Planetary Carrier Tilt Segments for Axial Load Compensation

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Solution Overview

Problem

Existing transmission arrangements for wind turbines face challenges in effectively supporting axial loads while ensuring easy assembly and maintaining low frictional resistance, particularly in compensating for uneven load distribution and tilting moments in planetary gear sets.

Innovation Solution

The transmission arrangement incorporates a planetary gear set with tilting pads on the planetary carrier, featuring a T-shaped contour, a spring element, and a hard coating for low friction and wear resistance, along with a securing element to prevent misalignment and ensure flexible axial support, which absorbs axial forces and tilts to maintain contact with the planet gears.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If tilting segments are provided on the planetary carrier to counteract tilting moments, then axial support effectiveness is improved, but device complexity increases

Engineering Contradiction:
Improveaxial support effectivenessVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The bearing support surface is segmented into multiple tilting segments (at least two) that can independently tilt relative to the planetary carrier. This segmentation allows each segment to adapt to local load conditions and tilting moments, improving axial support effectiveness while keeping individual segments simple in structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The tilting segments are designed to be dynamically tiltable rather than fixed, allowing them to adjust their orientation in response to varying axial loads and tilting moments. This dynamic capability enables the bearing to automatically compensate for uneven load distribution without requiring complex external control mechanisms.

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If the free end of the tilting segment protrudes completely into the recess, then assembly precision is improved, but ease of operation deteriorates due to restricted flexibility

Engineering Contradiction:
Improveassembly precisionVSAvoidflexibility
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The recess is designed with non-uniform clearance: in the radial direction (affecting assembly precision), the clearance is limited to allow precise positioning of the tilting segment, while in the tangential direction (affecting flexibility), a larger clearance is provided to enable the spring element to accommodate tangential deflections and maintain operational flexibility.

Inventive Principle:
Principle #3Local quality

3Reliability

If a securing element is introduced to prevent misalignment, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvealignment stabilityVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The spring element serves dual functions: it provides elastic support for axial loads and simultaneously acts as a securing element that prevents misalignment of the tilting segment. This self-service approach eliminates the need for separate alignment fixation mechanisms, maintaining reliability while avoiding additional components.

Inventive Principle:
Principle #25Self-service

4Duration of action of stationary object

If a hard coating is applied to the sliding surface, then wear resistance is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvewear resistanceVSAvoidcoating application precision
Core Design Contradiction:
Duration of action of stationary objectVSManufacturing precision

Solution Approach 1:

A hard coating (such as diamond-like carbon or ceramic) is applied to the sliding surface of the tilting segment to create a composite structure combining the mechanical strength of the base material with the wear resistance of the coating. This composite approach significantly extends service life under mixed-friction conditions while the coating process itself accommodates normal manufacturing tolerances.

Inventive Principle:
Principle #40Composite materials

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 solution effectively neutralizes axial forces, reduces wear, and maintains low frictional resistance, allowing for efficient operation under mixed-friction conditions, thereby enhancing the stability and longevity of the transmission system.

Implementation Method 1

a spring element arranged between the tilting segment and the planet carrier, by means of which elastic support is provided for the tilting segment, in particular in the axial direction

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a hard coating for low friction and wear resistance

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

a hard coating for low friction and wear resistance

Methodology Applied
Scientific EffectWear: Wear

Data Source

PatentEP3612743B1Transmission assembly comprising axial tilt segments
Publication Date: 2022.12.28 ZF FRIEDRICHSHAFEN AG
  • EP3612743B1 patent drawingFigure 1a~1b
  • EP3612743B1 patent drawingFigure 2
  • EP3612743B1 patent drawingFigure 3

AI summary

A transmission assembly comprising a planetary gear set (1), said planetary gear set (1) comprising a sun gear (2), planet gears (3) and a ring gear (4), the planet gears (3) each being rotatably mounted on a planet shaft (7) in each case by means of a bearing (5) and the planet shaft (7) being connected to a planet carrier (6), characterised in that tilt segments (8) arranged radially circumferentially with respect to the planet shaft are provided on the sides of the planet carrier (6) facing towards the planet gears (3), and in that the planet carrier (6), on its sides facing towards the planet gears (3), has recesses (9) arranged circumferentially radially with respect to the planet shaft and corresponding to the tilt segments (8), which recesses are intended to receive at least part of the tilt segments (8).