Stator with impregnation aid in winding slots with open-pore structure and / or with flow brake

Abstract

The invention relates to a stator (1) for an electric machine, with a substantially ring-shaped base body (2) having several slots (3) distributed along a circumference, and a coil winding (4) arranged at least partially in the slots (3), wherein a foam-like / open-pore structure (13) is arranged between a slot base (5) limiting the respective slot (3) in a radial direction and a wire section (6) of the coil winding (4) nearest to this slot base (5).

Description

[0001] The invention relates to a stator for an electrical machine, preferably an electric drive machine of a motor vehicle, with a substantially annular base body having a plurality of grooves distributed along a circumference, and a coil winding arranged at least in sections in the grooves.

[0002] Known stators and electrical machines with these stators are already well known from the prior art. Internal prior art known to the applicant relates, for example, to a method for producing a power-generating component of an electric rotary machine, in which a base body of the power-generating component is provided with a plurality of slots, each extending along a longitudinal direction, and conductor strands of at least one winding are provided in the slots.In addition, at least one slot wedge is provided for closing at least one slot with respect to an air gap of the electric rotary machine. At least one flow channel is formed in the slot wedge for introducing a curable medium into the slot, said flow channel having at least a first channel section extending along the longitudinal direction of extent and at least a second channel section extending transversely to the longitudinal direction of extent. The slot wedge is arranged in or on a slot such that the second channel section opens into or on the slot, and curable medium is guided in a flow through the flow channel in the slot wedge into the slot and is cured there.

[0003] It has been found that when filling the respective groove with casting compound, such as resin, the groove base in particular is often not sufficiently impregnated / filled with the casting compound. Furthermore, it has been found that since the casting compound is only applied into the notes from one (axial) side of the base body, too much of it often runs out the other, opposite side of the base body. Here, too, the result is insufficient impregnation of the groove base with the casting compound.

[0004] An unintentional shift of wire sections of the coil winding can therefore occur during operation.

[0005] It is therefore an object of the present invention to provide a stator for an electrical machine whose efficiency is further optimized.

[0006] This is achieved according to claim 1 in that a foam-like / open-pore structure is arranged between a groove base (of the groove) delimiting the respective groove in a radial direction and a wire section of the coil winding closest to this groove base.

[0007] This foam-like structure / material “sucks in” the resin by means of capillary forces, whereby the groove base is also sufficiently wetted with resin.

[0008] Further advantageous embodiments are claimed in the subclaims and explained in more detail below.

[0009] Accordingly, it is further advantageous if the foam-like structure is designed such that a resin material used for encapsulating / encapsulating the coil winding in the slots is sucked in the liquid state from one end face of the base body into the respective slot along the entire length (i.e., an axial extension) or at least over a predominant portion of the entire length of the base body. This ensures that the foam-like structure is designed with the most suitable absorbency / capillary capacity possible.

[0010] It is also advantageous if the foam-like structure is applied to the wire section closest to the slot base before the coil winding is installed in the base body and / or if the foam-like structure is designed to be elastically compressible. This further simplifies assembly.

[0011] Alternatively, the above object is achieved by the subject matter of claim 4, wherein a flow brake is mounted at an axial end of the groove, which closes the spaces between a wire section of the coil winding and a groove base delimiting the respective groove in a radial direction.

[0012] The flow brake simply prevents the liquid resin mass already contained in the groove from accidentally flowing out and allows this resin mass to subsequently harden completely in the groove.

[0013] The invention will now be explained in more detail with reference to the figures. They show: Fig. 1 a sectional view of a stator according to the invention in the region of a slot and a coil winding accommodated therein according to a first embodiment, wherein a foam-like structure at the slot base is clearly visible, Fig. 2 a side view of the entire, in a base body of the stator made of Fig. 1 recorded coil winding, illustrating the foam-like structures attached to wire sections of the coil winding, Fig. 3a to 3c show several sectional views of the coil winding and the foam-like structure in a groove, illustrating the mounting direction ( Fig. 3a) and the compressibility of the structure ( Fig. 3b and Fig. 3c), Fig. 4 another sectional view of the coil winding and the foam-like structure in the groove, where a potting compound can now also be seen, Fig. 5 is a side view of a coil winding accommodated in a base body of a stator according to a second embodiment, wherein flow brakes are now attached to the ends of the wire sections of the coil winding accommodated in the slots, Fig. 6a and Fig. 6b two sectional views of the coil winding according to Fig. 5 during a filling process of the grooves with casting compound, as well as Fig. 7 a perspective view of an overall stator formed according to the first and / or second embodiment.

[0014] The figures are merely schematic and serve solely to clarify the invention. The same elements are designated by the same reference numerals.

[0015] Combined with Fig. 7, reference should first be made to the preferred application of the stator 1 according to the invention. The stator 1 is preferably used in an electrical machine, more preferably a drive motor, of a motor vehicle. The electrical machine, not shown here for the sake of clarity, has, in addition to the Fig. 7, have a substantially annular stator 1, usually on a housing accommodating the stator 1 and a rotor arranged radially inside the stator 1 and rotatably drivable relative to the stator 1.

[0016] In Fig. Figure 7 shows a longitudinal axis 11 of the stator 1, which characterizes the axial, radial, and circumferential directions used herein. This axis is arranged congruent with a rotational axis of the rotor during operation of the electric machine. Accordingly, the axial / axial direction is understood to mean a direction along / parallel to the longitudinal axis 11, the radial / radial direction is understood to mean a direction perpendicular to the longitudinal axis 11, and the circumferential direction / along the circumference is understood to mean a direction along a circular line concentrically encircling the longitudinal axis 11.

[0017] The stator 1 basically has a base body 2 which is also ring-shaped and usually composed of a laminated core, and a coil winding 4 accommodated in this base body 2.

[0018] In the circumferential direction, a plurality of grooves 3 are also usually introduced into the base body 2. The grooves 3 are each open inwardly in the radial direction / open in the base body 2, but are usually closed with a separate closure element 12 during operation.

[0019] In Fig. 1 shows a slot 3 in a cross-section, wherein it can be seen that in the fully assembled state of the stator 1, the coil winding 4 is accommodated in the slot 3 in multiple layers / with several wire sections 6 one above the other.

[0020] According to the invention, a foam-like / open-pore structure 13 in the form of an open-pore material layer is inserted between a wire section 6 closest to a groove base 5 of the groove 3 and the groove base 5. The structure 13, which serves as an impregnation aid, is in contact with the groove base wall or the insulation paper 16.

[0021] In connection with Figure 2, it can be seen that this structure 13 is essentially strip-shaped and preferably extends over the entire length of the groove 3. The structure 13 can already be applied to the coil winding 4 / the wire section 6 closest to the groove base 5 before the coil winding 4 is inserted into the base body 2.

[0022] Assembly is carried out by inserting the coil winding 4 into the base body 2 preferably in the direction indicated by the arrow 14 in Fig. 3a into the groove 3 in the radial direction.

[0023] With the Fig. 3b and Fig. 3c further shows that the structure 13 is in principle designed to be radially compressible. Fig. 3b this is compressed, in Fig. 3c relaxed.

[0024] The structure 13 thus provides an impregnation aid consisting of an open-pore material, such as foam or a fibrous material such as yarn, which is applied to the groove base 5 (either by prior fixation to the wires / wire sections 6 or by application directly into the groove base 5). This material "absorbs" the resin by means of capillary forces, whereby the groove base 5 is sufficiently wetted with resin.

[0025] The function of the impregnation aid is as follows: The foam-like structure 13 is compressed during wave winding assembly and lies in a relaxed state between the groove base 5 and the wire / wire section 6 during trickling. Due to the contact, the impregnation aid comes into early contact with the trickling resin and can suck it into the free space in a defined manner.

[0026] Thus, the foam-like structure 13 is designed such that a resin material used for encapsulating the coil winding 4 in the slots 3 is sucked in the liquid state along the entire length or at least over a predominant part of the entire length of the base body 2 from an end face 7 of the base body 2 into the respective slot 3.

[0027] With the Fig. 5 to 6b further illustrate a flow brake 9. Preferably, the resin / casting compound 15 should be applied from one side only. To prevent leakage on the other side, the flow brake 9 should be attached to the wires / wire sections 6 to stop the resin flow. The flow brake 9 can be, for example, an elastic adhesive strip. The resin flow direction when dripping is Fig. 5 is marked with arrow 17. Arrow 18 describes the rotation of stator 1 (or rotor) during trickling. Angle α indicates the inclination of stator 1 (or rotor) relative to a horizontal plane during trickling.

[0028] The function of the flow brake 9 is as follows: The locally applied material on the wires is applied (e.g. glued, painted, sprayed, etc.) to the (axial) end 8 of the slot 3, whereby the gaps 10 between the wires and wire / wire section 6 to the slot base 5 are locally "sealed". This local sealing prevents the resin from flowing out uncontrollably when dripping and prevents resin from contaminating the outer areas of the stator 1. Also in the Fig. 6a and Fig. 6b, the resin flow direction 17 is marked. In Fig. 6b the resin flow is slowed down by the flow brake 9. List of reference symbols 1 stator 2 basic bodies 3 grooves 4 coil windings 5 Groove base 6 wire section 7 Front side 8 axial end of the groove 9 Flow brake 10 space 11 Longitudinal axis 12 locking element 13 Structure 14 Arrow 15 Casting compound 16 insulation paper 17 Resin flow direction 18 Direction of rotation α angle of inclination

Claims

[1] Stator (1) for an electrical machine, with a substantially annular base body (2) having a plurality of slots (3) distributed along a circumference, and a coil winding (4) arranged at least in sections in the slots (3), characterized by that a foam-like structure (13) is arranged between a groove base (5) delimiting the respective groove (3) in a radial direction and a wire section (6) of the coil winding (4) closest to this groove base (5). [2] Stator (1) according to claim 1, characterized by that the foam-like structure (13) is designed such that a resin material used for encapsulating the coil winding (4) in the grooves (3) is sucked in the liquid state along the entire length or at least over a predominant part of the entire length of the base body (2) from an end face (7) of the base body (2) into the respective groove (3). [3] Stator (1) according to claim 1 or 2, characterized by that the foam-like structure (13) is applied to the wire section (6) closest to the groove base (5) before the coil winding (4) is mounted in the base body (2) and / or is designed to be elastically compressible. [4] Stator (1) for an electrical machine, with a substantially annular base body (2) having a plurality of slots (3) distributed along a circumference, and a coil winding (4) arranged at least partially in the slots (3), characterized by that a flow brake (9) is attached to an axial end (8) of the groove (3), which closes the spaces (10) between a wire section (6) of the coil winding (4) and a groove base (5) delimiting the respective groove (3) in a radial direction.

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