Rack Guide Frictional Holding for Steering Assembly

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Solution Overview

Problem

The existing rack guide devices require complex and time-consuming assembly processes due to the need for snap rings in holding disc springs and interposed members, leading to increased assembly time and reduced performance.

Innovation Solution

The holding member is integrated with the blocking member through frictional engagement, allowing for a simpler assembly process and improved performance by absorbing dimensional errors and distributing loads effectively, while also reducing the device's size and integrating disc springs and compression coil springs for enhanced load management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If snap rings are used to hold the disc spring and interposed member in the cylindrical portion, then the disc spring and interposed member can be secured in place, but the assembly process becomes complex and time-consuming

Engineering Contradiction:
Improvesecuring of disc spring and interposed memberVSAvoidassembly time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The snap ring is extracted from the assembly structure and replaced with a frictional engagement mechanism between the holding member and blocking member, eliminating the need for separate securing components and reducing assembly complexity

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The holding member is merged with the blocking member through frictional engagement, combining multiple functions into a single integrated assembly operation that secures both the disc spring and interposed member without requiring separate fastening steps

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If snap rings and circumferential grooves are used to hold components, then the components can be retained, but the number of assembly steps and man-hours increases

Engineering Contradiction:
Improvecomponent retentionVSAvoidassembling performance
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The holding member utilizes frictional engagement with the blocking member to automatically secure itself and the disc spring assembly without requiring additional fastening operations or specialized assembly tools, thereby improving productivity

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The frictional engagement mechanism serves multiple functions simultaneously: it secures the holding member to the blocking member, retains the disc spring, and positions the interposed member, replacing multiple separate fastening operations with a single universal assembly action

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

This approach significantly improves the assembly efficiency and performance of the rack guide device by simplifying the assembly process, ensuring accurate integration, and providing a two-stage load characteristic for better load management and wear resistance.

Implementation Method 1

an elastic member 23 that is held on the holding member 24 so as to be in frictional engagement with the blocking member 20

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

an elastic member 23 that is held on the holding member 24 so as to be in frictional engagement with the blocking member 20

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2982569B1Rack guide device and steering apparatus including same
Publication Date: 2019.06.19 JTEKT CORP
  • EP2982569B1 patent drawingFigure 1
  • EP2982569B1 patent drawingFigure 2
  • EP2982569B1 patent drawingFigure 3

AI summary

A rack guide device includes a rack guide, a blocking member, at least one plate spring, and a holding member. The rack guide is accommodated in an accommodating portion that is formed in a housing through which a rack shaft configured to mesh with a pinion shaft is inserted so as to move towards or away from the rack shaft and that supports the rack shaft so as to allow the rack shaft to slide in an axial direction thereof. The blocking member is fixed to an external opening end that is provided on an opposite side of the accommodating portion to a side thereof that faces the rack shaft. The disc spring is interposed between the blocking member and the rack guide to bias the rack guide towards the rack shaft. The holding member holds the disc spring and is directly or indirectly held to the blocking member through frictional engagement.