Connection Shaft Tolerance Zoning for Stable Drive Shaft Assembly
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current drive units require precise dimensional tolerance between drive and connection shafts for welding, increasing manufacturing costs and effort, while also risking damage from air trapped during assembly.
Innovation Solution
Implementing a receiving recess with different axial portions having distinct dimensional tolerance characteristics, creating a clearance or transition fit at one end and an interference fit at the other, allowing for easier assembly and alignment with reduced manufacturing effort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If precise dimensional tolerance is maintained between drive shaft and connection shaft for welding, then connection stability is improved, but manufacturing cost and effort increase
Solution Approach 1:
The receiving recess is divided into two axial portions with different dimensional tolerance characteristics. The first axial portion has tighter tolerances to ensure stable connection and alignment, while the second axial portion has looser tolerances to reduce manufacturing effort and cost. This segmentation allows different tolerance requirements in different zones of the same component.
Solution Approach 2:
Different portions of the receiving recess are assigned different quality levels in terms of dimensional tolerance. The first axial portion (where alignment and stability are critical) receives higher quality control with tighter tolerances, while the second axial portion (where alignment is less critical) accepts lower quality with looser tolerances, optimizing the balance between performance and manufacturing cost.
2Reliability
If interference fit is applied throughout the entire receiving recess, then alignment and connection stability are improved, but assembly difficulty and forces required increase
Solution Approach 1:
The receiving recess is segmented into a first axial portion with interference fit characteristics for alignment and stability, and a second axial portion with clearance or transition fit characteristics that facilitate easier assembly. This segmentation reduces the overall assembly force required while maintaining the necessary alignment quality in the critical first portion.
Solution Approach 2:
The interference fit is applied locally only in the first axial portion where alignment and connection stability are most critical, while the second axial portion uses clearance or transition fit to ease assembly. This local application of interference fit reduces total assembly difficulty while preserving alignment quality where needed.
3Reliability
If tight dimensional tolerance is applied to the receiving recess, then connection stability is improved, but air trapping during assembly increases causing damage risk
Solution Approach 1:
The receiving recess is segmented such that the second axial portion has looser dimensional tolerance characteristics that create clearance or transition fit. This looser fit in the second portion provides space for air to escape during assembly, preventing air trapping and the associated damage risks, while the first portion maintains tight tolerances for stability.
Solution Approach 2:
Different quality levels of dimensional tolerance are applied to different portions of the receiving recess. The first axial portion maintains high quality tight tolerances for connection stability, while the second axial portion uses lower quality looser tolerances that enable air escape during assembly, locally eliminating the air trapping harmful effect where it is least critical to stability.
Data Source
Figure 1
Figure 2
AI summary
A drive unit comprising at least one motor, at least one drive shaft and at least one connection shaft, wherein the connection shaft includes at least one receiving recess having a receiving opening at a first end side and is formed closed at a second end side. A first axial portion of the receiving recess has first dimensional tolerance characteristics with respect to the diameter, and the drive shaft is at least partially inserted into the receiving recess. A second axial portion of the receiving recess has second dimensional tolerance characteristics with respect to the diameter, and the first dimensional tolerance characteristics are different from the second dimensional tolerance characteristics, so that a clearance fit or transition fit is formed in the first portion between the drive shaft and the connection shaft and an interference fit is formed in the second portion between the drive shaft and the connection shaft.