Composite Pedal Shaft Coupling for Dimensional Stability

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing coupling devices for motor vehicle pedals made solely of plastic materials face issues with hygroscopicity, leading to shape changes due to temperature and moisture, resulting in reduced accuracy and stress transmission efficiency.

Innovation Solution

A coupling device comprising a plastic body and a metal tube, where the metal tube supports mechanical stresses and the plastic body is designed with reduced mechanical requirements, avoiding hygroscopicity issues and achieving cost-effectiveness, while maintaining proper rotary movement and load transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If a shaft is made solely of plastic material to reduce weight and cost, then the coupling device becomes lighter and cheaper, but the shaft absorbs moisture at high temperatures causing shape changes, enlarged dimensions, reduced accuracy of rotary movement, and poor stress transmission

Engineering Contradiction:

Improveweight of coupling deviceVSAvoiddimensional stability of shaft

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

The shaft is constructed as a composite structure with a plastic body and a metal tube arranged substantially coaxially. The metal tube provides dimensional stability and resistance to moisture absorption, while the plastic body reduces weight and manufacturing cost. This composite approach resolves the contradiction by combining materials with complementary properties.

Inventive Principle:

Principle #40Composite materials

2Strength

If a shaft is made solely of plastic material to meet mechanical requirements, then the coupling device achieves adequate strength, but the shaft presents hygroscopicity problems causing shape changes and reduced accuracy

Engineering Contradiction:

Improvemechanical strength of shaftVSAvoidhygroscopicity of plastic shaft

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The shaft is divided into two functional segments: a plastic body that provides cost-effectiveness and adequate baseline strength, and a metal tube that resists hygroscopicity and maintains dimensional stability. This segmentation allows each material to perform its optimal function without suffering from the weaknesses of the other.

Inventive Principle:

Principle #1Segmentation

3Reliability

If a shaft is made solely of metal material to ensure high strength and dimensional stability, then the coupling device achieves high reliability, but the device becomes heavier and more expensive

Engineering Contradiction:

Improvedimensional stability of shaftVSAvoidweight of coupling device

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The metal tube is positioned locally within the shaft structure where it is most needed - providing dimensional stability and resistance to hygroscopicity - while the plastic body constitutes the majority of the shaft's volume, reducing overall weight and cost. This local application of metal material optimizes the weight-strength trade-off.

Inventive Principle:

Principle #3Local quality

Data Source

PatentEP2620832B1Coupling device for at least one motor vehicle pedal

Publication Date: 2022.05.18 BATZ SCOOP

Figure 1~2
Figure 3~4
Figure 5~6

AI summary

Device for coupling a pedal (3) of a motor vehicle to a support piece (2) that comprises a shaft (4) that passes through the pedal (3) and the support piece (2), fixing the pedal (3) to the support piece (2). The shaft (4) comprises a plastic body (6) and a metal tube (5) arranged substantially coaxially to the body (6) on the exterior of said body (6), the pedal (3) being arranged supported on the tube (5) and the tube (5) on the support piece (2).