WO2022195920A1

WO2022195920A1 - Dynamo-electrical machine

Info

Publication number: WO2022195920A1
Application number: PCT/JP2021/031875
Authority: WO
Inventors: 英明後藤; 隆樹板谷
Original assignee: 日立Astemo株式会社
Priority date: 2021-03-18
Filing date: 2021-08-31
Publication date: 2022-09-22
Also published as: JPWO2022195920A1

Abstract

This motor (100) (dynamo-electrical machine) comprises a stator (10) and a housing (30) that accommodates the stator (10). The stator (10) is provided with teeth, a stator core (11), a fixed part (12), and a through-hole (15). A coil (14) is wound around the teeth. The stator core (11) retains the teeth. The fixed part (12) is formed on the radially outer side of the stator core (11) and is fixed to the housing (30). The through-hole (15) is formed along the axial direction and is provided in a position that overlaps the fixed part (12) and the teeth as seen from the radial direction.

Description

Rotating electric machine

The present invention relates to rotating electric machines.

In recent years, efforts have been made to reduce the size of motors by increasing their speed, but as the speed increases, the frequency of the motor's electromagnetic excitation force also increases, so reducing NV (Noise and Vibration) has become important. In addition, due to the increase in motor loss due to the increased speed of the motor, there is a demand for improved cooling performance.

A stator core is known that can achieve high cooling performance in a small space while suppressing performance deterioration of rotating electric machines (see Patent Document 1, for example).

Japanese Patent Application Laid-Open No. 2020-114085

Here, increasing the damping ratio of the transmission path from the teeth, which is the source of the electromagnetic excitation force, to the housing surface, which is the source of the sound, is effective in reducing NV.

However, with the technique disclosed in Patent Document 1, the attenuation ratio of the sound transmission path cannot be increased, and the noise from the housing cannot be reduced.

An object of the present invention is to provide a rotating electric machine capable of reducing noise from the housing caused by electromagnetic excitation forces generated in the teeth.

In order to achieve the above object, a rotating electric machine of the present invention includes a stator and a housing that houses the stator, the stator includes teeth around which coils are wound, stator cores that hold the teeth, a fixing portion formed radially outside the stator core and fixed to the housing; and a through hole formed along the axial direction and provided at a position where the fixing portion and the teeth overlap when viewed in the radial direction. , provided.

According to the present invention, it is possible to reduce the noise from the housing caused by the electromagnetic excitation force generated in the teeth. Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

1 is a perspective view of a motor according to an embodiment of the invention; FIG. 1 is a cross-sectional view of a motor according to an embodiment of the invention; FIG. FIG. 3 is a perspective view of the stator shown in FIG. 2; FIG. 3 is an explanatory view (radial cross section) of the action of the through hole shown in FIG. 2; 3 is an explanatory diagram (axial cross section) of the function of the through hole shown in FIG. 2; FIG. FIG. 10 is a cross-sectional view showing Modification 1 of the through hole; 5B illustrates the effect of the through holes shown in FIG. 5A; FIG. It is a sectional view showing modification 2 of a penetration hole. 6B illustrates the effect of the through holes shown in FIG. 6A; FIG. It is a figure which shows the other modification of a through-hole. It is a perspective view showing a circumferential groove. FIG. 4 is a partial cross-sectional view of the periphery of a coolant inlet having one opening; FIG. 4 is a partial cross-sectional view of the periphery of a coolant inlet having two openings; FIG. 3 is a cross-sectional view showing coolant flow paths provided inside the shaft and the rotor;

The configuration of the motor (rotating electric machine) according to the embodiment of the present invention will be described below with reference to the drawings. In addition, in each figure, the same code|symbol shows the same part.

(Motor configuration)
As shown in FIG. 1, the motor 100 mainly consists of a stator 10, a rotor 20 and a housing 30. As shown in FIG. A shaft 27 is attached to the rotor 20 .

As shown in FIG. 2, the motor 100 includes a stator 10 having a coil 14 and a core portion (stator core 11), a housing 30 containing the stator 10, and a rotating shaft (shaft 27) connected to the housing 30. a bearing 31; The stator 10 includes a through hole 15 extending along the rotation axis (shaft 27), and a fixing portion 12 that fixes the core portion (stator core 11) to the housing 30 and is formed radially outward. As shown in FIG. 3, the stator 10 has teeth (teeth 13) formed radially inward. The through-hole 15 is formed at a position overlapping the fixed portion 12 and the tooth portion (teeth 13) when viewed from the radial direction.

In other words, the fixing portion 12 is formed as an ear portion radially protruding from the outer surface of the core portion (the stator core 11). The axial through-hole (through-hole 15) is formed so as to overlap the entire ear portion when viewed from the radial direction.

As shown in FIGS. 4A and 4B, the low-rigidity region of the stator core provided with the through holes can increase the damping ratio on the path through which the electromagnetic excitation force generated in the stator is transmitted to the housing. It is possible to reduce the noise generated from

The transmission path and damping mechanism of the electromagnetic excitation force generated in the stator 10 will be described in detail. In this embodiment, axial through-holes (through-holes 15 ) are provided on the inner diameter side of the fixing portion 12 (ear portion), which is the core back portion of the stator core 11 . Due to the difference in hole shape (rigidity), specific frequency components can be reduced as shown below.

In this embodiment, the stator 10 is fixed to the housing 30 via the fixing portion 12 . When the coil 14 is energized, an electromagnetic excitation force is generated in the teeth (teeth 13). A through hole 15 is provided on the transmission path through which the electromagnetic excitation force is transmitted to the housing 30 . The through holes 15 reduce the stiffness of the transmission path and increase the damping ratio so that the equivalent radiated power level at the surface of the housing 30 can be reduced. Further, by adjusting the rigidity of the transmission path according to the shape of the through-hole 15, the spring constant of the transmission path is changed (frequency=SQRT(k/m)), and any frequency can be reduced. where k=spring constant, m=mass, SQRT denotes a function that returns the square root of its argument.

As described above, the electromagnetic excitation force generated in the teeth (teeth 13) of the stator 10 is transmitted from the stator core 11 to the housing 30 via bolts, fixing surfaces, etc., and radiated from the surface of the housing 30 as noise. In the transmission path, the axial through-hole 15 is provided in the core-back portion in the middle of the transmission path from the teeth 13 to the housing 30 to provide a low-rigidity region on the transmission path, thereby increasing the damping ratio. . By increasing the damping ratio of the transmission path, noise generated on the surface of the housing 30 can be reduced.

The cooling performance is improved by providing axial through holes (through holes 15) along the entire periphery of the core-back outer peripheral portion. Further, by providing the through holes 15 around the entire periphery, the overall radiation power level is further reduced.

The above features can be summarized as follows.

As shown in FIGS. 2 and 3, the motor 100 (rotating electrical machine) includes at least a stator 10 and a housing 30 that accommodates the stator 10 . The stator 10 includes teeth 13 , stator cores 11 , fixed portions 12 and through holes 15 . Coils 14 are wound around the teeth 13 . Stator core 11 holds teeth 13 . The fixed portion 12 is formed radially outside the stator core 11 and fixed to the housing 30 with a fixing member such as a bolt. The through-holes 15 are formed along the axial direction and provided at positions overlapping the fixed portion 12 and the teeth 13 when viewed in the radial direction. Accordingly, noise from the housing 30 caused by the electromagnetic excitation force generated in the teeth 13 can be reduced.

A plurality of through holes 15 shown in FIG. 3 are provided along the entire circumference of the stator core 11 . Although it is not essential to flow an insulating coolant such as oil through the through holes 15, when the coolant is caused to flow through the through holes 15 provided along the entire circumference, the stator 10 can be uniformly cooled in the circumferential direction. .

(Modification 1 of through-hole)
In the example of FIG. 5A , one through-hole 15 is provided for each fixed portion 12 and covers the radially outer side of a plurality of teeth 13 adjacent to the fixed portion 12 . In other words, the through hole 15 has a rectangular cross section in the axial direction and extends over the plurality of teeth 13 . Thereby, as shown in FIG. 5B, the equivalent radiation power level on the low frequency side can be reduced.

(Modification 2 of through hole)
In the example of FIG. 6A , a plurality of through holes 15 are provided for each fixing portion 12 . The plurality of through holes 15 cover the radially outer sides of the plurality of teeth 13 adjacent to the fixing portion 12 . Thereby, as shown in FIG. 6B, the equivalent radiation power level on the high frequency side can be reduced.

(Other modified examples of through holes)
As shown in FIG. 7, the rigidity is adjusted by changing the shape of the axial through hole (through hole 15) provided in the stator core 11, and the spring constant of the vibration transmission path is changed (frequency = SQRT (k/m)). Any frequency can be reduced by where k=spring constant, m=mass, SQRT denotes a function that returns the square root of its argument.

(circumferential groove)
Due to the increase in motor loss due to the speeding up of the motor, there is a problem that the cooling performance of the conventional water jacket system is insufficient. Here, it is effective to directly cool the stator core by using insulating oil such as ATF (Automatic Transmission Fluid) as a coolant.

As shown in FIG. 8, the housing 30 has a groove forming portion 34 forming a tubular circumferential groove 34A through which the coolant flows. The groove forming portion 34 is formed toward the coil end face (the end face 11A in FIG. 2) of the stator 10 and connected to the coil end face to form the axial through hole (the through hole 15) and the circumferential groove 34A. connect.

In other words, the circumferential groove 34A is provided as a groove that opens toward the stator 10 in the stator fixing portion (groove forming portion 34) of the housing 30. The axial through hole (through hole 15) is provided in the stator core 11 as a hole penetrating in the axial direction. By fixing the stator 10 to the fixing surface (stator fixing surface 33) of the housing 30, the circumferential groove 34A and the axial through-hole (through-hole 15) are connected at the stator core end surface. By supplying the coolant to the circumferential grooves 34A, the coolant is supplied to the axial through-holes (the through-holes 15), and the stator 10 can be directly cooled.

In addition, the circumferential groove 34A is formed in the groove forming portion 34 in a cylindrical shape with an opening on the stator 10 side so as to communicate with all the axial through holes (through holes 15). The housing 30 shown in FIG. 8, as shown in FIG. 9A, includes a coolant inlet 35 having one opening 35A for supplying coolant to the groove (circumferential groove 34A).

The above features can be summarized as follows. The housing 30 is connected to the through hole 15 of the stator 10 and has a cylindrical groove (circumferential groove 34A) through which the coolant flows. Thereby, the stator 10 can be cooled.

(Modified example of refrigerant inlet)
In the example of FIG. 9B, the housing 30 includes a coolant inlet 35 having two or more openings 35A that supply coolant to the groove (circumferential groove 34A).

By increasing the opening 35A of the coolant inlet 35 for supplying the coolant to the circumferential groove 34A, the flow velocity in the circumferential groove 34A becomes constant, and the flow rate to the axial through hole (through hole 15) is increased. Since the inflow amount of the coolant becomes uniform, the temperature gradient within the stator 10 is alleviated.

The coolant inlet 35 has a function of communicating the circumferential groove 34A provided in the housing 30 with a coolant cooling device (not shown) that cools the coolant. The coolant inlet 35 shown in FIG. 9B has two or more openings 35A (communicating portions) to the circumferential groove 34A, and has one communicating path with the coolant cooling device.

(shaft and rotor)
In the example of FIG. 10, the motor 100 includes a shaft 27 having a first flow path (flow path 29) through which coolant flows, and a rotor 20 having a second flow path (flow path 22). The second flow path (flow path 22) of the rotor 20 is connected to the first flow path (flow path 29) of the shaft 27, and supplies coolant to the coil 14 on the groove (circumferential groove 34A) side.

Specifically, the motor 100 includes a first end ring (end ring 23) and a second end ring (end ring 24). The first end ring (end ring 23) is provided on one end face of the rotor 20 and connects the first flow path (flow path 29) of the shaft 27 and the second flow path (flow path 22) of the rotor 20. It has a third channel (channel 25). The second end ring (end ring 24) is provided on the other end surface of the rotor 20 and directs the coolant from the second flow path (flow path 22) of the rotor 20 to the coil 14 on the side of the groove (circumferential groove 34A). It has a fourth flow path (flow path 26) for guiding.

In the structure shown in FIG. 2, since the circumferential groove 34A and the axial through hole (through hole 15) are fixed so as to communicate with each other, the refrigerant cannot be supplied to the coil end on the side of the circumferential groove 34A. Therefore, when the coolant is supplied to the rotor 20, by adopting a structure in which the coolant is supplied from the anti-circumferential groove side to the circumferential groove side, the coolant that has cooled the rotor 20 is discharged to the circumferential groove side. Thus, the coolant discharged from the rotor 20 is used to cool the coil ends on the circumferential groove side. The temperature gradient can be reduced by cooling both coil ends with a coolant.

As described above, according to this embodiment, the noise from the housing 30 caused by the electromagnetic excitation force generated in the teeth 13 can be reduced. Also, the cooling performance of the motor 100 can be improved.

It should be noted that the present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the described configurations.

In addition, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Moreover, it is possible to add, delete, or replace part of the configuration of each embodiment with another configuration.

The configuration of the above embodiment can be applied to various motors such as PM (Permanent Magnet) motors and induction motors. In addition, the embodiment of the present invention may be the following aspects.

(1). A stator 10 having a coil 14 and a core portion (stator core 11), a housing 30 that houses the stator 10, and a bearing 31 that is connected to the housing 30 and supports a rotating shaft (shaft 27). Reference numeral 10 denotes a through hole 15 extending along the rotation axis (shaft 27), a fixing portion 12 that fixes the core portion (stator core 11) to the housing 30 and is formed radially outward, and a tooth portion (teeth 13) formed inside the through hole 15 is formed at a position overlapping the fixing portion 12 and the tooth portion (teeth 13) when viewed from the radial direction. rotating electric machine.

(2). The housing 30 has a groove forming portion 34 forming a (cylindrical) circumferential groove 34A through which a coolant flows. The axial through-hole (through-hole 15) and the circumferential groove 34A are connected by connecting to the coil end end face.

(3). A coolant inlet 35 for supplying coolant to a circumferential groove 34A provided in a stator fixing surface 33 of the housing 30 is provided in the housing 30. As shown in FIG. Two or more openings 35A may be provided for the circumferential grooves 34A of the coolant inlet 35 .

(4). The coolant supplied to the circumferential groove 34A passes through the axial through-hole (through-hole 15) and is supplied to the coil end portion on the side opposite to the fixed surface. The coolant supplied to flow path 29 provided in shaft 27 is supplied to flow path 22 in rotor core 21 through flow path 25 provided in the rotor end ring (end ring 23). The coolant discharged from the rotor 20 is supplied to the coil ends on the circumferential groove 34A side.

(1)-(4) make it difficult for the electromagnetic excitation force generated in the stator to be transmitted to the housing, thereby reducing the equivalent radiation power level on the surface of the housing and improving noise. By changing the shape of the hole provided on the inner diameter side of the fixed part 12 (ear part), any frequency component can be reduced, and the tone can be adjusted by reducing the maximum NV value or reducing a specific frequency component.

DESCRIPTION OF SYMBOLS 10... Stator 11... Stator core 11A... End surface 12... Fixed part 13... Teeth 14... Coil 15... Through hole 20... Rotor 21...

Rotor cores

23, 24... End rings 22, 25, 26, 29... Flow path 27... Shaft 28... Gear 30 Housing 31 Bearing 32 Gearbox 33 Stator fixing surface 34 Groove forming portion 34A Circumferential groove 35 Refrigerant inlet 35A Opening 100 Motor

Claims

comprising a stator and a housing that houses the stator,
The stator is
teeth around which the coil is wound;
a stator core that holds the teeth;
a fixing portion formed radially outside the stator core and fixed to the housing;
a through hole formed along the axial direction and provided at a position overlapping the fixed portion and the tooth when viewed from the radial direction;
A rotating electric machine.
The rotating electric machine according to claim 1,
The housing is
A rotary electric machine, comprising: a tubular groove connected to the through hole of the stator and through which a coolant flows.
The rotating electrical machine according to claim 2,
The housing is
A rotating electric machine, comprising: a coolant inlet having two or more openings for supplying a coolant to the groove.
The rotating electrical machine according to claim 2,
a shaft having a first flow path through which a coolant flows;
a rotor connected to the first flow path of the shaft and having a second flow path that supplies coolant to the coil on the groove side.
The rotating electrical machine according to claim 2,
The through hole is
One provided for each fixed part,
A rotary electric machine that covers radially outer sides of the plurality of teeth adjacent to the fixed portion.
The rotating electrical machine according to claim 2,
The through hole is
A plurality are provided for each of the fixing portions,
The plurality of through holes are
A rotary electric machine that covers radially outer sides of the plurality of teeth adjacent to the fixed portion.
The rotating electrical machine according to claim 2,
The through hole is
A rotary electric machine, wherein a plurality of rotating electric machines are provided along the entire circumference of the stator core.
The rotating electric machine according to claim 4,
a first end ring provided on one end face of the rotor and having a third flow path connecting the first flow path of the shaft and the second flow path of the rotor;
a second end ring that is provided on the other end surface of the rotor and has a fourth flow path that guides the coolant from the second flow path of the rotor to the coil on the groove side. electric machine.