Structure for fixing permanent magnets in rotor core

Abstract

This invention relates to a structure for fixing a permanent magnet in a rotor core. The structure includes: a magnet receiving portion into which the permanent magnet will be inserted; an internal hole formed in a region adjacent to one end of the magnet receiving portion; and a pressing portion disposed between the magnet receiving portion and the internal hole. The pressing portion is convex in shape toward the permanent magnet to contact it.

Description

Technical Field

[0001] This invention relates to a structure and method for fixing permanent magnets in a rotor core. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not constitute prior art.

[0003] With the trend towards higher power and efficiency in drive motors for environmentally friendly vehicles, interior permanent magnet (IPM) motors have become widely used. Typically, the rotor comprises rare-earth magnets housed within a rotor core. The rotor core has magnet receiving holes to accommodate the individual permanent magnets. To facilitate insertion of the permanent magnets into these holes, the edges of the magnets require a chamfering process. Due to the characteristics of the stamping process, the magnet receiving portion within the rotor core has rounded edges rather than right-angled edges. Therefore, without this chamfering process, it is difficult to insert the permanent magnets into the receiving portion. Even if insertion is achieved, the permanent magnets may be damaged. Furthermore, when the permanent magnets are housed within the magnet receiving portion of the rotor core, an air gap remains between the surface of the receiving portion and the surface of the permanent magnet. Therefore, to reliably secure the permanent magnets within the receiving portion of the rotor core, this air gap needs to be filled with epoxy resin.

[0004] refer to Figure 1 To facilitate the insertion of the permanent magnet 20 into the magnet receiving portion 30 within the rotor core 10, a chamfering process is performed to round the right-angled edges. Because the edges of the permanent magnet 20 are rounded through this chamfering process, the permanent magnet 20 can be easily inserted into the magnet receiving portion 30. However, after the permanent magnet 20 is inserted into the magnet receiving portion 30, a process is required to fill the remaining space in the magnet receiving portion 30 with epoxy resin, and a retaining claw 50 is also needed to securely fix the permanent magnet 20. However, the inventors have found that the chamfering process increases manufacturing costs and reduces motor efficiency. Furthermore, when the size of the magnet receiving portion 30 is increased to facilitate the insertion of the permanent magnet 20 and this undesirable chamfering process is eliminated, excessive air gaps are formed between the surface of the magnet receiving portion and the permanent magnet 20 when the permanent magnet is housed within it, thereby reducing the performance of the drive motor. Summary of the Invention

[0005] This invention provides a structure for fixing a permanent magnet using a pressing portion. This structure eliminates the need for fixing claws to secure the permanent magnet, and also eliminates the need for epoxy resin to fill the air gap between the surface of the permanent magnet and the surface of the magnet receiving portion.

[0006] Another object of the present invention is to provide a method for fixing permanent magnets in a rotor core. This method eliminates the need for the chamfering process of rounding the edges of the permanent magnets.

[0007] According to one aspect of the invention, a structure for fixing a permanent magnet in a rotor core is provided. The structure includes: a magnet receiving portion into which the permanent magnet is to be inserted; an internal hole defined in a region adjacent to one end of the magnet receiving portion; and a pressing portion disposed between the magnet receiving portion and the internal hole. Specifically, the pressing portion is convex in shape toward the permanent magnet and contacts the permanent magnet.

[0008] In the structure, one end of the permanent magnet that comes into contact with the pressing portion may have a right-angled edge.

[0009] In the structure, the pressing portion may include a contact portion and a non-contact portion. The contact portion makes contact with one end of the permanent magnet; the non-contact portion does not make contact with the one end of the permanent magnet. The non-contact portion may be a region closer to the edge of the permanent magnet than the contact portion.

[0010] In the structure, the rotor core may include a pair of permanent magnets inserted into the magnet receiving portion.

[0011] In the structure, one end of each permanent magnet and the other end of each permanent magnet may have right-angled edges, one end of each permanent magnet makes contact with its respective pressing portion, and the other ends of each permanent magnet make contact with each other.

[0012] In the structure described, epoxy resin may not be provided between the permanent magnet and the pressing part.

[0013] In the structure, two magnet receiving parts can be provided in the rotor core, a separator that is part of the rotor core can be arranged between the two magnet receiving parts, and a pair of permanent magnets can be inserted into the two magnet receiving parts respectively.

[0014] In the structure, each of the pairs of permanent magnets may have a rounded edge at one end due to a chamfering process, and the other end may be in contact with the separator. Furthermore, one end of each permanent magnet may have a right-angled edge, and one end of each permanent magnet may be in contact with the pressing portion.

[0015] According to another aspect of the present invention, a method for fixing a permanent magnet in a rotor core is provided. The method includes: forming a magnet receiving portion and an internal hole into which the permanent magnet is to be inserted, the internal hole being defined in a region adjacent to one end of the magnet receiving portion; inserting the permanent magnet into the magnet receiving portion; performing a caulking process by inserting a strip into the internal hole; and using the strip to press a pressing portion disposed between the internal hole and the magnet receiving portion toward the permanent magnet.

[0016] In the method, since the pressing portion is pressed toward the permanent magnet, the chamfering process of rounding the edge of one end of the permanent magnet can be omitted, and the pressing portion makes contact with one end of the permanent magnet.

[0017] In the method described above, since the pressing portion is pressed toward the permanent magnet, the process of applying epoxy resin to the magnet receiving portion into which the permanent magnet is inserted can be omitted.

[0018] In the method, the pressing portion may protrude toward the permanent magnet, and the pressing portion may include a contact area and a non-contact area, the contact area forming contact with one end of the permanent magnet, and the non-contact area not forming contact with the one end of the permanent magnet.

[0019] According to one embodiment of the present invention, the chamfering process of rounding the edges of a pair of permanent magnets can be omitted by means of a pressing portion, wherein the pressing portion fixes the permanent magnets without contacting the edge of one end of each permanent magnet. Therefore, the cost of performing the chamfering process can be reduced.

[0020] According to another embodiment of the invention, it is not necessary to provide retaining claws for fixing the pair of permanent magnets, nor is it necessary to form a large magnet housing to prevent damage to the pair of permanent magnets. Therefore, magnetic flux leakage due to empty space within the retaining claws and rotor core can be prevented. Furthermore, the chamfering process for rounding the edges of the permanent magnets is not performed. Therefore, the magnetic flux of the pair of permanent magnets increases by approximately 0.1 kg, thereby improving motor performance.

[0021] Other areas of application will become apparent from the description provided herein. It should be understood that this specification and specific examples are for illustrative purposes only and are not intended to limit the scope of the invention. Attached Figure Description

[0022] To provide a good understanding of the invention, various embodiments of the invention will now be described by way of example with reference to the accompanying drawings, in which:

[0023] Figure 1 This is a schematic diagram showing the general form of a rotor core in the prior art;

[0024] Figure 2 This is a schematic diagram showing a rotor core structure for fixing a permanent magnet according to an embodiment of the present invention;

[0025] Figure 3 It shows Figure 2 A magnified view of region A in the image;

[0026] Figures 4 to 6 Each of these is a schematic diagram illustrating a method for using a permanent magnet in a fixed rotor core according to an embodiment of the present invention;

[0027] Figure 7 This is a schematic diagram of a rotor core employing a structure for fixing permanent magnets in a rotor core according to another embodiment of the present invention.

[0028] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way. Detailed Implementation

[0029] The following description is merely exemplary in nature and is not intended to limit the invention, application, or use. It should be understood that in all the drawings, corresponding reference numerals denote the same or corresponding parts and features.

[0030] The advantages and features of the invention, as well as the methods for achieving said advantages and features, will become apparent from the accompanying drawings and from the embodiments described in detail below. However, the invention is not limited to the embodiments disclosed below, and various different embodiments thereof can be implemented. These embodiments are provided to provide sufficient information to those skilled in the art regarding the scope of the invention.

[0031] The terms “unit”, “module”, etc., used throughout the specification refer to a single component that performs at least one function or operation and can be implemented in hardware, software, or a combination of both.

[0032] Furthermore, in order to distinguish between constituent elements with the same name, the terms first, second, etc., are used throughout this specification. In the following description, there is no requirement to impose a restriction on the order of the terms.

[0033] The invention is described in detail in an illustrative manner. Furthermore, the foregoing is provided for exemplary embodiments of the invention and is applicable to various combinations and modifications of embodiments in various environments. Modifications or alterations may be made to the invention within the scope of the concepts disclosed herein, the equivalents of the content described herein, and / or the scope of technology or knowledge in the art. Various modifications may also be made to embodiments necessary in the fields where the invention is applicable and where it is desired to be used. Therefore, the disclosed embodiments in the specific description of the invention are not intended to impose any limitation on the invention. Additionally, the appended claims should be construed as also covering other embodiments.

[0034] Figure 2 This is a schematic diagram illustrating a rotor core structure for fixing a permanent magnet according to an embodiment of the present invention.

[0035] refer to Figure 2 The rotor core 100 defines magnet receiving portions 110a and 110b and internal holes 130a and 130b. Permanent magnets 200a and 200b are inserted into the magnet receiving portions 110a and 110b, respectively. Each of the internal holes 130a and 130b is adjacent to one end of a corresponding one of the magnet receiving portions 200a and 200b.

[0036] A pair of permanent magnets 200a and 200b are disposed in the rotor core 100. Therefore, the number of magnet receiving portions 110a and 110b and the number of internal holes 130a and 130b are equal to the number of permanent magnets 200a and 200b. Specifically, the first magnet receiving portion 110a and the second magnet receiving portion 110b are defined in the rotor core 100. The first permanent magnet 200a is inserted into the first magnet receiving portion 110a, and the second permanent magnet 200b is inserted into the second magnet receiving portion 110b. The first internal hole 130a is defined in a region adjacent to one end of the first magnet receiving portion 110a. The second internal hole 130b is defined in a region adjacent to one end of the second magnet receiving portion 110b.

[0037] A pressing portion 150a (i.e., a part of the rotor core 100) is defined between the magnet receiving portion 110a and the internal hole 130a. A pressing portion 150b (i.e., a part of the rotor core 100) is defined between the magnet receiving portion 110b and the internal hole 130b. The pressing portions 150a and 150b are provided in equal numbers to the permanent magnets 200a and 200b. That is, the pressing portions 150a and 150b are used to separate the magnet receiving portion 110a and the internal hole 130a, and the magnet receiving portion 110b and the internal hole 130b, respectively. A separator 170 (i.e., a part of the rotor core 100) is defined between a pair of permanent magnets 200a and 200b.

[0038] Pressing portions 150a and 150b have their respective shapes protruding toward a pair of permanent magnets 200a and 200b. Pressing portions 150a and 150b apply pressure to the pair of permanent magnets 200a and 200b, respectively, thereby fixing the permanent magnets 200a and 200b. Each portion of pressing portions 150a and 150b forms contact with the pair of permanent magnets 200a and 200b, respectively. Pressing portions 150a and 150b each include a first pressing portion 150a and a second pressing portion 150b. The first pressing portion 150a forms contact with one end 201a of the first permanent magnet 200a. The second pressing portion 150b forms contact with one end 201b of the second permanent magnet 200b. The first pressing portion 150a forms contact with one end 201a of the first permanent magnet 200a, but not with the edge adjacent to one end 201a of the first permanent magnet 200a. The first pressing portion 150a fixes the first permanent magnet 200a without contacting the edge of one end 201a of the first permanent magnet 200a. This eliminates the need to perform a chamfering process to round the edge of one end 201a of the first permanent magnet 200a. In other words, the end 201a of the first permanent magnet 200a that contacts the first pressing portion 150a can have a right-angled edge. The second pressing portion 150b contacts one end 201b of the second permanent magnet 200b, but does not contact the edge of one end 201b of the second permanent magnet 200b. The second pressing portion 150b fixes the second permanent magnet 200b without contacting the edge of one end 201b of the second permanent magnet 200b. This eliminates the need to perform a chamfering process to round the edge of one end 201b of the second permanent magnet 200b. In other words, one end 201b of the second permanent magnet 200b that comes into contact with the second pressing portion 150b may have a right-angled edge.

[0039] A pair of permanent magnets 200a and 200b come into contact with the separator 170. In this case, the magnet receiving portions 110a and 110b have rounded edges instead of right-angled edges. Thus, the edges adjacent to the other ends 203a and 203b of the first permanent magnet 200a and the second permanent magnet 200b, respectively, adjacent to the separator 170, are rounded by a chamfering process. Therefore, the other ends 203a and 203b of the first permanent magnet 200a and the second permanent magnet 200b, respectively, adjacent to the separator 170, have rounded edges instead of right-angled edges. Without the chamfering process, when a pair of permanent magnets 200a and 200b are inserted into the magnet receiving portions 110a and 110b, respectively, the edges adjacent to the other ends 203a and 203b of the pair of permanent magnets 200a and 200b, respectively, do not match the corresponding rounded edges of the magnet receiving portions 110a and 110b. Therefore, the permanent magnets 200a and 200b were damaged.

[0040] According to one embodiment of the invention, pressing portions 150a and 150b respectively fix a pair of permanent magnets 200a and 200b. This eliminates the need for the rotor core 100 to include individual retaining claws for fixing the pair of permanent magnets 200a and 200b. Furthermore, the pair of permanent magnets 200a and 200b are fixed within the rotor core 100 without needing to fill empty spaces with epoxy resin. These empty spaces are created after the pair of permanent magnets 200a and 200b are respectively inserted into magnet receiving portions 110a and 110b. Additionally, pressing portions 150a and 150b have their respective shapes protruding toward the pair of permanent magnets 200a and 200b. This reduces the empty spaces between the first permanent magnet 200a and the first magnet receiving portion 110a, and between the second permanent magnet 200b and the second magnet receiving portion 110b.

[0041] According to one embodiment of the invention, the pressing portion 150a fixes the permanent magnet 200a without contacting the edge of one end 201a of the permanent magnet 200a. Furthermore, the pressing portion 150b fixes the permanent magnet 200b without contacting the edge of one end 201b of the permanent magnet 200b. This eliminates the need to perform a chamfering process on the edges of the permanent magnets 200a and 200b. Therefore, the cost of performing the chamfering process can be reduced. However, the chamfering process can be performed on the edges of the permanent magnets 200a and 200b adjacent to the separator 170.

[0042] According to another embodiment of the invention, the rotor core 100 does not include individual retaining claws for securing a pair of permanent magnets 200a and 200b. Furthermore, the rotor core 100 does not need to have individual large magnet receiving portions 110a and 110b to prevent damage to the pair of permanent magnets 200a and 200b. Therefore, magnetic flux leakage due to the retaining claws and the empty space within the rotor core 100 can be prevented. Additionally, the chamfering process of rounding the edges of the pair of permanent magnets 200a and 200b is not performed. Therefore, the magnetic flux of the pair of permanent magnets 200a and 200b is increased by approximately 0.1 kg, thereby improving motor performance.

[0043] Figure 3 It shows Figure 2 A magnified view of region A in the image. For simplicity, the image is compared to the reference image. Figure 2 Content that is identical in description should not be described repeatedly.

[0044] refer to Figure 2 and Figure 3 The first pressing portion 150a includes a contact area 151a that contacts the first permanent magnet 200a and a non-contact area 152a that does not contact the first permanent magnet 200a. The first permanent magnet 200a has a hexahedral shape. Therefore, the first permanent magnet 200a has four edges. The two non-contact areas 152a do not contact the first permanent magnet 200a. That is, the first pressing portion 150a includes the contact area 151a and the non-contact area 152a. The contact area 151a contacts the middle portion of one end 201a of the first permanent magnet 200a. The non-contact areas 152a extend from both ends of the middle portion of one end 201a of the first permanent magnet 200a in opposite directions and do not contact one end 201a of the first permanent magnet 200a. The non-contact area 152a refers to the area closer to the edge of the first permanent magnet 200a than the contact area 151a.

[0045] The first pressing portion 150a has a shape in which the inner surface of the first internal hole 130a is recessed toward the first permanent magnet 200a. Therefore, only a portion of the first pressing portion 150a contacts the first permanent magnet 200a. However, the first pressing portion 150a also has a shape that protrudes due to external force. Therefore, the first permanent magnet 200a is fixed within the rotor core 100 using only the first pressing portion 150a.

[0046] Furthermore, the shape of the first pressing portion 150a prevents it from contacting the edge of one end 201a adjacent to the first permanent magnet 200a. This eliminates the need to perform a separate process to round the edge of one end 201a of the first permanent magnet 200a. Typically, the edge of one end 201a of the first permanent magnet 200a does not match the corresponding edge of the magnet receiving portion 110a. Therefore, the first permanent magnet 200a is damaged. However, according to an embodiment of the invention, the non-contact area 152a of the first pressing portion 150a eliminates the need to round the edge of one end 201a of the first permanent magnet 200a, thereby preventing damage to the first permanent magnet 200a.

[0047] There is a gap between the non-contact area 152a and one end 201a of the first permanent magnet 200a. However, it is not necessary to fill the gap with epoxy resin. This is because the first permanent magnet 200a is fixed within the rotor core 100 using only the first pressing portion 150a.

[0048] Figures 4 to 6 These are schematic diagrams illustrating methods for using permanent magnets in a fixed rotor core according to some embodiments of the present invention.

[0049] refer to Figure 4 The magnet receiving portions 110a and 110b, as well as the internal holes 130a and 130b, are formed by performing a stamping process on the rotor core 100. The formation of the magnet receiving portions 110a and the internal holes 130a creates a pressing portion 150a between them. Similarly, the formation of the magnet receiving portions 110b and the internal holes 130b creates a pressing portion 150b between them. In this case, the pressing portions 150a and 150b have a flat plate shape.

[0050] refer to Figure 5 Pairs of permanent magnets 200a and 200b are inserted into magnet receiving portions 110a and 110b, respectively.

[0051] Subsequently, strips 300a and 300b for performing the caulking process are inserted into the internal holes 130a and 130b, respectively. In this case, strips 300a and 300b may have their respective semi-elliptical cross sections. Strips 300a and 300b may have their respective shapes protruding toward the pressing portions 150a and 150b.

[0052] refer to Figure 6A caulking process is performed to press strips 300a and 300b toward a pair of permanent magnets 200a and 200b, respectively. Through this caulking process, the pressing portions 150a and 150b are changed in shape. Specifically, the pressing portions 150a and 150b, which are pressed toward the pair of permanent magnets 200a and 200b, are changed to protrude toward the pair of permanent magnets 200a and 200b, respectively. Therefore, each portion of the pressing portions 150a and 150b contacts an end 201a and 201b, thereby fixing the permanent magnets 200a and 200b within the rotor core 100, respectively.

[0053] According to one embodiment of the present invention, a pair of permanent magnets 200a and 200b are fixed without the edges of one end 201a of the first permanent magnet 200a and one end 201b of the second permanent magnet 200b respectively forming contact with the pressing portions 150a and 150b. Therefore, the process of forming the fixing claws or the epoxy resin molding process can be omitted.

[0054] Figure 7 This is a schematic diagram of a rotor core employing a structure for fixing permanent magnets in a rotor core according to another embodiment of the present invention. For simplicity, reference numerals are used instead of the reference numerals. Figure 2 Content that is identical in description should not be described repeatedly.

[0055] refer to Figure 7 A magnet receiving portion 110 is formed in the rotor core 100, into which a pair of permanent magnets 200a and 200b are inserted. The pair of permanent magnets 200a and 200b are inserted into the magnet receiving portion 110 such that their respective other ends 203a and 203b are in contact with each other.

[0056] At this time, the edges of the other ends 203a and 203b adjacent to the pair of permanent magnets 200a and 200b do not form contact with the edge of the magnet receiving portion 110. Therefore, the chamfering process of rounding the edges adjacent to the other ends 203a and 203b of the permanent magnets 200a and 200b can be omitted.

[0057] In addition, such as Figure 2 The structure described herein, in which pressing portions 150a and 150b respectively fix permanent magnets 200a and 200b, also eliminates the need to perform a chamfering process on the edges adjacent to one end 201a and 201b of each of the permanent magnets 200a and 200b.

[0058] According to one embodiment of the invention, the pressing portions 150a and 150b allow each end 201a and 201b of a pair of permanent magnets 200a and 200b to have right-angled edges. Furthermore, since the other ends 203a and 203b of the permanent magnets 200a and 200b are inserted into the magnet receiving portion 110 in contact with each other, the other ends 203a and 203b of the permanent magnets 200a and 200b also have right-angled edges. That is, the surfaces of the pair of permanent magnets 200a and 200b can have four right-angled edges. Therefore, the chamfering process for inserting the pair of permanent magnets 200a and 200b into the magnet receiving portion 110 and fixing them without damage is not performed. This simplifies the manufacturing process and thus reduces manufacturing costs.

[0059] The embodiments of the present invention have been described above with reference to the accompanying drawings. It will be apparent to those skilled in the art that other embodiments of the invention can be implemented without any modifications to the technical concept and essential features of the invention. Therefore, it should be understood that the above embodiments are exemplary in each aspect and not restrictive.

Claims

1. A structure for fixing a permanent magnet in a rotor core, the structure comprising: At least one magnet receiving portion, and at least one permanent magnet inserted into the at least one magnet receiving portion; An internal hole is formed in a region adjacent to one end of at least one magnet receiving portion; as well as A pressing portion is disposed between at least one magnet receiving portion and an internal hole, the pressing portion being configured to form a protruding shape toward and contact at least one permanent magnet. The internal hole is formed to penetrate the rotor core.

2. The structure for fixing permanent magnets in a rotor core according to claim 1, wherein, At least one end of the permanent magnet that comes into contact with the pressing portion has a right-angled edge.

3. The structure for fixing permanent magnets in a rotor core according to claim 1, wherein, The pressing portion includes a contact portion and a non-contact portion. The contact portion forms contact with one end of at least one permanent magnet, and the non-contact portion does not form contact with the one end of the at least one permanent magnet. The non-contact portion is the region that is closer to the edge of at least one permanent magnet than the contact portion.

4. The structure for fixing permanent magnets in a rotor core according to claim 1, wherein, The at least one permanent magnet includes a pair of permanent magnets inserted into at least one magnet receiving portion.

5. The structure for fixing permanent magnets in a rotor core according to claim 4, wherein, The first end and the second end of the pair of permanent magnets have right-angled edges; one end of the pair of permanent magnets makes contact with the pressing portion, and the other end of the pair of permanent magnets makes contact with each other.

6. The structure for fixing permanent magnets in a rotor core according to claim 1, wherein, Epoxy resin is not placed between one end of at least one permanent magnet and the pressing portion.

7. The structure for fixing permanent magnets in a rotor core according to claim 1, wherein, The at least one magnet receiving portion includes two magnet receiving portions disposed in the rotor core; A separator formed in a portion of the rotor core is arranged between the two magnet housing portions; The at least one permanent magnet includes a pair of permanent magnets, and the pair of permanent magnets are respectively inserted into the two magnet receiving portions.

8. The structure for fixing permanent magnets in a rotor core according to claim 7, wherein, The first end of each of the pair of permanent magnets has a rounded edge and is configured to make contact with the separator; Each permanent magnet has a right-angled edge at its second end and is configured to make contact with the pressing portion.

9. A method for applying a structure for fixing a permanent magnet in a rotor core according to claim 1, the method comprising: Forming a magnet receiving portion into which a permanent magnet will be inserted and an internal hole defined in a region adjacent to one end of the magnet receiving portion; Insert the permanent magnet into the magnet receiving part; The caulking process is performed by inserting strips into the internal holes; Using a strip, press the pressing part toward the permanent magnet, wherein the pressing part is disposed between the internal hole and the magnet receiving part.

10. The method according to claim 9, wherein, One end of the permanent magnet makes contact with the pressing portion and presses the pressing portion toward the permanent magnet, thereby omitting the chamfering process of rounding the two edges of one end of the permanent magnet.

11. The method according to claim 9, wherein, After inserting the permanent magnet, press the pressing part toward the permanent magnet, thereby eliminating the need for the process of placing epoxy resin in the magnet receiving part.

12. The method according to claim 9, wherein, The pressing part is convex in shape toward the permanent magnet; The pressing part includes a contact area and a non-contact area. The contact area makes contact with one end of the permanent magnet, and the non-contact area does not make contact with the one end of the permanent magnet.

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