Electric Machine Labyrinth Seal With Speed-Adaptive Clearance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional sealing solutions for electric machine output shafts, such as labyrinth seals and friction seals, fail to provide sufficient tightness and have limited lifespan, especially in extreme conditions, and are not suitable for high-speed applications due to heating issues and imperfect sealing against fluids at standstill.
Innovation Solution
A sealing arrangement featuring a structurally continuous zig-zag labyrinth seal with a second seal made of elastic material and spring components, which converts to a clearance seal at high speeds to reduce friction and heat, and includes a dust and particle seal, limiter, lubricant transfer hole, and O-ring to enhance sealing effectiveness and longevity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional radial seals are used for high-speed applications, then sealing effectiveness is maintained, but friction causes heating which limits their use
Solution Approach 1:
The seal is divided into multiple zig-zag sections (110) forming a labyrinth structure, creating multiple narrow channels instead of a single contact interface. This segmentation reduces frictional heating by distributing the sealing function across multiple non-contacting surfaces while maintaining sealing effectiveness through the complex path geometry.
Solution Approach 2:
A dust and particle seal (200) made of friction material is introduced as an intermediary element between the labyrinth seal and the shaft. This sacrificial seal absorbs friction and wear, protecting the main labyrinth seal structure while allowing high-speed operation with minimal heat generation in the critical sealing zones.
2Reliability
If conventional labyrinth seals are used, then structure is simple, but sealing against fluids at standstill is imperfect
Solution Approach 1:
The second seal (112) with elastic material part (114) and spring part (116) provides dynamic sealing adaptation. At standstill or low speeds, the spring force presses the elastic seal against the surface to prevent fluid leakage. At high speeds, centrifugal force overcomes the spring force, allowing the seal to retract and convert to clearance seal mode, enabling operation across the full speed range.
Solution Approach 2:
The sealing mechanism changes its operational parameters based on speed conditions. The second seal transitions from a contact-based sealing mode (reliant on spring force and elastic deformation) at low speeds to a clearance-based sealing mode (reliant on centrifugal force and geometric clearance) at high speeds, optimizing performance for each operational regime.
3Reliability
If a second seal with spring part is added to the labyrinth seal, then sealing effectiveness is improved, but device complexity increases
Solution Approach 1:
The second seal (112) combines multiple functions into a single integrated component: the elastic material part provides sealing contact, the spring part provides restoring force, and the centrifugal force response provides speed-adaptive operation. This merging of functions into one component achieves enhanced sealing performance without proportionally increasing overall device complexity.
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 provides improved sealing efficiency and longevity by reducing friction and heat, preventing fluid and particle ingress, and maintaining effective lubrication, even at high speeds and in extreme conditions.
Implementation Method 1
the second seal (112) comprises an elastic material part (114) which is pressed, by the spring part (116) in the radial direction, against a surface (118) of the second part (102) at rotational speeds a centrifugal force of which to the second seal (112) is weaker than a spring force of the spring part (116)
Implementation Method 2
opening a gap (120) between the elastic material part (114) and said surface (118) at rotational speeds the centrifugal force of which to the second seal (112) is greater than the spring force of the spring part (116)
Implementation Method 3
A plurality of zig-zag sections (110) of a structurally continuous labyrinth seal (108) in a radial direction of the electric machine (10) between the first and second parts (102, 104)
Implementation Method 4
The radial outer end of the channel of the labyrinth seal (108) may include a dust and particle seal (200) between the radial outer end of the labyrinth seal (108) and the second seal (112), the dust and particle seal (200) preventing dust and particles from entering the channel of the labyrinth seal (108)
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A sealing arrangement for an electric machine, which is between a first part (104) attached to a rotatable shaft (106) and a second part (102) immobile with respect to a stator of the electric machine (10) comprises a plurality of zig-zag sections (110) of a channel of a labyrinth seal (108) in a radial direction of the electric machine (10). The channel of the labyrinth seal (108) includes a second seal (112) which is fixedly attached to the first part (104) and which has an elastic material part (114), the second seal (112) is pressed in the radial direction against a surface (118) of the second part (102), a normal of which has a component parallel to the radial direction, at rotational speeds a centrifugal force of which to the second seal (112) is weaker than a spring force of the second seal (112), and the second seal (112) opening a gap (120) between the second seal (112) and said surface (118) at rotational speeds the centrifugal force of which to the second seal (112) is greater than the spring force of the second seal (112).