Rotor structure, motor and compressor

Abstract

The present disclosure provides a rotor structure, a motor, and a compressor. The rotor structure includes: a rotor core and a cage structure. The rotor core includes an axially arranged first core segment and a second core segment, the first core segment being provided with rotor skew slots, and the second core segment being provided with rotor straight slots. The cage structure includes an axially arranged first cage and a second cage, the first cage being provided within the rotor skew slots of the first core segment, and the second cage being provided within the rotor straight slots of the second core segment. The rotor structure disclosed herein has a two-end rotor core with straight and skew slots, which reduces harmonic loss and stray loss in cast aluminum during motor operation, while also weakening synchronous additional torque. The structure is simple, compact, and effective. Without changing the structural material, while ensuring that the motor's magnetic properties meet the requirements, the rotor core cage is changed in shape, transforming a single skewed cage into two axially parallel cages, thereby reducing the noise level of the asynchronous motor and improving the motor's efficiency.

Description

Technical Field

[0001] The present disclosure belongs to the technical field of electric motors, and particularly relates to a rotor structure, a motor, and a compressor. Background Art

[0002] Cage induction motors are widely used in compressors due to their simple structure, easy manufacturing, reliable operation, low price and convenient maintenance. Considering the processability, the traditional structure with straight stator slots and slanted rotor slots with one tooth pitch relative to the stator slots is generally adopted.

[0003] While rotor skew can provide a range of performance advantages, squirrel cage skew rotors have significant magnetic field leakage, increasing load stray losses and reducing motor efficiency. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present disclosure is that the magnetic field leakage of the squirrel cage skew slot rotor motor is large, which increases the load stray loss and thus reduces the motor efficiency, thereby providing a rotor structure, motor and compressor.

[0005] In order to solve the above problems, the present disclosure provides a rotor structure, comprising:

[0006] Rotor core and squirrel cage structure;

[0007] The rotor core includes an axially arranged first core segment and a second core segment, the first core segment is provided with a rotor skew slot, and the second core segment is provided with a rotor straight slot; the squirrel cage structure includes an axially arranged first squirrel cage and a second squirrel cage; the first squirrel cage is arranged in the rotor skew slot of the first core segment, and the second squirrel cage is arranged in the rotor straight slot of the second core segment.

[0008] The purpose of the present disclosure and the solution of its technical problems can be further achieved by adopting the following technical measures.

[0009] In some embodiments, the rotor core also includes a third core segment, and the squirrel cage structure also includes a slip ring. The third core segment is arranged between the first core segment and the second core segment, and axially separates the first core segment from the second core segment. The slip ring is arranged in the third core segment and is respectively connected to the first squirrel cage and the second squirrel cage.

[0010] In some embodiments, the first squirrel cage includes a first end ring and a first guide bar group, and the second squirrel cage includes a second end ring and a second guide bar group. One axial end of the first guide bar group is connected to the first end ring, and the other axial end passes through the rotor skew slot to be connected to the slip ring. One axial end of the second guide bar group is connected to the second end ring, and the other axial end passes through the rotor straight slot to be connected to the slip ring.

[0011] In some embodiments, the axial ends of the rotor skew slot and the rotor straight slot, which are close to each other, are staggered by a specific angle θ.

[0012] In some embodiments, the number of the rotor skew slots and the number of the rotor straight slots are both Z, and then θ=360 / Z.

[0013] In some embodiments, the axial length of the first core segment is H1, and the axial length of the second core segment is H2, satisfying 1.5 mm ≤ H2 / H1 ≤ 2 mm.

[0014] In some embodiments, the outer diameter of the first core segment is D1, and the outer diameter of the second core segment is D2, satisfying 0.3 mm ≤ D1 - D2 ≤ 1 mm.

[0015] In some embodiments, the outer diameter of the third core segment is d1, and the inner diameter of the rotor skew slot and the rotor straight slot is d2, satisfying d2-d1≥1mm.

[0016] In some embodiments, the outer diameter of the slip ring is d3, and the outer diameter of the second core segment is D2, satisfying 0.5 mm ≤ D2 - d3 ≤ 2 mm.

[0017] In some embodiments, the axial length of the slip ring is h, the tooth width of the rotor skew slot and the rotor straight slot is h2, and the axial length of the slip ring is h ... <h<1.5×h2。

[0018] A motor comprises the above-mentioned rotor structure and a stator structure, wherein the rotor skew slots are inclined in the axial direction of the first core segment by a stator tooth pitch.

[0019] A compressor comprises the above-mentioned rotor structure and a pump body assembly, wherein the first core segment is close to the pump body assembly and the second core segment is far away from the pump body assembly.

[0020] The rotor structure, motor, and compressor provided by the present disclosure have at least the following beneficial effects:

[0021] The rotor structure disclosed herein has a two-end rotor core with straight slots and oblique slots. After aluminum casting, an induction cage structure with axial series connection at both ends is formed, which reduces harmonic loss and stray loss in the cast aluminum during motor operation. At the same time, due to the special structure of the mixture of oblique slots and straight slots, the synchronous additional torque is weakened. The structure is simple, compact, and effective. Without changing the structural material, under the condition of ensuring that the magnetic performance characteristics of the motor are qualified, by changing the shape of the rotor core cage, the single oblique cage is transformed into two axially parallel cages, thereby reducing the noise level of the asynchronous motor and improving the motor efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the structure of the rotor core according to an embodiment of the present disclosure;

[0023] Figure 2 This is a schematic structural diagram of a squirrel cage structure according to an embodiment of the present disclosure;

[0024] Figure 3 is a cross-sectional view of a rotor core according to an embodiment of the present disclosure;

[0025] Figure 4 for Figure 3 Cross-section of the rotor core at AA in the middle;

[0026] Figure 5 for Figure 3 Cross-section of the rotor core at CC;

[0027] Figure 6 for Figure 3 Cross-section of the rotor core at the middle BB;

[0028] Figure 7 Schematic diagram of the rotor structure according to an embodiment of the present disclosure;

[0029] Figure 8 Schematic diagram of the dimensions of the rotor structure of an embodiment of the present disclosure.

[0030] The reference numerals indicate:

[0031] 1. Rotor core; 2. Squirrel cage structure; 3. First core segment; 4. Second core segment; 5. Rotor skew slots; 6. Rotor straight slots; 7. First squirrel cage; 8. Second squirrel cage; 9. Third core segment; 10. Slip ring; 11. First end ring; 12. First conductor bar group; 13. Second end ring; 14. Second conductor bar group; 15. Shaft hole. DETAILED DESCRIPTION

[0032] To make the objectives, technical solutions, and advantages of the present disclosure more clear, the technical solutions of the present disclosure will be clearly and completely described below in conjunction with the specific embodiments of the present disclosure and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present disclosure.

[0033] Combine Figures 1 to 8As shown, an embodiment of the present disclosure provides a rotor structure, comprising: a rotor core 1 and a cage structure 2; the rotor core 1 comprises an axially arranged first core segment 3 and a second core segment 4, a through axial hole 15 is provided in the middle of the rotor core 1, the first core segment 3 is provided with a rotor skew slot 5, and the second core segment 4 is provided with a rotor straight slot 6; the cage structure 2 comprises an axially arranged first cage 7 and a second cage 8; the first cage 7 is arranged in the rotor skew slot 5 of the first core segment 3, and the second cage 8 is arranged in the rotor straight slot 6 of the second core segment 4.

[0034] The rotor structure of the embodiment of the present disclosure has a two-end rotor core 1 with straight slots and oblique slots. After aluminum casting, an induction cage structure 2 with axial series connection at both ends is formed, which reduces the harmonic loss and stray loss in the cast aluminum when the motor is running. At the same time, due to the special structure of the mixture of oblique slots and straight slots, the synchronous additional torque is weakened. The structure is simple, compact and has obvious effects. Without changing the structural material, under the condition of ensuring that the magnetic performance characteristics of the motor are qualified, by changing the shape of the cage of the rotor core 1, the single oblique cage is transformed into two axial parallel cages, thereby reducing the noise level of the asynchronous motor and improving the motor efficiency.

[0035] In some embodiments, the rotor core 1 also includes a third core segment 9, which is an annular groove opened on the outer peripheral surface of the stator core. The squirrel cage structure 2 also includes a slip ring 10. The third core segment 9 is arranged between the first core segment 3 and the second core segment 4, and axially separates the first core segment 3 from the second core segment 4. The slip ring 10 is arranged in the third core segment 9 and is connected to the first squirrel cage 7 and the second squirrel cage 8 respectively.

[0036] In this embodiment, the third core segment houses the slip ring, which serves as the merging structure of the first and second cages and also as the supporting structure of the two cages in the middle of the rotor core. The slip ring is manufactured using the same aluminum casting process as the cage.

[0037] In some embodiments, the first squirrel cage 7 includes a first end ring 11 and a first conductor bar group 12, and the second squirrel cage 8 includes a second end ring 13 and a second conductor bar group 14. One axial end of the first conductor bar group 12 is connected to the first end ring 11, and the other axial end passes through the rotor skew slot 5 to be connected to the slip ring 10. One axial end of the second conductor bar group 14 is connected to the second end ring 13, and the other axial end passes through the rotor straight slot 6 to be connected to the slip ring 10.

[0038] The squirrel-cage structure 2 of this embodiment includes, in the axial direction in sequence, a first end ring 11, a first bar group 12, a collecting ring 10, a second bar group 14, and a second end ring 13, forming a complete current loop. The number of bars in the first bar group 12 is the same as the number of rotor skew slots 5, and the number of bars in the second bar group 14 is the same as the number of rotor straight slots 6. One bar is provided in each rotor skew slot 5 and rotor straight slot 6.

[0039] In some embodiments, at the axial ends where the rotor skew slots 5 and the rotor straight slots 6 are close to each other, they are offset by a specific angle θ. Preferably, the number of both the rotor skew slots 5 and the rotor straight slots 6 is Z, then θ = 360 / Z. In the rotor structure of this embodiment, the rotor skew slots 5 and the rotor straight slots 6 are staggered, which has the effect of reducing the transverse current eddy in the collecting ring.

[0040] In some embodiments, the axial length of the first core segment 3 is H1, and the axial length of the second core segment 4 is H2, satisfying 1.5 mm ≤ H2 / H1 ≤ 2 mm. The outer diameter of the first core segment 3 is D1, and the outer diameter of the second core segment 4 is D2, satisfying 0.3 mm ≤ D1 - D2 ≤ 1 mm. When the structure of the rotor core 1 meets the above size requirements, it can increase the end air gap, reduce the air gap non-uniformity formed by the crankshaft bending during operation, as well as the electromagnetic force fluctuation generated by it, and reduce the noise level of the whole machine.

[0041] In some embodiments, the outer diameter of the third core segment 9 is d1, and the inner diameters of the rotor skew slots 5 and the rotor straight slots 6 are d2, satisfying d2 - d'1 ≥ 1 mm. In the rotor core of this embodiment, when the outer diameter of the third core segment 9 and the inner diameter of the rotor slots meet the above requirements, it has the effect of making full use of the squirrel-cage bars.

[0042] In some embodiments, the outer diameter of the collecting ring 10 is d3, and the outer diameter of the second core segment 4 is D2, satisfying 0.5 mm ≤ D2 - d3 ≤ 2 mm. Thus, the outer surface of the collecting ring 10 of this embodiment is smaller than the outer diameter of the rotor core. Since the strong fluctuation of the stator-rotor air gap will form eddy currents on the surface of the conductive material, the surface of the cast-aluminum collecting ring is lower than the surface of the rotor core, reducing the magnetic field strength at this place and effectively reducing the induced current on the surface of the collecting ring and the eddy current loss generated thereby.

[0043] In some embodiments, the axial length of the collecting ring 10 is h, and the tooth width of the rotor skew slots 5 and the rotor straight slots 6 is h2, satisfying 0.5×h2 < h < 1.5×h2. In the rotor core of this embodiment, when the size of the collecting ring 10 and the tooth width of the rotor slots meet the above requirements, it has the effect of ensuring that the current density of the collecting ring is within a reasonable range.

[0044] In the rotor structure of the embodiment disclosed herein, the three-section rotor core 1 is completed by stamping and laminating, and then end rings, guide bars and slip rings 10 are formed at both ends of the rotor, the rotor slots and the middle third core shaft by casting aluminum, that is, the first squirrel cage 7, the slip ring 10 and the second squirrel cage 8, thereby completing the cast aluminum squirrel cage of the rotor.

[0045] In the rotor structure of the embodiment of the present disclosure, the number of rotor straight slots 6 and rotor skew slots 5 on the rotor core 1 can be freely selected as needed, and the slot shape can also be an elliptical slot, a circular slot, a T-shaped slot, etc.

[0046] An embodiment of the present disclosure further provides a motor, comprising the above-mentioned rotor structure and a stator structure, wherein the rotor skew slots 5 are tilted in the axial direction of the first core segment 3 by a stator tooth pitch.

[0047] The motor of the disclosed embodiment can eliminate the influence of stator tooth harmonics by designing the rotor skew slots 5, preventing the motor from falling into a speed pit during startup and failing to reach a normal speed. At the same time, it also has all the technical effects of the rotor structure disclosed in the disclosure.

[0048] The present disclosure provides a compressor comprising the aforementioned rotor structure and a pump assembly, wherein the first core segment 3 is located adjacent to the pump assembly and the second core segment 4 is located distal to the pump assembly. Consequently, the compressor of this embodiment has the advantages of low noise levels and high motor efficiency.

[0049] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0050] The above are merely preferred embodiments of the present disclosure and are not intended to limit the present disclosure. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present disclosure shall be included within the scope of protection of the present disclosure. The above are merely preferred embodiments of the present disclosure. It should be noted that those skilled in the art may make several improvements and variations without departing from the scope of protection of the present disclosure, and such improvements and variations shall also be considered within the scope of protection of the present disclosure.

Claims

1. A motor, characterized in that: include: A rotor core (1), a squirrel cage structure (2); The rotor core (1) comprises an axially arranged first core segment (3) and a second core segment (4), wherein the first core segment (3) is provided with a rotor skew slot (5), and the second core segment (4) is provided with a rotor straight slot (6); the squirrel cage structure (2) comprises an axially arranged first squirrel cage (7) and a second squirrel cage (8); the first squirrel cage (7) is arranged in the rotor skew slot (5) of the first core segment (3), and the second squirrel cage (8) is arranged in the rotor straight slot (6) of the second core segment (4); The rotor core (1) further comprises a third core segment (9), and the cage structure (2) further comprises a slip ring (10), wherein the third core segment (9) is arranged between the first core segment (3) and the second core segment (4), and axially separates the first core segment (3) from the second core segment (4), and the slip ring (10) is arranged in the third core segment (9) and connected to the first cage (7) and the second cage (8) respectively; The first squirrel cage (7) includes a first end ring (11) and a first guide bar group (12); the second squirrel cage (8) includes a second end ring (13) and a second guide bar group (14); one axial end of the first guide bar group (12) is connected to the first end ring (11), and the other axial end passes through the rotor skew slot (5) and is connected to the slip ring (10); one axial end of the second guide bar group (14) is connected to the second end ring (13), and the other axial end passes through the rotor straight slot (6) and is connected to the slip ring (10); Along the axial direction of the rotor core (1), the first end ring (11), the first conductor bar group (12), the slip ring (10), the second conductor bar group (14), and the second end ring (13) are sequentially arranged to form a complete current loop; the outer diameter of the slip ring (10) is d3, and the outer diameter of the second core segment (4) is D2, satisfying 0.5 mm ≤ D2 - d3 ≤ 2 mm; The motor further comprises a stator structure, wherein the rotor skew slots (5) are inclined in the axial direction of the first core segment (3) by a stator tooth pitch; The axial length of the first core segment (3) is H1, and the axial length of the second core segment (4) is H2, satisfying 1.5 mm ≤ H2 / H1 ≤ 2 mm; the outer diameter of the first core segment (3) is D1, and the outer diameter of the second core segment (4) is D2, satisfying 0.3 mm ≤ D1-D2 ≤ 1 mm.

2. The motor according to claim 1, characterized in that The axial ends of the rotor skew slot (5) and the rotor straight slot (6) that are close to each other are staggered at a specific angle θ.

3. The motor according to claim 2, characterized in that The number of the rotor skew slots (5) and the number of the rotor straight slots (6) are both Z, and then θ=360 / Z.

4. The motor according to claim 1, characterized in that The outer diameter of the third core segment (9) is d1, and the bottom diameter of the rotor skew slot (5) and the rotor straight slot (6) is d2, satisfying d2-d1≥1mm.

5. The motor according to claim 1, characterized in that The axial length of the merge ring (10) is h, and the tooth width of the rotor skew slot (5) and the rotor straight slot (6) is h2, satisfying 0.5×h2≤h≤1.5×h2.

6. A compressor, characterized in that: The motor comprises the motor according to any one of claims 1 to 5, and further comprises a pump body assembly, wherein the first core segment (3) is close to the pump body assembly, and the second core segment (4) is far away from the pump body assembly.

Images