JP4332024B2 - Vibration motor - Google Patents

Description

  The present invention relates to a vibration motor having an armature core that is unevenly arranged in an astigmatism with a rotation axis as a center.

  Vibration motors are used in mobile phones, pagers, and the like. For example, as this type of vibration motor, as shown in Japanese Patent Laid-Open No. 9-182366 (Patent Document 1), an armature iron core and a winding wound around the armature iron core are unevenly distributed asymptotically with respect to the center of the rotating shaft. There has been proposed a flat vibration motor that generates a vibration force by doing so.

  FIG. 9 shows this type of vibration motor. The armature core 20 has three salient poles 21, 22 and 23, and the left and right salient poles 21 and 23 are arranged with an open angle of approximately 85 ° with respect to the central salient pole 22. Coils 21a, 22a, and 23a are wound around the salient poles. A rotating shaft 24 is inserted and fixed at the center of the armature core 20, and a flat commutator (not shown) is provided on one surface of the armature core 20 with the rotating shaft 24 as the center. Further, a cylindrical field magnet 25 that is magnetized in six poles is disposed opposite to the outer peripheral surface of the armature core 20.

A pair of brushes (not shown) are brought into sliding contact with the flat commutator to energize the coils 21 a, 22 a, and 23 a, thereby exciting the salient poles 21, 22, and 23 of the armature core 20 and field magnets 25. The armature core 20 is rotated by the magnetic action. At this time, since the three salient poles 21, 22, and 23 of the armature core 20 are unevenly arranged, the mass is unbalanced around the rotation axis. Accompanied by strong vibrations.

  The vibration motor configured as described above is generally driven to rotate according to the same electromagnetic theory as a known motor except that the three salient poles 21, 22, and 23 of the armature core 20 are unevenly arranged. The In order to obtain a small and powerful vibration, it is necessary to increase the mass of the armature core 20 and its unbalance (distance of the center of gravity from the rotation axis). However, since there are few salient poles and they are unevenly distributed, there is a problem that the cogging force contributed by mass imbalance concentrates and does not start. Although this problem can be solved slightly by supplying a large amount of current to the coil and increasing the starting force, the power consumption increases, and this problem cannot be adopted especially in applications that require power saving, such as mobile phones. Remains.

  In order to provide a vibration motor that can save power and increase the starting force, the applicant of the present invention disclosed in Japanese Patent Application Laid-Open No. 2003-9490 (Patent Document 2). The opposing gap between the pole and the field magnet is formed narrower than the opposing gap between the left and right salient poles, and the excitation force due to the central salient pole is greater than the excitation force between the left and right auxiliary salient poles. In addition, a new vibration motor is proposed that is configured to generate a magnetic pole having the same polarity as the opposite magnetic pole to the field magnet at the central salient pole at the time of startup, and to urge the armature core to rotate by the repulsive force. did.

According to the vibration motor shown in Patent Document 2, the exciting force by the central salient pole is configured to be larger than the exciting force of the left and right auxiliary salient poles, and the repulsive force with the field magnet by the central salient pole is increased. In addition, when starting up, the armature core can be strongly started by generating a magnetic pole with the same polarity as the opposite magnetic pole of the field magnet at the central salient pole, and the repulsive force with the central salient pole as a large excitation force It became. However, especially in small devices such as mobile phones, further power saving has been required, and a vibration motor with a small starting current and a small driving current is required.
JP-A-9-182366 JP 2003-9490 A

  The problem to be solved by the present invention is to provide a vibration motor capable of increasing the starting torque, increasing the vibration force, and reducing the starting current and the driving current.

  In order to solve the above-mentioned problem, the invention described in claim 1 has a field magnet having six poles magnetized in the circumferential direction, a rotating shaft, and is unevenly distributed in an astigmatic manner around the rotating shaft. Armature cores each having a coil wound around three salient poles each including a central salient pole and a pair of left and right auxiliary salient poles, and the opposing gap between the central salient pole and the field magnet is defined as the auxiliary salient pole. The excitation force of the central salient pole is configured to be greater than the excitation force of the pair of left and right auxiliary salient poles, and the field magnet is connected to the center salient pole at the time of startup. A vibration motor that generates a magnetic pole having the same polarity as the opposing magnetic pole and rotationally biases the armature core by a repulsive force, wherein the armature core is formed by laminating a plurality of magnetic metal plates, and the auxiliary salient pole is Above of the magnetic metal plate disposed at least on the upper and lower surfaces in the axial direction And summarized in that having different opposing angles with magnet.

  According to a second aspect of the present invention, in the first aspect of the invention, the armature core is opposed to the field magnet by bending in the axial direction a magnetic metal plate disposed at least on the upper and lower surfaces in the axial direction. A gist is formed, and the gist is that the opposing angle of the gutter and the auxiliary salient pole in the pair of left and right auxiliary salient poles is different between the upper surface side and the lower surface side.

  Furthermore, the invention described in claim 3 is the same as that described in claims 1 and 2, wherein the armature core is the same in which the facing angles of the flanges formed on the left and right auxiliary salient poles are different. The gist of the present invention is that two magnetic metal plates are polymerized such that the flanges protrude in the axial direction.

  Furthermore, the invention according to claim 4 is the invention according to claims 1 to 3, wherein the armature core includes the central salient pole and a pair of auxiliary salient poles arranged on the left and right of the central salient pole. The gist is that the opening angles with respect to the magnetic center are different.

  According to the present invention, the magnetic center of the auxiliary salient pole is displaced by changing the facing angle of the magnetic metal plate facing the field magnet in the auxiliary salient pole of the armature core laminated with a plurality of magnetic metal plates. Therefore, since the reaction caused by the auxiliary salient pole is reduced, it is possible to reduce the starting current when starting from the stopped state. Furthermore, it is possible to reduce the drive current by reducing the magnetic reaction even while the vibration motor rotates after startup.

  According to the second aspect of the present invention, a collar is formed on the armature core in which a plurality of magnetic metal plates are laminated so as to be opposed to the field magnet, and a pair of auxiliary salient poles and the field of the collar are formed. Since the facing angle with the magnet is varied in the axial direction, the magnetic center of the auxiliary salient pole can be easily displaced by the large area of the collar facing the field magnet. The current can be easily reduced.

  Furthermore, according to the invention described in claim 3, since the two magnetic metal plates having the same shape and having the flange portion having a different facing angle with the field magnet among the pair of auxiliary salient poles are polymerized, Since the armature core can be manufactured by manufacturing one type of magnetic metal plate having the same shape, the manufacturing cost can be reduced.

  Furthermore, according to the invention described in claim 4, by changing the open angles of the magnetic center of the central salient pole and the magnetic center of the auxiliary salient pole on the left and right sides, the magnetic field of the central salient pole is opposed to the opposite field. By displacing the magnetic center of the magnet magnet, when the magnetic pole of the same polarity as the counter magnetic pole is generated at the central salient pole and activated by the repulsive force, the armature core is rotationally biased from the displaced position. Even if it is a starting current, since it can start smoothly, it becomes possible to make a starting current small.

  The vibration motor includes a field magnet magnetized with six magnetic poles in the circumferential direction, a central salient pole and a pair of left and right auxiliary salient poles that have a rotation axis and are arranged in an asymmetry symmetrically about the rotation axis. And three armature cores each having a coil wound thereon. The opposing gap between the central salient pole and the field magnet is formed to be narrower than the opposing gap between the auxiliary salient pole, and the excitation force by the central salient pole is greater than the excitation force of the pair of left and right auxiliary salient poles. It is composed largely. At startup, the central salient pole is magnetically applied to the field magnet by energizing the coil and generating a magnetic pole having the same polarity as the opposite magnetic pole to the field magnet at the central salient pole. The armature core is urged to rotate by the repulsive force. Further, the armature core of the vibration motor is configured by laminating a plurality of magnetic metal plates, and an opposing angle with the field magnet in the auxiliary salient pole disposed in the armature core is The facing angle of the magnetic metal plate disposed on the upper surface in the axial direction is different from the facing angle of the magnetic metal plate disposed on the lower surface in the axial direction. By varying the facing angle in this way, the magnetic center of the auxiliary salient pole is displaced, the magnetic reaction generated between the field magnet and the auxiliary salient pole is reduced, and the system is started from a stopped state. When starting current is made small.

  FIG. 1 is a plan view showing a vibration motor according to the present invention. A flat, substantially cylindrical field magnet 2 having N poles and S poles alternately magnetized in the circumferential direction is disposed on the inner peripheral surface of the case 1 formed in a substantially dish shape. The field magnet 2 is magnetized by either sinusoidal magnetization or trapezoidal magnetization. The field magnet 2 is a bonded magnet or a sintered magnet mainly composed of rare earth such as ferrite, neodymium, iron, and boron. In order to obtain larger vibration as a vibration motor, it is desirable to use a rare earth magnet.

  Inside the field magnet 2, an armature core 3 fixed to a rotary shaft 7 supported by a bearing (not shown) provided in the case 1 is provided. The armature core 3 has three salient poles including a central salient pole 4 and a pair of left and right auxiliary salient poles 5 and 6, and is unevenly arranged in an astigmatic manner with the rotation shaft 7 as a center. In this embodiment, the armature core 3 is configured by laminating two magnetic metal plates. Further, the three salient poles including the center salient pole 4 and the pair of left and right auxiliary salient poles 5 and 6 are arranged such that a magnetic metal plate disposed on the upper and lower surfaces in the axial direction is placed on the opposite surface facing the field magnet 2. The flanges 4b, 5b and 6b are formed by bending in the direction. The formation of the flanges 4b, 5b and 6b increases the surface facing the field magnet 2 and increases the effective magnetic flux.

  As shown in FIG. 2, the pair of left and right auxiliary salient poles 5 and 6 are arranged with an opening angle of about 85 ° between the center salient pole 4 and the center of ribs 5a and 6a described later. Further, the facing gap G1 between the facing surface of the central salient pole 4 facing the field magnet 2 and the field magnet 2 is narrower than the facing gaps G2 and G3 between the pair of left and right auxiliary salient poles 5 and 6. .

  That is, the armature core 3 has a substantially elliptical locus circle formed by the opposed surface of the central salient pole 4 and the opposed surfaces of the pair of left and right auxiliary salient poles 5 and 6, and the center of the field magnet 2. The center of the locus circle is substantially coincident with the rotation axis 7. Thereby, as shown in FIG. 2, the opposing gap length G1 of the central salient pole 4 is made narrower than the opposing gap lengths G2 and G3 of the auxiliary salient poles 5 and 6. Incidentally, the opposing gap lengths G2 and G3 are set to be twice or more of the opposing gap length G1. Note that it is desirable that the opposing gap lengths G2 and G3 of the pair of left and right auxiliary salient poles 4 and 5 are set to substantially the same size.

  Further, the circumferential width of the rib 4 a in the central salient pole 4 is formed larger than the circumferential width of the ribs 5 a and 6 a of the pair of left and right auxiliary salient poles 5 and 6. Coils 8, 9, and 10 are wound around the rib 4a of the central salient pole 4 and the ribs 5a and 6a of the auxiliary salient poles 5 and 6, respectively. The number of turns of the coil 8 wound around the rib 4 a of the central salient pole 4 is larger than the number of turns of the coils 9 and 10 wound around the ribs 5 a and 6 a of the auxiliary salient poles 5 and 6.

  Thus, the magnetic flux density passing through the central salient pole 4 can be increased by forming the width of the rib 4a of the central salient pole 4 larger than the width of the ribs 5a and 6a of the auxiliary salient poles 5 and 6. . Further, the excitation force can be increased by increasing the number of turns of the coil 8 wound around the rib 4a of the central salient pole 4.

  Further, as shown in FIGS. 1 to 3, the pair of left and right auxiliary salient poles 5 and 6 are configured such that the facing angles of the facing surfaces facing the field magnet 2 are different vertically in the axial direction. That is, the opposing angle θ1 on the upper surface side in the axial direction of the auxiliary salient pole 5 is smaller than the opposing angle θ2 on the lower surface side in the axial direction. Conversely, the opposing angle θ3 on the upper surface side in the axial direction of the auxiliary salient pole 6 is smaller than the opposing angle θ4 on the lower surface side in the axial direction. In this embodiment, as described later, the facing angle θ1 and the facing angle θ3, and the facing angle θ2 and the facing angle θ4 are set to the same angle. At this time, the flange portions 5b and 6b formed on the pair of left and right auxiliary salient poles 5 and 6 are also set to the same facing angles θ1, θ2, θ3, and θ4.

  The above-described magnetic metal plate 16 on the upper surface side of the armature core 3 is formed so that the opposing angles of the pair of auxiliary salient poles 5 and 6 with the field magnet 2 including the flanges 5b and 6b are different on the left and right. Has been. The magnetic metal plate 17 on the lower surface side in the figure is also formed in the same shape. Then, as shown in FIG. 4, the opposing angles θ <b> 1 facing the field magnet 2 are obtained by joining and polymerizing the back surfaces of the magnetic metal plates 16, 17 that do not form the flanges 4 a, 5 b, 6 b. θ2, θ3, and θ4 are configured to be different vertically in the axial direction. That is, when the armature core 3 is manufactured, the above-described armature core 3 is easily manufactured by superimposing the two magnetic metal plates 16 and 17 after manufacturing one kind of magnetic metal plate 16 in advance. Can do.

  The armature core 3 configured as described above is provided with a planar commutator 11 centering on the rotating shaft 7. In the commutator 11, nine segments 13 formed in a substantially trapezoidal shape formed by printed wiring on one surface of the insulating plate 12 are arranged on the circumference. Further, a terminal portion 14 is formed by printed wiring at one end of the insulating plate 12, and the starting end and the terminal end of the above-described three coils 8, 9, 10 are electrically connected to the terminal portion 14. Further, the terminal portion 14 and the nine segments 13 are electrically connected by a printed wiring (not shown).

  A pair of brushes 15 disposed at an open angle of 180 ° is in sliding contact with the segment 13 of the commutator 11. The brush 15 is formed of a conductive metal plate having elasticity, and the tip portion is oriented in the rotational direction as shown in FIG. Further, the tip portion is bifurcated and the bifurcated portion is in sliding contact with the segment 13 by an appropriate pressure. The base end of the brush 15 is fixedly disposed on a lid (not shown). This lid is covered with the case 1 described above. The base end of the brush 15 is connected to a DC power source (not shown) via a connector or a lead wire provided in the case 1.

  Next, the rotation of the vibration motor configured as described above will be described with reference to FIG. FIG. 5A shows a state where the vibration motor is stopped. Since the coils 8, 9, 10 are not energized, the central salient pole 4 and the auxiliary salient poles 5, 6 are not excited. At this time, the center of the central salient pole 4 having the narrowest gap with the field magnet 2 is stabilized by being attracted to the magnetic pole center of the N pole of the field magnet 2, for example, and the armature core 3 is stopped. Yes.

  Thereafter, each coil 8, 9, 10 is energized through the commutator 11, and the N pole is excited on the opposite surface of the central salient pole 4, while the one auxiliary salient pole 5 has the N pole and the other auxiliary salient pole. The pole 6 is excited with the S pole. Since the magnetic pole excited by the central salient pole 4 is the same as the N pole of the field magnet 2, they tend to repel each other. At this time, the N pole excited in one auxiliary salient pole 5 is attracted to the S pole in the vicinity of the field magnet 2, and the S pole excited in the other auxiliary salient pole 6 is further in the vicinity of the field magnet 2. By being attracted to the pole, the armature core 3 is displaced in the counterclockwise direction indicated by the arrow. Thereby, the repulsive force of the center salient pole 4 and the field magnet 2 acts, the armature core 3 starts to rotate counterclockwise as indicated by the arrow, and the vibration motor is started.

  As described above, the width of the rib 4a of the central salient pole 4 is made larger than the width of the ribs 5a, 6a of the auxiliary salient poles 5 and 6, and the magnetic flux density passing through the central salient pole 4 is increased. Since the number of turns of the coil 8 wound around the salient pole 4 is larger than the number of turns of the coils 9 and 10 wound around the auxiliary salient pole 5, the exciting force of the center salient pole 4 is greatly increased. . For this reason, since the armature core 3 is urged counterclockwise by the strong repulsive force between the central salient pole 4 and the field magnet 2, it can be easily started.

  When the armature core 3 is rotated by approximately 40 ° after the start-up, the direction of current flowing through the coils 8, 9, and 10 is switched by the commutator 11, and the armature core 3 is in the position shown in FIG. . That is, the magnetic poles excited by the central salient pole 4 and the one auxiliary salient pole 5 do not change, but the other auxiliary salient pole 6 is excited by the N pole. As a result, the N pole of the central salient pole 4 is further attracted to rotation by being attracted to the S pole of the field magnet 2 in the forward direction of rotation, and the S pole of one auxiliary salient pole 5 is In response to the repulsion by the S pole, the armature core 3 is further rotated counterclockwise.

  When the armature core 3 is rotated to the position shown in FIG. 5C, the central salient pole 4 is excited to the S pole, one auxiliary salient pole 5 is the S pole, and the other auxiliary salient pole 6 is the N pole. Excited and has a magnetic pole arrangement opposite to the magnetic pole relationship shown in FIG. As a result, the magnetic pole excited by the central salient pole 4 is the same as the S pole of the field magnet 2, so that the repulsive force is received, and the S pole excited by the one auxiliary salient pole 5 is the front field magnet 2 in the rotation direction. The N pole excited by the other auxiliary salient pole 6 is further attracted to the N pole of the field magnet 2 forward in the rotation direction, and the armature core 3 is further urged to rotate counterclockwise. The

  After that, when the armature core 3 rotates to the position shown in FIG. 5D, the S pole of the central salient pole 4 is further rotated and biased by being attracted to the N pole of the field magnet 2 that is forward in the rotation direction. The N pole of one of the auxiliary salient poles 5 is repelled by the repulsion by the N pole of the field magnet 2, and the armature core 3 continues to rotate further counterclockwise. Thereafter, the salient poles of the armature core 3 are changed to the field magnets 2 by appropriately switching the energizing directions of the coils 8, 9, 10 for each rotation angle of 40 ° by the nine segments 13 of the commutator 11. The magnetic poles are urged to rotate by repeatedly repelling and attracting. When the energization of the coils 8, 9, 10 is stopped, the magnetic center of the central salient pole 4 and the magnetic pole center of the field magnet 2 are stopped while being attracted to each other.

  Since the above-described vibration motor has a small number of poles of the armature core 3, a rotation speed of several thousand revolutions / minute to 10,000 thousand rotations / minute is obtained, and a large vibration is obtained by this rotation. That is, as the three salient poles unevenly distributed with respect to the field magnet 2, the opposing gap with the central salient pole 4 is formed narrower than the opposing gap with the auxiliary salient poles 5, 6. Is further biased toward the center salient pole 4 side, and as a result, strong vibration is obtained.

  Further, the exciting force by the central salient pole 4 is made larger than the exciting force of the auxiliary salient poles 5 and 6, and the repulsive force with the field magnet 2 by the central salient pole 4 is rotated and biased, so that it is relatively small. Even if it is an electric current value, sufficient starting force and rotational urging | biasing force are obtained, and it becomes possible to suppress power consumption. Further, since the cogging force is increased due to the configuration having the central salient pole 4 as a main component, vibration is also generated electromagnetically, so that stronger vibration can be obtained.

  When the vibration motor described above starts from a stable state in which the central salient pole 4 and the field magnet 2 of the armature core 3 are magnetically attracted, the magnetic motor between the central salient pole 4 and the field magnet 2 is mainly used. Utilizing the repulsive force, the rotational force of the armature core 3 is determined and biased by using the attractive force of the auxiliary salient poles 5 and 6 to the magnetic poles of the field magnet 2 in an auxiliary manner. As described above, when the geometric center of the central salient pole 4 and the magnetic center of the field magnet 2 coincide with each other and start from a stable state, the repulsive force for rotating and energizing becomes weak because both balance. Since the torque becomes insufficient, a large starting current is required.

  Therefore, in order to increase the starting torque and reduce the starting current, in the vibration motor described above, the opposing gap length of the opposing surface of the central salient pole 4 facing the field magnet 2 is set in the circumferential direction of the central salient pole 4. Different on the left and right. That is, as shown in FIG. 6, the surface of the central salient pole 4 facing the field magnet 2 is not concentric from the center of the rotation axis, but is opposed to the opposed gap length G5 on the left end side than the opposed gap length G4 on the right end side in the figure. Is set to be narrower. The difference between the opposing gap lengths G4 and G5 is preferably about 0.1 mm when the dimension is 14 mm from the center of the central salient pole 4. In general, the difference in the opposing gap length with respect to the dimension from the center of the central salient pole is expressed as follows. Set from 1.5% to 0.5%.

  With this configuration, when the armature core 3 is stopped, the central salient pole 4 has a substantially geometric center position with respect to the center position of the magnetic pole of the field magnet 2 (indicated by the center line C0). Stable at (indicated by center line C1). If the difference in the opposing gap length is increased, the short opposing gap length side of the central salient pole 4 is shifted so as to be attracted to the magnetic pole center of the field magnet 2, so that the repulsive force becomes small.

  From this state, when the central salient pole 4 is excited by generating a magnetic pole having the same polarity as the opposing magnetic pole to the field magnet 2, the magnetic flux generated from the central salient pole 4 is generated with a bias toward the narrow opposing gap length G5. A difference G6 from the magnetic center position of the magnet 2 occurs. Due to this difference G6, a large repulsive force is generated between the central salient pole 4 and the field magnet 2, so that the starting torque increases.

  In the vibration motor of the present invention, as described above, the auxiliary salient poles 5 and 6 of the armature core 3 have the opposing angle with the field magnet 2 of the magnetic metal plates 16 and 17 disposed on the upper and lower surfaces in the axial direction. It is different. For this reason, the magnetic centers of the auxiliary salient poles 5 and 6 are displaced in a direction away from the central salient pole 4. Further, as described above, since the difference G6 occurs in the magnetic center position between the central salient pole 4 and the field magnet 2, the armature core 3 is slightly counterclockwise as shown in FIG. Stops at the position displaced to. That is, the magnetic center of the auxiliary salient pole 6 is located at a substantially middle point between the S pole and the N pole of the field magnet 2, and the magnetic influence from the field magnet 2 is reduced. On the other hand, the auxiliary salient pole 5 is substantially in the same position as the position of the conventional vibration motor because the armature core 3 is displaced slightly counterclockwise.

  From this state, the coils 8, 9, and 10 are energized to excite the N pole on the opposing surface of the central salient pole 4, while the N auxiliary salient pole 5 has the N pole and the other auxiliary salient pole 6 has the S. Energize the pole. As a result, the N pole excited by the central salient pole 4 and the N pole of the field magnet 2 repel each other, and the N pole excited by one auxiliary salient pole 5 is the S pole in the vicinity of the field magnet 2. The vibration motor is activated by suction. In this state, since the magnetic center of the other auxiliary salient pole 6 is located at an almost middle point of the field magnet 2, the magnetic field generated between the field magnet 2 and the auxiliary salient pole 6 is almost free. Reaction is reduced. After the armature core 3 starts to rotate counterclockwise as described above, the other auxiliary salient pole 6 excited to the S pole approaches the N pole of the field magnet 2 as shown in FIG. . At this time, since the magnetic center of the auxiliary salient pole 6 is displaced in a direction away from the central salient pole 4, the distance between the magnetic pole of the auxiliary salient pole 6 and the N pole of the field magnet 2 is small. As the attractive force increases, the rotational torque increases and the drive current decreases.

  FIG. 8 shows another embodiment for making the opposing gap between the field magnet and the auxiliary salient pole wider than the opposing gap with the central salient pole. That is, an imaginary trajectory circle having a radius r1 formed by opposing surfaces of the central salient pole 4 and the three salient pole field magnets composed of the pair of left and right auxiliary salient poles 5 and 6 is made substantially circular and the field. It is formed smaller than the radius r2 of the inner surface of the magnet 2, and the center O1 of the locus circle is biased toward the central salient pole 4 side with respect to the center O0 of the rotating shaft 7. At this time, the center of the field magnet 2 is substantially coincident with the center O0 of the rotating shaft 7. Also in this embodiment, the opposing angles of the opposing surfaces of the pair of left and right auxiliary salient poles 5 and 6 that oppose the field magnet 2 are configured to be different vertically in the axial direction.

  As a result, since the central salient pole 4 approaches the field magnet 2, the opposing gap is reduced, and the auxiliary salient poles 5 and 6 are maintained in a wide state, although the opposing gap with the field magnet 2 is slightly reduced. Therefore, it can be made wider than the gap facing the central salient pole 4. The three salient poles that are unevenly arranged in this way are configured so that the mass is unbalanced around the rotation axis, so that strong vibration can be generated as the armature core 3 rotates. Further, since the magnetic center of the auxiliary salient pole 6 is displaced in the direction away from the central salient pole 4, the rotational torque is increased and the drive current is reduced as in the above-described embodiment.

  The vibration motor according to the present invention is activated by a repulsive force between the salient poles of the armature core 3 and the magnetic poles of the field magnet 2 and obtains a rotational biasing force. In order to obtain a large starting torque, it is necessary to provide a difference between the magnetic pole center of the field magnet 2 and the magnetic center of the central salient pole 4 at the time of stopping. In the third embodiment, a difference is made between the centers of the pair of auxiliary salient poles by making the left and right magnetic centers different from each other. That is, the magnetic centers of the auxiliary salient poles 5 and 6 are displaced by forming the opening angles of the pair of auxiliary salient poles 5 and 6 asymmetrically on the left and right. As a means for asymmetrical, a substantial opening angle can be asymmetrically formed by changing the opposing angles of the magnetic metal plates 16 and 17 arranged on the upper and lower surfaces in the axial direction with the field magnet 2.

  In this way, by making the magnetic center of the auxiliary salient pole different on the left and right, the magnetic center of the central salient pole 4 with respect to the center of the magnetic pole of the field magnet 2 is displaced, and as described above, a large repulsive force is obtained. In addition, the starting current can be reduced.

  Needless to say, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the present invention. In the embodiment described above, two magnetic metal plates are superposed, but a plurality of magnetic metal plates of three or more may be superposed. In this case, the flange portion may be formed on the magnetic metal plates on the upper and lower surfaces in the axial direction, and the intermediate magnetic metal plate may be formed flat or may not be formed. Further, when the auxiliary salient poles are different on the left and right, they may be overlaid so as to be divided by half of the plurality of magnetic metal plates. Furthermore, although the vibration motor having the above-described configuration has been described as a flat type, it is not limited to the flat type and may be applied to a cylindrical type. The commutator may not be a flat type but may be a cylindrical commutator.

  The present invention can be applied to a vibration motor having an armature core used for a mobile phone, a pager, or the like.

It is a top view which shows the 1st Example of the vibration motor concerning this invention. It is explanatory drawing which shows the dimensional relationship of the vibration motor in FIG. (A) (B) is a top view which shows the magnetic metal plate which comprises an armature core. It is sectional drawing which shows the salient pole of the vibration motor concerning this invention. (A) thru | or (D) is explanatory drawing which shows rotation operation | movement of the vibration motor concerning this invention. It is a principal part top view which shows the modification of the center salient pole in the vibration motor concerning this invention. It is explanatory drawing which shows the magnetic center of the vibration motor in FIG. It is a top view which shows the 2nd Example of the vibration motor concerning this invention. It is a top view which shows the conventional vibration motor.

Explanation of symbols

2 Field magnet 3 Armature core 4 Central salient poles 5, 6 Auxiliary salient poles 4a, 5b, 6b 鍔 part 7 Rotating shafts 8, 9, 10 Coil 11 Commutators 16, 17 Magnetic metal plates θ1, θ2, θ3, θ4 Opposing angles G1, G2, G3 Opposing gaps G1, G2 Opposing gap length G6 Difference

Claims (4)

Three field magnets having a magnetic pole magnetized with six magnetic poles in the circumferential direction, a central salient pole and a pair of left and right auxiliary salient poles that have a rotational axis and are unevenly distributed in astigmatism around the rotational axis An armature core in which a coil is wound around each salient pole, and the opposing gap between the central salient pole and the field magnet is formed narrower than the opposing gap between the auxiliary salient pole and the center salient pole. The excitation force is configured to be greater than the excitation force of the pair of left and right auxiliary salient poles, and at the time of start-up, a magnetic pole having the same polarity as the opposite magnetic pole to the field magnet is generated at the central salient pole, and the repulsive force causes the armature A vibration motor that urges the iron core to rotate,
The armature core is formed by laminating a plurality of magnetic metal plates,
The auxiliary salient pole is a vibration motor characterized in that the opposing angle of the magnetic metal plate disposed at least on the upper and lower surfaces in the axial direction with the field magnet is different.   The armature iron core is formed with a flange that faces the field magnet by bending a magnetic metal plate disposed at least on the upper and lower surfaces in the axial direction in the axial direction, and the flange in the pair of left and right auxiliary salient poles. The vibration motor according to claim 1, wherein the opposing angle of the auxiliary salient pole is different between the upper surface side and the lower surface side.   The armature core includes two magnetic metal plates so that the flanges protrude in the axial direction from the same magnetic metal plate with the opposite angles of the flanges formed on the left and right auxiliary salient poles. The vibration motor according to claim 1 or 2, wherein the plate is polymerized.   The vibration motor according to any one of claims 1 to 3, wherein the armature core has different open angles between the central salient pole and the magnetic centers of a pair of auxiliary salient poles arranged on the left and right sides of the central salient pole.

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