JP2003009498A - Stepping motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a subminiature stepping motor with high performance at low cost by solving a problem that phase aligning of two pairs of stators is complex and difficult and the cost rises, in regard to a subminiature stepping motor which is utilized for driving the lenze of a camera or for feeding and tilting with optical media equipments. SOLUTION: A coil bobbin 22 has a terminal 22a protruding in its outward direction. The both sides in its rotational direction which are of almost same radius position as a case 31 is taken as stator regulation portions 22f. An outer periphery opening 31 which is capable of engaging with the stator regulation portions 22f is arranged and then engaged. Furthermore, the stator regulation portions 22f of the coil bobbin 22 are so set as to form a prescribed gap angle against the york regulation portions 22d, 22e.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stepping motor, and more particularly, to a microminiature device suitable for driving a lens of a camera or feeding and tilting an optical media device.
The present invention relates to a small diameter claw pole type stepping motor.

[0002]

2. Description of the Related Art Conventionally, as a small-sized and small-diameter stepping motor, one described in JP-A-10-327570 has been known. FIG. 5 shows the structure of the stepping motor. In FIG. 5, the stepping motor is similar to the conventional general claw pole type, and has a rotor provided with a magnet 115 magnetized in multiple poles on the outer periphery, and an outer yoke 111 and an inner yoke 11 provided with pole tooth portions closely opposed to the outer periphery.
2. A stator 114 (two sets) having a coil bobbin 113 around which an exciting coil for exciting the coil is wound is provided. What is different from the conventional one is that the position of the coil bobbin 113 is arranged on both axial ends of the magnet 115. With such a structure, the outer diameter of the motor can be reduced to substantially the same size as the outer diameter of the magnet plus the thickness of the pole teeth, and an ultra-compact and small diameter shape can be realized.

However, the motor having this structure is more difficult to manufacture than the conventional general claw pole type motor. Here, the conventional type means that the pole teeth of the stator and the exciting coil / coil bobbin are arranged on the same plane on the outer peripheral side of the magnet. With such a structure, it was possible to easily form the coil bobbin having a U-shaped cross section at the same time by resin-molding integrally while positioning the phases of the two yokes forming the stator at an electrical angle of 180 degrees. further,
It was also possible to easily form the two stators integrally while positioning the phases at an electrical angle of 90 degrees. A magnetic circuit was completed by winding an exciting coil around this and inserting it into a cylindrical outer case made of a magnetic material, and a motor could be constructed.

The above publication also discloses a resin integrally molded as shown in FIG. However, in the motor of this structure, it was not easy to integrally mold the stator. The exciting coil is connected to the outer yoke 111.
Because it has to be stored inside. In the case of integral molding, in consideration of the connection of the exciting coil to the outside, the coil bobbin 113 has the end of the exciting coil connected to a terminal pin or the like in advance so as to be projected to the outside. Then, the coil bobbin is inserted into the yoke and then integrally molded to embed it. However, when the coil bobbin 113 is embedded and integrally molded as described above, the end of the exciting coil may be broken due to the resin molding pressure.

Another problem is the line processing of the exciting coil.
In the conventional type, since the coil bobbin is arranged on the outermost periphery of the motor, it is easy to add / form a terminal such as a pin there. Further, since the two sets of coil bobbins are close to each other, the terminals can be formed collectively. However, in the motor having the structure disclosed in the above publication, since the coil bobbin 113 is inside the outer yoke 111, it is not easy to provide the wire processing terminal. Moreover, since the coil bobbins 113 are separately arranged on both end sides in the axial direction, it is not easy to form a solid wire processing terminal.

[0006]

As described above, in the conventional motor described above, the outer yoke 111 and the inner yoke 112 of the stator cannot be resin-molded in advance to be integrally formed. It was difficult to position the phase stably. Moreover, the line treatment was also difficult. The present invention solves such a conventional problem, and an object of the present invention is to provide a small-sized and small-diameter stepping motor in which the phases of two stators can be easily and stably regulated and wire processing can be easily performed. .

[0007]

In order to achieve the above object, a stepping motor according to a first aspect of the present invention comprises a rotor having a rotor magnet having a multi-pole magnetized outer periphery, and two sets of rotors closely facing each other. Is a claw pole type stepping motor in which exciting coils of the stator are arranged on both axial ends of a rotor magnet, and the stator includes an inner yoke, a coil bobbin, and an outer yoke that can be fitted to each other. The coil bobbin is made of an insulating material and holds the exciting coil, and the inner yoke is made of a magnetic material.The flat part of the coil bobbin is located on one end surface side of the coil bobbin and extends from the flat plate portion to face the outer peripheral surface of the rotor magnet. The outer yoke is made of a magnetic material and has a tooth portion, and a flat plate portion disposed on the other end surface side of the coil bobbin and an outer yoke of the rotor magnet extending from the flat plate portion. And a pole tooth portion disposed at a position having a phase difference of 180 degrees in electrical angle with respect to the pole tooth portion of the inner yoke. Are provided with mutually engageable stator engaging portions, and the stator engaging portions are engaged with each other to position the rotational position between the two stators.

As described above, the stator comprises the inner yoke, the coil bobbin and the outer yoke which can be fitted to each other. In other words, each has a form that can be independently manufactured and assembled. Therefore, after the exciting coil is wound around the coil bobbin, they can be fitted to each other to form the stator, so that large-scale integral molding equipment is not required.

Further, in this way, the stator bobbin is provided on the end faces of the two coil bobbins so as to be engaged with each other, and the position in the rotational direction between the two stators is positioned. As a result, when the angle between the inner yoke and the outer yoke is regulated by the coil bobbin, the angle between the stators is directly regulated by the coil bobbin. Therefore, the number of members involved in angle regulation is small, and the cumulative error can be reduced, so
The phase of one stator can be regulated easily and stably.

In the stepping motor according to the second aspect of the present invention, a part of the coil bobbin is projected outwardly from the outer diameters of the inner yoke and the outer yoke to form a projecting portion, and the axial end surface of the projecting portion is the projecting portion. Position the poles of the inner and outer yokes at the tip end side of the pole teeth at approximately the same position or slightly project,
It serves as a stator engaging portion.

Thus, the stator engaging portion is provided at substantially the same position as the axial end surfaces of the inner and outer yokes on the tip side of the pole teeth. According to this, when the pole teeth portions of the two sets of stators are closely opposed to each other, the stator engaging portions are simultaneously engaged. Therefore, the two sets of stators have the same shape,
Since it is easy to manufacture using the same member, an inexpensive stepping motor can be provided.

As described above, the stator engaging portion is provided outside the outer diameters of the inner and outer yokes. Therefore, the angle error due to the dimensional error of the stator engaging portion can be reduced, so that the phases of the two stators can be regulated more stably.

In a stepping motor according to a third aspect of the present invention, a part of the coil bobbin is projected outward from the outer diameters of the inner yoke and the outer yoke to form a terminal portion, and the terminal pin made of metal is attached to the terminal portion. And the end of the exciting coil is connected.

Thus, the terminal portion is provided at a position outside the outer diameters of the inner and outer yokes of the coil bobbin. Therefore, it is possible to provide a small stepping motor having a small diameter, which facilitates terminal wire processing and external connection of the exciting coil and facilitates wire processing.

A stepping motor according to a fourth aspect of the present invention is provided with a rotor having a rotor magnet having a multi-pole magnetized outer periphery and two sets of stators closely facing each other, and an exciting coil of the stator is used as the rotor. It is a claw pole type stepping motor arranged on both axial ends of a magnet, and a stator is configured with an inner yoke, a coil bobbin, and an outer yoke that can be fitted to each other. The coil is wound and held, and the inner yoke is made of a magnetic material, and has a flat plate portion arranged on one end surface side of the coil bobbin and a pole tooth portion that extends from the flat plate portion and faces the outer peripheral surface of the rotor magnet. , The flat plate portion arranged on the other end surface side of the coil bobbin and the electrical flat portion extending from the flat plate portion and facing the outer peripheral surface of the rotor magnet and the pole tooth portion of the inner yoke A pole tooth portion arranged at a position having a phase difference of 180 degrees, and a case for surrounding and holding the outer circumferences of these members, and a stator regulating portion is provided on the coil bobbin at substantially the same radial position as the case, The case is provided with an outer peripheral surface opening that can be fitted with the stator restricting portion, and the stator restricting portion and the outer peripheral surface opening are engaged with each other to position the rotational position between the two stators.

In this way, the coil bobbin is provided with the stator regulating portion at a position substantially the same in radius as the case, and is fitted with the outer peripheral surface opening provided in the case to position the rotational position between the two stators. According to this, the case performs centering of two sets of stators with its inner diameter, and at the same time,
The centering of the two yokes that make up the stator is also performed. In addition, the rotational position of the stator will be restricted. That is, since these position restrictions are performed at the same time, the phase between the stators of the motor can be kept extremely good. Therefore, it is possible to provide a small-sized small-diameter stepping motor in which the phases of the two stators are regulated more stably.

In the stepping motor according to a fifth aspect of the present invention, the outer peripheral surface opening of the case has a substantially rectangular shape, and the stator restricting portions of the two coil bobbins have substantially the same shape. The stator regulating portions of the two coil bobbins are fitted to each other to position the rotational position between the two stators.

As described above, the stator restricting portions of the two coil bobbins are fitted into the outer peripheral surface opening of the case to position the rotational position between the two stators. According to this, the outer peripheral surface opening of the case can be made into a simple shape, so that the shape error can be reduced and the phases of the two stators can be regulated more stably.

As described above, the stator restricting portions of the two coil bobbins have substantially the same shape. In particular, when two coil bobbins are manufactured with the same mold, the shape error of the two coil bobbins is small, so that the fitting error of the stator restriction portion with respect to the outer peripheral surface opening can be easily reduced. Therefore 2
The phase of one stator can be regulated more stably.

A stepping motor according to a sixth aspect of the present invention is provided with a rotor having a rotor magnet having a multi-pole magnetized outer periphery and two sets of stators closely facing each other, and the exciting coil of the stator is used as the rotor. This is a claw pole type stepping motor arranged on both axial ends of the magnet, and the stator is configured with an inner yoke, a coil bobbin and an outer yoke that can be fitted to each other. The coil is wound and held, and the inner yoke is made of a magnetic material, and has a flat plate portion arranged on one end surface side of the coil bobbin and a pole tooth portion that extends from the flat plate portion and faces the outer peripheral surface of the rotor magnet. , The flat plate portion arranged on the other end surface side of the coil bobbin and the electrical flat portion extending from the flat plate portion and facing the outer peripheral surface of the rotor magnet and the pole tooth portion of the inner yoke There is a pole tooth portion arranged at a position having a phase difference of 180 degrees, and further, there is a spacer separating the two stators in a position in which they closely oppose each other, and a contact surface between the spacer and the stator. Are provided with spacer engaging portions that engage with each other, and the spacer engaging portions are engaged with each other to position the rotational direction between the two stators.

As described above, spacer engaging portions for restricting the angle of the stator with respect to the spacers are provided at positions where the two sets of stators closely face each other. According to this
By replacing the spacer, the stator can be positioned with an arbitrary phase difference. Therefore, a motor having desired characteristics can be easily manufactured. Further, in this way, the spacer engaging portion is engaged with the end surface of the stator to position the rotational position between the two stators. Since they are engaged on the surface, the engagement is easy, and the phases of the two stators can be easily and stably regulated.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an exploded perspective view of a motor constituent member of the present embodiment, FIG. 2A is a plan view showing an appearance of a terminal portion of the motor of the present embodiment, and FIG. 2B is a sectional view showing the structure of the motor. , Fig. 3
FIG. 3A is a sectional view including the axis of the coil bobbin of the motor of the present embodiment, and FIG. 3B is a plan view in the coaxial line direction.

The motor according to the present embodiment has a sufficient torque while being extremely small, for example, having an outer diameter of less than 6 mm. That is, as mentioned earlier, the exciting coils are arranged at both axial ends of the rotor magnet,
This is because the outer diameter was reduced while maintaining the generated torque.

In FIGS. 1 and 2B, the rotor 10 of this motor is composed of a rotor magnet 11 and a shaft 12 whose outer circumference is multi-pole magnetized. Rotor 10
Has resin washers 13 on both sides, and a slight clearance is provided between the washers 13 and the opposing surface.

The stators 20 facing the rotor each have two sets of the same shape, and are arranged opposite to each other on both axial sides of the rotor magnet 11. The stator 20 includes an inner yoke 21, a coil bobbin 22, and an outer yoke 23, which are assembled by fitting them in the axial direction. Further, the stator 20 includes a cylindrical boss 24 located on the inner diameter side of the coil bobbin 22 and magnetically and mechanically connecting the inner diameter side of the inner yoke 21 and the inner diameter side of the outer yoke 23.

Here, the coil bobbin 22 is made of an insulating material such as resin and is a member whose main function is to hold the exciting coil 25 in a wound manner. A terminal portion 22a is provided on the outer peripheral side of one of the terminals, and the terminal pin 26 is embedded therein, and the terminal of the exciting coil 25 is connected and held.

The inner yoke 21 is made of a magnetic material, and one end surface 22b of the coil bobbin 22 facing the rotor magnet 11 is formed.
It has a flat plate portion 21a arranged on the side and a pole tooth portion 21b extending from the flat plate portion 21a and facing the outer peripheral surface of the rotor magnet 11.

The outer yoke 23 is also made of a magnetic material, and has a flat plate portion 23a arranged on the other end surface side of the coil bobbin 22 and a pole tooth portion 23b extending from the flat plate portion 23a and facing the outer peripheral surface of the rotor magnet 11. The pole tooth portion 23b is arranged at a position having a phase difference of 180 degrees in electrical angle with respect to the pole tooth portion 21b of the inner yoke.

FIG. 3 shows the detailed shape of the coil bobbin.
The inner yoke 21 is provided on one end surface 22b side of the coil bobbin 22.
The flat plate portion 21a of the outer yoke 23 faces and abuts on the other end surface 22c of the outer yoke 23. On the other hand, on the outer peripheral side of the coil bobbin 22, yoke restricting portions 22d and 22e are provided at substantially the same radial position as the pole tooth portion. Of these, the yoke restricting portion 22d is engaged so as to sandwich both side surfaces in the rotation direction of the pole tooth portion 21b of the inner yoke 21, and the yoke restricting portion 22e is
The two adjacent pole tooth portions 23b of the inner yoke 23 are engaged with each other so as to be sandwiched between both side surfaces in the rotation direction. In this way, the inner yoke and the coil bobbin and the coil bobbin and the outer yoke are engaged with each other and positioned, and the inner yoke and the outer yoke are correctly held at a position of an electrical angle of 180 °.

In the present embodiment, the yoke restricting portion 22
Although an example in which only one set of d and 22e is formed is shown, it is also possible to provide more accurate positioning by providing a large number of yoke restricting portions in the circumferential direction.

The member that covers the outside of the stator is the case 31. The case 31 is made of a non-magnetic material and holds the two sets of stators 20 concentrically. A bracket 32 is fixed to the axially open end of the case 31 to hold the two sets of stators 20 in the axial direction. A bearing 33 is attached to the center of the case 31 and the bracket 32, and rotatably supports the shaft 12 of the rotor 10.

At this time, a spacer 34 made of a non-magnetic material is sandwiched between the surfaces of the two stators 20 that are closely opposed to each other.
The mutual positions are kept to prevent unnecessary magnetic loops from occurring in the pole teeth. Here, the spacer 34 is provided with a protrusion 34a, which separates the two terminal portions 22a from each other.
You may make it further protrude from 2a. Then, the mating board soldered to the terminal pins 26 can be prevented from coming too close to the surface of the terminal portion 22a, and the disconnection due to the pressure of the terminals can be prevented.

Here, the case 31 also serves to position the rotational position between the two sets of stators. This is done as follows. First, coil bobbin 2
2 has a terminal portion 22a projecting in the outer peripheral direction, and the stator regulating portion 22f has a radial position substantially the same as that of the case 31 on both side faces in the rotation direction. On the other hand, case 31
The outer peripheral surface opening 3 that can be fitted to the stator regulation portion 22f
1a is provided and these are fitted together. And further,
The stator restricting portion 22f of the coil bobbin 22 is set such that its position forms a predetermined deviation angle with respect to the yoke restricting portions 22d and 22e. For example, when it is desired to maintain the electrical phase difference between both stators at 90 °, the electrical phase difference between the stator restricting portion 22f and the yoke restricting portions 22d and 22e is set to 45 °, and two sets of the stators 20 are opposed to each other. 90 ° by overlapping the parts 22f at the same position
Creates the phase difference of. In this embodiment, the outer peripheral surface opening 3
The purpose is achieved by making 1a into a substantially rectangular shape and arranging two sets of the stator restricting portions 22f side by side so that they fit properly.

A mechanism for positioning the rotational position between the two sets of stators is also provided on the close opposing surfaces of the two coil bobbins 22. That is the stator engaging portion 22g. As a result, the two stators 20 are attached to the case 31.
Positioning can be performed in advance before inserting into the stator, and the stator restricting portion 22f and the outer peripheral surface opening 31 of the case
The fitting with a can be done smoothly.

In the motor thus assembled, a printed circuit board (not shown) is connected to the terminal pin 26 of the terminal portion, and two sets of exciting coils 25 are energized and driven to rotate.

As described above, in this embodiment, the stator 20 comprises the inner yoke 21, the coil bobbin 22, and the outer yoke 23 which can be fitted to each other. In other words, each has a form that can be independently manufactured and assembled. Therefore, the exciting coil 25 can be wound around the coil bobbin 22 and then fitted together to form the stator 20, so that a large-scale integral molding facility is not required.

As described above, in this embodiment, 2
A pair of coil bobbins 22 are provided at their end surfaces with stator engaging portions 22g that can be engaged with each other, and the position in the rotational direction between the two stators is positioned. As a result, the inner yoke 21
When the coil bobbin 22 regulates the angle between the outer yokes 23, the coil bobbin 22 directly fixes the stator 20.
The angle will be regulated. Therefore, the number of members involved in angle regulation is small, and the cumulative error can be reduced, so
The phase of one stator can be regulated easily and stably.

As described above, in this embodiment, the stator engaging portion 22g is provided at substantially the same position as the axial end surfaces of the inner yoke 21 and the outer yoke 23 on the tip side of the pole teeth 21b and 23b. According to this, when the pole tooth portions of the two sets of stators 20 are closely opposed to each other, the stator engaging portions 22g
Will be engaged. Therefore, two sets of stators 20
Since they have the same shape and can be easily manufactured by using the same member, an inexpensive stepping motor can be provided.

As described above, in this embodiment, the stator engaging portion 22g is provided outside the outer diameter of the inner yoke 21 and the outer yoke 23. Therefore, the angular error due to the dimensional error of the stator engaging portion 22g can be reduced, and the phases of the two stators can be regulated more stably.

As described above, in this embodiment, the terminal portion 22a is provided at a position outside the outer diameters of the inner and outer yokes of the coil bobbin 22. Therefore, the terminal wire of the exciting coil 25 can be easily processed and externally connected, and it is possible to provide a small-sized and small-diameter stepping motor in which the wire processing is easy.

As described above, in the present embodiment, the coil bobbin 22 is provided with the stator restricting portion 22f at substantially the same radial position as the case 31, and the stator bobbin 22 is fitted into the outer peripheral surface opening 31a provided in the case 31 to form two stators. The position in the rotation direction between them is positioned. According to this, the case 31 performs centering of the two sets of the stator 20 with its inner diameter, and at the same time, the two yokes 21 and 23 forming the stator 20.
The centering of is also performed. In addition, the rotational position of the stator 20 will be restricted. That is, since these position restrictions are performed at the same time, the phase between the stators of the motor can be kept extremely good. Therefore, it is possible to provide a small-sized small-diameter stepping motor in which the phases of the two stators 20 are regulated more stably.

As described above, in this embodiment, the two coil bobbins 2 are provided in the outer peripheral surface opening 31a of the case 31.
The two stator restricting portions 22f are fitted to position the rotational direction position between the two stators 20. According to this, the outer peripheral surface opening 31a of the case 31 can be made into a simple shape, and therefore the shape error can be reduced,
The phases of the two stators 20 can be regulated more stably.

As described above, in this embodiment, 2
The stator restricting portions 22f of the two coil bobbins have the same shape. Then, the two coil bobbins 22 can be manufactured with the same mold. Therefore, since the shape error of the two coil bobbins is small, the fitting error of the stator restricting portion 22f with respect to the outer peripheral surface opening 31a can be easily reduced, and the phases of the two stators can be restricted more stably.

(Second Embodiment) Another embodiment will be described with reference to FIG. FIG. 4 shows the spacer of the motor. The spacer 44 separates the two sets by sandwiching the two sets of stators (not shown) on the surfaces that closely face each other.

In the figure, the spacer 44 has a shape similar to that of the spacer 34, except that a spacer engaging portion 44b for engaging with each other on both contact surfaces of the two sets of stators is newly provided. On the other hand, the stator (not shown) has
A concave portion that engages with the convex spacer engaging portion 44b is provided. Then, these are engaged with each other to position the two stators in the rotational direction.

As described above, in this embodiment, the spacers 44 are provided at the positions where the two sets of stators closely face each other.
Spacer engaging portion 44 for regulating the angle of the stator with respect to
b is provided. According to this, the stator can be positioned with an arbitrary phase difference by exchanging the spacer 44. Therefore, a motor having desired characteristics can be easily manufactured. Further, in this way, the spacer engaging portion 44b is engaged with the end surface of the stator to position the rotational direction position between the two stators. Since they are engaged on the surface, the engagement is easy, and the phases of the two stators can be easily and stably regulated.

In the above description, an example in which the shaft is composed of a straight shaft and a normal bearing has been described.
Other configurations in which the shaft is a lead screw and the bearing is a pivot bearing can be similarly implemented.

[0048]

As described above, according to the present invention, it is possible to provide a small-sized and small-diameter stepping motor in which the phases of the two stators can be easily and stably regulated and the line processing can be easily performed.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a motor constituent member according to a first embodiment.

FIG. 2A is a plan view showing the appearance of a terminal portion of the motor of the first embodiment, and FIG. 2B is a sectional view showing the structure of the motor.

3A is a cross-sectional view including the axis of the coil bobbin of the motor according to the first embodiment, and FIG. 3B is a plan view in the coaxial line direction.

FIG. 4 is a perspective view of a spacer in the motor according to the second embodiment.

FIG. 5 is a perspective view showing the structure of a conventional motor.

FIG. 6 is a perspective view showing the structure of another conventional motor.

[Explanation of symbols]

10 rotor 11 rotor magnet 12 shafts 13 washers 20 stator 21 Inner yoke 21a, 23a Flat plate part 21b, 23b pole teeth 22 coil bobbin 22a Terminal part (projection part) 22b One end surface 22c The other end surface 22d, 22e Yoke regulation part 22f Stator regulation part 22g Stator engagement part 23 Outer yoke 24 Boss 25 Excitation coil 26 terminal pins 31 cases 31a Outer peripheral surface opening 32 bracket 33 bearings 34,44 spacer 34a protrusion 44b Spacer engaging part

Claims (6)

[Claims] 1. A rotor having a rotor magnet having a multi-pole magnetized outer periphery and two sets of stators closely facing each other, and exciting coils of the stator are arranged on both axial ends of the rotor magnet. A claw pole type stepping motor, wherein the stator includes an inner yoke, a coil bobbin, and an outer yoke that can be fitted to each other, the coil bobbin is made of an insulating material, and holds the exciting coil in a wound state. The inner yoke is made of a magnetic material, and has a flat plate portion arranged on one end surface side of the coil bobbin and a pole tooth portion that extends from the flat plate portion and faces the outer peripheral surface of the rotor magnet, and the outer yoke is made of a magnetic material. A flat plate portion arranged on the other end surface side of the coil bobbin and an extending from the flat plate portion, facing the outer peripheral surface of the rotor magnet, and an electrical angle with respect to the pole tooth portion of the inner yoke. A pole tooth portion disposed at a position having a phase difference of 180 degrees, and a stator engaging portion that is engageable with each other is provided on an end surface of the two sets of the stators on the side where the coil bobbins closely face each other, A stepping motor in which the stator engaging portions are engaged to position the rotational direction between the two stators. 2. A part of the coil bobbin is projected outward from the outer diameter of the inner yoke / outer yoke to form a projecting portion, and the axial end surface of the projecting portion is located at the pole tooth portion of the inner yoke / outer yoke. The stepping motor according to claim 1, wherein the stator engaging portion is formed by projecting it at substantially the same position as or slightly protruding from the axial end surface on the tip side. 3. A part of the coil bobbin is projected outward from the outer diameters of the inner yoke and the outer yoke to form a terminal portion, and a terminal pin made of metal is projected on the terminal portion to connect the end of the exciting coil. The stepping motor according to claim 1, further comprising: 4. A rotor having a rotor magnet having a multi-pole magnetized outer periphery and two sets of stators closely facing each other, and exciting coils of the stator are arranged on both axial ends of the rotor magnet. A claw pole type stepping motor, wherein the stator includes an inner yoke, a coil bobbin, and an outer yoke that can be fitted to each other, the coil bobbin is made of an insulating material, and holds the exciting coil in a wound state. The inner yoke is made of a magnetic material, and has a flat plate portion arranged on one end surface side of the coil bobbin and a pole tooth portion that extends from the flat plate portion and faces the outer peripheral surface of the rotor magnet, and the outer yoke is made of a magnetic material. A flat plate portion arranged on the other end surface side of the coil bobbin and an extending from the flat plate portion, facing the outer peripheral surface of the rotor magnet, and an electrical angle with respect to the pole tooth portion of the inner yoke. A pole tooth portion arranged at a position having a phase difference of 180 degrees, and a case for surrounding and holding the outer periphery of these members, and a stator regulating portion is provided on the coil bobbin at substantially the same radial position as the case. An outer peripheral surface opening is provided in the case so that the stator restricting portion can be fitted to the case, and the stator restricting portion and the outer peripheral surface opening are fitted to each other to position a rotational direction position between the two stators. Become a stepping motor. 5. The outer peripheral surface opening of the case has a substantially rectangular shape, the stator restricting portions of the two coil bobbins have substantially the same shape, and the stator restricting portions of the two coil bobbins are fitted into the outer peripheral surface openings. The stepping motor according to claim 4, wherein the two stators are combined to position a position in the rotational direction between the two stators. 6. A rotor having a rotor magnet having a multi-pole magnetized outer periphery, and two sets of stators closely opposed to the rotor magnet, and exciting coils of the stator are arranged on both axial ends of the rotor magnet. A claw pole type stepping motor, wherein the stator includes an inner yoke, a coil bobbin, and an outer yoke that can be fitted to each other, the coil bobbin is made of an insulating material, and holds the exciting coil in a wound state. The inner yoke is made of a magnetic material, and has a flat plate portion arranged on one end surface side of the coil bobbin and a pole tooth portion that extends from the flat plate portion and faces the outer peripheral surface of the rotor magnet, and the outer yoke is made of a magnetic material. A flat plate portion arranged on the other end surface side of the coil bobbin and an extending from the flat plate portion, facing the outer peripheral surface of the rotor magnet, and an electrical angle with respect to the pole tooth portion of the inner yoke. There is a pole tooth portion arranged at a position having a phase difference of 180 degrees, and there is a spacer separating the two stators from each other at a position where the two stators closely face each other. A stepping motor, wherein spacer contact portions that engage with each other are provided on the contact surfaces, and the spacer engagement portions are engaged with each other to position the rotational position between the two stators.