Electric motor, stator for electric motor, and method for manufacturing same

Abstract

To provide a small-sized electric motor that is able to produce relatively high torque.SOLUTION: The present invention relates to a stator (3) for an electric motor (1), comprising a stator body (31) comprising a plurality of teeth extending between an outer part and an inner part of the stator body (31); and a plurality of coils configured to be respectively wound around the plurality of teeth between the outer part and the inner part of the stator body (31); where the stator (3) further comprises at least one first connection frame (7) disposed on the inner part of the stator body (31) and configured to provide electrical connections between the coils.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to the field of electric motors, in particular to electric motors mounted on electric bicycles. [Background technology]

[0002] Electrically assisted bicycles are becoming increasingly popular as they consume less energy, have a lower environmental impact, are inexpensive, and allow for easy mobility.

[0003] However, there are various constraints to using electric motors in e-bikes, especially the need for high torque and low rotational speed to provide effective assistance, which must simultaneously match the rider's pedaling rhythm.

[0004] Furthermore, the location of the electric motor on the bicycle is typically in the area of ​​the bottom bracket of the bicycle, which imposes size constraints in order to accommodate the electric motor without compromising other functions of the bicycle. Furthermore, the noise generated by the electric motor also needs to be limited. Summary of the Invention

[0005] Therefore, to at least partially address these limitations, the present invention aims to provide a compact electric motor capable of generating relatively high torque.

[0006] Therefore, an object of the present invention is to provide a stator for an electric motor having the following configuration: - a stator body including a plurality of teeth extending between an outer portion and an inner portion of the stator body; - a plurality of coils configured to be wound around the plurality of teeth between an outer portion and an inner portion of the stator body, respectively; Equipped with The stator is - further including at least one first connection frame disposed in an inner portion of the stator body and configured to provide an electrical connection between the coils. The first connecting frame is therefore arranged inside a cylinder, the periphery of which is defined by the coil.

[0007] According to one aspect of the present invention, the stator comprises: - in addition to the at least one first connection frame, at least one second connection frame arranged in an outer portion of the stator body and configured to provide an electrical connection between the coils; Further includes: The second connecting frame is therefore arranged outside a cylinder whose edge is defined by the coil.

[0008] According to another aspect of the invention, the stator teeth are separate, removable teeth.

[0009] According to another aspect of the invention, the coils are connected in a star configuration.

[0010] According to another aspect of the invention, the one or more first connection frames and / or second connection frames are configured to connect the coils using standard winding, which connects the coils of one phase in parallel with each other using full pitch winding.

[0011] According to another aspect of the invention, one or more of the first connection frame and / or the second connection frame are configured to connect several coils in series using fractional pitch winding.

[0012] According to another aspect of the invention, the coil is wound by starting from the inner part of the stator body: the winding starts from the end of the stator body that is intended to be directed towards the inside of the stator in the mounted state of the stator.

[0013] According to another aspect of the invention, the stator includes a first connection frame configured to connect the coils in a star or delta configuration and three second connection frames extending concentrically above an outer portion of the stator body for connecting the coils of one phase to each other, the second connection frames being separated from each other by non-conductive walls.

[0014] According to another aspect of the invention, the stator includes a second connection frame configured to connect the windings in a star or delta configuration, and three first connection frames extending concentrically above an inner portion of the stator body for connecting the coils of one phase to each other, the first connection frames being separated from each other by non-electrically conductive walls.

[0015] According to another aspect of the invention, the first connection frame is disposed on a module configured to be disposed on an inner portion of the stator body.

[0016] According to another aspect of the invention, the non-conductive wall is made of overmolded plastic.

[0017] In accordance with another aspect of the invention, an electrical insulation element is disposed on the stator body of the stator, the electrical insulation element including a winding retention pad.

[0018] According to another aspect of the invention, the retaining pad is a temporary pad configured to be removed upon positioning the at least one first connecting frame.

[0019] According to another aspect of the invention, an electrical insulation element is configured to receive one or more first and second connection frames.

[0020] The invention also relates to an electric motor including a stator such as above, the electric motor being a three-phase brushless motor.

[0021] According to another aspect of the invention, the electric motor includes 10 or 14 poles.

[0022] The present invention also relates to a method of manufacturing a stator including a stator body including a plurality of teeth extending between an outer portion and an inner portion of the stator body, the method including winding a plurality of coils around the plurality of teeth between the outer portion and the inner portion of the stator body, respectively, by starting winding from the inner portion of the stator. The method also includes disposing a first connection frame on the inner portion of the stator body, the first connection frame configured to provide an electrical connection between the coils.

[0023] Further characteristics and advantages of the invention will become more clearly apparent on reading the following description, given by way of non-limiting exemplary example, and the accompanying drawings, in which: [Brief description of the drawings]

[0024] [Figure 1] FIG. 1 is a schematic perspective view showing a part of an electric motor according to a first embodiment. [Diagram 2] FIG. 2 is a schematic perspective view of a stator body including a plurality of teeth around which coils are wound. [Diagram 3] FIG. 3 is a perspective view of a stator body including a plurality of separate teeth on which coils are wound. [Figure 4] FIG. 4 is an electrical diagram of a standard star winding for a three-phase electric motor containing 15 coils. [Diagram 5] FIG. 5 is an electrical diagram of a short-pitch star winding for a three-phase electric motor containing 18 coils. [Figure 6] FIG. 6 is a perspective view of a stator including a connection frame according to the first embodiment. [Figure 7] FIG. 7 is an exploded perspective view showing a portion of the stator of FIG. [Figure 8] FIG. 8 is an exploded perspective view showing a portion of the stator of FIG. [Figure 9] FIG. 9 is a schematic perspective view showing a part of an electric motor according to the second embodiment. [Figure 10] FIG. 10 is an exploded perspective view of a connection frame and coils of a stator according to the second embodiment. [Figure 11] FIG. 11 is a flowchart showing steps of a method for manufacturing a stator according to the first embodiment. [Figure 12] FIG. 12 is a flowchart showing steps of a method for manufacturing a stator according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] In the accompanying drawings, the same reference numbers are used for the same elements.

[0026] The following embodiments are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment or that a feature applies only to a single embodiment. Simple features of various embodiments can also be combined or interchanged to provide other embodiments.

[0027] In this specification, some elements or parameters may be numbered, e.g., a first element or a second element and a first parameter and a second parameter, or a first criterion and a second criterion, etc. In this case, this is simply a numbering scheme to distinguish between similar but non-identical elements or parameters or criteria. This numbering scheme does not imply a priority of one element, parameter or criterion over another, and such designations may be readily interchanged without departing from the scope of this specification. Furthermore, this numbering scheme does not imply a chronological order, e.g., for evaluating a particular criterion.

[0028] 1 shows a perspective view of part of an electric motor 1 including a stator 3 and a rotor 5. This electric motor 1 is, for example, a brushless electric motor, although the invention is not limited to this type of electric motor. Such an electric motor 1 is particularly suitable for being mounted on an electric bicycle, although the invention is not limited to this application.

[0029] As shown in Figure 2, the stator 3 includes a stator body 31 configured to accommodate a number of coils 33, fifteen coils in the example of Figure 2, although a different number of coils 33 can be used. The stator body 31 includes an outer cylindrical portion 31a from which extend a number of teeth 35, fifteen teeth in the example of Figure 1. The teeth 35 are oriented towards the center of the cylinder and have a T-shaped cross section configured to hold the windings that form the coils 33. The coils 33 are thus formed on each tooth 35 by winding a turn of the winding.

[0030] The teeth extend between an outer portion of the stator 3 defined by the outer cylindrical portion 31 a and an inner portion 31 b of the stator 3 defined by the inner ends of the teeth .

[0031] The windings forming the coils 33 typically include multiple turns extending adjacently between the inner and outer portions 31a, 31b of the stator 3. Additionally, multiple layers of turns may be stacked around the teeth 35.

[0032] The teeth 35 may be formed integrally with the outer cylindrical part 31a. According to an alternative embodiment, the teeth 35 are separate teeth that can be attached to and detached from the outer cylindrical part 31a. FIG. 3 shows an example of a stator 3 with separate teeth, in which the cylindrical part 31a includes a number of cutouts 310 that extend axially over the inside of the cylindrical part 31a. In the case of FIG. 3, the stator 3 includes 15 teeth 35, but stators 3 with other numbers of separate teeth can obviously be manufactured. The cutouts 310 have, for example, a T-shaped or U-shaped cross section. The teeth 35 then constitute fixed end pieces 350 that have a cross-sectional shape that fits into the cutouts 310. The fixed end pieces 350 are intended to be introduced into the cutouts 310 of the cylindrical part 31a by translational movement of the fixed end pieces 350 in the cutouts 310. The teeth 350 are fixed in place because the shapes of the fixed end pieces 350 and the cutouts 310 match. By using a stator 3 with separate teeth, the coils 33 can be wound around the teeth 35 before the teeth 35 are positioned in the cylindrical portion 31a. This reduces the space required between the coils 33 because the coils 33 can be placed closer together.

[0033] The stator 3 also includes a number of connection frames 7, 9 configured to provide electrical connections between the coils 33. The coils 33 can be connected using a variety of electrical connection configurations.

[0034] Figure 4 shows a first electrical configuration, where the stator 3 consists of 15 coils 33 of three phases, denoted u, v and w, which are connected in star configuration with standard windings, i.e. with several coils of one phase u, v and w arranged in parallel. Such a stator 3 can be used for an electric motor 1 with 10 poles.

[0035] Fig. 5 shows a second electrical configuration. Here, the stator 3 comprises 18 coils 33 of three phases, designated u, v and w. The coils 33 are also connected in star configuration as fractional pitch winding, i.e. as a series-arranged winding of several coils of one phase u, v and w. In this case, each phase comprises two branches of three coils 33 arranged in series, the two branches being arranged in parallel. Fractional winding allows a time lag between the active coils, which allows a smoother transition when the rotor poles 5 pass in front of the teeth 35 of the stator 3, and reduces the noise emitted by the electric motor 1. Such a stator 3 can be used, for example, for electric motors with 10 or 14 poles, but also with other numbers of poles.

[0036] Such a configuration having a large number of coils 33 and poles can provide high torque, while the size of the electric motor 1 can be limited because the coils are close to each other using separate teeth.

[0037] The present invention is not limited to the two winding configuration shown in Figures 4 and 5, other configurations may be used including different numbers of coils 33 connected in series and / or parallel, and in star or delta configurations.

[0038] Thus, the connection frames 7, 9 connected to the ends of the coils 33 are used to connect several coils 33 according to a selected electrical circuit diagram. These connection frames 7, 9 are placed on electrical insulation elements 14 (shown in FIG. 7) that are placed on the stator body 31. The stator body 31 is made, for example, of steel, and the electrical insulation elements 14 are made, for example, of plastic and can be overmolded onto the stator body 31.

[0039] 6-8 show a first embodiment according to the electrical diagrams of Fig. 1 and Fig. 3, in which the stator 3 includes a first connection frame 7 arranged in the inner part 31b of the stator body 31 and configured to connect the first ends of the coils 33 of each phase u, v, w to each other to form a star connection. The first connection frame 7 includes five parts, respectively indicated as 7a, 7b, 7c, 7d, 7e, each connecting the three coils 33 associated with the three phases u, v, w respectively. Preferably, the three coils 33 associated with the three phases u, v, w respectively may be arranged adjacent to each other on the stator body 31, as in Fig. 6.

[0040] The stator 3 also comprises a second connection frame 9 arranged on the outer part 31a of the stator body 31 and arranged to connect the second ends of the coils 33 according to the electrical diagram of FIG. 4 (parallel connection of the various coils 33 associated with the phases u, v, w). The second connection frame 9 is also arranged to allow electrical connection to the outside of the stator 3, in particular the supply of power to the various phases u, v, w, for example via additional connectors arranged on the second connection frame 9. In the example shown in FIG. 5, the stator 3 comprises three second connection frames 9, respectively indicated with 9a, 9b, 9c. The three second connection frames 9 are arranged concentrically on one side of the stator 3 around the coils 33. As shown more clearly in FIG. 7, the second connection frames 9 are separated from one another by non-conductive walls 11, also arranged concentrically with the second connection frames 9. These non-conductive walls 11 are for example made of plastic and can be overmolded on the stator body 31, in particular integrally formed with the electrical insulation element 14. In this embodiment, in order to avoid short circuits between the plurality of second connection frames 9, the height of the non-conductive wall 11 is higher than that of the second connection frame 9 and locally includes material recesses 110 in its part protruding from the second connection frame 9 to allow the connection of the coil 33 with the second connection frame 9. The material recesses 110 of the plurality of non-conductive walls 11 are arranged opposite each other and opposite the coils 33. The number of material recesses 110 corresponds, for example, to the number of coils 33, i.e., 15 in the example of FIG. 6. Furthermore, the second connection frame 9 includes a connector 13 configured to protrude axially outside the stator 3 and extend opposite the material recesses 110 of the non-conductive wall 11. The second end of the coil 33 is thus configured to extend radially through the material recess 110 to one connector of the second connection frame 9 arranged opposite the corresponding coil 33.

[0041] For this purpose, the first and second connection frames 7 and 9 are arranged adjacent to the stator body 31 on a first radial side of the stator body 31. Also, the axial height of the first and second connection frames 7 and 9 as well as the non-conductive wall 11 is limited as much as possible so as to limit the axial dimension of the stator 3.

[0042] Furthermore, by arranging the first connection frame 7 adjacent to the inner portion 31b of the stator body 31 and arranging the second connection frame 9 concentrically, the outer diameter of the stator 3 can be limited.

[0043] The axial and radial footprint of the stator 3 is therefore reduced compared to prior art electric motors of similar power.

[0044] Furthermore, as will be better explained throughout the remainder of the description, the coil 33 may be wound around the teeth 35 starting from the inner portion 31b side of the stator body 31. This makes it possible to limit the distance between the first connection frame 7 and the first end of the coil 33, and also to limit the footprint of the coil 33 and thus the stator 3.

[0045] 7 and 8, a retaining pad 15 may be arranged on the inner end of the tooth 35 (located on the side of the inner portion 31b of the stator body 31) to retain the first end of the wire of the coil 35, particularly when winding the turns to form the coil 35. The retaining pad 15 may be a temporary pad configured to be removed when connecting the first end of the coil 35 to the first connection frame 7. The retaining pad 15 may be arranged on the electrical insulation element 14, for example, and may be formed integrally with the electrical insulation element 14.

[0046] According to a second embodiment shown in figures 9 and 10, the stator 3 comprises first connection frames, respectively denoted 7a, 7b and 7c, arranged in the inner part 31b of the stator body 31 and arranged to connect the first ends of the coils 33 (parallel connection of the multiple coils 33 associated with the phases u, v and w) according to the electrical circuit diagram of figure 4. The first connection frame 7 is also arranged in particular to allow electrical connections towards the outside of the stator 3, for example via an additional connector 17, in order to supply power to the phases u, v and w. The first connection frames 7 are arranged, for example, in a similar manner to the second connection frame 9 described in the first embodiment, i.e. arranged concentrically with each other and separated by a non-conductive wall 11'. The non-conductive wall 11' also comprises material recesses 110 arranged opposite each other, the first connection frame 7 constituting a connector 13' extending axially opposite the material recess 110 so as to be connectable to the first ends of the coils 33 arranged opposite the material recess 110.

[0047] Furthermore, the first connection frame 7 and the non-conductive walls 11' can be arranged in a module 19 configured to be fixed to the stator body 31. The module 19 is, for example, made of plastic and includes radial tabs 190 at its edges configured to be arranged between the teeth 35 of the stator body 31 such that the module 19 is fixed to the stator body 31. The non-conductive walls 11' can be formed integrally with the module 19 and the first connection frame 7 is assembled to the module 19. The first connection frame 7 is, for example, arranged in slots provided between the non-conductive walls 11'.

[0048] The stator 3 also includes a second connection frame 9 (shown in FIG. 9 ) arranged on the outer part 31a of the stator body 31 and configured to connect the second ends of the coils 33 of the phases u, v, w to one another to form a star connection. The second connection frame 9 includes, for example, five parts, each connecting three coils 33 associated with the three phases u, v, w respectively. Alternatively, these connections can be made via one or more second connection frames 9 forming a complete ring to which some or all coils are connected depending on the desired electrical circuit diagram. Preferably, the three coils 33 associated with the three phases u, v, w respectively can be arranged adjacently on the stator body 31. The second connection frame 9 is arranged on an electrical insulation element 14, for example made of a plastic material, which can be overmolded on the stator body 31.

[0049] The one or more first connection frames 7 and the second connection frames 9 are made of a metal, such as for example aluminium, brass, copper or iron.

[0050] As in the first embodiment, the teeth 35 of the stator body 31 may be separate teeth, as shown in FIG.

[0051] According to a third embodiment, not shown, the stator 3 comprises only a first connection frame 7 arranged on the inner part 31b of the stator 3 and configured to provide all the electrical connections between the coils 33. The first connection frame 7 may be arranged on a module, such as the module 19 described above.

[0052] The invention also relates to an electric motor 1 including a stator 3 as described according to one of the above embodiments. The electric motor 1 also includes a rotor 5 (shown in figures 1 and 9) configured to be arranged inside the stator 3, i.e. in the center of the stator body 31 and the coils 33. The electric motor 1 is, for example, a three-phase brushless electric motor and includes, for example, 10 poles or 14 poles (in the case of an electric motor 1 having 15 coils), although other types of electric motors 1, in particular with a different number of poles, may also be used. The poles are, for example, generated by means of permanent magnets arranged on the rotor 5.

[0053] The present invention also relates to a method for manufacturing a stator 3 including a stator body 31 including a plurality of teeth 33 extending between an outer portion 31a and an inner portion 31b of the stator 3, for example, the stator 3 according to the first embodiment described above.

[0054] FIG. 11 is a flow chart showing steps of a method for manufacturing the stator 3 according to the first embodiment shown in FIGS. 1 and 6, in which the teeth 35 are formed integrally with the stator body 31. As shown in FIG.

[0055] The first step 101 concerns positioning the electrical insulation element 14 on the stator body 31. The electrical insulation element 14 is, for example, made of plastic and is overmolded onto the stator body 31. Furthermore, the electrical insulation element 14 includes a non-conductive wall 11.

[0056] A second step 102 concerns positioning the first connection frame 7 and the second connection frame 9 on the electrical insulation element 14. The first connection frame 7 is positioned on the outer part 31a of the stator body 31 and the second connection frame 9 is positioned on the inner part 31b of the stator body 31. The fixing frames are held by positive connection or stress on the electrical insulation element 14, whereby the connection frames can undergo plastic deformation by means of holding pads arranged on the electrical insulation element 14.

[0057] A third step 103 is an optional step that involves positioning a first end of the coil 33 on a retaining pad 15 configured to hold the end of the coil 33 in place when the coil is wound. The retaining pad 15 may be formed on the electrical insulation element 14.

[0058] The fourth step 104 concerns winding the coil 33 on the teeth 35 of the stator body 31. In this embodiment, the teeth 35 are formed integrally with the stator body 31, and the winding is generated starting from the inner part 31b of the stator body 31, as shown in Figures 7 and 8. The winding includes a number of coils extending from the inner part 31b to the outer part 31a of the stator body 31. By winding a new layer of turns on top of the previous layer of turns, multiple layers of turns can be formed, for example three layers of turns. The turns are held by edges formed by the ends of the teeth 35, which have a T-shaped cross section. In the case of three layers of turns, the winding ends at the outer part 31a of the stator body 31.

[0059] According to alternative embodiments, the windings can be made starting from the outer parts. Furthermore, the windings can include a number of layers of turns other than three. Preferably, the windings are made to make the most of the space available around the teeth 35 while still allowing the windings of adjacent coils 33 to be made. For example, the windings are made by a robot configured to wind turns around the teeth 35. The windings around the teeth 35 are produced one after the other, for example with the windings all being identical.

[0060] A fifth step 105 concerns the connection between the ends of the coil 33 on the one hand and the first connection frame 7 and on the other hand the second connection frame 9. The connection is made for example by welding or via connectors arranged on the connection frames 7, 9 and configured to hold the windings and provide an electrical connection between the windings and the connection frames 7, 9 or by any other means known to the person skilled in the art.

[0061] The sixth step 106 is an optional step and involves removing the retaining pad 15 used in step 103 if it is a temporary, removable pad.

[0062] The order of the steps may differ from that shown, for example, step 106 may be performed before step 105.

[0063] FIG. 12 is a flow chart illustrating steps of a method for manufacturing the above-described stator according to the second embodiment shown in FIGS.

[0064] The first step 201 concerns positioning the electrical insulation element 14 on the stator body 31. The electrical insulation element 14 is, for example, made of plastic and is overmolded onto the stator body 31. In this case, the electrical insulation element 14 extends over the outer portion 31a of the stator body 31.

[0065] The second step 202 concerns winding the coils on the teeth of the stator body 31. In this embodiment, the winding is made starting from the inner part of the stator. The winding comprises multiple coils extending between both ends of the teeth. Multiple layers of turns can be formed by winding a new layer of turns on top of the previous layer, for example three layers of turns can be formed. The turns are held by the edges formed by the ends of the teeth 35, which have a T-shaped cross section. If the turns are three layers, the winding ends at the inner part 31b of the stator body 31. Alternatively, the winding may end at another position.

[0066] Furthermore, the windings may include a number of layers of turns other than three. Preferably, the windings are made to maximize the use of the available space around the teeth 35. For example, the windings are made by a robot configured to wrap the turns around the teeth. The windings are all identical. Holding pads, which may or may not be removable, may be provided on the electrical insulation element 14 to hold the ends of the windings.

[0067] The third step 203 concerns positioning the second connecting frame 9 on the electrical insulation element 14 near the outer portion 31 a of the stator body 31 .

[0068] A fourth step 204 concerns positioning the module 19 including the first connection frame in the stator body 31. Positioning is completed by inserting the radial tabs 190 of the module 19 between the coils 33.

[0069] The fifth step 205 concerns the connection between the ends of the coil 33 and the connection frame 7, 9. The connection is made for example by welding, or via a connector placed on the connection frame 7, 9 and configured to hold the winding and provide an electrical connection between the connection frame 7, 9 and the winding, or by any other means known to the person skilled in the art.

[0070] The order of the steps may differ from that shown.

[0071] In any of the embodiments, the stator 3 may include separate teeth, as shown in Fig. 3. In this case, the coils 33 are first wound around the teeth 35, and then the teeth 35 are disposed on the stator body 31. The other steps may be similar to those described above.

[0072] Thus, by arranging the connection frames on both the inner part 31a and the outer part 31b of the stator body 31 and thus the stator 3, an electric motor 1 that is compact in the axial and radial directions can be obtained, which makes it particularly easy to integrate into electric bicycles. Furthermore, the manufacture of such an electric motor remains simple, allowing large-scale production.

Claims

1. A stator (3) for an electric motor (1), comprising: - a stator body (31) including a plurality of teeth (35) extending between an outer portion (31a) and an inner portion (31b) of the stator body (31); - a plurality of coils (33) configured to be wound around the plurality of teeth (35) between the outer portion (31a) and the inner portion (31b) of the stator body (31), respectively; Equipped with The stator (3) is - a plurality of first connection frames (7) arranged on the inner portion (31b) of said stator body (31) and configured to provide electrical connections between said coils (33); - non-conductive walls (11') separating said first connection frames (7) from each other; Further comprising: The height of the non-conductive wall (11') is greater than that of the first connection frame (7); the non-conductive wall (11') locally comprises a material recess (110) in the part protruding from the first connection frame (7); The first connection frame (7) includes a connector (13') extending opposite the material recess (110) so as to be connectable to an end of the coil (33) arranged opposite the material recess (110).

2. A stator (3) for an electric motor (1), comprising: - a stator body (31) including a plurality of teeth (35) extending between an outer portion (31a) and an inner portion (31b) of the stator body (31); - a plurality of coils (33) configured to be wound around the plurality of teeth (35) between the outer portion (31a) and the inner portion (31b) of the stator body (31), respectively; Equipped with The stator (3) is - at least one first connection frame (7) arranged on the inner part (31b) of said stator body (31) and configured to provide an electrical connection between said coils (33); - a plurality of second connection frames (9) arranged on the outer portion (31a) of said stator body (31) and configured to provide electrical connections between said coils (33); - a non-conductive wall (11) separating said second connection frames (9) from each other; Further comprising: The height of the non-conductive wall (11) is greater than that of the second connection frame (9); the non-conductive wall (11) locally comprises a material recess in the part protruding from the second connection frame (9); The second connection frame (9) includes a connector (13) extending opposite the material recess (110) so as to be connectable to an end of a coil (33) arranged opposite the material recess (110).

3. The stator (3) is in addition to said at least one first connection frame (7), at least one second connection frame (9) arranged on the outer part (31a) of said stator body (31) and configured to provide an electrical connection between said coils (33); The stator of claim 1 further comprising:

4. 3. The stator (3) according to claim 1 or 2, wherein the teeth (35) of the stator (3) are separate, detachable teeth.

5. at least one of the first connection frame (7) and / or the second connection frame (9) is configured to connect the coils (33) using standard windings, 3. A stator (3) according to claim 1 or 2, wherein the coils (33) of one phase (u, v, w) are connected in parallel with one another using full pitch windings.

6. 3. A stator (3) according to claim 1 or 2, wherein at least one of the first connection frame (7) and / or the second connection frame (9) is configured to connect several coils (33) in series using short-pitch windings.

7. 3. The stator (3) according to claim 1 or 2, wherein the coil (33) is wound by starting winding from an inner portion (31b) of the stator body (31).

8. a first connection frame (7) configured to connect the coils (33) as a star or delta connection, and three second connection frames (9) extending concentrically on an outer portion (31a) of the stator body (31) for connecting the coils (33) of one phase (u, v, w) to each other. A stator (3) according to claim 2.

9. 2. A stator (3) according to claim 1, comprising a second connection frame (9) configured to connect the coils as a star or delta connection, and three first connection frames (7) extending concentrically on an inner part (31b) of the stator body (31) for connecting the coils (33) of one phase (u, v, w) to each other.

10. 10. The stator (3) according to claim 9, wherein the first connection frame (7) is arranged on a module (19) adapted to be placed on an inner part (31b) of the stator body (31).

11. An electrical insulation element (14) is disposed on the stator body (31) of the stator (3); 3. A stator (3) according to claim 1 or 2, characterized in that the electrical insulation elements (14) comprise winding retaining pads (15).

12. The stator (3), - in addition to said at least one first connection frame (7), at least one second connection frame (9) arranged on the outer part (31a) of said stator body (31) and configured to provide an electrical connection between said coils (33). Including, 12. The stator (3) according to claim 11, wherein the electrical insulation element (14) is configured to accommodate at least one of the first connection frame (7) and the second connection frame (9).

13. An electric motor (1) comprising a stator (3) according to claim 1 or 2, The electric motor (1) is a three-phase brushless motor.

14. A method for manufacturing a stator (3) according to claim 1 or 2, comprising the step (104) of winding a plurality of coils (33) around a plurality of teeth (35) between an outer portion (31a) and an inner portion (31b) of the stator body (31), The winding step (104) is carried out starting from the inner part (31b) of the stator (3), The method further comprises the step (102) of positioning a first connection frame (7) on the inner portion (31b) of the stator body (31), The method of claim 1, wherein the first connection frame (7) is configured to provide an electrical connection between the coils (33).

15. The method further comprises the step of arranging an electrical insulation element (14) including a winding retention pad (15) on the stator body (31) of the stator (3); 15. The method according to claim 14, wherein in the step of positioning (102) the first connection frame (7), the windings holding pad (15) is removed.

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