Helical Gear Connection Assembly Axial Load Distribution

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Solution Overview

Problem

Helical gearing in rotary motion transmission devices experiences deformation and failure due to axial loads, leading to reduced smoothness, increased noise, and shortened lifespan, particularly in electric steering systems, where high axial forces are common, and existing solutions either compromise on torque transmission or increase manufacturing costs and noise.

Innovation Solution

A connection arrangement with a gear wheel featuring helical gearing and a component with a connecting section that includes depressions or elevations, where the connection helix angle α is defined relative to the tooth helix angle β, allowing for uniform axial force transmission and reducing tilting moments, enabling the use of softer materials for noise reduction while maintaining torque transmission capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If axial loads are transmitted by a shoulder against which the gear hub rests, then the connection is simple to manufacture, but point loads cause tilting moments leading to gear detachment and connection failure

Engineering Contradiction:
Improveconnection simplicityVSAvoidconnection reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The connection interface is segmented into multiple recesses or protrusions distributed around the circumference, transforming a single-point load into multiple distributed contact points. This segmentation prevents concentration of axial loads at one location, eliminating tilting moments while maintaining manufacturing simplicity through modular geometry

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connection design transitions from axial-only load transmission to combined axial and radial load distribution by introducing helical recesses/protrusions. The helical geometry adds a radial dimension to force transmission, distributing axial loads through inclined contact surfaces that engage both axial and radial force components

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Strength

If the helix angle of helical gearing is reduced to reduce stress on the connection assembly, then connection stress decreases, but uniform torque transmission and low noise generation advantages are largely negated

Engineering Contradiction:
Improveconnection strengthVSAvoidtorque transmission quality
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The helical gear connection is segmented into discrete recesses or protrusions that independently carry load, allowing the effective helix angle at each contact point to be optimized for strength while maintaining the overall gear helix angle for smooth torque transmission. This segmentation decouples connection strength requirements from gear meshing quality requirements

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connection interface employs local helical geometry with specific angles optimized for load-bearing capacity at the connection points, while the gear teeth maintain their own helix angles optimized for smooth engagement. This local quality differentiation allows each component to be optimized for its specific function without compromising the other

Inventive Principle:
Principle #3Local quality

3Strength

If very stiff materials such as steel are used to reduce stress on the connection assembly, then connection stress decreases, but manufacturing costs, weight, and noise generation increase compared to softer materials

Engineering Contradiction:
Improveconnection strengthVSAvoidgear weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The connection design changes the geometric parameters of the recesses or protrusions to optimize load distribution and stress characteristics, allowing softer materials to achieve the same connection strength as stiff materials. By optimizing the helical angle and dimensions of the connection features, the material strength requirement is reduced, enabling use of lighter, noisier materials

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3276212B1Connection assembly for connecting a component, such as a shaft, hub, socket or the like with a gearwheel with the cogged gear having helical gear teeth
Publication Date: 2020.09.16 IMS GEAR SE & CO KGAA
  • EP3276212B1 patent drawingFigure 1~2b
  • EP3276212B1 patent drawingFigure 3~4
  • EP3276212B1 patent drawingFigure 5~6b

AI summary

The present invention relates to a connection arrangement for connecting a component (12) to a gear (14), wherein the gear (14) has helical teeth (26) with a helix angle (β) and a first connection section (18), and the component (12) has a second connection section (20) with which the component (12) can be connected to or is connected to the first connection section (18), wherein the component (12) has at least one recess (28) or elevation (28) in the second connection section (20) that is in operative contact with the first connection section (18) when the component (12) is connected to the first connection section (18), wherein the recess (28) has a connection helix angle (α) and the connection helix angle (α) is defined as follows: 0° < α ≤ β.The invention further relates to a device for transmitting a rotary motion, comprising a rotatable component (12) and a gear (14), wherein the gear (14) and the component (12) are connected by such a connecting arrangement (16).