Steering Spindle Sliding Sleeve with Pre-Toothing

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Solution Overview

Problem

Existing steering spindle arrangements face challenges in maintaining the rotational angle position of the steering spindle when axially displaced, due to limited sliding path caused by the absence of internal toothing at one end of the sliding sleeve, which restricts the spindle's retraction during engine assembly and hinders its mounting on the steering gear.

Innovation Solution

A sliding sleeve blank with a cylindrical shape, featuring a circumferential collar and radially extending wing webs, is cold-extruded to include internal teeth over part of its length, allowing for additional hammered teeth during processing, resulting in a sliding sleeve with almost continuous internal teeth for an extended guided path, and a pre-toothing section to maintain the rotational angle position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the steering spindle is pulled back during engine assembly, then collision with the motor is avoided, but the rotational angle position cannot be maintained due to missing internal toothing at one end of the sliding sleeve

Engineering Contradiction:

Improveretraction distance of steering spindleVSAvoidmaintenance of rotational angle position

Core Design Contradiction:

Length of moving objectVSReliability

Solution Approach 1:

The sliding sleeve's internal toothing is divided into two distinct sections: a first section with internal toothing for normal operation, and a second section (collar region) without internal toothing for engine assembly retraction. This segmentation allows the steering spindle to be pulled back during assembly while maintaining rotational angle position during normal operation, resolving the contradiction between retraction distance and position maintenance.

Inventive Principle:

Principle #1Segmentation

2Reliability

If internal toothing is provided over the entire length of the sliding sleeve, then rotational angle position is maintained, but the steering spindle cannot be pulled back far enough during engine assembly

Engineering Contradiction:

Improvemaintenance of rotational angle positionVSAvoidretraction distance of steering spindle

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The sliding sleeve exhibits local quality variation through its length: the first section has internal toothing for maintaining rotational angle position, while the second collar section has no internal toothing to enable maximum retraction during engine assembly. This localized differentiation resolves the contradiction by providing the necessary retraction distance in the collar region while preserving position maintenance in the toothed section.

Inventive Principle:

Principle #3Local quality

3Manufacturing precision

If hammering is used to create internal toothing, then highly precise configuration is achieved, but the collar region cannot be processed due to presence of wings and collar structure

Engineering Contradiction:

Improveprecision of internal toothingVSAvoidprocessability of collar region

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The manufacturing process is segmented into two parts: the first section with internal toothing is produced using precise hammering, while the second collar section is formed separately without hammering. This segmentation resolves the contradiction by applying the precise hammering process only where needed, while accepting a different formation method for the collar region that prevents hammering access.

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 provides a structurally simple and cost-effective steering spindle arrangement that ensures the steering spindle maintains its rotational angle position during axial displacement, enabling uninterrupted guidance and tolerance compensation, thus facilitating unhindered assembly and operation.

Implementation Method 1

The sliding sleeve blank (1') is a cold-extruded component which has received internal teeth (3) directly during production

Methodology Applied

Scientific EffectCold extrusion: Cold-forming

Implementation Method 2

the sleeve is radially machined from the outside with hammers, the inner contour of the sleeve adopting the toothed contour of the mandrel

Methodology Applied

Scientific EffectImpact force: Impact Force

Data Source

PatentEP2640622B1Sliding sleeve blank and motor vehicle steering spindle assembly having a sliding sleeve made from the blank

Publication Date: 2017.02.15 MERCEDES BENZ GROUP AG

AI summary

The invention provides a sliding sleeve blank (1') for making a sliding sleeve (1) for a steering spindle shaft (10) of a motor vehicle steering spindle and the motor vehicle steering spindle assembly itself. The sliding sleeve blank (1') has a cylindrical shape and, at one end, has a section (6) which has a collar (4), from which winged webs (5) extending away radially extend in the direction of the end. The sliding sleeve blank (1') is a cold flow pressed component which, on the section (6), has a preliminary toothing system (3) extending over part of the length of the section (6).