JPH0283868A - Oscillating motor for head access - Google Patents

Abstract

PURPOSE:To obtain a motor with large torque and a small inertia moment by surrounding the outer periphery of a fixed shaft attaching a circular coil in the periphery with the similar circular rotor providing a magnet at the inside and protruding and forming an arm having a head at the tip at the partial outer periphery of the rotor. CONSTITUTION:A driving motor for a head access making access to the reading and writing of an external memory having a rotary disk is constituted as follows. Namely, the circular coil 4 is wound to the outer peripheral central part of a fixed shaft 1 composed of a magnetic material, and on the inner peripheral surface of a rotor 2 of a magnetic material in the same way to surround this, the circular magnet 5 facing to the coil 4 is provided and the shaft 1 and the rotor 2 are pivotally supported with a bearing 7 positioned in the upper and lower directions. To a part of the outer peripheral surface of the rotor 2, plural steps of an arm 3 attaching a magnetic head 6 at the tip is protruded in parallel and the data are read and written by the head 6. Thus, a gap area can be widened and by energizing to the coil, strong torque can be obtained.

Description

[Detailed Description of the Invention] [Summary] Regarding a head access swing motor that accesses the read/write head of an external storage disk device, it is possible to have a compact configuration and a large gap area, and to greatly improve the torque constant. The aim is to provide a swing motor for head access that can reduce the moment of inertia as well as a fixed shaft made of magnetic material with a coil attached to the outer circumferential surface, and a rotating motor connected to the fixed shaft via a bearing. A rotor made of a magnetic material that is freely supported and has a plurality of permanent magnets attached to its inner peripheral surface so as to face the coil, and an arm that protrudes from the rotor and has a read/write head at its tip. Configure.

[Industrial application field]

The present invention relates to a head access swing motor for accessing a read/write head of a magnetic disk device, an optical disk device, etc. used as an external storage device of a computer or the like.

In recent years, disk devices such as magnetic disks and optical disks have been used as external storage devices for computers, and rotary positioners have become widely used as actuators that move the heads that write and read data on these disk devices. This is because it can be designed relatively compactly and has a simple structure.

FIG. 13 shows an example of a swing type motor commonly used in the past. In the swing type motor of this example, an arm 313 corresponding to the number of magnetic disks D is attached to a rotor 213 that swings around a rotating shaft 113, and a magnetic head 613 provided at the tip of this arm 313 Reads and writes to the magnetic disk D. A coil bobbin 913 is provided on the back side of the mounting surface of the arm 313 of the rotor 213, and a stator 813 with a permanent magnet 513 attached and forming a yoke is inserted into the coil 413 wound on the coil bobbin 813. A swing motor is constructed. Then, by energizing the coil 413, the rotor 213 swings, and the magnetic head 613 accesses the magnetic disk D.

However, in this structure, since the coil bobbin 913 is generally made of thin resin or the like, there is a problem that the rigidity is low. Therefore, the main resonance point of the vibration characteristics of the system is almost determined by this coil bobbin 913 (generally about 2 KHz), making high-speed access difficult. Furthermore, if the rotation radius of the coil bobbin 913 is increased to increase torque, the moment of inertia of the coil bobbin 913 increases, and in order to keep the coil 413 from moving, the coil 4
It's almost like having 13.

As described above, since the swing motor for head access requires torque for high-speed access, there has been a demand for a swing motor for head access that is compact and has a large torque.

[Conventional technology]

As a means to solve the problem of the swing motor shown in Fig. 13,
There is a swing motor for head access that uses a moving magnet type motor and has a coil placed on the fixed side (stator side).

FIGS. 14(a) and 14(b) are examples of the inner ring rotating type, in which a rotor 2 is attached to a shaft 114 rotatably attached to a stator 814 via a bearing 714 such as a bearing.
14 is fixed (or a portion of the rotor 214 is formed on the shaft), and an arm 314 is attached to one side of the rotor 214.
is provided protrudingly, and a permanent magnet 514 is attached to the back surface thereof. A coil 414 is attached to the inner surface of the stator 814 facing the permanent magnet 514.

In this case, the coil attachment parts of the rotor 214 and stator 814 are generally made of a magnetic material such as carbon steel or martensitic stainless steel, and also serve as a yoke, and the rotor 214 swings when the coil 414 is energized. .

FIGS. 15(a) and 15(a) are examples of an outer ring rotating type rocking morph, in which a fixed shirt 15 is fixed to a stator 815, and a bearing 7 such as a hair ring is attached to this fixed shaft 115.
A rotor 215 is rotatably attached via 14,
An arm 315 is protruded from one side of the rotor 215, and a permanent magnet 515 is attached to the back surface of the arm 315. A coil 415 is attached to the inner surface of the stator 815 facing the permanent magnet 515. In this case, the coil attachment parts of the rotor 215 and stator 815 are generally made of a magnetic material such as carbon steel or martensitic stainless steel, and also serve as a yoke, and by energizing the coil 415, the rotor 215 is centered around the fixed shaft 115. to sway.

[Problem to be solved by the invention]

However, in the conventional head access swing motor configured as described above, an arm assembly including an arm and a magnetic head is attached to a part of the rotor, so it is necessary to attach permanent magnets to the entire rotor. The rotational torque of the morph was still insufficient. That is, in practice, the area occupied by the magnet and coil is greatly limited in order to reduce the magnetic influence on the read/write head and the magnetic disk, and in an outer ring rotating type swing motor as shown in FIG. The attractive force of the permanent magnets acts on the rotor section of the stator, and in order to keep this constant over the motor's oscillation range, the rotor section must be placed larger than the magnet section. There is a problem that the area is greatly limited.

An object of the present invention is to solve the problems of the conventional swing motor for head access, to have a compact structure, and to be able to design the mounting of coils and magnets on the rotor and stator without being subject to positional restrictions. Another object of the present invention is to provide an excellent swing motor for head access, which can have a large gap area, greatly improve the torque constant, and reduce the moment of inertia.

[Means for Solving the Problems] FIG. 1 shows a principle configuration diagram of a swing motor for head access according to the present invention that achieves the above object.

As shown in FIG. 1, the head access swing motor of the present invention is a head access swing motor that accesses a read/write head of an external storage device equipped with a rotating disk. For this purpose, the fixed shaft I is made of a magnetic material, and a coil 4 is attached to its outer peripheral surface. Then, a rotor 2 made of magnetic material is connected to this fixed shirt via a bearing 7)
It is rotatably supported by I, and a plurality of permanent magnets 5 are attached to its inner peripheral surface so as to face the coil 4. Furthermore, an arm 3 is provided to protrude from the rotor 2, and a read/write head 6 is provided at the tip end of the arm 3.

[Effect]

According to the swing motor for head access of the present invention, the coil 4
．． Both permanent magnets 5 can be placed inside the rotor 2 over the entire circumference of the rotating shaft, allowing for a wide gap area.Furthermore, since the fixed shaft 1 and rotor 2 are made of magnetic materials, the fixed shaft → coil 4 → permanent A permanent magnet magnetic circuit is constructed such as magnet 5 → rotor 2 → permanent magnet 2 → coil 4 → fixed shaft 1, and the swing motor can swing with strong torque by energizing the coil.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 2 is a sectional view showing the structure of an embodiment of the head access swing motor of the present invention. In this embodiment, the housing 82 is composed of a base 23 and a cover 21, and a gasket 28 is attached to the joint portion. The fixed shaft 12 is fixed to the inside of the base 23 and the cover 21 by bolts or the like, and the center part of the fixed shirt eye 2 is bulged and has a thick diameter. A coil 42 is wound around the large diameter portion of the fixed shaft 12 in alignment in the axial direction, and the return portion of the coil 42 is connected to the stepped portion between the large diameter portion and the small diameter portion of the fixed shirt eye 2 and the bearing 72. It is folded into the space between. In addition, this coil 42
The ends of the windings are located within the axis of the fixed shaft 12 and the base 2.
It is drawn out to the outside through a ventilation hole 27 provided in 3.

A rotor 22 is rotatably held on the outside of the fixed shaft 12 via a bearing 72 such as a ball bearing attached to a narrow diameter portion of the fixed shaft 12. and,
Inside this rotor 22 there is a coil 4 of fixed shirt day 2.
A plurality of permanent magnets 52 are arranged at positions facing the rotor 2, and arms 32 corresponding to the number of magnetic disks D are protruded from the outside of the rotor 22.

A seal member 29 is attached to the cover 21 around the attachment portion of the fixed shaft 12 via an O-ring 26 with screws, etc., and a contact portion 30 between the seal member 29 and the inner circumferential surface of the rotor 22 is It has a magnetic fluid seal. Furthermore, the lower surface of this seal member 29 and the aforementioned bearing 72
A preload spring 25 is interposed between the bearing 72 and the bearing 72, and the bearing 72 is preloaded in the axial direction by the preload spring 25. Further, a seal member 24 is attached to the base 23 around the attachment part of the fixed shaft 12 via an O-ring 26, and the inner peripheral surface of this seal member 29 and the ring member 20 attached to the lower end of the rotor 22. A magnetic fluid seal is also applied to the contact portion 31 with the. These treatments are performed to prevent outside air and grease, etc. scattered from the bearing 72 from entering the enclosure of the magnetic disk.

Next, examples of how to wind the coil 42 attached to the outer circumference of the fixed shaft 12 and the polarity of the permanent magnet 52 attached to the rotor 22 in the embodiment configured as described above will be explained using FIGS. 3 to 10. explain.

Note that ■ and ■ in the figures indicate the winding direction of the coil, and arrows indicate the direction of magnetic flux (FIGS. 3 and 7) or the winding direction of the coil. Further, although the case of four poles is shown in these figures, this is for explanation and there is no particular restriction on the number of poles.

FIG. 3 schematically shows a horizontal cross section of the swing motor shown in FIG. This is an example. In this way, when the polarities of the adjacent permanent magnets 52 are different, the winding directions of the adjacent coils 42, that is, the direction in which the current flows are always opposite. Coil 4 like this
4 (a), (b), and 5 (a)
), (b), and the winding methods shown in FIGS. 6(a) and (t)). That is, the winding method shown in FIG.
The winding method shown in Fig. 5 is a method in which the coil 42 is divided into two parts, and the winding method shown in Fig. 6 is a method in which the coil 42 is fixed by changing the winding direction at the upper and lower return parts. This is a method of winding it around the shaft 12.

FIG. 7 also schematically represents a horizontal cross section of the swing motor shown in FIG. This is an example where they are arranged together.

In this way, when two adjacent permanent magnets 52 have the same polarity, the winding direction of the coil 42, that is, the direction in which the current flows, also becomes the same. As shown in FIG. 7, if permanent magnets 52 of the same polarity are placed on the side of the arm attachment part of the rotor 22, the magnetic flux will be transferred to the yoke attachment part of the rotor 22 and the part where the normal balancer is attached on the opposite side. Since it does not pass through, it is possible to make the magnetic material part in this part thinner. Moreover, such a method of winding the coil 420 is shown in FIGS. 8(a), (b), FIGS. 9(a), (b), and the first
There is a winding method as shown in Figure 0 (aL (b). That is,
The winding method shown in FIG. 8 is a method in which the coil 42 is crossed at the upper and lower return parts, and the winding method shown in FIG.
The winding method shown in FIG. 10 is a combination of the winding method shown in FIG. 8 and the winding method shown in FIG. 9.

The method of winding the coil is shown in Figures 4 to 6 and Figure 8 above.
The winding method is not limited to the winding methods shown in FIGS. 10 to 10, and only examples of winding methods are shown here.

11 and 12 show other embodiments of the arrangement of coils and permanent magnets in the head access swing motor of the present invention, and FIG. 11 shows the rotor in the two-pole head access swing motor. Coil 411 on the outer periphery of 211
FIG. 12 shows the arrangement of the permanent magnets 511 on the inner circumference of the fixed shirt H21, and FIG. It shows.

The outer ring rotation type head access swing motor of the present invention shown in the above embodiments has a fixed shaft, whereas conventional outer ring rotation type head access swing motors are generally large in the radial direction. Since the stator is used as a stator, it can be made extremely compact and with a small number of parts.

As a result, the moment of inertia of the motor becomes small, and a large acceleration can be obtained even with a small driving force, allowing high-speed access. On the other hand, since there are not many restrictions on the arrangement of the magnets and coils, a sufficient torque constant can be obtained. Also,
The head access swing motor of the above embodiment is isolated from the inside air by a magnetic fluid seal and ventilated from the outside air by a ventilation hole, so there is no risk of rust due to gas generation from the coil or poor surface treatment of the magnet. There is no need to make the standards stricter than with internal air installations. Furthermore, since the rotor has a cylindrical structure and the magnets are bonded, the rotor has sufficient rigidity.

The outer ring rotating structure uses a fixed shaft, which increases the rigidity of the housing, and the coil, which is the heat source, is glued or attached to the fixed shaft, and is connected to the outside air through ventilation holes, which is advantageous for off-track driving. It is. Moreover, since the yoke, ie, the fixed shaft, facing the magnet has a cylindrical shape, the magnetic attraction force does not change due to rotation. Furthermore, since the magnetic circuit is shielded by the rotor, there is little magnetic leakage.

〔Effect of the invention〕

As explained above, the swing motor for head access of the present invention has a compact configuration, and the mounting of coils and magnets on the rotor and stator can be designed without restrictions on the position, so the gap area can be reduced. Make it bigger,
This has the effect that the torque constant can be greatly improved and the moment of inertia can also be reduced.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the principle configuration of a swing motor for head access according to the present invention, FIG. 2 is a sectional view showing the structure of an embodiment of the swing motor for head access according to the present invention, and FIG. A cross-sectional view showing the arrangement of the magnets and coils of the swing motor, FIG.
L (b) is a diagram showing how to wind the coil in Figure 3 into four parts, Figures 5 (a) and (b) are diagrams showing how to wind the coil in Figure 3 in two parts, and Figure 6 is a diagram showing how to wind the coil in two parts. Fig. 3 is a diagram showing how to wind the coil around a fixed shaft; Fig. 7 is a sectional view showing another arrangement of the magnets and coils of the swing motor in Fig. 2;
Figure (a). (b) is a diagram showing how to wind the coil in Figure 7 in an intersecting manner, Figures 9 (a) and (b) are diagrams showing how to wind the coil in Figure 7 in two parts, and Figure 10 is a diagram showing how to wind the coil in two parts. FIG. 11 is a sectional view showing an embodiment in which the present invention is applied to a two-pole swing motor, and FIG. 13 is a cross-sectional view showing an embodiment in which the invention is applied to a three-pole swing motor, FIG. 13 is a perspective view showing the configuration of a conventional head access swing motor, and FIGS. 14(a) and (b)
15) are cross-sectional views and vertical cross-sectional views of a conventional inner ring rotation type head access swing motor, and FIGS. 15(a) and 15(b) are cross sectional views of a conventional outer ring rotation type head access swing motor. , is a vertical cross-sectional view. 1... Fixed shaft, 2... Rotor, 3... Arm, 4... Coil, 5... Permanent magnet, 6... Head, 7... Bearing, 12... Fixed shaft , 22...
・Rotor, 32... Arm, 42... Coil, 52
...Permanent magnet, 62...Head, 72...Bearing.

Claims (1)

[Claims] 1. A head access swing motor for accessing a read/write head of an external storage device equipped with a rotating disk, the fixed motor being made of a magnetic material and having a coil (4) attached to its outer circumferential surface. A shaft (1) is rotatably supported by the fixed shaft (1) via a bearing (7), and a plurality of permanent magnets (5) are attached to the inner peripheral surface so as to face the coil (4). The coil (
4) A swing motor for head access that performs head access by energizing. 2. In the swing motor for head access according to claim 1, the mounting part of the bearing (7) of the fixed shaft (1) has a small diameter, and the return part of the coil (4) is on the small diameter side. Swing motor for folded head access.