DE102021115421B3 - Method and device for producing a stator device for an electric machine, in particular for a drive machine of an electric vehicle - Google Patents

Abstract

Method for producing a stator device (1) for an electrical machine, in particular for a drive motor of an electric vehicle, the stator device (1) having a laminated core device (2) and receiving grooves (12) running in the axial direction for receiving winding elements and a rotor receiving space (22) for Accommodating a rotor that can rotate relative to the stator device (1) and a sealing jacket structure (4) for coolant-tight delimitation of the receiving grooves (12) from the rotor receiving space (22), the laminated core device (2) being arranged in a tool device (3) and the tool device (3) comprises core elements (13) and cavities (23) for forming a groove lining (5) for the receiving grooves (12) and for forming the sealing jacket structure (4) are specifically formed between the laminated core device (2) and the core elements (13). and wherein a plastic material under pressure and temperature at an axial stir is introduced on the side of the tool device (3) and is distributed from there in a star-like pattern radially outwards to the sprue points (16) and is deflected in an axial direction in the region of the sprue points (16), and the sprue points (16) each have at least one nozzle-like cross-sectional constriction (26) assigned.

Description

The present invention relates to a method for producing a stator device for an electrical machine and in particular for a drive unit of an electric vehicle and preferably an electric car. The invention also relates to a device for producing a stator device using such a method.

Directly cooled stator devices are often used for drive machines, which usually have a laminated core device and receiving grooves running in the axial direction for receiving winding elements and a rotor receiving space for receiving a rotor that can rotate relative to the stator device, as well as a sealing jacket structure for coolant-tight delimitation of the receiving grooves from the rotor receiving space. Due to the sealing jacket structure, the stator device can be cooled during operation of the electrical machine without coolant reaching the rotor.

In the prior art, stator devices have become known in which the sealing jacket structure is provided by what is known as a can. The can and the rotor receiving space are designed to fit one another and are then pressed together.

In addition, in the case of correspondingly small or compact motors, it has become known to produce the sealing jacket structure by attaching a plastic material to the laminated core device. For example, the laminated core device is placed in a tool device and overmoulded with the plastic material. This offers an overall economical manufacture of the stator device.

the DE 197 46 605A1 describes a method for insulating a stator of an electronically commutated DC motor. The stator is placed in a closable mold with laterally extendable jaws. In the closed state, the mold can enclose the outer contours of the stator, including a printed circuit board, at a distance. After closing the mold, a polyamide-based thermoplastic hot-melt adhesive is injected under pressure. After opening the mold, the overmoulded stator is removed.

From the DE 100 26 467 A1 a spindle motor for a hard disk drive is known in which either a laminated core or the entire stator consisting of laminated core and windings is surrounded by a centering jacket made of plastic. The centering sleeve is applied using an injection molding process. The centering shell can be centered on a stationary shaft and/or on an outer or inner ring, which belongs to one or more rolling body collectives. This should result in highly precise, concentric and exact enveloping, supporting and positioning surfaces on which the stator can be placed or centered.

the U.S. Patent No. 4,015,154 shows a method for producing an electric motor with a laminated stator core with slots and stator teeth for accommodating a winding. The laminated core of the stator is inserted into a hollow-cylindrical laminated core. Then the stator core and the hollow-cylindrical core are placed in a mold and cast with a resin.

From the CN 2 01 918 853 U an injection mold for producing a stator core of an electric motor is known. In this case, an injector main body and an injection channel system with a large number of channels are provided.

However, due to the dimensions and performance and quality requirements necessary for driving machines of electric vehicles, the known approaches for attaching the plastic material to a laminated core device are still very much in need of improvement. It has been shown that it is sometimes very difficult to distribute the plastic material in a targeted manner and as optimally as possible in the tool device. This results in undesirable effects on the tightness and the quality of the machine as a whole.

In contrast, it is the object of the present invention to provide an improved possibility for producing a stator device with direct cooling. In particular, the solution should also be suitable for series production of drive units for electric vehicles.

This object is achieved by a method having the features of claim 1. A device according to the invention is the subject of claim 17. Preferred developments of the invention are the subject of the dependent claims. Further advantages and features of the present invention result from the general description and the description of the exemplary embodiment.

According to the invention, the laminated core device is arranged in a tool device. In particular, the tool device includes core elements. Cavities for forming a groove lining for the receiving grooves and/or a sealing jacket structure are made in a targeted manner between the laminated core device and the core elements educated. A plastic material is introduced under pressure and temperature, in particular on an axial end face of the tool device, preferably radially in the middle (via a sprue plate). From there, the plastic material is distributed in a star-like pattern radially outwards to the sprue points. In the area of the sprue points, the plastic material is deflected in an axial direction. At least one nozzle-like cross-sectional constriction (running in the axial direction) is assigned to each of the sprue points.

Particularly preferably, the plastic material is fed to at least one distributor geometry downstream of the cross-sectional constrictions. In particular, the distributor geometry bears against (an axial end face) the laminated core device at least in sections. In this way, in particular, channel-like distribution channels are provided between the distribution geometry and the laminated core device. In particular, the plastic material reached the cavities via the distribution channels and fills them up, in particular so that the groove lining and/or the sealing jacket structure are formed.

The method according to the invention offers many advantages. The targeted flow guidance of the plastic material in the tool device offers a considerable advantage. The targeted deflection and the nozzle-like narrowing of the cross-section at the sprue points and the front-side distributor geometry are particularly advantageous. This enables a particularly high component quality and reliable tightness as well as particularly economical production. A particular advantage of the invention is that a targeted and almost ideal mold filling behavior can be implemented without much effort.

As a result, overall shorter cycle times can be achieved while at the same time avoiding air pockets in the encapsulation.

In all of the configurations, it is preferred that the groove lining and/or the sealing jacket structure are formed by means of a transfer molding process (so-called transfer molding). In particular, the device, for example the tool device, is suitable and designed for a transfer molding process. Another suitable primary shaping method is also possible, for example a casting method and preferably an injection molding method.

In particular, the tool device comprises at least one sprue plate for distributing the plastic material in a star-like manner. In particular, the sprue plate has at least one sprue point for each receiving groove provided. In particular, the sprue plate has at least one feed opening for the plastic material on the end face and preferably radially in the middle.

In particular, the sprue plate has sprue channels which are suitable and designed for the star-like distribution of the plastic material. In particular, a common sprue channel is provided for at least two sprue points. It is also possible that at least one sprue channel is provided for each sprue point.

The tool device preferably comprises at least one mold plate. In particular, the distribution geometry is formed in or on the mold plate. In particular, the mold plate provides at least part of the cross-sectional constriction. In particular, the mold plate is flow-connected to the sprue plate. In particular, the mold plate is arranged downstream of the sprue plate. In particular, the mold plate and the sprue plate each represent separate tool parts. In particular, the mold plate and the sprue plate are coupled to one another adjacent to one another axially or at the front.

It is possible and advantageous that the mold plate and the sprue plate each provide a section of the cross-sectional constriction. In particular, the mold plate has a narrower cross-sectional constriction than the sprue plate. It is also possible that only the sprue plate or only the mold plate is equipped with cross-sectional constrictions.

It is preferred and advantageous that the distributor geometry has at least one distributor channel for each gate point and/or for each receiving groove. In particular, the distribution channel runs in the radial direction. In particular, the distribution channel extends up to the cavity for the sealing jacket structure. In particular, the distribution channel provides a flow path that is as direct as possible to the sealing jacket structure, so that the fastest possible filling with lower pressures is possible. In particular, the distributor channel is provided by targeted elevations and/or depressions in the distributor geometry.

In particular, at least two and preferably at least three (or four or more) distributor channels of the distributor geometry are assigned to a gate. In particular, the at least two distribution channels, which are each assigned to a gate point, run between two adjacent receiving grooves. In particular, from the at least two distribution channels, each of which is assigned to a gate point, in particular at least one in each case one of the adjacent receiving grooves.

In particular, the distribution channels are flow-connected at least partially by transverse channels running (in the circumferential direction). In particular, the distributor geometry includes a large number of transverse channels. In particular, the transverse channels allow the plastic material to flow from one distributor channel into another distributor channel. In particular, those distributor channels are connected to at least one transverse channel which emanate from a common gate point.

In particular, all (or at least the majority or at least 75% or at least 90%) of the distribution channels converge at least indirectly in the cavity for the sealing jacket structure. This enables particularly good mold filling behavior even with short cycle times.

In all configurations, it is particularly preferred and advantageous that the plastic material is introduced into the laminated core device from only one axial end face of the tool device. In particular, it is provided that the plastic material is guided from only one axial end face of the laminated core device to the opposite axial end face of the laminated core device. This reliably avoids the occurrence of undesired butt joints or weld seams that weaken the stability, which represent structural weak points and could give way, for example, due to the pressure of the cooling medium.

The gating points are preferably arranged radially further outwards in relation to the sealing jacket structure and/or in relation to the receiving grooves. In particular, the cross-sectional constrictions are also arranged radially further outward than the receiving grooves and/or the sealing jacket structure. In particular, the sprue points are arranged on a common peripheral line. In particular, the cross-sectional constrictions are arranged on a common circumferential line. In particular, the cross-sectional constrictions are arranged at a common radial height with the gate points. In particular, the cross-sectional constrictions are located axially behind the sprue points, so that there is no flow deflection, particularly on the way from a sprue point to the associated cross-sectional constriction.

At least one duromer is particularly preferably used as the plastic material. Other plastic materials suitable for the method presented here and preferably for a transfer molding method are also possible.

It is possible and advantageous for the receiving grooves to each be equipped with at least one surface insulation. In particular, the surface insulation extends between the core element and the slot lining. It is also possible for the surface insulation to be arranged in the receiving slots only after the slot lining has been shaped.

In all configurations, it is preferred and advantageous that the winding elements are only arranged in the receiving slots after the slot lining has been formed. The invention presented here offers many advantages in the production of such a stator device.

The device according to the invention is used to produce a stator device. In particular, the device is suitable and designed to produce the stator device using the method described above. In particular, the device comprises the tool device described above. The device can have other devices that are necessary or advantageous for implementation. Such a device enables, for example, series production with high quality.

In the context of the present invention, a laminated core device is understood to mean both a stacked laminated core and a one-piece stator body manufactured, for example, from a solid block. In particular, cooling fluid can flow through at least the receiving grooves. In particular, the receiving grooves are designed to be coolant-tight with respect to the rotor receiving space.

In particular, the plastic material in the area of the distributor geometry, in particular in the distribution channels, is pressed essentially from radially outside to radially inside. In particular, the plastic material is then pressed through the cavities in the axial direction. The narrowing of the cross section is, in particular, of conical design. The narrowing of the cross section can also be referred to as a sprue cone.

In particular, the distributor geometry includes elevations and/or depressions. In particular, the elevations rest at least partially on the laminated core device. In particular, the distribution channels are provided in the area of the depressions and/or outside of the elevations. In particular, the cross section of the distribution channel is adapted by dimensioning the elevation and/or depression in order to achieve the desired mold filling behavior.

In particular, the tool device comprises at least one core element for forming the receiving grooves, for example a groove core. In particular, at least one core element is provided for each receiving groove. The tool device comprises at least one core element for shaping the sealing jacket structure, for example a tool core adapted to the rotor receiving space.

In particular, at least one cavity is provided between a respective core element for forming a slot lining and the laminated core device in the area of the receiving slot. In particular, at least one cavity is provided between the core element for shaping the sealing jacket structure and the laminated core device in the area of the rotor receiving space.

Further advantages and features of the present invention result from the exemplary embodiments which are explained below with reference to the enclosed figures.

• 1 eine stark schematisierte Darstellung einer erfindungsgemäßen Vorrichtung zur Herstellung einer Statoreinrichtung nach dem erfindungsgemäßen Verfahren;
• 2 eine rein schematische Detaildarstellung der Vorrichtung nach 1 in einer quer geschnittenen Vorderansicht mit einer ausschnittsweisen Vergrößerung in einer längs geschnittenen Seitenansicht; und
• 3 eine weitere Detaildarstellung der Vorrichtung nach 1 in einer quer geschnittenen Vorderansicht.

In the figures show:

• 1 a highly schematic representation of a device according to the invention for producing a stator device according to the method according to the invention;
• 2 a purely schematic detailed representation of the device 1 in a cross-sectional front view with a partial enlargement in a longitudinally sectional side view; and
• 3 a further detailed view of the device 1 in a cross-sectional front view.

the 1 shows a device 10 according to the invention for producing a stator device 1 according to the method according to the invention. The stator device 1 is accommodated in a tool device 3 here. The stator device 1 is provided here for a drive machine of an electric vehicle. To better illustrate the arrangement of the stator device 1 in the tool device 3, the latter is shown here partially transparently.

The stator device 1 here comprises a laminated core device 2, receiving grooves 12 running in the axial direction for receiving winding elements, not shown here, and a rotor receiving space 22 for receiving a rotor which can rotate relative to the stator device 1 and is also not shown here. In addition, the stator device 1 here includes a sealing jacket structure 4 for coolant-tight delimitation of the receiving grooves 12 from the rotor receiving space 22. The receiving grooves 12 and the rotor receiving space 22 are not visible inside the laminated core device 2 and are indicated here by dashed lines.

The tool device 3 here comprises a sprue plate 6 and a mold plate 7 as well as an end plate 43 and a central part 33 arranged between the end plate 43 and the mold plate 7. The end plate 43 can also have a distributor geometry 17, as is described below for the mold plate 7 .

When the laminated core device 2 is arranged as intended in the tool device 3 , core elements 13 are introduced into the receiving grooves 12 and the rotor receiving space 22 . This results in cavities 23 between the laminated core device 2 and the core elements 13, which are filled with the plastic material to form the slot lining 5 and the sealing jacket structure 4. A transfer molding process is used for this purpose.

The method for forming the groove lining 5 for the receiving grooves 12 and the sealing shell structure 4 is described below with reference to FIG 1 until 3 described in more detail.

A transfer molding process is used for this purpose. The plastic material is, for example, a duromer. The flow paths of the plastic material in the tool device 3 are sketched here very schematically by arrows. The plastic material is introduced radially centrally into the sprue plate 6 under pressure and temperature on an axial end face of the tool device 3 . From there, the plastic material on in the 2 Sprue channels 36 shown are distributed in a star-like pattern radially outward to the sprue points 16 .

In the area of the sprue points 16, the plastic material is deflected in an axial direction. At least one nozzle-like cross-sectional constriction 26 (see Fig 2 ) assigned. The cross-sectional constriction 26 is partially formed in the sprue plate 6 and partially in the mold plate 7 here.

The plastic material is guided to a distributor geometry 17 of the mold plate 7 downstream of the cross-sectional constrictions 26 . The distributor geometry 17 bears in sections on an axial end face of the laminated core device 2 so that distributor channels 27 are provided between the distributor geometry 17 and the laminated core device 2 . The plastic material reaches the cavities 23 via the distribution channels, so that these are filled and the groove lining 5 and the sealing jacket structure are formed.

In the 3 the end face of the laminated core device 2 is shown without the sprue plate 6 and without the mold plate 7 . As a result, the plastic material that has already been distributed can be clearly seen here. In addition, in the 3 the flows of the plastic material along the distribution channels 27 are outlined by arrows. In one embodiment, it can be provided that one or more transverse channels 37 extend between two or more adjacent distribution channels 27 (outlined here by dashed arrows).

To provide the distributor channels 27, the distributor geometry 17 is equipped with appropriate elevations and depressions, as is the case, for example, in FIG 2 is shown.

A surface insulation 32 for the receiving grooves 12 is in the 3 sketched.

The invention addresses the problem that only a very limited time window is available for the distribution of the plastic material in the laminated core device 2 before the plastic material cools down to a critical level. With the invention, as much plastic material as possible can be distributed as evenly and reliably as possible in a short time.

The invention presented here offers an optimized gating concept that enables a particularly homogeneous mold filling. In particular, the plastic material (so-called molding compound) is divided into sprue channels 36 for two receiving grooves 12 in the sprue plate 6 in the first step. Then, for example, there is a further branching to the two channels. This enables particularly low pressure losses. This is followed by the cross-sectional constrictions 26 (so-called sprue cones), which contribute to the pressure increase and increase in the shear rate. These are designed here, for example, as continuous conical channels through both plates 6, 7 (the narrowing of the cross section 26 can also lead through only one tool plate or through several tool plates). The material is then distributed here by a distributor geometry 17 specially adapted for this purpose (also referred to as end disk geometry), which enables the most direct possible flow paths to the cavity 23 for the sealing jacket structure 4 and thus offers particularly fast filling with lower pressures.

Reference List

1

stator device

2

lamination stack setup

3

tool setup

4

sealing jacket structure

5

slot lining

6

sprue plate

7

mold plate

10

contraption

13

core element

12

receiving groove

16

gate point

17

manifold geometry

22

rotor receiving space

23

cavity

26

constriction

27

distribution channel

32

surface isolation

33

center part

36

runner

37

cross channel

43

end plate

Claims (17)

Method for producing a stator device (1) for an electrical machine, wherein the stator device (1) has a laminated core device (2) and receiving grooves (12) running in the axial direction for receiving winding elements and a rotor receiving space (22) for receiving a rotor relative to the stator device (1 ) rotatable rotor and a sealing jacket structure (4) for the coolant-tight delimitation of the receiving grooves (12) from the rotor receiving space (22), the laminated core device (2) being arranged in a tool device (3) and the tool device (3) having core elements (13) and wherein between the laminated core device (2) and the core elements (13) cavities (23) are formed in a targeted manner for forming a groove lining (5) for the receiving grooves (12) and for forming the sealing jacket structure (4), and wherein a plastic material is pressurized and Temperature is introduced at an axial end face of the tool device (3) and from there t is distributed in a star-like pattern radially outwards to the sprue points (16) and deflected in an axial direction in the region of the sprue points (16), and at least one nozzle-like cross-sectional constriction (26) is assigned to each sprue point (16). Method according to the preceding claim, in which the plastic material is guided downstream of the cross-sectional constrictions (26) to a distributor geometry (17), the distributor geometry (17) adjoining at least in sections the laminated core device (2), so that channel-like distribution channels (27) are provided between the distributor geometry (17) and the laminated core device (2), with the plastic material reaching the cavities (23) via the distribution channels (27) and filling them, so that the Groove lining (5) and the sealing jacket structure (4) are formed. Method according to one of the preceding claims, wherein the groove lining (5) and the sealing shell structure (4) are formed by means of a transfer molding process. Method according to one of the preceding claims, wherein the tool device (3) comprises at least one sprue plate (6) for distributing the plastic material in a star-like manner and wherein the sprue plate (6) has at least one sprue point (16) for each receiving groove (12) provided. Method according to the preceding claim, wherein the sprue plate (6) has sprue channels (36) for distributing the plastic material in a star-like manner and wherein a common sprue channel (36) is provided for at least two sprue points (16). Method according to one of the preceding claims, wherein the tool device (3) comprises at least one mold plate (7) in which the distributor geometry (17) is formed and wherein the mold plate (7) provides at least part of the cross-sectional constriction (26). Method according to the preceding claim and after claim 3 , wherein the mold plate (7) and the sprue plate (6) each provide a portion of the cross-sectional constriction (26). Method according to one of the preceding claims, wherein the distributor geometry (17) has at least one distributor channel (27) running in the radial direction for each gate point (16) and/or for each receiving groove (12). Method according to one of the preceding claims, wherein at least two distributor channels (27) of the distributor geometry (17) are assigned to a gate point (16) and wherein the at least two distributor channels (27), which are each assigned to a gate point (16), between two adjacent ones Receiving grooves (12) run. Method according to the preceding claim, in which the distribution channels (27) are at least partially flow-connected by transverse channels (37) running in the circumferential direction. Method according to one of the two preceding claims, in which all distribution channels (27) converge at least indirectly in the cavity for the sealing jacket structure. Method according to one of the preceding claims, in which the plastic material is introduced into the laminated core device (2) from only one axial end face of the tool device (3). Method according to one of the preceding claims, wherein the gating points (16) are arranged radially further outwards in relation to the sealing jacket structure (4) and/or in relation to the receiving grooves (12). Method according to one of the preceding claims, wherein at least one duromer is used as the plastic material. Method according to one of the preceding claims, in which the receiving slots (12) are each equipped with at least one surface insulation (32) which extends between the core element (13) and the slot lining (5). Method according to one of the preceding claims, in which the winding elements are only arranged in the receiving slots (12) after the slot lining (5) has been shaped. Device (10) for producing a stator device (1) by a method according to one of the preceding claims.

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