Claims:We claim,
1. A rotor lamination (100)for a rotor assembly (10)in an electric machine(100), said rotor lamination (100)comprising:
a plurality of magnet receiving portions(102), whereineach magnet receiving portion(102)defines at least one polarity guide (102PN and 102PS); and
a plurality of slots (104) adapted to facilitate uniform stress distribution across said rotor lamination (100).

2. The rotor lamination (100) as claimed in claim 1, wherein each of said slots (104) is adapted to increase reluctance torque by optimizing flux distribution across said rotor lamination(100).

3. The rotor lamination 100 as claimed in claim 1, wherein the polarity guide (102PN and 102PS) of each of said magnet receiving portion 102 is adapted to be engaged with corresponding polarity guide (12PN and 12PS) provided in corresponding permanent magnet(12) to facilitate insertion of the permanent magnet (12) to corresponding magnet receiving portion (102).

4. The rotor lamination (100) as claimed in claim 3, wherein the polarity guide (102PN and 102PS) of each of said magnet receiving portion (102) is a protrusion and correspondingly the polarity guide (12PN and 102PS) provided in the permanent magnet (12) is a groove.

5. The rotor lamination (100) as claimed in claim 1, wherein the polarity guide (102PN)of each of said magnet receiving portion (102) is at least a north polarity guide adapted to be engaged with corresponding polarity guide (12PN) of the permanent magnet (12)having north polarity.

6. The rotor lamination (100) as claimed in claim 1, wherein the polarity guide(102PS)of each of said magnet receiving portion (102) is at least a south polarity guide adapted to be engaged with corresponding polarity guide (12PS) of the permanent magnet (12) having south polarity.

7. The rotor lamination (100) as claimed in claim 1 includes a plurality of riveting openings (106), wherein each of said riveting opening (106) is adapted to receive corresponding riveting member to facilitate riveting of said lamination (100)with corresponding another rotor lamination during stacking process.

8. The rotor lamination (100) as claimed in claim 1 includes a plurality of interlocking portions (108), wherein each of said interlocking portion (108) is adapted to receive corresponding interlocking member to facilitate interlocking of said rotor lamination (100) with corresponding another rotor lamination during stacking process.

9. The rotor lamination (100) as claimed in claim 1, wherein a central axis C of each of said slot (106) passes in between corresponding two magnet receiving portion (102)which are substantially positioned in a V-shape configuration.

10. The rotor lamination (100) as claimed in claim 1 is configured to be provided in a pre-magnetizedrotor assembly of an interior permanent magnet motor.

11. A rotor assembly (10) for an electric machine, said rotor assembly (10) comprising:
a plurality of permanent magnets (12), wherein each of said permanent magnet (12) includes at least one polarity guide (12PN and 12PS); and
a plurality of rotor laminations (100), wherein each of said rotor lamination (100) includesa plurality of magnet receiving portions (102) adapted to receive corresponding each of said permanent magnet(12),
wherein
eachmagnet receiving portion (102) defines at least one polarity guide (102PN and 102PS) corresponding to the polarity guide (12PN and 12PS) of corresponding each of said permanent magnet (12); and
the polarity guide (102PN and 102PS) of each of said magnet receiving portion (102) is adapted to be engaged with corresponding polarity guide (12PN and 12PS) of corresponding each of said permanent magnet (12) to facilitate insertion of said permanent magnet (12) to corresponding magnet receiving portion (102).

12. The rotor assembly (10) as claimed in claim 11, wherein the polarity guide (102PN and 102PS) of each of said magnet receiving portion (102) is a protrusion and correspondingly the polarity guide (12PN and 102PS) provided in the permanent magnet (12) is a groove.

13. The rotor assembly 10 as claimed in claim 11, wherein the polarity guide (102PN) of each of said magnet receiving portion (102) is at least a north polarity guide adapted to be engaged with corresponding polarity guide (12PN) of said permanent magnet (12) having north polarity.

14. The rotor assembly (10) as claimed in claim 11, wherein the polarity guide (102PS) of each of said magnet receiving portion (102) is at least a south polarity guide adapted to be engaged with corresponding polarity guide (12PS) of the permanent magnet (12) having south polarity.

15. The rotor assembly (10) as claimed in claim 11, wherein each rotor lamination (100) includes,
a plurality of slots (104) adapted to facilitate uniform stress distribution across said rotor lamination (100) and to increase reluctance torque by optimizing flux distribution across said rotor lamination (100);
a plurality of first openings (106), wherein each of said opening (106) is adapted to receive corresponding riveting member to facilitate riveting of said lamination (100) with corresponding another rotor lamination during stacking process; and
a plurality of interlocking portions (108), wherein each of said interlocking portion (108) is adapted to receive corresponding interlocking member to facilitate interlocking of said rotor lamination (100) with corresponding another rotor lamination during stacking process.

16. The rotor assembly (10) as claimed in claim 11 is configured to be provided in an interior permanent magnet motor.
, Description:TECHNICAL FIELD
[001] The embodiments herein generally relate toelectric machines and more particularly, to a rotor lamination and a rotor assembly for an electric machine such as an interior permanent magnet motor.

BACKGROUND
[002] Interior permanent magnet (hereinafter IPM) motor is a type of motor which includes electrical windings in stator and permanent high energy magnets such as rare earth based magnets in rotor.Such windings include a conductor wire formed as solid conductor segments or bars that are shaped to be securely held within a core, bobbin, or other structure. Such conductors may be formed as individual segments/coils that are assembled into a stator and then welded together to form a winding. Further, the rotor is rotatable within the stator and comprises magnets built-in the interior of the rotor. Each magnetic pole on the rotor is conventionally created by putting permanent magnet material into slots formed in the laminated stack of the rotor.
[003] IPM rotary machines can have a plurality of permanent magnets implanted within the rotor. Such rotary electric machines have advantages over other machines, such as increased rotor strength and resistance to the effects of centrifugal force on the rotor. In addition (when the rotary electric machine is operated as a motor), the motive torque that is developed by the rotor is made up of magnetic torque resulting from the flow of magnetic flux of the permanent magnets of the rotor and reluctance torque that results from differences in magnetic resistance between respective circumferential portions of the rotor.
[004] Conventionally, the rotor lamination does not include any provisions to simplify pre-magnetized magnet assembly. Further, the rotor lamination does not provide options for multiple stacking methods. Furthermore, the rotor laminations need to be optimized and modified to provide optimized reluctance torque and unifrom stress distribution across the lamination.
[005] Therefore, there exists a need for a rotor lamination for a rotor assembly in an electric machine which obviates the aforementioned drawbacks. Further, there exists a need for a rotor assembly for an electric machine which obviates the aforementioned drawbacks.

OBJECTS

[006] The principal object of an embodiment herein is toprovide a rotor lamination for a rotor assembly in an electric machine, which provides polarity guides in rotor lamination and permanent magnets to assistin assembly of permanent magnets to the rotor lamination stack.
[007] Another object of an embodiment herein is to provide a rotor lamination for a rotor assembly in an electric machine, which has optimized design to provide high reluctance torque and to provide uniform stress distribution across each rotor lamination
[008] Another object of an embodiment herein is to provide a rotor lamination for a rotor assembly in an electric machine, which provides polarity guides in rotor lamination and permanent magnets to assist in assemblyof permanent magnet to rotor lamination stack, and has an optimized design to provide high reluctance torque and to provide uniform stress distribution across each rotor lamination.
[009] Another object of an embodiment herein is to provide a rotor lamination for a rotor assembly in an electric machine, which provides maximum flux flow along d-axis of the rotor lamination.
[0010] Another object of an embodiment herein is to provide a rotor lamination for a rotor assembly in an electric machine, which provides provision for rivetting and interlocking the rotor lamination without deterioration in the performance of the rotor
[0011] Another object of an embodiment herein is to provide a rotor assembly for an electric machine, which improves performance of the electric machine and assists in assembly of permanent magnets.
[0012] These and other objects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF DRAWINGS
[0013] The embodiments of the invention are illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[0014] Fig. 1 depicts a perspective view of a rotor assembly of an electric machine such as an interior permanent magnet motor, according to the embodiment as disclosed herein;
[0015] Fig. 2depicts a front view of a rotor lamination of the rotor assembly, according to the embodiment as disclosed herein;
[0016] Fig. 3a and 3b depicts an enlarged view of magnet receiving portion having polarity guides in rotor lamination and permanent magnets assembled to the magnet receiving portion thereof, according to the embodiment as disclosed herein; and
[0017] Fig. 4 depicts a perspective view of a rotor stack with permanent magnets assembled thereof, according to the embodiment as disclosed herein.

DETAILED DESCRIPTION
[0018] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0019] The embodiments herein achieve arotor lamination for a rotor assembly in an electric machine, which provides polarity guides to simplify pre-magnetized magnet assembly. Further, embodiments herein achieve a rotor assembly for an electric machine, which improves performance of the electric machine and assists in assembly process. Referring now to the drawings, and more particularly to Figs. 1 through 4, where similar reference characters denote corresponding features consistently throughout the figures, there are shown embodiments.
[0020] Fig. 1 depicts a perspective view of a rotor assembly (10) of an electric machine such as an interior permanent magnet motor, according to the embodiment as disclosed herein.In an embodiment, the electric machine (not shown) includes a stator assembly (not shown), a rotor assembly(10) and may include other standard components as present in a standard electric machine. In an embodiment, the rotor assembly (10) includes a shaft (12S), a plurality of permanent magnets (12), a plurality of rotor laminations (100), a first end plate (12F) and a second end plate (not shown). In an embodiment, each permanent magnet (12) includes polarity guides (12PN and 12PS) to assist in assembly of permanent magnets (12) to the rotor laminations (100). In an embodiment, each rotor lamination (100) includes a plurality of magnet receiving portions (102) with polarity guides (102PN and 102PS), a plurality of slots (104), a plurality of riveting openings (106) and a plurality of interlocking portions (108). For the purpose of this description and ease of understanding, the electric machine is explained herein below with reference to an interior permanent magnet motor used in at least one of an electric vehicle and a hybrid electric vehicle. However, it is also within the scope of the invention to use the electric machine as electric generator or electric motor in any other applications without otherwise deterring the intended function of the electric machine as can be deduced from the description and corresponding drawings.
[0021] Fig. 2 depicts a front view of a rotor lamination (100) of the rotor assembly (10), according to the embodiment as disclosed herein.The plurality of rotor laminations (100) is called as rotor lamination stack. For the purpose of this description and ease of understanding, the plurality of rotor lamnations (100) are configured to be provided in a pre-magnetized rotor assembly (10) of an interior permanent magnet motor. However, it is also within the scope of the embodiment herein to provide the plurality of rotor laminations (100) is any other rotor assembly present in any type of electric machine without otherwise detering the intended function of the rotor lamination (100) as can be deduced from the description and corresponding drawings.Each magnet receiving portion (102) of each rotor lamination (100) is adapted to recevie corresponding permanent magent (12) having corresponding polarity. For the purpose of this description and ease of understanding, each magnet receiving portion (102) of each rotor lamination (100) is at least an opening. It is also within the scope of the embodiment herein to provide each magnet receiving portion (102) of each rotor lamination (100) in form of groove, slot and any other means corresponding to type and configuration of the electric machine. Each magnet receiving portion (102) of each rotor lamination (100) is positioned inward of the outer diameter(D) of the rotor lamination (100). Each magent receiving portion (102) of each rotor lamination (100) is provided at a first distance from the outer diameter(D). In an embodiment, each of twocorresponding magent receiving portions (102) in the plurality of magnet receiving portions (102) are positioned substantially in a V-shape configuration. It is also within the scope of the embodiment herein to provide the plurality of magnet receiving portions (102) in any other pattern and orientaiton and any other configuration. In an embodiment, each magent receiving portion (102) of the rotor lamiantion (100) defines at least one polarity guide (102PN and 102PS). The polarity guide (102PN and 102PS) of each magnet receiving portion (102) of the rotor lamination (100) is adapted to be engaged with corresponding polarity guide (12PN and 12PS) provided in corresponding permanent magnet (12) to facilitate insertion of the permanent magnet (12) to corresponding magnet receiving portion (102) of the rotor lamination. For example, the polarity guide (102PN as shown in fig. 3a) of each magnet receiving portion (102) of the rotor lamination (100) is at least a north polarity guide adapted to be engaged with corresponding polarity guide (12PN) of the permanent magnet (12) having north polarity. The polarity guide (102PN) of each magnet receiving portion (102) of the rotor lamination (100) is defined at a top surface which is nearer to the outer diameter (D) of the rotor lamination (100). Further, the polarity guide (102PS as shown in fig. 3b) of each magnet receiving portion (102) of the rotor lamination (100) is at least a south polarity guide adapted to be engaged with corresponding polarity guide (12PS) of the permanent magnet (12) having south polarity. The polarity guide (102PS) of each magnet receiving portion (102) of the rotor lamination (100) is defined at a bottom surface which is away from the outer diameter (D) of the rotor lamination (100). In one embodiment, the polarity guide (102PN and 102PS) of each magnet receiving portion (102) is a protrusion and correspondingly the polarity guide (12PN and 102PS) provided in the permanent magnet (12) is a groove. In another embodiment, the polarity guide (102PN and 102PS) of each magnet receiving portion (102) is a groove and correspondingly the polarity guide (12PN and 12PS) provided in the permanent magnet (12) is a protrusion.
[0022] In an embodiment, the plurality of slots (104) of each rotor lamination (100)is adapted to facilitate uniform stress distribution across rotor lamination (100) and to increase reluctance torque by optimizing flux distribution across said rotor lamination (100).Each slot (104) of each rotor lamination (100) is positioned at a second distance from the outer diameter (D) and below the magnet receiving portions (102). In an embodiment, a central axis (C) of each slot (104) passes in between corresponding two magnet receiving portion (102) which are substantially positioned in a V-shape configuration.
[0023] Each riveting opening (106) of each rotor lamination (100) is adapted to receive corresponding riveting member (not shown) to facilitate riveting of said lamination (100) with corresponding another rotor lamination (not shown) during stacking process of rotor lamination (100). Each riveting opening (106) of each rotor lamination (100) is positioned nearer to the outer diameter (D) and above the magnet receiving portion (102) and intersects the central axis (C) of corresponding slot (104).
[0024] Each interlocking portion (108) of each rotor lamination (100) is adapted to receive corresponding interlocking member to facilitate interlocking of the rotor lamination (100) with corresponding another rotor lamination (not shown) during stacking process of rotor laminations (100). Each interlocking portion (108) is at least an opening. Each interlocking portion (108) of each rotor lamination (100) is positioned in between two corresponding slot (106).
[0025] The shaft (12S) is used to support the rotor lamination stack (100). The first end plate (12F) and the second end plate (not shown) are engaged with corresponding ends of the rotor lamination stack (100). Each permanent magnet (12) includes at least one polarity guide (12PN and 12PS) adapted to be engaged with corresponding polarity guide (102PN and 102PS) of corresponding each magnet receiving portion (102) of the rotor lamination (100) to facilitate insertion of the permanent magnet (12) to the magnet receiving portion (102). For the purpose of this description and ease of understanding, each permanent magnet (12) is at least a pre-magnetized permanent magnet. It is also within the scope of the invention to provide any other type of permanent magnets in the rotor assembly (10) without otherwise deterring the intended function of the permanent magnet (12) as can be deduced from the description and corresponding drawings. In an embodiment, the plurality of permanent magnets (12 as shown in fig. 4) are inserted into corresponding magnet receiving portion (102) with alternately reversing polarity at each V shaped configuration.
[0026] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.