FR2673776A3 - PERMANENT MAGNET ROTOR FOR ELECTRIC MACHINES. - Google Patents

Abstract

Permanent magnet rotor for electrical machines, characterized in that each upper arc-shaped edge opposite the support cylinder (10) on the end faces of the magnet segments (11) is provided with a chamfer (25, 26) and the fixing device (12) consists of two annular covers (13, 14) which are fitted on the end faces of the magnet segments (11) and protrude with an overflow edge (27, 28) suitable for each of the chamfers (25, 26) over them (25, 26) and in that the annular covers (13, 14) are fixed being axially and radially blocked on the support cylinder (10).

Description

"Permanent magnet rotor for electric machines

  The present invention relates to a permanent magnet rotor for electric machines, particularly as a submerged laundry pump element.

  fuel pump or the like, comprising a cylinder

  of support and several permanent magnet segments

  in the form of a shell applied to the support cylinder, these segments abutting each other in the circumferential direction and being held on the support cylinder,

  rotation by means of a fixing device

  tion. According to a known permanent magnet rotor, corresponding to this type (P 36 22 231 3), the device for fixing the arcuate cup shaped magnet segments consists of a sleeve coaxial with the axis of the rotor, in a non-magnetic material, and whose two end faces are each covered with a

  shrink ring on the support cylinder.

  The two closing rings are covered by the sleeve. The support cylinder consists of a steel core integral with the rotor shaft; at

  its periphery this nucleus comprises a number of.

  permanent magnet segments corresponding to the number

  grooves at the junction points of the seg-

  Permanent magnet elements The grooves and the cavities and slots formed at the junctions of the permanent magnet segments are filled with cast resin on the one hand between the permanent magnet segments and the steel core on the other hand. between the permanent magnet segments and the sleeve, resulting in manufacturing tolerances. The present invention aims to overcome the drawbacks of known solutions and concerns

  this effect a rotor of the type defined above characterized by

  characterized in that each arcuate upper edge opposite the support cylinder on the end faces of the magnet segments is provided with a chamfer and the fixing device consists of two covers

  annular tips fitted on the front faces of

  magnet parts and pass with an overflow edge adapted to each of the chamfers over them, the annular covers being fixed while being blocked

  axially and radially on the support cylinder.

  This permanent magnet rotor offers the advantage

  reduced manufacturing cost thanks to a reduced installation

  enabling a high work rate The fixing of the permanent magnet segments is also

  guaranteed even at very high speeds.

  In addition, the rotor can be used without difficulty.

  permanent magnet as rotating rotor in a humi-

  of, for example in the fuel pumps because there is no risk of swelling of the rotor as is the case of a synthetic fastening of the magnet segments.

  According to another characteristic of the in-

  the outer diameter of the annular covers

  frontal res is equal to the outer diameter of the segments

  As a result, no fastening element protrudes from the outer diameter of the magnet, which allows the production of extremely small air gaps.

in the engine.

  According to a particularly advantageous characteristic of the invention, the support cylinder

  has at both ends, each time a shoulder-

  intended for a certain distance from the ex-

  frontal trenches The axial length of the permanent magnet segments is equal to or slightly greater than the axial distance of the annular shoulders. The annular covers are fixed integrally on the end faces of the permanent magnet segments, in the axial direction and at least one annular covers is applied against an annular shoulder

by axial pressure.

  The axial tightening of the annular covers is made according to a preferred embodiment of the invention in that the support cylinder is in

  sleeve shape which protrudes axially at each ex-

  tremity relative to the permanent magnet segments

  by a collared collar and the thickness of which is

  King is reduced The annular opening, central of the

  annular covers is dimensioned lightly

  larger than the outside diameter of the collars

  of the sleeve and the axial tightening of the annular covers

  res is ensured by locking the collar ends

  or at least a further reduction of at least

  annular circles with the collar ends.

  To compensate for the longitudinal tolerances between the magnet elements, provision is made according to a preferred embodiment of the invention between

  at least one of the front faces of the segments of

  mantle and the annular covers that tighten them, an elastic spring element preferably in the form of a layer of elastically compressible synthetic material Depending on the length differences between

  magnet segments, the various elements of res-

  fate, elastics are compressed with a

  in all cases the magnet segments are fixed without the possibility of axial translation.

  According to an alternative embodiment of the invention

  the compensation of the longitudinal tolerances of the magnet segments is ensured in that at least one of the annular covers is subdivided into one

  number of cover segments corresponding to the

  of the magnet segments, and these segments of

  cle are made identically and enclose

each time a magnet segment.

  The present invention will be explained hereinafter

  in more detail with the help of an example of embodiment shown in the drawings Thus: Figure 1 is a longitudinal section

a permanent magnet rotor.

  Figure 2 is a section along the line

  II-II in Figure 1 of the permanent magnet rotor.

  Figures 3 and 4 each represent a longitudinal section of a permanent magnet rotor

  according to a second embodiment.

  FIG. 5 is a side view of the permanent magnet rotor without a rotor shaft, this view being taken in the direction of arrow V in FIG. 4

  before injection of synthetic material.

  Description of the embodiments

  The permanent magnet rotor represented in

  longitudinal section in Figure 1 consists of a

  support liner 10 and three magnet segments

  permanent 11 shell-shaped direct-applied

  on the support cylinder 10; as shown

  these segments are abutted in the direction

  The magnet segments 11 are

  in the radial direction.

  mant 11 are tight on the support cylinder 10 to

  with the aid of a fastening device 12 and are

  protected against centrifugal forces.

  Fastening device 12 consists of two annular covers 13, 14 of identical shape, each having a

  annular opening 15, 16 and a groove 17, 18 centrally

  the, coaxial with the corresponding annular opening

  , 16 The support cylinder 10 is shaped like a man

  chon 20 whose two ends each carry a collar 21, 22 whose wall thickness has been reduced and at the periphery of the sleeve 20 the wall thickness is greater than that of the collars 21, 22 of smaller thickness, forming body and thus defining an annular shoulder 23, 24 The distance

  axial axis of the two annular shoulders 23, 24 is also

  the or slightly less than the axial length of the

magnet segments 11.

  Each arcuate upper edge, of the end faces of the magnet segments 11, opposite the sleeve 20 is provided with a chamfer 25, 26 A cover edge 27, 28 corresponding to the chamfers 25, 26 is provided on each cover 13, 14 to overflow the corresponding chamfer 25, 26 when mounting

  the rotor is completed The outer diameter of the cover

  cle 13 is then equal to the outside diameter of the segments

magnet elements 11.

  For mounting the permanent magnet rotor,

  we cover the lids 13, 14 with their openings

  rings 15, 16 on the two collars 21, 22 of the

  sleeve 20 until their edges overflow-

  27, 28 the covers cover the chamfers

  , 26 of the magnet segments 11 Then, the two ends

  collar holes that penetrate the grooves 17, 18 of the covers 13, 14 are locked against the bottom of the

  17, 18 Covers 13, 14 shall apply

  if between the end faces of the magnet segments 11.

  The overflow edges 27, 28 are thus at the level of the chamfers 25, 26 radially above the magnet segments 11 and block them against the centrifugal forces generated by the rotation Due to the blocking, at least one collar ( in this case the

  collar 21) is fixed against the annular shoulder cor-

  respondent (in this case the annular shoulder 23) which also blocks the magnet segments 11

against any axial translation.

  In place of the blocking, by a suitable embodiment of the collars 21, 22, it could also be folded on the covers 13, 14 so that the folding edge formed by the end of the collar

  beyond the back of the throat 17, 18 and that the covers

  13, 14 are clamped in the same way against the magnet segments 11 and between the shoulders

annular 23.

  The sleeve 20 is fitted on the rotor shaft not shown here and is locked together

  in rotation on the shaft The magnet segments 11 serve

  13-14 generally have axial length tolerances. In order to avoid having to set tolerances that are too strict, it is

  the permanent magnet rotor shown in FIG.

  the front faces of the magnet segments 11 and the annular surfaces of the covers 13, 14, each

  one layer of synthetic material 29, 30

  elastically molded and which is preferably sprayed

  on the surfaces 11 of the annular covers (possibly

  also on the magnet segments)

  differences in length, the layers of syn-

  29, 30 are more or less compressed when clamping the collar ends 21, 22 of the sleeve 20, so that the magnet segments 11 are maintained

  in the axial direction, without any gap between

  13, 14 Basically, it would be sufficient to

  see only one such layer of synthetic material 29, 30 on one end face of the magnet segments 11. By having two layers, the thickness of each layer can be reduced, so that the chamfers 25, 26 of the

  magnet segments 11 are covered sufficiently

  by the overflow edges 27, 28 of the covers

keys 13, 14.

  In the case of the permanent magnet rotor of

  FIGS. 4 and 5, the compensation of the tolerances of

  axial distance between the magnet segments 11 are ab-

  sorbed because the cover 14 is subdivided into three distinct identical cover segments 141, 142, 143 (Fig. 5) Each cover segment 141, 142, 143 is associated with a magnet segment 11 and securely clamps the segment of magnet 11 with cover 13 Cover segments 141 143 are maintained

  on the one hand by the collar ends 21, 22

  of the sleeve 20 and, secondly, by a projection

  plastic material 31 of the magnet rotor

  manent which also connects the sleeve 20

  to a rotor shaft 32 The projection of synchronous material

  the thetic 31 fills the cavities and coaxial slots 17, 18 of the covers 13, 14 and the intervals

  which remain between the segments of cou-

circle 141 143.

Claims (7)

R E V E N D I C A T IO N S   1) Permanent magnet rotor for electric machines, in particular for constituting a rotor immersed in laundry pumps, fuel pumps or the like, comprising a support cylinder and several   shell-shaped permanent magnet segments   the applied on the support cylinder, these segments   abutting each other in the di-   circumference and being kept on the cylinder   support, jointly and severally rotated by   a fixing device, a characteristic rotor   characterized in that each arcuate upper edge opposite the support cylinder (10) on the end faces of the magnet segments (11) is provided with a chamfer (25, 26) and the fixing device (12). ) consists of two annular covers (13, 14) which are fitted on the end faces of the magnet segments (11) and protrude with an overflow edge (27, 28) adapted to each of the chamfers (25, 26) by   above them (25, 26) and in that the annular covers   (13, 14) are fixed axially locked   and radially on the support cylinder (10).   2) Rotor according to claim 1, characterized   rised in that the outer diameter of the lids   front rings (13, 14) is equal to the outer diameter   interior of the magnet segments (11).   3) Rotor according to claims 1 or 2,   characterized in that the support cylinder (10)   at each end of the cylinder, each time an annular shoulder (23, 24) provided at a distance from the front end and the axial distance   annular shoulders (23, 24) is equal to or slightly   lower than the axial length of the magnet segments (11) and that the annular covers   (13, 14) are clamped axially against the fronts   of the magnet segments (11), at least one cover   annular ring (13) being applied by a pressure   axial against an annular shoulder (23).   4) Rotor according to claim 3, characterized   in that the support cylinder (10) is in the form of a sleeve (20) having at each end a collar (21, 22) which is integral and of reduced wall thickness, and which projects axially beyond the magnet segments (11), the annular shoulders (23, 24) being formed by the junction of the sleeve (20) and the respective collar (21, 22) and that the openings   central rings (15, 16) of the annular covers   res (13, 14) are slightly larger than the outside diameter of the sleeve collars (21, 22)   and that the axial tightening of the annular covers   res (13, 14) is provided on the magnet segments (11)   by locking the collar ends against the necks   annular glasses (13, 14) or by at least one flap   part of the annular covers (13, 14) with the collar ends.   Rotor according to claim 4, characterized in that each annular cover (13, 14) has a groove (17, 18) coaxial with and adjacent to the annular opening (15, 16) and the axial length of the sleeve collars. (21, 22) is dimensioned so that these collars come into the grooves (17, 18) and in that the clamping and folding edge formed by the collar ends exceeds the base of each throat (17, 18).   6) Rotor according to one of claims 1 to   characterized in that to compensate for the length tolerances between the magnet segments (11) between at least one of the end faces of the magnet segments (11) and the annular surface of the annular cover   (13, 14) opposite this surface, there is provision for   spring elasticity (29, 30).   7. Rotor according to claim 6, characterized   in that the element having elasticity of the spring is constituted by a plastic layer (29, 30) elastically compressible.   8) Rotor according to one of claims 1 to   , characterized in that to compensate for the length tolerances between the different magnet segments   (11), at least one annular cover (14) is subdivided   referred to in a number of cover segments (141, 142, 143) corresponding to the number of magnet segments (11)