Universal Joint Bearing Seal Layout for Compact High-Load Capacity

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Solution Overview

Problem

Existing universal joint bearings face challenges in achieving a compact construction with effective sealing and high dynamic carrying capacity, while also being able to withstand significant forces and torques.

Innovation Solution

The universal joint bearing is designed with specific axial length ratios of rolling elements, seals, and structural components to ensure a compact and efficient design, incorporating a robust seal with metallic parts and elastomeric elements to enhance sealing and dynamic capacity, along with a cruciform component for high force resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the universal joint bearing is designed with a compact construction, then the axial length is reduced, but the sealing effect and dynamic carrying capacity may be compromised

Engineering Contradiction:

Improveaxial lengthVSAvoidsealing effect and dynamic carrying capacity

Core Design Contradiction:

Length of moving objectVSReliability

Solution Approach 1:

The patent applies parameter changes by optimizing the ratio between the sum of maximum axial lengths of rolling element rows and the sum of maximum axial lengths of the cylindrical surface and seal radially outer surface to be between 0.6 and 0.75. This specific parameter range enables compact axial construction while maintaining adequate sealing and load-bearing capabilities.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The seal design extends in the radial direction with arms that reach toward the rolling elements, creating a multi-dimensional sealing approach. The seal has a radially outer surface with arms extending radially inward, allowing effective sealing without increasing axial length, thus resolving the contradiction between compactness and sealing effectiveness.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If the seal is designed to contact the trunnion directly, then sealing effectiveness is improved, but the axial construction becomes less compact

Engineering Contradiction:

Improvesealing effectivenessVSAvoidaxial length

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The patent introduces an intermediary structure where the seal's radially outer surface with arms acts as a mediator between the seal and the rolling elements/trunnion system. The sealing lip contacts the radially outer surface of the second arm rather than the trunnion directly, achieving effective sealing while maintaining compact axial construction through this intermediate contact surface.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Strength

If multiple cylindrical surfaces are added to the cup, then structural support is improved, but the radial outer surface complexity increases

Engineering Contradiction:

Improvestructural supportVSAvoidradial outer surface complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent extracts unnecessary cylindrical surfaces from the cup design. It explicitly states that adjacent to the substantially cylindrical surface, there is no further substantially cylindrical surface of the cup located that is part of the radially outer surface. This simplification maintains structural support while reducing radial outer surface complexity.

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

This design achieves a compact, efficiently sealed universal joint bearing with high dynamic carrying capacity and the ability to withstand high forces and torques, reducing wear and assembly complexity.

Implementation Method 1

rolling elements which rotatably support the cup relative to the trunnion

Methodology Applied

Scientific EffectRolling: Roller

Implementation Method 2

at least one seal which seals a space between the trunnion and the cup

Methodology Applied

Scientific EffectSealing:

Implementation Method 3

a sealing lip of the seal abuts against a radially outer surface of the second arm

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 4

the first row of rolling elements comprises at least one rolling element with a running surface, which has contact with the trunnion along its complete axial extension

Methodology Applied

Scientific EffectContact stress:

Data Source

PatentUS20250243910A1Universal joint bearing and universal joint cross

Publication Date: 2025.07.31 AB SKF SKF PATENT DEPARTMENT

AI summary

A universal joint bearing includes a trunnion, a cup, rolling elements rotatably supporting the cup relative to the trunnion, and at least one seal for sealing a space between the trunnion and the cup. The cup has a substantially cylindrical surface, which is a part of a radially outer surface of the universal joint bearing. All of the rolling elements of the universal joint bearing are arranged in a certain number of rows of rolling elements. A sum of the maximum axial lengths of all the rows of rolling element divided by the sum of the maximum axial length of the substantially cylindrical surface and the maximum axial length of a radially outer surface of the at least one seal, which is another part of the radially outer surface of the universal joint bearing, is between 0.6 and 0.75.