EP2891231A2

EP2891231A2 - Process of manufacturing an electric machine stator

Info

Publication number: EP2891231A2
Application number: EP13762377.3A
Authority: EP
Inventors: João Victor LINDROTH; Anderson Wolf; Evandro SPECKHAHN
Original assignee: Whirlpool SA
Current assignee: Whirlpool SA
Priority date: 2012-08-31
Filing date: 2013-08-28
Publication date: 2015-07-08
Also published as: MX2015002745A; CN104737426A; WO2014032149A2; WO2014032149A3; BR102012022081A2

Abstract

The present invention relates to a process for manufacturing stator for dynamo- electric machine that, after the conforming step of the metal frame of the stator, is free of any additional opening step of housing channels (2) of electrical conductors (3). Therefore, side flaps (5) of shafts (4) of stator blades (1) are deformed in the stamping step itself. Moreover, the process now described also provides a gauging step of side flaps (5) of shafts (4) of multiple stator blades (1), which provides the standardized circular alignment (7) of lower ends (6) of all shafts (4) of all multiple stator blades (1).

Description

Specification for: "PROCESS FOR MANUFACTURING DYNAMO-ELECTRIC MACHINE STATOR".

Field of the Invention

The present invention relates to an optimized process for manufacturing dynamo- electric machine stator.

More particularly, the present invention discloses a novel whole process for manufacturing dynamo-electric machine stator, this process being comprised by a plurality of steps which provide the change of the rolled raw material to the final formation of the stator itself.

Background of the Invention

As it is the known by those skilled in the art, dynamo-electric machines comprise machines capable of transforming electrical energy into mechanical energy (electric motor, for example) or mechanical energy into electrical energy (voltage generator, for example).

In general, the dynamo-electric machines are integrated by fixed inductive cores and moving inductive cores, and they have their functional principle based on electromagnetic induction principles, where the magnetic fields created by inductive cores are capable of generating movement in the moving inductive cores. In this regard, it is also known by the technicians skilled in the art that the fixed inductive cores are arranged in the stator, while the moving inductive cores are arranged in the rotor.

From the constructive point of view, the stator of a dynamo-electric machine is mainly integrated by a metal frame and a plurality of coils (electrical conductors arranged on a surround manner around a shaft), the coils being are arranged in alignment in relation to the metal frame.

More specifically, and still from the functional point of view, the metal frame of a stator, according to the embodiments conventional and pertaining to the current state of the art, defines radial shafts circumferentially spaced and circumferentially joined together by their upper ends (the lower ends being spaced from each other). These shafts ultimately define structures in which electrical conductors are wound, and the spaces between these shafts have the function of housing the volume formed by the electrical conductors. In this sense, it is possible to note that each shaft 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 due to this, the shafts of the metal frame of the stator have a length dimensioned to conform an empty central space, such space intended that the reception of the rotor.

Figure 1 shows a plan and schematic view of a dynamo-electric machine stator according to a conventional embodiment belonging to the current state of the art.

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

In this regard, it is common to note that the metal frames of dynamo-electric machines stators belonging to the current state of the art, beyond the respective metal frames of the rotors, are typically made from the junction of multiple metal blades of formats equivalent to each other. An example of this embodiment can be seen in the document US 201 1/0127876, wherein it is illustrated and described that a single metal blade (raw material), when subjected to a stamping process, may be used for making multiple blades of stator and multiple blades of rotor. It is also emphasized that the rotor blades are manufactured from the "waste" raw material of the stator blades. Although the cited document US 201 1/0127876 describes an example of this kind 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 conform 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 conform 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 regard, and referring to Figure 1 , it is noted that each shaft XE of the stator blade XL has a final end defined by two side flaps XAL. Therefore, the area of the electrical conductors that conform the coils of the stator ends up being limited to the space existing between the side flaps XAL of consecutive shafts XE.

So it is also worth to mention that the aforementioned space between the side flaps XAL of consecutive shaft XE 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 conform the coils of the stator and the magnetic dispersion of the inductive core provided by the space existing between the side flaps of consecutive shafts. 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 shaft are subject to "motion or warping" 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 shafts are able to be handled during the process for manufacturing stator, thereby allowing the "opening" and "closure" of the housing channels of electrical conductors. More particularly, it is noted that the "opening" and "closure" of the channels occur through the pivoting of the side flaps of the shafts. The great negative aspect referring to the embodiment described in document PI 9702724-3 refers to the pivoting need of the side flaps of the shafts to close and, above all, to open the channels, after all, it is extremely complex to grouping multiple blades whose side flaps of the shafts are pivoted.

Documents US 4176444 and US 4267719, both derived from a single priority, describe a method and apparatus 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 shafts are subjected to deformation by pressure, and once all channels are opened, the housing of the electrical conductors is performed. Then, the channels are closed also by deformation by pressure, and the method is completed. In general, the "opening" of the channels is performed in a puncture device, where each channel is invaded by a punch tool, and each of the lower ends of the shafts is supported in a sort of template deformation. The movement (from inside outwards) of the puncture tool forces the side flaps of the shafts against the template, and this cause said side flaps to assume the shape of said template. Although the matter of documents US 4176444 and US 4267719 partially solves the negative aspects existing in the matter of document PI 9702724-3, it should be 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 shafts are subjected to an uniform pressure, however, these same side flaps of the shafts have different levels of mechanical resistance, which can result in final unconformities.

Document US 6742238 describes a manufacturing concept wherein the blades of stator are already stamped with open channels (for housing electrical conductors), that is, the stamping mold of these blades already causes the same to be made, from a single "blow" of press, with the side flaps of the shafts already "deformed." Although this concept solves many of the problems related to conventional steps of "opening" the housing channels of electrical conductors, it is worth noting that the "waste" of these 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 equal 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

Thus, it is one of the objectives of the present invention to provide a process for manufacturing dynamo-electric machine stator that, after the conforming step of the stator blades, is free of any kind of additional step of opening the housing channels of electrical conductors, and which still presents "waste" capable of conforming rotors to be used in the same dynamo-electric machine.

It is also an objective of the invention that the side flaps of the shafts of the blades are deformed in the stamping step itself. In this regard, it is also an objective of the invention that said lateral flaps of the shafts are functionally deformed only after removal of the "waste" to be used for conforming the rotor of the dynamo-electric machine.

It is another objective of the subject invention to provide a process for manufacturing dynamo-electric machine stator whose manufactured stator has fixed inductive cores with substantially equivalent electromagnetic fields. Therefore, it is also one of the objectives of the invention that the process for manufacturing dynamo-electric machine stator is composed by a step specially dedicated to the final finishing of the stator.

Summary of the Invention

These and other objects of the invention now disclosed are fully achieved by means of the process for manufacturing dynamo-electric machine stator disclosed herein, which comprises at least one stamping step of raw material, at least one grouping step of multiple stator blades, at least one conforming step of the inductive cores in the housing channels of electrical conductors, and at least one closing step of the housing channels of electrical conductors. Said process for manufacturing dynamo-electric machine stator according to the present invention further provides at least one deformation sub-step of the side flaps of the shafts of stator blade and at least one gauging step of the side flaps of the shafts of the multiple stator blades. It is worth noting that the deformation sub-step of the side flaps of the shafts of the stator blade is performed during the stamping step of the raw-material. On the other hand, the gauging step of the side flaps of the shafts of the multiple stator blades is performed after the closure step of the housing channels of electrical conductors.

In accordance with the principles and objectives of the present invention, each stator blade is individually subjected to the deformation sub-step of the side flaps of the shafts of the stator blade.

Preferably, the deformation sub-step of the side flaps of the shafts of the stator blade comprises a last sub-step of the stamping step of raw-material. In this regard, by the end of the stamping step of raw-material, there are obtained stator blades which, when grouped, define housing channels of electrical conductors previously opened.

Also according to the principles and objectives of the present invention, the gauging step of the side flaps of the shafts of the multiple stator blades provides the standardized circular alignment of all the shafts of all the multiple stator blades.

Also preferably, the gauging step of the side flaps of the shafts of the multiple stator blades comprises a step of fine tuning through controlled physical deformation, which is, also preferably, the final step of the process for manufacturing dynamo-electric machine stator.

Brief Description of the Drawings

The present invention is explained in detail based on the figures listed below, which are:

Figure 1 illustrates one embodiment of stator blade of dynamo-electric machine according to the concepts already provided by the current state of the art;

Figure 2 illustrates in schematic form the flow chart of the process for manufacturing dynamo-electric machine stator according to the present invention;

Figure 3 illustrates an example of stator blade obtained after conclusion of the stamping step of raw material according to the present invention, and

Figure 4 illustrates a schematic section of the stator obtained after conclusion of the gauging step of the side flaps of the shafts of the stator according to the present invention.

Detailed Description of the Invention

As previously described, it is extremely interesting that the rotor and stator of a same dynamo-electric machine have their metallic frames manufactured from a same "source" of raw-material. In this sense, and from the manufacturing point of view, it is therefore extremely interesting that a same metal laminate is used both for manufacturing the rotor blades and for manufacturing the stator blades.

In this sense, and knowing that there must be a minimum clearance space between the rotor and the stator of a dynamo-electric machine, it is easy to see why the side flaps of the shafts of the stator blades are manufactured in a "non-deformed" manner, that is, they are made in such a way that, when grouped (and conforming, effectively, the metal frame of the stator), they have their housing channels of electrical conductors "closed".

This "closed" configuration of the housing channels, where the side flaps of two consecutive shafts hold a minimal distance between each other, is extremely interesting from the electromagnetic point of view, however, this same "closed" configuration turns out to limit the area of the electrical conductors to be housed (rolled and / or coiled) in the housing channels.

Thus, most of the known processes of manufacturing stators (or blades of stators) provides a step specially dedicated to the "opening" of these housing channels, and another step specifically dedicated to the "closure" of these channels.

Also in relation to the practices already known, we note that the "opening" of the channels can be performed before or after the grouping of the blades, however, in any of these cases, the demand for a stage specially dedicated to the "opening" of the channels is still observed. This means that are machinery employees specially dedicated to this task ("opening" of the housing channels of electrical conductors).

And it is in this aspect that the present invention differentiates, after all, it is provided and detailed herein a process for manufacturing dynamo-electric machine stator that, after the conforming step of the stator blades (stamping step), is free from any kind of additional stage of "opening" of the housing channels of electrical conductors.

In this way, the stator blade obtained at the end of the stamping step is equivalent to the exemplification of Figure 3, where there is illustrated a stator blade 1 provided with a plurality of shafts 4, which are radially arranged and have each two side flaps 5 arranged in his lower ends 6. These stator blades 1 , when properly grouped, conform the metal frame of the stator, defining housing channels 2 for electrical conductors 3 (as shown in Figure 4). Notably, the fundamental concept of this type of blade, as well as the physical embodiment illustrated in Figure 3, is within the knowledge of those skilled in the subject.

Anyway, and so that the proposal of the present invention (exemption from any kind of additional step of "opening" of the housing channels after the stamping step) is reached, the process disclosed herein provides, in addition to conventional steps, a new sub-step and an novel final step.

More specifically, there is disclosed a process for manufacturing dynamo-electric machine stator comprised the following steps:

Stamping step A of raw material, which also provides a deformation sub-step A1 of the side flaps 5 of the shafts 4 of the stator blade 1 ;

Grouping step B of multiple stator blades 1 ;

Conforming step C of the inductive cores (or coils) in the housing channels 2 of electrical conductors 3; Closure step D of housing channels 2 of electrical conductors 3; and Gauging step E of side flaps 5 of shafts 4 of the multiple stator blades 1.

One of the merits of the present invention is directly related to the existence of the sub-step A1 , which occurs within the stamping tool.

Then it is worth being emphasized that said stamping step A of raw material can provide many conventional sub-steps (removal of the portion to be used for manufacturing the rotor blade, definition of alignment points, definition of the area of the housing channels 2, among others), and irrespective of the number thereof, be complemented by the sub-step A1.

Said sub-step A1 consists, in general, of the simultaneous physical deformation of the side flaps 5 of the shafts 4 of a stator blade 1. The means used to cause this simultaneous physical may comprise several and already known means, provided that functionally aggregated to the machinery.

Regardless of the means itself, it is important evidencing that each stator blade 1 is individually subjected to the sub-step A1 , and preferably, the sub-step A1 comprises the last sub-step of step A.

Sub-step A1 allows that, at the end of step A, there are obtained stator blades 1 which, when grouped, define housing channels 2 of electrical conductors 3 previously opened. Therefore, the first objective of the present invention (process for manufacturing dynamo-electric machine stator that, after the conforming step of the stator blades (stamping step), is free of any kind of additional "opening" step of the housing channels of electrical conductors) is fully achieved.

As described above, the process itself is also composed by other steps. At least from the conceptual point of view, it is noted that steps B, C and D already comprises the current state of the art. Thus, there is no need to describe them in details. Anyway, at the end of steps B, C and D, it is obtained a substantially conventional dynamo-electric machine stator and, therefore, functional.

However, it is noted that step D (where it is performed the closure of housing channels 2 of electrical conductors 3 through physical deformation of side flaps 5 of shafts 4 of the metal frame of the stator) is not always able to provide a ideal "finishing" to lower ends 6 of all shafts 4 of all multiple stator blades 1 , preventing the decrease of the radial clearance between stator and rotor that is critical for the increase of the driving electric efficiency.

The lack of this ideal finishing causes the "inside" of the stator to present a "roughness" capable of rubbing with the rotor of the dynamo-electric machine, jeopardizing the performance thereof.

In this context, it is another merit of the present invention to disclose the gauging step E of side flaps 5 of shafts 4 of multiple stator blades 1. In general, the aforementioned step E consists of the standardized circular alignment 7 of lower ends 6 of all shafts 4 of all multiple stator blades 1. This "circular alignment" is schematically illustrated in figure 4 by means of the dashed circumference and also indicated by reference 7.

This standardized circular alignment is essentially performed through the controlled physical deformation (of fine tuning) of side flaps 5 of shafts 4 of multiple stator blades 1.

The means used to cause this controlled physical deformation may comprise various and already conventional means, provided that they do not involve any type of chopping wear (friction) or the like.

Besides solving the possible problems of friction between rotor and stator, the aforementioned step E also ensures the inductive cores of the stator with substantially equivalent electromagnetic fields, since step E ensures that all housing channels 2 of electrical conductors 3 have a standardized "closure". Thus, the second major objective of the present invention is also achieved.

Having illustrated schematic examples of results achieved by the present invention as well as preferred embodiments of certain aspects of the process, it should be understood that the scope of the invention covers other possible conventional variations to those skilled in the art, said scope of the present invention being solely limited by the content of the claims, including herein all possible equivalent means.

Claims

1. Manufacturing process for dynamo-electric machine stator, comprising:

at least one step (A) of stamping the raw material;

at least one step (B) of grouping multiple stator blades (1);

at least one step (C) of conforming the inductive cores in the housing channels (2) of electrical conductors (3);

at least one step (D) of closure the housing channels (2) of electrical conductors (3), and

characterized in that it further comprises:

at least one sub-step (A1) of deformation the side flaps (5) of shafts (4) of stator blade (1); said deformation sub-step (A1) being executed during the step (A) of stamping the raw-material; and

at least one step (E) of gauging the side flaps (5) of shafts (4) of multiple stator blades (1); said gauging step (E) being performed subsequently to closure step (D) of the housing channels (2) of electrical conductors (3).

2. Process according to claim 1 , characterized in that each stator blade (1) is individually subjected to deformation sub-step (A1) of side flaps (5) of shafts (4) of stator blade (1).

3. Process according to claim 1 , characterized in that the deformation sub-step (A1) of side flaps (5) of shafts (4) of stator blade (1) comprises the last sub-step of stamping step

(A) of raw material.

4. Process according to claim 1 , characterized in that at the end of stamping step (A) of raw material there are obtained stator blades (1 ) which, when grouped, define housing channels (2) of electrical conductors (3) previously opened.

5. Process according to claim 1 , characterized in that gauging step (E) of side flaps

(5) of shafts (4) of multiple stator blades (1 ) provides a standardized circular alignment (7) of lower ends (6) of all shafts (4) of all multiple stator blades (1).

6. Process according to claim 1 , characterized in that gauging step (E) of side flaps (5) of shafts (4) of multiple stator blades (1) comprises a fine tuning step through controlled physical deformation.

7. Process according to claim 1 , characterized in that gauging step (E) of side flaps (5) of shafts (4) of multiple stator blades (1) comprises the final step of the process for manufacturing dynamo-electric machine stator.