JP4216369B2 - Stepping motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a stepping motor and, for example, to a stepping motor used for positioning by feeding an access head such as a flexible disk device or an optical disk drive device or driving a mechanical component such as a camera.
[0002]
[Prior art]
The conventional PM stepping motor has a structure shown in FIG. That is, the rotating shaft 115 is rotated by using a permanent magnet for the rotor 110. A yoke (Yoke) 120 constituting a magnetic circuit having a predetermined (certain) gap (Gap) is arranged outside the circumference, and a magnetic field is generated circumferentially by electric power on the outer circumference. A structure in which the coil part 130 was disposed was provided.
[0003]
Therefore, the size of the motor is the size (thickness) indicated by “D” in FIG. 4 in which the diameter of the rotor 110 “d” is added to the thickness of the yoke portion and the coil.
[0004]
[Problems to be solved by the invention]
However, downsizing and thinning of the conventional PM type stepping motor having the structure shown in FIG. 4 has been achieved by reducing all the components on a concentric circle.
[0005]
However, if the shape of the motor is scaled down as it is, the diameter of the permanent magnets magnetized in the multipoles of the rotor part that generates rotational torque also becomes small. As a result, the rotational torque obtained as the diameter of the motor becomes smaller has also become smaller.
[0006]
In addition, in the conventional motor structure of this type, since the coil is wound around the concentric circle of the rotating shaft, the space for winding the coil is reduced, so that the coil that is a constant torque of the motor is generated. The ampere turn (AT: current flowing in the coil × number of coil turns), which is a magnetic force, is also reduced, and the generated rotational torque is also reduced as the diameter of the motor is reduced.
[0007]
[Means for Solving the Problems]
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an easy-to-use small stepping motor that does not decrease the generated rotational torque even if it is reduced in size and thickness. For example, the following configuration is provided as one means for achieving the object.
[0008]
That is, a rotor formed of permanent magnets are arranged in the axial direction of said rotor, said rotor and concentric cylindrical pair of yokes, extending portion extending in the outer circumferential direction from the outer surface of one of the yoke A first L-shaped first extending portion that is bent from the extending portion to the other yoke side and extends substantially parallel to the axial direction, and an outer periphery from the outer surface of the other yoke. direction, which has the extended portion and the extending portion extending approximately equal amounts of the first extending portion, extending parallel said axis substantially by bending from the extended portion to one of the yoke-side a second extending portion of the substantially L-shaped having a portion, have a said first and coil wound around said axis and a portion extending substantially parallel to the second extending portion, the first and second 2 The portion of the extending portion extending substantially parallel to the axial direction is the extending direction and the extending portion. Is wider in the orthogonal direction orthogonal to the extending direction, the coil, characterized in that it forms a wide long cylindrical in the perpendicular direction.
[0009]
And for example, wherein the first and second extending portions are Na a substantially L-shape bent by a plate-like.
[0010]
Further, for example, the width in the direction perpendicular to the extending direction of the extending portion and perpendicular to the axial direction is shorter than the diameter of the rotor.
[0011]
Embodiments of the present invention will be described below with reference to the drawings.
[0012]
[First Embodiment]
An embodiment of an invention according to the present invention will be described in detail. FIG. 1 is a diagram for explaining the configuration of a stepping motor according to this embodiment, and FIG. 2 is a diagram for explaining an example of the detailed structure of the A-phase yoke and coil according to this embodiment.
[0013]
1 and 2, 10 is a rotor formed of a permanent magnet, 15 is a rotating shaft, 20 is a magnet with a predetermined (certain) gap (Gap) disposed on the outer circumference of the rotor 10. A yoke constituting the circuit, 30 is a coil wound around the coil winding portion 25, and 40 is a motor cover.
[0014]
The yoke 20 includes an A-phase yoke 21 shown on the lower side of FIG. 1, a B-phase yoke 23 shown on the upper side, and magnetic pole teeth positioned between the magnetic pole teeth of these yokes. A pair of yokes 22, 24 including coil holding portions 26, 28 for holding the coil is disposed between the phase yoke 23 and a coil winding portion 25, which will be described later.
[0015]
As shown in FIG. 2, there is provided a coil winding portion 25 having a substantially L-shaped cross section that extends in the outer peripheral direction from one side surface of the A-phase yoke 22 and is magnetically coupled to the yoke. A coil holding part 26 having a substantially L-shaped cross section is provided which extends in the outer peripheral direction from one side surface of the paired yoke 22 and is magnetically coupled to the yoke.
[0016]
Then, by winding the coil 30 around the coil winding part 25 and holding it by the coil holding part 26, the coil that has been conventionally arranged on the concentric circumference of the rotating shaft can be shifted in the lateral direction. In addition, a magnetic field can be generated in the yoke that constitutes the magnetic circuit by winding a coil around a portion extending “L” from the yoke.
[0017]
As a result, the total thickness of the motor can be suppressed to “H”, which is the sum of the thickness of the yoke portion and the thickness of the motor case, compared to the diameter “d” of the rotor 10.
[0018]
As described above, according to the present embodiment, a coil is wound around a portion extending “L-shaped” from a yoke concentric with a rotating shaft (rotor magnet) using a permanent magnet. Thus, it is possible to wind a coil that has conventionally been on the concentric circumference of the rotating shaft while shifting it in the lateral direction, and by applying electric power to this coil, a magnetic field can be generated in the yoke.
[0019]
In addition, when the diameter of the rotor magnet associated with the rotating shaft is “d”, the coil of the present embodiment is larger than the size of the magnetic circuit and the coil portion surrounding the magnetic circuit in the conventional shape. In the case of a motor having a structure in which the portion is moved to the side, it becomes a flat type, but the outer diameter shape of the motor can be reduced. This makes it possible to reduce the thickness of the motor without reducing the diameter of the rotor magnet using the permanent magnet on the rotating shaft.
[0020]
[Second Embodiment]
In the above description, the coil is wound wide in the circumferential direction as shown in FIG. 1, but the present invention is not limited to the above winding direction, and two sets for A phase and B phase are used. However, in a case where the thickness is a problem, it may be wound vertically in the circumferential direction instead of being widened in the circumferential direction.
[0021]
FIG. 3 shows an embodiment of the second invention according to the present invention which is wound vertically in the circumferential direction. As shown in FIG. 3, in the second embodiment, the coil is wound vertically in the circumferential direction. Other basic configurations are the same as those of the first embodiment described above. However, if the coil is configured to be vertically long, the structure of the coil winding portion may be a shape that matches the structure of the coil.
[0022]
As described above, according to the embodiment of the second invention, since the coil is wound vertically in the circumferential direction, the thickness of the motor can be reduced even if the coil is wound many times. The size and thickness can be reduced without reducing the motor torque.
[0023]
[Other Embodiments]
In the first and second embodiments described above, a motor having a shape in which a coil is wound only in one direction has been described. However, the present invention is not limited to the above examples. Coil winding portions may also be provided in the opposite direction, and the coils may be wound individually and formed in two opposing directions. Furthermore, of course, depending on the structure, coils may be formed in a plurality of directions.
[0024]
As described above, according to each embodiment, a flat PM-type stepping motor can be configured by forming the coil in the lateral direction of the rotating shaft. In addition, by using a thin stepping motor structure without reducing the diameter of the rotor magnet, it is possible to avoid the torque reduction associated with the reduction in diameter, and the disadvantage of multipolar magnetization due to the reduction in diameter of the rotor magnet. Can be improved.
【The invention's effect】
According to the present invention described above, traditional may be winding shifted there to the rotating shaft concentric circle on the coil in the transverse direction, the diameter of the rotor magnet using a permanent magnet in the rotation axis The motor can be reduced in thickness without reducing the size. As a result, it is possible to achieve a thin motor structure without reducing the diameter of the rotor, and it is possible to avoid the torque reduction associated with the reduction in diameter, and the disadvantage of multipolar magnetization due to the reduction in diameter of the rotor. Can be improved.
[0025]
[Brief description of the drawings]
FIG. 1 is a diagram for explaining a configuration of a stepping motor according to an embodiment of the present invention.
FIG. 2 is a diagram for explaining an example of a detailed structure of an A-phase yoke and coil according to the present embodiment.
FIG. 3 is a diagram showing a configuration of a stepping motor according to an embodiment of the second invention according to the present invention.
FIG. 4 is a view for explaining the structure of a conventional PM type stepping motor.
[Explanation of symbols]
10, 110 Rotor 15, 115 formed of permanent magnets Rotating shafts 2022, 24, 120 Yoke 21 A-phase yoke 23 B-phase yoke 30, 130 Coil 40 Motor cover 25 Coil winding portion 26, 28 Coil holding portion

Claims (3)

A rotor formed of permanent magnets;
A pair of yokes arranged side by side in the axial direction of the rotor, concentric with the rotor;
A substantially L-shape having an extending portion extending in the outer peripheral direction from the outer surface of one of the yokes, and a portion extending from the extending portion to the other yoke side and extending substantially parallel to the axial direction. The first extension of
In the outer peripheral direction from the outer surface of the other of said yoke, which has the extended portion and the extending portion extending approximately equal amounts of the first extending portion, bent from the extending portion to one of the yoke-side A substantially L-shaped second extending portion having a portion extending substantially parallel to the axial direction;
Possess a coil wound around said first and said axis and a portion extending substantially parallel to the second extending portion,
The portions of the first and second extending portions extending substantially parallel to the axial direction are wide in the extending direction and the orthogonal direction orthogonal to the extending direction of the extending portion,
The stepping motor according to claim 1, wherein the coil has a long and long cylindrical shape in the orthogonal direction . Stepping motor according to claim 1, wherein said first and second extending portion has a substantially L-shape bent by a plate-like. The stepping motor according to claim 1, wherein a width of the extending portion in a direction orthogonal to the extending direction and orthogonal to the axial direction is shorter than the diameter of the rotor.

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