Method for stacking sheet metal parts made from an electrical steel strip or sheet to form lamination stacks

Patent metadata

Field	Value
Publication number	US-11745247-B2
Application number	US-202117909127-A
Country	US
Kind code	B2
Filing date	Mar 2, 2021
Priority date	Mar 2, 2020
Publication date	Sep 5, 2023
Grant date	Sep 5, 2023

Abstract

A method for stacking sheet metal parts composed of an electrical steel strip or sheet in order to form lamination stacks, each with a stack height within a tolerance range from a predetermined desired stack height, including stacking the sheet metal parts, which have a hot-melt adhesive varnish layer on at least one flat side, preheating the hot-melt adhesive varnish layers and putting the hot-melt adhesive varnish layers under pressure, then determining the stack height of the individual lamination stacks and adjusting the stack height if necessary, and then finally heating the hot-melt adhesive varnish layers.

First claim

The invention claimed is:

1. A method for stacking sheet metal parts made from an electrical steel strip or sheet in order to form lamination stacks each having a stack height within a tolerance range from a predetermined desired stack height, comprising:
stacking a plurality of sheet metal parts, which have a hot-melt adhesive varnish layer on at least one flat side of each of the plurality of sheet metal parts, onto one another, defining stacked sheet metal parts,
preheating the hot-melt adhesive varnish layers of the stacked sheet metal parts to a first temperature, which is above a glass transition temperature of the hot-melt adhesive varnish and below a baking temperature of the hot-melt adhesive varnish, and in this preheated state, putting the hot-melt adhesive varnish layers of the stacked sheet metal parts under pressure, then
determining the stack height of the individual lamination stacks composed of the stacked sheet metal parts using a measuring procedure and when this determined stack height falls below the tolerance range, placing at least one additional sheet metal part onto an end surface of the relevant lamination stack so as to adjust the stack height to a height within the tolerance range from the predetermined desired stack height, and then
finally heating the hot-melt adhesive varnish layers of each lamination stack to a second temperature, which is greater than or equal to the baking temperature of the hot-melt adhesive varnish, and as a result, the sheet metal parts of each lamination stack are baked onto one another by the hot-melt adhesive varnish layers.

2. The method according to claim 1 , wherein at least one sheet metal part is placed onto the hot-melt adhesive varnish layer on the lamination stack and the at least one sheet metal part is optionally heated before the at least one sheet metal part is placed onto the lamination stack and the at least one sheet metal part is optionally placed onto the hot-melt adhesive varnish layer under pressure.

3. The method according to claim 1 , wherein the first temperature is in a range from 90° C. to 150° C., and/or the second temperature is in a range from 180° C. to 250° C.

4. The method according to claim 1 , wherein the determining of the stack height and/or the placing at least one additional sheet metal part onto the end surface of the relevant lamination stack so as to adjust the stack height is/are carried out in the preheated state of the hot-melt adhesive varnish layers.

5. The method according to claim 1 , wherein the heating of the hot-melt adhesive varnish layers to the first temperature takes place in a stacking unit, which follows a stamping tool that exerts pressure on the hot-melt adhesive varnish layers in the stacking unit.

6. The method according to claim 1 , wherein the preheating of the hot-melt adhesive varnish layers to the first temperature takes place in a first furnace into which the lamination stacks composed of the stacked sheet metal parts are conveyed.

7. The method according to claim 6 , wherein the adjustment of the stack height takes place in a stack-controlling device and/or the baking of the sheet metal parts takes place in a second furnace.

8. The method according to claim 1 , wherein all of the lamination stacks are placed under the same high pressure and/or the pressure is in the range from 2 to 10 N/mm 2 .

9. The method according to claim 1 , wherein a thickness of each sheet metal part is between 0.1 and 0.5 mm and/or a thickness of the hot-melt adhesive varnish layer of each sheet metal part is between 2 and 12 μm.

10. The method according to claim 1 , wherein each lamination stack has more than 100 sheet metal parts.

11. The method according to claim 1 , wherein in the event that the determined stack height of the lamination stack exceeds the desired stack height, the number of sheet metal parts in the stacking of the sheet metal parts for the respective lamination stack is reduced by at least one.

12. The method according to claim 1 , wherein in the event that the determined stack height of the lamination stack falls below the desired stack height, the number of sheet metal parts in the stacking of the sheet metal parts for the respective lamination stack is increased by at least one.

13. The method according to claim 1 , wherein the number of sheet metal parts that are stacked to form a lamination stack is always selected in such a way that the determined stack height falls below the desired stack height of the lamination stack by at least a thickness of one sheet metal part of the stacked sheet metal parts.

14. The method according to claim 1 , wherein the placing at least one additional sheet metal part onto the end surface of the relevant lamination stack so as to adjust the stack height occurs by placing one to five sheet metal parts onto the end surface of the lamination stack.

15. The method according to claim 1 , further comprising separating out at least one of the sheet metal parts prior to the stacking and using the at least one of the sheet metal parts for adjusting the stack height before forming the lamination stack.

Assignees

• Voestalpine Stahl Gmbh

Inventors

• Fluch Ronald
• Atzmüller Peter

Classifications

• B21D39/03 Primary

  of sheet metal otherwise than by folding · CPC title

• B21D43/22

  Devices for piling sheets · CPC title

• H01F41/0233

  Manufacturing of magnetic circuits made from sheets (magnetic cores made from sheets H01F27/245; soft magnetic alloys in the form of sheets H01F1/16) · CPC title

• H02K15/12

  Impregnating, moulding insulation, heating or drying of windings, stators, rotors or machines · CPC title

• H02K15/02 Primary

  of stator or rotor bodies · CPC title