JP4119797B2 - Stator structure of claw pole type stepping motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a stator structure of a claw pole type stepping motor, and more particularly, to a reduction in diameter, high performance, and low cost by a method of constructing the stator.
[0002]
[Prior art]
In recent years, there has been remarkable progress in improving the performance of various devices, especially in miniaturization, and in connection with this, various devices use a plurality of dedicated motors according to their functions. In particular, in a portion that requires position control, although the use of a stepping motor is suitable, there is a limit to the miniaturization of the motor and it cannot be adopted.
[0003]
7A and 7B are views showing a stator structure of a conventional claw pole type stepping motor, in which FIG. 7A is a perspective view with a part in cross section, and FIG. 7B is an enlarged perspective view of pole teeth.
[0004]
In FIG. 7, reference numeral 1 denotes an upper flange for mounting a motor, and an outer yoke 2 has pole teeth 4 on its inner periphery by processing a soft magnetic steel sheet. Similarly, the inner yoke 3 has a pole tooth 4 on the inner periphery of a soft magnetic steel sheet. These yokes 2 and 3 constitute a pancake 15 by sandwiching a coil 6 around which a magnet wire is wound around a bobbin 5 and combining the pole teeth 4 on the inner circumference so as to face each other. In this way, the two pancakes 15 including the coil 6 and the yokes 2 and 3 are back to back to constitute a stator. A lower flange 7 is attached to the outer yoke 2 of the pancake 15 on the lower side in the drawing with a bearing 8 disposed at the center. Reference numeral 9 denotes a rotor magnet, and the sleeve 10 connects the rotor magnet 9 and a shaft 11 which is the rotation center of the rotor.
[0005]
FIG. 8 is a cross-sectional view of a pancake used in the claw pole type stepping motor of FIG.
[0006]
Looking at the configuration of the pole teeth 4 in the pancake 15 of FIG. 8, the pole teeth 4 are formed by drawing on the inner circumferences of the respective yokes 2, 3. Is thinner and more prone to bending and falling.
[0007]
[Problems to be solved by the invention]
As described above, in the claw pole type stepping motor, the yokes 2 and 3 and the pole teeth 4 are integrally formed. Therefore, the smaller the diameter, the smaller the plate thickness of the material from the viewpoint of securing coil space and workability. In addition, the height of the pole teeth is shortened, making it extremely difficult to manufacture, and at the same time, the motor characteristics have been steadily decreasing, and the outer diameter of 8 mm has become the limit for reducing the diameter. For this reason, an encoder that is a position detector is added to the DC motor to perform position control, resulting in an expensive configuration. However, in the environment surrounding the stepping motor, a high-performance magnet such as a rare earth magnet has been developed for the rotor magnet facing the stator, and there is a foundation that can improve the characteristics of the motor as long as the stator can be processed. An appropriate configuration method has been demanded.
[0008]
The present invention has been made in view of such problems, and an object of the present invention is to provide a stator structure capable of coping with a reduction in the diameter of a claw pole type motor and a high performance.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a stator structure of the present invention is a claw pole type stepping motor comprising a stator that forms a magnetic circuit with a yoke obtained by processing a soft magnetic steel plate, and a rotor that is inserted into the stator and rotates. In this stator structure, a plurality of pole teeth made of a soft magnetic material are provided so as to face the rotor magnet of the rotor, and the pole teeth are configured as separate parts from the yoke, and the yoke is a cylindrical yoke having a rounded plate. And a disc-shaped yoke disposed at both ends of the cylindrical yoke, and a winding bobbin made of a polymer material is provided, and the pole teeth are arranged on the inner periphery of the bobbin, and the bobbin but a plurality of guide grooves for holding the polar teeth as well as the positioning of the bobbin for each of a plurality of pole teeth arranged on the inner circumference, are fitted with the disk-shaped yoke before and the disk-shaped yoke And a guide portion for holding the disk-shaped yoke as well as the positioning of the polar teeth held in the guide groove, the guide groove, than the length of the polar teeth held in the guide groove a stopper having a spring property so that the length of the guide groove becomes short provided, contact the polar teeth of the pinched polar teeth and said disk-shaped yoke between said stopper and said disk-shaped yoke The guide portion serves also as a holding portion for the pole teeth.
[0010]
The stator structure of the present invention is characterized in that when the plate thickness of the pole teeth is T1, and the plate thickness of the disk-shaped yoke is T2, the respective relationships are T1 ≧ T2.
[0011]
Further, the stator structure of the present invention is characterized in that when the axial length of the pole teeth is L and the rotor diameter is D, each relationship is L ≧ D / 2.
[0012]
The stator structure according to the present invention is characterized in that a press-fit portion is formed at an end portion of the pole tooth , and the press-fit portion is press-fitted and fixed to the disk-shaped yoke.
[0013]
Further, the stator structure of the present invention is characterized in that the guide portions are disposed on both end surfaces of the bobbin and are connected to the stopper portion.
[0014]
Further, a claw pole type stepping motor of the present invention has any one of the stator structures described above.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described below with reference to the drawings.
[0016]
1A and 1B are views showing a stator structure of a claw pole type stepping motor according to the present invention, in which FIG. 1A is a perspective view with a part in cross section, and FIG. 1B is an enlarged perspective view of pole teeth.
[0017]
The schematic configuration of the stator structure according to the present invention is as follows. The pole teeth 4 are separated from the stator yokes 2 and 3 so that they are not affected by the rotor diameter and the stator yokes 2 and 3 thickness. As the width and thickness, the yokes 2, 3 provided on both end faces of the bobbin 5 are inserted into a plurality of (four in the case of an 8-step motor) grooves 12 provided on the inner peripheral surface of the winding bobbin. It was constituted so as to come into contact alternately. In addition, guide parts 13 are provided on both end faces of the bobbin 5, and the positions of the yokes 2, 3 and the pole teeth 4 are determined by fitting the guide parts 13 with the yokes 2, 3. Yes. Therefore, it is possible to easily configure a small-diameter product or a long-sized stator in which the pole teeth 4 are difficult to configure, and at the same time, the cross-sectional area of the pole teeth 4 can be arbitrarily set, so that the pole teeth 4 do not cause magnetic saturation. High output is obtained. Further, since the arrangement (assignment) of the pole teeth 4 in the bobbin 5 is determined, the arrangement of the pole teeth 4 that determines the step angle accuracy can be performed with high accuracy without being disturbed, and the step angle accuracy can be increased. . Further, if a hole is provided in each of the yokes 2 and 3 as a fixing method of the pole teeth 4 and the pole teeth 4 are press-fitted and fixed there, the connection strength between the pole teeth 4 and the yokes 2 and 3 is improved and at the same time magnetically. Bonding is stable and both workability and characteristics can be improved.
[0018]
In the embodiment of the present invention shown in FIG. 1, reference numeral 1 represents an upper flange for mounting a motor, 2 represents an outer yoke obtained by sheet metal processing of a soft magnetic steel sheet, and 3 represents an inner yoke obtained by sheet metal processing of a soft magnetic steel sheet. . The bobbin 5 around which the magnet wire is wound between the yokes is provided with pole teeth 4 on the inner periphery thereof, and the bobbins 5 are alternately in contact with the yokes. These yokes 2 and 3 are combined so that a coil 6 in which a magnet wire is wound around a bobbin 5 is sandwiched between them and pole teeth 4 on the inner periphery face each other. In this way, the stator is configured with the pancakes 15 combined with the yokes 2 and 3 back to back. Reference numeral 7 denotes a lower flange, which is mounted with a bearing 8 disposed in the center. Reference numeral 9 denotes a rotor magnet, and reference numeral 10 denotes a sleeve that connects the rotor magnet and a shaft 11 serving as a rotation center of the rotor. The rotor magnet 9, the sleeve 10 and the shaft 11 constitute a rotor, which is inserted into the center of the stator and rotates.
[0019]
Here, regarding the configuration of the pole teeth 4, the pole teeth 4 are configured to have a plate thickness larger than the plate thickness of each of the yokes 2 and 3 so that a sufficient cross-sectional area can be obtained as necessary in the magnetic circuit. That is, when the plate thickness of the pole teeth 4 is T1, and the plate thickness of the yokes 2 and 3 is T2, the relationship between them is T1≥T2, and the length of the pole teeth 4 in the axial direction is L, the rotor When the diameter of each is D, by setting each relationship to L ≧ D / 2, it is possible to avoid magnetic saturation and improve the motor characteristics.
[0020]
2 is a cross-sectional view of the pancake of FIG. 1, and FIG. 3 is an explanatory view of the bobbin.
[0021]
2 and 3, four guide grooves 12 for holding the pole teeth 4 (straight type) are equally arranged in the circumferential direction. The guide groove 12 is provided with a stopper 14 having a spring property at a portion corresponding to the tip of the pole tooth 4. Therefore, by setting the length of the guide groove 12 slightly shorter than the length of the pole teeth 4 in the axial direction, the pole teeth 4 and the yoke 2 or 3 can be in stable contact even if the length of each of the guide grooves 12 varies slightly. A good stator configuration can be obtained. Further, guides 13 are arranged on both upper and lower end faces. The guide 13 is fitted to each yoke to determine the position of the pole teeth 4.
[0022]
FIG. 4 is a diagram showing examples of various shapes of pole teeth. a is a triangular shape, b is a straight shape, c is a trapezoidal shape, d is a grooved shape, e is a reverse sled shape, and f is a stepped shape. Of course, any shape other than these is included in the scope of the present invention.
[0023]
FIG. 5 is a view showing a modification of the yoke. The ring-shaped yoke 16 and the disk-shaped inner yoke 3 are used. The ring-shaped yoke 16 is configured by rolling a plate into a cylindrical shape. Since this construction does not require drawing, the working speed is remarkably improved and the durability of the mold is increased, thereby reducing the cost.
[0024]
FIG. 6 is a view showing a modification of the lower flange of the present invention, in which the left half is a front view and the right half is a cross-sectional view.
[0025]
FIG. 6 shows a lower flange 17 constituted by an insert mold. In this case, the press-fitting portion 20 provided on the pole teeth 4 is press-fitted and fixed to the yokes 2 and 3 and then integrated by an insert mold, so that the present invention is further improved than when the pole teeth 4 are provided on the inner periphery of the bobbin 5. The effect of can be demonstrated. A fitting state between the yokes 2 and 3 and the pole teeth 4 is shown in an enlarged view of A part. In addition, the shape of the fitting press-fit portion 20 is not limited to this, and various modified types are conceivable. Of course, these modified types are also included in the scope of the present invention.
[0026]
【The invention's effect】
According to the present invention, in a stator structure of a claw pole type stepping motor comprising a stator that forms a magnetic circuit with a yoke obtained by processing a soft magnetic steel plate, and a rotor that is inserted into the stator and rotates, Since the pole teeth made of soft magnetic material configured as a separate part are provided on the inner periphery of the bobbin made of polymer material, the stator can be configured even with a small diameter, and the dimensions of the pole teeth can be set freely, Small and long motors that were impossible until now can be configured, and high-performance motors with good magnetic efficiency can be configured at low cost.
[Brief description of the drawings]
1A and 1B are views showing a stator structure of a claw pole type stepping motor according to the present invention, in which FIG. 1A is a perspective view with a part in cross section, and FIG. 1B is an enlarged perspective view of pole teeth.
FIG. 2 is a cross-sectional view of the pancake of FIG.
FIG. 3 is an explanatory diagram of a bobbin of the present invention.
FIG. 4 is a perspective view showing examples of various shapes of pole teeth according to the present invention.
FIG. 5 is a view showing a modification of the yoke of the present invention.
FIG. 6 is a view showing a modification of the lower flange of the present invention, in which the left half is a front view and the right half is a cross-sectional view.
7A and 7B are views showing a stator structure of a conventional claw pole type stepping motor, in which FIG. 7A is a perspective view with a part in cross section, and FIG. 7B is an enlarged perspective view of pole teeth.
8 is a cross-sectional view of the pancake of FIG.
[Explanation of symbols]
Reference Signs List 1 upper flange 2 outer yoke 3 inner yoke 4 pole tooth 5 bobbin 6 coil 7 lower flange 8 bearing 9 rotor magnet 10 sleeve 11 shaft 12 guide groove 13 guide 14 stopper 15 pancake 16 ring-shaped yoke 17 lower flange 20 press-fit part

Claims (6)

In a stator structure of a claw pole type stepping motor comprising a stator that forms a magnetic circuit with a yoke obtained by processing a soft magnetic steel plate, and a rotor that is inserted into the stator and rotates.
A plurality of pole teeth made of a soft magnetic material facing the rotor magnet of the rotor, the pole teeth being configured as a separate part from the yoke,
The yoke is composed of a cylindrical yoke with a rounded plate, and disc-shaped yokes disposed at both ends of the cylindrical yoke,
A bobbin for winding made of a polymer material is provided, and the pole teeth are arranged on the inner periphery of the bobbin,
Said bobbin, a plurality of guide grooves for holding the polar teeth as well as the positioning of the bobbin for each of a plurality of pole teeth arranged on the inner circumference, the disc-shaped yoke and engaging with said disk-shaped yoke and a guide portion for holding the disk-shaped yoke as well as the positioning of the polar teeth held in the guide groove and,
The said guide groove is provided with a stopper having a spring property so that the length of the guide groove than the length of the polar teeth held in the guide groove becomes shorter, polar teeth said stopper and said disk-shaped contact pinched polar teeth and said disk-shaped yoke between the yoke so as to stabilize,
A stator structure of a claw pole type stepping motor, wherein the guide portion also serves as a holding portion for the pole teeth. 2. The stator of a claw pole type stepping motor according to claim 1, wherein when the pole tooth thickness is T1, and the thickness of the disk-shaped yoke is T2, each relation is T1 ≧ T2. Construction. 2. The stator of a claw pole type stepping motor according to claim 1, wherein when the axial length of the pole teeth is L and the diameter of the rotor is D, each relationship is L ≧ D / 2. Construction. The stator structure of a claw pole type stepping motor according to claim 1, wherein the pole teeth are integrated with the bobbin by an insert mold. 2. The stator structure of a claw pole type stepping motor according to claim 1, wherein a press-fit portion is formed at an end portion of the pole tooth , and the press-fit portion is press-fitted and fixed to the disk-shaped yoke. 2. The stator structure of a claw pole type stepping motor according to claim 1, wherein the guide portion is disposed on both end faces of the bobbin and is provided so as to be connected to the stopper portion.

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