JP2013099193A - Electric rotary machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric rotary machine enabling a rotational drive with high quality and high performance, and with less vibration and noise, by decreasing a torque ripple and a cogging torque.SOLUTION: An electric rotary machine 10 comprises a stator 11 including a plurality of teeth 15 facing a rotor 12, and a plurality of slots 18 being spaces where a coil is wound around the teeth. In the electric rotary machine 10, a pair of permanent magnets 16 applying a magnetic force to the teeth are embedded in the rotor to form a V-shape, and thereby the rotor in the stator is rotationally driven by a reluctance torque and a magnet torque. Adjustment grooves 21 each having a groove depth Rt of 20-40% of a face distance Xg of a clearance G and a teeth width Ts are formed in an outer circumferential face 12a of the rotor at positions where a displacement angle θ1 with respect to a d axis is equal to 30°, so that respective magnetic flux densities of the teeth relatively moving smoothly vary.

Description

  The present invention relates to an electric rotating machine, and more particularly, to an electric rotating machine that realizes high-quality rotation driving.

  Electric rotating machines mounted on various devices are required to have characteristics corresponding to the mounted devices. For example, they are mounted on a hybrid electric vehicle with an internal combustion engine as a driving source, or as a single driving source. In the case of a drive motor mounted on an electric vehicle (Electric Vehicle), it is required to have a wide variable speed characteristic at the same time as generating a large torque in a low rotation range.

  As an electric rotating machine having such characteristics, it is effective to adopt a structure that can effectively use reluctance torque together with magnet torque, so that it becomes a V shape that opens toward the outer peripheral surface side, It has been proposed to adopt an IPM (Interior Permanent Magnet) structure in which a permanent magnet such as a neodymium magnet having a strong magnetic force is embedded in a rotor (for example, Patent Document 1).

  In an electric rotating machine that employs this IPM structure, a reluctance torque can be effectively utilized by embedding a permanent magnet in the rotor so as to be V-shaped and securing a q-axis magnetic path. From this, the ratio of the reluctance torque in this electric rotating machine becomes larger than the magnet torque, and the salient pole of the inductance ratio (Lq / Ld) of the q-axis and d-axis in the rotor in which the permanent magnet is embedded in the V-shape. The ratio is also increased, and spatial harmonics are easily superimposed on the magnetic flux waveform. The d-axis is the direction of the magnetic flux created by the magnetic pole, that is, the central axis between the V-shaped permanent magnets, and the q-axis is an adjacent magnetic pole (permanent magnet) that is electrically and magnetically orthogonal to the d-axis. It becomes the central axis between.

For this reason, in such an electric rotating machine, a torque ripple (torque) that is a fluctuation range of torque is used.
ripple) increases. This increase in torque ripple causes an increase in vibration and electromagnetic noise of the electric rotating machine. Among these, the electromagnetic noise has a relatively higher frequency band than the noise caused by the drive of the internal combustion engine, and the electric rotating machine is installed. It is preferable to reduce the noise as much as possible because the sound is uncomfortable for the vehicle occupant.

  In addition, the electric rotating machine is required to be driven with high efficiency in order to reduce power consumption and efficiently generate a desired driving force. It becomes a factor of decline.

  In particular, hybrid vehicles and electric vehicles are required to have an electric rotating machine that is capable of high energy density output through weight reduction and miniaturization in response to the recent demand for improved energy efficiency (fuel consumption) as well as restrictions on mounting space. For example, it is necessary to realize high-efficiency driving in an area that is regularly used when driving in an urban area after starting, for reducing judder that is abnormal vibration and smooth acceleration performance, It is effective to suppress the cogging torque caused by the attractive force of the permanent magnet together with the torque ripple.

  As such an electric rotating machine (motor), as the output density per unit volume is increased, electromagnetic noise increases due to the generation of torque ripple and cogging torque, and the efficiency tends to deteriorate. It is extremely difficult to achieve both efficiency improvement, electromagnetic noise reduction, low torque ripple, and low cogging torque, but the demand is also great.

  As a means for realizing reduction of this kind of electromagnetic noise, torque ripple, and cogging torque, the rotor is divided in the axial direction so that the permanent magnets are twisted in the rotational direction (circular rotation direction). It has been proposed to apply skew (for example, Patent Document 2).

  However, in a skewed electric rotating machine, the assembly man-hours increase and the production cost increases, and since the adjacent permanent magnets are assembled in a state where there is a step, the boundary surface of the step The magnetization rate in the vicinity deteriorates, and the magnetic flux density as a permanent magnet decreases. As a result, the output torque provided for the electric rotating machine is reduced.

  For this reason, in this type of electric rotating machine, various devices have been devised to reduce electromagnetic noise and the like without causing skew, and the cross-sectional shape of the outer peripheral surface of the rotor rotating in the stator is changed. It has been proposed that the gap (air gap) between the outer peripheral surface of the rotor and the inner peripheral surface of the stator is widened at the crossing position with the q axis, for example, by making it petal-like (for example, patents) Literature 1, 3, 4).

  However, in the electric rotating machine as described in Patent Documents 1, 3, and 4, the magnetic resistance is increased by increasing the air gap in a wide range around the q axis serving as the excitation axis. As the salient pole ratio and torque decrease, the efficiency deteriorates.

  In addition, in this type of electric rotating machine, magnetic flux wraps around the permanent magnets in order to suppress torque ripple and cogging torque while solving the problem of torque reduction without increasing the magnetic resistance. It has been proposed to devise the shape of the flux barrier to be restricted (for example, Patent Documents 5 and 6).

  However, in the electric rotating machine as described in Patent Documents 5 and 6, in order to form a flux barrier having a specific shape, a bridge portion that connects and supports the outer peripheral surface side of the rotor with a permanent magnet interposed therebetween. There is a possibility that a so-called burst phenomenon may occur in which the strength cannot be ensured and the bridge portion is broken by a centrifugal force during high-speed rotation and breaks.

  Further, in this type of electric rotating machine, it is proposed to form a groove extending in the axial direction on the outer peripheral surface of the rotor in order to suppress torque ripple and cogging torque (for example, Patent Documents 7 to 11). .

  However, in Patent Documents 7 to 11, it does not correspond to all the conditions of the electric rotating machine that adopts the three-phase IPM motor structure, and how to determine the groove forming position. Important formation conditions such as whether the groove width should be good and what is necessary are unknown. For this reason, it cannot be applied to other structures. For example, the optimum conditions can be set according to various conditions such as permanent magnet installation conditions, the tip width of a tooth portion described later in the stator, and the opening width of the slot. Can not.

JP 2008-99418 A JP 2006-304546 A JP 2000-197292 A JP 2007-312591 A JP 2002-223538 A JP 2009-77525 A Japanese Patent Laid-Open No. 2004-328956 JP 2008-206308 A JP 2008-220053 A JP 2008-31316 A JP 2011-142735 A

  Accordingly, an object of the present invention is to provide an electric rotating machine that can reduce torque ripple, cogging torque, and the like, and can perform high-quality and high-efficiency rotational driving with less vibration and noise.

  A first aspect of the invention relating to an electric rotating machine that solves the above problems includes a rotor that integrally rotates a rotating shaft of a shaft center, and a stator that rotatably accommodates the rotor, and the fixed The child wraps around the teeth portion, a plurality of teeth portions extending toward the outer peripheral surface that rotates around the rotor and facing the inner peripheral surface side to the outer peripheral surface, and a coil for inputting driving power. A plurality of slots formed between the teeth portions in a space, and the rotor is embedded with a plurality of permanent magnets so as to exert a magnetic force against the opposing surface of the teeth portions, A reluctance torque generated when magnetic flux passes through the teeth portion, the back surface of the teeth portion, and the rotor, and an attractive force or a repulsive force generated between the permanent magnets and generated when the coil is energized. An electric rotating machine that rotates and drives the rotor in the stator by net torque, wherein one set of the permanent magnets on the rotor side corresponds to one set of the slots on the stator side. When the one set of permanent magnet side is one magnetic pole, the magnetic flux density for each of the tooth portions forming the one set of slots corresponding to the one magnetic pole smoothly changes from the center of the one magnetic pole to both sides ( It is characterized in that the formation region of the magnetic path of the magnetic flux in the rotor is adjusted so as to be continuous.

  According to a second aspect of the invention relating to the electric rotating machine that solves the above problem, in addition to the specific matter of the first aspect, an outer peripheral surface facing the teeth portion of the rotor, and the one set of permanent magnets The shape of the magnetic path forming region of the magnetic flux between the outer peripheral surface side of the rotor is formed so as to smoothly continue outward from the center of the one magnetic pole. is there.

  According to a third aspect of the invention relating to the electric rotating machine that solves the above problem, in addition to the specific matter of the second aspect, the magnetic flux density of each tooth portion is smoothly changed from the center of the one magnetic pole to both sides. The shape of the magnetic path formation region of the magnetic flux is parallel to the teeth portion at a width within the facing width of the teeth portion on the outer peripheral surface of the rotor facing the teeth portion at equal positions on both sides with respect to the center of the one magnetic pole. It is characterized by having an adjustment groove formed to become.

  In a fourth aspect of the invention relating to the electric rotating machine that solves the above problem, in addition to the specific matter of the third aspect, the rotor side is opened in a V shape toward the outer peripheral surface side. A pair of the permanent magnets is embedded to form the one magnetic pole, and the stator side is an electric rotating machine having six sets of the one set of slots on the stator side. The adjustment groove having a width opposite to the teeth portion is formed at a position with an electrical angle of 30 degrees in the reverse direction, and the adjustment groove is 0.2 ≦ groove depth / opposite surface of the tooth portion and the outer peripheral surface. It is formed in the shape which satisfy | fills distance ≦ 0.4.

  In a fifth aspect of the invention relating to the electric rotating machine that solves the above problem, in addition to any one of the first to fourth specific items, a magnetic flux wraps around the outer end side of the one set of permanent magnets. When the flux barrier to be restricted is formed, the one magnetic pole is constituted including the outer end portion of the flux barrier.

  According to a sixth aspect of the invention relating to the electric rotating machine that solves the above-described problem, in addition to the specific matter of the fifth aspect, the magnetic flux density of each tooth portion is smoothly changed from the center of the one magnetic pole to both sides. As the shape of the magnetic path formation region of the magnetic flux, the outer wall surface of the flux barrier that forms the magnetic path formation region of the magnetic flux between the outer peripheral surface of the rotor and the extended surface of the outer surface of the permanent magnet It is characterized by being formed in a curved shape that curves inward of the rotor.

  The seventh aspect of the invention relating to the electric rotating machine that solves the above-described problem is such that, in addition to the specific matter of the sixth aspect, the rotor side opens in a V shape toward the outer peripheral surface side. A pair of the permanent magnets are embedded to form the one magnetic pole, and the stator side is an electric rotating machine having six sets of the one set of slots, and the outer wall surface of the flux barrier. Is a curved surface within the range of R6 to R10, and the included angle between the extended surface of the outer surface of the permanent magnet and the tangent of the outer wall surface at an adjacent location of the permanent magnet is within a range of 0 ° to 4 °. It is formed so that it may become.

  Thus, according to said 1st aspect of this invention, when the magnetic flux produced | generated by supplying with electricity to the coil by the side of a stator passes the magnetic path continuous on the rotor side which faces from a teeth part. The magnetic flux density changes smoothly for each magnetic pole in accordance with the magnetic path formation region on the rotor side. Therefore, the interphase voltage applied to each phase coil can be distorted and a sudden change in magnetic flux can be suppressed, and the cogging torque can be reduced together with the torque ripple of the torque fluctuation that occurs during the rotation of the rotor. A low-quality and high-quality rotational drive can be realized, and at the same time, it can be rotationally driven with high efficiency with little loss.

  According to the second aspect of the present invention, the magnetic flux forming region between the outer peripheral surface of the rotor facing the teeth portion on the stator side and the one magnetic pole permanent magnet has the one magnetic pole. The magnetic flux density of each tooth portion at the time of relative movement is adjusted so as to continue smoothly from the center of one magnetic pole toward the outside, so that the magnetic flux density flowing from the tooth portion to the outer peripheral surface of the rotor can be adjusted. Therefore, the magnetic flux waveform for each tooth portion can be smoothly continued to reduce the cogging torque together with the torque ripple generated during the rotation of the rotor, and a high-quality rotation drive with less loss along with vibration and noise can be realized. .

  According to the third aspect of the present invention, the adjustment grooves that are parallel to each other within the facing width of the teeth portion are formed on both sides of the center of one magnetic pole on the outer peripheral surface of the rotor facing the teeth portion on the stator side. The magnetic flux density for each tooth portion at the time of relative movement of one magnetic pole is adjusted so as to continue smoothly. That is, the adjustment groove is formed so that the formation region of the magnetic path of the magnetic flux through the gap between the outer peripheral surface facing the teeth portion of the rotor is smoothly continued outward from the center of one magnetic pole, The magnetic flux density flowing from the teeth portion into the outer peripheral surface of the rotor can be adjusted. Therefore, the magnetic flux waveform for each tooth portion can be smoothly continued to reduce the cogging torque together with the torque ripple generated during the rotation of the rotor, and a high-quality rotation drive with less loss along with vibration and noise can be realized. .

  According to the fourth aspect of the present invention, in the case where one magnetic pole of a pair of V-shaped permanent magnets corresponds to one set of six slots, the groove depth / tooth portion opposes the outer peripheral surface. An adjustment groove formed so that the inter-surface distance is 0.2 to 0.4 is formed at a position where the forward / reverse electrical angle is 30 degrees with respect to the center of one magnetic pole. Therefore, torque ripple and cogging torque can be reduced, and high-quality rotation drive with less loss as well as vibration and noise can be realized.

  According to the fifth aspect of the present invention, the magnetic flux of the magnetic flux on the outer peripheral surface of the rotor facing the teeth portion including (considering) the flux barrier on the outer end side of the permanent magnet in one magnetic pole. The path formation region is formed so as to continue smoothly from the center of one magnetic pole toward the outside. Therefore, it is possible to reduce the cogging torque together with the torque ripple while effectively utilizing the magnetic flux, and to realize a high-quality rotation drive with less loss along with vibration and noise.

  According to the sixth aspect of the present invention, the outer wall surface of the flux barrier that forms the magnetic flux magnetic path between the outer peripheral surface of the rotor facing the teeth portion on the stator side is the permanent magnet. It is formed in a curved shape that curves inward of the rotor from the extended surface of the outer surface. That is, the magnetic flux path formation region (magnetic flux passage shape and passage area) between the outer peripheral wall surface of the flux barrier on the outer peripheral surface side facing the teeth portion of the rotor is smoothly continuous outward. The magnetic flux density flowing from the teeth portion into the outer peripheral surface of the rotor can be adjusted. Therefore, the magnetic flux waveform for each tooth portion can be smoothly continued to reduce the cogging torque together with the torque ripple generated during the rotation of the rotor, and a high-quality rotation drive with less loss along with vibration and noise can be realized. .

  According to the seventh aspect of the present invention, in the case where one magnetic pole of a pair of V-shaped permanent magnets corresponds to one set of six slots, the tangent to the extended surface from the outer surface of the permanent magnet is obtained. The outer wall surface of the flux barrier is formed so as to be curved surfaces of R6 to R10 that are continuous within a range of 0 ° to 4 °. Therefore, torque ripple and cogging torque can be reduced, and high-quality rotation drive with less loss as well as vibration and noise can be realized.

It is a figure which shows one Embodiment of the electric rotary machine which concerns on this invention, and is a top view which shows the basic structure. It is a top view which shows the generation | occurrence | production situation of the magnetic flux generation | occurrence | production when there is no magnetic pole in the rotor side. It is a graph explaining solution of the subject of the present invention. It is a partially expanded plan view explaining the solution of the problem of the present invention. It is a partially expanded plan view which shows the structural conditions of one place of the one embodiment. It is a graph explaining condition determination of the composition. It is a graph explaining condition determination different from FIG. 6 of the structure. It is a graph explaining condition determination different from FIG. 6 of the structure. It is a partially expanded plan view which shows the structural conditions of the location different from FIG. 6 of the one embodiment. It is a partially expanded conceptual diagram which shows generation | occurrence | production of the magnetic flux in the attention location by the structure. It is a partially expanded conceptual diagram which shows generation | occurrence | production of the magnetic flux in the attention location of the conventional structure without the structure. It is a graph explaining the effect by the presence or absence of application of the one embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1-12 is a figure which shows one Embodiment of the electric rotary machine which concerns on this invention.

  In FIG. 1, an electric rotating machine (motor) 10 includes a stator (stator) 11 formed in a substantially cylindrical shape, and a rotating shaft 13 that is rotatably housed in the stator 11 and coincides with an axis. For example, in a hybrid vehicle or an electric vehicle, it has a performance suitable for mounting as a drive source similar to an internal combustion engine or in a wheel wheel. ing.

The stator 11 includes a plurality of stator teeth extending in the normal direction of the axis so that the outer peripheral surface 12a of the rotor 12 faces the inner peripheral surface 15a via a gap G (see FIG. 5). 15 is formed. The stator teeth 15 have three-phase windings that form a coil (a U-phase coil _CU is shown in FIG. 4) that generates magnetic flux for rotationally driving the rotor 12 that is housed face-to-face. It is attached.

  The rotor 12 is manufactured to have an IPM (Interior Permanent Magnet) structure in which a pair of permanent magnets 16 are embedded as one magnetic pole so as to be V-shaped to open toward the outer peripheral surface 12a. The rotor 12 includes a space 17a in which a corner portion 16a of a flat plate-like permanent magnet 16 extending in the front and back direction of the drawing is fitted in a facing state and accommodated in a stationary state, and both sides in the width direction of the permanent magnet 16 A V-shaped space 17 that forms a space 17b (hereinafter also referred to as a flux barrier 17b) that functions as a flux barrier that restricts the wraparound of the magnetic flux is formed so as to face the outer peripheral surface 12a. A center bridge 20 that connects and supports the permanent magnets 16 is formed between the V-shaped spaces 17 so that the permanent magnets 16 can be positioned and held against centrifugal force during high-speed rotation.

  In this electric rotating machine 10, the space between the stator teeth 15 constitutes a slot 18 for forming a coil by winding it through a winding, and six stator teeth are provided on each of the eight sets of permanent magnets 16. It is constructed so that 15 slots face each other, in other words, 6 slots 18 correspond to one magnetic pole formed on the pair of permanent magnets 16 side. That is, the electric rotating machine 10 is wound with 8 poles (4 pole pairs), 48 slots, single-phase distributed winding 5 pitches, with the N and S poles of the permanent magnet 16 alternately arranged for each adjacent magnetic pole. It is made to a wired three-phase IPM motor. In addition, the display of the N pole and the S pole in the figure does not exist on the surface of the member, but is shown for explanation.

  Thus, the electric rotating machine 10 attracts the permanent magnet 16 when the coil in the slot 18 of the stator 11 is energized and the magnetic flux is passed through the rotor 12 facing from the stator teeth 15. In addition to the magnet torque caused by the repulsive force, it can be rotationally driven by a total torque including the reluctance torque that attempts to minimize the magnetic path through which the magnetic flux passes, and the rotating shaft 13 that rotates integrally with the rotor 12. It is possible to output the electrical energy energized and input as mechanical energy.

  Here, as shown in FIG. 2, the electric rotating machine 10 is equally arranged in the rotor 12 from the stator 11 for each of a plurality of stator teeth 15 corresponding to a pair of permanent magnets 16 constituting one magnetic pole. A winding coil is distributedly wound in the slot 18 so as to form a magnetic path, and the permanent magnet 16 is accommodated along this magnetic path, in other words, so as not to prevent the formation of magnetic flux. A V-shaped space 17 is formed. Note that the stator 11 and the rotor 12 are screwed by using a bolt hole 19 or the like by superposing thin sheets of electromagnetic steel plate material such as silicon steel in the axial direction so as to have a thickness corresponding to a desired output torque. It is produced by.

  By the way, in the IPM structure in which the permanent magnet 16 is embedded in the rotor 12 in the rotor 12 as in the electric rotating machine 10, the direction of the magnetic flux generated by the magnetic pole, that is, the central axis between the V-shaped permanent magnets 16 is the d axis. Further, the central axis between the permanent magnets 16 between the adjacent magnetic poles, which are electrically and magnetically orthogonal to the d axis, is defined as the q axis.

The electric rotating machine 10 has harmonics superimposed at the timings α and β in one cycle, for example, as shown in the no-load U-phase to V-phase line voltage waveform shown in FIG. The distortion of the line voltage increases according to the magnitude of the superimposed harmonic. Timings α and β in one cycle of the harmonics in the line voltage waveform are for the U-phase voltage wound around the slot 18 on the stator 11 side, as shown in FIG. 4, from the relationship between the phase voltage and the line voltage. the coil C _U, symmetrical position B to center the d axis when combined one magnetic pole of the rotor 12 side (16 side pair of permanent magnets), corresponds the stator teeth 15 and D, this period alpha, By reducing the phase voltage waveform component in β, distortion of the line voltage can be suppressed.

  For this reason, the electric rotating machine 10 suppresses the harmonic component by increasing the magnetic resistance to the magnetic flux interlinked with the corresponding stator teeth 15 of the harmonic component superposition times α and β. As shown, a concave adjustment groove 21 for adjusting a gap G between the inner peripheral surface 15a of the stator teeth 15 and the outer peripheral surface 12a of the rotor 12 is formed. As will be described later, the adjusting groove 21 can be formed on the outer peripheral surface 12a of the rotor 12 facing the inner peripheral surface 15a of the stator teeth 15 to increase the magnetic resistance by lowering the magnetic permeability. In addition, the harmonic component to be superimposed is suppressed, and the line voltage waveform is brought close to a sine wave to reduce the distortion of the line voltage. That is, the adjustment groove 21 has a magnetic path of the magnetic flux so that the magnetic flux density of the magnetic flux passing from the stator tooth 15 on the stator 11 side to the rotor 12 side changes smoothly and continuously within one cycle corresponding to one magnetic pole. The magnetic resistance in the formation region is adjusted.

  The adjustment groove 21 is determined by performing an electromagnetic field analysis by the finite element method to determine the optimum position and shape to be formed on the outer peripheral surface 12a of the rotor 12, and the formation position of the deepest portion 21b sandwiched between the inclined surfaces 21a. And the optimum condition of the depth is determined and formed.

  Specifically, the adjustment groove 21 has, for example, an edge interval of the inclined surface 21a that matches the groove depth Rt from the outer peripheral surface 12a to the deepest portion 21a of the rotor 12 and the facing width of the inner peripheral surface 15a of the stator teeth 15. The formation position is determined by performing electromagnetic field analysis by the finite element method with the groove width Ts being constant, and symmetrical about the d-axis (center line between the pair of permanent magnets 16) of one magnetic pole of the rotor 12. The displacement angle θ1 of the amount of deviation in the forward / reverse direction of the position of the deepest portion 21b facing the stator teeth 15 at positions B and D is used as a parameter. Here, the adjusting groove 21 has a groove width Ts that matches the facing width of the inner peripheral surface 15a of the stator teeth 15. However, this condition is suitable, but not limited to this, and the above-described symmetrical position B As long as it is within the range facing the inner peripheral surface 15a of the stator teeth 15 located at D, the width may be reduced as appropriate in accordance with the adjustment of the magnetic flux formation region.

In the electromagnetic field analysis by this finite element method, the line voltage THD (Total Harmonic Distortion :) represents the cogging torque reduction rate due to the attractive force due to the magnetic force of the pair of permanent magnets 16 and the harmonic content in the line voltage. When the rate of increase of the harmonic distortion factor is derived, the result shown in the graph of FIG. 6 is obtained. From the graph of FIG. 6, the displacement angle θ1 in the forward / reverse direction with respect to the d-axis can satisfactorily suppress the cogging torque and the line voltage THD under the following condition 1 and within the range of the following condition 2 It can be seen that the following condition 3 is the optimum value. By satisfying such a condition, the adjustment groove 21 has an effect on the magnetic permeability between the inner peripheral surface 15a of the stator teeth 15 at the symmetrical positions B and D with the d axis as the center and the outer peripheral surface 12a facing this. The line voltage waveform can be made closer to a sine wave by lowering the magnetic resistance (increasing the magnetic resistance). The reduction rate of the cogging torque and the increase rate of the line voltage THD are calculated on the basis of the cogging torque and the line voltage THD in the rotor 12 in which the adjustment groove 21 is not formed on the outer peripheral surface 12a.
Condition 1: 28 ° ≦ | θ1 (electrical angle) | ≦ 32 °
Condition 2: 29 ° ≦ | θ1 (electrical angle) | ≦ 31 °
Condition 3: θ1 = ± 30 °

  Further, the adjustment groove 21 changes the groove depth Rt while leaving the groove width Ts as it is, and the gap interval (opposing surface) of the gap G between the outer peripheral surface 12a of the rotor 12 and the inner peripheral surface 15a of the stator teeth 15 is changed. The groove depth Rt is determined by performing electromagnetic field analysis by the finite element method using the ratio δ of the groove depth Rt to the inter-distance distance Xg as a parameter.

In this electromagnetic field analysis by the finite element method, when the load is not imposed on the electric rotating machine 10, for example, when the reduction rate of the cogging torque and the increase rate of the line voltage THD in the case of downhill sliding are derived, The result shown in the graph of FIG. 7 can be obtained. Further, when the torque reduction rate and the torque ripple that is the fluctuation range of the torque are derived together with the rate of increase of the line voltage THD in the torque regular area required when driving in an urban area after starting, as shown in the graph of FIG. Results can be obtained. From the graph of FIG. 7 at the time of no load, it can be seen that the ratio δ = 40% is the optimum condition, and from the graph of FIG. 8 in the torque normal range, the ratio δ = 20% is the optimum condition. I understand that there is. Considering both of these, it is preferable that the ratio δ of the groove depth Rt with respect to the gap Xg of the air gap G be within the range of about the following condition 4, and by satisfying such a condition, Torque ripple and line voltage THD can be suppressed satisfactorily while keeping the reduction rate small, and the inner peripheral surface 15a of the stator teeth 15 at the symmetrical positions B and D centering on the d axis and the outer peripheral surface 12a facing this By effectively reducing the magnetic permeability between them (increasing the magnetic resistance), the line voltage waveform can be made closer to a sine wave. The torque reduction rate and the torque ripple reduction rate are based on the cogging torque and the line voltage THD in the rotor 12 in which the adjustment groove 21 is not formed on the outer peripheral surface 12a, similarly to the increase rate of the line voltage THD. To calculate.
Condition 4: 20% ≦ δ (δ = Rt / Xg) ≦ 40%

  Further, in this electric rotating machine 10, one magnetic pole of the permanent magnet 16 including the pair of flux barriers 17b on the rotor 12 side rotates relative to the stator 11 side, so that one magnetic pole is provided for each of the plurality of stator teeth 15. Are repeatedly facing each other, and the rotor 12 is driven to rotate when magnetic flux passes between the stator teeth 15 and the rotor 12. At this time, in the rotor 12, the outer peripheral surface 12a of the rotor 12 and the outer peripheral surface 12a side of the flux barrier 17b before and after the rotation direction of one magnetic pole facing the inner peripheral surface 15a of the stator tooth 15 of the stator 11 The formation state of the magnetic flux passing through the region between the fillet portion (outer wall surface) 17bw located at the position changes. From this, on the outer peripheral surface 12a side of the rotor 12, as shown in FIG. 9, at least the fillet portion 17bw of the flux barrier 17b is formed in a curved shape. As a result, the magnetic flux formation region between the outer peripheral surface 12a of the rotor 12 and the fillet portion 17bw of the flux barrier 17b changes smoothly and continuously toward the outside of one magnetic pole. Thus, the switching of the stator teeth 15 that face the outer peripheral surface 12a of the rotor 12 on the inner peripheral surface 15a side can be smoothly continued for each magnetic pole, and the magnetic flux formed in the stator teeth 15 can be changed. It is possible to prevent the density (strength) from changing suddenly and to make torque change smoothly continuous. In addition, sufficient strength to support the permanent magnet 16 in the rotor 12 can be obtained (without loss).

  Specifically, the curved shape of the fillet portion 17bw of the flux barrier 17b at one magnetic pole on the rotor 12 side may be set according to the magnitude of torque required for a hybrid vehicle or an electric vehicle. For example, the rotor 12 As the magnetic flux passage area in the region between the outer peripheral surface 12a and the outer peripheral surface 12a increases, the magnetic flux leakage to the outside of one magnetic pole of the rotor 12 increases.

  For example, the electric rotating machine 10 is a neodymium magnet (Nd-Fe-) as an example of a hybrid vehicle used at a reduction ratio of 7.0 to 10.0, equivalent to a vehicle equipped with a 660 to 1200 cc gasoline engine. A case will be described in which the permanent magnet 16 is manufactured by adopting B) and a structure sufficient to generate a torque necessary for traveling when the trunk is used with four passengers is described.

  In this case, as shown in FIG. 9, the thickness Tf of the thinnest portion between the outer peripheral surface 12a of the rotor 12 and the fillet portion 17bw of the flux barrier 17b, and the thickness Tf are rotated. The flux barrier 17b in the vicinity of the intersection M between the extension surface 17aw of the opposing wall surface of the accommodation space 17a of the permanent magnet 16 in the V-shaped space 17 and the arc surface Raf using the arc surface Raf attached to the outer peripheral surface 12a of the child 12. The curvature shape Rf of the fillet portion 17bw is set to the curvature radii R6 to R10. In addition, the fillet portion 17bw of the flux barrier 17b has an included angle θ2 of 0 ° to a flux barrier opening straight line L1 that is a tangent to the extended surface 17aw of the accommodation space 17a of the V-shaped space 17 at a location adjacent to the permanent magnet 16. It is determined so as to be within the range of 4 °. 9 represents the inclination angle of the extension surface 17aw (permanent magnet 16) of the accommodation space 17a of the V-shaped space 17 with respect to the d axis, and this inclination angle θ3 can also suppress torque ripple and the like. Just decide. Here, the radius of curvature at the intersection position M will be described. However, the present invention is not limited to this. The entire fillet portion 17bw of the flux barrier 17b is simply smooth from the extended surface 17aw of the accommodation space 17a of the V-shaped space 17. Needless to say, the radii of curvature R6 to R10 may be formed continuously.

  As described above, in the rotor 12, as shown in FIG. 10, the fillet portion 17bw of the flux barrier 17b in one magnetic pole is formed in a curved shape, so that the magnetic flux passing through the region between the outer peripheral surface 12a and the stator teeth 15 Thus, the magnetic flux passing through the stator teeth 15 can be prevented from changing suddenly and generating a large cogging torque.

  Specifically, as shown in FIG. 11, the fillet portion 17 bw of the flux barrier 17 b is curved while the included angle between the extension surface 17 aw of the accommodation space 17 a of the V-shaped space 17 and the flux barrier opening straight line L <b> 1 is θ2 = 0 °. In the case of a conventional shape that bends without becoming a shape, the change in magnetic flux density is abrupt. As is clear when attention is paid to the edge of the stator tooth 15 indicated by a broken line in the figure, about 1/4 of the flux barrier 17b is the stator tooth as shown in timings T1 and T2 in FIGS. 11 (a) to 11 (b). The magnetic flux φ hardly passes through the surface facing 15, and the magnetic flux φ starts to increase rapidly only when about half of the flux barrier 17 b faces the stator teeth 15 at the timing T <b> 3 in FIG. 11C. As a result, the cogging torque becomes large.

  On the other hand, in this electric rotating machine 10, as shown in FIG. 10, the fillet portion 17 bw of the flux barrier 17 b is formed in a curved shape that satisfies the above conditions, so that the magnetic flux density is relative to the stator teeth 15. It changes according to. As is clear when attention is paid to the edge portion of the stator teeth 15 indicated by broken lines in the figure, as shown from the timing T1 in FIG. 10A to the timing T2 in FIG. The magnetic flux φ has already begun to increase even when facing the stator teeth 15, and further, as indicated by timing T <b> 3 in FIG. 10C, the magnetic flux φ increases as the stator teeth 15 face more than about half of the flux barrier 17 b. A smooth torque that increases smoothly and does not become cogging torque can be generated and output.

  Therefore, in this electric rotating machine 10, as shown in FIG. 12, the adjustment groove 21 is not formed on the outer peripheral surface 12a of the rotor 12, and the fillet portion 17bw of the flux barrier 17b is not formed in a curved shape. In contrast to the fact that a large cogging torque is generated as shown by waveform A in the figure, the cogging torque as shown by waveform B in the figure can be obtained simply by forming the adjustment groove 21 on the outer peripheral surface 12a of the rotor 12. Can be reduced. Further, in addition to the adjustment groove 21, the fillet portion 17bw of the flux barrier 17b is formed in a curved shape under the above conditions, so that the generation of a small cogging torque can be suppressed as shown by the waveform C in the figure.

  As described above, in the present embodiment, the groove width Ts coincides with the width of the stator teeth 15 facing the inner peripheral surface 15a at the position of the outer peripheral surface 12a of the rotor 12 where the displacement angle θ1 = 30 ° with respect to the d-axis. Then, the adjustment groove 21 having the groove depth Rt is formed such that the ratio of the gap G between the outer peripheral surface 12a and the inner peripheral surface 15a to the interval Xg is 20% to 40%. Further, the fillet portion 17bw of the flux barrier 17b is formed in a curved shape having a curvature radius R6 to R10. As a result, an IPM structure motor capable of smoothly continuing the magnetic flux density for each stator tooth 15 formed when one magnetic pole moves relative to each other and generating a high-quality torque with a smooth magnetic flux waveform. be able to. Therefore, the electric rotating machine 10 can be rotated with high quality with less vibration and noise, and can be driven to rotate with high efficiency with less loss.

  Here, in this embodiment, a case where a structure in which the permanent magnet 16 is V-shaped and embedded in the rotor 12 is employed will be described as an example. However, the present invention is not limited to this. The present invention can also be applied to the case of a flat plate arrangement embedded in a state facing a flat plate shape with respect to the outer peripheral surface 12a, and similar effects can be obtained.

  In addition, an electric rotating machine 10 having an 8-pole 48-slot motor configuration is taken as an example, and an angle corresponding to one cycle (360 °) of one magnetic pole pair will be described as an electrical angle. However, the present invention is not limited to this. The present invention can also be applied to other motor structures in which 6 slots correspond to the magnetic poles. For example, the present invention can also be applied to a motor structure having 6 poles, 36 slots, 4 poles, 24 slots, and 10 poles and 60 slots.

  The scope of the present invention is not limited to the illustrated and described exemplary embodiments, but includes all embodiments that provide the same effects as those intended by the present invention. Further, the scope of the invention is not limited to the combinations of features of the invention defined by the claims, but may be defined by any desired combination of particular features among all the disclosed features. .

  Although one embodiment of the present invention has been described so far, it is needless to say that the present invention is not limited to the above-described embodiment, and may be implemented in various forms within the scope of the technical idea.

DESCRIPTION OF SYMBOLS 10 Electric rotating machine 11 Stator 12 Rotor 12a Outer peripheral surface 13 Rotating shaft 15 Stator teeth 15a Inner peripheral surface 16 Permanent magnet 16a Corner part 17 V-shaped space 17b Flux barrier 17bw Fillet part 18 Slot 20 Center bridge 21 Adjustment groove 21a Slope 21a Deepest part G Air gap Rt Groove depth Ts Groove width Xg Gap spacing θ1 Displacement angle θ2 Nipping angle φ Magnetic flux

Claims (7)

A rotor that integrally rotates the rotation shaft of the shaft center, and a stator that rotatably accommodates the rotor,
The stator includes a plurality of teeth portions that extend toward the outer peripheral surface that rotates around the rotor and faces the outer peripheral surface to the inner peripheral surface side, and a coil that inputs driving power to the teeth portion. A plurality of slots formed between the teeth portions in a space for winding,
In the rotor, a plurality of permanent magnets are embedded so as to exert a magnetic force against the opposing surface of the teeth portion,
Magnets of attraction force or repulsive force generated between the reluctance torque generated by the magnetic flux passing through the teeth portion, the back side of the teeth portion, and the rotor, and the permanent magnet, which are generated when the coil is energized. An electric rotating machine that rotationally drives the rotor in the stator by torque;
When one set of the permanent magnets on the rotor side corresponds to one set of the slots on the stator side, and the one set of permanent magnet side is one magnetic pole, it corresponds to the one magnetic pole. Adjusting the formation region of the magnetic path of the magnetic flux in the rotor so that the magnetic flux density of each tooth portion forming the set of slots smoothly changes from the center of the magnetic pole to both sides. Electric rotating machine.   The shape of the magnetic path formation region of the magnetic flux between the outer peripheral surface facing the teeth portion of the rotor and the outer peripheral surface side of the rotor of the set of permanent magnets is outside the center of the one magnetic pole. The electric rotating machine according to claim 1, wherein the electric rotating machine is formed to be smoothly continuous toward the direction. As the shape of the magnetic path formation region of the magnetic flux that the magnetic flux density for each tooth portion smoothly changes from the center of the one magnetic pole to both sides,
An adjustment groove formed on the outer peripheral surface of the rotor that faces the teeth portion at equal positions on both sides with respect to the center of the one magnetic pole so as to be parallel to the teeth portion with a width within the facing width of the teeth portion. The electric rotating machine according to claim 2, wherein the electric rotating machine is provided. On the rotor side, the one magnetic pole is configured by embedding the pair of permanent magnets so as to open in a V shape toward the outer peripheral surface side,
The stator side is an electric rotating machine in which the one set of slots is composed of six,
The adjustment groove of the facing width of the teeth portion is formed at a position of an electrical angle of 30 degrees in the forward and reverse direction with respect to the one magnetic pole center,
4. The electric rotation according to claim 3, wherein the adjustment groove is formed in a shape satisfying 0.2 ≦ groove depth / distance between the opposing surfaces of the tooth portion and the outer peripheral surface ≦ 0.4. Machine.   In the case where a flux barrier that restricts the wraparound of magnetic flux is formed on the outer end side of the set of permanent magnets, the one magnetic pole is configured including the outer end portion of the flux barrier. The electric rotating machine according to any one of claims 1 to 4. As the shape of the magnetic path formation region of the magnetic flux that the magnetic flux density for each tooth portion smoothly changes from the center of the one magnetic pole to both sides,
The outer wall surface of the flux barrier that forms a magnetic path formation region of the magnetic flux between the outer peripheral surface of the rotor and a curved shape that curves inward of the rotor from an extended surface of the outer surface of the permanent magnet. The electric rotating machine according to claim 5, wherein the electric rotating machine is formed. On the rotor side, the one magnetic pole is configured by embedding the pair of permanent magnets so as to open in a V shape toward the outer peripheral surface side,
The stator side is an electric rotating machine in which the one set of slots is composed of six,
The outer wall surface of the flux barrier is a curved surface within the range of R6 to R10,
The sandwiched angle between the extended surface of the outer surface of the permanent magnet and the tangent of the outer wall surface at an adjacent location of the permanent magnet is formed to be within a range of 0 ° to 4 °. Item 7. The electric rotating machine according to item 6.

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