Rotor structure for squirrel cage asynchronous motor

Abstract

The application belongs to the technical field of motor rotors, and particularly relates to a squirrel cage asynchronous motor rotor structure. The technical scheme is as follows: the squirrel cage asynchronous motor rotor structure comprises a rotating shaft, a plurality of rotating shaft open slots arranged along the axial direction are arranged on the rotating shaft, a squirrel cage strip is arranged in the rotating shaft open slot, an end ring is arranged on the end of the rotating shaft, a plurality of end ring open slots arranged along the axial direction are arranged in the end ring, the end of the squirrel cage strip is arranged in the end ring open slot, a guard ring for compressing the ends of the plurality of squirrel cage strips is arranged on the end ring, a plurality of squirrel cage strip holes arranged along the radial direction are arranged on the end of the squirrel cage strip, and an elastic pre-tightening element is arranged in the squirrel cage strip hole. The application provides a squirrel cage asynchronous motor rotor structure which can avoid welding and has reliable connection.

Description

Technical Field

[0001] This invention belongs to the field of electric motor rotor technology, and specifically relates to the rotor structure of a squirrel-cage asynchronous motor. Background Technology

[0002] Motors with a circumferential speed exceeding 200 m / s or a rotational speed exceeding 10,000 r / min are called high-speed motors. Large high-speed asynchronous motors have broad application prospects in high-speed grinding machines, air refrigeration systems, energy storage flywheels, fuel cells, natural gas transportation, and high-speed centrifugal compressors, and represent one of the development directions for asynchronous motors. The main characteristic of high-speed motors is their high rotor speed; conventional rotors cannot withstand the enormous centrifugal force, requiring special high-strength laminated or solid rotor structures. High-speed motors demand higher mechanical properties from the rotor, making rotor strength design a challenge. Currently, solid rotor designs are generally adopted. Commonly used solid rotor structures include radially slotted solid rotor structures, welded rectangular copper bar solid rotor structures, hot isostatic pressing welded solid rotor structures, and embedded copper bar solid rotor structures. These structures offer advantages in mechanical performance but also disadvantages such as long manufacturing cycles, high manufacturing costs, and difficulties in welding the squirrel cage bars and end rings. Summary of the Invention

[0003] In order to solve the above-mentioned problems in the prior art, the purpose of this invention is to provide a rotor structure for a squirrel-cage asynchronous motor that avoids welding and has a reliable connection.

[0004] The technical solution adopted in this invention is as follows:

[0005] The rotor structure of a squirrel-cage asynchronous motor includes a shaft with several axially arranged shaft opening slots. Squirrel cage bars are installed in the shaft opening slots. An end ring is fitted at the end of the shaft, and the end ring has several axially arranged end ring opening slots. The ends of the squirrel cage bars are located in the end ring opening slots. A retaining ring is fitted over the end ring to press the ends of the squirrel cage bars together. The ends of the squirrel cage bars have several radially arranged squirrel cage bar holes, and elastic preload elements are installed in the squirrel cage bar holes.

[0006] In this invention, the end of the cage bar is fitted into the opening groove of the end ring, and an elastic pre-tightening element is provided in the hole of the cage bar. The elastic pre-tightening element can expand the end of the cage bar, so that the cage bar and the end ring are fully tightened, and the cage bar, the end ring, the elastic pre-tightening element and the guard ring are fully pressed together, ensuring that the connection between the cage bar, the end ring and the guard ring is reliable and does not separate during operation.

[0007] In a preferred embodiment of the present invention, a limiting groove is provided inside the rotating shaft, which is arranged axially and communicates with the opening groove of the rotating shaft. A limiting protrusion is provided on the side of the cage bar, and the limiting protrusion is disposed in the limiting groove. The limiting protrusion of the cage bar is disposed in the limiting groove of the rotating shaft, so that the cage bar is reliably connected to the rotating shaft and the cage bar is prevented from becoming loose relative to the rotating shaft.

[0008] As a preferred embodiment of the present invention, the bottom of the rotating shaft opening groove and the bottom of the cage bar are both arc-shaped.

[0009] In a preferred embodiment of the present invention, a ventilation channel arranged axially is provided between the cage bars and the rotating shaft. By providing the ventilation channel, sufficient heat dissipation between the cage bars and the rotating shaft is ensured.

[0010] As a preferred embodiment of the present invention, a ventilation groove is provided inside the rotating shaft, and a ventilation channel is formed between the ventilation groove and the cage bar; or a cage bar groove is provided on the side of the cage bar, and a ventilation channel is formed between the cage bar groove and the inner wall of the rotating shaft opening groove.

[0011] In a preferred embodiment of the present invention, the cage bars are interference-fitted with the rotating shaft. Correspondingly, the limiting protrusion and the limiting groove are also interference-fitted, ensuring a reliable connection between the cage bars and the rotating shaft.

[0012] As a preferred embodiment of the present invention, the elastic preload element is a tapered pin or an open hollow pin.

[0013] As a preferred embodiment of the present invention, the material of the elastic preload element is copper.

[0014] In a preferred embodiment of the present invention, the cage bars, the elastic preload element, and the end ring are all interference-fitted with the retaining ring. The surfaces of the cage bar ends, the spring preload element, and the end ring are all in contact with the retaining ring. Through this interference fit, a reliable connection between the retaining ring and the cage bars, the elastic preload element, and the end ring can be ensured.

[0015] As a preferred embodiment of the present invention, the end ring is interference-fitted with the rotating shaft. The interference fit between the end ring and the rotating shaft ensures a reliable connection and prevents loosening during operation.

[0016] The beneficial effects of this invention are as follows:

[0017] In this invention, the end of the cage bar is fitted into the opening groove of the end ring, and an elastic pre-tightening element is provided in the hole of the cage bar. The elastic pre-tightening element can expand the end of the cage bar, so that the cage bar and the end ring are fully tightened, and the cage bar, the end ring, the elastic pre-tightening element and the guard ring are fully pressed together, ensuring that the connection between the cage bar, the end ring and the guard ring is reliable and does not separate during operation. Attached Figure Description

[0018] Figure 1This is a partial cross-sectional view of the present invention;

[0019] Figure 2 This is a right view of a portion of the structure of the present invention;

[0020] Figure 3 This is a partial sectional view of the shaft;

[0021] Figure 4 This is a schematic diagram of the structure of a rat cage bar;

[0022] Figure 5 This is a schematic diagram of the end ring structure;

[0023] Figure 6 This is a schematic diagram of the retaining ring structure;

[0024] Figure 7 This is a partial structural cross-sectional view of the bar structure and pivot of a rat cage.

[0025] Figure 8 This is a partial structural cross-sectional view of another type of mouse cage bars and pivot.

[0026] In the diagram: 1-rotating shaft; 2-squirrel cage bar; 3-end ring; 4-protective ring; 5-elastic pre-tightening element; 11-rotating shaft opening groove; 31-end ring opening groove; 21-squirrel cage bar hole; 12-limiting groove; 22-limiting protrusion; 13-ventilation groove; 23-squirrel cage bar groove. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0028] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the invention can be combined with each other.

[0029] like Figures 1-6As shown, a fan-shaped region is cut out with the center of the rotor structure as the reference. The rotor structure of the squirrel-cage asynchronous motor in this embodiment includes a shaft 1, a plurality of shaft opening slots 11 arranged along the axial direction on the shaft 1, a squirrel cage bar 2 arranged in the shaft opening slots 11, an end ring 3 sleeved on the end of the shaft 1, a plurality of end ring opening slots 31 arranged along the axial direction in the end ring 3, the ends of the squirrel cage bars 2 are arranged in the end ring opening slots 31, a retaining ring 4 for pressing the ends of the plurality of squirrel cage bars 2 is sleeved on the end ring 3, a plurality of squirrel cage bar holes 21 arranged along the radial direction are provided on the ends of the squirrel cage bars 2, and an elastic preload element 5 is arranged in the squirrel cage bar holes 21.

[0030] The elastic preload element 5 is a tapered pin or an open hollow pin. The material of the elastic preload element 5 is copper.

[0031] In this invention, the end of the cage bar 2 is fitted into the end ring opening groove 31, and an elastic pre-tightening element 5 is provided in the cage bar hole 21. The elastic pre-tightening element 5 can expand the end of the cage bar 2, so that the cage bar 2 and the end ring 3 are fully tightened, and the cage bar 2, the end ring 3, the elastic pre-tightening element 5 and the guard ring 4 are fully pressed together, ensuring that the connection between the cage bar 2, the end ring 3 and the guard ring 4 is reliable and does not separate during operation.

[0032] This invention solves the problems of difficult machining of closed slots in solid rotors, difficult welding of high-strength copper bars, and high thermal expansion stress of copper bars. Using common steel and copper materials, it has advantages such as simple structure, high mechanical strength, good heat dissipation, no welding required for copper bars, and low cost.

[0033] Specifically, the rotating shaft 1 is provided with a limiting groove 12 arranged axially and communicating with the rotating shaft opening groove 11. The side of the cage bar 2 is provided with a limiting protrusion 22, which is disposed within the limiting groove 12. The limiting protrusion 22 of the cage bar 2 being disposed within the limiting groove 12 of the rotating shaft 1 ensures a reliable connection between the cage bar 2 and the rotating shaft 1, preventing the cage bar 2 from becoming loose relative to the rotating shaft 1. The bottom of both the rotating shaft opening groove 11 and the bottom of the cage bar 2 are arc-shaped.

[0034] A ventilation channel arranged axially is provided between the cage bars 2 and the rotating shaft 1. This ventilation channel ensures sufficient heat dissipation between the cage bars 2 and the rotating shaft 1. Figure 7 As shown, in some embodiments, a ventilation groove 13 is provided inside the rotating shaft 1, and a ventilation channel is formed between the ventilation groove 13 and the cage bars 2. For example... Figure 8 As shown, in some other embodiments, a rat cage bar groove 23 is provided on the side of the rat cage bar 2, and a ventilation channel is formed between the rat cage bar groove 23 and the inner wall of the rotating shaft opening groove 11.

[0035] Furthermore, the cage bar 2 is interference-fitted with the rotating shaft 1, and the material of the rotating shaft 1 has a similar coefficient of linear expansion to that of the cage bar 2. Correspondingly, the limiting protrusion 22 and the limiting groove 12 are also interference-fitted, ensuring a reliable connection between the cage bar 2 and the rotating shaft 1. The cage bar 2, the elastic preload element 5, and the end ring 3 are all interference-fitted with the retaining ring 4. The surfaces of the ends of the cage bar 2, the spring preload element, and the end ring 3 are all in contact with the retaining ring 4. This interference fit ensures a reliable connection between the retaining ring 4 and the cage bar 2, the elastic preload element 5, and the end ring 3. The end ring 3 is interference-fitted with the rotating shaft 1. This interference fit ensures a reliable connection and prevents loosening during operation.

[0036] This invention is not limited to the above-described optional embodiments. Anyone can derive other various forms of products under the guidance of this invention. However, regardless of any changes made in their shape or structure, any technical solution that falls within the scope of the claims of this invention shall be protected by this invention.

Claims

1. A rotor structure for a squirrel-cage induction motor, characterized in that: Includes a rotating shaft (1), which is provided with a plurality of axially arranged rotating shaft opening slots (11), and a rat cage bar (2) is provided in the rotating shaft opening slots (11). An end ring (3) is sleeved on the end of the rotating shaft (1), and a plurality of axially arranged end ring opening slots (31) are provided in the end ring (3). The end of the rat cage bar (2) is provided in the end ring opening slots (31). The end ring (3) is sleeved with a protective ring (4) for pressing the end of the plurality of rat cage bars (2). The end of the rat cage bar (2) is provided with a plurality of radially arranged rat cage bar holes (21), and an elastic pre-tightening element (5) is provided in the rat cage bar holes (21). The rotating shaft (1) is provided with a limiting groove (12) arranged along the axial direction and communicating with the opening groove (11) of the rotating shaft. The side of the cage bar (2) is provided with a limiting protrusion (22), which is located in the limiting groove (12). A ventilation channel is provided between the cage bar (2) and the shaft (1) along the axial direction; a ventilation groove (13) is provided inside the shaft (1), and a ventilation channel is formed between the ventilation groove (13) and the cage bar (2); or a cage bar groove (23) is provided on the side of the cage bar (2), and a ventilation channel is formed between the cage bar groove (23) and the inner wall of the shaft opening groove (11).

2. The rotor structure of the squirrel-cage induction motor according to claim 1, characterized in that: The bottom of the rotating shaft opening groove (11) and the bottom of the cage bar (2) are both arc-shaped.

3. The rotor structure of the squirrel-cage asynchronous motor according to claim 1, characterized in that: The cage bars (2) are interference-fitted with the shaft (1).

4. The rotor structure of the squirrel-cage induction motor according to claim 1, characterized in that: The elastic preload element (5) is a tapered pin or an open hollow pin.

5. The rotor structure of the squirrel-cage asynchronous motor according to claim 1, characterized in that: The material of the elastic preload element (5) is copper.

6. The rotor structure of the squirrel-cage asynchronous motor according to claim 1, characterized in that: The cage bars (2), elastic pre-tightening element (5) and end ring (3) are all interference fit with the guard ring (4).

7. The rotor structure of the squirrel-cage asynchronous motor according to claim 1, characterized in that: The end ring (3) is interference-fitted with the rotating shaft (1).

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