JPH04172949A - Motor - Google Patents

Abstract

PURPOSE:To obtain a thin motor having a protected stator coil in which electric short circuit does not occur between different phase coils by covering an exposed part of a coil wound around a stator core with an electromagnetic shield having coil side surface covered with an insulating film. CONSTITUTION:Exposed part of a coil 32 wound around a stator core 31 is covered with an electromagnetic shielding board 50 having coil 32 side surface covered with an insulating film. Since the stator coil 32 is protected by the magnetic shielding board 50 and does not face directly against a magnetic disc or the like under naked state, the coil 32 does not interfere with a magnetic disc case or the like and protected against damage. In particular, since the coil 32 side surface of the magnetic shielding board 50 is covered with the insulating film 51, electrically insulated state is sustained even upon inadvertent contact between the coil 32 and the magnetic shielding board 50 and thereby electric short circuit through the magnetic shielding board 50 is prevented between different phase coils 32. According to the constitution, a highly reliable and safe thin motor can be obtained.

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. 3 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 that fixes 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 magnetically attached. It engages with a window hole (not shown) in a rotary plate fixed to the disk.

(16) is an index detection element disposed on the frame (]3), (17) is an index detection magnet disposed on the rotor (3), and this index detection element (
]6) 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.

[Problem to be solved by the invention] In the conventional outer rotor type electric motor as described in 1.
A certain amount of space was required 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 (not shown). In the past, there were limits to how thin electric motors could be made. For this reason, it has been considered to use a thin inner rotor type electric motor in which the stator (7) is located outside the rotor (3).

However, in this type of electric motor, there is no frame (13) between the stator (7) and rotor (3) and the magnetic disk and magnetic head, and the stator coil is also exposed directly to the magnetic disk case etc. It was facing me. Therefore, there is a risk that the magnetic flux generated by the current flowing through the stator coils will directly reach the magnetic disk or the magnetic head, and have an adverse effect on recording and reproduction. Furthermore, there is a risk that the coil may be damaged due to interference with the magnetic disk case or the like.

Furthermore, simply protecting the coils with an electromagnetic shielding material may cause an electrical short circuit between coils of other phases if they accidentally come into contact.

Therefore, this invention prevents the leakage of magnetic flux caused by the current flowing through the stator coils, protects the stator coils, and creates a thin motor that does not cause electrical short circuits between the coils of other phases. The challenge is to provide this information.

[Means for Solving the Problems] The electric motor according to the present invention has a rotatably supported rotary shaft (21), rotates integrally with the rotary shaft (21), and applies a magnetic field to the outer circumference in the direction of the rotation radius. A rotor is provided with a ring-shaped driving magnet (25) and a plurality of coils (3
2) covered the exposed portions of the stator wound thereon and the coil (32) wound around the stator core (31), and the surface of the coil (32) side was covered with an insulating coating (51). and magnetic shielding means made of an electromagnetic shielding material.

In the present invention, the coil (32) side surface is coated with an insulating coating (
A coil ( 3
2), the stator coil (
32), the leakage magnetic flux does not directly reach the magnetic disk or magnetic head, and the stator coil (32) is protected by the magnetic shielding means covered with the insulating film (51). Therefore, the coils (32) of the other phases are not short-circuited through the magnetic shielding means without directly facing the magnetic disk case or the like in a naked state.

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

FIG. 1 is a sectional view showing an electric motor according to an embodiment of the present invention.

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.

(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);
(45) is a spacer interposed between the stator core (31) and the frame (40). (50) is a magnetic shielding plate made of a ferromagnetic electromagnetic shielding material such as an iron plate, which covers the exposed part of the coil (32) wound around the stator core (31), and also serves as a magnet for driving the rotor. (25) covers the exposed portion on the disk mounting surface (23) side. (51
) is an insulating coating that covers the surface of the magnetic shielding plate (50) on the coil (32) side, and this insulating coating (51) is coated with a resin such as vinyl chloride or coated with electrically insulating paint. It is formed by

This magnetic shielding plate (50) has an external shape as shown in FIG. FIG. 2 is a perspective view showing a magnetic shielding plate used in the electric motor of this embodiment.

In the figure, (50a) is a mounting leg formed by bending at three places on the magnetic shielding plate (50), and (50b) is a concave shape formed to match the shape of the stator core (31) of the stator. This is a flange for the section.

This magnetic shielding plate (50) is fixed to the frame (40) together with the stator core (31) by screws (44) via mounting legs (50a). In addition, this magnetic shielding plate (5
0) is covered with an insulating film (51).

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. The outer circumferential surface of the core at locations corresponding to the three core teeth is concave toward the inner circumferential surface, and the inner circumferential surface is connected by the core. This concave portion allows the magnetic head to move without interfering with the stator, and the concave portion flange (50b) of the magnetic shielding plate (50) fits into this concave portion. In addition, a rotor drive magnet (25
), for example, N and S poles are magnetized in the direction of the rotation radius of the rotor at 24 equal parts around the entire circumference. 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 to generate rotational torque in a fixed 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 for moving the magnetic head, unlike the conventional outer rotor type. Since the gap for avoiding interference between the stator and rotor and the magnetic disk and magnetic head can be omitted, as in the case of the electric motor, the thickness of the entire electric motor can be reduced.

Furthermore, in this embodiment, the coil (32) is wound around the stator core (31) of the stator using magnetic shielding means made of an electromagnetic shielding material whose surface on the side of the coil (32) is covered with an insulating coating (51). Exposed parts are covered. Therefore, the magnetic flux generated by the current flowing through the stator coil (32) can be prevented from leaking, and the leaked magnetic flux does not directly reach the magnetic disk or magnetic head, unlike in the conventional case. Further, the stator coil (32) is protected by the magnetic shielding means covered with the insulating film (51), and does not directly face the magnetic disk case or the like in a naked state as in the conventional case.

As mentioned above, the electric motor of this example has a sintered oil-impregnated bearing (
a rotating shaft (21) rotatably supported by 42);
A link-shaped drive magnet (2
5), a stator located outside the rotor and having a plurality of coils (32) wound around the stator core (31); A magnetic shielding plate (50) (magnetic shielding means) made of an electromagnetic shielding material that covers the exposed portion of the wound coil (32) and whose surface on the side of the coil (32) is covered with an insulating coating (51). ing.

That is, in the electric motor of this embodiment, the stator iron core (31) of the stator is provided with a magnetic shielding plate (50) (magnetic shielding means) made of an electromagnetic shielding material whose coil (32) side surface is covered with an insulating coating (51). ) The exposed portion of the coil (32) is covered.

Therefore, the magnetic flux generated by the current flowing through the stator coil does not directly reach the magnetic disk or the magnetic head, so there is no possibility that it will adversely affect recording and reproduction by the magnetic disk and magnetic head. In addition, the coil (32) of the stator is protected by a magnetic shielding plate (50) and does not directly face the magnetic disk etc. in a bare state, so the coil (32)
There is no risk of interference and damage to the magnetic disk case, etc.

In particular, since the surface of the magnetic shielding plate (50) on the side of the coil (32) is covered with an insulating coating (51), the coil (32) may be accidentally
2) and the magnetic shielding plate (50), the electrically insulated state is maintained, so the coil (32) of the other phase
) will not be electrically short-circuited through the magnetic shielding plate (50). Moreover, in this embodiment, since the rotor driving magnet (25) is also covered with the magnetic shielding plate (50), leakage magnetic flux from the driving magnet 1-(25) can be shielded at the same time. Therefore, there is no need to provide magnetic shielding means exclusively for the rotor drive magnet (25).

As a result, a thin electric motor with high reliability and safety is obtained.

By the way, in the above embodiments, the insulating coating (51) was formed by coating a resin such as vinyl chloride, or by applying an electrically insulating paint, or by other methods. 51) may be formed. For example, a sheet of vinyl chloride or the like may be stretched over the magnetic shielding plate (50), and if a commercially available vinyl chloride steel plate is used, there is no need to form an insulating coating (51). In short, the coil (
32) and the magnetic shielding plate (50) may come into contact with each other by mistake, as long as they do not become electrically conductive.

[Effects of the Invention] As described in 2 below, the electric motor of the present invention includes a rotatably supported rotating shaft, a rotor that rotates integrally with the rotating shaft,
A coil comprising a stator located outside the rotor and a magnetic shielding means made of an electromagnetic shielding material whose coil side surface is covered with an insulating film, the coil being wound around the stator core of the stator with the magnetic shielding means. With a simple configuration that covers the exposed part of
Since the magnetic flux generated by the current flowing through the stator coil does not directly reach the magnetic disk or magnetic head, there is no risk of it having an adverse effect on recording and reproduction by the magnetic disk and magnetic head. Since it is protected by a magnetic shielding means and does not face the magnetic disk case directly, there is no risk of damage to the coil, and even if the coil accidentally comes into contact with the magnetic shielding plate, it will remain electrically insulated. Reliability and safety are improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an electric motor according to an embodiment of the present invention, FIG. 2 is a perspective view showing a magnetic shielding plate used in the electric motor of this invention, and FIG. 3 is a sectional view showing a conventional electric motor. be. In the figure, 21: rotating shaft 22: rotating body 23: disk mounting surface 24: rotor yoke 25: driving magnet 31: stator core 32: coil 5o: magnetic shielding plate 51: insulating coating. In the drawings, the same reference numerals and the same symbols indicate the same or equivalent parts.

Claims (1)

[Scope of Claims] A rotating shaft rotatably supported; a rotor that rotates integrally with the rotating shaft and is provided with a ring-shaped driving magnet that generates a magnetic field on its outer periphery; and the rotor. A stator is located outside the stator core and has a plurality of coils wound around it, and an electromagnetic stator that covers the exposed part of the coil wound around the stator core and whose coil side surface is covered with an insulating coating. An electric motor characterized by comprising magnetic shielding means made of a shielding material.