Wave Washer Outward Protrusions for Shaft Alignment

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Solution Overview

Problem

Existing wave washers often experience positional offset issues with target members, leading to non-uniform load application, which can affect the performance and efficiency of rotary shaft supporting devices in electric motors.

Innovation Solution

A wave washer design featuring an annular portion with outward protrusions from the outer periphery, located at connection portions between first and second protrusions, which helps to minimize positional offset and evenly distribute load, thereby improving the alignment and operational stability of the rotary shaft supporting device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the wave washer is designed with a clearance between the wave washer and the holding case, then the wave washer can accommodate misalignment, but the positional offset between the wave washer and the rolling bearing increases leading to non-uniform load application

Engineering Contradiction:
Improveaccommodation of misalignmentVSAvoidpositional offset between wave washer and rolling bearing
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The wave washer incorporates outward protrusions at specific locations on its outer periphery that engage with corresponding inward protrusions on the holding case. This localized engagement creates specific positioning points that maintain alignment between the wave washer and rolling bearing while still allowing for general misalignment accommodation through the wave washer's flexible geometry.

Inventive Principle:
Principle #3Local quality

2Force

If the wave washer applies a load to the rolling bearing, then the rolling bearing maintains proper contact and support, but non-uniform load distribution occurs due to positional offset

Engineering Contradiction:
Improveload application to rolling bearingVSAvoiduniformity of load distribution
Core Design Contradiction:
ForceVSManufacturing precision

Solution Approach 1:

The outward protrusions are strategically positioned at specific locations on the wave washer's outer periphery to engage with corresponding features on the holding case. This localized engagement creates predetermined load application points that ensure uniform load distribution to the rolling bearing, preventing concentration of forces at offset locations.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The wave washer geometry is pre-designed with integrated outward protrusions that automatically engage with the holding case during assembly. This preliminary configuration ensures proper alignment and uniform load distribution is established before the wave washer begins its load-bearing function, eliminating the need for additional adjustment mechanisms.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If the wave washer has a simple annular structure, then the device complexity is reduced, but the ability to control positional offset and ensure uniform load distribution is insufficient

Engineering Contradiction:
Improvestructural simplicity of wave washerVSAvoidcontrol of positional offset
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The wave washer's outer periphery is segmented into multiple sections, with outward protrusions formed at specific locations. This segmentation allows the wave washer to maintain its simple annular overall structure while incorporating localized features that provide precise positioning and uniform load distribution capabilities.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2689989B1Wave washer, rotary shaft supporting device including the wave washer, and electric motor including the rotary shaft supporting device
Publication Date: 2017.11.15 JTEKT CORP
  • EP2689989B1 patent drawingFigure 1
  • EP2689989B1 patent drawingFigure 2
  • EP2689989B1 patent drawingFigure 3

AI summary

A wave washer (50) is used for a shaft supporting device of an electric power steering system. The wave washer (50) has an annular portion (51) and six outward protrusions (57). The annular portion (51) has first protrusions (54) that protrude in a first axial direction and second protrusions (55) that are formed so as to continuous with the first protrusions (54) and that protrude in a second axial direction. Each outward protrusion (57) protrudes from an outer periphery of the annular portion (51) in a radially outward direction (RA) of the radial direction (R) of the annular portion (51).