JP2006115578A - Dynamo-electric machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To constitute a dynamo-electric machine so that it can carry out the reduction of cogging torque in spite of simple constitution. <P>SOLUTION: In the dynamo-electric machine which axially bears an armature 1, which is constituted by stacking a plurality of core materials 3, where twelve pieces of teeth 3b are made, rotatably on a rotating shaft 1a and winding coils in the slots 4a made among teeth 3b, rotatably against a yoke 2 which is made in two poles, being equipped with a pair of permanent magnets 5, the first and second recesses 5b and 5c are made axially long at the internal perimeter of each permanent magnet 5 described above thereby so constituting it as to generate torque which is in reverse phase to that of cogging torque being generated between the end of a permanent magnet 5 and the armature 1, between the recesses 5b and 5c and the armature 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention belongs to the technical field of an armature of a rotating electrical machine that constitutes electrical components and the like mounted on a vehicle.

In general, in this type of rotating electric machine, an armature is formed by laminating a plurality of core materials having a plurality of teeth formed on the outer periphery on a rotating shaft and winding a coil in a long slot in the axial direction formed between the teeth. The armature's rotating shaft is rotatably supported by a yoke having an arc-shaped permanent magnet that forms at least a pair of magnetic poles.
By the way, in a rotating electrical machine such as an electric motor, it is a problem to reduce the cogging torque during rotation. One of the main causes of the cogging torque is the circumference of the permanent magnet arranged on the yoke side. It is known that the magnetic flux density of the teeth changes (magnetic resistance change) at the magnetic pole end, which is the direction end, and therefore cogging torque is generated at a predetermined order corresponding to the number of teeth. In order to cope with this, it has been proposed that when the core material is laminated, the coil groove formed in the slot-corresponding portion is displaced from the armature shaft, that is, in a skewed state. A proposal has been proposed in which a change in magnetic flux density generated between the magnet end and the teeth is relaxed. However, in this case, the effect of lowering the cogging cannot be obtained sufficiently, and problems still remain, and when skewed in this way, the characteristic deterioration and the winding property of the coil are reduced as the effective magnetic flux decreases. There is a problem that a problem of getting worse occurs. Therefore, both ends in the circumferential direction of the permanent magnet are made into a thin plate shape (eccentric shape) so that the facing distance between the magnet and the tooth at the portion is widened, thereby reducing the cogging torque. Has been advocated.

On the other hand, as a measure to reduce the cogging torque, in order to cancel out the cogging torque generated at the end of the magnet, a concave portion for generating torque having an opposite phase to the cogging torque is formed on the inner peripheral surface of the permanent magnet. There is something to do.
JP-A-3-45140

  In the prior art, in order to generate the same number of orders as the cogging torque, the recesses are formed at intervals similar to the slot forming angle intervals, and all the magnets are formed. ing. However, even in this case, the cogging torque is not yet sufficiently reduced, and in recent years when higher performance is required, there is a problem that the present invention intends to solve.

The present invention was created with the object of solving these problems in view of the above circumstances, and the invention of claim 1 is based on a core material having a plurality of teeth formed on the outer periphery thereof. An armature formed by laminating a plurality of coils and winding a coil in a slot formed between teeth is rotatably supported on a yoke having a pair of arc-shaped permanent magnets so as to form at least a pair of magnetic poles. In a rotating electrical machine, a long recess in the axial direction is formed on the inner peripheral surface of each permanent magnet so that the cogging torque generated between the end of the permanent magnet and the armature is offset in the circumferential direction of each slot. When the formation angle interval is θ, at least one permanent magnet has a circumferential groove width angle θw smaller than θ, and the circumferential groove center position is a circumferential center line of the permanent magnet. As a reference, go around A first concave portion located within an angle range of (θ / 2) on both sides of the first concave portion, and located on both sides in the circumferential direction of the first concave portion, and when the groove center position is a natural number n, the first concave portion At least a pair of second recesses are formed that are located within an angle range of (θ / 2) with reference to a position at an angle nθ from the groove center position.
And by doing in this way, the formation number of a recessed part can be decreased irrespective of the number of teeth, and cogging torque can be reduced efficiently.
According to a second aspect of the present invention, when the number of slots is S and the number of permanent magnet magnetic poles is P, the number obtained by dividing the least common multiple M of the number of slots S and the number of magnetic poles P by the number of slots S is 1 ( In the rotating electrical machine of M / S = 1), the first and second recesses are provided in at least one permanent magnet, and in this way, the first and second recesses formed in the permanent magnet The cogging torque can be reduced without providing all the permanent magnets.
According to a third aspect of the present invention, in the first aspect, when the number of slots is S and the number of magnetic poles of the permanent magnet is P or more, the least common multiple M of the number of slots S and the number of magnetic poles P is divided by the number of slots S. In the rotating electrical machine having the number of 2 (M / S = 2), the first and second recesses are provided at least on a pair of permanent magnets that are not opposed to each other. The cogging torque can be reduced without providing the first and second recesses to be formed in all the permanent magnets.
According to a fourth aspect of the present invention, in the first aspect, when the number of slots is S and the number of magnetic poles of the permanent magnet is P or more, the least common multiple M of the number of slots S and the number of magnetic poles P is divided by the number of slots S. In a rotating electrical machine having a number of 3 or more and less than the number of magnetic poles (3 ≦ M / S <P), the first and second recesses are provided at least in the respective permanent magnets that do not face each other. Thus, the cogging torque can be reduced without providing the first and second recesses formed in the permanent magnets in all the permanent magnets.

According to the invention of claim 1, the number of concave portions can be reduced and the cogging torque can be efficiently reduced.
According to the invention of claim 2, the cogging torque can be reduced without providing the first and second recesses formed in the permanent magnet in all the permanent magnets.
According to the invention of claim 3, the cogging torque can be reduced without providing the first and second recesses formed in the permanent magnets in all the permanent magnets.
According to the fourth aspect of the present invention, the cogging torque can be reduced without providing the first and second recesses formed in the permanent magnet in all the permanent magnets.

Next, an embodiment of the present invention will be described based on the drawings of FIGS.
In the drawings, reference numeral 1 denotes an armature (corresponding to the armature of the present invention) of an electric motor (rotating electric machine) constituting an electrical component mounted on a vehicle. The armature 1 is a rotating shaft (armature shaft) serving as a rotation center. ) The basic structure, such as both ends of 1a being rotatably supported by the bottomed cylindrical yoke 2, is as usual.

3 is a thin plate-shaped core material constituting the armature 1, and the core material 3 extends long in the circumferential direction on the outer periphery of the ring-shaped boss 3 a and on the distal end of the base that protrudes radially outward. A plurality of substantially T-shaped teeth 3b each having a protruding claw portion are formed in the circumferential direction. Here, the circumferential angle between adjacent teeth 3b (the formation interval angle of the teeth 3b) θ is determined by the number of teeth 3b to be formed, and when the number of teeth is N, the formation interval angle θ of the teeth 3b Is (360 / N) degrees.
Then, the armature core 4 is set to be configured by externally fitting the boss portions 3a of the plurality of core materials 3 to the armature shaft 1a in a non-rotating manner. Here, as shown in FIG. 1, the core material 3 according to the first embodiment is formed by twelve teeth 3 b in the circumferential direction, whereby the core material 3 is laminated. Twelve slots (coil grooves) 4a are formed long in the axial direction between adjacent teeth 3b on the outer periphery of the armature core 4 configured as described above. And it sets so that the armature 1 may be comprised by winding a coil (not shown) in these slots 4a. Both ends of each coil are connected to a commutator (not shown) that is integrally fitted to the armature shaft 1a, and set so that external power is supplied to the coil via the commutator. ing.

Now, a pair of arc-shaped permanent magnets 5 is fixed to the inner peripheral surface of the yoke 2 to constitute an electric motor having a two-pole permanent magnet.
Then, on the inner peripheral surfaces of the pair of permanent magnets 5, a first concave portion 5b having a concave groove shape that is long in the axial direction is formed at a substantially central portion in the circumferential direction of the permanent magnet 5. Here, the groove width angle θw1 in the circumferential direction of the first recess 5b is the formation interval angle θ of the teeth 3b (the formation interval angle of the slots 4a. In the present embodiment, twelve slots 4a (teeth 3b) is formed, and is set to be smaller (θw1 ≦ θ) than 360/12 = 30 degrees).

  The first recess 5b is provided to be located within an angle range of an angle α set in advance on both sides of the center line M in the circumferential direction with respect to the center line M in the circumferential direction of the permanent magnet 5. . Incidentally, the angle α may be an angle that is half of the formation interval angle θ of the teeth 3b, that is, within (θ / 2 = 15) degrees, and in the first embodiment, α = 0, that is, the first The groove center M1 of the recess 5b and the center line M of the permanent magnet 5 are provided at the same line.

In addition, on both sides in the circumferential direction of the first recess 5b of each permanent magnet 5, a second recess 5c having a long recess in the axial direction is formed. The groove width θw2 of the second recess 5c is formed. Is formed to have the same dimensions as the first recess 5b and is set to be smaller than the formation interval angle θ of the teeth 3b (θw2 = θw1 ≦ θ).
The formation position of the second recess 5c in the circumferential direction, that is, the groove center position M2 of the second recess 5c is the groove center M1 of the first recess 5b (in the case of the present embodiment, the circumferential direction of the permanent magnet). The position where the angle of the formation interval angle θ of the teeth 3b from the center line M) is set as the reference position MS, and the angle range of the angle α set in advance on both sides in the circumferential direction of the reference position MS As described above, the angle α may be half of the formation interval angle θ of the teeth 3b, that is, within an angle range of (θ / 2 = 15) degrees. In the embodiment, α is set to 4 ° and the position is shifted to the center line M side of the permanent magnet 5. Thus, the second recess 5c sets the groove center M2 such that the angle interval between the groove center M1 of the first recess 5b and the formation interval angle θ of the teeth 3b is different within the range of the angle α. As a result, the positional relationship in the circumferential direction of the teeth 3b facing the first recess 5b and the positional relationship in the circumferential direction of the teeth 3b facing the second recess 5c are not the same as each other, and the position is shifted. As a result, the first recess 5b generates a torque that is in reverse phase to the cogging torque generated at the end of the permanent magnet 5, and the second recess 5c The torque is set so as to generate a torque having a phase opposite to that of the cogging torque.

By the way, in the electric motor described above, that is, in the electric motor in which the pair of permanent magnets 5 are formed with the first recess 5b and the pair of second recesses 5c on both sides in the circumferential direction thereof, the armature core 4 is driven by driving the electric motor. , The cogging torque Tm generated between the tooth 3b and the end of the permanent magnet 5 is a torque with a rotation angle of 30 degrees as one cycle as shown by the phantom line in FIG. Cogging torque).
On the other hand, the torque (cogging torque) Tr generated between the teeth 3b of the armature core 4 and the first and second recesses 5b and 5c provided in the pair of permanent magnets 5 is shown by a thin line in FIG. Furthermore, it occurs in a state where the rotation angle is 30 degrees. Thus, the torque Tr generated between the first and second recesses 5b and 5c and each tooth 3b is opposite to the cogging torque Tm generated between the circumferential end of the permanent magnet 5 and each tooth 3b. The phase relationship is set so that the torque Tr generated by the first and second recesses 5b and 5c cancels the cogging torque Tm generated at the circumferential end of the permanent magnet 5. Is set to
As described above, the cogging torque Tm and the torque Tr cancel each other, so that when the electric motor including the armature 1 is driven to rotate, the cogging torque T indicated by the thick line in FIG. Accordingly, the cogging torque is set so as to be effectively reduced.

  The graph shown in FIG. 2A uses the electric motor according to the first embodiment and a permanent magnet having a uniform circumferential thickness in place of the permanent magnet 5 of the electric motor. The cogging torque values measured in the conventional electric motor EM1 and in the electric motor EM2 in the state where no recess is formed in the permanent magnet 5 of the electric motor of the first embodiment are shown, respectively. It was confirmed that the cogging torque was excellently reduced for the electric motor of the embodiment.

  Further, the graph shown in FIG. 2B is an electric motor including the electric motor of the first embodiment, the conventional electric motor EM1, and a permanent magnet having an inclined surface formed at the end in the circumferential direction. The cogging torque value and effective magnetic flux amount measured for each of the motors EM2 are values (ratio) when the cogging torque value and effective magnetic flux amount of the conventional electric motor EM1 are used as the reference (1). From this, it can be seen that the electric motor of the first embodiment is an electric motor having excellent performance in which the cogging torque is reduced and the reduction of the effective magnetic flux amount is suppressed.

  Here, the graph shown in FIG. 3 is an electric motor according to the first embodiment, an electric motor EM2 having a permanent magnet with an inclined surface formed at an end in a circumferential direction, and a permanent of the electric motor EM2. The cogging torque value measured about each of the electric motor EMS which formed only the 1st recessed part in the magnet is shown. According to FIG. 3, in the electric motor EMS in which only the first concave portion is formed, the top portion of the waveform of the cogging torque generated in the conventional electric motor EM <b> 2 is reduced, and the first and second concave portions 5 b. In the electric motor of the first embodiment in which 5c is formed, it can be confirmed that the bottom part of the waveform of the cogging torque that cannot be canceled out by the first recessed part 5b is canceled out. It was confirmed that the cogging torque can be further reduced by forming both the first recess 5b and the second recess 5c slightly out of phase with the first recess 5b.

  In the embodiment of the present invention configured as described above, the armature 1 is rotated by energizing the coils wound around the slots 4a of the armature core 4. At this time, the armature 1 and the permanent magnet are rotated. The cogging torque Tm generated between the magnetic pole ends of the first and second magnetic poles is located on the armature 1 and the first recess 5b formed on the inner peripheral surfaces of the pair of permanent magnets 5 and on both sides in the circumferential direction of the first recess 5b. The torque Tr generated between the pair of second recesses 5c cancels out, and the cogging torque is reduced. In addition to this, in addition to the first concave portion 5b generated between the armature 1 and the cogging torque generated between the armature 1 and the peripheral end portion of the permanent magnet 5, the first concave portion Second recesses 5c are formed on both sides in the circumferential direction of 5b, and the formation position in the circumferential direction of the second recesses 5c is defined as α (= θ / 2) ) Within the range of (). Thereby, as described above, the top of the cogging torque Tm generated between the end of the permanent magnet 5 and the armature 1 is canceled by the first recess 5b, and the skirt of the cogging torque Tm is canceled by the second recess 5c. As a result, the cogging torque T can be further reduced.

Of course, the present invention is not limited to the above embodiment, and the first and second recesses are formed based on the number of teeth constituting the rotating electrical machine and the number of permanent magnets provided on the yoke. The number of locations and the number of second recesses (multiple pairs) can be set as appropriate.
In other words, when the number of slots is S and the number of magnetic poles of the permanent magnet is P, the number of slots obtained by dividing the least common multiple M of the number of slots S and the number of magnetic poles P by the number of slots is 1 (M / S = 1). Thus, for example, in the rotating electrical machine having 12 slots and 2 magnetic poles as in the first embodiment, the least common multiple is 12, and the value obtained by dividing 12 by 12 slots is 1. In this electric motor, the state of the slot facing one magnetic pole is the same as that for the other magnetic pole. In such an electric motor, the first and second recesses are provided in at least one permanent magnet (magnetic pole). Thus, the cogging torque can be reduced.
The first and second recesses are formed at the same position as described in the first embodiment, so that the cogging torque is opposite to the cogging torque generated at the end of the permanent magnet. Torque can be generated.

As in the electric motor of the first embodiment, in the electric motor having 12 slots and 2 magnetic poles, as described above, the opposing state of the slot with respect to one magnetic pole is the same as that with respect to the other magnetic poles. For this reason, the first and second recesses 5b and 5c may be formed only in the N-pole permanent magnet 5 as in the electric motor 6 of the second embodiment shown in FIG. Even in this case, it was confirmed that the cogging torque was reduced. The armature 1 constituting the electric motor 6 of the second embodiment is the same as that of the first embodiment, and the description of the configuration is denoted by the same reference numerals as those of the first embodiment. It will be omitted.
Incidentally, when configured as in the second embodiment, it is necessary to balance the magnitude of the torque generated by the first and second recesses 5b and 5c with respect to the magnitude of the cogging torque due to the end of the permanent magnet 5. For this reason, it is necessary to form a deeper groove depth than that of the first embodiment.
In such a configuration, the first and second recesses 5b and 5c only need to be formed in one permanent magnet 5, so that not only the machining of the permanent magnet 5 is facilitated, but also the cost can be reduced. There are advantages.

The electric motors 7 and 8 of the third and fourth embodiments shown in FIGS. 5 (A) and 5 (B) are configured with 20 slots and 4 magnetic poles. The least common multiple of the number of slots and the number of magnetic poles is 20, and the numerical value obtained by dividing the least common multiple 20 by the number of slots 20 is “1” as in the electric motor of the first embodiment. In this case, the first and second recesses 9a and 9b are formed in any one of the four permanent magnets 9, that is, in the electric motor 7 in FIG. One N-pole permanent magnet 9 is formed with one first recess 9a and a pair of second recesses 9b on both sides in the circumferential direction of the first recess 9a according to the above-described formation position conditions. Even a thing can reduce cogging torque.
On the other hand, the electric motor 8 of the fourth embodiment shown in FIG. 5B has a configuration in which first and second recesses 9a and 9b are provided in each pole, that is, all the permanent magnets 10, respectively. Even in this case, the cogging torque can be reduced, but in this case, the groove depths of the recesses 9a and 9b can be made shallower than those in the third embodiment. Further, when the teeth facing each pole have the same positional relationship, the first and second recesses are formed in the pair of permanent magnets out of the two pairs of permanent magnets. Even in such a configuration, a reduction in cogging torque can be realized.

When the number of slots is S and the number of magnetic poles of the permanent magnet is P or more, the number obtained by dividing the least common multiple M of the number of slots S and the number of magnetic poles P by the number of slots S is 2 (M / S = 2). The electric motors 10 and 11 of the fifth and sixth embodiments shown in FIGS. 6A and 6B, for example, have 22 slots and 4 magnetic poles by the permanent magnet 12. In this case, the opposing state of the slot with respect to a pair of magnetic poles is the same as that with respect to the other pair of magnetic poles, and the opposing state of the slot with respect to a pair of N poles and S poles is different. . For this reason, a pair of permanent magnets that are not opposed to each other are formed with first and second recesses for generating a cogging torque having a phase opposite to that of the cogging torque generated at the end of the permanent magnet. The same number of torques as the torque can be generated and canceled out, and the cogging torque of the electric motor can be reduced.
In the electric motor 10 of FIG. 6A, the first concave portion 12a and the pair of second concave portions 12b are formed in each of the pair of permanent magnets 12 so as to satisfy the conditions of the formation position. In the electric motor 11 of 6 (B), the first and second recesses 12a and 12b are respectively formed on all four permanent magnets 12 in the same manner as in FIG. 6 (A). It was confirmed that the cogging torque can be reduced in both cases.

Incidentally, in the graph of FIG. 7 (A), the angle interval between the groove center position in the circumferential direction of the first recess and the groove center position of the second recess is an integral multiple of the tooth formation angle interval. The electric motor configured as described above, that is, the electric motor having the same positional relationship in the circumferential direction between the first and second recesses and the teeth facing the EMM, is referred to as EMM, and the electric motor EMM and the sixth A reduction rate of the cogging torque value measured with the electric motor 11 of the embodiment (shown in FIG. 6B) based on the cogging torque value of the conventional electric motor EM1 is shown. As is apparent from the graph, the reduction rate can be increased by not matching the formation positions of the first and second recesses with the formation angle interval of the teeth, and the cogging torque can be further reduced. It was confirmed that
Further, FIG. 7B is a graph in which whether or not there is a difference in the cogging torque reduction rate depending on the amount of misalignment angle with respect to the tooth formation angle interval for the formation positions of the first and second recesses. The figure is shown. According to the graph, it was confirmed that the reduction rate of the cogging torque can be increased and further reduction can be achieved by shifting the angle by a predetermined angle.

  When the number of slots is S and the number of magnetic poles of the permanent magnet is P or more, the number obtained by dividing the least common multiple M of the number of slots S and the number of magnetic poles P by the number of slots S is 3 or more and the number of magnetic poles Less than (3 ≦ M / S <P), for example, an electric motor having a slot number of 8 and a magnetic pole number of 6 (the number obtained by dividing the least common multiple M by the slot number S is 3), a slot number of 12, In a rotating electric machine such as an electric motor having 10 magnetic poles (the number obtained by dividing the least common multiple M by the number of slots S is 5), the armature semi-circular teeth and the yoke semi-circular permanent magnet are opposed to each other. As a result, by forming a recess in each of the magnetic poles that are not opposed to each other, it is possible to generate a torque of the same order as the cogging torque generated at the magnetic pole tip, thereby reducing the cogging torque as an electric motor. It is possible to play a.

  In addition, as a recessed part, what formed two or more pairs of 2nd recessed parts in the both sides of a 1st recessed part may be sufficient, and the formation position has the same arrangement | positioning conditions as said 1st embodiment in that case. By satisfy | filling, it forms so that the cogging torque by a recessed part may become an antiphase with respect to the cogging torque produced in the edge part of a permanent magnet.

1A and 1B are side sectional views of an electric motor and graphs showing measured values of cogging torque generated in the electric motor, respectively. FIGS. 2A and 2B are graphs showing measured values of cogging torque in the first embodiment and the conventional electric motor, cogging torque of the electric motor of the first embodiment with respect to the conventional product, and FIGS. It is a graph which shows the ratio of the amount of effective magnetic fluxes. It is a graph which shows the measured value of the cogging torque in 1st embodiment, the conventional product, and the electric motor in which one recessed part is formed. It is side surface sectional drawing of 2nd embodiment. 5A and 5B are side sectional views of the third and fourth embodiments, respectively. 6A and 6B are side cross-sectional views of the fifth and sixth embodiments, respectively. FIGS. 7A and 7B are graphs showing the cogging torque reduction rate in the sixth embodiment and the conventional electric motor, respectively, and the change in the cogging torque reduction rate depending on the positional deviation of the first and second recesses. FIG.

Explanation of symbols

1 Armature 1a Armature shaft 2 Yoke 3 Core material 3b Teeth 4 Armature core 4a Slot 5 Permanent magnet 5a Inclined surface 5b First recess 5c Second recess

Claims (4)

  A pair of arc-shaped armatures formed by laminating a plurality of core materials having a plurality of teeth on the outer periphery around a rotation shaft and winding a coil in a slot formed between the teeth to form at least a pair of magnetic poles. In a rotating electrical machine that is rotatably supported by a yoke having a permanent magnet, a long concave portion is formed in the inner peripheral surface of each permanent magnet in the axial direction between the end of the permanent magnet and the armature. In canceling the generated cogging torque, when the formation angle interval in the circumferential direction of each slot is θ, the groove width angle θw in the circumferential direction is smaller than θ in at least one permanent magnet, A groove center position is located on both sides of the circumferential direction of the permanent magnet, on the both sides of the circumferential direction of the first recess, and on the both sides of the circumferential direction of the first recess. The groove center position is n A rotating electrical machine in which at least a pair of second recesses are formed that are located within an angle range of (θ / 2) with reference to a position at an angle of nθ from the groove center position of the first recess. .   In claim 1, when the slot number is S and the permanent magnet magnetic pole number is P, the number obtained by dividing the least common multiple M of the slot number S and the magnetic pole number P by the slot number S is 1 (M / S = 1). In a rotating electrical machine, the first and second recesses are provided in at least one permanent magnet.   2. The number of slots obtained by dividing the least common multiple M of the number of slots S and the number of magnetic poles by the number of slots S is 2 (M / In the rotating electrical machine of S = 2), the first and second recesses are respectively provided in a pair of permanent magnets that are not opposed to each other.   In claim 1, when the number of slots is S, and the number of magnetic poles of the permanent magnet is P or more, the number obtained by dividing the least common multiple M of the number of slots S and the number of magnetic poles P by the number of slots S is 3 or more. In a rotating electrical machine having less than the number of magnetic poles (3 ≦ M / S <P), the first and second recesses are provided in each permanent magnet that is not opposed to each other.

Images