Method for manufacturing a rotor and rotor

Abstract

The invention relates to a method for producing a rotor, in particular for a current-excited electric machine, comprising the following steps: - providing a plurality of sheet elements and arranging these sheet elements into a lamination stack, the lamination stack having a plurality of laminations; - arranging an end plate on the lamination stack on the end side, the end plate being designed to axially support the lamination stack; - axially fixing or pre-tensioning the lamination stack by winding the laminations with a conductor material; - arranging a rotor shaft, in particular by means of a press joint or a transverse joint, in the fixed or pre-fixed lamination stack.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a rotor (especially a rotor for a current-excited motor) and a rotor for a current-excited motor. Background Technology

[0002] To avoid eddy current losses, the sheet metal laminations of the illustrated type are constructed from thin, stamped sheet metal. The rotor shaft arrangement within these laminations is typically achieved through a press-fit joint, in which the sheet metal laminations are heated and the rotor shaft is cooled. This is not without its problems, as the sheet metal sheets deform upon cooling due to stress induced during stamping. Without support or axial clamping, the sheet metal laminations may laterally tilt or bulge. To compensate for this undesirable effect, these sheet metal laminations are typically connected by threads or axially clamped using additional components. However, this is technically costly in manufacturing, increases costs, and further requires additional structural space. Summary of the Invention

[0003] Therefore, the object of the present invention is to provide a method for manufacturing a rotor and a rotor that eliminates the disadvantages mentioned above and is simply constructed and can be cost-effectively implemented.

[0004] Therefore, the present invention proposes a method for manufacturing a rotor, the method comprising the following steps: - providing a plurality of lamellar elements and arranging these lamellar elements into a lamellar assembly having a plurality of slats; - placing an end disc on the end side of the lamellar assembly, the end disc being designed to axially support the lamellar assembly; - axially pre-tightening the lamellar assembly by winding the slats with a conductive material with sufficient pre-tension, such that deformation of the slats is avoided during cooling of the lamellar assembly after engagement of the rotor shaft; - arranging the rotor shaft in a fixed or pre-fixed lamellar assembly.

[0005] The present invention also proposes a rotor comprising a lamination assembly consisting of a plurality of lamination elements and a plurality of slats, wherein an end disk is arranged on the end side of the lamination assembly, the end disk being designed to axially support the lamination assembly, a conductor material being wound around the slats with sufficient preload to prevent deformation of the slats during cooling of the lamination assembly after engagement of the rotor shaft, the rotor shaft being arranged in the lamination assembly, and at least one end disk having a recess designed to absorb axial deformation of the lamination assembly.

[0006] The present invention also proposes an electric motor comprising a rotor manufactured by means of the method according to the present invention.

[0007] According to the present invention, a method for manufacturing a rotor (especially a rotor for a current-excited motor) includes the following steps:

[0008] - Provide multiple sheet elements and arrange these sheet elements into a stack, the stack having or being shaped into multiple strips;

[0009] - The end plate is arranged on the end side of the lamination assembly, and the end plate is designed to support the lamination assembly axially;

[0010] -Axially fix or pre-tighten the lamination assembly by wrapping the strips or end discs with conductive material;

[0011] - The rotor shaft is arranged, especially by extrusion or transverse joining, in a fixed or pre-fixed or pre-tightened lamination assembly.

[0012] Advantageously, the winding on the rotor side is fully or at least partially arranged before the rotor shaft is arranged on the lamination assembly in order to achieve preload on the rotor shaft, especially in the axial direction. In other words, the structure including the lamination assembly and the end discs arranged on the end side is preloaded or fixed, especially in the axial direction, by the fully or at least partially arranged winding, so that no deformation occurs when the lamination assembly is cooled after the rotor shaft is engaged.

[0013] Suitablely, the rotor shaft is arranged or joined in the lamination assembly by means of a press fit. Accordingly, a press fit is applied between the corresponding opening of the lamination assembly and the rotor shaft. Preferably, a transverse press fit structure is implemented. Before assembly, the rotor shaft is cooled and the lamination assembly is heated accordingly. Any deformation that may occur, especially in the slat areas of the lamination assembly, is effectively avoided or compensated for by pre-tightening applied by means of the winding material.

[0014] According to a preferred embodiment, a wire-shaped conductor material, such as copper wire with a round, especially kreis-round, cross-section, is used as the conductor material. To achieve good preload, the end disc is suitably constructed with corresponding bending rigidity. Preferred materials are metallic materials, such as aluminum or its alloys. Depending on cost objectives, the end disc can be a machined (metal) casting or a milled part. Non-metallic materials, especially composite materials, such as carbon fiber reinforced plastics, are also well-suited due to the high stiffness achievable. Importantly, by selecting materials and designing the structure in this way, the (bending) stiffness is designed so that sufficient preload can be built into the stack of sheets through the winding.

[0015] Suitablely, the end discs continue the shape of the laminated assembly, i.e., they also have slats. Suitablely, the end discs support the laminated assembly on their respective end sides across the entire surface.

[0016] Preferably, the end disc has a turning region designed to deflect the conductor material. The turning region is preferably designed to be rounded or chamfered to allow for gentle winding. This also enables winding under high preload without damaging the conductor material at the edges, etc.

[0017] According to a preferred embodiment, the sheet element is formed from an electrical sheet (Elektroblech). This forming is preferably cost-effective and the process is reliably carried out using a separation method, particularly stamping. Alternative separation methods, especially those for slitting (e.g., shearing), are also feasible. A common feature of these methods is that stress is introduced into the sheet element, which can subsequently lead to undesirable deformation characteristics. Along the separation edge, cutting edge, or stamping edge, the sheet element has stamping burrs, which are oriented in a specific direction according to the cutting or stamping direction. The sheet element deforms along this direction upon cooling. Here, the burrs are, in principle, substantially perpendicular to the plane of the sheet element.

[0018] A chip element can also be called a sheet metal chip. Correspondingly, a stacked assembly is a stack of sheet metal chips.

[0019] Suitablely, the method includes the following steps:

[0020] - Orient the sheet elements in the stack such that one or more stamping burrs are oriented in a preferred direction;

[0021] - A gap is provided in the end plate, which is oriented toward the preferred direction in order to absorb the deformation of the laminations in the region of the rotor shaft.

[0022] Advantageously, the deformation of the lamination assembly in the slat region can be effectively compensated by the preload applied by the winding material. Since the end disc is not infinitely rigid, it is also impossible to sufficiently preload the lamination assembly close to the axis via the end disc. Therefore, allowing small deformations of the lamination assembly in this region has proven extremely effective. This is suitably achieved by the end disc, oriented towards the deformation direction of the lamination assembly, having corresponding recesses or gaps to absorb the deformation. The preferred direction mentioned above is particularly along which deformation occurs when the lamination assembly cools. As shown, this is caused by the direction of one or more stamping burrs.

[0023] According to one implementation, the method includes the following steps:

[0024] - Orient the sheet elements in the stack in such a way that the stamping burrs are alternately oriented.

[0025] This allows for the advantageous realization that at least some degree of deformation can be compensated within the laminated assembly.

[0026] According to one embodiment, the stacked assembly includes multiple segments, wherein each segment includes multiple chip elements. According to one embodiment, the method includes the following steps:

[0027] - This arrangement of the sheet elements ensures that the stamping burrs are oriented in the same way in these sections;

[0028] - Orient these sections in such a way that the stamping burrs are alternately oriented within these sections.

[0029] Therefore, it can also advantageously compensate for deformation characteristics.

[0030] According to one implementation, the method includes the following steps:

[0031] - The rotor shaft is arranged along the preferred direction.

[0032] This allows for the advantageous realization that any frictional forces that may exist between the rotor shaft and the lamination assembly are manifested in the desired direction during thermal bonding.

[0033] According to one implementation, the method includes the following steps:

[0034] - The rotor shaft is arranged along the engagement direction until a target position is reached, wherein the target position is prior to the final position relative to the engagement direction.

[0035] Advantageously, deformation is taken into account when arranging the rotor shaft, thereby achieving a precise final position after cooling. The axial movement of the rotor shaft caused by the deformation of the lamination assembly is suitably compensated for by providing a compensation value in the joining tool when engaging the rotor shaft.

[0036] According to one implementation, the method includes the following steps:

[0037] -Pre-fix the stacked pieces radially during winding.

[0038] For this purpose, a shaft can be advantageously arranged in the rotor opening, which is used at least temporarily for locating the radially positioned elements.

[0039] According to one embodiment, the stacked pieces (together with the end discs) are pre-fixed axially to facilitate the arrangement of the winding.

[0040] The present invention also relates to a rotor comprising a lamination group consisting of a plurality of lamination elements, wherein end disks are arranged on the end sides of the lamination group, and at least one end disk has a recess or gap designed to absorb axial deformation of the lamination group.

[0041] Each end disc has a support surface designed to rest against the laminations at its end. In the installed state, the support surface is oriented perpendicular to or substantially perpendicular to the rotor axis. Suitably, the support surface is constructed flat, flat, or planar. The aforementioned recesses or gaps are preferably constructed as annular, especially circular, recesses near the axis on the support surface.

[0042] Suitablely, the laminations are axially pre-tensioned in the region of their slats by a winding applied before the rotor shaft is arranged. Suitablely, additional components, such as retainers, tensioning elements, threaded connections, etc., can be omitted. This rotor is optimized in terms of its structural space requirements. Furthermore, cost and weight can be saved by eliminating additional components.

[0043] According to one embodiment, the lamination element has stamped burrs, wherein the stamped burrs are oriented toward the recess. Therefore, the aforementioned recess can advantageously and effectively absorb deformation of the lamination assembly in the region of the rotor opening.

[0044] The present invention also relates to an electric motor comprising a rotor manufactured according to the method of the present invention. Preferably, it relates to a current-excited synchronous motor. Attached Figure Description

[0045] Other advantages and features are described below with reference to the accompanying drawings.

[0046] In the attached diagram:

[0047] Figure 1 One embodiment of the rotor is shown in perspective view;

[0048] Figure 2 Shown in Figure 1 The cross-sectional view of the rotor shown. Detailed Implementation

[0049] Figure 1 A rotor having laminations 10 is shown in perspective, wherein the laminations constitute a plurality of slats 14. End discs 20 are respectively constructed on the end sides of the laminations 10. A rotor shaft 60 is disposed in the laminations 10. This arrangement is such that the rotor shaft 60 is cooled when the laminations 10 is heated. Especially when the laminations are stamped, deformation occurs during cooling. To compensate for this deformation, the laminations 10 are wound with a conductive material before the rotor shaft 60 is arranged, see winding 40. It has been shown that this allows for axial preload, which resists deformation of the laminations, especially in the areas of the slats 14. This, in particular, enables engagement with the end discs 14, which are suitably constructed to bend rigidly accordingly.

[0050] Figure 2 The cross-sectional view shows the result of Figure 1A known rotor. The lamination assembly 10 is particularly visible. This is constructed of multiple individual, thin lamination elements, though these elements are not visible in this diagram. The lamination assembly 10 has an opening 12 in which a rotor shaft 60 is arranged. This rotor shaft is specifically constructed as a hollow shaft, which includes an arrangement region 62. This arrangement region 62 is suitably designed to introduce torque into or out of the rotor. In the embodiment shown here, the arrangement region is constructed as a spline. The rotor shaft 60 extends along the rotor axis R. End discs 20 are arranged on the end sides of the lamination assembly 10, each end disc 20 also having an opening 64 through which the rotor shaft 60 passes. Each end disc 20 has a support surface 24 configured to abut against the lamination assembly 10 at its end side. Reference numeral 26 indicates a turning region of the end disc 20, on which the winding abuts and turns. In the embodiment shown here, the left end disc 20 has a recess 22 in the region of the support surface 24, which is designed to absorb deformation of the lamination assembly 10 in that region. The lamination elements, which are not visible in the embodiment shown here, are arranged such that their stamping burrs are oriented toward the aforementioned recess 22. During cooling, the lamination assembly 10 is constructed toward the recess 22 in the region of the opening 12. By providing the compensation space, no additional tension occurs within the entire arrangement including the end disc 20 and the lamination assembly 10. The geometry of the final state advantageously remains orthogonal to the rotor axis R. The rotor shaft 60 is suitably arranged along the engagement direction F. It has been shown that the frictional forces that may therefore exist between the rotor shaft 60 and the lamination assembly 10 manifest in the desired direction during thermal joining. Due to the deformation characteristics of the lamination assembly 10, there is axial movement of the rotor shaft 60 within the lamination assembly 10 during cooling. This axial movement is suitably compensated by providing a compensation value in the engagement tool when engaging the rotor shaft 60.

[0051] List of reference numerals

[0052] 10-piece stack

[0053] 12 Openings

[0054] 14 slats

[0055] 20 End plate

[0056] 22 recess

[0057] 24 Support surface

[0058] 26 Turning Area

[0059] 40. Entanglement

[0060] 60 Rotor Shaft

[0061] 62. Arrangement Area

[0062] 64 Opening

[0063] R rotor axis

[0064] F Joint direction

Claims

1. A method for manufacturing a rotor, the method comprising the following steps: - Provide multiple sheet elements and arrange these sheet elements into a stack (10), the stack (10) having multiple strips (14); - An end plate (20) is arranged on the end side of the lamination group (10), the end plate (20) being designed to axially support the lamination group (10). - By axially pre-tightening the lamination assembly (10) with sufficient pre-tightening force by wrapping the slats (14) with conductive material, deformation of the slats is avoided when cooling the lamination assembly after engaging the rotor shaft; - Arrange the rotor shaft (60) in a fixed or pre-fixed lamination group (10).

2. The method according to claim 1, wherein, The sheet element is stamped and has stamping burrs, the method includes the following steps: - Orient the sheet elements in the stack (10) such that the stamping burrs are oriented in a preferred direction; - A gap is provided in the end plate (20) and the gap is oriented toward the preferred direction in order to absorb the deformation of the lamination group (10) in the region of the rotor shaft (60).

3. The method according to claim 2, wherein, The method includes the following steps: - Orient the sheet elements in the stack (10) such that the stamping burrs are oriented alternately.

4. The method according to any one of claims 2 to 3, wherein, The method includes the following steps: - The rotor shaft (60) is arranged along the preferred direction.

5. The method according to any one of claims 1 to 3, wherein, The method includes the following steps: - Arrange the rotor shaft (60) along the engagement direction (F) until a target position is reached, which is prior to the final position relative to the engagement direction (F).

6. The method according to any one of claims 1 to 3, wherein, The method includes the following steps: - The stack of sheets (10) is pre-fixed radially during winding.

7. The method according to claim 1, wherein, The rotor is a rotor used in a current-driven motor.

8. The method according to claim 1, wherein, The rotor shaft (60) is arranged in a fixed or pre-fixed lamination group (10) by extrusion or transverse joining.

9. A rotor comprising a lamination group (10) consisting of multiple lamination elements and multiple slats (14), wherein, An end plate (20) is arranged on the end side of the lamination assembly (10), the end plate (20) being designed to axially support the lamination assembly (10), the conductor material being wound around the strip (14) with sufficient preload to prevent deformation of the strip during cooling of the lamination assembly after engagement of the rotor shaft, the rotor shaft (60) being arranged in the lamination assembly (10), and at least one end plate (20) having a recess (22) designed to absorb axial deformation of the lamination assembly (10).

10. The rotor according to claim 9, wherein, The stacked slabs (10) are axially pre-tightened in the region of their slats (14) by the winding (40).

11. The rotor according to claim 9 or 10, wherein, The sheet element has stamped burrs oriented toward the recess (22).

12. An electric motor comprising a rotor manufactured by any one of claims 1 to 8.

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