JPH04178161A - Motor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electric motor, and particularly to an electric motor that rotates a recording medium of a magnetic recording device that reads and writes magnetic recording signals on a recording medium such as a magnetic disk. It is.

[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. 4 is a longitudinal sectional view of a conventional electric motor, and FIG. 5 is a side view of the conventional electric motor.

In the figure, (31) is the rotating shaft located in the center, (
32) is a disk holding member that is fitted and fixed to the upper part of the rotating shaft (31), and the magnetic disk (3) is mounted on the upper disk mounting surface (32a). Reference numeral (33) denotes a drive bin provided on the outer periphery of the disk holding member (32), which rotates the magnetic disk (3). (3
4) is a flange (34a) fixed to the frame (35).
), and the rotary shaft (31) is supported by a bearing (36) attached to the inner peripheral surface of the cylindrical bearing holder. A stator (38) having a donut-shaped iron core (37) is attached to the outer periphery of the bearing holder (34) concentrically with the rotating shaft (31), and this stator (38) is attached to the frame (3
5) and the flange (34a) of the bearing holder (34).
) is fixed to the outer periphery of the screw (39). The iron core (37) of the stator (38) has a fill (40
) are wound, and these iron cores (37) and coils (
40) is insulated from the iron core (37) by an insulating coating (41) made of synthetic resin coated on the outer surface. (42) is a rotor attached to cover the outside of the stator (38), the center of a lid-shaped rotor yoke (43) is fixed concentrically with the rotation shaft (31) by a screw (44), and A driving permanent magnet (45) facing the stator (38) with a slight gap is fixed to the inner peripheral surface of the cylindrical portion of the rotor yoke (43).

(46) is an index detection element attached to the frame (35), and (47) is the index detection element (47).
6) and the rotor yoke (43) of the rotor (42).
The index detection element (46) and the index detection magnet (47) constitute an index detection mechanism, which generates a signal of one pulse per rotation. (48)
, (49) is a magnetic head that reads and writes magnetic recording signals on both sides of the magnetic disk (3), and is attached to the frame (35) and is slidable on a support shaft (51) fixed via a member (50). The sliding member (52) is configured to allow linear movement.

This type of electric motor has a rotor (4) on the outside of the stator (38).
2) is called the outer rotor type.

Next, the operation of the conventional electric motor configured as described above will be explained.

Disc mounting surface (32a) of disc holding member (32)
When the magnetic disk (3) is set on the magnetic disk (3) and detected by a magnetic detection element (not shown), the coil (40) wound around the iron core (37) of the stator (38) is energized based on this. . On the other hand, the permanent magnet (45) for driving the rotor (42)
) generates magnetic force in the radial direction, and thus generates rotational torque in the rotor (42) through magnetic interaction with the stator (38). When the rotor (42) starts rotating, the rotating shaft (31) also rotates, and the drive bottle (33) is inserted into the window hole of the magnetic disk (3) to apply rotational force to the magnetic disk (3). give. Further, the magnetic head (48) and the magnetic head (49) read and write magnetic recording signals through head windows on both sides of the magnetic disk (3) while moving linearly.

[Problem to be solved by the invention] A conventional electric motor is configured as described above, and has a rotor (42
) are located outside the stator (38), or the magnetic head (48) and magnetic head (49), which move linearly in the radial direction with respect to a recording medium such as a magnetic disk (3), are located outside the rotor (4).
2) and cannot be arranged on the same plane as the rotor (42) and stator (38), which limits the ability to make the magnetic recording device thinner. For this reason, the rotor (42) is connected to the stator (
Inner rotor type electric motors located inside the magnetic recording device (38) are increasingly being used in magnetic recording devices.

However, when adopting this inner rotor type electric motor, the end face corner of the rotating shaft on the circuit board side is at a right angle, so
When the rotating shaft tilts and lifts due to some kind of impact, such as when removing a magnetic disk, the corner of the end face digs into the inner peripheral surface of the bearing and does not return to its original position. Furthermore, during assembly, the workability of inserting the rotating shaft into the bearing was not good.

In view of this, the present invention is designed to easily return to its original position when the rotating shaft is lifted due to some kind of impact without causing the corner of the end face of the rotating shaft on the circuit board side to dig into the inner peripheral surface of the bearing, and to rotate the rotating shaft during assembly. An object of the present invention is to provide an inner rotor type electric motor that can be made thinner and whose shaft can be easily inserted into a bearing.

[Means for Solving the Problems] The electric motor according to the present invention has a rotary shaft that is pivotally supported in the center and has a chamfered radius of 0.2 to 0.4+m on the end face corner on the circuit board side. , a rotor having a driving permanent magnet that generates magnetic force in the radial direction and rotating integrally with the rotating shaft; and a plurality of coils disposed outside the rotor and wound around an iron core to drive the rotor. and a stator that generates rotational force in the rotor through magnetic action with permanent magnets.

[Function] In the present invention, R is provided at the corner of the end face of the rotating shaft on the circuit board side.
Since the shaft is chamfered to a value of 0.2 to 0.4w+11+, even if the rotating shaft is tilted or lifted due to some kind of impact, it will not dig into the inner circumferential surface of the bearing.

Therefore, the rotating shaft easily returns to its original position. Furthermore, during assembly, it can be easily inserted into the bearing. In addition, since the chamfer size is 0.2 to 0.4 mm,
Not only can the above-mentioned necessary effects be expected, but also the effective shaft span within the bearing can be ensured, and the rotational shaft can be prevented from falling.

[Example] Hereinafter, an example of the present invention will be described based on FIGS. 1 to 3.

FIG. 1 is a longitudinal sectional view of an electric motor according to an embodiment of the present invention, FIG. 2 is a plan view of the electric motor shown in FIG. 1 with the magnetic shield plate removed, and FIG. be.

In the figure, (1) is a rotating shaft disposed in the center, and the end face corner (1a) thereof is chamfered to r=0.2 to 0.4 mm. (2) is a disk holding member that is fitted and fixed to the upper part of the rotating shaft (1), and a magnetic disk (3) is mounted on the upper disk mounting surface (2a). (4) is a drive pin provided on the outer periphery of the disk holding member (2), and (5) is a drive pin whose lower part is vertically connected to the center of a flat metal circuit board (6) via a screw (7). A cylindrical bearing holder (8) is fixed to the bearing holder (8).
This is a bearing that is attached to the inner circumferential surface of the rotating shaft (1) and pivotally supports the rotating shaft (1).

A ring-shaped rotor yoke (9) is fixed and integrated with the lower part of the disk holding member (2) on the outside of the bearing holder (5). (10) is a driving permanent magnet formed in a ring shape and attached to the outer peripheral surface of the rotor yoke (9). A rotor (11) is constituted by the disk holding member (2), the rotor yoke (9), and the driving permanent magnet (10).

A stator (12) is disposed outside the driving permanent magnet (10) of the rotor (11) at a position facing the driving permanent magnet (10) with a small gap. (1
3) constitutes a stator (12), which has a notch (
13a), the entire core is coated with an insulating coating (14) made of synthetic resin.

The axial position of this iron core (13) is adjusted by a spacer (15), and it is fixed on the circuit board (6) concentrically with the rotating shaft (1). Inside the iron core (13), a coil (16) is wound around iron core teeth obtained by equally dividing the inner periphery, and a bridging portion (1
3b) is formed.

(17) is a magnetic shield plate attached to the outer periphery of the iron core (13) and covers the upper part of the driving permanent magnet (10) and stator (12), and (18) is attached to the bottom surface of the disk holding member (2). The index detection element (20) is mounted on the circuit board (6) facing the magnetized index signal detection surface (19), and the rotation speed detection surface (20) is magnetized on the lower surface of the disk holding member (2). (FG magnetized surface), the rotational speed of the motor is detected as a frequency.

(21) and (22) are magnetic heads that read and write magnetic recording signals on both sides of the magnetic disk (3), and the circuit board (6)
The support shaft (24) is fixed via the member (23).
), the iron core (13
) is inserted into the notch (13a) to allow linear movement in the radial direction.

This type of electric motor has a rotor (12) inside a stator (12).
1) is called the inner rotor type.

Next, the operation of the electric motor of this embodiment configured as described above will be explained.

A magnetic disk (3) is set on the disk mounting surface (2a) of the disk holding member (2), and when detected by a magnetic detection element (not shown), a magnetic disk is inserted into the iron core (13) of the stator (12) based on this. The wound coil (16) is energized, and rotational torque is generated in the rotor (11) by magnetic interaction with the driving permanent magnet (10) of the rotor (11).

Then, when the rotor (11) starts rotating, the rotation axis (1
) also rotates together, and the drive pin (4) is connected to the magnetic disk (3
) is inserted into the window hole of the magnetic disk (3) to apply rotational force to the magnetic disk (3). Further, a magnetic head (21) and a magnetic head (22
) reads and writes magnetic recording signals through head windows on both sides of the magnetic disk (3) while moving in a straight line.

The electric motor configured as described above is connected to the magnetic field (21
) and magnetic head (22), rotor (11), stator (
12), the magnetic recording device can be made thinner. Specifically, the thickness of the electric motor, that is, the distance t from the mounting surface (2a) of the disk holding member (2) to the lower surface of the circuit board (6) shown in FIG. can.

Next, the effect of chamfering the end face corner (1a) of the rotating shaft (1) will be explained.

The end face corner (1a) on the circuit board (6) side of the rotating shaft (1) is chamfered to r=0.2 to 0.4sIll, so it will not be exposed to any impact when removing the magnetic disk (3). Even if the rotating shaft (1) is tilted up or down, the bearing (8
) The end face corner portion (1a) does not dig into the inner circumferential surface of the end face (1a). Therefore, the rotating shaft (1) easily returns to its original position. Also,
During assembly, it is easy to insert into the bearing (8). Note that if the chamfer dimension r is 0.4+++++++ or more, since the thickness t of the electric motor is as thin as 3 to 6111 mm, it will not be possible to secure an effective shaft span with the bearing (8), and the rotating shaft (1) will collapse. There is a risk of rotational vibration. Further, if the chamfer dimension r is 0.2 mm or less, it is too small and the above effect can hardly be expected.

In this way, the electric motor of the above embodiment has a rotary shaft that is pivotally supported in the center and has a chamfering process of r=0.2 to 0.4+++m on the end face corner (1a) on the side of the circuit board (6). (1)
and a driving permanent magnet (10) that generates a magnetic saw in the radial direction.
) and rotates integrally with the rotating shaft (1).
11) is disposed outside the rotor (11), and a plurality of coils (16) are wound around an iron core (13), and the rotor is moved by magnetic action with the driving permanent magnet (10). (11
) and a stator (12) that generates rotational force.

Therefore, according to the above embodiment, due to the chamfering of r = 0.2 to 0.411II11 applied to the end face corner (1a) on the circuit board (6) side of the rotating shaft (1), the rotating shaft ( 1) will not dig into the inner circumferential surface of the bearing (8) even if it is lifted up at an angle. Therefore, the rotating shaft (1) can be easily returned to its original position. And bearing (8)
There is no damage to the inner circumferential surface or the rotating shaft (1). Further, during assembly, it can be easily inserted into the bearing (8).

By the way, when carrying out the present invention, the bearing (8) of the above embodiment can be applied to either a sliding bearing or a rolling bearing.

[Effects of the Invention] As described above, the electric motor of the present invention is pivotally supported in the center,
It has a rotating shaft with a chamfered radius of 0.2 to 0.4+ms on the end face corner on the circuit board side, and a driving permanent magnet that generates magnetic force in the radial direction, and rotates integrally with the rotating shaft. a stator, which is disposed outside the rotor, has a plurality of coils wound around an iron core, and generates rotational force in the rotor through magnetic interaction with the driving permanent magnet. It is something that Therefore, by chamfering the end face corner on the circuit board side of the rotating shaft with an R of 0.2 to 0.4++u++, even if the rotating shaft is tilted or lifted due to some kind of impact, the end face corner will be on the inner peripheral surface of the bearing. The rotating shaft can be easily returned to its original position without digging into the shaft.

Furthermore, during assembly, it can be easily inserted into the bearing.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an electric motor according to an embodiment of the present invention, FIG. 2 is a plan view of the electric motor shown in FIG. 1 with the magnetic shield plate removed, and FIG. FIG. 4 is a longitudinal sectional view of a conventional electric motor, and FIG. 5 is a side view of the conventional electric motor. In the figure, 1: rotating shaft 1a: end face corner 6: circuit board 10: driving permanent magnet 11: rotor 12: stator 13: iron core 16: coil. In the drawings, the same reference numerals and the same symbols indicate the same or equivalent parts. Agent: Patent attorney Masuo Daikichi and two others Figure 2

Claims (2)

[Claims] (1) A rotary shaft that is pivotally supported in the center and has a chamfered radius of 0.2 to 0.4 mm on the corner of the end face on the circuit board side, and a driving permanent magnet, and the rotary shaft and a rotor that rotates integrally with the rotor; and a stator that is disposed outside the rotor and has a plurality of coils wound around an iron core and that generates rotational force in the rotor between the drive permanent magnet and the rotor. An electric motor characterized by comprising: (2) The electric motor according to claim 1, wherein the electric motor has a thickness of 3 to 6 mm.