FR3012924A1 - ELECTRIC MACHINE TOOTH INSULATION MASK AND STATOR / ROTOR OF SUCH AN ELECTRIC MACHINE - Google Patents

Abstract

Mask for isolating a tooth (12) of an electric machine, especially an electric motor or a generator for electrically insulating the notch (14) of the stator (10) and / or the rotor of the machine . The winding around the insulation mask (30) of the tooth (12) is made with a winding wire or winding exerting a linear mechanical load on the tooth.

Description

FIELD OF THE INVENTION The subject of the invention is an electrical machine tooth insulation mask, in particular an electric motor or a generator for electrically isolating the notch of the stator or rotor of the machine. The subject of the invention is also a stator or rotor of an electric machine as well as an electric machine, in particular an electric motor or a generator with such a stator or rotor. State of the art Usually, a tooth insulation mask which can also be called a "notch isolation mask" allows electrical isolation of the teeth or notches of a stator or rotor of an electric machine . The thickness of the tooth insulation mask is constant in the notches of the stator or rotor all along the length in both the axial direction and the peripheral direction of the machine. The teeth isolation masks receive the winding of the electrical machine ensuring its operation or the teeth insulation masks receive a respective winding. If the wire, for example the copper wire, of the winding is wound with a wire pull, we have air gaps in the corresponding notch of the stator or the rotor between the copper winding and the mask of the wire. isolation of teeth and between the tooth insulation mask and for example the lamella package constituting the stator or the rotor, directly along these teeth. These gaps or air gaps considerably reduce the thermal conductivity between the winding and the lamella bundle at the flanks of the teeth. In addition, this path that is only weakly thermally conductive deteriorates the heat removal characteristics of the winding which results in an electric machine with low torque density. Object of the Invention The object of the present invention is to improve the tooth insulation mask of an electric machine. The invention also aims to improve the stator and / or the rotor of an electric machine. For the same dimensions of the machine or its stator and / or the rotor and the density of the torque should be improved with respect to that of the state of the art. In particular, if it is necessary to improve the thermal conductivity between the windings and the teeth of the machine. In addition, it is necessary to improve the efficiency of the electric machine. DESCRIPTION AND ADVANTAGES OF THE INVENTION For this purpose, the subject of the invention is a tooth insulation mask of the type defined above, characterized in that the winding around the tooth insulation mask is made with a winding wire or winding exerting a linear mechanical load and / or on the tooth. According to another characteristic of the invention, the linear and / or surface loading is exerted on a blank of the tooth extending in the rising direction, the tooth flank extends in the rising direction and in the longitudinal direction and / or in the upward direction and in the transverse direction of the tooth, a wall of the tooth isolation mask is at least partly arched, arc-shaped, circular arc-shaped, or in the form of an ellipse segment, the tooth insulation mask comprises a tooth of the stator or rotor of the machine, and the tooth insulation mask is made of plastic, an insulating varnish, an insulating resin, silicone or rubber. The invention also relates to a stator or rotor of an electric machine of the type defined above characterized in that a wall of the insulation mask is made thicker in the middle segment in the axial direction and / or in the direction stator or rotor device only in the corner segment of the wall. According to another characteristic of the invention, the maximum thickness of the wall is greater by a coefficient of approximately (1.5, 1.75, 2.0: 2.25, 2.5, 2.75; 3.0, 4.0, ± 5-10 °) / 0) relative to the minimum thickness of the wall. According to another characteristic of the invention, the tooth insulation mask in the cutting plane has a substantially symmetrical shape with respect to a point for the center of the tooth, in the cutting plane, the insulation mask of The teeth are essentially cylindrical in shape with respect to the axis of rotation of the tooth, the stator or rotor is a segmented and / or rolled stator or rotor, the stator or rotor is a stator or rotor in In one piece or in one piece, the tooth insulation mask is made of plastic, an Iso-Varnish, insulation resin, silicone or rubber. Finally, the subject of the invention is an electric machine, in particular an electric motor or a generator with a stator or rotor according to the invention, such as those defined above. The tooth insulation mask according to the invention is made so that a winding around an insulation mask provided on a tooth allows the winding wire or the winding mechanical load, ensure a linear and / or surface charge on the tooth. This linear load and / or surface is exerted in the rising direction of the side of the tooth and on the lateral flanks in the upward and longitudinal direction and / or the rising direction and the transverse direction of the tooth. The wall of the insulation mask according to the invention is at least partly curved, arc-shaped or circular arc segment or ellipse segment. According to developments of the invention, the tooth insulation mask is provided for a tooth of a stator or a machine rotor. The tooth is part of the stator or rotor; the tooth may be a stator or rotor segment. In these cases, the stator or rotor segment is part of the tooth insulation mask and vice versa. The tooth insulation mask itself is made of plastic, insulating resin, insulating varnish, silicone or rubber. The tooth insulation mask is made as an insulation mask for stator or rotor teeth. The stator or rotor according to the invention comprises at least one tooth and the insulation mask provided on the tooth insures the insulation of the tooth or notch of the stator or rotor. According to the invention, the wall of the tooth insulation mask is thicker in its median segment in the axial direction and / or the peripheral direction of the stator or rotor than in the end segment or corners of the wall. The stator or rotor may be a stator or rotor segment and / or laminated. One can also have a stator or rotor in one piece or another type of stator or rotor. The electric machine according to the invention comprises a tooth insulation mask and / or a stator or rotor as defined above. According to a development of the invention, the evolution of the thickness of the wall of the tooth insulation mask in the middle segment is such that a winding or a wire of the winding provided on the tooth insulation mask exerts a mechanical force directed inwards on the tooth insulation mask and / or the tooth. The thickness of the wall of the medial segment concerned first increases from the longitudinal end of the medial segment in the longitudinal direction of this segment to decrease again towards the other end of this segment (evolution of the 'thickness). Preferably, the thickness of the wall of the median segment concerned increases first of all with a continuous mason and then decreases continuously independently of the slot provided in the middle segment and this over the entire extension of the median segment ( evolution of the thickness). Preferably, the radius of curvature of the outer boundary of the wall is either constant or the radius of curvature is substantially at most at one end of the length or at both ends of the length of the median segment concerned and is practically at a minimum in a region or an intermediate place. The region or location having the maximum radius of curvature or the region or location of the thickest wall is preferably midway between the longitudinal ends of the middle segment. Preferably, the section of the wall in a sectional plane has a single axis of symmetry. According to preferred developments of the invention, the two walls which are substantially parallel in the axial direction for the same tooth insulation mask have a thicker diameter or a larger radius compared to that of a corner segment ( evolution of the thickness). This applies analogously, alternatively or in addition to the two walls which are substantially parallel in the peripheral direction.

In the cutting plane of the tooth preferably in the axial direction and in the peripheral direction of the stator or rotor or preferably in the longitudinal and transverse direction of the tooth independently of the slot provided in the tooth insulation mask, the middle segment is at least partly curved, arc-shaped, arc-shaped segments or elliptical arc segments. Thus, the inner side of the middle segment is adapted to the tooth. In addition, the inner side of the wall is preferably straight or in the form of a straight surface. The maximum thickness of the wall in the middle segment is, for example, from about 1.25 to about four times greater than the minimum wall thickness in the corner segment. According to the invention, the insulation mask is substantially symmetrical with respect to a point in the plane of section, vis-à-vis the center of the tooth. In addition, the tooth insulation mask in the cutting plane is substantially symmetrical-plane with respect to the axis of rotation (surface) of the tooth. In embodiments of the invention, the tooth insulation mask is an insulation mask in one or more parts, in particular in two parts. In the case of a multi-part insulation mask, it is a preferential manner of essentially identical mask parts. The teeth insulation mask is made of a plastic material, an insulating varnish, an insulating resin or silicone or rubber. According to the invention, the thickness of the tooth insulation masks increases on the teeth or in the notches of the stator or rotator between an end region, axial, to the middle of the pole teeth or notches by This allows for example to the copper wires of the winding, when it is wound with a pull of the wire around the insulating mask the tooth, along the entire axial length of the electric machine, by exerting a mechanical force directed towards the tooth insulation mask. This reduces the air gaps or parasitic air gaps between the copper winding and the tooth insulation mask as well as between the tooth insulation mask and for example a package of lamellae forming the stator and / or the rotor.

The reduction of parasitic air gaps increases the thermal conductivity between the winding and the stator or the rotor, for example with respect to the packets of lamellae which constitute them. This reduces the temperature of the winding for a predefined loss in the copper which increases the reliability of the winding and the tooth insulation mask. In addition, according to the invention, one can have greater losses in the copper for a given maximum temperature of the winding which increases the cutting density of the electric machine. In other words, for the same dimensions of the machine or the stator and / or the rotor, the torque density is improved compared with those of the state of the art. Drawings The present invention will be described in more detail below with the aid of an electrical machine tooth insulation mask, in particular an electric motor or generator, and a stator or rotor of such machine according to the invention. invention, shown in the accompanying drawings in which the same elements bear the same references. Thus: FIG. 1 is a central radial section of an electric machine stator according to the state of the art; FIG. 2 is a peripheral section of a stator tooth of FIG. 1 with an insulation mask; of the tooth according to the state of the art, this mask carrying a winding, - Figure 3 is a detail view of Figure 2 explaining the parasitic air gaps between the tooth and the tooth insulation mask as well as between the tooth insulation mask and the winding, - Figure 4 is a view similar to that of Figure 2 in the case of a tooth insulation mask according to the invention between the tooth and Figure 5 is a representation similar to that of Figure 3 showing the parasitic air gaps reduced or significantly minimized between the tooth insulation mask according to the invention of Figure 4 and the tooth as well as winding.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION FIG. 1 shows a section of an ordinary insulating and winding stator 10 of an electric machine 1 with single tooth windings 20. The stator 10 can be segmented and for the realization of the complete stator 10, each segment of teeth is electrically isolated by segment prior to mounting to the other tooth segments and receives a winding 20. The stator 10 can be realized under the form of a single pack of lamellae (see lamellae 100 or plate lamellae 100 of FIGS. 3 and 5); the windings 20 are made with a winding needle on the teeth 12 or pole teeth 12 of the stator 10 teeth electrically insulated by an insulating mask 30; the windings are made in the notches 14 of the stator 10. The tooth insulation mask 30 is often also called "notch isolation mask 30". The structure of the different tooth insulation masks is dependent, for example, on the stator structures described above. In the case of a segmented stator, there may be two half-tooth insulation masks 32 for each tooth 12 circumferentially surrounding the tooth in the radial direction R; in the case of a one-piece stator 10, the two half-masks of tooth insulation cover all of the stator 10 with the exception of the outer surface and the bore. Figure 2 shows a section of a tooth 12 which preferably a rolled tooth 12 whose winding 20 and these two insulating half-masks 32 are visible. The half-tooth insulating masks 32 are applied axially on each tooth 12, in particular fitted and in the installed state, there remains a small slot 35 between two corresponding half-tooth insulating masks 32 to take account of the tolerance. axial of the laminated tooth 12 and half-masks of tooth insulation 32.

When the winding 20 or the coil 20 is made with a predefined mechanical force, that is to say a predefined tension around the respective insulated tooth 12, slightly extends for example the copper wire 22 of the winding 20 in its elastic range. This results in an inwardly directed mechanical force acting on the four corners of the insulated tooth 12. Figure 2 explains this by four arrows. This inwardly facing force closes at the corners, the parasitic air gaps that may exist, occasionally between the copper wire 22 and the tooth insulation mask 30 as well as between the insulation mask 30 and the rolled tooth 12 (see Fig. 3). Closing these air gaps improves the thermal conductivity at these locations between the winding 20 and the tooth 12. But along the axial sides of the teeth 12 there are nevertheless air gaps 40, parasitic in the region of the air. 14 because in these regions the copper wire 22 can not exert inwardly thrust on the insulation mask 30 or tensile force 12 to close the air gaps 40. The copper wire 22 thus simply bypassing the tooth insulation mask 30. This significantly decreases the thermal conductivity along the axial sides of relatively large surfaces between the winding 20 and the tooth 12. FIG. 3 shows the detail of FIG. Highlighting the air gaps 40. These poor thermal conductor paths limit the heat dissipation of the winding 20, which limits the intensity of the current in the winding 20 to respect the maximum temperature. In turn, this limits the torque density of the electric machine 1. FIG. 4 shows a section in the axial direction A and in the peripheral direction U of the stator 10 of a tooth 12 or polar tooth 12 according to the invention. the radial direction R is perpendicular to the axial direction A and the peripheral direction U. The invention consists in increasing the thickness of the wall 34 of the tooth insulation mask 30 starting from a corner region 344, axial or axial wedge segment 344 (wedge segment or wedge region 344) to axial center region 342 or axial middle segment 342 of tooth 12 of notch 14 or wall 34. Correspondingly to axial direction A , at the peripheral direction U and the radial direction R, there is here a longitudinal direction A, a rising direction R and a transverse direction U of the tooth concerned 12. In the drawing, only an embodiment of invention, but it is possible to apply the invention to other embodiments. Thus it is for example possible to apply the invention to a rotor. FIG. 4 shows the wall thickness 34 which globally increases by approximately a coefficient equal to 2 following a continuous variation; the coefficient of constant increase can nevertheless be any and is preferably between about 1.5 and about 3. The design of the tooth insulation mask 30 according to the invention makes it possible to wind the copper wire 22 of the winding on the isolated tooth 12 to exert a mechanical force directed towards the inside of the tooth as a linear or surface charge q on the tooth insulation mask 30 and thus on the tooth 12. Preferably, this q linear or q surface charge q on the tooth insulation mask 30 can be exerted over the entire axial length of the slot 14 as indicated by the arrows in Figure 4.

This linear q or polygonal load q reduces the gap or gap-gap 40 between the winding 20 and the tooth insulation mask 30 as well as between the tooth insulation mask 30 and the stator teeth 12, for example laminate (see FIG. 5) which increases the thermal conductivity between the winding 20 and the stator lamellar pack 10. This makes it possible either to reduce the temperature of the winding 20 for some loss in the copper, which lengthens the life of the winding 20 and / or the tooth insulation mask or for the same loss in the copper can increase the maximum temperature preset winding 20 so as to increase the torque density of the machine electric. The invention is particularly suitable for electrical machines 1 having relatively short axial dimensions because with respect to a predefined increase the thickness of the tooth insulation mask 30 starting from an axial wedge segment 342 (with a minimum diameter from the wall 34 to the medial segment 342 (up to the maximum diameter of the wall 34) the angle α increases for a decrease in the axial length of the stator 10. This solution is advantageous because a larger angle α increases the linear load q or surface charge q generated by the winding wire 22 under mechanical tension and which is not necessarily made of copper, this tension being exerted on the tooth insulation mask 30 to close the air gaps 40. FIG. 5 shows a detail of FIG. 4 in which the parasite gap 40, according to the state of the art, is completely closed again (ideal situation).

The invention will be compared with the state of the art, hereinafter. Although the thickness of a tooth insulation or notch insulation is increased by the thicker middle segment 342 of the tooth insulation mask 30, the thermal advantages of a smaller air-parasitic gap 40 are obvious. In the ideal case, the thermal resistance to the application of the invention is reduced by about 74%. If the air gaps 40 are reduced by the invention by only 50%, the thermal resistance is nevertheless reduced by about 33%. In addition, the use of the invention slightly increases the length of the winding wire 22 so that losses in the copper will be slightly increased. However, it can be assumed that increasing the thermal conductivity between the winding 20 and the stator lamellar pack 10 more than significantly offsets this effect. The thermal resistance associated with the thermal interfaces between the winding 20 and the stator lamella packet 10 in the notches 14 of the stator 10 are calculated according to the state of the art (see FIG. 3) as follows: Lairox-m) Lm 1 [Lairr'-trt) Lm L (ws) k, h ,. The thermal resistance related to the thermal conductivity between the winding 20 and the stator lamellae pack 10 in grooves 14 of the stator 10 according to the invention (see FIG. calculate in detail as follows: R - - = - [- 1 (v`-s) kmA A k m- where: - L is a length, - A is a surface of the thermal path concerned, - K is the conductivity of the material concerned, - M is an index for the tooth insulation mask 30 (plastic material), - S is the index of the lamellar package of the stator 10, - W is the index of the winding 20 and air as an index of the air gap 40. Using the following properties of the material and dimensions for a temperature of about 27 ° C: kair = 0.0262 W / m / ° C, km = 0.25 W / m / ° C, Lair (wm) = 0.1 mm, Lair (ms) = 0.1 mm, Lm (SdT) = 0.4 mm, Lm (invention) = 0.6 mm (average thickness along the axial length). A = 200 mm 2 (tooth height: 10 mm, axial length of the tooth 20 mm), then the thermal resistances are obtained between the winding 20 and the lamellar pack of the stator 10 in the following boxes 14: of the technique (with parasitic air gaps 40 up to 46 ° C / W = 100%), according to the invention (in the ideal case no air gap 40) 12 ° C / W is obtained (= 26%), and according to the invention, 50% reduction of the air gaps 40 one reaches up to 31 ° C / W (= 67%). This means that the thermal resistance according to the invention is in the ideal case only 26% of the thermal resistance according to the state of the art. The increase in thickness according to the invention for the wall 34 of the middle segment 342 can be similarly applied also for one or both walls 34 in the peripheral direction U of the tooth insulation mask. 30. The tooth insulation mask 30 itself may be in one piece or in several parts. In the case of a multi-part mask, in particular a two-part tooth insulation mask 30, this mask preferably comprises identical mask insulating parts 32 or insulating half-masks 32 (see FIG. Figure 4). Preferably, the tooth insulation mask 30 is made of plastic, insulating varnish, insulating resin, silicone or rubber. The medial segment 342 or medial region 342 of the wall 34 of the tooth insulation mask 30 represents any segment of the wall 34 in the axial direction A (longitudinal direction of a tooth 12) or in the direction U peripheral (transverse direction of a tooth 12) which does not include the end segment or wedge region 344 of the tooth insulation mask 30. This is explained in Figure 4 by braces 342 that can be also lengthen or shorten to each free end in the axial direction A or in the peripheral direction U (double arrow). Preferably, the median segment 342 is disposed symmetrically with respect to the outer dimension of the tooth 12 retained. In addition and preferentially, the medial segment 342 has its thickest wall diameter, or the largest wall radius substantially mid-way between these two longitudinal ends. The invention relates to the design of the insulating masses of stator and rotor teeth. The thickness of a tooth insulation mask for a tooth or notch increases at least one axial and / or peripheral end segment or wedge segment to the axial and / or peripheral medial segment in a continuous manner. . Thus, when the winding wire is wound in the notches with a corresponding traction around the teeth, it exerts practically throughout the axial and / or peripheral length an inwardly directed mechanical force acting on the mask. tooth insulation which decreases the air-parasitic gap between the winding and the tooth insulation mask as well as between the tooth insulation mask and the tooth of the stator or rotor or the respective notch . Reducing this air gap improves the thermal conductivity between the winding and the stator or rotor. The invention can be applied to any electrical machine wound around teeth of the machine that is to say the stator and / or the rotor of the machine. It is for example an electric motor or a generator, in particular machines with permanent excitation (pm) with or without a brush, the motor CE, of variable inductance motor (SRM) of magnetic flux switching machines. or others, particularly for a vehicle (eg for driving, actuating or a power steering motor) or power tools etc.

10 NOMENCLATURE OF KEY ELEMENTS 10 Stator 12 Tooth / Polygonal tooth 14 Notch 20 Tooth wound 22 Copper wire 30 Tooth isolation mask 32 Tooth isolation half mask 35 Notch 40 Air gap 100 Lamella / Lamella in Sheet 342 Middle segment 344 Corner segment A Axial direction M Rising direction R U-direction U Peripheral direction / Transverse direction20

Claims (2)

CLAIMS1) Mask isolation of a tooth (12) of an electric machine (1), in particular an electric motor (1) or a generator (1) for electrically isolating the notch (14) of the stator (10) and / or rotor of the machine (1), insulating mask (30) characterized in that the winding (20) around the insulating mask (30) of the tooth (12) is made with a winding wire (22) or a winding (20) exerting a linear mechanical load (q) and / or (q) on the tooth (12). 2 °) tooth isolation mask according to claim 1, characterized in that the linear load (q) and / or surface (q) is exerted on a blank (13) of the tooth (12) extending in the rising direction (R), - the tooth flank (13) extends in the upward direction (R) and in the longitudinal direction (A) and / or in the upward direction (R) and in the transverse direction (U) of the tooth (12), - a wall (34) of the tooth insulation mask (30) is at least partly curved, arc-shaped, circular arc-shaped, or in the form of an ellipse segment, - the tooth insulation mask (30) has a tooth (12) of the stator (10) or rotor of the machine (1), and - the tooth insulation mask ( 30) is made of plastic, an insulating varnish, an insulating resin, silicone or rubber 3) Stator or rotor of an electric machine (1), in particular an electric motor (1) or a generator (1) comprising: - a tooth ( 12) and an isola mask tion (30) according to one of claims 1 and 2 provided on the tooth (12) for electrically insulating the notch (14) of the stator (10) or rotor, characterized in that a wall (34) of the mask of insulation (30) is made thicker in the middle segment (342) in the axial direction (A) and / or in the circumferential direction (U) of the stator (10) or the rotor than in the corner segment (344) of the wall (34) .4 °) Stator or rotor according to claim 3, characterized in that the evolution of the thickness of the wall (34) in the middle segment (342) is such that the mechanical force exerted on the tooth insulation mask (30) by the winding (20) is exerted on the tooth insulation mask (30) and / or on the tooth (12). Stator or rotor according to claim 3, characterized in that the thickness of the wall (34) of the middle segment (342), starting from a longitudinal end of the middle segment (342) first increases in the direction at the other longitudinal end of this medial segment (342) to decrease again and preferably the thickness of the wall (34) of the middle segment (342) independently of the slot (35) provided in this middle segment (342) , increases in particular continuously and then decreases again over the entire extension of this median segment (342). Stator or rotor according to Claim 3, characterized in that the two walls (34) in the axial direction (A) of a single tooth-insulating mask (30) have a thicker diameter or more radius. large by comparison with a wedge segment (344) and / or both walls (34) in the circumferential direction (U) of a separate tooth insulation mask (30) have, in comparison with a wedge segment ( 344), a thicker diameter or a larger radius. 7 °) Stator or rotor according to claim 3, characterized in that in a cutting plane of the tooth (13), independently of the slot (35) provided in the tooth insulation mask (30), the middle segment (342) has an at least partially domed shape, an arc segment shape, a circular arc shape or an ellipse segment shape and the inner side of the middle segment (342) is particularly adapted to the tooth ( 13). Stator or rotor according to claim 3, characterized in that the maximum thickness of the wall (34) is greater by a coefficient of approximately (1.5; 1.75; 2.0: 2.25 2.5, 2.75, 3.0, 4.0, ± 5-10%) relative to the minimum thickness of the wall (34). 9 °) Stator or rotor according to claim 3, characterized in that the tooth insulation mask (30) in the cutting plane has a shape substantially symmetrical with respect to a point for the center of the tooth (12), in the cutting plane, the tooth insulating mask (30) has a substantially planar cylindrical shape with respect to the axis of rotation of the tooth (12), - the stator (10) or the rotor is a stator (10) or a segmented and / or laminated rotor, - the stator (10) or the rotor is a stator (10) or a one-piece or integral rotor, - the tooth insulation mask (30) is in plastic material, an insulating varnish, an insulating resin, silicone or rubber, and / or - the tooth insulation mask (30) is produced according to claims 1 or 2. 10 °) Electrical machine including electric motor (1) or generator (1), characterized in that it comprises a tooth insulation mask (30) according to claims 1 or 2 and / or a stator (10) or a rotor according to one of claims 3 to 9.