Electric motor

Abstract

electric motor comprising a stator composed of circumferentially arranged individual segments, wherein each individual segment comprises a laminated core (13) around which a winding (11) is provided and end caps are provided at the axial end regions, wherein the winding (11) is produced by means of a winding wire, wherein a first end cap (12) of each individual segment is positively connected to a retaining ring (50), a potting cap (70) is positively connected to an end cap axially opposite the first end cap (12), wherein the potting cap (70) comprises at its axial end region, in particular at its axially projecting end region, recesses (31, 71) for the passage of stranded wire and / or recesses (31, 71) for the inlet of potting compound, wherein the recesses (31, 71) are arranged to be separated from one another by means of webs, wherein the webs are surrounded by potting compound, characterized by the fact that A shoulder (72) is provided at the axial end region of the potting cap (70) to create a space for a potting compound cover layer above recesses (31, 71) separating webs of the potting cap (70).

Description

[0001] The invention relates to an electric motor.

[0002] Electric motors whose stator comprises a laminated core are generally known. Preferably, such a laminated core is stamped.

[0003] From DE 198 57 954 A1 an electric motor is known with a stator composed of circumferentially arranged individual segments, wherein the end faces of the individual segments have spacers which are connected to retaining rings by means of locking hooks.

[0004] From DE 10 2005 051 506 A1 an electric motor is known with a retaining ring which is pushed onto the stator which is composed of individual segments.

[0005] From DE 15 13 749 A a trickle funnel is known which is connected to the slot lining of an electric motor by means of locking elements.

[0006] From DE 89 03 959 U1 an electric machine with a stator lamination stack is known.

[0007] A motor with potting compound is known from JP H06 - 70 497 A.

[0008] The invention is therefore based on the objective of simplifying the manufacture of an electric motor and improving the manufacturing quality during production.

[0009] According to the invention, the problem is solved in the electric motor according to the features specified in claim 1.

[0010] Important features of the invention in the electric motor are that the electric motor comprises a stator composed of individual segments arranged in the circumferential direction, wherein each individual segment comprises a sheet metal stack around which a winding is provided and end caps are provided at the axial end regions, where the winding is produced using a winding wire, wherein a first end cap of each individual segment is positively connected to a retaining ring, a potting cap is positively connected to an end cap axially opposite the first end cap.

[0011] An advantage of this design is the stable holding system that secures the entire stator lamination stack, composed of individual segmented lamination packages, before it is inserted into the motor terminal housing, particularly ensuring it maintains its intended circular shape. Two such holding elements, namely the retaining ring and the cap, are provided in the axial direction, thus guaranteeing a stable and secure fit.

[0012] In an advantageous embodiment, the potting cap projects axially beyond the stator housing of the electric motor, particularly in that the potting cap serves as a receptacle for receiving potting compound. It is advantageous that the cap defines the space for the potting compound and can be sealed to the motor housing and the lamination stack or end cap of the individual segments via sealing surfaces. Furthermore, it remains in the motor even after the potting compound has hardened, thus contributing to increased insulation strength.

[0013] In a preferred embodiment, the potting cap has a chamfer. This is advantageous because it improves the flow of the potting compound on the outside of the individual segment.

[0014] According to the invention, a shoulder is provided at the axial end region of the potting cap. An advantage of this is that it allows for the creation of a space for a potting compound top layer above the recesses separating the webs of the potting cap, thus providing greater stability against stress caused by vibrations and forces.

[0015] In a preferred embodiment, a locking lug is provided on the end cap, which interacts with a clip-in area on the retaining ring. The advantage here is that a simple, cost-effective connection type is sufficient for a stable connection and for maintaining the stator's circular shape.

[0016] According to the invention, the potting cap comprises, at its axial end region, particularly at its axially projecting end region, recesses for the passage of stranded wire and / or recesses for the inlet of potting compound, in particular wherein the recesses are arranged to be separated from one another by means of webs, and in particular wherein the webs are surrounded by potting compound. It is advantageous that the electrical wires and connection devices are held in a mechanically stable and electrically insulated manner. Thus, additional insulation is provided, as well as protection against vibrations.

[0017] In an advantageous embodiment, the retaining ring and / or the potting cap is made of plastic, in particular holding the individual segments together in a circular shape. An advantage of this is that at a joining temperature higher than the ambient temperature, the plastic loses strength, and thus radially protruding areas are compressible.

[0018] In an advantageous embodiment, an end cap comprises at least one dome, in particular for limiting the area of ​​the winding, wherein a wire entry channel is provided in the foot area of ​​the dome for wire guidance during winding and for optimal placement of the winding wire and deflection of the winding wire, wherein grooves are provided on the end cap, wherein the distance of one groove to the radially next groove and the rounding diameter of the respective groove are smaller than the winding wire diameter.

[0019] The respective dome is needed to catch the winding wire during the winding process. Its primary function is to deflect and guide the winding wire.

[0020] An advantage of this design is that the end cap protects both the laminated core and the winding wire. In particular, the end cap also provides electrical insulation. Furthermore, it improves the cohesion of the laminated core. In addition, the end cap's shape allows for precise definition and guidance of the winding during manufacturing. This compensates for spatial deviations in the winding tool's path, such as those of needle winders, ensuring consistent winding production. This improves the reproducibility of a desired winding and / or allows for increased winding speed, as larger path deviations become acceptable. Several features of the end cap contribute to this definition and guidance. First, the domes define the overall space within the winding.Furthermore, the deflection is implemented at a defined area at the base of the dome, which is also designed to withstand the maximum wire tensile force. The grooves also prevent radial slippage. The groove spacing is so small that, with correct path guidance, the same winding is always produced. Even with higher winding tool speeds and thus greater path deviations, a substantially identical winding can be achieved. While the first turn of the winding may shift radially by one groove spacing, the rest of the winding is constructed identically. Since the groove spacing is significantly smaller than the winding wire diameter, even a shift in the winding wire position by one groove spacing results in a substantially identical winding.

[0021] Furthermore, the grooves can be designed such that a winding wire running in a groove experiences a high holding force. In particular, if an adjacent winding wire in the next higher winding layer exerts a force on a winding wire below it that is held in a groove, the groove generates a corresponding counterforce. For this purpose, the groove is appropriately matched to the winding wire diameter. Preferably, the groove diameter is between one-tenth and one-half of the winding wire diameter.

[0022] Furthermore, it is advantageous that the end cap has shaping features on which the individual segments can be held together and aligned by a retaining element, such as a locking lug.

[0023] In a preferred embodiment, the first layer of the winding of the individual segment is positioned on the grooved surface area of ​​the end cap. The advantage here is that the grooves enable precise alignment of the winding.

[0024] In a preferred embodiment, a locking lug is provided on the end cap, which interacts with a clip-in area on the retaining ring that also acts as a sliding ring when inserting the stator into the motor housing. An advantage of this design is that the retaining ring allows the individual segments to be arranged in a circular shape, particularly before the stator is inserted into the motor housing.

[0025] In an advantageous embodiment, the retaining ring is made of plastic, particularly the part that holds the individual segments together in a circular shape. A key advantage is that the plastic, being much softer than the lamination stack, can be used to protect the edges of the stack. Specifically, the retaining ring can be chamfered to act as a guide when inserting the stator into a recess or bore in the motor housing. When inserted into the motor housing, the retaining ring protects the edges of the lamination stack, and the radially protruding portions of the retaining ring are even compressed. The compressed material of the retaining ring, which is particularly soft at higher temperatures, also acts as a lubricant during stator insertion. This prevents chip formation when the stator is pushed into the bore in the motor housing.

[0026] In an advantageous embodiment, the stator, including its retaining ring, is inserted into a recess in the motor housing. An advantage of this design is that the circular arrangement of the individual segments in the finished electric motor can be achieved, at least partially, through the recess in the motor housing, particularly through a borehole in the motor housing.

[0027] In an advantageous embodiment, radially projecting areas of the retaining ring are provided as lubricant during insertion into the recess. The advantage here is that the retaining ring functions, so to speak, as a lubricant container or reservoir, making lubricant readily available during insertion.

[0028] In an advantageous embodiment, the lamination stacks of the individual segment are positively connected to one another, in particular positively in the radial and circumferential directions. An advantage of this is that it allows for cohesion of the stator.

[0029] In a preferred embodiment, the sheet metal stacks of the individual segment are positively connected to one another by means of a tongue-and-groove joint. The advantage here is that a simple and secure connection, which is also backlash-free, can be used.

[0030] In an advantageous embodiment, the distance between a groove and the radially next groove, and the radius of curvature of each groove, is less than half the winding wire diameter. In particular, the distance is one-third of the winding wire diameter or less. The advantage here is that a reproducible winding can be produced very quickly using a needle winder.

[0031] In an advantageous embodiment, the end cap provided at the first axial end region of the individual segment and the end cap provided at the second axial end region of the individual segment are connected by means of at least two connecting webs or by means of at least one connecting web that is at least ten times wider in the radial direction than in the circumferential direction, wherein the connecting web(s) are provided in one or more corresponding recesses in the sheet metal stack. It is advantageous that the torsional stiffness of the individual segment is increased after the connecting webs are attached.

[0032] In an advantageous embodiment, the end caps and / or the connecting bridge(s) are manufactured by overmolding the sheet metal assembly; in particular, the end caps and a connecting bridge are formed in one piece. This has the advantage of enabling simple manufacturing of the plastic parts.

[0033] In an advantageous embodiment, the end cap has a retaining shoulder designed for positive-locking connection with a tool of the winding machine, particularly during the winding process. This design is advantageous because it prevents the end cap from slipping due to forces occurring during winding.

[0034] In a preferred design, the motor housing is an extruded aluminum part. The advantage here is that motors with different axial lengths can be easily manufactured without special additional effort, thus enabling the simple production of a modular system of motors with different torques.

[0035] In a preferred design, the winding machine is of the type of needle winder. An advantage of this is that complex web paths can be processed quickly during winding.

[0036] In an advantageous embodiment, the connecting web has reinforcing ribs extending in the axial and / or radial direction, particularly those projecting circumferentially. This has the advantage of improving torsional stiffness.

[0037] Further advantages arise from the sub-claims.

[0038] The invention will now be explained in more detail with the help of illustrations: In the Fig. Figure 1 shows a stator of an electric motor according to the invention, which is made up of individual segments held together by a retaining ring. In the Fig. 2a shows such a single segment without a retaining ring from a first viewing angle. In the Fig. 2b shows this single segment from a different viewpoint. In the Fig. Figure 3 shows the single segment unwrapped without insulating paper. In the Fig. 4a is a first end cap for the single segment shown from a first viewing angle. In the Fig. 4b shows this first end cap from a second viewing angle. In the Fig. Figure 5a shows the retaining ring in a top view. In the Fig. Figure 5b shows the retaining ring in a perspective view. In the Fig. Figure 6 shows a cross-section through an area of ​​the single segment. In the Fig. Figure 7 shows the motor housing with axially protruding potting cap. In the Fig. 8a shows the potting cap in a first oblique view and in the Fig. 8b is shown under a second oblique view from a different perspective. Fig. Figure 8c shows a section in the area of ​​the snap-fit ​​connection between the second end cap, which sits axially on the sheet metal stack, and the potting cap. In the Fig. Figure 9 shows the potting cap 70 mounted on the motor housing, with the potting compound hidden.

[0039] As in the Fig. As shown in Figure 1, the stator of the electric motor according to the invention is composed of individual segments arranged one after the other in the circumferential direction. A retaining ring 50 is pushed onto the stator, the clip-in connection areas 51 of which each hold an individual segment positively connected, so that the cylindrical shape of the stator, i.e. the circular orientation of the individual segments, is achieved.

[0040] Each individual segment comprises a sheet metal stack 13, onto which a plastic end cap (12, 30) is slid at both axial end regions. The first end cap is located axially on the motor output side, and the second end cap is located axially on the opposite side. The winding of each individual segment is carried out automatically, and a needle winder can be used.

[0041] Preferably the end cap (12, 30) is constructed in a mirror-symmetrical manner, with the axis of the motor lying in the mirror plane.

[0042] The end cap also absorbs the forces caused by wire tension, especially during wire deflection.

[0043] The first end cap 12 has domes 1 which serve to deflect the winding wire at the entry or exit point, with wire entry channels 2 being provided at the base of the domes 1. These wire entry channels ensure optimal positioning of the first turn of the winding.

[0044] All subsequent windings are based on the first turn, meaning they are positioned relative to the first turn. Therefore, with optimal positioning of the first turn, a high fill level can be achieved.

[0045] The first layer of windings is placed on the grooved surface of the end cap. This prevents the winding wires of the first layer from slipping when the second layer of windings is applied, as it rests on top of the first layer. This is because the grooves generate counterforces to the forces acting on the first layer from the second layer.

[0046] The distance from one groove to the next groove perpendicular to the groove, i.e. in the radial direction of the electric motor, and the rounding diameter of the respective groove are much smaller than the winding wire diameter.

[0047] To generate the greatest possible counterforce, the groove diameter is larger than one-tenth and smaller than half the winding wire diameter. A groove diameter of one-third, one-quarter, one-fifth, or a value in between has proven particularly advantageous.

[0048] The locking lugs 4 serve to lock the retaining ring 50 and a cap produced from the casting of the stator after its completion.

[0049] The end cap also features a retaining shoulder 5, which serves to positively lock the end cap to the respective individual segment, and which can be created by a suitably shaped workpiece carrier. This prevents slippage due to the forces occurring during winding.

[0050] In Fig. 2a and Fig. Figure 2b shows the paper-enclosed winding 11 in the single segment. At the axial end, the second protective cap 12 is pushed onto the lamination stack 13, into whose recess 31 the stamped-bent part 10 is inserted, thus allowing connecting wires to be electrically connected to the winding wire electrically connected to this stamped-bent part 10, in particular soldered or welded on.

[0051] The electrical connections are also electrically connected to the stamped-bent part 10. Preferably, a stranded wire is inserted into the stamped-bent part 10 and then clamped in place by bending the part. A welded or soldered connection is then made between the stamped-bent part 10 and the stranded wire. The winding wire is also electrically connected to the stamped-bent part 10 in a similar manner.

[0052] In Fig. Figure 3 shows the unwound single segment with a first end cap 12 and a second end cap 30, which are pushed onto the two axial end regions of the single segment. The recess 31 in the second end cap 30 serves to fix the stamped-bent part 10, in particular contact hooks.

[0053] The second end cap 30 has indentations on its inside which also serve to precisely guide the first winding wire entering from the stamped-bent part 10, in particular the contact hook, and thus act as a wire guide when producing the first turn of the winding.

[0054] At least one end of the winding wire is electrically connected to the stamped and bent part 10, in particular the contact hook, in particular by welding or soldering, and also an end of a stranded wire which is brought out as an electrical connection device.

[0055] In the Fig. Figure 4a shows the first end cap 12 enlarged, showing that the domes 1 protrude radially beyond the winding area.

[0056] In the Fig. 5a the six clip-in connection areas 51 on the retaining ring 50, which are evenly spaced apart in the circumferential direction, are visible.

[0057] In the Fig. Figure 6 shows a cross-section through the first end cap 12 with its dome 1 and wire entry channel 2, as well as the locking lug 4, which positively engages the retaining ring 50 at its clip-in connection area 51. Fig. Although this clip-in connection area 51 and the locking lug 4 do not touch, the distance shown is within the manufacturing tolerance range, so that with the large number of clip-in connections on the circumference of the retaining ring 50, the connection has a very small or even negligible play.

[0058] To manufacture the electric motor, the in Fig. Figure 1 shows the stator being inserted into the hole-shaped recess of a motor housing. The recess is machined as a bore, in particular by milling and / or turning, and can therefore also be referred to as a stator bore. To insert the stator, the motor housing is heated, causing the recess to expand. After cooling, the stator is held securely in place. The insertion temperature is between 150°C and 300°C.

[0059] The plastic retaining ring 50 is provided with a chamfer or bevel around its entire circumference to facilitate the insertion of the stator held together by the retaining ring 50. This chamfer has an increasing radius in the axial direction. The stator is thus positioned against the recess in the motor housing using this chamfer and then inserted.

[0060] The plastic of the retaining ring 50 does not melt at the joining temperature, but it also no longer possesses its nominal strength. Therefore, the excess material of the retaining ring, i.e., the radially protruding areas beyond the bore, is compressed and smeared along the axial direction on the outer circumference of the stator lamination stack during insertion. In this way, a lubricating effect is achieved, thus protecting the bore from the sharp edges of the lamination stack and enabling insertion with less friction. A particularly advantageous aspect is that chip formation is prevented when the stator is inserted into the bore in the motor housing.

[0061] The retaining ring 50 thus serves two purposes: firstly, to hold the individual segments in place, and secondly, parts of its material act as a lubricant during insertion. Once inserted, the stator is held partly by the remnants of the retaining ring and partly by the motor housing. Further retention is achieved by encasing the stator in potting compound. Therefore, the holding function of the motor housing alone is insufficient.

[0062] Preferably, the motor housing is manufactured as an aluminum extrusion profile.

[0063] In other embodiments of the invention, instead of the one described in Fig. 5a Six clip-in connection areas 51 are provided on the retaining ring 50, spaced evenly apart in the circumferential direction. Instead of six or twelve, a number between 9 and 27 has also proven advantageous.

[0064] In the Fig. Figure 7 shows the motor housing with axially projecting potting cap 70.

[0065] In the Fig. 8a shows the potting cap 70 in a first oblique view and in the Fig. 8b shown in a second oblique view from a different viewing direction.

[0066] The potting cap 70, like the retaining ring 50, is pushed onto the lamination stack and positively connected, in particular by clipping it in place, although this is done from the other axial end of the lamination stack. Thus, the potting cap 70 also helps to hold the individual segments together in a circular shape.

[0067] After the stator is inserted into the bore of the motor housing, the potting cap 70 protrudes axially and has a recess 71 for the passage of stranded wire and a recess 73 as an inlet opening for potting compound. The stranded wire is thus guided from the stamped-bent part 10 through the recess 71 to the outside. Potting compound is poured in through the recess 73, thereby encasing the portion of the stranded wire running inside the potting cap.

[0068] Thus, the electrical interconnection of the segments, i.e., the electrical connections between the winding wire ends and the external stranded wire sections, is enabled axially outside the motor housing, specifically within the area enclosed by the potting cap. The winding wire sections, stranded wire sections, and the stamped and bent parts 10 (i.e., contact hooks) located within this area are surrounded by the potting compound and thus stabilized against vibrations. The potting cap simplifies the potting process and remains on the stator even after potting, thereby providing a retaining function. Furthermore, it has insulating properties and thus increases the insulation distance to live parts.

[0069] In the circumferential direction, the recesses 71 and 73 are each spaced apart from one another by webs. Each recess thus allows stranded wire to be led out in a position defined by the recess or at least in a spatial area defined by the recess.

[0070] The recess 72 provided in the axial end region of the potting cap 71 serves as a space for a resin covering layer above the webs.

[0071] A circumferentially uniform chamfer 75, provided at the axially opposite end region, improves the flow of the potting compound, preferably a resin, on the outer surface of the segment. A further chamfer facilitates insertion into the motor housing. As with the retaining ring 50, the radially projecting areas are compressed during insertion into the motor housing 71, and the potting cap thus acts as a lubricant reservoir.

[0072] Sealing surfaces 74 are shaped in such a way that they create such a tight connection with the stator lamination stack or with the motor housing that the potting compound hardens completely or at least substantially within the space defined by the potting cap 70.

[0073] The locking elements 76 provided on the inside enable a clip-in connection, i.e. a positive locking connection, with the second end cap 30, which is pushed onto or molded onto the stator lamination stack 13 and can therefore be used as a safeguard against axial slippage.

[0074] The in Fig. The snap-fit ​​connection with the sheet metal stack shown in 8c corresponds in principle to the snap-fit ​​connection of the retaining ring 50 according to Fig. 6. Reference symbol list 1 Dome of the first end cap 2 wire inlet channel 3 grooves 4 locking tabs 5 Holding step 10 Stamped and bent parts, in particular contact hooks 11 paper-enclosed windings 12 first end cap 13 sheet metal package 30 second end cap 31 Exclusion 32 Wire inlet for wire guidance during winding 50 retaining ring 51 Clip-in connection area 70 potting cap 71 Exclusion for the installation of stranded wire Paragraph 72 73 Recess as inlet opening for potting compound 74 sealing surface 75th phase 76 locking elements

Claims

Electric motor comprising a stator composed of circumferentially arranged individual segments, wherein each individual segment comprises a laminated core (13) around which a winding (11) is provided and end caps are provided at its axial end regions, wherein the winding (11) is produced by means of a winding wire, wherein a first end cap (12) of each individual segment is positively connected to a retaining ring (50), a potting cap (70) is positively connected to an end cap axially opposite the first end cap (12), wherein the potting cap (70) comprises, at its axial end region, in particular at its axially projecting end region, recesses (31, 71) for the passage of stranded wire and / or recesses (31, 71) for the inlet of potting compound, wherein the recesses (31, 71) are arranged separated from one another by means of webs, wherein the webs are surrounded by potting compound, characterized in thatthat a shoulder (72) is provided at the axial end region of the potting cap (70) to create a space for a potting compound cover layer above recesses (31, 71) of the potting cap (70) separating webs. Electric motor according to claim 1, characterized in that the potting cap (70) projects axially beyond the stator housing of the electric motor, in particular wherein the potting cap (70) is provided as a receiving container for receiving potting compound. Electric motor according to at least one of the preceding claims, characterized in that the potting cap (70) has a chamfer (75) to improve the flow of the potting compound on the outside of the individual segment. Electric motor according to at least one of the preceding claims, characterized in that a locking lug (4) is provided on the end cap (12) which interacts with a clip-in area on the retaining ring (50). Electric motor according to at least one of the preceding claims, characterized in that the retaining ring (50) and / or the potting cap (70) is made of plastic. Electric motor according to at least one of the preceding claims, characterized in that the stator together with retaining ring (50) is inserted into a recess (31) of the motor housing, in particular an aluminum extrusion casting part, in particular wherein the stator together with a part of the potting cap (70) is inserted into the recess (31) of the motor housing. Electric motor according to claim 6, characterized in that radially projecting areas of the retaining ring (50) and / or the potting cap (70) are provided as lubricants when inserted into the recess (31). Electric motor according to at least one of the preceding claims, characterized in that the lamination stacks of the individual segment are positively connected to each other, in particular positively in the radial and circumferential direction. Electric motor according to at least one of the preceding claims, characterized in that the lamination stacks of the individual segment are positively connected to each other by means of a tongue-and-groove connection. Electric motor according to at least one of the preceding claims, characterized in that an end cap (12) comprises at least one dome (1), in particular for limiting the area of ​​the winding (11), wherein a wire entry channel (2) for wire guidance during winding of the winding wire is provided in the foot area of ​​the dome (1), in particular wherein grooves (3) are provided on the end cap (12), wherein the distance of a groove to the radially nearest groove and the radius of curvature of the respective groove are smaller than the winding wire diameter, and / or that the distance of a groove to the radially nearest groove and the radius of curvature of the respective groove is smaller than half the winding wire diameter, in particular greater than one tenth of the winding wire diameter, and in particular preferably selected from the range of one fifth to one third of the winding wire diameter. Electric motor according to at least one of the preceding claims, characterized in that the end cap (12) provided at the first axial end region of the individual segment and the end cap (12) provided at the second axial end region of the individual segment are connected by means of at least two connecting webs or by means of at least one connecting web which is at least ten times wider in the radial direction than in the circumferential direction, wherein the connecting web(s) are provided in one or more corresponding recesses (31, 71) of the lamination stack (13), in particular wherein the end caps and / or the connecting web or the connecting webs are manufactured by overmolding the lamination stack (13), in particular the end caps and a connecting web are formed in one piece. Electric motor according to at least one of the preceding claims, characterized in that the first layer of the winding (11) of the single segment is provided on the grooved surface area (3) of the end cap (12). Electric motor according to at least one of the preceding claims, characterized in that the end cap (12) has a retaining shoulder (5) which is provided for positive locking connection with a tool of the winding machine, in particular needle winder, in particular during the production of the winding, in particular to prevent the end cap (12) from slipping due to forces occurring during the winding. Electric motor according to at least one of the preceding claims, characterized in that the connecting web has reinforcing ribs extending in the axial direction and / or in the radial direction, in particular projecting in the circumferential direction.

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