Method for attaching teeth of stator to housing

Abstract

Disclosed is an element (5) of an electric machine, having a planar assembly face (11) intended to be attached by glue to a planar assembly face of another element of the electric machine, said element (5) being characterised in that it comprises at least two ribs (17), the at least two ribs are arranged to protrude from the planar assembly surface (11) and have the same height measured perpendicular to the planar assembly surface (11) along the entire length of the planar assembly surface.

Description

Field of the Invention

[0001] The present invention relates to the architecture of stator teeth or housings in axial flux rotating electrical machines, particularly of the permanent magnet type, for their assembly. Background Art

[0002] As is known per se, a rotating electrical machine has a stator fixed to a housing and a rotor fixed to a shaft. The rotor can be fixed to a drive shaft and / or a driven shaft and can belong to a rotating electrical machine in the form of an alternator or an electric motor. The housing is configured to rotatably support the shaft of the rotor, for example by means of rolling bearings.

[0003] The rotor is provided with poles formed, for example, by permanent magnets, while the stator has phase windings typically constituted by coils that are self - closing and wound around teeth.

[0004] In axial flux electrical machines, the stator and the rotor are arranged such that the electromagnetic flux flows parallel to the axis of the rotor. Most axial flux electrical machines include a plurality of stators and / or rotors, each stator and / or rotor having a disc - like shape, and these elements are separated by a gap called the air gap along the axial direction of the axis of the rotor.

[0005] In certain configurations, two stators are arranged, one on each side of the rotor along the axial direction of the axis of the rotor. Thus, each stator can consist only of the teeth attached to the housing and their windings. The present invention relates more particularly to this type of configuration.

[0006] The assembly of the stator teeth on the housing significantly affects the performance of the electrical machine. Specifically, such an assembly can control the air gap between the stator and the rotor. The air gap particularly meets very precise distance constraints so that, in motor mode, the magnetic field formed by the stator can drive the rotor. In addition, the assembly must withstand the stresses (vibrations, temperature, etc.) to which the electrical machine is subjected.

[0007] Furthermore, the assembly also affects the cooling of the components, which, in certain configurations, is carried out by a cooling circuit arranged on the outer face of the housing.

[0008] There are several solutions for assembling the teeth of the stator to the housing. The first solution is to assemble them by screw fastening. However, this solution involves adding material and may require modifying the shape of the cooling circuit for implementation.

[0009] The second solution consists in adhesively bonding the teeth of the stator to the housing. However, using an adhesive between two flat surfaces can cause many problems. Specifically, if the amount of adhesive is uneven, the teeth will be misaligned on the housing and the air gap will be uncontrolled. In addition, bubbles may be generated during assembly, which will result in a reduction in the adhesive bonding surface area and thus a reduction in the strength of the teeth and a decrease in the efficiency of the cooling circuit (since heat exchange will be less ideal).

[0010] Therefore, there is a need for a tooth or housing architecture that can be assembled to the housing by adhesive bonding while maintaining a constant air gap and avoiding the generation of bubbles. Summary of the Invention

[0011] To this end, the present invention proposes an electric machine element having a flat assembly surface intended to be assembled to the flat assembly surface of another element of the electric machine by adhesive bonding. The element includes at least two ribs arranged to project from the flat assembly surface of the element, and the at least two ribs have the same height measured perpendicular to the flat assembly surface over their entire length.

[0012] The technique of adhesively bonding two electric machine elements has the advantage of attaching them without adding components. In addition, the presence of the ribs makes it possible to ensure an adequate adhesive reservoir while minimizing bubbles in order to ensure a complete and optimal adhesive bond between the two elements. Furthermore, since the ribs all have the same height, they can keep the spacing between the two assembled elements the same after adhesive bonding. The adhesive reservoir is determined by the height of the ribs, which can preferably be from 0.2 mm to 0.8 mm.

[0013] The proposed solution is also easy to implement industrially, especially in the case of producing the ribs by stamping.

[0014] Advantageously and non - restrictively, the assembly surface can be defined by a plurality of edges, and the at least two ribs can extend from one edge of the assembly surface to the other edge.

[0015] One advantage is the ability to control the amount of adhesive retained on a relatively large surface area, since the at least two ribs extend from one edge of the assembly surface to the other edge.

[0016] Advantageously and non - restrictively, one rib can be arranged along an edge of the assembly surface, and at least one additional rib can be arranged along the edge on the opposite side of the assembly surface.

[0017] Another advantage is to control the relatively large surface area enclosed by the at least two ribs for the amount of adhesive, making it easier to produce the element, especially when the element is a stator tooth.

[0018] Advantageously and non - restrictively, the at least two ribs may be parallel to each other.

[0019] Advantageously and non - restrictively, the at least two ribs may have a cross - section that is the same in shape over their entire length.

[0020] This enables the adhesive to spread to the same extent along the edges of the ribs. It should be noted that the ribs may have a cross - section that is the same in shape but variable in size over their entire length. This enables, for example, the facing edges of the ribs to remain parallel to each other. Alternatively, the ribs may have a cross - section that is the same in both shape and size over their entire length.

[0021] Generally speaking, it may be simpler to produce identical ribs.

[0022] Advantageously and non - restrictively, each rib may have at least one of the following characteristics:

[0023] - A cross - section in the shape of a quadrilateral, optionally in the shape of a trapezoid, with the first side of the cross - section fixed to the assembly surface, and at least the corner between the second side, which is on the side opposite the first side, and the lateral side connecting them being rounded.

[0024] - A symmetric cross - section with respect to a middle longitudinal plane perpendicular to the assembly surface.

[0025] At least two corners, and even all corners, of the cross - section in the shape of a quadrilateral are rounded. This enables the adhesive present between the top of the rib and the assembly surface of another element to be removed from the sides of each rib when the two elements are pressed, in order to perform adhesive bonding, thus ensuring direct contact without an adhesive layer between the top of the rib and the assembly surface of another motor element.

[0026] This removal can be facilitated by a cross - section in the shape of a trapezoid, with the larger base of the trapezoid fixed to the assembly surface, and at least the corner between the smaller base and the lateral side of the trapezoid being rounded.

[0027] The symmetry of the cross - section itself ensures that the adhesive spreads to the same extent on each side of the rib.

[0028] Advantageously and non - restrictively, the motor element may be selected from stator teeth and a housing.

[0029] Another object of the present invention is a component of a rotating electrical machine, in particular an axial flux electrical machine, the component comprising a plurality of first elements each defining a stator tooth and a second element defining a housing. Each first element has a planar assembly face which is assembled to the planar assembly face of the second element using an adhesive layer, and each first element or the second element among the first elements is an element as described above. Thus, at least two ribs extend between the assembly face of each first element and the assembly face of the second element, and the adhesive layer extends from the assembly face of each first element to the assembly face of the second element, and each rib of the assembly face of one element is in direct contact with the assembly face of that element facing the rib.

[0030] Direct contact should be understood to mean that there is no adhesive in the contact area between the rib and the assembly face of the element facing the rib.

[0031] Advantageously and non - restrictively, each first element defining a stator tooth can be formed by stacking laminations along a stacking direction, each lamination extending perpendicular to the assembly face of the housing. Thus, the at least two ribs can advantageously extend parallel to the stacking direction of the laminations.

[0032] The present invention also relates to a rotating electrical machine, in particular an axial flux rotating electrical machine, the rotating electrical machine comprising a rotor having a rotor disc and a shaft, and two components as described above, wherein the rotor disc is fixed to rotate together with the shaft, and one of the two components is mounted on each side of the rotor disc, the assembly face of the housing of each component faces the rotor disc and the housing of each component is mounted on the shaft via a rolling bearing, and the two housings are assembled to each other.

[0033] The present invention may in particular relate to a motor vehicle equipped with the above - mentioned rotating electrical machine. Description of the Drawings

[0034] Other specific features and advantages of the present invention will become apparent when reading the following description of several specific embodiments of the present invention given by way of indication and not limitation with reference to the accompanying drawings, in which:

[0035] Figure 1 is a cross - sectional view of an axial flux rotating electrical machine.

[0036] Figure 2 is a perspective view of a stator tooth according to an embodiment of the present invention.

[0037] Figure 3 is a perspective view of a stator tooth according to another embodiment of the present invention.

[0038] Figure 4 is a cross - sectional view of a component of a rotating electrical machine according to an embodiment of the present invention.

[0039] ​​​​​Figure 5 is a cross-sectional view of a rib of a member of a rotating electric machine according to an embodiment of the present invention.

[0040] Figure 6 is a cross-sectional view of a rib of a member of a rotating electric machine according to another embodiment of the present invention. Detailed Embodiments

[0041] The present invention relates to an axial-flux rotating electric machine 1 in a motor vehicle.

[0042] Reference Figure 1 , the axial-flux rotating electric machine 1 includes a rotor, which includes a rotor disk 2 that is fixed to rotate together with an output shaft 3. The rotation axis of the shaft 3 extends perpendicular to the rotor disk 2 and passes through the center of the rotor disk. On each side of the rotor disk 2, the electric machine 1 further includes a member 4, which includes a plurality of first elements each defining a stator tooth 5, and the plurality of first elements are assembled to a second element defining a housing 6. The member 4 is separated from the rotor disk 2 by a predetermined fixed distance, which is referred to as an air gap 7.

[0043] The two members 4 are similar and have the same elements. For the sake of clarity, in Figure 1 , only the elements of one member have been denoted by reference numerals, and only one of the members 4 is described in detail in the rest of the specification, and the structure of the other member 4 is the same or similar.

[0044] The metal housing 6 of the member 4 has an inner face 8 and an outer face 9 on the side opposite to the inner face 8. These faces 8, 9 are the faces of the wall 14 of the housing. The housing can be made of any metal or alloy conventionally used for manufacturing housings, such as aluminum. The housing 6 is also mounted on the shaft 3 via a rolling bearing 10.

[0045] The housing 6 has a half-shell shape and thus partially covers the stator 5 and the rotor disk 2. Thus, the housing has a substantially planar wall 14 that defines the inner face 8 and the outer face 9 and extends parallel to the rotor disk 2, and the wall 14 is provided with an outer side wall 15 that forms a face dedicated to coupling with another housing and an inner side wall 16 having a rolling bearing housing. Thus, the two housings located on each side of the rotor disk 2 of the member 4 are assembled to each other through their outer side walls 15. Thus, the inner face 8 (also referred to as the planar assembly face 8) is defined (bounded) by a plurality of edges. Thus, the planar assembly face 8 of each housing faces the face of the rotor disk 2. The rolling bearing 10 is received in the rolling bearing housing of the inner side wall 16 of the member 4 and the corresponding housing of the shaft 3.

[0046] ​In this case, the teeth 5 of the stator are arranged to form a disk, or more specifically a ring, the center of which defines a cylindrical channel for the shaft 3. Thus, said teeth are placed radially with respect to and equidistant from this cylindrical channel.

[0047] The teeth 5 are typically made from a stack of metal laminations 12, each lamination extending perpendicular to the inner face 8 of the housing 6 after assembly. The metal laminations 12 can be formed from any metal or alloy conventionally used for stators, such as an alloy composed of steel and silicon. The teeth 5 of the stator are surrounded by a metal wire 13 so as to form a coil. The metal wire 13 can be made from a metal or alloy suitable for forming a coil (e.g., copper).

[0048] The teeth 5 of the stator also include a planar assembly face 11, which is defined by a plurality of edges and is intended to be adhesively fixed to the inner face 8 of the housing 6 (which is also a planar assembly face 8) by means of an adhesive. In the example shown, the planar assembly face 11 is in the shape of a quadrilateral (in this case a trapezoid) and is thus defined by four edges 11a, 11b, 11c, 11d. However, the present invention is not limited to a particular shape of the planar assembly face. This shape depends in particular on the type of teeth used.

[0049] According to the invention, the teeth 5 of the member 4 are assembled to the associated housing 6 using an adhesive.

[0050] The adhesive used is typically an epoxy resin or a two-component adhesive.

[0051] To optimize the adhesive bonding of these elements, at least two ribs 17 are arranged to project from one of the planar assembly faces 8, 11. Thus, these ribs 17 can separate the planar assembly faces, thereby forming free spaces that can be filled with adhesive. Preferably, there are two ribs, but more ribs can be envisaged, depending on the architecture of the elements to be adhesively bonded.

[0052] These ribs 17 extend from the assembly surface of the element to which they are fixed to the assembly surface of another element. Thus, when the elements 5 and 6 of the assembly member 4 are assembled, the tops of the ribs come into contact with the assembly surface. The ribs 17 have the same height measured perpendicular to the assembly surface to which they are fixed over their entire length. Thus, they are arranged to create one or more free spaces, each free space forming an adhesive reservoir 18 having the same height as them. These reservoirs are formed between the ribs and / or between the ribs and the edges of the assembly surface. Thus, the height of the ribs 17 can be selected based on the amount of adhesive to be applied to achieve optimal assembly, typically selected to be between 0.2 mm and 0.8 mm, preferably between 0.4 mm and 0.6 mm (including the boundary values), for example 0.5 mm. The adhesive reservoir 18 can ensure full adhesive bonding of the teeth to the housing and reduce the risk of bubble formation, since the space formed between the two assembly surfaces can eliminate bubbles when the adhesive is applied. In addition, since the amount of bubbles that may form is reduced, the heat exchange between the stator teeth 5 and the housing 6 is optimized.

[0053] The ribs 17 can be arranged on each assembly surface 11 of a plurality of first elements each defining a tooth 5, or on the assembly surface 8 of the housing 6. Preferably, the ribs 17 are arranged on each of the teeth 5 of the stator, as Figures 2 to 4 shown.

[0054] The ribs 17 themselves are typically made of the same material as the material used to form the assembly surface of the tooth or the assembly surface of the housing. Thus the ribs can be constituted, for example, by metal sheets. When producing the ribs on the teeth, the ribs can be manufactured by stamping.

[0055] Figure 2 Shown is a stator tooth 5 whose assembly surface 11 has two protruding ribs 17, the tooth 5 being intended to be assembled to the assembly surface 8 of the housing 6, as Figure 4 shown. In this embodiment, the ribs are parallel and extend from one edge 11c of the assembly surface 11 to the opposite edge 11a, at a distance from the other edges, which makes it possible to define three adhesive reservoirs 18. These ribs 17 are identical and in this case have a cross-section that is the same in shape and size over their entire length.

[0056] However, the configuration of the ribs is not limited to this example. The ribs 17 can extend from one edge of one of the assembly surfaces 8, 11 to another edge of one of these assembly surfaces 8, 11. Thus, the ribs 17 do not necessarily extend between two edges on opposite sides, but can thus connect two other edges, in particular consecutive edges.

[0057] Reference Figure 3, two ribs 17 are arranged along two edges 11b, 11d on opposite sides of the assembly surface. However, the arrangement of the ribs 17 is not limited to this example. For example, only one of the ribs can be arranged along the edge. In this example, the rib 17 has a cross-section with the same shape along its entire length, but the dimensions of the cross-section gradually increase from one edge 11c of the assembly surface to the other edge 11a. In this case, the ribs 17 are the same, but one rib is symmetrically arranged on each side of the tooth. In this embodiment, therefore, a single adhesive reservoir 18 is formed between the ribs, and in this case, the adhesive reservoir has a rectangular shape. The present invention is of course not limited to the specific shape of the adhesive reservoir. The important point is that the height of the adhesive reservoir is constant.

[0058] The rib 17 preferably extends parallel to the stacking direction of the laminations, as Figure 2 and Figure 3 shown.

[0059] Referring to Figure 5 , the cross-section of the rib 17 can have a rectangular shape, and one side 19 of the rib is fixed to the assembly surface 11. The rib 17 also has a rounded corner between the side 20 (which is on the side opposite to the side 19) and the lateral side 21.

[0060] However, the cross-section of the rib 17 is not limited to this shape. More generally, the cross-section can be in the shape of a quadrilateral, with the first side 19 of the quadrilateral fixed to the assembly surface 11, and the corner between the second side 20 (which is on the side opposite to the first side 19) and the lateral side 21 being rounded.

[0061] Preferably, referring to Figure 6 , the cross-section of the rib 17 can have a trapezoidal shape, with the first side 19 forming the larger base of the trapezoid fixed to the assembly surface 11. The rib 17 also has a rounded corner between the second side 20 (which forms the smaller base and is on the side opposite to the larger base 19) and the lateral side 21.

[0062] The rounded corner enables the adhesive between the smaller base 20 and the assembly surface 8 facing the smaller base to be pushed out, so that direct contact between these two surfaces can be achieved. This enables the adhesive bonding between the two assembly surfaces 8, 11 to each other to be controlled, and thus the distance of the air gap 7 between the teeth 5 of the stator and the rotor 2 to be controlled.

[0063] Finally, in order to control this distance and enable the adhesive to be evenly distributed between and / or around the ribs 17, the ribs preferably have a symmetric cross-section with respect to the intermediate longitudinal plane perpendicular to the assembly surfaces 8, 11 to which these ribs are fixed.

[0064] Generally, the teeth can be assembled to the housing by depositing an adhesive onto the assembly surface that does not have ribs. The assembly is then achieved by placing the two assembly surfaces 8 and 11 together. In this step, the element with ribs can be pressed for a long time until the adhesive is distributed into the reservoir 18 and takes effect. By pressing the element with ribs, the adhesive present on the second side 20 of the ribs will be discharged from this part towards the lateral edges of the ribs. In particular, rounding the corners enables the discharge of the adhesive, which will flow more efficiently and quickly than in the case where the corners are right-angled, thus also facilitating the removal of any air bubbles present.

[0065] In the embodiment described with reference to the accompanying drawings, the ribs are fixed to the assembly surface of the stator teeth. In a variant, these ribs can be produced, for example, by a casting process or by machining, so as to project from the assembly surface 8 of the housing. Thus, it can be proposed to equip the assembly surface 8 of the housing with multiple sets of at least two ribs. Thus, there are as many rib sets as there are teeth to be attached to the housing, and these sets are positioned corresponding to the positions of the stator teeth to be attached to the housing.

[0066] If the ribs are arranged on the assembly surface 8 of the housing, they do not have to extend over the entire length of the housing. However, they can advantageously extend from one edge of the tooth 5 facing its assembly surface 11 to the other edge.

[0067] Thus, regardless of whether the ribs are provided on the assembly surface of each tooth or on the assembly surface of the housing, at least two ribs extend between the assembly surface of each stator tooth and the assembly surface of the housing, thus enabling an adhesive layer to be spread between these assembly surfaces, with the ribs (their tops) in close contact with the assembly surfaces.

[0068] The present invention has been described with reference to an axial flux rotating electrical machine having a rotor and two stators. However, the present invention can be applied to assembling stator teeth to the housing of an axial flux rotating electrical machine with a different structure, or even to a radial flux rotating electrical machine, or to another element for supporting the teeth.

Claims

1. A motor (1) component (5, 6) having a planar assembly surface (8, 11) intended to be assembled by adhesive bonding to the planar assembly surface (11, 8) of another component (6, 5) of the motor (1). The component (5, 6) is characterized in that it comprises at least two ribs arranged to project from the planar assembly surface (8, 14) of the component and having the same height measured perpendicular to said planar assembly surface (8, 11) over their entire length.

2. The motor (1) components (5, 6) according to claim 1, characterized in that, The assembly surface (8, 11) is delimited by a plurality of edges and is characterized in that the at least two ribs (17) extend from one edge of the assembly surface (8, 11) to another edge.

3. The motor (1) component (5, 6) according to claim 1 or 2, characterized in that, One rib (17) is arranged along an edge of the assembly surface (8, 11) and is characterized in that the at least one additional rib (17) is arranged along the edges on opposite sides of the assembly surface (8, 11).

4. The motor (1) element (5, 6) according to any one of claims 1 to 3, characterized in that, The at least two ribs (17) are parallel to each other.

5. The motor (1) element (5, 6) according to any one of claims 1 to 4, characterized in that, The at least two ribs (17) have the same cross-section shape over their entire length.

6. The motor (1) element (5, 6) according to any one of claims 1 to 5, characterized in that, Each rib (17) has at least one of the following characteristics: - A cross-section in the shape of a quadrilateral, optionally a trapezoid, with a first side (19) of the cross-section fixed to the assembly surface (8, 11) and the corner between at least the second side (20) of the cross-section on the side opposite the first side and the lateral side (21) connecting them being rounded. - A symmetric cross-section with respect to a middle longitudinal plane perpendicular to the assembly surface (8, 11).

7. The motor (1) component (5, 6) according to any one of claims 1 to 6, characterized in that, The motor (1) component is selected from stator teeth (5) and a housing (6).

8. A component (4) of a rotating electrical machine (1), in particular an axial flux electrical machine, the component comprising a plurality of first elements each defining a stator tooth (5) and a second element defining a housing (6), each first element having a planar assembly face (11) which is assembled to the planar assembly face (8) of the second element using an adhesive layer, characterized in that, Each of these first components or the second component is a component as claimed in any one of claims 1 to 7, characterized in that at least two ribs (17) extend between the assembly surface (11) of each first component and the assembly surface (8) of the second component, and characterized in that the adhesive layer extends from the assembly surface (11) of each first component to the assembly surface (8) of the second component, and each rib (17) of the assembly surface (8, 11) of a component is in direct contact with the assembly surface (11, 8) of the component facing the rib.

9. The member (4) according to claim 8, wherein, Each first component defining a stator tooth (5) is formed by stacking laminations (12) along a stacking direction, each lamination (12) extending perpendicular to the assembly surface (8) of the housing. Characterized in that the at least two ribs (17) extend parallel to the stacking direction of these laminations (12).

10. A rotating electrical machine (1), in particular an axial flux rotating electrical machine, comprising a rotor (2) having a rotor disk (2) and a shaft (3), and two members (4) as claimed in claims 8 and 9, wherein, The rotor disc (2) is fixed to rotate together with the shaft (3), and two members (4) are mounted, one on each side of the rotor disc (2). The assembly surface (8) of the housing (6) of each member (4) faces the rotor disc (2) and the housing (6) of each member (4) is mounted on the shaft (3) via a rolling bearing, and the two housings (6) are assembled to each other.

Images