JP4272075B2 - Stepping motor - Google Patents

Description

  The present invention relates to a stepping motor, and more specifically to an improvement in a magnetic circuit between a stator (stator) and a rotor (rotor).

  One well-known type of stepping motor is a claw pole type as shown in FIGS. 1 (a) and 1 (b). This can be said to be one of the most produced types, and the rotor is composed of a cylindrical permanent magnet 102 attached to a rotating shaft 101 as shown in FIG. The cylindrical permanent magnet 102 is magnetized in multi-poles at equal intervals in the circumferential direction. In this case, as the number of poles increases, the gap between the magnetic poles becomes narrower, making it difficult to completely magnetize the magnet. Usually, a number of poles of about 10 to 50 is used according to the outer dimensions of the rotor. The stator is composed of two sets of electromagnets including yokes 104 and 105 having a number of claw-shaped magnetic poles 103 formed by pressing from a steel plate and solenoid windings 106 and 107. The claw-shaped magnetic poles 103 form a number corresponding to the number of magnetic poles of the permanent magnet 102 and are called claw poles. The two sets of electromagnets are arranged such that the magnetic pole positions are shifted by a half of the magnetization pitch of the permanent magnets 102 in the rotation direction of the rotor to form a two-phase armature. In this type of stepping motor, the yokes 104 and 105 can be formed by pressing, the rotor can be formed by collectively magnetizing cylindrical magnets, and the solenoid windings 106 and 107 have high-speed windings. It has a configuration that is possible, has little waste in winding volume, has high productivity, and is suitable for mass production.

  On the other hand, as seen in Patent Document 1 and the like, there is a proposal of a configuration in which a solenoid winding, a cylindrical permanent magnet, and a solenoid winding are sequentially arranged in the axial direction. That is, as shown in FIGS. 2A and 2B, a cylindrical permanent magnet 108 having an outer peripheral surface divided into n in the circumferential direction and alternately magnetized to different poles is attached to the rotating shaft 116. The first solenoid winding 109, the permanent magnet 108, and the second solenoid winding 110 are arranged in this order between two bearings 117 and 117 that support both ends of the rotating shaft 116. Then, the first outer magnetic pole 111 and the first inner magnetic pole 112 excited by the first solenoid winding 109 are opposed to the outer peripheral surface and the inner peripheral surface of one end of the permanent magnet 108, and the second solenoid winding 110 is excited. The second outer magnetic pole 113 and the second inner magnetic pole 114 are opposed to the outer peripheral surface and the inner peripheral surface on the other end side of the permanent magnet 108, and the two sets of magnetic circuits are connected by a connecting member 115.

  On the other hand, there is also a configuration in which an armature and a permanent magnet are used as a stator and an inductor is used as a rotor. For example, as seen in Patent Document 2, a permanent magnet magnetized in multiple poles is used as an rotor as an inductor. There are known ones that face each other with a gap in between. That is, the structure shown in FIG. 3 is adopted, 118 is an inductor tooth, 119 is a tooth, 120 is an armature winding, 121 is a yoke, 122 is a magnetic pole, and 123 is a permanent magnet. The arrow in the figure indicates the magnetization direction of the permanent magnet, and FIG. 3B is an explanatory view showing the tip portion of the tooth 119 (X in FIG. 3A) in an enlarged manner.

In this case, the rotor is constituted by an inductor made of a magnetic body on which inductor teeth 118 are formed. The stator includes an armature core in which six teeth 119 and a yoke 121 connecting them are integrated, and a three-phase (U, V, W) armature winding 120 concentratedly wound around the six teeth 119; Each arm 119 is constituted by an armature composed of a magnetic pole 122 provided at the tip of each tooth 119. Since one permanent magnetic pole 122 composed of six poles is composed of six permanent magnets 123 so that adjacent ones are different from each other, it is not necessary to process inductor teeth on the stator side. The rotor is rotatably supported by a bearing (not shown).
JP-A-11-41902 JP 2002-369478 A

  However, such conventional stepping motors have the following problems. In the stepping motor configured as shown in FIG. 1, the magnetic pole 103, the solenoid windings 106 and 107, and the yokes 104 and 105 are arranged concentrically around the permanent magnet 102, and the rotor magnetic circuit and the stator magnet are arranged in the radial direction. Circuits are stacked, and when the outer diameter is reduced, there is a drawback that it is difficult to distribute the necessary radial dimension to each component. The same applies to the case of FIG. 3, and it is difficult to reduce the outer diameter because the components are arranged in the radial direction.

  Further, the claw pole magnetic pole 103 in FIG. 1 is formed by cutting out a part of the yoke constituting the magnetic circuit and narrowing the magnetic circuit, so that the magnetic flux that can be used by the magnetic saturation at the base portion is reduced. Maximum value is limited. Therefore, when the outer diameter is limited, there is a drawback that it is difficult to secure a necessary and sufficient cross-sectional area of the magnetic circuit.

  In the configuration of FIG. 2, since the stator magnetic circuit and the rotor magnetic circuit are arranged in the axial direction, the difficulty of dimensional distribution in the radial direction for each component is reduced. For this reason, it is possible to use a permanent magnet having a larger diameter than that of the configuration of FIG. 1, and it is easy to increase the number of poles and obtain a large output torque. Further, since the rotor magnet is not included on the inner diameter side of the first solenoid winding 109 and the second solenoid winding 110, the inner diameter of the coil winding can be reduced to reduce the winding resistance per one turn of the coil. The magnetomotive force per unit copper loss can be increased.

  However, in this configuration, even if the magnetic flux for torque generation is increased by using a permanent magnet having a larger outer diameter, the outer magnetic poles 111 and 113 and the inner magnetic poles 112 and 114 are also the yokes constituting the magnetic circuit. Since the magnetic circuit is narrowed by cutting out a part thereof, there is a drawback that the maximum value of the magnetic flux that can be used is restricted by the magnetic saturation at the base part. Further, in this configuration, since a permanent magnet having a larger diameter than that in the configuration of FIG. 1 is used for the rotor, the inertia performance ratio of the rotor is increased, and as a result, the response of the motor at a high pulse rate is deteriorated. Since the magnetic poles 111 and 113 are exposed on the outer periphery, there is a drawback that the characteristics as a motor change if a magnetic material is disposed in the vicinity of the notch portion of the magnetic pole.

  SUMMARY OF THE INVENTION The present invention solves the above-described problems, and its object is to increase the output torque per unit copper loss under the condition of limiting the motor geometry, particularly the motor outer diameter. It is an object of the present invention to provide a stepping motor that has a small inertia ratio and can be preferably applied to miniaturization.

  In order to achieve the above object, a stepping motor according to the present invention has two large and small cylindrical yokes concentrically overlapped, one end is magnetically connected and the other end is magnetically opened, and the magnetic A solenoid winding is arranged on the side of the general connection end, and a permanent magnet is annularly arranged on the magnetic open end side so as to be in magnetic contact with the inner circumference of the outer cylindrical yoke. The part is used as a first magnetic circuit by magnetizing in multiple poles in the direction, and the first magnetic circuit and a second magnetic circuit having the same configuration are placed in a predetermined gap with the magnetic open end sides facing each other. Arranged as an armature, and inside the permanent magnet of each of the first magnetic circuit and the second magnetic circuit, there is an outer circumferential inductor whose radial magnetic resistance changes periodically in the circumferential direction. These inductors are supported by a rotating shaft And trochanter, and configured to include a magnetic circuit for magnetically coupling with a gap between the inner diameter or the axial side surface of the inductor and the inner cylindrical yoke.

Further, it is preferable that the inductor of the first magnetic circuit and the inductor of the second magnetic circuit are magnetically integrated. Further, the rotating shaft may be made of a soft magnetic material, and the magnetically integrated inductor may be supported by the rotating shaft, and the outer cylindrical yoke of the first magnetic circuit and the second magnetic circuit may be supported. The outer cylindrical yoke of the circuit can be integrally formed of a soft magnetic material.
(Magnetic circuit according to the present invention)
FIG. 4 is a cross-sectional view of a motor for explaining a magnetic circuit according to the present invention. FIGS. 4 (a) and 4 (b) show a cut surface in the radial direction, and FIG. 4 (c) shows FIG. Fig. 4 (d) shows the BB cut surface in Fig. 4 (b).

  In the figure, 1 is an outer cylindrical yoke having a large diameter, 2 is an inner cylindrical yoke having a small diameter, and 3 is an annular plate yoke that magnetically connects the outer cylindrical yoke 1 and the inner cylindrical yoke 2. Each of these yokes is formed of a soft magnetic material. Reference numeral 4 denotes a drive coil using solenoid windings. Reference numeral 5 denotes a cylindrical permanent magnet, which is fixed so as to be in magnetic contact with the inner diameter of the outer cylindrical yoke 1 and is magnetized to different poles in the circumferential direction. In this example, it is divided into 12 in the circumferential direction. It is magnetized alternately on different poles. The arrow shown in the permanent magnet 5 is the direction of magnetization. Reference numeral 6 denotes an inductor, and six inductor teeth are processed into a soft magnetic material so that the radial magnetic resistance periodically changes in the circumferential direction. The inner diameter of the inductor 6 and the outer periphery of the inner cylindrical yoke 2 have a magnetic circuit that is magnetically coupled via a gap. In addition, the arrows shown on the outside of the inductor 6, the inner cylindrical yoke 2, the annular plate yoke 3, and the outer cylindrical yoke 1 indicate the magnetic fluxes in the respective portions.

  When the inductor teeth of the inductor 6 are located at the center between the adjacent magnetic poles of the permanent magnet 5, as shown in FIG. As shown in FIG. 4 (c), it flows in the direction perpendicular to the paper surface between the cylindrical yoke 1 and one magnetic pole of the permanent magnet 5, the inductor teeth of the inductor 6, the other magnetic pole of the permanent magnet 5, It circulates through the path of the outer cylindrical yoke 1. For this reason, the magnetic flux by the permanent magnet 5 flowing in the path of the inner cylindrical yoke 2, the annular plate yoke 3, and the outer cylindrical yoke 1 becomes zero.

  As shown in FIGS. 4B and 4D, when the inductor teeth of the inductor 6 face one of the magnetic poles of the permanent magnet 5, the magnetic flux collected by the inductor teeth having low magnetic resistance at the adjacent magnetic poles. As shown in FIG. 4 (d), the magnetic flux resulting from these differences flows into the flow surrounding the drive coil 4, that is, in the path of the inner cylindrical yoke 2, the annular plate yoke 3, and the outer cylindrical yoke 1. Flowing. 4 (a) and 4 (c), when the inductor is 15 degrees mechanical angle in the right direction and the angle formed by a pair of adjacent magnetic poles of the permanent magnet 5 is 360 degrees, the electrical angle. In this state, it is rotated 90 degrees to the right.

Since most of the magnetic flux flows in a plane perpendicular to the axis inside the permanent magnet 5 and the inductor 6, even if the outer diameter is limited, by setting these axial dimensions large, an outer cylindrical shape is obtained. A magnetic flux having a maximum value that just saturates the yoke 1 or the inner cylindrical yoke 2 is caused to flow through the path of the inner cylindrical yoke 2, the annular plate yoke 3, and the outer cylindrical yoke 1, which is a flow surrounding the drive coil 4. Can do. In addition, the inductor 6 shown in FIG. 4 has an integral shape in which each inductor tooth is connected on the inner diameter side, but the same effect can be obtained even if each inductor tooth is magnetically separated. Can do.
(Configuration of stepping motor)
As the stepping motor, two sets of magnetic circuits shown in FIG. 4 can be used, and the inductor 6 side can be arranged in the axial direction facing each other to form a two-phase motor. At this time, it is necessary for the two magnetic circuits to be able to realize the flow of magnetic flux shown in FIG. 4 independently without interference. For example, a magnetic air gap is provided between the two magnetic circuits. That's fine.

  As long as a sufficient magnetic gap can be secured between the two magnetic circuits between the outer cylindrical yokes 1, the inductor 6 and the inner cylindrical yoke 2 may be magnetically coupled. 4 can be realized. Further, if a sufficient magnetic gap can be secured both between the inductors 6 and between the inner cylindrical yokes 2, the outer cylindrical yokes 1 are magnetically coupled to each other. Can also realize the flow of magnetic flux shown in FIG.

  With this configuration, in the present invention, it is not necessary to provide a cutout in the cylindrical yoke in order to configure the magnetic pole, and the cross-sectional areas of the two cylindrical yokes 1 and 2 having different diameters are the same as those of the cylindrical yoke 1, 2 is set so as to be magnetically saturated at the maximum value of the magnetic flux flowing through the magnetic circuit formed by 2. For this reason, under the condition that the outer diameter of the outer cylindrical yoke 1 is defined, the solenoid winding (drive coil 4) has the maximum outer diameter limited to the inner diameter of the outer cylindrical yoke 1, and the inner diameter is the inner cylindrical shape. The minimum value is limited to the outer diameter of the yoke 2.

  That is, the magnetomotive force per unit copper loss is maximized in the solenoid winding under the conditions that define the motor outer diameter and the winding width of the solenoid winding. Since the permanent magnet 5 is fixedly disposed on the inner periphery of the outer cylindrical yoke 1, the outer diameter of the permanent magnet 5 is the maximum diameter that can be used under the condition that defines the motor outer diameter. Therefore, a motor having an extremely large output torque per unit copper loss can be obtained.

  Furthermore, since the inductor 6 constituting the rotor is arranged inside the permanent magnet 5 and has inductor teeth, it is compared with other conventional configurations in which a permanent magnet having high inertia is used as the rotor in the first place. Thus, the inertia performance ratio of the rotor can be reduced, and therefore the deterioration of the motor response due to the drive signal having a high pulse rate can be prevented.

  In addition, regarding the magnetic flux flowing in the radial direction, the cross-sectional area of the magnetic path decreases and the magnetic flux density increases as it approaches the inner diameter side, but a magnetic material having a high saturation magnetic flux density can be used for the inductor 6. By doing so, it is possible to design to avoid magnetic saturation.

  In the stepping motor according to the present invention, the magnetomotive force per unit copper loss is maximized in the solenoid winding under the conditions defining the motor outer diameter and the winding width of the solenoid winding. And since a permanent magnet is fixed and arrange | positioned at the inner periphery of an outer side cylindrical yoke, the outer diameter of a permanent magnet becomes the largest diameter which can be utilized on the conditions which prescribed | regulated the motor outer diameter. Therefore, a motor having an extremely large output torque per unit copper loss can be obtained, and the rotating element is an inductor made of a soft magnetic material. The inertia ratio can be reduced. As a result, it can be preferably applied to miniaturization.

(First embodiment)
5 to 7 show a first embodiment of the present invention. In the present embodiment, the stepping motor has a configuration in which two sets of magnetic circuits shown in FIG. 4 are connected, and the two inductors are arranged in the axial direction so that the inductor sides face each other. .

  5-7, 7 is the outer cylindrical yoke that forms the first magnetic circuit, 8 is the inner cylindrical yoke that forms the first magnetic circuit, and 9 is a magnetic coupling between the outer cylindrical yoke 7 and the inner cylindrical yoke 8. 10 is an outer cylindrical yoke that forms a second magnetic circuit, 11 is an inner cylindrical yoke that forms a second magnetic circuit, and 12 is an outer cylindrical yoke 10 and an inner cylindrical yoke 11. An annular plate yoke that is magnetically coupled. These are made of a soft magnetic material.

  Reference numerals 13 and 14 denote solenoid windings, which are generally formed by winding a coated copper wire around a resin bobbin. The solenoid windings 13 and 14 are attached to the annular plate yoke 9 of the first magnetic circuit and the annular plate yoke 12 of the second magnetic circuit, respectively. The inner diameter of the solenoid windings 13 and 14 is set to fit with the outer diameter of the inner cylindrical yokes 8 and 11, and the outer diameter is set to fit with the inner diameter of the outer cylindrical yokes 7 and 10.

  For the outer cylindrical yokes 7 and 10 and the inner cylindrical yokes 8 and 11, the inner diameter, outer diameter, that is, the cross-sectional area is set to a cross-sectional area that is magnetically saturated at the maximum value of the magnetic flux flowing through the magnetic circuit. As for the elements concerned, the outer diameter (motor outer diameter) of the outer cylindrical yokes 7 and 10 is originally defined, and is secured between the outer diameter of the rotating shaft 20 and the inner diameters of the inner cylindrical yokes 8 and 11 outside thereof. The inner diameters of the inner cylindrical yokes 8 and 11 corresponding to the air gap to be obtained, and the outer and inner diameters of the solenoid windings 13 and 14 are the maximum value and the minimum value under the conditions in which these are predetermined. For this reason, the solenoid windings 13 and 14 can be configured to exhibit the maximum magnetomotive force per unit copper loss per winding width.

  The outer cylindrical yokes 7 and 10 shown in FIG. 5 are provided with notches 7a and 10a for drawing out the terminals of the solenoid windings 13 and 14 to the outside in the radial direction. In this case, it is necessary to consider the influence of the notches 7a and 10a in determining the inner diameter of the outer cylindrical yokes 7 and 10. In the case of pulling out in the axial direction, the annular plate yokes 9 and 12 are notched or drilled, so that the notches 7a and 10a are not necessary.

  Reference numerals 15 and 16 denote permanent magnets that are n-divided in the circumferential direction and are alternately magnetized to different poles, and are respectively fixed in contact with the inner diameters of the outer cylindrical yokes 7 and 10. For this reason, a flexible magnet or an arc segment shaped sintered magnet can be used as the magnet material. In addition, it is not necessary to integrally connect in the circumferential direction, and there may be a gap between the magnets forming the n-divided magnetic poles. In this embodiment, the permanent magnets 15 and 16 are magnetized to 8 poles as shown in FIGS. 7A and 7B, and the arrows in the figure indicate the magnetization directions of the permanent magnets.

  The positional relationship between the magnetizations of the two permanent magnets 15 and 16 is set to a shift position, and if the magnetization is divided into n, the position is shifted to a mechanical angle of 180 / n degrees in the circumferential direction. Here, since the magnetization is divided into 8 parts, it is shifted by 22.6 degrees, and if the angle between adjacent magnetic poles is 360 degrees in electrical angle, the positional relationship is shifted by 90 degrees in electrical angle.

  A yoke coupling member 21 made of a non-magnetic material maintains the distance between the first magnetic circuit and the second magnetic circuit and reduces magnetic coupling. Further, by providing protrusions and notches on the yoke coupling member 21 and the outer cylindrical yokes 7 and 10, the two permanent magnets 15 and 16 can be positioned so as to be shifted by 90 degrees in electrical angle.

  Reference numerals 17 and 18 denote inductors made of a soft magnetic material, and are coupled to the rotary shaft 20 via a non-magnetic shaft connecting member 19. The rotating shaft 20 is preferably formed from a non-magnetic material, but may be a soft magnetic material. By forming the rotating shaft 20 from a soft magnetic material, the magnetic coupling between two magnetic circuits arranged in the axial direction is slightly increased. There is a possibility of making it happen, but it can be used without causing a significant loss. The inductors 17 and 18 generally have n / 2, that is, four inductor teeth in the present embodiment, and the inductor teeth of the inductor 17 and the inductor 18 are in the same phase positional relationship in the circumferential direction. It has become.

  According to such a configuration, the magnetomotive force per unit copper loss is maximized in the solenoid windings 13 and 14 under the conditions defining the motor outer diameter and the winding width of the solenoid windings 13 and 14. Since the permanent magnets 15 and 16 are fixedly disposed on the inner circumference of the outer cylindrical yokes 7 and 10, the outer diameter of the permanent magnets 15 and 16 is the maximum available under the conditions that define the motor outer diameter. It becomes the diameter. Therefore, it is possible to obtain a motor having an extremely large output torque per unit copper loss, and the inductors 17 and 18 made of a soft magnetic material rotate. Therefore, compared with other conventional configurations in which a magnet is used as a rotor. The inertia ratio of the rotor can be reduced. As a result, it can be preferably applied to miniaturization.

In addition, about the two permanent magnets 15 and 16, you may set the positional relationship of magnetization to the in-phase direction without setting it as a shift | offset | difference position, In that case, the inductor teeth of the inductors 17 and 18 are electrically connected to the rotation direction. The same action and effect can be obtained by setting the positional relationship so that the angle is shifted by 90 degrees.
(Second Embodiment)
8 and 9 show a second embodiment of the present invention. In the second embodiment, a configuration in which inductors of two magnetic circuits are integrated is adopted. Constituent elements similar to those of the first embodiment described above are denoted by the same reference numerals and description thereof is omitted.

That is, the outer cylindrical yokes 7 and 10 are mechanically coupled by the yoke coupling member 21 made of a nonmagnetic member. Accordingly, the inductors of the two magnetic circuits can be magnetically coupled. Reference numeral 22 denotes an inductor in which two magnetic circuit inductors are integrated. The inductor 22 is mechanically attached to the rotary shaft 20 via a shaft connecting member 23 made of a nonmagnetic material. Thereby, the number of parts can be reduced and assembly can be facilitated.
(Third embodiment)
10 and 11 show a third embodiment of the present invention. In the third embodiment, similarly to the second embodiment, two outer cylindrical yokes 7 and 10 aligned in the axial direction are mechanically coupled by a yoke coupling member 21 made of a nonmagnetic member. is doing. In this case, the inductors 24 of the two magnetic circuits and the inner cylindrical yokes 8 and 11 can be magnetically coupled, so that the magnetically integrated inductor 24 is rotated by a soft magnetic material. A configuration for directly attaching to the shaft 25 is adopted. Thereby, the rotating shaft 25 is also used as a magnetic circuit. In addition, the same code | symbol is attached | subjected to the component similar to 1st Embodiment mentioned above, and the description is abbreviate | omitted.

  Thus, since the inductor 24 is directly attached to the rotating shaft 25 made of a soft magnetic material, the inductor 24 can be formed by integral molding such as cutting, sintering, and lost wax. Moreover, the process which press-processes a steel plate, laminate | stacks, and magnetically integrates is also good.

By using the rotating shaft 25 as a magnetic circuit, the gap between the inductor and the rotating shaft 25 can be eliminated, and a more suitable configuration can be provided by reducing the diameter. The entire rotary shaft 25 may be formed of a soft magnetic material, or only the portion through which magnetic flux passes, for example, only the outer peripheral side of the shaft may be formed of a soft magnetic material.
(Fourth embodiment)
12 and 13 show a fourth embodiment of the present invention. In the fourth embodiment, a configuration is employed in which the inductor 17 and the inductor 18 are mechanically coupled by a nonmagnetic shaft connection member 19. The same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.

  In this case, it is possible to magnetically connect the outer cylindrical yoke, and the outer cylindrical yoke 26 is formed by integrating the outer cylindrical yokes of the two magnetic circuits. Thus, the mechanical strength can be increased by forming the outermost yoke with a soft magnetic material in an integral structure. In addition, leakage of magnetic flux to the outside can be reduced, and the magnetic influence from the outside can be made difficult.

  Here, it is necessary to reduce the magnetic coupling between the inductor 17 and the inductor 18. For this reason, as shown in FIG. 13, the inductor teeth of the inductor 17 and the inductor 18 are set at positions where the electrical angle is shifted by 90 degrees in the circumferential direction. The permanent magnets 15 and 16 can be formed of one magnet because the magnetized positions are in the same phase in the circumferential direction. Therefore, there is an advantage in reducing the number of parts, and assembly can be facilitated.

It is a perspective view which shows the prior art example of a stepping motor, (a) fractures | ruptures and shows the inside, (b) shows a rotor independently. It is a perspective view which shows the other conventional example of a stepping motor, (a) shows each part disassembled, (b) fractures | ruptures and shows the inside. It is sectional drawing (a) which shows the other conventional example of a stepping motor, (b) expands and shows a space | gap part. It is sectional drawing of the motor explaining the magnetic circuit which concerns on this invention, (a), (b) shows the cut surface in radial direction, (c), (d) shows the cut surface in an axial direction. 1 is a perspective view showing a preferred embodiment of a stepping motor according to the present invention. It is sectional drawing which cut | disconnected the step motor of FIG. 5 about the axial direction. It is sectional drawing which cut | disconnected the step motor of FIG. 5 about the radial direction, (a) is a part of an AA line, (b) is a part of a BB line. It is sectional drawing in the axial direction which shows the 2nd form of the stepping motor which concerns on this invention. It is a perspective view which shows the rotor of the stepping motor of FIG. It is sectional drawing in the axial direction which shows the 3rd form of the stepping motor which concerns on this invention. It is a perspective view which shows the rotor of the stepping motor of FIG. It is sectional drawing in the axial direction which shows the 4th form of the stepping motor which concerns on this invention. It is a perspective view which shows the rotor of the stepping motor of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer cylindrical yoke 2 Inner cylindrical yoke 3 Annular plate yoke 4 Drive coil 5 Permanent magnet 6 Inductor 7, 10 Outer cylindrical yoke 7a, 10a Notch 8, 11 Inner cylindrical yoke 9, 12 Annular plate yoke 13, 14 Solenoid windings 15 and 16 Permanent magnets 17 and 18 Inductors 19 and 23 Shaft connecting members 20 and 25 Rotating shaft 21 Yoke coupling members 22 and 24 Inductor 26 Outer cylindrical yoke

Claims (4)

Two large and small cylindrical yokes are concentrically overlapped, one end is magnetically connected, the other end is magnetically opened, a solenoid winding is disposed on the magnetic connection end side, and the magnetic On the open end side, a permanent magnet is annularly arranged so as to be in magnetic contact with the inner circumference of the outer cylindrical yoke, and the permanent magnet is magnetized in a multi-pole direction so as to form the first magnetic circuit. ,
The first magnetic circuit and the second magnetic circuit having the same configuration are arranged in a predetermined gap with the magnetic open end sides facing each other to form an armature, and the first magnetic circuit and the second magnetic circuit Inside each permanent magnet of the magnetic circuit, an inductor having an outer peripheral shape whose radial magnetic resistance changes periodically in the circumferential direction is positioned, and these inductors are supported by a rotating shaft as a rotor,
A stepping motor comprising a magnetic circuit for magnetically coupling the inner cylindrical yoke and the inner diameter or axial side surface of the inductor via a gap.   2. The stepping motor according to claim 1, wherein the inductor of the first magnetic circuit and the inductor of the second magnetic circuit are magnetically integrated.   The stepping motor according to claim 2, wherein the rotating shaft is made of a soft magnetic material, and the magnetically integrated inductor is supported by the rotating shaft.   2. The stepping motor according to claim 1, wherein the outer cylindrical yoke of the first magnetic circuit and the outer cylindrical yoke of the second magnetic circuit are integrally formed of a soft magnetic material.

Images