JP6857514B2 - Rotating machine stator - Google Patents

Description

The present invention relates to a stator of a rotary electric machine.

The stator of a rotary electric machine used in a hybrid vehicle, an electric vehicle, or the like includes an annular stator yoke, a plurality of teeth protruding inward at equal intervals in the radial direction from the stator yoke, and a radial outer side from the outer peripheral surface of the stator yoke. A stator core with a flange that protrudes into the through hole and is provided with a through hole, and a coil that is inserted into a slot formed between adjacent teeth, and the stator core is fixed to the housing by a bolt that is inserted through the through hole of the flange. ing.

Japanese Unexamined Patent Publication No. 2016-171636

In the rotary electric machine described above, the stator core is fixed to the housing by inserting a bolt into a through hole provided in a flange protruding from the stator yoke. However, as described in Patent Document 1, for example, in the configuration in which the flanges are provided at regular intervals in the circumferential direction, the torque ripple of the rotary electric machine increases due to the flange protruding from the stator yoke formed of the same material as the stator core. there's a possibility that. For example, as shown in FIG. 3, in the rotary electric machine 1 in which flanges 6 are provided on the outer peripheral surface of the stator yoke 4 at intervals of 60 degrees, the presence of the flanges 6 causes a magnetic imbalance, and the magnetic imbalance occurs. Since the rotor 2 is periodically affected by the equilibrium, the torque fluctuates.

Hereinafter, the principle of generating torque ripple in the rotary electric machine 1 shown in FIG. 3 will be described with reference to FIGS. 4 (a) and 4 (b) and FIGS. 5 (a) and 5 (b). FIG. 4 (a) is a conceptual diagram of a portion corresponding to two magnetic pole portions of a rotary electric machine rotor and a stator without a flange 6, and FIG. 4 (b) is a conceptual diagram of FIG. 4 (a). It is a graph which shows the torque change of 1 cycle corresponding to the structure. 5 (a) is a conceptual diagram of a portion of the rotary electric machine 1 shown in FIG. 3 corresponding to the two magnetic pole portions of the rotor 2 and the stator 3, and FIG. 5 (b) is a conceptual diagram of the portion corresponding to the two magnetic pole portions. It is a graph which shows the torque change of one cycle corresponding to the structure of (a).

As shown in FIG. 4A, when viewed from each phase (U phase, V phase, W phase) of the stator 3, the magnetic pole portion of the rotor 2 passes twice (N pole, S pole) in one cycle. To do. Since each phase has a torque peak, the torque change in one cycle has a torque peak of 6 times (= 3 phases × 2 magnetic pole portions) as shown in FIG. 4 (b). This torque ripple is a basic order and is an unavoidable fluctuation, but if there is another magnetic imbalance, torque ripple of that order will occur. The flange 6 shown in FIG. 3 is formed of an electromagnetic steel material of the same material as the stator yoke 4 (stator core), and is provided on a part of the outer peripheral surface of the stator yoke 4, so that the flange 6 is magnetically non-magnetic. It causes equilibrium.

Since the flanges 6 are provided at regular intervals of 60 degrees, the flanges 6 are located on the specific phase of the stator 3 (V phase in FIG. 5A) as shown in FIG. 5A. Therefore, the magnetic flux easily flows on the stator yoke 4 side of the specific phase, and the magnetic flux is relatively difficult to flow on the stator yoke 4 side of the other two phases (U phase and W phase in FIG. 5A). The result is a magnetic imbalance. In this way, the torque fluctuates due to the magnetic imbalance caused by the flanges 6 provided at regular intervals. In the example shown in FIG. 3, the magnetic poles of the rotor 2 pass twice (N pole and S pole) with respect to each flange 6, and six flanges 6 are provided at intervals of 60 degrees. Twelve-order (= 360 degrees / 60 degrees x 2 magnetic poles) torque ripple occurs. As a result, as shown in FIG. 5 (b), in addition to the torque ripple of the basic order shown in FIG. 4 (b), a torque ripple in which the 12th order torque ripple is combined is generated.

Since the torque ripple described above is the main cause of the annular vibration of the rotor 2, if the torque ripple can be reduced, the vibration and noise of the rotor 2 can be further suppressed. Therefore, in order to improve the quietness of the vehicle equipped with the rotary electric machine, it is required to reduce the torque ripple. Further, if the torque ripple can be reduced, the torque of the rotary electric machine is improved.

An object of the present invention is to provide a stator of a rotary electric machine capable of reducing torque ripple.

In order to achieve the above object, the invention according to claim 1 is
An annular stator yoke (for example, the stator yoke 33 in the embodiment described later), a plurality of teeth protruding from the stator yoke in one radial direction at equal intervals (for example, the teeth 34 in the embodiment described later), and the like. A plurality of through holes (for example, through holes 37 in the embodiment described later) for projecting from the stator yoke in the other direction in the radial direction and for fastening with the housing (for example, the housing 40 in the embodiment described later) by bolts. A stator core having a flange (for example, the flange 36 in the embodiment described later) and a stator core (for example, the stator core 31 in the embodiment described later).
A rotary electric machine (for example, a rotary electric machine) including a coil (for example, a coil 32 in the embodiment described later) inserted into a slot (for example, a slot 35 in the embodiment described later) formed between the adjacent teeth. It is a stator of the rotary electric machine 10) in the embodiment described later (for example, the stator 30 in the embodiment described later).
The plurality of flanges arranged in the circumferential direction of the stator yoke are arranged so that the circumferential phase difference of the flanges adjacent to each other in the circumferential direction deviates from the uniform arrangement over the entire circumference .
The circumferential phase difference of the flanges adjacent to each other in the circumferential direction among the plurality of flanges has two values.
On the outer periphery of the other radial direction of the stator yoke, a flange having a first circumferential phase difference (for example, the circumferential phase difference θ1 in the embodiment described later) and a second circumferential phase difference (for example) For example, the arrangement of the flanges having the circumferential phase difference θ2) in the embodiment described later is alternately performed over the entire circumference.
When the number of the plurality of flanges provided over the entire circumference of the other outer circumference of the stator yoke in the radial direction is 2N.
The first circumferential phase difference is "360 / 8N x 5" degrees, and the second circumferential phase difference is "360 / 8N x 3" degrees.
The number of pole pairs of the rotary electric machine is 2N.

The invention according to claim 2 is the invention according to claim 1 .
The stator core is formed by laminating a steel plate laminate formed by laminating a plurality of steel plates with multiple times of N so as to have different circumferential phases from each other.

According to the invention of claim 1, since the positions of the flanges in the circumferential direction are not uniform, the torque ripple caused by the magnetic imbalance caused by the flange can be canceled by the torque ripple by different flanges. As a result, the torque ripple of the rotary electric machine can be reduced.

According to the invention of claim 1 , there is a position between the torque ripple caused by the magnetic imbalance caused by the flange and the torque ripple caused by the flange having the first circumferential phase difference or the second circumferential phase difference. Due to the phase difference, when both torque ripples are combined, they cancel each other out. Therefore, the torque ripple of the rotary electric machine can be reduced.

According to the invention of claim 1, the torque ripple due to the two flanges having a circumferential phase difference of "360 / 8N x 5" degrees or "360 / 8N x 3" degrees has a phase difference of about 180 degrees. The torque ripples caused by the magnetic imbalance caused by the flanges cancel each other out. Therefore, the reduction rate of torque ripple can be maximized.

According to the second aspect of the present invention, the transfer product capable of reducing the distortion of the stator core and making the magnetic characteristics of the stator core uniform can be performed by using a single type of steel plate.

It is a radial sectional view of the rotary electric machine of one embodiment. It is a conceptual diagram which saw the part corresponding to the three magnetic pole portions of the rotor and the stator of the rotary electric machine shown in FIG. 1 from the axial direction, and is the graph which shows the torque change in one cycle. It is a radial cross-sectional view of a rotary electric machine in which flanges are provided at equal intervals. (A) is a conceptual diagram of a portion corresponding to two magnetic pole portions of a rotary electric machine rotor and a stator without a flange as viewed from the axial direction, and (b) is a one-cycle cycle corresponding to the configuration of (a). It is a graph which shows the torque change. (A) is a conceptual diagram of a portion corresponding to two magnetic pole portions of the rotor and the stator of the rotary electric machine shown in FIG. 3 as viewed from the axial direction, and FIG. 3B is a conceptual diagram corresponding to the configuration of (a) 1. It is a graph which shows the torque change of a period.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings shall be viewed in the direction of the reference numerals.

FIG. 1 is a radial cross-sectional view of the rotary electric machine of one embodiment. The rotary electric machine 10 shown in FIG. 1 includes a rotor 20, a stator 30 which is arranged so as to face each other on the radial outer side of the rotor 20 with a slight gap, and a housing 40 which houses and fixes the stator 30 inside. The rotary electric machine 10 is configured to rotate the rotor 20 by energizing the coil 32 wound around the teeth 34 of the stator 30.

The rotor 20 has a rotating shaft 21 rotatably supported by the housing 40, a rotor core 22 fixed to the outer peripheral surface of the rotating shaft 21, and a plurality of permanent magnets 24 embedded in the rotor core 22, so-called permanent. It is a rotor of a magnet-embedded rotary electric machine (IPM motor).

The rotor core 22 is formed by laminating a plurality of electromagnetic steel plates having substantially the same shape, and has a substantially annular shape. Each electrical steel sheet has a shaft insertion hole 26 through which the rotating shaft 21 is inserted in the central portion thereof, and a plurality of pair of magnet insertion holes 23, 23 are formed in the outer peripheral portion thereof at predetermined intervals in the circumferential direction. There is. Further, the pair of magnet insertion holes 23, 23 have a substantially V-shape extending toward the outer peripheral surface of the rotor core 22 facing the stator 30.

The electrical steel sheet is made of a magnetic material, and two permanent magnets 24, 24 inserted into the pair of magnet insertion holes 23, 23 form a pair to form one magnetic pole portion 25. That is, two permanent magnets 24, 24 having the same magnetization direction are inserted into the pair of magnet insertion holes 23, 23 constituting one magnetic pole portion 25, and the permanent magnets are inserted so that the magnetic poles are alternately inverted in the circumferential direction. The magnet. For example, as shown in FIG. 1, assuming that the outer peripheral side of the magnetic pole portion 25a is the north pole, the adjacent magnetic pole portion 25b is configured such that the permanent magnet 24 is inserted into the magnet insertion hole 23 so that the outer peripheral side thereof is the south pole. Has been done.

The stator 30 has a stator core 31 and a coil 32.

The stator core 31 is configured by laminating (rotational buildup) of a plurality of steel plate laminates so as to have different circumferential phases from each other. The steel plate laminate is formed by laminating a plurality of steel plates such as electromagnetic steel plates. The product thickness may be the same or different. The steel plate constituting the steel plate laminate is provided with an insulating layer (not shown) on one side or both sides of the steel plate so that adjacent steel plates in the axial direction do not conduct with each other.

Each steel plate has an annular stator yoke 33, a plurality of teeth 34 projecting radially inward from the stator yoke 33 at equal intervals, slots 35 formed between adjacent teeth 34 at equal intervals in the circumferential direction, and a stator. It is a plate-shaped member having a flange 36 protruding outward in the radial direction from the yoke 33 and having a through hole 27, and is formed by pressing out an electromagnetic steel plate. In the present embodiment, 2N flanges (where N is a natural number of 2 or more), that is, an even number of flanges 36 of 4 or more are provided over the entire circumference of the stator yoke 33 in the circumferential direction. The example shown in FIG. 1 is the case of N = 3.

When a plurality of steel plate laminates formed by laminating a plurality of steel plates are laminated, a plurality of slots 14 penetrating in the axial direction are formed in the stator core 13 at equal intervals in the circumferential direction. A coil 32 formed by a winding (not shown) wound around the teeth 34 is inserted into the slot 35.

Further, when a plurality of steel plate laminates are laminated, through holes 37 penetrating in the axial direction are formed in each flange 36 of the stator core 13. The stator core 13 is fixed to the housing 40 by inserting a bolt (not shown) into the through hole 37 and fastening the stator core 13 to the housing 40. The flange 36 has a pair of inclined surfaces 36d and 36e that approach the virtual straight line IL connecting the center O of the rotary electric machine 10 and the through hole 37 as viewed in the axial direction toward the outer diameter side.

In the present embodiment, the six (2N) flanges 36 arranged in the circumferential direction of the stator yoke 33 are not at equal intervals, and the circumferential phase difference between the flanges 36 adjacent to each other in the circumferential direction is the entire circumference of the stator yoke 33. It is arranged so as to deviate from the even arrangement. That is, the circumferential phase difference of the flanges 36 adjacent to each other in the circumferential direction among the six flanges 36 has two values such as 75 degrees (= 360 degrees / 8N × 5) and 45 degrees (= 360 degrees / 8N × 3). The arrangement of the flange 36 having a circumferential phase difference θ1 of 75 degrees and the arrangement of the flange 36 having a circumferential phase difference θ2 of 45 degrees are alternately performed over the entire circumference of the stator yoke 33. The circumferential phase difference between the adjacent flanges 36 is an angle formed by two virtual straight lines IL connecting the center O of the rotary electric machine 10 and the through holes 37 of each flange 36 as viewed in the axial direction.

As described above, in the present embodiment, the circumferential phase differences of the flanges 36 adjacent to each other in the circumferential direction are not equalized, and the predetermined value θ advances from the circumferential phase difference θ0 (60 degrees = 360 degrees / 2N) when they are equal. Even numbers such that the circumferential phase difference θ1 (75 degrees = 360 degrees / 8N × 5) and the circumferential phase difference θ2 (45 degrees = 360 degrees / 8N × 3) delayed by the same predetermined value θ are arranged alternately. Two (2N) flanges 36 are arranged over the entire circumference of the stator yoke 33. According to this configuration, there is a phase difference between the torque ripple caused by the magnetic imbalance caused by one flange 36 and the torque ripple caused by the magnetic imbalance caused by the flanges 36 adjacent to each other in the circumferential direction. Occurs.

The phase difference Δ between the two torque ripples caused by the adjacent flanges 36 is obtained by the following equation (1). However, θ is the circumferential phase difference θ0 − circumferential phase difference θ2 when 2N flanges 36 are evenly arranged, P is the polar logarithm of the rotor, and the constant 2 is the torque ripple order of the second order. It depends.
Δ = θ × P × 2… (1)

In the example shown in FIG. 1, since θ = 15 degrees and P = 6, Δ = 180 degrees. That is, as shown in FIG. 2, the torque ripple 101a caused by the flange 36a and the torque ripple 101b caused by the flange 36b having a circumferential phase difference θ2 of 45 degrees (= 360 degrees / 8N × 3) with respect to the flange 36a. Since there is a phase difference of about 180 degrees between the two torque ripples 101a and 101b, both torque ripples 101a and 101b cancel each other out. Therefore, the reduction rate of torque ripple can be maximized. The torque ripple caused by the flange 36c and the torque ripple caused by the flange 36b having a circumferential phase difference θ1 of 75 degrees (= 360 degrees / 8N × 5) with respect to the flange 36b are also approximately 180 degrees. The explanation that both torque ripples cancel each other out due to the phase difference has the same meaning.

As described above, in the present embodiment, there is a phase difference of 180 degrees between the torque ripple generated by one flange 36 and the torque ripple generated by the flanges 36 adjacent to each other in the circumferential direction, and both torque ripples are combined. And cancel each other out. As a result, the torque ripple caused by the flange 36 included in the output torque of the rotary electric machine 10 is reduced.

Further, in the rotary electric machine 10 of the present embodiment shown in FIG. 1, the arrangement of the flange 36 having the circumferential phase difference θ1 and the arrangement of the flange 36 having the circumferential phase difference θ2 alternate over the entire circumference of the stator yoke 33. It is done in. Therefore, when a plurality of steel plate laminates are transposed, they are transposed "360 / (θ1 + θ2)" times or a multiple thereof every θ1 + θ2. Therefore, in the present embodiment, the transfer product capable of reducing the distortion of the stator core 31 and making the magnetic characteristics uniform can be performed by using a single type of steel plate.

The present invention is not limited to the above-described embodiment, and can be appropriately modified, improved, and the like. For example, in the above embodiment, when the number of flanges 36 is 2N, the circumferential phase difference θ1 is “360 degrees / 8N × 5” degrees (= 75 degrees), and the circumferential phase difference θ2 is “360 degrees / 8N”. The configuration of x3 degrees (= 45 degrees) has been described as an example. For example, the circumferential phase difference θ1 is “360 degrees / 12N × 7” degrees (= 70 degrees), and the circumferential phase difference θ2 is “360 degrees”. The configuration may be degrees / 12N × 7 ”degrees (= 50 degrees). However, in this case, since the phase difference between the torque ripples caused by the flanges 36 adjacent to each other in the circumferential direction is not 180 degrees, the reduction rate of the torque ripples is lower than that of the example of the above embodiment.

If the number of flanges 36 is reduced to three and evenly arranged, the torque ripple is reduced by the reduction in the number of flanges, but the number of fastenings between the stator core 31 and the housing 40 is reduced, so that the fixing force of the stator core 31 is reduced. descend.

Further, although the magnet insertion holes 23 are paired and have a substantially V-shaped shape, the structure of the magnetic poles is not limited to a pair, and may be one, three or more, or a linear arrangement other than the V-shape.

10 Rotating electric machine 20 Rotor 21 Rotating shaft 22 Rotor core 23 Magnet insertion hole 24 Permanent magnet 25, 25a, 25b Magnetic pole 30 Stator 31 Stator core 32 Coil 33 Stator yoke 33a Outer peripheral surface 34 Teeth 35 Slot 36 Flange 37 Through hole 40 Housing

Claims (2)

An annular stator yoke, a plurality of teeth protruding from the stator yoke in one radial direction at equal intervals, and a plurality of teeth protruding from the stator yoke in the other radial direction and provided with through holes for fastening to the housing with bolts. With a flange, with a stator core,
A stator of a rotary electric machine provided with a coil inserted into a slot formed between adjacent teeth.
The plurality of flanges arranged in the circumferential direction of the stator yoke are arranged so that the circumferential phase difference of the flanges adjacent to each other in the circumferential direction deviates from the uniform arrangement over the entire circumference .
The circumferential phase difference of the flanges adjacent to each other in the circumferential direction among the plurality of flanges has two values.
On the outer periphery of the other radial direction of the stator yoke, the arrangement of the flange having the first circumferential phase difference and the arrangement of the flange having the second circumferential phase difference are alternately performed over the entire circumference.
When the number of the plurality of flanges provided over the entire circumference of the other outer circumference of the stator yoke in the radial direction is 2N.
The first circumferential phase difference is "360 / 8N x 5" degrees, and the second circumferential phase difference is "360 / 8N x 3" degrees.
The stator of the rotary electric machine, the number of pole pairs of the rotary electric machine is 2N . The stator of the rotary electric machine according to claim 1.
The stator core is a stator of a rotary electric machine, which is formed by laminating a steel plate laminate formed by laminating a plurality of steel plates with each other in multiples of N so as to have different circumferential phases.

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