WO2007094113A1

WO2007094113A1 - Spindle motor and information recording/reproducing device

Info

Publication number: WO2007094113A1
Application number: PCT/JP2006/324150
Authority: WO
Inventors: Masakazu Hirata; Manabu Oumi; Norio Chiba; Kunio Nakajima; Ryuji Iijima; Toshifumi Ohkubo
Original assignee: Seiko Instruments Inc.; Toyo University
Priority date: 2006-02-13
Filing date: 2006-12-04
Publication date: 2007-08-23
Also published as: JPWO2007094113A1

Abstract

A spindle motor is provided with a shaft arranged along a rotating axis; a stator plate (16) for supporting the shaft; a rotating body rotatably inserted into the shaft; a rotor plate (19) which has an opposing plane (19a) opposing the stator plate and rotates with the rotating body; a plurality of rotor electrode sections (25) arranged on the opposing plane of the rotor plate at every prescribed angle (θ1); a plurality of stator electrode sections (26) arranged on the surface of the stator plate at every angle (θ2) which is narrower than a prescribed angle; a voltage applying means for rotating the rotor plate in a constant direction by a static force by applying a driving voltage to the selected stator electrode section; and a dynamic pressure groove (23) which is arranged on the opposing plane of the rotor plate and generates a pressure in a direction of separating the rotor plate from the stator plate. The rotor electrode sections are previously grounded.

Description

Specification

Spindle motor and information recording / reproducing apparatus

Technical field

The present invention relates to a spindle motor that rotationally drives a recording medium such as a hard disk incorporated in various electronic devices, and an information recording / reproducing apparatus having the spindle motor.

Background art

[0002] Conventionally, various motors have been provided as various types of motors for rotating a hard disk (recording medium) incorporated in various electronic devices such as a notebook personal computer and a portable video player.

[0003] For example, a spindle motor having a hydrodynamic bearing device with a large load capacity is known (see, for example, Patent Document 1). This spindle motor is composed of a shaft having a collar, a sleeve that slides along the outer peripheral surface of the shaft and the lower surface of the collar, and an upper thrust that slides along the upper surface of the collar. A bearing device is provided. A first dynamic pressure generating groove is provided on each of the outer peripheral surface of the shaft and the upper and lower surfaces of the collar portion. In addition, second dynamic pressure generating grooves are provided on the lower surface of the upper thrust, the inner peripheral surface and the upper end surface of the sleeve, respectively.

[0004] In particular, this fluid dynamic pressure bearing device has both an outer peripheral surface of a shaft and an inner peripheral surface of a sleeve.

Since the first dynamic pressure generating groove and the second dynamic pressure generating groove are provided, the pressure generated in the bearing gap increases. Therefore, the load capacity can be increased, and the spindle motor can be rotated at a high speed and with high accuracy.

[0005] However, this fluid dynamic pressure bearing device has to have a shaft with a certain height in order to ensure the rigidity of the bearing. For this reason, it has been difficult to reduce the thickness of the fluid dynamic bearing device. Therefore, it has been difficult to reduce the thickness of the spindle motor itself.

[0006] In particular, with recent miniaturization of electronic devices, the size of the disk itself is also becoming smaller. For example, discs with a diameter of lin or 0.85in have been developed, and high performance digital It has begun to be used in video cameras and small portable music players. As electronic devices and disks become smaller, motors that drive disks will be required to be smaller and thinner in the future.

[0007] However, the spindle motor described above has been difficult to meet such needs. Therefore, a gas dynamic pressure bearing motor is known as a motor that is thinner (see, for example, Patent Document 2).

[0008] This gas dynamic pressure bearing motor has a conical shaft, a sleeve formed of a magnetic material along the shape of the shaft, a drive mechanism such as a magnet and a coil that rotates the sleeve, and a sleeve that is magnetically arranged on the shaft side. It has a permanent magnet that pulls with attractive force. In particular, since the sleeve has a conical shape, the height can be kept low, and the thickness can be reduced as compared with the spindle motor.

Patent Document 1: JP 2002-372039 A

Patent Document 2: Japanese Patent Laid-Open No. 2003-35311

Disclosure of the invention

However, the conventional apparatus described above still has the following problems.

[0010] That is, the device described in Patent Document 2 described above has a force that can be reduced in thickness by a conical sleeve, and a drive mechanism such as a permanent magnet or a coil that rotates the sleeve. Since it is an essential component, it was not possible to make it thinner.

The present invention has been made in view of such circumstances, and an object of the present invention is to enable a recording medium to be rotated stably and with low vibration, and to achieve a further reduction in thickness as compared with conventional ones. It is an object of the present invention to provide a spindle motor and an information recording / reproducing apparatus having the spindle motor.

The present invention provides the following means in order to solve the above problems.

The spindle motor of the present invention is a spindle motor that rotates a disk-shaped recording medium capable of recording various types of information about a rotation axis, and is a shaft arranged along the rotation axis. And a stator plate arranged along a plane perpendicular to the rotation axis and supporting a base end side of the shaft, and inserted with a certain clearance from the shaft, When the rotating body rotates, the rotating body has a rotating body that is rotatable around the rotation axis and has a holding portion for holding the recording medium on an outer peripheral surface, and a conductive fluid supplied to the gap. A fluid dynamic pressure bearing portion that supports at least a radial force of the rotor, a rotor plate that has a facing surface facing the stator plate, is fixed to the base end side of the rotating body, and rotates together with the rotor plate, A plurality of rotor electrode portions that are provided on opposite surfaces and are arranged at predetermined angles in the circumferential direction around the rotation axis, and a circumferential direction that is provided on the surface of the stator plate and that is centered on the rotation axis A plurality of stator electrode portions arranged at an angle narrower than the predetermined angle, and a driving voltage applied to the selected stator electrode portion of the plurality of stator electrode portions for a predetermined time!] , The rotor plate in a certain direction by electrostatic force A voltage applying means for rotating; and a dynamic pressure groove provided on an opposing surface of the rotor plate and generating pressure in a direction in which the rotor plate is separated from the stator plate as the rotor plate rotates. The plurality of rotor electrode portions are grounded via at least the rotor plate and the fluid.

[0014] In the spindle motor according to the present invention, first, a rotating body is inserted and attached to a shaft whose base end side is supported by a stator plate with a certain gap therebetween. It can be rotated around its axis. At this time, a conductive fluid such as oil is supplied to the gap between the shaft and the rotating body. Further, the face plate fixed to the base end side of the rotating body is in a state where the facing surface faces the surface of the stator plate. As a result, the rotor electrode portion and the stator electrode portion are similarly opposed to each other.

[0015] Further, the opposing surface of the rotor plate is provided at predetermined angles toward the circumferential direction around the rotation axis.

A plurality of rotor electrode portions are provided (for example, every 30 degrees), and dynamic pressure grooves are provided separately from the rotor electrode portions. In addition, a plurality of stator electrode portions are provided on the surface of the stator plate at an angle narrower than the predetermined angle (for example, every 20 degrees) in a circumferential direction around the rotation axis. Due to the difference in the positional relationship between these two electrode portions, the stator electrode portion is always located between the adjacent rotor electrode portions.

Here, the driving voltage is applied to the selected stator electrode portion among the plurality of stator electrode portions for a predetermined time by the voltage applying means. Specifically, the drive voltage is applied to the stator electrode portion located on the rotation direction (constant direction) side of the rotor electrode portion. In this case, multiple Since the rotor electrode portion is grounded in advance through at least the rotor electrode portion and the conductive fluid, a positive voltage and a negative voltage were applied to the applied stator electrode portion and the rotor electrode portion, respectively. become. As a result, positive and negative charges are induced on the surfaces of both electrode portions, and electrostatic forces (electrostatic attractive force) are generated that attract each other.

[0017] Then, due to the horizontal component of the electrostatic force, the rotor electrode portion gradually moves toward the applied stator electrode portion. Then, at the same time that the rotor electrode portion has moved to a position completely opposed to the applied stator electrode portion, the voltage application means stops applying to the first stator electrode portion and at the same time starts moving the rotor electrode portion. A drive voltage is applied for a predetermined time to the next stator electrode portion positioned on the rotation direction (constant direction) side. Thereby, the operation | movement mentioned above is repeated and a rotor electrode part moves again.

As a result, the rotor plate and the rotating body can be rotated around the rotation axis while utilizing the electrostatic force. Further, since the recording medium is held on the rotating body via the holding unit, the recording medium can be rotated.

On the other hand, when the rotor plate and the rotating body start to rotate, the gas existing between the rotor plate and the stator plate starts to flow along the dynamic pressure grooves, and the pressure rises. This pressure acts in a direction in which the rotor plate is also separated from the stator plate. That is, the force acts in the thrust direction. When the pressure plate receives this pressure, the stator plate also floats away.

[0020] Further, as described above, since the rotor electrode portion is pulled by the vertical component of the electrostatic force by the applied stator electrode portion, the rotor plate is attracted to the stator plate. Due to the balance between the two, the rotor plate rotates in a state where the stator plate is also separated by a predetermined distance (floating state).

[0021] At the same time, the pressure of the fluid supplied between the rotating body and the shaft also increases, so the fluid dynamic pressure bearing portion supports the force in the radial direction. As a result, the rotating body rotates away from the shaft.

As a result, the rotating body and the rotor plate can smoothly rotate about the rotation axis.

In particular, the fluid dynamic bearing portion is a bearing that uses a fluid such as oil, unlike a mechanical bearing such as a ball bearing. Further, the dynamic pressure groove floats the rotor plate using gas. Therefore, both the rotating body and the rotor plate can be smoothly rotated in a state where vibration is suppressed, and generation of vibration and noise can be suppressed.

[0023] In particular, since the spindle motor according to the present invention includes the dynamic pressure grooves, the rotor electrode portion, and the stator electrode portion, a thrust force can be applied over the entire area of the rotor plate, and a static force can be applied. A tensile force due to electric power can be applied. Therefore, the rotor plate can be stably floated and rotated around the rotation axis, and rotational shake can be suppressed as much as possible. In particular, since the thrust force and the tensile force can be applied even in the vicinity of the outer edge of the rotor plate at a distance from the rotary shaft, the above-described effects are remarkable.

[0024] Further, since the rotor plate rotates stably without rotational vibration or the like, the rotating body can be similarly rotated with rotational vibration suppressed as much as possible. Therefore, it is difficult to generate a radial force. Therefore, even if the length of the shaft is reduced as much as possible, stable rotation can be performed without affecting the rotation of the rotating body and the rotor plate. Therefore, the height of the shaft can be suppressed as much as possible, and the thickness can be reduced.

[0025] In addition, since the rotor plate and the rotating body are rotated using the electrostatic force generated in both electrode portions, unlike the conventional drive mechanism configured with coils and magnets, almost no installation space is required. do not do. From this point as well, the thickness can be reduced.

As described above, according to the spindle motor of the present invention, the recording medium can be rotated stably and with low vibration, and the thickness can be further reduced as compared with the conventional one.

[0027] Further, the spindle motor of the present invention is the spindle motor of the present invention, wherein a protective film is provided on the opposing surface of the rotor plate so as to cover the rotor electrode portion, and the dynamic pressure groove It is provided on the protective film.

[0028] In the spindle motor according to the present invention, since the protective film is formed so as to cover the rotor electrode portion, even if an external force is applied to the rotor plate for some reason during rotation, the protective film is interposed. Therefore, there is no direct contact between the rotor electrode portion and the stator electrode portion. Therefore, mechanical damage of both electrode portions can be prevented, and damage due to discharge can be prevented. Therefore, the quality can be improved and the durability can be increased. Since the dynamic pressure groove is provided on the protective film, the floating of the rotor plate is not affected at all. [0029] Further, the spindle motor of the present invention is the spindle motor of the present invention described above, wherein the opposing surface of the rotor plate and the surface of the stator plate are covered with the rotor electrode portion and the stator electrode portion. A protective film is provided, and the dynamic pressure groove is provided on the protective film.

[0030] In the spindle motor according to the present invention, since the protective film is formed so as to cover the rotor electrode portion and the stator electrode portion, even if an external force is applied to the rotor plate for some reason during the rotation. The rotor electrode portion and the stator electrode portion are not in direct contact with each other. Therefore, mechanical damage of both electrode portions can be prevented, and damage due to discharge can be prevented. Therefore, quality can be improved and durability can be enhanced. Since the dynamic pressure groove is provided on the protective film, there is no influence on the floating of the rotor plate.

[0031] Further, the spindle motor of the present invention is characterized in that, in the spindle motor of the present invention, a protective film is provided on the surface of the stator plate so as to cover the stator electrode portion. Is.

[0032] In the spindle motor according to the present invention, since the protective film is formed so as to cover the stator electrode portion, even if an external force is applied to the rotor plate for some reason during rotation, the protective film is interposed. Therefore, there is no direct contact between the rotor electrode portion and the stator electrode portion. Therefore, mechanical damage of both electrode portions can be prevented, and damage due to discharge can be prevented. Therefore, quality can be improved and durability can be enhanced.

[0033] Further, in the spindle motor of the present invention, in any of the spindle motors of the present invention, the plurality of stator electrode portions are configured such that one of the rotor electrode portions and one of the stator electrode portions are completely. When the opposing positional relationship is established, another stator electrode portion is provided so as to be positioned at least in the vicinity of the fixed direction side of the adjacent rotor electrode portion.

[0034] In the spindle motor according to the present invention, when one of the rotor electrode portions and one of the stator electrode portions are in a completely opposed positional relationship, at least the adjacent rotor electrode portion is in the vicinity of the fixed direction side. The stator electrode portion is always located. That is, the rotor When the electrode part is moved toward the other stator electrode part by electrostatic force, both electrode parts are already approaching and being in a state of being touched.

[0035] In particular, since the magnitude of the electrostatic force is inversely proportional to the distance between the two electrode portions, a larger electrostatic force can be obtained. Therefore, the rotor electrode portion can be moved quickly toward the other stator electrode portion at a higher speed, and the rotor plate can be easily floated by concentrating the pressure in the dynamic pressure groove. Moreover, since a large electrostatic force can be obtained, the rotor plate can be easily pulled toward the stator plate. Therefore, the rotor plate can be rotated with a more stable balance. As a result, the rotation of the recording medium becomes more stable.

[0036] Further, the spindle motor of the present invention is the spindle motor according to any one of the above-described present inventions, wherein the plurality of stator electrode portions each have a width that faces in the circumferential direction. Are arranged so as to be adjacent to each other in close proximity to each other, and the voltage applying means includes substantially the center of the plurality of rotor electrode portions of the plurality of stator electrodes. From the above, the drive voltage is applied to the stator electrode positioned within a range directed in the constant direction by at least 1Z2 of the width of the rotor electrode portion.

[0037] In the spindle motor according to the present invention, the width force in the circumferential direction of each stator electrode portion is formed narrower than the width in the circumferential direction of the rotor electrode portion. For example, it is formed with a width of about 1Z3 than the width of the rotor electrode portion. The stator electrodes having a small width are arranged adjacent to each other in close proximity. In other words, a plurality of status electrode portions are arranged in the circumferential direction around the rotation axis, for example, every 3 to 4 degrees. As a result, no matter where the plurality of rotor electrode portions are located, about three stator electrode portions are always located in a state of facing each rotor electrode portion.

[0038] Then, the voltage applying means is within a range of the plurality of stator electrodes that is oriented in a fixed direction (rotational direction) at least by 1Z2 of the width of the rotor electrode portion from substantially the center of the rotor electrode portion. A drive voltage is applied to the positioned stator electrode. That is, the drive voltage is applied only in the vicinity of the rotor electrode portion and concentrated only on the stator electrode portion that contributes to the movement of the rotor electrode portion. In particular, since the magnitude of the electrostatic force is inversely proportional to the distance between the two electrode portions, a larger electrostatic force can be obtained. Therefore, the rotor electrode portion can be quickly moved at a higher speed, and the rotor plate can be easily floated by concentrating the pressure in the dynamic pressure groove. In addition, since a large electrostatic force can be obtained, the rotor plate is easily pulled toward the stator plate. Therefore, the rotor plate can be rotated with a more stable balance. As a result, the rotation of the recording medium becomes more stable.

[0040] Note that the voltage application means appropriately changes the application to the stator electrode portion as the rotor electrode portion moves so as to maintain the positional relationship described above. In addition, since the width of the stator electrode portion is made as small as possible and the number of stator electrode portions is increased as much as possible, the fluctuation range of the electrostatic force can be reduced. Therefore, the above-described effect can be further enhanced.

[0041] Further, in the spindle motor of the present invention, in any of the spindle motors of the present invention, the shaft is formed in a columnar shape and extends radially outward by a predetermined thickness to expand the diameter. A thrust dynamic pressure groove is formed on the lower surface of the flange portion to support the thrust force in the thrust direction! / It is characterized by scolding.

In the spindle motor according to the present invention, fluid flows along the thrust dynamic pressure groove formed on the lower surface of the flange portion as the rotating body rotates, and the pressure increases. Then, the rotating body receives a pressure generated by the thrust dynamic pressure groove and receives a force in a direction toward the stator plate, that is, a direction opposite to the flying direction, and is pressed. In other words, the fluid dynamic pressure bearing portion can support a thrust force in addition to a radial force. Therefore, the rotating body is pulled to the stator plate side by the electrostatic force acting between the rotor electrode portion and the stator electrode portion and this thrust force during rotation, and the force that rises by the dynamic pressure grooves provided on the rotor plate. Receive. As a result, the rotating body rotates more stably in the thrust direction due to the balance of the three forces. Therefore, it is possible to further reduce vibration and noise during rotation, and to operate the fluid dynamic pressure bearing portion more stably.

[0043] Also, the information recording / reproducing apparatus of the present invention includes the above-mentioned spindle motor of the present invention, a deviation spindle motor, a recording / reproducing head for recording / reproducing information on the recording medium, and the recording / reproducing head. A suspension that supports the recording medium in a floating state, an actuator that supports the base end side of the suspension, and moves the suspension in a direction parallel to the surface of the recording medium; and And a control unit that controls the operation of the recording / reproducing head to perform recording / reproducing.

[0044] In the information recording / reproducing apparatus according to the present invention, after rotating the recording medium in a fixed direction by the spindle motor, the suspension is moved by the actuator, and the recording / reproducing head is placed on the recording medium. Place it in the desired position. At this time, the suspension supports the recording / reproducing head in a state of being levitated by the surface force flying head technology of the recording medium. Thereafter, an instruction is issued by the control unit to operate the recording / reproducing head. As a result, it is possible to record and reproduce various information on the recording medium using the recording and reproducing head.

[0045] In particular, the recording medium can be rotated stably and with low vibration, and the spindle motor that realizes further thinning compared to the conventional one is provided, so that information can be recorded and reproduced accurately. In addition, the thickness can be reduced. Therefore, high quality can be achieved.

Brief Description of Drawings

FIG. 1 is a configuration diagram showing a first embodiment of an information recording / reproducing apparatus having a spindle motor according to the present invention.

2 is a cross-sectional view of the spindle motor shown in FIG.

FIG. 3 is a view of the rotor plate constituting the spindle motor shown in FIG. 2 as viewed from the stator plate side.

4 is a developed sectional view along the circumferential direction of a rotor plate and a stator plate constituting the spindle motor shown in FIG.

FIG. 5 is a view of a dynamic pressure groove constituting the spindle motor shown in FIG. 2 as viewed from the stator plate side.

6 is a view of the stator plate constituting the spindle motor shown in FIG. 2 as viewed from the rotor plate side.

[FIG. 7] A diagram for explaining the movement of the spindle motor shown in FIG. FIG. 7 is a diagram showing a state in which a driving voltage is applied to the data electrode portion and the rotor electrode portion is moved by electrostatic force. (B) is a diagram showing a state in which the rotor electrode portion is moving after the state shown in (a). (C) is a diagram showing a state in which, after the state shown in (b), a driving voltage is applied to a different stator electrode part and the rotor electrode part is started to move again.

FIG. 8 is a diagram showing a spindle motor according to a second embodiment of the present invention, and is a developed sectional view along the circumferential direction of a rotor plate and a stator plate constituting the spindle motor.

FIG. 9 is a view of a stator plate constituting the spindle motor shown in FIG. 8 as viewed from the rotor plate side.

FIG. 10 is a view of the rotor plate constituting the spindle motor shown in FIG. 8 as viewed from the stator plate side.

FIG. 11 is a diagram for explaining the movement of the spindle motor shown in FIG. 8, where (a) shows a state in which a driving voltage is applied to the selected stator electrode portion and the rotor electrode portion is started to move by electrostatic force. FIG. (B) is a diagram showing a state in which, after the state shown in (a), a driving voltage is applied to different stator electrode portions in accordance with the movement of the rotor electrode portion.

FIG. 12 is a view showing a modification example of the spindle motor, and is a cross-sectional development view along the circumferential direction of the rotor plate and the stator plate when a thin protective film is provided on the rotor plate side.

FIG. 13 is a view showing a modified example of the spindle motor, in which the opposite surface of the rotor plate is cut to form a dynamic pressure groove, and the entire remaining protruding portion is used as the rotor electrode portion in the circumferential direction. FIG.

FIG. 14 is a view showing a modified example of the spindle motor, in which the opposite surface of the rotor plate is cut to form a dynamic pressure groove, and a part of the remaining protruding portion is used as the rotor electrode portion in the circumferential direction. FIG.

FIG. 15 is a view showing a modification of the spindle motor, and is a cross-sectional view of the spindle motor including a shaft having a flange portion in which a dynamic pressure groove is formed on the lower surface.

FIG. 16 is a bottom view of the flange portion shown in FIG.

FIG. 17 is a developed sectional view along the circumferential direction of the rotor plate and the stator plate constituting the spindle motor shown in FIG. 2.

BEST MODE FOR CARRYING OUT THE INVENTION [0047] (First embodiment)

A first embodiment of a spindle motor and an information recording / reproducing apparatus according to the present invention will be described below with reference to FIGS. Note that FIG. 4 shows a developed state of a cross section along the circumferential direction.

As shown in FIG. 1, the information recording / reproducing apparatus 1 of the present embodiment includes various information on a spindle motor 2 and a magnetic disk D (hereinafter simply referred to as disk D) (disc-shaped recording medium). A magnetic head (recording / reproducing head) 3, a suspension 4 for supporting the magnetic head in a state where it floats from the surface of the disk D, a base end side of the suspension 4, and the suspension Actuator 5 that scans 4 in the XY direction parallel to the surface of disk D, control unit 6 that controls the operation of magnetic head 3 to perform recording and reproduction, and control unit 6 and magnetic head 3 includes a cord portion 7 that connects to the housing 3, and a housing 8 that accommodates these components.

[0049] The sawing 8 is made of a metal material such as aluminum in a square shape when viewed from above, and has a recess 8a for accommodating each component inside. Further, a lid (not shown) is detachably fixed to the housing 8 so as to close the opening of the recess 8a. The spindle motor 2 is attached to substantially the center of the recess 8a, and the disc D is detachably fixed by fitting a center hole into a hub 20 (to be described later) of the spindle motor 2.

In addition, the actuator motor 5 is attached to the corner of the recess 8a. A carriage 10 is attached to the actuator motor 5 via a bearing 9, and a suspension 4 is attached to the tip of the carriage 10. The carriage 10 and the suspension 4 are both movable in the XY directions by driving the actuator motor 5.

It should be noted that the carriage 10 and the suspension 4 are also configured to retract the force on the disk D by driving the actuator motor 5 when the rotation of the disk D is stopped. The optical signal controller 7 is mounted in the recess 8 a so as to be adjacent to the actuator motor 5.

[0052] The magnetic head 3 has a coil unit (not shown). When the information is recorded in response to these instructions, the information is output as a magnetic signal and recorded on the disk D. Further, when performing reproduction, the magnetic signal output from the disk D is read by the coil unit and sent to the control unit 14. As a result, various kinds of information can be recorded and reproduced on the disc D.

The spindle motor 2 is a motor that drives the disk D to rotate around the rotation axis L. As shown in FIG. 2, the spindle 15 is disposed along the rotation axis L, and the shaft 15 While supporting the base end side, with a certain clearance from the shaft 15 and the stator plate 16 disposed along the plane perpendicular to the rotation axis L (horizontal plane along the XY direction) and the shaft 15 The rotating body 17 which is inserted and can be rotated around the rotation axis L and has a step portion (holding portion) 20a for holding the disk D on the outer peripheral surface, and conductive oil (fluid) supplied to the gap. W has a fluid dynamic pressure bearing portion 18 that supports at least the radial force when the rotating body 17 rotates, and a facing surface 19a that faces the stator plate 16, and is located on the base end side of the rotating body 17. And a rotor plate 19 which is fixed and rotates together.

In the present embodiment, it is assumed that the stator plate 16 also serves as the bottom plate of the housing 8 as shown in FIG. However, the present invention is not limited to this, and a stator plate may be attached on the bottom plate of the housing 8.

As shown in FIG. 2, the shaft 15 is formed in a cylindrical shape, and is erected on the stator plate 16 at a substantially central position of the housing 8. Further, as shown in FIG. 2, a V-shaped dynamic pressure groove 15a is formed on the outer peripheral surface of the shaft 15 by joining the linear grooves at the junction 15b. At this time, the dynamic pressure groove 15a is formed with the V-shaped sideways so that when the rotating body 17 rotates, the confluence 15b is added later and rotated in such a manner as to be applied, The As a result, when the rotating body 17 rotates, the oil W flows in the direction opposite to the rotation direction along the dynamic pressure groove 15a. That is, the dynamic pressure groove 15a functions as a radial bearing portion that supports a radial force. The dynamic pressure groove 15a and the oil W constitute the fluid dynamic pressure bearing portion 18 described above.

The rotating body 17 is composed of a hub 20 formed in a cup shape and a cylindrical sleeve 21 fitted and fixed in the hub 20. That is, the rotating body 17 is attached to the shaft 15 with a gap between the sleeve 21 and the shaft 15. And Sha Oil W is supplied between the foot 15 and the sleeve 21 and is full. Further, the step portion 20 a is formed on the outer peripheral surface of the hub 20. Thus, when the disk D is fitted in the hub 20, the disk D is held in contact with the stepped portion 20a.

The rotor plate 19 is formed in a disk shape having substantially the same size as the disk D, and is fixed in contact with the lower portion of the hub 20 and the outer peripheral surface of the sleeve 21. The size of the rotor plate 19 is not limited to the case described above, and may be larger or smaller than the disk D. In addition, a seal (not shown) is provided between the rotor plate 19 and the sleeve 21 so that the oil W supplied between the shaft 15 and the sleeve 21 does not flow into the rotor plate 19 side. Become! /

Further, as shown in FIGS. 3 and 4, the opposing surface 19a of the rotor plate 19 has a predetermined angle Θ 1 in the circumferential direction centered on the rotation axis L, that is, plural at every 30 degrees. An arranged fan-shaped rotor electrode portion 25 is provided. In the present embodiment, a plurality of rotor electrode portions 25 are formed on the opposing surface 19a of the rotor plate 19 by adhesion, vapor deposition, or the like. The plurality of rotor electrode portions 25 are grounded in advance via the rotor plate 19, the sleeve 21, the oil W, and the stator plate 16.

Further, a protective film 22 is provided on the opposing surface 19 a of the rotor plate 19 so as to cover the plurality of rotor electrode portions 25. A plurality of dynamic pressure grooves 23 are provided on the protective film 22 to generate pressure in a direction in which the rotor plate 19 is separated from the stator plate 16 as the rotor plate 19 rotates.

[0060] As shown in FIGS. 4 and 5, the dynamic pressure groove 23 is carved so as to bend toward the center from the outer edge. That is, the plurality of dynamic pressure grooves 23 have a windmill shape as a whole. As a result, when the rotor plate 19 rotates, the gas existing between the rotor plate 19 and the stator plate 16 flows along the dynamic pressure groove 23, and flows toward the center.

Further, as shown in FIGS. 4 and 6, the stator plate 16 has the predetermined angle 0 toward the circumferential direction centered on the rotation axis L in a circular region facing the rotor plate 19. An angle Θ2 narrower than 1 (30 degrees), for example, a plurality of fan-shaped stator electrode portions 26 are provided every 20 degrees. In the present embodiment, as shown in FIG. 4, the circumferential direction of the rotor electrode portion 25 The stator electrode portion 26 is formed so that the width Wl of the stator and the width W2 of the stator electrode portion 26 are the same size.

[0062] Further, due to the arrangement relationship between the two electrode portions 25 and 26 described above, the stator electrode portion 26 is always positioned between the adjacent rotor electrode portions 25. Furthermore, when one of the rotor electrode portions 25 and one of the stator electrode portions 26 are in a completely opposite positional relationship, at least near the fixed direction (rotation direction) side of the adjacent rotor electrode portion 25, the other The stator electrode part 26 is always positioned. That is, in the present embodiment, the interval (pitch) between the rotor electrode portions 25 is 1.5 times the interval (pitch) between the stator electrode portions 26.

Further, similarly to the rotor plate 19, a protective film 24 is provided on the surface of the stator plate 16 so as to cover the plurality of stator electrode portions 26. In addition, the plurality of stator electrode portions 26 are not shown as shown in FIG. The voltage application unit (voltage application means) 27 is electrically connected via a wiring. The voltage application unit 27 applies a drive voltage for a predetermined time only to the selected stator electrode unit 26 among the plurality of stator electrode units 26. By repeatedly applying this voltage, The rotor plate 19 is rotated in a certain direction using electrostatic force. This will be described in detail later.

[0064] Next, a case where various types of information is recorded on and reproduced from the disc D by the information recording and reproducing apparatus 1 configured as described above will be described below.

First, the voltage application unit 27 applies a drive voltage to the selected stator electrode unit 26 among the plurality of stator electrode units 26 for a predetermined time. Specifically, as shown in FIG. 7 (a), the drive voltage is applied to the stator electrode portion 26 (Sl, S4 position) located on the fixed direction (rotational direction) side of the rotor electrode portion 25. In FIG. 7, illustration of both protective films 22 and 24 is omitted.

[0066] At this time, since the plurality of rotor electrode portions 25 are all grounded in advance, a positive voltage and a negative voltage are applied to the applied status electrode portion 26 and rotor electrode portion 25, respectively. It will be added. As a result, positive and negative charges are induced on the surfaces of the electrode portions 25 and 26, respectively, and an electrostatic force (electrostatic attractive force) F that attracts them is generated.

[0067] Then, due to the horizontal component of the electrostatic force F, the rotor electrode portion 25 is shown in FIG. Thus, it gradually moves toward the applied stator electrode part 26 (SI, S4 position). Then, as shown in FIG. 7 (c), the rotor electrode portion 25 moves to a position completely opposite to the applied stator electrode portion 26, and at the same time, the voltage applying portion 27 is applied to the stator electrode portion 26. While stopping the application, the drive voltage is applied to the next stator electrode portion 26 (S3 position) located on the fixed direction (rotational direction) side of the rotor electrode portion 25 that has started to move. As a result, the above-described operation is repeated, and the rotor electrode portion 25 moves again.

As a result, the rotor plate 19 and the rotating body 17 can be rotated about the rotation axis L in a certain direction while using the electrostatic force F. Further, since the disk 20 is held by the step portion 20a in the hub 20, the disk D can be rotated via the rotating body 17.

On the other hand, when the rotor plate 19 and the rotating body 17 start to rotate, the gas existing between the rotor plate 19 and the stator plate 16 starts to flow along the dynamic pressure groove 23 and the pressure increases. This pressure acts in a direction in which the rotor plate 19 is separated from the stator plate 16. In other words, the force acts in the thrust direction. Under this pressure, the rotor plate 19 floats away from the stator plate 16. Further, as described above, the rotor electrode portion 25 is pulled by the vertical component of the electrostatic force by the applied stator electrode portion 26, so that the rotor plate 19 is attracted to the stator plate 16. Due to the balance between the two, the rotor plate 19 rotates with the stator plate force separated by a predetermined distance G (floating state) as shown in FIG.

[0070] At the same time, the oil W supplied to the gap between the shaft 15 and the sleeve 21 starts flowing in the direction opposite to the rotation direction along the dynamic pressure groove 15a. The oil W flowing along the dynamic pressure groove 15a has the highest pressure at the junction 15b. As a result, the sleeve 21 is supported at the radial kaka point and is rotated away from the shaft 15. In other words, the fluid dynamic pressure bearing portion 18 supports the radial force generated during rotation.

Due to the interaction between the dynamic pressure groove 23 and the fluid dynamic pressure bearing portion 18 described above, the rotating body 17 and the rotor plate can smoothly rotate about the rotation axis L. In particular, the fluid dynamic pressure bearing portion 18 is a bearing using oil W unlike a mechanical bearing such as a ball bearing. Further, the dynamic pressure groove 23 floats the rotor plate 19 using gas. Therefore, the rotating body 17 and The rotor plate 19 can be smoothly rotated with both vibrations suppressed, and the occurrence of vibration and sound loss can be suppressed.

As described above, after the disk D is rotated by the spindle motor 2, the actuator 5 is operated to scan the suspension 4 in the XY directions via the carriage 10 as shown in FIG. As a result, the magnetic head 3 can be positioned at a desired position on the disk D. Next, the magnetic head 3 is operated by the control unit 6. In response to this, the magnetic head 3 outputs the information to be recorded as a magnetic signal and performs recording on the disk D or reads and reproduces the magnetic signal output from the disk. As a result, the magnetic head 3 can be used to record and reproduce various types of information on the disk D.

[0073] In particular, the spindle motor 2 of the present embodiment includes the dynamic pressure groove 23, the rotor electrode portion 25, and the stator electrode portion 26, so that a thrust force is applied over the entire area of the rotor plate 19. In addition, a tensile force (vertical component of electrostatic force F) can be applied. Therefore, the rotor plate 19 can be stably floated and rotated around the rotation axis L, and rotational shake can be suppressed as much as possible. In particular, since the thrust force and the tensile force can be applied even in the vicinity of the outer edge of the rotor plate 19 that is separated from the rotation axis L, the above-described effects are remarkable.

[0074] Further, since the rotor plate 19 rotates stably with no rotational vibration or the like, the rotating body 17 can be rotated with the rotational vibration suppressed as much as possible. Therefore, it is difficult for radial force to be generated. Therefore, even if the length of the shaft 15 is made as low as possible, stable rotation can be performed without affecting the rotation of the rotating body 17 and the rotor plate 19. Therefore, as shown in FIG. 2, the height of the shaft 15 can be suppressed as much as possible, and the thickness can be reduced.

[0075] In addition, since the rotor plate 19 and the rotating body 17 are rotated using the electrostatic force F generated in both electrode portions 26, 26, unlike the conventional drive mechanism configured with coils and magnets, etc. Requires little space. From this point as well, the thickness can be reduced.

[0076] As described above, according to the spindle motor 2 of the present embodiment, the disk D can be rotated stably and with low vibration, and the thickness can be further reduced as compared with the conventional one. The

[0077] Further, according to the information recording / reproducing apparatus 1 of the present embodiment, since the spindle motor 2 is provided, information can be recorded / reproduced accurately and the thickness can be reduced. Therefore, high quality can be achieved. Moreover, since it is also a spindle motor 2 with low vibration and low noise, this point force can also achieve high quality and improve product reliability.

Furthermore, the spindle motor 2 of the present embodiment can continuously and smoothly rotate the rotor electrode part 25 grounded in advance by applying a voltage to the selected stator electrode part 26 one after another. it can. Therefore, the disk D can be continuously and stably rotated at a uniform speed.

In this embodiment, as shown in FIG. 7A, the spacing (pitch) between the rotor electrode portions 25 is 1.5 times the spacing (pitch) between the stator electrode portions 26 in this embodiment. Therefore, when one of the rotor electrode parts 25 (R2 position) and one of the stator electrode parts 26 (S2 position) are in a completely opposed position, at least the adjacent rotor electrode part 25 (R3 position) The other stator electrode part 26 (S4 position) is always located near the fixed direction side of. That is, when the mouth electrode portion 25 is moved toward the other stator electrode portion 26 by the electrostatic force F, both the electrode portions 25 and 26 are already close to each other. In particular, since the magnitude of the electrostatic force F is inversely proportional to the distance between the electrode portions 25 and 26, a larger electrostatic force can be obtained.

Accordingly, the rotor electrode portion 25 can be moved quickly at a higher speed toward the other stator electrode portion 26, and the rotor plate 19 can be easily floated by concentrating the pressure in the dynamic pressure groove 23. Can be raised. In addition, since a large electrostatic force F can be obtained, the rotor plate 19 can be easily pulled toward the stator plate 16 side. Therefore, the rotor plate 19 can be rotated with a more stable balance. As a result, the rotation of the disk D becomes more stable.

Further, since the protective films 22 and 24 are formed so as to cover the rotor electrode portion 25 and the stator electrode portion 26, respectively, even if an external force is applied to the rotor plate 19 for some reason during rotation, the rotor is directly The electrode part 25 and the stator electrode part 26 do not come into contact with each other. Therefore, mechanical damage to both electrode portions 25 and 26 can be prevented, and damage due to discharge can be prevented. Therefore, quality can be further improved and durability can be improved. Can be increased.

(Second embodiment)

Next, a second embodiment of the spindle motor according to the present invention will be described with reference to FIGS. Note that the same reference numerals in the second embodiment denote the same parts as in the first embodiment, and a description thereof will be omitted. Further, FIG. 8 illustrates a state in which a cross section along the circumferential direction is developed.

The difference between the second embodiment and the first embodiment is that, in the first embodiment, the width W1 that faces the circumferential direction of the rotor electrode part 25 and the circumferential direction of the stator electrode part 26 are directed. Whereas the width W2 is the same size, in the spindle motor 30 of the second embodiment, the stator electrode portion 31 is formed such that the circumferential width W3 is smaller than the width W1 of the rotor electrode portion 32. In addition, it is arranged in a narrow state in the circumferential direction and densely arranged at a pitch.

Further, in the first embodiment, the dynamic pressure groove 23 is provided on the protective film 22, whereas in the second embodiment, the rotor electrode portion 32 is adjacent to the opposing surface 19a of the rotor plate 19. Thus, the dynamic pressure groove 23 is formed. Therefore, unlike the first embodiment in which the rotor electrode portion 32 and the stator electrode portion 31 of the second embodiment are formed in a fan shape, the rotor electrode portion 32 and the stator electrode portion 31 are each directed toward the center from the outer edge according to the shape of the dynamic pressure groove 23. It is formed so as to be curved, and is formed as a windmill as a whole.

That is, in the spindle motor 30 of the present embodiment, as shown in FIGS. 8 and 9, the width W3 of each stator electrode portion 31 is formed to be about 1Z3 wider than the width W1 of the rotor electrode portion 32. ing. The stator electrode portions 31 having a small width are arranged so as to be adjacent to each other in close proximity. That is, the plurality of stator electrode portions 31 are arranged in the circumferential direction around the rotation axis L, for example, at every angle Θ3 of 3 to 4 degrees. As a result, no matter where the plurality of rotor electrode portions 32 are located, about three stator electrode portions 31 are necessarily located in a state of being opposed to each rotor electrode portion 32.

Further, the rotor electrode portion 32 of the present embodiment is configured integrally with the rotor plate 19 as shown in FIGS. That is, the rotor plate 19 is formed of a material having conductivity, and the dynamic pressure groove 23 is formed by cutting a predetermined position of the facing surface 19a. As a result, it is possible to use the entire portion (projected portion) that is cut and V ヽ as the rotor electrode portion 32 as it is. it can.

Further, a protective film 33 is provided on the surface of the stator plate 16 of the present embodiment so as to cover the plurality of stator electrode portions 31.

When the spindle motor 40 configured in this way is operated, as shown in FIG. 11 (illustration of the protective film 233 is omitted), the voltage application unit 27 includes a plurality of stator electrode units 31. Among them, the stator electrode part 31 is located within a range (Al, A2, A3 area) from the approximate center of the rotor electrode part 32 toward the constant direction (rotation direction) by 1Z2 of the width of the rotor electrode part 32. A drive voltage is applied to.

That is, the drive voltage is applied in a concentrated manner only to the stator electrode portion 31 that is close to the rotor electrode portion 32 and contributes to the movement of the rotor electrode portion 32. In particular, since the magnitude of the electrostatic force F is inversely proportional to the distance between the electrode portions 31 and 32, a larger electrostatic force F can be obtained. Therefore, the rotor electrode portion 32 can be quickly moved at a higher speed, and the rotor plate 19 can be easily floated by concentrating the pressure in the dynamic pressure groove 23. Further, since a large electrostatic force F can be obtained, the rotor plate 19 is easily pulled toward the stator plate 16 side. Therefore, the rotor plate 19 can be rotated with a more stable balance.

[0089] Further, since the stator electrode portion 31 having a narrow circumferential width W3 is arranged in a close proximity, all the rotor electrode portions 32 (Rl, R2, and R3 positions) must be continuously moved at the same time. Can do. Therefore, the disk D can be rotated in a more stable state.

Note that the voltage application unit 27 sequentially changes the application to the stator electrode unit 31 as the rotor electrode unit 32 moves so as to maintain the above-described positional relationship. Further, since the width W3 of the stator electrode portion 31 is made as narrow as possible and the number of the stator electrode portions 31 is increased, the fluctuation range of the electrostatic force F can be reduced. Therefore, the above-described effect can be further enhanced.

Further, since the protective film 33 is provided so as to cover the stator electrode portion 31, the rotor plate 19 and the stator plate 16 do not come into direct contact as in the first embodiment. Therefore, mechanical damage to both electrode portions 31 and 32 can be prevented, and damage due to discharge can be prevented. Therefore, quality can be improved and durability can be further enhanced. It should be noted that the technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

For example, in the first embodiment, the protective film 22 is formed thicker so that the bottom of the dynamic pressure groove 23 is positioned closer to the stator plate 16 than the surface of the rotor electrode 25. For example, as shown in FIG. 12, the protective film 22 is provided at substantially the same height as the rotor electrode 25, and the dynamic pressure groove 23 is positioned so that the bottom of the groove 23 is located near the surface of the facing surface 19b. May be provided between the aperture electrode portions 25. Even in this case, the same effect as the first embodiment can be obtained. However, it is more preferable because the thickness of the protective film 22 can be made as thin as possible.

In this case, the rotor electrode portion 25 may be formed in the same shape as the dynamic pressure groove 23 as in the second embodiment.

In the first embodiment, the protective film 24 on the rotor plate 19 side is eliminated, and the dynamic pressure groove 23 is formed on the opposing surface 19a of the rotor plate 19 as in the second embodiment as shown in FIG. You may provide. At this time, as shown in FIG. 13, all of the protruding portions other than the dynamic pressure groove 23 may be the rotor electrode portion 25, and as shown in FIG. 14, a part of the protruding portion is the rotor electrode portion 25. You can use it.

[0096] Further, in each of the above embodiments, the dynamic pressure groove is provided around the shaft, and the fluid dynamic pressure bearing portion is configured to support only the radial force. For example, the shaft is not limited to this. A dynamic pressure groove may be provided on the upper surface of the sleeve or the lower surface of the sleeve to support the thrust force in addition to the radial force.

Further, as shown in FIG. 15, the flange portion 40 is formed on the shaft 15, and the dynamic pressure groove (thrust dynamic pressure groove) 40 a shown in FIG. 16 is formed on the lower surface of the flange portion 40. Ok.

As shown in FIG. 15, the flange portion 40 extends from the outer peripheral surface of the shaft 15 to the outside in the radial direction by a predetermined thickness and is formed in a bowl shape by expanding the diameter. In FIG. 15, a case where the flange portion 40 is formed on the upper surface of the shaft 15 is taken as an example. However, the present invention is not limited to this case. For example, the flange portion 40 may be formed near the middle of the shaft 15. FIG. 15 shows an example in which the dynamic pressure grooves 15a formed on the outer peripheral surface of the shaft 15 are formed in two upper and lower stages. However, the present invention is not limited to this, and may be one stage, or divided into three or more stages. It may be formed. Further, the two dynamic pressure grooves 15a may be formed in a separated state.

[0099] As shown in FIG. 16, a plurality of the dynamic pressure grooves 40a curved from the outer edge toward the rotation axis L are formed on the lower surface of the flange portion 40. That is, the plurality of dynamic pressure grooves 40a have a windmill shape as a whole. As a result, when the rotating body 17 rotates, the oil W flows toward the center along the dynamic pressure groove 40a. That is, the dynamic pressure groove 40a functions as a thrust bearing portion that supports a thrust force.

[0100] When the flange portion 40 having the dynamic pressure groove 40a formed on the lower surface is provided as described above, the oil W begins to flow along the dynamic pressure grooves 15a and 40a when the rotating body 17 starts to rotate. As the pressure increases, the gas begins to flow along the dynamic pressure groove 23 and the pressure increases. At this time, the oil W flowing along the dynamic pressure groove 15a has the highest pressure at the junction 15b. Therefore, the sleeve 21 constituting the rotating body 17 is in a state where the radial force is supported at two points, and is rotated away from the shaft 15. As a result, the rotator 17 can be stably rotated without any lateral shaking.

On the other hand, the rotor plate 19 floats away from the stator plate 16 due to the gas flowing along the dynamic pressure groove 23. At the same time, the pressure of the oil W flowing along the dynamic pressure groove 40a formed on the lower surface of the flange portion 40 increases on the side close to the rotation axis L. However, the pressure generated in the dynamic pressure groove 4 Oa is generated on the lower surface side of the flange portion 40 formed on the fixed shaft 15. Therefore, the rotating body 17 receives the pressure and receives a force in the direction of the stator plate 16, that is, in the direction opposite to the direction of rising, and is pressed. That is, the fluid dynamic pressure bearing portion 18 in this case can support the thrust force.

[0102] In this way, the rotating body 17 rotates while simultaneously receiving the rising force and the pressing force. Further, since the rotating body 17 is also simultaneously affected by the electrostatic force F acting between the rotor electrode portion 25 and the stator electrode portion 26, the rotating body 17 is pulled toward the stator plate 16 by the electrostatic force F.

That is, the rotating body 17 and the rotor plate 19 rotate in a more stable state with respect to the thrust direction by the balance of these three forces. In particular, since the rotating body 17 and the rotor plate 19 can be pressed using the thrust force generated only by the electrostatic force F, the rotation is further stabilized. As a result, it is possible to further reduce vibration and sound loss during rotation and The body dynamic pressure bearing portion 18 can be operated more stably.

[0104] Further, as an example of the recording / reproducing head, the head is not limited to the magnetic head described by taking the magnetic head as an example. Absent. For example, a near-field optical head that performs recording / reproduction using near-field light may be used as the recording / reproducing head.

[0105] It should be noted that each of the stator electrode portions 26 described above is of course disposed at every angle narrower than the predetermined angle θ1, and is not limited to this. As shown in FIG. 17, each of the state electrode portions 26 may be arranged at every predetermined angle Θ4 wider than the predetermined angle θ1.

Thus, even when the spacing force of the stator electrode 26 is wider than the spacing of the rotor electrode portion 25, the rotor electrode portion 25 is pulled and rotated by the electrostatic force F of the stator electrode portion 26. By switching the voltage application to the stator electrode part 26, the rotation of the rotating body 17 is maintained.

According to the powerful feature, the number of stator electrode portions 26 can be reduced as compared with that in FIG. 7 by arranging each of the stator electrode portions 26 for each predetermined angle Θ 4. Cost can be reduced.

Industrial applicability

[0108] According to the spindle motor of the present invention, the recording medium can be rotated stably and with low vibration, and the thickness can be further reduced as compared with the conventional one.

[0109] Further, according to the information recording / reproducing apparatus of the present invention, since the spindle motor is provided, the information recording / reproducing can be performed accurately and the thickness can be reduced. Therefore, high quality can be achieved.

Claims

The scope of the claims

[1] A spindle motor that rotates a disk-shaped recording medium capable of recording various kinds of information around a rotation axis,

A shaft disposed along the rotation axis;

A stator plate that supports a base end side of the shaft and is disposed along a plane perpendicular to the rotation axis;

A rotating body that is inserted into the shaft with a certain gap therebetween and can be rotated around the rotation axis, and has a holding portion for holding the recording medium on an outer peripheral surface, and is supplied to the gap A fluid dynamic bearing having at least a radial force when the rotating body rotates;

A rotor plate having a facing surface facing the stator plate, fixed to the base end side of the rotating body, and rotating together;

A plurality of rotor electrode portions that are provided on opposite surfaces of the rotor plate and arranged at predetermined angles in a circumferential direction around the rotation axis;

A plurality of stator electrode portions provided on a surface of the stator plate and arranged in a circumferential direction around the rotation axis;

Voltage applying means for applying a driving voltage to a selected stator electrode portion of the plurality of stator electrode portions for a predetermined time and rotating the rotor plate in a certain direction by electrostatic force;

A dynamic pressure groove provided on an opposing surface of the rotor plate and generating pressure in a direction of separating the stator plate force with the rotation of the rotor plate;

The spindle motor, wherein the plurality of rotor electrode portions are grounded via at least the rotor plate and the fluid.

[2] In the spindle motor according to claim 1,

Each of the stator electrode portions is arranged at an angle narrower than the predetermined angle.

[3] In the spindle motor according to claim 1,

On the facing surface of the rotor plate, a protective film is provided so as to cover the rotor electrode portion, The spindle motor, wherein the dynamic pressure groove is provided on the protective film.

[4] In the spindle motor according to claim 1,

A protective film is provided on the opposite surface of the rotor plate and the surface of the stator plate so as to cover the rotor electrode portion and the stator electrode portion,

The spindle motor, wherein the dynamic pressure groove is provided on the protective film.

[5] In the spindle motor according to claim 1,

A spindle motor, wherein a surface of the stator plate is provided with a protective film V so as to cover the stator electrode portion.

[6] The spindle motor as set forth in any one of claims 1 and 2, wherein

When the plurality of stator electrode portions are in a positional relationship in which one of the rotor electrode portions and one of the stator electrode portions are completely opposed to each other, at least the adjacent rotor electrode portions are located in the vicinity of the fixed direction side. The spindle motor is characterized in that it is provided so that the stator electrode portion of the motor is located.

[7] The spindle motor as set forth in any one of claims 1 to 5,

Each of the plurality of stator electrode portions is formed so that a width directed in the circumferential direction is narrower than a width of each of the plurality of rotor electrode portions, and is arranged adjacent to each other in a close state. ,

The voltage applying means is a stator electrode located within a range of the plurality of stator electrodes that is oriented in the constant direction by at least 1Z2 of the width of the rotor electrode portion from substantially the center of the plurality of rotor electrode portions. A spindle motor, wherein the drive voltage is applied to the unit.

[8] In the spindle motor according to claim 1,

The shaft is formed in a columnar shape, and has a flange-like flange portion on the outer peripheral surface that extends radially outward by a predetermined thickness and expands in diameter.

The spindle motor according to claim 1, wherein the fluid dynamic pressure bearing portion includes a thrust dynamic pressure groove formed on a lower surface of the flange portion and supporting a thrust force in the thrust direction.

[9] The spindle motor according to any one of claims 1 to 5, 7, and 8, the recording / reproducing head for recording / reproducing information on the recording medium,

A suspension for supporting the recording / reproducing head in a state of floating from the surface of the recording medium;

An actuator for supporting the base end side of the suspension and moving the suspension in a direction parallel to the surface of the recording medium;

An information recording / reproducing apparatus comprising: a control unit that controls the operation of the recording / reproducing head to perform recording / reproducing.

[10] The spindle motor according to claim 6,

A recording / reproducing head for recording / reproducing information on the recording medium;