Steering Column Gear Wheel With Injection-Molded Thread Insert

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Solution Overview

Problem

The existing gear wheels for motor-adjustable steering columns require high manufacturing and assembly effort due to the need for separate components and complex assembly processes, which can lead to reduced load-bearing capacity and durability.

Innovation Solution

A gear wheel design where a plastic threaded element is injection-molded onto a core element, forming a durable and dimensionally accurate internal thread, reducing manufacturing and assembly effort while enhancing load-bearing capacity and durability through a material and positive connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a separate threaded element is manufactured and assembled into the core element, then the gear wheel can be produced using conventional manufacturing methods, but the manufacturing and assembly effort increases and the load-bearing capacity decreases

Engineering Contradiction:

Improvemanufacturing effortVSAvoidload-bearing capacity

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The threaded element and core element are merged into a single integrated component through injection molding. The plastic threaded element is injected directly onto the metal core element, creating a permanent bond that eliminates separate assembly steps while maintaining manufacturing feasibility through the injection molding process.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The gear wheel utilizes a composite structure combining metal core element with plastic threaded element. This composite approach allows each material to contribute its advantageous properties - the metal provides structural strength and the plastic provides threading functionality - while being manufactured as an integrated unit through injection molding.

Inventive Principle:

Principle #40Composite materials

2Productivity

If a separate threaded element is assembled into the core element, then manufacturing flexibility is maintained, but the assembly process becomes complex and time-consuming

Engineering Contradiction:

Improveassembly speedVSAvoidassembly process complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The manufacturing process merges the production of the threaded element and core element into a single injection molding operation. This eliminates the need for separate manufacturing and assembly steps, reducing assembly complexity to zero while significantly increasing productivity through one-step manufacturing.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The threaded element is pre-formed during the injection molding process itself, before any assembly is required. The plastic material is injected onto the core element in its final threaded configuration, eliminating the need for subsequent threading or assembly operations.

Inventive Principle:

Principle #10Preliminary action

3Strength

If a threaded element is joined to the core element through material and positive connection, then the load-bearing capacity increases, but the manufacturing precision requirements increase

Engineering Contradiction:

Improveload-bearing capacityVSAvoiddimensional accuracy

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The composite structure of plastic threaded element on metal core element inherently provides both material connection (through adhesion) and positive connection (through geometric interlocking). The injection molding process creates a bond that distributes loads across the interface, maintaining high load-bearing capacity while the process itself ensures dimensional accuracy through mold-based formation.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The injection molding process allows control of material parameters (temperature, pressure, injection rate) to optimize the bonding between the plastic threaded element and metal core element. By adjusting these parameters, the process achieves both strong material connection and precise dimensional control without requiring post-assembly operations.

Inventive Principle:

Principle #35Parameter changes

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 reduces manufacturing and assembly effort while increasing the load-bearing capacity and durability of the gear wheel, ensuring efficient and safe operation, especially under high stress and crash conditions.

Implementation Method 1

the threaded element is formed from a plastic as an injection molded plastic part, which is molded onto the core element on an inner wall of the passage opening

Methodology Applied

Scientific EffectInjection molding:

Data Source

PatentUS11407437B2Gear wheel of an adjustment drive mechanism for a steering column and steering column for a motor vehicle

Publication Date: 2022.08.09 THYSSENKRUPP PRESTA AG

AI summary

A gear wheel for an adjustment drive mechanism which has a ring gear which is attached coaxially circumferentially to the outside of a core element which has an axial passage opening, in which a threaded element is fitted, the latter having an axially continuous internal thread having at least one thread tooth running around helically. The threaded element is formed from a plastic as an injection molded plastic part, which is molded onto the core element on an inner wall of the passage opening.