WO2007094112A1

WO2007094112A1 - Spindle motor and information recording/reproducing device

Info

Publication number: WO2007094112A1
Application number: PCT/JP2006/324147
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: JPWO2007094112A1

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 the prescribed angle (θ1); and 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. 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. For example, a PM (Permanent Magnet) motor using a permanent magnet is known.

[0003] However, with the recent miniaturization of electronic devices, the size of the disk itself is becoming smaller. For example, discs with diameters of lin and 0.85in have been developed and are beginning to be used in high-performance digital cameras and small portable music players. In addition, along with the downsizing of electronic devices and disks, motors that drive disks are required to be further reduced in size and thickness in the future.

[0004] Therefore, as a motor that is smaller and thinner than the PM motor described above, an electrostatic drive motor that rotates a disk using electrostatic force is known.

[0005] For example, as one of them, a stator having a plurality of electrode patterns in the circumferential direction and the radial direction, and a dielectric tooth butter which is rotatably arranged with respect to the stator and is made of dielectric teeth. There are known electrostatic stepping motors having a rotor provided with a radial shape (see, for example, Japanese Patent No. 3354009).

[0006] When the electrostatic stepping motor is operated, control is performed so that a voltage is applied to one selected electrode pattern among a plurality of electrode patterns provided on the stator. In response to this, the dielectric tooth pattern provided on the rotor appears in a state where positive and negative charges are alternately switched on the surface facing the electrode pattern side.

[0007] Thereby, for example, the dielectric tooth pattern that has been attracted to the electrode pattern by electrostatic attraction force. The turn is separated from the electrode pattern cover by receiving electrostatic repulsion due to the exchange of electric charges. Then, the separated dielectric tooth pattern moves by receiving the electrostatic attraction force of the adjacent electrode pattern cover, and stops by adsorbing to the electrode pattern. In this state, by applying voltage to each electrode again, the charge of the dielectric tooth pattern can be exchanged, and the above operation is repeated to move the dielectric tooth pattern that has been attracted again. Is possible.

As a result, the rotor rotates while repeating a temporary stop at every predetermined angle. In other words, the rotor can be rotated while performing a stepping operation at every predetermined angle. In addition, the disk rotates as the rotor rotates.

[0009] Further, as another electrostatic drive type motor, a disk having one or both surfaces made of a high-resistance substrate, and a plurality of disks are driven on the surface facing the high-resistance substrate while rotating the disk. There is known a disk rotation driving device having a rotation driving electrode plate in which the dot electrodes are arranged concentrically (see, for example, Japanese Patent No. 3725986).

[0010] When the rotary drive device is operated, a voltage is applied to each of the plurality of dot electrodes to form a rotating electric field centered on the concentricity of the electrode pattern. This rotating electric field then induces charges on the surface of the high resistance substrate of the disk. Here, since a high-resistance substrate such as a glass substrate is a high-resistance body, a phase lag occurs between the induced charge and the voltage applied to the voltage, and rotational torque is applied to the high-resistance substrate. appear. As a result, the disk can be rotated. In this apparatus, the disk itself serves as a rotor constituting a general motor.

[0011] As described above, any device (electrostatic drive type motor) does not require a permanent magnet, a coil, or the like unlike a PM motor, and thus can be easily reduced in size and thickness. Therefore, application to recent electronic devices aiming at miniaturization is beginning to be considered.

Disclosure of the invention

[0012] However, the conventional apparatus described above still has the following problems.

That is, the apparatus described in Patent Document 1 rotates the rotor by alternately switching the charge appearing on the surface of the dielectric tooth pattern provided on the rotor between plus and minus. ing. For this reason, it can only be rotated by a stepping operation that temporarily rotates the rotor. I couldn't turn it. For this reason, it was difficult to rotate the disk continuously and smoothly.

[0014] Further, every time the rotor is temporarily stopped, the dielectric tooth pattern and the electrode pattern come into contact with each other, so that there is a possibility that both of them are damaged and wear easily. As a result, vibration and noise are likely to occur and the durability is reduced. Furthermore, there is a possibility that dust or the like may be generated due to the contact, and there is a possibility that the cleanliness of the equipment in which the rotor is mounted, for example, the information recording / reproducing apparatus cannot be kept constant.

[0015] Further, since the dielectric is used, when the switching of the voltage application to the electrode pattern is made faster, the switching of the electric charge cannot catch up and the rotation may be irregular. .

[0016] In addition, unlike the general motor, the device described in Patent Document 2 is such that the disk itself also serves as a rotor. For this reason, it was difficult to use the dedicated disk and power.

[0017] In addition, a normal disk is manufactured according to a predetermined standard and does not have high rigidity with a small thickness. For this reason, in this apparatus that uses the disk like a rotor, there is a risk of the disk becoming distorted and deformed. Therefore, the gap between the disk and the electrode plate for rotation drive cannot be kept uniform in the plane.

[0018] As a result, there is a possibility that the disk and the electrode plate for rotation drive come into contact with each other during the rotation of the disk. Further, on the disk, the head force for recording / reproducing information on the disk is placed in a state of being floated by the flying head technology. However, there is a possibility that the disk may interfere with this head part. there were. As a result, various data recorded on the disc may be adversely affected, and each component may be adversely affected by contact, resulting in poor reliability.

The present invention has been made in view of such circumstances, and its purpose is to continuously and smoothly rotate a recording medium through a rotor plate while preventing damage and wear due to contact. It is also possible to provide a spindle motor and an information recording / reproducing apparatus having the spindle motor that can improve reliability by reducing vibration, noise, and durability.

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 kinds of information around a rotation axis, and is a shaft arranged along the rotation axis. And a stator plate that supports the base end side of the shaft and that is disposed along a plane perpendicular to the rotation axis, and is inserted with a certain clearance from the shaft, and the rotation A rotating body that is rotatable about an axis and has a holding portion for holding the recording medium on an outer peripheral surface, and a conductive fluid supplied to the gap, and a thrust when the rotating body rotates A hydrodynamic pressure bearing portion that supports a radial force and a radial force, 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, and the rotor Provided on the opposite surface of the plate, A plurality of rotor electrode portions arranged at a predetermined angle in the circumferential direction and a plurality of rotor electrode portions provided on the surface of the stator plate at a narrower angle than the predetermined angle in the circumferential direction around the rotation axis. A driving voltage is applied to the selected stator electrode portion for a predetermined time among the arranged stator electrode portions and a plurality of stator electrode portions!], And the rotor plate is fixed in a certain direction by electrostatic force. And a plurality of rotor electrode portions that are grounded through at least the rotor plate and the fluid.

[0022] In the spindle motor according to the present invention, first, the rotating body is inserted and attached to the shaft supported at the base end side by the 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.

[0023] In addition, a plurality of rotor electrode portions are provided on the opposing surface of the rotor plate at predetermined angles (for example, every 30 degrees) in the circumferential direction around the rotation axis. Further, on the surface of the stator plate, a plurality of stator electrode portions are provided for each angle (for example, every 20 degrees) narrower than the predetermined angle in the 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.

[0024] Here, the stator electrode selected from the plurality of stator electrode portions by the voltage applying means. A drive voltage is applied to the part for a predetermined time. Specifically, the drive voltage is applied to the stator electrode portion located on the rotation direction (constant direction) side of the rotor electrode portion. At this time, since the plurality of rotor electrode portions are grounded in advance via at least the rotor electrode portion and the conductive fluid, a positive voltage and a negative voltage are respectively applied to the applied stator electrode portion and the rotor electrode portion. Is applied. 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.

[0025] 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.

[0027] On the other hand, when the rotating body and the rotor plate start to rotate, the pressure of the fluid supplied between the rotating body and the shaft increases. As a result, the rotating body moves away from the shaft and the stator plate force also rises. In other words, the rotating body is supported by the fluid dynamic pressure bearing portion in the thrust direction and in the radial direction generated along with the rotation. Therefore, the rotating body and the rotor plate rotate smoothly around the rotation axis. In particular, unlike a mechanical bearing such as a ball bearing, it is a bearing that uses a fluid such as oil, so that it can be smoothly rotated with vibrations suppressed. Therefore, the generation of noise can be suppressed.

[0028] In particular, the spindle motor according to the present invention is different from a powerful device that can be rotated only by a stepping operation using a conventional dielectric tooth pattern. The rotor electrode part grounded in advance can be rotated continuously and smoothly. That is, the two electrode portions are not brought into contact with each other and stopped. Therefore, the recording medium can be rotated continuously and stably at a uniform speed. it can.

[0029] Further, since both electrode portions are not brought into contact with each other, damage and wear of both electrode portions can be prevented. Accordingly, vibration and sound loss can be reduced, and durability can be improved. In addition, since dust and the like due to contact can be prevented, the cleanliness around the rotor plate can be maintained at a certain level, and the recording medium is not adversely affected.

[0030] In addition, unlike the conventional dielectric tooth pattern, since the electric charge does not change every time a voltage is applied, the rotor electrode portion moves in response to the applied stator electrode portion instantaneously. start. Also from this, high followability can be secured and stable smooth rotation can be realized.

[0031] Further, since the recording medium is rotated via the rotor plate, unlike the conventional one, there is no fear that the recording medium will crawl and be deformed. Therefore, it does not adversely affect other components. Therefore, reliability can be improved.

[0032] As described above, according to the spindle motor of the present invention, the recording medium can be continuously and smoothly rotated through the rotor plate while preventing damage and wear due to contact, and the vibration can be reduced. In addition, noise reduction and durability can be improved, and reliability can be improved.

[0033] Further, the spindle motor of the present invention is the above-described spindle motor of the present invention, wherein the plurality of stator electrode portion forces are in a positional relationship in which one of the rotor electrode portions and one of the stator electrode portions completely face each other. The other stator electrode part is provided so as to be located at least in the vicinity of the fixed direction side of the adjacent rotor electrode part.

[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, when the rotor electrode portion is moved toward the other stator electrode portion by electrostatic force, both electrode portions are already close to each other. In particular, since the magnitude of the electrostatic force is inversely proportional to the distance between the two electrode portions, the rotor electrode portion can be moved quickly toward the other stator electrode portion at a higher speed. Therefore, the recording medium can be rotated in a more stable state. [0035] Further, the spindle motor of the present invention is the spindle motor of the present invention described above, wherein the width of each of the plurality of stator electrode portion forces in the circumferential direction is narrower than the width of each of the plurality of rotor electrode portions. Are arranged adjacent to each other in close proximity to each other, and the voltage application means includes at least the rotor electrode portion from the substantial center of the plurality of stator electrode portions of the plurality of stator electrodes. The drive voltage is applied to a stator electrode portion located within a range of 1Z2 of the width toward the fixed direction.

[0036] 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.

[0037] 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 in a concentrated manner only to the stator electrode part that is close to the rotor electrode part and contributes to the movement of the rotor electrode part. In particular, since the magnitude of the electrostatic force is inversely proportional to the distance between the two electrode portions, the rotor electrode portion can be pulled with a stronger electrostatic force, and can be moved quickly at a higher speed. Therefore, the recording medium can be rotated in a more stable state.

It should be noted that the voltage application means sequentially changes the application to the stator electrode portion as the rotor electrode portion moves so as to maintain the above-described positional relationship. 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. [0039] Further, the spindle motor of the present invention is the spindle motor of any one of the above-described present invention, wherein at least one of the opposing surface of the rotor plate and the surface of the stator plate is the rotor electrode portion. Alternatively, a protective film is provided so as to cover the stator electrode portion.

[0040] In the spindle motor according to the present invention, the protective film is provided so as to cover at least one of the rotor electrode portion and the stator electrode portion, so that the rotor plate is caused by some cause during the rotation. Even if an external force is applied, since the protective film is interposed, the contact electrode portion and the stator electrode portion do not directly contact 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 further enhanced.

[0041] Further, the spindle motor of the present invention is characterized in that, in the spindle motor of the present invention, a lubricating film is applied on the protective film.

[0042] In the spindle motor according to the present invention, since the lubricating film is further applied on the protective film, an external force is applied to the rotor plate for some reason during rotation as described above, and the rotor plate or stator plate Even if the lubricant film is in contact with the lubricant film or the lubricant films are in contact with each other, the frictional force at the time of contact can be reduced. Therefore, a decrease in rotational speed can be suppressed as much as possible. Moreover, since the resistance at the time of contact can be suppressed as much as possible, power saving can be achieved.

[0043] Further, since the rotor plate is slippery during rotational driving, the starting characteristics can be improved. This point power can also save power.

[0044] Further, the spindle motor of the present invention is the above-described spindle motor of the present invention, wherein at least one of the opposing surface of the rotor plate and the surface of the stator plate has the rotor electrode portion or the A solid lubricating film is provided so as to cover the stator electrode portion.

In the spindle motor according to the present invention, a solid lubricating film having both functions of a protective film and a lubricating film is provided so as to cover at least one of the rotor electrode portion and the stator electrode portion. . Therefore, even if an external force is applied to the rotor plate for some reason during rotation, the solid lubricating film is interposed, so the rotor electrode portion and the stay are directly The electrode part does not come into contact. 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 further enhanced.

[0046] Furthermore, the frictional force at the time of contact can be reduced, and a decrease in rotational speed can be suppressed as much as possible. Moreover, since the resistance at the time of contact can be suppressed as much as possible, power saving can be achieved. In addition, since the rotor plate is slippery during rotational driving, the starting characteristics can be improved. Also from this point, power saving can be achieved.

[0047] Further, in the spindle motor of the present invention, the spindle motor of the present invention has at least a gap between the rotor plate and the stator plate between the shaft and the rotating body. It is characterized in that a positioning portion that is separated by a value is provided.

[0048] In the spindle motor according to the present invention, since the positioning portion is provided between the shaft and the rotating body, the gap between the rotor plate and the stator plate can be reliably opened at least by a specified value. . Therefore, it is possible to obtain more stable rotation without contact between both electrode portions. Further, since the rotor plate and the stator plate do not come into contact with each other even during stoppage, the starting characteristics can be improved. As a result, the load at startup can be reduced and further power saving can be achieved.

[0049] 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 the fluid dynamic pressure bearing portion is a shaft facing the rotating body. A thrust dynamic pressure groove formed on at least one of the upper surface of the rotor and the lower surface of the rotating body facing the rotor plate to support the thrust force, and formed on the outer peripheral surface of the shaft in the radial direction. And a radial dynamic pressure groove for supporting the above-mentioned force.

In the spindle motor according to the present invention, when the rotating body starts to rotate, the fluid supplied between the rotating body and the shaft flows along the thrust dynamic pressure groove and the radial dynamic pressure groove. The pressure gradually increases for the first time. Then, the rotor first floats by the rotor plate force due to the pressure generated by the thrust dynamic pressure groove, and rotates while being separated from the shaft by the pressure generated by the radial dynamic pressure groove. In other words, the fluid dynamic bearing Supports thrust and radial forces that are sometimes generated on rotating bodies. As a result, the rotating body rotates smoothly around the shaft without any side shake. Thus, by providing both dynamic pressure grooves, the rotating body and the rotor plate fixed to the rotating body can be reliably and stably rotated while suppressing vibration.

[0051] Since the rotating body simultaneously receives an electrostatic force that acts between the rotor electrode portion and the stator electrode portion during rotation, the rotating body is pulled in a direction opposite to the flying direction to maintain the rotation balance. ing. From this point, stable rotation can be maintained.

[0052] Further, in the spindle motor of the present invention described above, the spindle motor of the present invention includes a flange-shaped flange portion that extends radially outward by a predetermined thickness on the outer peripheral surface of the shaft. The fluid dynamic pressure bearing portion formed is provided with a second thrust dynamic pressure groove formed on the lower surface of the flange portion and supporting the force in the thrust direction.

In the spindle motor according to the present invention, fluid flows along the second 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 second thrust dynamic pressure groove and receives a force in the direction of the stator plate, that is, the direction opposite to the direction of rising, and is pressed. . That is, the fluid dynamic pressure bearing portion can support two thrust forces directed in opposite directions along the rotation axis. As a result, the rotating body receives the floating force and the pressing force by the two thrust forces, and also receives the electrostatic force acting between the rotor electrode portion and the stator electrode portion. As a result, the rotating body rotates more stably in the thrust direction due to the balance of the three forces. Accordingly, it is possible to further reduce vibration and noise during rotation, and to operate the fluid dynamic pressure bearing portion more stably.

[0054] 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. Force on the surface of the recording medium, a suspension that supports the suspension 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 the recording Control the operation of the playhead, And a control unit for performing recording and reproduction.

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.

[0056] In particular, since the spindle motor for continuously and smoothly rotating the recording medium is provided, information can be recorded and reproduced accurately, and high quality can be achieved. In addition, since it is a spindle motor with low vibration and low noise and improved durability, high quality can be achieved from this point, and the reliability of the product can be improved.

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 top view of a shaft constituting the spindle motor shown in FIG. 2.

FIG. 4 is a bottom view of a sleeve constituting the spindle motor shown in FIG.

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

6 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. 7 is a view of the stator plate constituting the spindle motor shown in FIG. 2 as viewed from the rotor plate side.

FIG. 8 is a diagram for explaining the movement of the spindle motor shown in FIG. 2, where (a) shows a state in which a drive voltage is applied to a selected stator 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), and (c) is a diagram showing a different stator after the state shown in (b). Mark drive voltage on electrode It is a figure which shows the state which has started to move the rotor electrode part again by calorie.

FIG. 9 is a cross-sectional development view along the circumferential direction of the rotor plate and the stator plate when protective films are provided on both the rotor plate and the stator plate shown in FIG.

FIG. 10 is a developed cross-sectional view along the circumferential direction when a lubricating film is applied on the protective film on the rotor plate side of the protective film shown in FIG.

FIG. 11 is a diagram showing a second embodiment of the spindle motor according to the present invention, and is a developed sectional view along the circumferential direction of the rotor plate and the stator plate constituting the spindle motor.

FIG. 12 is a diagram for explaining the movement of the spindle motor shown in FIG. 11, where (a) shows a state in which a drive voltage is applied to the selected stator electrode part and the rotor electrode part is started to move by electrostatic force. (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. 13 is a view showing a modification of the spindle motor, and is a cross-sectional view of the spindle motor having a protrusion on the upper surface of the shaft.

FIG. 14 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. 15 is a bottom view of the flange portion shown in FIG.

FIG. 16 is a developed sectional view of the rotor plate and the stator plate constituting the spindle motor shown in FIG. 2 along the circumferential direction.

BEST MODE FOR CARRYING OUT THE INVENTION

[0058] (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. FIGS. 6, 9 and 10 are shown in a state where the cross-section along the circumferential direction is developed.

As shown in FIG. 1, the information recording / reproducing apparatus 1 of the present embodiment has 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 4 Move the scan toward the XY direction parallel to the surface of disk D. The actuator 5 to be moved, the control unit 6 for controlling the operation of the magnetic head 3 to perform recording and reproduction, the cord unit 7 for connecting the control unit 6 and the magnetic head 3, and the respective components are accommodated. A housing 8 is provided.

[0060] The sawing 8 is formed of a metal material such as aluminum in a square shape when viewed from above, and a recess 8a for accommodating each component is formed 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.

[0061] 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 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.

[0063] The magnetic head 3 has a coil section (not shown), and when recording is performed, information is output as a magnetic signal when receiving an instruction from the control section, and a disk is recorded. Record on 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 about 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 A step portion (holding portion) 20a that is inserted and can be rotated around the rotation axis L and holds the disk D is provided. A fluid body that has a rotating body 17 on the outer peripheral surface and conductive oil (fluid) W supplied to the gap and supports thrust force and radial direction force when the rotating body 17 rotates. A pressure bearing portion 18 and a rotor plate 19 having a facing surface 19a facing the stator plate 16 and fixed to the base end side of the rotating body 17 and rotating 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. 3, a plurality of dynamic pressure grooves (thrust dynamic pressure grooves) 15a that are curved from the outer edge toward the center are formed on the upper surface of the shaft 15. That is, the plurality of dynamic pressure grooves 15a have a windmill shape as a whole. As a result, when the rotating body 17 rotates, the oil W flows along the dynamic pressure groove 15a toward the center. That is, the dynamic pressure groove 15a functions as a thrust bearing portion that supports a thrust force.

[0067] On the outer peripheral surface of the shaft 15, as shown in FIG. 2, V-shaped dynamic pressure grooves (radial dynamic pressure grooves) 15b formed by linear grooves joined at a junction 15c are vertically arranged. It is formed adjacent to two levels. At this time, the dynamic pressure groove 15b is formed in a state in which the V-shape is oriented sideways so that when the rotating body 17 rotates, the junction 15c rotates so as to follow the rear force. As a result, when the rotating body 17 rotates, the oil W flows in the direction opposite to the rotating direction along the dynamic pressure groove 15b. In other words, the dynamic pressure groove 15b functions as a radial bearing portion that supports a radial force. In the present embodiment, the dynamic pressure grooves 15b are formed in two upper and lower stages, but the present invention is not limited to this, and may be formed in one stage or in three or more stages. Further, the two dynamic pressure grooves 15b may be formed in a state of being separated from each other.

The rotating body 17 includes 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. The oil W is supplied between the shaft 15 and the sleeve 21 to be filled. Also The step portion 20a 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.

Further, as shown in FIG. 4, a dynamic pressure groove (thrust dynamic pressure groove) 21a that curves from the outer edge toward the rotation axis L is formed on the lower surface of the sleeve 21, as shown in FIG. A plurality are formed. That is, the plurality of dynamic pressure grooves 21a have a windmill shape as a whole. As a result, when the rotating body 17 rotates, the oil W flows along the dynamic pressure groove 21a while being directed toward the center. That is, the dynamic pressure groove 21a functions as a thrust bearing portion that supports a thrust force. That is, the dynamic pressure groove 21a, the dynamic pressure grooves 15a and 15b, and the oil W constitute the fluid dynamic pressure bearing portion 18 described above.

[0070] As shown in FIG. 2, the rotor plate 19 is formed in a disk shape with 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. Has been. 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, and the oil W supplied between the shaft 15 and the sleeve 21 does not flow into the rotor plate 19 side. It becomes like this.

[0071] Further, as shown in FIGS. 5 and 6, the opposing surface 19a of the rotor plate 19 has a plurality of predetermined angles Θ 1 in the circumferential direction centered on the rotation axis L, that is, 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, as shown in FIGS. 6 and 7, the stator plate 16 has the predetermined angle 0 toward the circumferential direction centering 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. 6, the stator electrode portion 26 is formed so that the circumferential width W1 of the rotor electrode portion 25 and the width W2 of the stator electrode portion 26 are the same size. Yes. [0073] 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, as shown in FIG. 2, each of the plurality of stator electrode portions 26 is electrically connected to a voltage applying portion (voltage applying means) 27 via a wiring (not shown). The voltage application unit 27 applies a drive voltage only to the selected stator electrode unit 26 among the plurality of stator electrode units 26 for a predetermined time. 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.

Next, a case where various kinds 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. 8 (a), the drive voltage is applied to the stator electrode portion 26 (Sl, S4 position) located on the fixed direction (rotation direction) side of the rotor electrode portion 25. At this time, since all of the plurality of rotor electrode portions 25 are grounded in advance, a positive voltage and a negative voltage are applied to the applied stator electrode portion 26 and rotor electrode portion 25, respectively. Become. 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.

[0077] Then, due to the horizontal component of the electrostatic force F, the rotor electrode portion 25 gradually moves toward the applied stator electrode portion 26 (Sl, S4 position) as shown in FIG. 8 (b). To do. Then, as shown in FIG. 8 (c), at the same time as the rotor electrode portion 25 has moved to a position completely opposed to the applied stator electrode portion 26, 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 around 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.

[0079] On the other hand, when the rotating body 17 starts to rotate, the oil W supplied to the gap between the shaft 15 and the sleeve 21 starts to flow along the dynamic pressure grooves 15a, 15b, and 21a.

[0080] First, the oil W force near the lower surface of the sleeve 21 begins to flow toward the rotation axis L along the dynamic pressure groove 21a. Thereby, the pressure on the side close to the rotation axis L increases. Therefore, the sleeve 21 floats from the rotor plate 17. At the same time, the oil begins to flow toward the rotation axis L along the oil W force dynamic pressure groove 15a near the upper surface of the shaft 15. This increases the pressure on the side close to the rotation axis L. Therefore, the hub 20 is lifted from the shaft 15.

As a result, as shown in FIG. 6, the rotor electrode portion 25 and the stator electrode portion 26 are reliably separated by a force-constant distance G. Therefore, both the rotor plate 19 and the rotating body 17 rotate in a state where they are lifted stably.

[0082] In addition, the oil W in the vicinity of the outer peripheral surface of the shaft 15 starts to flow in the direction opposite to the rotation direction along the dynamic pressure groove 15b divided into two stages. The oil W flowing along the dynamic pressure groove 15b has the highest pressure at the junction 15c. As a result, the sleeve 21 is in a state where the radial force is supported at two points and is rotated away from the shaft 15. Therefore, the rotator 17 can rotate stably in a state where there is no side shake.

[0083] Thus, the fluid dynamic pressure bearing portion 18 supports thrust force and radial force generated during rotation. As a result, the rotating body 17 rotates smoothly around the shaft 15. In particular, unlike a mechanical bearing such as a ball bearing, it is a bearing that uses oil W, so it can be smoothly rotated with vibrations suppressed. As a result, the generation of noise can be minimized.

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 is positioned at a desired position on the disk D. Can be made. 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.

[0085] In particular, the spindle motor 2 of the present embodiment is different from a device that can be rotated only by a staging operation using a conventional dielectric tooth pattern, and a voltage is applied to the selected stator electrode unit 26. Can be applied successively, so that the rotor electrode portion 25 grounded in advance can be rotated continuously and smoothly. That is, the electrode portions 25 and 26 are not brought into contact with each other and stopped. Therefore, the disk D can be continuously and stably rotated at a uniform speed.

In this embodiment, as shown in FIG. 8 (a), 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, the rotor electrode portion 25 can be quickly moved toward the other stator electrode portion 26 at a higher speed. Therefore, the disk D can be rotated in a more stable state.

[0087] Further, since both electrode portions 25 and 26 are not brought into contact with each other, damage and wear of both electrode portions 25 and 26 can be prevented. Therefore, vibration and sound loss can be reduced, and durability can be improved. Further, since the generation of dust or the like due to contact can be prevented, the cleanliness around the rotor plate 19 can be kept constant, and the disk D is not adversely affected.

[0088] Further, unlike the conventional dielectric tooth pattern, since the electric charge does not change every time the voltage is applied, the rotor electrode portion 25 responds instantaneously to the applied stator electrode portion 26. Start moving. This also ensures high followability and realizes stable and smooth rotation.

Furthermore, since the disk D is rotated via the rotor plate 19, unlike the conventional one, there is no fear that the disk D will crawl and deform. Therefore, it does not adversely affect other components, for example, the magnetic head 3. Therefore, reliability can be improved.

[0090] As described above, according to the spindle motor 2 of the present embodiment, the disk D can be continuously and smoothly rotated through the rotor plate 19 while preventing damage and wear due to contact. Improves vibration, low noise and durability, and can improve reliability

[0091] Further, according to the information recording / reproducing apparatus 1 of the present embodiment, the spindle motor 2 for continuously and smoothly rotating the disk D is provided, so that information can be recorded / reproduced accurately, and high performance can be achieved. Quality can be improved. In addition, since it is a spindle motor 2 with low vibration and low noise and improved durability, this point power can also achieve high quality and improve product reliability.

In the first embodiment, as shown in FIG. 9, the protective film 30 covers the rotor electrode portion 25 and the stator electrode portion 26 on the opposing surface 19a of the rotor plate 19 and the surface of the stator plate 16, respectively. May be provided.

By doing so, even if an external force is applied to the rotor plate 19 for some reason during rotation, the protective films 30 are in contact with each other, so that the rotor plate 19 and the stator plate 16 are not in direct 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. Accordingly, the quality can be improved and the durability can be further enhanced.

[0094] Although the protective film 30 is provided on both the rotor plate 19 and the stator plate 16, the present invention is not limited to this, and the protective film 30 may be provided on only one of them.

In addition, when the protective film 30 described above is provided, a lubricating film 31 may be further applied on the protective film 30 as shown in FIG. At this time, as shown in FIG. 10, a lubricating film 31 may be applied to one protective film 30, or the lubricating film 31 may be applied to both protective films 30. [0096] By applying the lubricating film 31 in this way, even if an external force is applied to the rotor plate 19 for some reason during rotation and the protective film 30 and the lubricating film 31 come into contact with each other, the frictional force at the time of contact is reduced. can do. Therefore, it is possible to suppress a decrease in the rotational speed as much as possible. In addition, since the resistance at the time of contact can be suppressed as much as possible, power saving can be achieved. Further, since the rotor plate 19 is slippery during the rotational driving, the starting characteristics can be improved. From this point, it is possible to save power.

(Second embodiment)

Next, a second embodiment of the spindle motor according to the present invention will be described with reference to FIG. 11 and FIG. Note that the same reference numerals in the second embodiment denote the same parts as those in the first embodiment, and a description thereof will be omitted. FIG. 11 shows a state in which the 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 portion 25 and the circumferential direction of the stator electrode portion 26 are directed. Whereas the width W2 is the same size, the stator electrode portion 41 of the second embodiment is formed such that the circumferential force in the direction W3 is narrower than the width W1 of the rotor electrode portion 25. Narrow in the circumferential direction!

That is, in the spindle motor 40 of this embodiment, as shown in FIGS. 11 and 12, the width W3 of each stator electrode portion 41 is about 1Z3 wider than the width W1 of the rotor electrode portion 25. Is formed. The stator electrode portions 41 having a small width are arranged adjacent to each other in close proximity. That is, a plurality of stator electrode portions 41 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 25 are located, about three stator electrode portions 41 are always located in a state of facing each rotor electrode portion 25.

In addition, the rotor electrode portion 25 of the present embodiment is configured integrally with the rotor plate 19.

That is, the rotor plate 19 is formed of a conductive material, and the concave portion 19b is formed by cutting a predetermined position of the facing surface 19a. As a result, an uncut portion (protruded portion) can be used as the rotor electrode portion 25.

[0100] Further, the surface of the stator plate 16 is protected so as to cover the plurality of stator electrode portions 41. A solid lubricating film 42 having both a film and a lubricating film is provided.

[0101] When the spindle motor 40 configured as described above is operated, as shown in FIG. 12, the voltage application unit 27 starts from the approximate center of the rotor electrode unit 25 among the plurality of stator electrode units 41. A drive voltage is applied to the stator electrode portion 41 located in the range (Al, A2, A3 area) directed in a certain direction (rotation direction) by 1Z2 of the width of the rotor electrode portion 25.

In other words, the drive voltage is applied in a concentrated manner only to the stator electrode part 41 that is close to the rotor electrode part 25 and contributes to the movement of the rotor electrode part 25. In particular, the magnitude of the electrostatic force F is inversely proportional to the distance between the electrode portions 25 and 41, so the rotor electrode portion 25 can be pulled with a stronger electrostatic force F and moved quickly at a faster speed. be able to.

[0103] Furthermore, since the stator electrode part 41 having a narrow circumferential width W3 is arranged close to the rotor electrode part 25, all rotor electrode parts 25 (Rl, R2, R3 positions) must always be moved simultaneously. Can do. Therefore, the disk D can be rotated in a more stable state.

It should be noted that the voltage application unit 27 sequentially changes the application to the stator electrode unit 41 as the rotor electrode unit 25 moves so as to maintain the above-described positional relationship. Further, since the width W3 of the stator electrode portion 41 is made as narrow as possible and the number of the stator electrode portions 41 is increased, the fluctuation range of the electrostatic force F can be reduced. Therefore, the above-described effect can be further enhanced.

[0105] Further, since the solid lubricating film 42 having both functions of a protective film and a lubricating film is provided so as to cover the stator electrode portion 41, an external force is applied to the rotor plate 19 for some reason during the rotation. Even if added, the rotor plate 19 and the stator plate 16 are not in direct contact. Therefore, mechanical damage to both electrode portions 25 and 41 can be prevented, and damage due to discharge can be prevented. Therefore, quality can be improved and durability can be further enhanced.

[0106] Further, the frictional force at the time of contact can be reduced, and a decrease in rotational speed can be suppressed as much as possible. Furthermore, since the resistance at the time of contact can be suppressed as much as possible, power saving can be achieved. Power! In addition, since the rotor plate 19 is slippery during rotational driving, the starting characteristics can be improved. This point power can also save power.

[0107] The technical scope of the present invention is not limited to the above-described embodiments. Various changes can be made without departing from the spirit of the invention.

For example, in each of the above embodiments, as shown in FIG. 13, a protrusion (positioning) that separates between the rotor plate 19 and the stator plate 16 by at least a specified value between the shaft 15 and the rotating body 17. Part) 50 may be provided. As shown in FIG. 13, the protrusion 50 may be provided on the upper surface of the shaft 15 or may be provided on the lower surface of the hub 20. Further, the height of the protrusion 50 is formed lower than the flying height of the rotor plate 19.

By providing the protrusions 50 in this way, the gap G between the rotor plate 19 and the stator plate 16 can be surely opened at least by a specified value. Therefore, it is possible to obtain more stable rotation without contact between the electrode portions 25 and 26 (41). Further, since the rotor plate 19 and the stator plate 16 do not come into contact with each other even when stopped, the starting characteristics can be improved. Therefore, the load at the time of starting can be reduced and further power saving can be achieved.

In each of the above embodiments, the two dynamic pressure grooves, that is, the dynamic pressure groove 15a formed on the upper surface of the shaft 15 and the dynamic pressure groove 21a formed on the lower surface of the sleeve 21 are used as the dynamic pressure groove for thrust. However, it is only necessary to form at least one of the dynamic pressure grooves 15a (or 21a) which does not require two dynamic pressure grooves. However, it is preferable to form both dynamic pressure grooves 15a and 21a at the same time as in this embodiment.

Further, as shown in FIG. 14, the flange portion 60 is formed on the shaft 15, and the dynamic pressure groove (second thrust dynamic pressure groove) 60a shown in FIG. 15 is formed on the lower surface of the flange portion 60. It doesn't matter.

[0112] As shown in Fig. 14, the flange portion 60 is formed in a bowl shape with the outer peripheral surface force of the shaft 15 extending radially outward by a predetermined thickness and expanding in diameter. In FIG. 14, the case where the flange portion 60 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 60 may be formed near the middle of the shaft 15.

Then, on the lower surface of the flange portion 60, as shown in FIG. 15, the dynamic pressure that curves from the outer edge toward the rotation axis L is similar to the dynamic pressure groove 21a formed on the lower surface of the sleeve 21. A plurality of grooves 60a are formed. That is, the plurality of dynamic pressure grooves 60a have a windmill shape as a whole. As a result, when the rotating body 17 rotates, the oil W is centered along the dynamic pressure groove 60a. It is flowing toward you. That is, the dynamic pressure groove 60a functions as a thrust bearing portion that supports a force in the thrust direction.

[0114] In the case where the flange portion 60 having the dynamic pressure groove 60a formed on the lower surface is provided as described above, when the rotating body 17 starts to rotate, the oil W is supplied to the dynamic pressure grooves 15a, 15b, 21a, 60a. It begins to flow along, and pressure begins to increase at each position. At this time, the oil W flowing along the dynamic pressure groove 15b becomes the highest pressure at the junction 15c. For this reason, 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 rotate stably without any side shake.

[0115] On the other hand, the pressure of the oil W flowing along the dynamic pressure grooves 15a and 21a is highest on the side closer to the rotation axis L. Therefore, the rotating body 17 and the rotor plate 19 are lifted from the stator plate 16. At the same time, the oil W flowing along the dynamic pressure groove 60a formed on the lower surface of the flange portion 60 also increases in pressure on the side close to the rotation axis L. However, the pressure generated in the dynamic pressure groove 60 a is generated on the lower surface side of the flange portion 60 formed in the fixed shaft 15. Therefore, the rotating body 17 receives the pressure and receives a force in the direction of the stator plate 16 in the direction of the force, that is, the direction opposite to the flying direction, and is pressed. That is, in this case, the fluid dynamic pressure bearing portion 18 can support two thrust forces directed in the opposite directions along the rotation axis L.

[0116] Then, the rotating body 17 rotates while receiving both the rising force and the pressing force by the two thrust forces. 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 to the stator plate 16 side 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 to operate the fluid dynamic pressure bearing portion 18 more stably.

[0118] As an example of the recording / reproducing head, the magnetic head described as an example of a magnetic head is used. The head is not limited to this method, as long as it is a head that performs recording and reproduction. For example, a near-field optical head that performs recording / reproduction using near-field light may be used as the recording / reproducing head.

[0119] It should be noted that each of the stator electrode portions 26 described above is of course arranged at an angle narrower than the predetermined angle θ1, and is not limited to this. As shown in FIG. 16, each of the state electrode portions 26 may be arranged at a predetermined angle Θ4 wider than the predetermined angle θ1.

Thus, even when the spacing force of the stator electrode portion 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 portion 26, the rotation of the rotating body 17 is maintained.

[0121] According to the powerful feature, the number of stator electrode portions 26 can be reduced more than that in FIG. 7 by arranging each of the stator electrode portions 26 for each predetermined angle Θ4. Cost can be reduced.

Industrial applicability

[0122] According to the spindle motor of the present invention, it is possible to rotate the recording medium continuously and smoothly through the aperture plate while preventing damage and wear due to contact, thereby reducing vibration and noise. And the durability can be improved and the reliability can be improved.

[0123] Also, according to the information recording / reproducing apparatus of the present invention, since the spindle motor for continuously and smoothly rotating the recording medium is provided, information can be recorded and reproduced accurately, and high quality匕匕 can be planned.

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 with a certain clearance from the shaft and can be rotated about the rotation axis, and has a holding portion for holding the recording medium on an outer peripheral surface, and is supplied to the clearance A fluid dynamic pressure bearing portion that has a conductive fluid and supports a thrust force and 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; Prepared,

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] 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 stator electrode part of the Spindle motor.

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

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.

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

A spindle motor characterized in that a protective film is provided on at least one of the opposing surface of the rotor plate and the surface of the stator plate so as to cover the rotor electrode portion or the stator electrode portion.

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

A spindle motor, wherein a lubricating film is applied on the protective film.

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

At least one of the opposing surface of the rotor plate and the surface of the stator plate is provided with a solid lubricating film so as to cover the rotor electrode portion or the stator electrode portion. motor.

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

A spindle motor characterized in that a positioning portion for separating the rotor plate and the stator plate by at least a specified value is provided between the shaft and the rotating body.

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

The shaft is formed in a columnar shape,

The fluid dynamic pressure bearing portion is formed on at least one of an upper surface of the shaft facing the rotating body or a lower surface of the rotating body facing the rotor plate, and supports a thrust dynamic pressure groove. And the radial direction formed on the outer peripheral surface of the shaft. A spindle motor comprising a radial dynamic pressure groove for supporting a direction force.

[10] The spindle motor according to claim 9,

On the outer peripheral surface of the shaft, a flange-like flange portion extending radially outward by a predetermined thickness is formed,

The fluid dynamic pressure bearing portion includes a second thrust dynamic pressure groove formed on a lower surface of the flange portion and supporting the thrust force.

[11] The spindle motor according to any one of claims 1, 2, and 5 to 10, and

A 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.

[12] The spindle motor according to claim 3,