Squirrel cage rotor
By using the guard ring in the squirrel cage rotor, the connection between the guide bar and the end ring is solved, and the deformation and fracture problems at the connection caused by the increase in the motor rotor speed is improved, which improves performance and service life, while reducing manufacturing costs.
Patent Information
- Application Number
- CN202520738789.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-18
- Publication Date
- 2025-06-17
- Estimated Expiration
- 2035-04-18
AI Technical Summary
As the speed of the motor rotor increases, the risk of deformation, cracks and fractures at the connection between the squirrel cage guide bar and the end ring increases dramatically, resulting in a decrease in performance and a shortened service life.
A squirrel cage rotor is designed, and the yield strength of the material produced by the guard ring is greater than the yield strength of the material produced by the guard ring, and the casing of the guard ring is arranged at the end ring and the annular part to protect the connection between the guide strip and the end ring.
Through the protection of the guard ring, the deformation and breaking risks at the connection between the guide strip and the end ring are reduced, the performance and service life of the squirrel cage rotor is improved, and the manufacturing cost is reduced.
Smart Images
Figure CN222996407U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the technical field of motors, and particularly to a squirrel-cage rotor. Background Art
[0002] With the development of new energy vehicles, the requirement for the rotational speed of the motor rotor is getting higher and higher. For a cast-aluminum squirrel-cage rotor, as the rotational speed of the rotor increases, the risks of deformation, crack, and even fracture at the connection between the squirrel-cage bars and the end rings will increase sharply. This will seriously reduce the performance and service life of the squirrel-cage rotor. Summary of the Utility Model
[0003] The purpose of this application is to overcome or at least mitigate the deficiencies of the above-mentioned prior art, and provide a squirrel-cage rotor.
[0004] According to the first aspect of this application, a squirrel-cage rotor is provided, which includes an iron core and a squirrel cage. The squirrel cage includes a plurality of bars and end rings located at both ends of the bars. The bars are located in the bar slots of the iron core. Protective rings are provided at both ends of the iron core, and the yield strength of the material for manufacturing the protective rings is greater than the yield strength of the material for manufacturing the squirrel cage.
[0005] The protective ring includes a body portion, an annular portion, and a plurality of sleeves; through holes corresponding to and communicating with the bar slots one by one are provided in the body portion; the annular portion is located on the side of the body portion away from the end of the iron core and is sleeved on the end ring; the sleeves are located on the other side of the body portion and are sleeved on the bars.
[0006] In at least one embodiment, the outer peripheral wall of the sleeve fits with the inner peripheral wall of the bar slot.
[0007] In at least one embodiment, the thickness of the sleeve is not greater than the distance between the radial outside of the bar slot and the radial outside of the iron core, and is not less than 1 mm.
[0008] In at least one embodiment, the thickness of the outer side in the radial direction of the sleeve is greater than the thickness of the inner side in the radial direction of the sleeve.
[0009] In at least one embodiment, the sleeve is sleeved on the axial end of the bar, and the axial length of the sleeve is not less than 4 mm and not greater than 10 mm.
[0010] In at least one embodiment, the axial length of the annular portion is not less than 5 mm and not greater than the axial length of the end ring.
[0011] In at least one embodiment, the outer diameter of the annular portion is equal to the diameter of the iron core, and the inner diameter of the annular portion is not less than the diameter of the circle formed by enclosing the radial outside of all the sleeves.
[0012] In at least one embodiment, the thickness of the annular portion is equal to the distance between the radial outside of the bar slot and the radial outside of the iron core.
[0013] In at least one embodiment, the manufacturing material of the bar and the end ring is pure aluminum, and / or the manufacturing material of the retaining ring includes copper.
[0014] In at least one embodiment, the retaining ring is a stamping integral structure.
[0015] The beneficial technical effects brought by the technical solution provided by this application include:
[0016] In the squirrel-cage rotor provided by this application, the yield strength of the manufacturing material of the retaining ring is greater than that of the manufacturing material of the squirrel cage. By sleeving the sleeve of the retaining ring on the bar and the annular part on the end ring, the retaining ring plays a role in protecting the connection between the bar and the end ring, thereby reducing the risk of deformation and fracture at the connection, and helping to improve the performance and service life of the squirrel-cage rotor. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 is a schematic structural diagram of the squirrel-cage rotor provided by an embodiment of this application.
[0018] Figure 2 is Figure 1 an axial sectional schematic diagram of the shown squirrel-cage rotor.
[0019] Figure 3 is Figure 2 an enlarged schematic diagram at A in
[0020] Figure 4 is Figure 1 a schematic structural diagram of the iron core in the shown squirrel-cage rotor.
[0021] Figure 5 is Figure 1 a schematic structural diagram of the retaining ring in the shown squirrel-cage rotor.
[0022] Figure 6 is Figure 5 an axial sectional schematic diagram of the shown retaining ring.
[0023] Figure 7 is Figure 1 a schematic structural diagram of the shown squirrel-cage rotor after removing the squirrel cage.
[0024] Figure 8 is Figure 7 an axial sectional schematic diagram of the shown structure.
[0025] DESCRIPTION OF THE REFERENCE NUMERALS:
[0026] 10 - iron core; 11 - bar slot; 20 - squirrel cage: 21 - bar; 22 - end ring;
[0027] 30 - retaining ring; 31 - body part; 311 - through hole; 32 - annular part; 33 - sleeve; 40 - shaft hole. Detailed implementation manners
[0028] The exemplary implementation manners of the present application will be 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 application, rather than to exhaust all feasible manners of the present application, nor to limit the scope of the present application.
[0029] The technical solutions of the present application and how the technical solutions of the present application solve the above technical problems will be described in detail below with specific embodiments. It should be noted that the following implementation manners can be referenced, learned from, or combined with each other. For the same terms, similar features, and similar implementation steps in different implementation manners, they will not be described repeatedly.
[0030] Refer to Figures 1 to 8 to introduce the squirrel-cage rotor provided in this embodiment.
[0031] In this embodiment, the squirrel-cage rotor includes an iron core 10, a squirrel cage 20, and two retaining rings 30. The iron core 10 is formed with a plurality of axially penetrating bar slots 11. The squirrel cage 20 includes bars 21 having the same number as the bar slots 11, and each bar 21 is correspondingly installed in a bar slot 11. The squirrel cage 20 further includes two end rings 22, and one end ring 22 is provided at each axial end of the iron core 10, and both axial ends of the bar 21 are connected to one end ring 22 respectively.
[0032] In some implementation manners of the present application, the squirrel cage 20 is formed by casting. For example, the squirrel cage 20 is formed by casting with materials such as aluminum and aluminum alloy, so as to form an integrally formed squirrel cage 20, ensuring the connection strength between the bars 21 and the end rings 22.
[0033] As Figure 1 shown, one retaining ring 30 is provided at each axial end of the iron core 10. The retaining ring 30 is used to wrap part of the squirrel cage 20, especially the connection part between the bars 21 and the end rings 22 is wrapped by the retaining ring 30. Since the yield strength of the manufacturing material of the retaining ring 30 is greater than that of the manufacturing material of the squirrel cage 20, for example, the retaining ring 30 is formed by using pure copper or copper alloy, thus it can play a role in protecting the connection part, reducing the risk of deformation or even fracture at the connection part, and further improving the performance of the squirrel-cage rotor and extending the service life of the squirrel-cage rotor.
[0034] Moreover, without changing the structure of the existing iron core 10, the manufacturing cost of the squirrel-cage rotor is reduced.
[0035] In this embodiment, since the retaining ring 30 is provided, the conducting bars 21 and the end rings 22 can be formed by casting pure aluminum. Compared with the solution of casting the squirrel cage 20 with aluminum alloy material, using pure aluminum can greatly reduce the manufacturing cost and difficulty of the squirrel cage rotor, and can improve the production efficiency of the squirrel cage rotor. Among them, the pure aluminum is a material with an aluminum purity of 99.0%.
[0036] As Figure 3 shown, the body part 31 of the retaining ring 30 is located at the axial end of the iron core, the annular part 32 is sleeved on the outer peripheral wall of the end ring 22, and the sleeve 33 is sleeved on the outer peripheral wall of the end of the conducting bar 21. Thus, it plays a role in protecting the connection between the conducting bar 21 and the end ring 22.
[0037] In this embodiment, as Figure 5 and Figure 6 shown, the annular part 32 and the sleeve 33 are respectively located on both sides of the body part 31. The number of sleeves 33 in each retaining ring 30 is the same as the number of conducting bar slots 11, so that sleeves 33 are sleeved on both axial ends of each conducting bar 22.
[0038] Moreover, the axial length of the sleeve 33 is not less than 4 mm and not more than 10 mm. For example, the axial length of the sleeve 33 is 6 mm. With such a setting, while ensuring that the sleeve 33 can play a protective role, it can reduce the volume of the sleeve 33 occupying the conducting bar slot 11, ensure the volume of the conducting bar 21, and ensure the structural strength of the conducting bar 21. At the same time, it can reduce the manufacturing cost of the retaining ring 30.
[0039] Specifically, as Figure 5 shown, a hole that is connected to the shaft hole 40 of the rotor and has the same specifications (such as shape and area) is provided in the middle of the body part 31 to facilitate the passing of the rotating shaft.
[0040] The body part 31 is also provided with a plurality of through holes 311. The through holes 311 are provided at the radially outer side of the body part 31, and all the through holes 311 are circumferentially spaced apart along the body part 31, so that each through hole 311 is connected to a conducting bar slot 11.
[0041] The contour of the projection of the through hole 311 on the end face of the iron core 10 coincides with the contour of the conducting bar slot 11, that is, the specifications of the through hole 311 and the conducting bar slot 11 are the same. Each through hole 311 is correspondingly connected to a sleeve 33. After the sleeve 33 is inserted into the conducting bar slot 11, the outer peripheral wall of the sleeve 33 fits with the inner peripheral wall of the conducting bar slot 11 to ensure the connection strength between the retaining ring 30 and the iron core 10, and to facilitate the progress of the casting process for forming the squirrel cage 20.
[0042] It should be noted that for the squirrel-cage rotor provided in the embodiments of the present application, the iron core 10 and the retaining ring 30 are separately manufactured first, and then after they are assembled, they are placed into a casting mold, and the squirrel cage 20 is formed by pressure casting or centrifugal casting process. Therefore, in the embodiments of the present application, before the squirrel cage 20 is formed by casting, it is necessary to ensure the connection strength between the retaining ring 30 and the iron core 10 to avoid the situation that the retaining ring 30 moves during the casting process.
[0043] In this embodiment, the wall thickness of the sleeve 33 is equal at all circumferential positions, and the wall thickness of the sleeve 33 is not less than 1 mm to ensure that the sleeve 33 has sufficient yield strength.
[0044] In some embodiments of the present application, the wall thickness of the sleeve 33 is not equal at all circumferential positions. For example, it is set that the wall thickness of the outer side of the sleeve 33 in the radial direction is greater than the wall thickness of the inner side of the sleeve 33 in the radial direction. This is because during the operation of the rotor, the compressive stress received by the outer side of the bar 21 in the radial direction is usually greater than the tensile stress received by the inner side in the radial direction. Therefore, setting the wall thickness of the sleeve 33 in this way can improve the performance of the sleeve 33 in resisting compressive stress on the inner side in the radial direction, thereby further improving the protection ability of the sleeve 33 to the bar 21.
[0045] As Figure 3 shown, the outer peripheral wall of the end ring 22 is sleeved by the annular portion 32, that is, the axial length of the annular portion 32 is equal to the axial length of the end ring 22. Such a setting can not only strengthen the protection ability of the annular portion 32 to the end ring 22, but also the annular portion 32 can play a role of positioning and limiting during the casting process of the squirrel cage.
[0046] Of course, in some embodiments of the present application, the axial length of the annular portion 32 can be less than the axial length of the end ring 22, but the axial length of the annular portion 32 is not less than 5 mm. For example, the axial length of the annular portion 32 is 10 mm. In this way, while ensuring that the annular portion 32 can protect the end ring 22, the material used for the annular portion 32 can be reduced, and the manufacturing cost of the retaining ring 30 can be reduced.
[0047] In this embodiment, the thickness of the annular portion 32 is equal to the distance between the outer side in the radial direction of the bar groove 11 and the outer side in the radial direction of the iron core 10. This can ensure that the outer diameter of the annular portion 32 of the annular portion 32 is equal to the diameter of the iron core 10, so that the outer peripheral surface of the annular portion 32 is coplanar with the outer peripheral surface of the iron core 10, which can avoid the diameter of the squirrel-cage rotor from being too large and is convenient for ensuring the air gap between the squirrel-cage rotor and the stator in the motor.
[0048] In this embodiment, the inner diameter of the annular portion 32 is not less than the diameter of the circle formed by enclosing the outer sides in the radial direction of all the sleeves 33, so as to ensure that the outer side in the radial direction of the end ring 22 is not lower than the outer side in the radial direction of the bar 21 and ensure the connection strength between the end ring 22 and the bar 21.
[0049] In this embodiment, the retaining ring 30 is of an integrally formed structure. Specifically, the retaining ring 30 is of a stamping integrally formed structure, so as to improve the production efficiency of the retaining ring 30 while ensuring the overall structural strength of the retaining ring 30. Of course, in some embodiments of the present application, the retaining ring 30 can also be integrally formed by casting.
[0050] Since the retaining ring 30 is of a stamping integrally formed structure, in this embodiment, the wall thickness of the sleeve 33 can be the same as the thicknesses of the annular portion 32 and the body portion 31.
[0051] In some embodiments of the present application, the connection between the sleeve 33 and the body portion 31 is provided with a rounded corner, so as to increase the contact area at its connection with the bar 21 and the end ring 22. During the operation of the squirrel-cage rotor, the compressive stress at this place can be reduced, and the risk of fracture at the connection between the bar 21 and the end ring 22 can be reduced.
[0052] Applying the embodiments of the present application can at least achieve the following beneficial effects:
[0053] (1) By using a material with a yield strength greater than that of the manufacturing material of the squirrel cage to make a retaining ring that wraps part of the squirrel cage, the retaining ring can play a role in protecting the connection, reduce the risk of deformation and even fracture at the connection, and thus improve the performance of the squirrel-cage rotor and extend the service life of the squirrel-cage rotor.
[0054] (2) After the retaining ring and the iron core are assembled, the outer peripheral wall of the sleeve fits with the inner peripheral wall of the bar groove, which can ensure the connection strength between the retaining ring and the iron core and facilitate the casting process of forming the squirrel cage.
[0055] Of course, the present application is not limited to the above embodiments. Those skilled in the art can make various combinations and modifications to the above embodiments of the present application under the teaching of the present application without departing from the scope of the present invention.
[0056] For example, the number of through holes 311 is less than the number of bar grooves 11. Correspondingly, the area of the through holes 311 is larger than the area of the bar grooves 11. For example, each through hole 311 corresponds to two bar grooves 11.
[0057] For another example, the manufacturing material of the retaining ring 30 can also be stainless steel or DC die steel.
Claims
1. A squirrel cage rotor, comprising an iron core (10) and a squirrel cage (20), the squirrel cage (20) comprising a plurality of conductive bars (21) and end rings (22) located at both ends of the conductive bars (21), the conductive bars (21) being located in conductive bar slots (11) of the iron core (10), characterized in that: Guard rings (30) are provided at both ends of the iron core (10), and the yield strength of the material of which the guard rings (30) are made is greater than the yield strength of the material of which the cage (20) is made; The guard ring (30) comprises a main body (31), an annular portion (32) and a plurality of sleeves (33); the main body (31) is provided with through holes (311) corresponding to and communicating with the guide bar grooves (11) one by one; the annular portion (32) is located on a side of the main body (31) away from an end of the iron core (10) and is sleeved on the end ring (22); the sleeve (33) is located on the other side of the main body (31) and is sleeved on the guide bar (21).
2. The squirrel cage rotor according to claim 1, characterized in that: The outer peripheral wall of the sleeve (33) fits in contact with the inner peripheral wall of the guide groove (11).
3. The squirrel cage rotor according to claim 1, characterized in that: The thickness of the sleeve (33) is not greater than the distance between the radial outer side of the guide bar groove (11) and the radial outer side of the iron core (10), and is not less than 1 mm.
4. The squirrel cage rotor according to claim 1, characterized in that: The thickness of the radial outer side of the sleeve (33) is greater than the thickness of the radial inner side of the sleeve (33).
5. The squirrel cage rotor according to claim 1, characterized in that: The sleeve (33) is sleeved on the axial end of the guide bar (21); the axial length of the sleeve (33) is not less than 4 mm and not more than 10 mm.
6. The squirrel cage rotor according to claim 1, characterized in that: The axial length of the annular portion (32) is not less than 5 mm and not greater than the axial length of the end ring (22).
7. The squirrel cage rotor according to claim 1, characterized in that: The outer diameter of the annular portion (32) is equal to the diameter of the iron core (10), and the inner diameter of the annular portion (32) is not less than the diameter of a circular ring formed by the radial outer sides of all the sleeves (33).
8. The squirrel cage rotor according to claim 1, characterized in that: The thickness of the annular portion (32) is equal to the distance between the radial outer side of the guide bar groove (11) and the radial outer side of the iron core (10).
9. The squirrel cage rotor according to claim 1, characterized in that: The conductive bar (21) and the end ring (22) are made of pure aluminum, and / or the protective ring (30) is made of copper.
10. The squirrel cage rotor according to claim 1, characterized in that: The guard ring (30) is a stamped integrally formed structure.