Iron core of squirrel cage rotor and squirrel cage rotor

Abstract

The invention provides an iron core of a squirrel cage rotor and the squirrel cage rotor. A plurality of guide grooves (10) are formed in the iron core, the guide grooves (10) are used for containing guide bars of the squirrel cage rotor, the guide grooves (10) at least form deformation areas (S) in the areas close to the axial ends of the iron core, and the circumferential width of the deformation areas (S) is alternately decreased and increased at the same position in the axial direction of the iron core and in the radial outward direction, or the circumferential width of the deformation areas (S) is alternately decreased and increased at different positions in the axial direction. And the distance from the radial innermost side area of the deformation area (S) to the central axis of the iron core is firstly reduced and then increased or is firstly increased and then reduced. According to the iron core of the squirrel-cage rotor, the guide grooves with special structures are provided, and the stress at the joints of the guide bars formed by casting the guide grooves and the end rings is very small, so that the squirrel-cage rotor can bear very high rotating speed, and the motor efficiency is not influenced.

Description

Technical Field

[0001] The invention relates to the field of motors, and more particularly to an iron core of a squirrel cage rotor and a squirrel cage rotor. Background Art

[0002] Figure 1 and Figure 2 A squirrel cage rotor is shown, which includes an iron core C', a conductive bar and an end ring R. A conductive bar slot B is formed in the iron core C', and the conductive bar is formed in the conductive bar slot B by casting.

[0003] As the demand for high speed of the drive motor increases, the strength problem of the end ring R of the squirrel cage rotor becomes prominent. In order to ensure the structural strength of the end ring R at high speed, the main method of the existing technology is to improve the strength of the cast aluminum material. However, as the material strength increases, the conductivity of the cast aluminum material tends to decrease, which will lead to a decrease in the efficiency of the drive motor, an increase in loss and a larger temperature rise.

[0004] Therefore, how to improve the connection strength between the end ring R and the guide bar without changing the casting material is an urgent problem to be solved in this field. Summary of the invention

[0005] The object of the present invention is to overcome or at least alleviate the deficiencies of the above-mentioned prior art and to provide an iron core of a squirrel cage rotor and a squirrel cage rotor.

[0006] According to a first aspect of the present invention, there is provided an iron core of a squirrel cage rotor, wherein the iron core is formed with a plurality of guide slots, wherein the guide slots are used to accommodate the guide bars of the squirrel cage rotor. The guide groove forms a deformation zone at least in a region close to an axial end of the core, and the deformation zone is located in a radially innermost region of the guide groove. At the same position in the axial direction of the core, the circumferential width of the deformation zone decreases and increases alternately along the radial outward direction.

[0007] In at least one embodiment, at different positions in the axial direction, the distance from the radially innermost area of ​​the deformation zone to the central axis of the core first decreases and then increases, or first increases and then decreases.

[0008] In at least one embodiment, the deformation zone includes one or more circumferential recesses, so that the circumferential width of the deformation zone gradually decreases and increases in a radially outward direction.

[0009] In at least one embodiment, the deformation zone includes one or more circumferential protrusions, so that the circumferential width of the deformation zone increases and decreases sequentially in the radial outward direction.

[0010] In at least one embodiment, perpendicular to the axial direction of the core, the cross-section of the core at each axial position is the same.

[0011] In at least one embodiment, perpendicular to the axial direction of the core, the cross-sections of the core at different axial locations are not completely the same. The iron core includes at least one conventional stack and two special-shaped stacks, wherein the conventional stack is sandwiched by the two special-shaped stacks in the axial middle, the deformation zone is only located in the special-shaped stack, and the guide groove forms a conventional guide groove hole in the area where the conventional stack is located, and the conventional guide groove hole does not have the recessed portion or the protruding portion.

[0012] In at least one embodiment, the core includes at least three conventional stacks and two special-shaped stacks, and a conventional stack, a special-shaped stack, a conventional stack, a special-shaped stack, and a conventional stack are sequentially stacked from one end to the other end along the axial direction of the core. The guide groove forms a conventional guide groove hole in the area where the conventional stack is located, and forms a shaped guide groove hole in the area where the shaped stack is located. The distance from the radial innermost area of ​​the special-shaped guide slot hole to the center axis of the iron core is smaller than the distance from the radial innermost area of ​​the conventional guide slot hole to the center axis of the iron core, or the distance from the radial innermost area of ​​the special-shaped guide slot hole to the center axis of the iron core is larger than the distance from the radial innermost area of ​​the conventional guide slot hole to the center axis of the iron core.

[0013] In at least one embodiment, the axial dimension of the conventional stack located in the middle in the axial direction accounts for more than 80% of the axial dimension of the core.

[0014] According to a second aspect of the present application, a squirrel cage rotor is provided, comprising an iron core and a conductive bar, wherein the iron core is the iron core according to the first aspect of the present application, and the conductive bar is embedded in the guide slot of the iron core.

[0015] The iron core of the squirrel cage rotor according to the present invention provides a guide groove of a special structure, and the stress at the junction of the guide bar and the end ring formed by casting through the guide groove is very small, so that the squirrel cage rotor according to the present application can withstand a very high rotation speed without affecting the motor efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of a squirrel cage rotor with a rotating shaft in the prior art cut away along the axial direction.

[0017] Figure 2 It is a schematic diagram of the iron core of the squirrel cage rotor in the prior art.

[0018] Figure 3 is a schematic diagram of an iron core of a squirrel cage rotor according to a first embodiment of the present application.

[0019] Figure 4 yes Figure 3 A schematic diagram of a partial enlargement of the corresponding iron core perpendicular to the axial section.

[0020] Figure 5 is a schematic diagram of an iron core of a squirrel cage rotor according to a second embodiment of the present application.

[0021] Figure 6 yes Figure 5 A schematic diagram of a partial enlargement of the corresponding iron core perpendicular to the axial section.

[0022] Figure 7 is a schematic diagram of an iron core of a squirrel cage rotor according to a third embodiment of the present application.

[0023] Figure 8 yes Figure 7 A schematic diagram of the corresponding iron core cut along the axial direction.

[0024] Fig. 9 is a schematic diagram of a cross section perpendicular to the axial direction of a conventional stack of a squirrel cage rotor according to a third embodiment of the present application.

[0025] Fig.10 4 is a schematic diagram of a cross section perpendicular to the axial direction of a profiled stack of a squirrel cage rotor according to a third embodiment of the present application.

[0026] Fig.11 is a schematic diagram of an iron core of a squirrel cage rotor according to a fourth embodiment of the present application.

[0027] Fig.12 yes Fig.11 A schematic diagram of the corresponding iron core cut along the axial direction.

[0028] Fig.13 is a schematic diagram of a cross section perpendicular to the axial direction of a conventional stack of a squirrel cage rotor according to a fourth embodiment of the present application.

[0029] Fig.14 4 is a schematic diagram of a cross section perpendicular to the axial direction of a profiled stack of a squirrel cage rotor according to a fourth embodiment of the present application.

[0030] Fig.15 is a schematic diagram of an iron core of a squirrel cage rotor according to a fifth embodiment of the present application.

[0031] Fig.16 4 is a schematic diagram of a cross section perpendicular to the axial direction of a profiled stack of a squirrel cage rotor according to a fifth embodiment of the present application.

[0032] Fig.17 is a schematic diagram of a cross section perpendicular to the axial direction of a conventional stack of a squirrel cage rotor according to a fifth embodiment of the present application.

[0033] Fig.18 is a schematic diagram of an iron core of a squirrel cage rotor according to a sixth embodiment of the present application.

[0034] Fig.19 4 is a schematic diagram of a cross section perpendicular to the axial direction of a profiled stack of a squirrel cage rotor according to a sixth embodiment of the present application.

[0035] Fig. 20 is a schematic diagram of a cross section perpendicular to the axial direction of a conventional stack of a squirrel cage rotor according to a sixth embodiment of the present application.

[0036] Description of reference numerals: C, C' iron core; B guide bar groove; R end ring; C1 conventional stack; C2 special-shaped stack; 10 guide groove; 11 recess; 12 convex part; 101 conventional guide groove hole; 102 special-shaped guide groove hole; S deformation zone. DETAILED DESCRIPTION

[0037] The exemplary embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that these specific descriptions are only used to teach those skilled in the art how to implement the present invention, and are not intended to exhaust all possible modes of the present invention, nor to limit the scope of the present invention.

[0038] Reference Figures 3 to 20 , introduce the iron core and squirrel cage rotor according to the present application.

[0039] Unless otherwise specified, the radial, axial and circumferential directions mentioned in this application are all referenced to the radial, axial and circumferential directions of the core.

[0040] First embodiment Reference Figure 3 and Figure 4 , introduces the core of the squirrel cage rotor according to the first embodiment of the present application.

[0041] The core C is formed with a plurality of guide grooves 10 for accommodating the guide bars (not shown) formed by casting. The contour shapes of the guide grooves 10 in different axial positions in this embodiment are the same, or in other words, the cross-sections of the core perpendicular to the axial direction are the same in different axial regions.

[0042] The radially innermost region of each guide groove 10 is formed as a deformation zone S. Figure 4 The deformation zone S includes two concave portions 11 that are concave in the circumferential direction, so that the circumferential width of the deformation zone S varies in the radial direction. In this embodiment, along the direction from the radial inside to the radial outside, the circumferential width of the deformation zone decreases, increases, decreases again, and increases again in sequence.

[0043] It can be understood that the number of recesses 11 in the deformation zone S may be other numbers, such as 1 or 3.

[0044] The special structure of the deformation zone S can increase the friction between the guide bar and the core, thereby reducing the stress at the junction of the guide bar and the end ring. When the end ring is subjected to centrifugal force, the guide bar near the inner diameter side and the end side of the core in the guide groove 10 will be subjected to the combined action of radial and axial forces. The radial force on the guide bar can offset the aforementioned friction force, and then the centrifugal force on the end ring can be offset, thereby reducing the stress and deformation of the squirrel cage at high speed. Figure 1 and Figure 2 The squirrel cage rotor of the prior art shown in the figure, under the condition that the casting material of the guide bars and the end rings remains unchanged, the end rings of the squirrel cage rotor according to the present embodiment can resist a greater centrifugal force and adapt to a higher rotation speed.

[0045] Second embodiment Reference Figure 5 and Figure 6 The second embodiment of the present application is introduced. The second embodiment is a modification of the first embodiment, and components having the same or similar structures or functions as those in the first embodiment are marked with the same reference numerals, and detailed descriptions of these components are omitted.

[0046] The difference between this embodiment and the first embodiment mainly lies in the specific concavo-convex structure of the deformation zone S. In this embodiment, the deformation zone S includes two convex portions 12 protruding in the circumferential direction, so that in this embodiment, along the direction from the radial inside to the radial outside, the circumferential width of the deformation zone increases, decreases, increases again, and decreases again in sequence.

[0047] It is understandable that the number of the protrusions 12 in the deformation zone S may be other numbers, such as 1 or 3.

[0048] Third embodiment Reference Figures 7 to 10 The third embodiment of the present application is introduced. The third embodiment is a variation of the first embodiment, and the difference between the third embodiment and the first embodiment is mainly as follows: First, the cross sections of the core perpendicular to the axial direction are not completely the same in different axial regions. The deformation zone S is only located at the two axial ends of the core C, and the structure of the main area of ​​the guide slot 10 in the middle of the core is basically the same as the guide slot structure of the prior art.

[0049] Second, the deformation of the deformation zone S is manifested as a change in the distance from the radially innermost region of the guide slot 10 to the central axis of the core, rather than a change in the circumferential dimension.

[0050] Specifically, according to the different shapes and sizes of the guide slots 10 in different sections, the core C in this embodiment can be divided into five sections in the axial direction, namely, conventional stack C1, special-shaped stack C2, conventional stack C1, special-shaped stack C2 and conventional stack C1.

[0051] The structure of the conventional guide slot hole 101 corresponding to the guide slot 10 in the conventional stack C1 is basically the same as the cross-sectional structure of the guide slot in the prior art. The distance from the radial innermost area of ​​the special-shaped guide slot hole 102 corresponding to the guide slot 10 in the special-shaped stack C2 area to the center axis of the iron core is different from the distance from the radial innermost area of ​​the conventional guide slot hole 101 to the center axis of the iron core.

[0052] In this embodiment, the axial length of the conventional stack C1 located in the middle is the longest, and this part of the conventional stack C1 constitutes the main part of the core C1. For example, the axial length of the conventional stack C1 located in the middle accounts for more than 80% of the axial length of the core C. The axial dimensions of the remaining conventional stacks C1 and the special-shaped stacks C2 are relatively small. For example, the axial lengths of the conventional stacks C1 and the special-shaped stacks C2 located at the ends account for less than 5% of the axial length of the core C.

[0053] It is worth noting that, although the core C is divided into five sections in the introduction, in actual production the core C does not necessarily have to be composed of exactly five separate core stacks. For example, the conventional stack C1 located in the middle can be composed of several semi-finished core stacks of the same shape.

[0054] In this embodiment, the distance from the radial innermost area of ​​the conventional guide slot hole 101 to the central axis of the core is r1, and the distance from the radial innermost area of ​​the special-shaped guide slot hole 102 to the central axis of the core is r2, and r2>r1. Therefore, in the deformation zone S, that is, the section from the axial end area of ​​the conventional stack C1 located in the middle to the special-shaped stack C2 and then to the conventional stack C1 located at the end, the distance from the radial innermost side of the guide slot 10 to the central axis of the core first increases and then decreases.

[0055] The special structure of the deformation zone S in this embodiment can increase the axial force between the conductor bar and the core, thereby reducing the stress at the junction of the conductor bar and the end ring. Figure 1 and Figure 2 The squirrel cage rotor of the prior art shown in the figure, under the condition that the casting material of the guide bars and the end rings remains unchanged, the end rings of the squirrel cage rotor according to the present embodiment can resist a greater centrifugal force and adapt to a higher rotation speed.

[0056] Fourth embodiment Reference Figures 11 to 14The fourth embodiment of the present application is introduced. The fourth embodiment is a variation of the third embodiment, and the difference between this embodiment and the third embodiment is mainly that the distance from the radial innermost area of ​​the guide slot 10 in the section where the deformation zone S is located to the central axis of the iron core first decreases and then increases. Specifically, in this embodiment, the distance from the radial innermost area of ​​the conventional guide slot hole 101 to the central axis of the iron core is r1, and the distance from the radial innermost area of ​​the special-shaped guide slot hole 102 to the central axis of the iron core is r2, and r2<r1.

[0057] The special structure of the deformation zone S in this embodiment can also increase the axial force between the conductor bar and the core, thereby reducing the stress at the junction of the conductor bar and the end ring.

[0058] Fifth embodiment Reference Figures 15 to 17 The fifth embodiment of the present application is introduced. The fifth embodiment is a combination of the first embodiment and the third embodiment.

[0059] The main difference between this embodiment and the first embodiment is that the cross-sections of the core perpendicular to the axial direction are not completely the same in different axial regions. The deformation zone S is only located at the two axial ends of the core C, and the shape of the main area of ​​the guide slot 10 in the middle of the core is basically the same as the structure of the prior art.

[0060] The difference between this embodiment and the third embodiment is that the deformation of the deformation zone S is manifested as a change in the circumferential dimension of the guide groove 10, which is similar to the first embodiment. In the deformation zone S, the circumferential width of the deformation zone S alternately decreases and increases in the radially outward direction.

[0061] Specifically, the core C in this embodiment can be divided into three sections in the axial direction, namely, the special-shaped stack C2, the conventional stack C1 and the special-shaped stack C2.

[0062] The structure of the conventional guide slot hole 101 corresponding to the conventional stack C1 region of the guide slot 10 is substantially the same as the cross-sectional structure of the guide slot in the prior art. The deformation zone S is located at the radial innermost region of the shaped guide slot hole 102 corresponding to the shaped stack C2 region of the guide slot 10.

[0063] Reference Fig.16 The deformation zone S includes two concave portions 11 that are concave in the circumferential direction, so that the circumferential width of the deformation zone S varies in the radial direction. In this embodiment, along the direction from the radial inside to the radial outside, the circumferential width of the deformation zone decreases, increases, decreases again, and increases again in sequence.

[0064] In this embodiment, the axial length of the conventional stack C1 located in the middle is the longest, and this part of the conventional stack C1 constitutes the main part of the core C1. For example, the axial length of the conventional stack C1 located in the middle accounts for more than 80% of the axial length of the core C. The axial length of the special-shaped stack C2 is relatively small. For example, the axial length of each special-shaped stack C2 located at the end accounts for less than 10% of the axial length of the core C.

[0065] Similar to the first embodiment, the special structure of the deformation zone S in this embodiment can increase the radial force between the conductor bar and the core, thereby reducing the stress at the junction of the conductor bar and the end ring.

[0066] Sixth Embodiment Reference Figures 18 to 20 The sixth embodiment of the present application is introduced. The sixth embodiment is a variation of the fifth embodiment. The difference between the sixth embodiment and the fifth embodiment is that the deformation zone S includes two convex portions 12 protruding in the circumferential direction, so that the circumferential width of the deformation zone S varies in the radial direction. In the present embodiment, along the direction from the radial inner side to the radial outer side, the circumferential width of the deformation zone increases, decreases, increases again, and decreases again in sequence.

[0067] Similar to the fifth embodiment, the special structure of the deformation zone S in this embodiment can increase the radial force between the conductor bar and the core, thereby reducing the stress at the junction of the conductor bar and the end ring.

[0068] It should be understood that the above embodiments and some aspects or features thereof can be appropriately combined. For example, the third and fourth embodiments can be further combined with the first or second embodiments, that is, the deformation zone S is not only deformed as a change in the distance from the radial innermost area of ​​the guide slot 10 to the central axis of the core, but also as a change in the circumferential dimension.

[0069] The present invention further provides a squirrel cage rotor, which comprises a guide bar and an iron core C provided according to any one of the aforementioned embodiments, wherein the guide bar is embedded in a guide slot 10 of the iron core C by casting.

[0070] The present invention has at least one of the following advantages: (i) The guide slots of the iron core of the squirrel cage rotor according to the present invention have deformation zones. The stress at the junction of the guide bars and the end rings formed by casting the guide slots of this structure is very small, so that the squirrel cage rotor according to the present application can withstand very high rotation speeds without affecting the motor efficiency.

[0071] (ii) The present invention provides a variety of variations of the guide groove deformation zone, which can be selected according to the requirements of specific process parameters in production applications.

[0072] Of course, the present invention is not limited to the above-mentioned embodiments, and those skilled in the art may make various modifications to the above-mentioned embodiments of the present invention under the guidance of the present invention without departing from the scope of the present invention.

Claims

1. An iron core of a squirrel cage rotor, the iron core being formed with a plurality of guide slots (10), the guide slots (10) being used to accommodate guide bars of the squirrel cage rotor, characterized in that: The guide groove (10) forms a deformation zone (S) in a region at least close to an axial end of the iron core, and the deformation zone (S) is located in a radially innermost region of the guide groove (10). At the same position in the axial direction of the core, the circumferential width of the deformation zone (S) alternately decreases and increases along the radial outward direction.

2. The squirrel cage rotor core according to claim 1, characterized in that: At different positions in the axial direction, the distance from the radially innermost area of ​​the deformation zone (S) to the central axis of the core first decreases and then increases, or first increases and then decreases.

3. The squirrel cage rotor core according to claim 1 or 2, characterized in that: The deformation zone (S) comprises one or more circumferential recesses (11), so that the circumferential width of the deformation zone (S) gradually decreases and increases in the radially outward direction.

4. The squirrel cage rotor core according to claim 1 or 2, characterized in that: The deformation zone (S) comprises one or more circumferential protrusions (12), so that the circumferential width of the deformation zone (S) increases and decreases sequentially along the radial outward direction.

5. The squirrel cage rotor core according to claim 1, characterized in that: In a direction perpendicular to the axial direction of the core, the cross-sections of the core at all axial locations are the same.

6. The squirrel cage rotor core according to claim 3, characterized in that: In a direction perpendicular to the axial direction of the core, the cross-sections of the core at different axial locations are not completely the same. The iron core comprises at least one conventional stack (C1) and two special-shaped stacks (C2); the conventional stack (C1) is sandwiched by the two special-shaped stacks (C2) in the middle of the axial direction; the deformation zone (S) is only located in the special-shaped stack (C2); the guide slot (10) forms a conventional guide slot hole (101) in the area where the conventional stack (C1) is located; and the conventional guide slot hole (101) does not have the recess (11).

7. The squirrel cage rotor core according to claim 4, characterized in that: In a direction perpendicular to the axial direction of the core, the cross-sections of the core at different axial locations are not completely the same. The iron core comprises at least one conventional stack (C1) and two special-shaped stacks (C2); the conventional stack (C1) is sandwiched by the two special-shaped stacks (C2) in the middle of the axial direction; the deformation zone (S) is only located in the special-shaped stack (C2); the guide slot (10) forms a conventional guide slot hole (101) in the area where the conventional stack (C1) is located; and the conventional guide slot hole (101) does not have the convex portion (12).

8. The squirrel cage rotor core according to claim 1, characterized in that: The iron core comprises at least three conventional stacks (C1) and two special-shaped stacks (C2), wherein the conventional stack (C1), the special-shaped stack (C2), the conventional stack (C1), the special-shaped stack (C2) and the conventional stack (C1) are sequentially stacked from one end to the other end along the axial direction of the iron core. The guide groove (10) forms a conventional guide groove hole (101) in the area where the conventional stack (C1) is located, and forms a special-shaped guide groove hole (102) in the area where the special-shaped stack (C2) is located. The distance from the radial innermost area of ​​the special-shaped guide slot hole (102) to the central axis of the iron core is smaller than the distance from the radial innermost area of ​​the conventional guide slot hole (101) to the central axis of the iron core, or the distance from the radial innermost area of ​​the special-shaped guide slot hole (102) to the central axis of the iron core is larger than the distance from the radial innermost area of ​​the conventional guide slot hole (101) to the central axis of the iron core.

9. The squirrel cage rotor core according to claim 8, characterized in that: The axial dimension of the conventional stack (C1) located in the middle of the axial direction accounts for more than 80% of the axial dimension of the core.

10. A squirrel cage rotor, characterized in that It comprises an iron core (C) and a conductive bar, wherein the iron core (C) is the iron core according to any one of claims 1 to 9, and the conductive bar is embedded in the guide groove (10) of the iron core.

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