JP2004072917A - Hybrid type stepping motor, method of assembling the same, and optical device - Google Patents

Abstract

The present invention provides a hybrid stepping motor that can be easily miniaturized and multi-stepped and can be easily manufactured.
In an inner rotor type hybrid stepping motor, a stator core is divided into a plurality of, for example, four divided stator cores, and each of the divided stator cores includes a pair of bearing housings. It is configured to be sandwiched between. By dividing the stator core 20, even when the diameter is reduced, the winding of the coil 25 around each stator magnetic pole 23 is facilitated. The hybrid type stepping motor can be multi-stepped by increasing the number of stator pole teeth of the stator magnetic pole 23 and the number of rotor pole teeth 19 of the rotor cores 17 and 18.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an inner rotor type hybrid stepping motor, an assembling method thereof, and an optical device having optical members such as a laser light source and a lens.
[0002]
[Problems to be solved by the invention]
The hybrid configuration of the inner rotor type hybrid stepping motor is as follows. That is, a plurality of stator magnetic poles having a plurality of stator pole teeth at the tip are provided on an inner peripheral portion of a cylindrical stator core, and a coil is wound around each of the stator magnetic poles. The stator is constituted by the stator core and the coil. A rotor that rotates integrally with the rotation shaft is provided inside the stator. The rotor has a ring-shaped permanent magnet fixed to the outer periphery of the rotating shaft and magnetized in the axial direction, and a pair of permanent magnets fixed to both end surfaces in the axial direction of the permanent magnet and having a plurality of rotor pole teeth on the outer periphery. And the rotor core. The outer peripheral surface of the rotor pole tooth is radially opposed to the tip end surface of the stator pole tooth via a gap.
[0003]
It is desired to reduce the size of the motor having such a configuration. In order to reduce the size of the motor having such a configuration, it is necessary to reduce the diameter of the stator core.However, when the diameter of the stator core is reduced, the diameter of the coil with respect to the stator magnetic poles existing in the inner peripheral portion of the stator core is reduced. There is a problem that winding becomes difficult.
[0004]
On the other hand, Japanese Patent Application Laid-Open No. 2001-103690 discloses the following technology in a stator of an inner rotor type stepping motor. That is, as shown in FIGS. 8 and 9, the cylindrical stator core 1 is divided into a plurality of divided stator cores 2, and a pin 3 is provided at one end of each of the divided stator cores 2. A hole 4 is provided at an end, and adjacent divided stator cores 2 are connected in a line by fitting the pin 3 and the hole 4. After the coil 5 is wound around the magnetic pole 2a of each split stator core 2, the plurality of split stator cores 2 are combined in an annular shape.
[0005]
In the above publication, the stator core 1 is divided into a plurality of divided stator cores 2, so that the winding of the coil 5 around each magnetic pole 2a is facilitated. However, in the above configuration, if the clearance between the pin portion 3 and the hole portion 4 is too large, rattling increases, and the magnetic pole 2a of the split stator core 2 and the rotor magnetic pole of a rotor (not shown) are formed. If the clearance is too small, the clearance may be too small. If the clearance is too small, the assembling may be difficult, and the clearance may be difficult to manage. Further, when reducing the diameter of the stator core 1 to reduce the size of the motor, it is difficult to secure a space for forming the pin portion 3 and the hole portion 4, and it is difficult to reduce the size in this configuration.
[0006]
In the case of a stepping motor having a small outer diameter of, for example, 10 mm or less, a two-phase claw pole type as shown in FIG. 10 is generally used. Since the stator 6 has a configuration in which the stator 6 wraps the comb-shaped soft iron magnetic path 7 with the coil 8, it is relatively easy to reduce the diameter of the stator 6.
[0007]
However, this claw-pole type requires a large number of magnetizations on the outer peripheral surface of the ring-shaped permanent magnet 10 in the rotor 9, and the number of steps is determined by the number of poles and the number of claw poles 7a. The number of steps is small. Increasing the number of steps requires more magnetization on the outer peripheral surface of the permanent magnet 10. However, if the magnetization pitch is reduced, the magnetic force cannot be increased, and the torque will be reduced. Difficult to step.
[0008]
The present invention has been made in view of the above circumstances, and a first object is to provide a hybrid type stepping motor that can be easily miniaturized and multi-stepped and can be easily manufactured. It is an object of the present invention to provide a method of manufacturing a hybrid type stepping motor capable of manufacturing such a motor more easily. Further, a third object is to provide an optical device capable of positioning optical members such as a laser light source and a lens with a simple configuration and with high accuracy.
[0009]
[Means for Solving the Problems]
In order to achieve the first object described above, a hybrid stepping motor according to the first aspect of the present invention provides
A pair of bearing housings arranged to face each other in the axial direction,
A rotating shaft rotatably supported via a bearing on the pair of bearing housings, a ring-shaped permanent magnet fixed to the outer peripheral portion of the rotating shaft and magnetized in the axial direction,
A pair of rotor cores fixed to both end surfaces in the axial direction of the permanent magnet and each having a plurality of rotor pole teeth on the outer periphery thereof, and integrally rotating with the rotation shaft;
A yoke portion which is divided into a plurality in the circumferential direction and is arranged so as to have a cylindrical shape surrounding the pair of rotor cores, and is sandwiched between the pair of bearing housings, and an inner peripheral portion of the yoke portion. Provided, a plurality of split stator cores provided with a stator magnetic pole having a plurality of stator pole teeth opposed to each other from the radial direction via the rotor pole teeth and a gap at the tip,
And a plurality of coils respectively mounted on the stator magnetic poles.
[0010]
In the configuration described above, the stator core is divided into a plurality of divided stator cores. Therefore, even if the diameter of the stator core is reduced, it is possible to easily wind the coil around each stator magnetic pole. Further, since the plurality of split stator cores are configured to be sandwiched between a pair of bearing housings, it is necessary to provide a configuration in which adjacent split stator cores are connected by fitting a pin portion and a hole portion. do not do. Also, in the hybrid type stepping motor, the number of steps is determined by the number of stator pole teeth and the number of rotor pole teeth, and since these pole teeth are convex portions, they differ from the claw pole type. , The pitch can be made finer, and the number of steps can be easily increased.
[0011]
According to a second aspect of the present invention, in the first aspect of the present invention, each of the split stator cores is formed of an integral structure of a high magnetic permeability soft magnetic material. According to this, the split stator core can be easily manufactured as compared with the case where a large number of steel plates are stacked, and it is easy to cope with downsizing.
[0012]
According to a third aspect of the present invention, in the first or second aspect of the present invention, each of the split stator cores is formed by sintering. According to this, the split stator core can be manufactured more easily.
[0013]
According to a fourth aspect of the present invention, when assembling the hybrid stepping motor according to any one of the first to third aspects,
A permanent magnet magnetized in the axial direction, and disposed on both end surfaces in the axial direction of the permanent magnet, and an outer peripheral surface is provided on an outer peripheral portion along a tip end surface of a stator pole tooth in the split stator core, and has a circumferential width. A positioning jig provided with a pair of positioning members made of a magnetic material having a plurality of protrusions formed so as to have substantially the same width as the width of the tip of the stator magnetic pole,
A plurality of the divided stator cores are arranged and positioned around the positioning jig by attracting a tip end surface of the stator pole teeth to an outer peripheral surface of each of the projections of the positioning jig, and thereafter, The plurality of split stator cores are sandwiched between the pair of bearing housings.
According to the above-described means, the plurality of split stator cores are positioned using the magnetic attraction force of the positioning jig, so that assembly can be facilitated.
[0014]
According to a fifth aspect of the present invention, there is provided an optical device having an optical member such as a laser light source or a lens, wherein the hybrid type stepping motor according to any one of the first to third aspects is used as a driving unit of the optical member. And According to this, by using a small-sized multi-stepping stepping motor as a driving means of the optical member, precise positioning can be performed without using a speed reducer such as a worm gear.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
First, FIGS. 1 and 2 show a longitudinal front view and a longitudinal side view of a two-phase hybrid type stepping motor. In FIG. 1, a rotating shaft 12 of a rotor 11 is rotatably supported by a pair of bearing housings 13 and 14 arranged to face each other in the axial direction via a bearing 15 composed of a ball bearing. One end protrudes outward from one bearing housing 13.
[0016]
A ring-shaped permanent magnet 16 is fixed to an outer peripheral portion of the rotating shaft 12, and a pair of left and right rotor cores 17 and 18 are fixed to both end surfaces in the axial direction of the permanent magnet 16. Of these, the permanent magnet 16 is magnetized in the axial direction, and one end face has an N pole and the other end face has an S pole. As shown also in FIG. 4, a large number of rotor pole teeth 19, each consisting of a ridge extending in the axial direction, are formed on the outer periphery of the rotor cores 17, 18, in this case, fifteen in each case. In this case, the rotor pole teeth 19 of one rotor core 17 and the rotor pole teeth 19 of the other rotor core 18 are shifted by 12 degrees in this case so as to be staggered in the circumferential direction.
[0017]
A cylindrical stator core 20 is arranged between the pair of bearing housings 13 and 14 so as to surround the rotor 11. As shown in FIG. 2, the stator core 20 has a configuration in which the stator core 20 is divided into four divided stator cores 21 in the circumferential direction. As shown in FIG. 3, each split stator core 21 integrally includes a yoke portion 22 having an arcuate cross section and a stator magnetic pole 23 protruding from an inner peripheral portion of the yoke portion 22. It has become.
[0018]
Three stator pole teeth 24 each formed of a ridge extending in the axial direction are formed at the tip of each of the stator magnetic poles 23, and the tip surfaces of the stator pole teeth 24 correspond to the rotor. It faces the outer peripheral surface of the pole tooth 19 from the radial direction via a gap. A coil 25 is wound around the outer periphery of each stator magnetic pole 23 after performing an insulation process.
[0019]
Here, the four split stator cores 21 are sandwiched between a pair of bearing housings 13 and 14 in a state of being arranged in a cylindrical shape, and are fixed by bonding or the like. In this case, convex portions 26 are projected from both end surfaces in the axial direction of each split stator core 21, and these convex portions 26 are fitted into concave portions 27 formed in the bearing housings 13 and 14. , In the circumferential direction. A stator 28 is constituted by four split stator cores 21 (stator cores 20) and four coils 25.
[0020]
Each of the split stator cores 21 and the pair of rotor cores 13 and 14 are integrally formed by sintering a soft magnetic material having a high magnetic permeability such as permalloy, permendur, or 3% silicon iron. I have. In addition, you may form by MIM (Metal Injection Molding) (metal injection molding) instead of sinter molding.
[0021]
The beginning and end of winding of the coil 25 are connected to a printed wiring board 29 provided inside the stator core 20 by soldering, and the lead wire 30 soldered to the printed wiring board 29 is connected to the bearing housing 14. From the outside.
[0022]
Next, an assembling method when assembling the motor having the above configuration will be described. When assembling the stator 28, a positioning jig 31 shown in FIG. 6 is used. The positioning jig 31 includes a ring-shaped permanent magnet 32 magnetized in the axial direction, and a pair of positioning members 33 and 34 made of a magnetic material fixed to both end surfaces of the permanent magnet 32 in the axial direction. ing. One end face of the permanent magnet 32 has an N pole, and the other end face has an S pole. Four projections 35 are provided on the outer peripheral portions of the positioning members 33 and 34, respectively.
[0023]
As shown in FIG. 5, the outer peripheral surface 35 a of each convex portion 35 has an arc-shaped cross section along the distal end surface 24 a of the stator pole teeth 24 of the stator magnetic pole 23, and the circumferential width of each convex portion 35. The dimension is set so as to be the same as the width dimension of the tip of the corresponding one stator magnetic pole 23. The radius of the arc of the outer peripheral surface 35a of each convex portion 35 is set to be the same as the radius of the arc of the distal end surface 24a of the stator pole teeth 24.
[0024]
When assembling the stator 28, the coil 25 is wound around the stator magnetic poles 23 of each of the divided stators 21 in advance. Then, as shown in FIGS. 5 and 7, the stator poles of the stator magnetic poles 23 of the divided stator 21 corresponding to the outer peripheral surfaces 35 a of the respective convex portions 35 of the pair of positioning members 33 and 34 in the positioning jig 31. The four divided stator cores 21 are arranged in a cylindrical shape around the positioning jig 31 by attracting the tip surfaces 24 a of the teeth 24 by magnetic attraction. At this time, the width of each stator pole 23 in the circumferential direction is made to match the width of the tip end of the corresponding projection 35. Thus, the four split stator cores 21 are held in a state where they are positioned around the positioning jig 31. In this state, the divided stator cores 21 are fixed to each other by bonding or the like.
[0025]
Thereafter, the positioning jig 31 is removed from the stator core 20, and the rotor 11 is inserted and arranged in the stator core 20 instead, and the bearing housings 13, 14 are arranged on both axial sides of the stator core 20. Then, with the projection 26 of each split stator core 21 and the recess 27 of the bearing housings 13 and 14 fitted together, each split stator core 21 is fixed to the two bearing housings 13 and 14 by bonding or the like. As a result, each split stator core 21 is sandwiched between the pair of bearing housings 13 and 14.
[0026]
According to the above-described embodiment, the following effects can be obtained.
Since the stator core 20 is divided into a plurality of divided stator cores 21, even if the diameter of the stator core 20 is reduced, the coil 25 can be easily wound around each of the stator magnetic poles 23. Further, since the plurality of split stator cores 21 are configured to be sandwiched between the pair of bearing housings 13 and 14, the adjacent split stator cores are connected by fitting the pin portion and the hole portion. Requires no configuration.
[0027]
In the hybrid type stepping motor, the number of steps is determined by the number of stator pole teeth 24 and the number of rotor pole teeth 19, and since the pole teeth 24 and 19 are convex portions, Unlike the pole type, the pitch can be made finer and it is easy to make multiple steps. Incidentally, the step angle θs of the stepping motor is 360 ° / (number of rotor pole teeth × number of phases × 2). In the present embodiment, since the number of rotor pole teeth is 15 and the number of phases is 2, the step angle θs = 6 °, and therefore the number of steps in one rotation of the rotor 11 is 60.
[0028]
Since the split stator core 21 is formed into an integral structure by sintering a high-permeability soft magnetic material, it can be easily manufactured as compared with a case where a large number of steel sheets are laminated. Also, it is easy to cope with miniaturization.
[0029]
Further, when assembling the stator 28, the plurality of split stator cores 21 are positioned by utilizing the magnetic attraction force of the positioning jig 31, so that the assembly can be facilitated.
[0030]
On the other hand, the small-sized and multi-stepping stepping motor of the present embodiment can be used as a driving unit of an optical member such as a laser light source and a lens. According to this, there is an advantage that precise positioning can be performed without using a speed reducer such as a worm gear.
[0031]
The present invention is not limited to the above-described embodiment, but can be modified or expanded as follows.
In the above-described embodiment, a two-phase hybrid type stepping motor has been exemplified. However, the present invention is not limited to this, and the present invention can be applied to a multi-phase hybrid type stepping motor such as three-phase, four-phase, and five-phase. .
Although the rotor pole teeth 19 of the rotor cores 17 and 18 have been described as 15 teeth, the number of teeth is not limited to this, and the number of teeth can be set according to the size of the rotor 11.
[0032]
【The invention's effect】
According to the first aspect of the present invention, it is possible to provide a hybrid type stepping motor that can be easily miniaturized and multi-stepped and can be easily manufactured.
According to the fourth aspect of the present invention, the plurality of split stator cores are positioned by utilizing the magnetic attraction force of the positioning jig, so that assembly can be facilitated.
According to the fifth aspect of the invention, by using a small-sized and multi-stepping stepping motor as the driving means of the optical member, precise positioning can be performed without using a speed reducer such as a worm gear.
[Brief description of the drawings]
1 is a longitudinal sectional front view of a hybrid type stepping motor showing one embodiment of the present invention; FIG. 2 is a longitudinal sectional side view; FIG. 3 is a perspective view of a split stator core; FIG. 4 is a perspective view of a rotor; FIG. 6 is a side view showing a state in which four divided stator cores are arranged around the positioning jig. FIG. 6 is a perspective view of the positioning jig. FIG. 7 is a diagram showing one divided stator core around the positioning jig. FIG. 8 is a plan view of a stator in a conventional inner rotor type motor. FIG. 9 is a perspective view of one split stator core. FIG. 10 is a conventional two-phase claw pole type stepping motor. [Explanation of reference numerals]
In the drawings, 11 is a rotor, 12 is a rotating shaft, 13 and 14 are bearing housings, 15 is a bearing, 16 is a permanent magnet, 17 and 18 are rotor cores, 19 is rotor pole teeth, 20 is a stator core, 21 is a split stator core, 22 is a yoke, 23 is a stator magnetic pole, 24 is a stator pole tooth, 24a is a tip surface, 25 is a coil, 28 is a stator, 31 is a positioning jig, 32 is a permanent magnet, 33 and 34 are positioning members, 35 is a convex part, and 35a is an outer peripheral surface.

Claims (5)

A pair of bearing housings arranged to face each other in the axial direction,
A rotating shaft rotatably supported by the pair of bearing housings via bearings,
A ring-shaped permanent magnet fixed to the outer periphery of the rotating shaft and magnetized in the axial direction;
A pair of rotor cores fixed to both end surfaces in the axial direction of the permanent magnet and each having a plurality of rotor pole teeth on the outer periphery thereof, and integrally rotating with the rotation shaft;
A yoke portion which is divided into a plurality in the circumferential direction and is arranged so as to have a cylindrical shape surrounding the pair of rotor cores, and is sandwiched between the pair of bearing housings, and an inner peripheral portion of the yoke portion. Provided, a plurality of split stator cores provided with a stator magnetic pole having a plurality of stator pole teeth opposed to each other from the radial direction via the rotor pole teeth and a gap at the tip,
A hybrid type stepping motor, comprising: a plurality of coils wound around the stator poles, respectively. The hybrid stepping motor according to claim 1, wherein each of the split stator cores is formed by an integral structure of a high-permeability soft magnetic material. 3. The hybrid stepping motor according to claim 1, wherein each of the split stator cores is formed by sintering. When assembling the hybrid stepping motor according to any one of claims 1 to 3,
A permanent magnet magnetized in the axial direction, and disposed on both end surfaces in the axial direction of the permanent magnet, and an outer peripheral surface is formed on an outer peripheral portion along a tip end surface of a stator pole tooth in the split stator core, and has a circumferential width. A positioning jig provided with a pair of positioning members made of a magnetic material having a plurality of protrusions formed so as to have substantially the same width as the width of the tip of the stator magnetic pole,
A plurality of the divided stator cores are arranged and positioned around the positioning jig by attracting a tip end surface of the stator pole teeth to an outer peripheral surface of each of the projections of the positioning jig, and thereafter, A method of assembling a hybrid type stepping motor, wherein the plurality of split stator cores are sandwiched between the pair of bearing housings. 4. An optical device having an optical member such as a laser light source or a lens, wherein the hybrid type stepping motor according to claim 1 is used as driving means for the optical member.

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