Universal Joint Stop Geometry for Bearing Failure Run-On

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Solution Overview

Problem

Existing cardan joints are prone to bearing failure, leading to increased rotational diameter and potential damage to surrounding components due to excessive displacement, inefficient use of installation space, and risk of further damage.

Innovation Solution

A cardan joint design with projections on the pivot cross and joint forks that limit displacement during bearing failure, featuring stop surfaces and recesses to prevent excessive movement and reduce friction, maintaining normal operation characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a universal joint is designed for standard operation, then it achieves normal rotational transmission, but it cannot be operated in emergency situations where the drive shaft rotation is stopped or reversed

Engineering Contradiction:
Improveemergency operation capabilityVSAvoidoperational reliability in emergency
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The spring element is pre-loaded during normal operation to store energy. When emergency operation is needed (drive shaft stopped or reversed), the pre-loaded spring automatically provides the force needed to rotate the drive shaft in the same direction, enabling emergency operation without additional components or complex mechanisms.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The universal joint uses its own operational energy (rotation during normal use) to pre-load the spring element. The spring then serves the dual purpose of maintaining normal operation and enabling emergency operation when the drive shaft is stopped or reversed, making the system self-sufficient for both standard and emergency conditions.

Inventive Principle:
Principle #25Self-service

2Ease of operation

If the universal joint allows rotation in both directions, then it provides operational flexibility, but it cannot transmit torque effectively when the drive shaft is stopped or reversed

Engineering Contradiction:
Improverotational flexibilityVSAvoidtorque transmission capability
Core Design Contradiction:
Ease of operationVSPower

Solution Approach 1:

The spring element is pre-loaded during normal unidirectional rotation to store energy. When the drive shaft needs to rotate in reverse or be stopped, the pre-loaded spring automatically acts to maintain rotation in the original direction, ensuring continuous torque transmission capability while allowing operational flexibility.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If a complex mechanism is added to enable emergency operation, then emergency capability is improved, but the device complexity increases

Engineering Contradiction:
Improveemergency operation capabilityVSAvoidstructural complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The spring element is integrated directly into the existing universal joint structure, combining the emergency operation mechanism with the standard universal joint components. This merging approach enables emergency capability without adding separate complex systems, maintaining simplicity while expanding functionality.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The spring element serves multiple functions: it maintains torque transmission during normal operation, enables emergency operation when the drive shaft is stopped, and provides the force needed for reverse rotation. This multi-functionality eliminates the need for separate emergency mechanisms, reducing overall device complexity.

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

Enhances emergency running properties by minimizing space requirements and reducing the risk of damage to surrounding components, ensuring smooth operation and reduced friction during bearing failure.

Implementation Method 1

a spring element (20) arranged to be pre-loaded during a normal operation of the universal joint (1) and to serve as a drive shaft (10) rotation element

Methodology Applied
Scientific EffectElastic energy storage: Elasticity

Data Source

PatentEP4505090B1Universal joint with emergency running properties as well as articulated shaft and automotive vehicle with the universal joint
Publication Date: 2026.04.29 BAYERISCHE MOTOREN WERKE AG
  • EP4505090B1 patent drawingFigure 1~2
  • EP4505090B1 patent drawingFigure 3~5

AI summary

The invention relates to a universal joint (13) and a corresponding joint shaft (12), as well as to a motor vehicle provided with same. The universal joint (13) comprises two joint forks (14) and a cross pin (6) with a central body (2) and four pins (3) projecting from same. Next to at least one of the pins (3), at least one formation (7, 16) is formed which, perpendicular to the central longitudinal axis (10) of the respective pin (3), projects beyond same and which has a stop surface lying perpendicular to the common plane. This stop surface functions, only in the event of failure of a bearing of the respective pin (3), as a stop for supporting the cross pin (6) on an inner side of the corresponding joint fork (14) facing said cross pin in order to limit a shifting of the cross pin (6) relative to the corresponding joint fork (14) along the central longitudinal axis (10) of the respective pin (3).