JPH04178155A - Motor - Google Patents

Abstract

PURPOSE:To surely avoid the interference between a stator iron core and a magnetic head and rotate the rotor smoothly by making a recess from the outer peripheral face side of the required part of the iron core of the stator, which is positioned outside the rotor rotating integrally with the rotary shaft, toward the side of the inner peripheral face. CONSTITUTION:This is equipped with a rotor, which rotates integrally with the rotary shaft 21 and on the outer periphery of which a ring-shaped driving magnet 25 to generate a magnetic field in the radial direction is arranged, a stator, which is positioned outside the rotor and on the iron cores 31 of which a plurality of coils 32 are wound, and a recessed part 34, which is made by recessing the outer peripheral face of the specified part of the iron core 31 of the stator toward the inner peripheral face side, and making the inner peripheral face side the connection 35 being connected with the iron core 31 of the stator, and making the connecting face 35a on rotor side of the connection 35 the circular arc in accord with the external form of the driving magnet 25. Accordingly, the magnetic head can move inside the recessed part 34 without interfering with the iron core 31 of the stator.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electric motor, and in particular to a recording device used in a device having a magnetic head for reading and writing magnetic recording signals on a magnetic disk, which is a disc-shaped recording medium. The present invention relates to an electric motor for driving rotation of a medium.

[Prior art] As a conventional electric motor of this type, Utility Model Application No. 60-13586
The technology published in Publication No. 3 can be mentioned.

FIG. 5 is a sectional view showing a conventional electric motor.

In the figure, (1) is the rotating shaft of the electric motor, (2) is a rotating body that has a magnetic disk holding function;
) rotates integrally with the rotating shaft (1). (3) is the rotor of the electric motor, (4) is the yoke of the rotor (3), (
5) is a permanent magnet arranged on the outer periphery of the yoke (4), (
6) is the screw fixing the rotor (3) and the rotating shaft (1), (7) is the stator of the motor, and (8) is the stator (
7) is the iron core, (9) is the coil wound around the iron core (8),
(10) is a bearing mounting member, and (11) and (12) are bearings that are mounted on the bearing mounting member (11) and rotatably support the rotating shaft (1). (13) is the frame of the electric motor, (
14) is a screw fixing the stator (7) and the bearing mounting member (10), and (15) is a drive pin attached to the rotating body (2), and this drive pin (15) is a screw that fixes the stator (7) and the bearing mounting member (10). It engages with a window hole (not shown) in a rotary plate fixed to the rotary plate.

(16) is an index detection element disposed on the frame (13), (17) is an index detection magnet disposed on the rotor (3), and this index detection element (
16) and the index detection magnet (17) generate one pulse per rotation.

The electric motor with the above configuration has a rotor (3) on the outside of the stator (7).
The permanent magnet (5) of the rotor (3) generates a magnetic field in the radial direction of rotation. In this electric motor, a coil (
By controlling the energization to the rotor (3), the rotor (3)
) is rotationally driven. The rotation of the rotor (3) drives a magnetic disk (not shown) to rotate as appropriate.

[Problems to be Solved by the Invention] The conventional outer rotor type electric motor as described above requires a certain amount of space between the rotor (3) and the stator (7). Further, a frame (13) or a bearing mounting member (10) was interposed between the stator (7) and rotor (3) and the magnetic disk and magnetic head. Therefore, there is a limit to how thin the electric motor can be made. For this reason, it has been considered to create a thin inner rotor type electric motor in which the stator (7) is located outside the rotor (3).

However, even in this type of electric motor, there is a risk of interference between the stator core and the magnetic head, so a certain gap is required on the magnetic disk side of the stator to avoid interference with the magnetic head. It was. For this reason, it has not been possible to reduce the overall thickness of the electric motor very much.

Also, in order to avoid interference with the magnetic head, it was considered to cut the stator core and provide a notch, but simply cutting the stator core would not allow the drive to be cut off and the general part. The magnetic field acting between the rotor and the rotor magnet (25) became extremely non-uniform, impeding smooth rotation of the rotor and shortening the life of the rotating shaft and bearing.

Therefore, the object of this invention is to provide a thin electric motor that can reliably avoid interference between the stator core of the stator and the magnetic head, and in which the rotor rotates smoothly. .

[Means for Solving the Problems] An electric motor according to the present invention rotates with a rotatably supported rotary shaft (21) and the rotary shaft (21), and generates a magnetic field in the rotation radius direction on the outer circumference. A rotor is provided with a ring-shaped drive magnet (25) that generates a
32), and the stator core (31).
A concave portion is formed from the outer peripheral surface side to the inner peripheral surface side of a predetermined portion of the
A concave portion (34) whose inner peripheral surface side is connected by a stator core (31) and whose rotor side connecting surface (35a) is formed as a concentric arc according to the outer shape of the driving magnet (25).
).

[Function] In the present invention, a recess is formed in a predetermined portion of the stator core (31) of the stator located outside the rotor that rotates integrally with the rotating shaft (21) from the outer peripheral surface side toward the inner peripheral surface side. A concave portion (34) is formed in which the inner peripheral surface side is connected by the stator core (31) and the rotor side connecting surface (35a) is a concentric arc corresponding to the outer shape of the driving magnet (25). The magnetic head can move within the concave portion (34) without interfering with the stator core (31), and the stator is designed to avoid interference between the stator and the magnetic head. In addition to eliminating the gap on the magnetic disk side, the stator core (31) and rotor drive magnet (2
5) becomes uniform, and the magnetic field acting therebetween becomes uniform.

[Example] Examples of the present invention will be described below.

<First Embodiment> FIG. 1 is a sectional view showing an electric motor according to a first embodiment of the present invention, and FIG. 2 is a plan view showing the electric motor of FIG. 1.

In the figure, (21) is a rotating shaft of an electric motor, and (22) is a rotating body having a magnetic disk holding function, and this rotating body (22) rotates integrally with the rotating shaft (21). (2
3) is a disk mounting surface formed on the rotating body (22), (
24) is a rotor yoke embedded in the rotating body (22), (
25) is a driving magnet consisting of a permanent magnet arranged on the outer periphery of the rotor yoke (24), and (26) is a rotating body (
This drive pin is attached to the drive pin (22).
6) engages with a window hole (not shown) in a rotary plate fixed to the magnetic disk. (31) is a stator core, and (32) is a coil wound around the stator core (31). This stator core (31) and coil (32) constitute a stator of the electric motor.

(34) is a concave portion formed from the outer peripheral surface of the stator core (31) toward the inner peripheral surface, and (35) is this concave portion (
34), the inner circumferential surface of which is connected to the stator core (31). Note that the rotor side connecting surface (35a) of this connecting portion (35) has a shape that corresponds to the outer shape of the rotor.

(40) is a frame that also serves as a circuit board, (41) is a bearing mounting member attached to the frame (40), (42) is a sintered oil-impregnated bearing that rotatably supports the rotating shaft (21), (
43) is a sliding member with a low friction coefficient interposed between the rotating body (22) and the sintered oil-impregnated bearing (42).

(44) is a screw that fixes the stator core (31) to the frame (40), and (45) is a spacer interposed between the stator core (31) and the frame (40).

The electric motor of this embodiment is constructed as described above, and the stator core (31) is capable of passing magnetic flux in the direction of the rotation radius of the electric motor. Iron core teeth are formed at 15 angles, and 15 coils (32) are wound around the iron core teeth. Then, a concave portion (34
), and the inner peripheral surface side is connected with an iron core to form a connecting part (35). This concave portion (34) allows the magnetic head to move without interfering with the stator.

Further, the rotor driving magnet (25) located on the inner circumferential side of the stator has, for example, 24 equally divided N and S poles magnetized in the rotation radius direction of the rotor. The 15 coils (32) of the stator are wound every second in three phases, and are energized 120 degrees in accordance with the rotation angle of the rotor, causing rotational torque loss in a certain direction.

As described above, the electric motor of this embodiment is an inner rotor type in which the stator is located outside the rotor, and the stator is formed with a concave portion (34) for moving the magnetic head.
Unlike the conventional outer rotor type electric motor, the gap for avoiding interference between the stator and rotor and the magnetic disk and magnetic head can be omitted, so the thickness of the entire electric motor can be reduced.

Furthermore, in this embodiment, the inner circumferential side of the concave portion (34) formed from the outer circumferential surface of the stator core (31) toward the inner circumferential side is connected by the stator core (31), and the connecting portion (35) It becomes. Further, the rotor-side connecting surface (35a) of this connecting portion (35) is connected to the drive magnet (2) on the outer circumference of the rotor.
5) It is a concentric arc according to the external shape. Therefore, the gap between the connecting portion (35) of the concave portion (34) and the driving magnet (25) becomes uniform, and the magnetic field acting therebetween is made uniform. Therefore, compared to the case where the stator core (31) is simply cut and notched to avoid interference with the magnetic head, an uneven magnetic field does not act on the rotor, so the rotor rotates smoothly. , rotating shaft (21)
And the life of the sintered oil-impregnated bearing (42) is also extended.

As mentioned above, the electric motor of this example has a sintered oil-impregnated bearing (
a rotating shaft (21) rotatably supported by 42);
It rotates integrally with this rotating shaft (21), and the outer circumference has a half-rotation
A ring-shaped driving magnet (
25), a stator located outside the rotor and having a plurality of coils (32) wound around the stator core (31), and Predetermined part (
A concave portion is formed from the outer peripheral surface side of the movable portion of the magnetic head toward the inner peripheral surface side, and the inner peripheral surface side is connected by a stator core (31) to form a connecting portion (35). The rotor side connecting surface (35a) is connected to the drive magnet (25).
) is formed as a concentric arc according to the outer shape of ( ).
34).

That is, the electric motor of this embodiment has a stator core (3
1) A recess is formed from the outer peripheral surface of the movable portion of the magnetic head toward the inner peripheral surface, and this inner peripheral surface is connected to the stator core (31
) to form a concave portion (34), and the rotor side connecting surface (35a) of the connecting portion (35) of this concave portion (34) is connected to the driving magnet (25). They are concentric arcs that correspond to the external shape of.

Therefore, the magnetic head can move within the concave portion (34) without interfering with the stator core (31),
Since the gap on the magnetic disk side of the stator to avoid interference between the stator and the magnetic head as in the conventional case can be omitted, the thickness of the entire motor can be reduced. Moreover, the gap between the connecting part (35) of the concave part (34) and the driving magnet (25) becomes uniform, and the magnetic field acting between them becomes uniform, so that the rotor rotates smoothly.
The life of the rotating shaft (21) and the sintered oil-impregnated bearing (42) is also extended.

As a result, it is possible to promote reduction in the thickness of the entire electric motor, smoother rotation of the rotor, and longer life of the rotating shaft and bearing.

<Second Embodiment> FIG. 3 is a plan view showing an electric motor according to a second embodiment of the present invention. In the drawings, the same reference numerals and symbols as those in the first embodiment indicate constituent parts that are the same as or correspond to those in the first embodiment.

In the figure, (35b) is the connecting part (
35), and this counter-rotor side connecting surface (35b) is a concentric arc according to the outer shape of the driving magnet (25) on the outer periphery of the rotor.

That is, the counter-rotor side connecting surface (35b) is also a concentric arc with the rotor side connecting surface (35a). The other configurations are the same as those of the above embodiment.

Therefore, the electric motor of this embodiment is also an inner rotor type in which the stator is located outside the rotor, and the stator is formed with a concave portion (34) for moving the magnetic head.
Unlike the conventional outer rotor type electric motor, the gap between the stator and rotor and the magnetic disk and magnetic head to avoid interference can be omitted, so the thickness of the entire electric motor can be reduced.

Moreover, in this example as well, as in the above example,
The inner circumferential side of the concave portion (34) formed from the outer circumferential surface of the stator core (31) toward the inner circumferential side is the stator core (31).
) to form a connecting part (35). In addition, the rotor side connecting surface (35a) and the counter-rotor side connecting surface (35b) of the connecting portion (35) in this embodiment are connected to the driving magnet (2).
It is a concentric arc according to the external shape of the connecting part (3).
5) has a uniform width dimension. Therefore, in this embodiment as well, the gap between the connecting portion (35) of the concave portion (34) and the driving magnet (25) is uniform;
The magnetic field acting during this time is made uniform, and in particular, since the connecting portion (35) has a uniform width dimension, the magnetic field acting on the rotor is made more uniform compared to the above embodiment, and the rotor Rotation becomes smoother.

As described above, the electric motor of this embodiment includes a rotating shaft (21), a rotor, and a stator similar to those of the above embodiment, and the movable portion of the magnetic head of the stator core (31). A concave portion is formed from the outer circumferential surface side toward the inner circumferential surface side, and this inner circumferential surface side is connected by a stator core (31) to form a predetermined concave portion (3
4) is formed, and in addition, the rotor side connecting surface (35a) and the counter-rotor side connecting surface (35b) of the connecting portion (35) of this concave portion (34) match the outer shape of the driving magnet (25). They are concentric arcs.

Therefore, similarly to the above embodiment, the magnetic head can move within the concave portion (34) without interfering with the stator core (31), and the thickness of the entire motor can be reduced. Connecting portion (35) of shaped portion (34)
Since the magnetic field acting between the rotor and the drive magnet (25) is made more uniform, the rotor rotates more smoothly. Therefore, it is possible to promote reduction in the thickness of the entire electric motor, and to further promote smooth rotation of the rotor and extension of the life of the rotating shaft and bearing.

<Third Embodiment> FIG. 4 is a plan view showing an electric motor according to a third embodiment of the present invention. In the drawings, the same reference numerals and symbols as those in the first and second embodiments indicate constituent parts that are the same as or correspond to those in the first and second embodiments.

In the figure, (37) is the center line connecting the center of the rotating shaft (21) and the center of the concave part (34), and (38) is the center line connecting the general part of the stator core (31) and the concave part (34). Connecting part (35
).

(38a) is the core tooth side root surface located on the core tooth side of the root portion (38), and (38b) is the mouth shape side root surface located on the concave portion (34) side of the root portion (38). be. Further, in this embodiment, the width of the root portion (38) is wider than the width of the connecting portion (35). The other configurations are the same as those of the above embodiments.

Therefore, the electric motor of this embodiment is also an inner rotor type in which the stator is located outside the rotor, and the stator is formed with a concave portion (34) for moving the magnetic head, unlike the conventional outer motor. Unlike a rotor-type electric motor, it is possible to eliminate gaps to avoid interference between the stator and rotor and the magnetic disk and magnetic head, so the thickness of the entire electric motor can be reduced.

Moreover, in this embodiment as well, similarly to each of the above-mentioned embodiments, the inner circumferential surface side of the concave portion (34) formed from the outer circumferential surface portion of the stator core (31) toward the inner circumferential surface side is (3
1) to form a connecting portion (35). In addition, the rotor side connecting surface (35a) of the connecting portion (35) in this embodiment
are concentric arcs corresponding to the outer shape of the driving magnet (25). In addition, the base (38) of the connecting portion (35)
is wider than the connecting part (35), and furthermore, the root part (38) is wider at the connecting part with the general part of the stator core (31) than the connecting part with the connecting part (35). It becomes. As for the specific shape, the angle θ2 formed by the core tooth side root surface (38a) with respect to the center line (37) connecting the center of the rotating shaft (21) and the center of the concave portion (34) is on the mouth shape side. It is larger than the angle θ1 formed by the root surface (38b) (
θ2〉θ■). Therefore, the gap between the connecting part (35) of this concave part (34) and the driving magnet (25) becomes uniform, and the magnetic field acting between them becomes uniform, so that the rotor rotates smoothly. At the same time, the connecting part (3
Since the root portion (38) of 5) is wider than the connecting portion (35), the rigidity of the entire stator core (31) increases.

As described above, the electric motor of this embodiment includes a rotating shaft (21), a rotor, and a stator similar to those of the above embodiments, and the magnetic head of the stator core (31) can be moved. A recess is formed from the outer peripheral surface of the part toward the inner peripheral surface, and this inner peripheral surface is connected by the stator core (31) to form a recessed portion (34) of a predetermined shape. The rotor side connecting surface (35a) and the counter-rotor side connecting surface (35b) of the connecting portion (35) of the portion (34) are concentric arcs according to the outer shape of the drive magnet (25), and in addition, , connecting part (3
The base portion (38) of 5) is wider than the connecting portion (35).

Therefore, as in the above embodiment, the thickness of the entire electric motor can be reduced, the rotor rotates smoothly, and the base (38) of the connecting portion (35) is connected to the connecting portion (35).
Since the stator core (31) is wider than the stator core (31), the strength of the stator core (31) is improved. That is, it is possible to reduce the thickness of the entire electric motor, to make the rotation of the rotor smoother, to extend the life of the rotating shaft and bearings, and to improve the strength of the stator core (31).

[Effects of the Invention] As described above, the electric motor of the present invention includes a rotor that rotates integrally with a rotating shaft that is rotatably supported, and a stator located outside the rotor. A predetermined portion of the stator core has a concave portion extending from the outer circumference side toward the inner circumference side, and this inner circumference side is connected by the stator core, and the rotor side connecting surface is formed into a concentric arc according to the outer shape of the drive magnet. Due to the simple structure in which a concave portion is formed, the magnetic head can move within the concave portion without interfering with the stator core. Since the gap on the magnetic disk side can be omitted, the thickness of the entire motor can be reduced, and the gap between the stator core and the rotor drive magnet becomes uniform, which reduces the magnetic field that acts between them. Since the rotation is made uniform, the rotation of the rotor becomes smooth, and the life of the rotating shaft and bearings is extended.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an electric motor according to a first embodiment of this invention, FIG. 2 is a plan view showing the electric motor shown in FIG. 1, and FIG. 3 is a plan view showing an electric motor according to a second embodiment of this invention. 4 are plan views showing an electric motor according to a third embodiment of the present invention, and FIG. 5 is a sectional view showing a conventional electric motor. In the figure, 21: Rotating shaft 22: Rotating body 23: Disk mounting surface 24: Rotor yoke 25: Driving magnet 31: Stator core 32: Coil 34: Concave portion 35: Connecting portion 35a: Rotor side connecting surface 35b: Counter-rotor side connecting surface 37: Center line 38: Root portion 38a: Iron core tooth side root surface 38b: Concave side root surface 42: Sintered oil-impregnated bearing. In the drawings, the same reference numerals and the same symbols indicate the same or equivalent parts. Agent: Patent attorney Masuo Daikichi and 2 others

Claims (1)

[Scope of Claims] A rotary shaft rotatably supported; a rotor that rotates together with the rotary shaft and is provided with a ring-shaped driving magnet that generates a magnetic field from an outer circumference in a radial direction of rotation; , a stator located outside the rotor and having a plurality of coils wound around the stator core; The peripheral side is connected by the stator core,
An electric motor characterized in that the rotor-side connecting surface includes a concave portion formed as a concentric arc according to the outer shape of the drive magnet.