DESC:FIELD OF THE INVENTION

The present disclosure relates to stators and particularly relates to methods of manufacturing stator teeth and stator rings of stators for electrical motors.

BACKGROUND

Generally, electric motors such as motors are deployed with a stator as a stationary component relative to rotary components in such motors. The stator provides a magnetic field for driving a rotating component, such as a rotor or a rotating armature. Currently, the stator core is manufactured by compacting or compressing a powdered core material into the corresponding geometry by using a powder compaction press. The powder compaction press includes one or more dies and one or more punches, which are formed to correspond to profiles of respective components to be manufactured. However, such dies and punches are required to be manufactured separately by using unconventional manufacturing processes, for example, Electric Discharge Machining (EDM), which is an expensive process. This leads to a substantially high cost of manufacturing for the stator core.

Further, based on different applications, dimensional characteristics of the stator core may vary and accordingly, the volume of the powered core required for manufacturing such stator core needs to be varied. Based on the volume required, a tonnage of the powder compaction press might need to be changed to perform optimal compression or compaction operation on the powered core. For instance, if a higher volume of the powered core is required for manufacturing the stator core, then the tonnage of the powder compaction press needs to be increased. Owing to such constraints, the implementation of the powder compaction press becomes an expensive process as the initial capital cost of purchasing the powder compaction press is substantially high.

Moreover, after the compaction of the powdered core material, the stator core is required to be kept under high temperatures to eliminate porosity, enhance density, improve mechanical properties, and reduce micro shrinkage. This further adds to the manufacturing cost of the stator teeth and the stator ring.

Furthermore, core losses of the electric motor are directly proportional to a rate of change of magnetic flux and the rotation of the electric motor in revolutions per minute (RPM). In the case of low-speed applications, the electric motor has low RPM and thereby, core losses of the electric motor are also less. Thus, the flow of magnetic flux and a rate of change of magnetic flux through the powdered core material create the core losses. Therefore, the usage of the powdered core material is not suitable, for the low-speed applications of the electric motor, such as ceiling fans, to cater the core losses in the electric motor.

In addition, the stator core made from the compaction of the powdered core material is brittle in nature. Therefore, the machining or reworking of such cores also becomes difficult. Such brittleness in turn increases the possibility of a breakage or cracking of the stator core as well, for example, while being carried on manufacturing lines.

Therefore, in view of the above-mentioned problems, it is desirable to provide methods that can eliminate one or more of the above-mentioned problems associated with the existing techniques.

SUMMARY

This summary is provided to introduce a selection of concepts, in a simplified format, that are further described in the detailed description of the invention. This summary is neither intended to identify key or essential inventive concepts of the invention and nor is it intended for determining the scope of the invention.

The present disclosure relates to a method of manufacturing a stator teeth. The method includes cutting a plurality of sheets of the iron core material into a predefined width. In addition, the method includes stacking the plurality of sheets of the iron core material over each other to form a stack. In addition, the method includes cutting the stacked sheets along a pair of planes substantially at an angle from the plurality of stacked sheets through a machining process. The pair of planes defines a predefined geometrical configuration of at least one stator tooth.

In one or more embodiments, the present disclosure relates to a method of manufacturing a stator ring. The method includes cutting a sheet of the iron core material. In addition, the method includes rolling the sheet of the iron core material concentrically to form a spiral having a plurality of layers of sheet. The plurality of layers abuts one another. In addition, the method includes joining the plurality of layers of the sheet disposed over one another to prevent the loosening and opening of the spiral forming the stator ring.

Further, in one or more embodiments, the method of manufacturing the stator rings includes cutting a first sheet of the iron core material into the predefined width. Further, the first sheet of the iron core material may be rolled to form a first loop. Furthermore, a subsequent sheet may be interlocked with an end of the first sheet, via a joining process such as the welding process. Thus, the unrolling of the first sheet and the subsequent sheet may be prevented. Moreover, the subsequent sheet may be rolled over the first sheet in a concentric manner to form a second loop. The process of interlocking and rolling the subsequent sheets may be performed repetitively until a required thickness of the stator ring is achieved.

As explained earlier, the solid sheets of the iron core material may be used to manufacture the stator teeth and the stator rings instead of the powdered core material. Therefore, the stator teeth and the stator rings manufactured by the method of the present disclosure, are less brittle than the existing components made from the powdered material. This eliminates the risk associated with breakage or crack-related issues. Further, the manufacturing technique includes, but is not limited to, the stamping process, the adhesion process, and the welding process. Such manufacturing techniques are less expensive than the processes like Electric Discharge Machining (EDM) used for manufacturing the existing components. Thus, the implementation of such a method reduces the overall manufacturing cost of the stator teeth and the stator rings.

To further clarify the advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof, which are illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:

Figure 1 illustrates a flowchart depicting a method of manufacturing stator teeth, according to an embodiment of the present disclosure;

Figure 2(a) illustrates a schematic view of sheets of an iron core material stacked over one another as per the proposed method, according to an embodiment of the present disclosure;

Figure 2(b) illustrates a side schematic view of a stator tooth, according to an embodiment of the present disclosure;

Figure 2(c) illustrates a top schematic view of the stator tooth, according to an embodiment of the present disclosure;

Figure 3 illustrates a flowchart depicting a method of manufacturing a stator ring, according to an embodiment of the present disclosure;

Figure 4(a) illustrates a side view of the stator ring of the iron core material having a predefined width, according to an embodiment of the present disclosure; and

Figure 4(b) illustrates a top view of the stator ring, according to an embodiment of the present disclosure.

Further, skilled artisans will appreciate that elements in the drawings are illustrated for simplicity and may not have necessarily been drawn to scale. Furthermore, in terms of the construction of the device, a plurality of components of the device may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

DETAILED DESCRIPTION OF FIGURES

For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated system, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skilled in the art to which invention belongs. The system and examples provided herein are illustrative only and not intended to be limiting.

For example, the term “some” as used herein may be understood as “none” or “one” or “more than one” or “all.” Therefore, the terms “none,” “one,” “more than one,” “more than one, but not all” or “all” would fall under the definition of “some.” It should be appreciated by a person skilled in the art that the terminology and structure employed herein is for describing, teaching, and illuminating some embodiments and their specific features and elements and therefore, should not be construed to limit, restrict or reduce the spirit and scope of the present disclosure in any way.

For example, any terms used herein such as, “includes,” “comprises,” “has,” “consists,” and similar grammatical variants do not specify an exact limitation or restriction, and certainly do not exclude the possible addition of a plurality of features or elements, unless otherwise stated. Further, such terms must not be taken to exclude the possible removal of the plurality of the listed features and elements, unless otherwise stated, for example, by using the limiting language including, but not limited to, “must comprise” or “needs to include.”

Whether or not a certain feature or element was limited to being used only once, it may still be referred to as “plurality of features” or “plurality of elements” or “at least one feature” or “at least one element.” Furthermore, the use of the terms “plurality of” or “at least one” feature or element does not preclude there being none of that feature or element, unless otherwise specified by limiting language including, but not limited to, “there needs to be a plurality of…” or “plurality of elements is required.”

Unless otherwise defined, all terms and especially any technical and/or scientific terms, used herein may be taken to have the same meaning as commonly understood by a person ordinarily skilled in the art.

Reference is made herein to some “embodiments.” It should be understood that an embodiment is an example of a possible implementation of any features and/or elements of the present disclosure. Some embodiments have been described for the purpose of explaining the plurality of the potential ways in which the specific features and/or elements of the proposed disclosure fulfil the requirements of uniqueness, utility, and non-obviousness.

Use of the phrases and/or terms including, but not limited to, “a first embodiment,” “a further embodiment,” “an alternate embodiment,” “one embodiment,” “an embodiment,” “multiple embodiments,” “some embodiments,” “other embodiments,” “further embodiment”, “furthermore embodiment”, “additional embodiment” or other variants thereof do not necessarily refer to the same embodiments. Unless otherwise specified, plurality of particular features and/or elements described in connection with plurality of embodiments may be found in one embodiment, or may be found in more than one embodiment, or may be found in all embodiments, or may be found in no embodiments. Although plurality of features and/or elements may be described herein in the context of only a single embodiment, or in the context of more than one embodiment, or in the context of all embodiments, the features and/or elements may instead be provided separately or in any appropriate combination or not at all. Conversely, any features and/or elements described in the context of separate embodiments may alternatively be realized as existing together in the context of a single embodiment.

Any particular and all details set forth herein are used in the context of some embodiments and therefore should not necessarily be taken as limiting factors to the proposed disclosure.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

The present disclosure discloses a method 100 for manufacturing stator teeth 200 and stator rings 400 for a stator of an electrical machine, such as an electric motor. In one embodiment, the stator teeth 200 and the stator rings 400 may be made by using sheets of an iron core material. In another embodiment, the stator teeth 200 and the stator ring 400 may be made by using sheets of a metallic material, without departing from the scope of the present disclosure.

Figure 1 illustrates a flowchart depicting a method 100 of manufacturing the stator teeth 200, according to an embodiment of the present disclosure. The order in which the method steps are described below is not intended to be construed as a limitation, and any number of the described method steps can be combined in any appropriate order to execute the method or an alternative method. Additionally, individual steps may be deleted from the method without departing from the spirit and scope of the subject matter described herein.

At step 102, the method 100 includes cutting sheets of the iron core material into a predefined width ‘W1’. Each sheet of the iron core material has a predefined length ‘LS’. Herein, a number of sheets of the iron core material may vary based on a predefined height ‘H’ of the stator tooth 200 to be manufactured. The cutting of the stacked sheets along a pair of planes 206 substantially at an angle from a stack 202 is performed through a machining process. The pair of planes 206 defines a predefined geometrical configuration of at least one stator teeth 200.

At step 104, the method 100 includes stacking the sheets of the iron core material over one another. In an embodiment, the stacking of the sheets may be referred to as the stamping of the sheets. Figure 2(a) illustrates a schematic view of sheets of the iron core material stacked over one another as per the proposed method, according to an embodiment of the present disclosure. Referring to Figure 2a, the sheets of the iron core material may be arranged/stacked over each other to form the stack 202 having the predefined width ‘W1’, the predefined length ‘LS’, and the predefined height ‘H’.

In the stack 202, each sheet may be interlocked with the adjacent sheet via a fastening process. In one embodiment, the fastening process may include, but is not limited to, an adhesion process in which adhesives may be applied on a surface of each sheet along lines 204 (shown in Figure 2(a)), such that each sheet may be interlocked with the adjacent sheet. The adhesives may include, but are not limited to, glue or any other adhesive process known in the art. In another embodiment, the fastening process may include, but is not limited to, a laser spot welding used to spot weld the sheets stacked over one another, along the lines 204.

At step 106, the method 100 includes cutting the stacked sheets along planes 206 via a machining process to achieve the required geometrical characteristics/configuration of the stator tooth 200. Figure 2(b) illustrates a side view of the stator teeth 200, according to an embodiment of the present disclosure. Figure 2(c) illustrates a top view of the stator tooth 200, according to an embodiment of the present disclosure.

Referring to Figures 2(a), 2(b), and 2(c), the planes 206 define the geometrical characteristics of the stator tooth 200, and the stack 202 may be cut in accordance with the geometrical characteristics of the stator tooth 200. In an embodiment, the geometrical characteristics may include but are not limited to, the width ‘W1’, the height ‘H’, an upper thickness ‘L2’, and a lower thickness ‘L1’, as shown in Figures 2(b) and 2(c).

In one embodiment, the machining process may be one of Electric Discharge Machining (EDM) and Electro Chemical Discharge Machining (ECDM), and a stamping mechanism. In another embodiment, the machining process may be a wire-cutting process in having a wire used to cut the stacked sheets along the planes 206.

In an embodiment, the one or more stator teeth may be formed from a single stack 202. In a non-limiting embodiment as depicted in Figure 2(a), the stack 202 may be cut along the plane 206 to form three stator teeth. Herein, an inverted tooth may be formed between two adjacent teeth while the stack 202 may be cut along the planes 206. The inverted tooth may be used for motor manufacturing. Thus, the stator tooth 200 may be obtained with negligible scrap.

In an embodiment, the method 300 for manufacturing the stator rings 400 is shown in Figure 3. The order in which the method steps are described below is not intended to be construed as a limitation, and any number of the described method steps can be combined in any appropriate order to execute the method or an alternative method. Additionally, individual steps may be deleted from the method without departing from the spirit and scope of the subject matter described herein.

At step 302, the method 300 includes cutting a sheet of the iron core material. Herein, the sheet of the iron core material may be cut into the predefined width ‘W2’, as shown in Figure 4(a), which illustrates a side view of the first sheet of the iron core material.

At step 304, the method 300 includes rolling the sheet of the iron core material in a concentric manner to form the stator ring 400. Herein, the sheet of the iron core material may be rolled until a required thickness of the stator ring 400 is achieved. In an embodiment, the required thickness of the stator ring 400 may depend on the length of the sheet of the iron core material rolled in the concentric manner to form the stator ring 400.

In an embodiment, the sheet of the iron core material may be rolled to form a spiral roll, as shown in Figure 4(b). Further, an innermost loop of the rolled sheet defines an inner diameter ‘A’ of the stator ring 400 to be manufactured, and an outermost loop of the rolled sheet defines an outer diameter ‘B’ of the stator ring 400 to be manufactured. A difference between the outer diameter ‘B’ and the inner diameter ‘A’ defines the thickness of the stator ring 400.

Further, at step 306, method 300 includes joining the sheet of the iron core material rolled in the concentric manner to form the stator ring 400. The spiral roll of the sheet may be joined via a joining process, such that the unrolling of the spiral roll may be prevented. In a non-limiting embodiment, the joining process may include, but is not limited to, a welding process such as the laser spot welding.

Upon manufacturing the stator rings 400 and the stator teeth 200, both the aforesaid components may be assembled together to form a stator core for the stator.

In the present disclosure, the manufacturing technique includes, but is not limited to, the stamping process, the adhesion process, and the laser spot welding process which are less expensive compared to the processes like Electric Discharge Machining (EDM).

Further, the implementation of methods 100, 300 of the present disclosure eliminates the usage of the existing powder compaction press, the dies, and the punches. The methods 100, 300 also eliminates the manufacturing step associated with the making of the dies, and the punches the required geometrical characteristics of the stator teeth 200 and the stator rings 400. Thus, the cost associated with the purchasing and/or making of the existing powder compaction press, the dies, and the punches, may be eliminated. Therefore, the overall cost associated with the manufacturing of the stator may also be reduced.

Moreover, in the present disclosure, the solid sheets of the iron core material may be used to manufacture the stator teeth 200 and the stator rings 400 instead of the powdered core material. Therefore, the stator teeth 200 and the stator ring 400 manufactured by the method 100, 300 of the present disclosure, are less brittle than the components made from the powdered material, such that breakage or cracking-related issues may be eliminated.

The stator teeth 200 and the stator rings 400 are not required to be kept under high temperatures to improve mechanical properties. Thus, the effort and cost associated with this process may also be eliminated. Furthermore, the solid core material is less expensive than the powered core material, such that the manufacturing cost of the stator teeth 200 and the stator ring 400 may be further reduced. In addition, the solid sheets of the iron core material may also be suitable for low-speed application of the motor such as in ceiling fans.

While specific language has been used to describe the present subject matter, any limitations arising on account thereto, are not intended. As would be apparent to a person in the art, various working modifications may be made to the method in order to implement the inventive concept as taught herein. The drawings and the foregoing description give examples of embodiments. Those skilled in the art will appreciate that one or more of the described elements may well be combined into a single functional element. Alternatively, certain elements may be split into multiple functional elements. Elements from one embodiment may be added to another embodiment.
,CLAIMS:1. A method (100) of manufacturing a stator tooth (200), the method (100) comprising:
cutting a plurality of sheets of the iron core material into a predefined width;
stacking the plurality of sheets of the iron core material over each other to form a stack (202); and
cutting the stacked sheets along a pair of planes (206) substantially at an angle from the stack (202) through a machining process, wherein the pair of planes (206) defines a predefined geometrical configuration of at least one stator teeth (200).

2. The method (100) as claimed in claim 1, wherein the stacking of sheets is performed by stamping the sheets over each other to form the stack (202).

3. The method (100) as claimed in claim 2, wherein a thickness of a stator teeth (200) is proportional to the number of sheets stacked over one other.

4. The method (100) as claimed in claim 1, wherein the stacking of the plurality of sheets is interlocked with one other through at least one of a fastener, an adhesive, and a welding process.

5. The method (100) as claimed in claim 1, wherein the pair of planes (206) define the geometrical configuration of the at least one stator teeth (200).

6. The method (100) as claimed in claim 1, wherein the machining process is at least one of an Electric Discharge Machining (EDM), Electro Chemical Discharge Machining (ECDM), a wire-cutting process, and a stamping mechanism.

7. The method (100) as claimed in claim 1, wherein the plurality of sheets is made of iron core material.

8. A method (300) of manufacturing a stator ring (400), the method (300) comprising:
cutting a sheet of the iron core material;
rolling the sheet of the iron core material concentrically to form a spiral having a plurality of layers of sheet, wherein the plurality of layers abut one another; and
joining the plurality of layers of the sheet disposed over one another to prevent the loosening and opening of the spiral forming the stator ring (400).

9. The method (300) as claimed in claim 8, wherein a predefined thickness of the stator ring (400) is proportional to a length of the sheet of the iron core material rolled in the concentric over one other defining a plurality of layers forming the stator ring (400).

10. The method (300) as claimed in claim 8, wherein the joining is performed through joining the plurality of layers of the sheet over one another through at least one of a fastener, an adhesive, and a welding process.