Cooling structure of electric motor

Abstract

Provided is a cooling structure for an electric motor in which a stator is cooled by a cooling fluid, said stator having a stator yoke in which grooves that open toward the inner peripheral side thereof and are continuous in the axial direction are formed, coils are held inside the grooves, and coil ends protrude on both end sides of the stator yoke in the axial direction. In the cooling structure, an inflow port into which a cooling fluid flows is provided at one end of the stator yoke in the axial direction and further to the outside than the coil end in the radial direction, and an inflow port into which the cooling fluid flows is provided at a position closer to the outer peripheral surface of the stator yoke than to the slot. A cooling flow path through which a cooling fluid flows is formed from one end side toward the other end side in the axial direction of the stator yoke, and one end of the cooling flow path communicates with an inflow port of the stator yoke.

Description

Technical Field

[0001] The present invention relates to a structure for cooling a stator that holds a coil by supplying a cooling fluid such as oil to the stator in an electric motor. Background Art

[0002] A device for cooling a motor is described in U.S. Patent Application Publication No. 2023 / 0008953. This device is configured such that a cooling fluid flows in the axial direction inside a stationary core for cooling. That is, the stationary core is formed by laminating a plurality of annular electromagnetic steel sheets. A plurality of teeth extending toward the center of the stationary core are provided on the inner peripheral side thereof, and coils are held in slots between these teeth. A plurality of cooling flow paths for allowing the cooling fluid to flow are formed in a circumferential direction in an outer peripheral portion that is significantly separated from the slots of the stationary core in the radial direction. That is, through holes are formed in the outer peripheral portion of the electromagnetic steel sheet, and the electromagnetic steel sheets are laminated such that these through holes are connected in the axial direction, thereby forming the cooling flow paths by these through holes. In addition, each electromagnetic steel sheet has a convex portion that protrudes outward in the radial direction, and by laminating the electromagnetic steel sheets, a so-called bead-shaped (bead, rib-shaped) ridge extending in the axial direction is formed in the outer peripheral portion of the stationary core using this convex portion. Inside this ridge, a bolt hole through which a bolt for fastening, connecting, or fixing the electromagnetic steel sheets passes is provided along the axial direction, and an inflow hole is provided in parallel therewith. At a position on the outer peripheral portion of the electromagnetic steel sheet located substantially at the center in the axial direction of the stationary core and facing the cooling flow path, an arc-shaped groove or slit centered on the center of the stationary core is formed, and this groove or slit serves as a header for each cooling flow path. Moreover, a communication portion that connects this groove or slit and the inflow hole is formed. Therefore, when the cooling fluid is supplied to the inflow path by a pump or the like, at a position substantially at the center in the axial direction of the stationary core, the cooling fluid is dispersedly supplied to each cooling flow path via the above-mentioned communication path and the above-mentioned groove or slot. This cooling fluid flows in two directions in the axial direction from a position substantially at the center in the axial direction of the stationary core, and flows out of the cooling flow path at the end of the stationary core and drops onto the coil end. That is, a position substantially at the center in the axial direction of the cooling flow path serves as an inflow portion of the cooling fluid, and both end portions in the axial direction serve as outflow portions. Summary of the Invention

[0003] The temperature of the stationary core rises due to Joule heat generated by the current flowing in the coil and the change in magnetic flux. This heat is transferred to the outer peripheral side in the electromagnetic steel plate and reaches the cooling flow path, and is transported to the outside by the cooling fluid flowing therein. That is, the stationary core is cooled by the cooling fluid from its outer peripheral portion side. However, the heat generation in the stationary core is mainly generated by the coil. On the other hand, in the configuration described in the above-mentioned U.S. Patent Application Publication No. 2023 / 0008953, cooling is performed at the outer peripheral portion away from the coil. Therefore, it is possible that the temperature of the stationary core becomes high due to the heat storage between the coil or the teeth holding the coil and the cooling flow path. In other words, the thermal resistance between the coil and the cooling fluid is large, and there is room for improvement in the cooling effect.

[0004] In addition, with the cooling flow path provided at the outer peripheral portion of the stationary core, the outflow portion of the cooling fluid toward the coil end is located at a position significantly away from the coil end toward its upper side. As a result, the coverage rate of the cooling fluid for the coil end becomes low, and it may not be possible to sufficiently cool the coil end.

[0005] The present invention has been made in view of the above technical problems, and an object thereof is to provide a cooling structure for an electric motor that can improve the cooling performance of a stator having a coil.

[0006] In order to achieve the above object, the present invention provides a cooling structure for an electric motor, which is a cooling structure for an electric motor that cools a stator with a cooling fluid. The stator has a groove that is formed in a stator yoke formed by laminating annular steel plates and opens toward the inner peripheral side of the stator yoke and is continuous in the axial direction, and a coil is held inside the groove and the coil ends protrude from both ends in the axial direction of the stator yoke. The cooling structure is characterized in that

[0007] at one end in the axial direction of the stator yoke and at a position radially outside the coil end, an inlet through which the cooling fluid flows in is provided,

[0008] at a position closer to the groove than to the outer peripheral surface of the stator yoke, a cooling flow path through which the cooling fluid flows is formed from one end side in the axial direction of the stator yoke toward the other end side,

[0009] one end of the cooling flow path communicates with the inlet of the stator yoke, and

[0010] the other end of the cooling flow path opens at the other end side of the stator yoke.

[0011] In the present invention, the opening shape of the cooling flow path may be a shape in which the dimension measured in the circumferential direction of the stator yoke is smaller than the dimension measured in the radial direction of the stator yoke.

[0012] In the present invention, it is possible that the opening shape of the inlet is a shape in which the dimension measured in the radial direction of the stator yoke is smaller than the dimension measured in the circumferential direction of the stator yoke.

[0013] In the present invention, it is possible that

[0014] A header portion is provided, which is an annular space that covers the inlet on one end side in the axial direction of the stator yoke and distributes and supplies the cooling fluid to each of the inlets.

[0015] In the header portion, an outflow hole is formed for supplying the cooling fluid to the coil end protruding on one end side in the axial direction of the stator yoke.

[0016] In the present invention, it is possible that a third steel plate is provided, which is sandwiched between a first steel plate provided with the inlet and a second steel plate formed with the cooling flow path.

[0017] In the third steel plate, a communication hole portion is formed that opens to both the inlet provided in the first steel plate and the cooling flow path provided in the second steel plate.

[0018] The inlet and the cooling flow path are communicated with each other through the communication hole portion.

[0019] According to the present invention, an inlet for supplying a cooling fluid to the inside of the stator yoke is provided on the outer peripheral side with respect to the coil end. Therefore, there is an advantage that interference between the inlet and the coil end can be avoided, and the degree of freedom in designing the shape of the inlet can be increased, such as increasing the shape of the inlet as needed. In addition, a cooling flow path for allowing the cooling fluid to flow inside the stator yoke is provided at a position closer to the slot than to the outer peripheral surface of the stator yoke, that is, a position closer to the coil. Therefore, cooling is performed using the cooling fluid at a position close to the coil that generates heat due to operation. That is, the thermal resistance between the coil and the cooling fluid is small, and as a result, the stator yoke can be effectively cooled. Moreover, the outlet end of the cooling flow path, that is, the outlet, is located at a portion close to the coil end at the other end in the axial direction of the stator yoke. Therefore, the cooling fluid flows down without deviating from the coil end. As a result, the coverage rate of the oil can be increased. In this way, according to the present invention, since the cooling fluid removes a large amount of heat, the cooling performance of the stator can be improved.

[0020] The opening shape of the cooling flow path of the present invention, i.e., the shape when cut by a plane perpendicular to the central axis of the stator yoke, becomes a shape with a small dimension in the circumferential direction. The portion where the cooling flow path is provided is a portion close to the slot (tooth formed with the slot), and is a portion where the magnetic flux is directed in the radial direction of the stator yoke or in a direction close to the radial direction. Therefore, the width or area of the cooling flow path blocking the magnetic flux becomes smaller, and deterioration or decrease of magnetic characteristics can be suppressed.

[0021] Similarly, the opening shape of the inlet of the present invention, i.e., the shape when cut by a plane perpendicular to the central axis of the stator yoke, becomes a shape with a small dimension in the radial direction. The portion where the inlet is provided is a portion on the outer peripheral side of the stator yoke, and is a portion where the magnetic flux is directed in the circumferential direction of the stator yoke or in a direction close to the circumferential direction. Therefore, the width or area of the inlet blocking the magnetic flux becomes smaller, and thus, deterioration or decrease of magnetic characteristics due to the inlet can be suppressed.

[0022] In the present invention, the header portion is formed as an annular void facing each inlet arranged in the circumferential direction at the end portion of the stator yoke in the axial direction, and thus, a cooling fluid is supplied to the header portion. Thereby, the cooling fluid can be distributed and supplied from all the inlets to the cooling flow paths communicating with each of all the inlets. Moreover, the cooling fluid can be dropped from the outflow hole onto the coil end located on the inner peripheral side of the header portion to cool the coil end.

[0023] In the present invention, the inlet, and / or the cooling flow path and the communication hole portion can be formed by opening holes penetrating in the plate thickness direction in an annular steel plate and laminating the steel plates in such a manner that these holes communicate with each other. Therefore, processing and assembly are easy, and in addition, no extra portion protruding to the outside is required, and thus, the overall shape can be simplified. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Hereinafter, the features, advantages, and technical and industrial significance of the exemplary embodiments of the present invention will be described with reference to the drawings, in which the same reference numerals denote the same elements, and:

[0025] Figure 1 is a schematic diagram for explaining the general configuration of the motor targeted in the embodiment of the present invention;

[0026] Figure 2 is a front view showing a part of the stator yoke for explaining an example of the position and opening shape of the inlet, the cooling flow path, and the communication hole portion;

[0027] Figure 3 is a schematic cross-sectional view showing a part of one end portion of the stator yoke in the axial direction;

[0028] Figure 4 A front view of a part of an electromagnetic steel sheet for explaining the direction of magnetic flux;

[0029] Figure 5 A diagram showing an example of the opening shape of the communication hole portion. Detailed implementation mode

[0030] Next, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the embodiments described below are merely examples in the case of implementing the present invention and do not limit the present invention.

[0031] The overall configuration of the motor (motor) 1 in the embodiment of the present invention is shown schematically in Figure 1 Here. The example shown here is a permanent magnet type synchronous motor. Except for the structure for cooling, its basic configuration is substantially the same as that of conventional motors. That is, on the outer peripheral side of the rotor 2, a cylindrical stator 3 is arranged concentrically. The rotor 2 holds a permanent magnet (not shown), and a rotor shaft 4 protruding to both sides in the axial direction thereof is held by a motor housing 6 via bearings 5 so as to be rotatable. The motor housing 6 is a hollow member covering the entire motor 1, and the above-mentioned stator 3 is fixed to its inner peripheral surface.

[0032] The stator 3 is constituted by laminating a plurality of circular thin electromagnetic steel sheets. In the inner peripheral portion of each electromagnetic steel sheet, as shown in part in Figure 2 Grooves 7 opening toward the inner peripheral side are arranged in the circumferential direction. The portions between these grooves 7 become teeth 8. The electromagnetic steel sheets are aligned and laminated in such a manner that these grooves 7 or teeth 8 are arranged in the direction of the central axis of the stator 3, whereby a stator yoke (stationary core) 9 is constituted. In each groove 7, for example, coils connected in series in each of the three phases are arranged, and their folded-back ends (coil ends) 10 protrude from both ends in the axial direction of the stator yoke 9.

[0033] The cooling structure in the embodiment of the present invention is configured to cool the motor 1 (particularly the stator 3 and the coil ends 10) by flowing a cooling fluid C inside the stator yoke 9 configured as described above. If specifically described, Figure 3 A part of both ends in the axial direction of the stator yoke 9 is schematically shown. In a plurality of electromagnetic steel sheets 9a located at the Figure 3 right end of the electromagnetic steel sheets constituting the stator yoke 9, through holes penetrating in the plate thickness direction are provided, and inlets 11 are formed by these through holes. The inlets 11 are as shown in Figure 2As shown, it is formed on the outer peripheral side of the electromagnetic steel sheet (stator yoke 9), more specifically, at a position on the outer peripheral side of the aforementioned coil end 10 so as not to interfere with the coil end 10. Further, the inflow port 11 is, for example, a through portion having an opening width smaller than the maximum width of the tooth 8, and a plurality of the inflow ports 11 are formed at predetermined intervals in the circumferential direction on the outer peripheral portion of the electromagnetic steel sheet (stator yoke 9). The electromagnetic steel sheet 9a provided with the inflow port 11 corresponds to the first steel sheet in the embodiment of the present invention.

[0034] Since the inflow port 11 is provided on the outer peripheral side of the coil end 10, there is little room for interference with the coil end 10. Therefore, the opening area (size) and / or shape of the inflow port 11 can be appropriately set as needed. That is, the degree of freedom in design including the shape of the inflow port 11 is high. Further, the opening shape of the inflow port 11 (the cross-sectional shape when cut by a plane perpendicular to the central axis of the stator yoke 9) can be appropriately determined as needed. However, considering the orientation of the magnetic flux 12 generated in the stator yoke 9, it is preferably set to the shape described below.

[0035] Figure 4 The orientation of the magnetic flux 12 when the stator yoke 9 (electromagnetic steel sheet) is viewed from the axial direction is shown by a curve. In a portion on the outer peripheral side of the tooth 8, the magnetic flux 12 is generated so as to connect the teeth 8 across the slot 7, and in the portion of the tooth 8, the magnetic flux 12 is generated in the direction of its length (the radial direction of the electromagnetic steel sheet or the stator yoke 9). Since the inflow port 11 is a hollow portion through which the cooling fluid C flows, it functions to reduce the portion where the magnetic flux 12 is generated (or flows) and to block the magnetic flux 12. Considering the orientation of such magnetic flux 12, the opening shape of the inflow port 11 is preferably a shape such as a rectangle, an ellipse, or a rhombus in which the dimension in the radial direction is smaller than the dimension in the circumferential direction (or the direction perpendicular to the radial direction) in order to reduce the cross-sectional area perpendicular to the orientation of the magnetic flux 12 (the area facing the magnetic flux 12) while ensuring the area of the inflow port 11 as a flow path. By doing so, it is possible to reduce the influence on the magnetic flux 12 while ensuring the cross-sectional area of the flow path of the cooling fluid C, and to avoid or suppress the deterioration of the magnetic characteristics or the performance of the motor 1.

[0036] In a plurality of other electromagnetic steel sheets 9b adjacent to the electromagnetic steel sheet having the through-hole forming the above-mentioned inlet 11, through-holes elongated in the radial direction of the electromagnetic steel sheet 9b are formed. The communication hole portion 13 is formed by laminating the electromagnetic steel sheets in such a manner that these through-holes overlap in the axial direction. The communication hole portion 13 is provided corresponding to the above-mentioned inlet 11. That is, the communication hole portions 13 are provided at positions in the circumferential direction of the electromagnetic steel sheet that are the same as the position of the inlet 11. In addition, the end portions on the outer peripheral side (the outer side in the radial direction of the electromagnetic steel sheet) of each communication hole portion 13 overlap with the inlet 11. That is, each of the plurality of communication hole portions 13 communicates with the above-mentioned inlet 11. The electromagnetic steel sheet 9b in which the communication hole portion 13 is formed corresponds to the third steel sheet in the embodiment of the present invention.

[0037] A cooling flow path 14 for the cooling fluid C supplied from the inlet 11 via the above-mentioned communication hole portion 13 is formed inside the stator yoke 9. That is, in the electromagnetic steel sheet from the electromagnetic steel sheet in contact with the electromagnetic steel sheet 9b in which the above-mentioned communication hole portion 13 is formed to the other end of the stator yoke 9 ( Figure 3 the left end), through-holes penetrating in the plate thickness direction are formed, and the cooling flow path 14 is formed by laminating the electromagnetic steel sheets in such a manner that these through-holes overlap with each other. The electromagnetic steel sheet 9c in which the cooling flow path 14 is formed corresponds to the second steel sheet in the embodiment of the present invention that sandwiches the electromagnetic steel sheet 9b corresponding to the above-mentioned third steel sheet between itself and the electromagnetic steel sheet 9a corresponding to the above-mentioned first steel sheet.

[0038] The cooling flow path 14 is provided at a position closer to the above-mentioned slot 7 or tooth 8 than to the outer peripheral surface of the electromagnetic steel sheet or the stator yoke 9. For example, as Figure 2 shown, a part of the inner peripheral side enters the tooth 8 and is provided at a position overlapping the slot 7 when viewed in the circumferential direction. In addition, the open end of the cooling flow path 14 on one end side ( Figure 3 the right end side) in the axial direction of the stator yoke 9 is located at a position corresponding to the inner end portion in the radial direction of the aforementioned communication hole portion 13. That is, the cooling flow paths 14 are arranged in the circumferential direction in the same number as the teeth 8, and each cooling flow path 14 communicates with the communication hole portion 13. Therefore, one end of the above-mentioned inlet 11 and the cooling flow path 14 are connected via the communication hole portion 13. In addition, the other end of the cooling flow path 14 ( Figure 3 the left end) opens on the side surface of the stator yoke 9 to form an outlet 15. Therefore, the outlet 15 is disposed close to the coil end 10, such as directly above the coil end 10, so that the outflowing cooling fluid C drops onto the coil end 10.

[0039] The opening shape of these cooling flow paths 14 (the cross-sectional shape when cut by a plane perpendicular to the central axis of the stator yoke 9) can be appropriately determined as needed, similarly to the above-described inlet 11. However, considering the orientation of the magnetic flux 12 generated in the stator yoke 9, it is preferably set to the shape described below. As described with reference to Figure 4 In the part close to the tooth 8, the orientation of the magnetic flux 12 becomes the longitudinal direction of the tooth 8 (the radial direction of the electromagnetic steel sheet or the stator yoke 9) or a direction close thereto. In addition, the cooling flow path 14 is a hollow part through which the cooling fluid C flows, and functions to reduce the part where the magnetic flux 12 is generated (or flows through) and block the magnetic flux 12. Therefore, the opening shape of the cooling flow path 14, in order to reduce the cross-sectional area perpendicular to the orientation of the magnetic flux 12 (the area facing the magnetic flux 12) while ensuring the area of the cooling flow path 14 as a flow path, is preferably as shown in Figure 2 a rectangle, an ellipse, a rhombus, or the like whose dimension in the circumferential direction is smaller than the dimension in the radial direction (the so-called longitudinally long shape in Figure 2 ). By doing so, while ensuring the cross-sectional area of the flow path for the cooling fluid C, the influence on the magnetic flux 12 can be reduced, and a decrease in magnetic characteristics or the performance of the motor 1 can be avoided or suppressed.

[0040] In addition, the above-described communication hole portion 13 only needs to function to connect the inlet 11 and the cooling flow path 14, and therefore, an appropriate opening shape can be set within this range. In Figure 2 a trapezoidal communication hole portion 13 with a narrow width on the inner peripheral side is shown, but in addition to this, for example, it can also be as shown in Figure 5 a shape 13A in which the outer peripheral side portion is large and the inner peripheral side portion is thin, a T-shaped 13B, etc.

[0041] Next, the configuration for supplying the cooling fluid C to each inlet 11 will be described. On the end face of the stator yoke 9 where each inlet 11 is opened, a header portion 16 is provided as an empty space covering each inlet 11. That is, the header portion 16 is configured as an annular empty space delimited by a guiding member 17 disposed between the inlet 11 and the coil end 10 and a part of the motor housing 6. The guiding member 17 is integrally cylindrical and is sandwiched between the side surface of the electromagnetic steel sheet ([[]]END]] Figure 3 the rightmost electromagnetic steel sheet in [[[]]) where the inlet 11 is formed and the inner side surface of the motor housing 6 facing the side surface, and becomes a liquid-tight state by interposing a sealing member such as an O-ring between either the side surface of the electromagnetic steel sheet and the inner side surface of the motor housing 6. Therefore, the outer peripheral side portion of the cylindrical portion 17a in the guiding member 17 becomes the header portion 16 as an empty space closed together with the motor housing 6, and each inlet 11 opens toward the header portion 16.

[0042] Further, a pump 18 for supplying a cooling fluid (e.g., oil) C is connected to the header portion 16. In addition, an outflow hole 19 for supplying the cooling fluid C toward the coil end 10 on the inner peripheral side thereof is formed in the cylindrical portion 17a of the guide member 17. Further, the header portion 16 may communicate with the gap between the outer peripheral surface of the stator yoke 9 and the inner peripheral surface of the motor housing 6, or may be in a liquid-tight state conversely. In order to make it in a liquid-tight state, an appropriate seal such as an O-ring may be interposed between the end surface in the axial direction of the stator yoke 9 and the motor housing 6.

[0043] Next, the operation of the above cooling structure will be described. When electric current is applied to the coil to rotate the electric motor 1 or when the rotor 2 is forcibly rotated by an external force to cause the electric motor 1 to function as a generator, heat is generated in the coil. In addition, heat is generated due to the change in magnetic flux in the stator yoke 9. In this case, when the cooling fluid C such as oil is supplied to the header portion 16 by the pump 18, the cooling fluid C is dispersedly supplied to the inflow port 11 that opens toward the header portion 16. The cooling fluid C is sent to the cooling flow path 14 that extends in the axial direction inside the stator yoke 9 through the communication hole portion 13. Since the cooling flow path 14 is provided at a position close to the slot 7 or the coil as described above, the cooling fluid C flows near the coil with a large amount of heat generation and takes heat from its surroundings. That is, since the coil is close to the cooling fluid C and the thermal resistance therebetween becomes small, the coil can be efficiently cooled via the stator yoke 9.

[0044] The cooling fluid C takes heat in this way to cool the coil and the stator yoke 9, and flows toward the other end in the axial direction of the stator 3, and flows out from the outflow port 15 at the other end. The cooling flow path 14 is formed at a position close to the coil as described above. Therefore, the outflow port 15 as its open end is also close to the coil end 10, so that the cooling fluid C ejected from the outflow port 15 is directly sprayed onto the coil end 10, and the coverage rate of the cooling fluid C on the coil end 10 becomes high. That is, the cooling fluid C can be efficiently sprayed onto the coil end 10 to take heat from the coil end 10 for cooling.

[0045] On the other hand, a part of the cooling fluid C supplied to the header portion 16 is supplied from the outflow hole 19 provided in the cylindrical portion 17a of the guide member 17 constituting the header portion 16 toward the coil end 10 on the inner peripheral side of the cylindrical portion 17a. As a result, each coil end 10 protruding to both sides in the axial direction of the stator 3 is cooled by the cooling fluid C.

[0046] The cooling fluid C supplied to each coil end 10 flows downward on the lower side of the motor 1 and then returns to a storage part such as an oil pan (not shown). Then, it is drawn again by the pump 18 and supplied to the header part 16 described above. Since the cooling fluid C is circulated in this way, it is preferable to provide a radiator (or cooler) in the middle of its circulation path to cool the cooling fluid C.

[0047] The above-mentioned cooling fluid C is, for example, oil and functions to shield the magnetic flux 12. However, the inflow port 11 and the cooling flow path 14 filled with the cooling fluid C are configured such that the area (or projected area) of the surface perpendicular to the orientation of the magnetic flux 12 is smaller than the area in the direction parallel to the orientation of the magnetic flux 12. Therefore, it is possible to suppress as much as possible the shielding or obstruction of the magnetic flux 12 caused by the provision of the inflow port 11 and the cooling flow path 14 while ensuring the flow cross-sectional area of the inflow port 11 and the cooling flow path 14. That is, in the above configuration, it is possible to avoid or suppress a decrease in the magnetic characteristics of the stator 3 or the performance of the motor 1.

[0048] In addition, the above-mentioned inflow port 11, the communication hole part 13, and the cooling flow path 14 can be formed by punching through-holes in the electromagnetic steel sheets constituting the stator yoke 9 and laminating the electromagnetic steel sheets so that these through-holes are aligned. The processing of punching through-holes and the laminating operation of the electromagnetic steel sheets are not particularly different from the manufacturing operations of conventional stators. Therefore, according to the embodiment of the present invention, it is possible to easily obtain a stator 3 or a motor 1 with excellent cooling effects. In other words, it is possible to obtain a motor 1 with excellent thermal characteristics at low cost.

[0049] In addition, the present invention is not limited to the above-described embodiments and can be appropriately modified and implemented within the range that produces the above-described actions / effects. For example, in addition to being configured as a hole part continuous in the radial direction of the stator yoke, the communication hole part in the present invention may be: a hole part extending from the inflow port 11 to the middle of the cooling flow path 14 is formed in a predetermined electromagnetic steel sheet, and a hole part reaching the cooling flow path 14 from this hole part is formed in another adjacent electromagnetic steel sheet, and the communication hole part is constituted by these two hole parts. In addition, the shape of the guide member 17 constituting the header part 16 can be set to an appropriate shape according to the shape inside the motor housing 6. Moreover, the steel sheet provided with the inflow port or the steel sheet provided with the communication hole part may be a sheet material other than the electromagnetic steel sheet.

Claims

1. A cooling structure for an electric motor is a cooling structure for an electric motor that cools a stator using a cooling fluid. In the stator, a slot that opens toward the inner peripheral side and is continuous in the axial direction is formed in a stator yoke formed by laminating annular steel plates, and a coil is held inside the slot and the coil ends protrude from both ends in the axial direction of the stator yoke. In the cooling structure of the electric motor, At one end in the axial direction of the stator yoke and at a position radially outside the coil end, an inlet for the cooling fluid is provided. At a position closer to the slot than to the outer peripheral surface of the stator yoke, a cooling flow path for the cooling fluid is formed from one end side in the axial direction of the stator yoke toward the other end side. One end of the cooling flow path communicates with the inlet of the stator yoke, and The other end of the cooling flow path opens on the other end side of the stator yoke.

2. The cooling structure for an electric motor according to claim 1, The opening shape of the cooling flow path is a shape in which the dimension measured in the circumferential direction of the stator yoke is smaller than the dimension measured in the radial direction of the stator yoke.

3. The cooling structure for an electric motor according to claim 1, The opening shape of the inlet is a shape in which the dimension measured in the radial direction of the stator yoke is smaller than the dimension measured in the circumferential direction of the stator yoke.

4. The cooling structure for an electric motor according to any one of claims 1 to 3, The cooling structure of the electric motor is provided with a header portion, which is an annular space that covers the inlet on one end side in the axial direction of the stator yoke and distributes and supplies the cooling fluid to each of the inlets. In the header portion, an outflow hole for supplying the cooling fluid to the coil end protruding from one end side in the axial direction of the stator yoke is formed.

5. The cooling structure for an electric motor according to any one of claims 1 to 3, The cooling structure of the electric motor includes a third steel plate sandwiched between a first steel plate provided with the inlet and a second steel plate formed with the cooling flow path. In the third steel plate, a communication hole portion that opens to both the inlet provided in the first steel plate and the cooling flow path provided in the second steel plate is formed. The inlet and the cooling flow path are communicated through the communication hole portion.

Images