Friction Drive Torque Limiting Roller Bearing

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Solution Overview

Problem

Friction drives for power transmission in transport conveyor devices face challenges with wear and limited adjustability of transmission torque, leading to inefficiencies and potential damage from excessive torque.

Innovation Solution

A friction drive system utilizing a torque limiting device with a roller bearing and clamping mechanism that allows adjustable transmission torque by axial displacement of the inner ring relative to the outer ring, featuring a rotary decoupling device and a tensioning system with spring elements for metered force application, ensuring almost wear-free operation and freewheeling when excessive torque is applied.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a friction drive is used to transmit drive torque from drive element to driven element, then power transmission is achieved, but wear occurs between the friction surfaces

Engineering Contradiction:
Improvedrive torque transmissionVSAvoidwear resistance
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

A roller bearing is introduced as an intermediary element between the drive element and driven element. The roller bearing includes an inner ring, outer ring, and rolling elements that transmit torque through rolling contact rather than sliding friction, significantly reducing wear while maintaining power transmission capability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The traditional sliding friction interface is replaced with a rolling bearing mechanism. The rolling elements between the inner and outer rings convert sliding friction into rolling friction, eliminating the wear problem associated with direct friction drives

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If a torque limiting device is added to prevent excessive torque damage, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improveprotection from excessive torqueVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The torque limiting function is merged into the roller bearing assembly itself. By applying an axial clamping force to the roller bearing, the torque limit is adjusted through the preloading of the rolling elements, eliminating the need for a separate torque limiting device and reducing overall structural complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The roller bearing serves multiple functions: it transmits torque with reduced wear, limits maximum torque through controlled slippage when the torque exceeds the preloaded value, and provides axial positioning. This multi-functionality reduces the need for additional components

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

3Adaptability or versatility

If a clamping device is used to adjust transmission torque by displacing inner ring axially, then adaptability is improved, but friction in the roller bearing increases due to additional forces

Engineering Contradiction:
Improvetransmission torque adjustabilityVSAvoidfriction loss
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The clamping device is designed to apply axial force that is segmented and distributed through the roller bearing's rolling elements. This segmentation allows the axial displacement to be converted into controlled preloading of the rolling elements rather than creating additional sliding friction

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The use of curved rolling elements (balls or rollers) in the bearing allows the axial clamping force to be converted into radial preloading through geometric transformation. The spherical or cylindrical geometry of the rolling elements enables force transformation that minimizes additional friction while achieving the desired torque adjustment

Inventive Principle:
Principle #14Spheroidality (Curvature)

4Ease of operation

If sealing elements are arranged in an annular gap to improve axial displaceability, then ease of operation is improved, but device complexity increases

Engineering Contradiction:
Improveaxial displaceabilityVSAvoidsealing structure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The sealing function is extracted as a separate component arranged in the annular gap between the inner ring and shaft section. This extraction allows the sealing elements to be independently optimized for axial displaceability without complicating the main bearing structure, as they can be installed and replaced separately

Inventive Principle:
Principle #2Taking out (Extraction)

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 system achieves defined and adjustable drive torque transmission with reduced wear, allowing for efficient power transfer while preventing damage from excessive torque through freewheeling, and can be easily integrated into transport conveyor devices with minimal space requirements.

Implementation Method 1

at least one roller bearing with an inner ring and an outer ring as well as roller bodies arranged between them

Methodology Applied
Scientific EffectRolling friction: Friction

Implementation Method 2

a clamping device for axially displacing the inner ring to the outer ring of the at least one roller bearing against one another

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

The tensioning device acting on the torque-limiting device preferably comprises at least one spring element

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2920090B1Friction drive for force transmission, in particular for a transport conveying device
Publication Date: 2016.10.05 KIENER MASCHENBAU GMBH
  • EP2920090B1 patent drawingFigure 1
  • EP2920090B1 patent drawingFigure 2
  • EP2920090B1 patent drawingFigure 3

AI summary

The invention relates to a friction drive for force transmission, in particular for a transport conveying device, comprising a drive element (31) and an output element (34) and comprising a torque-limiting device (33), which acts therebetween and transmits a drive torque introduced by said drive element (31) up to a transmission torque, which can be set by means of the torque-limiting device (33), to the output element (34), and allows free running when a drive torque exceeds the set transmission torque, and which comprises at least one rolling bearing (41) having an inner race (42) and an outer race (46) and rolling bodies (45) arranged therebetween, and a clamping device (51), by means of which the inner race and the outer race of the at least one rolling bearing (41) of the torque-limiting device (33) can be displaced towards each other in an axial direction or can be clamped against each other in a radial direction and a transmission torque can be set.