FR3131124A1 - Stator of a rotating electrical machine equipped with an insulator of an excitation winding - Google Patents

Abstract

The invention relates to a claw stator (11) for a rotating electric machine, in particular for a motor vehicle, having an axis (X) of revolution and comprising: - a first pole wheel (40) comprising a first half-yoke (41) and a plurality of first claws (42), - a second pole wheel (50) comprising a second half-yoke (51) and a plurality of second claws (52), - an excitation winding (60) and - an insulator (61) to physically isolate the excitation winding (60) from the first pole wheel (40) and from the second pole wheel (50). Characterized in that the excitation winding (60) and the insulator (61) are sandwiched between the first half-yoke (41) and the second half-yoke (51) on the one hand and the first claws ( 42) and the second claws (52) on the other hand. Figure of the abstract: figure 4

Description

Stator of a rotating electrical machine equipped with an insulator of an excitation winding

The present invention generally relates to rotating electrical machines.

More specifically, the invention relates to rotating machines of the alternator or alternator-starter type, used in motor vehicles.

The invention also finds a particularly advantageous application for the propulsion of low-power electric vehicles, in particular between 4kW and 5kW. The invention can thus advantageously be implemented in particular with low-power four-wheeled electric vehicles (“microcars”), two-wheeled vehicles of the motorcycle type, or heavy quadricycles.

More precisely still, the invention relates to rotating machines whose stator comprises claws, teeth and magnets, for example permanent magnets such as rare earth and/or ferrite magnets.

Almost all of the systems known for the traction of electric vehicles are based on alternating current motors, either synchronous with permanent magnets, or asynchronous.

Also known are propulsion systems for electric vehicles based on brushed direct current motors, and with separate excitation. Motor control essentially consists of a power adjustment on the armature (usual mode of speed control of a brushed DC motor) supplemented by a continuous flux variation on the inductor. Since such a control is smooth, the grip is often considered disconcerting, even unpleasant, by drivers who enjoy dynamic driving.

It has been known for many years so-called "claw-pole" rotors comprising an axis of axial symmetry, two pole wheels each comprising a flange bearing projections extended by axially oriented teeth directed towards the flange of the other pole wheel , a core between the flanges of the pole wheels, an insulator of an excitation winding mounted on the core, a coil, and at least one magnet mounted between two adjacent teeth belonging to one and the other of the pole wheels, wherein the insulator comprises a sleeve, mounted on the core, a front ring and a rear ring at each of the ends of the sleeve, at least one of these rings carrying a plurality of projecting petals intended to cooperate with the inclined internal periphery of a tooth, at least one petal among said plurality of petals having a generally trapezoidal contour, said petal projecting generally radially in the free state while being inclined axially in the direction of the second pole wheel and having a large base connecting to the periphery external of the crown, a small base configured to come into contact with said internal periphery of said tooth, at least two opposite sides connecting said large base and small base.

Such a rotating electrical machine rotor is for example disclosed in WO2011058254.

There is a need to have a stator for a rotating electrical machine, capable of being supplied with direct current, which is of simple construction and allows for simplified assembly and to facilitate its implementation.

The invention aims in particular to effectively remedy the aforementioned drawbacks by proposing a claw stator for a rotating electrical machine, in particular for a motor vehicle, having an axis of revolution and comprising:

- a first pole wheel comprising a first half-yoke and a plurality of first claws,

- a second pole wheel comprising a second half-yoke and a plurality of second claws,

- an excitation winding and

- an insulator to physically isolate the excitation winding from the first pole wheel and the second pole wheel.

The stator is remarkable in that the excitation winding and the insulator are sandwiched between the first half-yoke and the second half-yoke on the one hand and the first claws and the second claws on the other hand.

The invention makes it possible to isolate the excitation winding of the yokes simply with a small number of components.

According to one aspect of the invention, the stator has a circumferential alternation between the first claws and the second claws. Each first claw is framed circumferentially by two second claws.

According to one aspect of the invention, the first half-yoke and the second half-yoke form a yoke of the stator. The first half-yoke and the second half-yoke can be in axial contact, in particular along a cylindrical surface.

According to one aspect of the invention, the cylinder head has a radially outer surface. The radially outer surface of the yoke may be cylindrical.

According to one aspect of the invention, the first and second half-cylinder heads are identical. They are symmetrical along a plane transverse to the axis of revolution of the stator.

According to one aspect of the invention, the first claws and the second claws are radially inside the cylinder head.

According to one aspect of the invention, the first claws are all identical. The number of first claws can be between 4 and 12, in particular 8.

According to one aspect of the invention, the second claws are all identical. The number of second claws can be between 4 and 12, in particular 8.

According to one aspect of the invention, the first and second claws are identical.

According to one aspect of the invention, the first claws and the second claws overlap axially over at least 50% of their length, in particular 75% of their length.

According to one aspect of the invention, interclaw magnets are provided between the first claws and the second claws.

According to one aspect of the invention, the interclaw magnets can all be identical. The interclaw magnets are parallelepipedic.

According to one aspect of the invention, a single inter-claw magnet is provided between one of the first claws and one of the second claws.

According to one aspect of the invention, the inter-claw magnets can be fixed on the first claws or the second claws. As a variant, the inter-claw magnets are only held between the first and the second claws.

According to one aspect of the invention, the insulation comprises:

- an axial orientation sleeve on which the excitation coil is mounted and

- a first crown and a second crown, each folded down and placed at one of the ends of the sleeve.

According to one aspect of the invention, the insulation in the free state, that is to say not mounted in the stator, has folding crowns.

According to one aspect of the invention, the first crown is folded down by the first half-breech. The second crown is folded down by the second half-breech.

According to one aspect of the invention, the excitation winding is sandwiched between the first and the second crown on the one hand and the sleeve on the other hand.

According to one aspect of the invention, the first crown is sandwiched between the first half-yoke and the excitation coil.

According to one aspect of the invention, the second crown is sandwiched between the second half-yoke and the excitation coil.

According to one aspect of the invention, the first and the second crown insulate radially on the outside the excitation winding of the yoke.

According to one aspect of the invention, the sleeve insulates radially inside the excitation winding of the first and second claws.

According to one aspect of the invention, each of the first and second crowns cooperates with only one of the first and second pole wheels.

According to one aspect of the invention, each of the first and second rings has a free end and an end connecting with the axial sleeve. The connecting end may have material shrinkage. The narrowing can be local or extend over the entire circumference of the crown. The shrinkage can be obtained by pre-cutting. The narrowing allows the crowns to fold down so as to cover the sleeve.

According to one aspect of the invention, the first crown and the second crown define between them an axial distance of less than 5 mm, preferably less than 3 mm.

According to one aspect of the invention, the first and second crowns are flush.

According to one aspect of the invention, each of the first and second crowns is formed of a plurality of independent petals.

According to one aspect of the invention, the petals are rectangular. The petals can be between 8 and 50, in particular between 15 and 30, for example 25.

According to one aspect of the invention, the petals are spaced circumferentially from each other. An angular space can be provided between two petals of said petals which follow each other circumferentially. This angular space can be identical for all the petals. This angular space can increase when one moves axially away from the connecting end of the crown which defines the petals.

According to one aspect of the invention, the sleeve has an inner surface. The inner surface can be shaped to cooperate on the surface with the claws and, optionally, with the inter-claw magnets.

According to one aspect of the invention, the interior surface can be cylindrical. The sleeve may also have a prismatic inner surface. Such a surface makes it possible to match the flat shape of the claws and the inter-claw magnets and thus cooperate on the surface with them without leaving any empty space. Such a shape facilitates the positioning of the insulator relative to the first and second half-yokes.

According to one aspect of the invention, the excitation coil has two ends capable of being powered by a direct current power source. The ends of the excitation coil can emerge on the same axial side of the stator.

According to one aspect of the invention, the insulation has end guide tubes. The guide tubes can be axial. The guide tubes can protrude axially from one of the first and second half-yokes.

Each of the guide tubes may face one of the first claws and circumferentially between two second claws.

The invention also relates to a rotating electrical machine comprising a claw stator as defined previously.

According to one aspect of the invention, the rotating electrical machine comprises a rotor. The rotor may be surrounded by the stator. The rotor may be capable of rotating around an axis of rotation coinciding with the axis of revolution of the stator.

The rotor may include a polyphase winding. The rotor can be externally excited. The rotor may include magnets in addition to the winding.

According to one aspect of the invention, the rotor may be that presented in one of the four French applications 1901359, 1907210, 1907211 and 2007240 filed in the name of the Applicant.

According to one aspect of the invention, the electrical machine may comprise a casing. The housing may be composed of a first bearing and a second bearing. The stator can be fixed on each of the two bearings. As a variant, the stator can be fixed only on one of the first bearing and of the second bearing. The second bearing can comprise a transverse portion and an annular skirt. The stator can be fixed on the second bearing by force fitting via the cylinder head.

The invention also relates to a method for mounting a claw stator in which:

- the excitation coil is mounted on the insulator, the first crown and the second crown of which are not folded down,

- The insulator and the excitation coil are inserted in the first pole wheel so as to fold down the first crown,

- The second pole wheel is mounted on the insulation and the excitation coil so as to fold down the second crown.

Other characteristics, details and advantages of the invention will emerge more clearly on reading the detailed description given below, and several embodiments given by way of indication and not limitation with reference to the schematic drawings appended on the other hand. , on which ones :

is a representation of a rotating electrical machine before it is assembled and once assembled.

is a representation of a stator according to the invention,

represents a first assembly step of the stator of the ,

represents a second assembly step of the stator of the ,

In the example of the , there is shown a rotary electrical machine 10, in particular for a motor vehicle, having an axis X of rotation.

The rotating electrical machine 10 comprises a stator 11 surrounding an X-axis rotor 12, mounted on a shaft 13. The stator 11 of the machine 10 surrounds the rotor 12 with the presence of an air gap on an internal periphery of the stator and a outer periphery of the rotor. The rotor may include a polyphase winding. The rotor can be externally excited. The rotor may include magnets in addition to the winding.

The rotating electrical machine 10 may be intended to be coupled to a gearbox belonging to a motor vehicle traction chain. The rotating electrical machine 10 is then capable of operating in an alternator mode in particular to supply energy to the battery and to the on-board network of the vehicle, and in a motor mode, not only to ensure the starting of the heat engine of the vehicle, but also to participate in the traction of the vehicle alone or in combination with the combustion engine. The power of machine 10 may be between 4kW and 50kW. Alternatively, the electric machine 10 could be installed on an axle of the motor vehicle, in particular a rear axle.

In the example considered, the electric machine 10 advantageously has an operating voltage of less than 60 Volts, and preferably equal to 48 Volts. Typically, the torque provided by the electric machine is between 30N.m and 150N.m.

The rotating electric machine 10 is advantageously of the reversible type, that is to say it is capable of operating in a motor mode to apply a motor torque to the wheels from the electrical energy of the battery, and in a generator mode to recharge a battery from mechanical power taken from the wheels.

In the example considered, the electric machine 10 comprises a casing 20 composed of a first bearing 21 and a second bearing 22. The second bearing 22 comprises a transverse portion and an annular skirt 25 extending from an outer periphery of the first transverse.

The stator 11 is fixed on the second bearing 22 by force fitting. A yoke 27 of the stator is fitted onto the annular skirt 25 of the second bearing 22. The yoke 27 is fitted with shrink wrap. For this purpose, the second bearing 22 is heated to high temperature until the expansion of the material, then cooled so that the outer periphery of the stator 11 is held fixed against the annular skirt.

In the example considered, the casing 20 is provided centrally with a housing 30 receiving a bearing for the rotational mounting of the end of the rotor shaft.

With reference to Figures 2, 3 and 4, an example of a stator 11 according to the invention is described.

In the example considered, the stator comprises:

- a first pole wheel 40 comprising a first half-yoke 41 and a plurality of first claws 42,

- a second pole wheel 50 comprising a second half-yoke 51 and a plurality of second claws 52,

- a 60 excitation winding and

- an insulator 61 to physically isolate the excitation winding from the first pole wheel 40 and from the second pole wheel 50.

The excitation winding 60 and the insulator 61 are thus sandwiched between the first half-yoke 41 and the second half-yoke 51 on the one hand and the first claws 42 and the second claws 42 on the other hand.

In the example considered, the stator 11 has a circumferential alternation between the first claws 42 and the second claws 52. Each first claw is framed circumferentially by two second claws.

In the example considered, the first half-cylinder head 41 and the second half-cylinder head 42 form the cylinder head 27. The first half-cylinder head and the second half-cylinder head can be in axial contact, in particular along a cylindrical surface.

In the example considered, the yoke 27 has a cylindrical radially outer surface.

In the example considered, the first and second half-yokes 41, 51 are identical and they are symmetrical along a plane transverse to the X axis.

In the example considered, the first claws 42 are all identical and eight in number. The second claws 52 are all identical and eight in number. The first and second claws are identical.

In the example considered, the first claws and the second claws overlap axially over at least 50% of their length, in particular 75% of their length L. The length L is the maximum length of one of the first and second claws 42 , 52.

In the example considered, interclaw magnets 65 are provided between the first claws 42 and the second claws 52. Here, the magnets are all identical and parallelepipedic. A single interclaw magnet is provided between one of the first claws 42 and one of the second claws 52.

The interclaw magnets can be fixed or only held on the first claws 42 or the second claws 52.

In the example considered, the insulation 61 comprises:

- a sleeve 70 of axial orientation on which is mounted the excitation coil 60 and

- a first crown 71 and a second crown 72, each folded down and placed at one of the ends of the sleeve 70.

As can be seen at the , the insulator 61 in the free state, that is to say not mounted in the stator 11, has folding crowns.

In the example considered, the first ring is folded down 71 by the first half-yoke 41 and the second ring 72 is folded down by the second half-yoke 51. The excitation winding 60 is sandwiched between the first ring 71 and the second crown 72 on the one hand and the sleeve 70 on the other hand. Thus, the first crown 71 and the second crown 72 radially insulate the excitation winding 60 from the yoke 27 on the outside and the sleeve 70 radially insulate the excitation winding 61 from the first claws 71 and from the second claws 72.

In the example considered, each of the first and second rings 71, 72 cooperates with only one of the first and second pole wheels 40, 50.

In the example considered, each of the first and second crowns 71, 72 has a free end and a connecting end 74 with the sleeve. The connecting end may have material shrinkage. This narrowing can extend over the entire circumference of crowns 71, 72 and it can be obtained by pre-cutting. The narrowing allows the crowns to fold down so as to cover the sleeve.

In the example considered, the first crown 71 and the second crown 72 define between them an axial distance of less than 5 mm, preferably less than 3 mm. Preferably again, the first and second crowns 71, 72 are flush.

In the example considered, each of the first and second crowns 71, 72 is formed of a plurality of petals 75 independent. The petals are rectangular. The petals are for example 25.

In the example considered, the petals 75 are spaced circumferentially from each other and an identical angular space can be provided between two petals of said petals which follow each other circumferentially.

In the example considered, the sleeve has an inner surface 80 shaped to cooperate on the surface with the first claws 42 and the second claws 52 and with the inter-claw magnets 65. The inner surface 80 can be cylindrical or have a prismatic inner surface. Such a prismatic surface makes it possible to match the planar shape of the claws 71, 72 and of the inter-claw magnets 65 and thus cooperate on the surface with them without leaving any empty space. Such a shape facilitates the positioning of the insulator relative to the first and second half-yokes.

In the example considered, the excitation coil 60 has two ends 81 capable of being powered by a direct current power source, not shown. The ends 83 of the excitation coil can emerge from the same axial side of the stator 11. Openings are provided in the first bearing 21 for the passage of these ends towards the power source.

In the example considered, the insulator 61 has axial guide tubes 86 of the ends 83. The guide tubes can protrude axially from one of the first and second half-yokes 41, 51.

In the example considered, each of the guide tubes is facing one of the first claws and circumferentially between two second claws.

A method of mounting the stator 11 of the to 4 includes stages in which:

- the excitation coil 60 is mounted on the insulator 61 whose crowns 71, 72 are not folded down,

- The insulator 61 and the excitation coil 60 are inserted into the first pole wheel 40 so as to fold down the first crown 71,
- The second pole wheel 50 is mounted on the insulator 61 and the excitation coil 60 so as to fold down the second crown 72

Claims (10)

Stator (11) with claws for a rotating electrical machine, in particular for a motor vehicle, having an axis (X) of revolution and comprising:
- a first pole wheel (40) comprising a first half-yoke (41) and a plurality of first claws (42),
- a second pole wheel (50) comprising a second half-yoke (51) and a plurality of second claws (52),
- an excitation winding (60) and
- an insulator (61) to physically isolate the excitation winding from the first pole wheel (40) and from the second pole wheel (50).
Characterized in that the excitation winding (60) and the insulator (61) are sandwiched between the first half-yoke (41) and the second half-yoke (51) on the one hand and the first claws ( 42) and the second claws (52) on the other hand. Claw stator (11) according to any one of the preceding claims, characterized in that inter-claw magnets (65) are provided between the first claws and the second claws. Claw stator according to the preceding claim, in which the insulator comprises:
- a sleeve (70) of axial orientation on which is mounted the excitation coil and
- a first crown (71) and a second crown (72), each folding and each disposed at one of the ends of the sleeve (70). Claw stator (11) according to the preceding claim, characterized in that the first crown (71) is sandwiched between the first half-yoke (41) and the excitation coil (60) and in that the second crown (72) is sandwiched between the second half-yoke (51) and the excitation coil (60). Claw stator (11) according to either of Claims 3 and 4, characterized in that the first crown (71) and the second crown (72) define between them an axial distance of less than 5 mm, preferably less than 3 mm. Claw stator (11) according to any one of Claims 3 to 5, characterized in that each of the first and second crowns (71, 72) is formed of a plurality of independent petals (75). Claw stator (11) according to any one of Claims 3 to 5, characterized in that the sleeve (70) has a cylindrical or prismatic inner surface (80). Claw stator (11) according to any one of the preceding claims, characterized in that the excitation coil (60) has two ends (83) capable of being supplied by a direct current supply source and in that the insulator has guide tubes (86) from the ends of the excitation coil. Rotating electrical machine (10) comprising a claw stator (11) according to any one of the preceding claims. A method of mounting a claw stator (11) according to Claim 2 or any one of Claims 3 to 7 dependent on Claim 2, in which:
- the excitation coil (60) is mounted on the insulator (61) of which the first crown (71) and the second crown (72) are not folded down,
- The insulator (60) and the excitation coil (60) are inserted into the first pole wheel (40) so as to fold down the first crown (71),
- The second pole wheel (50) is mounted on the insulator (61) and the excitation coil (60) so as to fold down the second crown (72).