JP2000092810A - Stepping motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the thickness of a stepping motor and improve the rotation response of the rotor of the motor. SOLUTION: The rotor of a stepping motor 10 is formed as a platy disk rotor 20 having magnetic poles formed on its both side faces spread in the direction perpendicular to the axial line of the rotating shaft of the motor 10, and the stator of the motor 10 is constituted of a first stator group 30 and a second stator group 40 arranged at an interval. The first and second stator groups 30 and 40 are respectively constituted of a pair of first platy yokes 31a and 31b and a pair of second tabular yokes 41a and 41b respectively having pole teeth 31a' and 31b' and 41a' and 41b' which are arranged on both sides of the disk rotor 20 in such a way that the teeth 31a', 31b', 41a', and 41b' are extended toward the center of the rotating shaft in parallel with both side faces of the rotor 20 at regular pitches in the peripheral direction of the rotor 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a PM (permanent magnet)
More particularly, the present invention relates to a stepping motor using a disc-shaped disk rotor as a rotor.

[0002]

2. Description of the Related Art As a conventional stepping motor used for a drive unit of a home electric appliance, a drive unit of an indicating instrument of a car or the like, for example, Japanese Unexamined Patent Publication No.
There is one disclosed in JP-A-9-19126 and the like. As shown in FIG. 12, this stepping motor has a columnar rotor 2 made of a permanent magnet fixed to a rotating shaft 1, and a first magnetic pole surface 2 a and a second magnetic pole surface formed on the outer peripheral surface of the rotor 2. 2b, an annular first stator 3 and a second annular
And a stator 4 as its basic configuration.

[0003] The first stator 3 and the second stator 4 have an annular first bobbin 3a having a rectangular cross section.
And a first stator coil 3b and a second stator coil 4b disposed in the second bobbin 4a, respectively, and a first annular member having a rectangular cross section and disposed so as to surround the first bobbin 3a and the second bobbin 4a, respectively. The inner surface of each of the first yoke 3c and the second yoke 4c is formed by a yoke 3c and a second yoke 4c. Pole teeth 3d and 4d are formed.

That is, the pole teeth 3d of the first stator 3 are
The first magnetic pole surface 2a formed on the outer peripheral surface of the rotor 2 is opposed, and the pole teeth 4d of the second stator 4 are opposed to the second magnetic pole surface 2b formed on the outer peripheral surface of the rotor 2. The first stator 3 and the second stator 4 are aligned with the axis L of the rotating shaft 1.
The structure is stacked in the direction.

[0005]

In the conventional stepping motor, the first stator 3 and the second
Since the stator 4 and the stator 4 are stacked in the direction of the axis L of the rotating shaft 1, the thickness in the direction of the rotating shaft 1 becomes large, and the stepping motor cannot be arranged in a region where the depth is small. was there.

Further, since the first stator 3 and the second stator 4 are stacked, there is a problem that magnetic leakage easily occurs between the two.

Further, since the rotor 2 is formed in a cylindrical shape so as to have the first magnetic pole surface 2a and the second magnetic pole surface 2b on its outer peripheral surface, the rotor 2 has a structure with a large moment of inertia. As a result, there is a problem that the rotation response of the rotor 2 itself is poor.

Further, the pole teeth 3d, 4d formed on the first yoke 3c and the second yoke 4c of the first stator 3 and the second stator 4 are formed by punching and bending a flat iron plate. In addition, there is a problem that the distance between the pole teeth 3d or 4d varies, and the step angle of the rotor 2 cannot be set uniformly.

The present invention has been made in view of the above-mentioned problems of the prior art, and it is an object of the present invention to reduce the size of a stepping motor as a whole, particularly to reduce the thickness in the thickness direction, and to reduce the magnetic field. It is an object of the present invention to provide a stepping motor capable of reducing the leakage of the rotor, improving the rotational responsiveness of the rotor, and increasing the accuracy of the angular position of the rotor.

[0010]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventor has come to find an invention having the following configuration. That is, a stepping motor according to the present invention includes a rotor fixed to a rotating shaft and having a magnetic pole, a stator having an exciting coil and a yoke for guiding a magnetic field of the exciting coil, and an exciting coil formed on the pole teeth of the yoke. A stepping motor for rotating the rotor by a predetermined angle by a magnetic attraction force and a repulsive force between a pole and a magnetic pole of the rotor, wherein the rotor has surfaces on both sides extending in a direction perpendicular to the axis of the rotation shaft. The stator includes a first stator group and a second stator group spaced from each other in the circumferential direction of the disk rotor, and the first stator group Are arranged so as to sandwich the disk rotor, and are respectively parallel to both surfaces of the disk rotor and directed toward the center of the rotation axis. And a pair of first flat yokes each having a plurality of pole teeth formed at equal pitch intervals in the circumferential direction of the disk rotor, and a first excitation for forming a magnetic field in the pair of first flat yokes. And a second stator group,
A plurality of disks are arranged so as to sandwich the disk rotor, extend in parallel to both surfaces of the disk rotor and toward the center of the rotation shaft, and are formed at equal pitch intervals in the circumferential direction of the disk rotor. A pair of second plate-shaped yokes each having a pair of pole teeth;
And a second excitation coil for forming a magnetic field on the flat yoke.

In the stepping motor having the above configuration, a plurality of the first exciting coils and a plurality of the second exciting coils are provided between the pair of the first plate-shaped yokes and the pair of the second plate-shaped yokes, respectively. Can be adopted.

In the stepping motor having the above configuration, the pair of first flat yoke and the pair of second flat yoke are provided.
The plate-like yoke has a configuration in which the separation distance in the region where the first excitation coil and the second excitation coil are arranged is larger than the separation distance in the region of the pole teeth sandwiching the disk rotor. can do.

In the stepping motor having the above configuration, a configuration in which the disk rotor is formed using a powder magnet and a resin material can be employed. In the stepping motor having the above configuration, the pole teeth are
A configuration formed in a substantially rectangular shape can be adopted.

In the stepping motor having the above configuration, it is possible to employ a configuration in which a stopper for stopping the disk rotor at a predetermined rotation angle position is provided.
In the stepping motor having the above configuration, the stepping motor may include a surrounding cover surrounding the disk rotor and the stator, and the surrounding cover may have a configuration in which an area where the stopper is attached is at least transparent.

According to the stepping motor having the above configuration, the plurality of pole teeth formed on the pair of first flat yoke are respectively provided on both sides of the flat disk rotor, that is, on both pole faces. Since it is formed so as to extend in parallel, a magnetic attractive force or a repulsive force is generated between the exciting poles formed on the plurality of pole teeth and the magnetic poles of the disk rotor. Further, a plurality of pole teeth formed on the pair of second flat yoke are formed so as to extend in parallel with both surfaces of the flat disk rotor, that is, with both magnetic pole surfaces. Accordingly, a magnetic attractive force or a repulsive force is generated between the excitation poles generated on the plurality of pole teeth and the magnetic poles of the disk rotor.

When the first excitation coil and the second excitation coil are respectively energized at a predetermined timing and in a predetermined direction, the first stator group and the second stator group rotate the disk rotor by a predetermined angle. Act on.

In the stepping motor having the above structure, a plurality of the first exciting coils and the second exciting coils are provided between the pair of the first plate-shaped yokes and the pair of the second plate-shaped yokes, respectively. The plurality of first excitation coils and the second excitation coils efficiently generate excitation poles with respect to the pole teeth formed on the pair of first plate-shaped yokes and the pair of second plate-shaped yokes, respectively. Act like so.

In the stepping motor having the above configuration, the pair of first plate-shaped yokes and the pair of second plate-shaped yokes are each compared with the first excitation coil and the pair of second plate-shaped yokes with respect to the separation distance of the pole teeth region sandwiching the disk rotor. In the case where the separation distance of the region where the second excitation coil is disposed is increased, the number of turns of the first excitation coil and the second excitation coil can be increased by the distance, and on the other hand, the disk Since a predetermined interval is maintained in the portion of the pole teeth sandwiching the rotor, an excitation pole is efficiently generated by the first excitation coil and the second excitation coil. A magnetic attractive force or a repulsive force is generated between the magnetic poles.

In the stepping motor having the above structure, when the disk rotor is formed by using a powder magnet and a resin material, the disk rotor itself is light in weight, the moment of inertia is reduced, and the disk rotor responds. It works so as to perform rotational movement with good efficiency.

In the stepping motor having the above configuration, when the pole teeth are formed in a substantially rectangular shape, a portion of the substantially rectangular pole teeth facing the magnetic pole surface of the disk rotor acts as an excitation pole. I do.

In the stepping motor having the above structure, when a stopper for stopping the disk rotor at a predetermined rotation angle position is provided, the stopper acts to stop the disk rotor at the predetermined rotation angle position.

In the stepping motor having the above-described structure, the stepping motor has a surrounding cover surrounding the disk rotor and the stator, and when the portion of the surrounding cover to which the stopper is attached is at least transparent, the stepping motor surrounds the disk rotor and the stator. When the surrounding cover is assembled in such a manner as described above, and then the stopper is inserted and attached at a desired position, the transparent portion functions as a window for visually recognizing the inside.

[0023]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a first embodiment of a stepping motor according to the present invention, wherein (a)
Is a plan view in which some components (an upper surrounding cover 62 described later) are omitted, and FIG. As shown in FIG. 1, a stepping motor 10 according to this embodiment is a flat disk rotor 20 fixed to a rotating shaft 11 and having magnetic poles on both sides extending in a direction perpendicular to the axis of the rotating shaft.
And a first stator group 30 and a second stator group 4 that are spaced from each other in the circumferential direction of the disk rotor 20.
0 as a basic configuration.

As shown in FIG. 2, the disk rotor 20 has a circular hole 20a at the center thereof and has an outer contour formed in a circular flat plate shape, and has one surface 20b and the other surface 20c. In the present embodiment, N poles and S poles, which are magnetic poles, are alternately arranged in the circumferential direction (in this embodiment, a total of 48 poles on one side), and are further formed on one side 20b and on the other side. The magnetic poles are arranged such that the N pole and the S pole face each other. The disk rotor 20 is formed by molding a magnet powder of a rare earth element or a ferrite material into a disk shape from a resin material, that is, by molding a plastic material, and is multipolar magnetized in its thickness direction. When formed using a resin material in this manner, the moment of inertia can be reduced, and the rotational response of the disk rotor 20 itself can be improved.

The disk rotor 20 is arranged as shown in FIG.
As shown in (b), a circular hole 20 is formed in a small-diameter portion 12a of a flange member 12 having a two-stage configuration of a small-diameter portion 12a and a large-diameter portion 12b fixed to a steel rotating shaft 11 by press fitting.
is fixed by press-fitting the external fixing member a into the small-diameter portion 12a through the circular hole 13a, and the annular fixing member 13 and the large-diameter portion 12b of the flange member 12 are fixed to each other. By being sandwiched, the rotating shaft 11 is fixed so as to prevent the rotating shaft 11 from moving in the direction of the axis L.

Here, by forming the flange member 12 and the annular fixing member 13 from a nonmagnetic material such as aluminum, it is possible to secure a predetermined fixing strength while suppressing the inertia moment. In addition, when the annular fixing member 13 and the flange member 12 made of these nonmagnetic materials are arranged in a molding die, and the disk rotor 20 is molded from a resin material using the above-mentioned magnet powder, the whole is integrally insert-molded. It is also possible,
Under application conditions in which the load applied to the rotating shaft is relatively small, these annular fixing member 13, flange member 12,
In addition to the disk rotor 20 and the rotary shaft 11, the rotary shaft 11 may be integrally formed of a resin material.

The above-mentioned stators are spaced apart in the circumferential direction of the disk rotor 20, that is, at a position separated by an angle of about 180 °, the first stator group 30 being opposed to each other so as to sandwich the disk rotor 20. And the second stator group 40.

The first stator group 30 includes an upper plate-like yoke 31a and a lower plate-like plate 31 which are arranged so as to sandwich the outer peripheral region of the disk rotor 20 at a predetermined interval to form a pair of first plate-like yokes 31. Exciting coil 33 wound around an iron core 32 between the upper yoke 31b and the upper flat yoke 31a and the lower flat yoke 31b.
, And is constituted.

The upper plate-like yoke 31a and the lower plate-like yoke 31b are formed by subjecting a plate made of a highly magnetically permeable material such as permalloy, silicon steel, iron or the like to press molding or the like. A substantially rectangular shape which is arc-shaped and whose inner peripheral area is parallel to both surfaces (magnetic pole surfaces) 20b and 20c of the disk rotor 20 and is tapered toward the center of the rotating shaft 11, respectively. It is formed in a comb shape having a plurality of pole teeth 31a ', 31b'.

The pole teeth 31a 'and 31b' are
In the range of a central angle of less than 180 ° with respect to one rotation center, they are formed at equal pitch intervals in the circumferential direction of the disk rotor 20. In the present embodiment, the disk rotor 20
Since the number of poles is 48, that is, 24 pitches, 11 pitches are formed with the pitch interval as the central angle of 15 °.

A spacer 50 is arranged between the upper plate-like yoke 31a and the lower plate-like yoke 31b so that they are held at a predetermined distance in an assembled state. The spacer 50 is formed of a non-magnetic material, has a substantially rectangular outline, and has a circular hole 50 at the center thereof for allowing the disk rotor 20 to be arranged.
a is provided.

The first exciting coil 33 is a bobbin 3 made of a non-magnetic material fixed to an iron core 32 made of soft iron.
4 and wound around the iron core 32,
2 is an upper flat yoke 31a and a lower flat yoke 3
It is fixed by being fitted into a mounting hole H formed in 1b.

The first stator group 3 configured as described above
0 denotes a magnetic field of the first exciting coil 33 that is energized when the pole teeth 31a 'and the pole teeth 31b' are arranged so as to sandwich the disk rotor 20, with a predetermined interval between the pole faces 20b and 20c. Are the iron core 32 and the upper flat yoke 3
1a and the lower flat yoke 31b to form a magnetic path, and an excitation pole is generated at the pole teeth 31a 'and 31b'. For example, when the pole tooth 31a 'is the N pole, the pole tooth 31b' is formed. Is formed on the S pole, and when the pole tooth 31a 'is the S pole, the pole tooth 31b' is formed on the N pole.

Then, as described above, the pole teeth 31a ', 31
A magnetic attractive force and a repulsive force are generated between the excitation pole generated at b ′ and the magnetic poles formed on the magnetic pole surfaces 20b and 20c of the disk rotor 20.

On the other hand, the second stator group 40 corresponds to FIG.
As shown in (a), from a position 180 ° away from the center of rotation about the center of rotation of the rotating shaft 11, a further step angle, that is, 中心 pitch (3.75 ° at center angle θ; θ = (36
0 ° / 24 pitch) / 4).
It is arranged so as to face the stator group 30.

Similar to the first stator group 30, the second stator group 40 is disposed so as to sandwich the outer peripheral region of the disk rotor 20 at a predetermined interval, and a pair of second stator groups 40 is provided.
An upper flat yoke 41a and a lower flat yoke 41b forming the flat yoke 41;
1a and the lower flat yoke 41b,
And a second exciting coil 43 wound around the second exciting coil 43.

The upper plate-like yoke 41a and the lower plate-like yoke 41b are formed by subjecting a plate made of a highly magnetically permeable material such as permalloy, silicon steel, iron or the like to press molding or the like. A substantially rectangular shape which is arc-shaped and whose inner peripheral area is parallel to both surfaces (magnetic pole surfaces) 20b and 20c of the disk rotor 20 and is tapered toward the center of the rotating shaft 11, respectively. It is formed in a comb shape having a plurality of pole teeth 41a ', 41b'.

The pole teeth 41a ', 41b' are
In the range of a central angle of less than 180 ° with respect to one rotation center, they are formed at equal pitch intervals in the circumferential direction of the disk rotor 20. In the present embodiment, the disk rotor 20
Since the number of poles is 48, that is, 24 pitches, 11 pitches are formed with the pitch interval as the central angle of 15 °.

The above-described spacer 50 is arranged between the upper plate-like yoke 41a and the lower plate-like yoke 41b so that they are held at a predetermined distance in an assembled state. .

The second exciting coil 43 is composed of a bobbin 4 made of a non-magnetic material externally fixed to an iron core 42 made of soft iron.
4 and is wound around the iron core 42.
2 is an upper flat yoke 41a and a lower flat yoke 4
It is fixed by being fitted into a mounting hole H formed in 1b.

The second stator group 4 configured as described above
0 denotes a magnetic field of the second exciting coil 43 which is energized in such a manner that the pole teeth 41a 'and the pole teeth 41b' are arranged so as to sandwich the disk rotor 20 at predetermined intervals between the pole faces 20b and 20c. Are the iron core 42 and the upper flat yoke 4
1a and the lower flat yoke 41b to form a magnetic path, and an excitation pole is generated at the pole teeth 41a 'and 41b'. For example, when the pole tooth 41a 'is the N pole, the pole tooth 41b' is formed. Is formed on the S pole, and when the pole tooth 41a 'is the S pole, the pole tooth 41b' is formed on the N pole.

Then, as described above, the pole teeth 41a ', 41
A magnetic attractive force and a repulsive force are generated between the excitation pole generated at b ′ and the magnetic poles formed on the magnetic pole surfaces 20 b and 20 c of the disk rotor 20.

The disk rotor 20, the first stator group 30, and the second stator group 40 are housed in a surrounding case 60 composed of a lower surrounding case 61 and an upper surrounding case 62 formed of a resin material or the like. ing. The lower surrounding case 61 and the upper surrounding case 62 are provided with bearings 61a and 62a, respectively.
The rotating shaft 11 is rotatably supported by a and 62a.

Next, the operation of the stepping motor 10 according to this embodiment will be described. FIG. 3 shows a drive voltage waveform applied to the excitation coils 33 and 43 when the disk rotor 20 is driven to rotate forward by one-phase excitation. In the case of this driving method, the disk rotor 20 at the initial position as shown in FIG.
0 is excited, the pole teeth 31a 'and 31b' and the magnetic pole surface 2 of the disk rotor 20 are excited.
A magnetic attraction force is generated between 0b and 20c, and rotates by ８ pitch as shown in FIG.

Subsequently, the excitation of the first excitation coil 33 is released, and the second excitation coil 43 of the second stator group 40 is excited, so that the pole teeth 41 a ′ and 41 b ′ and the magnetic pole surface of the disk rotor 20. A magnetic attraction force is generated between 20b and 20c, and as shown in FIG. 4C, the disk rotor 20 further rotates by 1/4 pitch.

Next, the excitation of the second excitation coil 43 is released, and the first excitation coil 33 of the first stator group 30 is excited in the opposite direction, so that the pole teeth 31a 'and 31b' and the disk rotor 20 are turned off. A magnetic attraction force is generated between the magnetic pole surfaces 20b and 20c of FIG. 4, and as shown in FIG.
The disk rotor 20 further rotates by 1/4 pitch.

Subsequently, the excitation of the first excitation coil 33 is released, and the second excitation coil 43 of the second stator group 40 is excited in the opposite direction, so that the pole teeth 41a 'and 41b'.
A magnetic attractive force is generated between the magnetic poles 20b and 20c of the disk rotor 20, and the disk rotor 20 further rotates by a quarter pitch as shown in FIG.

By continuously performing the above driving operation by a predetermined step amount, the disk rotor 20 rotates forward by a predetermined angle. When the disk rotor 20 is driven to rotate in the reverse direction by one-phase excitation, a drive voltage having a waveform as shown in FIG. 5 may be applied to the excitation coils 33 and 43 for driving.

FIG. 6 shows a drive voltage waveform applied to the excitation coils 33 and 43 when the disk rotor 20 is driven to rotate forward by two-phase excitation. In the case of this driving method, in the disk rotor 20 at the initial position as shown in FIG. 7A, the first excitation coil 33 of the first stator group 30 and the second excitation coil 43 of the second stator group 40 are the same. The pole teeth 31a ', 3
1b 'and pole teeth 41a', 41b 'and disk rotor 2
A magnetic attractive force is generated between the 0 magnetic pole surfaces 20b and 20c, and the magnetic pole rotates by a 1/4 pitch as shown in FIG. 7B.

Subsequently, while the second exciting coil 43 of the second stator group 40 is excited in the above-described direction, the first exciting coil 33 of the first stator group 30 is excited in the opposite direction, thereby The magnetic attraction generated between the teeth 31a 'and 31b' and the magnetic pole surfaces 20b and 20c of the disk rotor 20 acts particularly, and as shown in FIG. Rotate by 4 pitches.

Next, while the first exciting coil 33 of the first stator group 30 is excited in the above-described reverse direction, the second exciting coil 43 of the second stator group 40 is excited in the opposite direction. The magnetic attraction generated between the pole teeth 41a 'and 41b' and the magnetic pole surfaces 20b and 20c of the disk rotor 20 acts particularly, and as shown in FIG. Rotate by 1/4 pitch.

Subsequently, in a state where the second excitation coil 43 of the second stator group 40 is excited in the above-described opposite direction, the first
When the first excitation coil 33 of the stator group 30 is excited in the original direction, the magnetic attraction generated between the pole teeth 31a 'and 31b' and the magnetic pole surfaces 20b and 20c of the disk rotor 20 is particularly increased. As a result, as shown in FIG. 7E, the disk rotor 20 further rotates by １ ／ pitch.

By continuously performing the above driving operation by a predetermined step amount, the disk rotor 20 rotates forward by a predetermined angle. When the disk rotor 20 is driven to rotate in the reverse direction by two-phase excitation, a drive voltage having a waveform as shown in FIG. 8 may be applied to the excitation coils 33 and 43 for driving.

FIG. 9 shows a stepping motor according to a second embodiment of the present invention. FIG. 9A is a plan view in which some parts (an upper surrounding cover 162 described later) are omitted.
(B) is a longitudinal sectional view. As shown in FIG. 9, the stepping motor 100 according to this embodiment
A plate-shaped disk rotor 120 having magnetic poles on both side surfaces, which is fixed to and extends in a direction perpendicular to the axis of the rotation shaft;
The first stator group 130 and the second stator group 1 arranged at intervals in the circumferential direction of the disk rotor 120.
And a stator composed of a base member 40, which is different from the first embodiment in that an annular fixing member 113 for clamping and fixing the disk rotor 120, an upper surrounding cover 162 forming one of the surrounding covers 160, and an additional stopper 170 are provided. Except for the above, the third embodiment is the same as the first embodiment, and the description of the same portions will be omitted.

The stepping motor 100 of this embodiment
In the embodiment, the annular fixing member 113 for clamping and fixing the disk rotor 120 to the rotating shaft 110 is formed in a disk shape having a smaller outer diameter than that of the first embodiment, The portion is integrally formed with a protrusion 113a protruding radially outward.

The upper surrounding cover 162 constituting one of the surrounding covers 160 is formed entirely of a transparent resin material so that the inside can be visually recognized. A circular hole 162b having a counterbore is formed in a part of the upper surface, and a stopper 17 is formed in the circular hole 162b.
0 is fitted.

The stopper 170 is provided on the upper surrounding cover 1.
62 is formed by a flange portion 170a that comes into contact with the counterbore portion 62 and a cylindrical stopper portion 170b that is pressed into the circular hole 162b of the upper surrounding cover 162. The outer peripheral surface of the stopper portion 170b is
a can be brought into contact with the side surface.

As described above, since the upper surrounding cover 162 is formed of a transparent material, the stopper 17
In order to prevent the tip of the stopper portion 170b from colliding with the protrusion 113a of the annular fixing member 113, the upper surrounding cover 1 is adjusted while checking the angle position of the rotating shaft 110 from the outside.
A stopper 170 can be attached to 62. When the stopper 170 is mounted, if the positional relationship between the tip of the stopper 170b and the projection 113a can be confirmed, the entire upper surrounding cover 162 does not need to be transparent, and at least the mounting area of the stopper 170 is transparent. Should be fine.

The stepping motor 10 according to the present embodiment
0 is basically the same as that of the first embodiment described above, but when the disk rotor 120 rotates about 360 °, the projection 113a again comes into contact with the outer peripheral surface of the stopper 170b. Is not performed.

Therefore, if a pointer or the like for indicating desired information is attached to the other end 110a of the rotating shaft 110 of the stepping motor 100 according to the present embodiment, for example, a speedometer, a tachometer, a fuel gauge, a water temperature gauge of an automobile Etc. can be used as a drive source for driving the pointer.

FIG. 10 shows a third embodiment of the stepping motor according to the present invention. FIG. 10 (a) is a plan view in which some components (an upper surrounding cover 262 described later) are omitted.
(B) is a longitudinal sectional view. The stepping motor 200 according to this embodiment includes, as shown in FIG.
0 having a magnetic pole on both side surfaces extending in a direction perpendicular to the axis of the rotating shaft.
And a stator composed of a first stator group 230 and a second stator group 240 arranged at intervals in the circumferential direction of the disk rotor 220. Stator group 2
A pair of first plate-like yokes 231a, 23
1b and a pair of second plate-like yokes 241a, 241b, a flange member 212 for holding and fixing the disk rotor 220, an arrangement relation of the annular fixing member 213, a lower surrounding cover 261 constituting one of the surrounding covers 260, and further added. The second embodiment is the same as the first and second embodiments except that the stopper 170 is different from the first embodiment, and the description of the same parts will be omitted.

The stepping motor 20 according to the present embodiment
0, the flange member 212 similar to the first embodiment and the annular fixing member 21 similar to the second embodiment.
3 are mounted upside down.

The lower surrounding cover 261 constituting one of the surrounding covers 260 is formed entirely of a transparent resin material so that the inside can be visually recognized. A circular hole 261b having a counterbore is formed in a part of the wall surface, and a stopper 170 similar to that of the second embodiment is fitted into the circular hole 261b. ing.

As described above, since the lower surrounding cover 261 is formed of a transparent material, the stopper 17
In order to prevent the end of the lower stopper 170b from colliding with the protrusion 213a of the annular fixing member 213, the angle of the rotating shaft 210 is adjusted and the lower surrounding cover 2 is adjusted.
A stopper 170 can be attached to 61. When the stopper 170 is attached, if the positional relationship between the tip of the stopper 170b and the protrusion 213a can be confirmed, the entire lower surrounding cover 261 does not need to be transparent. What is necessary is just to be transparent.

Further, in the stepping motor 200 according to the present embodiment, a pair of first plate-like yokes 231 and a pair of second plate-like yokes 241 constituting the first stator group 230 and the second stator group 240, respectively, , Upper flat yoke 231a and lower flat yoke 2
31b, the upper plate-like yoke 241a and the lower plate-like yoke 241b are respectively provided with pole teeth 231a ', 231b' and 241a ', 241 sandwiching the disk rotor 220.
As compared with the separation distance in the region b ′, the first exciting coil 233
(Not shown) and the area where the second excitation coil 243 is arranged is set to have a large separation distance, that is, it is basically flat, but the pole teeth 231 a ′, 231 b ′ and 241 are formed.
It is formed so as to generate a step in the base region of a 'and 241b'.

The upper flat yoke 231a, 241a
And the lower flat yoke 231b, 241b
As in the case of the second embodiment, a plate made of a highly permeable material such as permalloy, silicon steel, or iron is formed by press molding or the like, and the whole is formed in a substantially arc shape, and its inner peripheral region is formed. , A plurality of substantially rectangular pole teeth 231 a ′ and 231 b ′ that extend in parallel to both surfaces (magnetic pole surfaces) 220 b and 220 c of the disk rotor 220 and taper toward the center of the rotation shaft 210. And pole teeth 241 a ′ and 241 b ′.

The pole teeth 231 a ′ and 231 b ′ and the pole teeth 241 a ′ and 241 b ′ have a center angle of less than 180 ° with respect to the rotation center of the rotation shaft 210.
They are formed at equal pitch intervals in the circumferential direction of the disk rotor 220. Also in the present embodiment, since the number of poles of the disk rotor 220 is 48, that is, 24 pitches, the pitch interval is set to be 15 ° and the central angle is set to 15 °, and the disk rotor 220 is formed 11 pieces each.

The upper plate-like yoke 241a and the lower plate-like yoke 231b are separated by a large distance between the upper plate-like yoke 231a and the lower plate-like yoke 231b.
a and iron plates 232 (not shown) and 242, which are taller than those of the first and second embodiments, and a bobbin which is also taller than those of the first and second embodiments. 234 (not shown) and 244 are arranged, and a first excitation coil 233 (not shown) wound around these bobbins 234 and 244 so as to be taller than those of the first and second embodiments. ) And the second excitation coil 24
3 are arranged.

The upper flat yoke 231a, 241a
A spacer (not shown) is arranged between the lower flat yoke 231b and the lower flat yoke 241b so that the two are held at a predetermined distance in an assembled state. This spacer is used. Instead, bobbins 234 and 244
Can also serve as a spacer.

First stator group 2 configured as described above
30 and the first stator group 240 include the magnetic pole surfaces 220b, 22
0c, the pole teeth 23
1 a ′, 231 b and pole teeth 241 a ′, 241 b ′ are arranged so as to sandwich the disk rotor 220, and the energized magnetic field of the first excitation coil 233 and the second excitation coil 243 is changed to the iron cores 232, 242 and the upper flat plate Yoke 231a,
241a and the lower flat yokes 231b, 241b form a magnetic path, and their pole teeth 231a ', 231b'.
And an excitation pole is generated at the pole teeth 241a 'and 241b'. For example, when the pole teeth 231a 'and 241a' are N poles,
1b 'and 241b' are at the S pole, and the pole teeth 231a 'and 241 are at the S pole.
When a 'is the south pole, the pole teeth 231b' and 241b 'are formed on the north pole.

Then, as described above, the pole teeth 231a ', 23
1b ′ and the excitation poles generated on the pole teeth 241a ′ and 241b ′ and the pole faces 220b and 220 of the disk rotor 220.
A magnetic attractive force and a repulsive force are generated between the magnetic pole formed at the point c and the magnetic pole formed at the point c.

The stepping motor 20 according to the present embodiment
The operation of 0 is basically the same as that of the first embodiment described above. However, when the disk rotor 220 rotates about 360 °, the protrusion 213a comes into contact with the outer peripheral surface of the stopper 170b again. Is not performed.

Therefore, similarly to the second embodiment,
The other end 21 of the rotating shaft 210 of the stepping motor 200
If a pointer or the like indicating desired information is attached to the 0a side,
For example, it can be used as a drive source for driving a pointer such as a speedometer, a tachometer, a fuel gauge, and a water temperature gauge of a car.

The upper plate-like yokes 231a and 231a constituting the first stator group 230 and the second stator group 240
The number of turns of the first excitation coil 233 and the second excitation coil 243 can be increased by an amount corresponding to a large separation distance between the first excitation coil 233 and the second excitation coil 243, while the pole teeth 231 a ′ and 231 b sandwiching the disk rotor 220. , And the pole teeth 241 a ′ and 241 b ′ are maintained at a predetermined interval.
An excitation pole is efficiently generated by the third and second excitation coils 243, and the pole teeth 231a 'and 231 used as the excitation pole are formed.
Magnetic attractive force or repulsive force is efficiently generated between b ′ and the pole teeth 241 a ′ and 241 b ′ and the magnetic pole surfaces 220 b and 220 c of the disk rotor 220.

FIG. 11 is a plan view showing a fourth embodiment of the stepping motor according to the present invention. As shown in FIG. 11, a stepping motor 300 according to this embodiment includes a flat disk rotor 320 having magnetic poles on both sides fixed to a rotating shaft 310 and extending in a direction perpendicular to the axis of the rotating shaft. A stator including a first stator group 330 and a second stator group 340 arranged at an interval in the circumferential direction of the rotor 320 is provided as a basic configuration thereof, which is different from the first to third embodiments. A pair of first flat yokes 331 (upper flat yoke 331a, lower flat yoke 331b (not shown)) and a pair of second flat yokes constituting the first stator group 330 and the second stator group 340. 341 (upper plate-like yoke 341a, lower plate-like yoke 341b (not shown)) are provided with a plurality of excitation coils. Outside is identical to the above first to third embodiments, description of the same portions will be omitted.

The stepping motor 30 according to the present embodiment
At 0, as shown in FIG. 11, the upper plate-shaped yoke 331a, the lower plate-shaped yoke 331b, the upper plate-shaped yoke 341a, and the lower plate-shaped yoke 341a having a substantially arc shape are formed.
b, two iron cores 332 and 342 are arranged, respectively, and two first excitation coils 333 and second excitation coils 343 are respectively arranged via bobbins (not shown).

According to the stepping motor 300 of this embodiment, since the plurality of first excitation coils 333 and the second excitation coils 343 are provided as described above, the pole teeth 331a 'and 331b' ( (Not shown) and pole teeth 34
Excitation poles can be efficiently generated for 1a 'and 341b' (not shown).

[0078]

As described above, according to the stepping motor of the present invention, the rotor is formed as a plate-shaped disk rotor having magnetic poles formed on both sides having a surface extending in a direction perpendicular to the axis of the rotating shaft. Since the first stator group and the second stator group are formed and the stator is formed by the first stator group and the second stator group arranged at intervals in the circumferential direction of the disk rotor, the first stator group and the second stator group are formed by the axis of the rotating shaft. Compared to a conventional stepping motor that is stacked in the direction, the thickness of the rotating shaft can be reduced in the axial direction, that is, in the thickness direction, and as a result, the overall size can be reduced. Further, since the first stator group and the second stator group are arranged to face each other with the disk rotor interposed therebetween, it is possible to reduce magnetic leakage between the two. Furthermore, since the pole teeth are formed without being bent so as to extend in parallel to both surfaces of the disk rotor, variations in the pitch distance between the pole teeth can be prevented. High accuracy of position can be achieved

In the stepping motor having the above configuration, a case where a plurality of the first exciting coils and the second exciting coils are provided between the pair of the first plate-shaped yokes and the pair of the second plate-shaped yokes, respectively. Can efficiently generate excitation poles for the pole teeth formed on the pair of first flat yoke and the pair of second flat yoke, respectively.

In the stepping motor having the above configuration, the pair of first plate-like yokes and the pair of second plate-like yokes are each compared with the first excitation coil and the pair of second plate-like yokes with respect to the separation distance of the pole teeth region sandwiching the disk rotor. In the case where the separation distance of the region where the second excitation coil is disposed is increased, the number of turns of the first excitation coil and the second excitation coil can be increased by the distance, and on the other hand, the disk Since a predetermined interval is maintained in the portion of the pole teeth sandwiching the rotor, the first excitation coil and the second excitation coil can efficiently generate the excitation pole, and the pole used as the excitation pole Magnetic attraction or repulsion can be efficiently generated between the teeth and the magnetic poles of the disk rotor.

In the stepping motor having the above structure, when the disk rotor is formed by using a powder magnet and a resin material, the disk rotor itself is lightweight, so that its moment of inertia can be reduced, and The rotation response of the rotor itself can be improved.

In the stepping motor having the above configuration, when the pole teeth are formed in a substantially rectangular shape, it is possible to efficiently generate magnetic attraction or repulsion between the pole teeth of the disk rotor. it can.

When a stopper for stopping the disk rotor at a predetermined rotation angle position is provided in the stepping motor having the above structure, a pointer or the like for indicating desired information is attached to the rotation shaft of the stepping motor. For example, car speedometer, tachometer,
It can be used as a drive source for driving a pointer such as a fuel gauge or a water temperature gauge.

In the stepping motor having the above structure, when at least a portion of the surrounding cover surrounding the disk rotor and the stator for attaching the stopper is transparent, the surrounding cover is assembled so as to surround the disk rotor and the stator. Thereafter, when the stopper is inserted and attached at a desired position, the inside can be visually recognized through the transparent portion, so that the stopper can be easily attached.

[Brief description of the drawings]

1A and 1B show a first embodiment of a stepping motor according to the present invention, wherein FIG. 1A is a plan view and FIG. 1B is a longitudinal sectional view.

FIG. 2 is an external perspective view showing a disk rotor constituting a part of the stepping motor according to the present invention.

FIG. 3 is a diagram showing a drive voltage waveform when driving a stepping motor according to the present invention.

FIGS. 4A to 4E are diagrams for schematically explaining the driving of the stepping motor according to the present invention, and FIGS. 4A to 4E are state diagrams at respective driving positions.

FIG. 5 is a diagram showing another driving voltage waveform when driving the stepping motor according to the present invention.

FIG. 6 is a diagram showing another driving voltage waveform when driving the stepping motor according to the present invention.

FIGS. 7A to 7E are diagrams for schematically explaining the driving of the stepping motor according to the present invention, and FIGS. 7A to 7E are state diagrams at respective driving positions.

FIG. 8 is a diagram showing another driving voltage waveform when driving the stepping motor according to the present invention.

FIGS. 9A and 9B show a second embodiment of the stepping motor according to the present invention, wherein FIG. 9A is a plan view and FIG. 9B is a longitudinal sectional view.

FIGS. 10A and 10B show a third embodiment of the stepping motor according to the present invention, wherein FIG. 10A is a plan view thereof and FIG.
Is a longitudinal sectional view thereof.

FIG. 11 is a plan view showing a fourth embodiment of the stepping motor according to the present invention.

FIG. 12 is a schematic configuration diagram showing a conventional stepping motor.

[Explanation of symbols]

 Reference Signs List 10 stepping motor 11 rotation shaft 12 flange member 13 annular fixing member 20 disk rotor 20b, 20c magnetic pole surface 30 first stator group 31 pair of first flat yoke 31a upper flat yoke 31a 'pole teeth 31b lower flat yoke 31b 'Pole teeth 32 Iron core 33 First excitation coil 40 Second stator group 41 A pair of second flat yoke 41a Upper flat yoke 41a' Polar teeth 41b Lower flat yoke 41b 'Polar teeth 42 Iron core 43 Second excitation Coil 100 Stepping motor 110 Rotating shaft 113 Annular fixing member 113a Projection 120 Disk rotor 130 First stator group 140 Second stator group 161 Lower surrounding cover 162 Upper surrounding cover 170 Stopper 200 Stepping motor 210 Rotating shaft 220 Disk rotor 230 First stator group 231a Upper flat yoke 231a 'Polar teeth 231b Lower flat yoke 231b' Polar teeth 233 First excitation coil 240 Second stator group 241a Upper flat yoke 241a 'Polar teeth 241b Lower flat yoke 241b' Polar teeth 243 Second excitation coil 261 Lower surrounding cover 262 Upper surrounding cover 300 Stepping motor 310 Rotating shaft 320 Disk rotor 330 First stator group 333 First excitation coil 340 Second stator group 343 Second excitation coil

Claims (7)

[Claims] A rotor fixed to a rotating shaft and having a magnetic pole; a stator having an exciting coil and a yoke for guiding a magnetic field of the exciting coil; the exciting pole formed on the pole teeth of the yoke and the rotor; A stepping motor for rotating the rotor by a predetermined angle by magnetic attraction and repulsive force with the magnetic poles of the magnetic poles, wherein the rotor has magnetic poles formed on both sides having a surface extending in a direction perpendicular to the axis of the rotation shaft. Wherein the stator comprises a first stator group and a second stator group arranged at intervals in a circumferential direction of the disk rotor, and wherein the first stator group comprises the disk The disk rotor is disposed so as to sandwich the rotor, extends in parallel to both surfaces of the disk rotor, and extends toward the center of the rotation shaft. A pair of first plate-shaped yokes each having a plurality of pole teeth formed at equal pitch intervals in the circumferential direction of the scroller, and a first excitation coil for forming a magnetic field in the pair of first plate-shaped yokes; The second stator group is disposed so as to sandwich the disk rotor, extends in parallel to both sides of the disk rotor, and extends toward the center of the rotation shaft, and extends in the circumferential direction of the disk rotor. A stepping motor, comprising: a pair of second flat yokes each having a plurality of pole teeth formed at a pitch interval; and a second exciting coil for forming a magnetic field on the pair of second flat yokes. . 2. A plurality of first and second excitation coils are provided between the pair of first plate-shaped yokes and the pair of second plate-shaped yokes, respectively. The stepping motor according to claim 1, wherein 3. The first excitation coil and the second excitation coil each of the pair of first plate-like yokes and the pair of second plate-like yokes have a separation distance of a pole tooth region sandwiching the disk rotor. 3. The stepping motor according to claim 1, wherein the stepping motor is formed such that a separation distance of a region where the step is arranged is increased. 4. The stepping motor according to claim 1, wherein the disk rotor is formed using a powder magnet and a resin material. 5. The stepping motor according to claim 1, wherein the pole teeth are formed in a substantially rectangular shape. 6. The stepping motor according to claim 1, further comprising a stopper for stopping the disk rotor at a predetermined rotation angle position. 7. The stepping motor according to claim 6, further comprising a surrounding cover surrounding the disk rotor and the stator, wherein the surrounding cover has at least a transparent area for attaching the stopper.