JP4035501B2 - Stepping motor - Google Patents

Description

  The present invention relates to a stepping motor, and more particularly to a thin stepping motor that can obtain high torque.

FIG. 11 is a longitudinal sectional view showing a configuration example of a conventional step motor, and FIG. 12 is a partial sectional view schematically showing a state of magnetic flux of a stator of the step motor of FIG. In FIG. 11, two bobbins 101 around which a stator coil 105 is wound concentrically are arranged in the axial direction. These bobbins 101 are sandwiched and fixed from the axial direction by two stator yokes 106, and each stator yoke 106 is fixed. The stator teeth 106a and 106b that are alternately arranged along the circumferential direction of the inner diameter surface of the bobbin 101 are formed on the inner diameter surface. A stator yoke 106 integral with the stator teeth 106a or 106b is fixed to each of the two sets of cases 103. Thus, two stators 102 corresponding to the two stator coils 105 for excitation are configured. A flange 115 and a bearing 108 are fixed to one of the two sets of cases 103, and another bearing 108 is fixed to the other case 103. The rotor 109 is composed of a rotor magnet (rotor magnet) 111 fixed to the rotor shaft 110, and the rotor magnet 111 forms a radial gap with the stator yoke 106 of each stator 102. The rotor shaft 110 is rotatably supported between the two bearings 108. This conventional small step motor has the disadvantage that the outer dimensions of the motor increase because the case 103, the bobbin 101, the stator coil 105, and the stator yoke 106 are concentrically disposed on the outer periphery of the rotor 109. It was. Moreover, for passing the magnetic flux and the end face 106b ₁ of the end face 106a ₁ and the stator teeth 106b primarily stator tooth 106a as shown in FIG. 12 generated by energization of the stator coil 105, effectively act on the rotor magnet 111 In addition, there is a drawback that the motor output does not increase.

  As a solution to the above-described drawbacks, there is a motor configured as described in Patent Document 1. In this proposed motor, a rotor (rotor magnet) composed of permanent magnets equally divided in the circumferential direction and alternately magnetized to different poles is formed in a cylindrical shape, and the axial direction of the rotor (axial direction of the motor) The first coil, the rotor, and the second coil are arranged in order, and the first stator and the first inner magnetic pole portion excited by the first coil are arranged on one outer peripheral surface and inner peripheral surface in the axial direction of the rotor. The second outer magnetic pole portion and the second inner magnetic pole portion that are opposed to each other and are excited by the second coil are configured to face the other outer peripheral surface and inner peripheral surface in the axial direction of the rotor, and the rotor shaft The rotating shaft is taken out from the cylindrical magnet. By setting it as the motor of such a structure, an output is high and the external dimension of a motor can be made small. Furthermore, by reducing the thickness of the magnet, the distance between the first stator and the first inner magnetic pole part and the distance between the second outer magnetic pole part and the second inner magnetic pole part can be reduced. The magnetic resistance of the magnetic circuit can be reduced. Therefore, a large amount of magnetic flux can be generated even if the current flowing through the first coil and the second coil is reduced.

  FIG. 13 is a longitudinal sectional view of the motor having the above-described configuration, in which 201 is a magnet, 202 is a first coil, 203 is a second coil, 204 is a first stator, and 204a and 204b are first coils. , 204c and 204d are first inner magnetic pole portions, 205 is a second stator, 205a and 205b are second outer magnetic pole portions, and 205c and 205d are second inner magnetic pole portions. Reference numeral 206 denotes an output shaft, which is fixed to the magnet 201 and rotates integrally therewith. The output shaft 206 is rotatably supported by bearings 204e and 205e of the first stator 204 and the second stator 205. The connection ring 207 holds the first stator 204 and the second stator 205.

  However, the motor of the type described in Patent Document 1 has a problem that the length in the axial direction becomes long. As a motor that has solved this problem, that is, a motor having a reduced length in the axial direction, there is a motor as shown in FIG. 14 proposed in Patent Document 2, Patent Document 3, and the like. This motor is composed of a plurality of coils 301, 302, and 303 and a disk-shaped magnet 304. The coils 301 to 303 have a thin coin shape as shown in the figure, and the axis thereof is the axis of the magnet 304. They are arranged in parallel. The magnet 304 is magnetized in the axial direction of the disk, and the magnetized surface of the magnet 304 and the axes of the coils 301 to 303 are arranged to face each other.

  Further, as in Patent Document 2 and Patent Document 3, there is a motor as shown in FIG. 16 proposed in Patent Document 4 as a short motor in the axial direction. In the proposed motor, a surface perpendicular to the axial direction of the magnet 305 is divided and magnetized in the circumferential direction, and two coils 306 and 307 are arranged on both sides around the magnet 305. The magnet 305 and the coils 306 and 307 are connected to each other. The two stators 308 and 309 are sandwiched from above and below in the axial direction. As a result, a thin stepping motor can be obtained, which can be incorporated into an exposure amount adjusting device of a camera.

Patent Document 5 discloses a stepping motor that realizes a high torque with a small diameter by stacking a plurality of stator assemblies and connecting a plurality of magnets to one shaft.
Japanese Patent Laid-Open No. 09-331666 Japanese Patent Laid-Open No. 7-213041 JP 2000-50601 A Japanese Patent Laid-Open No. 02-058035 JP 2001-231240 A

  However, in the motors of Patent Document 2 and Patent Document 3, the magnetic flux generated from the coils 301 to 303 does not act on the magnet 304 completely and effectively as shown by the arrows in FIG. Since the center of the rotational force is at a position separated by L from the outer diameter of the motor, the torque generated is small for the size of the motor.

  Moreover, in the said patent document 4, it had the following subjects. First, since the pole teeth of the stators 308 and 309 facing the magnet 305 per phase are about half of the entire circumference, the effective magnetic flux of the magnet 305 can be used only about half or less, which is efficient. Absent. Second, since the portions where the coils 306 and 307 and the stators 308 and 309 are close to each other are only at the upper and lower ends, there are many leakage magnetic fluxes to the outer periphery of the coil, which is not efficient. Third, as described above, since the pole teeth of the stators 308 and 309 facing the magnet 305 are about half of the entire circumference, the range in which the driving force is generated for each excitation phase is also half of the entire circumference. When the driving force is converted into a rotational force, an unnecessary lateral force is likely to be generated, and there is a concern about vibration, noise, rotation unevenness, and deterioration in position accuracy as a stepping motor.

  Further, in Patent Document 5, it is considered that a plurality of general stepping motors shown in FIG. 11 are stacked in the axial direction, but the base unit aims to reduce the height in the axial direction. However, it is magnetized on the outer peripheral surface of the magnet, and in order to obtain a high torque, it is necessary to make it long in the axial direction. As a result, it is difficult to reduce the thickness. Also, in terms of the flow of magnetic flux, it passes between the surface of the outer peripheral surface of the magnet and the stator on the opposite surface, and it cannot be said that the magnetic flux of the magnet is fully utilized, and high torque is Hard to get. Therefore, there is a problem that it is difficult to increase the efficiency even if the units are stacked.

In order to solve the above-mentioned problem, the invention according to claim 1 is a first magnet in which a disk-shaped surface perpendicular to its central axis is divided in the circumferential direction and alternately magnetized to different poles. And the second magnet, the first stator facing the magnetized surface of the first magnet, the opposite side of the first stator across the first magnet, and the first A second stator in a plane parallel to the stator, and substantially concentric with the first magnet and sandwiched between the first stator and the second stator, the first stator and the second stator A first coil that excites the second magnet, a third stator that opposes the magnetized surface of the second magnet, a side opposite to the third stator across the second magnet, and the first 4 in a plane parallel to the stator of 3 A second coil that is substantially concentric with the second magnet and sandwiched between the third stator and the fourth stator, and that excites the third stator and the fourth stator, A stepping motor having an output shaft that fixes the first magnet and the second magnet at a predetermined interval and holds the first magnet and the second magnet so as to rotate together, wherein the first to fourth stators are the first and fourth stators. The first and second magnets have a number of magnetic pole teeth that is ½ of the number of magnetic poles P of the first and second magnets, and the magnetic pole teeth are arranged facing each other across the first magnet. When the combination of the stator is a first stator set, and the combination of the third and fourth stators in which the magnetic pole teeth are arranged facing each other across the second magnet is the second stator set, 1 stator set and the second stator set are combined with a shift of 360 ° / P in the circumferential direction with reference to the phase where the magnetic pole teeth are provided, and the first magnet and the second magnet Are stepping motors which are fixed to the output shaft by shifting their magnetization phases in the circumferential direction by an angle of 360 ° / 2P.

  According to the above configuration, the two-phase stepping motor can be configured as a stepping motor that changes the direction of energization to the two excitation phases sequentially and moves to a position corresponding to the energization phase. In addition, since the distance between the magnetic pole teeth of the second stator and the fourth stator in the portion where the two stator sets are joined is the longest in the circumferential direction, it depends on the difference in the poles excited between the two phases. Mutual magnetic interference is minimized. Therefore, in this configuration of the excitation phase, the maximum magnetic flux is generated and the minimum magnetic resistance is obtained, and the obtained output is increased. Further, since the first coil and the first magnet are sandwiched between the first stator and the second stator, the first coil and the first magnet can be made thin. Further, since the second coil and the second magnet are sandwiched between the third stator and the fourth stator, they can be formed thin.

According to a second aspect of the present invention, there is provided a first magnet and a second magnet which are disc-shaped and whose surfaces perpendicular to the central axis are divided in the circumferential direction and are alternately magnetized to different poles. A first stator facing the magnetized surface of the first magnet, and a surface opposite to the first stator across the first magnet and parallel to the first stator. A second stator, a first stator that is substantially concentric with the first magnet and sandwiched between the first stator and the second stator to excite the first stator and the second stator; A coil, a third stator facing the magnetized surface of the second magnet, and a side opposite to the third stator across the second magnet and parallel to the third stator A fourth stator on the surface and the second stator A second coil disposed substantially concentrically with the magnet and sandwiched between the third stator and the fourth stator to excite the third stator and the fourth stator; the first magnet; A stepping motor having an output shaft that fixes the two magnets at a predetermined interval and rotatably holds them as a unit, and the first to fourth stators of the first and second magnets A combination of the first and second stators, each having a number of magnetic pole teeth that is ½ of the number of magnetic poles P and each magnetic pole tooth facing each other across the first magnet, is a first combination. If the combination of the third and fourth stators, in which the respective magnetic pole teeth are arranged facing each other across the second magnet, is the second stator set, the first stay The set and the second stator set are shifted by an angle of 360 ° / 2P with reference to the phase at which the magnetic pole teeth are provided, and the phase of the first magnet and the second magnet are the same. The stepping motor is fixed to each of the output shafts.

According to a third aspect of the present invention, there is provided a first magnet and a second magnet having a disk shape and a surface perpendicular to the central axis divided in the circumferential direction and alternately magnetized to different poles; A first stator facing the magnetized surface of the first magnet, and a surface opposite to the first stator across the first magnet and parallel to the first stator. A second stator, a first stator that is substantially concentric with the first magnet and sandwiched between the first stator and the second stator to excite the first stator and the second stator; A coil, a third stator facing the magnetized surface of the second magnet, and a side opposite to the third stator across the second magnet and parallel to the third stator A fourth stator on the surface and the second stator A second coil disposed substantially concentrically with the magnet and sandwiched between the third stator and the fourth stator to excite the third stator and the fourth stator; the first magnet; A stepping motor having an output shaft that fixes the two magnets at a predetermined interval and rotatably holds them as a unit, and the first to fourth stators of the first and second magnets A combination of the first and second stators, each having a number of magnetic pole teeth that is ½ of the number of magnetic poles P and each magnetic pole tooth facing each other across the first magnet, is a first combination. If the combination of the third and fourth stators, in which the respective magnetic pole teeth are arranged facing each other across the second magnet, is the second stator set, the first stay The set and the second stator set are combined in the same phase in which the magnetic pole teeth are provided, and the first magnet and the second magnet are arranged in the circumferential direction by an angle of 360 ° / 2P. And a stepping motor that is fixed to the output shaft.

According to the structure of the said Claim 2 and 3 , it can comprise as a stepping motor which changes to the position according to an energization phase by changing the direction of electricity supply sequentially with respect to two excitation phases as a two-phase stepping motor. In this case, since the two stator sets have the same phase, the same stator can be used. In addition, the two stator sets can be assembled with high accuracy, resulting in a high-precision stepping motor.

  According to the present invention, it is possible to provide a stepping motor that is thin and capable of generating high torque, and that has little vibration, noise, and rotation unevenness and high assembly accuracy.

  This is as shown in Examples 1 to 4 below.

  1 to 6 are views showing a stepping motor according to a first embodiment of the present invention, in which FIG. 1 is an exploded perspective view of the stepping motor, FIG. 2 is an axial sectional view of the stepping motor, and FIG. It is a schematic diagram of the side view which shows the phase relationship of a magnet and a stator.

  1 to 3, reference numeral 1 denotes a disk-shaped magnet, and a press-fit portion 1A made of a non-magnetic material fixed to the center of the output shaft 3 by press-fitting or the like and a surface perpendicular to the output shaft 3 are circumferentially arranged. It consists of magnetized portions that are P-divided in the direction (P is an even number and P = 16 in this embodiment) and are alternately magnetized to the N and S poles. The magnetized portions are labeled 1a, 1b, 1c, 1d,. The inner peripheral surface of the press-fit portion 1A is a hole that fits into the output shaft 3, and the outer peripheral surface thereof has a surface that fits into the inner periphery of the magnetized portion, and a semicircular not-shown projection for determining the magnetization phase. In addition, when the output shaft 3 and the second magnet 8 are joined, the magnetizing phase of the magnet is set to a predetermined value between the two magnets so that the magnetizing phase of the two magnets is set to a predetermined angle. It has a circular protrusion 1B protruding in the axial direction that can be an angle. Here, the surface facing the outside of the stepping motor and facing the first stator 5 is magnetized, the magnetized portions 1a, 1c, etc. are magnetized in the S pole, and 1b, 1d, etc. are magnetized in the N pole. The other parts are also magnetized. In addition, a pole opposite to the front side inevitably appears on the back side of the magnetized surface. The magnetized portion of the first magnet is a plastic magnet formed by injection molding, but may be manufactured by a method of joining magnets created by compression molding or the like. Reference numeral 8 denotes a second magnet, which is made up of the same components as the first magnet 1, and will not be described in detail.

  Reference numeral 2 denotes a bearing, which is fixed to the first stator 5 in order to smoothly rotate and slide the output shaft 3, and is made of an oil-impregnated sintered metal such as a nonmagnetic material. Further, it has a thrust receiving surface and faces the press-fit portion of the first magnet 1 with a slight gap to determine the positions of the output shaft 3, the first magnet 1, and the second magnet 8 in the axial direction. Reference numeral 9 denotes a bearing, which is composed of the same parts as the bearing 2, and therefore details thereof are omitted.

  Reference numeral 3 denotes an output shaft, which is a non-magnetic material such as a first magnet 1 and a second magnet 8 that are fixed by press-fitting or bonding, is rotatably supported by the bearing 2 and the bearing 9, and outputs the rotational force. A shaft made of stainless steel. When the first magnet 1 and the second magnet 8 are joined, the first magnet 1 and the second magnet 8 are fixed while being shifted by an angle obtained by dividing 360 ° by twice the number of magnetic poles.

  Reference numeral 4 denotes a first coil, which is disposed at a substantially concentric position outside the first magnet 1 and is fixed to the second stator 6. In the first embodiment, the air-core coil is manufactured and the surface is insulated. A conductive wire may be wound around a bobbin made of an insulating material. Reference numeral 10 denotes a second coil, which is made up of the same components as the first coil 4, and the details thereof are omitted.

  Reference numeral 5 denotes a first stator, a disc made of a soft magnetic material, a comb-shaped magnetic pole teeth 5a and 5b constituting magnetic poles extending in a plane perpendicular to the rotation axis, a hole for supporting the bearing 2, and a later-described A protrusion for matching the phase of the second stator 6 and the magnetic pole teeth is manufactured by a punching press process or the like. In addition, there is a connecting portion that connects the tips of the magnetic pole teeth on the inner diameter side, and this is for the purpose of preventing deformation of the tip portion of each magnetic pole tooth. The number of magnetic pole teeth of the first stator 5 is ½ of the number of magnetic poles of the first magnet 1 and the second magnet 8 as is apparent from FIG. Reference numeral 11 denotes a third stator, which is made up of the same components as the first stator 5 and will not be described in detail.

Reference numeral 6 denotes a second stator, which is a disk made of a soft magnetic material, comb-shaped magnetic pole teeth 6a and 6b constituting magnetic poles extending in a plane perpendicular to the rotation axis, a hole penetrating the output shaft 3, and a first stator. A notch for aligning the phase of the magnetic pole teeth with the protrusion of the stator 5 is manufactured by a punching press, drawing or forging process, etc., and has a standing wall shape portion on the outer periphery. The phase of the magnetic pole teeth is adjusted and fixed in a process or the like. By this standing wall shape portion, the first stator 5 and the second stator 6 are connected with less magnetic resistance. In addition, there is a connecting portion that connects the tips of the magnetic pole teeth on the inner diameter side, and this is for the purpose of preventing deformation of the tip portion of each magnetic pole tooth. Further, on the back surface, there is a protrusion that determines the position in the rotational direction so that the phase of the second stator 6, the ground plane 7, and the magnetic pole teeth is a predetermined phase. The number of magnetic pole teeth of the second stator 6 is also ½ of the number of magnetic poles of the first magnet 1 and the second magnet 8 as is apparent from FIG. Reference numeral 12 denotes a fourth stator, which is made up of the same components as the second stator 6 and will not be described in detail.

  Reference numeral 7 denotes a ground plate, which has a non-magnetic material or a structure in which the magnetic resistance is increased, and has a positioning hole for connecting the second stator 6 and the fourth stator 12 so as to have a predetermined phase. Then, the displacement angle of the positioning hole is 360 ° / P, which is a position rotated by 22.5 °. Further, the magnetic pole teeth of the second stator 6 and the fourth stator 12 are fixed in close contact with or adhered to each other, thereby preventing deformation of the magnetic pole teeth.

  In the cross-sectional view of FIG. 2, as shown in the upper half of the stepping motor, the first stator 5 and the second stator 6 sandwich the first coil 4 and the first magnet 1 from above and below, The cross sections are combined in a substantially U-shape, and the distance between the surfaces perpendicular to the output shaft 3 that is the respective rotation shafts of the first stator 5 and the second stator 6 is fixed at a predetermined interval. . Further, as will be described later, the phase of the magnetic pole teeth of each stator is at a position where the magnetic pole teeth face each other across the first magnet 1. At the same time, since the axial position of the first magnet 1 is also determined by the bearing 2 fixed to the first stator 5, the gap between the first magnet 1 and the first stator 5, and the first magnet 1. The second stator 6 also has a predetermined gap. Therefore, when the first coil 4 is energized, the first stator 5 and the second stator 6 around it are excited, and an N pole or an S pole is generated at the magnetic pole tooth portion. The poles generated in each stator are opposite to each other. Thus, the upper unit of the stepping motor is formed.

  The lower unit of the stepping motor is also composed of the same parts as the upper unit, and both are joined with the base plate 7 as a boundary with the axial direction reversed from that of the upper unit. That is, the second magnet 8 is fixed to the output shaft 3, and the bearing 9 restricts the position in the upper and lower directions in FIG. The third stator 11 and the fourth stator 12 sandwich the second coil 10 up and down. As shown in FIG. 3, in the upper unit, the magnetic pole teeth 5 a of the first stator 5 are provided with magnetic pole teeth 6 a of the second stator 6, and the magnetic pole teeth 5 b of the first stator 5 are provided with magnetic poles of the second stator 6. The teeth 6b face each other with the first magnet 1 in between. Similarly, in the lower unit, the magnetic pole teeth 11a of the third stator 11 have magnetic pole teeth 12a of the fourth stator 12, and the magnetic pole teeth 11b of the third stator 11 have magnetic pole teeth 12b of the fourth stator 12. The second magnet 8 is opposed to the other. Further, the upper unit and the lower unit are assembled such that the magnetic pole teeth of the second stator 6 and the magnetic pole teeth of the fourth stator 12 are shifted by 360 ° / P, that is, 22.5 °.

  As shown in FIG. 3, when the upper unit and the lower unit are joined, the magnetic pole teeth of the second stator 6 and the magnetic pole teeth of the fourth stator 12 are shifted in the rotational direction by an angle of PHs. Further, the phases of the magnetization angles of the first magnet 1 and the second magnet 8 are shifted by PHm. Here, O is the angle pitch between the magnetic pole teeth of the stator and M is the angle of the magnetized width of the magnet. L is 360 × 2 / P, which is 45 degrees here. M is 360 / P, which is 22.5 degrees here. Accordingly, PHs is 22.5 degrees at O / 2 and PHm is 11.25 degrees at M / 2.

  As shown in FIG. 3, the magnetic pole teeth 12 a of the fourth stator 12 are present in the middle of the magnetic pole teeth 6 a and 6 b of the second stator 6 in the circumferential direction. Therefore, if the distance between the two excitation phases is the same, the distance between the magnetic pole teeth 12a of the fourth stator 12 and the magnetic pole teeth 6a and 6b of the second stator 6 is the longest. It can be seen that it has the least influence on the magnetic interference between the magnetic pole teeth generated by. Thereby, in the configuration of the excitation phase, the maximum magnetic flux is generated and the minimum magnetic resistance is obtained, and the obtained output is increased.

  Here, the magnetic circuit in the upper unit will be described with reference to the cross-sectional view of FIG.

  When the first coil 4 on the outer periphery is energized, a magnetic flux is generated around the first coil 4, and the magnetic flux is guided to the second stator 6 around the first coil 4 and goes toward the center of the output shaft 3. Here, since the comb-shaped magnetic pole teeth 6a, 6b and the like are opposed to the thin first magnet 1, the magnetic flux is directed toward the comb-shaped magnetic pole teeth 5a, 5b of the first stator 5 on the opposite side. Pass through the first magnet. Since the first magnet 1 is thin, the distance between the first stator 5 and the second stator 6 is small, and the first magnet 1 and the second stator 6, and the first magnet 1 and the first stator 5 Is the minimum distance between the rotating body and the stationary body, and since this is short, the magnetic loss in this portion is small. The magnetic flux that has passed through the first magnet 1 is guided to the first stator 5 and reaches the periphery of the first coil 4. Since each stator is a soft magnetic material such as SUY (electromagnetic soft iron) with low magnetic resistance, the magnetic loss in this portion is also small. Therefore, since a large amount of magnetic flux can be generated even if the current flowing through the first coil 4 is reduced, the output is high while maintaining a thin shape.

  The first stator 5, the second stator 6, the third stator 11, and the fourth stator 12 have a connecting portion that connects the tips of the magnetic pole teeth on the inner diameter side. This portion is for the purpose of preventing the deformation of the portion, and this portion is opposed to the press-fit portions 1A, 8A made of a nonmagnetic material on the inner peripheral portion of the first magnet 1 and the second magnet 8, so No leakage flux is generated with respect to the flow. Further, since the bearing 2 and the bearing 9 are also made of a nonmagnetic material, no leakage magnetic flux is generated. Further, since the output shaft 3 is also made of nonmagnetic stainless steel, no leakage magnetic flux is generated.

  Since the lower unit also has a symmetrical structure, it has exactly the same function, and detailed description thereof is omitted.

  Next, the rotational drive of the stepping motor in the above configuration will be described with reference to FIGS.

  FIG. 3 is a schematic side view showing the phase relationship between the magnet and the stator as described above, and FIG. 4 shows a state in which the magnet is rotated 11.25 degrees by switching energization to the coil from the state of FIG. FIG. 5 is a schematic diagram of a side view, FIG. 5 is a schematic diagram of a side view showing a state in which the magnet is further rotated 11.25 degrees by switching energization to the coil from the state of FIG. 4, and FIG. It is a schematic diagram of the side view which shows the state which switched the electricity supply of 1 and rotated the magnet further 11.25 degree | times.

  In the state of FIG. 3, the first coil 4 (not shown) is positively energized so that the magnetic pole teeth 5 a and 5 b of the first stator 5 become N poles, and the magnetic pole teeth 6 a and 6 b of the second stator 6. Is made the S pole, and simultaneously, positive current is supplied to the second coil 10 (not shown), so that the magnetic pole teeth 11a and 11b of the third stator 11 become the S pole and the magnetic pole teeth 12a and 12b of the fourth stator 12 Shows the case where N is the N pole. At this time, a rotational force is generated in which the centers of the magnetized portions 1a and 1c in which the upper surface side of the first magnet 1 is magnetized to the S pole are directed toward the centers of the magnetic pole teeth 5a and 5b of the first stator 5 (see FIG. 3) and the center of the magnetized portions 8 a and 8 c magnetized on the S pole on the lower surface side of the second magnet 8 toward the center of the magnetic pole teeth 11 a and 11 b of the third stator 11. A force is generated (in the direction opposite to the arrow R in FIG. 3), so that the state of FIG.

Next, while maintaining positive energization to the first coil 4 from the state of FIG. 3, that is, the magnetic pole teeth 5 a and 5 b of the first stator 5 are set to N poles, and the magnetic pole teeth 6 a and 6 b of the second stator 6. The second coil 10 is switched to reverse energization with the S-pole. Then, the magnetic pole teeth 11a and 11b of the third stator 11 are excited to the N pole, the magnetic pole teeth 12a and 12b of the fourth stator 12 are excited to the S pole, and the second magnet 8 is set to the S pole on the lower surface. The magnetized portions 8b and 8d magnetized generate a rotational force toward the centers of the magnetic pole teeth 11a and 11b of the third stator 11, and start to rotate in the direction of arrow R in the figure. And in the state shown in FIG. This state is a state in which the first magnet 1 and the second magnet 8, that is, the output shaft 3 are rotated 11.25 degrees in the arrow R direction from the state of FIG.

  Next, while maintaining the reverse energization to the second coil 10 from the state of FIG. 4, that is, the magnetic pole teeth 11 a and 11 b of the third stator 11 are set to the N pole, and the magnetic pole teeth 12 a and 12 b of the fourth stator 12. The first coil 4 is switched to reverse energization with the S-pole. Then, the magnetic pole teeth 5a and 5b of the first stator 5 are excited to the S pole, the magnetic pole teeth 6a and 6b of the second stator 6 are excited to the N pole, and the first magnet 1 is turned to the N pole on the upper surface. The magnetized magnetized portions 1b and 1d generate a rotational force toward the centers of the magnetic pole teeth 5a and 5b of the first stator 5, and start to rotate in the direction of arrow R in the figure. Then, the balance is kept stationary in the state shown in FIG. This state is a state in which the first magnet 1 and the second magnet 8, that is, the output shaft 3 are rotated 11.25 degrees in the arrow R direction from the state of FIG.

  Next, while maintaining reverse energization to the first coil 4 from the state of FIG. 5, that is, the magnetic pole teeth 5 a, 5 b of the first stator 5 are made S poles, and the magnetic pole teeth 6 a, 6 b of the second stator 6. Is switched to the positive polarity while the second coil 10 is energized. Then, the magnetic pole teeth 11a and 11b of the third stator 11 are excited to the S pole, the magnetic pole teeth 12a and 12b of the fourth stator 12 are excited to the S pole, and the second magnet 8 is set to the N pole on the lower surface. The magnetized portions 8c and 8e magnetized generate a rotational force toward the centers of the magnetic pole teeth 11a and 11b of the third stator 11, and start rotating in the direction of arrow R in the figure. Then, in a state shown in FIG. This state is a state in which the first magnet 1 and the second magnet 8, that is, the output shaft 3 are rotated 11.25 degrees in the direction of the arrow R from the state of FIG.

  By sequentially switching the energization directions to the first coil 4 and the second coil 10 as described above, the first magnet 1 and the second magnet 8 that are the rotor, that is, the output shaft 3 are brought into the energization phase. It will rotate sequentially to the corresponding position.

  Here, the two-phase stepping motor constituted by sandwiching these magnets and coils from above and below is suitable for a high-efficiency stepping motor that can obtain high torque while being small and flat. State something.

  First, the two magnets, the first magnet 1 and the second magnet 8 having an annular shape, are shifted by an angle (PHm = 11.25 degrees) obtained by dividing 360 ° by twice the number P of the magnetic poles. It is fixed to the output shaft 3. Secondly, the surface in the vertical direction is divided with respect to the output shaft 3 which is the rotation center of the first magnet 1 and the second magnet 8 and is magnetized alternately in different poles. Thirdly, the first coil 4 and the second coil 10 are coaxially arranged outside (or inside) the outer peripheral surfaces of the first magnet 1 and the second magnet 8. Fourth, the first stator 5, the second stator 6, and the third stator 11 and the fourth stator 12 excited by the second coil 10 excited by the first coil 4, respectively, are the first. The magnet 1 and the second magnet 8 are opposed to a plane perpendicular to the axial direction, that is, an annular plane. Fifth, the magnetic pole teeth of the first stator 5, the second stator 6, the third stator 11, and the fourth stator 12 are constituted by comb teeth extending in the radial direction. Sixth, the magnetic pole teeth of the first stator 5 and the second stator 6, and the third stator 11 and the fourth stator 12 are opposed to each other, and the second stator 6 and the second stator 6 4, the phase of the magnetic pole teeth of the stator 12 is shifted by an angle (PHs = 22.5 degrees) obtained by dividing 360 ° by the number of magnetic poles P. Seventh, the bearing 2, the bearing 9, and the ground plane 7 are made of a nonmagnetic material.

  Further, because of the above structure, the magnetic flux generated by energizing the first coil 4 crosses the first magnet 1 between the first stator 5 and the second stator 6, so that it works effectively. In addition, the magnetic flux generated by energizing the second coil 10 acts effectively because it crosses the second magnet 8 between the third stator 11 and the fourth stator 12. Further, since the first stator 5, the second stator 6, the third stator 11, and the fourth stator 12 are all configured in a comb-teeth shape extending in the radial direction, they are configured to extend in the axial direction. The dimension in the axial direction can be made smaller than that of the conventional one. In addition, since the magnet and the coil are arranged in a space having substantially the same height, the dimension in the axial direction can be made smaller than the method in which the magnet and the coil are stacked in the axial direction.

  In addition, since the stator magnetic pole teeth on the surfaces where the two excitation phases are joined are farthest apart (for example, the magnetic pole teeth 12a are arranged between the magnetic pole teeth 6a and 6b), there is less interference between the magnetic pole teeth, The maximum magnetic flux is generated and the minimum magnetic resistance is obtained, resulting in a large output. Further, since it is a two-phase stepping motor having two coils, the first coil 4 and the second coil 10, the control is easy and the electric circuit for driving can be simplified. Further, since each stator is provided with magnetic pole teeth at an equal pitch over the entire circumference, the area facing the magnet can be increased, and the magnetic flux of the magnet can be utilized to the maximum. In addition, since the bearings and plates in the vicinity of the magnet and the stator are all made of a non-magnetic material, the leakage magnetic flux from the magnetic circuit between the magnet and the stator is small and the efficiency is not lowered. In addition, one excitation phase has one set of stators, and the magnetic pole teeth are arranged around the entire circumference with the magnet from above and below, and the position where the driving force is generated (the position where the magnet and magnetic pole teeth face each other) ) Over the entire circumference, it is difficult to generate unnecessary lateral force when the driving force is converted into rotational torque, and vibration, noise, and rotation unevenness hardly occur as a stepping motor. Thereby, it becomes a stepping motor with good stop position accuracy.

  Further, in the first embodiment, since the output shaft, the bearing, and the spacer (the ground plane 7) are added to the minimum elements of the electromagnetic drive device such as the magnet, the stator, and the coil, the number of parts is small, and each is manufactured simply. Easy flat plate shape for low manufacturing costs. Furthermore, in the method of further stacking two-phase stepping motors in the axial direction in order to obtain even higher torque, the high-torque can be achieved while maintaining high efficiency by adopting the configuration of this embodiment with high efficiency as a base unit. It is easy to think of.

  FIG. 7 is a schematic side view showing the phase relationship between the magnet and the stator of the stepping motor according to the second embodiment of the present invention.

  The stepping motor according to the second embodiment of the present invention is different from the stepping motor according to the first embodiment in the group of the first stator 22 and the second stator 23, the group of the third stator 26 and the fourth stator 27. The phase of the magnetic pole teeth between the two sets is shifted by an angle PHs obtained by dividing 360 ° by twice the number of poles P (= 16), and the first magnet 21 and the second magnet 25 are joined to the output shaft. The difference is that the phases of the magnetized portions are the same. Therefore, since all parts other than this phase are common, description of the configuration and operation is omitted.

  As shown in FIG. 7, when the upper unit and the lower unit are joined, the magnetic pole teeth 23a, 23b,... Of the second stator 23 and the magnetic pole teeth 27a, 27b,. It is displaced in the direction. The phase of the magnetization angle of the first magnet 21 and the second magnet 25 is the same. Here, O is the angle pitch between the magnetic pole teeth of the stator and M is the angle of the magnetized width of the magnet. As in Example 1, O is 360 × 2 / P, which is 45 degrees here. M is 360 / P, which is 22.5 degrees here. Therefore, PHs is O / 4, which is 11.25 degrees. Reference numeral 24 denotes a ground plane.

  Since the two magnets are joined to the single output shaft 3 in the same phase as in the second embodiment, the positioning portion of the shaft and each magnet can be easily configured, and it is difficult to produce defects in manufacturing. There are advantages. Specifically, for example, the magnetization phase of the magnet is determined by a semicircular protrusion on the outer periphery of the press-fit portion. Then, a circular projection on a plane perpendicular to the axis of the press-fitting part is set as a positioning on the joining jig. At that time, the projections of the press-fit portions of the first magnet 21 and the second magnet 25 are set in accordance with the same groove of the joining jig, and then the output shaft 3 is inserted into the hole of the press-fit portion and joined. To do. That is, since the circular protrusions of the press-fitting portion are set in the same groove, the two magnets 21 and 25 can be joined to the output shaft 3 with high accuracy and the same magnetization phase.

  A two-phase stepping motor constructed by sandwiching these magnets and coils from above and below in the same manner as in FIG. 2 is suitable as a high-efficiency stepping motor capable of obtaining high torque while being small and flat. It is described that this is a simple configuration.

  First, the two magnets of the first magnet 21 and the second magnet 25 having an annular shape are fixed to the output shaft 3 with the same magnetization phase. Second, the surface in the vertical direction is divided with respect to the output shaft 3 which is the rotation center of the first magnet 21 and the second magnet 25 and is magnetized alternately in different poles. Thirdly, a first coil (not shown) and a second coil (not shown) are arranged coaxially outside the outer peripheral surfaces of the first magnet 21 and the second magnet 25. Fourth, the first stator 22, the second stator 23 excited by a first coil (not shown), the third stator 26 and the fourth stator 27 excited by a second coil (not shown) are provided. Each of the first magnet 21 and the second magnet 25 is opposed to a plane perpendicular to the axial direction, that is, an annular plane. Fifth, the magnetic pole teeth of the first stator 22, the second stator 23, the third stator 26, and the fourth stator 27 are constituted by comb teeth extending in the radial direction. Sixth, the magnetic pole teeth of the first stator 22 and the second stator 23, and the third stator 26 and the fourth stator 27 are opposed to each other, and the second stator 23 and the second stator 23 4, the phase of the magnetic pole teeth of the stator 27 is shifted by an angle obtained by dividing 360 ° by twice the number of magnetic poles of the first and second magnets 21 and 25.

  In addition, because of the structure described above, the magnetization phases of the two magnets can be made completely coincident with each other, and a decrease in rotational position accuracy due to this misalignment can be prevented. A magnetic flux generated by energizing a first coil (not shown) acts effectively because it crosses the first magnet 21 between the first stator 22 and the second stator 23. Further, the magnetic flux generated by energizing the second coil (not shown) crosses the second magnet 25 between the third stator 27 and the fourth stator 26, and thus acts effectively. Further, since the first stator 22, the second stator 23, the third stator 26, and the fourth stator 27 are all configured in a comb-teeth shape extending in the radial direction, they are configured to extend in the axial direction. The dimension in the axial direction can be made smaller than that of the conventional one. In addition, since the two-phase stepping motor includes two coils, a first coil (not shown) and a second coil (not shown), the control is easy and the electric circuit for driving can be simplified.

  Furthermore, since each stator is provided with magnetic pole teeth at a uniform pitch over the entire circumference, the area facing the magnet can be increased, and the magnetic flux of the magnet can be utilized to the maximum. Furthermore, one excitation phase has one set of stators, and the magnetic pole teeth are arranged on the entire circumference with the magnet sandwiched in the vertical direction, and the position where the driving force is generated (the position where the magnet and the magnetic pole teeth face each other) ) Over the entire circumference, it is difficult to generate unnecessary lateral force when the driving force is converted into rotational torque, and vibration, noise, and rotation unevenness hardly occur as a stepping motor. Thereby, it becomes a stepping motor with good stop position accuracy.

  FIG. 8 is a schematic side view showing the phase relationship between the magnet and the stator, which are components of the stepping motor according to the third embodiment of the present invention.

  The stepping motor according to the third embodiment of the present invention is different from the stepping motor according to the first embodiment in the set of the first stator 32 and the second stator 33, the set of the third stator 36 and the fourth stator 37. The phases of the magnetic pole teeth between the two sets are made the same, and the phase of the magnetized portion when the first magnet 31 and the second magnet 35 are joined to the output shaft 3 is set to 360 °. The difference is that the angle PHm is divided by 2 times that of 16). Therefore, since all parts other than this phase are common, description of the configuration and operation is omitted.

  As shown in FIG. 8, when the upper unit and the lower unit are joined, the magnetic pole teeth 33a, 33b,... Of the second stator 33 and the magnetic pole teeth 37a, 37b,. Yes. The phase of the magnetization angle of the first magnet 31 and the second magnet 35 is shifted by an angle obtained by dividing 360 ° by twice the number of magnetic poles. Here, O is the angle pitch between the magnetic pole teeth of the stator and M is the angle of the magnetized width of the magnet. O is 360 × 2 / P as in Example 1, and is 45 degrees here. M is 360 / P, which is 22.5 degrees here. Therefore, PHm is O / 4, which is 11.25 degrees.

  A two-phase stepping motor constructed by sandwiching these magnets and coils from above and below in the same manner as in FIG. 2 is suitable as a high-efficiency stepping motor capable of obtaining high torque while being small and flat. It is described that this is a simple configuration.

  First, the two magnets of the annular first magnet 31 and the second magnet 35 are fixed to the output shaft by shifting the phase by an angle obtained by dividing 360 degrees by twice the number of the magnetic poles. It is that. Second, the plane perpendicular to the axis that is the rotation center of the first magnet 31 and the second magnet 35 is divided and magnetized alternately in different poles. Thirdly, the first coil (not shown) and the second coil (not shown) are arranged coaxially outside the outer peripheral surfaces of the first magnet 31 and the second magnet 35. Fourth, the first stator 32, the second stator 33 excited by a first coil (not shown), the third stator 36, and the fourth stator 37 excited by a second coil (not shown). Each of the first magnet 31 and the second magnet 35 is opposed to a plane perpendicular to the axial direction, that is, an annular plane. Fifth, the magnetic pole teeth of the first stator 32, the second stator 33, the third stator 36, and the fourth stator 37 are constituted by comb teeth extending in the radial direction. 6, the magnetic pole teeth of the first stator 32 and the second stator 33, and the third stator 36 and the fourth stator 37 are opposed to each other, and the second stator 33 and the fourth stator The phase of the magnetic pole teeth of the stator 37 is the same.

  By combining the phases of the second stator 33 and the fourth stator 37 identically, there is an advantage that the same press die can be used for manufacturing these stators. For example, positioning protrusions that can be fitted to each other on the back side of the magnetic pole teeth of the stator can be pressed, and by inserting these protrusions into the same hole provided in the ground plate 34, the phase of the magnetic pole teeth is completely the same. A stator set can be combined.

  In addition, because of the above structure, the magnetic flux generated by energizing the first coil (not shown) crosses the first magnet 31 between the first stator 32 and the second stator 33, so that it works effectively. To do. Further, the magnetic flux generated by energizing the second coil crosses the second magnet 35 between the third stator 36 and the fourth stator 37, so that it works effectively. Further, since the first stator 32, the second stator 33, the third stator 36, and the fourth stator 37 are all configured in a comb-teeth shape extending in the radial direction, they are configured to extend in the axial direction. The dimension in the axial direction can be made smaller than that of the conventional one.

  Furthermore, since the two-phase stepping motor is composed of two coils, a first coil (not shown) and a second coil (not shown), the control is easy and the electric circuit for driving can be simplified. Furthermore, since each stator is provided with magnetic pole teeth at a uniform pitch over the entire circumference, the area facing the magnet can be increased, and the magnetic flux of the magnet can be utilized to the maximum. In addition, one excitation phase has one set of stators, and the magnetic pole teeth are arranged around the entire circumference with the magnet from above and below, and the position where the driving force is generated (the position where the magnet and magnetic pole teeth face each other) ) Over the entire circumference, it is difficult to generate unnecessary lateral force when the driving force is converted into rotational torque, and vibration, noise, and rotation unevenness hardly occur as a stepping motor. Thereby, it becomes a stepping motor with good stop position accuracy.

  FIGS. 9 and 10 are views showing a stepping motor according to a fourth embodiment of the present invention, showing another example in which the coil arrangement of the stepping motor described in the first embodiment is different, and FIG. An exploded perspective view of a stepping motor having a different arrangement, FIG. 10 is an axial sectional view thereof. The description of the operation is the same as that in the first embodiment, and will not be repeated.

  9 and 10, reference numeral 51 denotes a disk-shaped magnet, which is divided into P parts in the circumferential direction on the surface perpendicular to the central axis (P is an even number, as in the first and second embodiments). 4 is P = 16), and is composed of magnetized portions magnetized alternately in N and S poles. In addition, a pole opposite to the front side inevitably appears on the back side of the magnetized surface. There are protrusions on the outer periphery that determine the magnetization phase. The first magnet 51 may be a plastic magnet formed by injection molding, but may be a magnet created by compression molding or the like. In this case, it is desirable to assemble the press-fit portion as a separate part because it is easily broken. Reference numeral 58 denotes a second magnet, which uses the same components as the first magnet 51, and therefore details thereof are omitted.

  Reference numeral 52 denotes a bearing, which is fixed to the second stator 56 for smoothly rotating and sliding an output shaft 53a of a rotor 53, which will be described later, and is made of, for example, an oil-impregnated sintered metal made of a nonmagnetic material. Further, it has a thrust receiving surface and faces a disk portion 53b of the rotor 53, which will be described later, with a slight gap to determine the axial position of the rotor 53. Since 59 is a bearing and uses the same components as the bearing 52, the details are omitted. 53 is a rotor composed of an output shaft 53a and a disk portion 53b. The first magnet 51 and the second magnet 58 are fixed by press-fitting or adhering, etc., with the magnetization phase determined by notches on the upper and lower sides of the outer ring portion. The bearing 52 and the bearing 59 are rotatably supported, and are made of a stainless material that outputs the rotational force. Reference numeral 54 denotes a first coil & bobbin, which is disposed at a substantially concentric position inside the first magnet 51 and is fixed to the second stator 56. The outer diameter is smaller than the inner diameter of the first magnet 51 and has a gap that does not interfere when the rotor 53 rotates. In the fourth embodiment, a conducting wire is wound around a bobbin made of an insulating material. Reference numeral 60 denotes a second coil and bobbin, which uses the same components as the first coil and bobbin 54, and therefore details thereof are omitted.

  Reference numeral 55 denotes a first stator, in which a comb-like shape constituting a magnetic pole extending in a plane perpendicular to the output shaft 53a and a hole for supporting the bearing 52 are manufactured by a punching press process or the like on a disk made of a soft magnetic material. Yes. Reference numeral 61 denotes a third stator, which uses the same components as the first stator 55, and therefore details thereof are omitted. Reference numeral 56 denotes a second stator, which is a disk made of a soft magnetic material and has a comb-tooth shape constituting a magnetic pole extending in a plane perpendicular to the output shaft 53a, a hole penetrating the output shaft, and rotation with the second stator 56. The notch of the rotation stop that determines the direction and the projection for determining the phase of the case 57 are manufactured by a stamping process, etc., and the inner periphery has a vertical wall cylindrical part manufactured by the drawing process, and the tip rotates. There are projections for phasing the direction, and the first stator 55 and the magnetic pole teeth are fixed in phase. By this standing wall cylindrical portion, the first stator 55 and the second stator 56 are connected with low magnetic resistance. Reference numeral 62 denotes a fourth stator, which uses the same components as the second stator 56, and therefore details thereof are omitted.

  Reference numeral 57 denotes a case, which is made of a non-magnetic material or a structure in which the magnetic resistance is increased, and has a phase determination for coupling the second stator 56 and the fourth stator 62 at both ends so as to have a predetermined phase. Has a notch.

  In the cross-sectional view of FIG. 10, as shown in the upper half of the stepping motor, the first stator 55 and the second stator 56 vertically move the first coil & bobbin 54 and the first magnet 51 on the inner peripheral portion thereof. The cross sections of the first stator 55 and the second stator 56 are fixed so that the distance between the surfaces perpendicular to the output shafts 53 of the first stator 55 and the second stator 56 is a predetermined distance. The Further, the phase of the magnetic pole teeth of each stator is a position where the magnetic pole teeth face each other across the first magnet 51. At the same time, the axial position of the first magnet 1 is also determined by the bearing 52 fixed to the first stator 55, so that the gap between the first magnet 1 and the first stator 5 and the first magnet 1 The gap with the second stator 6 is also a predetermined interval. Accordingly, when the first coil & bobbin 54 is energized, the first stator 55 and the second stator 56 around it are excited, and an N pole or an S pole is generated at the magnetic pole teeth. The poles generated in each stator are opposite to each other.

  Next, on the opposite side of the disk portion 53b of the rotor 53, a line symmetrical arrangement with the upper side of the stepping motor is made as shown in FIG. 10, that is, the second magnet 58 and the second coil & bobbin. A third stator 61 and a fourth stator 62 sandwiching 60 from above and below are disposed concentrically with the bearing 59 and fixed to the case 57. Detailed description is omitted.

  Here, the magnetic circuit in the upper unit will be described with reference to the cross-sectional view of FIG.

  When the first coil 54 on the inner periphery is energized, a magnetic flux is generated around the first coil 54, and is guided to the second stator 56 around the first coil 54 toward the outer periphery. Here, the comb-shaped magnetic pole teeth (not shown) of the second stator 56 are opposed to the thin first magnet 51, and toward the comb-shaped magnetic pole teeth (not shown) of the first stator 55 on the opposite side. Passes through the first magnet 51. Since the first magnet 51 is thin, the distance between the first stator 55 and the second stator 56 is small, and the first magnet 51 and the second stator 56, and the first magnet 51 and the first stator 55 Is the minimum distance between the rotating body and the stationary body, and since this is short, the magnetic loss in this portion is small. The magnetic flux that has passed through the first magnet 51 is guided to the first stator 55 and reaches the periphery of the first coil 54. Since the first stator 55 and the second stator 56 are connected at the cylindrical upper portion of the inner peripheral portion, the magnetic circuit is closed and no leakage magnetic flux is generated. Further, since the rotor 53 is a nonmagnetic material, there is no leakage magnetic flux. Since each stator is a soft magnetic material such as SUY having a low magnetic resistance, the magnetic loss in this portion is also small. Therefore, even if the current flowing through the coil is reduced, a large amount of magnetic flux can be generated, so that the output is high while being thin. Since the lower unit also has a symmetric structure, it has exactly the same function and will not be described.

Next, in the fourth embodiment, an example of a specific assembly order is shown.
1) Insert and fix the second stator 56 and the first coil & bobbin 54 in this order on the bearing 52.
2) Insert the unit from above the rotor 53. The rotor 53 is rotatable.
3) The first magnet 51 is fixed to the upper side of the outer ring portion of the rotor 53.
4) The first stator 55 is fixed to the second stator 56 and the bearing 52.
5) The case 57 is fixed to the first stator 55.

In the above 1) to 5), the bearing 52, the first and second stators 55 and 56, the first coil & bobbin 54, and the case 57 are integrated, and the rotor 53 and the first magnet 51 are mutually connected. And can be moved in the axial direction by a predetermined gap between each stator and magnet.
6) The fourth stator 62 and the second coil & bobbin 60 are inserted into the bearing 59 in this order and fixed.
7) Insert the unit from the lower side of the rotor 53. The rotor 53 is rotatable.
8) The second magnet 58 is fixed to the lower side of the outer ring portion of the rotor 53.
9) The third stator 61 is fixed to the fourth stator 62, the bearing 59, and the case 57.

  The bearing 59, the third and fourth stators 61 and 62, the second coil & bobbin 60, and the case 57 are integrally fixed to the case 57 by the above 6) to 9). As a result, from 1) The first and second magnets 51 and 58 fixed to the rotor 53 are rotatably combined with each stator fixed to the case 57 by 9) while having a predetermined gap.

  Next, the phase of the magnetic pole teeth of each stator will be described.

  The phases of the pole teeth of the first stator 55 and the second stator 56 are the same, and the phases of the magnetic pole teeth of the third stator 61 and the fourth stator 62 are also the same. Here, there are combinations between the two stator sets and the two magnets as in the first to third embodiments, and there are respective merits as in the first to third embodiments. Therefore, the detailed description is abbreviate | omitted.

  Next, the reason why the fourth embodiment is a high-efficiency stepping motor that generates high torque while being thin will be described. In the fourth embodiment, the magnet is disposed on the outermost diameter side of the stepping motor. It can be a magnet with a large diameter. Therefore, even when the same electromagnetic force is generated, a larger torque can be obtained as compared with the case where the magnet is arranged on the inner diameter side. In addition, since the coil is arranged on the inner diameter side, the total resistance value becomes smaller because the length of the conducting wire is short when the diameter of the conducting wire and the number of turns of the winding are the same as compared with the case where the coil is arranged on the outer side. That is, if the resistance value is the same, a thinner wire can be used, and the coil can have a larger number of turns. As a result, a larger magnetic flux can be generated and a high torque stepping motor can be obtained. it can.

  Here, the two-phase stepping motor configured by sandwiching the magnet and the coil as described above and further stacking them with a small size and a flat shape is suitable as a highly efficient stepping motor that can obtain high torque. State something.

  First, the two magnets of the annular first magnet 51 and the second magnet 58 are fixed to the rotor 53 by shifting the phase by an angle obtained by dividing 360 degrees by twice the number of the magnetic poles. It is that. Second, the plane perpendicular to the axis that is the rotation center of the first magnet 51 and the second magnet 58 is divided and magnetized alternately in different poles. Third, the first coil is coaxially arranged inside the inner peripheral surfaces of the first magnet 51 and the second magnet 58 (or may be outside the outer peripheral surface). Fourth, the first stator 55, the second stator 56, the third stator 61, and the fourth stator 62 excited by the first coil are connected to the shafts of the first magnet 51 and the second magnet 58, respectively. It is facing the surface perpendicular to the direction, that is, an annular plane. Fifth, each magnetic pole tooth of the first stator 55, the second stator 56, the third stator 61, and the fourth stator 62 is constituted by comb teeth extending in the radial direction. Sixth, the magnetic pole teeth of the first stator 55 and the second stator 56, and the third stator 61 and the fourth stator 62 are opposed to each other, and the second stator 56 and the second stator 56 are opposed to each other. That is, the phase of each magnetic pole tooth of the fourth stator 62 is the same.

  Further, because of the above structure, the magnetic flux generated by energizing the first coil and bobbin crosses the first magnet 51 between the first stator 55 and the second stator 56, and thus acts effectively. . The magnetic flux generated by energization of the second coil & bobbin crosses the second magnet 58 between the third stator 61 and the fourth stator 62, and thus acts effectively. The first stator 55, the second stator 56, the third stator 61, and the fourth stator 62 are all configured in a comb-teeth shape extending in the radial direction, and thus are configured to extend in the axial direction. The dimension in the axial direction can be made smaller than that of the conventional one.

  Further, in the fourth embodiment, the first magnet 51 is generated on the outer diameter side, and the first coil & bobbin is arranged on the inner peripheral side of the first magnet 51. Therefore, the first magnet 51 is generated in the first magnet 51 having a large diameter. The torque becomes larger, and the first coil & bobbin having a smaller diameter can perform winding with a larger number of turns, so that higher torque can be obtained in total.

  By using the stepping motor having the configuration of the first to fourth embodiments described above, the stepping motor can be configured to be thin, can generate a high torque, has good assemblability, and can be manufactured at low cost. Is to do. Furthermore, not only high torque but also vibration, noise, and rotation unevenness are small, and a high-function stepping motor with good stop position accuracy can be obtained.

  The stepping motor of the present invention is thin and capable of generating high torque, and has effects such as less vibration, noise and rotation unevenness, and high assembly accuracy, and is useful as a drive source for a light amount adjusting device, a camera, and the like. .

It is a disassembled perspective view of the stepping motor concerning Example 1 of the present invention. It is sectional drawing of the axial direction of the stepping motor of FIG. It is a schematic diagram of the side view which shows the phase relationship of the magnet and stator of the stepping motor of FIG. It is a schematic diagram of the side view which shows the state which switched the electricity supply to the coil from the state of FIG. 3, and rotated the magnet 11.25 degree | times. It is a schematic diagram of the side view which shows the state which switched the electricity supply to the coil from the state of FIG. 4, and rotated the magnet 11.25 degree | times. FIG. 6 is a schematic side view showing a state in which the magnet is rotated 11.25 degrees by switching energization to the coil from the state of FIG. 5. It is the schematic diagram of the side view which shows the phase relationship of the magnet of the stepping motor concerning Example 2 of this invention, and a stator. It is a schematic diagram of the side view which shows the phase relationship of the magnet of the stepping motor concerning Example 3 of this invention, and a stator. It is a disassembled perspective view of the stepping motor concerning Example 4 of the present invention. It is sectional drawing of the axial direction of the stepping motor of FIG. It is sectional drawing of the axial direction of the conventional stepping motor. It is a fragmentary sectional view which shows typically the state of the magnetic flux of the stator of the stepping motor of FIG. It is typical sectional drawing which shows the other structural example of the conventional solid cylindrical shape stepping motor. It is a block diagram of the conventional thin coin-shaped motor. It is sectional drawing which shows the mode of the magnetic flux of the motor shown in FIG. It is a perspective view which shows the conventional thin exposure adjustment apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st magnet 2 Bearing 3 Output shaft 4 1st coil 5 1st stator 6 2nd stator 7, 24 Ground plane 8 2nd magnet 9 Bearing 10 2nd coil 11 3rd stator 12 4th Stator 51 First magnet 52 Bearing 53 Rotor 54 First coil 55 First stator 56 Second stator 57 Case 58 Second magnet 59 Bearing 60 Second coil 61 Third stator 62 Fourth stator

Claims (3)

A first magnet and a second magnet that are disk-shaped and have a surface perpendicular to the central axis divided in the circumferential direction and alternately magnetized to different poles, and the first magnet is magnetized A first stator facing the surface, a second stator on a surface opposite to the first stator across the first magnet and parallel to the first stator, and the first stator A first coil that is substantially concentric with the magnet and sandwiched between the first stator and the second stator and that excites the first stator and the second stator, and magnetization of the second magnet A third stator facing the formed surface, a fourth stator on a surface opposite to the third stator across the second magnet and parallel to the third stator; 2 and substantially concentric with the magnet And a second coil that excites the third stator and the fourth stator, and the first magnet and the second magnet are spaced apart from each other by a predetermined distance. And a stepping motor having an output shaft that rotatably holds them as a unit ,
The first to fourth stators each have a number of magnetic pole teeth that is ½ of the number of magnetic poles P of the first and second magnets,
A combination of the first and second stators, in which the magnetic pole teeth are arranged to face each other with the first magnet interposed therebetween, is a first stator assembly, and each magnetic pole tooth is a positive electrode with the second magnet interposed therebetween. When the combination of the third and fourth stators arranged on the other side is a second stator set, the first stator set and the second stator set are rotated around the phase where the magnetic pole teeth are provided. The first magnet and the second magnet are shifted by an angle of 360 ° / P in the direction, and the magnetization phase of the first magnet and the second magnet is shifted in the circumferential direction by an angle of 360 ° / 2P to the output shaft. Stepping motors characterized by being fixed to each other . A first magnet and a second magnet that are disk-shaped and have a surface perpendicular to the central axis divided in the circumferential direction and alternately magnetized to different poles, and the first magnet is magnetized A first stator facing the surface, a second stator on a surface opposite to the first stator across the first magnet and parallel to the first stator, and the first stator A first coil that is substantially concentric with the magnet and sandwiched between the first stator and the second stator and that excites the first stator and the second stator, and magnetization of the second magnet A third stator facing the formed surface, a fourth stator on a surface opposite to the third stator across the second magnet and parallel to the third stator; 2 and substantially concentric with the magnet And a second coil that excites the third stator and the fourth stator, and the first magnet and the second magnet are spaced apart from each other by a predetermined distance. And a stepping motor having an output shaft that rotatably holds them as a unit,
The first to fourth stators each have a number of magnetic pole teeth that is ½ of the number of magnetic poles P of the first and second magnets,
A combination of the first and second stators, in which the magnetic pole teeth are arranged to face each other with the first magnet interposed therebetween, is a first stator assembly, and each magnetic pole tooth is a positive electrode with the second magnet interposed therebetween. Assuming that the combination of the third and fourth stators arranged with respect to each other is a second stator set, the first stator set and the second stator set are 360 on the basis of the phase where the magnetic pole teeth are provided. A stepping motor characterized in that the first magnet and the second magnet are fixed to the output shaft with the same phase while being shifted by an angle of ／/ 2P . A first magnet and a second magnet that are disk-shaped and have a surface perpendicular to the central axis divided in the circumferential direction and alternately magnetized to different poles, and the first magnet is magnetized A first stator facing the surface, a second stator on a surface opposite to the first stator across the first magnet and parallel to the first stator, and the first stator A first coil that is substantially concentric with the magnet and sandwiched between the first stator and the second stator and that excites the first stator and the second stator, and magnetization of the second magnet A third stator facing the formed surface, a fourth stator on a surface opposite to the third stator across the second magnet and parallel to the third stator; 2 and substantially concentric with the magnet And a second coil that excites the third stator and the fourth stator, and the first magnet and the second magnet are spaced apart from each other by a predetermined distance. And a stepping motor having an output shaft that rotatably holds them as a unit,
The first to fourth stators each have a number of magnetic pole teeth that is ½ of the number of magnetic poles P of the first and second magnets,
A combination of the first and second stators, in which the magnetic pole teeth are arranged to face each other with the first magnet interposed therebetween, is a first stator assembly, and each magnetic pole tooth is a positive electrode with the second magnet interposed therebetween. Assuming that the combination of the third and fourth stators arranged with respect to each other is a second stator assembly, the first stator assembly and the second stator assembly are combined in the same phase with magnetic pole teeth. The stepping motor is characterized in that the first magnet and the second magnet are fixed to the output shaft by shifting their phases in the circumferential direction by an angle of 360 ° / 2P .

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