FR2673493A1 - ALTERNATOR WITHOUT A COLLECTOR RING, PARTICULARLY A THREE-PHASE ALTERNATOR FOR MOTOR VEHICLES. - Google Patents

Abstract

The present invention relates to an alternator without a slip ring, and more particularly a three-phase alternator for motor vehicles, comprising in particular a stator assembly (15, 16) and an inductor composed of a fixed part (25) supporting an induction coil (26) and of 'a movable part consisting of two pole wheels (28,29) having at their periphery claws (31,32) to be connected by a ring (30) made of non-magnetic material. According to the invention, the claws (31,32) have on an inner face embedding means (33,34) of the ring (30).

Description

The present invention relates to an alternator without slip ring, and

especially a

  three-phase alternator for motor vehicles.

  Such an alternator comprises an inductor assembly in two parts, one fixed and the other movable in rotation, creating a flow variation with respect to a stator assembly consisting of a stack of stacked annular magnetic sheets, comprising over all its inner periphery, a plurality of notches allowing

to accommodate the stator winding.

  The fixed portion of the inductor assembly comprises an inductive coil, while the rotatable portion of said inductor assembly is constituted by a plurality of claws rotating inside the assembly.

  stator thus constituting a claw rotor.

  Such a rotor consists of two pole wheels, one being secured to the alternator shaft, the other being secured to the

  first by an element made of non-magnetic material.

  In a manner known per se, such an element is in the form of a circular ring whose section is rectangular This ring is fixed on the claws of the two pole wheels for example by screws or rivets. As a result, the points of contact between the ring and the pole wheels are punctual and this results in a certain fragility of the assembly thus formed, due in particular to the vibrations and to the speed of rotation more and more. motor generators are subject to high levels. In particular, the centrifugal force is such that it causes a deformation of the pole wheels at the level of the claws which is reflected at the level of

the ring.

  To improve the mechanical strength of such an assembly, a first method is to weld or glue the ring on the claws to increase

  the contact surfaces between the different elements.

  But such an arrangement, if it gives satisfaction on the functional level, prohibitively increases the cost of the whole of the alternator because of the

  additional operations it requires.

  A second method is to improve the inherent rigidity of the ring by increasing its section but the distance between the claws and the fixed part of the inductor being small, the section increase of the feasible ring is such that does not lead to

sufficient rigidity.

  The present invention solves these problems and proposes for this purpose an alternator without slip ring, and more particularly a three-phase alternator for motor vehicles, comprising in particular a stator assembly and an inductor composed of a fixed part supporting an inductor coil and a part mobile device consisting of two pole wheels having on their periphery claws to be connected by a ring of non-magnetic material, characterized in that the claws have on one side

  inner means of embedding the ring.

  Preferably, the embedding means consist of dovetail shaped notches formed on each of the pole wheels so as to form a dovetail when

  said pole wheels are nested.

  The ring has a section of complementary shape to the embedding means formed on the

polar wheels.

  Preferably, the section of the ring

  is at least partly in the shape of isosceles trapezium.

  Thus, not only is the section of the ring increased and thus its own resistance, but in addition a ring-shaped ring assembly is produced which has larger contact surfaces and therefore sufficient rigidity to withstand the deformations without damage.

to which this set is subject.

  The present invention will be better understood with the

  description which follows with reference to the attached drawings

  in which: Figure 1 is a sectional view of a set alteranteur according to the invention; Figure 2 is a sectional view on a larger scale of the pole wheels and a ring before assembly; FIG. 3 is a partial sectional view of a

  inductor assembly after assembly of the pole wheels.

  An alternator without a slip ring comprises two flanges 11 and 12 forming the casing of said alternator and provided with attachment lugs 13, 14. Between these two flanges 11, 12 is enclosed a stator assembly comprising a stator core 15 composed of a pack of sheets annular magnetic magnets comprising on all its inner periphery a plurality of notches, in which the winding is housed

stator 16.

  The stator assembly is held between the two flanges 11, 12 by screws 17. In the flanges 11, 12 are respectively arranged bearings 18, 19 intended for

receive a rotor shaft 20.

  On the side of the flange 11, are mounted integral in rotation with the rotor shaft 20, a drive pulley 21 and a cooling fan 22 On the flange 12 are fixed a bridge rectifier 23 and

regulator 24.

  The fixed part of the inductor 25 is made integral with the flange 11 and supports an inductor coil 26. The movable part of the inductor, integral in rotation with the rotor shaft 20, comprises on the one hand, a core 27, and on the other hand, a polar set with claws

  consisting of two pole wheels 28,29.

  The pole wheel 28 is carried directly by the rotor shaft 20, while the pole wheel 29 is connected to the pole wheel 28 by a circular ring 30.

made of non-magnetic material.

  Each pole wheel 28, 29 has at its periphery claws respectively 31, 32 which come to interlock alternately when the two wheels

Polar 28,29 are assembled.

  According to the invention, the claws 31, 32 have on their underside recessing means,

  respectively 33.34 of the ring 30.

  Preferably, as shown in particular in FIG. 2, these embedding means

  33,34 consist of notches in the form of half

  dovetail forming a complete dovetail

  when the pole wheels 28,29 are nested.

  The ring 30 of non-magnetic material has a cross section 35 of complementary shape to the embedding means 33,34 formed on the pole wheels 28,29. Preferably, the section 35

  of the ring 30 is an isosceles trapezium.

  The screws 17 enable the ring 30 to be secured to the pole wheels 28,29 Thus, the ring is really embedded in the pole wheels 28,29 and the assembly thus formed can withstand the deformations due to the centrifugal force resulting from the speeds high rotation rates to which

the alternator.

  Of course, the present invention is not limited to the embodiment described above and shown in the drawings but encompasses any variant

  or modification that the skilled person could make.

  In particular, the screws 17 can be replaced by rivets or pins without, for that reason, coming out of

of the present invention.

Claims (4)

  1) Alternator without slip ring, and more particularly a three-phase alternator for motor vehicles, comprising in particular a stator assembly (15, 16) and an inductor composed of a fixed part (25) supporting an inductor coil (26) and a part mobile device consisting of two pole wheels (28,29) having on their periphery claws (31,32) to be connected by a ring (30) of non-magnetic material, characterized in that the claws (31,32) have on one side interior of the embedding means (33,34) of the ring (30).   2) Alternator according to claim 1, characterized in that the embedding means (33,34) consist of notches, shaped dovetail half, formed on each of the pole wheels (28,29) of to form a dovetail when said   Polar wheels (28,29) are nested.   3) Alternator according to claim 2, characterized in that the ring (30) has a section (35) of complementary shape to the embedding means   (33,34) formed on the pole wheels (28,29).   4) Alternator according to claim 3, characterized in that the section (35) of the ring (30)   is at least partly in the shape of isosceles trapezium.