Double-Convex Roller Bearing for Wind Turbine Load Management

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Solution Overview

Problem

Existing rolling bearings, particularly in wind turbines, face challenges in managing increasing loads while maintaining a compact and lightweight design, as larger rotor blades generate higher wind forces and tilting moments, requiring improved load capacity without increasing the bearing's cross-sectional size and weight.

Innovation Solution

The design incorporates rolling elements with double-convex outer surfaces and a specific curvature, allowing for high axial force absorption and tilting moment handling while minimizing the bearing's size and weight, featuring a nose ring and C-ring configuration with overlapping rows of rolling elements for precise guidance and reduced friction, and an additional radial bearing for transmitting radial forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the size of the rolling elements is increased to make the rolling bearing more stable and handle higher loads, then the load capacity is improved, but the ring cross section and overall weight of the bearing increase

Engineering Contradiction:
Improveload capacityVSAvoidbearing weight
Core Design Contradiction:
StrengthVSWeight of stationary object

Solution Approach 1:

The rolling elements feature a double-convex outer surface with specific curvature radii (rq < rmax). This curved geometry allows the rolling elements to handle both axial and radial loads more efficiently than cylindrical rollers, increasing load capacity without requiring larger dimensions. The curvature enables better stress distribution and contact mechanics, resolving the contradiction between load capacity and size/weight.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Strength

If the ring cross section is increased to handle higher wind forces and tilting moments, then the load capacity is improved, but the weight of the bearing increases, straining the main bearing and preventing smooth startup

Engineering Contradiction:
Improveload capacityVSAvoidbearing weight
Core Design Contradiction:
StrengthVSWeight of stationary object

Solution Approach 1:

The invention changes the geometric parameters of the rolling elements, specifically the double-convex shape with controlled curvature radii (rq < rmax) and length-to-diameter ratio (l < 2rmax). These parameter changes enable the rolling elements to withstand higher loads and tilting moments while maintaining a compact cross-section, thus increasing load capacity without proportionally increasing weight.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The double-convex curved surface of the rolling elements optimizes contact mechanics with the raceways, enabling efficient transmission of axial and radial forces. This curvature geometry allows the bearing to handle higher wind forces and tilting moments without requiring a larger cross-section, resolving the contradiction between strength and weight.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Strength

If multiple rows of rolling elements are added to handle both axial and radial loads, then the load capacity is improved, but the axial construction and weight increase

Engineering Contradiction:
Improveload capacityVSAvoidaxial construction
Core Design Contradiction:
StrengthVSLength of stationary object

Solution Approach 1:

The rolling elements with double-convex outer surfaces serve multiple functions simultaneously: they handle axial loads through their curved contact surfaces, radial loads through their rotational symmetry, and tilting moments through their geometric configuration. This multi-functionality eliminates the need for separate bearing rows for different load directions, reducing axial construction while maintaining comprehensive load capacity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

This configuration enhances load capacity, reduces friction and vibration, and minimizes the bearing's size and weight, enabling efficient energy use and smooth startup in wind turbines by effectively managing high wind and weight forces.

Implementation Method 1

at least one raceway is arranged in mutually radially overlapping areas of the gap on each of the two connecting elements, on which one or more rows of rolling elements roll

Methodology Applied
Scientific EffectRolling motion: Roller

Implementation Method 2

said rolling bodies having a double-convex outer surface with a transverse curvature radius rq in a direction tangential to the rotational symmetry axis z, which corresponds to the respective distance rR of the lateral surface to the rotational symmetry axis z

Methodology Applied
Scientific EffectCurvature effect:

Data Source

PatentEP2944836B1Roller bearing
Publication Date: 2017.10.04 IMO HOLDING GMBH
  • EP2944836B1 patent drawingFigure 1
  • EP2944836B1 patent drawingFigure 2~3
  • EP2944836B1 patent drawingFigure 4a~4c

AI summary

The invention relates to a rolling bearing with two annular connecting elements, concentric to each other and spaced apart by a gap, for connection to a first machine or plant part on the one hand and to a second machine or plant part, chassis, or foundation on the other, wherein at least one series of rolling elements is arranged in the gap, which roll between raceways on each of the two connecting elements, wherein the surface of said rolling elements is rotationally symmetrical only with respect to a single, distinguished axis of rotational symmetry, and wherein the rolling elements have a length in the direction of the axis of rotational symmetry and a maximum radius radially to the axis of rotational symmetry, as well as a doubly curved surface, wherein the doubly curved surface of the rolling elements has a longitudinal radius of curvature in a direction parallel to the axis of rotational symmetry, which corresponds to the maximum radius of the rolling element.and where half the length of the rolling element is smaller than the longitudinal radius of curvature of the rolling element.