Cooling structure

Abstract

The invention provides a cooling structure. The flow rate and flow velocity of the refrigerant are made uniform at each position in the axial direction of the motor. A motor cooling structure extending in the axial direction is provided with: a refrigerant flow path through which a refrigerant flows in the circumferential direction of a motor; and a supply port that supplies a refrigerant to the refrigerant flow path, the refrigerant flow path having: an expansion part that expands in the axial direction from the supply port and extends in the circumferential direction; and a branch portion extending in the circumferential direction from the expansion portion and branching into a plurality of branch flow paths, the expansion portion having a first protruding portion, extending in the axial direction higher than the first protruding portion, and narrowing the width of the refrigerant flow path in the radial direction of the motor.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a cooling structure of a motor. Background Art

[0002] Patent Document 1 discloses a cylindrical support member that supports the outer circumference of a motor's stator core and forms a flow path for a cooling fluid. According to Patent Document 1, the support member includes an inner wall portion forming a cylindrical shape, an outer wall portion forming a cylindrical shape radially opposite the inner wall portion, and one or more partition walls extending radially between the inner and outer wall portions to partition the flow path formed therebetween.

[0003] Patent Document 1: International Publication No. 2021 / 020468 Summary of the Invention

[0004] The inventors of the present application have studied the following cooling structure. The cooling structure comprises: a refrigerant flow path for allowing refrigerant to flow in the circumferential direction of the motor; and a supply port for supplying refrigerant to the refrigerant flow path. The refrigerant flow path comprises: an expansion portion that expands axially from the supply port and extends circumferentially; and a branch portion that extends circumferentially from the expansion portion and branches into a plurality of branch flow paths. In such a cooling structure, it is effective to equalize the flow rate and / or flow velocity of the refrigerant in the branch portion in the axial direction of the motor. In view of this situation, the present specification provides a technology that is conducive to equalizing the flow rate and / or flow velocity of the refrigerant.

[0005] This specification discloses a cooling structure for a motor extending in an axial direction. The cooling structure comprises: a refrigerant flow path for allowing refrigerant to flow in the circumferential direction of the motor; and a supply port for supplying the refrigerant to the refrigerant flow path. The refrigerant flow path comprises: an expansion portion that expands from the supply port in the axial direction and extends in the circumferential direction; and a branch portion that extends from the expansion portion in the circumferential direction and branches into a plurality of branch flow paths. The expansion portion comprises a first protrusion that extends in the axial direction and narrows the width of the refrigerant flow path in the radial direction of the motor.

[0006] According to the above structure, a portion of the refrigerant supplied from the supply port to the expansion portion is blocked by the first protrusion and temporarily retained within the expansion portion. Due to this temporary retention, the flow resistance acting on the refrigerant in the axial direction within the expansion portion is uniformized, so that the flow rate and / or flow velocity of the refrigerant flowing downstream of the first protrusion, that is, the flow rate and / or flow velocity of the refrigerant flowing in the branch portion, is uniformized in the axial direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 This is a diagram that simply shows the structure of a motor according to one embodiment from a viewpoint toward the axial direction.

[0008] Figure 2 is based on Figure 1 Cross-sectional view of line II-II.

[0009] Figure 3 It is a perspective view showing the shape of the refrigerant flow path.

[0010] Figure 4 It is a perspective view showing the shape of the expansion portion from a radially inner side viewpoint.

[0011] Figure 5 It is a cross-sectional view of the expansion portion in a section perpendicular to the axial direction.

[0012] Figure 6 is the cross section perpendicular to the axis Figure 5 Cross-sectional views of different expansion sections.

[0013] Figure 7 The view from the radial inside shows the Figure 4 A perspective view of different expansion shapes.

[0014] Figure 8 It is a perspective view showing a part of the branch portion.

[0015] Figure 9 This is a diagram showing the shape of a branch portion according to one modification example, viewed from a radial direction.

[0016] Figure 10 This is a diagram briefly showing the structure of a motor housing according to one modification.

[0017] Description of reference numerals:

[0018] 10…motor; 11…stator core; 12…coil; 13…rotor; 14…shaft; 18…cylindrical member; 20…motor housing; 21…supply port; 22…discharge port; 23…inner wall portion; 24…outer wall portion; 25, 26…end wall portions; 30…refrigerant flow path; 31…expansion portion; 32…reduction portion; 33…branch portion; 34…partition wall; 35…protrusion; 35a…first protrusion; 35b…second protrusion; 36…first range; 37…second range; 38…third range; 39…columnar portion; 42…middle wall portion; 43…throttling portion; 330…branch flow path. DETAILED DESCRIPTION

[0019] An embodiment of the present technology will be described with reference to the accompanying drawings. Each figure is for illustration only, and the present embodiment is not limited to the contents of the figures. Furthermore, since each figure is for illustration only, the shapes shown may not be accurate, may not be aligned with each other, or may be partially omitted.

[0020] Figure 1 The structure including the motor 10 is simply shown from a viewpoint facing the axial direction of the motor 10 . Figure 2 So line II-II Figure 1 The structure shown is cut off in a cross-sectional view. Figure 1 As shown, motor 10 includes a stator core 11, coils 12, a rotor 13, and a shaft 14. Stator core 11 is generally cylindrical, with coils 12 wound around it. The specific shape of stator core 11 is not limited herein. Rotor 13 is disposed within the space enclosed by stator core 11. Rotor 13 is mounted on shaft 14 located at the center of motor 10, i.e., motor axis Z. Shaft 14 transmits the rotational motion of rotor 13 to the outside.

[0021] The motor housing 20 has a cylindrical shape extending in the axial direction. The outer peripheral surface of the stator core 11 contacts the inner peripheral surface of the motor housing 20, and the stator core 11 is fixed relative to the inner peripheral surface of the motor housing 20. In other words, the motor housing 20 supports the stator core 11 from the outer side in the radial direction (hereinafter referred to as the radial direction) of the motor 10 with the motor axis Z as a reference. The motor housing 20 can also be understood as a part of the structure of the motor 10. In this case, the motor housing 20 is equivalent to an example of the cylindrical member 18 in the present technology.

[0022] like Figure 2 As shown, the motor housing 20 has an inner wall portion 23 located radially inward and an outer wall portion 24 located radially outward of the inner wall portion 23 and opposing the inner wall portion 23. The stator core 11 is fixed to the inner wall portion 23 of the motor housing 20. A refrigerant flow path 30 is formed within the motor housing 20, that is, between the inner wall portion 23 and the outer wall portion 24. The refrigerant flow path 30 extends in the motor axis Z direction (hereinafter referred to as the axial direction) and allows refrigerant to flow in the circumferential direction (hereinafter referred to as the circumferential direction R) of the motor 10. The inner circumferential surface of the refrigerant flow path 30 is defined by the inner wall portion 23, while the outer circumferential surface of the refrigerant flow path 30 is defined by the outer wall portion 24.

[0023] The inner wall portion 23 and the outer wall portion 24 are connected on one side and the other side in the axial direction respectively by the end wall portions 25 and 26 extending in the radial direction. Therefore, the refrigerant flow path 30 is divided by the inner wall portion 23, the outer wall portion 24 and the end wall portions 25 and 26. In the present embodiment, the above-mentioned structure of the motor housing 20 that divides the refrigerant flow path 30 is equivalent to the cooling structure of the motor 10. In simple terms, the motor housing 20 can also be understood as a cooling structure. The so-called refrigerant refers to a fluid with a cooling effect, and here, it is assumed to be cooling water. However, the refrigerant may also be, for example, oil for cooling.

[0024] The motor housing 20 includes a supply port 21 for receiving refrigerant and a discharge port 22 for discharging refrigerant. The supply port 21 and the discharge port 22 are each connected to a refrigerant flow path 30. The supply port 21 supplies refrigerant to the refrigerant flow path 30 from the outside. The discharge port 22 discharges the refrigerant supplied from the supply port 21 and flowing through the refrigerant flow path 30 to the outside. The refrigerant is pressurized by a pump (not shown) and circulates through the refrigerant flow path 30 and a flow path outside the motor housing 20 (not shown).

[0025] The refrigerant flow path 30 includes an expansion portion 31 connected to the supply port 21, a reduction portion 32 connected to the discharge port 22, and a branch portion 33 extending in the circumferential direction R to connect the expansion portion 31 and the reduction portion 32. The branch portion 33 extends from the expansion portion 31 in the circumferential direction R and branches into a plurality of branch flow paths 330. The branch portion 33 can also be understood as a collection of multiple branch flow paths 330. Because the expansion portion 31 and the reduction portion 32 are separated by a partition wall 34, the expansion portion 31 and the reduction portion 32 are not directly connected. All refrigerant flowing from the supply port 21 into the expansion portion 31 flows through the branch portion 33, then flows into the reduction portion 32, and is discharged from the discharge port 22.

[0026] Figure 3 The shape (refrigerant flow path shape) 30S of the refrigerant flow path 30 is shown in a three-dimensional diagram. The refrigerant flow path shape 30S is a spatial shape, and such a refrigerant flow path shape 30S is formed inside the motor housing 20. That is, the refrigerant flow path 30 is composed of various wall portions inside the motor housing 20, including the supply port 21 and the discharge port 22, and the refrigerant flow path shape 30S is a space divided by the above-mentioned wall portions. Therefore, the refrigerant flow path shape 30S has a supply port shape 21S, a discharge port shape 22S, an expansion portion shape 31S, a branch portion shape 33S, and a reduction portion shape 32S corresponding to the supply port 21, the discharge port 22, the expansion portion 31, the branch portion 33, and the reduction portion 32, respectively. In the gap 34S between the expansion portion shape 31S and the reduction portion shape 32S, there is a partition wall 34 existing in the motor housing 20.

[0027] The refrigerant flow path shape 30S can also be interpreted as a core 50 used to manufacture the motor housing 20. Although details are omitted, the motor housing 20 can be cast by assembling the core 50 in a mold for manufacturing cylindrical components and injecting molten metal material into the mold. The core 50 is formed using, for example, salt or sand. After the metal material solidifies, the core 50 is broken and removed from the motor housing 20 after it is removed from the mold. As a result, the motor housing 20 is left with a space having the same shape as the core 50, namely, the refrigerant flow path shape 30S.

[0028] The following descriptions will focus on the components that constitute the refrigerant flow path 30 and the spaces defined by these components, without explicitly distinguishing them. Therefore, the description of the refrigerant flow path shape 30S also refers to the description of the refrigerant flow path 30. Similarly, the descriptions of the supply port shape 21S, discharge port shape 22S, expansion portion shape 31S, branch portion shape 33S, and reduction portion shape 32S also refer to the descriptions of the supply port 21, discharge port 22, expansion portion 31, branch portion 33, and reduction portion 32, respectively.

[0029] like Figure 3 As shown, the expansion portion shape 31S extends from the supply port shape 21S in the axial direction while extending in the circumferential direction R. That is, the expansion portion 31 extends from the supply port 21 in the circumferential direction R, and the axial width is gradually expanded to connect with the branch portion 33. The branch portion shape 33S extends from the expansion portion shape 31S in the circumferential direction R, and branches into a plurality of branch flow paths. The reduction portion shape 32S extends in the circumferential direction R while reducing in the axial direction from the position connected to the branch portion shape 33S to connect with the discharge port shape 22S. The axial width of each of the expansion portion 31 and the reduction portion 32 at the position connected to the branch portion 33 can be understood to be approximately the same as the axial width of the branch portion 33. In addition, the width of the branch portion 33 in the axial direction can be understood to be approximately constant.

[0030] Figure 4 The expanded portion shape 31S is shown in a perspective view from a radially inner side. The arrow indicated by the reference numeral D indicates a direction D parallel to the motor axis Z. Therefore, the direction D can be regarded as the axial direction. Figure 5 It is a cross-sectional view of the expanded portion 31 in a section perpendicular to the axial direction.

[0031] According to this embodiment, the expansion portion 31 has at least one protrusion 35 extending in the axial direction and narrowing the width of the refrigerant flow path 30 in the radial direction. Figure 4 、 5, an example is shown in which the expansion portion 31 has two protrusions 35, but the number of protrusions 35 may be one or three or more. It is also possible to distinguish between certain protrusions 35 by referring to them as first protrusions 35a and other protrusions 35 as second protrusions 35b. As an example, with the supply port 21 as a reference, the downstream protrusion 35 is referred to as the first protrusion 35a, and the upstream protrusion 35 is referred to as the second protrusion 35b. However, the positional relationship between the first protrusion 35a and the second protrusion 35b may also be reversed.

[0032] The protrusion 35 extending in the axial direction is not limited to the state where its longitudinal direction is parallel to the axial direction, but may also be substantially extended in the axial direction. For example, the longitudinal direction of the protrusion 35 may be inclined relative to the axial direction within a predetermined angle range.

[0033] like Figure 5 As shown in FIG. 1 , a portion of the inner wall portion 23 is protruded radially outward in the expansion portion 31, thereby forming a first protrusion 35a and a second protrusion 35b. Figure 4 As shown, a portion of the expansion portion shape 31S becomes a first protrusion shape 35aS corresponding to the first protrusion 35a, and a second protrusion shape 35bS corresponding to the second protrusion 35b. As a spatial shape, the first protrusion shape 35aS and the second protrusion shape 35bS are as shown in FIG. Figure 4 As shown in FIG, the shape of the object, that is, the shape of the first protrusion 35a and the second protrusion 35b of the inner wall portion 23, is as shown in FIG. Figure 5 Furthermore, at least one protrusion 35 may be a portion of the outer wall portion 24 that protrudes radially inward.

[0034] according to Figure 4 According to the shape of the first protrusion 35aS and the shape of the second protrusion 35bS, it can be understood that the first protrusion 35a and the second protrusion 35b are formed continuously from one end to the other end of the expansion portion 31 in the axial direction. However, at least one of the protrusions 35 may be configured such that there is a lack of continuity in at least one location from one end to the other end of the expansion portion 31 in the axial direction. In addition, when the expansion portion 31 has a plurality of protrusions 35, the protrusion heights of the respective protrusions 35 may be the same or different. Figure 5 In the example, the protrusion height of the first protrusion 35a in the radial direction is the same as the protrusion height of the second protrusion 35b in the radial direction.

[0035] Figure 6 and Figure 5 Similarly, it is a cross-sectional view of the expansion portion 31 in a cross-section perpendicular to the axial direction. Figure 6 , only for Figure 5The differences are explained. Figure 6 In the example, the radial protrusion height of the first protrusion 35a is different from the radial protrusion height of the second protrusion 35b. Specifically, the protrusion height of the first protrusion 35a is higher than the protrusion height of the second protrusion 35b. Alternatively, the protrusion height of the second protrusion 35b may be higher than the protrusion height of the first protrusion 35a.

[0036] according to Figure 5 、 6 For example, the expanded portion 31 can be roughly divided into three ranges in the circumferential direction R by the first protrusion 35a and the second protrusion 35b. Here, the range of the expanded portion 31 downstream of the first protrusion 35a is referred to as the first range 36. Furthermore, the range of the expanded portion 31 upstream of the first protrusion 35a and downstream of the second protrusion 35b is referred to as the second range 37, and the range upstream of the second protrusion 35b is referred to as the third range 38. In a configuration without the second protrusion 35b, the range of the expanded portion 31 upstream of the first protrusion 35a becomes the second range 37.

[0037] according to Figure 5 、 6 As can be seen, the radial widths of the second and third ranges 37 and 38 are greater than those of the first range 36. The radial widths of the first, second, and third ranges 36, 37, and 38 can also be considered the radial distances between the inner wall portion 23 and the outer wall portion 24. This ensures the strength of the core 50. The radial width of the expanded portion 31S is narrowed at the locations of the first and second protruding portions 35aS and 35bS. Therefore, to compensate for the reduced strength of the core 50 caused by these narrowed portions, the thickness of the core 50 is appropriately set. As a result, the radial widths of the second and third ranges 37 and 38 are greater than those of the first range 36. Furthermore, the radial widths of the branching portion 33 and the constricted portion 32 in the refrigerant flow path 30 can be considered to be the same as those of the first range 36. Alternatively, the radial widths can be unified across the entire refrigerant flow path 30 to match the required widths of the second and third ranges 37 and 38.

[0038] Figure 7 The perspective view is shown from the radially inner side. Figure 4 Different examples of the expansion portion shape 31S. Figure 7 The method of viewing pictures and Figure 4 The same method of viewing pictures is used for Figure 7 , omitted with Figure 4 Common description. Figure 7 , the expansion portion shape 31S has a first protrusion shape 35aS. That is, according to Figure 7 , it can be understood that the expansion portion 31 has at least the first protrusion 35a. Figure 7 The first protrusion 35aS is partially curved relative to the axial direction. That is, the first protrusion 35a is curved at least at one location in the axial direction. The first protrusion 35a may have multiple curved locations. Of course, other protrusions 35 such as the second protrusion 35b may also be curved.

[0039] Further, according to Figure 7 The first protrusion shape 35aS has a first section shape 40S and a second section shape 41S in the axial direction. The depths of the first section shape 40S and the second section shape 41S are different from each other. Figure 7 , it can be understood that the first protrusion 35a has a first section corresponding to the first section shape 40S and a second section corresponding to the second section shape 41S in the axial direction, and the protrusion height of the first section in the radial direction is different from the protrusion height of the second section in the radial direction. Of course, other protrusions 35 such as the second protrusion 35b may also have multiple sections with different protrusion heights.

[0040] The characteristic that a single protrusion 35 is curved and the characteristic that a single protrusion 35 has multiple sections with different protrusion heights can be independently understood. For example, the first protrusion 35a may be uncurved and have multiple sections with different protrusion heights. Alternatively, the first protrusion 35a may be curved and have a constant protrusion height.

[0041] Figure 8 A portion of the branch portion 33 is shown in a perspective view. The branch portion 33 includes a plurality of columnar portions 39 disposed at positions separated from each other in the axial direction and the circumferential direction R. The plurality of columnar portions 39 extend radially to connect the inner wall portion 23 and the outer wall portion 24 of the motor housing 20. Figure 8 In the figure, the outer wall portion 24 and the end wall portions 25 and 26 of the motor housing 20 are omitted for the sake of visibility. Figure 8 The cross section of the columnar portion 39 perpendicular to the radial direction is circular. Therefore, the columnar portion 39 can be understood as a cylinder. However, the cross section of the columnar portion 39 may be a polygonal shape such as a hexagon or an octagon.

[0042] Due to the presence of the plurality of columnar portions 39, the branch portion 33 branches into a plurality of branch flow paths 330. That is, the plurality of branch flow paths 330 repeatedly separate and merge with each other, and connect the expansion portion 31 and the contraction portion 32. Figure 8 It can be seen that for Figure 3 、 4Each of the plurality of hole shapes 39S of the branch portion shape 33S shown in FIG. 7 has a columnar portion 39 in the motor housing 20. Figure 2 As shown, each cross section present at a constant interval in the axial direction in the branch portion 33 can be understood as a cross section of each columnar portion 39 .

[0043] Figure 9 A portion of the branch portion shape 33S is shown from a radially oriented viewpoint. Figure 9 For example, the plurality of hole shapes 39S of the branch portion shape 33S are elliptical shapes that are longer in the circumferential direction R. That is, as shown in FIG. Figure 9 As can be understood, at least one of the plurality of columnar portions 39 in the branch portion 33 may have an elliptical cross-section perpendicular to the radial direction.

[0044] exist Figure 10 In the figure, the structure of the motor housing 20 is simply shown from the radially outer side. However, the priority is given to visibility. Figure 10 The outer side wall portion 24 is omitted in the upper portion of the inner portion. Figure 10 The double-dashed circle in FIG represents the position of the supply port 21 and the discharge port 22. Figure 10 In the figure, a cross-sectional view of the branch portion 33 in a section perpendicular to the circumferential direction R is shown in the lower part.

[0045] The branch portion 33 may not have the structure of the plurality of columnar portions 39 described so far, but may have a structure as follows: Figure 10 The structure has multiple middle wall portions 42 as in the example. The multiple middle wall portions 42 respectively connect the inner wall portion 23 and the outer wall portion 24, and extend in the circumferential direction R. In addition, the middle wall portions 42 are separated from each other in the axial direction. Due to the presence of such multiple middle wall portions 42, the branch portion 33 branches into multiple branch flow paths 330. The branch flow paths 330 separated by the middle wall portion 42 respectively connect the expansion portion 31 and the reduction portion 32. The multiple middle wall portions 42 basically extend along the entire range of the branch portion 33 in the circumferential direction R. However, as in Figure 10 As shown in the example, the starting position of each of the plurality of middle wall portions 42 on the expansion portion 31 side may be at least partially offset in the circumferential direction R. In addition, the middle wall portion 42 may not be parallel to the circumferential direction R but may be slightly inclined thereto.

[0046] Further, according to Figure 10For example, the expansion portion 31 includes a throttle portion 43 in a portion of the circumferential direction R. The throttle portion 43 is a region where the ratio of axial expansion relative to changes in position in the circumferential direction R is smaller than that of other portions of the expansion portion 31. The ratio of axial expansion relative to changes in position in the circumferential direction R can also be referred to as the expansion rate of the expansion portion 31. Of course, the configuration of the expansion portion 31 having the throttle portion 43 can also be applied to the configuration of the branch portion 33 having the columnar portion 39.

[0047] exist Figure 10 Although not described in the specification, according to the present embodiment, the expansion portion 31 has one or more protrusions 35 as described above. The positional relationship between the protrusions 35 and the throttle portion 43 can be various. In the expansion portion 31, the throttle portion 43 can be located upstream of a certain protrusion 35 or downstream of the protrusion 35. Alternatively, at least one protrusion 35 can be formed in the throttle portion 43. For example, the throttle portion 43 can be formed in Figure 5 、 6 The second range 37 is shown. Furthermore, the expansion portion 31 may have a shape having the throttle portions 43 at a plurality of positions in the circumferential direction R.

[0048] Thus, according to this embodiment, the cooling structure of the axially extending motor 10 includes: a refrigerant flow path 30 through which refrigerant flows in the circumferential direction R of the motor 10; and a supply port 21 for supplying refrigerant to the refrigerant flow path 30. The refrigerant flow path 30 includes: a flared portion 31 that axially expands from the supply port 21 and extends in the circumferential direction R; and a branch portion 33 that extends from the flared portion 31 in the circumferential direction R and branches into a plurality of branch flow paths 330. The flared portion 31 includes a first protrusion 35a that extends axially and narrows the width of the refrigerant flow path 30 in the radial direction of the motor 10.

[0049] According to the above structure, a portion of the refrigerant supplied from the supply port 21 to the expansion portion 31 is blocked by the first protrusion 35a, making it easier for the refrigerant to temporarily accumulate within the expansion portion 31. The refrigerant then flows to a position downstream of the first protrusion 35a and then to the branch portion 33. This temporary accumulation uniformizes the flow resistance acting on the refrigerant in the axial direction within the expansion portion 31. As a result, the flow rate and / or flow velocity of the refrigerant flowing downstream of the first protrusion 35a are uniform at any axial position within the refrigerant flow path 30, thereby reducing uneven cooling of the motor 10.

[0050] According to one embodiment, the expansion portion 31 further includes a second protrusion 35b extending in the axial direction and narrowing the width of the refrigerant flow path 30 in the radial direction of the motor 10. The second protrusion 35b may be located between the supply port 21 and the first protrusion 35a in the circumferential direction R.

[0051] According to the above configuration, since the expansion portion 31 includes the second protrusion 35b in addition to the first protrusion 35a, the refrigerant is temporarily retained before flowing to the branch portion 33, thereby further improving the effect of uniformizing the flow rate and / or flow velocity in the axial direction.

[0052] Furthermore, according to one embodiment, the protrusion height of the first protrusion 35 a in the radial direction is different from the protrusion height of the second protrusion 35 b in the radial direction.

[0053] That is, the protrusion heights of the plurality of protrusions 35 may be different. By making the protrusion heights of the first protrusion 35a and the second protrusion 35b different from each other, the flow rate and flow velocity of the refrigerant flowing to the branch portion 33 can be more easily controlled.

[0054] Furthermore, according to one embodiment, the first protrusion 35 a is bent at least at one location in the axial direction.

[0055] According to the above configuration, by forming the first protrusion 35 a into a curved shape, it is easier to control the flow rate and flow velocity of the refrigerant flowing downstream of the first protrusion 35 a.

[0056] According to one embodiment, the first protrusion 35 a has a first section and a second section in the axial direction, and the protrusion height in the radial direction of the first section is different from the protrusion height in the radial direction of the second section.

[0057] According to the above configuration, by changing the protrusion height for each section of the first protrusion 35 a , it is easier to control the flow rate and flow velocity of the refrigerant flowing downstream of the first protrusion 35 a .

[0058] According to one embodiment, the first protrusion 35 a is formed continuously from one end to the other end of the expansion portion 31 in the axial direction.

[0059] According to the above configuration, the flow rate and / or flow velocity of the refrigerant flowing downstream of the first protrusion 35 a can be more reliably made uniform at each position in the axial direction.

[0060] According to one embodiment, the radial width of the portion of the expansion portion 31 upstream of the first protrusion 35 a is greater than the radial width of the portion of the expansion portion 31 downstream of the first protrusion 35 a .

[0061] According to the above configuration, as described above, it can be said that the refrigerant flow path 30 is formed using the core 50 having appropriately ensured strength.

[0062] According to one embodiment, the motor 10 includes a cylindrical member 18 having a refrigerant flow path 30. The cylindrical member 18 includes an inner wall portion 23 that defines the inner circumference of the refrigerant flow path 30, and an outer wall portion 24 that defines the outer circumference of the refrigerant flow path 30. Furthermore, the cylindrical member 18 includes a plurality of columnar portions 39 located at the branch portion 33 and extending between the inner wall portion 23 and the outer wall portion 24.

[0063] According to the above structure, the branch portion 33 is divided into a plurality of branch flow paths 330 by the plurality of columnar portions 39. The cross-section of the columnar portion 39 perpendicular to the radial direction of the motor 10 can have various shapes, such as a circle or a polygon. Furthermore, at least one of the plurality of columnar portions 39 may have an elliptical cross-section perpendicular to the radial direction.

[0064] According to one embodiment, the motor 10 includes a cylindrical member 18 having a refrigerant flow path 30. The cylindrical member 18 includes an inner wall portion 23 that defines the inner circumference of the refrigerant flow path 30, and an outer wall portion 24 that defines the outer circumference of the refrigerant flow path 30. Furthermore, the cylindrical member 18 includes a plurality of intermediate wall portions 42 located at the branch portion 33, connecting the inner wall portion 23 and the outer wall portion 24, and extending in the circumferential direction R. The intermediate wall portions 42 are axially separated from each other.

[0065] According to the above configuration, the branch portion 33 is branched into a plurality of branch flow paths 330 by the plurality of middle wall portions 42 .

[0066] According to one embodiment, the cylindrical member 18 is the motor housing 20 that supports the stator core 11 of the motor 10 from the radially outer side.

[0067] According to the above configuration, when manufacturing the motor housing 20 , by forming the refrigerant flow path 30 in the motor housing 20 , a cooling structure for the motor 10 can be easily realized.

[0068] However, forming the refrigerant flow path 30 between the inner wall portion 23 and the outer wall portion 24 of the motor housing 20 is merely an example. For example, the motor housing 20 as the cylindrical member 18 may be configured without the inner wall portion 23. Furthermore, the refrigerant flow path 30 may be formed between the outer circumferential surface of the stator core 11 and the outer wall portion 24 of the motor housing 20 facing the outer circumferential surface by subjecting either or both of the outer circumferential surface of the stator core 11 and the outer wall portion 24 of the motor housing 20 facing the outer circumferential surface to shaping.

[0069] According to one embodiment, the expansion portion 31 includes a throttle portion 43 at a portion in the circumferential direction R. The throttle portion 43 has a smaller ratio of expansion in the axial direction relative to changes in the circumferential direction R than other portions of the expansion portion 31 .

[0070] According to the above configuration, by providing the throttle portion 43 in a portion of the expansion portion 31 , the refrigerant flow toward the branch portion 33 can be prevented from being excessively dispersed toward both axial ends, while ensuring an appropriate flow rate in the axial center.

[0071] While specific examples of the technology disclosed in this specification have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples described above. In addition, the usefulness of the technology elements described in this specification or the drawings, whether alone or in various combinations, is not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings is a technology that achieves multiple objectives simultaneously, and achieving one of the objectives itself has technical usefulness.

Claims

1. A cooling structure for a motor extending in an axial direction, wherein: The cooling structure comprises: a refrigerant flow path through which refrigerant flows in a circumferential direction of the motor; and a supply port for supplying the refrigerant to the refrigerant flow path, The refrigerant flow path has: an expansion portion extending from the supply port in the axial direction and in the circumferential direction; as well as a branch portion extending from the expansion portion along the circumferential direction and branching into a plurality of branch flow paths, The expansion portion includes a first protrusion that extends in the axial direction and narrows a width of the refrigerant flow path in a radial direction of the motor.

2. The cooling structure according to claim 1, wherein: The expansion portion further includes a second protrusion extending in the axial direction and narrowing the width of the refrigerant flow path in the radial direction of the motor. The second protrusion is located between the supply port and the first protrusion in the circumferential direction.

3. The cooling structure according to claim 2, wherein: A protrusion height of the first protrusion in the radial direction is different from a protrusion height of the second protrusion in the radial direction.

4. The cooling structure according to claim 1, wherein: The first protrusion is bent at at least one location in the axial direction.

5. The cooling structure according to claim 1, wherein: The first protrusion has a first section and a second section in the axial direction. A protrusion height of the first section in the radial direction is different from a protrusion height of the second section in the radial direction. The cooling structure according to claim 1 , wherein: The first protrusion is formed continuously from one end to the other end of the expansion portion in the axial direction.

7. The cooling structure according to claim 1, wherein: A width of a portion of the expansion portion upstream of the first protrusion in the radial direction is larger than a width of a portion of the expansion portion downstream of the first protrusion in the radial direction.

8. The cooling structure according to claim 1, wherein: The motor includes a cylindrical member provided with the refrigerant flow path. The cylindrical member has: an inner wall portion, the inner wall portion dividing the inner circumferential surface of the refrigerant flow path; an outer wall portion that divides an outer peripheral surface of the refrigerant flow path; and A plurality of columnar portions are located at the branch portion and extend between the inner wall portion and the outer wall portion respectively.

9. The cooling structure according to claim 8, wherein: At least one of the plurality of columnar portions has an elliptical cross-section perpendicular to the radial direction.

10. The cooling structure according to claim 1, wherein The motor includes a cylindrical member provided with the refrigerant flow path. The cylindrical member has: an inner wall portion, the inner wall portion dividing the inner circumferential surface of the refrigerant flow path; an outer wall portion that divides an outer peripheral surface of the refrigerant flow path; and A plurality of middle wall portions are located at the branch portions, respectively connecting the inner wall portion and the outer wall portion, and extending along the circumferential direction. The plurality of middle wall portions are separated from each other in the axial direction.

11. The cooling structure according to any one of claims 8 to 10, wherein: The cylindrical member is a motor housing that supports the stator core of the motor from the radially outer side.

12. The cooling structure according to claim 1, wherein: The expansion portion has a throttle portion at a portion in the circumferential direction, The expansion ratio of the throttle portion in the axial direction relative to the change in the circumferential direction is smaller than that of other positions of the expansion portion.

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