Tool for positioning a stator body
Patent Information
- Application Number
- PCT/EP2026/058470
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-03-25
- Filing Date
- 2026-03-25
- Publication Date
- 2026-10-01
Smart Images
Figure EP2026058470_01102026_PF_FP_ABST
Abstract
Description
DESCRIPTION Title of the invention: Stator body positioning tool
[0001] The present invention relates to the field of axial flux electric machines and more specifically to a tool for positioning a magnetic circuit for an axial flux machine, for example an axial flux electric motor.
[0002] An axial flux electric motor consists of a stator and a rotor. The stationary stator contains electrical coils that generate a magnetic field. The rotor, which rotates around the axis, is equipped with permanent magnets or coils. When electric current flows through the stator coils, it creates a magnetic field that interacts with the rotor magnets, thus generating rotational motion. Unlike traditional radial flux electric motors, the magnetic flux in an axial flux motor moves parallel to the axis of rotation.
[0003] Axial flux motors offer numerous advantages. Their design allows for a significant reduction in size and weight. Furthermore, depending on the speed and load level, such motors can offer good energy efficiency compared to radial flux motors. Finally, the structure of the axial flux motor allows for greater flexibility in machine design.
[0004] Figure 1 is a simplified exploded view of a prior art axial flux electric motor, showing a stator 10 extracted from the housing 20 in which it is intended to be housed. The stator 10 comprises a plate 11, typically made of aluminum, and a stator body 12 which is bonded to the plate 11. The stator body 12, once in position on the plate 11, receives the winding supports 13 around which the copper winding is wound.
[0005] Figure 2 shows a stator body 12 known from the prior art. A stator body, also called a magnetic circuit, is a sheet of steel wound around itself. In other words, the stator body 12 has an annular shape, centered at O, between an inner diameter d1 and an outer diameter d2 (visible in Figure 2B). It is formed from a sheet, or plate, previously cut to the correct dimensions, so that once wound around itself, the sheet forms a succession of stator teeth 151 and notches 152 (visible in Figures 2A and 2C). It is understood from the above that the winding takes place around the center O, between the diameter d1 and the diameter d2. The sheet metal winding is held in the wound position by means of the two weld points 153, 154. The stator body 12, before being glued onto the plate 11, undergoes an annealing step to give it the correct magnetic properties.After this annealing step, the stator body 12 is flexible and does not maintain a fixed shape. In other words, the stator body 12 is easily deformable. Consequently, it is not easy to maintain it in a perfectly circular shape, as illustrated in the left view of Figure 2B. Furthermore, the stator body 12 can take on a shape that varies by several millimeters (illustrated in the right view of Figure 2B), which is incompatible with the dimensional constraints to be observed during the assembly of the components of the axial flux electric machine. After the annealing step, the stator body 12 is bonded to the receiving plate 11. It must be bonded in a predetermined location and according to a geometry specified during the design phase of the electric machine.
[0006] One of the manufacturing challenges that must be faced is therefore related to the handling of the stator body after the annealing stage and more specifically to the correct positioning of the latter on its receiving plate.
[0007] The invention falls within this context and proposes a tool for positioning the stator body on a plate allowing for quick and precise placement of the stator body without damaging it, while ensuring its correct geometric orientation relative to said plate, so as to allow its bonding to a receiving plate.
[0008] To this end, the invention relates to a positioning tool for a circular stator body of a first radius comprising a plurality of stator teeth distributed over its circumference and a plurality of notches, each formed between two adjacent stator teeth, the positioning tool being characterized in that it comprises: A plate having a top surface extending along a first plane, N positioning lugs, N being a natural number greater than 1, arranged on the top surface of the plate, each lug being arranged on a reference circle of radius equal to the first radius and extending longitudinally at least partially along a reference radius of the reference circle, N among the plurality of notches of the stator body being intended to be arranged on the N positioning lugs in an assembled configuration.
[0009] The positioning tool of the invention is designed to cooperate with a stator body in the form of a ring and, in a plane parallel to the first plane, having a circular cross-section. The stator body is characterized by a succession of stator teeth and slots. A slot is formed by one lateral face of a stator tooth and another lateral face of the adjacent stator tooth. The stator teeth are distributed, typically at equal distances from each other, around the circumference of the stator body. In its assembled configuration, the stator body must be positioned so that its circular cross-section has a radius equal to the first radius. In this document, the first radius is chosen to be half the average of the inner and outer diameters mentioned in the introduction. In other words, the first radius corresponds to the radius extending from the center O of the circle to half the length of a slot.The stator body could also be defined by a radius corresponding to either the inner or outer half-diameter. The chosen concept of a first radius highlights the interaction between the stator body and the positioning tool.
[0010] The positioning tool comprises a plate, for example made of aluminum, and a plurality of positioning pins fixed to the plate. A positioning pin is a mechanical part generally parallelepiped in shape, meaning it can be defined by a length, a width, and a height. According to the invention, the positioning tool comprises at least two positioning pins arranged on the upper surface of the plate. Each positioning pin is oriented radially with respect to the center of the plate. More precisely, a reference circle with center O and a radius equal to the first radius is defined on the upper surface of the plate. A reference radius is a radius of the reference circle extending from the center O to a positioning pin. Each positioning pin is therefore partially located on this reference circle and includes a portion extending along a reference radius.The N positioning shims are thus distributed around the circumference of the reference circle.
[0011] Such a positioning tool is suitable for receiving the stator body. In an assembled configuration where the stator body is placed on the positioning tool, the positioning pins rise into the notches of the stator body. Since there are at least two positioning pins, the stator body is correctly positioned angularly. Indeed, the stator body aligns its position with the position of the positioning pins. The combination of the positioning pins' arrangement on the reference circle and their radial orientation ensures that the stator body assumes the required circular shape for its subsequent use in an axial flux machine.
[0012] The reference spokes form an angle with each other. The positioning shims are arranged on the plate so that this angle corresponds to the angle of the angular portion between two notches of the stator body.
[0013] According to an optional feature of the invention, N is equal to 3. In other words, the positioning tool comprises three positioning slats. As explained previously, the three positioning slats are arranged on the reference circle. Two positioning slats are at an angular distance from each other equal to the angular distance between two notches in the stator body. With three positioning slats, the circular shape of the stator body is guaranteed by the contact surfaces between the positioning slats and the faces defining the notches arranged on the positioning slats.
[0014] According to an optional feature of the invention, the reference radii form a 120° angle between each pair. In this configuration, the positioning lugs are equidistant around the reference circle. Thanks to this geometric arrangement of the positioning lugs, the stator body conforms to the circular shape imposed by the complementary shapes of three notches in the stator body and three positioning lugs in the positioning tool.
[0015] According to an optional feature of the invention, the positioning tool further comprises a retaining device for holding the stator body in position on the positioning tool in the assembled configuration. In the assembled configuration, that is, when the stator body is placed on the positioning tool and the N positioning pins of the positioning tool are inserted into N notches in the stator body, the stator body is prevented from rotating about an axis perpendicular to the foreground. Since the positioning pins extend radially on the positioning tool plate, they prevent any translation of the stator body in a plane parallel to the foreground. However, the stator body remains free to translate along an axis perpendicular to the foreground, in the direction away from the positioning tool plate. The retaining device is designed to prevent this translational movement.
[0016] In one variant, it may be a mechanical holding device, for example in the form of claws or clamps that locally grip the positioning tool plate and the stator body.
[0017] In another variant, the holding device can be magnetic. For example, the holding device can comprise magnets arranged around the perimeter of the positioning tool plate, with one surface of each magnet flush with the top surface of the plate. Advantageously, the magnets are at least partially positioned on the reference circle. Each magnet thus opens onto the top surface of the plate between two positioning prongs. In the assembled configuration, a stator tooth of the stator body comes into contact with a magnet. Thanks to this arrangement, the stator body is held against the positioning tool by the magnetic forces of attraction acting between the magnets and the stator body.
[0018] According to an optional feature of the invention, the plate comprises at least N through-holes, preferably arranged on the reference circle; each positioning gib comprises a through-hole; and the positioning tool comprises N fastening devices, each arranged through a through-hole and a through-opening so as to fix the positioning gib to the plate. By way of example, the fastening device may be a threaded rod or a screw-nut assembly.
[0019] Aligning a through-hole in the plate with the through-hole of a positioning pin allows the screw (for example) to be inserted through the through-hole and secured with the nut. This secures the positioning pin against the plate. The positioning pins are therefore removable. Their arrangement on the positioning tool plate can thus be modified to suit the stator body being positioned in a circular shape. In addition to modifying their arrangement, the positioning pins can also be replaced with different sized pins, for example, larger ones if the stator body has wider notches. The positioning tool is fully modular in size and geometry to adapt to the geometry of the stator body it is designed to accommodate.
[0020] It is understood from the above that it is possible to choose a different positioning for the through-holes in the plate, that is, not located on the reference circle. In this case, either the associated positioning pin is offset from the center of the plate, or the through-hole of the positioning pin is also offset from the center of its lower surface and in accordance with the other positioning of the plate's through-hole. A person skilled in the art understands that a through-hole in the plate is positioned opposite a through-hole of a positioning pin, and that the positioning pin is positioned on the plate to accommodate a notch in the stator body.
[0021] According to an optional feature of the invention, the plate comprises at least N upper blind holes opening onto the upper surface of the plate, preferably arranged on a reference radius. Each positioning gib comprises at least one lower blind hole opening onto a lower surface of the positioning gib. The positioning tool comprises N pins, each arranged through an upper blind hole and a lower blind hole so as to orient the positioning gibs along a reference radius on the upper surface of the plate. The spacing between a lower blind hole and the through-hole of a positioning gib is identical to the spacing between an upper blind hole and the through-hole of the plate.
[0022] Securing the positioning gib to the plate with the fastening device may be sufficient to immobilize it relative to the plate. However, depending on the tightening force applied to the fastening device, rotation of the positioning gib relative to the plate around an axis perpendicular to the leading edge remains possible. Given that the stator body is very flexible and fragile, it is crucial that the positioning gibs be correctly positioned, with the correct geometric orientation corresponding to the geometry of the stator body slots. A pin inserted through an upper blind hole in the plate and a lower blind hole in the positioning gib prevents the gib from rotating around the axis perpendicular to the leading edge.Thanks to the positioning of the blind holes on the plate and the positioning pin, the pin allows the exact orientation of the positioning pin along the reference radius on the upper surface of the plate.
[0023] In one variation, the positioning pin may include two lower blind holes arranged on either side of the through-hole, with central symmetry about the through-hole. This feature facilitates mounting the positioning pins on the plate. The pin is placed in the outer blind hole of the plate. Then, the positioning pin is positioned so that its through-hole is opposite the through-hole in the plate. Because the positioning pin has two lower blind holes, it can be positioned on the plate along its reference radius regardless of its orientation. An operator does not need to check the side of the lower blind hole under the positioning pin. One of the two lower blind holes of the positioning pin aligns with the end of the pin. The positioning pin can then be secured to the plate with the fastening device.
[0024] According to an optional feature of the invention, at least one positioning gib comprises, in cross-section along a plane perpendicular to the reference radius along which it extends, two lateral faces, each forming an acute angle with respect to the normal to the foreground. The lateral faces of the positioning gib are inclined with respect to said normal, such that the width of the upper surface of the positioning gib is less than the width of the lower surface of the positioning gib, the lower surface of the positioning gib being the surface in contact with the plate.
[0025] Two adjacent positioning pins form a recess designed to receive at least one stator tooth. More precisely, if the two positioning pins are placed close to each other, at an angular distance from each other equal to the angular distance between two successive notches in the stator body, the two successive notches are designed to be positioned on the two adjacent positioning pins. The recess formed between the two adjacent positioning pins is designed to receive a stator tooth, that is, the one located between the two successive notches.The inclined lateral faces of the positioning pins, and more specifically the lateral face of one of the two positioning pins defining the notch and the other lateral face of the other two positioning pins defining the notch (in other words, the two lateral faces on either side of said notch), form a guide ramp for the stator tooth intended to be inserted between these two positioning pins. The entry surface of the notch housing, which corresponds to the angular sector between the upper surfaces of the two positioning pins, is larger than the bottom surface of the housing, which corresponds to the angular sector between the lower surfaces of the two positioning pins. This results in good guidance of the stator teeth between the positioning pins and thus facilitates the insertion of the stator teeth between the positioning pins.
[0026] According to an optional feature of the invention, the lateral faces of a positioning gib form a right angle with the lower surface of the gib along a first height of the positioning gib, and the lateral faces are inclined along a second height of the positioning gib, between the first height of the positioning gib and the upper surface of the positioning gib. The volume of the housing between two positioning gibs located on the second height of the positioning gibs forms a guide ramp for a stator tooth, while the volume of the housing between two positioning gibs located on the first height of the positioning gibs forms a retention zone for the stator tooth.
[0027] The invention also relates to a positioned assembly formed by a circular stator body of a first radius comprising a plurality of stator teeth distributed around its circumference and a plurality of notches, each formed between two adjacent stator teeth, and the positioning tool described above, N of the plurality of notches in the stator body being arranged on the N positioning slots. It follows from the foregoing that the stator teeth are arranged between two adjacent positioning slots.
[0028] The assembly positioned according to the invention, as described above, also offers advantages similar to those described in connection with the positioning tool according to the invention, which cooperates with the stator body. Other effects and technical advantages will be detailed in the accompanying figures.
[0029] The invention also relates to a method of positioning a stator body on a positioning tool, the stator body being circular of a first radius and comprising a plurality of stator teeth distributed on its circumference and a plurality of notches, each formed between two adjacent stator teeth, the method comprising a step of arranging N among the plurality of notches of the stator body on the N positioning slots of the positioning tool.
[0030] As explained above, the positioning tool is particularly advantageous because it serves as a receptacle for the flexible and fragile stator body. Thanks to the optimized arrangement of the positioning pins on the plate, the positioning tool forms a circular ring composed of these pins and the spaces between them. Each pin aligns with a notch in the stator body. Depending on the angular spacing between two successive pins, the spaces between the pins can accommodate one or more stator teeth. The positioning tool enables precise positioning of the stator body according to a target geometry. This target geometry is achieved through the interaction between the positioning pins and the notches in the stator body.
[0031] The invention also relates to a method of bonding a stator body to a receiving plate, the stator body being circular with a first radius and comprising a plurality of stator teeth distributed around its circumference and a plurality of notches, each formed between two adjacent stator teeth, the method comprising the following steps: Positioning of the stator body on a positioning tool according to the procedure described above; Application of a layer of glue to the upper surface of the receiving plate; Contacting the lower surface of the stator body with the upper surface of the receiving plate to form a pre-assembled plate; Convection cooking of the pre-assembled tray to obtain an assembled tray; Optionally, cooling of the assembled tray; Disassembly of the assembled tray positioning tool.
[0032] By positioning the stator body on the positioning tool, it is ensured that the stator body, which is flexible and not yet rigidly held at this stage of the bonding process, adopts the geometry required for its final use, i.e., a circular geometry. It is also ensured that the angular position of the stator body teeth is correct.
[0033] According to an optional feature of the invention, the bonding process includes, prior to the application of an adhesive layer, a laser etching step of the upper surface of the receiving plate and the lower surface of the stator body. This laser etching step ensures a smooth surface finish on both the upper surface of the receiving plate and the lower surface of the stator body. During the laser etching step, a laser beam scans both surfaces to remove all surface irregularities. This ensures that no small imperfections are present on either surface. This guarantees better adhesion of the adhesive layer to both surfaces.
[0034] Other features and advantages of the invention will become apparent from the following description on the one hand, and from several illustrative and non-limiting examples of embodiments given with reference to the attached schematic drawings on the other hand, in which:
[0035] [Fig. 1] is an exploded and simplified view of a prior art axial flux electric motor;
[0036] [Fig. 2] represents a stator body known from prior art;
[0037] [Fig. 3] schematically represents an example of a tool for positioning a stator body according to the invention,
[0038] [Fig. 4] schematically represents another example of a stator body positioning tool according to the invention;
[0039] [Fig. 5] represents an assembly consisting of a stator body and the positioning tool according to the invention;
[0040] [Fig. 6] schematically represents the steps of a method for gluing a stator body onto a receiving plate according to the invention.
[0041] The features, variations, and different embodiments of the invention, as described or as they will be presented in the detailed description that follows, can be combined in various ways, provided they are not incompatible or mutually exclusive. In particular, variations of the invention may be conceived comprising only a selection of features, described hereafter in isolation from the other described features, if this selection of features is sufficient to confer a technical advantage and / or to differentiate the invention from the prior art.
[0042] For the sake of clarity, the same elements are designated by the same references in the different figures.
[0043] Figure 1 is an exploded and simplified view of a prior art axial flux electric motor and has been presented previously.
[0044] Figure 2 depicts a stator body known from the prior art. It was presented earlier to highlight the difficulty of handling a stator body that is flexible after the annealing stage. Due to its lack of rigidity, the physical stability of the stator body becomes problematic. This results in a fragile stator body, whose teeth can easily detach, and in a circular shape that is difficult to control.
[0045] Figure 3 schematically illustrates an example of a positioning tool 100 for a stator body 12 according to the invention. The invention relates to a positioning tool for receiving a stator body 12 in order to give it a predefined geometry. The positioning tool 100 acts as an impression for the stator body 12.
[0046] The stator body is obtained from a sheet of steel which is wound upon itself. The steel sheet is pre-cut so that, after winding upon itself, the superposition of the layers formed by the steel sheet creates a succession of stator teeth 151 and notches 152. Such a stator body 12 is visible in Figure 2.
[0047] The stator body 12 has a circular shape, with center O. The stator body 12 must be glued onto a receiving plate 11. Once glued onto the receiving plate 11, it can be assembled within an axial flux machine.
[0048] Before being bonded to the plate 11, the stator body 12 undergoes an annealing process to give it the desired magnetic properties. After this annealing process, the stator body 12 is flexible and does not maintain a fixed shape. In other words, the stator body 12 is easily deformable. However, for reasons of magnetic flux equilibrium, it is imperative that the stator body 12 take on a well-defined circular shape, with a radius of the first radius rl. The stator body 12 comprises a plurality of stator teeth 151 distributed around its circumference and a plurality of notches 152, each formed between two adjacent stator teeth 151.
[0049] The positioning tool 100 of the invention is therefore designed to cooperate with the stator body 12 to shape it into a predefined geometric form. According to the invention, the positioning tool 100 comprises a plate 110 having an upper surface extending along a first plane PI. As illustrated in Figure 3, the plate 110 is circular. However, the invention is not limited to this, and the plate 110 could have a generally rectangular shape. The positioning tool comprises N positioning slats, where N is a natural number greater than 1, arranged on the upper surface 111 of the plate 110. In the example shown in Figure 3, N is equal to three. In other words, the positioning tool 100 comprises three positioning slats 120, 121, and 122.According to the invention, the positioning tool 100 comprises at least two positioning slats and can comprise up to a number equal to the number of notches 152 in the stator body that it is intended to accommodate.
[0050] Each positioning gib is positioned on a reference circle Cl with a radius equal to the first radius rl. Advantageously, but not necessarily, the reference circle Cl passes through the centers of the positioning gibs 120, 121, and 122. It is understood that the reference circle Cl could have a radius smaller or larger than the first radius rl. What is important for the purposes of this invention is the distance between the center of the plate 110 and the positioning gib, which must be equal to the inner radius of the stator body (namely, half the inner diameter dl).
[0051] Each positioning gib extends longitudinally, at least partially, along a reference radius rref of the reference circle Cl. A reference radius rref can be defined as a radius of the reference circle Cl on which a portion of the positioning gib is located. For example, the positioning gib 121 is located for half its length on a portion of the reference radius rrefl. The positioning gibs 120, 121, and 122 extend radially from the center of the plate 110 and are positioned at a predefined distance from the center.
[0052] This specific arrangement of the positioning pins 120, 121, and 122 creates a recess for the stator body 12, and more precisely for the notches 152 of the stator body 12. Indeed, N of the plurality of notches 152 in the stator body 12 are designed to be positioned on the N positioning pins in an assembled configuration. A notch positioned on a positioning pin means that two successive stator teeth frame the positioning pin. The two stator teeth are positioned on either side of the positioning pin.
[0053] This means that if the number of positioning pins is equal to the number of notches 152, each notch 152 is located on a positioning pin. However, the number of positioning pins may be less than the number of notches 152 on the stator body 12. In this case, one notch is located on positioning pin 120, one notch is located on positioning pin 121, and one notch is located on positioning pin 122. The remaining notches are not located on positioning pins. The space between two successive positioning pins on the plate 110 accommodates several notches and stator teeth.
[0054] The presence of at least two positioning lugs on the plate 110 allows for a very precise geometry to be defined for the stator body 12 intended to cooperate with the positioning tool 100. In addition, the stator body 12, when in position on the positioning tool 100, is blocked from rotation around an axis perpendicular to the first plane PI.
[0055] According to an optional feature of the invention, the positioning tool 100 comprises three positioning lugs 120, 121, 122. In other words, N is equal to 3. In addition to defining a very precise geometry for the stator body 12, the presence of three positioning lugs blocks the translation of the stator body 12 in a plane parallel to the first plane when it is placed on the positioning tool.
[0056] According to an optional feature of the invention, the reference radii rref form an angle of 120° between each pair. Since the positioning pins are partially arranged on a portion of a reference radius and extend in line with the associated reference radius, the three positioning pins 120, 121, 122 are distributed on the reference circle with equal angular spacing between two adjacent positioning pins. This geometric arrangement of the equidistant positioning pins 120, 121, 122 allows the stator body 12 to assume a circular shape. The circular shape of the stator body 12 is ensured by the complementary shapes of three notches in the stator body 12, which are designed to be positioned on the three positioning pins 120, 121, 122.
[0057] According to an optional feature of the invention, the plate 110 comprises at least N through-holes 1101. The through-holes 1101 allow the positioning pins to be fixed to the plate 110. Advantageously, the plate 110 comprises as many through-holes 1101 as there are positioning pins. Alternatively, the plate 110 may comprise more through-holes 1101 than positioning pins, in which case some through-holes 1101 are left free.
[0058] The through-holes 1101 are preferably arranged on the reference circle Cl. This arrangement of the through-holes, although not mandatory, allows the reference circle Cl to be used as a reference for measuring the distance from the center of the plate. However, the through-holes 1101 may be offset from the reference circle, provided that the positioning lugs are also offset in accordance with the offset of the through-holes from the reference circle.
[0059] Each positioning gib includes a through hole 1201. The through hole 1201 is advantageously located in the center of the positioning gib, that is, it passes through the positioning gib along its height hl and is situated at the intersection of the diagonals of its upper surface. A through hole 1201 in the positioning gib and a through opening 1101 in the plate 110 are positioned opposite each other to secure the positioning gib.
[0060] The positioning tool 100 includes N fastening devices. Therefore, it includes as many fastening devices as there are positioning pins. Each fastening device, for example a screw, is positioned through a through hole 1201 in the positioning pin and a through opening 1101 in the plate 110 so as to fix the positioning pin to the plate 110. The fastening device is flush with, or recessed from, the upper surface 125 of the positioning pin. In the example of the screw, this means that the screw head does not protrude from the upper surface 125 of the positioning pin so as not to damage the stator body when it is positioned on the positioning tool 100.
[0061] According to an optional feature of the invention, the plate 110 comprises at least N upper blind holes 1102, 1104 opening onto the upper surface 111 of the plate 110, preferably arranged on a reference radius rref.
[0062] Each positioning gib includes at least one lower blind hole 1202, 1203 leading to a lower surface of the positioning gib.
[0063] The positioning tool 100 comprises N pins, each arranged through a pair formed by an upper blind hole 1102, 1104 and a lower blind hole 1202, 1203. The cooperation of the pin with an upper blind hole and a lower blind hole ensures the correct orientation of the positioning gib with respect to the reference radius rref along which it must extend on the upper surface 111 of the plate 110.
[0064] For each positioning pin, the distance between a lower blind hole and the through-hole is identical to the distance between an upper blind hole and the through-hole in plate 110. Since the through-hole and the through-hole overlap, the lower and upper blind holes also overlap. The pin connects the positioning pin to the plate.
[0065] In addition to the fastening device, the placement of the pin at the level of the two blind holes, upper and lower, ensures the precise positioning of the positioning pin. Thus fixed to plate 110, the positioning pin is no longer free to rotate around the axis perpendicular to the foreground.
[0066] According to an optional feature of the invention, at least one positioning gib comprises, in cross-section along a plane perpendicular to the reference radius rref along which it extends, two lateral faces, each forming an acute angle A2 with respect to the normal to the first plane PI. In other words, the lateral faces of the positioning gib are inclined such that the width of the upper surface 125 of the positioning gib is less than the width of the lower surface of the positioning gib. Since two adjacent positioning gibs form a recess for receiving at least one stator tooth, the two lateral faces inclined at angle A2 form a flared recess as they extend away from the plate 110. Insertion of the stator tooth or teeth into the recess formed between two positioning gibs is facilitated.The guidance accuracy tightens as the stator tooth approaches the upper surface 111 of the plate 110.
[0067] According to an optional feature of the invention, the lateral faces of a positioning gib form a right angle A3 with the lower surface of the gib along a first height of the positioning gib, and the lateral faces are inclined along a second height of the positioning gib, between the first height of the positioning gib and the upper surface of the positioning gib. The volume of the recess between two positioning gibs located along the second height of the positioning gibs facilitates the insertion of the stator tooth or teeth between two positioning gibs. As the gib approaches the upper surface 111 of the plate 110, the guiding accuracy is greater due to the reduced inclination of the lateral faces of the positioning gibs. Finally, along the first height of the positioning gibs, the distance between two positioning gibs no longer varies with height.A retention zone for the stator tooth(s) is thus formed. This particular geometry of the positioning lugs facilitates the placement of the stator body 12 on the positioning tool 100 and ensures that the correct geometry of the stator body 12 is achieved.
[0068] Figure 4 schematically represents another example of a positioning tool 100 for a stator body according to the invention. The positioning tool shown in Figure 4 is identical to that shown in Figure 3. In this example, the positioning tool comprises, in addition to the three positioning lugs 120, 121, 122 detailed previously, several other, here by way of non-limiting example, nine additional positioning lugs 130, 131, 132, 133, 134, 135, 136, 137, 138. The additional positioning lugs have the same characteristics as the positioning lugs 120, 121, 122 presented previously. Alternatively, they may have a width less than the width 11 of the positioning lugs 120, 121, 122. By reducing the width of the additional positioning lugs, a wider housing between two successive positioning lugs is resulting.This facilitates the insertion of the stator teeth between the positioning slots.
[0069] According to an optional feature of the invention, the positioning tool 100 further includes a holding device 140 for holding the stator body 12 in position on the positioning tool 100 in the assembled configuration.
[0070] When the stator body 12 is positioned on the positioning tool, the positioning lugs of the positioning tool 100 are arranged in the notches of the stator body 12. The arrangement of the notches of the stator body 12 around the positioning lugs, that is, by wrapping the positioning lugs, restricts the rotational degree of freedom of the stator body about the axis perpendicular to the first plane. Similarly, the translational degrees of freedom of the stator body 12 in a plane parallel to the first plane PI are restricted.
[0071] As positioned on the positioning tool, the stator body is free to translate along an axis perpendicular to the foreground in the direction away from the upper surface of the positioning tool plate. Thanks to the retaining device, the stator body 12 becomes fixed to the positioning tool. The retaining device 140 can hold the stator body 12 in position on the positioning tool 100 in the assembled configuration when activated. It is thus understood that the retention of the stator body 12 on the positioning tool 100 is temporary. The stator body 12 can be detached from the positioning tool 100 when it no longer needs to be held in place.
[0072] Advantageously, the holding device is magnetic. The holding device comprises a plurality of magnets arranged on the periphery of the upper surface 111 of the positioning tool plate 110. Each magnet has an outer surface that is flush with the upper surface 111 of the plate 110. Advantageously, the magnets are arranged at least partially on the reference circle. Each magnet therefore opens onto the upper surface of the plate between two positioning prongs. In the assembled configuration, at least one stator tooth is pressed against one of the magnets. It is thus possible to hold the stator body in position against the positioning tool by the magnetic attraction exerted on the stator body by the magnets attached to the plate 111.
[0073] Figure 5 shows a positioned assembly 200 consisting of a stator body 12 and the positioning tool 100 according to the invention. The stator body 12 is in its assembled configuration, meaning that the notches of the stator body 12 are arranged on the positioning lugs of the positioning tool. For example, the notch 152 of the stator body 12 is arranged on the positioning lug 122. In the illustration in Figure 5, the positioning tool 100 comprises twelve positioning lugs (not all of which are visible). The positioning tool 100 includes three magnetic retaining devices 140. Three stator teeth are arranged on the three magnetic retaining devices 140. The other nine teeth are each positioned by contact with a positioning lug.The geometric shape of the stator body 12 is achieved primarily through the stator teeth, each of which fits between two positioning slots. For example, a stator tooth 151 is shown positioned between two positioning slots 122. The same principle applies to the other stator teeth and positioning slots, resulting in a circular stator body in its assembled configuration.
[0074] The invention also relates to a method for positioning such a stator body 12 on a positioning tool as described in this document. The method includes a step 300 of arranging N of the plurality of notches 152 of the stator body 12 onto the N positioning slots of the positioning tool 100. By arranging the notches 152 on the positioning slots, the stator teeth are positioned within the volume between two successive positioning slots. The lower surface 155 of the stator body 12 is then visible on top of the positioned assembly 200. The term "top" is to be understood as referring to the position of the positioning tool. Of course, if the positioned assembly 200 is inverted, the lower surface 155 of the stator body 12 would then be below the positioned assembly 200.It is in this latter case that the retaining device 140 becomes very important since it allows the stator body 12 not to fall under the effect of gravity.
[0075] Figure 6 schematically illustrates the steps of a method for bonding a stator body 12 to a receiving plate 11 according to the invention. The stator body 12 is intended to be bonded to the receiving plate 11, at a pre-defined location for its subsequent integration into an axial flux machine.
[0076] The process of bonding the stator body 12 to a receiving plate 11 includes a step 300 of positioning the stator body 12 on a positioning tool 100 according to the positioning process described above. This step is crucial for bonding the stator body 12 to the receiving plate 11. The positioning tool 100 serves as an impression for the stator body 12, which is geometrically configured relative to the positioning lugs of the tool. Through this step, the stator body 12 is extended according to the target geometry previously defined for the stator body 12.
[0077] The bonding process includes a step 310 of applying a layer of adhesive 16 to an upper surface 15 of the receiving plate 11. The upper surface 15 is the surface to which the stator body 12 will be bonded. More precisely, the bonding will be carried out between the upper surface 15 and the lower surface 155 of the stator body 12.
[0078] The bonding process includes a step 320 of bringing the lower surface 155 of the stator body 12 into contact with the upper surface 15 of the receiving plate 11, so as to form a pre-assembled plate 17. Since the upper surface 15 of the receiving plate 11 has been previously bonded, the lower surface 155 of the stator body 12 is then pressed against the upper surface 15. The contacting step 320 can be performed by translating the positioned assembly 200 towards the receiving plate, or conversely by translating the receiving plate towards the positioned assembly, or both. In the assembled configuration, the holding device 140 of the positioning tool 100 can be activated to hold the stator body in the assembled configuration. Thus, the direction of translation of the positioned assembly 200 can be adjusted, and the positioned assembly 200 can be reversed during step 320.
[0079] The bonding process includes a step 330 of convection curing of the pre-assembled tray 17 to obtain an assembled tray 18. During this step, the pre-assembled tray 17 from the contacting step 320 undergoes a curing phase to allow good adhesion of the glue between the receiving tray 11 and the positioned assembly 200.
[0080] Optionally, the bonding process may include a step 340 of cooling the assembled tray 18. After the curing step, it may be necessary to cool the assembled tray 18 before further handling. This cooling step also helps to enhance the mechanical and thermal properties of the assembled tray 18.
[0081] Finally, the bonding process includes a step 350 of removing the positioning tool 100 from the assembled plate 18. The stator body 12 is bonded to the receiving plate 11 in its target position and according to the required geometry. The positioning tool 100, which served as a support for the stator body 12, is removed from the assembled plate.
[0082] According to an optional feature of the invention, the bonding process includes, prior to step 310 of applying a layer of adhesive, a laser etching step 360 of the upper surface 15 of the receiving plate 11 and the lower surface 155 of the stator body 12. This step serves a dual purpose. On the one hand, it eliminates any surface irregularities that could affect the flatness of one or both surfaces. On the other hand, it ensures a smooth surface finish on both etched surfaces. This results in improved adhesion of the adhesive layer.
[0083] The invention effectively solves the problem it set for itself by proposing a tool for positioning the stator body on the tool plate. This tool initially ensures the stator body remains stable during handling and achieves the target shape by using positioning lugs to maintain the stator body's circular form. Subsequently, during bonding to the receiving plate, the invention guarantees that the stator body is bonded to the plate with the desired geometric shape and orientation.
[0084] Of course, the invention is not limited to the examples just described, and many modifications can be made to these examples without departing from the scope of the invention. In particular, the features of different embodiments of the invention can be combined to realize the invention, provided that these embodiments are not incompatible with each other.
Claims
1. CLAIMS:
1. Positioning tool (100) for a circular stator body (12) of a first radius (rl) comprising a plurality of stator teeth (151) distributed around its circumference and a plurality of notches (152), each formed between two adjacent stator teeth (151), the positioning tool (100) being characterized in that it comprises: A plate (110) having a top surface extending along a first plane (PD, N positioning slats (120, 121, 122, 130, 131,..., 138), N being a natural number greater than 1, arranged on the upper surface (111) of the plate (110), each slat being arranged on a reference circle (Cl) of radius equal to the first radius (rl) and extending longitudinally at least partially along a reference radius (rref) of the reference circle (Cl), N among the plurality of notches (152) of the stator body (12) being intended to be arranged on the N positioning slats in an assembled configuration.
2. Positioning tool (100) according to claim 1, wherein N is equal to 3.
3. Positioning tool (100) according to claim 2, wherein the reference radii (rref) form an angle (Al) of 120° between them.
4. Positioning tool (100) according to any one of the preceding claims, further comprising a retaining device (140) for holding the stator body (12) in position on the positioning tool (100) in the assembled configuration.
5. Positioning tool (100) according to any one of the preceding claims, wherein the plate (110) comprises at least N through openings (1101), preferably arranged on the reference circle (Cl), each positioning gib (120, 121, 122, 130, 131,..., 138) comprises a through orifice (1201), and the positioning tool (100) comprises N fixing devices, each being arranged through a through orifice (1201) and a through opening (1101) so as to fix the positioning gib to the plate (110).
6. Positioning tool (100) according to the preceding claim, wherein the plate (110) comprises at least N upper blind holes (1102, 1104) opening onto the upper surface (111) of the plate (110), preferably arranged on a reference radius (rref), each positioning gib (120, 121, 122, 130, 131,..., 138) comprising at least one lower blind hole (1202, 1203) opening onto a lower surface of the positioning gib, the positioning tool (100) comprising N pins, each being arranged through an upper blind hole (1102, 1104) and a lower blind hole (1202, 1203) so as to orient the positioning gibs along a reference radius (rref) on the upper surface (111) of the plate (110).
7. Positioning tool (100) according to any one of the preceding claims, in which at least one positioning gib comprises, in cross-section along a plane perpendicular to the reference radius (rref) along which it extends, two lateral faces each forming an acute angle (A2) with respect to the normal to the first plane (PI).
8. Positioned assembly (200) formed by a circular stator body (12) of a first radius (rl) comprising a plurality of stator teeth (151) distributed over its circumference and a plurality of notches (152), each formed between two adjacent stator teeth (151) and the positioning tool (100) according to any one of the preceding claims, N among the plurality of notches (152) of the stator body (12) being arranged on the N positioning lugs.
9. Method of positioning a stator body (12) on a positioning tool (100) according to any one of claims 1 to 7, the stator body (12) being circular of a first radius (rl) and comprising a plurality of stator teeth (151) distributed on its circumference and a plurality of notches (152), each formed between two adjacent stator teeth (151), the method comprising a step of arranging N among the plurality of notches (152) of the stator body (12) on the N positioning slots of the positioning tool.
10. Method for bonding a stator body (12) to a receiving plate (11), the stator body (12) being circular with a first radius (rl) and comprising a plurality of stator teeth (151) distributed around its circumference and a plurality of notches (152), each formed between two adjacent stator teeth (151), the method comprising the following steps: Positioning (300) of the stator body (12) on a positioning tool (100) according to the method of the preceding claim; Disposition (310) of a layer of glue (16) on an upper surface (15) of the receiving plate (11); Contacting (320) of a lower surface (155) of the stator body (12) against the upper surface (15) of the receiving plate (11) so as to form a pre-assembled plate (17); Convection cooking (330) of the pre-assembled tray (17) to obtain an assembled tray (18); Optionally, cooling (340) of the assembled tray (18); Disassembly (350) of the positioning tool (100) of the assembled plate (18).
11. Bonding method according to the preceding claim, comprising, prior to the step (310) of laying a layer of glue, a laser stripping step (360) of the upper surface (15) of the receiving plate (11) and of the lower surface (155) of the stator body (12).