Pivoting Variator Spring Tensioning

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Solution Overview

Problem

Existing swivel variators used in combine harvesters have complex structures that require support and guidance for adjusting disk and pulleys, leading to increased complexity and potential belt tension issues due to incorrect preload settings and belt elongation.

Innovation Solution

A simplified swivel variator design featuring a first frame section that rotates about a pivot axis and a second frame section prestressed by integrated spring elements, with linear guidance and coaxial hollow-cylindrical sections for belt pulleys and adjusting disk, reducing complexity and allowing for compact design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional pivoting variator with toggle lever arrangement is used to maintain belt tension, then the belt tension can be compensated for belt elongation, but the construction becomes complex requiring support and guidance of adjusting disk and pulleys

Engineering Contradiction:
Improvebelt tension maintenanceVSAvoidconstruction complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the frame structure with the tensioning function by integrating spring elements directly into the frame sections. The first and second frame sections are merged with the pulley support structure, eliminating the need for separate toggle lever arrangements and support mechanisms. This integration maintains belt tension compensation while simplifying the overall construction.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The frame sections serve multiple functions: they support the pulleys, guide the adjusting disk, and provide the spring-based tensioning mechanism. The first frame section rotates about a pivot axis while the second frame section moves linearly, creating a multi-functional structure that replaces several separate components in traditional designs.

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

2Power

If the pretension is set too high to prevent slippage, then power transmission is maintained, but the service life of the belt is significantly reduced

Engineering Contradiction:
Improvepower transmissionVSAvoidbelt service life
Core Design Contradiction:
PowerVSDuration of action of stationary object

Solution Approach 1:

The spring-based tensioning mechanism dynamically adjusts the belt pretension parameter based on operating conditions and belt elongation. Instead of using a fixed high pretension setting, the system maintains an optimal pretension level that prevents slippage while avoiding excessive stress on the belt, thereby extending its service life.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The spring elements automatically adjust the belt tension as the belt elongates during operation. The system self-regulates the pretension force without requiring external intervention or overly aggressive initial settings, maintaining sufficient power transmission while protecting the belt from excessive stress.

Inventive Principle:
Principle #25Self-service

3Duration of action of stationary object

If the pretension is set too low to extend belt service life, then belt stress is reduced, but power transmission is compromised

Engineering Contradiction:
Improvebelt service lifeVSAvoidpower transmission
Core Design Contradiction:
Duration of action of stationary objectVSPower

Solution Approach 1:

The tensioning system transitions from a static fixed pretension setting to a dynamic adjustment mechanism. The spring elements continuously adapt the belt tension based on the actual operating conditions and belt elongation, ensuring sufficient power transmission at all times while avoiding excessive pretension that would reduce belt service life.

Inventive Principle:
Principle #15Dynamics

4Reliability

If a complex toggle lever arrangement is used for tensioning, then belt tension compensation is achieved, but the device size and space requirements increase

Engineering Contradiction:
Improvebelt tension compensationVSAvoiddevice volume
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent merges the tensioning mechanism within the existing frame structure by integrating spring elements into the first and second frame sections. This eliminates the need for separate toggle lever arrangements and extends the functional capacity of the frame itself, achieving tension compensation without increasing device volume.

Inventive Principle:
Principle #5Merging (Combining)

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 easier handling and adjustment of belt pretension, reduces excessive belt tension drop, and maintains power transmission efficiency during load changes, enhancing the service life and operational reliability of the belts.

Implementation Method 1

a second frame section (17), which is prestressed relative to the first frame section (15) by means of at least one spring element (16) integrated into the frame (13)

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

The hollow-cylindrical section of the bearing bracket, which extends in sections in the longitudinal direction of the carrier, encloses the carrier at least in sections in the radial direction. This ensures sliding guidance of the fixed belt pulleys

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2993377B1Pivoting variator
Publication Date: 2017.05.10 CLAAS SELBSTFAHRENDE ERNTEMASCHINEN GMBH
  • EP2993377B1 patent drawingFigure 1
  • EP2993377B1 patent drawingFigure 2
  • EP2993377B1 patent drawingFigure 3

AI summary

The present invention relates to a swivel variator (4) with a pivotable frame (13) and fixed pulleys (9, 10) guided by it, between which an axially displaceable adjusting disc (14) is arranged, wherein the frame (13) has a first frame section (15) which is rotatable about a pivot axis (8), and a second frame section (17) which is pre-tensioned relative to the first frame section (15) by means of at least one spring element (16a, 16b) integrated into the frame (13), on which the pulleys (9, 10) and the adjusting disc (14) are mounted, wherein the second frame section (17) is guided linearly by means of the first frame section (15).