JP2007068281A - Motor, and disk drive with same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor for preventing a torque from decreasing, preventing a cogging from increasing and having a winding easily wound. <P>SOLUTION: A rotor (R) is provided with an annular magnet (8), and supported through a bearing to s stator (S) comprising a core (6) having a plurality of salient poles (6p1-6p9) opposite to the magnet (8) and an annular base (6k) and coils (71-79) wound onto a plurality of the salient poles. A plurality of the salient poles have columnar sections (6a1-6a9) radially protruding from the base to an interior, and opposite sections (6b1-6b9) circumferentially extending in the predetermined circumferential width (V) at an end of the columnar sections. One circumferential angle pitch of each columnar section in a plurality of the salient poles is increased. The other circumferential angle pitches are an equiangular pitch P. An angle is an equal angle Ps, and formed by a line drawn between the center of the predetermined circumferential width in the adjacent opposite sections and the rotational center (O). The angle pitch P is less than the angle Ps. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a motor and a disk device including the motor, and more particularly to a core shape of a magnetic circuit in a motor that rotationally drives a disk.

As a disk device for recording data on a disk-shaped recording medium or reproducing data from the recording medium, a magnetic disk device using a magnetic disk such as a hard disk or a flexible disk as a recording medium, a CD-R or the like as a recording medium An optical disc apparatus using an optical disc such as a DVD-R is known.
In order to rotationally drive these disks, a motor is mounted on the disk device, and an example of the motor will be described with reference to FIGS.

This conventional motor has an inner rotor structure in which a rotor on the inner peripheral side of the stator core rotates.
The rotor 104 includes a hub 102 and a magnet 108, and the hub 102 is formed by processing a stainless material.
An annular magnet 108 is fixed to the outer peripheral surface of the hub 102 by press-fitting or bonding. Electrodeposition coating is applied to the surface of the magnet 108.

On the other hand, the stator 103 includes a stator core 106, a coil 107, and a sleeve 109, and is fixed to the motor base 105. The motor base 105 is formed by press-molding a nickel-plated iron plate or stainless steel.
The sleeve 109 is fixed to a hole provided in the motor base 105.
The stator core 106 is made of a magnetic material such as a silicon steel plate, and has an annular outer peripheral portion and a plurality of salient poles protruding inward from the outer peripheral portion, and the surface thereof is subjected to electrodeposition coating.
And it is fixed to the inner surface of the peripheral wall raised from the bottom surface of the motor base 105 by press drawing.

As shown in FIG. 5, each salient pole of the stator core 106 includes a column part 106 a that protrudes radially inward from the annular part, and a tip part 106 b that extends in a direction orthogonal to the radial direction at the tip of the column part 106 a. , And is substantially T-shaped.
An electric wire is wound around the column portion 106a of each salient pole to form a coil 107 (see FIG. 6).

When fixing the motor base of the stator core 106, in order to ensure conduction between the stator core 106 and the motor base 105, a part of the electrodeposition coating is peeled off from the outer peripheral surface of the stator core 106, and the exposed core 106 surface and the motor base 105 are separated. Both are fixed while applying a conductive adhesive so that an electrical connection can be obtained between the two.
In the stator core 106, nine salient poles 106p are formed at equal angular pitches in the circumferential direction.
That is, the salient pole pitches θ1 to θ9 shown in FIG. 5 are all equal to 40 °.

FIG. 6 shows a state where the coil 107 is wound around the stator core 106.
As shown in this figure, for example, if the angle width of each formed coil 107 is 35 °,
The gap angle between adjacent coils 107 is only 5 °.

By the way, when the motor is mounted on, for example, a magnetic disk device, it is necessary to consider the position of the magnetic head 11 for recording or reproducing data on the disk.
Specifically, the magnetic head 11 does not interfere with the mounted motor, and the magnetism generated by energizing the coil when driving the motor affects the magnetic head 11 to cause recording signals and reproduction. It is to prevent an error from occurring in the signal.

For this purpose, for example, the magnetic head 11 is disposed so as to access only the surface of the disk 10 on which the motor is not disposed.
It is desired that a pair of magnetic heads 11 be provided on both sides of the disk so that both sides of the disk can be accessed. An example of a motor that achieves this is described in Patent Document 1.
The motor described in Patent Document 1 has a ring-shaped stator core provided with a missing portion that is partially missing, and furthermore, a salient pole is used to prevent cogging from increasing due to the effect of the missing portion. The position is shifted.
By providing such a missing part, it is possible to arrange a sensor for detecting the rotation of the magnetic head or the rotor in this missing part, and it is possible to reduce the size of the device equipped with this motor and the motor itself. Become.

  However, in the motor described in Patent Document 1, the torque is reduced by providing the missing portion in the core, and the torque is also reduced by shifting the position of the salient pole. There was a problem that the decrease would be significant.

On the other hand, there is an attempt to allow the rotation detection sensor of the rotor to be disposed between the salient poles without providing a missing portion in the core, and an example thereof is described in Patent Document 2.
In this patent document 2, the tip of the pair of salient poles adjacent to the rotation detection sensor is evenly arranged in the circumferential direction, and the angular pitch of the column is rotated by making it wider than the angular pitch of the other salient poles. A spindle motor configured to ensure a space for arranging the detection sensor is described.

FIG. 7 shows an application of this technical idea to the stator core of FIG. 6 described above.
The stator core 116 in FIG. 7 has an angular pitch of 48 ° with respect to the two salient poles 106-1 and 106-9 on the lower side of the nine salient poles 116-1 to 116-9. It is assumed that the angle pitch of other salient poles is widened to 35 °. In addition, coils 117-1 to 117-9 are wound around each salient pole with an angular width of 35 ° as in the case of FIG.

  In this configuration, an angular gap of 13 ° is obtained between the coil 117-1 and the coil 117-9, and a rotation detection sensor can be arranged in this gap. Further, if the annular portion corresponding to this gap is missing, it is possible to dispose the magnetic head in the missing portion.

However, in this configuration, the angular spacing between the coils in the salient poles with a wide angular pitch and the salient poles adjacent thereto, that is, the coils 117-1 and 117-2, and the coils 117-9 and 117- The angular interval of 8 is only 1 °, which is an extremely narrow interval.
Therefore, when winding the coil around these salient poles, there is a problem that it is difficult to insert the nozzle through the wire rod of the winding machine between the salient poles, making it difficult to wind the coils.

For this reason, there is a possibility that the salient pole and the nozzle collide with each other and damage the nozzle, and when the coil cannot be wound in an aligned manner, the winding width of the coil varies, and the coil itself can be wound by interfering with each other. There is a high possibility of disappearing.
That is, there is a problem that winding of each coil is extremely difficult.

As described above, a motor that can easily be wound without causing a decrease in torque or an increase in cogging, and a motor having such merits, so that both sides of the disk can be accessed. Therefore, there is a demand for a small and high capacity disk device.
JP 2003-125568 A JP 2002-191159 A

Therefore, the problem to be solved by the present invention is to provide a motor that can be easily wound without causing torque reduction and without increasing cogging.
In addition, a small and high capacity disk device that has a motor for driving a disk that can be wound easily without reducing torque, and that does not increase cogging, and that can record or reproduce on both sides of the disk. It is to provide.

In order to solve the above problems, the present invention has the following means [1] to [3].
[1] A rotor (R) having an annular magnet (8) is connected to a plurality of salient poles (6p1 to 6p9) facing the outer peripheral surface (8a) of the magnet (8) and a substantially annular base (6k). And a stator (S) having a core (6) having coils and coils (71 to 79) wound around the plurality of salient poles (6p1 to 6p9), respectively. In the motor
Each of the plurality of salient poles (6p1 to 6p9) includes a column portion (6a1 to 6a9) projecting radially inward from the base portion (6k), and a circumferential direction at a tip portion of the column portion (6a1 to 6a9). And having a predetermined width (V) and extending in the circumferential direction (6b1-6b9),
In the plurality of salient poles (6p1 to 6p9), the angular pitch in the circumferential direction of each of the column portions (6a1 to 6a9) is increased at one place and is set to an equal angular pitch P at another place,
An angle formed by a straight line connecting the center of the predetermined width (V) in the circumferential direction and the center (O) of the rotor in each of the adjacent facing portions (6b1 to 6b9) is an equal angle Ps,
The motor (50) is characterized in that the angle pitch P and the angle Ps satisfy P <Ps.
[2] The motor (50) according to claim 1, wherein the base (6) has a missing portion (6L) between the salient poles (6p1, 6p9) corresponding to the one place.
[3] A disk device (51) for recording or reproducing data on a disk-shaped recording medium (10),
A motor for rotating the recording medium (10), and a magnetic head (11b) for writing or reading the data on the recording medium (10),
The motor (50) according to claim 2, wherein the motor is a disk device (51), wherein the magnetic head (11b) is arranged in the missing portion (6L).

According to the present invention, it is possible to obtain a motor that can be wound easily without torque reduction and without increasing cogging.
There is also a small and high-capacity disk device that has a disk drive motor that does not reduce torque, does not increase cogging, and can be easily wound, and can record or reproduce on both sides of the disk. can get.

An embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a sectional view for explaining an embodiment of the motor of the present invention.
FIG. 2 is a plan view of the main part in the embodiment of the motor of the present invention.
FIG. 3 is a schematic plan view for explaining an embodiment of the disk device of the present invention.

FIG. 1 is a cross-sectional view of a motor 50 according to the embodiment. In this figure, the motor 50 and the magnetic head 11 and the disk 10 included in the disk device 51 in a state where the motor 50 is mounted on the disk device 51 are combined. It is described.
The disk device 51 is an HDD (hard disk drive), and a hard disk 10 is attached as a recording medium to the hub 2 of the mounted motor 50. The hard disk 10 is a double-sided recording disk, and magnetic heads 11a and 11b are arranged on each side so that each side can be accessed independently.
This motor 50 is a motor that rotates at 3600 times / min. An inner core that rotates a rotor R that is disposed on the inner peripheral side of the stator core 6 by fixing the stator core 6 around which the coil 7 is wound to the motor base 5. It has a rotor structure.
The motor 50 is three-phase driven and is configured with nine salient poles and nine slots.

First, the stator S will be described in detail.
The stator S includes a motor base 5 formed by cutting aluminum die casting or pressing aluminum or iron plate, a sleeve 9 and a stator core 6 fixed to the motor base 5, and winding around the stator core 6. The coil 7 is configured.

The motor base 5 has a through hole 5a, and a cylindrical sleeve 9 made of a copper alloy or a stainless material is fixed to the through hole 5a by adhesion or press fitting.
The motor base 5 has a peripheral wall portion 5c raised from the bottom portion 5b by press drawing, and the outer peripheral surface of the stator core 6 is fixed to the inner peripheral surface of the peripheral wall portion 5c. The stator core 6 is formed in a substantially annular shape having a missing portion 6L (details will be described later).

  The sleeve 9 has a flange portion 9a extending radially outward on the opposite side to the motor base 5, and a ring-shaped thrust plate 22 is fixed to the outer peripheral surface 9b with a gap from the flange portion 9a. .

Next, the rotor R will be described in detail.
The rotor R includes a hub 2 having a cup shape with an outer peripheral portion 2b, and a ring-shaped magnet 8 made of a magnetic material.

The hub 2 is formed of stainless steel, and a shaft portion 2a is integrally provided at the center thereof.
A cylindrical outer tube portion 18 is inserted into the outer peripheral surface of the shaft portion 2a.
Further, when the motor is mounted on the disk device 50, the disk 10 is mounted on the upper surface side of the hub 2 while being clamped by the clamper 20.
On the outer peripheral surface 2b1 of the outer peripheral portion 2b of the hub 2, a ring-shaped magnet 8 equally magnetized to 12 poles is bonded and fixed.

  The magnet 8 is a neodymium rare earth resin magnet, and the surface thereof is electrodeposited to prevent dust generation.

A thrust ring 21 is fixed to the inner peripheral surface 2 b 2 of the outer peripheral portion 2 of the hub 2.
The rotor R described above is rotatably supported with respect to the stator S by a fluid dynamic pressure bearing.
Specifically, with respect to the radial direction, the rotor R is supported by a radial dynamic pressure bearing constituted by the inner surface of the sleeve 9, the outer peripheral surface of the outer cylindrical portion 18 and the lubricating oil filled in the gap, and the thrust direction. Is arranged so that the thrust ring 21 fits into the gap between the flange portion 9a of the sleeve 9 and the thrust plate 22, both end surfaces in the axial direction of the thrust ring 21, and the lower surfaces of the opposing flange portions 9a The rotor R is supported by a thrust dynamic pressure bearing constituted by an upper surface of the thrust plate 22 and lubricating oil or the like filled in a gap between these surfaces.

In the disk device 51 on which the motor 50 is mounted, a magnetic head 11b that accesses the lower surface 10b of the disk 10 in FIG.
FIG. 3 shows a schematic plan view of the disk device 51. A hard disk 10 and a motor 50 that rotationally drives the hard disk 10 are provided in a housing 51a of the disk device 51, and the magnetic head 11 is disposed in a space SP between the coil 71 and the coil 79 in the missing portion 6L of the stator core 6. It is configured. Details of the coils 71 and 79 and the space SP will be described later.

Next, the stator core 6 and the like will be described in detail.
Stator core 6 is formed by laminating silicon steel plates.
As shown in FIG. 2, the stator core 6 includes an annular portion 6k that is a substantially annular base part with a part missing, and nine pieces extending from the annular portion 6k to the inside thereof at an equal angular pitch P in the circumferential direction. It has salient poles 6p1 to 6p9.
The annular portion 6k has a missing portion 6L formed between the salient pole 6p1 and the salient pole 6p9.
Since the equal angle pitch P is set to 39 ° in this embodiment, the angle pitch between the salient pole 6p1 and the salient pole 6p9 adjacent to the missing portion 6L is 48 °.

Each of the salient poles 6p1 to 6p9 includes a column part 6a1 to 6a9 projecting radially inward from the annular part 6k, and a tip part 6b1 to 6b9 extending in a direction perpendicular to the radial direction at the tip of the column part 6a1 to 6a9. And is substantially T-shaped. The tip portions 6 b 1 to 6 b 9 are opposed portions that face the outer peripheral surface 8 a of the annular magnet 8.
Moreover, the coils 71-79 are wound around each pillar part 6a1-6a9 (refer FIG. 3).

The circumferential widths V1 to V9 of the tip portions 6b1 to 6b9 of the salient poles 6p1 to 6p9 are all formed with the same width V.
In addition, regarding the tip portions 6b1 to 6b9, the angular pitch Ps formed by the straight line connecting the center of the circumferential width V of each tip portion and the rotation center O of the hub 2 of the rotor R is set to be equal. . In this embodiment, Ps = 40 °.

On the other hand, the widths W1 to W9 of the pillar portions 6a1 to 6a9 are all formed equally.
In addition, the angular pitches P other than between the column part 6a1 and the column part 6a9 in each of the column parts 6a1 to 6a9 are all set equal as described above. In this embodiment, P = 39 °, and the pitch is different from the angular pitch Ps of the tip.

Here, in this embodiment, in the middle of the plurality of salient poles, that is, in the fifth salient pole 6p5 out of the nine poles, the center lines of the tip 6b5 and the column 6a5 are made to coincide with each other. Yes.
Therefore, due to the difference between the angular pitches P and Ps, the center line of the tip portion and the center line of the column portion are shifted at the salient poles other than the fifth, and the shift amount (angle) is the fifth salient pole. The salient pole is farther away from the pole 6p5.
In this embodiment, the amount is 4 ° at the first and ninth salient poles 6p1 and 6p9 where the amount of deviation is the largest.

A state in which a coil is wound around each salient pole of the stator core 6 described above will be described with reference to FIG.
The coils 71 to 79 are wound around the column portions 6a1 to 6a9 of the salient poles 6p1 to 6p9 with a winding angle width of 35 °.
Accordingly, the angular interval between the coils other than between the first coil 71 and the ninth coil 79 is constant at 39 ° −35 ° = 4 ° because the inter-column angle pitch P is 39 °. Become.

On the other hand, the angular interval between the first coil 71 and the ninth coil 79 is 48 ° −35 ° = 13 ° since the angular pitch between the pillars is 48 °.
That is, a space SP of 13 ° is secured between the coil 71 and the coil 79 corresponding to the missing portion 6L.
The disk device 51 of the embodiment has a configuration in which the magnetic head 11b is disposed in the space SP.

  As described above in detail, in the motor of the embodiment, since the circumferential angular pitch of the tip portions 6b1 to 6b9 at each of the salient poles 6p1 to 6p9 is equal, there is no change in the magnetic circuit, so the rotation accuracy is not affected. Does not increase noise and vibration.

  In addition, since the angular interval between the coils can be further increased, the coils can be easily aligned and wound. Moreover, even if the winding width of the coil varies, the coils do not interfere with each other, so that winding is easy and the winding machine is not damaged.

  Further, when the magnetic head is disposed in the reserved space SP, interference between the magnetic head and the coil on the motor side is avoided physically and magnetically, so that the disk device can be made small. it can.

  Furthermore, access to the surface of the disk on the motor side becomes possible, and recording or reproduction on both sides of the disk becomes possible by cooperating with the magnetic head on the opposite side, so that a high capacity disk device can be obtained.

  The embodiment of the present invention is not limited to the configuration and procedure described above, and it goes without saying that modifications may be made without departing from the scope of the present invention.

The circumferential position and the width of each column portion with respect to each tip portion can be arbitrarily set since the performance is not affected as long as the shape does not protrude in the circumferential direction with respect to the tip portion.
The missing portion 6L may not be provided in the annular portion 6k of the stator core 6. That is, the complete annular stator core 6 may be used. Also in that case, the space SP is obtained inside the annular portion 6k, and a rotation detection sensor or the like can be arranged.
What is arranged in the space SP is not limited to the magnetic head or the rotor rotation detection sensor, but may be another member.
The embodiment can be similarly applied to other coil configurations such as 6 coils and 12 coils that are frequently used in a three-phase drive motor, and to an 8-coil configuration frequently used in a two-phase motor. The number of coils is not limited.
In the embodiments, the HDD has been described as the disk device. However, the present invention is not limited to this, and can be applied to a disk device using a magnetic disk such as a flexible disk or an optical disk such as a CD or DVD as a recording medium. is there.

It is sectional drawing explaining the Example of the motor of this invention. It is a top view of the principal part in the Example of the motor of this invention. 1 is a schematic plan view illustrating an embodiment of a disk device according to the present invention. It is sectional drawing for demonstrating the conventional motor. It is a top view for demonstrating the conventional motor. It is another top view explaining the conventional motor. It is another top view for demonstrating the conventional motor.

Explanation of symbols

2 hub 2a shaft portion 2b outer peripheral portion 2b1 outer peripheral surface 2b2 inner peripheral surface 5 motor base 5a through hole 5b bottom portion 5c peripheral wall portion 6 stator cores 6a1 to 6a9 column portions 6b1 to 6b9 tip portions (opposing portions)
6k annular portion 6L missing portion 6p1-6p9 salient pole 7 (71-79) coil 8 magnet 8a outer peripheral surface 9 sleeve 9a flange portion 9b outer peripheral surface 10 disk (hard disk)
11 (11a, 11b) Magnetic head 18 Outer cylinder portion 20 Clamper 21 Thrust ring 22 Thrust plate 50 Motor 51 Disk device 71-79 Coil P, Ps Angular pitch R Rotor S Stator SP Space V, V1-V9 (at the tip) Width W1 to W9 (column part) width

Claims (3)

A rotor having an annular magnet is provided for a stator having a core having a plurality of salient poles facing the outer peripheral surface of the magnet and a substantially annular base, and a coil wound around each of the plurality of salient poles. In a motor that is supported rotatably through a bearing,
Each of the plurality of salient poles has a column portion projecting radially inward from the base portion, and a facing portion extending in the circumferential direction with a predetermined width in the circumferential direction at a tip portion of the column portion, Have
The angular pitch in the circumferential direction of each of the pillar portions in the plurality of salient poles is increased at one location and equal to the angular pitch P at the other location,
The angle formed by the straight line connecting the center of the predetermined width in the circumferential direction and the center of the rotor in each of the adjacent facing portions is an equal angle Ps,
The motor characterized in that the angle pitch P and the angle Ps satisfy P <Ps.   The motor according to claim 1, wherein the base has a missing portion between the salient poles corresponding to the one place. A disk device for recording or reproducing data on a disk-shaped recording medium,
A motor that rotationally drives the recording medium, and a magnetic head that writes or reads the data to or from the recording medium,
3. The disk device according to claim 2, wherein the magnetic head is disposed in the missing portion.

Images