Brake device for realizing stacked packages for electrical applications

Abstract

A brake device (10, 10') for realizing a laminated package for electrical applications, defined by a stack of magnetic laminations formed by shearing, comprising: The brake device is connected to the shear device (13) below the shear mold (14), The braking device comprises a brake block (15, 15') having an opening (16, 16'), the openings (16, 16') have a shape corresponding to the shape of the stack (12') and a size smaller than the size of the stack, defining an interference (Δ) with the stack that acts on the packing of the stack; The braking device (10, 10') comprises mechanical stress compensation means adapted to keep the interference (Δ) constant.

Description

Technical Field

[0001] The present invention relates to a braking device for realizing a laminated package for electrical applications.

[0002] More specifically, the present invention relates to a braking device used in a shear mold adapted to obtain a magnetic laminate starting from a metal sheet. Here, the magnetic laminate is packed or stacked on top of each other to define a laminated package for use in electromechanical devices such as motors, generators, transformers, meters, ignition coils, and similar electrical equipment.

Background Art

[0003] As is known, the aforementioned laminated package is made by stacking individual laminates (which are defined by a single body or consist of laminate parts assembled together to define a laminate) in direct contact with each other.

[0004] The realization of the laminated package is traditionally done by overlapping and connecting individual laminates obtained from a shear mold forming the laminate, for example, by punching. Also, the realization of the laminated package is done by overlapping and connecting individual laminates obtained from a strip laminate, as in the case of conventional shear methods mentioned in, for example, US2017 / 0106427 and JP6676815. And the laminates can be overlapped and connected to each other on the same machine forming a single laminate, as described in, for example, JP2008078345, after being formed.

[0005] The laminates can be connected to each other using coupling or hook parts called "staples" or "embossments" obtained by deforming the laminate itself at specifically selected positions. The laminate parts are introduced into corresponding recesses of the lower laminate during the coupling step, pushed in, and continuously overlapped to form a laminated package.

[0006] For this purpose, a rigid element is typically placed inside the laminate shear mold, beneath the shear element. This is called a brake and is characterized by a size reduced relative to the size of the shear element and interference (related to the aforementioned size difference with the shear element) that can break the shear element. As an example, when shearing a circular laminate and considering a shear element with a diameter of 10 mm, the brake element must have a radius approximately equal to, for example, 9.99 mm, so as to define an interference Δ of 0.01 mm between the diameter of the laminate (having a diameter equal to the diameter of the shear element) and the diameter of the brake element. Such 0.01 mm interference along the entire circumference of the circle (considering the example of a circular laminate) generates a force in the opposite direction to the shear load, thereby causing the laminate to remain "stuck" within the brake that forms the laminate package. Conventional brake devices (or counterpunches) with the above-described features are described, for example, in EP3235577 or EP2902129 or US2012 / 0241095.

[0007] For the reasons stated above, it is clear that brake elements define the fundamental mechanism in the realization and packing process of individual laminates that define a laminated package. This is because only in the presence of brake elements can the necessary reaction force be generated to allow the packing embossing of the laminate to interfere during the shearing process.

[0008] Therefore, such a rigid braking element is subjected to mechanical stress generated by interference between the braking element and the sheared laminate. If this stress is too high, it can lead to the formation of pickups on the shear profile (and thus the laminated package) and failure of the shear element itself.

[0009] Furthermore, it is known that the stress within the brake element is not constant throughout the lifespan of the mold. In fact, wear of the shear profile and the resulting increase in shear clearance lead to an increase in the size of the shear profile, and consequently, an increase in the interference with the brake element.

[0010] Increased interference between the laminate and the braking element represents a substantial and significant drawback. This is due to the fact that such interference is caused, firstly, by the formation of pick-ups on the tracked element, and secondly by the failure of the shear element, as described above.

[0011] In fact, taking the above example related to a laminate obtained using a shear element with a diameter of 10 mm, at the beginning of the lifespan of the shear mold, the diameter portion of the resulting laminate is equal to 10 mm (i.e., equal to the diameter of the shear element). Then, after "n" strokes of the shear element (typically n million strokes) (the value of "n" depends on the wear of the mold), the diameter of the laminate may grow to a value equal to, for example, 10.01 mm. Considering that the brake element has a fixed size equal to 9.99 mm, at the beginning of the lifespan of the mold, the size difference between the brake element and the shear mold is equal to 0.01 mm, and after "n" work cycles, the same difference will be equal to 0.02 mm.

[0012] The aforementioned increase in interference is undesirable, given that it causes an increase in the stress values ​​of the braking elements, resulting in undesirable failure of both the braking and shear elements.

[0013] This problem is particularly noticeable in the case of "T" profile lamination. The presence of angles within the profile defines the presence of "problematic" regions, because, as is known, angles define stress-intensifying zones, which in turn represent weakening points of shear elements, potentially leading to deformations and stresses that can result in crack formation.

[0014] As a consequence, the above drawbacks are accompanied by the fact that the lifespan of the shear mold is shortened, which, as a further negative consequence, leads to an increase in the costs associated with the shear mold.

[0015] To mitigate the aforementioned drawbacks, shear molds undergo regular maintenance, which includes "grinding" the mold, i.e., "restoring" the shear profile to restore the aforementioned clearance. This operation requires grinding the shear elements of the mold, resulting in a reduction in the mold's height and consequently a shorter mold lifespan.

[0016] The aforementioned drawbacks lead to further disadvantages, manifested by the fact that the grinding operation requires the shearing equipment to be stopped, which results in increased production time and, consequently, increased costs for all associated activities.

[0017] Further drawbacks associated with increased interference values ​​manifest as a decrease in the quality of individual laminates, and therefore, a loss of quality in the laminated package resulting from the overlapping of the laminates. These lead to related problems in electrical equipment incorporating the package, in terms of performance, efficiency, and the generation of undesirable vibrations and noise. [Overview of the project] [Problems that the invention aims to solve]

[0018] The objective of this invention is to overcome the above-mentioned drawbacks.

[0019] More specifically, an object of the present invention is to provide a braking device for realizing a laminated package for electrical applications that is adapted to avoid increased interference between the braking element and the shear mold during the laminated shear step.

[0020] Another object of the present invention is to provide a braking device that can absorb deformation of a sheared laminate during the shearing process while avoiding the formation of pickups on the shear profile.

[0021] A further object of the present invention is to provide a braking device adapted to prevent premature wear and / or breakage of a shear mold.

[0022] Another object of the present invention is to provide a braking device for a shearing device that enables ensuring the quality of a sheared laminate. Thus, another object of the present invention is to provide a braking device for a shearing device that enables the realization of a laminated package characterized by optimal efficiency and the absence of vibration and / or noise in an electromachinery that mounts the laminated package.

[0023] Another objective of the present invention is to provide users with a braking device for electrical applications that is adapted to ensure high resistance and durability over long periods and to be easily and economically manufactured in a laminated package. [Means for solving the problem]

[0024] These and other objectives are achieved by the present invention having the features of claim 1.

[0025] According to the present invention, the following is provided. A braking device for realizing a laminated package for electrical applications, defined by the overlapping of magnetic laminates formed by shearing, The brake device is connected to the shearing device below the shearing mold. The brake device comprises a brake block having an opening, The aforementioned opening has a shape corresponding to the shape of the laminate and a size smaller than the size of the laminate, and defines the interference (Δ) with the laminate that acts on the packing of the laminate. The brake device includes mechanical stress compensation means adapted to keep the interference (Δ) constant, the brake device.

[0026] Advantageous embodiments of the invention are apparent from the dependent claims.

[0027] The structural and functional features of the brake device for realizing a stacked package for electrical applications of the present invention can be better understood from the following detailed description with reference to the accompanying drawings, which represent preferred non-limiting embodiments.

Brief Description of the Drawings

[0028] [Figure 1] FIG. 1 schematically shows an axonometric view of a stacked package having a "T" profile. [Figure 2] FIG. 2 schematically shows a cross-sectional view of a stacked shear and package device provided with the brake device of the present invention. [Figure 3] FIG. 3 schematically shows a plan view of the brake device for realizing the stacked package of the present invention. [Figure 4] FIG. 4 schematically shows an axonometric view of the brake device of the present invention according to the configuration of an alternative embodiment.

Modes for Carrying Out the Invention

[0029] Referring to FIGS. 1 to 3, a brake device for realizing a stacked package for electrical applications of the present invention will be described. FIGS. 1 to 3 describe the realization of a stacked package having a "T" profile, that is, a stacked package composed of a plurality of "T" - shaped laminates 12'. Here, in the stacked package composed of a plurality of "T" - shaped laminates 12', the "T" - shaped laminates 12' overlap each other to form the package 12, and this package 12 forms a part or module of a stacked package of a rotor or a stator core (for example, a disc - shaped). (The features of such a stacked package are known and are not described in detail herein.)

[0030] Figure 2 schematically shows a shearing device 13 comprising a shearing mold 14 and a braking device 10. As is well known, the braking device 10 is positioned below the shearing mold 14. The braking device 10 has a size A1 that is slightly smaller than the size A of the shearing mold in order to generate the interference "Δ" required for packing the laminate 12', as described above. (For a disc-shaped laminate, sizes A and A1 represent the diameters of the shearing mold and the braking device.)

[0031] Figure 3 shows a cross-sectional plan view of the brake device 10 of Figure 2, which includes a brake block 15 (made of steel or sintered material, composite material, or other material suitable for the purpose). The brake block 15 has an opening 16 formed along the axis of movement of the shear element (not shown) of the shear device 13. The shape of the opening 16 is realized according to the shape of the profile of the laminate 12' that has been sheared to form the laminate package 12, and in the particular case of Figure 3, the shape of the opening 16 of the block 15 is "T" shaped, i.e., similar to the shape of the laminate package 12 in Figure 1.

[0032] Outside the opening 16, a through-hole or non-through-type pocket 18 is formed along the periphery of the opening, extending for the thickness of the block 15 of the brake device 10.

[0033] Preferably, the pocket 18 has the shape of an elongated hole in cross-section (by a plane perpendicular to its extension direction in the thickness of the block 15). It should be understood that the shape of the pocket may also be different.

[0034] The pocket 18 is realized in the stress-reinforced zone of the laminate 12', i.e., in areas where stress is more concentrated (for example, at the edges or in zones with cross-sectional changes). The stress-reinforced zone of the laminate 12' corresponds to the weakened area of ​​the shear element.

[0035] A single pocket 18 is positioned in each of the specific predetermined yield zones of the brake block 15 that correspond to the yield zones of the laminate. It has a length extension along a plane perpendicular to the extension direction of the same pocket in the thickness of the block 15, which substantially corresponds to the extension of the yield zone of the laminate 12'. In particular, the length and width size of the single pocket 18 is due to the deformation of the single laminate 12' sheared by the shear element.

[0036] Each single yield zone of block 15 contains at least one pocket 18, the number of which depends on the extension of the yield zone of block 15 and therefore on the magnitude of a given stress (because this is calculated in advance during the design phase of the type of laminated package to be created).

[0037] Therefore, between the single pocket 18 of the block 15 and the opening 16, there is a block portion 15 that defines a thin wall or membrane 19 separating the pocket from the opening 16, and its function will become clearer below.

[0038] The pockets 18, due to their location and the presence of thin walls or membranes 19, form an "impact absorber" during the shearing and packing process of the laminate. More specifically, the pockets 18 expand during shearing of the laminate, which allows them to absorb the deformation of the thin walls or membranes 19 caused by interference between the laminate and the brake device, as described above.

[0039] The position of the pockets 18 is due to the deformation of the yield zone or region of the block 15 of the braking device 14. More specifically, the pockets 18 are positioned and realized so that they all expand by the same amount when subjected to the same force. (Consider a thin wall or membrane 19 defining an elastic wall or membrane.) In practice, the increase in the size of the laminate is assumed to be the same around the entire perimeter of the lamination for the lifespan of the shear mold. (Considering the above description, in practice, the size of the laminate is due to the shear clearance of the shear elements, which is the same throughout the entire shear profile.)

[0040] Referring to Figure 4, an alternative embodiment of the brake device of the present invention is shown, the whole being shown as 10'. This brake device comprises a brake block 15' (similarly made of steel or sintered material, composite material or other material suitable for the purpose) having an opening 16' formed according to the direction of axial movement of the shear elements (not shown) of the shear device 13. The shape of the opening 16' is realized depending on the type of laminated profile (e.g., circular laminate) that has been sheared to form a laminated package.

[0041] Outside the opening 16', a pocket 18' is formed along the periphery of the opening. In this embodiment, the pocket 18' extends axially over a finite length within the thickness of the brake body 15', defining a non-penetrating pocket, which is then distributed radially.

[0042] In the embodiment shown in Figure 4, the pocket 18' is formed transversely to the longitudinal / axial extension direction of the brake body, starting from the outer surface 15B of the brake body and toward the inner surface 15C of the brake body 15. This defines a pocket that is either open transversely or penetrates along the aforementioned transverse direction. However, the pocket may not penetrate along the aforementioned transverse direction in order to define a membrane or thin wall between the single pocket and the opening 16' as described above.

[0043] The presence of pocket 18(18') allows the brake device 10(10') to self-adapt to the shape of the laminate during the shearing process of the laminate itself.

[0044] Mechanical tests were performed on the device under different force conditions applied to the opening 16(16') of the brake block 15(15') of the brake device 10(10'). These mechanical tests revealed that the displacement trend (measured in millimeters) (Graph 1) and stress trend (measured in megapascals [MPa]) (Graph 2) of the yield element (defined by pocket 18(18')) were linear as a function of the applied force. [Table 1] [Table 2]

[0045] Figures 1 to 3 show a braking device for realizing a laminated package having a "T" profile. However, it should be understood that the stress compensation or "shock absorption" means described above can also be applied to laminates having different profiles, such as disc-shaped profile laminates.

[0046] As can be seen from the above, the advantages achieved by the braking device for realizing the stacked package of the present invention are clear.

[0047] The braking device for realizing the laminated package of the present invention advantageously enables the prevention of damage to shear elements during the laminated shearing process.

[0048] A further advantage of the braking device of the present invention is represented by the fact that it makes it possible to eliminate the pickup of sheared profiles.

[0049] A further advantage is that the "shock absorption" behavior of the brake device of the present invention makes it possible to keep the "Δ" between the brake and the sheared laminate constant, thereby avoiding the generation of interference forces that tend to damage the shear elements.

[0050] Furthermore, the fact that the elastic behavior of the braking system allows for a reduction in the number of times the mold needs to be ground, and consequently reduces machine downtime and associated costs, is advantageous.

[0051] A further advantage is that the pockets in the brake device define the yield elements of the same brake. If the sheared laminate expands excessively, failure of such yield elements occurs rather than failure of the shear elements, resulting in cost savings, considering that the cost of the shear elements and molds is far higher than the cost of the brake device itself.

[0052] A further advantage is that the braking device of the present invention enables the assurance of optimal quality of the sheared laminate, and therefore enables the realization of a laminate package characterized by optimal efficiency and the absence of vibration and / or noise in an electromachine incorporating the laminate package.

[0053] Although the present invention has been described above with particular reference to embodiments given merely as non-limiting examples, numerous modifications and variations will be apparent to those skilled in the art in light of the above description. Accordingly, the present invention is intended to encompass all modifications and changes included in the claims.

Claims

1. A braking device (10, 10') for realizing a laminated package for electrical applications, defined by the overlapping of magnetic laminates formed by shearing, The brake device is connected to the shearing device (13) below the shearing mold (14). The brake device comprises brake blocks (15, 15'), The brake blocks (15, 15') have openings (16, 16') formed in the direction of the movement axis of the shear element of the shearing device (14), The openings (16, 16') have a shape corresponding to the shape of the laminate (12') sheared by the shear element, and have a size (A1) smaller than the size (A) of the shear mold (14) forming the laminate, defining the interference (Δ) acting on the packing of the laminate (12'). The braking device comprises mechanical stress compensation means adapted to keep the interference (Δ) constant, The mechanical stress compensation means comprises pockets (18, 18'), The brake device (10, 10') is characterized in that the pockets (18, 18') are formed outside the openings (16, 16') of the brake blocks (15, 15'), extend along the thickness direction of the brake blocks, and are distributed along the periphery of the openings (16, 16').

2. The brake device according to claim 1, characterized in that the pockets (18, 18') are formed in the zone of the brake blocks (15, 15') in the stress-reinforcement zone of the laminate (12'), and the stress-reinforcement zone corresponds to a weakened region of the shear element where stress is more concentrated.

3. The brake device according to claim 1 or 2, characterized in that the aforementioned pockets (18, 18') are of the through type.

4. The brake device according to claim 1 or 2, characterized in that the aforementioned pockets (18, 18') are of the non-through type.

5. The brake device according to any one of claims 1 to 4, characterized in that the pockets (18, 18') have an extension of a length corresponding to the extension of the stress-reinforcement zone of the laminate (12').

6. The brake device according to any one of claims 1 to 5, characterized in that each stress-reinforcement zone of the laminate (12') is provided with at least one pocket (18, 18').

7. The brake device according to any one of claims 1 to 6, wherein the mechanical stress compensation means comprises a thin wall or membrane (19) on the brake block (15, 15') separating the pockets (18, 18') and the openings (16, 16'), and the thin wall or membrane (19) defines an elastic wall or membrane that acts against the expansion of the pockets (18, 18') in response to the deformation of the laminate (12').

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