FR3093387A1 - Connection device for stator - Google Patents

Abstract

Connection device for a stator Connection device (1) for a stator, comprising: Peripheral metal elements (20) each comprising at least one tab (22) for connection to at least one conductor (E) of the stator winding, this tab having a groove (26) open radially outwards to receive the conductor, this groove (26) being delimited at least partially by a flanged edge (120), preferably oriented radially, at least some of these peripheral metal elements (20) comprising furthermore at least one tab (23) for connection to a power supply bus of the stator, at least part of the metal elements (20) comprising curvilinear portions (21) connecting the connection tabs between them, an insulating support (10 ) holding the metal elements, preferably comprising housing for receiving the metal elements. Figure for the abstract: Fig. 20

Description

Connection device for stator

The present invention relates to synchronous or asynchronous alternating current machines, and in particular traction or propulsion machines for electric ( Battery Electric Vehicle ) and/or hybrid ( Hybrid Electric Vehicle – Plug-in Hybrid Electric Vehicle ) motor vehicles, such as whether individual cars, vans, trucks or buses. The invention also applies to rotating electrical machines for industrial applications and/or energy production, in particular naval or wind turbines.

The invention relates more particularly to the connection devices used to connect the windings of a stator to a supply bus thereof.

It is known to use connection devices to facilitate the connection of the windings of an electric machine stator to a power supply bus.

Such a connection device is known from application US 2011/0175471, and comprises three metal elements having connection lugs to the conductors of the stator as well as to the supply bus, and a plastic support, molded onto these elements. The conductor connection tabs are mostly open in the circumferential direction.

The fact of overmolding the support gives fewer degrees of freedom to the mounting of the device on the stator.

In addition, the overmolding of the support on all the metal elements is a complex operation because the molding operation is critical given the precision of positioning of the metal elements. The mold is complex, because the plastic material must not cover the connection tabs, and the metal elements must be positioned precisely in this mold.

There is a need to benefit from a connection device which is reliable and which meets the requirements of large-scale industrial production, such as in the automobile, by being in particular easy to manufacture and to use.

There is also an interest in having a connection device which makes it possible to simplify the connection to a supply bus of the stator.

There also remains a need for a connection device making it possible to simplify the production of the windings of the stator and/or to gain in compactness.

• Des éléments métalliques périphériques comportant chacun au moins une patte de connexion à un conducteur de bobinage stator, cette patte présentant une gorge ouverte radialement vers l’extérieur pour recevoir le conducteur, cette gorge étant de préférence délimitée au moins partiellement par un bord tombé, de préférence orienté radialement, au moins certains de ces éléments métalliques périphériques comportant en outre au moins une patte de connexion à un bus d’alimentation du stator, au moins une partie des éléments métalliques comportant des portions curvilignes reliant les pattes de connexion entre elles,
• un support isolant de maintien des éléments métalliques, comportant de préférence des logements de réception des éléments métalliques.

The invention aims to meet all or part of these needs and has as its object, according to a first of its aspects, a connection device for a stator, comprising:

• Peripheral metal elements each comprising at least one lug for connection to a stator winding conductor, this lug having a groove open radially outwards to receive the conductor, this groove preferably being delimited at least partially by a flanged edge, preferably radially oriented, at least some of these peripheral metal elements further comprising at least one connection lug to a supply bus of the stator, at least some of the metal elements comprising curvilinear portions connecting the connection lugs together,
• an insulating support for holding the metal elements, preferably comprising housings for receiving the metal elements.

The connection device according to the invention makes it possible to easily connect the conductors of the coils to each other and/or to the terminals of the power supply bus, the number of these terminals being typically equal to the number of phases. The orientation and shape of the connection lugs intended to be connected to the winding conductors allows easy and reliable connection of the windings. The strand or strands of a conductor can engage in the aforementioned groove, preferably with clearance so as to facilitate the insertion of the conductors into the corresponding tabs. All the conductors can be placed in the grooves provided for this purpose on the legs of the metal elements, and thus prepositioned pending welding. The welds can then be made using a tool which presses the conductors against the fallen edges. The presence of the grooves limits the risk of incorrect positioning of the conductors at the time of welding, and can facilitate the action of the welding tool. With the flanges, we have a relatively large contact surface between the conductors and the lugs, conducive to good quality electrical contact and good mechanical resistance, in particular with respect to vibrations. The flange is preferably formed by a bent portion at right angles. One then takes advantage of the space freed by the formation of the bend to make the groove, the width of the raised edge preferably corresponding substantially to the width of the groove minus the thickness of the metal sheet from which the element was realized.

The section of the inserted conductor can be rectangular, the conductor being solid or multi-strand. Each supply bus connection lug is preferably rigidly linked to the rest of the corresponding metal element. The number of connection lugs to the conductors of the winding is for example 6, and that of the connection lugs to the power supply bus equal to the number of phases, in particular 3, the number of phases of the machine not being however limited. to 3 and may be other, in particular greater than 3.

The power bus connection tabs can be aligned in a plane or arranged in an arc of a circle. An arrangement in an arc of a circle can make it possible to gain in compactness. Legs can be in the form of connecting rings, if required.

The connection device can ensure a star or delta connection of the phases of the stator. One can provide the same insulating support, on which the metallic elements are fixed in a predefined way according to the star or triangle mounting. This makes it possible to reuse the same insulating support to manufacture connection devices suitable for a star connection and others suitable for a delta connection.

Preferably, the connection device comprises metal belt elements, radially inside said peripheral metal elements, held by the insulating support and each having two free ends for connection to one or more conductors of the stator. These metal belt elements simplify the production of the windings by avoiding having to extend certain conductors of the coils out of the notches of the stator to ensure electrical continuity between the conductors engaged in certain notches. The metal belt elements are for example 3 in number. The invention makes it possible to take advantage of the presence of the support to maintain the metal belt elements at the appropriate locations.

The connection ends of each metal belt element preferably each have a groove oriented in the circumferential direction. This groove is preferably sufficiently narrow to obtain clamping of the conductor inserted inside, as soon as it is inserted into the groove.

Preferably, the support comprises a nut holder comprising housings and associated nuts, retained in these housings, intended to receive assembly screws of the power supply bus on the connection lugs to the latter. The power supply bus can include a plug with three terminals consisting of rigid connection lugs, parallel to each other, each traversed by a hole allowing the passage of a fixing screw on the nut holder. These three terminals can be coplanar. The plug can be connected to a connection cable to power electronics.

The bracket can span less than a full turn, which helps make the stator compact. The connection device is arranged at an axial end of the stator. The latter is preferably a stator radially external to the rotor.

Preferably, the support is formed from a single piece of plastic material. As a variant, the support comprises several assembled parts. The support can be produced by injection molding of thermoplastic material, or otherwise, for example by machining or by an additive manufacturing technique.

The support is preferably prefabricated before the installation of at least one of the metal elements on the support, and in particular of all the metal elements on the support. This avoids the use of a complex mould. The radial orientation of the lugs and the grooves for receiving the peripheral metal elements is compatible with the mounting of the metal elements on the support.

The support may comprise grooves open radially inwards to accommodate the peripheral metal elements, openings emerging radially on the outside being provided for the passage of the connection lugs to the conductors of the winding. These peripheral metal elements can be introduced radially into said grooves, by a movement directed from the inside to the outside.

Preferably, the support is arranged to retain the metal elements by snap-fastening. This avoids the use of screws and simplifies the assembly operation. The support may include retaining lugs by snap-fastening the metal elements, made in one piece with the support. At least one of the metal elements may also include at least one relief adapted to snap onto the support. For example, the aforementioned connection lugs engaged through the openings of the support have teeth which hook onto the edge of the support once the opening has been crossed.

The support may comprise at least two grooves located at different heights on the support, to receive the peripheral metal elements.

The support may include a third groove offset in height relative to the other two and radially more internal than the other two, to receive the metal belt elements.

As a variant, at least one of the peripheral or belt metal elements can be introduced into the support by moving it in the circumferential direction therein, the metal element then comprising, preferably, a relief ensuring its retention radially on the support once engaged in it.

The peripheral metal elements can alternatively be held by screws on the support.

• Des éléments métalliques périphériques comportant chacun au moins une patte de connexion à au moins un conducteur de bobinage stator, au moins certains de ces éléments métalliques périphériques comportant en outre au moins une patte de connexion à un bus d’alimentation du stator,
• des éléments métalliques de ceinture, destinés à relier des conducteurs de bobinage stator, les éléments métalliques de ceinture étant radialement décalés par rapport aux éléments métalliques périphériques, notamment leur étant radialement intérieurs,
• un support isolant de maintien des éléments métalliques périphériques et de ceinture, comportant de préférence des logements de réception des éléments métalliques.

A further subject of the invention, according to a second of its aspects, independently or in combination with the foregoing, is a connection device for a stator, comprising:

• Peripheral metal elements each comprising at least one connection lug to at least one stator winding conductor, at least some of these peripheral metal elements further comprising at least one connection lug to a power supply bus of the stator,
• metal belt elements, intended to connect stator winding conductors, the metal belt elements being radially offset with respect to the peripheral metal elements, in particular being radially inside them,
• an insulating support for holding the peripheral and belt metal elements, preferably comprising housings for receiving the metal elements.

According to this second aspect of the invention, the connection lugs to the conductors of the stator winding are not limited to a particular shape. The presence of metal belt elements avoids having to make some of the stator winding conductors with relatively long portions extending outside the magnetic circuit of the stator, which simplifies the production of the winding and makes it possible to gain in compactness. . This also simplifies the realization of the pins when the winding is carried out with pins. The metallic belt elements provide a bridge between certain pins in a particularly compact way, taking advantage of the free space present on the radially inner side of the metallic elements used for the connection to the power supply bus. All the features set out above in connection with the first aspect of the invention can be included in this second aspect of the invention.

• Des éléments métalliques périphériques comportant chacun au moins une patte de connexion à au moins un conducteur de bobinage stator, au moins certains de ces éléments métalliques périphériques comportant en outre au moins une patte de connexion à un bus d’alimentation du stator,
• un support isolant de maintien des éléments métalliques, ce support étant réalisé avec un porte-écrou, ce porte-écrou comportant des logements définis par le support isolant, dans lesquels sont reçus des écrous respectifs, les pattes de connexion au bus d’alimentation étant disposées relativement auxdits logements de manière à permettre l’établissement d’un contact électrique avec des bornes du bus d’alimentation, maintenues en place au moyen de vis de serrage engagées dans les écrous.

A further subject of the invention, according to a third of its aspects, independently or in combination with the foregoing, is a connection device for a stator, comprising:

• Peripheral metal elements each comprising at least one connection lug to at least one stator winding conductor, at least some of these peripheral metal elements further comprising at least one connection lug to a power supply bus of the stator,
• an insulating support for holding the metal elements, this support being made with a nut holder, this nut holder comprising housings defined by the insulating support, in which respective nuts are received, the connection lugs to the power supply bus being arranged relative to said housings so as to allow the establishment of an electrical contact with the terminals of the power supply bus, held in place by means of clamping screws engaged in the nuts.

According to this third aspect of the invention, the electrical connection to the power supply bus is simplified because the use of an additional terminal block is avoided. It is possible to gain in assembly time and in reliability, the number of component parts to be assembled being reduced. All the characteristics set out above in connection with the first aspect of the invention can be included in this third aspect of the invention. It is possible to avoid the use of flexible wires connected directly to connection tabs on the connection device, and to produce the power supply bus with terminals consisting of rigid metal tabs, which are pressed against the tabs of the connection device and held against them by the screws engaged in the nuts. This makes the positioning of the conductors of the power supply bus more reliable and facilitates the electrical connection.

• Des éléments métalliques périphériques comportant chacun au moins une patte de connexion à au moins un conducteur de bobinage stator, au moins certains de ces éléments métalliques périphériques comportant en outre au moins une patte de connexion à un bus d’alimentation du stator,
• le cas échéant, des éléments métalliques de ceinture, destinés à relier des conducteurs de bobinage stator, les éléments métalliques de ceinture étant décalés radialement par rapport aux éléments métalliques périphériques,
• un support isolant de maintien des éléments métalliques périphériques et des éventuels éléments métalliques de ceinture, comportant des logements de réception des éléments métalliques, au moins l’un des éléments métalliques étant retenu par encliquetage sur le support.

A further subject of the invention, according to a fourth of its aspects, independently or in combination with the foregoing, is a connection device for a stator, comprising:

• Peripheral metal elements each comprising at least one connection lug to at least one stator winding conductor, at least some of these peripheral metal elements further comprising at least one connection lug to a power supply bus of the stator,
• where appropriate, metal belt elements, intended to connect stator winding conductors, the metal belt elements being offset radially with respect to the peripheral metal elements,
• an insulating support for holding the peripheral metal elements and any metal belt elements, comprising housings for receiving the metal elements, at least one of the metal elements being retained by snap-fastening on the support.

According to this fourth aspect of the invention, the fixing of the metal elements is ensured in a reliable manner and compatible with rapid assembly. The support can be made with retaining means such as clamps and/or teeth which deform elastically when the metal elements are inserted into the support in order to retain them thereon. The insertion of the metal elements can be done in the radial direction. Alternatively, or additionally, snap-in reliefs can be made on the metal elements. For example, the connection lugs to the stator winding conductors include at least one tooth which opposes the removal of the element once placed on the support. The latter may include openings through which the lugs are introduced, and at least some of these lugs may include teeth on opposite sides which bear against the edge of the corresponding opening to retain the lug engaged through the opening.

To manufacture the connection device according to this fourth aspect of the invention, the support can be prefabricated, for example by injection molding, and the metal elements are then fixed by snap-fastening on the support. All the characteristics set out above in connection with the first aspect of the invention can be included in this fourth aspect of the invention.

• Des éléments métalliques périphériques comportant chacun au moins une patte de connexion à un conducteur de bobinage stator, au moins certains de ces éléments métalliques périphériques comportant en outre au moins une patte de connexion à un bus d’alimentation du stator, au moins une partie des éléments métalliques comportant des portions curvilignes reliant les pattes de connexion entre elles,
• un support isolant de maintien des éléments métalliques, comportant de préférence des logements de réception des éléments métalliques, le support isolant étant réalisé avec des moyens de positionnement des éléments métalliques permettant l’utilisation de ce support isolant soit pour assurer une connexion étoile, soit pour assurer une connexion triangle des phases du stator.

According to a fifth aspect of the invention, independent or which can be combined with the above, the stator connection device comprises:

• Peripheral metallic elements each comprising at least one lug for connection to a stator winding conductor, at least some of these peripheral metallic elements further comprising at least one lug for connection to a power supply bus of the stator, at least some of the metal elements comprising curvilinear portions connecting the connection tabs to each other,
• an insulating support for holding the metal elements, preferably comprising housings for receiving the metal elements, the insulating support being made with means for positioning the metal elements allowing the use of this insulating support either to ensure a star connection, or to ensure a delta connection of the stator phases.

Such a connection device is advantageous in that it makes it possible to manufacture only one type of insulating support capable of being used for the manufacture of connection devices which can be used either for a delta connection of the phases of the stator, or for a star connection, depending on the locations of the support used to position the metal elements. It is thus possible to reduce the number of references necessary for the manufacture of the connection devices and to benefit from an economy of scale.

• Des éléments métalliques périphériques comportant chacun au moins une patte de connexion à un conducteur de bobinage stator, au moins certains de ces éléments métalliques périphériques comportant en outre au moins une patte de connexion à un bus d’alimentation du stator, au moins une partie des éléments métalliques comportant des portions curvilignes reliant les pattes de connexion entre elles,
• un support isolant de maintien des éléments métalliques selon au moins deux couches d’éléments situées à des positions axiales différentes sur le support.

According to a sixth aspect of the invention, independent or which can be combined with the above, the stator connection device comprises:

• Peripheral metallic elements each comprising at least one lug for connection to a stator winding conductor, at least some of these peripheral metallic elements further comprising at least one lug for connection to a power supply bus of the stator, at least some of the metal elements comprising curvilinear portions connecting the connection tabs to each other,
• an insulating support for holding the metal elements according to at least two layers of elements located at different axial positions on the support.

Such an arrangement makes it possible to gain in compactness while ensuring the number of connections necessary between the conductors of the winding. For example, the number of layers is two, the insulating support comprising two grooves located at different heights, each of which can accommodate one or more metal elements. In a variant, the number of grooves is three, making it possible to accommodate peripheral and belt metal elements on three levels.

• Des éléments métalliques périphériques comportant chacun au moins une patte de connexion à un conducteur de bobinage stator, cette patte présentant au moins un bord tombé orienté radialement, définissant une surface de connexion à un conducteur du stator, au moins certains de ces éléments métalliques périphériques comportant en outre au moins une patte de connexion à un bus d’alimentation du stator, au moins une partie des éléments métalliques comportant des portions curvilignes reliant les pattes de connexion entre elles,
• un support isolant de maintien des éléments métalliques, comportant de préférence des logements de réception des éléments métalliques.

According to a seventh aspect of the invention, independent or which can be combined with the above, the stator connection device comprises:

• Peripheral metal elements each comprising at least one lug for connection to a stator winding conductor, this lug having at least one flanged edge oriented radially, defining a connection surface to a conductor of the stator, at least some of these peripheral metal elements comprising furthermore at least one connection lug to a supply bus of the stator, at least some of the metal elements comprising curvilinear portions connecting the connection lugs to each other,
• an insulating support for holding the metal elements, preferably comprising housings for receiving the metal elements.

The flanged edge provides a larger contact surface for fixing a stator conductor, and its radial orientation facilitates the positioning and soldering operation of the conductor, even when the conductor has limited flexibility.

Another subject of the invention is an electric machine stator comprising a winding whose conductors are connected to a connection device according to the invention, as defined above. This connection device can be according to any one of the different aspects of the invention mentioned above.

The winding can have I or U pins.

The winding may include conductors connected to the metallic belt elements.

The stator may be wave-wound or otherwise.

Another subject of the invention is a process for manufacturing a stator according to the invention, in which the conductors of the coils are all placed in the connection lugs of the metal elements before being welded thereto.

schematically represents an example of a connection device produced in accordance with the invention,

represents in isolation the insulating support of the connection device of Figure 1,

illustrates the assembly of the components of the connection device of Figure 1,

is a schematic section of the connection device,

is a view similar to FIG. 1 of a variant of a connection device,

is a view similar to FIG. 1 of another variant of a connection device,

represents the nut carrier equipped with screws,

represents an example of retaining means,

represents a detail of the device of figure 6,

is a schematic section of the device of Figure 5,

illustrates the connection of the connection device to a power bus,

illustrates an alternative embodiment of means for holding the metal elements in the support,

illustrates a variant of mounting the metal elements in the support,

represents a detail of the device of figure 13,

is a view similar to FIG. 14, of an alternative embodiment of the retaining means,

is a view similar to Figure 1 of an alternative embodiment of the connection device of Figure 1,

represents a stator equipped with a connection device according to the invention,

represents an embodiment detail of a connection lug, and

represents a stator equipped with a connection device such as that of FIG. 1,

represents a connection tab having at least one dropped edge,

illustrates an arrangement of the connection terminals to the power supply bus according to an arc of a circle,

illustrates the connection of the phases according to a star connection, and

illustrates the connection of the phases according to a delta connection.

detailed description

The connection device 1 represented in FIG. 1 comprises an insulating support 10 and metal elements 20 carried by this support 10.

The support 10 is produced in the example considered by molding of thermoplastic material, in a monolithic manner, but the invention is not limited to a particular technique for manufacturing the support and the latter can also be produced by an additive manufacturing technique. or by machining, of a plastic material or any other electrically insulating material.

The support 10 is shown in isolation in Figure 2. It is preferably prefabricated, then the metal elements are placed on it, as shown in Figure 3.

The support 10 has an incomplete circular shape, and extends around the axis of rotation of the rotor over, for example, more than 270°. The angular opening of the support 10 is for example more than 90°, as illustrated.

The support 10 is made with two grooves 12 and 13 separated by a rib 11. The grooves 12 and 13 open out onto the radially outer surface of the support through openings 15.

The metal elements 20 consist in the example shown of two elements each comprising a portion in the arc of a circle 21 connecting a tab 22 for connection to a conductor of the stator winding to a tab 23 for connection to a supply bus of the stator, a short element without a portion 21 and an element with three legs 22 and a portion 21 but without a leg 23.

The tabs 22 are oriented radially and come out through the openings 15 of the support 10.

The tabs 23 are bent a first time at right angles at their connection to the arcuate portion 21, then a second time at right angles radially outwards.

The metallic elements 20 are formed by cutting and bending a plate of an electrically conductive material, preferably copper.

To assemble the device 1, one proceeds as illustrated in FIG. 3 by inserting the elements 20 into the grooves 12 and 13.

The total thickness e of the device 1 is for example less than 15 mm, being for example 13 mm, for elements 20 made in a plate, for example of copper or aluminum, of thickness t of between 2.5 and 3.5mm, for example 3mm thick.

Each lug 22 has a groove 26, open radially outwards, intended to receive one or more strands of an electrical conductor of the stator windings.

In exemplary embodiments, groove 26 is relatively narrow, being elongated in the radial direction. Its width w may correspond to the thickness of the strand or strands intended to be connected, or even be slightly less, so that this or these strands are received tightly in the tab before they are welded thereto.

The groove 26 can alternatively be wider.

The groove 26 is formed between two branches 27, at least one of which, and preferably both, preferably have, as illustrated, oblique edges 28 converging inwards, to facilitate the insertion of the strand(s) between the branches.

In Figure 20, there is illustrated the possibility for the connection tabs 22 to have at least one flange 120, formed by a bent portion at right angles to the tab 22. Preferably, as shown, the bent portion 120 is extends axially in the opposite direction to the stator winding. It can also be seen in this figure 20 that the flange 120 is oriented radially, like the lug 22. The width of the groove 26 is greater than the thickness of the end E of the conductor engaged inside. The conductor is preferably fixed by its flat on the face 121 of the flange turned towards the groove 26. The width of the groove 26 corresponds to the height of the flange, minus the thickness of the sheet from which this edge is realized. The latter is formed by cutting the leg 22 and straightening the portion thus cut at right angles, around a folding axis parallel to the longitudinal axis of the leg 22. The branches 27 can be of unequal widths, as illustrated , the branch 27 carrying the flange 120 may be wider than the other, as shown. All the tabs 22 having an end as shown in Figure 18 can advantageously be replaced, in examples not shown, by a tab as shown in Figure 20.

In another variant not shown, the leg 22 of FIG. 20 comprises only the branch 27 carrying the flange. In this case, the lug 22 no longer forms a groove 26 open radially outwards. The presence of the flange nevertheless offers a larger fixing surface than in the case of the example of figure 18, without flange. All the examples shown with tabs 22 such as that illustrated in FIG. 18 can be modified with tabs 22 having a flanged edge, according to this variant not shown.

In Figure 5 there is shown an alternative embodiment of the device 1 which differs from the previous one by the presence of additional metal elements 30, called belt, carried by the support 10.

Each metal belt element 30 has an arcuate portion 31, in an arc of a circle, and two lugs 32 at the end, each lug 32 having a shape similar to that of the lugs 22 but with a groove 33 oriented in the circumferential direction. This groove 33 is formed between two branches like the legs 22, these branches having oblique edges at the end, converging inwards.

The metal belt elements 30 are received in a third groove 16 of the support 10, offset from the two others in the direction of the height and radially more internal, as visible in FIGS. 5 and 10. The bottom of the groove 16 can be radially more interior than rib 1, as can be seen in Figure 10.

The support 10 may have, on one side, a chamfered edge 18, as shown in Figures 5 and 10.

The total height m of the support 10 can be less than or equal to 20 mm, and for example between 16 and 18 mm

In the example of Figure 5, the device 1 comprises three metal belt elements, each with the same angular extent. One of the tabs 32 may protrude from one end of the device 1, as shown. Each element 30 has at least one tab 32 directed towards a tab 32 of another element 30. The elements 30 are preferably made like the elements 20 by cutting out a plate of an electrically conductive material such as copper, with the same thickness, for example 3mm.

There is shown in Figure 6 a device 1 according to another implementation variant of the invention.

This example illustrates the possibility of making the device 1 with a nut holder 40, shown more particularly in Figure 7.

This nut carrier 40 comprises a boss 41 extending from the arcuate body of the support 10, this boss defining three housings 42 each receiving a nut 43.

Legs 23 bear against the top of boss 41. Screws 44 pass through the part of lugs 23 resting on boss 41 and engage in nuts 43.

The screws 44 are used to fix a connector 50 of the stator power supply bus, visible in figure 11, comprising three terminals 51 intended to be tightened against respective lugs 23 by the screws 44.

Retaining means may be provided on the support 10 to retain the metal elements attached thereto.

These retaining means may comprise reliefs molded with the rest of the support, for example elastic clamps 50 as illustrated in FIG. 8. These clamps 50 each comprise two branches forming between them a groove for receiving the metal element of belt 30, and provided on their facing faces with teeth which snap onto the arcuate portion of the element, the flat of which is oriented perpendicular to the axis of rotation of the rotor.

The retaining means may also comprise snap-in reliefs made on the metal elements 20 and/or 30, as illustrated in Figure 9.

In this figure, we see that we can make a tab 22 with teeth 55 which hook onto the outer surface of the support 10 after passing through the corresponding opening 15.

There is illustrated in Figure 12 the possibility of providing the support 10 with retaining teeth 58 on which the metal elements 20 snap into place once inserted into the bottom of the grooves 12 or 13. The radially inner edge of the elements 20 is held by the teeth 58, at the end of the insertion of the elements 20. During the insertion, the teeth 58 can deform elastically to allow the crossing of these by the element.

The support 10 can also be made in such a way as to allow the metal elements to be put in place by sliding in a circumferential direction, as illustrated in FIG. 13.

In this example, at least one groove for receiving the metal elements is open radially outwards, so as to allow passage for the tabs 22.

Each metal element 20 can be retained in this groove due to its section and that of the groove, chosen to prevent radial outward movement of the metal element, while allowing movement in the circumferential direction.

For example, as illustrated in Figure 14, the element 20 can be made with a groove and the support 10 with a rib 60 engaged in this groove.

Alternatively, as illustrated in Figure 15, the element 20 is made with a return or a rib 62, engaged in a corresponding groove 63 of the support 10.

Preferably, the support 10 is made monolithically, as in the examples which have just been described.

However, as a variant, the support 10 can be produced by assembling several parts made of insulating material, in particular of plastic material.

In the example of Figure 16, the support 10 comprises two parts 70 and 72 assembled for example using screws.

Certain metal elements 20 can be arranged between parts 70 and 72.

The lugs 23 can be formed in the plane of the elements 20. Two elements 20 can include holes 73 which coincide with holes made in the parts 70 and 72 for the passage of fixing screws for two of the terminals of the power supply bus. A third element 20 includes a hole 74 and part 72 a notch 76 for receiving the third terminal of the power supply bus.

The stator is preferably three-phase, but the invention is not limited to a particular number of phases.

The stator winding may be "wavy" or otherwise. The term "wavy winding" denotes a winding in which the electrical conductors of the same phase are electrically connected to each other so that the electric current of the phase circulates in the electrical conductors by rotating around the axis of rotation of the machine always in one direction.

The magnetic circuit of the stator preferably comprises closed slots.

To manufacture the stator, one begins by realizing the winding of the magnetic circuit by inserting the pins in the notches of the stator mass. Each pin may be U-shaped ( "U-pin" in English) or right, being I-shaped ( "I-pin" in English).

The pins do not require having open notches, we can have closed notches which allow to hold the pins and we can thus avoid a step of inserting wedges to close the notches of the stator.

The electrical conductors can be introduced into the corresponding slots by one or both axial ends of the machine.

An I-shaped electrical conductor has two axial ends each placed at one of the axial ends of the stator. It passes through a single notch, and can be welded at each of its axial ends to two other electrical conductors, at the axial ends of the stator.

A U-shaped electrical conductor has two axial ends both placed at one of the axial ends of the stator. It passes through two different notches, and can be welded at each of its axial ends to two other electrical conductors, at the level of the same side of the stator. The bottom of the U is placed on the other side of the stator.

Each electrical conductor may comprise one or more strands (“ wire ” or “ strand ” in English). By "strand" is meant the most elementary unit for electrical conduction. A strand can be of round cross section, we can then speak of 'thread', or flat. The flat strands can be shaped like a hairpin, for example U or I.

The fact that each notch can comprise several conductors and/or several strands makes it possible to minimize the losses by induced currents, or AC Joule losses, which evolve with the square of the supply frequency, which is particularly advantageous when the operating speed is high.

The electrical conductors are preferably arranged in a row in the notches. By "row", it is meant that the electrical conductors are not arranged in the loose slots but in an orderly manner. They are stacked in the notches in a non-random manner, being for example arranged in one or more rows of electrical conductors aligned, in particular in the radial and/or circumferential direction.

The electrical conductors may be in cross section of generally rectangular shape, in particular with rounded edges. The circumferential dimension of an electrical conductor may correspond substantially to the width of a slot in the stator. Thus, a notch may only have a single electrical conductor across its width. The width of the notch is measured in its circumferential dimension around the axis of rotation of the machine.

The electrical conductors can be adjacent to each other by their long sides, the long side also being called "flat".

The optimization of the stack can make it possible to place a greater quantity of electrical conductors in the slots and therefore to obtain a stator of greater power, at constant volume.

In one embodiment, each electrical conductor may comprise one or more pins, each forming a strand, as explained above. In this case, all the strands of the same electrical conductor can be electrically connected to each other at the exit from the notch. The strands electrically connected to each other are placed in short circuit. The number of strands electrically connected together can be greater than or equal to 2, being for example between 2 and 12, being for example 3, 4, 6 or 8 strands.

Several strands can form the same electrical conductor. The same electric current of the same phase circulates in all the strands of the same electrical conductor. All the strands of the same electrical conductor can be electrically connected to each other, in particular at the exit from the notch. All the strands of the same electrical conductor can be electrically connected to each other at each of their two axial ends, in particular at the exit from the notch. They can be electrically connected in parallel.

All the strands of all the electrical conductors having a free end located at the same circumferential position around the axis of rotation of the machine, whatever their radial position, can be electrically connected to each other.

In one embodiment, each electrical conductor has a single strand. In another embodiment, each electrical conductor has three strands.

In the case where a notch comprises two electrical conductors, a notch can accommodate two strands, or as a variant six strands, for example distributed between the two electrical conductors.

Alternatively, a slot has four electrical conductors. Each electrical conductor may comprise two strands. The notch then houses eight strands, distributed between the four electrical conductors.

The strands can be positioned in the notch so that their circumferential dimension around the axis of rotation of the machine is greater than their radial dimension. Such a configuration allows a reduction of losses by eddy currents in the strands.

A strand can have a width of between 1 and 5 mmm, being for example of the order of 2.5 or 3 mm. The width of a strand is defined as its dimension in the circumferential direction around the axis of rotation of the machine.

In Figure 17 there is shown a stator 100 equipped with a connection device 1 according to the invention.

The stator 100 comprises a magnetic circuit comprising notches traversed by the windings. The latter are formed by U- or I-shaped pins.

The conductors of the winding are for example multi-stranded and each comprise, for example, as illustrated, three superposed strands and electrically connected together.

Once the conductors of the winding are in place, the ends E of the conductors are engaged in the lugs 22 provided for this purpose on the connection device 1. The conductors can then be welded to the lugs by any suitable welding technique, for example by laser welding, or brazing. Then the stator can be impregnated with resin.

We see in Figure 17 the ends E of these conductors, about to be inserted into the grooves 26 of the tabs 22 intended to receive them. When the tabs 22 have a flanged edge 120, each end E is welded against this flanged edge.

There is shown in Figure 19 a stator variant equipped with a connection device 1 such as that of Figure 1, without metal belt elements. The ends E of the conductors are shown before their insertion into the lugs 22.

In Figure 21, there is illustrated the possibility of making the connection lugs 23 with a non-linear arrangement, in this case an arrangement in an arc of a circle of the axes of the passages for the fixing screws of the terminals of the power supply bus. In this example, it is further seen that the tabs 23 can each have an annular shape around the corresponding passage.

The connection device according to the invention can be made in such a way as to ensure a triangle connection, as illustrated in figure 23, or a star connection, as illustrated in figure 22

The examples illustrated in these figures correspond to three-phase machines, but the invention encompasses machines with a greater number of phases.

It can be seen in these figures that the stator has six conductors whose ends E are fixed to the connection device according to the invention.

These ends E are on the opposite side to the welds between the pins of the stator.

Among these six ends, three correspond to inputs, and three to phase outputs, which are connected differently depending on whether the assembly is star or delta, as illustrated.

In the star connection, the three outputs are connected together by the same metal element 20 of the connection device, while in the delta connection, each input is connected to an output by a corresponding metal element 20.

Of course, the invention is not limited to the examples which have just been described.

For example, the shape of the metal elements 20 or 30 and that of the support 10 can be modified according to the way in which the outputs of the conductors of the windings are arranged.

For the aspects of the invention where the support is not prefabricated, the support can be molded over all or part of the metal elements.

Claims (24)

Connection device (1) for a stator, comprising:

• Peripheral metal elements (20) each comprising at least one lug (22) for connection to at least one stator winding conductor (E), this lug having a groove (26) open radially outwards to receive the conductor, this groove (26) being delimited at least partially by a flange (120), preferably oriented radially, at least some of these peripheral metal elements (20) further comprising at least one lug (23) for connection to a bus power supply to the stator, at least part of the metal elements (20) comprising curvilinear portions (21) connecting the connection lugs to one another,
• an insulating support (10) for holding the metal elements, preferably comprising housings for receiving the metal elements.

Connection device for a stator, comprising:

• Peripheral metallic elements each comprising at least one lug for connection to at least one stator winding conductor, at least some of these peripheral metallic elements further comprising at least one lug (23) for connection to a power supply bus of the stator,
• metal belt elements, intended to connect stator winding conductors, the metal belt elements being radially offset with respect to the peripheral metal elements, in particular being radially inside them,
• an insulating support for holding the peripheral and belt metal elements, preferably comprising housings for receiving the metal elements.

Connection device for a stator, comprising:

• Peripheral metal elements each comprising at least one connection lug to at least one stator winding conductor, at least some of these peripheral metal elements further comprising at least one connection lug to a power supply bus of the stator,
• an insulating support for holding the metal elements, this support being made with a nut holder, this nut holder comprising housings defined by the insulating support, in which respective nuts are received, the connection lugs to the power supply bus being arranged relative to said housings so as to allow the establishment of an electrical contact with the terminals of the power supply bus, held in place by means of clamping screws engaged in the nuts.

Connection device for a stator, comprising:

• Peripheral metal elements each comprising at least one connection lug to at least one stator winding conductor, at least some of these peripheral metal elements further comprising at least one connection lug to a power supply bus of the stator,
• where appropriate, metal belt elements, intended to connect stator winding conductors, the metal belt elements being offset radially with respect to the peripheral metal elements,
• an insulating support for holding the peripheral metal elements and any metal belt elements, comprising housings for receiving the metal elements, at least one of the metal elements being retained by snap-fastening on the support.

Connection device for a stator, comprising:

• Peripheral metallic elements each comprising at least one lug for connection to a stator winding conductor, at least some of these peripheral metallic elements further comprising at least one lug for connection to a power supply bus of the stator, at least part of the metal elements comprising curvilinear portions (21) connecting the connection tabs to each other,
• an insulating support (10) for holding the metal elements, comprising housings for receiving the metal elements, the insulating support being made with means for positioning the metal elements allowing the use of this insulating support (10) either to ensure a connection star, or to ensure a delta connection of the stator phases.

Connection device for a stator, comprising:

• Peripheral metallic elements each comprising at least one lug for connection to a stator winding conductor, at least some of these peripheral metallic elements further comprising at least one lug for connection to a power supply bus of the stator, at least part of the metal elements comprising curvilinear portions connecting the connection tabs to each other,
• an insulating support (10) for holding the metal elements in at least two layers of elements located at different axial positions on the support.

Connection device for a stator, comprising:

• Peripheral metal elements each comprising at least one lug for connection to a stator winding conductor, this lug having at least one flanged edge (120) oriented radially, defining a connection surface to a conductor of the stator, at least some of these elements metallic peripherals further comprising at least one connection lug to a power supply bus of the stator, at least some of the metal elements comprising curvilinear portions connecting the connection lugs to one another,
• an insulating support (10) for holding the metal elements, preferably comprising housings for receiving the metal elements.

Device according to any one of Claims 1 to 7, with the exception of Claim 2, comprising metallic belt elements (30), radially inside the said peripheral metallic elements (20), held by the insulating support (10) and each having two free ends (32) for connection to one or more conductor strands of the stator. Device according to Claim 8, the connection ends (32) of each metal belt element (30) each having a groove (33) oriented in the circumferential direction. Device according to any one of the preceding claims, the support (10) comprising a nut holder (40) comprising housings (42) and associated nuts (43), retained in these housings, intended to receive screws (44) assembly of the power bus on the connecting tabs (23) to the latter. A device according to any preceding claim, the support extending for less than one full turn. Device according to any one of the preceding claims, the support (10) being formed from a single piece of plastic material, or as a variant comprising several pieces (70, 72) assembled together. Device according to Claim 12, the support being prefabricated before the positioning of at least one of the metal elements on the support, and in particular of all the metal elements on the support. Device according to claim 13, the support comprising grooves (12, 13) open radially inwards to accommodate the peripheral metal elements (20), openings (15) emerging radially on the outside being provided for the passage of the tabs (22) for connection to the conductors of the winding. Device according to Claim 14, the support (10) being arranged to retain the metal elements by snap-fastening. Device according to claim 15, the support comprising lugs (50; 58) for retaining the metal elements by snap-fastening, made in one piece with the support. Device according to one of Claims 1 to 16, the support comprising at least two grooves (12, 13) located at different heights on the support, to receive the peripheral metal elements (20). Device according to Claims 8 and 17, the support comprising a third groove (16) offset in height with respect to the other two and radially more internal than the other two, to receive the metal belt elements (30). Device according to any one of the preceding claims, at least one of the peripheral or belt metal elements being introduced into the support by moving it in the circumferential direction therein, the metal element preferably comprising a relief (62 ) ensuring its retention radially on the support once engaged therein. Device according to any one of Claims 1 to 18, the peripheral metal elements being held by screws on the support. Stator (100) of an electric machine comprising a winding whose conductors are connected to a connection device (1) according to any one of the preceding claims. Stator according to Claim 21, the winding comprising I-shaped or U-shaped pins. Stator according to one of Claims 21 or 22, the winding comprising conductors connected to the metallic belt elements (30). Method of manufacturing a stator according to one of Claims 21 to 23, in which the conductors (E) of the winding are all placed in the connection lugs (22, 32) of the metal elements before being welded thereto .