Elastic Gear Flange Assembly for Axial Flex and Rotational Precision
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Solution Overview
Problem
Existing gearing systems with elastic gears face challenges in achieving a balance between stiffness in the circumferential direction and flexibility in the axial direction, particularly in applications like electric camshaft adjusters and variable compression ratio devices, where precise rotational movement transfer and deformation absorption are required.
Innovation Solution
The design incorporates an elastic gear with a pot-like shape, featuring a radially outward flange held by multiple fastening points and axial play, allowing for directional stiffness and flexibility, with a cylindrical toothed section and a flat or corrugated flange for enhanced axial flexibility and reduced circumferential stiffness, ensuring precise rotational movement transfer and deformation absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the elastic gear is fastened to the housing component with multiple fastening points, then the gear is securely held without circumferential play, but the gear becomes too stiff in the axial direction preventing necessary deformation
Solution Approach 1:
The connecting assembly provides different fastening characteristics at different locations: at the fastening points (e.g., bolt locations) the gear is securely constrained to prevent circumferential play, while in the circumferential sections between fastening points the gear is allowed axial play. This local differentiation of constraints enables the gear to be stable circumferentially while remaining flexible axially for deformation absorption.
2Measurement precision
If the gear is made completely rigid to ensure precise rotational movement transfer, then precision is improved, but the gear cannot absorb deformation from the wave generator
Solution Approach 1:
The gear's connection to the housing is segmented into discrete fastening points rather than being continuously constrained. This segmentation allows the gear to maintain precision in rotational movement transfer while absorbing deformation through elastic flexing between the fastening points, as the gear can deform axially in the circumferential sections without compromising rotational accuracy.
3Adaptability or versatility
If axial play is introduced between the flange and housing component, then the gear can deform axially, but the gear may become unstable in the axial direction
Solution Approach 1:
The connecting assembly creates localized stability at the fastening points while maintaining global axial flexibility. The fastening points (e.g., bolted connections) provide axial stability where needed, while the circumferential sections between fastening points allow axial play for deformation. This local differentiation enables the gear to deform axially for wave absorption while remaining stable overall.
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 configuration achieves high precision in rotational movement transfer and deformation absorption, particularly in electric camshaft adjusters and variable compression devices, by decoupling the elastic gear from the housing exclusively in the axial direction, allowing unhindered radial deformation while maintaining stiffness in the circumferential direction.
Implementation Method 1
the elastic gear is thus held on the housing component without play in the circumferential direction and simultaneously with play in the axial direction
Data Source
AI summary
A gearing (1), in particular a strain wave gearing, including an elastic gear (2) having a flange (16), which flange is fastened to a housing component (7) of the gearing (1). A connecting assembly (8) for retaining the flange (16) on the housing component (7) includes a plurality of fastening points (14), wherein, outside of the fastening points (14), the connecting assembly (8) has axial play between the flange (16) and the housing component (7), with respect to the center axis (M) of the gear (2).