Trailer Shunting Drive Roller Axis Alignment Compensation

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Solution Overview

Problem

Existing shunting drives for trailers face challenges in maintaining a parallel position of the drive roller axis and trailer wheel axis due to tolerances and elasticity, leading to increased slip and tire wear, as the drive roller often becomes angled when pressed against the wheel, compromising power transmission.

Innovation Solution

The shunting drive design includes a carrier with a drive roller that moves between rest and drive positions, where the axis of rotation is initially angled to compensate for tolerances and elasticity, ensuring it becomes parallel to the wheel axis upon contact, using a cantilevered mounting and elastic deformation to maintain optimal contact pressure and minimize slippage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the drive roller is pressed against the trailer wheel to achieve optimal traction, then power transmission is improved, but the drive roller axis becomes angled relative to the wheel axis due to tolerances and elasticity, causing increased slip and tire wear

Engineering Contradiction:
Improvepower transmissionVSAvoidalignment precision
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The drive roller is pre-positioned at an angled orientation (e.g., 5-15 degrees) relative to the wheel axis before engagement. This preliminary angular adjustment compensates for the expected elastic deformation and tolerance accumulation that occurs when the drive roller is pressed against the wheel during operation, ensuring that the axes become parallel under load conditions.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the angular parameter of the drive roller axis from a parallel position (0 degrees) in the unloaded state to a pre-calculated angled position (5-15 degrees) in the loaded state. This parameter adjustment accounts for the elastic deformation of the carrier and fastening device under contact pressure, maintaining optimal alignment between the drive roller axis and wheel axis during power transmission.

Inventive Principle:
Principle #35Parameter changes

2Weight of moving object

If the cross member wall thickness is reduced to save weight, then the overall weight of the shunting drive is decreased, but the rigidity of the cross member is limited, allowing elastic deformation under load

Engineering Contradiction:
Improveshunting drive weightVSAvoidcross member rigidity
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The system pre-compensates for the elastic deformation of the cross member by angling the drive roller axis in advance. Instead of designing the cross member with excessive thickness to prevent deformation, the invention accepts the deformation as predictable and compensates for it through the angular adjustment, allowing weight reduction while maintaining alignment precision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention transforms the rigid structural requirement (thick cross member) into a configurable angular parameter (drive roller orientation). By changing the angular parameter based on expected deformation, the system achieves the same alignment precision with a lighter, more flexible cross member structure.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If guides with tight tolerances are used to maintain drive roller alignment, then alignment precision is improved, but the complexity and manufacturing cost of the shunting drive increases

Engineering Contradiction:
Improvedrive roller alignmentVSAvoidguide structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Instead of relying on tight-tolerance guides to maintain alignment during operation, the invention pre-positions the drive roller at an angled orientation that anticipates the alignment shift. This eliminates the need for complex, high-precision guide structures, as the alignment compensation is built into the initial angular setting rather than requiring precision maintenance during movement.

Inventive Principle:
Principle #10Preliminary action

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 design ensures optimal traction and reduced tire wear by maintaining a parallel drive roller axis to the wheel axis, preventing undesired tilting and enhancing power transmission, while also allowing for material savings and weight reduction in the shunting drive system.

Implementation Method 1

the angular position of the axis of rotation of the drive roller when the drive position is reached while the drive roller is being pressed against the wheel of the trailer can be changed due to elasticity and/or tolerances

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2669154B1Trailer manoeuvring drive
Publication Date: 2016.08.24 TRUMA GERATETECHNIK GMBH & CO KG
  • EP2669154B1 patent drawingFigure 1
  • EP2669154B1 patent drawingFigure 2
  • EP2669154B1 patent drawingFigure 3

AI summary

The invention relates to a shunting drive for a trailer, comprising a fastening device (5) for attachment to the trailer, a support (7) movable relative to the fastening device (5), a drive motor (1) held by the support (7), and a drive roller (2) rotatably driven by the drive motor (1) and held by the support (7). The support (7) is movable back and forth between a rest position in which the drive roller (2) is separated from a wheel (8) of the trailer and a drive position in which the drive roller (2) is pressed against the wheel (8) of the trailer.In the rest position, the drive roller pivot axis (2a) of the drive roller (2) is at an angle other than 0 degrees to the wheel pivot axis (8a) of the wheel (8). The angular position of the drive roller pivot axis (2a) can change when the drive position is reached during the pressing action of the drive roller (2) against the wheel (8) of the trailer due to elasticities and/or tolerances. The angle of the drive roller pivot axis (2a) in the rest position is selected such that, in the drive position, after the pressure action against the wheel (8) has been completed and the elasticities and tolerances have been compensated for, the drive roller pivot axis (2a) is parallel to the wheel pivot axis (8a).