JP2014117043A - Motor - Google Patents

Abstract

Cogging torque fluctuations are reduced.
A stator core of a motor is formed by stacking all-around cores in which arc-shaped divided cores are connected in an annular shape, and the all-around cores are stacked so that positions in the circumferential direction of the connecting portions of the split cores are different from each other. , The number of different circumferential positions St is
T is the number of teeth of the all-around core, P is the number of magnetic poles of the magnet, D is the number of divided cores,
L1 = (the least common multiple of P and D)
A = 360 ° × L1 / T
M = (remainder when A is divided by 360 °)
L2 = (the least common multiple of 360 ° and M)
If
St = n × L2 / M (n is an integer).
[Selection] Figure 6

Description

  The present invention relates to a motor having a stator core and a rotor.

  Some motor stators are configured by combining arc-shaped split cores in which the stator core is divided into a plurality of parts in order to increase the utilization rate of steel plates. Moreover, when producing the above arc-shaped division | segmentation cores, the utilization factor of a board | plate material can be raised by bending in a circular arc shape after punching a linear member from a board | plate material.

  In a stator core that uses a split core obtained by bending a linear member into an arc as described above, a plurality of split cores are combined to form a ring-shaped core of the first layer, from the second layer to the nth layer. In regard to, a technique is known in which the position is shifted by a predetermined angle from the position of the lower divided core (see, for example, Patent Document 1).

JP 2005-143164 A

  When a split core is produced by bending a straight punched member into an arc shape, a springback force is generated at the bent portion, and it is difficult to accurately maintain the radius of curvature of the arc. Therefore, the dimensional accuracy of the stator core after the split cores are combined tends to be lowered. Specifically, for example, the radius of the stator core (distance from the rotation center of the motor) increases in the vicinity of the connecting portion of the split core, while the radius of the stator core decreases in the portion between the connecting portions. Thus, when the radius of the stator core varies depending on the circumferential position, the cogging torque fluctuates due to the difference in the radius, causing problems such as increased torque pulsation and increased vibration and noise.

  When the cores of each layer are stacked with a predetermined angle shifted as in Patent Document 1, the position of the connecting portion of the stator core is dispersed, but the fluctuation of the cogging torque due to the difference in radius as described above. Is not necessarily reduced. In addition, the number of man-hours for manufacturing increases as the number of times the core is shifted by a predetermined angle increases.

  In view of this point, the present invention has an object of reducing fluctuations in cogging torque in a motor having a stator core formed by combining arc-shaped divided cores.

The first invention is
A stator core in which a plurality of arc-shaped split cores are connected in an annular shape and a circumferential core is laminated;
A motor having a rotor holding a magnet,
Each of the split cores is formed by curving a linear split core in which a plurality of teeth are linearly connected in an arc shape,
The circumferential core is laminated so that the circumferential positions of the connecting portions of the split cores are arranged at a plurality of different circumferential positions,
The number of different circumferential positions St is set as follows. That is,
T is the number of teeth of the all-around core, P is the number of magnetic poles of the magnet, D is the number of divided cores,
L1 = (the least common multiple of P and D)
A = 360 ° × L1 / T
M = (remainder when A is divided by 360 °)
L2 = (the least common multiple of 360 ° and M)
If
St = n × L2 / M (n is an integer).

  As a result, the fluctuation component of the cogging torque caused by the difference in the radii of the all-around core is canceled out, so that the cogging torque is reduced.

The second invention is
A motor according to a first invention,
The number St of the circumferential positions different from each other is set to be smaller than the number of teeth included in one divided core.

  Thereby, since the number (type) of the circumferential position of the connecting portion can be reduced, it is possible to reduce the man-hour when laminating the entire circumference core and simplify the process.

The third invention is
Any one of the first invention and the second invention,
The angle formed by the circumferential positions of the connecting portions of the divided cores adjacent to each other in the circumferential direction is an integral multiple of 2 or more of (360 ° / number of teeth T of the entire circumferential core).

The fourth invention is:
Any one of the first to third inventions,
There are at least two kinds of angles formed by the circumferential positions of the connecting portions of the divided cores adjacent to each other in the circumferential direction.

The fifth invention is:
There is a symmetry axis in which the position of the teeth is line symmetric, and there is a symmetry axis in which the circumferential position of the connecting portion of the split core is not line symmetric.

  As described above, even when the angle formed by the circumferential positions of the connecting portions is larger than or not equal to the teeth pitch angle, or when there is no symmetry, the number of the different circumferential positions St If the condition is satisfied, the cogging torque is reduced.

The sixth invention is:
A motor according to any one of the first to fifth aspects,
Each of the linear divided cores is formed by punching from the plate member in such a manner that the teeth face each other in opposite directions, and the direction of the teeth with respect to the plate member is set on the linear divided core. A discriminating section that can be discriminated is provided.

  As a result, it is possible to easily increase the utilization factor of the plate member, and it is easy to reliably reduce the influence of uneven thickness due to uneven thickness of the plate member by making the orientation and combination of the split cores appropriate. Can be.

The seventh invention
Any one of the first to sixth inventions,
The stator core is provided between the inner peripheral wall and the outer peripheral wall in an insulator having a cylindrical inner peripheral wall and an outer peripheral wall, or inside the outer peripheral wall in the insulator having a cylindrical outer peripheral wall. And

  Thereby, it is possible to fix each circumferential core to each other without caulking or welding.

  In the present invention, the fluctuation of cogging torque can be reduced in a motor having a stator core formed by combining arc-shaped divided cores.

It is a top view which shows the shape of the linear division | segmentation core 101 punched out from the steel plate. It is a top view which shows the shape of the division | segmentation core 101 curved in circular arc shape. It is a top view which shows the 1 layer of perimeter core 201 combined in the annular | circular shape. It is a top view which shows typically the laminated | stacked perimeter cores 201A-201C. It is a graph which shows the example by which the fluctuation | variation of cogging torque is canceled. FIG. 6 is a plan view illustrating a configuration of a stator core according to a second embodiment. It is a top view which shows the example of the punching pattern of the steel plate 401. FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each of the following embodiments, components having functions similar to those of the other embodiments are denoted by the same reference numerals and description thereof is omitted.

Embodiment 1
As shown in FIG. 1, the split core 101 constituting the stator according to the motor of Embodiment 1 has a shape in which a plurality of (three in this embodiment) teeth 102 are connected by a yoke 103. Yes. Here, as shown in the figure, the shape in which the yoke portion 103 extends substantially linearly indicates the shape in which the split core 101 is punched from the steel plate. For example, one or a plurality of such punched steel plates are used. After the sheets are laminated, they are bent by being bent at the V-shaped cutout 104 formed in the yoke portion 103 to form an arc as shown in FIG. At both end portions of each divided core 101, a connecting convex portion 105 having a tip portion swelled in a trapezoidal shape and a connecting concave portion 106 having a deep portion expanded in a trapezoidal shape are formed.

  Four split cores 101 as described above are combined as shown in FIG. 3 to form an annular circumferential core 201. That is, the connecting convex portion 105 or the connecting concave portion 106 of each divided core 101 is engaged with the connecting concave portion 106 or the connecting convex portion 105 of the other divided core 101 to form the connecting portion 107, and the all-around core 201 is formed. The

  As shown schematically in FIG. 4, the all-round core 201 formed as described above has three first to third all-around cores 201 </ b> A to 201 </ b> C shifted from each other by 30 ° in the circumferential direction. That is, for example, the stator core assembly 301 is configured by stacking three stages in an arrangement in which the angles formed by the connecting portions 107 are 30 ° with each other. Here, when the first to third all-around cores 201A to 201C are bent in an arc shape, for example, the radius of curvature tends to increase due to the springback. In this case, as exaggeratedly depicted in the drawing, the radius of the entire circumference core 201 (distance from the rotation center of the motor) is increased in the portion of the connecting portion 107, while the portion between the two connecting portions 107 is entirely increased. The radius of the circumferential core 201 is reduced. However, the fluctuation component of the cogging torque caused by such a difference in radius (the fluctuation component caused by the divided core in the cogging torque) is canceled as described in detail later.

  The stator core assembly 301 is fitted, for example, between the inner peripheral wall and the outer peripheral wall in an insulator having a cylindrical inner peripheral wall and an outer peripheral wall (not shown), or inside the outer peripheral wall in an insulator having a cylindrical outer peripheral wall. Or after being resin-molded, the winding is wound into a stator. Further, on the inner periphery of the stator, for example, a rotor is rotatably mounted with four magnets held and having eight magnetic poles to constitute a motor.

  Next, the reason why the fluctuation component of the cogging torque caused by the difference in the radius of the all-around core 201 is canceled in the motor configured as described above will be described.

  For example, when the all-around core 201 is configured by combining four divided cores 101 (number of divisions D = 4) and the number of magnetic poles P of the rotor magnet is 8 = poles, the first all-around core 201A in cogging torque is used. For example, as shown in FIG. 5, the fluctuation component generated by the fluctuation of the radius of the rotor fluctuates at a period in which the rotor rotates 45 °. In addition, since the second circumferential core 201B is laminated with being shifted from the first circumferential core 201A by 30 ° in the circumferential direction, the fluctuation component caused by the variation of the radius is also different from that of the first circumferential core 201A. Fluctuates by 30 °. Similarly, the fluctuation component caused by the fluctuation of the deformation of the third all-around core 201C fluctuates by 60 °. Therefore, if the waveform of the fluctuation component caused by the fluctuation of the radius of the first to third all-round cores 201A to 201C in the cogging torque is a sine wave waveform as shown in FIG. 5, for example, these fluctuation components cancel each other. As a result, the amount of variation in synthesis is certainly zero. Even when the waveform of the fluctuation component is not a sine wave waveform, these are dispersed and canceled out, so that the cogging torque generated by the fluctuation of the radius of the all-around core 201 can be greatly reduced.

  Next, conditions for reducing the cogging torque generated by the variation in the radius of the all-around core 201 as described above will be described.

First,
Where T is the number of teeth of the all-around core, P is the number of magnetic poles of the magnet, and D is the number of divided cores.
In the cogging torque, the fluctuation component caused by the fluctuation of the radius of the all-around core 201 is as follows:
L1 = (the least common multiple of P and D)
It fluctuates by the number of times represented by. Assuming that the phase of one cycle of this fluctuation is 360 °, the phase change when the entire circumference core 201 is shifted by one teeth pitch angle is
A = 360 ° × L1 / T
It is represented by there,
M = (remainder when A is divided by 360 °)
L2 = (the least common multiple of 360 ° and M)
If
St = n × L2 / M (n is an integer)
When the number of positions in the circumferential direction at the connecting portion 107 is set to be St, the variation in the radius of the all-around core 201 in the cogging torque is performed as in the case shown in FIG. The resulting fluctuation component is dispersed and offset, and the fluctuation amount of the cogging torque is reduced.

  Specifically, for example, examples of St for various T, P, and D (when n = 1) are as follows (Table 1).

  Here, examples A1 to A3 shown in the table show examples in which the value of St is equal to the number of teeth per one divided core 101. That is, in this case, any connecting portion 107 is located between any adjacent tooth portions 102.

  On the other hand, examples B1 to B6 shown in the table show examples in which the value of St is smaller than the number of teeth per one divided core 101. In this case, the fluctuation component caused by the fluctuation of the radius of the all-around core 201 in the cogging torque is reduced, and the number (type) of the circumferential position of the connecting portion 107 can be reduced, so that the all-around core The man-hour when laminating 201 can be reduced and the process can be simplified.

  Here, in Reference Examples C1 to C3 shown in the table, St is indefinite. In this case, if the all-around core 201 is shifted by one tooth pitch angle, the fluctuation waveform of the cogging torque becomes the same at any position, so that the fluctuation amount is not offset and cannot be reduced.

<< Embodiment 2 >>
In the case of Example B6 in the above (Table 1), that is, as shown in FIG.
Number of teeth of all-around core T = 48
Number of magnetic poles P = 8
Number of divisions D = 4
An example of a specific configuration in this case will be described.

  In this example, since St = 6, for example, the entire circumference is six steps or an integral multiple of the number of steps so that the connecting portion 107 is located at six circumferential positions P1 to P6 shown in FIG. By stacking the cores 201 while shifting the cores 201, it is possible to reduce the fluctuation component caused by the fluctuation of the radius of the all-around core 201 in the cogging torque. In such an arrangement, the angle formed by the circumferential positions P1 to P6 is 7.5 °, whereas the angle formed by the circumferential positions P6 and P1 is 22.5 °. There will be different kinds of angles. Further, for example, the tooth portion 102 is arranged line-symmetrically with respect to the diameter passing through the circumferential position P1, whereas the connecting portion 107 is not line-symmetric. That is, even if there is such a difference in angle or asymmetry, if the number St of circumferential positions in the connecting portion 107 is set as described above, the fluctuation component caused by the fluctuation of the radius of the entire circumferential core 201 Can be reduced.

  Here, when creating the split core 101 for configuring the entire circumferential core 201 as described above, although not particularly limited, for example, as shown in FIG. 7, straight lines in which the teeth portions 102 face each other in opposite directions. It is also possible to punch the steel plate 401 in such an arrangement that the split cores 101 are in pairs. Thereby, the utilization factor of the steel plate 401 can be easily increased. Further, in this case, the split core 101 punched in the arrangement as shown in FIG. 7 has teeth portions T1B and T2B, T2A and T3A, T3B and T4B, and T4A and T1A, as shown in FIG. By connecting so that it may fit, the influence of the nonuniform thickness by the uneven thickness of the steel plate 401, etc. can be reduced. Further, in order to facilitate the determination of the arrangement in the punching of the split cores 101, a determination unit such as a predetermined minute hole or notch may be formed in each split core 101.

《Other matters》
In the above example, the example is shown in which the circumferential cores 201 are stacked while being shifted in units of one tooth pitch angle. However, the present invention is not limited thereto, and the stacking is performed by shifting in units of integer multiples of two or more teeth pitch angles. However, the fluctuation component caused by the fluctuation of the radius of the all-around core 201 in the cogging torque is reduced. However, the case where the teeth pitch angle is shifted by an angle that is a multiple of the number of teeth per divided core 101 (and an integer multiple thereof) is excluded. In this case, the position of the connecting portion 107 is the same, and this is the same as not shifting the entire circumference core 201.

  Further, in the above specific example, the example in which the peripheral cores 201 are shifted and stacked by the number of steps of the value of St when n = 1 is shown, but the present invention is not limited thereto, and even when n = 2 or more, cogging is still performed. The fluctuation component caused by the fluctuation of the radius of the all-around core 201 in the torque is reduced.

  Further, the entire circumferential core 201 having the same circumferential position of the connecting portion 107 is not limited to being provided with only one layer, but may be provided with being divided into a plurality of layers.

  In addition, it is not essential that the stator core assembly 301 is fitted into the insulator or resin-molded as described above. However, in the case of resin molding or the like as described above, the circumferential cores 201 are not necessarily fixed to each other by caulking or welding. You don't have to.

  In the above example, the inner rotor type motor in which the rotor is provided in the stator has been described. However, the same laminated structure can be applied to the stator in the outer rotor type motor.

  As described above, the present invention is useful as a motor having a stator core and a rotor, a manufacturing method thereof, and the like.

DESCRIPTION OF SYMBOLS 101 Divided core 102 Teeth part 103 Yoke part 104 Notch 105 Connection convex part 106 Connection recessed part 107 Connection part 201 Peripheral core 201A 1st perimeter core 201B 2nd perimeter core 201C 3rd perimeter core 301 Stator core assembly 401 Steel plate

Claims (7)

A stator core in which a plurality of arc-shaped split cores are connected in an annular shape and a circumferential core is laminated;
A motor having a rotor holding a magnet,
Each of the split cores is formed by curving a linear split core in which a plurality of teeth are linearly connected in an arc shape,
The circumferential core is laminated so that the circumferential positions of the connecting portions of the split cores are arranged at a plurality of different circumferential positions,
The number St of the circumferential positions different from each other is set as follows.
T is the number of teeth of the all-around core, P is the number of magnetic poles of the magnet, D is the number of divided cores,
L1 = (the least common multiple of P and D)
A = 360 ° × L1 / T
M = (remainder when A is divided by 360 °)
L2 = (the least common multiple of 360 ° and M)
If
St = n × L2 / M (n is an integer). The motor of claim 1,
The motor characterized in that the number St of the circumferential positions different from each other is set smaller than the number of teeth included in one divided core. A motor according to any one of claims 1 and 2,
A motor characterized in that an angle formed by circumferential positions of connecting portions of the divided cores adjacent to each other in the circumferential direction is an integer multiple of 2 or more of (360 ° / number of teeth T of the entire circumferential core). A motor according to any one of claims 1 to 3,
A motor characterized in that there are at least two kinds of angles formed by circumferential positions of connecting portions of the divided cores adjacent to each other in the circumferential direction. A motor according to any one of claims 1 to 4,
A motor having a symmetry axis in which the tooth positions are line-symmetric and a circumferential position of a connecting portion of the divided core is not line-symmetric. A motor according to any one of claims 1 to 5,
Each of the linear divided cores is formed by punching from the plate member in such a manner that the teeth face each other in opposite directions, and the direction of the teeth with respect to the plate member is set on the linear divided core. A motor characterized in that a discriminating section that can be discriminated is provided. The motor according to any one of claims 1 to 6,
The stator core is provided between the inner peripheral wall and the outer peripheral wall in an insulator having a cylindrical inner peripheral wall and an outer peripheral wall, or inside the outer peripheral wall in the insulator having a cylindrical outer peripheral wall. Motor.