Cooling device for an electric motor

Abstract

The present application provides a kind of motor cooling device, even if motor miniaturization, can supply oil to the lower part of coil end portion.Oil guide (50) has the guide wall (60c) extending along the direction of rotation axis (CL) and extending along the circumferential direction of first cover (42) when observed from the direction of rotation axis (CL), therefore, when oil is supplied to oil guide (50), along the guide wall (60c) of oil guide (50) moves in the direction of rotation axis (CL), and the oil flowing from the front end of guide wall (60c) is supplied to the lower part of coil end portion (24a).Therefore, it can be appropriate to supply oil to the lower part of coil end portion (24a).In addition, since oil guide (50) is provided on the first cover (42) of resolver 30, even if motor (MG) miniaturization, oil guide (50) can be configured to the inner circumferential side of coil end portion (24a).

Description

Technical Field

[0001] This invention relates to a cooling device for electric motors that improves cooling performance. Background Technology

[0002] Various cooling devices have been proposed for cooling electric motors. For example, Patent Document 1 describes a structure in which an inclined wall is provided on the motor housing housing the electric motor, extending toward the permanent magnet or the periphery of the permanent magnet, guiding the refrigerant stirred up by the rotor to the permanent magnet or the periphery of the permanent magnet. The inclined wall extends to the space formed between the coil end and the rotor shaft.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2018-68086 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] However, from the viewpoint of improving the cooling performance of the electric motor, it is desirable to supply refrigerant to the lower part of the coil end protruding from the stator core of the motor. To this end, it is considered to supply refrigerant to the lower part of the coil end by forming an inclined wall as shown in Patent Document 1. However, a structure is proposed in which a rotary transformer for detecting the rotational speed of the motor is arranged in the space between the coil end and the rotor shaft. In this case, it is difficult to arrange the inclined wall in the space. Furthermore, if the electric motor is miniaturized, the space formed between the coil end and the rotary transformer becomes smaller, making it more difficult to install a mechanism for guiding oil at the lower part of the coil end.

[0008] The present invention was made against the background described above, and its object is to provide a cooling device for an electric motor that can supply oil to the lower part of the coil end even when the electric motor is miniaturized.

[0009] Technical solutions for solving the problem

[0010] As the subject of the first invention, (a) a cooling device for an electric motor comprises: an electric motor having a cylindrical stator, a cylindrical rotor disposed on the inner circumference of the stator, and a shaft fixed to the inner circumference of the rotor; a rotary transformer disposed adjacent to the electric motor in the direction of the rotation axis of the electric motor; and a refrigerant supply mechanism for supplying refrigerant to the electric motor; (b) the stator having a cylindrical stator core and a stator coil penetrating the stator core in the direction of the rotation axis, with a coil end formed by a portion of the stator coil protruding from the stator core; (c) the rotary transformer comprising: a rotary transformer stator fixed to a non-rotating component; and a rotary transformer... A transformer rotor; and a rotary transformer coil wound on the stator of the rotary transformer, characterized in that: (d) the stator of the rotary transformer has a cover covering the rotary transformer coil; (e) an oil guide is provided on the cover for supplying refrigerant supplied from the refrigerant supply mechanism to a portion of the coil end located vertically below the axis of rotation; (f) the oil guide has a guide wall extending along the axis of rotation and extending circumferentially along the cover when viewed from the direction of the axis of rotation; and (h) when viewed radially, at least a portion of the guide wall overlaps with the coil end. Furthermore, "located below the axis of rotation" can also be defined as "located on one side radially separated from the axis of rotation, and further radially away from the refrigerant supply mechanism than the other side."

[0011] As the essence of the second invention, the oil guide further comprises: an arcuate wall formed in an arcuate shape along the circumference of the cover; and a protruding wall extending radially from an end of the arcuate wall located below the axis of rotation in the vertical direction, the radial outer edge of the protruding wall being connected to the guide wall.

[0012] As the essence of the third invention, the second invention is characterized in that the oil guide has a second arcuate wall located at a position on the outer periphery of the arcuate wall, formed in such a way as to cover the outer periphery of the arcuate wall, and a cut is formed on the second arcuate wall at a position in the vertical direction above the axis of rotation, the cut being used to guide oil supplied from the refrigerant supply mechanism to the inner periphery of the second arcuate wall.

[0013] As the essence of the fourth invention, it is characterized in that, in the first invention, the guide wall is inclined more towards the motor side in the direction of the rotation axis, and more towards the vertically downward side.

[0014] As the subject of the fifth invention, it is characterized in that, in the first invention, a through hole is formed in the stator of the rotary transformer, extending along the direction of the rotation axis, so that refrigerant released from the refrigerant supply mechanism is supplied to the oil guide through the through hole.

[0015] As the subject of the sixth invention, it is characterized in that, in the first invention, the oil guide is made of resin material and is integrally formed with the cover.

[0016] As the subject of the seventh invention, it is characterized in that, in the first invention, the refrigerant supply mechanism is a cooling pipe arranged vertically above the motor and having a supply hole for discharging refrigerant.

[0017] Invention Effects

[0018] According to the first invention, the oil guide installed in the housing has a guide wall that extends along the direction of the rotation axis and, when viewed from the direction of the rotation axis, extends circumferentially along the housing. When viewed radially, at least a portion of the guide wall extends to overlap with the coil end. Therefore, when refrigerant released from the refrigerant supply mechanism is supplied to the oil guide along the housing, oil moves along the guide wall of the oil guide in the direction of the rotation axis, and the oil flowing down from the front end of the guide wall is supplied to the lower portion of the coil end. Thus, oil can be appropriately supplied to the lower part of the coil end. Furthermore, since the oil guide is provided in the housing of the rotary transformer, the oil guide can be configured even if the electric motor is miniaturized.

[0019] According to the second invention, when oil supplied from the refrigerant supply mechanism reaches the cover, the oil moves downward along the arc-shaped wall. Furthermore, since a protruding wall extending radially from the lower end of the arc-shaped wall is formed, the oil moving downward along the arc-shaped wall collides with the protruding wall, and the direction of oil flow changes to radial along the protruding wall. Here, through the connection between the guide wall and the outer edge of the protruding wall, the radially moving oil moves along the guide wall in the direction of the rotation axis, and the oil flows down from the front end of the guide wall toward the lower part of the coil end. In this way, the oil supplied from the refrigerant supply mechanism is concentrated on the guide wall via the arc-shaped wall and the protruding wall, and the oil is efficiently supplied to the lower part of the coil end.

[0020] According to the third invention, since a second arcuate wall is formed on the outer periphery of the arcuate wall to cover its outer periphery, oil that flies out from the arcuate wall returns to the arcuate wall side through the second arcuate wall, thereby reducing oil outflow from the arcuate wall. Furthermore, since a slit is formed in the second arcuate wall at a location above the axis of rotation, oil supplied from the refrigerant supply mechanism is guided towards the inner periphery of the second arcuate wall through the slit formed therein.

[0021] According to the fourth invention, since the guide wall is inclined more towards the motor side in the direction of the rotation axis and more towards the vertically downward side, the oil reaching the guide wall moves along the direction of the rotation axis due to the inclination of the guide wall. As a result, the oil reaching the guide wall is efficiently supplied to the lower part of the coil end along the guide wall.

[0022] According to the fifth invention, since the oil supplied from the refrigerant supply mechanism is supplied to the cover side through the through hole formed in the stator of the rotary transformer, even if it is difficult to supply oil to the cover side from the gap between the rotary transformer and the coil end, the oil supplied from the refrigerant supply mechanism can be transported to the cover side.

[0023] According to the sixth invention, since the oil guide is integrally formed with the cover, it is possible to avoid the need for additional components to form the oil guide.

[0024] According to the seventh invention, refrigerant can be supplied to the motor from the supply hole of a cooling pipe disposed above the motor in the vertical direction. Attached Figure Description

[0025] Figure 1 This is a cross-sectional view showing the general outline of the electric motor to which the present invention is applied.

[0026] Figure 2 From Figure 1 Observe the diagram of the rotary transformer in the direction of arrow A.

[0027] Figure 3 This diagram shows the pulling directions of the first and second molds used in the manufacture of the first cover. Detailed Implementation

[0028] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Furthermore, in the following embodiments, the drawings have been appropriately simplified or modified, and the dimensional proportions and shapes of the parts may not be accurately depicted.

[0029]

Example

[0030] Figure 1 This is a cross-sectional view showing an outline of the electric motor MG to which the present invention is applied. The electric motor MG is used, for example, as a driving force source in a vehicle. The electric motor MG is arranged with the rotation axis CL as the center. The electric motor MG includes: a cylindrical stator 12 as a non-rotating component; a cylindrical rotor 14 disposed on the inner circumferential side of the stator 12; and a rotor shaft 16 fixed to the inner circumferential surface of the rotor 14. Furthermore, the rotor shaft 16 corresponds to the shaft of the present invention.

[0031] The stator 12 has a stator core 18 formed in a cylindrical shape and multiple stator coils 20 extending through the stator core 18 along the rotation axis CL.

[0032] The stator core 18 is constructed by stacking multiple insulated electromagnetic steel plates along the rotation axis CL. The stator core 18 is fixed to the motor housing 22, a non-rotating component, by bolts (not shown) in a non-rotating manner. On the inner circumferential surface of the stator core 18, radially extending slots (not shown) are formed at equal angular intervals in the circumferential direction. Each slot extends through the rotation axis CL. The stator coil 20 is inserted into each slot, passing through the stator core 18 in the rotation axis CL direction. Furthermore, a pair of coil ends 24a and 24b are formed from the portions of the stator coil 20 protruding from the stator core 18 along the rotation axis CL. Each coil end 24a and 24b is arranged in a ring shape along the circumference of the stator core 18.

[0033] The rotor 14 includes a cylindrical rotor core 26. The rotor core 26 is constructed by stacking multiple insulated electromagnet plates along the rotation axis CL. A rotor shaft 16 is integrally fixed to the inner circumferential surface of the rotor core 26. The rotor shaft 16 is cylindrical and is supported by bearings 28 and the like at its outer circumferential end along the rotation axis CL, enabling it to rotate about the rotation axis CL.

[0034] A rotary transformer 30 is disposed adjacent to the motor MG in the direction of the rotation axis CL. The rotary transformer 30 is disposed between the motor housing 22 and the motor MG in the direction of the rotation axis CL. The rotary transformer 30 functions as a rotation speed sensor for detecting the rotational speed of the motor MG.

[0035] The rotary transformer 30 includes: a rotary transformer stator 32 formed in the shape of a circular plate; a rotary transformer rotor 34 in the shape of a circular plate disposed on the inner periphery of the rotary transformer stator 32; and a rotary transformer coil 36 wound on the rotary transformer stator 32.

[0036] The rotary transformer stator 32 is fastened to the rotary transformer support 56, which protrudes from the motor housing 22 along the rotation axis CL, by bolts (not shown). Therefore, the rotary transformer stator 32 is fixed to the motor housing 22, which is a non-rotating component. Furthermore, an elongated hole 40 is formed in the rotary transformer stator 32, extending through the rotary transformer stator 32 along the rotation axis CL. Multiple elongated holes 40 are formed at equal angular intervals along the circumference of the rotary transformer stator 32, and when viewed from the rotation axis CL, they are elongated in shape along the circumference of the rotary transformer stator 32 (see reference). Figure 2 Furthermore, the elongated hole 40 corresponds to the through hole of the present invention.

[0037] The rotary transformer rotor 34 is fixed to the outer circumferential surface of the rotor shaft 16 via its inner circumferential surface and rotates integrally with the rotor shaft 16. The rotary transformer coil 36 is wound through a through hole (not shown) formed in the rotary transformer stator 32.

[0038] The rotary transformer stator 32 has a cover 38 that protects the rotary transformer coil 36 wound on the rotary transformer stator 32. The cover 38 is formed in a ring shape such that the rotary transformer coil 36 wound on the rotary transformer stator 32 is covered in its entire circumference. The cover 38 is made of resin material.

[0039] The cover 38 is composed of a first annular cover 42 and a second annular cover 44. The first cover 42 covers the rotary transformer coil 36, which protrudes from the rotary transformer stator 32 toward the motor MG in the direction of the rotation axis CL. The second cover 44 covers the rotary transformer coil 36, which protrudes from the rotary transformer stator 32 toward the bearing 28 in the direction of the rotation axis CL. Both the first cover 42 and the second cover 44 are positioned on the inner circumferential side of the coil end 24a of the motor MG. Furthermore, the first cover 42 corresponds to the cover of the present invention.

[0040] Next, the cooling device 46 for cooling the coil end 24a of the electric motor MG will be described. The cooling device 46 includes: a cooling pipe 48, which, in the assembled state, is vertically positioned above the electric motor MG; and an oil guide 50, which guides oil, which serves as refrigerant, discharged from the cooling pipe 48 to the coil end 24a. Furthermore, in this specification, the assembled state corresponds to the state assembled on a horizontal plane. Therefore, in… Figure 1 In the assembled state shown, the top of the paper corresponds to the top of the plumb line.

[0041] The cooling pipe 48 is arranged parallel to the rotation axis CL of the electric motor MG along its length. Oil drawn by an oil pump (not shown) is supplied to the cooling pipe 48. A first supply hole 52 and a second supply hole 54 are formed on the cooling pipe 48 at positions opposite to the electric motor MG in the circumferential direction. Therefore, the oil supplied to the cooling pipe 48 is discharged from the first supply hole 52 and the second supply hole 54 located above the electric motor MG and supplied to the electric motor MG. Furthermore, the first supply hole 52 and the second supply hole 54 correspond to the supply holes of the present invention, and the cooling pipe 48 with the first supply hole 52 and the second supply hole 54 corresponds to the refrigerant supply mechanism of the present invention.

[0042] When viewed radially around the axis of rotation CL, the first supply hole 52 is formed along the length of the cooling pipe 48 at a position overlapping with the coil end 24a. Therefore, as indicated by the arrow, oil discharged from the first supply hole 52 is supplied to the upper part of the coil end 24a in the vertical direction, specifically cooling the upper part of the coil end 24a. Additionally, the oil that has cooled the upper part of the coil end 24a moves downwards along the coil end 24a. Here, as the oil that has cooled the upper part of the coil end 24a moves to the lower part of the coil end 24a, the oil temperature rises, thus reducing the heat dissipation of the oil and making it difficult to properly cool the lower part of the coil end 24a. As a result, the temperature at the lower part of the coil end 24a tends to be higher than the temperature at the upper part of the coil end 24a.

[0043] In contrast, the cooling device 46 is configured such that oil discharged from the second supply hole 54 is supplied to the lower part of the coil end 24a via the oil guide 50. Viewed radially from the axis of rotation CL, the second supply hole 54 is formed along the length of the cooling pipe 48 at a position overlapping with the rotary transformer support 56 that holds the rotary transformer stator 32. The rotary transformer support 56 is part of the motor housing 22 and protrudes from the wall of the motor housing 22 toward the rotary transformer 30.

[0044] As indicated by the arrow, oil discharged from the second supply hole 54 is supplied to the rotary transformer seat surface 58 formed by the rotary transformer support 56. The oil supplied to the rotary transformer seat surface 58 moves toward the first cover 42 side through the elongated hole 40 formed in the rotary transformer stator 32. The elongated hole 40 is formed in an elongated shape to adjust the assembly position of the rotary transformer stator 32. In addition, multiple elongated holes 40 are formed in the circumferential direction of the rotary transformer stator 32. The rotary transformer seat surface 58 is formed at the same height as the uppermost elongated hole 40 in the vertical direction in the assembled state. Therefore, the oil moves toward the first cover 42 side through the uppermost elongated hole 40 in the vertical direction in the assembled state. In this way, since the oil moves through the elongated hole 40, it is not necessary to form additional holes for the oil to pass through. Furthermore, the rotary transformer stator 32 is fastened to the motor housing 22 by bolts using other elongated holes 40 besides the elongated hole 40 through which the oil passes.

[0045] As described above, the elongated hole 40, located at the uppermost point in the vertical direction in the assembled state, is used as a supply hole for oil supply. That is, oil, configured to be discharged from the second supply hole 54 of the cooling pipe 48, is supplied from the rotary transformer seat surface 58 of the rotary transformer support 56 through the aforementioned elongated hole 40 to the first cover 42 side (i.e., the oil guide 50 side). Therefore, even when the rotor shaft 16 and the coil end 24a are blocked by the rotary transformer 30, oil can still be supplied to the first cover 42 side, i.e., the inner circumference side of the coil end 24a, via the elongated hole 40.

[0046] Oil passing through the elongated hole 40 moves toward the first cover 42 and is supplied to the lower part of the coil end 24a via the oil guide 50 provided on the first cover 42. The oil guide 50 is provided to supply oil discharged from the second supply hole 54 of the cooling pipe 48 to the portion of the coil end 24a located in the vertical direction below the rotation axis CL (i.e., the lower part of the coil end 24a) in the assembled state. The oil guide 50 is made of resin material and is integrally formed with the first cover 42. The oil guide 50 extends from the first cover 42 toward the motor MG side along the rotation axis CL. In addition, when the oil guide 50 is viewed radially with respect to the rotation axis CL, at least a portion of the oil guide 50 in the rotation axis CL direction extends to a position overlapping with the coil end 24a.

[0047] Figure 2 From Figure 1 The diagram shows the rotary transformer 30 in its assembled state, viewed in the direction of arrow A. Figure 2 In the middle, the top of the paper corresponds to the top of the vertical axis in the assembled state. Additionally, Figure 2 The arrow shown indicates the flow of oil discharged from the second supply hole 54 of the cooling pipe 48. Furthermore, in Figure 2 In the diagram, the coil end 24a is indicated by a single-dot dash. Additionally, Figure 2 The BB cross-sectional view shown is... Figure 1 The corresponding sectional view.

[0048] like Figure 2 As shown, in the stator 32 of the rotary transformer, six elongated holes 40 are formed at equal angular intervals in the circumferential direction. Oil discharged from the second supply hole 54 is supplied to the oil guide 50 through the uppermost elongated hole 40 in the vertical direction among these six elongated holes 40.

[0049] The first cover 42 is formed in a ring shape along the circumference of the rotary transformer stator 32, covering the rotary transformer coil 36. An oil guide 50 is erected vertically from the wall of the first cover 42 perpendicular to the rotation axis CL along the direction of the rotation axis CL. The oil guide 50 includes: an inner peripheral guide portion 60 formed along the circumference of the first cover 42; and an outer peripheral guide portion 62 located on the outer peripheral side of the inner peripheral guide portion 60, formed to cover the inner peripheral guide portion 60.

[0050] When viewed from the rotation axis CL, the inner circumferential guide portion 60 includes: an inner circumferential arcuate wall 60a, formed in an arcuate shape along the inner circumferential edge of the first cover 42; a pair of inner circumferential protruding walls 60b extending radially from both ends of the inner circumferential arcuate wall 60a; and a pair of guide walls 60c extending circumferentially along the first cover 42. Furthermore, the inner circumferential guide portion 60 is formed symmetrically with respect to a straight line M passing through the center of the cooling pipe 48 and the rotation axis CL; therefore, the pair of inner circumferential protruding walls 60b and the pair of guide walls 60c are marked with the same reference numerals. Additionally, the inner circumferential arcuate wall 60a corresponds to the arcuate wall of the present invention, and the inner circumferential protruding wall 60b corresponds to the protruding wall of the present invention.

[0051] The inner circumferential arc wall 60a is formed in an arc shape along the inner circumferential edge of the first cover 42, with both ends of the arc extending to a predetermined position below the rotation axis CL. Therefore, at a position above the rotation axis CL, the inner circumferential arc wall 60a is formed in such a way that it covers the entire inner circumferential edge of the first cover 42. When the inner circumferential arc wall 60a is viewed radially from the rotation axis CL, a portion of the inner circumferential arc wall 60a extends in the direction of the rotation axis CL to a position overlapping with the coil end 24a (see reference). Figure 1 ).

[0052] When viewed from the rotation axis CL direction, the inner circumferential protruding wall 60b extends radially outward from one end of the inner circumferential arcuate wall 60a, which is located below the rotation axis CL in the vertical direction. The radial end of the inner circumferential protruding wall 60b extends radially outward beyond the outer periphery of the first cover 42. Furthermore, when viewed from the circumferential direction along the first cover 42, the outer edge of the inner circumferential protruding wall 60b, located radially outward, is inclined such that, in the assembled state, it is further radially outward towards the motor MG side in the rotation axis CL direction. Additionally, when viewed radially from the rotation axis CL, a portion of the inner circumferential protruding wall 60b extends along the rotation axis CL direction to a position overlapping with the coil end 24a.

[0053] The guide wall 60c extends along the outer edge of the inner circumferential protruding wall 60b in the direction of the rotation axis CL. Like the inner circumferential protruding wall 60b, the guide wall 60c, in the assembled state, slopes radially outward the further it is towards the motor MG in the direction of the rotation axis CL. Here, since the guide wall 60c is located below the rotation axis CL in the assembled state, it substantially slopes downward in the vertical direction the further it is towards the motor MG in the direction of the rotation axis CL. The guide wall 60c connects to the outer edge of the inner circumferential protruding wall 60b along the rotation axis CL. Furthermore, when viewed radially from the rotation axis CL, the guide wall 60c extends along the rotation axis CL to a position where a portion of the guide wall 60c in the direction of the rotation axis CL overlaps with the coil end 24a (see reference). Figure 1 ).

[0054] The outer peripheral guide portion 62 includes: an outer peripheral arcuate wall 62a formed on the outer peripheral side of the inner peripheral arcuate wall 60a; a pair of oil-catching walls 62b extending radially from the ends of the walls of the outer peripheral arcuate wall 62a that are cut off by the cut 64 described later; and a pair of outer peripheral protruding walls 62c extending radially from the ends of the outer peripheral arcuate wall 62a formed in the assembled state at a location lower than the rotation axis CL. Furthermore, since the outer peripheral guide portion 62 is formed symmetrically with respect to the straight line M, the pair of oil-catching walls 62b and the pair of outer peripheral protruding walls 62c are respectively marked with the same reference numerals. Additionally, the outer peripheral arcuate wall 62a corresponds to the second arcuate wall of the present invention.

[0055] The outer peripheral arc wall 62a is formed such that it is located on the outer periphery side of the inner peripheral arc wall 60a and covers the outer periphery side of the inner peripheral arc wall 60a. The outer peripheral arc wall 62a is formed in an arc shape along the outer periphery of the first cover 42. In the assembled state, a cut 64 is formed at a position in the vertical direction above the rotation axis CL, which divides a portion of the outer peripheral arc wall 62a. By forming the cut 64, a space is formed in a portion of the circumferential direction of the outer peripheral arc wall 62a. This space is formed at a position that radially overlaps with the uppermost elongated hole 40 in the vertical direction in the assembled state. That is, the space is formed below the uppermost elongated hole 40 in the vertical direction in the assembled state. Therefore, oil passing through the elongated hole 40 can move towards the inner peripheral guide portion 60 through this space. Thus, the cut 64 is formed to guide the oil supplied from the cooling pipe 48 to the inner periphery side of the outer peripheral arc wall 62a.

[0056] The oil-catching wall 62b extends radially from the end of the outer peripheral arcuate wall 62a, which is cut by the notch 64. When viewed from the rotation axis CL direction, the oil-catching wall 62b extends radially outward from the inner circumference of the coil end 24a, and a position where an elongated hole 40 is formed radially is formed. Furthermore, the oil-catching wall 62b extends to a position near the coil end 24a in the rotation axis CL direction.

[0057] The outer peripheral protruding wall 62c extends radially outward from the end of the outer peripheral arcuate wall 62a located below the rotation axis CL. When viewed circumferentially along the first cover 42, the radial outer edge of the outer peripheral protruding wall 62c is inclined such that, in the assembled state, it is located radially outward the further towards the motor MG in the direction of the rotation axis CL. The guide wall 60c connects to the outer edge of the outer peripheral protruding wall 62c along the rotation axis CL. Therefore, both sides of the guide wall 60c in the width direction are connected to the outer edges of the inner peripheral protruding wall 60b and the outer edges of the outer peripheral protruding wall 62c. Thus, as Figure 2 As shown, a roughly U-shaped oil passage is formed by the inner circumferential protruding wall 60b and the outer circumferential protruding wall 62c on both sides of the guide wall 60c. Furthermore, when the oil passage including the guide wall 60c is viewed radially along the rotation axis CL, the oil passage extends along the rotation axis CL to a position that overlaps with the coil end 24a.

[0058] Next, the flow of oil supplied from cooling pipe 48 will be explained. Figure 2 The arrows indicate the flow of oil discharged from the second supply hole 54. The oil discharged from the second supply hole 54 reaches the rotary transformer base surface 58 (see reference). Figure 1 ), and is supplied to the first cover 42 side through the elongated hole 40.

[0059] Oil reaching the first cover 42 side is supplied to the inner circumferential arcuate wall 60a side of the inner circumferential guide 60 through the space formed by the cut 64 of the outer circumferential arcuate wall 62a. At this time, oil flowing out of the elongated hole 40 is reliably captured by the oil-capturing walls 62b formed on both sides of the elongated hole 40 relative to the oil passage in the circumferential direction, and the oil is guided to the inner circumferential arcuate wall 60a side.

[0060] The oil reaching the inner circumferential arc wall 60a moves downward along the circumferential wall of the inner circumferential arc wall 60a. The oil moving downward along the circumferential wall 60b collides with the inner circumferential protruding wall 60b, and the direction of oil flow is changed radially outward. Furthermore, the oil flowing radially outward collides with the guide wall 60c, thereby further changing the oil flow direction to the rotation axis CL direction. Therefore, the oil colliding with the guide wall 60c moves along the guide wall 60c in the rotation axis CL direction, flowing down from the front end of the guide wall 60c towards the coil end 24a. At this time, since the guide wall 60c is more inclined vertically downward the closer it is to the motor MG side in the rotation axis CL direction, the oil colliding with the guide wall 60c moves efficiently along the inclined surface of the guide wall 60c in the rotation axis CL direction and is supplied to the lower part of the coil end 24a. Furthermore, when viewed radially from the axis of rotation CL, a portion of the guide wall 60c in the direction of the axis of rotation CL overlaps with the coil end 24a, thus enabling oil supply to the center or vicinity of the coil end 24a in the direction of the axis of rotation CL. The radial overlap L between the guide wall 60c and the coil end 24a (see reference) Figure 1 The value is determined experimentally or by design in advance and set to be supplied from the front end of the guide wall 60c to the center or near the rotation axis CL of the coil end 24a.

[0061] Furthermore, the guide wall 60c is formed at a position offset by a predetermined angle θ relative to the lower end of the coil end 24a in the vertical direction when the position of the lower end of the coil end 24a in the circumferential direction of the first cover 42 is set to zero degrees. Therefore, the oil flowing out from the front end of the guide wall 60c is supplied to the portion of the coil end 24a located above the lowermost part in the vertical direction. Therefore, the oil supplied to the coil end 24a is supplied to the portion of the coil end 24a located above the lowermost part in the vertical direction, and moves along the coil end 24a toward the lower end of the coil end 24a. Therefore, the oil in the coil end 24a is... Figure 2 The area enclosed by the dotted line is cooled by oil. The specified angle θ is determined experimentally or by design in advance, and is set as a value for efficiently supplying oil to the part of the coil end 24a where the temperature is prone to rise.

[0062] As a result, cooled oil is directly supplied to the lower part of the coil end 24a, where the temperature is prone to rise. This increases the temperature difference between the coil end 24a and the oil, increases thermal conductivity, and increases the contact area between the coil end 24a and the oil, thus effectively reducing the temperature of the lower part of the coil end 24a. Relatedly, the current applied to the motor MG can be increased, allowing for miniaturization of the motor MG. Therefore, the amount of material required to manufacture the motor MG can be reduced. Furthermore, the limitation on the rated output of the motor MG caused by the temperature of the coil end 24a can be alleviated, enabling further improvement in acceleration performance. Moreover, as the temperature of the coil end 24a decreases, copper losses decrease, which also contributes to improved fuel efficiency.

[0063] Figure 3 This indicates the pulling direction of the first mold 70 and the second mold 72 used in manufacturing the first cover 42. Figure 3 The diagram shows the portion where the guide wall 60c is formed circumferentially on the first cover 42. The first mold 70 is specifically designed to form the outer periphery of the first cover 42 and the portion of the first cover 42 that houses the rotary transformer coil 36 after assembly. The second mold 72 is specifically designed to form the oil guide 50. Figure 3 As shown, considering the inclination of the guide wall 60c, the pull-out direction of the first mold 70 and the second mold 72 is set to the left-right direction of the paper plane as indicated by the arrow. During the manufacturing transition period of the first cover 42, the first mold 70 and the second mold 72 are used to... Figure 3 Moving in the direction indicated by the arrow allows for the formation of an oil guide 50 with an inclined guide wall 60c.

[0064] As described above, according to this embodiment, the oil guide 50 installed on the first cover 42 has a guide wall 60c extending along the rotation axis CL and extending circumferentially along the first cover 42 when viewed from the rotation axis CL. When viewed radially, at least a portion of the guide wall 60c extends to a position overlapping with the coil end 24a in the rotation axis CL direction. Therefore, when oil discharged from the second supply hole 54 of the cooling pipe 48 is supplied to the oil guide 50 along the first cover 42, the oil moves along the guide wall 60c of the oil guide 50 in the rotation axis CL direction, and the oil flowing down from the front end of the guide wall 60c is supplied to the lower portion of the coil end 24a. Thus, oil can be appropriately supplied to the lower part of the coil end 24a. In addition, since the oil guide 50 is provided on the first cover 42 of the rotary transformer 30, even if the motor MG is miniaturized, the oil guide 50 can be positioned on the inner circumferential side of the coil end 24a.

[0065] Furthermore, according to this embodiment, when the oil supplied from the second supply hole 54 of the cooling pipe 48 reaches the first cover 42, the oil moves downward along the inner circumferential arc wall 60a. Additionally, since an inner circumferential protruding wall 60b is formed extending radially from the lower end of the inner circumferential arc wall 60a, the oil moving downward along the inner circumferential arc wall 60a collides with the inner circumferential protruding wall 60b, and the direction of oil flow is changed to radial along the inner circumferential protruding wall 60b. Furthermore, the guide wall 60c is connected to the outer edge of the inner circumferential protruding wall 60b, thereby causing the radially moving oil to move along the guide wall 60c in the direction of the rotation axis CL, and the oil flows down from the front end of the guide wall 60c toward the lower part of the coil end 24a. In this way, the oil supplied from the cooling pipe 48 is concentrated in the guide wall 60c via the inner circumferential arc wall 60a and the inner circumferential protruding wall 60b, and the oil is efficiently supplied to the lower part of the coil end 24a. Furthermore, since an outer peripheral arc wall 62a is formed on the outer peripheral side of the inner peripheral arc wall 60a, covering the outer peripheral side of the inner peripheral arc wall 60a, oil that flies out from the inner peripheral arc wall 60a is returned to the inner peripheral arc wall 60a by the outer peripheral arc wall 62a, thereby reducing oil outflow from the inner peripheral arc wall 60a. Additionally, since a cut 64 is formed in the outer peripheral arc wall 62a at a position above the rotation axis CL, oil supplied from the cooling pipe 48 is guided towards the inner peripheral side of the outer peripheral arc wall 62a through the cut 64 formed therein. Furthermore, since the guide wall 60c slopes downwards towards the motor MG in the rotation axis CL direction, oil reaching the guide wall 60c moves along the rotation axis CL direction due to the slope of the guide wall 60c. As a result, the oil reaching the guide wall 60c is efficiently supplied to the lower part of the coil end 24a along the guide wall 60c. Furthermore, since the oil supplied from the cooling pipe 48 is supplied to the first cover 42 side through the elongated hole 40 formed in the rotary transformer stator 32, even when it is difficult to supply oil to the first cover 42 side from the gap between the rotary transformer 30 and the coil end 24a, the oil supplied from the cooling pipe 48 can still be transported to the first cover 42 side. Additionally, since the oil guide 50 is integrally formed with the first cover 42, it is possible to avoid the need for additional components to form the oil guide 50.

[0066] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is also applicable to other methods.

[0067] For example, in the above embodiment, the outer diameter of the stator 32 of the rotary transformer 30 is larger than the inner circumferential dimension of the coil end 24a. When viewed radially, the stator 32 is positioned in a position that does not overlap with the coil end 24a. However, the present invention is not necessarily limited to this. Specifically, the outer diameter of the stator 32 may also be smaller than the inner circumferential dimension of the coil end 24a, and the rotary transformer 30 may be disposed in the space between the coil end 24a and the rotor shaft 16.

[0068] Furthermore, in the above embodiment, a cooling pipe 48 is disposed above the electric motor MG, and oil is discharged from the first supply hole 52 and the second supply hole 54 formed in the cooling pipe 48. However, the present invention is not limited to this method. For example, an oil supply passage may be formed in the housing covering the upper part of the electric motor MG, and oil may be supplied to the electric motor MG from the supply hole formed in the oil passage. In short, the present invention can be appropriately applied as long as it has a structure that provides a refrigerant supply mechanism for supplying oil to the electric motor MG.

[0069] In addition, in the above embodiments, the guide wall 60c is inclined more vertically downwards as it moves towards the motor MG in the direction of the rotation axis CL, but it is not necessary for the guide wall 60c to be inclined; it can also be formed parallel to the rotation axis CL.

[0070] In addition, in the above embodiment, an oil-catching wall 62b is formed extending radially outward from the end of the portion of the outer peripheral arc wall 62a that is cut off by the cut 64, but the oil-catching wall 62b is not necessarily required, and it can be implemented by removing the oil-catching wall 62b.

[0071] In addition, in the above embodiment, an outer peripheral guide portion 62 is provided on the outer peripheral side of the inner peripheral guide portion 60, but the outer peripheral guide portion 62 can also be removed.

[0072] In addition, in the above embodiment, oil is supplied to the first cover 42 side through an elongated hole 40 formed to adjust the position of the rotary transformer stator 32, but it is not necessarily limited to the elongated hole 40. For example, oil can also be supplied to the first cover 42 side through a dedicated through hole formed inside the rotary transformer stator 32.

[0073] In addition, in the above embodiment, the oil discharged from the second supply hole 54 of the cooling pipe 48 is supplied to the first cover 42 side through the elongated hole 40 of the rotary transformer stator 32, but it is not necessary to supply oil through the elongated hole 40. For example, oil can also be supplied from the gap in the direction of the rotation axis CL formed between the rotary transformer stator 32 and the coil end 24a.

[0074] In addition, in the above embodiments, the first cover 42 and the oil guide 50 are integrally formed, but these first covers 42 and oil guide 50 can also be formed separately and assembled.

[0075] Furthermore, the above is merely one implementation method, and the present invention can be implemented in various ways with modifications and improvements based on the knowledge of those skilled in the art.

[0076] Label Explanation

[0077] 12: Stator;

[0078] 14: Rotor;

[0079] 16: Rotor shaft (shaft);

[0080] 18: Stator core;

[0081] 20: Stator coil;

[0082] 22: Motor housing (non-rotating part);

[0083] 24a: Coil end;

[0084] 30: Rotary transformer;

[0085] 32: Rotary transformer stator;

[0086] 34: Rotor of a rotary transformer;

[0087] 40: Long hole (through hole);

[0088] 42: First cover;

[0089] 46: Cooling device;

[0090] 48: Cooling pipe (refrigerant supply mechanism);

[0091] 50: Oil guide component;

[0092] 52: First supply hole (supply hole);

[0093] 54: Second supply hole (supply hole);

[0094] 60a: Inner circumferential arc wall (arc wall);

[0095] 60b: Inner peripheral protruding wall (protruding wall);

[0096] 60c: Guide wall;

[0097] 62a: Outer circumferential arc wall (second arc wall);

[0098] 64: Incision;

[0099] MG: Electric motor.

Claims

1. A cooling device for an electric motor, the cooling device (46) for the electric motor (MG) comprising: An electric motor (MG) having a cylindrical stator (12), a cylindrical rotor (14) disposed on the inner circumferential side of the stator (12), and a shaft (16) fixed to the inner circumferential surface of the rotor (14). A rotary transformer (30) is disposed adjacent to the electric motor (MG) in the direction of its rotation axis; and The refrigerant supply mechanism (48) supplies refrigerant to the electric motor (MG). The stator (12) has a cylindrical stator core (18) and a stator coil (20) that passes through the stator core (18) along the direction of the rotation axis, and the coil end (24a) is formed by the part of the stator coil (20) that protrudes from the stator core (18). The rotary transformer (30) comprises: a rotary transformer stator (32) fixed to a non-rotating component (22); a rotary transformer rotor (34); and a rotary transformer coil (36) wound around the rotary transformer stator (32), characterized in that... The stator (32) of the rotary transformer has a cover (42) covering the coil (36) of the rotary transformer. An oil guide (50) is provided on the cover (42) for supplying refrigerant supplied from the refrigerant supply mechanism (48) to a portion of the coil end (24a) located vertically below the axis of rotation. The oil guide (50) has a guide wall (60c) that extends along the direction of the rotation axis and, when viewed from the direction of the rotation axis, extends circumferentially along the cover (42). When viewed radially, at least a portion of the guide wall (60c) overlaps with the coil end (24a). The oil guide (50) further comprises: an arcuate wall (60a) formed in an arcuate shape along the circumference of the cover (42); and a protruding wall (60b) extending radially from the end of the arcuate wall (60a) located below the axis of rotation in the vertical direction. The radial outer edge of the protruding wall (60b) is connected to the guide wall (60c). The guide wall (60c) is inclined more towards the motor (MG) side in the direction of the rotation axis and more towards the vertically downward side.

2. The cooling device for the electric motor according to claim 1, characterized in that, The oil guide (50) has a second arcuate wall (62a) located on the outer periphery of the arcuate wall (60a) and formed to cover the outer periphery of the arcuate wall (60a). A cut (64) is formed in the second arcuate wall (62a) at a position above the axis of rotation in the vertical direction. This cut is used to guide the oil supplied from the refrigerant supply mechanism (48) to the inner circumferential side of the second arcuate wall (62a).

3. The cooling device for the electric motor according to claim 1, characterized in that, A through hole (40) is formed in the stator (32) of the rotary transformer, extending along the direction of the rotation axis. The refrigerant discharged from the refrigerant supply mechanism (48) is supplied to the oil guide (50) through the through hole (40).

4. The cooling device for the electric motor according to claim 1, characterized in that, The oil guide (50) is made of resin material. The oil guide (50) is integrally formed with the cover (42).

5. The cooling device for the electric motor according to claim 1, characterized in that, The refrigerant supply mechanism (48) is a cooling pipe that is arranged vertically above the motor (MG) and has supply holes (52, 54) for discharging refrigerant.

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