FR2722623A1 - 1 ELECTRIC MACHINE, IN PARTICULAR AN ALTERNATOR FOR A MOTOR VEHICLE - Google Patents

Abstract

Electric machine characterized in that the separate lamellae (11a) of the stator plate package (11), which are sandwiched between the bearing and centering surfaces (31) of the two housing halves (13, 14), are connected by at least two longitudinal connections symmetrical with respect to the clamping screws (15) and slightly spaced, these connections preferably being weld beads (32).

Description

"Electric machine including alternator for motor vehicle" State

  The invention relates to an electric machine, in particular an alternator for a motor vehicle, comprising a housing in two parts screwed by clamping screws for mounting the rotor and for enclosing the stator, the

  sheet package is made up of separate strips, connected in

  be they at the outer periphery by long links

  rigid longitudinal, in particular weld seams, and which comprises on at least several separate strips, at its outer edge zone, bearing and centering surfaces for receiving it in at least one of the

two housing halves.

  According to the utility model DE 91 07 542 we con-

  an alternator corresponding to this type is born, the pa-

  sheet metal is reinforced with weld seams

provided at the periphery.

  According to document DE 41 21 734 A1, a

  alternator of which only certain sheet metal lamellae,

  termini of the stator sheet package, are provided with deformations at the level of the clamping screws, at the outer periphery, and are received between the housing halves by bearing and centering surfaces. To fix the package of stator sheets, it is also known to provide instead of weld beads, on the periphery of the package of

  sheets, rivets in several places or even bos-

  wise matrixes in the form of grooves by which the different

lamellar rents are nested.

  The disadvantage of the known solutions is that the package of stator sheets, in particular at the level of the clamping between the two halves of the machine housing at the location of the clamping screws, is not rigid enough so that the excitations of oscillations can be

  transmit, through these clamping zones, to the entire housing.

  The electromagnetic oscillations thus emitted

  in the form of sound waves, represent an important part

  aunt of landing and ventilation noises in a range

  more or less the speed of rotation.

  The object of the present invention is to reduce the noise level of the machine by firmly clamping the stator between the housing halves of the machine, to reduce this noise level to a very large extent, and at the same time improve the mounting of the packet of stator sheets between

  the two housing halves at the clamping screws.

  Advantages of the invention The invention relates to an electric machine of the type defined above, characterized in that the lamellae separated from the package of stator sheets, which are clamped between the bearing and centering surfaces of the two halves

  housing, are connected by at least two long links

  tudinal symmetrical with respect to the clamping screws and slightly spaced, these connections being preferably

weld beads.

  The electric machine according to the invention offers the advantage that the package of stator sheets at the level of the

  support and centering surfaces of the two box halves

  tier, thanks to the longitudinal connections of the

  sheet metal, preferably consisting of two support cords

  hard, constituting a rigid set of blades, is tightened precisely and rigidly by a clamping screw mounted symmetrically between the halves of the housing. It

  There is also the advantage that the package of sheets of the sta-

  tor can no longer be resiliently compressed at the bearing and centering surfaces by the clamping screws of the two housing halves, but that it is mounted without clamping

  between the two housing halves. In addition, this rigidification

  cation of the stator sheet package by support cords

  lasts provided in pairs, allows adjusted stator tightening,

free of play, with radial centering.

  According to other advantageous characteristics of the invention: - the longitudinal connections preferably

  formed by weld beads at the level of the

  peripheral rection, correspond to an angular distribution

  irregular beam and, on either side of the clamping screws, they are offset by at least substantially a tooth division and parallel; - the weld beads are made in grooves provided in the outside diameter of the package

  sheets, each time above a tooth medium of different

  lamellar rents with internal teeth;

  - the weld beads are directed axially-

  ment, perpendicular to the front faces of the sheet pack;

  - the angular distribution of the support cords

  hard is not harmonic with respect to the polar division

of the machine.

  It is particularly advantageous if the over-

  bearing and centering faces of the two housing parts

  are segments of circle rings and lie each

  only when arranged symmetrically with respect to the clamping screws. For the stator radial blocking, there is another advantageous possibility in that, on at least one of the two housing halves, symmetrically with respect to the clamping screws, the rings of circle rings of the respective housing halves s '' apply in a pressed seat

  against the outer periphery of the sheet metal package of the

  tor. According to another characteristic, the half of the housing has, at the level of its ring segments of

  circle, centering surfaces offering resisting torque

  so much higher at radial forces than the peripheral zone

  than the middle of the housing half.

  According to other advantageous characteristics

his:

  - the radial resistive torque at the over-

  centering faces is at least twice that of the intermediate peripheral zones of the housing halves; - the wall of the housing halves which surrounds

  the stator plate package present in the peri-zones

  spheres between the centering surfaces, an air gap with respect to the outer periphery of the sheet pack; - the segments of circle rings presenting

  centering surfaces are connected by short branches

  dials to a bearing hub for radially stiffening the housing part; - The radial branches are provided each time in pairs and symmetrically on either side of the clamping screws; the housing halves have zones situated between the segments of circle rings provided with bearing and centering surfaces comprising air passages,

  - the wall of the housing halves, in the zo-

  nes peripherals situated between the bearing and centering surfaces, each time comprise another projecting part directed radially inwards, which encloses in a complementary manner the packet of stator sheets in

the radial and / or axial direction.

  Drawings Examples of embodiments of the invention are represented in the drawings and will be described below from

in more detail.

  Thus: - Figure 1 is a longitudinal section of a generator for motor vehicles comprising a stator enclosed according to the invention between two housing halves and corresponding to a first embodiment; - Figure 2 shows a detail of the stator clamping points; - Figure 3 shows, in cross section, a

  detail of the stator plate package with a pair of cor-

welding gifts;

  - Figure 4 shows another example of reali-

  sation of a clamping point in longitudinal section; - Figure 5 is a front view along IV-IV of Figure 4; - Figure 6 shows a top view of a third embodiment on the support and centering points of a half of the housing; - Figure 7 shows a longitudinal section with a stiffening rib, along V-V of Figure 6; - Figure 8 is a longitudinal section along

VI-VI of figure 6.

  Description of the exemplary embodiments

  The alternator (generator) for motor vehicle

  mobile, shown in longitudinal section in Figure 1, is

  essentially consists of a stator 10 consisting of a pa-

  quet of sheets 11, stacked; this package of sheets carrying a stator winding 12, three-phase, is tightened with screws 15 between the housing halves 13 and 14. The halves

  13 and 14 form on their front face pan-

  bearing rings receiving, on the drive side, a relatively large drive bearing 16 and, on the drive side

  brushes, a collector bearing 17 relatively lighter.

  A polar claw rotor 18 is provided in the stator; this rotor consists of two polar claw discs 19, 20 between which is clamped a flow guide part 21 carrying an excitation winding 22. The polar claw rotor 18 is hooped on the rotor axis 23; this

  axis is housed in the two bearings 16 and 17 and, at its ex-

  drive end, the axis carries a threaded part 24.-

  to fix a drive pulley. On either side of the pole claw rotor 18, the rotor axis 23 carries each

  times a ventilation disc 25, 26 to evacuate the heat

  their alternator loss.

  At the end of the axis 23, on the side of the brushes, there is a slip ring device for supplying the excitation winding 22; this device is connected

  by the carbon brushes of a brush holder 27, to a regu-

  reader 28 and to a rectifier assembly not shown. This

  rectifier assembly converts alternating current into

  continuous rant to supply the on-board network as well as a vehicle storage battery. The regulator 28 and the rectifier assembly are covered by a cover 29 in the form of a pot which is also fixed to the half of the housing 14 on the side of the brushes and receives the electrical terminals 30

of the alternator.

  Figure 2 shows a detail of an attachment point of the stator plate package 11 between the two housing halves 13, 14; the different lamellae

  clamps of the sheet pack are rigidly connected to the ni-

  calf of the bearing surfaces 31 of the housing halves 13, 14,

  each time by a weld bead 32 provided on both sides

  tees, symmetrically with respect to the clamping screw 15. The axial projecting part 33 of the housing halves 13 and 14 in the region of the clamping screws 15, causes the bearing surfaces 31, as shown in FIG. 1, radially adjacent centering surfaces 34 are segments of circle rings, symmetrical with respect to the

clamping screw 15.

  Figure 3 shows a detail of the sheet package 11 to be taken in combination with Figure 2; it appears that the weld beads 32 are each in pairs in the peripheral direction, on either side of the clamping screws 15, with a shift of a tooth division, for example 10; these cords are parallel. This figure also shows that the weld beads 32 are

  made in grooves 35 provided on the outside diameter

  laughing at the sheet pack 11, each time above a

  tooth segment of the different lamellae with internal teeth

  better. The weld beads 32 are directed, like the clamping screws 15, perpendicular to the end faces llb of the sheet metal package 11. As between the two beads

  weld 32 according to FIG. 3, there are three teeth 36 of the sta-

  tor of the stator winding 12, three-phase, it follows that the angular division of the weld beads 32 is not harmonic with the polar division T of the alternator,

which corresponds for example to 20.

  Figures 4 and 5 show a detail of a

  alternator corresponding to another example of realization

  tion, showing the clamping point of the stator; the same references will be used here to designate the same elements as in the first embodiment. Only the two

  housing halves 13 and 14 are slightly different.

  The important thing is to have a radial attachment of the stator 10 on the two housing halves 13, 14, each time by a

  seat pressed, so that the centering surfaces 34 pre-

  views symmetrically with respect to the clamping screws 15 on a circle ring segment 37 on the two housing halves 13, 14, are pressed with a slightly smaller diameter against the outer periphery of the sheet metal lamellae 11a, outside of the package sheets 11. For this, the two housing halves 13, 14 have, at the level of the circle segments 27 of the centering surfaces 34, a radial reinforcement 38 at the level of the clamping screws 15, in order to provide a higher resistant torque against the radial forces as the intermediate peripheral zones 39 of the halves

  housing 13, 14. So that on the one hand the peripheral zones

  39 located between the clamping points of the two me-

  casings 13, 14 can yield elastically in the

  radial direction, when pressing center surfaces

  trage 34 on the sheet pack 11, and on the other hand the air circulation allows the heat released in the sheet pack 11 to be removed, the wall of the housing halves 13, 14 enclosing the sheet pack 11 , in the peripheral zones 39 between the centering surfaces 34,

  an air gap 40 relative to the periphery of the pa-

  sheet quet 11. The reinforcement 38 at the clamping zones of the sheet pack 11 makes the resistant torque,

  radial, housing halves 13, 14 at the surfaces

  these of centering 34, is at least double that of the zones

intermediate devices 39.

  Figures 6 to 8 show, as another example of embodiment, one half of the bearing panel on the drive side of an alternator; this is the part

  upper half of case 13. Figure 6 shows

  feels a top view of the housing half seen from the side of the stator, as indicated by the

arrows VI-VI in Figure 7.

  Figure 7 is a cross section of the housing half 13 along the line VII-VII of Figure 6; Figure 8 is a corresponding cross section

  along line VIII-VIII of Figure 6. In this case also

  ment, at the clamping points, a bearing and centering surface 31, 34 has been produced each time on a ring ring of circle 37, symmetrically with respect to the clamping screws 15. The ring segments of circle 37 and the centering surfaces 34 are connected, as in the embodiment of Figures 1 and 2, for the

  radial reinforcement, by a branch 41 directed sensitive-

  radially, up to the bearing hub 42 of the housing part 13. The branches 41 are provided in pairs and symmetrically on either side of the clamping screws 15. Between the segments of circle rings 37 with the bearing and centering surfaces 31, 34, the housing part is provided, on its front face, with ventilation openings 43, 44 in the form of segments; the ventilation openings 43 radially on the outside arrive in the peripheral zone 39 situated radially on the outside, in order to reduce the resistance torque, radial,

  these areas (Figure 8). The air flow can penetrate through

  to the interior ventilation openings 44, for

  be driven by a radial fan 26 carried by the ro-

  machine tor towards stator winding head 10

  and from there go through the ventilation openings 43, ex-

  roof, as well as through the ventilation gap 40 above the sheet pack 11 to pass outside.

  In the case of electrical machines of power-

  sance important having long peripheral areas 39 between the clamping points, it may be interesting that the wall of the housing halves 13, 14 (as shown in Figure 6), present in the peripheral areas 39 located between the ring segments of circle 37 with the bearing and centering surfaces 31, 34, each time another radial projection 45 directed inwards, which ensures in

  in addition to a complementary radial and / or axial tightening of the fac-

  these fronts of the blades of the sheet metal package 11. In addition, for the shape given to the housing halves 13, 14 made of injected aluminum, of the electric machine, it may be advantageous to provide, at the threads 46 or passages 47 clamping screws 15 (as shown in

  Figures 4 and 5), each time an opening 48 in the seg-

  rings of circle rings 37 so that in each segment

  ring 37, the centering surface 34 is divided

  placed in two partial centering surfaces 34a, spaced from each other, symmetrically with respect to the screw

tightening 15.

  The invention is not limited to the embodiments shown. To have a precise tightening, without distortion, and as rigid as possible with respect to excitation by oscillations. Thus it can, for example, be advantageous to provide, instead of the weld beads 32 arranged in pairs in the direction

  axial, parallel cords in pairs but nevertheless

  axially wedged and, to reinforce the rigidity of the package

  of stator sheets 11, the weld beads 32, parallel

  the, in pairs, are offset from the cords of

  welding of neighboring pairs, shifting them in an op-

  asked. In addition, provision may also be made for the number of means for fixing the stator 10 in the axial direction and

  in the radial direction, in different angular ranges

  on the periphery of the stator for the halves of the box

  tier 13 and 14, for example by eight axial supports and four radial locking points. Thanks to the partially rigid ring segments 37 and the intermediate elastic peripheral zones 39, flexible and designed for the passage of cooling air, an advantage is obtained with respect to the known tightening on 360, support from

  rigid stator with respect to oscillations, compact, and

  tin, allowing to transmit in a directed way the ef-

  tightening forces and ensuring good contact for the evacuation of heat from the stator 10 to the housing halves 13, 14, while at the same time reducing the noise emitted. The partial axial clamping of the stator between the two housing halves 13, 14 also allows mounting without play without the need for hooped mounting, costly and sensitive to temperature. Different thermal expansions

  housing halves, for example aluminum, and sta-

  tor 10 for example made of sheet steel, lead, thanks to the zones of bearing panels, flexible elastic bands, between the clamping points of the stator, to a reduced deformation of the stator with respect to temperature variations. Finally, the manufacture of the pack of sheets 11 and of the housing halves 13 and 14 allows a less costly production, thanks to better compensation of the tolerances according to the invention,

than for known solutions.

  Instead of weld seams, you can also

  Lement rigidly connect the sheet metal lamellae constituting the package 11 in a different way, by longitudinal connections ensuring a partially rigid connection, for example rivets, combinations of bosses, stampings at the level of the different lamellae, by gluing

or by similar means.

RE V E N D I C A T I ONS

  1) Electric machine, including alternator

  for a motor vehicle comprising a housing in two parts

  ties screwed by clamping screws for mounting the

  tor and to enclose the stator whose sheet pack is

  formed of separate lamellae, interconnected at the peri

  external sphere by rigid longitudinal connections, in particular weld seams, and which comprises on at least several separate lamellae, at its external edge zone, bearing and centering surfaces to receive it in at least one of the two housing halves, machine characterized in that the separate lamellae (11a) of the stator plate package (11), which are clamped between

  the bearing and centering surfaces (31, 34) of the two parts

  case ties (13, 14), are connected by at least two longitudinal connections symmetrical with respect to the clamping screws (15) and slightly spaced, these connections being

  preferably weld beads (32).

  2) Electric machine according to claim 1,

  characterized in that the longitudinal connections of pre-

  ference constituted by weld beads (32) at the ni-

  calf of the peripheral direction, correspond to an irregular angular distribution and, on both sides of the clamping screws (15), they are offset by at least

  substantially a tooth and parallel division.

  3) Electric machine according to any one

  claims 1 or 2, characterized in that the cor-

  welding seals (32) are produced in grooves (35) provided in the outside diameter of the sheet pack (11), each time above a tooth medium of the different

  lamellae with internal teeth (lia).

  4) Electric machine according to one of the claims

  cations 1 to 3, characterized in that the supporting cords

  hard (32) are directed axially, perpendicular to

  front faces of the sheet pack (11).

  ) Electric machine according to one of the preceding claims, characterized in that the angular distribution of the weld beads (32) is not harmonic

  with respect to the polar division (T) of the machine.

  6) Electric machine according to claim 1, characterized in that the bearing and centering surfaces (31, 34) are produced in the form of ring segments

  circle (37) of the housing halves (13, 14) and are pre-

  seen each time symmetrically with respect to the clamping screws (15) and the weld beads (32) provided in pairs. 7) Electric machine according to claim 6, characterized in that the radial locking (34) of the stator (10) is provided on the segments of circle rings (37)

  which rest on a seat pressed against the periphery ex-

  of the stator sheet packages (11).

  8) Electric machine according to claim 7, characterized in that at least one half of the housing (13, 14) in the segments of circle rings (37) of the centering surfaces (34), has a higher resisting torque with respect to the radial forces that the peripheral zone (39)

  intermediate of the housing part (13, 14).

  9) Electric machine according to claim 8, characterized in that the radial resistive torque at the centering surfaces (34) is at least double that of the peripheral zones (39) intermediate the halves of

housing (13, 14).

  ) Electric machine according to one of the claims

  cations 7 to 9, characterized in that the wall of the halves

  housing (13, 14) which surrounds the package of stator sheets

  tor (11) present in the peripheral zones (39) between the centering surfaces (34), an air gap (40) by

  relative to the outer periphery of the sheet pack (11).

  11) Electric machine according to claim 8, characterized in that the segments of circle rings (37) having centering surfaces (34) are connected by radial branches (41) to a bearing hub (42)

  to radially stiffen the housing part (13, 14).

  12) Electric machine according to claim 11, characterized in that the radial branches (41) are provided each in pairs and symmetrically

  on either side of the clamping screws (15).

  13) Electric machine according to any one

  claims 10 or 11, characterized in that the

  housing halves (13, 14) have areas between the ring ring segments (37) provided with bearing and centering surfaces (31, 34) having passages

air (43, 44).

  14) Electric machine according to claim 10, characterized in that the wall of the housing halves (13, 14), in the peripheral zones (39) located between the bearing and centering surfaces (31, 34), comprise

  each time another projecting part (45) directed radially

  inwardly, which completely encloses

  keep the stator plate pack (11) silent in the direction

radial and / or axial.