EP2891227A2

EP2891227A2 - Manufacturing process of tooth tip deformation of dynamo-electric machine stator

Info

Publication number: EP2891227A2
Application number: EP13766882.8A
Authority: EP
Inventors: Orlando Starke; Anderson Wolf; Heber De Carvalho Hespanhol
Original assignee: Whirlpool SA
Current assignee: Whirlpool SA
Priority date: 2012-08-31
Filing date: 2013-08-30
Publication date: 2015-07-08
Also published as: BR102012022078A2; WO2014032153A3; WO2014032153A2; CN104737420A

Abstract

The present invention relates to a method and a system of deformation of grooves of blades of stator of dynamo-electric type machines stator capable to promote a suitable opening of the housing channels (2) of the electrical conductors. More particularly, the present invention relates to a process and a system which comprise advance rods (7) radially distributed around said blade (1 ) and aligned with respective grooves formed between side flaps (5) of adjacent shoes (4), wherein the end of said advance rod (7) has a configuration appropriate for interacting with a respective rocker (8) pivoted in an articulating pin (8'), each one being provided with a deformation puncture (9) that causes the opening of the housing channels (2) of the electrical conductors; and at least one return disc (10) for driving said rockers (8) together with said punctures (9) to the initial position.

Description

Specification for "PROCESS AND SYSTEM OF DEFORMATION OF GROOVES OF DYNAMO-ELECTRIC MACHINE STATOR".

Field of the Invention

This invention is concerned with an improved process for manufacturing a dynamo- electric machine stator. More preferably, the present invention relates to a process of deformation of grooves provided on blades used for mounting the structure of an electric motor stator, this process being accomplished by an angular movement of a rocker component, which is driven by the action of at least one advance rod that moves vertically due to the hammer of a press.

The present invention further relates to the system for deformation of grooves that help manufacturing the blades used for mounting the structure of stators of dynamo-electric machines.

Background of the Invention

As is within the general knowledge of the technique, machines of the dynamo- electric type are equipment for the energy transformation, in particular, they are able to transform electrical into mechanical energy, e.g. electric motors, or vice versa, transform mechanical into electrical energy such as generators. This equipment are usually formed by fixed and movable inductive cores, being its operation based on the electromagnetic induction generated by the interaction between said inductive cores.

As should be appreciated by those skilled in the art, the fixed cores are arranged and accommodated in the body of the stator, and the movable cores are arranged in the rotor body, the interaction between these cores is able to generate a magnetic field sufficient to move the rotor and hence obtain the transformation of the electrical energy into mechanical energy.

From the constructive point of view, the dynamo-electric machine stator is mainly integrated by a metal frame or structure and a plurality of coils (electrical conductors arranged on a surround manner around shoes), wherein the coils are disposed in alignment with respect to the frame metal.

More specifically, and still from the functional point of view, the metal frame of a stator according to the conventional embodiments and belonging to the state of the art, defines radial shoes circumferentially spaced apart and circumferentially joined together through the outer ends thereof (with the inner ends spaced from each other). These shoes ultimately define structures in which electrical conductors are rolled, and the spaces between these shoes are meant to accommodate the volume formed for the accommodation of the electrical conductors.

In this sense, it is possible to note that each shoe and its respective coil conform a fixed inductive core. In the case of exclusively rotating dynamo-electric machines, the rotor (whose physical embodiment is similar to the physical embodiment of the stator) is mounted inside the stator, and because of this, the shoes of the metal frame of the stator have a length dimensioned to form an empty central space, such space intended for accommodation and positioning of the rotor.

Figure 1 shows a schematic and planned view of a blade of a dynamo-electric machine stator according to a conventional embodiment belonging to the prior art.

Based on the fundamental principles mentioned above, it is obvious to those skilled in the art that the stator and the rotor of a same dynamo-electric machine can be obtained from the same metal sheet, as the rotor has dimensions substantially equivalent to the empty space existing in the center of the stator. However, it is also within the knowledge of these skilled in the art that the handling of metal monoblock consists of complex industrial processes, which produce results of questionable quality.

In this regard, it is common to note that the metal frames of stators of dynamo- electric machines of the prior art, besides the respective metal frames of the rotors, are typically made from the junction of multiple metal strips of format equivalent to each other. An example of this embodiment can be seen in document US 2011/0127876, wherein it is illustrated and described that a single metal sheet (raw material), when subjected to a stamping process, may be used for manufacturing multiple stator blades and multiple rotor blades. It is also emphasized that the rotor blades are manufactured from the exceeding raw material obtained after stamping of the stator blades. Although the cited document US 2011/0127876 describes an example of this type of embodiment, it should be evidenced that the practice now explained is already conventional since the mid-1960s.

According to the concepts already disseminated in the current state of the art, it is also known that the area of the electrical conductors that conforms the coils of the stator comprises a feature capable of influencing the efficiency of the dynamo-electric machine. More specifically, it is known that electrical conductors of smaller area are more susceptible to the occurrence of Joule effect, besides the intrinsic limitation on the nominal value of the electric current that these conductors support. Therefore, there is an interest that electrical conductors that form the coils of the stator exhibit the largest possible area (within the needs of each project).

However, the area of the electrical conductors that conform the coils of the stator tends to be limited by characteristics of the metal frame of the stator.

In this sense, it is known that each of the shoes of the stator blade has a final end defined by two side flaps. Therefore, the area of the electrical conductors comprising the coils of the stator ends up being limited to the space existing between the side flaps of consecutive shoes, being the process of inserting the wire in the stator limited by this space between the side flaps.

So it is worth also to mention that the aforementioned space between the side flaps of consecutive shoes also comprises a feature capable of influencing the efficiency of the dynamo-electric machine, this because the higher this spacing, the higher the magnetic dispersion of the inductive core and, consequently, the higher the yield loss of the dynamo- electric machine (relationship between the amount of electrical energy transformed into mechanical energy or vice versa).

Therefore, so that a dynamo-electric machine is effective, there must be a balance between the area of the electrical conductors that form the coils of the stator and the magnetic dispersion of the inductive core provided by the space existing between the side flaps of consecutive shoes. However, achieving this balance is extremely complex.

In order to optimize these aspects, the current state of the art also presents blades of dynamo-electric machines stators whose side flaps of the shoes are subject to "motion" throughout the process for manufacturing said stator. Examples of these types of blades and / or processes are disclosed in documents PI 9702724-3, US 4176444, US 4267719 and US 6742238.

Document PI 9702724-3 describes an optimized embodiment of blade of stator of electric motor. In this embodiment, the side flaps of the shoes are able to be handled during the process for manufacturing the stator, thereby allowing the "opening" and the "closure" of the housing channels of electrical conductors. More particularly, it is noted that the "opening" and "closure" of the channels occur through the deformation of the side flaps of the shoes. The great negative aspect referring to the embodiment described in document PI 9702724-3 refers to the deformation need of the side flaps of the shoes to close and, above all, to open the channels, after all, it is extremely complex to grouping multiple blades whose side flaps of the shoes are pivoted.

Documents US 4176444 and US 4267719, both derived from a single priority, describe a method and device to conform stators of electric machines. Said method provides a series of steps that, in general, define that the blades are first stamped, and subsequently grouped, forming the metal frame of the stator. With the metal frame already conformed, the side flaps of the shoes are subjected to deformation by pressure, and once all channels are opened, the housing of the electrical conductors is performed. Then, the channels are also closed by deformation by pressure, and the method is completed. In general, the "opening" of the channels is performed in an equipment provided with a puncture where each channel is invaded by a puncture, and each of the lower ends of the shoes is supported in a sort of deformation template. The movement (from inside outwards) of the puncture tool forces the side flaps of the shoes against the template, and this cause said side flaps to assume the shape of said template. Although the matter of such documents partially solves the negative aspects existing in the matter of document PI 9702724-3, it is noted that the opening step of the channels is only viable through complex tools. Furthermore, it is also noted that all side flaps of the shoes are subjected to a uniform pressure; however, these same side flaps of the shoes have different levels of mechanical resistance, which can result in unconformities at the end of the process.

Document US 6742238 describes a manufacturing concept wherein the blades of stator are already stamped with open channels (of housing of electrical conductors), that is, the stamping mold of these blades already causes them to be made, from a single "blow" of press, with he side flaps of the shoes already "deformed." Although this concept solves many of the problems related to the conventional steps of "opening" the housing channels of electrical conductors, it is worth noting that the exceeding raw material obtained after stamping such stator blades cannot be used for making the rotor (of the same dynamo- electric machine), after all, it is extremely important that the inner diameter of the stator is equivalent to the outer diameter of the rotor, and the manufacturing concept described in document US 6742238 does not achieve this prerequisite.

Based on all the context explained above, it is evident to note that the current state of the art needs a manufacturing solution, or even, a process for manufacturing dynamo- electric machine stator free of the negative aspects explained above. The present invention arises based on this scenario.

Objectives of the Invention

So, before all the above, it is an objective of the present invention to provide a process for deformation of the slots provided in the stator blades for machines of the dynamo-electric type that promotes a proper opening of the housing channels of the electrical conductors.

It is also an objective of the present invention that the side flaps of the shoes of the slots in the blades are deformed in the stamping step itself. More particularly, through the oscillatory movement in the press and, in the sequence of the stamping and removal of the exceeding raw material for mounting the rotor.

Further, it is an objective of the present invention to provide a system for deformation of the grooves of blades for stator, said system being comprised of technical and functional characteristics able to promote the proper deformation of the side flaps of the shoes to the functional opening of the housing channels of the electrical conductors. More particularly, the system of the present invention is able to solve the drawbacks of the prior art commented above, but mainly to obtain one stator blade suitable for receiving the electrical conductors in such a way that, during the manufacturing and assembly process of the stator, it has an easy handling configuration for secure closing of said channels. Summary of the Invention

These and other objectives of the present invention are achieved by the process of deformation of grooves in stator blades of dynamo-electric machine disclosed herein. In general, this process comprises at least one stamping step of raw material for conformation of at least one blade and it is different from the other existing processes due to the fact that it forsees, after performing of said "first" step, at least one "other" deformation step of the side flaps of the adjacent shoes of the grooves of the stator blade.

According to the invention, this "other" step comprises basically the following sub- steps: at least one vertical advance movement of at least one advance rod cooperating with a set of rockers, at least one angular advance movement of a plurality of deformation punctures cooperating to said set of rockers, at least one vertical retreat movement of said advance rod promoted by at least one return mechanism, and at least one angular retreat movement of the plurality of deformation punctures to the initial positions thereof. At most, it is also worth noting that the angular advance movement of the plurality of deformation punctures is able to force the collision between each puncture with a respective adjacent side flap of the slot of the stator blade.

In this regard, and based on the preferred concepts of the present invention, it is noted that the interaction of the advance rod with the respective rockers thereof also promotes the angular movement of said rockers and, consequently, the angular advance movement of the deformation punctures. On the other hand, the interaction of the return mechanism with the respective rockers thereof also promotes the angular movement of said rockers) and hence the angular retreat movement of the deformation punctures.

Preferably, it is also noted that the vertical advance movement of the advance rod is carried out by the vertical actuation of the hammer of the stamping press of the blades. But the return mechanism is actuated by means of a return force, which can be matched to the resilient force of a spring, or even the strength of an electric actuator.

Furthermore, the present invention also relates to a system for deformation of grooves in stator blades of dynamo-electric machine, which was specially developed aiming to perform the process detailed above.

In general, said deformation system comprises in a same manufacturing plant, at least one means for stamping of raw material and conformation of at least one blade and at least one means able to deform the side flaps of the adjacent shoes of the grooves of at least one blade.

Preferably, said manufacturing plant comprises a stamping central unit integrated by at least one cutting stamping module and at least one physical collision deformation module of moving components.

According to a preferred embodiment of the present invention, that mainly composes the physical collision deformation module of moving components: at least one advance rod concentrically aligned to the at least one set of rockers, wherein said advance rod comprises one end configured to interact with a plurality of rockers arms, at least a plurality of rockers each provided with deformation puncture, each of the rocker pivotally connected to a single fixed structure and the deformation punctures being radially aligned to the position of the side flaps of the adjacent shoes of the grooves of the stator blade, and at least one return mechanism able to drive said rocker arms with said deformation punctures to the initial position.

Preferably, the interaction contact between the ends of the advance rod and said rockers is of the wedge type (which may be by a chamfered or radial area, as illustrated in the figures listed below). Also preferably, the return mechanism is connected to a system able to promote a return force.

Brief Description of the Drawings

The features, advantages and technical effects of the present invention, as outlined above, will be best understood by one skilled in the art from the following detailed description made by way of mere example, and not limitation, of a preferred embodiment, and with reference to the schematic figures attached, in which:

Figure 1 illustrates an exemplary stator blade obtained during the stamping step of raw material according to the present invention;

Figure 2 illustrates an exemplary stator blade obtained after performing the deformation process of the groove according to the present invention; and

Figure 3 illustrates an exemplary embodiment of the deformation system in accordance to the present invention.

Detailed Description of the Invention

According to the schematic figures mentioned above, in particular Figure 1 , it can be seen that the stator blade 1 obtained during the stamping step comprises a plurality of shoes 4, which are radially arranged and have, each, two side flaps 5 arranged in the inner ends thereof 4. These stator blades 1 , when properly grouped one on the other, conform the metal frame of the stator, defining two housing channels 2 for electrical conductors. Figure 2 illustrates the same stator blade 1 after the deformation process of the grooves according to the present invention. More particularly, it is observed that said side flaps 5 are deformed so as to promote the opening of the housing channel 2 to the electrical conductors (not shown).

It is then the main objective of the present invention that the "phases" of a stator blade 1 , as illustrated in Figures 1 and 2, are simultaneously obtained in a same manufacturing plant. For this purpose, it was developed the deformation process of grooves in stator blades of dynamo-electric machine, which provides at least one stamping step (A) of raw material for conformation of at least one blade 1 , following at least one deformation stage (A1 ) of the side flaps 5 of the adjacent shoes 4 grooves 4 of the stator blade 1.

More specifically, for the conformation of the openings of the housing channels 2 of the electrical conductors, said first stator blade 1 is subjected to a deformation process of the grooves that, during stamping of the raw material and conformation of the blade as illustrated by Figure 1 , is subjected to a step (A1 ) which comprises the deformation of the grooves which are formed by side flaps 5 of adjacent shoes 4 of the stator blade 1.

Said step (A1 ) comprises the following sub-steps:

(A11 ) at least one vertical advance movement of at least one advance rod 7 cooperating with a set of rockers 8;

(A12) at least one angular advance movement of a plurality of deformation punctures 9 cooperating to said set of rockers 8;

(A13) at least one vertical retreat movement of said advance rod 7; and

(A14) at least one angular retreat movement of the plurality of deformation punctures 9 to the initial positions thereof.

Basically, it is the angular advance movement of the plurality of deformation punctures 9 which ultimately forces the collision between each puncture 9 with a respective side flap 4 of the adjacent shoe 5 of the grooves of the stator blade 1.

Said advance rod 7 comprises a chamfered end capable of angularly moving a rocker 8 which is pivoted in articulating pin 8' and is provided with a deformation puncture 9 to contact said grooves of the stator blade 1. Moreover, due to the angular movement of the punctures 9 through the interaction between the end of the advance rod 7 and said rockers 8, said punctures 9 are forced to collide with a respective groove of the stator blade 1. Through this movement and collision, the opening for the housing channels 2 of the electrical conductors is formed.

Finally, after deformation of the grooves and forming the opening, there is the movement of a return disk 10 to drive said rockers 8 together with said punctures 9 to the initial position, so as to position all the tooling for a new deformation cycle of the groove of the stator blade 1.

According to a preferred embodiment of the invention, the vertical movement of the rod 7 is performed by the driving vertical movement of the stamping press of the stator blades 1 , particularly by the hammer of the press.

According to an alternative embodiment of the present invention, said return disc 10 is moved by means of a return mechanism F, which may be a spring, electric or electronic mechanism or, also, and alternatively, the press structure itself, in which case said return disk 10 is interconnected to the hammer of the press so as to be driven according to the oscillatory movement of said press.

As previously mentioned, the present invention also relates to a system for deformation of grooves in blades of dynamo-electric type machine stator, said system being comprised of at least one stamping means of raw material and conformation of a stator blade 1 , as illustrated in Figure 2, and at least one set of advance rod 7 radially distributed around said blade 1 and aligned with respective grooves, which are formed between the side flaps 5 of adjacent shoes 4.

In a preferred embodiment of the invention, the end of the advance rod 7 comprises a chamfered configuration that makes it possible to drive a respective rocker 8 pivoted in an articulating pin 8', and it is provided with a deformation puncture 9 responsible to produce the opening for the housing channel 2 of electrical conductors. Further, to promote the return movement to restart the processing cycle of deformation of the grooves, the system comprises at least one return disc 10 which leads said rockers 8 together with its punctures 9 to the initial position.

Said advance rods 7 are moved through the driving vertical movement of the stamping press of the blades 1.

According to an alternative embodiment of the present invention, said return disc 10 is moved by means of a return mechanism F, which may be a spring, electric or electronic mechanism or, even, the press structure itself, in which case said return disc 10 is interconnected to the hammer of the press, so as to be driven according to the oscillatory movement of said press.

It is important evidencing that the above description is for the sole purpose of describing in an exemplary manner some preferred embodiments of the process and system for deformation of grooves provided on stator blades, according to the present invention. Therefore, it is clear that the skilled in the art understand that many modifications, variations and constructive combinations of characteristics that perform the same function in substantially the same way to achieve the same results, are still within the protection scope defined by the appended claims.

Claims

1. Process of deformation of grooves in blades of dynamo-electric machine stator, comprising at least one raw material stamping step (A) for the conformation of at least one blade (1 ), and being characterized in that it foresees, following said step (A), at least one deformation step (A1 ) of the side flaps (5) of the adjacent shoes (4) of the grooves of the stator blade (1 ); step (A1 ) comprises, basically, the following sub-steps:

(A11 ) at least one vertical advance movement of at least one advance rod (7) cooperating with a set of rockers (8);

(A12) at least one angular advance movement of a plurality of angular deformation punctures (9) cooperating to said set of rockers (8);

(A13) at least one vertical retreat movement of said advance rod (7);

(A14) at least one angular retreat movement of the plurality of deformation punctures (9) to the initial positions thereof;

the angular advance movement of the plurality of deformation punctures (9) being able to force the collision between each puncture (9) with a respective side flap (5) of the adjacent shoe (4) of the slots of the stator blade (1).

2. Process according to claim 1 , characterized in that the interaction of the advance rod (7) with its respective rockers (8) also promotes the angular movement of said rockers (8) and, thus, the angular advance movement of the deformation punctures (9).

3. Process according to claim 1 , characterized in that the interaction of the return mechanism (10) with its respective rockers (8) also promotes the angular movement of said rockers (8) and, thus, the angular retreat movement of the deformation punctures (9).

4. Process according to claim 1 , characterized in that the vertical advance movement of the vertical rod (7) is carried out by vertical actuation of the hammer of the stamping press of the blades (1 ).

5. Process according to claim 1 , characterized in that the return mechanism (10) is driven by means of a return force (F).

6. Process according to claim 5, characterized in that the return force (F) is corresponding to the resilient force of a spring.

7. Process according to claim 5, characterized in that the return force (F) is corresponding to the strength of an electric actuator.

8. System for deformation of grooves in blades of dynamo-electric machine stator, characterized in that it comprises, in a single manufacturing unit, at least one mean for stamping the raw material and conforming at least one blade (1 ), and at least one meanable to deform the side flaps (5) of the adjacent shoes (4) of the grooves of at least one blade (1 ).

9. System according to claim 8, characterized in that said manufacturing plant comprises a stamping central unit integrated by at least one cutting stamping module and at least one physical collision deformation module of moving components.

10. System according to claim 9, characterized in that the physical collision deformation module of moving components is mainly integrated by:

at least one advance rod (7) concentrically aligned to the at least one set of rockers (8); said advance rod (7) comprising an end configured to interact with a plurality of rockers (8);

at least a plurality of rockers (8) each provided with deformation puncture (9); each of the rockers (8) being pivotally connected to a single fixed structure;

the deformation punctures (9) being radially aligned to the position of the side flaps (5) of the adjacent shoe (4) of the slots of the stator blade (1 ); and

at least one return mechanism (10) able to lead said rockers (8) with said deformation punctures (9) to the initial position.

1 1. System according to claim 8, characterized in that the contact interaction (11 ) between the ends of the advance rod (7) and said rockers (8) is of the wedge type.

12. System according to claim 8, characterized in that the return mechanism (10) is connected to a system able to promote a return force (F).