Split Gear Axial Space Reduction via Spring Tongue Interlock

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Solution Overview

Problem

Existing split gear designs for camshafts and balancer shafts require significant installation space and have a detachable connection, which can weaken the collar's strength due to the need for a groove and additional material for support, and do not provide a permanent connection between gear halves.

Innovation Solution

A split gear design with two gear wheel halves connected via an annular disc with spring tongues that penetrate the material of a central component, forming a non-detachable, space-efficient connection without the need for a groove, using hardened metal edges for secure support.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a snap ring is used to detachably secure the second gear wheel half on the collar, then the connection can be easily assembled and disassembled, but a large amount of installation space is required in the axial direction and the collar strength is weakened due to the groove

Engineering Contradiction:
ImproveassemblabilityVSAvoidaxial installation space
Core Design Contradiction:
Ease of operationVSLength of stationary object

Solution Approach 1:

The invention removes the groove from the collar design, extracting the problematic feature that caused both the space issue and strength reduction. Instead of using a groove to accommodate a snap ring, the patent uses a protrusion on the collar that fits into a corresponding recess in the second gear wheel half, eliminating the need for material removal and additional axial space.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of creating a groove (negative space) in the collar to hold the snap ring, the invention inverts the approach by adding a protrusion (positive space) on the collar that fits into a recess in the gear wheel half. This inversion eliminates the need for the groove and reduces the axial space requirement while maintaining the detachable connection functionality.

Inventive Principle:
Principle #13The other way round (Inversion)

2Strength

If additional material 'meat' is provided at the free end of the collar to compensate for the groove weakening, then the collar strength is sufficient, but the axial installation space increases

Engineering Contradiction:
Improvecollar strengthVSAvoidaxial installation space
Core Design Contradiction:
StrengthVSLength of stationary object

Solution Approach 1:

The invention extracts the groove from the collar design, eliminating the source of strength reduction. By removing the groove that required compensating 'meat' material, the collar maintains its full strength without needing additional axial length, thus resolving both the strength and space issues simultaneously.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of removing material to create a groove and then adding compensating material, the invention inverts the approach by adding a protrusion that fits into a recess in the gear wheel half. This eliminates the need for both the groove and the compensating material, maintaining collar strength while reducing axial space.

Inventive Principle:
Principle #13The other way round (Inversion)

3Force

If a groove is made in the collar to support the snap ring, then axial forces can be absorbed, but the collar strength is weakened due to the notch effect

Engineering Contradiction:
Improveaxial force absorptionVSAvoidcollar strength
Core Design Contradiction:
ForceVSStrength

Solution Approach 1:

The invention extracts the groove from the collar design, eliminating the notch effect that weakened the collar. The axial force absorption function is maintained through the protrusion-recess interface between the collar and the second gear wheel half, which provides a strong mechanical interlock without compromising collar integrity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of creating a groove (negative space) that weakens the collar, the invention inverts the approach by adding a protrusion (positive space) on the collar that fits into a recess in the gear wheel half. This inverted design maintains axial force absorption capability while preserving collar strength by avoiding material removal.

Inventive Principle:
Principle #13The other way round (Inversion)

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 design minimizes axial installation space, ensures a permanent connection between gear halves, and enhances the strength of the collar by eliminating the need for a groove, allowing for a more compact and robust assembly.

Implementation Method 1

a spring element (14) arranged between the two gear wheel halves (2, 3), which braces the two gear wheel halves (2, 3) against one another when mounted

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2334941B1Divided toothed wheel
Publication Date: 2012.11.14 THYSSENKRUPP PRESTA TECCENTER AG
  • EP2334941B1 patent drawingFigure 1
  • EP2334941B1 patent drawingFigure 2
  • EP2334941B1 patent drawingFigure 3

AI summary

The invention relates to a divided toothed wheel (1) having two toothed wheel halves (2, 3) which are tensioned in relation to each other. The first toothed wheel half (2) comprises a hollow cylindrical collar (4), to which the second toothed wheel half (3) is secured by means of a securing element (6). The aim of the invention is to produce such a divided toothed wheel which only occupies a minimum amount of space from the axial direction and has two halves which are permanently connected together. In order to achieve this, the securing element (6) is designed as an elastically shapeable annular ring disk (8). Said annular ring disk (8) comprises slots (7) which are distributed over the periphery and extend radially outwards from a central opening (5) forming spring tongues (9) between the slots (7). The free ends of the spring tongues (9) have edges (10) that sit on the outer circumference of a component (5) arranged in the central opening (5), in a form-fitting manner, as the spring tongues (9) spring back after the annular ring disk (8) has pressed against the second toothed wheel half.