WO2012025152A1

WO2012025152A1 - Rotor having salient poles and comprising wedging plates

Info

Publication number: WO2012025152A1
Application number: PCT/EP2010/062447
Authority: WO
Inventors: Patrick Orval; Nicolas Bruyere; Damien Birolleau
Original assignee: Renault S.A.S.
Priority date: 2010-08-26
Filing date: 2010-08-26
Publication date: 2012-03-01

Abstract

The invention relates to a rotor (10) having salient poles (18) for a rotating electric machine of a motor vehicle, comprising: a metal body (14) having a plurality of radially salient poles (18), each pole (18) having a main longitudinal axis (P); windings (34) wound about each pole (18); each pole (18) comprising a transverse shoulder surface (30); at least one wedging plate (38) transversally urging the winding (34) against an associated pole (18), a free outer end edge (40) of each wedging plate (38) being transversally retained by a longitudinal vertical retaining surface (42) of the shoulder surface (30), characterized in that the retaining surface (42) is formed at least partially in a vertical groove (44) formed in the shoulder surface (30).

Description

"Spiked rotor with wedging plates"

The invention relates to a protruding pole rotor of a rotating electrical machine which is intended to equip a motor vehicle.

The invention more particularly relates to a rotor with salient poles for a rotating electric machine of a motor vehicle which comprises:

- A metal body which is intended to be rotatably mounted about a central vertical axis and which is provided with a plurality of poles projecting radially from said central axis, each pole having a longitudinal main axis;

windings each of which is associated with a pole, each winding being made by winding at least one electrically conductive wire around said pole;

each pole comprising a shoulder transverse face which extends orthogonally to the polar longitudinal axis and makes it possible to retain the winding in the longitudinal direction;

at least one electrically insulating layer which is interposed longitudinally between the shoulder face and the winding;

at least one wedging plate which presses the winding transversely against the associated pole, an outer end free edge of each wedging plate being held transversely by a vertical longitudinal retaining face of the shoulder face.

In this type of rotor, the winding of each pole is subjected to a centrifugal force during the rapid rotation of the rotor. The winding sections which are arranged on the transverse faces of each pole are shifted transversely with respect to the longitudinal axis of the associated pole. Because of this shift, the centrifugal force exerted on these sections is inclined relative to the longitudinal axis of said pole. Said centrifugal force can be decomposed into a first longitudinal component and a second transverse component. The longitudinal component of the centrifugal force is entirely transmitted to the shoulder face of the pole. Thus, the winding is prevented from sliding longitudinally outwards along the pole.

On the other hand, the transverse component of the centrifugal force tends to spread transversely the winding of its pole. The winding is thus likely to be deformed locally, with a risk of rupture of the electric wire.

To prevent the winding from being damaged by this transverse component of the centrifugal force, it is known to mount a wedging plate on the pole. The centrifugal force exerted by the winding under the effect of the transverse component of the centrifugal force is entirely transmitted to this wedging plate. This wedging plate can be retained transversely by a lug which extends longitudinally inwards from the shoulder face of the pole.

In known manner, the lug has a thickness identical to or less than that of the insulating layer which is interposed between the winding and the shoulder face. This allows in particular to form the winding by winding the wire around the pole without the pin interferes with the winding operation. According to the state of the art, this lug is always salient with respect to the shoulder face.

The electrical insulators previously used with this pin principle make it possible to obtain an insulating layer of more than 1 mm thick. In order to improve the efficiency of the rotor, the use of insulating material has been proposed which makes it possible to obtain thinner insulating layers, for example of less than 0.5 mm. The thin insulating layer is for example made by a composite stack of very thin sheets. this allows in particular to produce coils with a larger volume of conductor wire with equal dimensions of poles.

However, the retaining lugs of the wedging plates are then projecting with respect to the insulating layer. This complicates the winding operation of the winding around the poles. The conductive wire is indeed likely to catch the lug during its winding near the shoulder face.

To solve this problem, the present invention proposes a rotor of the type described above, characterized in that the retaining face is formed at least partially in a vertical groove which is formed in the shoulder face next to the insulating layer and which is intended to receive the free end edge of the wedging plate.

According to other features of the invention:

- The retaining face is extended by a lug which extends radially projecting with respect to the shoulder face;

the lug has a longitudinal length which is at most equal to the thickness of the insulating layer;

the retaining face has a fillet formed in its free inner end edge.

Other characteristics and advantages will become apparent on reading the detailed description which follows for the understanding of which reference will be made to the appended drawings among which:

FIG. 1 is a cross-sectional perspective view showing a protruding pole rotor which is equipped with wedging plates which are mounted according to the teachings of the invention;

- Figure 2 is a cross-sectional view which shows schematically the centrifugal forces which are exerted locally on the winding; - Figure 3 is a detail view on a larger scale in cross section which shows the mounting means of the wedging plate of Figure 1 on the associated pole;

- Figure 4 is a view similar to that of Figure 3 in which only the mounting groove of the wedging plate has been shown.

For the rest of the description, elements having a similar structure, identical or similar will be designated by the same reference numbers,

For the remainder of the description, global orientations will be adopted without limitation:

- vertical which is oriented along the axis of rotation of the rotor and which is indicated by the arrow "V";

- Radials which are oriented orthogonally to the vertical direction from the inside to the outside starting from the central axis of rotation "A".

The vertical orientation is here used in a non-limiting way to simplify the understanding of the description and it is independent of gravity orientation.

Local orientations will also be adopted for each cluster:

longitudinal which is directed along the radial axis of said pole;

transverse which is orthogonal to the longitudinal direction and the vertical direction.

There is shown in Figure 1 a rotor 10 for a rotating electrical machine which is intended to equip a motor vehicle. This is for example an alternator or a starter or a motor.

Such a rotor 10 comprises a motor shaft 12 having a central vertical axis of rotation "A". A rotor body 14 is attached to the motor shaft 12. The body 14 is generally made of a metallic material. In the example shown in the figures, the body 14 is made by a vertical stack of horizontal metal sheets which are vertically clamped together by lag bolts (not shown). Such a body 14 is commonly called a "pack of sheets".

The body 14 has a central core 16 which has a passage opening of the motor shaft 12. Radial arms extend radially outwardly from the core 14. Each arm is intended to form a pole 18 projecting radially from the central axis of rotation "A". The poles 18 are generally arranged in pairs of poles 18 opposite to the central axis "A" of rotation.

For each pole 18 a local coordinate system is adopted in which the longitudinal orientation extends along the main radial axis of said pole 18, while the transverse orientation extends orthogonally to the vertical orientations of the central axis "A "and longitudinal of said pole 18.

The rotor 10 is here provided with four salient poles 18. Due to this number of poles 18, the core 16 has a section of square shape.

All the poles 18 having an identical structure, only a pole 18 will be described later, this description being applicable to all other poles 18, regardless of the number.

The pole 18 extends along an associated polar longitudinal axis "P" to a free outer end head 20. The pole 18 has a parallelepipedal shape. It is delimited vertically by two transverse end faces 22 and is delimited transversely by two vertical lateral faces 24.

The radially outer face 28 of the head 20 has a horizontal section in an arc. This allows the rotor 10 to rotate inside a stator (not shown) with reservation of an air gap between the outer face 28 of the head 20 and the stator. The head 20 has two flanges 26 which protrude transversely with respect to the lateral faces 24 of the pole 18. The lower face of each rim 26 thus forms a shoulder face 30 with respect to the associated lateral face 24 of the pole 18. The face shoulder 30 extends vertically and transversely so as to be turned towards the central axis "A" of rotation.

The shoulder face 30 delimits longitudinally outwardly a notch 32 side. The notch 32 is further delimited longitudinally inwards by the web 16, and transversely in one direction by the lateral face 24 of the pole 18. The notch 32 is thus open transversely in the direction opposite to the lateral face 24. The notch 32 is also open vertically at both ends of the rotor 10. Two notches 32 which are arranged are thus arranged transversely on either side of each pole 18.

A coil 34 is arranged around each pole 18. The coil 34 is formed by a winding of at least one electrically conductive wire around the longitudinal axis "P" of the pole 18. The wire is generally coated with an electrical insulator .

The coil 34 is arranged longitudinally between the shoulder face 30 and the core 16 of the rotor 10. Thus, a winding section 34 is received in each notch 32.

An insulating layer 36, which is made of an electrically insulating material, is interposed between each face 16, 24, 30 of the notch 32 and the coil 34. More particularly, an insulating layer 36 is interposed longitudinally between the coil 34 and the shoulder face 30.

As shown in FIG. 2, when the rotor 10 rotates at a high speed around its central axis "A" of rotation, a centrifugal force "F" is exerted locally on the winding section 34 which is housed in the notch 32 This centrifugal force "F" can be decomposed into a first component "FI" longitudinal and a second component "Ft" transverse.

The longitudinal component "FI" of the centrifugal force "F" is entirely transmitted to the shoulder face 30. In other words, the coil 34 is retained by the shoulder face 30 in the longitudinal direction against the longitudinal component "FI" of the centrifugal force "F".

On the other hand, the transverse component "Ft" of the centrifugal force "F" has the tendency to extend the winding section 34 transversely out of the notch 32.

For each notch 32, an associated wedging plate 38 is arranged to close transversely said notch 32. This wedging plate 38 thus makes it possible to press the winding section 34 transversely against the lateral face 24 of the pole 18.

The wedging plate 38 extends in a longitudinal vertical plane. The wedging plate 38 has a vertical length at most equal to the vertical length of the notch 32 and is delimited longitudinally outwards by a free end edge 40 and inwardly by a heel 41.

In the embodiment shown in the figures, the wedging plates 38 of two adjacent notches are formed integrally. Thus, each of the two wedging plates 38 forms a wing of a common angle. The rotor 10 having here four poles 18, the angle forms an angle of 90 °. The angle of the angle is formed by the common heel 41 of the two wedging plates 38.

All the notches 32 of the rotor 10 are closed by an identical setting plate 38. A single wedge plate 38 will therefore be described later.

The free outer end edge 40 of the wedging plate 38 is intended to be retained transversely by a face retaining face 42 vertical longitudinal shoulder face 30. This retaining face 42 allows a recovery of centrifugal forces.

Each angle formed of two wedging plate 38 is held in place by contact with each of the retaining faces 42 of the two notches 32 adjacent.

According to the teachings of the invention, the retaining face 42 is formed at least partially in a vertical groove 44 which is formed in the shoulder face 30.

The groove 44 is bounded transversely by the retaining face 42 and by an opposite face 43. The groove 44 is also delimited longitudinally outwards by a bottom 45, while it is open longitudinally inwards.

The groove 44 is arranged near the free transverse end of the shoulder face, next to the insulating layer 36. Thus, the groove 44 is not covered by the insulating layer 36.

However, the groove 44 is arranged so that the transverse thickness of material between the retaining face and the free transverse end of the head 20 is sufficient to withstand the centrifugal forces to resume without deforming or breaking.

The groove 44 thus accessible is intended to receive the free end edge 42 of the wedging plate 38. The groove 44 is delimited transversely opposite the pole 18 by said retaining face 42.

The free end edge 42 of the wedging plate 38 is thus fixed by a recess connection in the groove 44. Such an embedding connection makes it possible to reduce the thickness of the wedging plate 38 with respect to the solution of the state. of the technique which is described in the preamble of the description, and for equal centrifugal forces. This allows in particular to increase transversely the available volume for the winding of the pole. Advantageously, the retaining face 42 is extended vertically inwards by a lug 46 which extends vertically protruding from the shoulder face 30. This lug 46 has a length which is at most equal to the thickness of the insulating layer 36. This thus makes it possible to obtain a retaining face 42 of sufficient depth to take up the centrifugal forces "Ft", without preventing the winding operation of the winding wire 34 around the pole 18.

The lug 46 also makes it possible to reduce the depth of the groove 44. This makes it possible in particular to avoid the creation of rupture primers in the head 20 of the pole 18.

According to a not shown variant of the invention, the retaining face is not extended by a lug. The groove is then deep enough to allow the recovery of centrifugal forces.

Whatever the configuration adopted, the retaining face 42 advantageously has a fillet 48 formed in its free inner end edge. This fillet 48 makes it possible to avoid the concentration of stresses at the point of contact with the wedging plate 38.

During assembly of the rotor 10, the insulating layers 36 are inserted at the bottom of each notch 32. Then, a conductive wire is wound around each pole 18 so as to fill the notches 32.

The wedging plates 38 are then inserted vertically into each groove 44. For this purpose, the grooves 44 open vertically in at least one direction.

In this mounted position, the free end edges 40 are in transverse support against the retaining faces 42 of the associated grooves 44.

Advantageously, a mounting clearance is maintained between the free edge 40 of the wedging plate 38 and the bottom of the groove 44. A mounting set is also reserved transversely between the wedging plate 38 and the opposite face 43 of the groove 44. These two mounting sets also make it possible to prevent the wedging plate 38 from being mounted in a hyperstatic manner.

Claims

1. Rotor (10) with poles (18) projecting for a rotary electrical machine, in particular for a motor vehicle, which comprises:

a metal body (14) which is intended to be rotatably mounted about a central vertical axis (A) and which is provided with a plurality of poles (18) projecting radially from said central axis (A), each pole (18) having a longitudinal main axis (P);

- windings (34) each of which is associated with a pole (18), each coil (34) being formed by winding at least one electrically conductive wire around said pole (18);

- each pole (18) having a shoulder transverse face (30) which extends orthogonally to the polar longitudinal axis (P) and for retaining the coil (34) in the longitudinal direction;

at least one electrically insulating layer (36) which is interposed longitudinally between the shoulder face (30) and the coil (34);

at least one wedging plate (38) which presses the winding (34) transversely against the associated pole (18), an outer end free edge (40) of each wedging plate (38) being held transversely by one face vertical longitudinal retaining means (42) of the shoulder face (30);

characterized in that the retaining face (42) is formed at least partially in a vertical groove (44) which is formed in the shoulder face (30) adjacent to the insulating layer (36) and which is intended to receive the free end edge (40) of the wedging plate (38).

2. Rotor (10) according to the preceding claim, characterized in that the retaining face (42) is extended by a lug (46) which extends radially projecting from the shoulder face (30).

3. Rotor (10) according to the preceding claim, characterized in that the lug (46) has a longitudinal length which is at most equal to the thickness of the insulating layer (36).

4. Rotor (10) according to any one of the preceding claims, characterized in that the retaining face (42) has a fillet (48) formed in its free inner end edge.