Tripod Joint Drive Portion With Central Protrusions Against Roller Tilting

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Solution Overview

Problem

The existing tripod joint drive parts experience roller tilting during rotation, which can slow down or prevent the translation of the internal element, and previous solutions like reducing reception zone depth increase friction, leading to higher reaction times.

Innovation Solution

The drive part features central sub-parts with protrusions that extend axially, allowing rollers to rest on a single central support, preventing tilting and reducing friction by guiding them on a central protuberance, which can be radiated or semi-spherical in shape, and are either integral to the wall or attached via screwing, welding, or gluing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the depth of each reception zone is reduced so that the roller rests on two opposite lateral sub-parts, then the roller does not tilt, but friction increases significantly which slows down the translation of the internal element

Engineering Contradiction:
Improveroller stabilityVSAvoidtranslation speed
Core Design Contradiction:
Stability of the object's compositionVSProductivity

Solution Approach 1:

The reception zone is segmented into three distinct support areas: two lateral sub-parts and one central protuberance. The roller simultaneously contacts all three areas, with the central protuberance providing primary axial support to prevent tilting, while the lateral sub-parts provide additional stability. This segmentation allows the roller to remain stable without requiring reduced reception zone depth that would increase friction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The central protuberance acts as an intermediary element between the roller and the reception zone floor. It provides a dedicated axial support surface that prevents roller tilting without requiring the roller to rest on lateral sub-parts, thereby maintaining low friction conditions while ensuring roller stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the roller rests on a single central support, then friction is reduced and translation speed increases, but the roller may tilt during rotation of the drive part

Engineering Contradiction:
Improvetranslation speedVSAvoidroller stability
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The support structure is segmented into three distinct areas: a central protuberance for axial support and two lateral sub-parts for stability. This segmentation allows the roller to contact multiple support points simultaneously, preventing tilting while maintaining low friction through the central protuberance design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the reception zone are given different functions: the central protuberance provides axial support with low friction characteristics, while the lateral sub-parts provide additional stability. This local differentiation of qualities allows the system to achieve both low friction and roller stability simultaneously.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3861223B1Drive portion of a tripod joint with inner central Anti-tilting protrusions
Publication Date: 2022.12.14 PSA AUTOMOBILES SA
  • EP3861223B1 patent drawingFigure 1~2

AI summary

A drive portion (PE) forms part of a tripod joint (JT) comprising an inner element provided with three journals distributed at 120° from one another in the same plane, perpendicular to an axial direction, and each having one end provided with a roller (G). Said drive portion (PE) comprises an inner face (FI) defining an open housing (LO) provided at the periphery of three receiving areas (ZA) which are distributed at 120° from one another and each intended to accommodate one of the rollers (G) in translation in the axial direction. Each portion of the inner face (FI) defining a receiving area (ZA) comprises a central sub-portion defining a protrusion (PC) which extends in the axial direction and on which the associated roller (G) rests so that the latter (G) remains in the receiving area (ZA) upon rotation of the drive portion (PE).