JP2014241684A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor capable of reducing the volume of sound which is generated when a rotor is accelerated or decelerated.SOLUTION: In a motor 1, a magnet 6 is formed with four couples of S poles and N poles and in a stator core 8, ten salient poles 80 are formed at equal angle intervals. Among the plurality of salient poles 80, one of two salient poles 80 dislocated at 72° in the angle position is a first salient pole 81 around which a first coil 76 is wound and the other is a second salient pole 82 around which a second coil 77 is wound. Regarding the first salient pole 81 and the second salient pole 82, a radial dimension is longer than that of the other salient poles 80. A radial dimension of a portion where the first coil 76 is wound around the first salient pole 81 and a radial dimension of a portion where the second coil 77 is wound around the second salient pole 82 are longer than the radial dimension of the other salient poles 80.

Description

  The present invention relates to a motor in which a coil is wound around two salient poles among a plurality of salient poles of a stator core provided along a circumferential surface of a magnet.

  In a display device such as an automobile meter device or a watch, a structure in which a pointer is attached to an output shaft of a motor may be employed (see Patent Document 1). As a motor used in such a display device, a configuration in which a plurality of salient poles of a stator core are arranged along a peripheral surface of a magnet, and a coil is wound around two salient poles among the plurality of salient poles ( Patent Document 2). In the motor described in Patent Document 2, three or five pairs of S poles and N poles are arranged on the outer peripheral surface of the magnet, and the number of salient poles is eight, and two salient poles whose angular positions are shifted by 90 °. The coil is wound around.

JP 2013-57567 A Japanese Patent No. 4125371

  Regarding the motor used in the display device described in Patent Document 1, in addition to obtaining a sufficient excitation torque, it is required to reduce the volume generated when the rotor is accelerated or decelerated. However, the motor described in Patent Document 2 cannot sufficiently cope with this.

  In view of the above problems, an object of the present invention is to provide a motor capable of reducing the volume generated when a rotor is accelerated or decelerated.

  In order to solve the above-described problems, a motor according to the present invention includes a rotor including a magnet having S poles and N poles alternately provided at equal angular intervals in the circumferential direction, and a gap in the circumferential surface. A stator core having a plurality of salient poles facing each other in the circumferential direction, a first coil wound around the first salient pole among the plurality of salient poles, and the first of the plurality of salient poles. A stator having a second coil wound around a second salient pole spaced circumferentially around the salient pole, and in the magnet, four pairs of the S pole and the N pole are formed, and the stator core Then, ten salient poles are formed at equiangular intervals, and the angular positions of the first salient pole and the second salient pole are shifted by 72 ° in the circumferential direction.

  In the motor according to the present invention, the magnet includes four pairs of S poles and N poles at equal angular intervals, and the stator core has ten salient poles formed at equal angular intervals. For this reason, an excitation torque sufficient for the rotation of the rotor can be obtained. Moreover, when the change of the detent torque with respect to the electrical angle was verified with respect to the motor having such a configuration, the magnet in which three or five pairs of S poles and N poles were formed in the magnet and eight salient poles were formed in the stator core. Therefore, the change in detent torque is small. For this reason, since the vibration of the rotor is small, the volume generated when the rotor is accelerated or decelerated can be reduced, and the noise can be reduced.

  In the present invention, the stator core is preferably formed by laminating a plurality of magnetic plates. According to this configuration, even when there are many salient poles, the magnetic plate is thin when the magnetic plate is punched into the shape of the stator core, so that the magnetic plate can be punched efficiently and accurately.

  In the present invention, among the plurality of salient poles, the first salient pole and the second salient pole are longer in the radial direction than the other salient poles, and the first coil is wound around the first salient pole. It is preferable that the radial dimension of the portion and the radial dimension of the winding portion of the second coil with respect to the second salient pole are longer than the radial dimension of the other salient pole. According to such a configuration, a sufficient number of coil turns can be ensured.

  In the present invention, it is preferable that a gear reduction mechanism for reducing and transmitting the rotation of the rotor is provided. According to such a configuration, there is no need to provide a gear reduction mechanism outside the motor.

  In the motor according to the present invention, the magnet includes four pairs of S poles and N poles at equal angular intervals, and the stator core has ten salient poles formed at equal angular intervals. For this reason, an excitation torque sufficient for the rotation of the rotor can be obtained. Moreover, when the change of the detent torque with respect to the electrical angle was verified with respect to the motor having such a configuration, the magnet in which three or five pairs of S poles and N poles were formed in the magnet and eight salient poles were formed in the stator core. Therefore, the change in detent torque is small. For this reason, since the vibration of the rotor is small, the volume generated when the rotor is accelerated or decelerated can be reduced, and the noise can be reduced.

It is explanatory drawing of the motor to which this invention is applied. It is a graph which shows the result of having calculated | required the characteristic of the motor to which this invention was applied by simulation. It is explanatory drawing of the motor which concerns on the comparative example with respect to this invention. It is a graph which shows the result of having calculated | required the characteristic of the motor which concerns on the comparative example 1 of this invention shown to Fig.3 (a) by simulation. It is a graph which shows the result of having calculated | required the characteristic of the motor which concerns on the comparative example 2 of this invention shown in FIG.3 (b) by simulation.

  A motor to which the present invention is applied will be described below with reference to the drawings.

(Explanation of motor)
FIG. 1 is an explanatory view of a motor to which the present invention is applied. FIGS. 1A, 1B, and 1C are a plan view of a motor, a side view of the motor, and a plan view of a stator and the like.

  As shown in FIGS. 1A and 1B, the motor 1 of this embodiment includes a case 3, a rotor 5 rotatably supported by the case 3, and a stator 7 disposed around the rotor 5. Have. In this embodiment, a support shaft 51 is fixed to the case 3, and the rotor 5 is rotatably supported by the support shaft 51. Therefore, the rotor 5 is rotatably supported by the case 3 via the support shaft 51. Further, the motor 1 has a reduction gear mechanism 9 that reduces the rotation of the rotor 5 and transmits it to the output shaft 90. The reduction gear mechanism 9 is also supported by the case 3 like the rotor 5 and the stator 7. ing.

  The rotor 5 includes a pinion 53 that is rotatably supported by a support shaft 51, and a cylindrical magnet 6 that is integrated with the pinion 53. In this embodiment, the magnet 6 and the pinion 53 are integrated by insert molding. For this reason, the magnet 6 and the pinion 53 are coupled by the resin disc portion 50. In this embodiment, the magnet 6 is a ferrite type.

  The stator 7 includes a stator core 8 provided with a plurality of salient poles 80 facing the outer circumferential surface 60 (peripheral surface) of the magnet 6 with a gap, and an insulator 71 on the first salient pole 81 among the plurality of salient poles 80. And a second coil 77 wound around the second salient pole 82 via the insulator 72 among the plurality of salient poles 80. Two terminals 710 for feeding power to the first coil 76 are held at the end of the insulator 71, and two terminals 720 for feeding power to the second coil 77 are held at the end of the insulator 72. The terminals 710 and 720 are wound around the winding start and winding end of the first coil 76 and the winding start and winding end of the second coil 77.

  The reduction gear mechanism 9 includes a first gear 91 having a large-diameter gear 91a that meshes with the pinion 53, and a large-diameter second gear 92 that meshes with the small-diameter gear 91b of the first gear 91. An output shaft 90 is fixed to the two gears 92.

  In the motor 1 configured as described above, the drive pulse of each phase is supplied to the first coil 76 and the second coil 77 via the terminals 710 and 720, whereby the rotor 5 is rotated and the rotation of the rotor 5 is decelerated. This is transmitted to the output shaft 90 via the gear mechanism 9. When a pointer-type display device is configured using the motor 1, a pointer (not shown) is fixed to the output shaft 90. In such a display device, the angular position of the pointer is switched by the drive pulse supplied to the first coil 76 and the second coil 77 via the terminals 710 and 720. At this time, if a driving pulse for forward rotation is supplied to the terminals 710 and 720 and the pointer is rotated clockwise to the target position, and then a driving pulse for stopping is supplied to the terminals 710 and 720, the pointer is moved to the target position. Can be stopped. In this state, if a driving pulse for reverse rotation is supplied to the terminals 710 and 720, the pointer can be rotated counterclockwise to another target position.

(Configuration of magnet 6 and stator core 8)
As shown in FIG. 1C, in the motor 1 of the present embodiment, the magnet 6 is provided with S poles and N poles on the outer circumferential surface 60 alternately at equal angular intervals in the circumferential direction. In this embodiment, the magnet 6 has four pairs of S poles and N poles. For this reason, in the magnet 6, since the S pole and the N pole are formed at equal angular intervals, a total of 8 poles, the angular positions of the S pole and the N pole adjacent in the circumferential direction are shifted by 45 °. .

  The stator core 8 has an opening 84 where the magnet 6 is disposed, and a plurality of salient poles 80 projecting toward the outer peripheral surface 60 of the magnet 6 are provided in the circumferential direction on the inner peripheral edge of the opening 84. They are formed at equiangular intervals. The radially inner end of the salient pole 80 faces the outer peripheral surface 60 of the magnet 6 via a gap, and the gap dimension between the radially inner end of the salient pole 80 and the outer peripheral surface 60 of the magnet 6 is as follows. The same for all of the plurality of salient poles 80. In this embodiment, the number of salient poles 80 is 10, and the angular positions of the salient poles 80 adjacent in the circumferential direction are shifted by 36 °.

  Of the plurality of salient poles 80, two salient poles 80 whose angular positions are shifted by 72 ° in the circumferential direction are used as the first salient pole 81 and the second salient pole 82 in the stator core 8 configured as described above. That is, among the plurality of salient poles 80, one of the two salient poles 80 whose angular positions are shifted by 72 ° is a first in which a cylindrical insulator 71 around which the first coil 76 is wound is fitted. The other is a salient pole 81, and the other is a second salient pole 82 in which a cylindrical insulator 72 around which a second coil 77 is wound is fitted. Here, the angular position of the first salient pole 81 and the second salient pole 82 is shifted by 72 ° means that the circumferential center of the first salient pole 81 and the circumferential center of the second salient pole 82. Means that the angular position is shifted by 72 °. One salient pole 80 around which no coil is wound exists between the first salient pole 81 and the second salient pole 82.

  In this embodiment, among the plurality of salient poles 80, the first salient pole 81 and the second salient pole 82 have a longer radial dimension than the other salient poles 80. For this reason, the radial dimension of the winding portion of the first coil 76 relative to the first salient pole 81 and the radial dimension of the winding portion of the second coil 77 relative to the second salient pole 82 are the other salient poles 80. Longer than the radial dimension. The first salient pole 81 and the second salient pole 82 have the same radial dimension, and the radial dimension of the winding portion of the first coil 76 relative to the first salient pole 81 and the second salient pole 82 second dimension. The dimension in the radial direction of the winding portion of the coil 77 is equal.

  Among the plurality of salient poles 80, salient poles 80 other than the first salient pole 81 and the second salient pole 82 project in the radial direction, that is, from the connecting portion 85 described later toward the outer peripheral surface 60 of the magnet 6. Since all the salient poles 80 have the same length, the radially outer ends of the salient poles 80 other than the first salient pole 81 and the second salient pole 82 are located at the same distance from the magnet 6. On the other hand, since the first salient pole 81 and the second salient pole 82 have a longer radial dimension than the other salient poles 80, the radially outer end of the first salient pole 81 and the second salient pole The end portion on the radially outer side of 82 is located farther from the magnet 6 on the radially outer side than the end portion on the radially outer side of the other salient pole 80.

  Here, the stator core 8 has a frame-like connecting portion 85 that connects the radially outer ends of all the salient poles 80 including the first salient poles 81 and the second salient poles 82. The width dimension of 85 is the same over the entire circumference. For this reason, the connecting portion 85 is an arc portion 86 concentric with the magnet 6 except for the angular range in which the first salient pole 81 and the second salient pole 82 are formed. On the other hand, the angle range in which the first salient pole 81 is formed in the connecting portion 85 is a rectangular portion 87 projecting radially outward in a rectangular frame shape, and the second salient pole 82 is formed. The angle range is a rectangular portion 88 that protrudes radially outward in a rectangular frame shape. Further, a space between the rectangular portions 87 and 88 is a V-shaped portion 89 that is recessed in a V shape radially inward. From the inner edge of the V-shaped portion 89, the first salient pole 81 and the second salient pole. The salient pole 80 located between the projections 82 projects radially inward.

  In this embodiment, the stator core 8 has a plate shape, and is configured by stacking a plurality of magnetic plates punched into the above shape.

(Evaluation result of motor 1)
FIG. 2 is a graph showing the results of the simulation of the characteristics of the motor 1 to which the present invention is applied. FIGS. 2 (a), 2 (b), and 2 (c) show the electrical angle of the motor 1 and the detent torque. 4 is a graph showing a relationship, a graph showing a relationship between an electrical angle of the motor 1 and an excitation torque, and a graph showing a Lissajous figure showing an electromagnetic force applied to the rotor 5 in the radial direction. In FIG. 2C, one direction orthogonal to the rotation center axis of the rotor 5 is defined as an X-axis direction, and a force applied to the rotor 5 in the X-axis direction is defined as a horizontal axis. In FIG. 2C, the direction perpendicular to the rotation center axis of the rotor 5 and the X-axis direction is the Y-axis direction, and the force applied to the rotor 5 in the Y-axis direction is the vertical axis. Further, in the motor 1 used for the evaluation, the stator core 8 is configured by punching a non-oriented electrical steel sheet having a thickness of 0.5 mm into the above shape and stacking three sheets. The magnet 6 has an inner diameter of 6 mm, an outer diameter of 8 mm, and an axial dimension of 3 mm. The first coil 76 and the second coil 77 are each formed by winding a coil wire having a diameter of 0.055 mm 2200 times, and the resistance value for one phase is 220Ω. The driving voltage is 5V.

  FIG. 3 is an explanatory diagram of a motor 1 according to a comparative example with respect to the present invention, and the characteristics of the motor 1 were also obtained by simulation. In the motor according to the first comparative example shown in FIG. 3A, three pairs of S poles and N poles are formed on the magnet 6, and eight salient poles 80 are formed at equiangular intervals on the stator core 8. Further, the angular position of the first salient pole 81 around which the first coil 76 is wound and the second salient pole 82 around which the second coil 77 is wound are shifted by 90 °.

  In the motor according to the second comparative example shown in FIG. 3B, five pairs of S poles and N poles are formed on the magnet 6, and eight salient poles 80 are formed on the stator core 8. Further, the angular position of the first salient pole 81 around which the first coil 76 is wound and the second salient pole 82 around which the second coil 77 is wound are shifted by 90 °. Here, the salient poles 80 are formed at unequal intervals, but the circumferential center of one of the first salient pole 81 and the second salient pole 82 is the boundary portion between the S pole and the N pole. Since the center in the circumferential direction of the other salient pole faces the center in the circumferential direction of the S pole or the center in the circumferential direction of the N pole, there is no problem in generating the excitation torque.

  FIG. 4 is a graph showing results obtained by simulation of the characteristics of the motor according to the first comparative example of the present invention shown in FIG. 3 (a). FIGS. 4 (a), (b), and (c) It is a graph which shows the relationship between the electrical angle of a motor, and a detent torque, the graph which shows the relationship between the electrical angle of a motor, and a driving torque, and the graph which shows the Lissajous figure which shows the electromagnetic force added to the rotor 5 in a radial direction. FIG. 5 is a graph showing the results of the simulation of the characteristics of the motor according to the second comparative example of the present invention shown in FIG. 3 (b). FIGS. 5 (a), (b), and (c) It is a graph which shows the relationship between the electrical angle of a motor, and a detent torque, the graph which shows the relationship between the electrical angle of a motor, and a driving torque, and the graph which shows the Lissajous figure which shows the electromagnetic force added to the rotor 5 in a radial direction.

  4 (a) and 5 (a) are data corresponding to FIG. 2 (a), and FIG. 4 (b) and FIG. 5 (b) are data corresponding to FIG. 2 (b). FIG. 4C and FIG. 5C are data corresponding to FIG. 2C.

  Here, the motor according to the first comparative example shown in FIG. 3A and the motor according to the second comparative example shown in FIG. 3B are the motor 1 to which the present invention is applied, the size of the magnet 6 and the stator core. The basic configuration such as the size of 8 is the same, and only the number of poles of the magnet 6 and the number of salient poles 80 are different.

  As can be seen by comparing the results shown in FIG. 2A with the results shown in FIG. 4A and FIG. 5A, in the motor 1 to which the present invention is applied, the first comparative example is shown. The amount of change in the detent torque is smaller than that of the motor according to the second comparative example. Therefore, since the external force applied to the rotor 5 is small, it can be said that there is little vibration.

  Next, as can be seen by comparing the results shown in FIG. 2B and the results shown in FIG. 4B, the motor 1 to which the present invention is applied is compared with the motor according to the first comparative example. Although the excitation torque is small, the excitation torque necessary for the rotation of the rotor 5 can still be sufficiently obtained. Further, in the motor 1 to which the present invention is applied, the change in excitation torque is equivalent to that of the motor according to the first comparative example.

  Note that when the result shown in FIG. 2B is compared with the result shown in FIG. 5B, the level of the excitation torque is the same. In addition, the motor 1 to which the present invention is applied has a slightly larger change in excitation torque than the motor according to the first comparative example, but the difference is small and can be said to be equivalent.

  As can be seen from a comparison between the results shown in FIG. 2C and the results shown in FIG. 4C, the motor 1 to which the present invention is applied has a radial direction as compared with the motor according to the first comparative example. Thus, the force applied to the rotor 5 is small. For this reason, in the motor 1 to which the present invention is applied, it can be said that the external force applied to the rotor 5 in the radial direction is small as compared with the motor according to the first comparative example, so that the vibration is small.

  When the result shown in FIG. 2C is compared with the result shown in FIG. 5C, the motor 1 to which the present invention is applied has a rotor in the radial direction as compared with the motor according to the first comparative example. Although the force applied to 5 is slightly large, the difference is small and can be said to be equivalent.

(Main effects of this form)
As described above, in the motor 1 of this embodiment, the magnet 6 has four pairs of S poles and N poles formed at equal angular intervals, and the stator core 8 has ten salient poles 80 formed at equal angular intervals. . For this reason, the excitation torque required for the rotation of the motor 1 can be obtained. Further, when the change in the detent torque with respect to the electrical angle in the motor 1 having such a configuration was verified, as described with reference to FIGS. 2 (a), 4 (a), and 5 (a), the magnet 6 A change in detent torque is smaller in the stator core 8 than in the motors according to Comparative Examples 1 and 2 in which three or five pairs of S poles and N poles are formed, and eight salient poles 80 are formed. For this reason, in the motor 1 of this embodiment, since the vibration of the rotor 5 is small, the volume generated when the rotor 5 is accelerated or decelerated can be reduced, and the noise can be reduced.

  The stator core 8 is formed by laminating a plurality of magnetic plates. For this reason, even when there are many salient poles 80 as in this embodiment, the magnetic plate is thin when the magnetic plate is punched into the shape of the stator core 8, so that the magnetic plate can be punched accurately.

  Further, among the plurality of salient poles 80, the first salient pole 81 and the second salient pole 82 have a longer radial dimension than the other salient poles 80, and the winding portion of the first coil 76 with respect to the first salient pole 81. And the radial dimension of the winding portion of the second coil 77 with respect to the second salient pole 82 are larger than the radial dimensions of the other salient poles 80. Therefore, the excitation torque necessary for the rotation of the motor 1 can be obtained with certainty.

  Further, since the motor 1 is provided with the gear reduction mechanism 9 that reduces and transmits the rotation of the rotor 5, it is not necessary to provide the gear reduction mechanism 9 outside the motor 1. Therefore, only by attaching a pointer to the output shaft 90 in the motor 1 of the present embodiment, the main part of the display device can be configured, and the display device can be reduced in size.

(Other embodiments)
In the above embodiment, the rotor 5 is positioned inside the stator 7. However, the present invention may be applied to a motor in which the rotor 5 is positioned outside the stator 7. In this case, the salient pole 80 is configured to protrude radially outward from the stator core 8 and face the inner peripheral surface (peripheral surface) of the magnet 6.

DESCRIPTION OF SYMBOLS 1 Motor 5 Rotor 6 Magnet 7 Stator 8 Stator core 9 Reduction gear mechanism 60 Outer peripheral surface (peripheral surface) of magnet
71, 72 Insulator 76 First coil 77 Second coil 80 Salient pole 81 First salient pole 82 Second salient pole 90 Output shaft

Claims (4)

A rotor provided with magnets having S and N poles alternately arranged at equal angular intervals in the circumferential direction on the circumferential surface;
A stator core in which a plurality of salient poles facing the circumferential surface with a gap are arranged in the circumferential direction, a first coil wound around a first salient pole among the plurality of salient poles, and the plurality of salient poles A stator including a second coil wound around a second salient pole spaced circumferentially around the first salient pole;
Have
In the magnet, four pairs of the S pole and the N pole are formed,
In the stator core, ten salient poles are formed at equiangular intervals,
The motor characterized in that the first salient pole and the second salient pole are misaligned by 72 degrees in the circumferential direction.   The motor according to claim 1, wherein the stator core is formed by stacking a plurality of magnetic plates. Among the plurality of salient poles, the first salient pole and the second salient pole have a longer radial dimension than the other salient poles,
The radial dimension of the winding portion of the first coil with respect to the first salient pole, and the radial dimension of the winding portion of the second coil with respect to the second salient pole are the radial directions of the other salient poles. The motor according to claim 1, wherein the motor is longer than the dimension of the motor.   The motor according to any one of claims 1 to 3, further comprising a gear reduction mechanism that reduces and transmits the rotation of the rotor.

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