motor

Abstract

The present invention provides a motor. A motor according to one embodiment of the present disclosure includes a housing into which a stator core is press-fitted. A refrigerant supply groove for distributing and spraying refrigerant is formed in the inner circumferential surface of the housing. This ensures a uniform refrigerant supply without increasing the size of the motor or adding separate components.

Description

Technical Field

[0001] The present disclosure relates to a motor, and more particularly, to a motor having a structure in which a flow path through which a refrigerant flows is formed in an inner wall of a housing. Background Art

[0002] A motor is a device that converts electrical energy into mechanical energy, and is used as a driving source for various home appliances, electric vehicles, hybrid vehicles including an internal combustion engine, and the like.

[0003] As is well known, a motor includes a stator core, a stator coil, a rotor core, and a rotating shaft, and is operated by power applied to the stator coil.

[0004] Energy loss occurs during the conversion of electrical energy into mechanical energy, and the energy loss is mainly in the form of heat energy.

[0005] When the temperature inside the motor excessively increases due to heat generation, permanent magnets included in the rotor may be irreversibly demagnetized, and the efficiency of the motor may be reduced, or the motor may stop due to overheating of the stator coil.

[0006] As one of the causes of heat generation, current flows through the stator coil while generating heat. In particular, excessive heat may be generated at a portion where the stator coil is bent to bend or where the stator coils are coupled to each other.

[0007] Prior art document 1 (China Patent Gazette CN 204906112U) discloses a motor cooled by a refrigerant.

[0008] The motor disclosed in Prior Art Document 1 has a structure in which refrigerant moves in the axial direction through a flow path formed through a stator core.

[0009] Therefore, the motor may have problems in that a magnetic path area is reduced and a size of a stator core is increased in a radial direction.

[0010] Furthermore, since additional components are required for distributing the refrigerant to each of the plurality of flow paths, manufacturing and assembling processes may be complicated and manufacturing costs may increase.

[0011] Prior art literature

[0012] Patent Literature

[0013] Prior art document: China Patent Gazette CN 204906112 U (December 23, 2015) Summary of the Invention

[0014] The present disclosure aims to provide a motor having a structure capable of solving the above-mentioned problems.

[0015] First, an aspect of the present disclosure is to provide a motor having a structure capable of evenly supplying refrigerant to both end portions of a stator core in an axial direction.

[0016] Another aspect of the present disclosure is to provide a motor having a structure capable of evenly supplying refrigerant to both ends of a stator core without increasing the size of the stator core.

[0017] Another aspect of the present disclosure is to provide a motor having a structure capable of distributing refrigerant in a circumferential direction of a stator core without adding additional components.

[0018] Another aspect of the present disclosure is to provide a motor having a structure capable of spraying refrigerant moved to both ends of a stator core toward a shaft.

[0019] To achieve the above aspects, a motor according to one embodiment of the present disclosure includes a housing in which a stator core is coupled to an inner circumferential surface of the housing.

[0020] A main flow path is formed between the stator core and the inner peripheral surface of the housing, the main flow path being a path along which refrigerant moves in a circumferential direction of the stator core.

[0021] Furthermore, a branch flow path, which is a path through which the refrigerant moves in the axial direction of the stator core, is formed between the stator core and the inner peripheral surface of the case.

[0022] Furthermore, the branch flow path communicates with the main flow path.

[0023] Furthermore, main slots are formed in the inner peripheral surface of the housing and extend in the circumferential direction of the stator core.

[0024] Furthermore, branch grooves are recessed in the inner peripheral surface of the housing, and extend in the axial direction of the stator core.

[0025] Furthermore, the main flow path is a space between the main groove and the inner peripheral surface of the housing facing the main groove, and the branch flow path is a space between the branch groove and the inner peripheral surface of the housing facing the branch groove.

[0026] In addition, a motor according to one embodiment of the present disclosure includes: a shell, in which an accommodating space is provided, and the shell is provided with a refrigerant supply hole formed through its outer peripheral surface in a radial direction; a stator core, which is arranged in the accommodating space and connected to the inner peripheral surface of the shell; a stator coil, which is wound around the stator core; a rotor core, which is arranged in a rotatable manner and is spaced a predetermined distance from the inner peripheral surface of the stator core; and a shaft, which is connected through a central portion of the rotor core.

[0027] Furthermore, a refrigerant supply groove is recessed from a portion of the inner circumferential surface of the housing coupled to the stator core.

[0028] Furthermore, the refrigerant supply groove includes a main groove communicating with the refrigerant supply hole and extending in a circumferential direction of the stator core; and branch grooves extending in an axial direction on both sides of the main groove and communicating with the main groove.

[0029] Furthermore, the main groove and the inner peripheral surface of the housing facing the main groove form a main flow path through which the refrigerant introduced through the refrigerant supply hole flows.

[0030] Furthermore, the branch groove and the inner peripheral surface of the housing facing the branch groove form a branch flow path through which the refrigerant from the main flow path branches to both sides in the axial direction of the stator core.

[0031] Furthermore, the main groove and the inner peripheral surface of the housing facing the main groove form a main flow path through which the refrigerant introduced through the refrigerant supply hole flows.

[0032] In addition, the portion of the branch groove that overlaps with the inner circumferential surface of the shell in the radial direction forms a branch flow path together with the inner circumferential surface of the shell, and the refrigerant moving through the branch flow path is discharged into the accommodating space via the portion of the branch groove that is open toward the accommodating space.

[0033] In addition, the branch slots are formed as a plurality of branch slots in the circumferential direction of the stator core, the main slot has a predetermined width in the axial direction, and the portion of the main slot where adjacent branch slots in the circumferential direction are connected is provided with a bottleneck portion having a narrower width.

[0034] In addition, the main groove has a predetermined width in the axial direction, and the branch grooves each have a predetermined length in the axial direction.

[0035] Furthermore, a value obtained by adding a value of the axial width of the main slot and a sum of axial lengths of the branch slots located on both sides of the main slot is larger than a value of the axial length of the stator core.

[0036] Furthermore, the inner peripheral surface of the housing is provided with a refrigerant dispersion surface arranged at an end portion of the branch groove, and the branch groove overlaps with the refrigerant dispersion surface in the axial direction.

[0037] Furthermore, the refrigerant dispersion surface is formed to be inclined in a direction away from the main groove.

[0038] Furthermore, the inner peripheral surface of the housing is provided with a refrigerant dispersion groove formed to be recessed and connected to an end portion of the branch groove.

[0039] Furthermore, each of the refrigerant dispersion grooves is formed in a quarter spherical shape that is open toward the branch groove and the shaft.

[0040] In addition, the housing includes a main housing having both sides open, and covers respectively coupled to each side of the main housing.

[0041] Furthermore, each cover is provided with a protruding coupling portion protruding toward the main housing to engage with an inner peripheral surface of an opening portion of the main housing, and the refrigerant dispersion surface is formed at an end portion of the protruding coupling portion.

[0042] The housing includes a main housing with both sides open, and a cover coupled to each side of the main housing. Each cover is provided with a protruding coupling portion that protrudes toward the main housing to engage with the inner peripheral surface of the open portion of the main housing, and the refrigerant dispersion groove is formed at an end of the protruding coupling portion.

[0043] Furthermore, the outer peripheral surface of the housing is provided with a base portion formed to protrude outward and having a refrigerant storage space therein.

[0044] Furthermore, a portion of the housing facing the base is partially opened toward the refrigerant storage space, the refrigerant storage space and the accommodating space communicate with each other, and the base is provided with a refrigerant discharge hole through which the refrigerant introduced into the refrigerant storage space is discharged.

[0045] Furthermore, the base portion is formed to have an axial length longer than that of the stator core, and a portion of the housing where the base portion is formed is provided with a through hole communicating the refrigerant storage space and the accommodating space.

[0046] Furthermore, the through hole is formed as a plurality of through holes, and the plurality of through holes are arranged on both sides of the main groove.

[0047] In addition, the accommodation space includes a first accommodation space disposed at one side of the stator core and a second accommodation space disposed at the other side opposite to the one side of the stator core.

[0048] Furthermore, the through-hole is formed as a plurality of through-holes. One of the plurality of through-holes connects the first storage space and the refrigerant storage space, and another of the plurality of through-holes connects the second storage space and the refrigerant storage space. Furthermore, a bridge portion forming a portion of the main groove is provided between the one through-hole and the other through-hole.

[0049] In addition, a motor according to one embodiment of the present disclosure includes: a shell, in which an accommodating space is provided, and the shell is provided with a refrigerant supply hole formed through its outer peripheral surface in a radial direction; a stator core, which is arranged in the accommodating space and connected to the inner peripheral surface of the shell; a stator coil, which is wound around the stator core; a rotor core, which is arranged in a rotatable manner and is spaced a predetermined distance from the inner peripheral surface of the stator core; and a shaft, which is connected through a central portion of the rotor core.

[0050] Furthermore, a refrigerant supply flow path is formed between the inner peripheral surface of the housing and the stator core.

[0051] Furthermore, the refrigerant supply flow path includes a main flow path communicating with the refrigerant supply hole and extending in the circumferential direction of the stator core, and branch flow paths extending in the axial direction on both sides of the main flow path and communicating with the main flow path.

[0052] Furthermore, a refrigerant supply groove is recessed from a portion of the inner circumferential surface of the housing that is coupled to the stator core. The refrigerant supply groove includes a main groove that communicates with the refrigerant supply hole and extends in a circumferential direction of the stator core; and branch grooves that extend axially on both sides of the main groove and communicate with the main groove.

[0053] Furthermore, the main flow path is formed by the main groove and the inner peripheral surface of the housing facing the main groove, and the branch flow path is formed by the branch groove and the inner peripheral surface of the housing facing the branch groove.

[0054] According to one embodiment of the present disclosure, the following effects can be achieved.

[0055] First, in a housing, a stator core is coupled to an inner peripheral surface of the housing, and a circumferential flow path is formed between the housing and the stator core, through which refrigerant moves in a circumferential direction of the stator core.

[0056] Furthermore, an axial flow path is formed between the housing and the stator core. The axial flow path communicates with the circumferential flow path, and the refrigerant moves in the axial direction of the stator core via the axial flow path.

[0057] Therefore, the refrigerant can be balancedly supplied to both end portions of the stator core via the circumferential flow path and the axial flow path.

[0058] Thereby, both end portions of the stator core, which are one of the main heat sources of the motor, can be cooled in a balanced manner.

[0059] Therefore, an excessive increase in the internal temperature of the motor can be suppressed.

[0060] Furthermore, a circumferential flow path and an axial flow path are formed in a space between the slots formed on the inner peripheral surface of the housing and the outer peripheral surface of the stator core.

[0061] Therefore, the refrigerant can be evenly supplied to both end portions of the stator core without requiring a separate process for forming a flow path in the stator core or adding a separate component for distributing the refrigerant to the stator core.

[0062] Thereby, the refrigerant can be evenly supplied to both end portions of the stator core without increasing the size of the stator core to form a flow path for supplying the refrigerant or adding a separate component.

[0063] As a result, while the refrigerant is evenly supplied to both ends of the stator core, the motor is miniaturized and the assembly process of the motor is simplified, thereby reducing the manufacturing cost of the motor.

[0064] Furthermore, a refrigerant dispersion structure that sprays refrigerant toward the center of the shaft is formed at each end portion of the axial flow path.

[0065] Therefore, the refrigerant moving through the axial flow path may collide with the refrigerant dispersion structure to be sprayed toward the center of the shaft.

[0066] Therefore, the refrigerant may be sprayed toward the crown portions and end turns of the stator coil at both ends of the stator core.

[0067] Therefore, it is possible to increase the area of the portion of the outer peripheral surface of the crown portion and the end turn that comes into contact with the sprayed refrigerant.

[0068] As a result, heat exchange between the stator coil and the refrigerant can be performed more evenly. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 is a perspective view of a motor according to one embodiment.

[0070] Figure 2 It shows the basis after cutting and decomposition Figure 1 A perspective view of the housing.

[0071] Figure 3 It shows that according to Figure 1 A three-dimensional view of the stator core.

[0072] Figure 4 The basis for the section along line IV-IV is shown. Figure 1 A cross-sectional view of the motor.

[0073] Figure 5 The basis for the section along line VV is shown Figure 1 A cross-sectional view of the motor.

[0074] Figure 6 It shows that according to Figure 2 A partial perspective view of another embodiment of a housing.

[0075] Figure 7 It shows Figure 4 An enlarged partial cross-sectional view of area A.

[0076] Figure 8 It shows that according to Figure 7 A partial cross-sectional view of another embodiment of a motor.

[0077] Figure 9 It shows that according to Figure 7 A partial cross-sectional view of another embodiment of a motor. DETAILED DESCRIPTION

[0078] Hereinafter, a motor according to an embodiment disclosed herein will be described in detail with reference to the accompanying drawings.

[0079] Hereinafter, descriptions of several components will be omitted in order to clarify the technical features of the present disclosure.

[0080] 1. Definition of terms

[0081] The term "energization" used in the following description refers to a component being electrically connected to another component or connected to achieve information communication. Energization can be implemented by means of wires, communication cables, etc.

[0082] The term “front side” used in the following description refers to a direction toward the first cover 18 , and the term “rear side” refers to a direction toward the second cover 19 .

[0083] The term “upper side” used in the following description refers to a direction in which the refrigerant supply part 13 protrudes from the housing 10 .

[0084] The term “lower side” used in the following description refers to a direction in which the base 15 is formed on the housing 10 .

[0085] 2. Description of the motor 1 according to one embodiment of the present disclosure

[0086] Figures 1 to 4 A motor 1 is shown which rotates by receiving electric power from an external power source (not shown).

[0087] A motor 1 according to one embodiment of the present disclosure includes a housing 10 , a stator 20 , and a rotor 30 .

[0088] In addition, although not shown, the motor 1 according to the present embodiment may include an external power source (not shown) and an inverter that converts the external power into three-phase power to drive the motor 1 .

[0089] Next, each configuration of the motor 1 will be described in detail.

[0090] (1) Description of Housing 10

[0091] First, refer to Figure 1 、 Figure 2 and Figure 4 The housing 10 is described. Figure 2 , the housing 10 is shown cut in half.

[0092] The housing 10 defines the appearance of the motor 1. In addition, the housing 10 is provided with a predetermined accommodation space V1 in which the stator 20 and the rotor 30 are accommodated, and a refrigerant storage space V2 formed in the housing in which the refrigerant exchanging heat is stored.

[0093] In the illustrated embodiment, the housing 10 includes a main housing 11 , both sides of which are open, and a first cover 18 and a second cover 19 that cover the two open sides of the main housing 11 and are coupled to the main housing 11 .

[0094] However, the embodiment is not limited thereto, and in one embodiment not shown, the main housing 11 may be implemented in a form in which only one side thereof is open. Here, the main housing 11 may be formed integrally with the first cover 18 or the second cover 19 .

[0095] The main housing 11 includes a main body portion 12 formed in a cylindrical shape and a base portion 15 formed on a lower side of an outer peripheral surface of the main body portion 12 .

[0096] The accommodation space V1 is formed by the inner peripheral surface of the main body portion 12 and the first cover 18 and the second cover 19 covering both sides of the main housing 11 .

[0097] The base portion 15 may be formed in a square column shape having an open front side surface, an open rear side surface, and an open upper side surface. The open upper side of the base portion 15 is coupled to the outer peripheral surface of the body portion 12.

[0098] The refrigerant storage space V2 is formed by the outer peripheral surface of the body portion 12 and the first cover 18 and the second cover 19 covering both sides of the base portion 15 .

[0099] The upper side of the outer peripheral surface of the body portion 12 is provided with a refrigerant supply portion 13 protruding from the housing 10. The refrigerant supply portion 13 is provided with a refrigerant supply hole 13a formed through the housing 10, which communicates the accommodating space V1 with the outside of the housing 10.

[0100] The refrigerant supply part 13 is connected to a refrigerant circulation part (not shown) that supplies refrigerant to the interior of the housing 10 , and the refrigerant is introduced into the housing 10 through a refrigerant supply hole 13 a .

[0101] The through-hole 12a may be formed at a portion of the body portion 12 facing the base portion 15. Therefore, the refrigerant introduced into the body portion 12 to cool the stator 20 and the rotor 30 may be introduced into the refrigerant storage space V2 via the through-hole 12a.

[0102] One side surface of the base 15 is provided with a refrigerant discharge portion 16 protruding therefrom, and the refrigerant discharge portion 16 is provided with a refrigerant discharge hole 16a formed therethrough to communicate the refrigerant storage space V2 with the outside of the base 15. Therefore, the refrigerant introduced into the refrigerant storage space V2 can be discharged through the refrigerant discharge hole 16a.

[0103] In an embodiment not shown, the refrigerant discharge portion 16 may be connected to a refrigerant circulation portion (not shown). The refrigerant cooled during circulation in the refrigerant circulation portion (not shown) is introduced back into the accommodation space V1 via the refrigerant supply portion 13 .

[0104] A stator core 21 to be described later is coupled to the inner peripheral surface of the body portion 12. In one embodiment, the stator core 21 may be press-fitted to the inner peripheral surface of the body portion 12.

[0105] The accommodation space V1 includes a first accommodation space V11 located at the front side of the stator core 21 and a second accommodation space V12 located at the rear side of the stator core 21 .

[0106] A plurality of through holes 12 a for communicating the accommodating space V1 and the refrigerant storage space V2 are provided, and the plurality of through holes 12 a may be formed at positions corresponding to the first accommodating space V11 and at positions corresponding to the second accommodating space V12 .

[0107] A bridge portion 14 is formed between the through hole 12 a formed at a position corresponding to the first accommodation space V11 and the through hole 12 a formed at a position corresponding to the second accommodation space V12 .

[0108] The bridge portion 14 forms a portion of the main slot 124. When the bridge portion 14 is formed, the main slot 124 may surround the stator core 21 in the circumferential direction of the stator core 21 without being cut in the middle.

[0109] Therefore, the refrigerant flowing through the main groove 124 is prevented from being directly introduced into the refrigerant storage space V2 via the through hole 12 a.

[0110] The refrigerant flowing through the main groove 124 is discharged into the first and second accommodation spaces V11 and V12 through the branch grooves 125 and 126 to cool the stator 20 and the rotor 30 , and then introduced into the refrigerant storage space V2 through the through-hole 12 a .

[0111] The refrigerant supply portion 13 is formed at a position overlapping with the stator core 21 in the radial direction, and a refrigerant supply flow path RF is formed between the inner peripheral surface of the main body 12 and the outer peripheral surface of the stator core 21. The refrigerant supply flow path RF is used to supply the refrigerant introduced through the refrigerant supply hole 13a to the first accommodating space V11 and the second accommodating space V12.

[0112] The refrigerant supply flow path RF includes a main flow path MF and branch flow paths BF.

[0113] The main flow path MF extends in the circumferential direction of the stator core 21 and communicates with the refrigerant supply hole 13 a .

[0114] Therefore, the refrigerant introduced into the refrigerant supply hole 13 a moves in the circumferential direction through the main flow path MF between the stator core 21 and the inner peripheral surface of the main body portion 12 .

[0115] The branch flow paths BF extend in the axial direction from both sides of the main flow path MF.

[0116] Specifically, the branch flow paths BF are formed to extend from both sides of the main flow path MF toward the front and rear sides, respectively, and may be formed in plurality in the circumferential direction of the stator core 21. The plurality of branch flow paths BF are arranged to be spaced apart from each other by a predetermined distance in the circumferential direction.

[0117] Furthermore, the branch flow path BF communicates with the main flow path MF.

[0118] Therefore, the refrigerant flowing through the main flow path MF is introduced into the branch flow path BF, moves to the first accommodating space V11 and the second accommodating space V12 via the branch flow path BF, and is then discharged.

[0119] An inner peripheral surface of the body portion 12 facing the outer peripheral surface of the stator core 21 is provided with a refrigerant supply groove 123 having a refrigerant supply flow path RF concavely formed therein.

[0120] A refrigerant supply flow path RF is formed in a space between the refrigerant supply groove 123 and an outer peripheral surface of the stator core 21 facing the refrigerant supply groove 123 .

[0121] The refrigerant supply tank 123 includes a main tank 124 and branch tanks 125 and 126 .

[0122] The main slots 124 extend in the circumferential direction of the stator core 21 and are connected to the refrigerant supply holes 13 a .

[0123] The main flow path MF is formed in a space between the main slots 124 and an outer peripheral surface of the stator core 21 facing the main slots 124 .

[0124] The branch grooves 125 and 126 include a first branch groove 125 and a second branch groove 126 .

[0125] The first branch groove 125 is connected to the front side of the main groove 124 and extends toward the front side in the axial direction. The second branch groove 126 is connected to the rear side of the main groove 124 and extends toward the rear side in the axial direction.

[0126] The branch flow paths BF are formed in spaces between the first and second branch slots 125 and 126 and an outer peripheral surface of the stator core 21 facing the first and second branch slots 125 and 126 .

[0127] The main groove 124 has a predetermined width W1 in the axial direction. In addition, the first branch groove 125 and the second branch groove 126 have a predetermined length D1 in the axial direction.

[0128] A value W1+D1+D1 obtained by adding the value W1 of the axial width of the main slot 124 to the sum D1+D1 of the axial lengths of the first and second branch slots 125 and 126 is greater than the value of the axial length of the stator core 21 .

[0129] Ends of the first branch slots 125 face the first accommodation space V11 instead of the outer peripheral surface of the stator core 21 , and ends of the second branch slots 126 face the second accommodation space V12 instead of the outer peripheral surface of the stator core 21 .

[0130] Therefore, the refrigerant transferred through the branch flow path BF may be transferred from each end portion of the first and second branch grooves 125 and 126 and then discharged to the first and second accommodation spaces V11 and V12 , respectively.

[0131] Both sides of the inner circumferential surface of the body portion 12 are formed with first and second coupling grooves 121 and 122 , and the stator core 21 is press-fitted into the first and second coupling grooves 121 and 122 .

[0132] The first coupling groove 121 is formed to be recessed at the front side of the body portion 12 , and the second coupling groove 122 is formed to be recessed at the rear side of the body portion 12 .

[0133] The first coupling groove 121 is formed at the front side of the main body 12 in the circumferential direction to have a predetermined length in the axial direction. In addition, the second coupling groove 122 is formed at the rear side of the main body 12 in the circumferential direction to have a predetermined length in the axial direction. The predetermined lengths may correspond to the lengths of the first protruding coupling portion 181 of the first cover 18 and the second protruding coupling portion 191 of the second cover 19, which will be described later.

[0134] The radial thickness of a portion of the main body portion 12 where the first coupling groove 121 and the second coupling groove 122 are formed is thinner than that of other portions.

[0135] The first cover 18 and the second cover 19 are formed to cover both open sides of the main housing 11. The first cover 18 and the second cover 19 are formed in a shape in which a square is coupled to a lower side of a circle.

[0136] However, the shape is not limited thereto, and in an embodiment not shown, the first cover 18 and the second cover 19 may be formed in various shapes having a size capable of covering both open sides of the main housing 11 .

[0137] The first protruding coupling portion 181 is formed to protrude from the rear side surface of the first cover 18 by a predetermined length, which is equal to the axial length of the first coupling groove 121 .

[0138] The first protruding coupling portion 181 is formed in a shape that engages with the first coupling groove 121 of the main body portion 12. Therefore, when the first protruding coupling portion 181 is inserted into the open front side of the main body portion 12, the outer peripheral surface of the first protruding coupling portion 181 and the first coupling groove 121 engage with each other. Therefore, the first cover 18 and the front side of the main housing 11 can be coupled to each other.

[0139] The second protruding coupling portion 191 is formed to protrude by a predetermined length from the front side surface of the second cover 19. The predetermined length is equal to the axial length of the second coupling groove 122.

[0140] The second protruding coupling portion 191 is formed in a shape that engages with the second coupling groove 122 of the main body portion 12. Therefore, when the second protruding coupling portion 191 is inserted into the open rear side of the main body portion 12, the outer peripheral surface of the second protruding coupling portion 191 and the second coupling groove 122 engage with each other. Therefore, the second cover 19 and the rear side of the main housing 11 can be coupled to each other.

[0141] Although not shown, the first cover 18 and the front end of the main housing 11 may have a sealing portion (not shown) at the portion where the first cover 18 and the front end of the main housing 11 contact each other. Furthermore, the second cover 19 and the rear end of the main housing 11 may have a sealing portion (not shown) at the portion where the second cover 19 and the rear end of the main housing 11 contact each other. Thus, leakage of refrigerant through the portion where the first cover 18 and the main housing 11 are coupled together, and the portion where the second cover 19 and the main housing 11 are coupled together, can be suppressed.

[0142] A first bearing portion 182 and a first bearing hole 182 a are formed in the first cover 18 , and a second bearing portion 192 and a second bearing hole 192 a are formed in the second cover 19 .

[0143] The front side of the shaft 32 to be described later is accommodated in the first bearing hole 182 a , and the rear side of the shaft 32 is accommodated in the second bearing hole 192 a .

[0144] As described above, the stator core 21 is coupled to the inner peripheral surface of the main body portion 12 , and the stator coil 22 is wound around the stator core 21 .

[0145] The stator core 21 and the stator coil 22 constitute the stator 20 .

[0146] Below, we will refer to Figure 3 and Figure 4 The stator 20 and the rotor 30 are described.

[0147] (2) Description of stator 20

[0148] A magnetic field that rotates a rotor 30 to be described later is formed in the stator 20 .

[0149] The stator 20 includes a stator core 21 and a stator coil 22 wound around the stator core 21 .

[0150] The stator core 21 includes a yoke portion 211 formed in an annular shape and a plurality of teeth 212 protruding radially from an inner peripheral surface of the yoke portion 211 .

[0151] The stator core 21 is formed to extend a predetermined length in the axial direction.

[0152] In addition, the stator core 21 can be formed by stacking a plurality of electric sheets having a predetermined thickness in an axial direction in an insulating manner. Therefore, it is possible to suppress the occurrence of iron loss when the motor 1 operates.

[0153] The teeth 212 are arranged to be spaced apart from each other in the circumferential direction within the yoke 211 , and a slit 213 as a prescribed space is formed between the teeth 212 adjacent to each other in the circumferential direction.

[0154] That is, the slit 213 is formed in plural, and the plurality of teeth 212 and the plurality of slits 213 are alternately arranged in the circumferential direction.

[0155] The stator coil 22 may be wound around the plurality of teeth 212 and the plurality of slots 213 in a predetermined pattern.

[0156] The stator coil 22 includes a conductor and an insulating coating surrounding the conductor. As the stator coil 22, a rectangular copper wire (refer to FIG. Figure 5 ) is bent into a conductor segment or hairpin magnetic wire (hereinafter referred to as "hairpin") formed by approximating a "U" shape.

[0157] The stator coil 22 is electrically connected by inserting the stator coil 22 into the plurality of slits 213 in a predetermined pattern in one direction and then welding the ends of the stator coil 22 protruding toward one side of the stator core 21 in a predetermined pattern.

[0158] Therefore, one side of the stator core 21 is formed with an end turn portion where a bent portion of the stator coil 22 is located, and the other side of the stator core 21 is formed with a crown portion electrically coupling the ends of the stator coil 22 .

[0159] When the motor 1 is operated, heat generated at the end turns and the crown is relatively greater than that at other parts. Therefore, it is preferable to spray the refrigerant evenly to both sides of the stator core 21 where the end turns and the crown are formed.

[0160] In one embodiment, a stranded wire may be used as the stator coil 22. Here, the stator coil 22 passes through the plurality of slits 213 in the axial direction and is wound around the plurality of teeth 212 in a predetermined pattern.

[0161] In an embodiment not shown, the stator coil 22 is electrically connected to an inverter (not shown) that converts power applied from an external power source into AC power for operating the motor 1 and then supplies the AC power to the stator coil 22 .

[0162] When current is applied from an inverter (not shown) to the stator coil 22, a magnetic field is formed around the stator coil 22. That is, a rotating magnetic field is formed in the stator 20 that rotates the rotor 30.

[0163] A rotor receiving hole 21 a is formed through the radially inner sides of the plurality of teeth 212 , and the rotor 30 is rotatably disposed in the rotor receiving hole 21 a .

[0164] The rotor 30 rotates by interaction with the rotating magnetic field of the stator 20 .

[0165] (3) Description of the rotor 30

[0166] The rotor 30 includes a rotor core 31 and a shaft 32 .

[0167] The rotor core 31 is formed to extend a predetermined length in the axial direction.

[0168] The rotor core 31 may be formed in the shape of an annular column, and a shaft receiving hole 31 a passing therethrough is formed in a central portion of the rotor core 31 .

[0169] In addition, the rotor core 31 can be formed by stacking a plurality of electric sheets having a predetermined thickness in an axial direction in an insulated manner. Therefore, it is possible to suppress the occurrence of iron loss when the motor 1 operates.

[0170] In an embodiment not shown, the rotor core 31 may include a permanent magnet (not shown). In this case, the rotating magnetic field of the stator 20 and the magnetic field of the permanent magnet (not shown) interact with each other. Therefore, the rotor 30 can rotate relative to the stator 20.

[0171] The shaft 32 is inserted into the shaft receiving hole 31a. In one embodiment, the shaft receiving hole 31a and the shaft 32 may be coupled to each other in a press-fit manner.

[0172] The shaft 32 protrudes to both sides of the rotor core 31 in the axial direction, the front side of the shaft 32 is received in the first bearing hole 182 a , and the rear side of the shaft 32 is received in the second bearing hole 192 a .

[0173] That is, electric energy is supplied to the stator 20 , and by interaction of a magnetic field formed in the stator 20 and a magnetic field formed in the rotor 30 , the electric energy is converted into mechanical rotational energy.

[0174] In the following, reference will be made to Figure 4 and Figure 5 The refrigerant circulation process through the main flow path MF and the branch flow paths BF will be described.

[0175] (4) Description of the refrigerant cycle

[0176] The refrigerant introduced through the refrigerant supply hole 13 a is introduced into the main flow path MF, moves through the main flow path MF to be introduced into the branch flow path BF, and then is discharged into the first and second accommodation spaces V11 and V12 .

[0177] The refrigerant is discharged into the first accommodation space V11 through the branch flow path BF formed in the axial direction in front of the main flow path MF, and is discharged into the second accommodation space V12 through the branch flow path BF formed in the axial direction in rear of the main flow path MF.

[0178] refer to Figure 4 In a state where the stator core 21 is press-fitted, branch flow paths BF are formed between the outer peripheral surface of the stator core 21 and the first branch slots 125 and between the outer peripheral surface and the second branch slots 126 .

[0179] The refrigerant discharged to the first accommodation space V11 through the branch flow path BF is sprayed on the front sides of the stator 20 and the rotor core 31 .

[0180] The refrigerant sprayed on the front sides of the stator 20 and the rotor core 31 exchanges heat with the stator 20 and the rotor core 31. Heat energy is transferred from the stator 20 and the rotor core 31, which have relatively high temperatures, to the refrigerant, which has a lower temperature.

[0181] In addition, the refrigerant discharged to the second accommodation space V12 through the branch flow path BF is sprayed on the rear sides of the stator 20 and the rotor core 31 .

[0182] The refrigerant sprayed on the rear sides of the stator 20 and the rotor core 31 exchanges heat with the stator 20 and the rotor core 31. Heat energy is transferred from the stator 20 and the rotor core 31 having relatively high temperatures to the refrigerant having a lower temperature.

[0183] Therefore, it is possible to cool the stator 20 and the rotor core 31 , which are heated when the motor 1 operates.

[0184] Portions of the stator coil 22 , which are bent or electrically coupled, may be formed to protrude at the front and rear ends of the stator 20 .

[0185] In one embodiment, when a rectangular copper wire is used as the stator coil 22, end turns where the stator coil 22 is bent may be formed at the front and rear ends of the stator 20, and a crown portion for electrically connecting the stator coil 22 may be formed at the rear end of the stator core 21.

[0186] In one embodiment, when a stranded wire is used as the stator coil 22 , portions of the stator coil 22 that are bent and wound around the teeth 212 may be formed at the front and rear ends of the stator 20 .

[0187] When the motor 1 is in operation, the bent or electrically connected portion of the stator coil 22 may generate relatively more heat energy than other portions. That is, the bent or electrically connected portion of the stator coil 22 is one of the main heat sources of the motor 1 .

[0188] The refrigerant discharged into the first accommodation space V11 may be sprayed onto the stator coil 22 protruding from the front end of the stator core 21 . In addition, the refrigerant discharged into the second accommodation space V12 may be sprayed onto the stator coil 22 protruding from the rear end of the stator core 21 .

[0189] Therefore, the portion where the stator coil 22 is bent or electrically coupled, which is one of the main heat sources of the motor 1 , can be cooled.

[0190] refer to Figure 5 , the refrigerant flowing through the main flow path MF is distributed to the branch flow paths BF.

[0191] In a state where the stator core 21 is press-fitted, a main flow path MF is formed between the outer peripheral surface of the stator core 21 and the main slots 124 .

[0192] The main flow path MF surrounds the stator core 21 in the circumferential direction of the stator core 21 .

[0193] The plurality of branch flow paths BF are arranged to be spaced apart from each other in the circumferential direction of the stator core 21 , and each branch flow path BF is electrically connected to the main flow path MF.

[0194] Therefore, the refrigerant flowing through the main flow path MF can flow into each branch flow path BF.

[0195] Since the plurality of branch flow paths BF are arranged to be spaced apart from each other in the circumferential direction, it is possible to suppress excessive refrigerant supply to specific portions of the stator 20 and the rotor core 31 , thereby suppressing an insufficient amount of refrigerant sprayed to another specific portion.

[0196] That is, each end portion of the stator 20 and the rotor core 31 can be uniformly cooled in the circumferential direction.

[0197] The refrigerant discharged to the first and second accommodating spaces V11 and V12 through the branch flow path BF cools the stator 20 and the rotor 30 and is then introduced into the refrigerant storage space V2 through the through-hole 12 a .

[0198] The refrigerant introduced into the refrigerant storage space V2 is discharged to the outside of the motor 1 through the refrigerant discharge hole 16a and then cooled again while flowing through a refrigerant circulation portion (not shown) to be introduced into the main flow path MF through the refrigerant supply hole 13a.

[0199] 3. Description of the Effects of the Structure Having the Refrigerant Supply Groove 123 Formed on the Inner Surface of the Shell 10

[0200] A main groove 124 forming the main flow path MF and branch grooves 125 and 126 forming the branch flow paths BF are recessed in the inner peripheral surface of the housing.

[0201] Therefore, the refrigerant can be evenly supplied to both ends of the stator core 21 without separately processing the stator core 21 to form a flow path in the stator core 21 or adding a separate component for distributing the refrigerant to the stator core 21 .

[0202] When the flow path is formed in the stator core 21 , the magnetic path area is reduced, which may adversely affect the output of the motor 1 and increase the size of the stator core 21 .

[0203] In addition, when a separate component for distributing refrigerant is added to the stator core 21, the cost for producing the separate component may increase, and the assembly process of the motor 1 may be complicated. That is, the cost for producing the motor 1 may increase.

[0204] Since the refrigerant supply groove 123 is formed on the inner circumferential surface of the housing 10 , the refrigerant can be evenly supplied to both ends of the stator core 21 without reducing the magnetic path area of the stator core 21 , increasing the size, or increasing the manufacturing cost.

[0205] In other words, while the refrigerant is evenly supplied to both ends of the stator core 21 , the motor 1 is miniaturized and the assembly process of the motor 1 is simplified, so that the manufacturing cost of the motor can be reduced.

[0206] 4. Description of the Modified Implementation Methods of the Main Path MF

[0207] In the following, reference will be made to Figure 6 A modified embodiment of the main flow path MF will be described.

[0208] A portion where the branch grooves 125 and 126 adjacent to each other in the main groove 124 are connected in the circumferential direction is provided with a bottleneck portion 124 a having a narrow width.

[0209] The bottleneck portion 124 a may be defined as a space between bottleneck protrusions 1241 protruding from two side surfaces of the main groove 124 facing each other.

[0210] The axial width W2 between the bottleneck protrusions 1241 is formed to be narrower than the axial width W1 of the main groove 124 .

[0211] In the illustrated embodiment, the bottleneck protrusion 1241 protrudes in a square column shape.

[0212] However, the shape is not limited thereto, and in an embodiment not shown, the bottleneck protrusion 1241 may be formed in various shapes. For example, the bottleneck protrusion 1241 may be formed to protrude toward each other from two side surfaces of the main groove 124 facing each other.

[0213] Since the cross-sectional area of the flow path is immediately reduced while the refrigerant flowing through the main flow path MF flows into the bottleneck portion 124 a , the pressure of the refrigerant may be instantaneously increased.

[0214] Since the pressure difference between the main flow path MF and the branch flow path BF increases immediately, the refrigerant can be introduced from the main flow path MF into the branch flow path BF more evenly.

[0215] That is, without increasing the pressure of the refrigerant introduced through the refrigerant supply hole 13a, the flow rate of the refrigerant discharged through the branch flow path BF can be increased by a simple structural change.

[0216] As a result, the refrigerant may be discharged into the first accommodating space V11 and the second accommodating space V12 more evenly.

[0217] 5. Description of the structure for spraying refrigerant toward the shaft 32

[0218] Next, refer to Figures 7 to 9 , a structure in which the refrigerant having passed through the branch flow path BF is sprayed to the center of the shaft 32 will be described.

[0219] refer to Figure 7 A refrigerant dispersion surface 181 a is formed on the inner circumferential surface of the shell 10 , and the refrigerant dispersion surface 181 a is arranged at the ends of the branch grooves 125 and 126 .

[0220] The refrigerant dispersion surface 181a is formed in plural and is arranged at each end of the plurality of branch grooves 125 and 126. That is, the plurality of refrigerant dispersion surfaces 181a are arranged to be spaced apart from each other in the circumferential direction of the stator core 21.

[0221] The refrigerant moving through the branch flow path BF collides with each of the refrigerant dispersion surfaces 181 a and is then sprayed toward the stator coils 22 protruding from both end portions of the stator core 21 .

[0222] The refrigerant dispersion surface 181a is formed to be inclined in a direction crossing the axial direction. In one embodiment, the refrigerant dispersion surface 181a may be formed perpendicular to the axial direction.

[0223] As a result, the refrigerant colliding with the refrigerant dispersion surface 181 a may be sprayed toward the shaft 32 .

[0224] Because the refrigerant discharged from the branch flow path BF located on the lower side of the motor 1 (based on the installation direction of the motor 1) is affected by gravity, the amount of refrigerant reaching the stator coil 22 located on the upper side of the motor 1 is reduced. As a result, the efficiency of cooling the stator coil 22 located on the lower side of the motor 1 may be reduced.

[0225] However, since the refrigerant dispersion surface 181a is formed to be inclined in a direction intersecting the axial direction, the refrigerant colliding with the refrigerant dispersion surface 181a can be sprayed upward toward the center of the shaft 32. Therefore, the refrigerant can be sufficiently sprayed onto the stator coil 22 located on the lower side.

[0226] As a result, the stator coils 22 located on the upper and lower sides can be uniformly cooled.

[0227] In the illustrated embodiment, the refrigerant dispersion surface 181 a is formed at an end of the first protruding coupling portion 181 and an end of the second protruding coupling portion 191 .

[0228] When the first cover 18 is inserted into the opened front side of the main housing 11 , the rear end surface of the first protruding coupling portion 181 is arranged to face the end of the first branch groove 125 .

[0229] As a result, the refrigerant moving through the first branch groove 125 collides with the rear end surface of the first protruding coupling portion 181. That is, the refrigerant collides with the refrigerant dispersion surface 181a formed at the end of the first protruding coupling portion 181 to be sprayed toward the center of the shaft 32.

[0230] When the second cover 19 is inserted into the opened rear side of the main housing 11 , the front end surface of the second protruding coupling portion 191 is arranged to face the end of the second branch groove 126 .

[0231] As a result, the refrigerant moving through the second branch groove 126 collides with the front end surface of the second protruding coupling portion 191. That is, the refrigerant collides with a refrigerant dispersion surface (not shown) formed at the end of the second protruding coupling portion 191 to be sprayed toward the center of the shaft 32.

[0232] To improve the refrigerant dispersion effect, the first and second protruding coupling parts 181 and 191 may be formed to protrude radially inward from the portion of the housing 10 where the refrigerant supply groove 123 is formed. That is, in the coupled state, there is a step difference between the first and second protruding coupling parts 181 and 191 and the main housing 11.

[0233] refer to Figure 8 , which shows a modified embodiment of the refrigerant dispersion surface 181 a. The refrigerant dispersion surface 1810 a according to the modified embodiment may be formed to be inclined in a direction away from the main groove 124.

[0234] The inclined refrigerant dispersion surface 1810 a may be formed by chamfering a corner of an inner circumference of an end portion forming the first protruding coupling portion 181 in a circumferential direction.

[0235] Furthermore, a refrigerant dispersion surface (not shown) may be formed by chamfering a corner of an inner circumference of an end portion forming the second protruding coupling portion 191 in a circumferential direction.

[0236] Therefore, the inclined refrigerant dispersion surface 1810 a may be disposed at the end portions of the first and second protruding coupling portions 181 and 191 facing each end portion of the branch grooves 125 and 126 .

[0237] The refrigerant moving through the branch grooves 125 and 126 moves through the inclined refrigerant dispersion surface 1810 a to be sprayed toward the center of the shaft 32 .

[0238] Thereby, the refrigerant can be sprayed farther from each end portion of the stator core 21 .

[0239] Specifically, the refrigerant may be sprayed farther from the front end portion of the stator core 21 , and the refrigerant may be sprayed farther from the rear end portion of the stator core 21 .

[0240] The length of the stator coil 22 protruding from each end portion of the stator core 21 may be changed according to the type or winding method of the stator coil 22 .

[0241] In the case where the protruding length of the stator coil 22 is relatively long, when the slope of the refrigerant dispersion surface 181 a is formed more smoothly, the refrigerant can reach a farther position in the axial direction. Therefore, the refrigerant can be sprayed onto the entire stator coil 22.

[0242] When the protruding length of the stator coil 22 is relatively short, it is preferable to form the slope of the refrigerant dispersion surface 181 a to be steeper or vertical.

[0243] refer to Figure 9 , shows another modified embodiment of the refrigerant dispersion surface 181a. According to another modified embodiment, the end portion of the first protruding coupling portion 181 may be provided with refrigerant dispersion grooves 1810b each formed in a concave shape.

[0244] The refrigerant dispersion groove 1810 b is formed at a position corresponding to each end portion of the first branch groove 125 .

[0245] The refrigerant dispersion grooves 1810 b may be formed in a quarter spherical shape, and each of the refrigerant dispersion grooves 1810 b is opened toward the first branch groove 125 and the shaft 32 .

[0246] Therefore, the refrigerant moving through the first branch groove 125 may move through the curved surface of the refrigerant dispersion groove 1810 b to be concentratedly sprayed toward the center of the shaft 32 .

[0247] That is, the refrigerant can be concentratedly sprayed to a specific portion rather than being sprayed over a larger area.

[0248] When the stator coils 22 protruding toward the front side of the stator core 21 are densely arranged in a specific portion, the cooling effect can be improved by concentratedly spraying the refrigerant to the specific portion.

[0249] Furthermore, the end portions of the second protruding coupling portion 191 according to another modified embodiment may be provided with refrigerant dispersion grooves (not shown) each formed to be concave.

[0250] A refrigerant dispersion groove (not shown) is formed at a position corresponding to each end portion of the second branch groove 126 .

[0251] The refrigerant dispersion grooves (not shown) may be formed in a quarter spherical shape, each of which is open toward the second branch groove 126 and the shaft 32 .

[0252] Therefore, the refrigerant moving through the second branch groove 126 may move through the curved surface of the refrigerant dispersion groove (not shown) to be concentratedly sprayed toward the center of the shaft 32 .

[0253] That is, the refrigerant can be densely sprayed to a specific portion instead of being sprayed over a larger area.

[0254] When the stator coils 22 protruding toward the rear side of the stator core 21 are densely arranged in a specific portion, the cooling effect can be improved by concentratedly spraying the refrigerant to the specific portion.

[0255] The above description has been given of three embodiments as a structure for spraying refrigerant toward the center of the shaft 32. In one embodiment, the above-described refrigerant dispersion surfaces 181a and 1810a and the refrigerant dispersion groove 1810b may be used in combination.

[0256] For example, the refrigerant dispersion surfaces 181a and 1810a may be formed on the upper side and the refrigerant dispersion groove 1810b may be formed on the lower side based on the installation direction of the motor 1. By forming the refrigerant dispersion groove 1810b on the lower side, the distance of the refrigerant sprayed upward from the lower side can be increased.

[0257] Therefore, the refrigerant can be sprayed to a wider range on the upper side, and the refrigerant can smoothly reach the stator coil 22 on the lower side.

[0258] To summarize the above effects, the refrigerant moving through the axial flow path may collide with the refrigerant dispersion structure to be sprayed toward the center of the shaft 32 .

[0259] Therefore, the refrigerant may be sprayed toward the crown portions and end turns of the stator coil 22 located at both ends of the stator core 21 .

[0260] Therefore, it is possible to increase the area of the portion of the outer peripheral surface of the crown portion and the end turn that comes into contact with the sprayed refrigerant.

[0261] As a result, heat exchange between the stator coil 22 and the refrigerant can be performed more evenly.

[0262] While the foregoing description has been given with reference to preferred embodiments, it will be appreciated that those skilled in the art will be able to make various modifications and changes to the present disclosure without departing from the scope of the disclosure as described in the appended claims.

Claims

1. A motor, comprising: a housing having an accommodation space provided therein and provided with a refrigerant supply hole formed through an outer peripheral surface thereof in a radial direction; a stator core arranged in the accommodation space and coupled to an inner peripheral surface of the housing; a stator coil wound around the stator core; a rotor core rotatably arranged and spaced apart from an inner peripheral surface of the stator core by a predetermined distance; as well as a shaft passing through a central portion of the rotor core and coupled thereto, wherein the refrigerant supply groove is recessed from a portion of the inner peripheral surface of the housing coupled to the stator core, and Wherein, the refrigerant supply tank comprises: a main groove communicating with the refrigerant supply hole and extending in a circumferential direction of the stator core; and branch grooves extending in the axial direction on both sides of the main groove and communicating with the main groove, and The branch slots are formed as a plurality of branch slots in the circumferential direction of the stator core. wherein the main groove has a predetermined width in the axial direction, and Wherein, a portion of the main groove where the mutually adjacent branch grooves are connected in the circumferential direction is provided with a bottleneck portion with a narrow width.

2. The motor according to claim 1, wherein The main groove and the inner peripheral surface of the housing facing the main groove form a main flow path through which the refrigerant introduced through the refrigerant supply hole flows, and The branch groove and the inner peripheral surface of the housing facing the branch groove form a branch flow path through which the refrigerant from the main flow path branches to both sides in the axial direction of the stator core.

3. The motor according to claim 1, wherein The main groove and the inner peripheral surface of the housing facing the main groove form a main flow path through which the refrigerant introduced through the refrigerant supply hole flows. wherein a portion of the branch groove that overlaps with the inner peripheral surface of the housing in the radial direction forms a branch flow path together with the inner peripheral surface of the housing, and The refrigerant moving through the branch flow path is discharged into the accommodation space through a portion of the branch groove that is open toward the accommodation space.

4. The motor according to claim 1, wherein The main groove has a predetermined width in the axial direction, Wherein, the branch grooves each have a predetermined length in the axial direction, and A value obtained by adding an axial width of the main slot and a sum of axial lengths of the branch slots located on both sides of the main slot is greater than an axial length of the stator core.

5. The motor according to claim 1, wherein The inner peripheral surface of the shell is provided with a refrigerant dispersion surface arranged at an end portion of the branch groove, and The branch groove overlaps with the refrigerant dispersion surface in the axial direction.

6. The motor according to claim 5, wherein The refrigerant dispersion surface is formed to be inclined in a direction away from the main groove.

7. The motor according to claim 1, wherein The outer peripheral surface of the housing is provided with a base portion formed to protrude outward and having a refrigerant storage space therein, wherein the axial length of the base portion is formed to be longer than that of the stator core, and The portion of the shell where the base is formed is provided with a through hole, and the through hole communicates with the refrigerant storage space and the accommodating space.

8. The motor according to claim 7, wherein The accommodating space includes: a first accommodation space disposed on one side of the stator core; and a second accommodation space disposed on the other side opposite to the one side of the stator core, wherein the through hole is formed into a plurality of through holes, wherein one through-hole among the plurality of through-holes communicates with the first accommodation space and the refrigerant storage space, and another through-hole among the plurality of through-holes communicates with the second accommodation space and the refrigerant storage space, and Wherein, a bridge portion forming a portion of the main groove is provided between the one through-hole among the plurality of through-holes and the other through-hole among the plurality of through-holes.

9. A motor, comprising: a housing having an accommodation space provided therein and provided with a refrigerant supply hole formed through an outer peripheral surface thereof in a radial direction; a stator core arranged in the accommodation space and coupled to an inner peripheral surface of the housing; a stator coil wound around the stator core; a rotor core rotatably arranged and spaced apart from an inner peripheral surface of the stator core by a predetermined distance; as well as a shaft passing through a central portion of the rotor core and coupled thereto, wherein the refrigerant supply groove is recessed from a portion of the inner peripheral surface of the housing coupled to the stator core, and Wherein, the refrigerant supply tank comprises: a main groove communicating with the refrigerant supply hole and extending in a circumferential direction of the stator core; and branch grooves extending in the axial direction on both sides of the main groove and communicating with the main groove, and wherein the inner peripheral surface of the shell is provided with a refrigerant dispersion groove formed to be recessed and connected to the end of the branch groove, and Each of the refrigerant dispersion grooves is formed in a quarter spherical shape that is open toward the branch groove and the shaft.

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