METHOD FOR MANUFACTURING AN ELECTRIC MOTOR AND ELECTRIC MOTOR MANUFACTURED ACCORDING TO THE METHOD

Description

[0001] The invention relates to a method for manufacturing an electric motor and an electric motor manufactured according to the method.

[0002] It is generally known that an electric motor has a stator lamination stack housed in a stator casing.

[0003] A synchronous motor is known from US 2017 / 0 085 138 A1.

[0004] A stator for an electric motor is known from WO 2007 / 107 131 A1.

[0005] A stator of a rotating electrical machine is known from DE 10 2014 206 847 A1.

[0006] An engine is known from DE 10 2009 000 621 A1.

[0007] From the US 2020 / 112226 A1 The closest known state of the art is a method for manufacturing an electric motor.

[0008] From the KR 2018 0021468 A is a known stator lamination stack of an electric motor.

[0009] From the US 5 218 252 A A dynamoelectric machine with stator positioning is known.

[0010] From the JP 2005 354870 A is a single lamination of a stator lamination stack.

[0011] From theUS 2008 / 061645 A1 A pump with an electric motor is known.

[0012] The invention is therefore based on the objective of developing a simple method for manufacturing an electric motor.

[0013] According to the invention, the problem is solved in the method according to the features specified in claim 1 and in the electric motor according to the features specified in claim 15.

[0014] Important features of the invention in the method for manufacturing an electric motor are that the electric motor has a stator lamination stack and a stator housing with a receiving bore for receiving the stator lamination stack, wherein the stator lamination stack comprises individual laminations, wherein the stator lamination stack is inserted into the receiving bore by means of a punch part by pressing, in particular during a pressing operation, wherein material areas of at least one of the individual laminations of the stator lamination stack extend radially outwards and create depressions in the wall of the receiving bore, in particular in the bore wall of the receiving bore, during pressing, wherein the stator lamination stack is positively locked in the circumferential direction by means of the depressions, in particular the depressions extending radially outwards.

[0015] An advantage of this method is that the stator lamination stack is pressed in axially using a tool, namely the punch, which has such small contact areas that material sections deflect radially. These deflected sections then scratch the stator housing's receiving bore as the stack is moved axially, creating axially extending depressions. These depressions can be described, for example, as grooves or channels. This results in a positive-locking connection between the stator lamination stack and the stator housing in the circumferential direction.

[0016] Thus, even during the simple axial insertion of the stator lamination stack, deformation of the stack can occur as soon as it is inserted, when the stack only experiences a frictional reaction force against the insertion force. This deformation can cause material from one or more individual laminations of the stack to protrude radially. This protrusion takes effect even before reaching a shoulder in the stator housing that would prevent further insertion of the stack into the receiving bore. Consequently, depressions are cut into the stator housing material starting at the opening, i.e., the end of the receiving bore furthest from the shoulder. In other words, the depressions open into the surrounding material at the end of the receiving bore furthest from the shoulder.In a further development of the invention, after the insertion movement is stopped by the heel, it is possible to increase the pressing force even slightly.

[0017] The mere axial insertion thus causes the positive locking in the circumferential direction by deforming the nearest, i.e., first, individual laminations of the stator lamination stack as seen from the punch part.

[0018] In an advantageous embodiment, the punch section has protruding journals for contact with the stator lamination stack. The advantage here is that a high pressure can be generated due to the small contact area, which enables the desired deformation in the radial direction. However, the material areas projecting radially outwards are arranged circumferentially within a circumferential angle range that encompasses the circumferential angle range covered by the respective journal. Thus, the radial projection is only provided locally in the circumferential direction.

[0019] In an advantageous embodiment, the pressing force is introduced into the stator lamination stack via the journals during the pressing process. The advantage here is that a high pressure can be generated because the journals are the only areas of the punch part that contact the stator lamination stack.

[0020] In an advantageous embodiment, the pins are regularly spaced in the circumferential direction, and in particular regularly spaced from each other. This is advantageous because it allows for a uniform distribution of force.

[0021] In an advantageous embodiment, the stator lamination stack, and in particular the individual laminations of the stator lamination stack, is made of a harder material than the stator housing. An advantage of this is that it allows for easy cutting of the radially protruding material areas into the stator housing.

[0022] In an advantageous embodiment, the stator lamination stack is made of steel, in particular the individual laminations of the stator lamination stack are made of sheet steel, and the stator housing is made of aluminum. An advantage of this is that cutting into the radially protruding material areas in the stator housing is easily possible, especially even with a low pressing force.

[0023] In a preferred design, the individual sheets are manufactured as stamped parts. The advantage here is that simple, cost-effective production is possible.

[0024] In an advantageous embodiment, each pin creates an axially directed recess in the stator lamination stack during pressing. It is advantageous that the recess extends axially.

[0025] In an advantageous embodiment, the stator lamination stack comprises individual laminations welded together and / or individual laminations clamped together and / or individual laminations joined together by stamping. An advantage of this is the ease of manufacturing.

[0026] In an advantageous embodiment, the insertion is terminated by a radially inwardly projecting shoulder of the stator housing after the stator lamination stack has come to rest against the shoulder. The advantage here is that a precisely defined termination of the insertion is provided.

[0027] In an advantageous embodiment, the radially outward projection occurs even before the stator lamination stack contacts the shoulder, meaning that the only reaction force against the pressing force during insertion, and in particular against the pressing of the punch, is the friction between the stator housing and the stator lamination stack. An advantage of this is that even while the first individual lamination is still surrounded by air, the material areas protrude radially, enabling the first lamination to cut into the material of the stator lamination stack as soon as it enters the receiving bore, which is precisely machined to fit the stator lamination stack.

[0028] In an advantageous embodiment, the recesses are formed as grooves and / or furrows. It is advantageous that the recesses extend in the axial direction and are therefore longer in the axial direction than in the circumferential or radial direction.

[0029] In an advantageous embodiment, after the stator lamination stack comes to rest against the shoulder, the punch part is removed. An advantage of this is that axially oriented depressions remain on the first individual lamination, as the pins of the punch part were pressed into these depressions. The punch part itself is made of a hard material, in particular a material harder than that of the individual lamination. A steel harder than that used for the individual lamination can also be used as the material for the punch part.

[0030] Key features of the electric motor manufactured according to the aforementioned method are that the stator lamination stack is positively locked in the stator housing in the circumferential direction, wherein material areas projecting radially outwards on the stator lamination stack extend into radially outwardly directed recesses, in particular grooves and / or slots, in particular wherein the radial spacing area covered by the stator lamination stack overlaps with the radial spacing area covered by the stator housing, in particular wherein the clear radius of the receiving bore is arranged in the radial spacing area of ​​the overlap and / or wherein the radial spacing area covered by the stator lamination stack contains the radius of the receiving bore, and / or wherein the radial spacing area covered by the stator housing adjoins the radius of the receiving bore.

[0031] The advantage here is that a positive fit acting in the circumferential direction can be achieved simply by axial pressing. This makes electric motors easy to manufacture; in particular, a robust connection between the stator housing and the stator lamination stack can be easily created.

[0032] Further advantages arise from the dependent claims. The invention is not limited to the combination of features of the claims. For those skilled in the art, further meaningful combinations of claims and / or individual claim features and / or features of the description and / or the figures will become apparent, in particular from the problem statement and / or the problem arising from a comparison with the prior art.

[0033] The invention will now be explained in more detail with reference to schematic illustrations: In the Figure 1The production of a stator of an electric motor according to the invention is schematically sketched, wherein a stator lamination stack 3 is pressed onto a lamination stack 3 by means of a punch part 1.

[0034] In the Figure 2 An oblique view of stamp part 1 is shown.

[0035] As shown in the figures, the punch part has pins 2 spaced regularly apart from each other in the circumferential direction with respect to the axis of rotation of the rotor of the electric motor. These pins 2 are arranged at the same radial distance, where the radial distance is relative to the axis of rotation of the rotor.

[0036] The stator lamination stack 3 is designed as a stack of individual laminations and is received in a bore of a stator housing 4.

[0037] With one in the Figure 1In the press (not shown), the punch part 1 is pressed in the pressing direction 5, i.e., parallel to the axis of rotation of the rotor, i.e., in the axial direction, onto the lamination stack 3, thus pressing this lamination stack 3 against a shoulder of the stator housing 4. As soon as the lamination stack 3 touches the shoulder, a very high pressing force can be introduced into the lamination stack 3.

[0038] The force introduced into the sheet metal stack 3 even before contacting the shoulder, but rather even more so after contacting the shoulder, is introduced by the press via the punch part 1 and its pins 2 projecting towards the sheet metal stack 3 onto the first individual sheet of the sheet metal stack 3 facing the punch part 1.

[0039] Since the pins 2 have only a very small contact area with the individual sheet, the pressure introduced into the first individual sheet is very high. Therefore, material areas of at least the first individual sheet deflect radially, especially even before the shoulder is contacted by the sheet stack 3.

[0040] Since the stator housing 4 is made of a softer material than the laminated core 3, in particular than the individual lamination of the laminated core 3, and the receiving bore for the laminated core 3 is manufactured to fit precisely, the radially outward-curving material areas of the individual lamination cut a depression, in particular a groove and / or slot, into the stator housing 4, in particular into the inner wall of the stator housing 4.

[0041] The high pressing force introduced into the single sheet via the pins 2 creates axially directed depressions in the single sheet.

[0042] Since the wall thickness of all individual sheets in the sheet stack 3 is very small, the effect described above applies not only to the first individual sheet facing the punch part 1, but also to the individual sheets following the first one in the stack. In particular, with a suitably selected pressing force, the first three or more individual sheets deform.

[0043] The circumferential angle range covered by the radially outward projecting material areas includes the circumferential angle range covered by the pins.

[0044] The material areas created by each pin 2 are spaced apart from each other in the circumferential direction.

[0045] The stacking direction is aligned parallel to the axial direction.

[0046] Preferably, the stator housing 4 is made of aluminum and the lamination stack, especially the individual laminations, is made of steel. Each individual lamination can be manufactured simply and cost-effectively as a stamped part.

[0047] The stator lamination stack 3 is positively secured in the circumferential direction by means of the created recesses.

[0048] The pins 2 are preferably spaced regularly apart from each other in the circumferential direction. Preferably

[0049] In further embodiments according to the invention, the stack is stamped, welded and / or clamped.

[0050] In further embodiments according to the invention, the stack is also bonded by adhesive. Reference symbol list

[0051] 1 Punch part 2 Pin 3 Stator lamination stack 4 Stator housing 5 Pressing direction

Claims

1. Method for producing an electric motor, wherein the electric motor has a laminated stator core and a stator casing that has a receiving hole for receiving the laminated stator core, wherein the laminated stator core has laminations, wherein the laminated stator core is inserted into the receiving hole by press fitting, in particular during a press-fitting operation, by means of a die part, which method thrusts material regions of at least a first of the laminations of the laminated stator core radially outwards and generates recesses in the wall of the receiving hole, in particular in the boring wall of the receiving hole, during the press fitting, wherein the laminated stator core is interlockingly held in the circumferential direction by means of the recesses, in particular the radially outwardly extending recesses, characterised in that the die part has pins which project towards the laminated stator core and which are suitable for displacing material of at least the first of the laminations.

2. Method according to claim 1, characterised in that during the press fitting, the pressing force is introduced into the laminated stator core by means of the pins.

3. Method according to any of the preceding claims, characterised in that during the press fitting, the pressing force is introduced into the laminated stator core by means of the pins.

4. Method according to any of the preceding claims, characterised in that the pins are regularly spaced in the circumferential direction, in particular are regularly spaced apart from one another.

5. Method according to any of the preceding claims, characterised in that the laminated stator core, in particular the laminations of the laminated stator core, is made of a harder material than the stator casing.

6. Method according to any of the preceding claims, characterised in that the laminated stator core is made of steel, in particular the laminations of the laminated stator core are made of sheet steel, and the stator casing is made of aluminium.

7. Method according to any of the preceding claims, characterised in that the laminations are produced as punched parts.

8. Method according to any of the preceding claims, characterised in that during the press fitting, each pin produces one axially oriented recess each in the laminated stator core.

9. Method according to any of the preceding claims, characterised in that the laminated stator core has laminations interconnected by welding and / or laminations interconnected by clamping and / or laminations interconnected by punch-packing.

10. Method according to any of the preceding claims, characterised in that the insertion is terminated by a radially inwardly projecting shoulder of the stator casing once the laminated stator core has abutted or abuts the shoulder.

11. Method according to any of the preceding claims, characterised in that the radially outward thrusting is already brought about before the laminated stator core abuts the shoulder, i.e. while only the friction between the stator casing and the laminated stator core is acting as a reaction force to the press fitting by the die part.

12. Method according to any of the preceding claims, characterised in that the recesses are formed as grooves and / or channels.

13. Method according to any of the preceding claims, characterised in that the die part is removed once the laminated stator core abuts the shoulder.

14. Electric motor produced in accordance with a method according to any of the preceding claims, characterised in that the laminated stator core is interlockingly held in the stator casing in the circumferential direction, wherein material regions projecting radially outwards on the laminated stator core project into radially outwardly oriented recesses, in particular channels and / or grooves, in particular wherein the radial clearance region covered by the laminated stator core overlaps with the radial clearance region covered by the stator casing, in particular - wherein the clear radius of the receiving hole is arranged in the radial clearance region of the overlap, - and / or wherein the radial clearance region covered by the laminated stator core includes the radius of the receiving hole, - and / or wherein the radial clearance region covered by the stator casing adjoins the radius of the receiving hole.