DE102015009752A1 - Rotor component for an electrical machine - Google Patents

Abstract

The invention relates to a rotor component (10, 110) for an electrical machine, which comprises a rotor magnet (14, 114, 214) and / or a magnetic yoke (116, 216) as part of an electromagnetic drive system. According to the invention, the rotor magnet (14, 114) or the magnetic yoke (216) has a conical or frusto-conical peripheral surface (14a, 114a3 216b) with a complementary, conical or frusto-conical peripheral surface (10a, 116a) of the rotor component (10) or the magnetic return (116) is connected, wherein the peripheral surfaces (10a, 14a, 114a, 116a, 216b) are formed such that the rotor magnet (14, 114) or the magnetic yoke (216) on the rotor component (10) or at the magnetic yoke (116) is centered and axially positioned.

Description

Field of the invention

The invention relates to a rotor component for an electrical machine, and in particular to a rotor component with a magnetic component arranged thereon, for example a permanent magnet rotor magnet.

State of the art

An electric machine in the form of a spindle motor with a generic rotor component is for example from the DE 10 2013 014 229 A1 known.

This spindle motor comprises a fixed motor component consisting of a motor flange, a bearing arranged in the motor flange bearing bush and a rotatable motor component consisting of a rotatably mounted in the bearing bush shaft, at the upper free end of a rotor component is attached. The motor shown is designed as an external rotor motor.

For driving the spindle motor, an electromagnetic drive system is provided. The drive system comprises an electric stator, which is fixedly mounted on the motor flange. At an inner edge of the rotor component, an annular rotor magnet is arranged, which is designed as a permanent magnet and has a plurality of magnetic poles distributed over the circumference.

The rotor magnet surrounds the electric stator, wherein a relatively narrow air gap of, for example, 0.2 mm remains between the outer circumference of the stator and the inner circumference of the rotor magnet.

The rotatable engine component should be arranged as concentric as possible to the fixed engine component in order to achieve the best possible performance of the engine. In particular, the air gap between the stator and the rotor magnet over the circumference should have a constant width.

If the rotatable engine component is not exactly concentric with the stationary engine component, then differences in the width of this air gap may result, for example, from several tens to a few hundred micrometers.

These differences in the width of the air gap are noticeable by disturbances in the electrical system, in particular also acoustic disturbances in the form of vibrations and acoustic interference frequencies.

It is therefore desirable to achieve the best possible concentricity between the stator and the rotor magnet.

The stator can be mounted very accurately centric, since it is fixedly arranged on the fixed engine component, for example by means of a press fit. However, the rotor magnet can not be fixed by means of a press connection on the inner circumference of the rotor component, since the magnet is usually made of a porous sintered material, which does not allow large insertion forces.

Therefore, there is a clearance fit or transition fit between the inner periphery of the rotor member and the outer circumference of the rotor magnet, the rotor magnet being fixed to the rotor member by means of adhesive. The axial positioning of the rotor magnet can be effected by means of an axial stop, which is arranged on the underside of the rotor component.

Due to the clearance fit or transition fit, there may be radial displacements of the rotor magnet relative to the rotor component, which can then lead to errors in the concentricity and an imbalance of the rotor component. Here is the invention to remedy the situation.

Disclosure of the invention

The invention has for its object to provide a rotor component for an electrical machine that allows accurate and concentric mounting of a magnetic component.

This object is achieved by a rotor component having the features of claim 1.

The rotor component for the electric machine comprises a rotor magnet and / or a magnetic yoke as part of an electromagnetic drive system.

The invention is characterized in that the rotor magnet or the magnetic yoke has a conical or frusto-conical peripheral surface, which is connected to a complementary, also conical or frusto-conical peripheral surface of the rotor component or the magnetic yoke. The peripheral surfaces are inventively designed such that the rotor magnet or the magnetic yoke is centered on the rotor component or at the magnetic yoke and axially positioned.

These conical or frusto-conical peripheral surfaces form two complementary insertion bevels, which are the insertion of the rotor magnet or the magnetic yoke into the Rotor component or the magnetic return during assembly easier.

The rotor magnet or the magnetic yoke is inserted into the rotor component or the magnetic yoke until the inclined surfaces form a joint connection in the form of a conical seat.

In this case, no press fit is provided, but the rotor magnet or the magnetic yoke is only inserted so far, to touch the facing oblique peripheral surfaces and abut each other. The fixation of the rotor magnet or the magnetic yoke is then preferably carried out by means of adhesive, which was previously applied to at least one of the two joining surfaces.

By means of these conical or frustoconical peripheral surfaces on the rotor magnet / magnetic yoke and on the rotor component / magnetic yoke, the rotor magnet or the magnetic yoke is centered very precisely in the rotor component or the magnetic yoke.

The axial position of the rotor magnet or magnetic yoke in the rotor component or in the magnetic return is also determined by the shape and the angle of the conical or frusto-conical peripheral surfaces.

An axial stop, as was provided in the prior art, is no longer necessary in the rotor component according to the invention, since otherwise a double fit would result. An axial stop would therefore be either ineffective or would limit the magnetic component too early in its axial position before the oblique peripheral surfaces abut each other. By eliminating this axial stop the rotor magnet is no longer short-circuited on this page, resulting in an increase in field strength.

The conical or frusto-conical peripheral surfaces of the rotor magnet, the magnetic yoke and the rotor component are arranged at an acute angle to a common central axis, which corresponds to the axis of rotation of the rotor component.

The angle of these peripheral surfaces is preferably the same size. In a preferred embodiment, the angle of the peripheral surfaces is between 1 ° and 10 ° degrees with respect to the axis of rotation.

In an external rotor motor, the rotor magnet or the magnetic yoke comprises a conical or frusto-conical outer peripheral surface, which cooperates with a conical or frusto-conical inner peripheral surface of the rotor component or the magnetic yoke.

In an internal rotor motor, the rotor magnet or the magnetic yoke comprises a conical or frusto-conical inner peripheral surface, which cooperates with a conical or frusto-conical outer peripheral surface of the rotor component or the magnetic yoke.

In a preferred embodiment of the invention, the rotor magnet has a concentric with the axis of rotation extending inner peripheral surface. In the case of an internal rotor motor, the rotor magnet has a concentric with the axis of rotation extending outer peripheral surface.

The rotor component according to the invention can be used in an electric motor together with a stator comprising a plurality of stator poles provided with stator windings.

Preferably, the rotor component according to the invention, together with a stator which comprises a plurality of stator poles provided with stator windings, serve as part of an electromagnetic drive system which rotates a spindle motor with a fluid dynamic bearing system. This spindle motor may preferably be used in a hard disk drive or a fan.

Hereinafter, various embodiments of the invention will be described with reference to the drawings. This results in further advantages and features of the invention.

Brief description of the drawings

1 shows a first embodiment of a rotor component and a magnetic member arranged thereon in the form of a rotor magnet.

2 shows a second embodiment of a rotor component with magnetic return and a magnetic component arranged in the form of a rotor magnet.

3 shows a third embodiment of a rotor component and a magnetic member arranged thereon in the form of a rotor magnet with magnetic inference.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

1 shows a rotor component 10 for a spindle motor, as for example in the beginning in connection with the DE 10 2013 014 229 A1 has been described. The spindle motor is designed as an external rotor motor.

The rotor component 10 has one to the axis of rotation 12 concentric bore in which a shaft (not shown) can be attached, and an outer edge, on the inner peripheral surface 10a in a known manner, an annular magnetic component in the form of a rotor magnet 14 is attached. The rotor magnet 14 extends annular over the circumference of the rotor component 10 and has a number of magnetic poles alternately around the circumference of the rotor magnet 14 are arranged.

The inner peripheral surface 10a the edge of the rotor component 10 According to the invention is tapered conical or frustoconical, so that the inner diameter of the rotor component 10 in the direction of the arrow 18 , So axially upwards in the direction of the recess for receiving the shaft, reduced. The conical or frusto-conical peripheral surface 10a of the rotor component 10 runs at an angle α with respect to the axis of rotation 12 , The angle α is an acute angle and is preferably between 1 ° and 10 °, but it may also include smaller or larger acute angles.

In the same way, the outer peripheral surface 14a of the rotor magnet 14 conical or frusto-conical shape and that at the same angle α as the inner peripheral surface 10a of the rotor component 10 , The tapered outer peripheral surface 14a of the rotor magnet 14 is therefore complementary to the tapered inner peripheral surface 10a of the rotor component 10 educated.

When mounting the rotor magnet 14 on the rotor component 10 becomes the rotor magnet 14 in the direction of the arrow 18 , ie in the direction of the decreasing inner diameter of the rotor component 10 , in the rotor component 10 inserted, wherein the beveled peripheral surface 14a of the rotor magnet 14 and the peripheral surface 10a of the rotor component 10 act as an insertion bevel and an insertion of the rotor magnet 14 facilitate. The rotor magnet 14 can now so far in the rotor component 10 be introduced until the peripheral surfaces 10a and 14a touch and a self-locking takes place. The rotor magnet 14 can not continue in the rotor component 10 and has reached its intended final position.

The rotor magnet 14 is preferably by means of adhesive in the rotor component 10 fixed on one or both of the peripheral surfaces 10a . 14a of the rotor component 10 or the rotor magnet 14 was applied before insertion.

Due to the oblique peripheral surfaces 10a and 14a results according to the invention an automatic and accurate centering of the rotor magnet 14 in the rotor component 10 in relation to the axis of rotation 12 and a defined axial end stop, which is the axial position of the rotor magnet 14 in the rotor component 10 certainly.

The inner peripheral surface 14b of the rotor magnet 14 is preferably cylindrical, ie concentric with the axis of rotation 12 educated. This has the inner peripheral surface 14b Seen over the circumference always the same distance to the axis of rotation 12 and thus also the same distance to a radially inside of the rotor magnet 14 assembled electric stator (not shown in the drawing).

Consequently, the intended air gap between the rotor magnet remains 14 and the electric stator over the circumference equal in size.

The above problems with respect to disturbances in the electrical system and acoustic disturbances due to lack of concentricity between the rotor magnet 14 and the electric stator are thus avoided.

In contrast to the prior art can in an inventive embodiment of the rotor component 10 and the rotor magnet 14 during the subsequent assembly of the rotor magnet 14 an accuracy of concentricity of a few micrometers can be achieved.

In a spindle motor, as is typically used to drive hard disk drives, has the rotor component 10 or the rotor magnet 14 for example, a diameter of 20 to 25 millimeters.

In 1 is the rotor component 10 formed, for example, of magnetic steel, so that the rotor component at the same time a magnetic yoke for the rotor magnet 14 forms.

2 shows a further embodiment of the invention, in which the rotor component 110 made of a non-magnetic material, such as. B. aluminum, consists.

Therefore, the rotor component 110 not as magnetic inference for the rotor magnet act, leaving an additional magnetic inference 116 may be provided from soft magnetic material, on the inner peripheral surface 110a of the rotor component 110 is attached. The inner peripheral surface 110a of the rotor component 110 is cylindrical, ie concentric with the axis of rotation 12 , educated.

The magnetic inference 116 For example, in the rotor component 110 pressed in and optionally additionally fixed with adhesive.

The magnetic inference 116 has cylindrical outer peripheral surface 116a and a tapered conical or frusto-conical inner peripheral surface 116a whose diameter decreases starting from the outer edge. Alternatively, both the inner and the outer peripheral surface of the magnetic yoke may be conical or frustoconical (not shown in the drawing).

The rotor magnet 114 points, as well as in 1 , a beveled outer peripheral surface which is in the form of a conical or frusto-conical peripheral surface 114a is formed and complementary to the inner peripheral surface 116a of the magnetic inference 116 is trained.

The peripheral surfaces 110a . 114a of the rotor component 110 and the rotor magnet 114 each extend at an angle α with respect to the axis of rotation 12 , wherein the angle α preferably be between 1 ° to 10 °, but could also assume other values.

The rotor magnet 114 will now with its outer peripheral surface 114a on the inner peripheral surface 116a of the magnetic inference 116 connected. For this purpose, the rotor magnet 114 in the direction of the arrow 18 , ie in the direction of the decreasing inner diameter of the magnetic yoke 116 , in the ring-shaped magnetic return 116 pushed in until the conical or frustoconical surfaces 116a and 114a create each other. In this position, the rotor magnet 114 by means of, for example, adhesive on the magnetic return path 116 fixed.

The magnetic inference 116 can be approximately rectangular or for example also approximately L-shaped in cross section, wherein an upper leg of the yoke is directed radially inwardly and the upper end face of the rotor magnet at least partially covered (not shown in the drawing). However, the rotor magnet must not strike the upper leg of the magnetic yoke. By an L-shape of the magnetic yoke, a better magnetic flux from the rotor magnet can be ensured in the magnetic yoke.

3 shows a further embodiment of the invention with magnetic return 216 that has an inner cylindrical peripheral surface 216a having, with an outer cylindrical peripheral surface 214a of the rotor magnet 214 initially firmly connected, for example by means of adhesive.

The result is a composite magnetic component, which consists of the rotor magnet 214 and the magnetic yoke attached thereto 216 exists and in the rotor component 10 is installed.

The rotor component 10 has an inner peripheral surface 10a on, obliquely in the form of a conical or frusto-conical peripheral surface 10a is trained. The peripheral surface extends at an angle α with respect to the axis of rotation 212 , wherein the angle α is preferably one degree to 10 degrees but can also assume other values.

An outer peripheral surface 216b of the magnetic inference 216 is also tapered or frusto-conical, also at an angle α.

The magnetic component consisting of the rotor magnet 214 and the magnetic yoke attached thereto 216 can now in the rotor component 10 be introduced until the sloping surfaces 10a and 216b of the rotor component 10 and the magnetic inference 216 abut each other. Then the magnetic component has 214 . 216 its end position in the rotor component 10 reaches and sits concentrically and axially positioned in the rotor component 10 ,

By means of adhesive, the magnetic component 214 . 216 in the rotor component 10 be fixed.

It should also be mentioned that the preferred rotor magnets are often formed as a molded part made of sintered material, so that the required shape with the conical or frusto-conical inclined surface can already be realized by the mold. Especially with moldings appropriate Entformungsschrägen necessary to be able to remove the molding from the mold easier. This Entformungsschrägen may be formed according to the invention as a conical or frusto-conical inclined surfaces in the required angle α.

It should also be noted that the invention can be applied not only to motors in which the rotor magnet is arranged radially outside of the electric stator, but also for motors in which the rotor magnet radially inside of the stator is arranged. This applies to both external rotor motors and internal rotor motors.

LIST OF REFERENCE NUMBERS

10, 110

rotor component

10a, 110a

inner peripheral surface

12

axis of rotation

14, 114, 214

rotor magnet

14a, 114a, 214a

outer peripheral surface

14b, 114b, 214b

inner peripheral surface

116, 216

magnetic inference

116a, 216a

inner peripheral surface

116b, 216b

outer peripheral surface

18

arrow

α

angle

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102013014229 A1 [0002, 0034]

Claims (13)

Rotor component ( 10 . 110 ) for an electric machine, which has a rotor magnet ( 14 . 114 . 214 ) and / or a magnetic inference ( 116 . 216 ) as part of an electromagnetic drive system, characterized in that the rotor magnet ( 14 . 114 ) or the magnetic inference ( 216 ) at least one conical or frusto-conical peripheral surface ( 14a . 114a . 216b ) having a complementary, conical or frusto-conical peripheral surface ( 10a . 116a ) of the rotor component ( 10 ) or the magnetic inference ( 116 ), wherein the peripheral surfaces ( 10a . 14a . 114a . 116a . 216b ) are formed such that the rotor magnet ( 14 . 114 ) or the magnetic inference ( 216 ) on the rotor component ( 10 ) or at the magnetic inference ( 116 ) is centered and positioned axially. Rotor component ( 10 . 110 ) according to claim 1, characterized in that the rotor magnet ( 14 ) and the rotor component ( 10 ) or the rotor magnet ( 114 ) and the magnetic inference ( 116 ) or the magnetic inference ( 216 ) and the rotor component ( 10 ) are connected by means of a joint connection in the form of a conical seat. Rotor component ( 10 . 110 ) according to one of claims 1 or 2, characterized in that the conical or frusto-conical peripheral surfaces ( 10a . 14a . 114a . 116a . 216b ) are interconnected by means of adhesive. Rotor component ( 10 . 110 ) according to one of claims 1 to 3, characterized in that the conical or frusto-conical peripheral surfaces ( 10a . 14a . 114a . 116a . 216b at an acute angle α to a common axis of rotation ( 12 ) of the components are arranged. Rotor component ( 10 . 110 ) according to one of claims 1 to 4, characterized in that the angles α of the conical or frusto-conical peripheral surfaces ( 10a . 14a . 114a . 116a . 216b ) are the same size. Rotor component ( 10 . 110 ) according to one of claims 1 to 5, characterized in that the angles α of the conical or frusto-conical peripheral surfaces ( 10a . 14a . 114a . 116a . 216b ) between 1 ° and 10 °. Rotor component ( 10 . 110 ) according to one of claims 1 to 6, characterized in that the rotor magnet ( 14 . 114 ) or the magnetic inference ( 216 ) a conical or frusto-conical outer peripheral surface ( 14a . 114a . 216b ) and the rotor component ( 10 ) or the magnetic inference ( 116 ) a conical or frusto-conical inner peripheral surface ( 10a . 116a ) having. Rotor component according to one of claims 1 to 6, characterized in that the rotor magnet or the magnetic yoke has a conical or frusto-conical inner peripheral surface and the rotor component or the magnetic yoke has a conical or frusto-conical outer peripheral surface. Rotor component ( 10 . 110 ) according to one of claims 1 to 8, characterized in that the inner peripheral surface ( 14b . 114b . 214b ) of the rotor magnet ( 14 . 114 . 214 ) concentric with the axis of rotation ( 12 ) runs. Electric motor with a rotor component ( 10 . 110 ) according to one of claims 1 to 9 and a stator having a plurality of stator windings provided with stator windings. Spindle motor with a rotor component ( 10 . 110 ) according to one of claims 1 to 9, a stator having a plurality of stator windings provided with stator poles and a fluid dynamic bearing system. Hard disk drive with a spindle motor according to claim 11. Fan with a spindle motor according to claim 11.

Images