment of the present invention has been specifically described with reference to the accompanying drawings.

[0152] The above description merely exemplarily explains the technical idea of the present invention. For those with ordinary knowledge in the technical field to which the present invention pertains, various modifications, changes, and substitutions are possible without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention and the accompanying drawings are not for limiting the technical idea of the present invention, but for explanatory purposes. The scope of the technical idea of the present invention is not limited by such embodiments and the accompanying drawings. The scope of protection of the present invention should be construed by the following claims, and all technical ideas within the equivalent scope should be construed as being included in the scope of the rights of the present invention.

Claims

1. A stator, a shaft disposed inside the stator, a magnet coupled to the shaft, and a cover disposed outside the magnet, comprising: the cover includes a first part and a second part extending from one side of the first part, an inner surface of the magnet contacts an outer surface of the shaft, an outer surface of the magnet contacts an inner surface of the first part, a part of an inner surface of the second part contacts an outer surface of the shaft, and the remaining part is disposed spaced apart from the outer surface of the shaft, and a first space (S1) is disposed between the outer surface of the shaft and one end surface of the magnet, the cover includes a third part extending from the other side of the first part, a part of an inner surface of the third part contacts an outer surface of the shaft, and the remaining part is disposed spaced apart from the outer surface of the shaft, and a second space (S2) is disposed between the outer surface of the shaft and the other end surface of the magnet, the first space (S1) is disposed on one side of the magnet in the axial direction, the second space (S2) is disposed on the other side of the magnet in the axial direction, the cover includes a plurality of first regions disposed at intervals in the circumferential direction, the first space and the second space are connected by a space under the first region,

2. The motor according to claim 1, wherein a radial distance from the outer surface of the shaft to the first region is smaller than a shortest radial distance from the outer surface of the shaft to the outer surface of the magnet.

3. The magnet includes a first unit magnet and a second unit magnet, the first region is disposed between the first unit magnet and the second unit magnet, the motor according to claim 1 or 2, wherein the first region is disposed along the axial direction.

4. The motor according to any one of claims 1 to 3, wherein the cover includes a second region having a multi-layer structure in the radial direction centered on the axis.

5. The motor according to claim 4, wherein the cover includes a first layer and a second layer laminated on the first layer in the second region, and an edge on one side of the second layer is disposed to be inclined with respect to an edge on one side of the first layer.

6. The shaft includes a plurality of protrusions that contact the magnet. The motor according to any one of claims 1 to 5, wherein the plurality of protrusions include a first surface protruding from an outer peripheral surface of the shaft and a second surface recessed and disposed on an inner peripheral surface of the shaft.

7. The motor according to any one of claims 1 to 6, wherein the shaft includes a plurality of second holes penetrating inside and outside the shaft, and a plurality of protrusions respectively disposed in the plurality of second holes and at least a part of which protrudes from an outer peripheral surface of the shaft to contact the magnet.

8. The plurality of protrusions are spaced apart along a circumferential direction of the shaft. The motor according to claim 6 or claim 7, wherein a circumferential separation distance between the plurality of protrusions is greater than or equal to a width of the magnet.

9. The plurality of protrusions are spaced apart along an axial direction of the shaft. The motor according to any one of claims 6 to 8, wherein an axial separation distance of the protrusions is less than or equal to a length of the magnet.

10. The motor according to claim 6, wherein the first surface and the second surface each include at least one flat surface.

Images