阅读说明：本技术 制造用于电动机的铁磁芯的方法及其制造的铁磁芯 (Method of manufacturing a ferromagnetic core for an electric motor and ferromagnetic core manufactured thereby ) 是由 L·韦尔蒂诺 A·马尔维斯蒂蒂 于 2019-07-23 设计创作，主要内容包括：本发明涉及一种制造用于电动机的铁磁芯的方法,所述铁磁芯由布置成闭合的圆形配置的多个层叠节段(S-1-S-N)形成。所述铁磁芯包括层叠片的第一辅助层(L-1；L-M；L-j’)和层叠片的第二辅助层(L-2；L-(M-1)；L-j"),第一辅助层具有突起的销部(23,43)和凹部(22,32,42),突起的销部(23,43)位于形成每个层叠节段的层叠片的轭座(12)的一端的凸部(21,41)附近,凹部(22,32,42)位于在层叠片的第一辅助层(L-1；L-M；L-j’)中形成每个层叠节段的轭座(12)的相对端,第二辅助层(L-2；L-(M-1)；L-j")具有开口(33),开口(33)位于形成每个层叠节段的层叠片的轭座(12)的一端的凸部(31)附近。层叠片的第一辅助层(L-1；L-M；L-j’)的销部与层叠片的第二辅助层(L-2；L-(M-1)；L-j")的开口(33)接合。(The invention relates to a method for manufacturing a ferromagnetic core for an electric motor, said ferromagnetic core being formed from a plurality of stacked segments (S) arranged in a closed circular configuration 1 ‑S N ) And (4) forming. The ferromagnetic core comprises a first auxiliary layer (L) of laminated sheets 1 ；L M ；L j ') and a second auxiliary layer (L) of the laminate 2 ；L M‑1 ；L j "), the first auxiliary layer having raised pin portions (23, 43) and recessed portions (22, 32, 42), the raised pin portions (23, 43) being located adjacent to the raised portions (21, 41) at one end of the yoke seat (12) of the laminated sheet forming each laminated segment, the recessed portions (22, 32, 42) being located on the first auxiliary layer (L) of the laminated sheet 1 ；L M ；L j ') opposite ends of a yoke seat (12) forming each laminated segment, a second auxiliary layer(L 2 ；L M‑1 ；L j ") has an opening (33), the opening (33) being located in the vicinity of a projection (31) forming one end of a yoke seat (12) of the lamination sheet of each lamination segment. A first auxiliary layer (L) of the laminate 1 ；L M ；L j ') pin portion and a second auxiliary layer (L) of the laminate sheet 2 ；L M‑1 ；L j ") are engaged.)

1. A method of manufacturing a ferromagnetic core (10, 110) for an electric motor, the ferromagnetic core being formed of a plurality of stacked segments (S)₁-S_N) Forming, said laminated segments consisting of bundles of laminated sheets, each layer (L) being punched out₁-L_M) During lamination of the sheets, the segments (S) are laminated₁-S_N) Connected together to form a closed circular configuration in which each of the stacked segments (S)₁-S_N) Substantially in the shape of a circular arc with an inwardly protruding polar expansion (11) and a yoke seat (12) arranged on the outside with respect to the central axis of the ferromagnetic core (10, 110), wherein the laminations of each lamination segment are connected together by crimping sections (13), and wherein the lamination segments (S)₁-S_N) Is connected to adjacent segments along the yoke seat (12) and is capable of reciprocating rotation, the method comprising the steps of:

a) feeding a foil (100) of ferromagnetic material along a blanking station and a pressing station of a blanking/pressing device;

b) forming one or more crimps (13) and corresponding cavities (13', 14) by stamping on the lamination sheet of each segment;

c) blanking an initial layer (L) of laminations in a closed circular configuration of a ferromagnetic core (10, 110)₁) And pushing it into an accumulation chamber of a cutting die of said blanking/compression die apparatus;

d) punching a plurality of intermediate layers (L) of laminations in a closed circular configuration of a ferromagnetic core (10, 110)_j) And by laminating each intermediate layer (L) of the laminate_j) Is coupled with a corresponding cavity (13', 14) of the lamination of the next layer, to each intermediate layer (L) to be blanked in an accumulation chamber of the blanking die_j) Stacking on the laminated sheet of the next layer;

e) blanking the end layers (L) of the laminate in a closed circular configuration of the ferromagnetic core (10, 110)_M) And by laminating the end layer (L) of the sheet_M) Is coupled with a corresponding cavity (13', 14) of the lamination of the next layer, pushing it into the accumulation chamber of the cutting die;

wherein the stacked segments (S) are arranged in a closed circular configuration₁-S_N) Each of which is made of the laminate (L)₁-L_M) Forming the laminate with a recess (22, 32, 42) at one end of the yoke seat (12) of each segment and a protrusion (21, 31, 41) at the other end of the yoke seat (12) of each segment, the recess (22, 32, 42) and the protrusion (21, 31, 41) having complementary shapes and dimensions,

the method is characterized by comprising the following steps:

f) at least one first auxiliary layer (L) on the laminate₁；L_M；L_j') a raised portion (21, 41) at one end of the yoke seat (12) and a pin portion (23, 43) formed in the vicinity of the raised portion, wherein the laminated sheet forms each of the laminated segments (S)₁-S_N)；

g) Further on the first auxiliary layer (L) of the laminate₁；L_M；L_j') a recess (22, 32, 42) is punched in the other end of the yoke seat (12) opposite to the yoke seat, wherein the lamination sheet is formedEach of the laminated segments (S)₁-S_N) (ii) a And

h) at least one second auxiliary layer (L) on the laminate₂；L_M-1；L_j") an opening (33) is punched in the vicinity of a projection (31) at one end of the yoke seat (12), wherein the lamination sheet forms each lamination segment (S)₁-S_N),

Wherein the first auxiliary layer (L)₁；L_M；L_j') and the second auxiliary layer (L)₂；L_M-1；L_j") is a continuous layer in the bundle of laminates forming each of the laminated sections (S) of the core₁-S_N) And wherein the first auxiliary layer (L) of the laminate₁；L_M；L_j') of the pin portion and the second auxiliary layer (L)₂；L_M-1；L_j") of the openings (33).

2. Method according to claim 1, characterized in that said second auxiliary layer (L) is applied to the laminate₂；L_M-1；L_j") is comprised of a notch.

3. Method according to claim 1, characterized in that said first auxiliary layer (L) of the laminate is applied_j') and said second auxiliary layer (L) of the laminate_j") are arranged between intermediate layers of laminated sheets of the ferromagnetic core (10, 110) consisting of a plurality of laminated segments (S) arranged in a closed circular configuration₁-S_N) And (4) forming.

4. Method according to claim 1, characterized in that in said ferromagnetic core (10, 110) said first auxiliary layer (L) of laminated sheets is laminated₁) Said second auxiliary layer (L) being arranged as an initial layer, and as a laminate₂) An intermediate layer coupled to the laminated sheet directly above, wherein the ferromagnetic core is composed of a plurality of laminated segments (S) arranged in a closed circular configuration₁-S_N) Form a。

5. Method according to claim 1, characterized in that in said ferromagnetic core (10, 110) said first auxiliary layer (L) of laminated sheets is laminated_M) An end layer arranged as a laminate, and said second auxiliary layer (L) of the laminate_M-1) An intermediate layer coupled to the laminate sheet directly thereunder, wherein the ferromagnetic core is composed of a plurality of laminated segments (S) arranged in a closed circular configuration₁-S_N) And (4) forming.

6. The method of claim 1, wherein a plurality of first auxiliary layers and a plurality of second auxiliary layers are formed, the first and second auxiliary layers corresponding in number and being coupled, and wherein each of the first and second auxiliary layers is coupled to one of the intermediate layers of a laminate, or to the initial layer of a laminate, or to the end layer of a laminate.

7. The method of claim 1, wherein the ferromagnetic core (10, 110) is a stator core of an electric motor.

8. A ferromagnetic core (10, 110) for an electric motor, said ferromagnetic core being formed of a plurality of stacked segments (S)₁-S_N) Forming the laminated segment from a bundle of laminated sheets, the laminated segment (S) during blanking of each laminated sheet₁-S_N) Connected together to form a closed circular configuration in which each of the stacked segments (S)₁-S_N) Substantially in the shape of a circular arc with an inwardly protruding polar expansion (11) and a yoke seat (12) arranged on the outside with respect to the central axis of the ferromagnetic core (10, 110), wherein the laminations of each lamination segment are connected together by crimping sections (13), and wherein the lamination segments (S)₁-S_N) Is connected to adjacent segments along the yoke seat (12) and is capable of reciprocating rotation, wherein the ferromagnetic core (10, 110) comprises an initial layer of laminations,A plurality of intermediate layers of laminated sheets and end layers of laminated sheets, the initial, intermediate and end layers of laminated sheets being stacked together to form a plurality of laminated segments (S) of the closed circular configuration of the ferromagnetic core (10, 110)₁-S_N) And each of said stacked segments (S) forming a closed circular configuration therein₁-S_N) Has a recess (22, 32, 42) and a protrusion (21), the recess (22, 32, 42) being located at one end of the yoke seat (12) of each segment and the protrusion (21, 31, 41) being located at the other end of the yoke seat of each segment, the recess (22, 32, 42) and the protrusion (21, 31, 41) having complementary shapes and dimensions, characterized in that a first auxiliary layer (L) comprising a laminated sheet is provided₁；L_M；L_j') and a second auxiliary layer (L) of the laminate₂；L_M-1；L_j") comprising raised pins (23, 43) and recesses (22, 32, 42), said raised pins (23, 43) being located to form each stacked segment (S)₁-S_N) In the vicinity of said protrusions (21, 41) at one end of the yoke seat (12) of the laminated sheet, said recesses (22, 32, 42) being located in said first auxiliary layer (L) of the laminated sheet₁；L_M；L_j') forming each laminated segment (S)₁-S_N) Opposite ends of the yoke seat (12), and a second auxiliary layer (L) of the laminate₂；L_M-1；L_j") has an opening (33), said opening (33) being located in the vicinity of a protrusion (31) of one end of a yoke seat (12) of a lamination sheet forming each lamination segment, wherein said first auxiliary layer (L)₁；L_M；L_j') and the second auxiliary layer (L)₂；L_M-1；L_j") is each laminated segment (S) forming the ferromagnetic core₁-S_N) And said first auxiliary layer (L) of the laminate₁；L_M；L_j') the pin portion and the second auxiliary layer (L) of the laminate₂；L_M-1；L_j") of the openings (33).

9. A ferromagnetic core (10, 110) as set forth in claim 8, which is a ferromagnetic coreCharacterized in that said second auxiliary layer (L) is present in the laminate₂；L_M-1；L_j") is comprised of a notch.

10. Ferromagnetic core (10, 110) according to claim 8, characterized in that the first auxiliary layer (L) of laminate sheets_j') and said second auxiliary layer (L) of the laminate_j") is arranged between the intermediate layers of the laminated sheets of the ferromagnetic core, the ferromagnetic core being formed of a plurality of laminated segments (S) arranged in a closed circular configuration₁-S_N) And (4) forming.

11. Ferromagnetic core (10, 110) according to claim 8, characterized in that in the ferromagnetic core the first auxiliary layer (L) of laminations is laminated₁) Said second auxiliary layer (L) being arranged as an initial layer, and as a laminate₂) An intermediate layer coupled to the laminated sheet directly above, wherein the ferromagnetic core is composed of a plurality of laminated segments (S) arranged in a closed circular configuration₁-S_N) And (4) forming.

12. Ferromagnetic core (10, 110) according to claim 8, characterized in that in the ferromagnetic core the first auxiliary layer (L) of laminations is laminated_M) An end layer arranged as a laminate, and said second auxiliary layer (L) of the laminate_M-1) An intermediate layer coupled to the laminate sheet directly thereunder, wherein the ferromagnetic core is composed of a plurality of laminated segments (S) arranged in a closed circular configuration₁-S_N) And (4) forming.

13. Ferromagnetic core (10, 110) according to claim 8, wherein a plurality of first and second auxiliary layers are arranged, the number of first and second auxiliary layers corresponding and coupled, and wherein each of the first and second auxiliary layers is coupled to one of the intermediate layers of a laminate, or to the initial layer of a laminate, or to the end layer of a laminate.

14. The ferromagnetic core (10, 110) of claim 8, wherein the ferromagnetic core is a stator core of an electric motor.

Technical Field

The present invention relates to a method for manufacturing a ferromagnetic core for an electric motor, said ferromagnetic core being constituted by bundles of stacked sheets, in particular a ferromagnetic core formed by a plurality of bundles made in the form of segments mechanically separated from each other and connected to each other.

Background

Ferromagnetic cores for electric motors by stacking multiple metal laminations are known in the art. In detail, the cylindrical cores of the stator and rotor of such motors are made by punching substantially annular laminations from a foil of ferromagnetic material and by thus bundling a suitable number of laminations to obtain a core of the desired axial length.

In detail, in particular as regards the stator core, it is also known in the art to manufacture it in the form of a plurality of segments, which are formed according to a closed circular configuration and therefore assume an open rectilinear configuration, so as to facilitate the winding of the coils on the respective polar expansions. Once the winding is completed, the rectilinear arrangement must be able to be folded to assume a closed circular shape in order to be inserted in the housing of the motor or in the cylindrical housing.

Patent application EP-a1-2309621 describes a method of forming, for example, a ferromagnetic stator core for an electric motor, formed by a plurality of laminated segments punched out of foil, so as to form laminations arranged in a circular configuration, or in other words having a "closed chain" configuration. Each stacked segment has a generally circular-arc shape with inwardly projecting polar expansions and yoke seats arranged on the outside with respect to the central axis of the ferromagnetic core. The laminations of each lamination segment are connected together by a crimp. Furthermore, each layer of laminate sheet has an embossed finger portion obtained by acting a punch on one end of each yoke seat and then engaging with a cavity formed by the laminate sheet underneath itself; at the other end of the yoke seat, however, a recess is provided which allows the lamination of adjacent segments to engage with the cavity of the underlying lamination. Thus, a hinge is obtained extending substantially along the entire axial length of the core to allow reciprocal rotation between adjacent segments, with the aim of making the segments in a rectilinear configuration, the successive steps of winding the conductor coil on the polar expansions of the segments being carried out.

However, the coupling of the pin portion of the laminate to the cavity of the underlying laminate is an interference coupling, i.e. the same type of coupling occurs between the crimp portion and the corresponding cavity, in order to secure each layer of laminate to the underlying or overlying laminate. Hinges obtained with similar types of coupling along the entire axial length of the core can make rotation between the segments difficult, especially when the length of the segments is long.

Furthermore, punching the pin portions on all the laminated sheets constituting the segments reduces productivity and causes rapid wear of the punch and the corresponding die.

US2010/066193 describes a stator core formed of several stacked segments connected together according to a closed circular configuration. Each lamination segment has a generally circular arc shape, and has a polar expansion protruding inward and a yoke seat disposed on the outer side with respect to the center axis of the stator core. The stacked segments are all connected together in a closed chain configuration and therefore cannot be brought into an open straight configuration. However, each segment may rotate and translate slightly relative to the adjacent segment to move the polar expansion of the adjacent segment away from the polar expansion of the segment on which the conductor must be wound.

This document does not describe in depth a method of manufacturing a similar stator core, but specifies:

the segments comprising the yoke seat and the polar expansions are formed one after the other;

the individual segments comprising the yoke seat and the polar expansions form a circular configuration only when assembled;

each segment is formed from a specific number of laminations, in particular twelve laminations in the example, which are connected to each other by crimping in the thickness direction to form each single segment comprising a yoke seat and a polar expansion.

It is therefore evident that the manufacture of similar stator cores requires the steps of blanking and joining the laminations to form the single segments, as well as the individual steps of assembling the single segments to form the final closed-chain configuration.

Other documents, such as US2017/117761, JP2015-223060 and JP2016-077154, disclose how to assemble single individual segments one after the other to make a stator core.

Disclosure of Invention

As mentioned above, a general object of the present invention is to provide a method of manufacturing a ferromagnetic core for an electric motor formed of a plurality of segments, which can overcome the limitations of the known art.

A particular object of the present invention is to provide a method that allows manufacturing a ferromagnetic core for an electric motor in which the segments can be easily rotated with respect to each other in order to pass from a closed circular state to an open rectilinear state and vice versa.

It is another specific object of the present invention to provide a method of the above type which produces segments of ferromagnetic core having reduced reluctance compared to the prior art.

These and other objects are achieved by the present invention which relates to a method for manufacturing a ferromagnetic core for an electric motor formed of a plurality of segments according to claim 1. Further special features of the invention are set forth in the respective dependent claims.

The object of the method of the invention relates to manufacturing a ferromagnetic core for an electric motor, said ferromagnetic core being formed by a plurality of laminated segments of a bundle of laminated sheets, the laminated segments being connected together to form a closed circular configuration during blanking of each layer of laminated sheets. Each lamination segment has substantially the shape of a circular arc with inwardly projecting polar expansions and yoke seats arranged on the outside with respect to the central axis of the ferromagnetic core. The laminations of each lamination segment are joined together by crimping to form a compact lamination bundle, and at least a portion of the lamination segment is joined to an adjacent segment along the yoke seat and is capable of reciprocal rotation. The only separate segments are the first and last in the closed circular configuration.

The method comprises the following steps:

a) feeding a foil of ferromagnetic material along a blanking station and a pressing station of a blanking/pressing device;

b) forming one or more crimps and corresponding cavities by stamping on the lamination sheet of each segment;

c) blanking an initial layer of laminations in a closed circular configuration of the ferromagnetic core and pushing it into an accumulation chamber of a blanking die of said blanking/compression die apparatus;

d) blanking a plurality of intermediate plies of the laminations in a closed circular configuration of the ferromagnetic core and coupling with respective cavities of the laminations of the next layer through the raised crimps of each intermediate ply of the laminations to stack each intermediate ply blanked on the laminations of the next layer in an accumulation chamber of a blanking die of said blanking/compression die apparatus,

e) the end layers of the laminations are blanked in the closed circular configuration of the ferromagnetic core and pushed into the accumulation chamber of the blanking die by coupling the crimped portions of the projections of the end layers of the laminations with the corresponding cavities of the laminations of the next layer.

Each of the laminated segments arranged in a closed circular configuration is formed of a laminated sheet having a concave portion at one end of the yoke seat of each segment and a convex portion at the other end of the yoke seat of each segment. The recesses and protrusions have complementary shapes and dimensions.

The method according to the invention further comprises the steps of:

f) embossing a pin portion in the vicinity of a convex portion at one end of the yoke seat in at least one first auxiliary layer of the laminated sheet, wherein the laminated sheet forms each of the laminated segments;

g) further blanking a recess in the first auxiliary layer of the lamination sheet at the other end opposite the yoke seat, wherein the lamination sheet forms each of the lamination sections; and

h) an opening is punched in at least one second auxiliary layer of the lamination sheet near a projection at one end of the yoke seat, wherein the lamination sheet forms each lamination segment.

The first and second auxiliary layers are successive layers in a bundle of laminates forming each of said stacked segments of said core and wherein said pin portions of said first auxiliary layer of laminates engage with openings of the second auxiliary layer of laminates.

Still further, therefore, only one pair of auxiliary layers is sufficient to form a ferromagnetic core segment that is capable of reciprocal rotation relative to the pin portion formed by the first auxiliary layer in each segment.

The opening formed in the second auxiliary layer of the laminate consists of a notch. Advantageously, this also allows a slight translation to be achieved between the segments, facilitating the passage of the segments from the closed circular configuration to the open rectilinear configuration and vice versa.

In a possible embodiment of the method, the first auxiliary layer of laminated sheets and the second auxiliary layer of laminated sheets are arranged between intermediate layers of laminated sheets of the ferromagnetic core, the ferromagnetic core being constituted by a plurality of laminated segments arranged in a closed circular configuration.

In another embodiment of the method, the first auxiliary layer of laminations is arranged as an initial layer and the second auxiliary layer of laminations is coupled to an intermediate layer of laminations directly above it in the ferromagnetic core, wherein the ferromagnetic core is comprised of a plurality of laminated segments arranged in a closed circular configuration.

In another embodiment of the method, the first auxiliary layer of laminations is arranged as an end layer and the second auxiliary layer of laminations is coupled to an intermediate layer of laminations directly below it in the ferromagnetic core, wherein the ferromagnetic core is comprised of a plurality of laminated segments arranged in a closed circular configuration.

In other embodiments of the method, a plurality of first and second auxiliary layers are formed, corresponding in number and coupled. Each of the first auxiliary layer and the second auxiliary layer is coupled to one of the intermediate layers of laminate, or to the initial layer of laminate, or to the terminal layer of laminate.

According to the present invention, there is also provided a ferromagnetic core of an electric motor, the ferromagnetic core being formed of a plurality of laminated segments consisting of a lamination bundle, the laminated segments being connected together in a closed circular configuration during blanking of each lamination layer, wherein each of the laminated segments generally has the shape of a circular arc with an inwardly projecting polar expansion and a yoke seat arranged on the outside with respect to a central axis of the ferromagnetic core. The laminations of each lamination segment are joined together by crimps and at least a portion of the lamination segment is joined to an adjacent segment along a yoke seat and reciprocally rotatable. The ferromagnetic core includes an initial layer of laminations, a plurality of intermediate layers of laminations, and an end layer of laminations stacked together to form a plurality of stacked segments of a closed circular configuration of the ferromagnetic core.

The lamination layer forming each stacked segment arranged in a closed circular configuration has a recess at one end of the yoke seat of each segment and a protrusion at the other end of the yoke seat of each segment; the recess and the protrusion have complementary shapes and sizes. The ferromagnetic core includes a first auxiliary layer of laminations having raised pins located near the bosses forming one end of the yoke seat of the laminations of each lamination segment and recesses located at the opposite ends of the yoke seat in each lamination segment formed at the first auxiliary layer of laminations, and a second auxiliary layer of laminations having openings located near the bosses forming one end of the yoke seat of the laminations of each lamination segment. The first auxiliary layer and the second auxiliary layer of laminations are successive layers in the lamination bundle forming each stacked segment of the core, and the dowel portions of the first auxiliary layer of laminations are engaged at the openings of the second auxiliary layer of laminations.

The openings formed in the second auxiliary layer of the laminate advantageously consist of notches.

In one embodiment of the ferromagnetic core, the first and second auxiliary layers of laminations are disposed between the intermediate layers of laminations of the ferromagnetic core formed of a plurality of stacked segments arranged in a closed circular configuration.

In another embodiment of the ferromagnetic core, the first auxiliary layer of laminations is an initial layer and the second auxiliary layer of laminations is coupled to an intermediate layer of immediately overlying laminations in the ferromagnetic core formed of a plurality of stacked segments arranged in a closed circular configuration.

In another embodiment of the ferromagnetic core, the first auxiliary layer of the laminations is an end layer of the laminations and the second auxiliary layer of the laminations is coupled to an intermediate layer of the immediately underlying laminations in the ferromagnetic core formed of a plurality of stacked segments arranged in a closed circular configuration.

In other possible embodiments of the ferromagnetic core, a plurality of first auxiliary layers coupled to a corresponding number of second auxiliary layers is arranged. Each of the first and second auxiliary layers may be coupled to one of the middle layers of the laminate, or to the initial layer of the laminate, or to the end layer of the laminate.

The ferromagnetic core according to the invention is a stator core of an electric motor.

Drawings

Further characteristics and advantages of the invention will become clearer with reference to the attached schematic drawings, given below by way of illustrative description and without limitation, wherein:

figure 1 is a plan view of a ferromagnetic core for an electric motor according to a possible embodiment of the invention;

figure 2 shows a view of the lamination type of the initial layers forming the bundle of ferromagnetic cores of figure 1 in alignment;

figures 2A, 2B, 2C and 2D show some details of the lamination of figure 2;

figure 3 shows a view of the lamination type of the second layer of the bundle forming the ferromagnetic core of figure 1 in a rectilinear arrangement;

figures 3A, 3B, 3C and 3D show some details of the lamination of figure 3;

figure 4 shows a view of the lamination type of the intermediate layers forming the bundle of ferromagnetic cores of figure 1 in a rectilinear arrangement;

fig. 5 shows a view of the lamination type of the penultimate layer of the bundle forming the ferromagnetic core of fig. 1 in a rectilinear arrangement;

fig. 6 shows a view of the lamination type of the end layers forming the bundle of ferromagnetic cores of fig. 1 in alignment;

fig. 6A, 6B, 6C and 6D show some details of the lamination of fig. 6;

figures 7A, 7B and 7C are bottom plan views of some details of the ferromagnetic core of figure 1;

figures 8A, 8B and 8C are cross-sectional views of figures 7A, 7B and 7C;

fig. 9A, 9B and 9C are top plan views of some details of the ferromagnetic core of fig. 1;

fig. 10A, 10B and 10C are cross-sectional views of fig. 9A, 9B and 9C;

figure 11 shows a schematic view of a first step of the process of manufacturing a ferromagnetic core according to the invention in certain stations of a blanking/compression moulding device;

11A, 11B, 11C and 11D show some details relating to the process of FIG. 11;

figure 12 shows a schematic view of some successive steps of the process of manufacturing a ferromagnetic core according to the invention in some stations of a blanking/compression moulding device;

figures 12A and 12B show some details relating to the process of figure 12;

figure 13 shows a schematic view of some successive steps of the process of manufacturing a ferromagnetic core according to the invention in some stations of a blanking/compression moulding device;

fig. 13A, 13B, 13C, 13D and 13E show some details relating to the process of fig. 13;

figure 14 shows a schematic view of the last step of the process of manufacturing a ferromagnetic core according to the invention in some stations of a blanking/compression moulding device;

fig. 15 is a schematic view similar to fig. 14, showing an embodiment of the method according to the invention in another possible blanking/pressing device;

figure 16 shows a schematic view of another embodiment of the method according to the invention; and

fig. 17-20 are schematic cross-sectional views of other embodiments of ferromagnetic cores according to the invention.

Detailed Description

In fig. 1 there is shown a ferromagnetic core 10 manufactured according to the invention, in particular a ferromagnetic stator core for an electric motor. The ferromagnetic core provides a plurality of stacked segments S connected together₁...S_i...S_NWhich can be rotated so as to be able to switch from a closed circular configuration to an open rectilinear configuration and vice versa. Only segment S₁And S_NSimply placed in connection with each other at the joint 15 along the end with the complementary shape.

Each of the stacked segments S₁...S_i...S_NGenerally has the shape of a circular arc with an inwardly projecting polar expansion 11 and a yoke seat 12 arranged on the outside with respect to the central axis C of the ferromagnetic core 10. Each of the stacked segments S₁...S_i...S_NAre connected together by crimping portions 13.

The embodiments of ferromagnetic core 10 described herein by way of example provide an initial layer and an end layer of laminations, both provided with pins engaging in corresponding slots of adjacent lamination layers, but it will be appreciated that the number and arrangement of pins may also be different, as will be explained below.

FIG. 2 shows the initial layer L of the laminate₁I.e. the first layer formed when manufacturing the lamination bundle that will constitute the ferromagnetic core 10. As shown in fig. 2A, segment S₁Has a projection 21 at one end of the yoke seat 12 and a recess 22 at the other end. From the view of fig. 2B, a portion of the yoke seat 12 is shown, it being noted that the segment S₁On the convex partThere are no upwardly or downwardly projecting members at 21. Layer L₁Constituting the first auxiliary layer of the laminate.

As shown in fig. 2C and 2D, in the initial layer L₁Segment S of₂-S_NThe remaining laminations instead have upwardly projecting pins 23 at the convex portions 21, which pins 23 are obtained by stamping in a blanking/stamping process.

Furthermore, in the initial layer L₁Forms a cavity 14 in the laminate, which cavity 14 receives the second layer L₂And engages crimp 13 of the laminate.

Figure 3 shows the second layer L of the laminate₂The structure of (1). As shown in fig. 3A and 3B, segment S₁-S_N-1Has a convex portion 31 at one end of the yoke seat 12 and a concave portion 32 at the other end. In segment S₁-S_N-1Is formed with a notch 33 at the projection 31 of each lamination, wherein the initial layer L shown in fig. 2C and 2D₁Of the stack S₂-S_NEngages in the notch 33. Layer L₂Constituting the second auxiliary layer of the laminate.

As shown in fig. 3C and 3D, at segment S_NOf the laminate of (a) a second layer L₂But instead has no notches.

Furthermore, by punching the layer L₂The laminate of (a) obtains a downwardly projecting crimping portion 13 which is forced against the initial layer L₁The cavities 14 of the laminations are engaged. Furthermore, the stamping forms a cavity 13' in the upper part of the lamination, which will be forced into engagement with the crimp 13 of the overlying lamination layer.

FIG. 4 shows the middle layer L of the laminate_jThe structure of (1). At all segments S₁-S_NIntermediate layer L in (1)_jThe laminate of (a) is the same as the laminate shown in figures 3C and 3D.

FIG. 5 shows the penultimate layer L of the laminate_M-1The structure of (1). This structure is in common with the second layer L of FIG. 3₂The structure is identical to the segment S shown in FIGS. 3A and 3B₁-S_NIs identical to the stack of sheets of fig. 3C and 3D, and a segment S_NThe laminations of (a) are identical. Layer L_M-1Constituting the second auxiliary layer of the laminate.

FIG. 5 showsOut of the end layer L of the laminate_MI.e. the last layer formed when manufacturing the stack of laminations which will constitute the ferromagnetic core 10. As shown in FIG. 6A, segment S₁Has a projection 41 at one end of the yoke seat 12 and a recess 42 at the other end. From the view of fig. 6B showing a part of the yoke seat 12, it can be noted that the segment S₁The lamination of (a) has no upwardly or downwardly projecting pin portion at the convex portion 41. Layer L_MConstituting the first auxiliary layer of the laminate.

As shown in fig. 6C and 6D, the end layer L_MSegment S of₂-S_NThe remaining laminations instead have a downwardly projecting pin portion 43 at the convex portion 41, which pin portion 43 is obtained by stamping in a blanking/stamping process.

In addition, in the terminal layer L_MIs formed with a crimp portion 13, the crimp portion 13 being bonded to the penultimate layer L_M-1In the cavity 13' of the lamination.

The bottom plan views of fig. 7A-7C and the corresponding cross-sectional views of fig. 8A-8C show the segments S in the lower layer that make up ferromagnetic core 10 at the right and left ends 12D and 12S of yoke seat 12₁-S_NSome details of (a).

FIGS. 7A and 8A show segment S₁In which the initial layer L is projected₁The convex portion 21 and the second layer L₂And successive intermediate layers L and recesses 32_jThe recess 32.

FIGS. 7B and 8B show segment S₂-S_N-1At one end of the yoke seat 12 and by means of which the rotational coupling of the segments is achieved. The initial layer L is highlighted in the figure₁Is bonded to the second layer L₂In the notches 33.

FIGS. 7C and 8C show segment S_NAt one end of the yoke base 12, in which the initial layer L is projected₁And the second layer L and the recess 22₂Convex portion 31 and continuous intermediate layer L_jThe convex portion 31 of (a).

The top plan views of fig. 9A to 9C and the corresponding sectional views of fig. 10A to 10C show the segments in the upper layer of the laminations constituting the ferromagnetic core 10 at the right end 12D and the left end 12S of the yoke seat 12S₁-S_NSome details of (a).

FIGS. 9A and 10A show segment S₁In which the terminal layer L is projected_MThe concave portion 32 of the convex portion 41 and the penultimate layer L_M-1And the following intermediate layer L_jThe recess 32.

FIGS. 9B and 10B show segment S₂-S_N-1At one end of the yoke seat 12 and by means of which the rotational coupling of the segments is achieved. The end layer L is highlighted in the figure_MIn the penultimate layer L of the pin portion 23_M-1Is engaged by the notch 33.

Fig. 9C and 10C show a segment S at one end of the yoke seat 12_NIn which the terminal layer L is projected_MRecess 42 and penultimate layer L_M-1Convex portion 31 of (A) and the lower intermediate layer L_jThe convex portion 31 of (a).

The first step of the process of manufacturing a ferromagnetic core according to the invention, with reference to the various stations of the blanking/die assembly, is shown in figure 11, in which a foil 100 of ferromagnetic material is fed in the direction of the arrow F. As is known, a blanking/die assembly comprises two separate half-moulds, at least one of which is movable with respect to the other, which half-moulds generally extend along a succession of blanking/die stations.

Cavities 101 and 102 are blanked in pairs in a first station B1 (fig. 11B), in which position a separating cut is subsequently made to separate the laminations of two adjacent segments. Fig. 11A shows the shape of the portion removed from the foil 100.

Separation cuts 103 (fig. 11B) are formed in successive stations B2 to separate the laminations of adjacent segments. Station B2 may be in an operative or inoperative state, since separation cuts 103 only act on the initial layer L₁And a terminal layer L_MOn the stack of (a). Fig. 11C is a cross-sectional view of one of the cuts 103 of the blanking/die assembly, wherein it is possible to note the punch P1 and the extractor E1 actuated in the upper half of the blanking/die assembly and the punch P2 and the extractor E2 actuated in the lower half.

Segment S of the second layer L2₁-S_N-1Slot 33 and penultimate layer L_M-1Segment S of₁-S_N-1Is blanked in station B3, so that the punch forming the slot 33 can be selectively actuated in station B3. However, portions of foil sheet 100 are blanked to define segments S₁-S_NIs always activated in the same station B3. The shape of the portion removed to form the slot 33 is shown on a larger scale in fig. 11D, while the portion removed with broken lines in the same station B3 represents the defining segment S₁-S_NPortion 107 of (a).

Thus, the foil 100 continues at station B4-B6 shown in FIG. 12. Station B4 is a standby station in which no blanking or stamping operations are performed to allow selective actuation of the punches of the successive station B5.

Separation cuts 104 (fig. 12A) are formed in successive stations B5 to separate the laminations of adjacent segments. The station B5 may be in an active or inactive state because of the secondary level L₂Initially, then through the intermediate layer L_jExtending to the penultimate layer L_M-1The separation cuts 104 act on the laminate S₁-S_NThe above. Fig. 12B is a cross-sectional view of one of the blanking/die assemblies in the slit 104, wherein it can be noted the punch P3 and the extractor E3 actuated in the upper half of the blanking/die assembly and the punch P4 and the extractor E4 actuated in the lower half.

Like station B4, station B6 is also a standby station in which no blanking or stamping operations are performed to allow selective actuation of the punches of successive stations.

The foil 100 continues at station B7-B9 shown in FIG. 13.

In station B7, a single initial layer L is punched₁In which the second layer L is a hollow cavity 14 of the laminate₂The crimps 13 of the laminate are forced into engagement with the cavity 14. Fig. 13A shows the shape of the blanking portion. Thus, the punches performing these blanking operations are only directed at the first layer L₁Is effective as a first layer L₁A separating layer will thus be formed to separate the ferromagnetic cores which are pushed into the accumulation chamber of the cutting die of the blanking/pressing device during the final part of the process.

The central disc 108 of the laminations 100 is also blanked in the same station B7 so as to delimit the ends of the polar expansions 11 of the ferromagnetic core. Therefore, the punch performing this blanking is always in an operating state.

Segment S₂-S_NOf the laminate L₁Pin portion 23 (fig. 13B) or segment S of₂-S_NLast layer L of the laminate_MOptionally pressed in station B8. Station B8 is thus actuatable, deactivatable, or replaceable.

Punching out a layer L in a station B9₂-L_MAll laminations S of₁-S_N13 (fig. 13D and 13E). As shown in fig. 13E, the cavity 13' is formed by press-molding the crimp portion 13, and the crimp portion of the upper lamination is forcibly engaged in the cavity. In any case, since only the first layer L of the laminate has to be provided₁Forming the cavity 14, and station B9 also includes an actuatable and deactivatable punch.

Fig. 14 shows the final step of the process for manufacturing a ferromagnetic core according to the invention. Each of the laminations 110 is blanked from the foil 100 in station B10 and pushed into an accumulation chamber under the die of station B10. This allows coupling the crimping portion 13 to the first layer L by interference₁Or cavities 13' of successive laminations, to form a complete ferromagnetic core, such as that indicated by 10 in figure 1.

For example, a cutter 111 may be provided in station B11, the cutter 111 allowing the scrap of foil 100 to be reduced to small sized pieces 115.

Fig. 15 shows a further embodiment of the method according to the invention. In each blanking step of the lamination layer 110, the accumulation chamber under the die of station B10' can be rotated by a predetermined angle (arrow R). As is well known, this allows balancing the lateral thickness differences that often occur between the two sides of the foil 100.

The rotation angle depends on the number N of segments forming ferromagnetic core 10 and is a suitable fraction (one N) of the circumference angle. For example, in the embodiment described herein, in which the ferromagnetic core 10 is composed of twelve segments, the rotation angle applied to the accumulation chamber may be a minimum of 30 °, i.e. 2 pi/N, but may also be 60 ° (2 pi x 2/N), 90 ° (2 pi x 3/N), etc., so that each segment of the punched laminations 110 is correctly coupled to and accumulated with each segment of the laminations located directly below the accumulation chamber.

The rotary motion of the accumulation chamber in station B10 'can be applied, for example, by a motor (not shown) that transmits the rotary motion to the pulley 120 through a toothed belt 130, or by any transmission system capable of ensuring the necessary precision positioning of the accumulation chamber in station B10', in which the final blanking of each layer of laminations 110 takes place.

Fig. 16 schematically shows an embodiment of the method according to the invention, in which the foil 100 is punched in two staggered stations with identical punching/die arrangements. This embodiment can be used, for example, for productivity reasons, while limiting the scrap obtained as a processing residue of the foil 100. The blanking of the foil 100 can in any case also be carried out along more rows (i.e. along three or more rows) on the same foil 100, using blanking, punching and/or stamping stations of the blanking/stamping device suitably positioned staggered along adjacent rows, in order to limit as much as possible the scrap.

Fig. 17 to 20 show further embodiments of ferromagnetic cores according to the invention.

For example, ferromagnetic core 50 as shown in fig. 17 may include only a first auxiliary layer of one lamination and a second auxiliary layer of one lamination, the first auxiliary layer corresponding to end layer L of ferromagnetic core 10 described so far_MThe second auxiliary layer corresponding to layer L_M-1. Can manufacture and initiate the layer L₁Similar initial layer L without the pin portion 23₁', and an intermediate layer L_jAs is the intermediate layer of the ferromagnetic core 10.

In the same manner, the ferromagnetic core 60 as shown in fig. 18 may include only one initial layer L corresponding to the ferromagnetic core 10₁And a second auxiliary layer of only one lamination, corresponding to layer L₂. Can be made with the end layer L_MSimilar end layer L without the pin portion 43_M', whileInterlayer L_jAs is the intermediate layer of the ferromagnetic core 10.

However, the ferromagnetic core 70 of fig. 19 includes the first auxiliary layer L_j' and a second auxiliary layer L_j", the first auxiliary layer L_j' and a second auxiliary layer L_j"as an intermediate layer in a lamination bundle forming a ferromagnetic core. In this embodiment, the initial layers L1 'of the laminations are the same as the initial layers of the ferromagnetic core 50 of fig. 17, while the end layers LM' of the laminations are the same as the end layers of the ferromagnetic core 60 of fig. 18.

The ferromagnetic core 80 shown in FIG. 20 is similar to the ferromagnetic core of FIG. 19, with the auxiliary layer L_j' and L_j"in an inverted position.

Various modifications may be made to the embodiments described herein, by way of example, without departing from the scope of the invention. For example, the number of first auxiliary layers and the corresponding number of second auxiliary layers in the ferromagnetic core may also be different from what has been described so far, e.g. by combining the various embodiments of ferromagnetic cores 10, 50, 60, 70 and 80.