WO2014032148A2

WO2014032148A2 - Process and system for deforming stator slots of a dynamo-electric machine

Info

Publication number: WO2014032148A2
Application number: PCT/BR2013/000331
Authority: WO
Inventors: André Lucas MERINI; Anderson Wolf; Tarcisio João GROTT
Original assignee: Whirlpool S.A.
Priority date: 2012-08-31
Filing date: 2013-08-28
Publication date: 2014-03-06
Also published as: BR102012022075A2; CN104756376A; EP2891230A2; MX2015002744A; WO2014032148A3

Abstract

The present invention refers to a process and a system for deforming the slots of stator blades of dynamo-electric machines which are capable of promoting an appropriate opening for the accommodating channels (2) of the electrical conductors. More particularly, the present invention refers to a process and a system which comprise a set of extending wedges (7) that are radially distributed around said blade (1) and aligned with the corresponding slots formed by the side flaps (5) of adjacent teeth (4), wherein the end of each extending wedge (7) has a profile to interface with a corresponding linear slide (8), each of them being provided with a deforming punch element (9) which causes the opening of the accommodating channels (2) of the electrical conductors; and at least a set of returning rods (10) to conduct said linear slides (8) to their initial position.

Description

"PROCESS AND SYSTEM FOR DEFORMING STATOR SLOTS OF A DYNAMO- ELECTRIC MACHINE"

Field of the Invention

The present invention refers to an optimized process for producing a stator of a dynamo-electric machine. More preferably, the present invention refers to a process for deforming slots that are provided in blades utilized for the production of a stator of an electric motor, wherein said process is carried out by radially moving a punch element, which is guided by the action of some wedges that are activated by the vertical movement of the hammer of a mechanical press.

Moreover, the present invention refers to a system for deforming slots that take part in the manufacture of blades used for producing stators of dynamo-electric machines.

Background of the Invention

It is a general knowledge of the art that dynamo-electric machines are equipments destined to energy transformation, in special, they are capable of converting electrical energy into mechanical energy, for example, electric motors, or vice versa, converting mechanical energy into electrical energy, such as generators. These equipments are normally formed by movable and fixed inductive cores, wherein its functioning is based on the electromagnetic induction generated due to the interaction between said inductive cores.

As can be appreciated by the skilled in the art, the fixed cores are arranged and accommodated in the stator body, and the movable cores are arranged in the rotor body, the interaction between said cores is capable of generating a magnetic field that is enough to set the rotor in motion and, consequently, obtain the transformation of electrical energy into mechanical energy.

As a construction point of view, the stator of a dynamo-electric machine is fundamentally integrated by a metal frame and a plurality of coils (electrical conductors which are wound around a tooth), wherein said coils are arranged in an aligned way in relation to the metal frame.

More specifically, and also as a functional point of view, the metal frame of a stator, according to the conventional constructions of the prior art, defines radial teeth that are circularly spaced one from the other, and circumferentially attached one to the other by their upper ends (wherein the lower ends are spaced one from the other). These teeth define, as a consequence, structures around which the electrical conductors are wound, and the gaps between said teeth have the function of accommodating the volume formed by the electrical conductors.

In this sense, it is possible to observe that each tooth and its corresponding coil form a fixed inductive core.

In exclusively rotational dynamo-electric machines, the rotor (whose physical construction is similar to the physical construction of the stator) is assembled in the interior of the stator, and as a consequence, the teeth of the stator metal frame have a length that is sized so as to form a central gap, said gap being used to accommodate and locate the rotor.

Figure 1 illustrates a schematic and upper view of a stator blade of a dynamo- electric machine in accordance with a conventional construction of the prior art.

With basis on the above-mentioned fundamental principals, it is obvious for a skilled in the art that the stator and the rotor of the same dynamo-electric machine can be obtained from the same metal plate, as rotor size is substantially equivalent to the central gap of the stator. However, as also already known by the skilled in the art, handling metal blocks includes complex industrial processes, which generate results of dubious quality.

In this sense, it is common to observe that stator metal frames of dynamo-electric machines of the prior art, besides their corresponding rotor metal frames, are normally produced by attaching multiple metal blades of equivalent sizes. One example of this construction can be noted in document US 2011/0127876, wherein it is illustrated and described a single metal plate (raw material), which, when subjected to a stamping process, can be utilized for producing multiple blades of a stator and multiple blades of a rotor. It is also emphasized that the rotor blades are produced by utilizing spare parts of raw material, which are obtained after stamping the stator blades. Although said document US 2011/0127876 describes one example of this kind of construction, it shall be evidenced that the instantly described practice has been considered conventional since the 1960's.

According to the widely spread concepts related to the prior art, it is also known that the area of the electrical conductors, which form the coils of the stator, comprises a feature that is capable of influencing the efficiency of the dynamo-electric machine. More specifically, it is known that electrical conductors of smaller area are more subjected to the occurrence of joule effect, besides the intrinsic limitation related to the nominal value of the electric current that these conductors support. Therefore, there is the interest of developing electrical conductors, which form the coils of the stator, presenting the greatest possible area (respecting the requirements of each design).

However, the area of the electrical conductors which form the coils of the stator tends to be limited by the features of the stator metal frame.

In this sense, it is known that each tooth of the stator blade has a final end defined by two side flaps. Therefore, the area of the electrical conductors, which compose the coils of the stator, is limited by the gap that exists between the side flaps of consecutive teeth, wherein the process of inserting the wire into the stator is limited by such gap between the side flaps.

It shall be further cited that said gap between the side flaps of consecutive teeth also comprises a feature capable of influencing the efficiency of the dynamo-electric machine. This is due to the fact that the greater is the spacing, the greater the magnetic dispersion of the inductive core and, consequently, the greater the losses of the dynamo-electric machine (in relation to the amount of electrical energy converted into mechanical energy, or vice versa).

Therefore, in order to provide an efficient dynamo-electric machine, it shall be considered a balance between the area of the electrical conductors, which form the coils of the stator, and the magnetic dispersion of the inductive core that is promoted by the gap between the side flaps of consecutive teeth. However, the obtainment of such balance is extremely complex.

In order to optimize these aspects, the prior art further presents stator blades of dynamo-electric machines whose side flaps of the teeth are susceptible of "motion" during the process for producing the cited stator. Examples of such blades and/or processes are described in documents BR 9702724, US 4176444, US 4267719, and US 6742238.

Document BR 9702724 describes an optimized construction of a stator blade of an electric motor. In this construction, the side flaps of the teeth are able to be adjusted during the process for producing the stator, enabling, therefore, the "opening" and "closure" of the accommodating channels of the electrical conductors. More particularly, it is noted that the "opening" and "closure" of such channels occurs by deforming the side flaps of the teeth. The main negative aspect related to the construction described in document BR 9702724 refers to the need of deforming the side flaps of the teeth to not only close but also to open the channels, since it is verified that it is extremely complex to group together multiple blades whose side flaps of the teeth are pivoted.

Documents US 4176444 and US 4267719, which are both included in a single priority, describe a method and a device to form stators of electrical machines. The cited method provides several steps which define, in general, that the blades are firstly stamped and subsequently grouped together, forming the metal frame of the stator. Once the metal frame is formed, the side flaps of the teeth are subjected to pressure deformation and, since all channels are open, it is carried out the arrangement of the electrical conductors. Afterwards, the channels are closed by pressure deformation, and the method is concluded. In general, the "opening" of the channels is carried out in an apparatus comprising a punch element wherein each channel is invaded by a punch element, and each lower end of the teeth is supported in a type of deforming die. The movement (from inside to outside) of the punch element forces the side flaps of the teeth against the pattern and, as a consequence, the cited side flaps takes the shape of the pattern.

Although the subject matter of those documents of the prior art partially solves the negative aspects that exists in the subject matter of document BR 9702724, it is noted that the step of opening the channels is only possible by utilizing complex tools. Moreover, it is further verified that all the side flaps of the teeth are subjected to a uniform pressure; however, the same side flaps of the teeth have different proportions of mechanical resistance, what may cause flaws in the end of the process.

Document US 6742238 describes a mechanical concept wherein the stator blades are already stamped with opening channels (for accommodating the electrical conductors), i.e. the stamping pattern of such blades causes their production by a single "press", including the "deformation" of the side flaps of the teeth. Although this concept solves the major problems related to the conventional steps of "opening" the accommodating channels of the electrical conductors, it remains to note that the spare part of the raw material obtained after the stamping process of such stator blades cannot be used for the production of the rotor (of the same dynamo-electric machine), since it is extremely important to develop an internal diameter for the stator that is equivalent to the external diameter of the rotor, and the mechanical concept described in document US 6742238 does not achieve such requirement.

With basis on the foregoing, it remains evident that the prior art lacks a mechanical solution, or even a process for producing a stator of a dynamo-electric machine free of the above-mentioned negative aspects. So, the present invention aims to bring the solution.

Objectives of the Invention

Thus, one of the objectives of the present invention is to present a process for deforming the slots of stator blades of dynamo-electric machines which promotes an appropriate opening for the accommodating channels of the electrical conductors.

It is also one of the objectives of the present invention that the teeth side flaps of the blade slots are deformed during the proper stamping step. More particularly, by the oscillation of the mechanical press and subsequent to the step of stamping and removing the "waste" for the assembly of the rotor.

Another objective of the present invention is the provision of a system for deforming the blade slots of a stator, wherein said system is capable of promoting the appropriate and functional deformation of the accommodating channels of the stator electrical conductors. More particularly, the system of the present invention is capable of solving the above- mentioned flaws of the prior art references and, mainly, obtaining a stator blade that is appropriate for accommodating the electrical conductors in such a way that, during the assembly and production of the stator, this presents a construction that is easy to adjust for the safe closure of said channels.

Summary of the Invention

These and other objectives of the present invention are achieved by the instantly revealed process of deforming the slots in stator blades of a dynamo-electric machine. In general, this process comprises at least one "first" step of stamping the raw material to form at least one blade, and it is different from the prior art processes because it provides, subsequent to said "first" step, at least "another" step of deforming the side flaps of the teeth that are adjacent to the slots of the stator blade.

According to the present invention, this "another" step fundamentally comprises the following sub-steps: at least one vertical forward movement of at least one extending wedge cooperated with a plurality of linear slides; at least one radial forward movement of punch elements cooperated with said linear slides; at least one vertical backward movement of at least one returning rod cooperated with a plurality of linear slides; and at least one radial backward movement of punch elements to their initial position. Additionally, it shall be detached that the radial forward movement of punch elements is capable of forcing the impact between each punch element and a corresponding tip of the tooth that is adjacent to the slots of the stator blade, achieving, therefore, the main objectives of the present invention.

In this sense, and with basis on the preferable concepts of the present invention, it is verified that the interaction between the extending wedges with their corresponding linear slides further promotes the linear displacement of said linear slides and, consequently, the radial forward movement of the punch elements. On the other hand, the interaction of the returning rods with their linear slides further promotes the linear displacement of said linear slides and, consequently, the radial backward movement of the punch elements. It shall be further mentioned that, in the "third" sub-step, the extending wedges are inclined to return to their initial position.

Preferably, and in order to ensure the compliance of the process, it is further noted that the extending wedges and the returning rods effectuate a cooperative movement. However, and optionally, this movement can be independent. In this case, it is noted that the consequent movement of the linear slides causes a forced displacement of the returning rods, which are also moved by means of an independent backward mechanism.

Additionally, the present invention further refers to a system of deforming slots in stator blades of a dynamo-electric machine, which was especially developed so as to carry out the above-detailed process.

In general, the cited system of deforming comprises, in the same mechanical unit, at least one means of stamping the raw material and forming at least one blade and at least one means of deforming the side flaps of the teeth that are adjacent to the slots of at least one blade. Preferably, the cited mechanical unit comprises a stamping central which is composed by at least one cut stamping module and at least one deformation module considering the physical impact of the movable components.

According to a preferable embodiment of the present invention, the cited deformation module by physical collision of movable components is basically composed by: at least one set of extending wedges radially arranged; at least one set of returning rods radially arranged; and at least one set of linear slides cooperated with said set of extending wedges and returning rod. Each linear slide further comprises at least one deforming punch element capable of deforming the side flaps of the teeth that are adjacent to the slots of at least one blade by physical impact deformation.

In this sense, the set of extending wedges is capable of promoting the linear movement of the set of linear slides. Moreover, the set of the returning rods are also capable of promoting the linear movement of the linear slides.

Preferably, the interactions between the linear slides and their corresponding extending wedges and returning rods are promoted by the wedge configuration of the corresponding contact ends of such components.

More preferably, it is verified that the extending wedges and the returning rods are simultaneously actuated by a hammer of a mechanical press.

Optionally, the returning rods are actuated by a returning mechanism which may comprise a spring-type or an electromechanical- type backward mechanism.

Short Description of the Drawings

The features, advantages and technical effects of the present invention, as previously mentioned, are better understood by a skilled in the art considering the following detailed description, which is not limited, but merely exemplified by a preferable embodiment that is referenced by the appended schematic figures, wherein:

Figure 1 illustrates an example of a stator blade that is obtained during the stamping process of the raw material, in accordance with the present invention;

Figure 2 illustrates an example of a stator blade that is obtained after the process of deforming the slot, in accordance with the present invention;

Figures 3, 4, and 5 illustrate, in a schematic way, a first option of the process and system, in accordance with the present invention;

Figures 6, 7, and 8 illustrate, in a schematic way, a second option of the process and system, in accordance with the present invention.

Detailed Description of the Invention

According to the above-mentioned schematic figures, in particular Figure 1 , it is verified that the blade of the stator 1 , which is obtained during a stamping step, comprises a plurality of teeth 4 that are radially arranged, and each of them presents two side flaps 5 arranged in its internal ends 4. These blades of the stator 1 , when properly grouped one over the other, form the metal frame of the stator, defining accommodating channels 2 for electrical conductors. Figure 2 illustrates the same blade of the stator 1 after the deforming process of the slots, in accordance with the present invention. More particularly, it is noted that said side flaps 5 are deformed so as to promote the opening of the accommodating channels 2 for the electrical conductors (not illustrated). So, the main objective of the present invention is to obtain simultaneously, and in the same mechanical unit, the "phases" of a stator blade 1 , as illustrated in figures 1 and 2. Thus, it has been developed a process for deforming slots in stator blades of dynamo-electric machines, which provides at least one step (A) of stamping the raw material so as to form at least one blade 1 , subsequently, at least one step (A1) of deforming the side flaps 5 of the teeth 4 that are adjacent to the slots of the stator blade 1.

More specifically, in order to form the openings of the accommodating channels 2 of the electrical conductors, said stator blade 1 is subjected to a process for deforming the slots that, subsequent to stamping the raw material and forming the blade as illustrated in Figure 1 , is subjected to a step (A1) which comprises the vertical movement of at least one set of extending wedges 7 radially arranged around said stator blade 1 and aligned with the corresponding slots that are formed by the side flaps 5 of the adjacent teeth 4.

Thus, it can be affirmed that said step (A1) refers to the step which is responsible for promoting the deformation of the side flaps 5 of the teeth 4 that are adjacent to the slots of the stator blade 1 , and comprises the following sub-steps:

(A11) at least one vertical forward movement of at least one extending wedge 7 cooperated with a plurality of linear slides 8;

(A12) at least one radial forward movement of punch elements 9 cooperated with said linear slides 8;

(A13) at least one vertical backward movement of at least one returning rod 10 cooperated with a plurality of linear slides 8; and

(A14) at least one radial backward movement of punch elements 9 to their initial position.

Fundamentally, the radial forward movement of the punch elements 9 forces the impact between each punch element 9 with a corresponding tip 5 of the tooth 4 that is adjacent to the slots of the stator blade 1.

The cited extending wedge 7 interacts with a corresponding linear slide 8, each of them being composed by a deforming punch 9 to contact said slots of the stator blade 1.

Moreover, due to the radial movement of the punch elements 9 by the interaction between the end of the extending wedges 7 and the cited linear slides 8, the cited punch elements 9 are forced to collide with a corresponding slot of the stator blade 1. Such movement and impact causes the opening (a) for the accommodating channels 2 of the electrical conductors.

Finally, after deforming the slots and forming the opening, there is a vertical movement of a set of returning rods 10 to conduct said linear slides 8 to their initial position, in order to arrange the tools for a new cycle of deforming the slot of the stator blade 1.

According to a preferable embodiment of the present invention, the vertical backward and forward movement of the set of extending wedges 7 occurs due to the vertical movement for activating the mechanical press of stamping the stator blades 1.

In a preferable embodiment, the interaction of the linear slide 8 with the returning rod 10 is obtained as a result of a wedge configuration of the corresponding contact ends. This configuration ensures the horizontal and radial movement of the punch elements 9, in a safe and appropriate manner, to promote the deformation of the slots that are formed by the side flaps 5.

According to an alternative embodiment of the present invention, said returning rod 1 is moved by means of a backward movement F, which can be a spring, a electric-electronic mechanism or the proper structure of the mechanical press, wherein, in this case, said returning rod 10 is directly or indirectly connected to the upper base 3 of the mechanical press (or even to the upper base of the tool that is fixed to the mechanical press), so as to be activated in accordance with the oscillation of the cited mechanical press.

As previously mentioned, the present invention further refers to a system for deforming slots in stator blades of dynamo-electric machines, wherein said system comprises at least one means of stamping the raw material and forming a stator blade 1 , such as illustrated in figure 2, and at least one set of extending wedges 7 radially arranged around said blade 1 and aligned with the corresponding slots, which are formed by the side flaps 5 of the adjacent teeth 4.

In a preferable embodiment of the present invention, the end of each extending wedge 7 comprises a profile to interface with a corresponding linear slide 8 which is composed by a deforming punch element 9 responsible for producing the opening (a) for the accommodating channel 2 of the electrical conductors. Moreover, in order to promote the backward movement to restart the cycle of processing the deformation of the slots, the system comprises at least one set of returning rods 10 that conduct the cited linear slides 8 to the initial position.

The cited extending wedges 7 are moved as a result of the vertical movement for activating the mechanical press of stamping the blades 1.

More particularly, in order to promote the horizontal and radial movement of the punch elements 9 against the slots of the stator blade 1 , the contact ends of the linear slide 8 which interacts with the returning rod 10 and the extending wedge 7 are configured in the form of a wedge; thus, upon moving the extending wedge 7 or the returning rod 10, the linear slide 8 moves to promote the openings (a) for the accommodating channels of the electrical conductors.

According to an alternative embodiment of the present invention, said returning rod

10 is moved by means of a backward mechanism F, which can be a spring, a electric- electronic mechanism or the proper structure of the mechanical press, wherein, in this case, said returning rod 10 is connected to the upper base 3 of the mechanical press (or even to the upper base of the tool that is fixed to the mechanical press), so as to be activated in accordance with the oscillation of the cited mechanical press.

It is important to emphasize that the present specification has the unique objective of describing, in an exemplified manner, some of the preferable embodiments of the process and system for deforming slots of stator blades, in accordance with the present invention. Therefore, it is clear for a skilled in the art that several constructive modifications, changes and combinations with features that apply the same function, substantially by the same form, to achieve the same results are within the scope of protection, which is defined by the appended claims.

Claims

1. A process for deforming slots in stator blades of a dynamo-electric machine, comprising at least one step (A) of stamping the raw material to form at least one blade (1), characterized in that it promotes, subsequent to said step (A), at least one step (A1) of deforming the side flaps (5) of adjacent teeth (4) of the slots of the stator blade (1); said step (A1) fundamentally comprising the following sub-steps:

(A11) at least one vertical forward movement of at least one extending wedge (7) cooperated with a plurality of linear slides (8);

(A12) at least one radial forward movement of punch elements (9) cooperated with said linear slides (8);

(A13) at least one vertical backward movement of at least one returning rod (10) cooperated with the plurality of linear slides (8);

(A 4) at least one radial backward movement of punch elements (9) to their initial position;

the radial forward movement of punch elements (9) being able to force the impact between each punch element (9) and a corresponding side flaps (5) of the tooth (4) that is adjacent to the slots of the stator blade (1).

2. The process of claim 1 , characterized in that the interaction between the extending wedges (7) and their corresponding linear slide (8) further promotes the linear displacement of said linear slides (8) and, consequently, the radial forward movement of punch elements (9).

3. The process of claim 1 , characterized in that the interaction of the returning rods (10) with their corresponding linear slides (8) further promotes the linear displacement of said linear slides (8) and, consequently, the radial backward movements of punch elements (9).

4. The process of claim 1 , characterized in that, during the sub-step (A13), the extending wedges (7) are inclined to return to their initial position.

5. The process of clam 1 , characterized in that, during the sub-steps (A11 ) and (A13), the extending wedges (7) and the returning rods (10) realize a joint movement.

6. The process of clam 1 , characterized in that, during the sub-steps (A11) and

(A13), the extending wedges (7) and the returning rods (10) effectuate an independent movement.

7. The process of clam 1 , characterized in that, during the sub-step (A11), the consequent movement of the linear slides (8) further promotes the forced displacement of the returning rods (10); and, during the sub-step (A13), said returning rods (10) are moved through of an independent backward mechanism (F).

8. A system for deforming slots in stator blades of a dynamo-electric machines, characterized in that it comprises, in the same plant, at least one means for stamping the raw material and forming at least one blade (1), and at least one means to deform the side flaps (5) of the teeth (4) that are adjacent to the slots of at least one blade (1).

9. The system of claim 8, characterized in that said plant comprises a stamping central which is composed by at least one cut stamping module and at least one deformation module by physical collision of movable components.

10. The system of claim 9, characterized in that said deformation module by physical collision of movable components is basically composed by:

at least one set of extending wedges (7) radially arranged;

at least one set of returning rods (10) radially arranged; and

at least one set of linear slides (8) cooperated with said set of extending wedges (7) and returning rod (10);

each linear slide (8) further comprising at least one deforming punch element (9) capable of deforming the side flaps (5) of the teeth (4) that are adjacent to the slots of at least one blade (1) through deformation by physical collision.

11. The system of claim 10, characterized in that said set of extending wedges (7) is capable of promoting the linear movement of the set of linear slides (8).

2. The system of claim 0, characterized in that said set of returning rods (10) is capable of promoting the linear movement of the linear slides (8).

13. The system of claim 11 or 12, characterized in that the interactions between the linear slides (8) and their corresponding extending wedges (7) and returning rods (10) are promoted by the wedge configuration of their corresponding contact ends of such components.

14. The system of claim 10, characterized in that said extending wedges (7) and said returning rods (10) are simultaneously actuated by a hammer of a mechanical press.

15. The system of claim 10, characterized in that said returning rods (10) are actuated by a backward mechanism (F).

16. The system of claim 15, characterized in that said backward mechanism (F) comprises a spring-type backward mechanism.

17. The system of claim 15, characterized in that said backward mechanism (F) comprises an electromechanical-type backward mechanism.