Squirrel-Cage Rotor End Ring Reinforcement for High-Speed Stability
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Solution Overview
Problem
The short-circuit ring in squirrel-cage rotors of asynchronous machines deforms due to low material strength and significant shrinkage during cooling, leading to instability and deformation under centrifugal forces during operation.
Innovation Solution
A rotor design featuring a rotor core with grooves filled with electrically conductive material, where the grooves are formed into a short-circuit ring with a helix angle of 3° to 30°, and a support element with higher mechanical tensile strength is axially pressed onto the ring, providing stabilization and preventing deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the short-circuit ring is made with conventional materials and design, then the manufacturing is simple, but the material strength is insufficient causing deformation at high rotational speeds
Solution Approach 1:
The patent applies composite materials by combining a cast short-circuit ring (providing electrical conductivity and basic structure) with a separately manufactured reinforcement element (providing high mechanical strength). This composite structure resolves the contradiction by integrating materials with complementary properties to achieve both strength and manufacturability.
Solution Approach 2:
The short-circuit ring is segmented into two functional parts: the cast ring body and the reinforcement element. This segmentation allows each part to be optimized independently - the cast ring for electrical properties and the reinforcement element for mechanical strength - thereby resolving the contradiction between strength requirements and manufacturing simplicity.
2Stability of the object's composition
If the short-circuit ring is cast with a molded part for stabilization, then the initial positioning is improved, but the cast-in component no longer provides support after cooling due to shrinkage
Solution Approach 1:
The reinforcement element is preliminarily positioned in the end face during manufacturing, but its full stabilizing function is activated only after the cast ring cools and shrinks. This preliminary positioning ensures correct alignment while the operational support is provided by the thermally stable reinforcement element, resolving the contradiction between initial stability and operational reliability.
Solution Approach 2:
The reinforcement element acts as an intermediary between the shrinking cast ring and the required structural support. It mediates the dimensional changes during cooling while maintaining the short-circuit ring's stability, thereby ensuring both initial positioning and ongoing operational reliability.
3Power
If the short-circuit ring operates at high rotational speeds, then the power output is improved, but centrifugal forces cause deformation of the weak short-circuit ring
Solution Approach 1:
The composite structure of cast ring plus reinforcement element enables the short-circuit ring to withstand high centrifugal forces at elevated rotational speeds, thereby allowing higher power output without deformation.
Solution Approach 2:
The reinforcement element changes the mechanical parameter profile of the short-circuit ring, specifically increasing its resistance to centrifugal force. This parameter change enables operation at higher speeds and power levels without compromising structural integrity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively stabilizes the short-circuit ring, allowing for high-speed operation without deformation, with the rotor capable of operating at peripheral speeds exceeding 90 m/s and up to 150 m/s without risk of ring deformation, suitable for industrial and electric mobility applications.
Implementation Method 1
the short-circuit ring deforms at high rotational speeds... During operation, this results in deformation of the short-circuit ring due to centrifugal forces
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a rotor (11) of a dynamo-electric rotary machine (10), comprising: a rotor core (4) arranged concentrically relative to the rotor axis (6), wherein the rotor core (4) has grooves (3), wherein the grooves (3) are filled with at least one electrically conductive material; a front ring (2) arranged concentrically relative to the rotor axis (6) at the front axial end (8) of the grooves (3), wherein the front ring (2) has at least one electrically conductive material; a rear ring (2) arranged concentrically relative to the rotor axis (6) at the rear axial end (9) of the grooves, wherein the rear ring has at least one electrically conductive material, wherein a surface of the front and/or rear ring (2) facing away from the rotor core (3) at least partially has a bevel in the axial direction from an outer circumference (21) to an inner circumference (22) of the ring with a bevel angle (α); and at least one support element (1), wherein the support element (1) is designed in such a way that the support element (1) is at least partially interlockingly connected to the ring (2). The invention also relates to a dynamo-electric rotary machine (10), as well as a method for producing a rotor.