JPH05284710A - Motor - Google Patents

Abstract

PURPOSE:To avoid the troubles between a magnetic shielding plate (MS) and a coil and reduce the thickness of a motor by a method wherein a stator is provided outside and a part of the outer circumference of the stator is made to retreat radially or opened and the stator coil is electrically insulated with a thin film member. CONSTITUTION:A bearing component 2 which supports a rotary shaft 1 so as to rotate freely is vertically attached and fixed to a motor frame 4 to which a stator 3 is attached. The stator 3 is fixed to the motor frame 4 with screws with a spacer 5 therebetween concentrically with the bearing component 2. A coil 6 is wound on the inside of the core 3a of the stator 3. A recess 3c which is made to retreat toward the inner circumference side is formed on the outer circumference of the part of the core 3a where the coil 6 is not wound. A magnetic shielding plate (MS) 12 is fixed above the coil 6 with screws to shield a leakage flux to a magnetic recording medium 11. A thin film member 16 having electrical insulating properties is fixed with the MS 12 with screws between the MS 12 and the coil 16. Therefore, the moving line of magnetic heads 14 and 15 agrees with the recess 3c and a rotor 10, the stator 3 and the magnetic heads 14 and 15 can be provided on an approximately same plane, so that the thickness reduction can be achieved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric motor, and more particularly to an electric motor for rotating a recording medium of a magnetic recording apparatus having a magnetic head for reading and writing magnetic recording signals on a recording medium such as a magnetic disk.

[0002]

2. Description of the Related Art The conventional electric motor of this kind has a structure as disclosed in, for example, Japanese Utility Model Laid-Open No. 60-135863. That is, as shown in FIGS. 3 and 4, the rotating shaft 1 having the holding mechanism 7 for holding the magnetic recording medium 11 is fixed to the frame 20 via two bearings on the holding mechanism side and the non-holding mechanism side. It is rotatably held by a cylindrical bearing holder 21. A stator 22 having a donut-shaped iron core is fixed to the outside of the bearing holder 21 with screws sandwiching the frame 20, and a coil 23 is wound around the iron core.
At the end of the rotary shaft 1 on the side opposite to the holding mechanism, a yoke 25 having a permanent magnet 24 fixed to the stator 22 is fixedly screwed to the inner peripheral surface of the rotary shaft 1 to form a rotor 26. The permanent magnets 24 generate a magnetic force in the radial direction, and generate a rotating torque by the current supplied to the coil 23 wound around the iron core of the stator 22.
In the figure, reference numeral 27 is an index detecting element which constitutes an index detecting mechanism, and 28 is an index detecting magnet which also constitutes the index detecting mechanism. The index detecting mechanism generates a signal of one pulse per one rotation. Further, 14 and 15 are magnetic heads, which are configured to be linearly movable by a sliding member on a support shaft fixed to the frame 20 via a mounting member.

This type of electric motor is called an outer rotor type in which the rotor 26 is located outside the stator 22, and the rotor 22 is based on the detection of magnetism by a magnetic detection element (not shown). The coil 23 wound around the iron core is energized and controlled to rotate.

[0004]

In the above-described conventional electric motor, the rotor 26 is located outside, and the magnetic heads 14 and 15 that linearly move in the radial direction with respect to the magnetic recording medium 11 are placed in the plane position of the rotor 26. However, it is difficult to reduce the thickness of the magnetic recording device.

The present invention has been made in order to solve the conventional problems, and an object thereof is to improve the reliability of an electric motor which can contribute to a reduction in thickness of a magnetic recording device.

[0006]

An electric motor according to the present invention can pass magnetic flux in a radial direction to a rotor having a permanent magnet fixed to generate a magnetic force in a radial direction with respect to a central rotating shaft. An inner rotor type electric motor having a plurality of coils wound around an iron core, and a stator arranged outside the rotor for generating a rotational force in the rotor by magnetic action with a permanent magnet, A part of the outer circumference of the iron core of the stator is retracted or cut out to the inner circumference side to form a recess or open portion having no coil, and the coil of the stator is covered with a magnetic shield plate at the upper side, and A thin film material having electrical insulation is interposed between the magnetic shield plate and the magnetic shield plate.

[0007]

In the electric motor according to the present invention, the stator is located outside and a part of the outer periphery thereof is retracted or opened in the radial direction. It can be placed in the plane of the rotor or stator, and the coil of the stator is protected and electrically insulated by the thin film material, so that trouble does not occur with the coil even if the magnetic shield plate is located close to the coil. become.

[0008]

1 is a sectional view of an electric motor showing an embodiment of the present invention, and FIG. 2 is a front view showing the electric motor applied to a magnetic recording apparatus.

In the figure, a bearing component 2 which rotatably supports a rotary shaft 1 is rotatably fitted and fixed to a flat plate-shaped motor frame 4 to which a stator 3 is attached. The stator 3 is screw-fixed to the bearing component 2 on the motor frame 4 via a spacer 5 at a position concentric with the bearing component 2.
A plurality of coils 6 are wound inside the. The coil 6 is wound around 15 continuous iron core teeth obtained by dividing the inner circumference of the iron core 3a into 18 equal parts, and the inner diameter portion of the iron core 3a corresponding to three continuous iron core teeth is bridged. It is formed as the portion 3b. That is, the outer circumference of the portion of the iron core 3a where the coil 6 is absent is formed as a recess 3c that is recessed toward the inner circumference.

The number of coils 6 is 3 × m (m is a positive integer of 2 or more), and the number of missing coils is 3 × n (n is a positive integer of 1 or more). Inside the stator 3, there is a rotor 10 in which a permanent magnet 9 is fixed to the outer circumference of a ring-shaped rotor yoke 8 made of a ferromagnetic metal integrated with a holding mechanism 7 that is press-fitted into the rotating shaft 1 or integrally shaped. It is configured to rotate freely. The holding mechanism 7 is a disk-shaped magnetic recording medium 11
The permanent magnet 9 generates a magnetic force in the radial direction and faces the inner peripheral surface of the stator 3 with a predetermined gap. Above the coils 6 of the stator 3, a ring-shaped metal whose planar shape covering the end faces of the coils 6 and the iron core 3a on the side of the holding mechanism is substantially equal to the planar shape of the iron core 3a of the stator 3 is formed. The magnetic shield plate 12 is screwed to the iron core 3a by several mounting legs 13 to shield the magnetic fluxes leaking to the magnetic recording medium 11 held by the magnetic heads 14 and 15 and the holding mechanism 7. A thin film material 16 having electrical insulation is interposed between the magnetic shield plate 12 and the coil 6 so as to be fastened together by a mounting screw of the magnetic shield plate 12. The thin film material 16 covers the end surface of the iron core 3a together with the coil 6 to protect the coil 6.

In this electric motor, the iron core 3a is partially recessed
Since it is c, an unbalanced force is remarkably generated in the magnetic force acting in the radial direction with respect to the permanent magnet 9 of the rotor 10, so that the bearing portion always acts as a force in a certain direction as a preload. As a result, shaft runout of the rotary shaft 1 is prevented. In the application to the magnetic recording device, as shown in FIG. 2, the magnetic heads 14 and 15 are linearly movable by a sliding member on a support shaft fixed to the motor frame 4 via a mounting member. Of the rotor 10, the stator 3, and the magnetic heads 14 and 15 by aligning the moving line of the rotor with the recess 3c of the iron core 3a.
Can be arranged in substantially the same plane, and the magnetic recording device can be made thinner. Further, also in the electric motor itself, since the coil 6 is protected by the thin film material 16, the gap between the magnetic shielding plate 12 and the coil 6 can be made as small as possible, and the coil 6 can be made thin without fear of damage and the like. The property is improved.

[0012]

As is apparent from the above description of the embodiments, according to the present invention, since the stator is on the outer side and a part of the outer periphery thereof is receded or opened in the radial direction, the movement line of the magnetic head is changed. By aligning with this, members such as the magnetic head can be housed in the plane of the rotor and the stator,
Moreover, since the coil of the stator is protected and electrically insulated by the thin film material, trouble does not occur with the coil even when the magnetic shield plate is located in the vicinity of the coil, and it is possible to improve reliability and reduce the thickness. .

[Brief description of drawings]

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

FIG. 2 is a front view showing a state in which the electric motor of the invention is applied to a magnetic recording device.

FIG. 3 is a sectional view of a conventional electric motor.

FIG. 4 is a front view showing a state in which a conventional electric motor is applied to a magnetic recording device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 rotating shaft 3 stator 3a iron core 3c recess 4 motor frame 6 coil 7 holding mechanism 9 permanent magnet 10 rotor 11 magnetic recording medium 12 magnetic shielding plate 16 thin film material

Claims (1)

[Claims] 1. A rotor, which is rotatably held in a direction perpendicular to a frame and has a permanent magnet for generating a magnetic force in a radial direction fixed to a rotating shaft having a mechanism for holding a disk-shaped recording medium, A plurality of coils are wound around an iron core that can pass magnetic flux in the radial direction, and a stator arranged outside the rotor that generates a rotational force in the rotor by a magnetic action with the permanent magnet. In the electric motor provided, a part of the outer circumference of the iron core of the stator is retracted or notched to the inner circumference side,
A concave portion or an open portion having no coil is formed, and the stator is provided with a magnetic shield plate covering the coils above the plurality of coils, and between the magnetic shield plate and the coil. An electric motor characterized by interposing a thin film material having electrical insulation.