Wind Turbine Bell Housing Recess Layout for Casting and Rigidity

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Solution Overview

Problem

Existing transmission bell housings for wind turbines face challenges in casting due to ribbed designs that compromise rigidity and vibration behavior.

Innovation Solution

A transmission bell housing with a toroid-shaped flange and recesses, featuring a constant wall thickness and strategically arranged diamond-shaped recesses to enhance casting ease and rigidity, while improving vibration behavior through non-integer recess distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If ribs are added to increase rigidity, then rigidity is improved, but casting difficulty increases

Engineering Contradiction:
ImproverigidityVSAvoidcasting ease
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The bell housing is divided into multiple wall sections with recesses created by removing material segments. This segmentation approach maintains rigidity through strategic reinforcement placement while eliminating the casting difficulties associated with continuous rib structures.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Recesses are strategically positioned in specific locations rather than uniformly distributed. This local quality approach allows rigidity to be enhanced only where structurally necessary, while maintaining casting ease in other areas by avoiding unnecessary complex geometries.

Inventive Principle:
Principle #3Local quality

2Strength

If recesses are added to improve mass-to-stiffness ratio, then rigidity is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvemass-to-stiffness ratioVSAvoidstructural complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The recesses are designed with asymmetric positioning and varying dimensions to optimize the mass-to-stiffness ratio. This asymmetric design allows for targeted structural reinforcement where needed while maintaining overall structural simplicity and manufacturability.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The recesses extend in multiple dimensional directions within the bell housing structure, creating three-dimensional voids that efficiently reduce mass while maintaining structural integrity. This dimensional approach provides superior stiffness-to-weight ratio compared to simple surface features.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Ease of manufacture

If standard recess distribution is used, then manufacturing is simplified, but vibration behavior deteriorates

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidvibration behavior
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The recesses are deliberately positioned asymmetrically with non-uniform spacing to avoid integer ratios that could resonate with operational frequencies. This asymmetric distribution disrupts potential vibration modes while maintaining manufacturing feasibility through standardized recess geometries.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The positioning parameters of the recesses are specifically optimized to achieve non-integer distribution patterns. By carefully controlling the angular and radial positions of each recess, the design achieves improved vibration characteristics while maintaining practical manufacturability.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3482074B1Bell housing for a wind turbine gear mechanism
Publication Date: 2022.07.20 ZF FRIEDRICHSHAFEN AG
  • EP3482074B1 patent drawingFigure 1a
  • EP3482074B1 patent drawingFigure 1b
  • EP3482074B1 patent drawingFigure 2

AI summary

The invention relates to a bell housing (101) having a first region (103) for securing in a nacelle of a wind turbine, a second region (105) for receiving a gear mechanism, and a wall (107); said wall (107) connecting the first region (103) and the second region (105) together. The wall (107) is provided with at least two recesses (109).