JP2018152960A - Rotating electric machine stator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stator of a rotary electric machine capable of reducing torque ripple. A stator of a rotating electric machine has 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 fastened to a housing with bolts. A stator core having a plurality of flanges provided with through-holes, and 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 such that the circumferential phase difference between the adjacent flanges in the circumferential direction deviates from a uniform arrangement over the entire circumference. [Selection diagram] Figure 1

Description

  The present invention relates to a stator for a rotating electrical machine.

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

Japanese Patent Laid-Open No. 2006-171636

  In the rotating electrical machine described above, the stator core is fixed to the housing by inserting a bolt into a through hole provided in the 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 rotating electrical 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 rotating electrical machine 1 in which the flanges 6 are provided on the outer circumferential surface of the stator yoke 4 at intervals of 60 degrees, the presence of the flanges 6 causes a magnetic imbalance, and the magnetic imbalances. Since the rotor 2 is periodically affected by the balance, the torque varies.

  Hereinafter, the principle of torque ripple generation in the rotating electrical 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. 4A is a conceptual diagram of a portion corresponding to the two magnetic pole portions of the rotor and the stator of the rotating electrical machine without the flange 6 as viewed from the axial direction, and FIG. 4B is a diagram of FIG. It is a graph which shows the torque change of 1 period corresponding to a structure. FIG. 5A is a conceptual diagram in which portions corresponding to the two magnetic pole portions of the rotor 2 and the stator 3 of the rotating electrical machine 1 shown in FIG. 3 are viewed from the axial direction, and FIG. It is a graph which shows the torque change of 1 period 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) during 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 poles) as shown in FIG. 4B. This torque ripple is a basic order and is an inevitable variation, but if there is a magnetic imbalance, torque ripple of that order occurs. The flange 6 shown in FIG. 3 is formed of an electromagnetic steel material that is 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. Causes equilibrium.

  Since the flanges 6 are provided at regular intervals of 60 degrees, as shown in FIG. 5A, the flanges 6 are positioned on a specific phase of the stator 3 (V phase in FIG. 5A). For this reason, the magnetic flux easily flows on the stator yoke 4 side of the specific phase, and the magnetic flux hardly flows on the stator yoke 4 side of the other two phases (the U phase and the W phase in FIG. 5A). As a result, a magnetic imbalance occurs. Thus, the torque fluctuates due to magnetic imbalance due to the flanges 6 provided at regular intervals. In the example shown in FIG. 3, the magnetic pole portion of the rotor 2 passes twice (N pole, S pole) with respect to each flange 6, and six flanges 6 are provided at intervals of 60 degrees. A torque ripple of the 12th order (= 360 degrees / 60 degrees × 2 magnetic pole portions) is generated. As a result, as shown in FIG. 5B, in addition to the basic order torque ripple shown in FIG. 4B, a torque ripple is generated by combining the 12th order torque ripple.

  Since the torque ripple described above is a main factor of the circular vibration of the rotor 2, if the torque ripple can be reduced, vibration and noise of the rotor 2 can be further suppressed. For this reason, in order to improve the quietness of a vehicle equipped with a rotating electrical machine, a reduction in torque ripple is required. Further, if the torque ripple can be reduced, the torque of the rotating electrical machine is improved.

  The objective of this invention is providing the stator of the rotary electric machine which can reduce a torque ripple.

In order to achieve the above object, the invention described in claim 1
An annular stator yoke (for example, a stator yoke 33 in an embodiment described later), a plurality of teeth (for example, teeth 34 in an embodiment described later) projecting from the stator yoke at an equal interval in the radial direction, A plurality of through holes (for example, through holes 37 in the embodiments described later) provided to protrude from the stator yoke to the other radial direction and fastened to a housing (for example, a housing 40 in the embodiments described later) by bolts. A stator core (e.g., stator core 31 in an embodiment described later) having a flange (e.g., flange 36 in an embodiment described later),
A rotating electrical machine (e.g., a coil (e.g., a coil 32 in an embodiment described later)) inserted into a slot (e.g., a slot 35 in an embodiment described later) formed between adjacent teeth. A stator (for example, a stator 30 in an embodiment described later) of a rotating electrical machine 10) in an embodiment described later,
The plurality of flanges arranged in the circumferential direction of the stator yoke is a stator of a rotating electrical machine in which circumferential phase differences between adjacent flanges in the circumferential direction are shifted from uniform arrangement over the entire circumference.

The invention according to claim 2 is the invention according to claim 1,
The circumferential phase difference of the flanges adjacent in the circumferential direction of the plurality of flanges has two values,
An arrangement of a flange having a first circumferential phase difference (for example, a circumferential phase difference θ1 in an embodiment described later) and a second circumferential phase difference ( For example, the arrangement of the flanges having the circumferential phase difference θ2) in the embodiments described later is alternately performed over the entire circumference.

The invention according to claim 3 is the invention according to claim 2,
When the number of the plurality of flanges provided over the entire circumference of the other outer periphery in the radial direction of the stator yoke is 2N,
The first circumferential phase difference is “360 / 8N × 5” degrees, and the second circumferential phase difference is “360 / 8N × 3” degrees.

The invention according to claim 4 is the invention according to claim 3,
The stator core is formed by rolling a steel plate laminate formed by laminating a plurality of steel plates, multiple times of the N times so as to have different circumferential phases.

  According to the first aspect of the present invention, since the positions of the flanges in the circumferential direction are not uniform, torque ripples caused by magnetic imbalance caused by the flanges can be canceled out by torque ripples by different flanges. As a result, torque ripple of the rotating electrical machine can be reduced.

  According to the second aspect of the present invention, there is a difference 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. For this reason, the torque ripple of a rotary electric machine can be reduced.

  According to the invention of claim 3, since the torque ripple by the two flanges having the circumferential phase difference of “360 / 8N × 5” degree or “360 / 8N × 3” degree has a phase difference of about 180 degrees, Torque ripples caused by magnetic imbalance caused by the flange cancel each other. For this reason, the reduction rate of torque ripple can be maximized.

  According to the fourth aspect of the present invention, it is possible to carry out the roll-over that can realize the reduction of the distortion of the stator core and the homogenization of the magnetic characteristics of the stator core with a single type of steel plate.

It is radial direction sectional drawing of the rotary electric machine of one Embodiment. It is the graph which shows the conceptual diagram which looked at the part corresponding to three magnetic pole parts of the rotor of the rotary electric machine shown in FIG. 1 from the axial direction, and the torque change of 1 period. It is radial direction sectional drawing of the rotary electric machine with which the flange was provided at equal intervals. (A) is the conceptual diagram which looked at the part corresponding to two magnetic pole parts of the rotor of a rotary electric machine without a flange, and a stator from the axial direction, (b) is 1 period corresponding to the structure of (a). It is a graph which shows a torque change. (A) is the conceptual diagram which looked at the part corresponding to two magnetic pole parts of the rotor of a rotary electric machine shown in FIG. 3, and a stator from the axial direction, (b) is 1 corresponding to the structure of (a). 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 are viewed in the direction of the reference numerals.

  FIG. 1 is a radial cross-sectional view of a rotating electrical machine according to an embodiment. A rotating electrical machine 10 shown in FIG. 1 includes a rotor 20, a stator 30 that is opposed to the outer side in the radial direction of the rotor 20 via a slight gap, and a housing 40 that accommodates and fixes the stator 30 therein. The rotating electrical machine 10 is configured such that the rotor 20 rotates by energizing the coil 32 wound around the teeth 34 of the stator 30.

  The rotor 20 includes a rotating shaft 21 that is 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. It is a rotor of a magnet-embedded rotating electrical 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 electromagnetic steel sheet has a shaft insertion hole 26 through which the rotating shaft 21 is inserted at the center thereof, and a plurality of a pair of magnet insertion holes 23, 23 are formed at predetermined intervals in the circumferential direction on the outer periphery thereof. Yes. Further, the pair of magnet insertion holes 23, 23 have a substantially V shape that expands toward the outer peripheral surface that is the surface of the rotor core 22 that faces the stator 30.

  The electromagnetic steel plate is made of a magnetic material, and two permanent magnets 24, 24 inserted into the pair of magnet insertion holes 23, 23 constitute a single magnetic pole portion 25. That is, two permanent magnets 24, 24 having the same magnetization direction are inserted into a pair of magnet insertion holes 23, 23 constituting one magnetic pole portion 25, and permanent magnets are inserted so that the magnetic poles are alternately reversed in the circumferential direction. The For example, as shown in FIG. 1, if the outer peripheral side of the magnetic pole part 25a is an N pole, the adjacent magnetic pole part 25b is configured by inserting a permanent magnet 24 into the magnet insertion hole 23 so that the outer peripheral side becomes an S pole. Has been.

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

  The stator core 31 is configured by rolling (rotational buildup) so that a plurality of steel plate laminates have different circumferential phases. The steel plate laminate is formed by laminating a plurality of steel plates such as electromagnetic steel plates. The stacked thickness may be the same or different. In addition, the steel plate which comprises a steel plate laminated body is provided with the insulating layer which is not illustrated in the one surface or both surfaces so that the steel plates adjacent in an axial direction may not conduct | electrically_connect.

  Each steel plate includes an annular stator yoke 33, a plurality of teeth 34 protruding radially inward from the stator yoke 33 at equal intervals, slots 35 formed at equal intervals in the circumferential direction between adjacent teeth 34, a stator It is a plate-like member that protrudes radially outward from the yoke 33 and has a flange 36 provided with a through-hole 27, and is formed by pressing a magnetic steel sheet. In the present embodiment, 2N pieces (where N is a natural number of 2 or more), that is, an even number of 4 or more flanges 36 are provided over the entire circumference of the stator yoke 33. The example shown in FIG. 1 is for 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 tooth 34 is inserted into the slot 35.

  Further, when a plurality of steel plate laminates are laminated, a through hole 37 penetrating in the axial direction is 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) through the through hole 37 and fastening it to the housing 40. Note that the flange 36 has a pair of inclined surfaces 36d and 36e that approach a virtual straight line IL that connects the center O of the rotating electrical machine 10 and the through hole 37 as viewed in the axial direction as it goes 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 equally spaced, and the circumferential phase difference between adjacent flanges 36 in the circumferential direction is the entire circumference of the stator yoke 33. Are arranged out of uniform arrangement. That is, the circumferential phase difference of the flanges 36 adjacent in the circumferential direction among the six flanges 36 has two values of 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 adjacent flanges 36 is an angle formed by two virtual straight lines IL connecting the center O of the rotating electrical 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 difference between the flanges 36 adjacent in the circumferential direction is not equalized, but is advanced by a predetermined value θ from the circumferential phase difference θ0 (60 degrees = 360 degrees / 2N). The circumferential direction phase difference θ1 (75 degrees = 360 degrees / 8N × 5) and the circumferential direction phase difference θ2 (45 degrees = 360 degrees / 8N × 3) delayed by the predetermined value θ are alternately arranged in an even number. (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 flange 36 adjacent 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−the circumferential phase difference θ2 when 2N flanges 36 are evenly arranged, P is the number of pole pairs of the rotor, and constant 2 is the torque ripple order is 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 101b caused by the torque ripple 101a caused by the flange 36a and 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 approximately 180 degrees between the two torque ripples 101a and 101b, the two torque ripples 101a and 101b cancel each other. For this reason, 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 because of the phase difference has the same meaning.

  Thus, in this 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 flange 36 adjacent in the circumferential direction, and both torque ripples are synthesized. And cancel each other. As a result, torque ripple caused by the flange 36 included in the output torque of the rotating electrical 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 are alternately arranged over the entire circumference of the stator yoke 33. Has been done. For this reason, when rolling a plurality of steel sheet laminates, the rolling is carried out “360 / (θ1 + θ2)” times or multiples thereof for each θ1 + θ2. Therefore, in the present embodiment, the transposition that can realize the reduction of the distortion of the stator core 31 and the homogenization of the magnetic characteristics can be performed by a single type of steel plate.

  In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably. 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 “× 3” 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”. A configuration of “degree / 12N × 7” degrees (= 50 degrees) may be used. However, in this case, since the phase difference between the torque ripples caused by the flanges 36 adjacent in the circumferential direction is not 180 degrees, the reduction rate of the torque ripple is lower than that in the above embodiment.

  If the number of flanges 36 is reduced to three and evenly arranged, the torque ripple will be reduced by the number of flanges, but the number of fastenings between the stator core 31 and the housing 40 will be reduced. descend.

  Moreover, although the magnet insertion hole 23 is made into a substantially V shape by a pair, it is not restricted to a pair as a structure of a magnetic pole, One or three or more may be sufficient, and linear arrangement | positioning other than V shape etc. may be sufficient.

DESCRIPTION OF SYMBOLS 10 Rotating electrical machine 20 Rotor 21 Rotating shaft 22 Rotor core 23 Magnet insertion hole 24 Permanent magnet 25, 25a, 25b Magnetic pole part 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 (4)

An annular stator yoke, a plurality of teeth projecting from the stator yoke in one radial direction at equal intervals, a plurality of teeth projecting from the stator yoke in the other radial direction, and through holes for fastening to the housing by bolts A stator core having a flange;
A coil inserted into a slot formed between adjacent teeth, and a stator of a rotating electrical machine,
The plurality of flanges arranged in the circumferential direction of the stator yoke is a stator for a rotating electrical machine in which circumferential phase differences between adjacent flanges in the circumferential direction are shifted from uniform arrangement over the entire circumference. A stator for a rotating electrical machine according to claim 1,
The circumferential phase difference of the flanges adjacent in the circumferential direction of 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 were alternately performed over the entire circumference. A stator for rotating electrical machines. A stator for a rotating electrical machine according to claim 2,
When the number of the plurality of flanges provided over the entire circumference of the other outer periphery in the radial direction of the stator yoke is 2N,
The stator of the rotating electrical machine, wherein the first circumferential phase difference is “360 / 8N × 5” degrees and the second circumferential phase difference is “360 / 8N × 3” degrees. A stator for a rotating electrical machine according to claim 3,
The stator core is a stator of a rotating electrical machine in which a steel sheet laminate formed by laminating a plurality of steel sheets is rolled up multiple times of N so as to have different circumferential phases.

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