Rotating electrical machine

Abstract

A rotating electrical machine according to the present invention comprises: a stator including a stator core in which a slot is formed and a coil inserted into the slot; a rotor that faces the radial-direction inner side of the stator with a prescribed gap therebetween and rotates about an axis parallel to the axial direction; a housing that accommodates the stator and the rotor; and a guide member having a protrusion. The rotor comprises a discharge port through which a coolant is discharged toward a coil end that is part of the coil protruding from the slot. The guide member is disposed on at least a portion of the surface of the coil end that faces the discharge port, which is disposed radially outward of the coil end.

Description

Rotating electric machines

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

[0002] Rotating electric machines are used in a variety of industries, and are required to be highly efficient, small, lightweight, etc. At the same time, measures against temperature rises that occur during operation are also required. Patent Document 1 discloses a cooling structure for a motor that includes a stator consisting of a stator core and a coil, a housing that covers and fixes the stator, a rotating shaft that is rotatably supported by the housing via a plurality of bearings, a rotor that is fixed integrally to the rotating shaft, and an oil-cooled cooling device, wherein the stator core has a plurality of teeth that are arranged radially around the axis of the rotating shaft, and the coils are made up of a plurality of individual coils provided on each of the teeth, and these individual coils are made up of coil bobbins that surround the outer peripheries of the teeth and windings that are wound around the coil bobbins, The oil-cooled cooling device has an axial oil supply passage that supplies cooling oil through the axial center of the rotating shaft, and a discharge oil passage that communicates with this axial oil supply passage and discharges the cooling oil into the internal space of the housing, and each coil bobbin has a protrusion at the outer diameter end in the motor radial direction that protrudes at least in the motor axial direction beyond the winding diameter of the winding, and this protrusion has a repelling surface formed on it that repels the cooling oil that is discharged from the discharge oil passage and diffused in the internal space of the housing toward the outer diameter side in the motor radial direction, towards the winding.This discloses a cooling structure for a motor.

[0003] Japanese Patent Application Publication No. 2017-131078

[0004] The invention described in Patent Document 1 leaves room for improvement in the cooling of the coil.

[0005] A rotating electric machine according to a first aspect of the present invention is a rotating electric machine comprising: a stator including a stator core in which slots are formed and coils inserted into the slots; a rotor facing the radially inside of the stator with a predetermined gap therebetween and rotating around an axis parallel to the axial direction; a housing that houses the stator and the rotor; and a guide member having a protrusion, wherein the rotor has an outlet through which refrigerant is discharged toward the coil end, which is the part of the coil that protrudes from the slot, and the guide member is arranged on at least a part of the surface facing the outlet located radially outside the coil end.

[0006] According to the present invention, the coil can be cooled efficiently.

[0007] Schematic diagram of a vehicle equipped with a rotating electric machine. Cross-sectional view showing the configuration of a vehicle drive device according to an embodiment. Enlarged view of the vicinity of a guide member. Cross-sectional view of a guide member.

[0008] -Embodiment- Hereinafter, an embodiment of a rotating electrical machine will be described with reference to Figs.

[0009] Fig. 1 is a schematic diagram of a vehicle 1 equipped with a rotating electric machine. The vehicle 1 includes wheels 2 and a vehicle drive device 3 that drives the wheels 2. The vehicle drive device 3 is a drive unit that integrates devices such as a rotating electric machine and an inverter. The configuration of the rotating electric machine will be described in detail later with reference to Fig. 2 and subsequent figures.

[0010] An oil cooler 4 is connected to the vehicle drive device 3 via a first pipe 7. A first refrigerant pump 8 that pumps a first refrigerant is connected to the first pipe 7. The first refrigerant pump 8 supplies the first refrigerant to the vehicle drive device 3 to cool the vehicle drive device 3. A chiller 6 is connected to the oil cooler 4 via a second pipe 5, and a second refrigerant flows through the oil cooler 4, the second pipe 5, and the chiller 6. Heat exchange occurs in the oil cooler 4, and the heated first refrigerant is cooled by the second refrigerant. The second refrigerant is pumped by a second refrigerant pump 9 provided in the second pipe 5 and sent to the chiller 6. In the chiller 6, the heated second refrigerant is cooled by the wind generated when the vehicle 1 is traveling. The cooled second refrigerant is sent back to the oil cooler 4. Note that the second refrigerant will not be mentioned in the following description, and therefore the first refrigerant will also be referred to as the "refrigerant."

[0011] FIG. 2 is a cross-sectional view showing the configuration of the vehicle drive device 3. As shown in the lower right of FIG. 2, the side to which the vehicle drive device 3 transmits driving force is the "load side," the opposite side is the "anti-load side," the upward direction is referred to as the "upper" or "upper side," and the downward direction is referred to as the "lower" or "lower side." Furthermore, the direction along the rotor shaft 111 is defined as the "axial direction," the direction around the rotor shaft 111 is defined as the "circumferential direction," the radial direction (radial direction) centered on the rotor shaft 111 is defined as the "radial direction," and the direction perpendicular to the horizontal line is defined as the vertical direction. Note that FIG. 2 shows the vehicle drive device 3 in the same position as when it is in operation, and the bottom of FIG. 2 is the direction of gravity. Furthermore, for ease of explanation, the far side of FIG. 2 is defined as the "rear of the device," and the near side is defined as the "front of the device."

[0012] The vehicle drive device 3 includes a rotating electric machine 100, a reducer 200 that transmits the driving force of the rotating electric machine 100, and an inverter (not shown). The rotating electric machine 100 includes a rotor 110 disposed on the inner diameter side, a stator 140 that faces the outer diameter side of the rotor 110 with a predetermined gap therebetween, and a guide member 160. The rotor 110 and the stator 140 are housed in a housing 101. Of the two guide members 160 shown in FIG. 2 , the guide member 160 disposed on the load side relative to the stator 140 is actually located deeper in the housing 101 and therefore cannot be seen from the perspective of FIG. 2 . In this figure, the outline of the load-side guide member 160 is shown with a dashed line to clearly show the existence of two guide members 160.

[0013] The rotor 110 is provided on its inner peripheral side with a rotor shaft 111 rotatably supported by a first bearing 150, a second bearing 151, and a third bearing 152. The load side of the rotor shaft 111 is provided with a drive gear 201 constituting a reducer 200, a driven gear 202 that meshes with the drive gear 201 and transmits driving force to the drive gear 201, and a driven gear shaft 203 that is provided on the driven gear 202. The driven gear shaft 203 is supported by a fourth bearing 204 and a fifth bearing 205.

[0014] The stator 140 includes a stator core in which slots are formed, and a plurality of stator coils 141 inserted into the slots. However, the stator core is not shown in Fig. 2. Hereinafter, a part of the stator coil 141 that protrudes from the slot is referred to as a coil end 141E. In Fig. 2, the stator coil 141 is housed inside the stator core and is not shown clearly except for the coil end 141E, so the reference numeral 141 is enclosed in parentheses in Fig. 2.

[0015] The rotor shaft 111 is hollow, forming a shaft flow passage 120 through which a refrigerant flows. The refrigerant flowing through the shaft flow passage 120 cools the stator coil 141 and the rotor 110, and then falls into an oil pan 154 located below the rotating electrical machine 100. The refrigerant that falls and is collected in the oil pan 154 is pumped by the first refrigerant pump 8 and sent to the oil cooler 4 and the shaft flow passage 120. After cooling the stator coil 141 and the rotor 110, the refrigerant falls back into the oil pan 154. In this embodiment, the refrigerant is circulated in this manner to cool the stator coil 141 and the rotor 110. The cooling of the stator coil 141 by the refrigerant will be described in detail below.

[0016] The rotor 110 has multiple refrigerant paths 118 that extend from the center, where the rotor shaft 111 is inserted, to discharge ports 119 located on the outer periphery. As shown in FIG. 2 , the refrigerant paths 118 may be linear paths in the radial direction, or paths that combine radial, axial, and radial directions. The refrigerant moves from the shaft flow path 120 to the refrigerant paths 118 and from the refrigerant paths 118 to the discharge ports 119 by the force of pressure pumping by the first refrigerant pump 8 and the centrifugal force generated by the rotation of the rotor 110. The discharge ports 119 face upward, i.e., toward the coil ends 141E, and the refrigerant is discharged from the discharge ports 119 toward the coil ends 141E.

[0017] Coil ends 141E are locations where multiple coils are bent, and the discharged refrigerant is intended to adhere to coil ends 141E to cool stator coil 141. However, because there are gaps in coil ends 141E, some refrigerant passes through coil ends 141E. As will be described in more detail below, the refrigerant that passes through coil ends 141E and comes into contact with guide member 160 falls by gravity from protrusions 165 of guide member 160 and comes into contact with coil ends 141E. For this reason, guide member 160 is disposed at least vertically above coil ends 141E.

[0018] Figure 3 is an enlarged view of the vicinity of guide member 160. However, Figure 3 is not drawn to scale and is intended to clearly show the positional relationship. Guide member 160 is arranged radially outward from coil end 141E. Because Figures 2 and 3 are cross-sectional views, it can be understood that guide member 160 is arranged only directly above coil end 141E, but in reality it is also arranged radially outward from coil end 141E in places other than directly above coil end 141E.

[0019] Coil end 141E is a location where multiple coils are bent. Coil end 141E is composed of straight section 141E-1 continuing from the inside of the stator core, bent section 141E-2 where the bending begins, and end 141E-3 where the coil is bent approximately 180 degrees. Straight section 141E-1 has large gaps because the coils are lined up in parallel, while end 141E-3 has small gaps.

[0020] The axially inner end of the guide member 160 is referred to as the guide member inner end 161, and the axially outer end of the guide member 160 is referred to as the guide member outer end 162. The guide member 160 includes a base 160B having a substantially trapezoidal cross-sectional shape and a plurality of protrusions 165. The shape of the protrusions 165 is not particularly limited, as long as the cross-sectional area decreases toward the tip. The shape of the protrusions 165 is, for example, a hemisphere, a semi-cylinder, a cone, a triangular pyramid, a square pyramid, or the like.

[0021] The lower end of the base 160B is located radially inward, or in other words, lower, as it moves axially outward. Therefore, the refrigerant that comes into contact with the base 160B moves along the surface of the base 160B to the axially outward side and drips from the protrusions 165 to cool the coil end 141E. The guide member inner end 161 is located axially inward of the bent portion 141E-2. Therefore, the guide member 160 can collect the refrigerant leaking from the straight portion 141E-1, which has many gaps, to cool the coil end 141E. The guide member outer end 162 is located axially inward of the tip of the coil end 141E, i.e., the axially outer end of the end 141E-3. Therefore, the refrigerant that flows along the base 160B from the axially inner side can drip onto the end 141E-3. If the guide member outer end 162 were located axially outward of the tip of the coil end 141E, there would be a higher possibility that the refrigerant dripping from the guide member 160 would fall without contacting the coil end 141E, which is undesirable.

[0022] 4 is a cross-sectional view of the guide member 160. The guide member 160 also has a plurality of protrusions 165 in the front and rear directions of the device. That is, the guide member 160 has the protrusions 165 arranged two-dimensionally on the surface of the curved base 160B on the coil end 141E side. However, the arrangement of the protrusions 165 does not have to be regular. It is desirable that the rear end of the guide member 160 is closer to the front of the device than the coil end 141E. It is also desirable that the front end of the guide member 160 is further rearward than the coil end 141E.

[0023] The above-described embodiment provides the following advantageous effects. (1) The rotating electric machine 100 includes a stator 140 including a stator core with slots and coils inserted into the slots, a rotor 110 facing the radially inner side of the stator 140 with a predetermined gap therebetween, a housing 101 that houses the stator 140 and the rotor 110, and a guide member 160 having a protrusion 165. The rotor 110 includes a discharge port 119 from which a refrigerant is discharged toward the coil ends 141E, which are portions of the coils that protrude from the slots. The guide member 160 is disposed on at least a portion of the surface facing the discharge port 119 disposed radially outward of the coil ends 141E. This allows the coils constituting the rotating electric machine 100 to be efficiently cooled. Specifically, the refrigerant discharged from the discharge port 119 and passing through the gaps in the coil ends 141E adheres to the guide member 160, drips from the protrusion 165, and adheres to at least the coil ends 141E. Therefore, by simply providing the guide member 160, the amount of coolant adhering to the coil end 141E can be increased compared to conventional methods without requiring additional power, and as a result, the temperature of the rotating electric machine 100 can be lowered.

[0024] (2) At least a portion of guide member 160 is inclined vertically downward as it moves outward in the axial direction of rotating electric machine 100. This allows the coils that make up rotating electric machine 100 to be cooled efficiently. Specifically, this is as follows. End 141E-3 is located a long distance from discharge port 119, making it difficult for the refrigerant to adhere to it, and therefore has a high temperature. Therefore, it is more effective for the refrigerant that drips from guide member 160 to adhere to end 141E-3. Therefore, by inclining base 160B of guide member 160 vertically downward as it moves outward in the axial direction so that the refrigerant can easily adhere to end 141E-3, the coils that make up rotating electric machine 100 can be cooled efficiently.

[0025] (3) The coils constituting the stator core of the rotating electric machine 100 are segment coils using square wire coils. Although coils other than segment coils can be used in the rotating electric machine 100, the advantage of adopting the configuration of this embodiment is significant because segment coils tend to have gaps at the coil ends 141E.

[0026] (4) The axial position of the axially inner tip of guide member 160 is axially more inward than bent portion 141E-2 of coil end 141E. Therefore, the refrigerant that has passed through straight portion 141E-1 can adhere to guide member 160 and drip again toward coil end 141E.

[0027] (5) The axial position of the axially outer tip of the guide member 160 is axially more inward than the tip of the coil end 141E. Therefore, the refrigerant dripping from the axially outer side of the guide member 160 comes into contact with the coil end 141E, thereby efficiently cooling the coils that make up the rotating electric machine 100.

[0028] (Variation 1) In the embodiment described above, the base 160B of the guide member 160 is inclined vertically downward as it moves toward the outside in the axial direction of the rotating electric machine 100. However, this configuration is not essential, and the base 160B may be horizontal without any inclination, or may be inclined in the opposite direction, i.e., inclined vertically downward as it moves toward the inside in the axial direction of the rotating electric machine 100.

[0029] (Variation 2) In the embodiment described above, the axial position of the axially inner tip of guide member 160 is axially inner than bent portion 141E-2 of coil end 141E. However, the axial position of the axially inner tip of guide member 160 may be axially outer than bent portion 141E-2 of coil end 141E.

[0030] (Variation 3) In the above-described embodiment, the axial position of the axially outer tip of guide member 160 is axially inward of the tip of coil end 141E. However, the axial position of the axially outer tip of guide member 160 may be axially outward of the tip of coil end 141E.

[0031] The above-described embodiments and modifications may be combined with each other. Although various embodiments and modifications have been described above, the present invention is not limited to these. Other embodiments conceivable within the scope of the technical concept of the present invention are also included within the scope of the present invention.

[0032] 100: Rotating electric machine 101: Housing 110: Rotor 111: Rotor shaft 118: Refrigerant path 119: Discharge port 120: Shaft flow path 140: Stator 141: Stator coil 141E: Coil end 141E-1: Straight portion 141E-2: Bent portion 141E-3: End portion 160: Guide member 160B: Base portion 165: Protrusion

Claims

1. A rotating electric machine comprising: a stator including a stator core in which slots are formed and coils inserted into the slots; a rotor facing the radially inner side of the stator with a predetermined gap therebetween and rotating about an axis parallel to the axial direction; a housing that houses the stator and the rotor; and a guide member having a protrusion, wherein the rotor has an outlet port through which refrigerant is discharged toward the coil end, which is the portion of the coil that protrudes from the slot, and the guide member is arranged on at least a part of the surface facing the outlet port, which is arranged radially outside the coil end.

2. A rotating electric machine according to claim 1, wherein at least a portion of said guide member is inclined inward in the radial direction as it extends outward in the axial direction.

3. A rotating electric machine according to claim 1 or 2, wherein the coil is a segment coil.

4. A rotating electric machine according to claim 1 or 2, wherein the position of the inner tip of the guide member in the axial direction is located inside the bent portion of the coil end in the axial direction.

5. A rotating electric machine according to claim 1 or 2, wherein the position of the outer tip of the guide member in the axial direction is located inside in the axial direction relative to the tip of the coil end.

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