Rotary electric machine

Abstract

To provide a rotary electric machine in which cooling of a coil by a cooling liquid is maintained even when a rotor rotates at high speed.SOLUTION: The motor includes a stator S including a stator core 11 and a coil 12, and a rotor R rotating around a rotation axis X in an internal space of the stator core 11. The stator includes a first coolant flow path 12a that supplies the coolant Lc from the outside in the radial direction to the coil end portion C1 of the coil 12, and a second coolant flow path C2 that supplies the coolant Lc from the inside in the radial direction to the coil end portion inner wall of the coil 12. When the amount of the coolant Lc supplied from the second coolant flow path C2 to the coil end portion 12a is a first supplied amount when the rotational speed of the rotor R is a first set value, and the amount of the coolant Lc supplied from the second coolant flow path C2 to the coil end portion 12a is a second supplied amount when the rotational speed is a second set value that is larger than the first set value, the second supplied amount is smaller than the first supplied amount.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a rotating electric machine. [Background technology]

[0002] Patent document 1 describes a rotating electric machine in which a rotor that rotates integrally with a rotor shaft is arranged inside an annular stator core, and multiple coolant guides are formed on the end plate of the rotor to protrude outward.

[0003] This patent document 1 discloses a configuration in which a coolant inlet passage is formed from inside the rotor shaft to send coolant to multiple coolant guides, and as the rotor rotates, oil from the rotor shaft is supplied to the multiple coolant guides via the coolant inlet passage, and coolant is supplied from the coolant guides to the coil ends of the stator core coils by centrifugal force, thereby achieving cooling. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-129944 Summary of the Invention [Problem to be solved by the invention]

[0005] Taking an electric motor as an example of a rotating electrical machine, the coils of the stator core generate heat as power is supplied, and when this heat generation causes a temperature rise, the temperature rise can be suppressed by supplying a coolant.

[0006] Taking electric motors as an example, cooling methods have been considered in which coolant is dripped onto the coils from the outside of the stator without using centrifugal force, in which the coolant comes into contact with the coils due to its own weight.

[0007] Here, as disclosed in Patent Document 1, it is assumed that cooling is performed by supplying coolant to the coil ends by spraying using centrifugal force and also by dripping coolant to the coil ends.

[0008] In this assumed system where coolant is supplied to the coil ends using two different supply methods, the spray speed of the coolant supplied to the coil ends increases due to centrifugal force as the rotation speed of the electric motor increases. This causes the coolant supplied by centrifugal force to drip and blow away the coolant already supplied to the coil ends, raising concerns that this could actually reduce the cooling effect.

[0009] In particular, it has been confirmed that when the rotation speed exceeds 10,000 revolutions per minute (10,000 rpm), this phenomenon of cooling liquid being blown away is more likely to occur, and the cooling effect is more likely to decrease.

[0010] For these reasons, there is a demand for a rotating electrical machine that can maintain the cooling of the coils by the coolant even when the rotor rotates at high speeds. [Means for solving the problem]

[0011] A characteristic configuration of the rotating electric machine according to the present invention is a stator including a stator core arranged in a tubular region centered on a rotation axis and coils having coil end portions protruding axially outward from the stator core; a rotor arranged in an internal space of the stator core and rotating around the rotation axis; a first cooling flow path that supplies coolant to the coil end portions from the outside in a radial direction of the stator core; and a second cooling flow path that can supply the coolant to the coil end portions from the inside in the radial direction by centrifugal force associated with rotation of the rotor, wherein when the supply amount of the coolant supplied from the second cooling flow path to the coil end portions when the rotation speed per unit time of the rotor is at a first set value is defined as a first supply amount, and when the supply amount of the coolant supplied from the second cooling flow path to the coil end portions when the rotation speed is at a second set value that is greater than the first set value is defined as a second supply amount, the second supply amount is smaller than the first supply amount.

[0012] According to this configuration, when the rotor's rotation speed per unit time is a second set value greater than the first set value, a second supply amount of coolant, which is less than the first supply amount, is supplied to the coil end portion from the second cooling passage. In other words, with this configuration, coolant is continuously supplied to the coil end portion from the first cooling passage, and the amount of coolant supplied to the coil end portion by centrifugal force from the second cooling passage decreases as the rotor rotation speed increases. This prevents the coolant supplied by centrifugal force from the second cooling passage from blowing away the coolant already supplied from the first cooling passage. This configuration provides a rotating electric machine that maintains cooling of the coil by coolant even when the rotor rotates at high speeds. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram showing an outline of the configuration of a vehicle electric device. [Figure 2] 3 is a cross-sectional view of a vehicle electric device showing a cooling flow path and an ejection flow path. FIG. [Figure 3] FIG. 10 is a cross-sectional view showing a jetting flow path of another embodiment (a) formed at an inclination angle α1. [Figure 4] FIG. 10 is a cross-sectional view showing the jetting flow path of another embodiment (a) formed at an inclination angle α2. [Figure 5] FIG. 10 is a cross-sectional view showing the jetting flow path of another embodiment (a) formed at an inclination angle α3. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of a rotating electrical machine according to the present invention will be described with reference to the drawings. The present embodiment is not limited to the following embodiment, and various modifications are possible without departing from the spirit and scope of the present invention.

[0015] [Basic configuration] FIG. 1 shows a part of a vehicle drive device A that transmits the driving force of an electric motor M (an example of a rotating electric machine) to traveling wheels (not shown) in a vehicle such as a hybrid electric vehicle (HEV) or a battery electric vehicle (BEV).

[0016] The vehicle drive device A accommodates an electric motor M (rotating electric machine), a reduction gear G1, and a differential gear G2 in a housing 1 made of aluminum or the like. The vehicle drive device A reduces the rotation of a cylindrical shaft 15 (an example of a shaft) driven and rotated by the electric motor M using the reduction gear G1, and transmits the rotation to left and right drive shafts 16 via the differential gear G2, thereby enabling the vehicle to travel.

[0017] This vehicle drive device A is mounted on a vehicle in the position shown in Figures 1 and 2, and a pair of drive shafts 16 arranged coaxially with the rotation axis X transmit drive force to left and right running wheels (not shown), and the rotor R of the electric motor M rotates around the rotation axis X in a horizontal position.

[0018] In the following description, the configuration of the vehicle drive device A and the positional relationship of each part of the electric motor M will be described in accordance with the vertical relationship shown in FIG.

[0019] [Electric motor] As shown in FIGS. 1 and 2, an electric motor M (rotating electric machine) includes a stator S, a rotor R, a first cooling passage C1, and a second cooling passage C2.

[0020] The stator S includes a stator core 11 formed by laminating multiple electromagnetic steel plates into a tubular shape centered on the rotation axis X, and coils 12 having coil end portions 12a protruding from outer ends on both axial sides of the stator core 11. The coils 12 are fitted into multiple slots parallel to the rotation axis X in the inner peripheral portion of the stator core 11.

[0021] The outer periphery of the stator core 11 is supported in a state where a part of the outer periphery is in close contact with the inner periphery of the housing 1. In addition, a plurality of fins 1a for heat dissipation are formed on the outer surface of the region of the housing 1 where the stator core 11 is supported in close contact with the inner periphery (upper side in FIG. 2).

[0022] As a result, when a current is supplied to the coil 12 and the temperature of the coil 12 rises, the heat is dissipated from the fins 1a of the housing 1 via the stator core 11. Furthermore, when a current is supplied to the coil 12 and the temperature of the coil 12 rises, the coolant Lc flowing through the first cooling flow path C1 and the second cooling flow path C2 is supplied to the coil end portion 12a, thereby suppressing the temperature rise of the coil 12. The first cooling flow path C1 and the second cooling flow path C2 will be described in detail later.

[0023] The rotor R includes a cylindrical shaft 15, a rotor core 13 formed integrally with the outer periphery of the cylindrical shaft 15 by laminating a plurality of electromagnetic steel plates into a cylindrical shape as a whole, and a plurality of permanent magnets 14 embedded inside the rotor core 13. The rotor R is supported by the housing 1 so as to be rotatable about a rotation axis X.

[0024] The first cooling flow path C1 supplies the coolant Lc to the outer surfaces of the coil end portions 12a from the radially outer side above the stator core 11. The second cooling flow path C2 supplies the coolant Lc to the inner surfaces of the coil end portions 12a from the radially inner side of the stator core 11 by centrifugal force caused by the rotation of the rotor R.

[0025] In this embodiment, the coolant Lc is lubricating oil stored inside the vehicle drive device A. As shown in Fig. 1, the vehicle drive device A supplies the coolant Lc (lubricating oil) stored in the bottom of the housing 1 from an electric oil pump 2 to an oil cooler 3 through a cooling passage 4, and the coolant Lc cooled by the oil cooler 3 is supplied to a first cooling passage C1 and a second cooling passage C2.

[0026] The coolant Lc may be a fluid that has low viscosity and can be used as a lubricant, such as ATF (Automatic Transmission Fluid).

[0027] 1, the vehicle drive device A includes the oil cooler 3 and a power control circuit 6 that functions as a PCU (Power Control Unit) on the outer surface of the housing 1. In order to lower the temperature of the coolant Lc flowing through the oil cooler 3, the vehicle drive device A also includes, outside the housing 1, a pipe 8 through which the coolant Wc circulates, a radiator 7 that removes heat from the coolant Wc, and a circulation pump 9 that circulates the coolant Wc.

[0028] The cooling water Wc may be a long life coolant (LLC) containing ethylene glycol, propylene glycol, or the like.

[0029] As a result, the coolant Lc is supplied to the electric motor M, reduction gear G1, differential gear G2, etc., and then supplied to the oil cooler 3 by the oil pump 2 from the bottom of the housing 1. The coolant Lc circulates in such a manner that its heat is dissipated in the oil cooler 3 before being supplied to the inside of the housing 1. The coolant Wc, which has absorbed heat from the coolant Lc in the oil cooler 3 and from the power control circuit 6, dissipates heat in the radiator 7.

[0030] [Electric motor: first cooling channel] The oil pump 2 is driven at a set rotational speed regardless of the rotational speed (number of rotations per unit time / sometimes simply referred to as the number of rotations) of the electric motor M, and circulates a fixed amount of coolant Lc per unit time through the cooling flow path 4.

[0031] As shown in Figures 1 and 2, the first cooling flow path C1 has a pair of supply parts 21 arranged at positions sandwiching the stator core 11 in a direction along the rotation axis X, and a hole-shaped flow path 22 that sends the coolant Lc downward from the pair of supply parts 21.

[0032] The supply parts 21 have a storage space for temporarily storing the coolant Lc, and the flow paths 22 are connected to the storage space. Each supply part 21 is disposed above the coil end parts 12a that protrude from both outer end surfaces of the stator core 11 in the direction along the rotation axis X, and above the highest of the multiple coil end parts 12a.

[0033] The storage spaces of the pair of supply parts 21 are connected via an intermediate flow path 23 inside the housing 1. Therefore, by supplying the coolant Lc from the cooling flow path 4 to one of the pair of supply parts 21 (the right supply part 21 in FIGS. 1 and 2), the supplied coolant Lc is supplied to the other supply part 21 via the intermediate flow path 23.

[0034] Since the first cooling flow path C1 is configured in this manner, the cooling liquid Lc supplied from the cooling flow path 4 to the pair of supply sections 21 is supplied in a form that flows down from each of the flow-down flow paths 22 of the pair of supply sections 21 to the coil end section 12a, thereby realizing cooling of the coil end section 12a.

[0035] The stator core 11 has a plurality of coils 12 positioned adjacent to each other in the circumferential direction of the stator core 11, and coil end portions 12a are formed on these coils 12. As a result, the coolant Lc discharged from the flow passage 22 flows from the upper surfaces of the plurality of coil end portions 12a along the upper surfaces of the adjacent coil end portions 12a.

[0036] In this embodiment, the first cooling flow path C1 is provided as a single unit including a pair of supply portions 21 in the housing 1. However, as a modification, for example, the first cooling flow path C1 may be configured using multiple units, and the coolant Lc from the downstream flow paths 22 of each unit may be supplied to multiple coil end portions 12a.

[0037] [Electric motor: second cooling channel] As shown in Figure 2, the second cooling passage C2 has a shaft-side passage 25 between the outer surface of the drive shaft 16 and the inner surface of the tubular shaft 15, and a plurality of ejection passages 26 formed in the tubular shaft 15 so as to eject the cooling liquid Lc from this shaft-side passage 25 by centrifugal force.

[0038] The drive shaft 16 has a central passage 27 formed coaxially with the rotation axis X. The drive shaft 16 has a supply passage 27a that penetrates the drive shaft 16 in the radial direction so as to supply the coolant Lc in the central passage 27 to the shaft-side passage 25.

[0039] The drive shaft 16 also has a receiving passage 27b that penetrates the drive shaft 16 in the radial direction so as to supply the coolant Lc to the central passage 27. The housing 1 has a supply passage 28 that supplies a portion of the coolant Lc supplied to one supply part 21 to the receiving passage 27b.

[0040] As shown in Figures 1 and 2, the drive shaft 16 is formed with a plurality of lubrication passages 27c that penetrate radially so as to supply the cooling liquid Lc as lubricating oil to bearing parts such as the reduction gear G1, the differential gear G2, and the ball bearings.

[0041] [Electric motor: Ejection channel of second cooling channel] 2, the multiple ejection flow paths 26 are arranged at multiple locations in the circumferential direction of the cylindrical shaft 15, at two locations that sandwich the stator core 11 in the direction along the rotation axis X. By forming the multiple ejection flow paths 26 in this manner, it is possible to eject the coolant Lc onto the coil end portion 12a that is the injection target by the centrifugal force generated when the rotor R rotates.

[0042] The multiple ejection flow paths 26 are formed such that the center line P, through which the coolant Lc is discharged, is inclined at an inclination angle α about the rotation axis X. In particular, the inclination angle α of the ejection flow paths 26 is set so that the center line P passes axially outside the protruding ends of the coil end portions 12a.

[0043] For example, in a case where the ejection flow passage 26 is formed in an orientation perpendicular to the rotation axis X (the inclination angle α is 90 degrees), the speed of the coolant Lc when it contacts the coil end portion 12a increases as the number of rotations per unit time of the rotor R increases. In this way, it has been confirmed that when the accelerated coolant Lc contacts the coil end portion 12a, the coolant Lc blows away the coolant Lc that has already been supplied from the first cooling flow passage C1 to the coil end portion 12a, resulting in a decrease in cooling performance.

[0044] In terms of specific numerical values, when the electric motor M (rotor R) rotates at approximately 10,000 rpm, it has been confirmed that the phenomenon of blowing away the coolant Lc already supplied to the coil end portion 12a is observed, and when it rotates at approximately 17,000 rpm, the phenomenon of blowing away the coolant Lc already supplied becomes more pronounced.

[0045] For this reason, when the electric motor M exceeds a set rotation speed (approximately 10,000 rpm), in order to reduce the amount of coolant Lc ejected from the ejection flow path 26 that comes into contact with the coil end portion 12a, the ejection flow path 26 is inclined at an inclination angle α with respect to the rotation axis X so that the center line P faces axially outward beyond the outer end (protruding end) of the coil end portion 12a, as shown in FIG. 2.

[0046] In this way, in the second cooling flow path C2, the ejection flow path 26 is inclined at an inclination angle α. Therefore, when the coolant Lc is discharged from the ejection flow path 26 in accordance with the rotation of the rotor R, the coolant Lc is subjected to a centrifugal force acting to move it away from the rotation axis X and a pressure acting to cause the coolant Lc to flow along the center line P of the ejection flow path 26.

[0047] That is, as the rotational speed of the rotor R increases, although the centrifugal force increases in the coolant Lc sent out from the ejection channel 26, the pressure acting in the direction along the center line P increases, and as the flow velocity of the coolant Lc increases, the coolant Lc ejected from the ejection channel 26 has a higher tendency to move along the center line P.

[0048] When the rotational speed of the rotor R per unit time is less than the first set value Re1, since the centrifugal force is greater than the pressure acting on the coolant Lc along the center line P, most of the coolant Lc ejected from the ejection channel 26 is supplied inside the coil end portion 12a. Further, when the rotational speed of the electric motor M reaches the second set value Re2, most of the coolant Lc ejected from the ejection channel 26 moves along the center line P, and the amount of the coolant Lc contacting (supplied to) the coil end portion 12a significantly decreases.

[0049] Specifically, the second set value Re2 is about 10000 rpm, and the first set value Re1 is a value smaller than this (Re2 > Re1). Also, when the rotational speed of the rotor R per unit time is at the first set value Re1, the supply amount of the coolant Lc supplied from the second cooling channel C2 to the coil end portion 12a is taken as the first supply amount Q1, and when the rotational speed is the second set value Re2 greater than the first set value Re1, the supply amount of the coolant Lc supplied from the second cooling channel C2 to the coil end portion 12a is taken as the second supply amount Q2, and it is configured such that the second supply amount Q2 is less than the first supply amount Q1 (Q2 < Q1).

[0050] Furthermore, when the rotational speed of the rotor R per unit time is equal to or greater than a third set value Re3 greater than the second set value Re2, it is configured such that most of the coolant Lc is sent out along the center line P shown in FIG. 2. As a result, if the rotational speed of the rotor R per unit time is equal to or greater than the third set value Re3, the supply amount of the coolant Lc to the coil end portion 12a becomes substantially zero. Note that "becomes substantially zero" means a state in which most of the ejected coolant Lc is not supplied to the coil end portion 12a and droplets scattered during ejection contact the coil end portion 12a.

[0051] The third set value Re3 is set to a set rotation speed (17,000 rpm or higher). The relationship between the first set value Re1, the second set value Re2, and the third set value Re3 can be expressed as Re3>Re2>Re1.

[0052] With this configuration, when the electric motor M rotates at a first set rotational speed Re1, the first supply amount Q1 of coolant Lc is supplied from the ejection flow path 26 to the coil end portion 12a. When the rotational speed increases and the electric motor M rotates at a second set rotational speed Re2, the amount of coolant Lc supplied from the ejection flow path 26 to the coil end portion 12a is reduced to a second supply amount Q2. This makes it possible to reduce the amount of coolant Lc that has already been supplied from the first cooling flow path C1 to the coil end portion 12a that is blown away.

[0053] Furthermore, when the rotation speed of the electric motor M increases to the third set value Re3, the cooling liquid Lc ejected from the ejection passage 26 does not substantially come into contact with the coil end portion 12a, thereby preventing the cooling liquid Lc already supplied from the first cooling passage C1 from being blown away from the coil end portion 12a.

[0054] [Effects of the embodiment] The electric motor M is well cooled by a first cooling passage C1 that supplies coolant Lc from the radial outside of the stator S, and a second cooling passage C2 that supplies coolant Lc from the radial inside of the rotor R by centrifugal force accompanying the rotation of the rotor R.

[0055] The inclination angle α of the center line P in the ejection flow path 26 is set so that when the rotation speed per unit time is less than the second set value Re2, a portion of the coolant Lc ejected from the ejection flow path 26 comes into contact with the coil end portion 12a, and when the rotation speed reaches the second set value Re2, most of the coolant Lc ejected from the ejection flow path 26 does not come into contact with the coil end portion 12a.

[0056] Therefore, in the electric motor M, when the rotation speed of the rotor R becomes equal to or greater than the third set value Re3, most of the coolant Lc ejected from the ejection passage 26 does not come into contact with the coil end portion 12a and does not blow away the coolant Lc that has already been supplied via the first cooling passage C1. Therefore, in the electric motor M, it is possible to cool the coil end portion 12a with the coolant Lc supplied from the first cooling passage C1.

[0057] In this way, the inclination angle α of the center line P of the ejection flow path 26 is used to set the state in which the coolant Lc comes into contact with the coil end portion 12a (supply state) and the state in which it does not come into contact with the coil end portion 12a (non-supply state) in accordance with the rotation speed of the rotor R, so that the supply of the coolant Lc to the coil end portion 12a can be easily switched while maintaining a simple configuration.

[0058] [Another embodiment] The present invention may be configured as follows in addition to the above-described embodiments (common numbers and symbols are used to designate components having the same functions as those in the embodiments).

[0059] 3, 4, and 5, the electric motor M (rotating electric machine) can form the second cooling passage C2 by arranging a plurality of ejection passages 26 with different inclination angles α with respect to the cylindrical shaft 15. In other words, when the ejection passages 26 are formed at a plurality of locations that are equally positioned in the direction along the rotation axis X and do not overlap when viewed in the direction along the rotation axis X, the inclination angles α of the ejection passages 26 at the plurality of locations are made different.

[0060] The inclination angle α is shown as α1 in Fig. 3, α2 in Fig. 4, and α3 in Fig. 5. These angles are set in the relationship α1>α2>α3.

[0061] In the electric motor M of this alternative embodiment (a), ejection passages 26 with different inclination angles α are formed at different positions in a region along the circumferential direction of the outer periphery of the cylindrical shaft 15. As a result, when the rotation speed of the rotor R is relatively low (relatively low rotation speed), the electric motor M supplies the coolant Lc ejected at a low speed from the multiple ejection passages 26 to the inner periphery of the coil end portion 12a by centrifugal force, bringing the coolant Lc into contact with the coil end portion 12a and enabling cooling.

[0062] Furthermore, in the electric motor M of this alternative embodiment (a), as the rotation speed of the rotor R increases, the ejection speed of the coolant Lc ejected from the ejection passages 26 along the center line P increases, and the ejection passages 26 with the smaller inclination angle α among the multiple ejection passages 26 sequentially eject the coolant Lc in a direction that does not contact the coil end portions 12a. This makes it possible to gradually reduce the amount of coolant Lc that contacts the coil end portions 12a as the rotation speed of the rotor R increases, making it possible to gradually reduce cooling from the inner peripheral side of the coil end portions 12a.

[0063] (b) The electric motor M (rotating electric machine) has a cylindrical shaft 15, and the second cooling flow path C2 is configured by arranging ejection flow paths 26 at different positions in the direction along the rotation axis X. In this alternative embodiment (b), it is assumed that the inclination angles α of the ejection flow paths 26 at the multiple locations are set to the same value, but they may be different values.

[0064] In this alternative embodiment (b), the positions of the multiple ejection flow paths 26 are set so that when the rotor R rotates at a set rotational speed (17,000 rpm or higher) as described in the above embodiment, the cooling liquid Lc ejected from all of the multiple ejection flow paths 26 does not come into contact with the coil end portion 12a.

[0065] With this configuration, when the rotation speed of the rotor R is relatively small (relatively low rotation speed), the electric motor M enables cooling by causing the coolant Lc ejected from all of the multiple ejection flow paths 26 to come into contact with the inner circumference of the coil end portion 12a by centrifugal force.

[0066] Furthermore, in the electric motor M of this alternative embodiment (b), as the rotation speed of the rotor R increases, the coolant Lc ejected from the ejection flow path 26 at a position away from the stator core 11 in the direction along the rotation axis X can be sent in a direction that does not allow the coolant Lc to come into contact with the coil end portion 12a.

[0067] In this way, in the configuration of another embodiment (b), as the rotation speed of the rotor R increases, the number of ejection flow paths 26 that eject coolant Lc in the direction of contact with the coil end portion 12a is reduced, making it possible to gradually reduce the amount of coolant Lc that contacts the coil end portion 12a, and to gradually reduce the amount of coolant Lc that contacts the inner side of the coil end portion 12a.

[0068] (c) In the electric motor M (rotating electric machine), cooling channels are formed in the stator core 11 in the slots into which the coils are fitted or in the areas adjacent to the slots, through which the coolant Lc flows in a direction parallel to the rotation axis X, and the cooling form is set so that the coolant Lc flows in these cooling channels.

[0069] Since a plurality of slots are formed in the stator core 11, a plurality of flow paths for the coolant Lc are also required. For this reason, in this alternative embodiment (c), it is desirable to form dedicated pipes or the like within the housing for supplying the coolant Lc to each of the plurality of cooling flow paths formed in the stator core 11. In this way, the electric motor M of alternative embodiment (c) enables even better cooling of the coil end portions 12a.

[0070] (d) In the above embodiment, a cylindrical shaft 15 is used as the shaft of the electric motor M (rotating electric machine), but a cylindrical shaft may also be used. In such a case where a cylindrical shaft is used, a central flow passage 27 is formed coaxially with the rotational axis X of the shaft, and an ejection flow passage 26 is formed between this central flow passage 27 and the outer surface of the shaft.

[0071] Furthermore, the configurations disclosed in the above embodiments (including other embodiments, the same applies below) can be applied in combination with configurations disclosed in other embodiments, as long as no contradictions arise. Furthermore, the embodiments disclosed in this specification are examples, and the embodiments of the present invention are not limited to these, and can be modified as appropriate within the scope that does not deviate from the purpose of the present invention.

[0072] In the above-described embodiment, the following configurations are envisioned. (1) A stator S includes a stator core 11 arranged in a tubular region centered on a rotation axis X and a coil 12 having a coil end portion 12a protruding axially outward from the stator core 11; a rotor R arranged in the internal space of the stator core 11 and rotating about the rotation axis X; a first cooling flow path C1 that supplies a coolant Lc to the coil end portion 12a from the outside along the radial direction of the stator core 11; and a second cooling flow path C2 that supplies a coolant Lc to the coil end portion 12a from the outside along the radial direction of the stator core 11 by centrifugal force accompanying the rotation of the rotor R. and a second cooling flow path C2 capable of supplying coolant Lc from the inside in the direction perpendicular to the rotation axis, wherein, when the supply amount of coolant Lc supplied from the second cooling flow path C2 to the coil end portion 12a when the rotation speed per unit time of the rotor R is at a first set value Re1 is defined as a first supply amount Q1, and the supply amount of coolant Lc supplied from the second cooling flow path C2 to the coil end portion 12a when the rotation speed is at a second set value Re2 that is larger than the first set value Re1 is defined as a second supply amount Q2, the second supply amount Q2 is smaller than the first supply amount Q1.

[0073] According to this, in the rotating electrical machine (electric motor M), when the rotation speed per unit time of the rotor R is a first set value Re1, the second cooling flow path C2 supplies the coolant Lc to the coil end portion 12a at a first supply amount Q1. When the rotation speed per unit time of the rotor R is a second set value Re2 that is greater than the first set value Re1, the second cooling flow path C2 supplies the coolant to the coil end portion 12a at a second supply amount Q2 that is less than the first supply amount Q1. In other words, the amount of coolant Lc supplied to the coil end portion 12a can be reduced as the rotation speed of the rotor R increases. This prevents the coolant Lc already supplied to the coil end portion 12a from being blown away by the coolant Lc accelerated by centrifugal force and sprayed onto the coil end portion 12a. Therefore, cooling of the coil 12 by the coolant Lc is maintained even when the rotor R rotates at high speed.

[0074] (2) In the rotating electric machine (electric motor M) of (1), it is preferable that the amount of coolant Lc supplied from the second cooling flow path C2 to the coil end portion 12a becomes substantially zero when the rotation speed is equal to or greater than a third set value Re3 that is greater than the second set value Re2.

[0075] This prevents the cooling liquid, which has been accelerated by the action of centrifugal force, from coming into contact with the coil end portion 12a, and also suppresses a decrease in cooling capacity due to the blowing-away phenomenon of the cooling liquid Lc already supplied to the coil end portion 12a.

[0076] (3) In the rotating electric machine (electric motor M) of (1) or (2), the second cooling passage C2 has a shaft-side passage 25 formed in a shaft (cylindrical shaft 15) that rotates integrally with the rotor R, and an ejection passage 26 that communicates with the shaft-side passage 25, and it is preferable that the ejection passage 26 is formed with its center line P inclined at an inclination angle α with respect to the rotation axis X.

[0077] With this, for example, when the rotation speed per unit time of the rotor R is smaller than the first set value Re1, the coolant Lc ejected from the ejection passage 26 can be brought into contact with the coil end portion 12a by the action of centrifugal force. Also, when the rotation speed of the rotor R reaches the second set value Re2, it is possible to configure the coolant Lc to be ejected from the ejection passage 26 with a strong force, so that it is ejected toward the axial outside of the coil end portion 12a even in a situation where centrifugal force is acting. This makes it possible to reduce the amount of coolant Lc that comes into contact with the coil end portion 12a as the rotation speed increases.

[0078] (4) In the rotating electric machine (electric motor M) of (2), it is preferable that the center line P of the ejection flow passage 26 is directed axially outward from the coil end portion 12a.

[0079] The faster the rotation speed of the rotor R, the more the cooling liquid Lc ejected from the ejection passage 26 is ejected axially outward from the outer end of the coil end portion 12a, thereby preventing the cooling liquid Lc already supplied to the coil end portion 12a from being blown away.

[0080] In the rotating electric machine (electric motor M) of (Appendix), it is preferable that the second cooling passage C2 includes a plurality of ejection passages 26 having center lines P with different inclination angles α.

[0081] In this way, for example, when the rotation speed per unit time of the rotor R is less than a set value, the coolant Lc ejected from all of the ejection passages 26 comes into contact with the coil end portions 12a, and as the rotation speed increases, the coolant Lc ejected from some of the multiple ejection passages 26 can flow axially outward from the coil end portions 12a. In other words, with the above configuration, when the rotation speed of the rotor R is low, the coolant Lc is brought into contact with the coil end portions 12a to enable cooling, and the higher the rotation speed, the more the coolant Lc ejected from the ejection passages 26 comes into contact near the outer ends of the coil end portions 12a or does not come into contact with the coil end portions 12a, making it possible to prevent the coolant Lc already supplied to the coil end portions 12a from being blown away. [Industrial Applicability]

[0082] The present invention can be used in a rotating electric machine. [Explanation of symbols]

[0083] 11: stator core, 12: coil, 12a: coil end portion, 15: cylindrical shaft (shaft), 25: shaft side flow path, 26: ejection flow path, C1: first cooling flow path, C2: second cooling flow path, Lc: coolant, M: electric motor (rotating electric machine), P: center line, R: rotor, S: stator, X: rotation axis center, Q1: first supply amount, Q2: second supply amount, Re1: first set value, Re2: second set value, Re3: third set value, α: tilt angle

Claims

1. a stator including a stator core disposed in a tubular region centered on a rotation axis and a coil having a coil end portion protruding axially outward from the stator core; a rotor disposed in an internal space of the stator core and rotating around the rotation axis; a first cooling flow path that supplies a coolant to the coil end portion from an outer side in a radial direction of the stator core; a second cooling flow path that can supply the coolant to the coil end portion from an inner side in the radial direction by centrifugal force caused by rotation of the rotor, a supply amount of the coolant supplied from the second cooling flow passage to the coil end portion when the rotation speed per unit time of the rotor is at a first set value is set to a first supply amount; When the rotation speed is a second set value that is greater than the first set value, the supply amount of the coolant supplied from the second cooling flow path to the coil end portion is set to a second supply amount, The rotating electric machine wherein the second supply amount is less than the first supply amount.

2. 2. The rotating electric machine according to claim 1, wherein the amount of coolant supplied from the second cooling flow path to the coil end portion is substantially zero when the rotational speed is equal to or greater than a third set value that is greater than the second set value.

3. the second cooling flow path includes a shaft-side flow path formed in a shaft that rotates integrally with the rotor, and an ejection flow path that communicates with the shaft-side flow path, The rotating electric machine according to claim 1 , wherein the ejection passage has a center line inclined at an inclination angle with respect to the rotation axis.

4. The rotating electric machine according to claim 3 , wherein the center line of the ejection passage is directed axially outward beyond the coil end portion.

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