BRPI0818263A2 - rotary electric machine and manufacturing process of a rotary electric machine - Google Patents

Description

(54) Title: ELECTRIC ROTATING MACHINE AND MANUFACTURING PROCESS OF AN ELECTRIC ROTATING MACHINE (51) Int. Cl .: H02K 3/48; H02K 15/00 (30) Unionist Priority: 11/13/2007 FR 0758998 (73) Holder (s): VALEO EQUIPEMENTS ELECTRIQUES MOTEUR (72) Inventor (s): ERIC TORA; JACQUES

VEROT; ERIC VERNAY (74) Attorney (s): MONSEN LEONARDOS & CIA (86) International Request: PCT FR2008052036 of 11/13/2008 (87) International Publication: WO

2009/068814 of 06/04/2009

“ELECTRIC ROTATING MACHINE AND MANUFACTURING PROCESS OF AN ELECTRIC ROTATING MACHINE”

The invention relates to a rotating electric machine, for example a starter motor vehicle, and to a process for manufacturing such a machine.

Patent applications FR 2,708,398, FR 2,721,769 and FR 2,875,068 describe different manufacturing processes for starter motor rotors for automotive vehicles. These known processes comprise a step of crushing the threads in rotor notches and / or a step of setting the rotor to form teeth.

All of these processes comprise, on the other hand, a step of impregnating the conductive threads with a varnish to ensure the immobilization of the threads in the notches thus creating an adhesion between those threads.

Impregnating the rotor with a varnish can prove problematic, notably due to the necessary industrial facilities, and the relatively long time of operation.

In addition, the varnish may have the drawback of reducing the heat exchange capabilities of the rotor.

There is a need to correct the inconveniences mentioned.

The present invention thus has as its object a rotating electric machine, notably a starter motor vehicle, which comprises:

- a stator,

- a rotor arranged so that it can rotate in the stator around a longitudinal axis,

- at least one coil comprising conducting segments,

- a plurality of notches formed in one of them the stator or the rotor which extend substantially according to the longitudinal axis, which each have a bottom, at least one of the notches receiving at least one conducting segment of the coil, characterized by the fact that said at least one conductive segment is supported against the bottom of the notch and has a crushing deformation that is sufficient to ensure its retention in the notch during normal operation of the rotating electric machine.

Thanks to the invention, during the life of the electric machine, the conductive segments can be retained in the corresponding notches without an additional means other than crushing them.

In particular, the electrical machine can advantageously be devoid of varnish placed in contact with the conductive segments in the notches, after mounting the rotor in the stator.

The invention thus makes it possible to avoid operations of impregnating the rotor with a varnish, which simplifies the manufacture of the rotor, without altering the thermal exchange capacities of the latter.

In particular, the energy useful for the manufacture of the rotor can be reduced, which makes it possible to reduce the CO ₂ mark of the rotor according to a concern for respect for the environment.

In an exemplary embodiment of the invention, at least one of the notches receives at least two conductive segments, notably aligned substantially according to a radius of the rotor.

For example, each notch can receive four conductive segments aligned according to a rotor radius.

In a variant, at least two conductive segments in the same notch can be substantially aligned according to a circumference of the rotor.

Preferably, each conducting segment has an elongated cross section according to a circumference of the rotor, this shape being given when the conducting segment is crushed.

In an exemplary embodiment of the invention, each conductive segment may have, before crushing deformation, a circular, even oval, cross section. This circular cross section is found in the coil balls.

The coil is for example formed by one or more threads.

As a variant, each conducting segment may have, before crushing, a polygonal cross section, notably rectangular or square.

The ratio between the thickness of that segment after crushing and that before crushing is called the “crush rate” of a conducting segment.

A conductor segment's “shape relationship” is the relationship between the thickness of that conductive segment and its width.

At least one of the conductive segments, notably all the conductive segments in the notches, has (m) advantageously a crushing rate in the range [0.6; 1], notably in the range [0.7; 0.9], notably still in the range [0.75; 0.85],

Preferably, at least one of the conductive segments, notably all of the conductive segments in the notches, has (m) a relation between the range [0.66; 1], notably in the range [0.68; 0.84], notably still in the range [0.7; 0.75].

In particular, the shape ratio can be substantially equal to 0.71.

In an exemplary embodiment of the invention, the notches may each comprise a longitudinal opening opposite the bottom, and at least one of the notches may comprise a free space that extends between the conductive segment closest to the opening of the notch and the opening itself , this free space being made when the conductor segment (s) is crushed in the notch.

Preferably, the depth of the free space is in the range [0.1 mm; 2 mm].

If desired, the depth of the slot free space is substantially zero.

Advantageously, at least one of the notches, notably all the notches, has (m) a filling rate, defined as the relationship between the section occupied by the conducting segments in a notch and the section of the empty notch, included in the interval [60%; 98%], notably in the range [70%; 95%], notably still in the range [75%; 92%].

In an exemplary embodiment of the invention, the notches can be formed in a body, notably a rotor body, and the body can comprise at least one tooth, which protrudes from one of the notches, that tooth allowing the conductive segments to be kept in place inside the notch.

In particular, the tooth may extend at least partially into the free space of the notch.

The rotor body may comprise a longitudinal groove that extends above the tooth, that groove being initially provided to facilitate deformation of the rotor body with a view to forming that tooth.

The bottom of each notch may have a concave concave shape in cross-section directed towards the interior of the notch, this form being substantially complementary to that of the conducting segments.

In an exemplary embodiment of the invention, at least one of the notches can comprise two substantially flat longitudinal facing walls.

In a variant, at least one of the notches may comprise two longitudinal walls, facing each other, these walls having hollow and raised forms that allow to notably improve the retention of the conductive segments within the notch.

The electrical machine may comprise at least one insulating sheet sandwiched between at least one conductive segment and a wall of the notch.

The invention also has as its object a manufacturing process for a rotating electric machine as defined above, the process comprising the following steps:

a / insert at least one conductive segment in each notch, and b / apply a sufficient crushing effort over that conductive segment to give it a deformation that allows its retention in the notch during normal operation of the rotating electric machine.

The process may also comprise the following stage:

w / locally fix the rotor body in order to form one or more teeth on it that protrude from the notch.

If so, steps b / and c / can be concurrent.

As a variant, step b / precedes step c /.

The crushing effort can be variable over a length of at least one of the conductive segments.

Preferably, the crushing effort is greater in a central area of the conductive segment than in peripheral areas of the conductive segment.

Thus, the central area of the conductive segment in the notch may present a greater deformation than that of the peripheral areas of the conductive segment.

The invention can be better understood by reading the detailed description that you are going to follow, of examples of non-limiting execution of the invention, and by examining the attached drawing, in which:

- figure 1 represents, schematically and partially, an electric rotating machine according to an embodiment of the invention,

- figure 2 represents, schematically and partially, in an isolated way, the rotor of the machine of figure 1,

- figure 3 represents, schematically and partially, in cross section according to III-III, the rotor of figure 2,

- figure 4 represents, schematically and partially, in cross section, a conductive segment of the machine in figure 1, before crushing,

- figure 5 represents, schematically and partially, in cross section according to V-V, the rotor of figure 2,

- figure 6 represents, schematically and partially, in cross-section, a rotor of an electric machine according to another example of implementation of the invention,

- figure 7 represents, schematically and partially, in cross-section, a rotor of an electric machine according to yet another example of implementation of the invention, and

figures 8 and 9 schematically and partially represent crushing punches according to two examples of the invention.

In figure 1, a rotating electric machine that forms a motor starter 1 for an automotive vehicle was represented.

This starter 1 comprises, on the one hand, a rotor 2, also called armature, which can rotate around a longitudinal axis X, and on the other hand, a stator 3, also called inductor, around the rotor 2.

Starter 1 has an electrical power of 1 kW.

The stator 3 comprises a yoke 4 which carries a plurality of permanent magnets 5.

The rotor 2 comprises a rotor body 7 arranged perpendicularly to the magnets 5 of the stator 3, and a coil 8 wound around notches of the rotor body 7.

Starter 1 can be a six-pole magnet type for example.

As a variant, the stator can comprise a coil in place of the magnets.

The coil 8 comprises a plurality of conducting wires that form, on one side and the other of the rotor body 7, a front ball 9 and a rear ball 10.

The rotor 2 is provided, at the rear, with a collector 12 comprising a plurality of contact parts electrically connected to the coil 8.

A group of brushes 13 and 14 is provided for the electrical supply of the coil 8, one of the brushes 13 being connected to the ground of the device 1 and another of the brushes 14 being connected to an electrical well 15 of a contactor 17 via a wire 16. For example, there are four brushes.

Brushes 13 and 14 rub against the collector 12 when the rotor 2 is rotating.

The starter motor 1 further comprises a launcher assembly 19 slidably mounted on a drive shaft 18 and which can be driven in rotation around the X axis by the rotor 2.

A speed reduction assembly 20 is interposed between the rotor 2 and the drive shaft 18, in a manner known per se.

The launcher assembly 19 comprises a drive element formed by a pulley 21 and intended to be inserted into a drive member of the combustion engine, not shown. This drive member is, for example, a belt.

The pulley 21 can be replaced by a gear element, notably a sprocket, to drive the combustion engine.

The launcher assembly 19 further comprises a freewheel 22 and a pulley washer 23 that define a flute 24 between themselves to receive the end 25 of a fork 27.

This fork 27 is driven by the contactor 17 to move the launcher assembly 19 in relation to the drive shaft 18, according to the X axis, in a manner known per se.

The contactor 17 comprises, in addition to the boom 15 connected to the brush 14, a boom 29 connected via an electrical connection element, notably a wire 30, to a vehicle electrical supply, notably a battery, not shown.

Rotor 2 will now be described in more detail in reference to Figures 2 to 5.

As shown in figure 3, the rotor body 7 comprises a plurality of notches 40 that extend according to the X axis, each notch 40 having a bottom 41, two substantially flat longitudinal walls 42 and 43 and an opposite longitudinal opening 44 bottom 41.

The bottom 41 of each notch 40 has a concave concave shape in cross section directed into the notch 40.

Each notch 40 on the other hand comprises at least one insulating sheet 34 interspersed between the conductive segments 11 inserted in the notch 40 and the walls 42 and 43.

This insulating sheet 34 extends, on the one hand, along the walls 42 and 43 and at the bottom 41, and, on the other hand, on an outer periphery 28 of the rotor body 7.

In the example described, each notch 40 receives four conductive segments 11 of the coil 8 aligned substantially according to a radius of the rotor 2.

The conductive segments 11 are formed by portions of threads of the coil 8, which threads comprise a conductive core 31 and an insulating sheath 32, for example made of enamel.

The conductive segments 11 are placed in place within the corresponding notches 40 in the following manner.

These conductive segments 11, initially formed by portions of wires of circular cross section, as illustrated in figure 4, are placed in the corresponding notches 40.

And then with the aid of a tool 50 provided with a central punch 51, the conducting segments 11 are crushed in each of the notches 40, as can be seen in figure 5.

The central punch 51 is arranged to occupy the entire length of the notch 40 when it is introduced in the latter.

The crushing effort is chosen so that the deformation suffered by the conductive segments 11 within the corresponding notch 40 is sufficient to keep them in place during the normal operation of the electric machine.

On the other hand, tool 50 comprises lateral punches 52 in order to generate, when crushing the conducting segments 11, a deformation of the rotor body 7 with a view to locally creating teeth 46, in each notch 40, which come to rest on the conductor segment 11 more radially outer.

In the example described, the side punches 52 are connected to the central punch 51.

In a variant, the side punches 52 can be arranged to be able to slide in relation to the central punch 51.

These teeth 46 ensure the reinforced retention of the conductive segments 11 within the corresponding notch 40.

In order to facilitate the formation of teeth 46 when crimping with the aid of side punches 52, the rotor body 7 is initially provided with longitudinal grooves 47 which create zones of preferential deformation.

These grooves 47 are present after crimping and located immediately above teeth 47.

As shown in figures 2 and 3, the rotor 2 is devoid of varnish placed in contact with the conductive segments 11 in the notches 40, after mounting the rotor 2 in the stator 3.

The process does not require impregnating the conductive segments with a varnish.

As illustrated in figures 3 and 5, each conductor segment 11 presents, after crushing, an elongated cross section according to a circumference of the rotor 2.

It is noted “e and the thickness of a conductive segment 11 measured according to a Y radial axis and“ 1 ”its width measured according to a Z axis perpendicular to the Y axis, the Y and Z axes being contained in a plane perpendicular to the X axis .

The shape relationship (e / 1) is defined as the relationship between the thickness and the width 1 of a conducting segment 11.

In the example described, the conductive segments 11 inserted in the slots 40 have a substantially equal ratio of 0.7.

As illustrated in figure 4, each conductive segment 11 presents, before crushing, a circular section that defines an initial thickness that is noted “e ₀ ”.

The relationship between the thickness of a conductive segment 11, after its crushing, and its initial thickness and ₀ , defines a crushing rate (and / and ₀ ) of that conductive segment 11.

In the example described, the conductive segments 11 inserted in the notches 40 have a crush rate within a range [0.75; 0.9].

Each notch 40 comprises a free space 45 that extends between the conductive segment 11 closest to the opening of the notch 44 and the opening 44 itself, the free space 45 having a depth p measured according to the Y axis.

The depth p is chosen substantially equal to 1.6 mm.

Each notch 40 has a filling rate, defined as the relationship between the section occupied by the conductive segments 11 in a notch 40 and the empty notch 40 section, comprised in an interval [65%; 80%].

In the implementation example of the invention, the rotor of the electric machine has the following characteristics:

- initial thickness of a conductive segment and ₀ = 2 mm;

- thickness of a conductive segment after crushing e = 1.57 mm;

- width of a conductive segment after crushing 1 =

2.26 mm;

- shape ratio = 0.69;

- crushing rate - 0.78;

- depth of the slot free space = 1.57 mm;

- fill rate = 76%.

Naturally, the invention is not limited to the implementation example just described.

For example, in a variant of the rotor according to the invention illustrated in figure 6, each free space 45 a of the rotor 2a has a very small depth, substantially equal to 0.4 mm, and the filling rate is comprised in an interval [80%; 98%].

For example, figure 7 illustrates a variant of the rotor according to the invention, in which that rotor 2b comprises notches 40b comprising two facing longitudinal walls 42b and 43b, these walls 42b and 43b having hollow shapes 48b and in reliefs 49b.

These hollow shapes 48b and in reliefs 49b allow to receive the conductive segments 11 with reinforced retention of these conductive segments 11 within the notches 40b.

In the example described with reference to figure 5, the crushing punch 51 of the conductive segments 11 can have a straight leading edge at least over the length of the notch 40.

In a variant, as can be seen in figure 8, the punch 51 may comprise a straight edge 511 extended on one side and the other by indentations 512.

These indentations 512 have a curved concave shape directed towards the conductive segment 11.

When the punch 51 crushes the conductive segments 11, the straight edge 511 is applied over a central area of the conductive segment 11 and causes the central area to be crushed.

At the same time, indentations 512 are applied progressively over the peripheral areas of the conductive segment 11 and crush them with less effort.

A variable crushing effort is thus applied by the punch 51.

In the exemplary embodiment of the invention illustrated in Figure 9, the punch 51 comprises a central punch element 513 and, on one side and the other side of the latter, two peripheral punch elements 514.

These punch elements 513 and 514 each have a straight edge and are independent of each other.

When punch 51 smashes one of the conductive segments 11, the leading edge of the central punching element 513 is applied over the central area of the conductive segment 11 in the notch 40 after a path c ₂ .

The peripheral puncture elements 514 are moved in a path C3 less than the path c ₂ of the central puncture element 513 so that the conductive segment 11 is more crushed in a central zone than in axially peripheral zones.

Claims (17)

1. Electric rotating machine (1), notably a starter motor vehicle, comprising: - a stator (3), - a rotor (2, 2a) arranged so that it can rotate in the stator (3) around a longitudinal axis (X), - at least one coil (8) comprising conducting segments (11), - a plurality of notches (40) formed in one of them the stator (3) or the rotor (2, 2a) which extend substantially according to the longitudinal axis (X), which each have a bottom (41), at least one of the notches (40) receiving at least one conducting segment of the coil (11), characterized by the fact that said at least one conducting segment (11) is supported against the bottom of the notch (41) and presents a deformation by crushing which is sufficient to ensure its retention in the notch (40) during normal operation of the rotating electric machine (1). 2. Machine (1) according to the preceding claim, characterized by the fact that it is devoid of varnish placed in contact with the conductive segments (11) in the notches (40), after mounting the rotor (2, 2a) in the stator (3). Machine (1) according to either of claims 1 or 2, characterized in that at least one of the notches (40) receives at least two conductive segments (11), notably aligned substantially according to a radius of the rotor ( 2, 2a). Machine (1) according to any one of the preceding claims, characterized in that each conducting segment (11) has an elongated cross section according to a rotor circumference (2, 2a). Machine (1) according to any one of the preceding claims, characterized by the fact that at least one of the conductive segments (11), notably all the conductive segments (11) in the notches (40), presents (m) advantageously a crushing rate in the range [0.6; 1], notably in the range [0.7; 0.9], notably still in the range [0.75; 0.85]. Machine (1) according to any one of the preceding claims, characterized by the fact that at least one of the conductive segments (11), notably all the conductive segments (11) in the notches (40), has (m) a relationship comprehensively in the interval [0.66; 1], notably in the range [0.68; 0.84], notably still in the range [0.7; 0.75], Machine (1) according to any one of the preceding claims, the notches (40) each comprising a longitudinal opening (44) opposite the bottom (41), characterized by the fact that at least one of the notches (40) it comprises a free space (45, 45a, 45b) that extends between the conductive segment (11) closest to the opening of the notch (44) and the opening itself (44). 8. Machine (1) according to any one of the preceding claims, characterized by the fact that at least one of the notches (40), notably all of the notches (40), has (m) a filling rate, included in the interval [ 60%; 98%], notably in the range [70%; 95%], notably still in the range [75%; 92%]. Machine (1) according to one of claims 7 and 8, characterized in that the depth of the free space (45, 45a, 45b) is substantially zero. 10. Machine (1) according to any one of the preceding claims, characterized by the fact that the notches (40) are formed in a body (7), notably a rotor body (2, 2a), and by the fact that the body (14) comprises at least one tooth (46) that protrudes from one of the notches (40). Machine (1) according to any one of the preceding claims, characterized in that the body (7) comprises a longitudinal groove (47) that extends above the tooth (46). Machine (1) according to any one of the preceding claims, characterized in that at least one of the notches (40) comprises two substantially flat longitudinal facing walls (42, 43). Machine (1) according to any one of claims 1 to 11, characterized in that at least one of the notches (40) comprises two facing longitudinal walls (42b, 43b), these walls having hollow shapes (48b) and in relief (49b). 14. Manufacturing process for a rotating electric machine (1) according to claim 1, characterized by the fact that it comprises the following steps: a / insert at least one conductive segment (11) in each notch (40), and b / apply a sufficient crushing effort on that conductive segment (11) to give it a deformation that allows its retention in the notch (40) on occasion normal operation of the rotating electrical machine (1). 15. Process according to the preceding claim, characterized by the fact that it also comprises the following stage: w / locally fix the rotor body (7) in order to form on this body (7) one or more teeth (46) that protrude from the notch (40), notably with the aid of a punch (52). 16. Process according to the preceding claims, characterized by the fact that steps b / and c / are concomitant. 17. Process according to any one of the claims 14 to 16, characterized by the fact that the crushing force is variable 5 in the length of the conductive segment (11) in the notch (40). 1/5 X 2/5 3/5 4/5 5/5