DE102008035509A1 - Magnetic axial bearing for initiating axial force, has bearing part provided with permanent magnet and flux guide elements provided on opposing end faces of magnet, and other elements provided at mutual spacing with respect to each other - Google Patents

Abstract

The bearing (22) has a bearing part (24) consisting of a permanent magnet (26) and two flux guide elements which are provided on opposing end faces of the permanent magnet and aligned substantially radial and perpendicular to a rotational axis. A bearing part (30) comprises two flux guide elements provided at mutual spacing with respect to each other and aligned substantially radial and perpendicular to the rotational axis. The bearing parts are made of a ferromagnetic material, and are concentric to the rotational axis. An independent claim is also included for a spindle motor comprising a stationary motor component and a rotatable motor component.

Description

Field of the invention

The The invention relates to a spindle motor with a magnetic thrust bearing according to the preamble of claim 1. A such spindle motor may preferably be for driving a hard disk drive be used.

State of the art

to Drehlagerung of electric motors of small size up to about 30 mm outside diameter, such as spindle motors, as for example in disk drives with a disk diameter of 2.5 inches, 1 inch or less or for driving small fans are used, it is known magnetic thrust bearing for receiving the to use axial forces. For spindle motors of in Speech type, preferably brushless, electronic Commutated DC motors are formed, the motor shaft coupled with a hub that holds one or more Hard disks are used. A rotor magnet is connected to the hub and arranged coaxially with a stator.

In the US 6,172,847 B1 For example, a hard disk drive is described in which a shaft is connected to a rotor hub which carries the hard disk and is coupled to the rotor. The shaft is guided in a bearing sleeve, wherein between the bearing sleeve and the shaft, a hydrodynamic radial bearing and an axial thrust bearing are formed. The axial thrust bearing is biased by magnetic elements to reduce start-up torque.

The Application, theory and calculation of magnetic bearings was in the Literature extensively dealt with. There is no doubt that Magnetic bearings, in particular with regard to reducing the bearing friction are useful. The main problem of passive magnetic bearings is the need for stabilization systems for at least one degree of freedom, because magnets alone are not able to keep a warehouse in a stable equilibrium. It is thus not possible to create stable bearings only with permanent magnets. For the so-called magnetic levitation Therefore one needs additional stabilization systems. In the prior art, this has been numerous solutions proposed.

The U.S. Patent 5,541,460 describes a spindle motor with passive magnetic thrust bearings and a track roller bearing, which can be realized as a hydrodynamic bearing or ball bearings. The passive magnetic thrust bearing generates an attractive force in the axial direction as an abutment to the track tip bearing. A similar prior art is also in the U.S. Patent 5,561,335 and in that U.S. Patent 5,545,937 described.

The US 2003/0042812 A1 describes a passive magnetic bearing for a horizontal shaft with levitation and stabilization elements. The levitation element consists of a pair of stationary bent ferromagnetic segments which lie within an annular, radially acting magnet arrangement. The magnet assembly is disposed on the inner circumference of a hollow shaft. The attractive force between the arcuate segments and the magnet assembly acts vertically to lift the shaft and horizontally to center the shaft. The stabilizing element consists of an annular Halbach magnetic arrangement and a stationary annular circuit disposed within the Halbach arrangement. The Halbach arrangement is positioned on the inner circumference of the hollow shaft. A repulsive force between the Halbach assembly and the circuit increases in inverse proportion to the radial distance therebetween and thus acts as a restoring force to bring the shaft into an equilibrium state when it has been moved out of it. The bearing is configured to generate alternating currents between the magnetic and ferromagnetic components that generate corresponding losses.

The US 2003/0117031 A1 describes a magnetic bearing for a spindle motor with a magnetic component mounted between the base plate and the motor spindle. The magnet component includes inner and outer magnet portions that are coaxially disposed and repel each other so that the spindle floats and mechanical friction is minimized. The magnetic bearing is arranged in a stationary shaft for supporting a rotating spindle, wherein the tip of the spindle is supported by a counterpart of the base plate.

The US 2004/0046467 A1 describes a magnetic bearing assembly with passive (axial) magnetic thrust bearings and with radial plain bearings or ball bearings for a rotor motor.

Summarized the prior art discloses magnetic bearings with stabilization systems, which include: steel or diamond thrust bearings based on ball bearings; magnetic fluid bearings; Eddy current elements; Plain bearing as axial Thrust bearings; as well as hybrid passive magnetic bearings that are combined with hydro- or fluid dynamic bearings or air bearings.

Disclosure of the invention

Of the Invention is based on the object, a spindle motor with a specify magnetic thrust bearing, both at startup as also works in stable operation with low friction and especially for use in hard disk drives with low Current consumption is suitable.

These Task is achieved by a spindle motor with the features of claim 1 solved.

preferred Embodiments and advantageous features of the invention are in specified in the dependent claims.

According to the invention discloses a spindle motor having a stationary engine component, the stator, and a rotatable motor component, the rotor has, and a fluid dynamic radial bearing for pivotal mounting of the rotor with respect to the stator about a rotation axis, wherein a bearing gap formed between parts of the rotor and parts of the stator and filled with a bearing fluid. Furthermore, the electric motor comprises a magnetic thrust bearing with a first bearing component and a second bearing member, which are opposite in the radial direction. To drive the electric motor is an electromagnetic drive system provided that a arranged on the fixed motor component stator assembly and a rotor magnet arranged on the rotatable motor component having.

Of the Spindle motor according to the invention with magnetic Thrust bearing is more common than conventional spindle motors Type, with fluid dynamic thrust bearings, axial ball bearings or tail tip bearings are the advantage of that the magnetic thrust bearing compared the total bearing friction to the above-mentioned arrangements of the prior art is reduced. Due to the reduced friction needed the spindle motor has a lower drive power and thus has one Up to 30% lower power consumption than spindle motors Design type. Such a spindle motor is therefore very suitable for use in hard disk drives with low power consumption or other energy-efficient drives. Furthermore, the starting friction is reduced compared to a spindle motor with axial plain bearing, there in the idle state of the motor no touching axial Storage areas are available.

The first bearing component of the thrust bearing consists of at least one Permanent magnet and at least two associated with this Flussleitstücken, on opposite faces of the permanent magnet arranged and substantially radially and perpendicular to the axis of rotation are aligned. The thrust bearing comprises a second bearing component with a flux concentrator containing at least two flux guides which is arranged at a mutual distance and substantially are aligned radially and perpendicular to the axis of rotation, each Flussleitstück the second bearing component a Flussleitstück is associated with the first bearing component and this separated by an air gap in the radial direction is directly opposite.

The stationary engine component of the electric motor comprises one in one Base plate mounted bearing bush, wherein the first bearing component of the magnetic thrust bearing preferably on an outer periphery the bearing bush is arranged. The rotatable engine component includes a shaft rotatably mounted in the bearing bush and a with the hub connected to the shaft, wherein the second bearing member of the thrust bearing on an inner circumference of the hub or one connected to the hub Component is arranged and surrounds the first bearing component.

Naturally Both bearing components of the magnetic thrust bearing also be reversed, so that the first bearing component of the thrust bearing on the inner circumference of the hub and the second bearing component of the thrust bearing are arranged on the outer circumference of the bearing bush.

In a first embodiment of the spindle motor is the Permanent magnet of the first bearing component of the thrust bearing annular formed and has first and second end faces as well inner and outer peripheral surfaces. The permanent magnet is preferably unipolar in the direction of the axis of rotation axially magnetized and arranged concentrically to the axis of rotation. One annular flux guide is on the first End face and the other annular flux guide arranged on the second end face of the permanent magnet. The flux guides have radially inner and radially outer Circumferential surfaces. Preferably, the radial inner and radially outer peripheral surfaces the flux guides on the radially inner or radially outer peripheral surface of the permanent magnet protrude. The flux conductors can either be an integral part of the bearing bush, you can but also be made as separate components. In any case the flux guides made of a ferromagnetic material, for example in the form of sheet metal rings, be formed.

The second bearing component of the axial bearing is annular in a preferred embodiment and is opposite to the first bearing component in the radial direction. The second bearing component may be formed identically to the first bearing component, that is to say comprise an annular permanent magnet magnetized in the direction of the axis of rotation, on whose end faces in each case flux guide pieces are attached are orders. The flux guide pieces of the second bearing component may protrude beyond the radially inner or radially outer peripheral surface of the permanent magnet of the second bearing component and lie directly radially opposite the corresponding flux guide pieces of the first bearing component. The opposing flux guides of the first and second bearing members form flux concentrators by their design, concentrating and concentrating the magnetic flux generated by the permanent magnet (s). As a result, the axial force to be absorbed by the thrust bearing is increased.

According to one Another preferred embodiment of the invention, the second Bearing component of the thrust bearing made of a ferromagnetic material exist and be arranged concentrically to the axis of rotation. in this connection it is preferred if the flux guide integral Part of the second bearing component are. Preferably, this has second bearing component in the region of the flux guide its largest Outside or smallest inside diameter. Unless the Fluxing the bearing components designed as individual elements These are preferably made of a ferromagnetic material. Each flux guide preferably consists of an annular Sheet metal part, this sheet metal part made of solid material or from a Stack of thin sheets can exist in the axial Direction, ie stacked in the direction of the axis of rotation. The sheet stack of each flux guide is therefore preferred built from laminated sheets. By using a sheet pile as a flux guide and by a unipolar axially magnetized Permanent magnet can avoid eddy currents be so that no eddy current losses occur. The fat the flux guide is preferably substantially lower as the thickness of the permanent magnet.

According to the invention the first and / or the second bearing component of the thrust bearing also comprise two or more annular permanent magnets, which lie one above the other in the axial direction and in opposite directions are magnetized. Between the several permanent magnets as well on the end faces of each outer Permanent magnets are then flux guides of the arranged as described above.

in the According to the invention, it does not matter if the first bearing component the thrust bearing on the stationary engine component and the second bearing component of the Axial bearing is arranged on the rotatable motor component, or the reverse case is preferred, in which the first bearing component on the rotatable engine component and the second bearing component on the fixed Motor component of the spindle motor is arranged.

The occurring between the rotor component and the stator component radial Forces are through the radial bearings described above known design, preferably fluid dynamic radial bearings recorded. The two radial bearings, are opposed by each other Bearing surfaces of the shaft and the bearing bush formed, wherein the bearing surfaces are separated by a bearing gap. According to the invention, the storage system of the spindle motor closed on one side, wherein the open end of the bearing gap by a sealing gap is sealed. The sealing gap is through a bearing fluid filled with the connecting gap Bearing gap connected and preferably in the course of the bearing gap considered for bearing opening between a radially to inside facing surface of the bearing bush and a this opposite with a lower inclination relative to the axis of rotation radially inwardly directed lateral surface the hub or a stop locking arranged. It forms conical capillary sealing gap between the inner wall of the Hub and the stopper ring and the opposite outer wall the bearing bush, which is at least partially filled with bearing fluid is. The sealing gap is substantially parallel to the bearing gap and approximately parallel to the axis of rotation of the bearing.

The Hub of the spindle motor can be formed one or more parts. A bearing component of the thrust bearing can also be used as part of Hub be formed.

Around To prevent the rotatable engine component in the axial Direction too much relative to the stationary engine component shifts, is preferably at one end of the shaft a stopper ring arranged, one arranged in the bore of the bearing bush Axially opposite the step and abutting the step, if the shaft is an excessively large performs axial movement.

alternative can at the hub, preferably above a bearing component of the Axiallagers be arranged a stopper ring, the one on the outer circumference the bearing bush arranged axially opposite step. Since the hub is connected to the shaft, so too can an excessive axial play of the shaft can be prevented in the bearing bush.

following the invention is based on preferred embodiments described in more detail with reference to the drawings.

Brief description of the drawings

1 shows a section through a first embodiment of a spindle motor according to the invention with magnetic thrust bearing.

2 shows a section through a second embodiment of a spindle motor according to the invention with magnetic thrust bearing.

Description of preferred Embodiments of the invention

1 shows a section through a spindle motor of the invention design. The spindle motor comprises a base plate 10 , which has an opening in which a bearing bush 12 is attached. The bearing bush 12 has a central bearing bore, in which a shaft 14 is rotatably mounted. Between the outer circumference of the shaft 14 and the inner circumference of the bore in the bearing bush 12 there remains a bearing gap 16 of a few microns width filled with a bearing fluid. To escape the bearing fluid from the bearing gap 16 To prevent, the bearing gap on one side by a cover plate 18 closed in a recess of the bearing bush 12 arranged and attached. On the cover plate 18 or the opposite end of the shaft 14 can spiral, radially inwardly pumping grooves for axial bearing or for expulsion of itself in the gap below the shaft 14 accumulating air can be arranged. The gap distance between shaft 14 and cover plate 18 is relatively small and is for example 60 microns. The other side of the bearing gap 16 is via an annular connecting gap 26 with a sealing gap 28 connected. The sealing gap 28 is formed as a conical capillary seal, which is approximately in the axial direction between an outer circumferential surface of the bearing bush 12 and an opposite inner circumferential surface of an annular member 20 (Stopperring) is arranged. The connecting gap 26 is about an order of magnitude wider than the bearing gap, for example 40 microns. In the area of the connecting gap 26 can additionally pump structures 50 be provided to compensate for the centrifugal forces acting on the bearing fluid. These pump structures 50 are on the end face of the bearing bush 12 or the opposite surface of a hub 22 arranged and form a kind of pumping seal to support the sealing effect of the sealing gap 28 , The pump structures 50 create a pumping action into the interior of the bearing in the direction of the bearing gap 16 ,

The hub 22 is with the free end of the shaft 14 connected. The rotary bearing of the shaft 14 in the bearing bush 12 is due to two fluid dynamic radial bearings 24a and 24b achieved, which are characterized by fishbone-shaped bearing structures on the bearing surfaces. In principle, the radial bearings can also be designed as Mehrflächengleitlager or grooveless plain bearings. To prevent excessive axial movement of the shaft 14 in the bearing bush 12 Preventing is at a stage of an approach of the hub 22 a stopper ring 20 arranged. The stopper ring 20 limits the sealing gap 28 and is one on the front side of the bearing bush 12 provided federal government 12a axially opposite. The stopper ring 20 and comes across this covenant 12a as soon as the wave 14 performs an excessive axial movement upwards. The stopper ring 20 consists of non-magnetic or weak magnetic material.

The axial forces acting on the shaft 14 act through a magnetic thrust bearing 36 taken, which from a first bearing component 38 and a second bearing component 44 consists. The first bearing component 38 is in 1 radially inward of the second bearing component 44 at a step on the outer circumference of the bearing bush 12 arranged. The first bearing component 38 comprises an annular and concentric with the axis of rotation 30 arranged permanent magnets 40 , for example from NdFeB or SmFeN. On the faces of the permanent magnet 40 are two annular flux guides 42a . 42b arranged, which preferably consist of a radially anisotropic ferromagnetic sheet having a thickness of, for example, 0.2 mm or from a sheet stack. The permanent magnet 40 is in the axial direction, ie in the direction of the axis of rotation 30 single-pole (unipolar) or multi-pole (multipolar) magnetized. Thus the bearing bush 12 If possible, the magnetic flux does not short-circuit it, and possibly also the wave 14 preferably of nonmagnetic material or of weak magnetic steel having a magnetic permeability of less than 100.

The second bearing component 44 includes in this embodiment an annular on the hub 22 trained approach, the two defined, preferably integrally formed Flussleitstücke 46a . 46b forming, in the radial direction opposite the Flussleitstücken 42a and 42b of the first bearing component 38 are arranged. The flux guides 42a and 42b preferably have a slightly larger outer diameter than the permanent magnet 40 , Likewise, the Flussleitstücke form 46a and 46b of the second bearing component 44 a Flußkonzentrator with annular zones and define the smallest inner diameter of the second bearing component 44 , The respective opposite flux guide of the first and second bearing member are through an air gap 48 separated from each other. The of the permanent magnet 40 of the first bearing component 38 outgoing magnetic field lines are in the Flussleitstücken 42a and 42b concentrated and in the radial direction across the air gap 48 and the flux guides 46a and 46b of the second bearing component 44 to the permanent magnet 40 recycled. Once the wave 14 and the hub 22 relative to the bearing bush 12 and the base plate 10 be deflected in the axial direction, generates the interaction of the permanent magnet 40 so like the flux guides 42a . 42b and the flux guides 46a and 46b the opposing bearing member a restoring force in the axial direction, which holds the rotatable motor component relative to the stationary engine component in the axial direction in a stable state of suspension. The hub 22 , at the second bearing part 44 is formed, preferably consists of a ferromagnetic material, such as steel.

The electromagnetic drive system of the spindle motor is formed by one on the base plate 10 fixed stator arrangement 32 , which radially outward on the hub 22 arranged rotor magnet 34 opposite. Since the hub is magnetic, eliminates a separate yoke ring for the rotor magnet.

In the spindle motor according to the invention with a magnetic thrust bearing, the friction losses in the bearing system are considerably reduced because of an axial thrust bearing of conventional design can be completely dispensed with and instead a magnetic thrust bearing 36 is used, which works without friction. Further, since no axial fluid dynamic bearings are used, the axial portions of the fluid gap can be made correspondingly large, thereby reducing the friction losses here as well. This means that the axial bearing gaps of about 10 micrometers so far can be increased to at least twice to three times, so 20-30 microns or even four times, so 40 microns or more. The magnetic bearing also acts at a standstill of the bearing system in a corresponding manner, in contrast to, for example, a fluid dynamic thrust bearing in which a corresponding axial erection ("fly height") of the thrust bearing due to the formation of an axially acting pressure pad only during operation, ie at rotation of the Warehouse, stops.

When assembling the spindle motor, the shaft is first 14 in the opening of the hub 22 pressed or glued and at right angles to the hub 22 aligned. Then the lower opening of the bearing bush 12 with the cover plate 18 locked. The cover plate 18 For example, with the bushing 12 welded or glued. The one-sided closed bearing bush is then on the shaft 14 attached. Then the stopper ring 20 at the hub 22 attached, so that the shaft 14 no longer from the bushing 12 can slip out. By suitable and known from the prior art method now bearing fluid over the sealing gap 28 in the camp, so the bearing gap 16 and the connection gap 26 filled. Thereafter, the gap distance of the connection gap 26 adjusted by a corresponding adjusting device and the thrust bearing 36 assembled. The first bearing part 38 of the thrust bearing 26 is attached to the bearing bush and fixed with adhesive. The adhesive serves as a lubricant, so that the first bearing part 38 due to the axial magnetic forces by itself with respect to the second bearing part 44 Align axially before the adhesive hardens.

2 shows a second embodiment of a spindle motor according to the invention. In 2 are the same components with the same reference numerals as in 1 denotes, wherein the corresponding reference numerals have been preceded by a "1". In contrast to 1 shows the wave 114 at her the cover plate 118 adjacent end a stopper ring 120 on, in a recess of the bearing bush 112 is arranged. The stopper ring 120 one lies through the bearing bush 112 opposite level formed and abuts this stage as soon as the shaft 114 performs an excessive axial movement. The bearing gap 116 is over the connecting gap 126 with the sealing gap 128 connected. The sealing gap 128 is limited by an outer surface of the bearing bush 112 and an inner circumferential surface of an annular projection of the hub 122 , The second bearing component 144 the thrust bearing is also on the annular shoulder of the hub 122 arranged.

In the bearing bush 112 is optional a recirculation channel 152 provided, which as oblique to the axis of rotation 130 extending bore in the bearing bush 112 is trained. This recirculation channel 152 connects the lower part of the bearing, ie the section of the bearing gap in the area of the stop locking 120 with the connection gap 126 and ensures a uniform circulation of the bearing fluid in the bearing gap and for a pressure equalization - in particular at the shaft end - within the fluid bearing.

10 110

baseplate

12 112

bearing bush

12a

Federation

14 114

wave

16 116

bearing gap

18 118

cover

20 120

stopper ring

22 122

hub

24a, 24b

radial bearings

124a, 124b

26 126

communication gap

28 128

seal gap

30 130

axis of rotation

32 132

stator

34 134

rotor magnet

36 136

thrust

38 138

first bearing component

40 140

permanent magnet

42a, 42b

flux conductor

142a, 142b

44 144

second bearing component

46a 46b

flux conductor

146a, 146b

48 148

air gap

50, 150

pumping structures

52 152

recirculation

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - US 6172847 B1 [0003]
• US 5541460 [0005]
• US 5561335 [0005]
• US 5545937 [0005]
• US 2003/0042812 A1 [0006]
• US 2003/0117031 A1 [0007]
• US 2004/0046467 A1 [0008]

Claims (23)

Spindle motor, comprising: a stationary engine component ( 10 . 12 ; 110 . 112 ), a rotatable engine component ( 14 . 22 ; 114 . 122 ), at least one fluid dynamic radial bearing ( 24a . 24b ; 124a . 124b ) for the rotary mounting of the rotatable engine component ( 14 . 22 ; 114 . 122 ) with respect to the stationary engine component ( 10 . 12 ; 110 . 112 ) about a rotation axis ( 30 . 130 ), wherein a bearing gap ( 16 ; 116 ) between parts of the rotatable and parts of the stationary engine component and is filled with a bearing fluid, and a magnetic thrust bearing ( 36 ; 136 ) with a first bearing component ( 38 ; 138 ) and a second bearing component ( 44 ; 144 ) which are opposed in the radial direction, and an electromagnetic drive system with a stator arrangement arranged on the stationary motor component (US Pat. 32 ; 132 ) and a rotor magnet arranged on the rotatable motor component ( 34 ; 134 ). Spindle motor according to claim 1, characterized in that the stationary engine component ( 10 . 12 ; 110 . 112 ) one in a base plate ( 10 ; 110 ) fixed bearing bush ( 12 ; 112 ), and the first bearing component ( 38 ; 138 ) of the thrust bearing ( 36 ; 136 ) on an outer circumference of the bearing bush ( 12 ; 112 ) is arranged. Spindle motor according to claim 1 or 2, characterized in that the rotatable motor component ( 14 . 22 ; 114 . 122 ) one in the bearing bush ( 12 ; 112 ) rotatably mounted shaft ( 14 ; 114 ) and a hub connected to the shaft ( 22 ; 122 ), and the second bearing component ( 44 ; 144 ) of the thrust bearing ( 36 ; 136 ) on an inner circumference of the hub or one with the hub ( 22 ; 122 ) is arranged connected component and the first bearing component ( 38 ; 138 ) radially surrounds. Spindle motor according to one of claims 1 to 3, characterized in that the first bearing component ( 38 ; 138 ) of the thrust bearing at least one permanent magnet ( 40 ; 140 ) and at least two flux guides ( 42a . 42b ; 142a . 142b ) disposed on axially opposite end faces of the permanent magnet and aligned substantially radially and perpendicular to the axis of rotation, and the second bearing component ( 44 ; 144 ) at least two flux guides ( 46a . 46b ; 146a . 146b ) arranged at a mutual axial distance and aligned substantially radially and perpendicular to the axis of rotation, wherein each flux guide ( 46a . 46b ; 146a . 146b ) of the second bearing component a flux guide ( 42a . 42b ; 142a . 142b ) is associated with the first bearing component and this separated by an air gap ( 48 ; 148 ) is directly opposite in the radial direction. Spindle motor according to one of claims 1 to 4, characterized in that the permanent magnet ( 40 ; 140 ) of the first bearing component ( 38 ; 138 ) Is annular and has first and second end faces and radially inner and radially outer peripheral surfaces. Spindle motor according to one of claims 1 to 5, characterized in that the permanent magnet ( 40 ; 140 ) of the first bearing component ( 38 ; 138 ) axially in the direction of the axis of rotation ( 30 ; 130 ) is magnetized. Spindle motor according to one of claims 1 to 6, characterized in that the annular flux guide pieces ( 42a . 42b ; 142a . 142b ) on the axial end faces of the permanent magnet ( 40 ; 140 ) are arranged and radially inner and radially outer peripheral surfaces which extend beyond the radially inner or radially outer peripheral surface of the permanent magnet ( 40 ; 140 ) protrude. Spindle motor according to one of claims 1 to 7, characterized in that the flux guide pieces ( 42a . 42b ; 142a . 142b ) consist of a ferromagnetic material. Spindle motor according to one of claims 1 to 8, characterized in that the second bearing component ( 44 ; 144 ) comprises at least one permanent magnet having first and second end surfaces and radially inner and radially outer peripheral surfaces. Spindle motor according to claim 9, characterized in that the permanent magnet of the second bearing component ( 44 ; 144 ) in the direction of the axis of rotation ( 30 ) is axially magnetized. Spindle motor according to one of claims 9 to 10, characterized in that annular flux guides on the end faces of the permanent magnet of the second bearing component ( 44 ; 144 ) are arranged and radially inner and radially outer peripheral surfaces which protrude beyond the radially inner or radially outer peripheral surface of the permanent magnet of the second bearing member. Spindle motor according to one of claims 1 to 11, characterized in that the second bearing component ( 44 ; 144 ) is annular and the first bearing component ( 38 ; 138 ) is opposite in the radial direction. Spindle motor according to one of claims 1 to 12, characterized in that the second bearing component ( 44 ; 144 ) consists of a ferromagnetic material and concentric with the axis of rotation ( 30 ; 130 ) is arranged. Spindle motor according to one of claims 1 to 13, characterized in that the flux guide pieces ( 46a . 46b ; 146a . 146b ) integral part of the second bearing component ( 44 ; 144 ) are. Spindle motor according to one of claims 1 to 14, characterized in that the second bearing component ( 44 ; 144 ) in the region of the flux guide pieces ( 46a . 46b ; 146a . 146b ) has its largest or smallest diameter. Spindle motor according to one of claims 1 to 15, characterized in that the flux guide pieces ( 46a . 46b ; 146a . 146b ) consist of a ferromagnetic material. Spindle motor according to one of claims 1 to 16, characterized in that the flux guides of the first and / or second bearing component consist of a sheet stack, whose plates are superimposed in the axial direction. Spindle motor according to one of claims 1 to 17, characterized in that at the bearing gap ( 116 ) an annular bearing fluid filled transition gap ( 126 ) connected between an end face of the bearing bush ( 112 ) and an opposite surface of the hub ( 122 ) is arranged, and at the connecting gap a substantially axially extending sealing gap ( 128 ), which between a lateral surface of the bearing bush ( 112 ) and one of these opposite lateral surface of the hub ( 122 ) is arranged and at least partially filled with bearing fluid. Spindle motor according to one of claims 1 to 18, characterized in that at the bearing gap ( 16 ) an annular bearing fluid filled connecting gap ( 26 ) connected between an end face of the bearing bush ( 12 ) and an opposite surface of the hub ( 22 ) is arranged, and at the connecting gap a substantially axially extending sealing gap ( 28 ), which between a lateral surface of the bearing bush ( 12 ) and one of these opposite lateral surface of a Stopperrings ( 20 ) is arranged and at least partially filled with bearing fluid. Spindle motor according to one of claims 1 to 19, characterized in that the stopper ring ( 20 ) at the hub ( 22 ) is arranged and arranged at one end of the bearing bush collar ( 12a ) is axially opposite. Spindle motor according to one of claims 1 to 19, characterized in that the shaft ( 114 ) at one end a stopper ring ( 120 ), which in a recess of the bearing bush ( 112 ) is arranged. Spindle motor according to one of claims 1 to 21, characterized in that on at least one of the connecting gap ( 26 . 126 ) limiting surfaces a groove structure of a pumping seal is arranged. Spindle motor according to one of claims 1 to 22, characterized in that the central axis of the sealing gap ( 28 ; 128 ) at an angle of 0 ° to 15 °, preferably 3 ° -6 ° with respect to the axis of rotation ( 30 ; 130 ) is aligned.