Integral Cam-Tie Rod Steering Column Locking Device

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Solution Overview

Problem

Existing locking devices for adjustable motor vehicle steering columns are complex to assemble and can produce parasitic noises due to movable components.

Innovation Solution

A locking device with a cam integral to the tie rod, featuring an actuating lever made of plastic overmoulded on the tie rod, eliminating the need for stacking during assembly and reducing component movement, thus simplifying assembly and minimizing noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the cam and tie rod are made as separate stacked components, then the locking device can be assembled with standard fastening methods, but the assembly process becomes complex and produces parasitic noises during operation

Engineering Contradiction:
Improveease of assemblyVSAvoidstructure complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent merges the cam and tie rod into a single integral component. The cam is directly formed on the tie rod, eliminating the need for separate stacking of washers and fastening nuts. This integration simplifies the assembly process and reduces the number of parts, directly resolving the technical contradiction between ease of manufacture and device complexity.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If the cam and tie rod are stacked with multiple components, then the locking device can be assembled using standard fastening methods, but parasitic noises occur due to relative movement between components during use

Engineering Contradiction:
Improvenoise reductionVSAvoidease of assembly
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

By integrating the cam and tie rod into one piece, the patent eliminates relative movement between these components during operation. This merger prevents the parasitic noises that would otherwise occur from friction and movement between stacked components, while also simplifying the assembly process by reducing the number of parts to be fastened together.

Inventive Principle:
Principle #5Merging (Combining)

3Productivity

If multiple stacked components are used for the cam and tie rod, then the locking device can be assembled with standard fastening methods, but the assembly time and production cost increase

Engineering Contradiction:
Improveassembly efficiencyVSAvoidnumber of components
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The integration of cam and tie rod into a single component reduces the total number of parts that need to be assembled. This merger eliminates the stacking step and associated fastening operations, directly improving assembly efficiency and productivity while reducing the complexity of the device structure.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent segments the locking device into distinct functional modules: the integral cam-tie rod assembly, the actuating lever mechanism, and the flange structure. This functional segmentation allows for optimized manufacturing of each module while simplifying the overall assembly process, thereby improving productivity without compromising functionality.

Inventive Principle:
Principle #1Segmentation

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 solution simplifies assembly, reduces parasitic noise, and is cost-effective by integrating the cam and tie rod into a one-piece member, ensuring secure locking and easy operation.

Implementation Method 1

an actuating lever, operable by rotation around the axis of the tie rod), made of plastic overmoulded on the tie rod

Methodology Applied
Scientific EffectOvermoulding:

Data Source

PatentEP2322406B1Simplified device for locking in position an adjustable steering column of a vehicle
Publication Date: 2013.06.26 FUJI AUTOTECH FRANCE SAS
  • EP2322406B1 patent drawingFigure 1
  • EP2322406B1 patent drawingFigure 2
  • EP2322406B1 patent drawingFigure 3

AI summary

The device has an actuating lever made of a plastic material, and a tie rod (24) received in slots formed in flanges to adjust position of a height adjustable steering column by displacement of the tie rod in the slots. A tightening unit has a complementary support surface carried by one of the flanges so that a mobile cam (32) and the support surface are movable with respect to each other between an axially spaced position to lock the steering column by tightening of the flanges and an axially close-up position to release the steering column. The cam and the tie rod are made of same material.