WO2017036687A1

WO2017036687A1 - Stator having an insulated bar winding for an electric machine

Info

Publication number: WO2017036687A1
Application number: PCT/EP2016/067946
Authority: WO
Inventors: Bodo Von Moltke; Nurdin PITAREVIC; Aleksandr VASSILJEV
Original assignee: Continental Automotive Gmbh
Priority date: 2015-09-03
Filing date: 2016-07-27
Publication date: 2017-03-09
Also published as: EP3345284A1; CN107852056B; CN107852056A; DE102015216840A1

Abstract

The invention relates to a stator (1) for an electric machine (34), comprising a laminated core (2), which has grooves (4), which extend in the axial direction (3) of the stator (1), and comprising electrically conductive bars (21), which are electrical windings of the stator (1), at least one of said bars being arranged in each groove (4), wherein each bar (21) is electrically insulated from the laminated core by means of a respective electrical insulating element (22). The production of the stator (1) should be efficient. According to the invention, each electrical insulating element (22) is designed as a tube element (23), which is formed of a thermoplastic plastic and surrounds the bar (21).

Description

description

Stator insulated bar winding for an electrical machine The invention relates to a stator for an electric Ma ^¬ machine, an electric machine with the inventive stator, a motor vehicle and a method of manufacturing the stator. The stator has a laminated core with grooves, in each of which at least one electrically conductive rod is arranged, the entirety of the rods representing electrical windings of the stator. Each rod is insulated by means of an electrical insulation element against the laminated core.

In a stator of the type mentioned is provided in the prior art to coat each electrically conductive rod with an electrically insulating paint. Subsequently, the rod is installed in the groove of the laminated core and fixed by means of an insulating paper. Finally, the insulation ^¬ paper is impregnated with a potting compound, namely an impregnating resin. As a result, the rod is fixed in the groove and insulated against the laminated core.

This known from the prior art manufacturing process is time consuming, since the arrangement of the rods together with the insulation paper requires a high precision. In addition, the impregnation of the insulation paper and the subsequent curing of the potting compound take several hours.

The invention is based on the object, an efficiently producible electric machine especially for a

To provide motor vehicle.

The problem is solved by the subject matters of the independent Pa ^¬ tentansprüche. Advantageous developments of the invention are given by the features of the dependent claims. The invention provides a stator for an electrical machine. In a manner known per se, the stator has a laminated core with grooves which extend in the axial direction of the stator. The axial direction is aligned along the intended rotational axis of the rotor to be arranged in the stator. The stator further comprises electrically conductive, electrical windings of the stator performing rods, each of which at least one is arranged in one of the grooves. In other words, the stator has a bar winding. Preferably, two bars per groove are arranged and the bars mitei ^¬ interconnected to a two-layer winding. Each rod is electrically insulated from the laminated core by a respective electrical insulation element.

Unlike the prior art, the electric isolati ^¬ onselement is now but not by a lacquer layer and impregnated with a sealing compound insulating paper formed. Instead, it is provided for efficient production of the stator, that the respective electrical insulation element of each rod is designed as a hose member which is formed from a ^{thermoplastic} plastic and which encloses the respective rod. In other words, each rod is surrounded or wrapped in length by the plastic. In other words, each rod has a sheath made of the plastic.

The advantage of the invention is that each bar can be produced or made available separately together with its electrical insulation element. Each rod can then be stuck together with its electrical insulation element finished in the groove. Then then no further processing steps are necessary to isolate the rod against the laminated core. The invention also includes optional developments, by the characteristics of which additional benefits. According to a further development of the plastic of the respective hose member is arranged by means of an extrusion method according to the ^¬ weiligen rod. In other words, the plastic is arranged or poured in the soft or flowable state by extrusion around the rod. This has the advantage that the rods can be successively provided mechanically with their respective electrical insulation element in a continuous or continuous extrusion process. This makes the production even more efficient.

According to a development, a groove width of the respective groove in which the hose element is arranged, at most 0.2 millimeters, in particular 0 millimeters, greater than an outer diameter of the hose member itself. In other words, results in the circumferential direction of the stator, a game or a free space of the Stabs together with its hose element in each groove, which is at most 0.2 millimeters, in particular at most 0 millimeters. This has the advantage that each rod can be fixed or fastened with little effort in the groove. For example, it may be sufficient to fold over or bend out of the laminated core projecting ends of the rod, so that the rod sits firmly together with its tubular element in the groove. A development for this purpose provides that the rod is plastically and / or elastically bent in the groove and thereby has a mechanical stress that presses the hose member against a groove wall of the groove. This results in the advantage that a heat conduction between the laminated core and the rod is ensured or guaranteed. The bending can be achieved, for example, by the described bending or bending of the rod ends, which protrude from the laminated core.

According to a development, a wall thickness of the hose element of each rod is in a range of 0.1 millimeter to 0.5 millimeter. For example, the wall thickness

0.3 millimeters. In other words, there is one between the rod and the laminated core in each direction Plastic layer having a thickness or wall thickness in a range of 0.1 millimeter to 0.5 millimeters. This results in the advantage that each rod is reliably insulated electrically against the laminated core by means of the hose element alone. Furthermore, given the dimensions mentioned also a reliable heat conduction.

According to a development, the grooves are free of one

Sealing compound. In other words, the pouring with the potting compound, for example the impregnating resin described, is dispensed with in the stator. As a result, this time-consuming production step is avoided.

According to a development, the plastic comprises, for example, a polyamide and / or a polyphenylene sulfone (PPSU) and / or a polyphthalamide (PPA) or it is formed therefrom. These plastics have been found to be particularly advantageous in the use of a stator made in the manner described.

With regard to the bars themselves, a further development provides that each bar is made of copper. This results in an electrical conductivity that is suitable for providing the winding. Furthermore, the deformability of the rod is additionally ensured in order to press the plastic of the hose member by a deflection of each rod against a groove wall.

The invention also includes an electric machine having an embodiment of the stator according to the invention. In the stator, a rotor of the electric machine is rotatably mounted. The electric machine can be manufactured with particularly little Ar ^¬ beitsschritten, since the stator in the manner described can be manufactured by common, simultaneous insertion of the bars together with their insulation member in the lamination stack and then bending of the rod ends.

It is particularly preferred that the electrical Ma ^¬ machine as a starter generator for a motor vehicle or Electric motor is designed for a brake assist system of a motor vehicle. In these two applications, it has been shown that the stator, which is produced in the manner according to the invention, has sufficient heat transfer between the rods and the Bleckpaket, so that in particular the missing potting compound is no disadvantage.

Finally, the invention also includes a motor vehicle in which the electrical machine is provided or arranged in the manner described.

In order to produce an embodiment of the stator according to the invention, the invention also provides a method for producing an embodiment of the stator according to the invention. In the method according to the invention, a laminated core is provided with grooves which extend in a be ^¬ known manner in the axial direction of the stator. At least one electrically conductive rod is be ^¬ riding provided for each groove. As already stated, preferably two rods per groove are provided. In order to be able to arrange the rods in the groove and to provide an electrical insulation or insulation between each rod and the laminated core with a few steps, it is provided according to the invention that each rod provided is surrounded by a tubular element formed of a thermoplastic plastic, which represents the already described electrical insulation element. Each bar is along with the ge ^¬ puts it in each case by ^¬ imaging tube element in each corresponding groove. In other words, therefore, after the insertion of each rod in the respective groove at the same time also the electrical

Insulation of the rod against the laminated core ensured. So there is no additional work required after inserting each rod to ensure electrical insulation. In order to provide the described rods with the respective hose element, a further development provides that for the provision of the rods a wire is provided around which the plastic is arranged by means of an extrusion method. The wire and the plastic are cut into the bars and hose elements. In other words, in ^¬ example, a role with the wire, which is already covered by the plastic, are provided. By unrolling the wire from the roll and cutting or splitting the wire into the individual bars, each bar can be provided in an automated manner. Here, the plastic may be arranged continuously along the wire. In order then to provide the hose elements, it can be provided that ends of the bars are stripped, that is, the plastic is removed.

The wire may be, for example, a round wire or a flat conductor.

By providing the rods together with their tubular element before they are inserted into the respective groove, each rod can advantageously be inserted together with its respective tubular element into one of the grooves according to an embodiment. The hose element adheres in particular to the rod, so that an adjustment of each

Hose element in the groove is unnecessary or can be omitted.

A further embodiment provides that each rod inserted into one of the grooves is deformed by bending and thereby the respective tubular element of the rod is pressed against a groove wall of the respective groove. This results in a

Contact contact between the hose element and the groove. Ins ^¬ particular so as to ensure an air-free transmission of heat between the core and the rod.

In the following an embodiment of the invention is described. 1 shows a schematic representation of a perspective view

View of an embodiment of the stator according to the invention, 2 shows a schematic representation of the stator of FIG. 1, wherein only a single electric coil is shown, FIG.

Fig. 3 is a schematic representation of a cross section of the

Stators,

Fig. 4 is a schematic representation of a perspective

View of a single conductor element of the stator,

Fig. 5 is a schematic representation of a side view of the

Ladder element,

Fig. 6 is a schematic representation of a cross section of the

Ladder element, and

Fig. 7 is a schematic representation of an embodiment of the motor vehicle according to the invention.

The exemplary embodiment explained below is a preferred embodiment of the invention. In the exemplary embodiment, the described components of the embodiment each represent individual features of the invention that are to be considered independently of one another, which also each independently further develop the invention and thus also individually or in a different combination than the one shown as part of the invention. Furthermore, the described embodiment can also be supplemented by further features of the invention already described.

In the figures, functionally identical elements are each provided with the same reference numerals.

Fig. 1 shows a stator 1 for an electric machine. The stator 1 may be provided, for example, for a starter-generator of a motor vehicle. The stator 1 has a laminated core 2 which, in a manner known per se, consists of soft-magnetic sheet metal layers (coercive field strength less than 1000 A / m). ₀

O

may be formed, which are electrically insulated from each other and stacked or layered along an axial direction 3. In grooves 4 of the laminated core 3 5 conductor elements 6, 7 have been inserted in each case by an axial slot opening. For the sake of clarity, only a few of the elements mentioned are provided with a reference numeral. The conductor elements 6, 7 of each groove 4 are arranged in alignment in a radial direction 8 one behind the other. The radial direction 8 is in each case directed perpendicularly outward from an axis 9, by which the axial direction 3 is fixed. The axis 9 corresponds to the intended rotational axis of a rotor which can be arranged in the stator.

The different radial distances between the conductor elements 6, 7 result in two rings or layers 10, 11, the radially outer conductor elements 6 representing the layer 10 and the radially inner conductor elements 7 the layer 11. The layers 10, 11 are part of a two-layer winding 12 of the stator 1. The two-layer winding 12 comprises in the example shown six electric coils, each of which results by interconnecting a respective subset of the conductor elements 6, 7. In each case a conductor element of the outer layer 10 and a conductor element of the inner layer 11 forms a phase terminal or coil terminal 13 of one of the coils. The coil terminals 13 of a coil are each arranged in a connection region 14. Fig. 2 shows by way of illustration a single electrical coil 15. The illustration in Fig. 2 corresponds to the illustration in Fig. 1, wherein all those conductor elements 6, 7 are hidden, which belong to the other electric coils. The coil 15 shown in FIG. 2 has a total of three loops or turns 16, which are electrically interconnected within the interconnection region 14 by a winding connection 17. _

y

To form the turns 16 of the coil 15, the conductor members 6 of the outer layer 11 have been chamfered or bent along a circumferential direction U L, while the conductor members 7 of the inner layer 11 have been bent in an opposite circumferential direction U 2. As a result, the conductor elements 6, 7 of the two layers 10, 11 are entangled with each other, so that a skew region has a helix angle with respect to

End face 18 has. The conductor ends further comprise conductor ends which are aligned parallel to the axis 9. The conductor ends have for this purpose a crank.

The helix angles of all helical regions of the conductor ends are the same. As a result, the conductor ends are particularly close together. The conductor ends are part of a winding head 20 on the end face 18 of the laminated core 2.

FIG. 3 shows how the electrical conductor elements 6, 7 are electrically insulated in the interior of the laminated core against the soft-magnetic sheet metal layers of the laminated core 2. For the sake of clarity, only a few reference symbols for the elements mentioned in FIG. 3 are assigned in each case. Each conductor element 6, 7 is formed from an electrically conductive rod 21 and an electrical insulation element 22. Fig. 4 shows once again a single electrical conductor element 6, 7 in isolation with the electrically conductive rod 21 and the electrical insulation element 22. The rod 21 may each be a flat conductor or a flat wire. A material of the rod 21 may e.g. Be copper. The electrical insulation element 22 is configured as a casing or hose element 23.

Fig. 3 illustrates how each rod 21 is electrically insulated from the laminated core 2 by the material of the hose element 23 by means of the insulating element 22. The hose element 23 is formed from a thermoplastic material, which may comprise, for example, a polyamide and / or PPSU and / or a PPA. FIG. 3 further illustrates how, due to the entanglement or bending in the region of each winding head 20 shown in FIG. 1, each rod 21 presses the respective hose element 23 against a groove wall 24 of the respective groove 4, the rod 21 being mechanically distorted or bent.

The plastic of the hose member 23 may have been applied to the rod 21 by an extrusion process. For this purpose, each rod 21 or a wire, from which the rods 21 are to be manufactured by cutting, by a

Extrusion arrangement (not shown) out. This contains an annular gap from which the plastic exits in a deformable or liquid or flowing state. This creates a tube that applies to the rod 21 or the wire.

Fig. 5 shows how, when manufacturing the rod 21 from a wire, this wire is divided into rods 21 having the rod length 25. In this case it can be provided that stripped ends 26 are formed by stripping or removing from the rod 21 the plastic of the hose member 23 so that each hose member 23 has an insulation length 27 smaller than the rod length 25. A rod length can e.g. in a range of for example 8 centimeters to 15 centimeters.

Figure 6 illustrates how the rod 21 surrounds the rod 21 with the plastic, the tubular member 23 having a layer thickness or wall thickness 28 which may be in the range of 0.1 millimeter to 0.5 millimeter.

Preferably, edges 29 of the rod 26 have curves or a radius of curvature 30 which is in a range of 0.5 millimeters to 1.5 millimeters. This results in the advantage that the hose member 23 is not cut or cut by the edge 29 during vibration movements.

An outer diameter 32 of the conductor member 6, 7, that is, an outer diameter 32 of the hose member 23 in the circumferential direction Ul, U2, is at most 0.2 millimeters smaller or smaller than a groove width 33 in this direction. Preferably, the tube member 23 contacts both opposing groove walls. FIG. 7 illustrates how an electric machine 34 can be provided by means of the stator 1. In the electric machine 34, a rotor 35 is rotatably mounted in the stator 1. The rotor 35 is rotatably connected to a shaft 36. The electric machine 34 may be installed, for example, in a motor vehicle 37. The motor vehicle 37 may be, for example, a motor vehicle, in particular a passenger car or truck. The shaft 36 may be coupled to a vehicle component 38, which may be, for example, an internal combustion engine or a pump for a hydraulic brake circuit of a brake assist system. The electric machine 34 can be driven in a manner known per se by alternately energizing the electric coils of the stator 1 by means of an inverter or inverter. This creates a magnetic rotating field in the stator, which drives the rotor 35. The rotor 35 then rotates about the axis 9.

Overall, the example shows how one can provide by extrusion on ^¬ placed plastic coating, an electrical insulation of the copper rods of a stator. The art ^¬ material layer thickness can thus be selectively adjusted, that can be extruded or extruded rod pin installed directly in the groove 4 of the laminated core 2 and then folded or bent or vertwistet. The advantage over the prior art is that the costly process of

Groove insulation can be omitted. In particular, it is not necessary to insert insulation paper in the grooves and then to impregnate the insulation paper with an impregnating resin. The further advantage is that the damage of the insulation paper or an insulating lacquer layer on the rod also can not occur. The tubular element of the thermoplastic material is flexible and adapts to the shape of the rod when bending or vertwist. The hose element made of plastic also has sufficient mechanical strength and the layer thickness of the plastic coating can still be chosen sufficiently low.

This results in an overall saving of manufacturing ^¬ or process steps as well as an accompanying reduction in costs. Furthermore, the stator 1 can be manufactured in a shorter period of time. The applied by extrusion plastic coating has improved mechanical strength compared to a coating of the rods 21 with an electrically insulating paint and subsequent fixation of the rods in the grooves 4 by means of insulating paper and potting compound.

Overall, thus shows the example of how can be used by the invention, a thermoplastic sheath of flat conductors for the production of motor windings.

Claims

claims

A stator (1) for an electric machine (34) comprising a laminated core (2) having grooves (4) extending in the axial direction (3) of the stator (1) and electrically conductive electrical windings the stator (1) depicting ^¬ lumbar rods (21) of which is disposed respectively at least one in one of the grooves (4), each rod (21) by a respective electrically insulating member (22) is electrically insulated from the laminated core, dadurchgekenn ^¬ records that the respective electrical insulation ^¬ element (22) as a hose member (23) is configured, which is formed of a thermoplastic material and which surrounds the rod (21).

Second stator (1) according to claim 1, wherein the plastic of the j eweiligen hose member (23) by means of an extrusion method to the respective rod (21) is arranged.

3. stator (1) according to one of the preceding claims, wherein a respective groove width (33) of the groove (4), in which the

Arranged tube element (23), at most 0.2 mm, especially not more than 0 mm, is larger than a Au ^¬ ßendurchmesser (32) of the hose member (23).

4. stator (1) according to any one of the preceding claims, wherein the rod (21) in the groove (4) is plastically and / or elastically bent and thereby has a mechanical stress, the hose member (23) against a groove wall (24). the groove (4) presses.

5. stator (1) according to any one of the preceding claims, wherein a wall thickness (28) of the hose member (23) is in a range of 0.1 millimeters to 0.5 millimeters.

6. stator (1) according to any one of the preceding claims, wherein grooves (4) are free of a potting compound.

7. stator (1) according to any one of the preceding claims, wherein the plastic comprises or is formed from polyamide and / or polyphenylene sulfone and / or polyphthalamide.

8. stator (1) according to any one of the preceding claims, wherein each rod (21) is formed of copper.

9. Electrical machine (34) with a stator (1) according to one of the preceding claims, wherein in the stator (1) a rotor (35) is rotatably mounted.

10. Electrical machine (34) according to claim 9, wherein the electric machine (34) as a starter generator or as

Electric motor for a brake assist system of a motor vehicle (37) is configured.

11. Motor vehicle (37) with an electric machine (34) according to claim 9 or 10.

12. A method for producing a stator (1) according to any one of claims 1 to 8, wherein in the method, a laminated core (2) having grooves (4) extending in the axial direction (3) of the stator (1) is provided and for each groove (4) at least one electrically conductive rod (21) is provided, characterized in that each be ^¬ prepared rod (21) is surrounded by a formed of a thermoplastic resin hose member (23) and each rod (21) together with the tubular element (23) surrounding it is inserted into the respectively provided groove (4).

13. The method of claim 12, wherein for providing the rods (21), a wire is provided, around which by means of an extrusion method, the plastic is arranged, and the wire in the rods (21) and the plastic is divided into the hose members (23) ,

14. The method of claim 12 or 13, wherein each rod (21) is inserted together with its respective hose member (23) in one of the grooves (4).

15. The method according to any one of claims 12 to 14, wherein each in one of the grooves (4) inserted rod (21) is deformed by bending and thereby the respective hose member (23) of the rod (21) against a groove wall (24) of the j Meanwhile groove (4) is pressed.