JPS6029993A - Disk drive motor - Google Patents

Abstract

PURPOSE:To reduce the space loss inside a hub and to decrease the thickness of a magnetic disk device by incorporating a torque generating part for a disk drive motor into the hub. CONSTITUTION:A rotor yoke 28 is fixed into a hub 24, and a cylindrical rotor magnet 29 obtained by magnetizing plural magnetic poles in division in the radial direction is provided into the yoke 28. A stator core 31 having a slot is fixed to a housing 30, and a stator coil 32 is wound round the core 31. In addition, a member holding a disk-shaped magnet 36 is provided to the housing 30 by means of a soft magnetic disk consisting of pole pieces 37 and 35. A magnetic fluid 34 is held in a gap formed between the inner circumference of each pole piece and the outer circumference of the yoke 28 by a magnetic flux passing through the gap. Thus it is possible to obtain a sealed structure to protect the motor part from dust.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a magnetic disk device in which a magnetic circuit is configured by a rotor yoke disposed within a hub, two pole pieces and a magnet disposed in a housing, and the rotor yoke and pole This invention relates to a disk drive motor in which a magnetic fluid is injected into the space between the rotor yoke and the rotor yoke to provide a dustproof seal.

FIG. 1 shows a #M perspective view of a conventional disk drive motor. In FIG. 1, the height between the magnetic disks is determined by a plurality of magnetic disks IH as magnetic recording/reproducing media, a disk spacer 2, and a disk clamp plate 3 is fixed to a hub 4 by screws or the like. The magnetic disk is held at a hub Km. The hub is fitted with the rotating shaft 5, and a ring 6 is arranged on the rotating shaft 5 by press-fitting or gluing, and a certain gap is formed between the ring and the upper pole piece 8 and the lower pole piece 10, which are arranged in the housing 12Vc. A magnetic circuit is constituted by the members holding the magnet 9, and the magnetic fluid 7 is held in the gap between the upper pole piece and the ring or the gap between the lower pole piece and the ring, and a dust-proof seal structure is provided at the rotating shaft portion. Further, one rotating shaft is supported by an upper bearing 11 and a lower bearing 13 fixed to the housing, and a rotor yoke 17 is further fixed to the rotating shaft.
The rotor yoke Vc generates torque by electromagnetic interaction in the rotor magnet by a stator core 14 in which a rotor magnet 18 is arranged and a housing VcW, and a stator coil wound around the stator core with a certain number of phases and a certain number of poles. . Note that this is a 16-digit motor board.

In a conventional disk drive motor as shown in FIG. 1, the torque-generating parts of the motor, such as the rotor magnet and stator coil, are separate from the hub.
There is a lot of wasted space inside the hub, and as the number of magnetic disks increases, the wasted space inside the hub increases, making it difficult to make the magnetic disk device thinner.
The space occupied by the motor also reduces the number of magnetic disks that can be mounted, making it difficult to increase the storage capacity of each magnetic disk device.

The present invention eliminates such drawbacks [7] and its purpose is to
An object of the present invention is to provide a disk drive motor in which a torque generating part of the disk drive motor is built inside a hub. Furthermore, the purpose of the seal is to make the entire disk drive motor dust-tight and sealed against the magnetic dinuks. Still another object is to reduce the loss of space in the disk drive motor and to make the magnetic disk device thinner.

Still another object is to increase the number of magnetic disks by reducing the space occupied by the disk drive motor, thereby increasing the full nil' storage capacity of the magnetic disk drive.

The present invention will be described in detail below based on examples.

FIG. 2 is a cross-sectional schematic diagram of a disk drive motor according to an embodiment of the present invention. In FIG. 2, a plurality of (four in FIG. 2) magnetic disks 21 as magnetic recording and reproducing media are:
The height between each magnetic disk is determined via the disk spacer 22, and the disk clamp plate 23 is connected to the hub 24.
The magnetic disk is held on the hub by fixing it with screws or the like. The hub is fitted with a rotating shaft 25, and the rotating shaft is supported by an upper bearing 26 and a lower bearing 27 fixed to the housing 30. A rotor yoke 28 is fixed inside the hub (however, the outermost cylindrical part of the rotor yoke may be arranged with a gap between it and the inside of the hub), and inside the rotor yoke is a cylindrical rotor that is divided into a plurality of magnetic poles and magnetized in the radial direction. A magnet 29 is arranged by adhesion or the like,
A stator core 31 having a slot in which a wire can be wound is fixed to the housing with a gap between the inner periphery of the rotor magnet and a stator coil 52 with a convex portion of the stator core Vc.
is wound with a plurality of phases and a plurality of convex poles, and by appropriately energizing the stator coil, rotational torque is generated by electromagnetic interaction with the rotor magnet. On the 33 motor board, the wire ends of the stator coils are processed, the position detection elements of the rotor magnets are arranged, etc. Since the magnetic disk part requires high dustproofness and must have a structure that is sealed from the outside, it is made of a circle magnetized in the thickness direction by two soft magnetic disks, the ten pole piece 37 and the lower pole piece 650. A member (consisting of 65, 36, and 37) holding a plate-shaped magneto y) 36 is disposed in the housing, and two parts are placed between the inner periphery of the upper and lower pole pieces and the outer periphery of the rotor yoke. The magnetic fluid 34 is held in at least one of the gaps by the magnetic flux passing through the gap to provide a dust-proof and sealed structure for the disk drive motor section.

In Figure 2, if the N pole of the magnet is on the upper pole piece side, the magnetic flux from Nff1 passes through the air gap from the upper pole piece to the rotor yoke, passes through the air gap, passes through the lower pole piece, and then passes through the magnet's S. It forms a closed magnetic circuit in which magnetic flux flows toward the pole. In this case, since it is easily affected by the magnetic flux of the rotor magnet, it is necessary to provide a gap for holding the magnetic fluid at a separate position from the position of the rotor magnet, or to bend the rotor yoke at a lower end surface with a bending angle of approximately 1.
Bend the rotor at an angle of 80 degrees and place a gap to hold the magnetic fluid as far away from the rotor magnet as possible, or arrange a cylindrical ring on the rotor yoke to form a magnetic circuit to hold the magnetic fluid. Treatment is required.

Further, FIG. 3 is a partially sectional schematic view of a disk drive motor according to still another embodiment of the present invention. In FIG. 3, the names of the parts corresponding to the numbers of each part are the same as in FIG. 2. In FIG. 3, members (35 and 36
and 37) is disposed on the inner circumference of the rotor of the housing, and the magnetic fluid 34 is disposed in at least one of the two gaps between the outer circumference of each of the upper and lower pole pieces and the inner circumference of the rotor yoke. It is held by magnetic flux passing through the air gap, creating a dust-proof and sealed structure for the disk drive motor section.

In this structure, since the inner peripheral part of the rotor yaw is sealed against dust by magnetic fluid, there is no loss of 1H of space in the outer peripheral part in the radial direction than in the outer peripheral part of the rotor yoke. In the case of FIG. 3, as in the case of FIG. 2, it is better to perform dustproof sealing in such a way that the influence of the magnetic flux of the rotor magnet is minimized.

According to the present invention, it is possible to provide a disk drive motor with a built-in torque generating part in the space inside the hub, and it is also possible to provide a dust-proof and sealed structure using magnetic fluid in which part of the rotor yoke is part of the magnetic circuit. Now, it is possible to seal the entire disk drive molding with a built-in hub against dust, the dust-proof seal structure is simple, and the number of parts required for the dust-proof sole structure is reduced compared to the conventional one. Due to the dust-proof sealing (one-way construction) of the Dinuku drive motor, the dust-proof performance of the magnetic disk part is improved, and normal magnetic disk recording and playback is possible. Since the disk drive motor is now a rotating part, the space that was occupied by the disk drive motor in conventional magnetic disk devices can be utilized, making it possible to make the magnetic disk device thinner.On the contrary, it is possible to make the magnetic disk device thinner. If the shape of the magnetic disk drive is permissible, it is possible to increase the storage capacity of the entire magnetic disk drive by arranging magnetic disks in the space conventionally occupied by the disk drive motor and increasing the number of magnetic disks. In the present invention, the structure of the disk drive motor is such that the space occupied by the disk drive motor in the magnetic disk device is minimized as much as possible, and a rotor yoke is used to further improve the dustproofness of the magnetic disk portion. It has a dustproof structure using a simple magnetic fluid, and its effectiveness is as described above.
Like very big six.

The present invention is particularly effective as a disk drive motor for a magnetic disk device, generally called a hard disk device, and is applied to a disk drive motor for a magnetic disk device in which the outer diameter of the magnetic disk is 8 inches or less and the outer diameter of the hub is relatively small. It is possible. In addition, it is also effective for reducing the thickness of disk drive motors that require dustproof properties and increasing He + * capacity.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional schematic diagram of a conventional Dinuku Drive Mol. FIG. 2 is a cross-sectional view of a disk drive motor according to an embodiment of the present invention. FIG. 3 is a partially sectional schematic view of a disk drive motor according to a further embodiment of the present invention. In FIGS. 2 and 3, 21 is a magnetic disk 22, a disk spacer 23, a digital clamp plate 241-t, a hub 25, a rotating shaft 26I-, an upper bearing 27, a lower bearing 28, a rotor yoke 29, a rotor magnetic 30 is a housing 5iFi stator core 32 stator coil 33 motor board 34 is a magnetic fluid 35 is a lower pole piece 36 is an upper pole piece 37. Applicant: Suwa Seikodai Co., Ltd. Figure 1

Claims (1)

[Claims] A magnetic disk as a magnetic recording/reproduction medium, a hub holding the magnetic disk, an a-ta yoke disposed inside the hub, and a plurality of magnetized a-ta fixed to the mosquito rotor yoke. In a disk drive motor having a stator core disposed with a certain gap between the rotor magnet and a stator coil wound around the stator core, two disc-shaped discs are attached to the nose ring to which the stator core is fixed. A member is disposed in which a disc-shaped magnet magnetized in the plate thickness direction is sandwiched between pole pieces, and a magnetic circuit is constituted by the two disc-shaped pole pieces and the rotor yoke of the magnet, and the pole piece A magnetic fluid is injected into at least one of two gaps between the pole piece and the rotor yoke, and the magnetic fluid is held by a magnetic flux passing through the gap between the pole piece and the rotor yoke. drive motor.