Spline Shaft-Hub Coupling With Offset Teeth for Zero Backlash
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Solution Overview
Problem
Existing shaft-hub connections in motor vehicles experience undesirable noises such as 'ping noise' due to torsional backlash between tooth flanks, which is exacerbated by higher wheel torques and recuperation in electric vehicles, and prior solutions like sinusoidal tooth flanks are complex and costly to manufacture.
Innovation Solution
A shaft-hub connection design with offset toothing regions and selective tooth flank engagement, eliminating backlash by ensuring the first toothing region is longer than the second, and using a guide toothing area to facilitate assembly, thereby preventing relative movement and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If sinusoidal tooth flanks are used to eliminate backlash, then noise is reduced, but manufacturing complexity and cost increase
Solution Approach 1:
The toothing is divided into multiple toothing regions along the axial direction, with each region having a specific function (engagement, guidance, spacing). This segmentation allows the use of simple linear tooth flanks in each region while achieving the overall effect of backlash elimination through the coordinated arrangement of multiple regions, avoiding the need for complex sinusoidal profiles.
Solution Approach 2:
A guide toothing area is introduced as an intermediary element between the first and second toothing regions. This guide area facilitates the assembly process and ensures proper alignment, enabling the use of simple linear tooth flanks while maintaining precise engagement and eliminating backlash without requiring complex manufacturing.
2Object-affected harmful factors
If sinusoidal tooth flanks are used to eliminate backlash, then noise is reduced, but contact surface area decreases
Solution Approach 1:
By dividing the toothing into multiple axial regions with linear tooth flanks, the total contact surface area is increased compared to sinusoidal profiles. The segmentation allows for larger engagement surfaces in each region while maintaining the backlash-free engagement through the offset arrangement of toothing regions.
3Ease of manufacture
If offset toothing regions are used to eliminate backlash, then noise is reduced and manufacturing is simplified, but assembly complexity increases
Solution Approach 1:
The guide toothing area acts as an intermediary that simplifies assembly by guiding the shaft into proper alignment with the hub during the assembly process. This intermediary element compensates for the offset arrangement of toothing regions, making assembly easier despite the complex toothing configuration.
Solution Approach 2:
The guide toothing area performs the preliminary action of aligning and guiding the components during assembly before the final engagement of the main toothing regions. This preliminary alignment action simplifies the overall assembly process by ensuring proper positioning before load-bearing engagement.
Data Source
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AI summary
A shaft-hub connection comprises a shaft (12) and a hub which engage with one another for conjoint rotation about an axis of rotation (18) via a first toothing (16) and a second toothing. The first toothing (16) has a first toothing region (16-1) and a second toothing region (16-2), wherein the first toothing region (16-1) and the second toothing region (16-2) are, as viewed in the circumferential direction (u), arranged offset by a dimension (d) in such a way that the first toothing region (16-1) engages with the second toothing via front tooth flanks as viewed in the circumferential direction (u), and the second toothing region (16-2) engages with the second toothing via rear tooth flanks as viewed in the circumferential direction (u).