Claims:We claim,
1. A method (200) for assembling a rotor assembly (100) in an electric machine, said method (200) comprising:
connecting a first end plate (106) to a first end (104f) of a rotor pack (104);
assembling a shaft (102) with the first end plate (106) and the rotor pack (104);
connecting a second end plate (108) to a second end (104s) of the rotor pack (104);
grinding the rotor assembly (100);
removing the second end plate (108) from the rotor assembly (100); and
inserting a plurality of pre-magnetized permanent magnets (110) into the rotor pack (104).
2. The method (200) as claimed in claim 1 comprising, dispensing encapsulating agent onto the plurality of pre-magnetized permanent magnets (110) with respect to corresponding magnet receiving portions provided in the rotor pack (104) after said inserting a plurality of pre-magnetized permanent magnets (110) into the rotor pack (104).
3. The method (200) as claimed in claim 2 comprising, connecting the second end plate (108) to the second end (104s) of the rotor pack (104) after said dispensing encapsulating agent onto the plurality of pre-magnetized permanent magnets (110) with respect to corresponding magnet receiving portions in the rotor pack (104).
4. The method (200) as claimed in claim 3 comprising, curing the dispensed encapsulating agent at room temperature after said connecting the second end plate (108) to the second end (104s) of the rotor pack (104).
5. The method (200) as claimed in claim 4 comprising, balancing the rotor assembly (100) by at least one of weight removal and weight addition after said curing the dispensed encapsulating agent at room temperature.
6. The method (200) as claimed in claim 1, wherein the electric machine is at least an interior permanent magnet motor.
7. A rotor assembly (100) for an electric machine, said rotor assembly (100) comprising:
a rotor pack (104);
a first end plate (106) adapted to be connected to a first end (104f) of said rotor pack (104);
a shaft (102) adapted to be engaged with said first end plate (106) and said rotor pack (104);
a plurality of pre-magnetized permanent magnets (110) adapted to be provided to said rotor pack (104); and
a second end plate (108) adapted to be connected to a second end (104s) of said rotor pack (104).
8. The rotor assembly (100) as claimed in claim 7, wherein each of said pre-magnetized permanent magnet (110) is adapted to be received by corresponding each magnet receiving portion provided in said rotor pack (104).
9. The rotor assembly (100) as claimed in claim 8, comprising an encapsulating agent adapted to be dispensed onto each of said re-magnetized permanent magnet (110) with respect to corresponding magnet receiving portion in said rotor pack (104).
10. The rotor assembly (100) as claimed in claim 7 is configured to be provided in at least an interior permanent magnet motor.
, Description:TECHNICAL FIELD
[001] The embodiments herein generally relate to electric machines and more particularly, to a rotor assembly and a method for assembling the rotor assembly with pre-magnetized permanent magnets in an electric machine.
BACKGROUND
[002] Interior permanent magnet (hereinafter IPM) motor is a type of motor which uses high energy magnets such as rare earth based magnets. IPM motors provides superior performance in terms of increased efficiency, improved torque output and reduced noise and thus IPM motors are ideal for use in electric vehicles or hybrid electric vehicles. Usually, IPM motors uses post-magnetized permanent magnets in rotor assembly. Using pre-magnetized permanent magnets in rotor assembly of IPM motors results in increased performance of the IPM motor when compared to the post-magnetized permanent magnets. However, assembly of pre-magnetized permanent magnets in rotor assembly of IPM motors is difficult and is one of the challenges posed to the original equipment manufacturers (OEM).
[003] Therefore, there exists a need for a rotor assembly for an electric machine, which obviates the aforementioned drawbacks. Further, there exists a need for a method for assembling a rotor assembly with pre-magnetized permanent magnets in an electric machine, which obviates the aforementioned drawbacks.
OBJECTS
[004] The principal object of an embodiment of this invention is to provide a rotor assembly for an electric machine, which comprises pre-magnetized permanent magnets.
[005] Another object of an embodiment of this invention is to provide a method for assembling a rotor assembly with pre-magnetized permanent magnets in an electric machine.
[006] 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
[007] 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:
[008] Fig. 1 depicts a perspective view of a rotor assembly with pre-magnetized permanent magnets in an electric machine, according to an embodiment as disclosed herein;
[009] Fig. 2 depicts a cross-sectional view of the rotor assembly with pre-magnetized permanent magnets, according to the embodiment as disclosed herein; and
[0010] Fig. 3 depicts a flowchart showing the steps of a method for assembling a rotor assembly with pre-magnetized permanent magnets in an electric machine, according to an embodiment as disclosed herein.
DETAILED DESCRIPTION
[0011] 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.
[0012] The embodiments herein achieve a method for assembling a rotor assembly with pre-magnetized permanent magnets in an electric machine. Further, embodiments herein achieve a rotor assembly for an electric machine, which comprises pre-magnetized permanent magnets. Referring now to the drawings, and more particularly to Figs. 1 through 3, where similar reference characters denote corresponding features consistently throughout the figures, there are shown embodiments.
[0013] Fig. 1 depicts a perspective view of a rotor assembly (100) with pre-magnetized permanent magnets (110) in an electric machine, according to an embodiment as disclosed herein. Fig. 2 depicts a cross-sectional view of the rotor assembly (100) with pre-magnetized permanent magnets (110), according to the embodiment as disclosed herein. The electric machine (not shown) includes a stator assembly (not shown), a rotor assembly (100) and may include other standard components as present in a standard electric machine. In an embodiment, the rotor assembly (100) includes a shaft (102), a rotor pack (104), a first end plate (106), a second end plate (108, as shown in fig. 1), a plurality of pre-magnetized permanent magnets (110) and an encapsulating agent. 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.
[0014] The shaft (102) is used to support the rotor pack (104). The shaft (102) is adapted to be engaged with the first end plate (106) and the rotor pack (104). The first end plate (106) is adapted to be connected to a first end (104f) of the rotor pack (104). The plurality of pre-magnetized permanent magnets (110) is adapted to be provided to the rotor pack (104). For example, each pre-magnetized permanent magnet (110) is adapted to be received by corresponding each magnet receiving portion (not shown) provided in the rotor pack (104). The second end plate (108) is adapted to be connected to a second end (104s) of the rotor pack (104). The encapsulating agent is adapted to be dispensed onto each pre-magnetized permanent magnet (110) with respect to corresponding magnet receiving portion (not shown) in rotor pack (104). For the purpose of this description and ease of understanding, the magnet receiving portions (not shown) provided in the rotor pack (104) are slots or openings. In an embodiment, the encapsulating agent is at least an epoxy based potting compound. It is also within the scope of the invention to use any other type of encapsulating agent. The rotor assembly (100) is configured to be provided in at least an interior permanent magnet motor. It is also within the scope of the invention to provide the rotor assembly (100) in any other type of motors or generators or any other electric machine without otherwise deterring the intended function of the rotor assembly (100) as can be deduced from the description and corresponding drawings.
[0015] Fig. 3 depicts a flowchart showing the steps of a method (200) for assembling a rotor assembly (100) with pre-magnetized permanent magnets (110) in an electric machine, according to an embodiment as disclosed herein. For the purpose of this description and ease of understanding, the method (200) for assembling the rotor assembly (100) with pre-magnetized permanent magnets (110) in the electric machine is explained herein below with reference to an interior permanent magnet motor. It is also within the scope of the invention to practice/implement the entire steps of the method (200) or with omission of at least one step of the method (200) or with any addition of at least one step to the method (200) for assembling the rotor assembly (100) with pre-magnetized permanent magnets (110) in any other type motors or any other type of generators. In an embodiment, the method (200) for assembling a rotor assembly (100) with pre-magnetized permanent magnets (110), comprises, connecting a first end plate (106) to a first end (104f) of a rotor pack (104), (step 202), assembling a shaft (102) with the first end plate (106) and the rotor pack (104) by press fit or interference fit (step 204), connecting a second end plate (108) to a second end (104s) of the rotor pack (104), (step 206), grinding the rotor assembly (100), step (208), removing the second end plate (108) from the rotor assembly (100), step (210), inserting a plurality of pre-magnetized permanent magnets (110) into the rotor pack (104), (step 210), dispensing encapsulating agent onto the plurality of pre-magnetized permanent magnets (110) with respect to corresponding magnet receiving portions in the rotor pack (104), (step 212), connecting the second end plate (108) to the second end (104s) of the rotor pack (104), (step 214), curing the dispensed encapsulating agent at room temperature, (step 216) and balancing the rotor assembly (100) by at least one of weight removal and weight addition (step 218).
[0016] Therefore, a method (200) for assembling a rotor assembly (100) with pre-magnetized permanent magnets (110) in an electric machine is provided. Further, a rotor assembly (100) with pre-magnetized permanent magnets (110) for an electric machine is provided.
[0017] 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.