JP2012005204A - Motor cooling structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively cool a portion required to be cooled of a coil made up of a plurality of winding parts provided in a stator core with cooling oil.SOLUTION: A motor cooling structure 10 cools a coil 20 which is made up of a plurality of winding parts 26 and is wound on an inner periphery of a stator core 18, and to which AC voltage is applied from the outside of a motor, by pouring cooling oil C to a coil end that protrudes from an end surface of the stator core 18 in an axial direction. The motor cooling structure 10 includes a cooling oil feed pipe 40 for taking the cooling oil C from a cooling oil reservoir 42 and feeding the cooling oil C to the coil ends. The cooling oil feed pipe 40 includes an outlet for discharging the cooling oil C toward the coil ends. The outlet is formed in a direction allowing discharge of the cooling oil C to a clearance at a first winding part at which the difference in apportioned voltages born by winding parts is largest among a plurality of winding parts arranged adjacent to each other in a circumferential direction, and to a clearance at a second winding part at which the difference of the apportioned voltages is second largest.

Description

  The present invention relates to a motor cooling structure, and more particularly, to a motor cooling structure for cooling a coil wound around a stator core.

  Conventionally, it is known to cool a coil provided in a stator of a motor with cooling oil.

  For example, Japanese Patent Laid-Open No. 2008-35582 (Patent Document 1) discloses a stator core including teeth arranged in a ring, a coil provided on the stator core and supplied with AC power from an inverter, and a part of the coil as oil. The coil includes a plurality of winding portions wound around the teeth at positions shifted in the circumferential direction in which the teeth are arranged, and the shared voltage is the highest among the adjacent winding portions. There is disclosed a rotating electrical machine in which a coil is immersed in oil so as to immerse a space between a first winding portion and a second winding portion that become higher. In this rotating electrical machine, it is described that the oil level of the cooling oil is set at a position lower than that of the rotor so that the cooling oil is not agitated by the rotor driven to rotate in the stator.

  Japanese Patent Laying-Open No. 2009-71972 (Patent Document 2) discloses a cooling structure for a rotating electrical machine. The rotating electrical machine cooling structure includes a plurality of winding coils, and the rotating electrical machine can change the output depending on whether all sets of winding coils are energized or only a selected set of winding coils is energized. A cooling capacity adjusting means capable of individually adjusting a cooling capacity for each set of winding coils is provided, and the cooling capacity adjusting means is used to change the cooling capacity for the selected set of energized winding coils to a non-energized winding. It is characterized by being configured to be larger than the cooling capacity for the coil. More specifically, a plurality of refrigerant passages corresponding to the plurality of winding coils are formed so as to penetrate in the axial direction in the outer peripheral portion (that is, the yoke portion) of the stator core, and the refrigerant at a position corresponding to the energization winding coil The refrigerant passage is opened and closed so that the refrigerant flows only through the passage, and the cooling capacity for the winding coil is adjusted.

JP 2008-35582 A JP 2009-71972 A

  In the configuration described in Patent Document 1, a desired cooling region between the first winding portion and the second winding portion where the shared voltage is highest among the plurality of adjacent winding portions is at the lower portion of the stator core. The plurality of winding portions are arranged so as to be positioned, and the winding portions are cooled by immersing the desired cooling region in the cooling oil accumulated in the case housing the rotating electrical machine.

  However, depending on the posture in which the rotating electrical machine is installed, the desired cooling region between the first winding portion and the second winding portion where the shared voltage becomes the highest may not be disposed in the vertically downward position in the case. . For example, when the rotating electrical machine is mounted on, for example, an electric vehicle with the power input terminal of the rotating electrical machine facing the vertically upward position, the desired cooling region may be the vertically upward position. In this case, the desired cooling region cannot be immersed in the cooling oil accumulated on the oil level that is not stirred by the rotating rotor in the case, and it becomes difficult to cool the desired cooling region.

  Moreover, in the structure described in patent document 2, since the several coil wound around the teeth of the stator core is cooled with the refrigerant | coolant which flows through the inside of the refrigerant | coolant flow path which penetrates a stator core to an axial direction, heat capacity is Cooling through a large stator core cannot effectively cool the desired position of the plurality of winding coils.

  The object of the present invention is to effectively cool the above portion with cooling oil even when a portion of the coil composed of a plurality of winding portions provided in the stator core that is highly required to be cooled is disposed in the vertically upward position. An object of the present invention is to provide a motor cooling structure that can be used.

  The motor cooling structure according to the present invention includes a coil end that protrudes from an axial end surface of the stator core with respect to a coil that includes a plurality of winding portions wound around the inner periphery of the stator core and to which an AC voltage is applied from the outside of the motor. A cooling structure for cooling the motor by applying cooling oil to the part, including cooling oil feeding means that draws the cooling oil from the cooling oil reservoir and feeds the cooling oil toward the coil end part, the cooling oil feeding means Has a discharge port that discharges cooling oil toward the coil end portion, and the discharge port is a difference in shared voltage shared by each winding portion among the plurality of winding portions adjacent in the circumferential direction. Is formed in such a direction that the cooling oil is discharged at at least one of the position between the first winding portions where the current becomes the largest and the position between the second winding portions where the next becomes the largest.

  In the motor cooling structure according to the present invention, the cooling oil feeding means includes a cooling oil feeding pipe disposed above the stator core in a case housing the motor, and the peripheral wall of the cooling oil feeding pipe The first discharge port and the second discharge port may be formed in the portion so that the cooling oil is discharged toward the position between the first winding portions and the position between the second winding portions. .

  Further, in the motor cooling structure according to the present invention, the cooling oil supply means includes a cooling oil supply pipe disposed above the stator core in a case housing the motor and having the discharge port formed in the peripheral wall portion. And a portion of the cooling oil supply pipe where the discharge port is formed may be provided so as to be rotated around a central axis of the pipe.

  Further, in the motor cooling structure according to the present invention, the cooling oil feeding means includes a cooling oil feeding pipe extending in an axial direction above the stator core, and a peripheral wall portion of the cooling oil feeding pipe The discharge ports may be formed corresponding to coil end portions on both sides of the stator core with respect to the axial direction.

  In this case, the cooling oil supply pipe may be formed with another discharge port for discharging and applying the cooling oil to the outer peripheral surface of the stator core.

  Further, in the motor cooling structure according to the present invention, the coil is configured by connecting a plurality of winding portions in series, the winding portion closest to the input end of the AC power to the coil and the farthest winding portion. The space between the winding portions corresponds to the position between the first winding portions, and the space between the winding portion closest to the input end and the next winding portion is between the second winding portions. It may correspond to a position.

  In this case, when applied to a three-phase AC motor in which three sets of the coils are provided according to the three phases of the U phase, the V phase, and the W phase, and one end portions of each coil are connected to each other, The cooling oil may be discharged toward the position between the first winding portions and the position between the second winding portions for a set of coils that are assumed to have the largest amount of heat generation.

  Furthermore, in this case, each of the three sets of coils is configured by connecting a first winding group and a second winding group in which a plurality of winding portions are connected in series to each other in parallel. The cooling oil may be discharged toward the position between the first winding part and the position between the second winding part for each of the winding group and the second winding group.

  According to the motor cooling structure of the present invention, the discharge port that discharges the cooling oil toward the coil end portion has a difference in the shared voltage shared by each winding portion among the plurality of winding portions adjacent in the circumferential direction. Since it is formed in the direction in which the cooling oil is discharged in at least one position of the position between the first winding parts that becomes the largest and the position between the second winding parts that becomes the next largest, Even if the position between the first winding parts and the position between the second winding parts are positioned vertically upward or the like, the position between the first winding parts and the second winding which are likely to cause discharge between the windings. The cooling oil can be discharged directly and effectively by aiming at the position between the parts, and as a result, the pressure resistance performance of the coil that decreases as the temperature rises can be improved.

It is a schematic block diagram of the motor to which the motor cooling structure which is one Embodiment of this invention is applied. It is a figure which shows a mode that the cooling oil discharged from a cooling oil supply pipe is discharged toward a coil end part etc., (a) shows the case where the attachment position of a cooling oil supply pipe is constant, ( b) shows an example in which the mounting position of the cooling oil feed pipe can be adjusted. It is a figure which shows roughly the discharge position of the cooling oil with respect to the coil which consists of a some coil | winding part. It is a graph which shows the voltage sharing rate of each coil | winding part in the coil shown in FIG. It is a figure which shows a mode that cooling oil is discharged from the diagonal horizontal direction with respect to the coil which consists of a some winding part. It is a figure which shows the motor cooling structure which provided the heat radiator for temperature-falling cooling oil. It is a figure which shows roughly the coil structure and cooling position of a three-phase AC motor in which three sets of coils comprising a plurality of winding portions are provided for the U phase, V phase, and W phase. A three-phase AC motor in which three sets of coils composed of a plurality of winding portions are provided for the U-phase, V-phase, and W-phase, and each phase coil has a first winding group and a second winding group, respectively. It is a figure which shows roughly the coil structure comprised by connecting in parallel and a cooling position.

  Embodiments according to the present invention will be described below in detail with reference to the accompanying drawings. In this description, specific shapes, materials, numerical values, directions, and the like are examples for facilitating the understanding of the present invention, and can be appropriately changed according to the application, purpose, specification, and the like.

  In the following description, a direction along the rotor rotation center axis X of the motor is referred to as an “axial direction”, and a direction along a circle drawn around a point on the rotor rotation center axis X is referred to as a “circumferential direction”. The direction along the radius and diameter of the circle is called “radial direction”. Further, the motor has at least one of a function as an electric motor in which the rotor is rotationally driven by receiving electric power and a function as a generator that generates electric power when power is input to the rotor from the outside.

  FIG. 1 is a diagram schematically showing a motor 12 to which a motor cooling structure 10 of the present embodiment is applied. First, the configuration of the motor 12 will be described, and then the motor cooling structure 10 will be described in detail.

  The motor 12 includes a cylindrical stator 14 and a rotor 16 provided inside the stator 14. The motor 12 is accommodated in a case 13 having a substantially octagonal cross-sectional shape.

  The stator 14 includes a stator core 18 and a coil 20 provided on the inner periphery of the stator core 18. The stator core 18 is formed by, for example, laminating a large number of electromagnetic steel plates punched and punched in an annular shape and integrally connecting them by caulking or the like. However, the stator core 18 is not limited to one formed by laminating electromagnetic steel plates, and may be formed by a dust core divided into a plurality of pieces in the circumferential direction.

  The stator core 18 has an annular yoke 22 in a side view, and a plurality (eight in the present embodiment) of teeth that protrude radially inward from the inner peripheral surface of the yoke 22 and that are arranged at predetermined intervals in the radial direction. 24. Slots 28 are formed between the teeth 24. The slot 28 forms a groove-like space extending in the axial direction.

  Winding portions 26 are wound around the teeth 24, respectively. The winding part 26 is formed, for example, by winding a copper wire with an insulation coating. The conductive wire such as a copper wire forming the winding portion 26 may be a round cross-section electric wire, or may be a strip-like electric wire having a flat rectangular shape.

  As shown in FIG. 3, the coil 20 is formed by being connected in series by winding portions 26 adjacent in the circumferential direction. One end of the coil 20 is electrically connected to a positive electrode terminal 30 that is an input end of AC power. On the other hand, the other end of the coil 20 is electrically connected to a negative electrode terminal 32 which is an output end of AC power. An AC power source or an inverter (not shown) is connected to the positive electrode terminal 30 and the negative electrode terminal 32 so that AC power is supplied to the coil 20.

  Further, the winding portions 26 are adjacent to each other with a predetermined gap 27 in the circumferential direction. The size of the gap 27 is set so as to have an insulation resistance that does not cause a discharge between the winding portions 26 when an AC voltage is applied to the coil 20. The gap 27 may be formed as a space. However, the insulating performance of the stator 14 is improved by filling the gap 27 with an insulating mold resin to increase the insulation resistance and increase the discharge start potential difference. May be.

  In the following, for each of the eight winding portions 26 constituting the coil 20, the first winding portion 26a, the second winding portion 26b, and the third winding portion 26c, in order from the winding portion closer to the positive electrode terminal 30. The fourth winding portion 26d, the fifth winding portion 26e, the sixth winding portion 26f, the seventh winding portion 26g, and the eighth winding portion 26h. Similarly, with respect to the gap 27 between the winding portions 26, the first gap 27a, the second gap 27b, the third gap 27c, the fourth gap 27d, and the fifth gap are sequentially arranged from the winding portion closer to the positive electrode terminal 30. They are referred to as a gap 27e, a sixth gap 27f, a seventh gap 27g, and an eighth gap 27h.

  Referring again to FIG. 1, the rotor 16 includes a rotor core 34 that forms a cylindrical body, and a rotor shaft 36 that is made of, for example, a round steel bar and is fixed through the axial center of the rotor core 34. The rotor core 34 is formed by laminating a number of disc-shaped punched electromagnetic steel plates and integrally connecting them by caulking or the like.

  In the vicinity of the outer peripheral surface of the rotor core 34, a plurality of permanent magnets (not shown) are embedded at predetermined intervals in the circumferential direction. Further, both end portions of the rotor shaft 36 are supported by a bearing member provided on the side wall of the case 13 so as to be rotatable around the rotor rotation center axis X. At least one end of the rotor shaft 36 extends outside the case 13 so that power can be output from the motor 12 to the outside.

  In the motor 12 configured as described above, a rotating magnetic field is formed inside the stator 14 when AC power is supplied to the coil 20 from the outside of the motor. The rotor having a permanent magnet is driven to rotate by being attracted to the rotating magnetic field. Thereby, the rotational power by the motor 12 is output via the rotor shaft 36. When this motor 12 is mounted on an electric vehicle, for example, the power of the motor 12 is used to drive the vehicle.

  Next, the motor cooling structure 10 of this embodiment will be described in detail. The motor cooling structure 10 includes a cooling oil supply pipe 40. One end portion or lower end portion 41L of the cooling oil supply pipe 40 penetrates the wall portion of the case 13 in a liquid-tight state and extends into the case, and in the cooling oil reservoir portion 42 constituted by the bottom portion of the case 13 It is open. The height of the oil surface 44 of the cooling oil C accumulated in the cooling oil reservoir 42 is set such that the rotor 16 is not immersed when the motor 12 is installed so that the rotor rotation center axis X is in the horizontal direction. ing. Thereby, when the rotor 16 is rotationally driven, the cooling oil C is not stirred, and the accumulated cooling oil C can be prevented from becoming rotational resistance of the rotor 16.

  In the above description, the cooling oil reservoir 42 is described as being formed at the bottom of the case 13 housing the motor 12, but the invention is not limited to this, and the cooling oil reservoir is provided separately from the motor case. Also good.

  A pump 46 is provided in the middle of the cooling oil supply pipe 40. By driving the pump 46, the cooling oil accumulated in the case 13 is drawn from the lower end portion 41 </ b> L of the cooling oil supply pipe 40 and is pumped to the downstream side of the pump 46.

  The other end portion or upper end portion 41U of the cooling oil supply pipe located on the downstream side of the pump 46 penetrates the wall portion of the case 13 in a liquid-tight state, and is provided at a position vertically above the motor 12 in the case 13. It has been. The upper end portion 41U of the cooling oil feed pipe 40 is a cooling oil discharge pipe 48 that extends along the axial direction above the stator 14.

  As shown in FIG. 2A, the cooling oil discharge pipe 48 is disposed to face the cylindrical outer peripheral surface 19a of the stator core 18 with a gap. Coil end portions 21, which are axial end portions of the coils 20, protrude from the outer side of the axial end surface 19 b of the stator core 18. In the coil end portion 21, the winding portions 26 constituting the coil 20 are arranged in an annular shape with a gap 27 interposed therebetween. The length of the cooling oil discharge pipe 48 is set such that both end portions in the axial direction are located above the coil end portion 21. In FIG. 2A, the upper end portion 41U of the cooling oil supply pipe 40 is connected to the cooling oil discharge pipe 48 in a direction perpendicular to the paper surface.

  A discharge port 50 for discharging and applying the cooling oil C to the coil end portion 21 is formed in the lower peripheral wall portion of the cooling oil discharge pipe 48. The discharge ports 50 are respectively formed at both ends of the cooling oil discharge pipe 48 corresponding to the coil end portions 21 on both sides in the axial direction.

  In addition, the discharge port 50 becomes the next largest position between the first winding portions where the difference in the shared voltage shared by the winding portions 26a to 26h among the plurality of winding portions 26 adjacent in the circumferential direction is the largest. The cooling oil C is formed so as to be discharged at a position between the second winding portions. This will be described more specifically with reference to FIGS.

  3 is a diagram schematically showing the discharge position of the cooling oil C to the coil 20 composed of a plurality of winding portions 26a to 26h, and FIG. 4 is a voltage sharing of the winding portions 26a to 26h in the coil 20 shown in FIG. It is a graph which shows a rate. As shown in FIG. 4, in the coil 20 of the stator 14 of the motor 12, when an AC voltage is applied between the positive electrode terminal 30 and the negative electrode terminal 32 from the outside of the motor, the ratio of the voltage shared by the winding portions 26a to 26h, That is, the voltage sharing ratio is greatest at the first winding portion 26 a closest to the positive electrode terminal 30 and is next highest at the second winding portion 26 b second closest to the positive electrode terminal 30. In this case, since the difference r2 in the voltage sharing ratio between the first winding part 26a and the second winding part 26b becomes considerably large, the sharing between the first winding part 26a and the second winding part 26b accordingly. The voltage difference also increases.

  The voltage sharing ratio from the third winding portion 26 c to the eighth winding portion 26 h gradually decreases or becomes substantially the same as the distance from the positive terminal 30 increases. Therefore, the difference in the shared voltage shared by the winding parts 26b to 26h from the second winding part 26b to the eighth winding part 26h is considerably smaller than the difference in the shared voltage.

  On the other hand, as shown in FIG. 3, the first winding portion 26a and the eighth winding portion 26h are arranged adjacent to each other in the circumferential direction with the eighth gap 27 interposed therebetween, and the difference in voltage sharing ratio between them is r1 is larger than that between the first and second winding portions. Therefore, the difference in the shared voltage between the first winding portion 26 a closest to the positive electrode terminal 30 and the eighth winding portion 26 h farthest from the positive electrode terminal 30 is maximized in the coil 20.

  Thus, in the coil 20 of the stator 14 of the motor 12, the position between the first winding portions between the first winding portion 26a and the eighth winding portion 26h, that is, the eighth gap 27h, and the first winding portion 26a. Between the second winding portion 26b and the second winding portion 26b, that is, the first gap 27a, the difference in the shared voltage is the largest or the next largest, corresponding to the positions between the other winding portions. In the second gap 27b to the seventh gap 27g, the difference in the shared voltage is relatively small. Therefore, although it depends on the voltage value of the AC voltage applied to the motor 12 and the magnitude of the surge voltage, it can be said that the eighth gap 27h and the first gap 27a are areas where the inter-winding discharge is most likely to occur. On the other hand, the withstand voltage (that is, the discharge start voltage) of the electric wire constituting the winding portion 26 included in the coil 20 has a characteristic that it decreases as the temperature increases.

  Therefore, in the cooling oil discharge pipe 48 of the motor cooling structure 10 of the present embodiment, the first discharge port 50a that discharges or jets the cooling oil C toward the eighth gap 27h in the coil end portion 21 and the coil end portion 21. A second discharge port 50b that discharges or jets the cooling oil C toward the first gap 27a is formed. Both ends (left and right ends in FIG. 2A) of the cooling oil discharge pipe 48 are closed.

  In the example shown in FIG. 3, the first winding portion 26 a is provided at the uppermost position among the winding portions 26 that are evenly arranged in the circumferential direction, and the eighth gap 27 h and the both sides in the circumferential direction of the first winding portion and The first gap 27a is located. And since the cooling oil discharge pipe 48 is arrange | positioned in the center upper direction of the 1st coil | winding part 26a, the 1st and 2nd discharge ports 50a and 50b are with respect to the vertical direction line which passes along the center of the cooling oil discharge pipe 48. It is formed at a left-right symmetric position that is obliquely downward at a predetermined angle. However, the first and second discharge ports 50a and 50b do not necessarily have to be formed at symmetrical positions with respect to the vertical direction line, and the cooling oil C is supplied from the cooling oil discharge pipe 48 to the eighth gap 27h and the second gap. What is necessary is just to be formed so that it may discharge toward 1 clearance gap 27a.

  Further, as shown in FIG. 2A, the cooling oil discharge pipe 48 further has a stator core discharge port 51 for cooling the stator core 18. The stator core discharge port 51 faces the central position of the outer peripheral surface of the stator core 18 in the axial direction. Thereby, the cooling oil C discharged from the discharge port 51 flows downward on the outer peripheral surface of the stator core 18, and the stator core 18 is cooled. As a result, iron loss inside the stator core 18 can be suppressed, and energy efficiency can be improved. Note that the number of stator core discharge ports is not limited to one, and a plurality of stator core discharge ports may be formed at predetermined intervals in the axial direction.

  The cooling oil C discharged from the first discharge port 50a of the cooling oil discharge pipe 48 toward the eighth gap 27h is directly and effectively applied to both the first winding portion 26a and the eighth winding portion 26h. Can be cooled to. In addition, the cooling oil C discharged from the second discharge port 50b of the cooling oil discharge pipe 48 toward the first gap 27a is directly applied to both the first winding portion 26a and the second winding portion 26b. It can be cooled effectively.

  Thereafter, the cooling oil C flows down to the other winding portions 26c to 26 arranged in a ring shape through the gap 27 in the coil end portion 21 due to the weight effect, and falls between the other winding portions and the like in the meantime. Winding parts 26c-26 are also cooled. If the fifth winding portion 26e and the like at the lowest position in the case 13 is immersed in the cooling oil C accumulated in the cooling oil reservoir portion 42, the fifth winding portion 26e and the like are cooled by this. Will be. However, it is not essential that the lower portion of the stator 14 is immersed in the cooling oil C, and it is sufficient that the cooling oil C has accumulated to such an extent that it can be drawn in by the cooling oil feed pipe 40.

  The sizes and shapes of the discharge ports 50a and 50b are such that the coil end portion 21 is added to the first winding portion 26a, the second winding portion 26b, and the eighth winding portion 26h to which the cooling oil C is directly applied. Therefore, the amount of oil that can ensure adequate cooling performance for all the winding portions 26a to 26g, including the other winding portions 26c to 26g that are cooled in contact with the cooling oil C that flows down from above. It is designed suitably.

  Further, the amount of the cooling oil C discharged from the discharge ports 50a and 50b may be adjusted by controlling the operation of the pump 46. For example, when the voltage value of the AC voltage applied to the coil 20 is relatively high, the amount of heat generated in the coil 20 increases, so that the number of revolutions of the pump 46 is increased to increase the discharge amount of the cooling oil C. When the voltage value of the AC voltage applied to the coil 20 is relatively low, the amount of heat generated in the coil 20 becomes small, so the number of revolutions of the pump 46 may be increased to reduce the discharge amount of the cooling oil C. .

  Further, as shown in FIG. 2B, the cooling oil discharge pipe 48 constituting the upper end portion of the cooling oil supply pipe 40 may be provided so as to be rotated around the pipe central axis. Specifically, the upstream end portion of the cooling oil discharge pipe 48 is connected to the cooling oil supply pipe 40 via the joint portion 52, and the cooling oil discharge pipe 48 is connected to the joint portion 52 in the direction of the arrow 54. It can be rotated to adjust the mounting position. In this way, when an error occurs in the direction of the discharge ports 50a, 50b due to processing, assembly, etc., the discharge ports 50a, 50b are discharged by adjusting the mounting rotation position of the cooling oil discharge pipe 48. The cooling oil C can be accurately discharged toward the eighth gap 27h and the first gap 27a.

  As described above, according to the motor cooling structure 10 of the present embodiment, the discharge ports 50 a and 50 b that discharge the cooling oil C toward the coil end portion 21 are among the plurality of winding portions 26 that are adjacent in the circumferential direction. It is formed in such a direction that the cooling oil C is discharged to the first inter-winding portion position 27h where the difference in the shared voltage shared by the respective winding portions 26a to 26h becomes the largest and the second inter-winding portion position 27a that becomes the next largest. Therefore, even if the first interwinding portion position 27h and the second interwinding portion position 27a are located vertically upward in the case 13, the first winding portion is likely to cause discharge between the winding portions. The cooling oil C can be discharged directly and effectively by aiming at the intermediate position 27h and the second interwinding portion position 27a, and as a result, the coil 20 that decreases as the temperature rises. Improve pressure resistance performance It is possible. Thereby, functions and characteristics such as the output, energy efficiency, and thermal characteristics of the motor that have been sacrificed for ensuring the insulation of the coil 20 can be improved.

  In the above, the cooling oil is directed toward the position between the first winding parts where the difference in the shared voltage between the winding parts becomes the maximum and the position between the second winding parts where the difference in the shared voltage becomes the next largest. Although described as discharging, the cooling oil is discharged from one cooling oil discharge pipe to both positions because the position between the first winding parts and the position between the second winding parts are separated in the circumferential direction. If this is not possible, one discharge port for discharging the cooling oil may be formed at one of the first interwinding portion position and the second interwinding portion position. In this case, the cooling oil discharge pipe is bifurcated into two cooling oil discharge pipes corresponding to the positions between the first winding portions and the positions between the second winding portions, and 1 formed on each cooling oil discharge pipe. The cooling oil may be discharged from one discharge port toward the position between the first winding portions and the position between the second winding portions.

  In addition, three or more discharge ports may be formed at one end of the cooling oil discharge port as necessary.

  Next, a modified example of the motor cooling structure 10 will be described with reference to FIG. The coil 20 of the stator 14 of the motor 12 is the same as the above in that the first to eighth winding portions 26 a to 26 h are connected in series, but the first winding portion connected to the positive terminal 30. The difference is that the eighth winding part 26h connected to 26a and the negative terminal 32 is arranged not in the vertical direction but in the lateral or lateral direction (right side in FIG. 5). Such a posture of the coil 20 may be employed when, for example, the positive electrode terminal 30 and the negative electrode terminal 32 are pulled out in the horizontal direction.

  In this case, the mounting position of the cooling oil discharge pipe 48 is also different from the above in accordance with the posture of the coil 20. That is, in the example shown in FIG. 5, the cooling oil discharge pipe 48 is disposed on the side of the coil 20 so as to face the first winding part 26a, and the eighth oil pipes on both sides in the circumferential direction of the first winding part 26a. The cooling oil C is discharged or ejected from the first discharge port 50a and the second discharge port 50b toward the gap 27h and the first gap 27a. Other configurations are the same as those of the motor cooling structure 10.

  This modification can also provide the same effects as described above. However, in this case, sufficient cooling performance is ensured also for the third winding portion 26c positioned vertically above and the third to sixth winding portions 26c to 26f positioned away from the cooling oil discharge pipe 48. Therefore, it is preferable to increase the oil amount and / or the ejection pressure of the cooling oil C ejected from the second discharge port 50b toward the first gap 27a.

  Next, another modification of the motor cooling structure 10 will be described with reference to FIG. As shown in FIG. 6, the cooling oil supply pipe 40 is provided with a radiator 56 on the downstream side of the pump 46. When passing through the heat radiator 56, the cooling oil C releases the heat obtained by cooling the coil 20 and the like to the outside and lowers the temperature. Any known structure may be used for the radiator 56. Thus, by providing the radiator 56 and lowering the temperature of the cooling oil C, the coil 20 and the like can be cooled more effectively.

  Next, an example in which the motor cooling structure 10 is applied to a three-phase AC motor will be described with reference to FIGS. FIG. 7 is a diagram schematically showing a coil configuration and a cooling position of a three-phase AC motor in which three sets of coils including a plurality of winding portions are provided for the U phase, the V phase, and the W phase.

  A three-phase AC motor generally includes three sets of coils 20U, 20V, and 20W corresponding to the U phase, the V phase, and the W phase. One end portions of the three-phase coils 20U, 20V, and 20W are connected to power input terminals 30U, 30V, and 30W corresponding to the respective phases. On the other hand, the other ends of the three-phase coils 20U, 20V, and 20W are electrically connected to each other at a neutral point 31. This neutral point 31 corresponds to the power output terminal of each phase coil 20U, 20V, 20W.

  Each of the phase coils 20U, 20V, and 20W is configured, for example, by connecting eight winding portions in series. Speaking of the U-phase coil 20U, of the eight winding portions 26Ua to 26Uh, the winding portion 26Ua closest to the power input terminal 30U and the farthest from the power input terminal 30 (that is, the most at the neutral point 31). The closer winding portion 26Uh corresponds to the position between the first winding portions, and the gap between the winding portion 26Ua closest to the power input terminal 30U and the next winding portion 26Ub is the first. This corresponds to the position between the two winding parts.

  The same applies to the V-phase coil 20V and the W-phase coil 20W. That is, in the V-phase coil 20V, the position between the winding portion 26Va closest to the power input terminal 30V and the furthest winding portion 26Vh among the eight winding portions 26Va to 26Vh corresponds to the position between the first winding portions. A position between the winding portion 26Va closest to the power input terminal 30V and the next winding portion 26Vb corresponds to the position between the second winding portions. Regarding the W-phase coil 20W, the position between the winding portion 26Wa closest to the power input terminal 30W and the furthest winding portion 26Wh among the eight winding portions 26Wa to 26Wh corresponds to the position between the first winding portions. The portion between the winding portion 26W nearest to the power input terminal 30W and the next winding portion 26Wb corresponds to the position between the second winding portions.

  The cooling oil discharge pipe 48 of the motor cooling structure 10 includes a position between the first winding portion and a position between the second winding portion of the one-phase coil that is assumed to generate the largest amount of heat among the three-phase coils 20W, 20V, and 20W. It arrange | positions in the position which discharges cooling oil toward a position. Which phase of coil 20U, 20V, 20W maximizes the amount of heat generation can be specified in advance by conducting an actual machine experiment in which the motor 12 is mounted on an electric vehicle or the like together with a battery or a power conversion circuit. .

  Here, when the three-phase AC motor is mounted on an electric vehicle, the current of the three-phase coils 20U, 20V, and 20W flows depending on the flow of the common current flowing back to the power conversion circuit via the motor stator and the vehicle body. Variations in flow and heat generation may occur. Therefore, it is effective to directly cool with the cooling oil discharged from the cooling oil discharge pipe, giving priority to the one-phase coil that generates the largest amount of heat and the highest necessity for insulation confirmation as described above. is there.

  However, even if it does in this way, since the other phase coil is also cooled in the position between 1st and 2nd coil | winding parts with the cooling oil which flows through the coil end part 21 which makes | forms a substantially annular shape, there is no problem. For example, even if the cooling oil discharge pipe 48 is arranged corresponding to the U-phase coil 20U, the position between the first and second winding portions in the other V-phase and W-phase coils 20V and 20W is U If the three-phase coil is wound around the stator core so as to be positioned close to those of the phase coil 20 in the circumferential direction, discharge is made from the first and second discharge ports 50a and 50b formed in the cooling oil discharge pipe 48. When the cooling oil to be applied is applied almost directly, effective cooling can be performed simultaneously on the positions between the first and second winding portions of the coils of two or more phases.

  When the motor cooling structure 10 is applied to a three-phase AC motor in this way, the cooling oil discharge pipe 48 is disposed corresponding to the coil of one phase that is supposed to generate the largest amount of heat, and the first and second By discharging the cooling oil C from the discharge ports 50a and 50b toward the position between the first and second winding portions, it is possible to improve the pressure resistance performance of the three-phase coil, in particular, the coil in which interwinding discharge is likely to occur. Can do. As a result, it is possible to improve functions and characteristics such as the output, energy efficiency, and thermal characteristics of the motor that have been sacrificed to ensure the insulation of the coil.

  In the three-phase AC motor, when the positions between the first and second winding portions of at least two-phase coils are located close to each other in the circumferential direction, two, three, By applying cooling oil discharged or ejected from one or four discharge ports toward the desired cooling position of the two-phase coil, a plurality of coils can be effectively cooled simultaneously. In addition, when the position between the first and second winding portions of each phase coil is located apart in the circumferential direction, a plurality of cooling oil discharge pipes branched from the cooling oil supply pipe are provided to each phase coil. You may arrange | position facing the desired cooling position.

  Next, an example in which the motor cooling structure 10 is applied to another three-phase AC motor will be described with reference to FIG. Here, only differences from the three-phase AC motor described above with reference to FIG. 7 will be described, and the same or similar components will be denoted by the same or similar reference numerals and redundant description will be omitted with the aid of the description.

  As shown in FIG. 8, the three-phase AC motor includes three sets of coils 20U, 20V, and 20W corresponding to the U phase, the V phase, and the W phase. Each phase coil 20U, 20V, and 20W is configured by connecting a first winding portion group and a second winding portion group, in which a plurality of winding portions are connected in series, in parallel.

  Specifically, first, the U-phase coil 20U will be described. In the U-phase coil 20U, a first winding part group in which four winding parts 26Ua to 26Ud are connected in series and four winding parts 26Ue to 26Uh are provided. A second winding section group connected in series is connected in parallel. For the first winding portion group, the position between the winding portion 26Ua closest to the power input terminal 30U and the winding portion 26Ud farthest from the power input terminal 30U is the position between the first winding portions. The portion between the winding portion 26Ua closest to the power input terminal 30U and the next winding portion 26Ub closest to the power input terminal 30U corresponds to the position between the second winding portions. For the second winding portion group, the position between the first winding portion is between the winding portion 26Ue closest to the power input terminal 30U and the winding portion 26Uh farthest from the power input terminal 30U. The portion between the winding portion 26Ue closest to the power input terminal 30U and the next winding portion 26Uf closest to the power input terminal 30U corresponds to the position between the second winding portions.

  The positions between the first and second winding portions in the other-phase coils 20V and 20W are the same as those in the U-phase coil 20U described above.

  In the three-phase coils 20U, 20V, and 20W including the first and second winding part groups, for example, when the U-phase coil 20U is assumed to generate the largest amount of heat, the cooling oil discharge pipe 48 is connected to the U By providing cooling oil discharged from at least two discharge ports 50a and 50b toward the position between the first and second winding portions of the first and second winding groups provided corresponding to the phase coil 20U In addition, it is possible to directly and effectively cool the coil portion where the interwinding portion discharge is likely to occur. As a result, it is possible to improve the pressure resistance performance of the three-phase coil, particularly the coil that is liable to cause inter-winding discharge. As a result, the motor output and energy efficiency that have been sacrificed to ensure the insulation of the coil. In addition, functions and characteristics such as thermal characteristics can be improved.

  Even in this case, if necessary, three or more discharge ports may be formed at one end of one cooling oil discharge pipe 48, or a plurality of cooling oil discharge pipes may be provided. .

  In the above description, the cooling oil C is discharged from the discharge ports 50a and 50b formed in the cooling oil discharge pipe 48 and applied to the desired cooling position of the coil end portion 21, but the motor cooling structure according to the present invention is used. The cooling oil feeding means is not limited to this, and various changes and improvements can be made.

  For example, a cooling oil passage that circulates the cooling oil is formed in a groove shape or a through-hole shape in the wall portion of the case housing the motor, and a discharge port that communicates with the cooling oil passage is opened in the wall portion of the case. May be formed.

  10 motor cooling structure, 12 motor, 13 case, 14 stator, 16 rotor, 18 stator core, 19a outer peripheral surface, 19b end surface, 20 coil, 20U U phase coil, 20V V phase coil, 20W W phase coil, 21 coil end portion, 22 yoke, 24 teeth, 26 winding part, 26a to 26h 1st to 8th winding part, 27 clearance, 27a to 27h 1st to 8th clearance, 28 slot, 30 positive terminal, 30U, 30V, 30W Terminal, 31 Neutral point, 32 Negative terminal, 34 Rotor core, 36 Rotor shaft, 40 Cooling oil feed pipe, 41L Lower end, 41U Upper end, 42 Cooling oil reservoir, 44 Oil level, 46 Pump, 48 Cooling oil Discharge pipe, 50, 50a, 50b Discharge port, 51 Stator core discharge port, 52 Joint part, 56 Radiator, C Cooling oil, X Rotor rotation center axis.

Claims (8)

A coil composed of a plurality of winding portions wound around the inner periphery of the stator core and applied with an AC voltage from the outside of the motor is cooled by applying cooling oil to the coil end portion protruding from the axial end surface of the stator core. A motor cooling structure,
Cooling oil feeding means that draws cooling oil from the cooling oil reservoir and feeds it toward the coil end part. The cooling oil feeding means has a discharge port that discharges cooling oil toward the coil end part. The discharge port has a position between the first winding portions where the difference in the shared voltage shared by each winding portion among the plurality of winding portions adjacent to each other in the circumferential direction is the largest and the next largest. The motor cooling structure formed in the direction in which the said cooling oil is discharged to at least one position of the position between 2nd coil | winding parts. The motor cooling structure according to claim 1,
The cooling oil feeding means includes a cooling oil feeding pipe disposed above the stator core in a case that accommodates a motor, and the first winding is disposed on a peripheral wall portion of the cooling oil feeding pipe. A motor cooling structure in which a first discharge port and a second discharge port are formed so that cooling oil is discharged toward a position between parts and a position between the second winding parts. The motor cooling structure according to claim 1 or 2,
The cooling oil feeding means includes a cooling oil feeding pipe disposed above the stator core in a case housing the motor and having the discharge port formed in a peripheral wall portion thereof. Of these, the motor cooling structure is characterized in that the portion where the discharge port is formed is provided so as to be able to be rotated around the central axis of the pipe. In the motor cooling structure according to any one of claims 1 to 3,
The cooling oil feeding means includes a cooling oil feeding pipe extending in the axial direction above the stator core, and the circumferential wall portion of the cooling oil feeding pipe is on both sides of the stator core with respect to the axial direction. A motor cooling structure in which the discharge port is formed corresponding to a coil end portion. The motor cooling structure according to claim 4,
The motor cooling structure according to claim 1, wherein the cooling oil supply pipe is formed with another discharge port for discharging and applying the cooling oil to the outer peripheral surface of the stator core. In the motor cooling structure according to any one of claims 1 to 5,
The coil is configured by connecting a plurality of winding portions in series, and the first winding is between the winding portion closest to the input end of the AC power to the coil and the winding portion farthest from the coil. Motor cooling, which corresponds to a position between the wire portions, and a portion between the winding portion closest to the input end and the winding portion closest to the next corresponds to the position between the second winding portions. Construction. The motor cooling structure according to claim 6,
When applied to a three-phase AC motor in which three sets of coils are provided according to the three phases of U phase, V phase and W phase, and one end of each coil is connected to each other, at least the most calorific value A motor cooling structure in which cooling oil is discharged toward a position between first winding portions and a position between second winding portions for a set of coils that are assumed to be large. The motor cooling structure according to claim 7,
Each of the three sets of coils is configured by connecting a first winding group and a second winding group, in which a plurality of winding portions are connected in series, in parallel. A motor cooling structure in which cooling oil is discharged toward a position between first winding portions and a position between second winding portions for each of two winding groups.

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