WO2011076321A1

WO2011076321A1 - Method for producing laminated cores for electrical machines

Info

Publication number: WO2011076321A1
Application number: PCT/EP2010/007089
Authority: WO
Inventors: Alexander Krick; Karsten Koellner
Original assignee: Volkswagen Aktiengesellschaft
Priority date: 2009-12-23
Filing date: 2010-11-23
Publication date: 2011-06-30
Also published as: DE102009060170A1

Abstract

The invention relates to a method for producing laminated cores (2) for electrical machines, in particular for producing rotor and/or stator plates, in which a plurality of single sheets (8) are stacked one above the other and are joined by means of adhesion to form a laminated core (2). According to the invention, the single sheets (8) are aligned relative to one another by arrangement on or in a workpiece carrier (9) and subsequently an adhesive (13) is contactlessly applied to a wall surface of the laminated core (2) formed by the end faces of the single sheets (8).

Description

description

Method for producing laminated cores for electrical machines

The invention relates to a method for producing laminated cores for electrical machines, in particular of rotor or stator, in which a plurality of individual sheets are stacked and joined by gluing to form a laminated core.

In the manufacture of electrical machines often formed as rotor or stator packs laminated cores are used, which consist of stacked and interconnected electric plates. The individual sheet metal blanks of the laminated core are usually produced in stamping presses and then stacked. The connection of the sheets with each other can be done by gluing, welding or mechanical

Connecting elements, such as by rivets done.

When welding and riveting the sheets, it proves to be disadvantageous that an electrical contact between the individual sheets is produced. This electrical contact increases, especially at high frequencies, the losses in the electric motor during operation.

The gluing of the sheets has the advantage that the arranged between the sheets of adhesive no electrical contact between the individual sheets of a

Laminated cores. As a result, the efficiency of the electric motor at the same

Package size improved or a smaller motor can be used to achieve the same output power.

A known method for the production of electric motors with a high power density is that the sheets are provided with a special coating, a so-called baked enamel, so that the sheets forming the laminated core are later baked together by heating in an oven. As a result, a better mechanical strength and possibly a reduction of the noise is achieved by vibrations.

In the baked enamel process, it proves to be disadvantageous that the stacked sheets for up to two hours at temperatures between 90 ° C and 200 ° C in the oven must be baked to the desired strength of the adhesive bond between the individual sheets or the mechanical strength of the laminated core

to be able to guarantee. In addition to the high production times, ^' the large investment for the required equipment and the low energy efficiency of the

Procedure as particularly disadvantageous.

From EP 1 833 145 A2, a method of the initially mentioned type is already known in which individual sheets are punched out of a starting material designed as a strip by means of a stamping press. Before punching, an adhesive is applied in points to the top and / or bottom of the strip. Here, the adhesive can be applied on the one hand before the punching tool within the press with an external equipment or on the other hand in the punching tool itself with an integrated system. After application of the adhesive dots on the strip, the individual sheets are punched out of the strip and the laminated core is arranged one above the other in the die of the punching tool or in a slot associated with the die and joined together. A brake associated with the tray prevents the individual sheets from falling down through the tray.

Here, the high investment costs for a punch press with an integrated system for applying the adhesive and a die with a shaft and integrated brake prove to be particularly disadvantageous. Furthermore, it can thereby, that the punching of the

Individual sheets only after the application of the adhesive points, come to the fact that the stamp touches the adhesive dots and they are destroyed, so that a reliable connection of the individual sheets is not guaranteed to each other. Another disadvantage is the contamination of the stamp or the die by the contacted during the punching process adhesive points and an associated increased cleaning and

Maintenance, resulting in undesirable downtime of the punch press.

Other methods for producing laminated cores by gluing are known from DE 35 03 019 A1 and DE 32 44 823 A1.

The invention has for its object to provide an energy-efficient and / or process-safe method for the production of laminated cores.

This object is achieved by a method according to the features of independent claim 1. The dependent claims are particularly appropriate

Embodiments or developments of the invention. In the method according to the invention for producing laminated cores for electrical machines, a plurality of individual sheets are stacked on top of one another and joined by gluing to form a laminated core. According to the invention, in the method for producing laminated cores for electrical machines, it is provided that the individual sheets are arranged on or in one piece by the arrangement

Workpiece carrier are aligned relative to each other and then an adhesive is applied contactlessly on a formed by the end faces of the individual sheets wall surface of the laminated core, in particular sprayed, applied, sprayed,

dripped or the like.

By the contactless application of the adhesive, preferably applied as a spray, a possibility is created, the adhesive finely dosed and evenly distributed on the wall surface of the laminated core. Due to the capillary effect, the adhesive passes from the end faces of the individual sheets into the gaps between the individual sheets, which wets each other

oppositely arranged surfaces of the respective adjacent individual sheets and glued the individual sheets so to a laminated core. Furthermore, an electrical contact between the individual sheets is prevented by the adhesive arranged between the individual sheets, so that relatively small electric motors with high power density can be produced by means of the method according to the invention. By gluing the individual sheets on a workpiece carrier following the punching process contamination of the individual sheets producing punching press is effectively prevented. In the method according to the invention, low cycle times can be achieved. Furthermore, with appropriate

Execution also high investment costs can be avoided.

A particularly advantageous embodiment of the method according to the invention is provided in that the individual sheets are arranged in and / or on the workpiece carrier such that openings arranged in the individual sheets form an opening in the laminated core. If the laminated core is to be used as a rotor core of an internal electric motor, an opening can serve to receive a shaft, and if the laminated core is to be used as a stator core of an internal rotor electric motor, the rotor can be arranged in the opening. Depending on the specific configuration of the electric motor, one or more further openings, in particular for

Influencing the course of the magnetic field and / or the magnetic flux density, be provided. The openings may in particular have different geometric shapes, layers and / or sizes. If the laminated core is a rotor core, it proves to be particularly useful that the individual sheets on a in a group of superposed openings of the

stacked individual sheets engaging centering mandrel of the workpiece carrier are arranged. As a result, the individual sheets on the one hand exactly aligned relative to each other and on the other hand is created by the engaging in the openings centering a possibility to ensure the accessibility of the outer wall surface of the laminated core for spraying the adhesive. The bonding and insulation of the

Individual sheets of the rotor advantageously takes place in a region of the rotor facing the stator, so that the losses of the electric motor can be kept low.

In particular, in the production of a stator core, on the other hand, it proves to be particularly expedient if the individual sheets in such a trained as a container

Workpiece carriers are arranged so that an outer wall surface of the laminated core at least partially rests against a container wall. As a result, the alignment of the individual sheets is effected by the voltage applied to the container wall outer wall surface, so that then the adhesive to an opening in the laminated core limiting inner wall surface of

Laminated packages applied, in particular sprayed, can be. The bonding and

Insulation of the individual sheets of the stator takes place in a region facing the rotor, so that the losses of the electric motor can be kept low.

Another particularly advantageous development of the method according to the invention provides that the individual sheets arranged in or on the tool carrier are subjected to a pressure compressing the individual sheets before and / or after the adhesive is sprayed onto the wall surface of the laminated core. The pressure can ensure a uniform curing of the adhesive and a uniform package strength.

Furthermore, by the pressure acting on the individual sheets pressure of the distance

be reduced to each other lying individual sheets. The smaller the distance of the individual sheets from one another, the greater is the existing capillary pressure and the further the adhesive penetrates into the gap between the individual sheets.

A particularly economical method is also provided in that the individual sheets are produced by means of a stamping press from a starting material, which is the punch press is supplied as a continuous strip, in particular as a coil.

The economy of the method according to the invention is further increased, characterized in that the individual sheets immediately after a punching operation in or on the Workpiece carriers are arranged, wherein the individual sheets remain in or on the workpiece carrier during the subsequent method steps. As a result, additional manipulations of the individual sheets or the laminated cores are not required. The individual sheets may remain in the respective workpiece carrier after the punching operation, during non-contact application, in particular spraying of the adhesive and during the pressurization and until the end of the curing process. The

Arrangement of the individual sheets in the workpiece carrier can preferably be carried out ready in the punch press, so that the individual sheets are transported together with the workpiece carrier from the punch press. In this way, eliminates an additional separate process step in which the individual sheets are removed individually from the punch press. Of the

Workpiece carrier can be moved preferably and particularly advantageous by a conveyor belt.

Furthermore, it proves to be particularly useful if one for spraying the

Adhesive provided metering device and to be sprayed wall surface of the

Sheet metal packages are moved relative to each other during the spraying process. The

Metering device may in particular a spray gun and / or one or more

Include spray nozzles. The metering device can be handled manually or automatically by a robot or a manipulating device.

Due to the relative movement, the distribution of the adhesive and the wetting of the

Wall surface made very effective and finely dosed. A pollution of the

Workpiece carrier by sprayed adhesive or on the wall surface of the

Sheet metal packs running down adhesive can be minimized. Here, on the one hand, the metering device can be moved relative to the stationarily arranged laminated core and

On the other hand, it is possible that the laminated core arranged relative to the stationary

Dosing is moved.

In the production of stator packets, it proves to be particularly advantageous that the metering device for spraying the adhesive is at least partially introduced into at least one of the openings of the laminated core. This allows the distance of the

Metering be optimized by the sprayed to the inner wall of the laminated core.

A contamination of the individual sheets producing punching press by the contact of the punch with the adhesive dots, as described above, can be prevented in the inventive method, characterized in that the spraying of the adhesive on the one hand only in the Connection to the punching process and on the other hand in the area of the end faces of the individual sheets done. It can be used a commercial punching press, whereby the

Investment costs for a punch press can be saved with an integrated adhesive application system. By spraying the adhesive in the region of the end face, it is also impossible for a clamping device acting on the individual sheets to come into contact with the adhesive under pressure. Furthermore, the use of a cold-curing adhesive provides an energy-efficient, process-reliable method by which low cycle times can be ensured. The glue can be one

Reaction adhesive, in particular, the adhesive may be one-component,

The invention can be implemented in numerous embodiments. With reference to the single figure, a preferred advantageous embodiment of the method according to the invention is described below.

The figure shows a schematic representation of a manufacturing device 1 for the production of metal sheets 2 for electrical machines, in particular rotor and / or stator packs. A arranged on a coil 3 starting material 4, in particular electrical steel is fed to a punch press 5 continuously. In this embodiment, the starting material 4 is strip-shaped and is unwound from the coil 3. By means of a stamping tool 6 arranged on a punch 6 are from the supplied strip-shaped starting material 4th

Individual sheets 8 punched out and stacked in a container designed as a container and arranged in the punch press 5 workpiece carrier 9. In the punching process, not shown openings are punched out of the individual sheets 8 in the figure, wherein the

Individual sheets 8 are aligned by the workpiece carrier 9 such that the openings of the individual sheets 8 are arranged one above the other, so that these together a

Make opening in the laminated core 2.

If in the workpiece carrier 9, the desired or required number of

Individual plates 8 is arranged, the workpiece carrier 9 is transported together with the individual sheets 8 by a conveyor belt 10 from the punch press 5. Outside the punch press 5, a metering device 11 formed as a spray gun is introduced into the opening of the laminated core 2 arranged in the workpiece carrier 9 (directional arrow 12). Through the spray gun, a cold-curing adhesive 13 on a through the front sides of the

Single sheets sprayed 8 formed wall surface. In the described embodiment, this wall surface is formed by an opening in the laminated core 2 limiting inner wall. The adhesive 13 passes through the capillary effect in a gap between the Single sheets 8 and wets the surfaces of the respective adjacent individual sheets 8 at least partially.

After spraying the adhesive 13, the metering device 1 1 again from the

Opening out of the laminated core 2 moved out and the individual sheets 8 are acted upon by a clamping device 14 with a compressive pressure on the individual sheets 15. During the pressurization of at least partially arranged between the individual sheets 8 adhesive 13 hardens. Subsequently, the joined laminated cores 2 are removed from the workpiece carrier 9. In an advantageous manner, the workpiece carriers 9 arranged on the conveyor belt 10 are moved continuously or intermittently during the method according to the invention. In order to facilitate a cleaning of, for example, by dripping adhesive 13 dirty workpiece carrier 9, these can one

adhesion-reducing coating, for example made of Teflon or silicone.

Accordingly, the conveyor belt can be coated to reduce adhesion.

LIST OF REFERENCE NUMBERS

manufacturing facility

laminated core

coil

starting material

punch press

stamp

punching tool

Single sheet

pallet holder

conveyor belt

metering

arrow

adhesive

tensioning device

print

Claims

claims

1 . Method for producing laminated cores (2) for electrical machines, in which. a plurality of individual sheets (8) stacked on top of one another and joined by gluing to form a laminated core (2), characterized in that the individual sheets (8) pass through the sheet metal

Arrangement on or in a workpiece carrier (9) are aligned relative to each other and then an adhesive (13) contactless on a by the end faces of the individual sheets (8) formed wall surface of the laminated core (2) is applied.

2. The method according to claim 1, characterized in that the individual sheets (8) are arranged in or on the workpiece carrier (9) that in the individual sheets (8) arranged openings form an opening in the laminated core (2).

3. The method according to claim 2, characterized in that the individual sheets (8) on a in the openings of the individual sheets (8) engaging centering of the

Workpiece carrier (9) are arranged.

4. The method according to at least one of the preceding claims, characterized

in that the individual sheets (8) are arranged in a workpiece carrier (9) designed as a container in such a way that an outer wall surface of the laminated core bears at least partially against a container wall.

5. The method according to claim 2, characterized in that the adhesive (13) on an opening in the laminated core (2) limiting inner wall surface of the laminated core (2) is applied.

6. The method according to at least one of the preceding claims, characterized

characterized in that arranged in or on the workpiece carrier (9)

Individual sheets (8) before and / or after the spraying of the adhesive (13) on the wall surface of the laminated core (2) with the individual sheets (8) compressive pressure (15) are acted upon.

7. The method according to at least one of the preceding claims, characterized

in that the individual sheets (8) are produced by means of a punch press (5) from a starting material (4) which is fed to the punch press (5) as a continuous strip.

8. The method according to claim 7, characterized in that the continuous strip of a coil (3) is unwound.

9. The method according to at least one of the preceding claims, characterized

characterized in that the individual sheets (8) immediately following a

Punching be arranged in or on the workpiece carrier (9), wherein the

Individual sheets (8) during the subsequent process steps in or on the

Workpiece carrier (9) remain.

10. The method according to claim 9, characterized in that the individual sheets in the

Punching press (5) are arranged and the arranged individual sheets (8) are transported together with the workpiece carrier (9) from the punch press (5).

1 1. A method according to claim 9 or 10, characterized in that the workpiece carrier (9) by a conveyor belt (10) is moved.

12. The method according to at least one of the preceding claims, characterized

characterized in that one for spraying the adhesive (13) provided

Dosing (1 1) and to be sprayed wall surface of the laminated core (2) are moved relative to each other during the spraying process.

13. The method according to claim 10, characterized in that the metering device (1 1) comprises a spray gun and / or one or more spray nozzles.

14. The method according to at least one of the preceding claims, characterized

characterized in that the metering device (1) for spraying the adhesive (13) is at least partially inserted into the opening of the laminated core (2).

15. The method according to at least one of the preceding claims, characterized

in that the laminated core (2) is a rotor core or a stator core of an electrical machine.