CN103368347A - Brushless motor and disc driving apparatus - Google Patents

Brushless motor and disc driving apparatus Download PDF

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Publication number
CN103368347A
CN103368347A CN201310090813XA CN201310090813A CN103368347A CN 103368347 A CN103368347 A CN 103368347A CN 201310090813X A CN201310090813X A CN 201310090813XA CN 201310090813 A CN201310090813 A CN 201310090813A CN 103368347 A CN103368347 A CN 103368347A
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CN
China
Prior art keywords
brushless motor
armature
wheel hub
protuberance
magnet
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN201310090813XA
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Chinese (zh)
Inventor
姫野敏和
杜红兵
桥本纯一
榎园和也
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Nidec Corp
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Nidec Corp
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Publication date
Application filed by Nidec Corp filed Critical Nidec Corp
Priority to CN201510237460.0A priority Critical patent/CN104852503A/en
Publication of CN103368347A publication Critical patent/CN103368347A/en
Pending legal-status Critical Current

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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02KDYNAMO-ELECTRIC MACHINES
    • H02K5/00Casings; Enclosures; Supports
    • H02K5/04Casings or enclosures characterised by the shape, form or construction thereof
    • H02K5/16Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields
    • H02K5/165Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields radially supporting the rotor around a fixed spindle; radially supporting the rotor directly
    • GPHYSICS
    • G11INFORMATION STORAGE
    • G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B17/00Guiding record carriers not specifically of filamentary or web form, or of supports therefor
    • G11B17/02Details
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02KDYNAMO-ELECTRIC MACHINES
    • H02K29/00Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices

Abstract

The invention provides a brushless motor and a disc driving apparatus. A stationary part of the brushless motor comprises a coil-pattern plate-shaped armature, and a plate-shaped magnetic component which encloses the central axis, wherein the magnetic component is in contact with an upper surface of the armature. Furthermore, a rotation part of the brushless motor comprises a magnet which is disposed to be opposite to the upper surface of the armature. Furthermore, the periphery of the magnetic component is configured to be at a position that is nearer a radial outer side than the periphery of the magnet and the coil pattern. Therefore, absorption of magnetic flux by the magnetic component itself is suppressed, and thus the driving efficiency of the brushless motor is improved.

Description

Brushless motor and disk drive device
Technical field
The present invention relates to a kind of brushless motor and disk drive device.
Background technology
In hard disk unit, be equipped be used to the brushless motor that makes disc spins.For example, in the SG185981 communique, put down in writing a kind of brushless motor in the past.Permanent magnet synchronous motor in this communique comprises permanent magnet and armature, and described permanent magnet is equipped at least one party in top yoke and the bottom yoke, and described armature is configured in the air gap between this permanent magnet and the opposing party's the yoke.
Such as the record among the SG185981, compare in the so-called radial clearance structure of diametrically contraposition with permanent magnet with making armature, make armature and permanent magnet be conducive to the slimming of motor in axial opposed so-called end play structure.Yet in radial clearance structure and end play structure, the configuration of each parts in the motor is fully different.Therefore, in the end play structure, in order to improve the drive efficiency of motor, need to consider a kind of structure different from the radial clearance structure.
Summary of the invention
The rotating part that the brushless motor of illustrated the first invention of the application comprises stationary part and can rotate by Bearning mechanism and with respect to stationary part.Stationary part comprises armature, the substrate parts that supports armature and tabular magnetic part.Armature is at the radial outside edge of Bearning mechanism and the Directional Extension of the central axis quadrature of upper downward-extension.Magnetic part contacts with the upper surface of armature and this magnetic part surrounds central axis.Rotating part comprises wheel hub and magnet.Wheel hub comprises as the top plate portion of magnetic and from the wheel hub protuberance as magnetic of top plate portion towards the below extension.Magnet is fixed in wheel hub, and opposed with the upper surface of armature.Armature comprises a plurality of coil pattern along circumferential array.The peripheral part of magnetic part is configured in than the outer peripheral face of described magnet and the coil pattern position by radial outside.
According to illustrated the first invention of the application, can reduce leaking into than the magnetic flux of magnetic part by the position of radial outside.And the peripheral part of magnetic part is configured in than the outer peripheral face of magnet and the coil pattern position by radial outside.Therefore, also suppressed the absorption of magnetic part self to magnetic flux.Consequently, improved the drive efficiency of brushless motor.
The rotating part that the brushless motor of illustrated the second invention of the application comprises stationary part and can rotate by Bearning mechanism and with respect to stationary part.Stationary part comprises tabular armature and supports the substrate parts of armature.Armature is at the radial outside edge of Bearning mechanism and the Directional Extension of the central axis quadrature of upper downward-extension.Rotating part comprises wheel hub, magnet and rotor yoke.Wheel hub comprises as the top plate portion of magnetic and from the wheel hub protuberance as magnetic of top plate portion towards the below extension.The upper surface of magnet and armature is opposed.The lower surface of rotor yoke and armature is opposed.Bearning mechanism comprises lubricating fluid between the parts of the parts of stationary part side and rotating part side.At least one party in stationary part and the rotating part comprises for the dynamic pressure groove row that produce dynamic pressure at lubricating fluid.
Substrate parts comprises base plate, roughly substrate protuberance cylindraceous and tubular face.Base plate is at the downside edge of armature and the Directional Extension of central axis quadrature.The substrate protuberance than wheel hub protuberance by the position of radially inner side from base plate towards above extend.The tubular face is positioned at the radial outside of rotor yoke.The liquid level of lubricating fluid is positioned at than the position of wheel hub protuberance by radially inner side.Rotor yoke is fixed in the wheel hub protuberance.The outer peripheral face of substrate protuberance and wheel hub protuberance or rotor yoke across the first gap at diametrically contraposition.The peripheral part of tubular face and rotor yoke across the second gap at diametrically contraposition.The interval radially in the first gap is less than the interval radially in the second gap.
According to illustrated the second invention of the application, suppressed the turnover of the gas of the first gap location.Therefore, suppressed the evaporation of lubricating fluid.Consequently, thus the rotational resistance that has suppressed Bearning mechanism has improved the drive efficiency of brushless motor.
By following detailed description to the preferred embodiment for the present invention, with reference to accompanying drawing, can more clearly understand above-mentioned and other feature of the present invention, key element, step, characteristics and advantage.
Description of drawings
Fig. 1 is the longitudinal section of the related brushless motor of the first execution mode.
Fig. 2 is the longitudinal section of the related disk drive device of the second execution mode.
Fig. 3 is the longitudinal section of the related brushless motor of the second execution mode.
Fig. 4 is the longitudinal section of the related sleeve of the second execution mode.
Fig. 5 is the vertical view of the related sleeve of the second execution mode.
Fig. 6 is the partial, longitudinal cross-sectional of the related brushless motor of the second execution mode.
Fig. 7 is the partial, longitudinal cross-sectional of the related brushless motor of the second execution mode.
Fig. 8 is the vertical view of the related stationary part of the second execution mode.
Fig. 9 is the partial, longitudinal cross-sectional of the related brushless motor of variation.
Figure 10 is the partial, longitudinal cross-sectional of the related brushless motor of variation.
Embodiment
Below, with reference to accompanying drawing the illustrated execution mode of the present invention is described.In addition, in this application, respectively the direction parallel with the central axis of brushless motor is called " axially ", will be called " radially " with the direction of the central axis quadrature of brushless motor, will be called along the direction of the circular arc centered by the central axis of brushless motor " circumferentially ".And, in this application, take axially as above-below direction, take magnet side as upper, shape and the position relationship of each several part is described with respect to armature.But, the above-below direction that this just defines for the convenience that illustrates, do not limit brushless motor involved in the present invention and disk drive device during fabrication and when using towards.
And in this application, " parallel direction " also comprises the direction of almost parallel.And in this application, " direction of quadrature " also comprises the roughly direction of quadrature.
Fig. 1 is the longitudinal section of the related brushless motor 11A of the first execution mode.As shown in Figure 1, brushless motor 11A comprises stationary part 2A and rotating part 3A.Rotating part 3A is supported for respect to stationary part 2A and can rotates by Bearning mechanism 4A.
Stationary part 2A comprises substrate parts 21A, armature 22A and magnetic part 25A.Armature 22A is supported by substrate parts 21A.Armature 22A is tabularly along the direction with central axis 9A quadrature at the radial outside of Bearning mechanism 4A and expands.And armature 22A comprises a plurality of coil pattern 221A.A plurality of coil pattern 221A are along circumferential array.
Substrate parts 21A comprises base plate 51A, substrate protuberance 52A and tubular face 55A.Base plate 51A is at the downside edge of armature 22A and the Directional Extension of central axis 9A quadrature.Substrate protuberance 52A is positioned at than hereinafter described wheel hub protuberance 62A by the position of radially inner side, and is roughly cylindricly towards the top from base plate 51A and extends.Tubular face 55A is positioned at the radial outside of hereinafter described rotor yoke 35A.
Rotating part 3A comprises wheel hub 32A, magnet 34A and rotor yoke 35A.Wheel hub 32A comprises as the top plate portion 61A of magnetic with as the wheel hub protuberance 62A of magnetic.Wheel hub protuberance 62A extends towards the below from top plate portion 61A.Magnet 34A is fixed in wheel hub 32A.And the upper surface of magnet 34A and armature 22A is opposed.Rotor yoke 35A is fixed in wheel hub protuberance 62A.And the lower surface of rotor yoke 35A and armature 22A is opposed.
Magnetic part 25A is for surrounding the tabular parts of central axis 9A.Magnetic part 25A contacts with the upper surface of armature 22A.Magnetic part 25A has reduced and has leaked into the magnetic flux by the position of radial outside than magnetic part 25A.And in this brushless motor 11A, the peripheral part of magnetic part 25A is configured in the position by radial outside than the outer peripheral face of magnet 34A and coil pattern 221A.Therefore, suppressed the absorption of magnetic part 25A self to magnetic flux.Consequently, improved the drive efficiency of brushless motor 11A.
Bearning mechanism 4A comprises lubricating fluid 41A between the parts of the parts of stationary part 2A side and rotating part 3A side.The liquid level of lubricating fluid 41A is positioned at the position by radially inner side than wheel hub protuberance 62A.And at least one party among stationary part 2A and the rotating part 3A comprises dynamic pressure groove row 230A.When brushless motor 11A drives, produce dynamic pressure by dynamic pressure groove row 230A at lubricating fluid 41A.
In such brushless motor 11A, the outer peripheral face of substrate protuberance 52A and wheel hub protuberance 62A or rotor yoke 35A across the first gap 81A at diametrically contraposition.And, the peripheral part of tubular face 55A and rotor yoke 35A across the second gap 82A at diametrically contraposition.The interval d1 radially of the first gap 81A is less than the interval d2 radially of the second gap 82A.Therefore, suppressed to pass in and out at the gas at 81A place, the first gap.Therefore, suppressed the evaporation of lubricating fluid 41A.Consequently, suppress the rotational resistance at Bearning mechanism 4A place, thereby improved the drive efficiency of brushless motor 11A.
Fig. 2 is the longitudinal section of the related disk drive device of the second execution mode 1.When disk drive device 1 makes disk 12 rotation disk 12 is carried out reading and writing of information.As shown in Figure 2, disk drive device 1 comprises brushless motor 11, disk 12, access section 13 and outer cover 14.
Brushless motor 11 supporting disks 12 and disk 12 is rotated centered by central axis 9.Brushless motor 11 is included in the substrate parts 21 that the downside of disk 12 is radially expanded.The rotating part 3 of brushless motor 11, disk 12 and access section 13 are contained in the inside of the housing that is made of substrate parts 21 and outer cover 14.Access section 13 makes magnetic head 131 move along the recording surface of disk 12, and disk 12 is carried out reading and writing of information.In addition, substrate parts 21 both can be made of parts, and the assembly that also can be formed by a plurality of parts of combination consists of.
In addition, disk drive device 1 also can comprise the disk 12 more than two.And access section 13 also can be only carries out a side in the reading and writing of information to disk 12.
Next, the structure of above-mentioned brushless motor 11 described.Fig. 3 is the longitudinal section of brushless motor 11.As shown in Figure 3, brushless motor 11 comprises stationary part 2 and rotating part 3.Stationary part 2 is relatively static with respect to substrate parts 21 and outer cover 14.Rotating part 3 is supported for respect to stationary part 2 and can rotates by Bearning mechanism 4.
Stationary part 2 in the present embodiment comprises substrate parts 21, armature 22, sleeve 23, cap 24 and magnetic part 25.
Substrate parts 21 supports armature 22 and sleeve 23.Substrate parts 21 is such as obtaining by the casting of the metals such as aluminium alloy.As shown in Figure 3, substrate parts 21 comprises base plate 51, substrate protuberance 52, substrate through hole 53, armature maintaining part 54 and tubular face 55.
Base plate 51 is at the downside edge of armature 22 and the Directional Extension of central axis 9 quadratures.Substrate protuberance 52 is roughly cylindricly towards the top from the interior perimembranous of base plate 51 and extends.Substrate protuberance 52 is positioned at than the position of aftermentioned wheel hub protuberance 62 by radially inner side.Substrate through hole 53 is downward-extension on the radially inner side of substrate protuberance 52.
Armature maintaining part 54 than aftermentioned rotor yoke 35 by the position of radial outside from base plate 51 towards above outstanding.Armature maintaining part 54 comprises wall section 541 and circumferentia 542.The outboard end edge of wall section 541 and armature 22 is at diametrically contraposition.Circumferentia 542 is expanded towards radially inner side from the bottom of wall section 541.Armature 22 is configured in the radially inner side of wall section 541 and is supported by circumferentia 542.In addition, the outboard end edge of armature 22 both can be opposed under the state that contacts with wall section 541, also can with wall section 541 radially across the gap and opposed.
Tubular face 55 is roughly cylindricly vertically between the upper surface of base plate 51 and circumferentia 542 and extends.Tubular face 55 be positioned at rotor yoke 35 radial outside and with the outer peripheral face of aftermentioned plectane section 71 at diametrically contraposition.
Armature 22 be along with the tabular circuit board of the Directional Extension of central axis 9 quadratures.Armature 22 is configured in than Bearning mechanism 4 by radial outside, than aftermentioned magnet 34 side and than the position of the plectane section 71 top sides of aftermentioned rotor yoke 35 on the lower.And the outboard end edge of armature 22 is by being fixed on armature maintaining part 54 such as methods such as binding agents.Armature 22 comprises the coil pattern 221 along a plurality of conductivity of circumferential array.Each coil pattern 221 preferably disposes centered by the coil axes that extends vertically in the shape of a spiral.
Sleeve 23 extended in being roughly cylindricly vertically on every side of aftermentioned axle 31.The bottom of sleeve 23 is inserted in the substrate through hole 53 and is fixed in the inner peripheral surface of substrate protuberance 52.The outer peripheral face of the inner peripheral surface of sleeve 23 and axle 31 is at diametrically contraposition.And the opening of the bottom of sleeve 23 is sealed by cap 24.
Rotating part 3 in the present embodiment comprises axle 31, wheel hub 32, endless member 33, a plurality of magnet 34 and rotor yoke 35.
Axle 31 is the parts that extend vertically.The material of axle 31 is such as metals such as use stainless steels.Rotation centered by central axis 9 when axle 31 is supported by sleeve 23 and cap 24 across lubricating fluid 41.The upper end of axle 31 is more outstanding upward than the upper surface of sleeve 23.
Wheel hub 32 comprises top plate portion 61, wheel hub protuberance 62 and dish support portion 63.In the present embodiment, wheel hub 32 integral body are formed by magnetic.Top plate portion 61 radially and is circumferentially expanded above armature 22.The end edge portion of the radially inner side of top plate portion 61 is fixed on the upper end of axle 31.Wheel hub protuberance 62 is roughly cylindricly towards the below from top plate portion 61 and extends.In addition, wheel hub 32 both can be made of parts, and the assembly that also can be formed by a plurality of parts of combination consists of.
Dish support portion 63 is at the radial outside supporting disk 12 of top plate portion 61.Dish support portion 63 comprise the first supporting surface 631 cylindraceous roughly and from the bottom of the first supporting surface 631 towards the second supporting surface 632 of radial outside expansion.The interior perimembranous of preferred disk 12 contacts with the first supporting surface 631.Thus, disk 12 radially is being positioned.And the lower surface of disk 12 contacts with the second supporting surface 632.Thus, disk 12 axially is being positioned.
Endless member 33 is the circular parts that are positioned at the radially inner side of wheel hub protuberance 62.The upper surface of endless member 33 contacts with the lower surface of top plate portion 61.And the face of the radial outside of endless member 33 is by being pressed into and/or the method such as binding agent is fixed on the inner peripheral surface of wheel hub protuberance 62.
Sleeve 23 and cap 24, and axle 31, wheel hub 32 and endless member 33 between have lubricating fluid 41.The liquid level of lubricating fluid 41 is between the inner peripheral surface of the outer peripheral face of sleeve 23 and endless member 33.Axle 31, wheel hub 32 and endless member 33 are supported for and can rotate across lubricating fluid 41 with respect to sleeve 23 and cap 24.That is, in the present embodiment, by as the sleeve 23 of the parts of stationary part 2 sides and cap 24, consist of Bearning mechanism 4 as axle 31, wheel hub 32 and the endless member 33 of the parts of rotating part 3 sides and the lubricating fluid 41 that is present in therebetween.Lubricating fluid 41 for example uses the lubricating fluid of polybasic ester class oil or di esters.
Fig. 4 is the longitudinal section of sleeve 23.As shown in Figure 4, the inner peripheral surface at sleeve 23 is provided with radial dynamic pressure groove row 231.Radial dynamic pressure groove row for example form herringbone shown in Figure 4.If brushless motor 11 is driven, then by radial dynamic pressure groove row, in the lubricating fluid 41 generation dynamic pressures radially that are present between sleeve 23 and the axle 31.Axle 31 by this dynamic pressure and with respect to sleeve 23 radially supported.
Fig. 5 is the vertical view of sleeve 23.As shown in Figure 5, the upper surface at sleeve 23 is provided with axial hydrodynamic groove row 232.Axial hydrodynamic groove row for example form herringbone shape shown in Figure 5.If brushless motor 11 is driven, then by axial hydrodynamic groove row 232, produce axial dynamic pressure at the lubricating fluid 41 that is present between sleeve 23 and the wheel hub 32.By this dynamic pressure, wheel hub 32 with respect to sleeve 23 axially supported.In addition, axial hydrodynamic groove row for example also can be the spiral helicine groove row of the pressure rise that makes radially inner side.
In addition, at least one party that is arranged in the outer peripheral face of the inner peripheral surface of sleeve 23 and axle 31 of radial dynamic pressure groove row 231 gets final product.And at least one party that axial hydrodynamic groove row 232 are arranged in the lower surface of the upper surface of sleeve 23 and top plate portion 61 gets final product.
Return Fig. 3.A plurality of magnet 34 are by being fixed on the lower surface of the top plate portion 61 of wheel hub 32 such as binding agent etc.A plurality of magnet 34 are positioned at the top of armature 22.The lower surface of each magnet 34 for the coil pattern 221 of the upper surface that is arranged on armature 22 at axial opposed magnetic pole strength.The mode that a plurality of magnet 34 are alternately arranged with the magnetic pole strength of the magnetic pole strength of the N utmost point and the S utmost point is along circumferential array.In addition, also can replace a plurality of magnet 34 and use a circular magnet that alternately is magnetized to the N utmost point and the S utmost point along circumferential.
Rotor yoke 35 is the magnetic that together rotates with wheel hub 32 and magnet 34.Rotor yoke 35 in the present embodiment comprises plectane section 71 and yoke protuberance 72.Plectane section 71 than armature 22 on the lower side, be circularly by the position of radially inner side than the base plate 51 top sides of substrate parts 21 and than the tubular face 55 of substrate parts 21 and expand.The lower surface of the upper surface of plectane section 71 and armature 22 is axially opposed.Yoke protuberance 72 than armature 22 by the position of radially inner side from plectane section 71 towards above be roughly cylindricly and extend.And yoke protuberance 72 is fixed in wheel hub protuberance 62.
In such brushless motor 11, if provide drive current to the coil pattern 221 of armature 22, then produce the magnetic flux that connects vertically armature 22.And, form the magnetic loop via armature 22, a plurality of magnet 34, wheel hub 32 and rotor yoke 35.And, produce circumferential torque by the effect of this magnetic flux.Consequently, rotating part 3 rotates centered by central axis 9 with respect to stationary part 2.The disk 12 that is supported by wheel hub 32 together rotates centered by central axis 9 with rotating part 3.
Next, magnetic part 25 is further specified.
Fig. 6 and Fig. 7 are the partial, longitudinal cross-sectional of brushless motor 11.Fig. 8 is the vertical view of stationary part 2.Such as Fig. 6 and shown in Figure 8, magnetic part 25 is configured in the upper surface of substrate parts 21 and armature 22.Magnetic part 25 is for tabular parts and be and surround central axis 9 circularly.And, magnetic part 25 and roughly coaxially configuration of central axis 9.The lower surface of magnetic part 25 contacts with the upper surface of substrate parts 21 and the upper surface both sides of armature 22.
Magnetic part 25 is formed by magnetics such as iron or stainless steels.Therefore, between magnetic part 25 and magnet 34, produce magnetic attraction.This magnetic attraction comprises axial thrust load.Wheel hub 32 is drawn by basad parts 21 side draughts of magnetic attraction that produce between magnetic part 25 and magnet 34.Consequently, rotating part 3 is stably supported with respect to stationary part 2.
When brushless motor 11 drives, the dynamic pressure that produces by axial hydrodynamic groove row 232, the pressure that wheel hub 32 is produced towards the top.Thereby wheel hub 32 is subject to by stably rotating towards the pressure of top and the magnetic attraction towards the below that is produced by magnetic part 25 that this dynamic pressure produces.
Particularly, shown in brushless motor 11, be armature 22 and magnet 34 when axial opposed structure, between armature 22 and magnet 34, alternately produce axial magnetic attraction and magnetic repulsion.This magnetic attraction and magnetic repulsion may become the main cause of brushless motor 11 vibrations.Yet, in the brushless motor 11 of present embodiment, between magnetic part 25 and magnet 34, do not produce this magnetic attraction and magnetic repulsion, but produce continuous magnetic attraction.Thus, the vibration of brushless motor 11 is inhibited.
And as shown in Figure 7, the sleeve 23 in the present embodiment comprises the sleeve protuberance 233 of giving prominence to towards radial outside from the upper end of sleeve 23.The upper surface of the lower surface of sleeve protuberance 233 and endless member 33 is axially opposed.If wheel hub 32 is because the magnetic attraction of 34 of magnetic part 25 and magnet and basad parts 21 sides are attracted, then contacting between the lower surface of the upper surface of endless member 33 and sleeve protuberance 233 is inhibited.
And the flux leakage that magnetic part 25 has suppressed to produce between armature 22 and magnet 34 is to the position of leaning on radial outside than magnetic part 25.Leak towards radial outside if suppressed magnetic flux, then between armature 22 and magnet 34, magnetic flux can obtain using efficiently.Therefore, the expression torque phase is improved for the torque constant of the generation efficiency of drive current.
And as shown in Figure 6, in this brushless motor 11, the peripheral part of magnetic part 25 is configured in than the position of the outer peripheral face of magnet 34 and coil pattern 221 by radial outside.That is, at least peripheral part of magnetic part 25 is not present between the lower surface and coil pattern 221 of magnet 34.Thus, reduced magnetic part 25 self to the uptake of magnetic flux.Therefore, magnetic flux obtains using between armature 22 and magnet 34 more efficiently.Consequently, the torque constant of brushless motor 11 is further enhanced.That is, the drive efficiency of brushless motor 11 is improved.
And in this brushless motor 11, the minimum value of the distance between the upper surface of the lower surface of magnet 34 and magnetic part 25 is larger than the minimum value of the distance between the upper surface of the lower surface of magnet 34 and coil pattern 221.Therefore, than magnetic part 25, the magnetic flux that produces from magnet 34 is more prone to flow to coil pattern 221.Thus, further reduced magnetic part 25 self to the uptake of magnetic flux.
And such as Fig. 6 and shown in Figure 8, in the present embodiment, the part of coil pattern 221 is positioned at the position of leaning on radial outside than the perimembranous of magnetic part 25.Thus, expanded the area of coil pattern 221.Thus, can produce stronger magnetic flux in coil pattern 221.But coil pattern 221 also can only be configured in the zone of leaning on radially inner side than the interior perimembranous of magnetic part 25.
And the magnetic part 25 in the present embodiment is the parts with the circuit board split that consists of armature 22.And, magnetic part 25 substrate parts 21 than wall section 541 scope by the upper surface both sides of the upper surface of radial outside and armature 22 in expand.And magnetic part 25 is fixed on the upper surface both sides of upper surface and the armature 22 of substrate parts 21 by for example binding agent.Therefore, having limited armature 22 by magnetic part 25 moves towards the top.
That is, the magnetic part in the present embodiment 25 the first function of having realized rotating part 3 downward side draughts are drawn, prevent the 3rd function that flux leakage moves towards the top to the second function of radial outside and restriction armature 22.
And as shown in Figure 6, the wheel hub 32 in the present embodiment comprises the first lower surface 321, the second lower surface 322 and step surface 323.The first lower surface 321 radially and is circumferentially expanded above magnet 34.Step surface 323 is roughly cylindricly towards the below from the end edge portion of the radial outside of the first lower surface 321 and extends.The second lower surface 322 is further expanded to radial outside from the bottom of step surface 323.That is, the second lower surface 322 is positioned at than the position of the first lower surface 321 by radial outside and downside.
Magnet 34 is fixed in the first lower surface 321 and step surface 323 by binding agent 80.That is, the upper surface of magnet 34 contacts with the first lower surface 321 via binding agent 80.And the outer peripheral face of magnet 34 contacts with step surface 323 via binding agent 80.
If the lower surface of magnet 34 is positioned at the position than the second lower surface 322 top sides, then binding agent 80 is easily in the lower surface expansion as the magnet 34 of magnetic pole strength.Yet in the present embodiment, the lower surface of magnet 34 is positioned at than the second lower surface 322 position of side on the lower.And, between the outer peripheral face of the second lower surface 322 and magnet 34, have binding agent 80.Thus, suppressed the lower surface expansion of binding agent 80 towards magnet 34.
And in this brushless motor 11, the interior perimembranous of magnetic part 25 is positioned at the position of leaning on radial outside than the outer peripheral face of magnet 34.Thus, the lower surface that makes magnet 34 towards than the second lower surface 322 on the lower the position of side outstanding in, prevented contacting between magnet 34 and the magnetic part 25.Thus, can make armature 22 and magnet 34 axially more approaching.Therefore, can further improve the drive efficiency of brushless motor 11.In addition, the second lower surface 322 is arranged in the radial outside of the first lower surface 321 and at least one party of radially inner side gets final product.
As shown in Figure 7, the inner peripheral surface of the outer peripheral face of substrate protuberance 52 and wheel hub protuberance 62 across the first gap 81 at diametrically contraposition.The liquid level 410 of lubricating fluid 41 is towards inner space 83 that outer peripheral face, wheel hub protuberance 62 and endless member 33 by the upper surface of substrate protuberance 52, sleeve 23 surround.And, between the space outerpace of inner space 83 and brushless motor 11, have in the first radially narrow than inner space 83 gap 81.Thus, having suppressed gas passes in and out between the space outerpace of inner space 83 and brushless motor 11.Consequently, suppressed the evaporation of lubricating fluid 41.
If suppressed the evaporation of lubricating fluid 41, then the rotational resistance at Bearning mechanism 4 places is not easy to increase.And the axial interval that armature 22 and magnet are 34 is more stable.Therefore, brushless motor 11 is rotated more efficiently.That is, compare with the situation of the structure that is not provided for suppressing lubricating fluid 41 evaporations, improved the drive efficiency of brushless motor 11.
On the other hand, as shown in Figure 6, the peripheral part of the tubular face of substrate parts 21 55 and the plectane section 71 of rotor yoke 35 across the second gap 82 at diametrically contraposition.In this brushless motor 11, the interval d1 radially in the first gap 81 is less than the interval d2 radially in the second gap 82.Thus, further suppressed the turnover of the gas at 81 places, the first gap.Therefore, further suppressed the evaporation of lubricating fluid 41.
The interval d1 radially in preferred the first gap 81 for example is below the 0.2mm.And in order further to suppress the turnover of the gas at 81 places, the first gap, the interval d1 radially in preferred the first gap 81 is below the 0.15mm.
And in the present embodiment, the axial length h1 in the first gap 81 shown in Figure 7 is longer than the axial length h2 in the second gap 82 shown in Figure 6.Thus, further suppressed the turnover of the gas at 81 places, the first gap.
And, as shown in Figure 7, in the present embodiment, dispose endless member 33 at the radially inner side of wheel hub protuberance 62.And the liquid level 410 of lubricating fluid 41 is positioned at the position of more leaning on radially inner side than endless member 33.And the first gap 81 is positioned at the position of leaning on radial outside than the outer peripheral face of endless member 33.Thus, enlarged distance from the liquid level of lubricating fluid 41 to the first gap 81.Consequently, further suppressed the evaporation of lubricating fluid 41.
Only otherwise produce contradiction, the key element in above preferred implementation and the variation can be carried out appropriate combination.
Preferred implementation of the present invention according to the above description can think that the distortion and the change that do not exceed to those skilled in the art scope and spirit of the present invention are obvious.Therefore scope of the present invention is also determined by these claims uniquely.
Fig. 9 is the partial, longitudinal cross-sectional of the related brushless motor 11B of a variation.In the example of Fig. 9, magnetic part 25B is embedded in the circuit board that consists of armature 22B.Namely.The lower surface of magnetic part 25B is positioned at than the upper surface of the circuit board that the consists of armature 22B position of side on the lower.The axial width that can suppress thus, magnetic part 25B and armature 22B integral body.Therefore, can make brushless motor 11B in axially further slimming.
In addition, magnetic part and armature also can be formed by the parts of split, and magnetic part is configured in the position of leaning on radially inner side than the peripheral part of armature.
Figure 10 is the partial, longitudinal cross-sectional of the related brushless motor 11C of other variation.In the example of Figure 10, leaning on the position configuration of radially inner side that yoke protuberance 72C is arranged than wheel hub protuberance 62C.Therefore, between substrate protuberance 52C and yoke protuberance 72C, be provided with the first gap 81C.That is, the inner peripheral surface of the outer peripheral face of substrate protuberance 52C and yoke protuberance 72C across the first gap 81C at diametrically contraposition.
Thus, can prevent that wheel hub protuberance 62C is shifted towards radially inner side owing to applied pressure when tie-down yoke protuberance 72C.Therefore, can prevent that also endless member 33C is shifted towards radially inner side.Be shifted towards radially inner side if prevented endless member 33C, then near the liquid level 410C of lubricating fluid 41C, can determine accurately the interval radially of sleeve 23C and endless member 33C.
But, be not easy to produce on the deviation this point at the interval radially in the first gap 81, preferably shown in above-mentioned the second execution mode, between the inner peripheral surface of the outer peripheral face of substrate protuberance 52 and wheel hub protuberance 62, the first gap 81 is set.
And brushless motor of the present invention also can be axle and belongs to stationary part, and sleeve belongs to the motor of the so-called fixed shaft type of rotating part.And brushless motor of the present invention and disk drive device also can be used for making for example optical disk rotary of disk dish in addition.
And, also can be different from the shape shown in each figure of the application about the shape at the detailed position of each parts.
And each key element that occurs in above-mentioned execution mode or the variation also can be carried out appropriate combination in the scope that does not produce contradiction.

Claims (14)

1. brushless motor, it comprises:
Stationary part; And
Rotating part, it can rotate with respect to described stationary part by Bearning mechanism,
Described stationary part comprises:
Tabular armature, it is at the radial outside edge of described Bearning mechanism and the Directional Extension of the central axis quadrature of upper downward-extension;
Substrate parts, it supports described armature; And
Tabular magnetic part, it contacts with the upper surface of described armature and this magnetic part surrounds described central axis, and described rotating part comprises:
Wheel hub, it comprises as the top plate portion of magnetic and from the wheel hub protuberance as magnetic of described top plate portion towards the below extension; And
Magnet, it is fixed in described wheel hub, and opposed with the upper surface of described armature,
Described armature comprises a plurality of coil pattern along circumferential array,
The peripheral part of described magnetic part is disposed at than the outer peripheral face of described magnet and the described coil pattern position by radial outside.
2. brushless motor according to claim 1,
Described armature is the circuit board that comprises described coil pattern,
Described magnetic part is the parts with described circuit board split,
Described magnetic part is expanded in the upper surface both sides' of the upper surface of described substrate parts and described circuit board scope.
3. brushless motor according to claim 1,
Described armature is the circuit board that comprises described coil pattern,
Described magnetic part is embedded in described circuit board.
4. the described brushless motor of each claim in 3 according to claim 1,
Described wheel hub comprises:
The first lower surface, it contacts with the upper surface of described magnet; And
The second lower surface, it is arranged at least one party of radial outside and the radially inner side of described the first lower surface,
Described the second lower surface is positioned at than described the first lower surface position of side on the lower,
The lower surface of described magnet is positioned at than described the second lower surface position of side on the lower,
Between described the second lower surface and described magnet, have binding agent.
5. the described brushless motor of each claim in 3 according to claim 1,
The minimum value of the distance between the lower surface of described magnet and the upper surface of described magnetic part is larger than the minimum value of the distance between the upper surface of the lower surface of described magnet and described coil pattern.
6. the described brushless motor of each claim in 3 according to claim 1,
Described magnetic part be circular and with described central axis arranged coaxial.
7. the described brushless motor of each claim in 3 according to claim 1,
Described Bearning mechanism comprises lubricating fluid between the parts of the parts of described stationary part side and described rotating part side,
At least one party in described stationary part and the described rotating part comprises the dynamic pressure groove row, and described dynamic pressure groove row are used for producing axial dynamic pressure at described lubricating fluid.
8. disk drive device, it comprises:
The described brushless motor of each claim in the claim 1 to 7;
Access section, its dish that is supported by the described rotating part of described brushless motor is carried out reading of information and write at least one party; And
Outer cover,
Described rotating part and described access section are contained in the inside of the housing that is made of described substrate parts and described outer cover.
9. brushless motor, it comprises:
Stationary part; And
Rotating part, it can rotate with respect to described stationary part by Bearning mechanism,
Described stationary part comprises:
Tabular armature, it is at the radial outside edge of described Bearning mechanism and the Directional Extension of the central axis quadrature of upper downward-extension; And
Substrate parts, it supports described armature,
Described rotating part comprises:
Wheel hub, it comprises as the top plate portion of magnetic and from the wheel hub protuberance as magnetic of described top plate portion towards the below extension;
Magnet, the upper surface of itself and described armature is opposed; And
Rotor yoke, the lower surface of itself and described armature is opposed,
Described Bearning mechanism comprises lubricating fluid between the parts of the parts of described stationary part side and described rotating part side,
At least one party in described stationary part and the described rotating part comprises the dynamic pressure groove row, and described dynamic pressure groove row are used for producing dynamic pressure at described lubricating fluid,
Described substrate parts comprises:
Base plate, it is at the downside edge of described armature and the Directional Extension of described central axis quadrature;
Substrate protuberance cylindraceous, its than described wheel hub protuberance by the position of radially inner side from described base plate towards above extend; And
The tubular face, it is positioned at the radial outside of described rotor yoke,
The liquid level of described lubricating fluid is positioned at than the position of described wheel hub protuberance by radially inner side,
Described rotor yoke is fixed in described wheel hub protuberance,
The outer peripheral face of the outer peripheral face of described substrate protuberance and described wheel hub protuberance or described substrate protuberance and described rotor yoke across the first gap at diametrically contraposition,
The peripheral part of described tubular face and described rotor yoke across the second gap at diametrically contraposition,
The interval radially in described the first gap is less than the interval radially in described the second gap.
10. brushless motor according to claim 9,
The axial length in described second gap of axial Length Ratio in described the first gap is long.
11. brushless motor according to claim 9,
The inner peripheral surface of the outer peripheral face of described substrate protuberance and described wheel hub protuberance across described the first gap at diametrically contraposition.
12. the described brushless motor of each claim in 11 according to claim 9,
Described rotating part also has the endless member of the radially inner side that is positioned at described wheel hub protuberance,
The described liquid level of described lubricating fluid is positioned at than the position of described endless member by radially inner side,
Described the first gap is positioned at the position of leaning on radial outside than the outer peripheral face of described endless member.
13. the described brushless motor of each claim in 11 according to claim 9,
Being spaced apart below the 0.2mm radially in described the first gap.
14. a disk drive device, it comprises:
The described brushless motor of each claim in the claim 9 to 13;
Access section, its dish that is supported by the described rotating part of described brushless motor is carried out reading of information and write at least one party; And
Outer cover,
Described rotating part and described access section are contained in the inside of the housing that is made of described substrate parts and described outer cover.
CN201310090813XA 2012-03-30 2013-03-21 Brushless motor and disc driving apparatus Pending CN103368347A (en)

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US9318928B2 (en) 2012-04-03 2016-04-19 Nidec Corporation Brushless motor, disk drive apparatus and brushless motor manufacturing method

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US9667108B2 (en) 2012-05-22 2017-05-30 Nidec Corporation Brushless motor and disk drive apparatus

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SG193667A1 (en) 2013-10-30

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