Motor rotor

Abstract

The invention discloses a motor rotor which comprises a rotating shaft, a conducting bar, an iron core, a first end ring and a second end ring. The iron core is fixedly arranged on the rotating shaft; a conducting bar groove is formed in the iron core in the axial direction of the rotating shaft; the conducting bars are arranged in the conducting bar grooves in a penetrating manner and axially extend out of the two ends of the iron core; the first end ring is fixedly connected to one end of the guide strip; the second end ring is fixedly connected to the other end of the guide strip; a rolling section is formed on the conducting bar, and the rolling section is in interference fit with the port of the conducting bar groove so as to fix the conducting bar and the iron core. Compared with the prior art, the motor rotor disclosed by the invention has the advantages that through the design of additionally arranging the guide bar rolling sections and utilizing the guide bars as mechanical locking pieces, the problem of movement of a squirrel cage of the squirrel cage motor rotor is effectively prevented, the motor vibration caused by the balance problem of the rotor is avoided, the fracture frequency of the guide bars is reduced, and the service life of the motor rotor is prolonged. Therefore, the operation reliability of the motor is improved.

Description

Technical Field

[0001] This application relates to the field of electric motor technology, and more specifically, to an electric motor rotor. Background Technology

[0002] AC asynchronous motors are widely used in industrial production, especially in thermal power plants, as the kinetic energy output of rotating machinery due to their advantages of simple structure, low cost, and high reliability. An AC asynchronous motor mainly consists of a stator and a rotor. The rotor is the rotating part of the motor; it generates electromagnetic torque under the influence of the rotating magnetic field of the stator and drives the load to rotate. The squirrel-cage rotor is one of the most widely used rotor types. Its conductor bars and end rings form a closed loop resembling a squirrel cage; this closed loop is called the squirrel cage.

[0003] During use, under conditions of long-term operation, frequent start-stop, or drastic load changes, squirrel-cage rotor motors are prone to squirrel cage movement due to the alternating effects of thermal stress, electromagnetic force, and centrifugal force. This can lead to rotor balance problems, motor vibration, or breakage of copper bars at the end rings, ultimately affecting the reliability of the motor.

[0004] Therefore, how to reduce the squirrel cage movement of the motor rotor has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this application is to disclose an electric motor rotor to reduce squirrel cage movement in the electric motor rotor.

[0006] An electric motor rotor includes: a shaft, guide bars, an iron core, a first end ring, and a second end ring;

[0007] The iron core is fixedly mounted on the rotating shaft; a guide bar groove is formed in the iron core along the axial direction of the rotating shaft; the guide bar passes through the guide bar groove and extends axially from both ends of the iron core; a first end ring is fixedly connected to one end of the guide bar; a second end ring is fixedly connected to the other end of the guide bar.

[0008] The guide bar has a compaction section, which is interference-fitted with the end of the guide bar groove to fix the guide bar to the iron core.

[0009] In one possible implementation, the maximum cross-sectional area of ​​the compaction section is greater than the cross-sectional area of ​​the guide groove, and the cross-section of the compaction section is parallel to the plane containing the cross-section of the rotating shaft.

[0010] In one possible implementation, along the axial direction of the rotating shaft, the compaction section includes a middle section and an end section, wherein the cross-sectional area of ​​the middle section is larger than the cross-sectional area of ​​the end section.

[0011] In one possible implementation, the iron core is provided with multiple sets of air ducts along the axial direction of the rotating shaft; the rolling section is formed on the guide bar within the air duct.

[0012] In one possible implementation, multiple compaction sections are evenly arranged along the axial direction of the rotating shaft.

[0013] One possible implementation further includes a positioning block disposed between the target end ring and the iron core, wherein the target end ring is at least one of the first end ring and the second end ring;

[0014] One end of the positioning block is connected to the target end ring and / or at least one of the guide bars, and the other end abuts against the iron core.

[0015] In one possible implementation, a positioning groove is formed between the two positioning blocks, and the guide strip is disposed within the positioning groove.

[0016] In one possible implementation, multiple positioning blocks are evenly arranged in the circumferential direction of the rotating shaft.

[0017] In one possible implementation, the end of the iron core is provided with a toothed pressure plate, which is used to press the iron core, and the positioning block abuts against the toothed pressure plate.

[0018] In one possible implementation, insulating varnish is filled between the iron core and the conductor bar.

[0019] The electric motor rotor disclosed in this application forms a compacted section by rolling and deforming the guide bars. This compacted section is interference-fitted with the end of the guide bar groove to achieve axial mechanical locking between the guide bars and the iron core. The guide bars are fixedly connected to the first end ring and the second end ring to form a squirrel cage, which firmly locks the guide bars to the iron core, preventing axial movement of the guide bars and thus preventing movement of the squirrel cage.

[0020] Compared with related technologies, the electric motor rotor disclosed in this application, by adding a guide bar crushing section, uses the guide bar itself as a mechanical locking element, which effectively prevents the squirrel cage of the squirrel cage motor rotor from moving around, avoids motor vibration caused by rotor imbalance, reduces the frequency of guide bar breakage, and thus improves the operational reliability of the motor. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of the electric motor rotor disclosed in the embodiments of this application;

[0023] Figure 2 This is a partially enlarged view of the motor rotor disclosed in the embodiments of this application.

[0024] The attached figures are labeled as follows:

[0025] 100. Iron core;

[0026] 200. Guide bar; 210. Compactor section;

[0027] 300, Positioning Block;

[0028] 400, First end ring;

[0029] 500, Second end ring;

[0030] 600. Shaft. Detailed Implementation

[0031] Under conditions of long-term operation, frequent start-stop, or drastic load changes, squirrel-cage rotor motors are prone to cage movement due to the alternating effects of thermal stress, electromagnetic force, and centrifugal force. The cause is analyzed as follows: after the motor starts, the copper bars generate significant heat during startup. Furthermore, copper has good ductility. Due to repeated starting and stopping, the squirrel-cage bars undergo repeated thermal expansion and contraction, resulting in a loss of interference fit between the copper bars and the iron core slots. This leads to a gap reappearing between the copper bars and the iron core slots. Once this gap appears, the copper bars vibrate during motor startup, causing overall squirrel cage displacement and bar breakage.

[0032] The electric motor rotor disclosed in this application is intended to solve the above-mentioned problems and reduce squirrel cage movement of the electric motor rotor.

[0033] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0034] See Figure 1 and Figure 2 The electric motor rotor disclosed in this application mainly includes a shaft 600, a guide bar 200, an iron core 100, a first end ring 400, and a second end ring 500.

[0035] The iron core 100 is made of stacked silicon steel laminations and is fixedly sleeved on the rotating shaft 600 by means of interference fit or key connection to achieve circumferential torque transmission and fixation. The iron core 100 has guide grooves, the extension direction of which is parallel to the axial direction of the rotating shaft 600. Multiple guide grooves are arranged circumferentially on the iron core 100.

[0036] The conductor bars 200 can be made of pure copper with high conductivity and high ductility, and multiple conductor bars 200 are inserted into the conductor bar grooves of the iron core 100. The two ends of the conductor bars 200 extend axially from the two ends of the iron core 100. The first end ring 400 and the second end ring 500 can be copper annular components, which are firmly welded to the ends of all conductor bars 200 by medium frequency brazing or high frequency induction welding, so that the conductor bars 200, the first end ring 400 and the second end ring 500 together form a complete squirrel cage-type conductive structure.

[0037] After the guide bars 200 and the iron core 100 are assembled, each guide bar 200 is rolled to form a rolled section 210. The rolling position can be on the guide bar 200 near the end of the guide bar groove, and the rolled section 210 is interference-fitted with the end of the guide bar groove to fix the guide bar 200 and the iron core 100. Specifically, a special hydraulic or pneumatic rolling tool can be used to deform a predetermined area of ​​the guide bar 200 to form the rolled section 210. The rolled section 210 forms mechanical interference with the guide bar groove of the iron core 100, forming a constraint structure on the end face of the iron core 100 to prevent relative movement between the guide bar 200 and the iron core 100, thereby effectively preventing axial movement of the squirrel cage and greatly improving the operating reliability of the rotor under complex working conditions.

[0038] It should be noted that the compaction sections 210 on different guide bars 200 are evenly arranged in the circumferential direction of the rotating shaft 600, thereby reducing the impact on the initial dynamic balance of the rotor. This helps to prevent the balance from being disrupted during operation due to uneven distribution of the compaction sections 210, ensuring the long-term stability of the rotor's dynamic balance throughout its entire life cycle and reducing vibration and noise.

[0039] The electric motor rotor disclosed in this application forms a rolling section 210 by the rolling deformation of the guide bar 200. The rolling section 210 is interference-fitted with the end of the guide bar groove to achieve axial mechanical locking between the guide bar 200 and the iron core 100. The guide bar 200 is fixedly connected with the first end ring 400 and the second end ring 500 to form a squirrel cage, which firmly locks the guide bar 200 to the iron core 100 and prevents the guide bar 200 from moving axially along the rotating shaft 600, thereby preventing the squirrel cage from moving.

[0040] Compared with related technologies, the electric motor rotor disclosed in this application, by adding a rolling section 210 and using the guide bar 200 itself as a mechanical locking element, effectively prevents the squirrel cage of the squirrel cage motor rotor from moving around, avoids motor vibration caused by rotor imbalance, reduces the frequency of breakage of the guide bar 200, and thus improves the operational reliability of the motor.

[0041] In one specific embodiment, the maximum cross-sectional area of ​​the compaction section 210 is larger than the cross-sectional area of ​​the guide groove, and the cross-section of the compaction section 210 is parallel to the plane containing the cross-section of the rotating shaft 600. Specifically, the compaction head of a compaction tool can be inserted from the side of the guide bar 200 facing away from the rotating shaft 600 and pressure can be applied radially inward along the rotating shaft 600. This pressure increases the cross-sectional area of ​​the compaction section 210, making it larger than the cross-sectional area of ​​the guide groove. The compaction section 210 and the guide groove form a physical interference, and the guide bar 200 and the iron core 100 are firmly locked together, preventing relative axial movement. As long as the compaction section 210 is not damaged, the axial movement of the guide bar 200 is prevented. This constraint does not rely on adhesives, friction, or other factors that may decay over time, and is not easily loosened, thus forming a reliable mechanical interference and axial locking.

[0042] In one embodiment, the compaction section 210 may be drum-shaped or spindle-shaped, and along the axial direction of the rotating shaft 600, the compaction section 210 includes a middle section and an end section, with the cross-sectional area of ​​the middle section being larger than that of the end section. The compaction section 210 has a smooth, continuously varying profile, gradually transitioning from the largest cross-section in the middle section to the smaller cross-section in the end section. This smooth transition allows for a gradual change in stress flow lines, avoiding peak stresses. This significantly improves the fatigue resistance of the compaction section 210 under long-term alternating loads, greatly extending the life of the guide bar 200. When the guide bar 200 is subjected to a unidirectional axial force attempting to move, the core 100 slides along the inclined surface of the compaction section 210, forcing the compaction section 210 to more tightly compress the surrounding material, transforming it into a self-tightening mechanism. The greater the applied axial force, the greater the clamping force, thereby enhancing the reliability of the constraint.

[0043] To facilitate rapid heat dissipation, multiple sets of air ducts 700 can be provided along the axial direction of the rotating shaft 600 in the iron core 100. These air ducts 700 can be annular spaces between the iron cores 100 for ventilation, thereby dissipating heat from the rotor. The compaction section 210 can be positioned on the guide bar 200 within the air duct 700, ensuring that both ends of the compaction section 210 engage with the iron core 100. This allows a single compaction section 210 to simultaneously resist axial forces in two directions, providing robust bidirectional axial constraint and achieving bidirectional axial positioning.

[0044] Based on the above design, multiple compaction sections 210 can be evenly arranged along the axial direction of the rotating shaft 600. This design provides multiple constraints, with multiple compaction sections 210 sharing the axial force, reducing the individual load, optimizing the load distribution, significantly reducing peak stress, and improving the reliability of the constraints.

[0045] To further improve reliability, the positioning block 300 can be welded before or after the rolling of the guide bar 200. The positioning block 300 is disposed between the target end ring and the iron core 100, wherein the target end ring is at least one of the first end ring 400 and the second end ring 500. One end of the positioning block 300 is connected to the target end ring and / or at least one of the guide bars 200, and the other end abuts against the iron core 100.

[0046] Taking the end where the first end ring 400 is located as an example, a positioning block 300 is welded onto the guide bar 200 located between the first end ring 400 and the end face of the iron core 100. This positioning block 300 can be a metal block, fixed to one side of the guide bar 200 by welding. During welding, the position of the positioning block 300 is controlled so that one side of it is in close contact with the end face of the iron core 100. In another implementation, the positioning block 300 can also be welded to the side of the first end ring 400 facing the iron core 100, with one side of the positioning block 300 in close contact with the end face of the iron core 100. This positioning block 300 prevents the entire squirrel cage structure (guide bar 200, first end ring 400, and second end ring 500) from moving towards the second end ring 500, providing axial constraint.

[0047] To achieve symmetrical bidirectional constraint, positioning blocks 300 can be welded to both the end of the same guide bar 200 connected to the first end ring 400 and the end connected to the second end ring 500. That is, positioning blocks 300 are arranged on both end faces of the iron core 100 to clamp the iron core 100 from both axial sides.

[0048] The positioning block 300 and the rolling section 210 together form a mechanism to prevent the rat cage from moving. The positioning block 300 can distribute the axial impact force more evenly to the guide bar 200 and the target end ring connected to it, avoiding the stress being completely concentrated in the rolling section 210, improving the impact resistance of the overall structure, and is suitable for occasions with extremely high reliability requirements.

[0049] In one specific implementation, the positioning blocks 300 can be arranged as follows: Figure 2As shown, a positioning groove is formed between the two positioning blocks 300, and the guide bar 200 is disposed within the positioning groove. Specifically, two positioning blocks 300 can be welded to two opposite sides of the same guide bar 200, which are opposite sides along the circumferential direction of the rotating shaft 600. The end faces of the two positioning blocks 300 directly contact and abut against the end face of the iron core 100 and the side of the target end ring. The two positioning blocks 300 securely lock the squirrel cage structure to the iron core 100 in the axial direction. This structure can effectively resist bidirectional axial forces and eliminate any possible axial movement gaps at the installation position. Axial impact forces or electromagnetic forces from two directions are transmitted to the iron core 100 and the target end ring respectively through the two positioning blocks 300, resulting in balanced force and a more stable and reliable structure.

[0050] To increase the reliability of the locating blocks 300 constraint, multiple locating blocks 300 can be evenly arranged along the circumference of the rotating shaft 600. For example, six locating block 300 mounting positions can be evenly arranged along the circumference of the rotating shaft 600, each mounting position including three guide bars 200 for welding the locating block 300. Symmetrically and evenly arranging multiple locating blocks 300 of the same mass on the circumference does not introduce new imbalances, making it easier for the rotor to achieve and maintain fine dynamic balance during initial manufacturing and subsequent maintenance. This design can evenly distribute axial impact forces to various points on the circumference, greatly reducing the force borne by each locating block 300 and its weld, significantly improving the reliability and fatigue life of the structure, and avoiding local compression and asymmetrical deformation, ensuring the overall rigidity and stability of the squirrel cage structure.

[0051] The iron core 100 has toothed pressure plates 110 at its ends, which are used to clamp the iron core 100. The iron core 100 is made of a large number of thin silicon steel laminations, and its integrity depends on the lamination pressure and processes such as riveting and welding. At both ends, especially in the toothed section between the two guide bar grooves, the laminations are the weakest, forming a cantilever beam shape. The toothed pressure plates 110 are separately machined integral ring-shaped components, usually much thicker than the laminations, with extremely high strength and rigidity. The toothed pressure plates 110 are placed at both ends of the iron core 100, providing a solid support for the entire end face through clamping force, thereby improving the structural rigidity and integrity of the iron core 100.

[0052] The positioning block 300 abuts against the toothed pressure plate 110, ensuring that the positioning block 300 contacts a hard, flat, and highly integral metal surface. This guarantees that the welding height of all positioning blocks 300 is consistent and the contact is uniform, thus ensuring the consistency and reliability of axial constraint. Moreover, the axial force is evenly distributed throughout the toothed pressure plate 110, and then transmitted from the toothed pressure plate 110 to the end face of the entire iron core 100, completely avoiding localized damage to the laminations caused by the positioning block 300.

[0053] In one specific embodiment, the core 100 can be vacuum impregnated and cured, filling the space between the core 100 and the conductor bars 200 with insulating varnish. The insulating varnish not only seals all surfaces and gaps, forming a protective barrier to effectively prevent the intrusion of moisture and contaminants, improving the core 100's resistance to moisture, mildew, salt spray, and chemical corrosion, but also forms a continuous, uniform, and robust insulating solid layer in the tiny gaps between the conductor bars 200 and the core 100, as well as between the laminations of the core 100. This significantly improves the rotor winding's insulation strength to ground, effectively preventing electrical breakdown faults and ensuring the safe operation of the motor. The cured insulating varnish firmly bonds the conductor bars 200, the insulating material, and the core 100 into a solid whole, enhancing structural rigidity and greatly reducing the vibration of the conductor bars 200 within the slots, thus solving the problem of conductor bar 200 vibration.

[0054] The terms "first" and "second," etc., used in the specification and claims of this application are used to distinguish different objects, not to describe a specific order, and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units may include steps or units not listed, but rather steps or units not listed. Additionally, in the description of embodiments in this application, "a plurality of" means two or more.

[0055] In the description of this application, it should be understood that the terms "height," "thickness," "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. In the description of this application, "a plurality of" means two or more, and "at least one" can mean one, two, or more, unless otherwise expressly specified.

[0056] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Specific technical means in some embodiments may be incorporated, in whole or in part, into another embodiment unless explicitly excluded by another embodiment. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An electric motor rotor, characterized in that, include: Shaft (600), guide bar (200), iron core (100), first end ring (400) and second end ring (500); The iron core (100) is fixedly disposed on the rotating shaft (600); along the axial direction of the rotating shaft (600), the iron core (100) is provided with a guide bar groove; the guide bar (200) passes through the guide bar groove and extends axially from both ends of the iron core (100); the first end ring (400) is fixedly connected to one end of the guide bar (200); the second end ring (500) is fixedly connected to the other end of the guide bar (200); The guide bar (200) has a rolling section (210) which is interference-fitted with the port of the guide bar groove to fix the guide bar (200) and the iron core (100).

2. The motor rotor as described in claim 1, characterized in that, The maximum cross-sectional area of ​​the compaction section (210) is greater than the cross-sectional area of ​​the guide groove, and the cross-section of the compaction section (210) is parallel to the plane containing the cross-section of the rotating shaft (600).

3. The motor rotor as described in claim 1, characterized in that, Along the axial direction of the rotating shaft (600), the compaction section (210) includes a middle section and an end section, the cross-sectional area of ​​the middle section being larger than that of the end section.

4. The motor rotor as described in claim 1, characterized in that, The iron core (100) is provided with multiple sets of air ducts (700) along the axial direction of the rotating shaft (600); the rolling section (210) is formed on the guide bar (200) inside the air duct (700).

5. The motor rotor as described in claim 4, characterized in that, The rolling section (210) is uniformly arranged in multiple sections along the axial direction of the rotating shaft (600).

6. The motor rotor as described in claim 1, characterized in that, It also includes a positioning block (300) disposed between the target end ring and the iron core (100), wherein the target end ring is at least one of the first end ring (400) and the second end ring (500); One end of the positioning block (300) is connected to the target end ring and / or at least one of the guide bars (200), and the other end abuts against the iron core (100).

7. The motor rotor as described in claim 6, characterized in that, A positioning groove is formed between the two positioning blocks (300), and the guide strip (200) is disposed in the positioning groove.

8. The motor rotor as described in claim 6, characterized in that, The positioning blocks (300) are evenly arranged in multiple directions along the circumference of the rotating shaft (600).

9. The motor rotor as described in claim 6, characterized in that, The iron core (100) is provided with a toothed pressure plate (110) at its end. The toothed pressure plate (110) is used to press the iron core (100) together. The positioning block (300) abuts against the toothed pressure plate (110).

10. The motor rotor as described in claim 1, characterized in that, The space between the iron core (100) and the conductor (200) is filled with insulating varnish.

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