Ring Body Angle Scale Segmentation for High-Speed Shaft Fatigue

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing angle measuring systems for high-speed machine parts, particularly shafts, face limitations in maximum permissible speed and fatigue strength due to high centrifugal forces, posing safety concerns.

Innovation Solution

A ring-shaped body with an angle scale featuring radial recesses and elevations, where the sum of central angles defined by recesses is less than those defined by elevations, allowing for positive non-rotatable attachment and optimized geometry to enhance fatigue strength and permissible speed, with the angle scale potentially applied using magnetic or optical methods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a ring-shaped body with angle scale is used for high-speed shafts, then the measurement function is achieved, but the centrifugal forces at high speeds exceed the fatigue strength limits

Engineering Contradiction:
Improvemaximum permissible speedVSAvoidfatigue strength
Core Design Contradiction:
SpeedVSStrength

Solution Approach 1:

The ring-shaped body is segmented into multiple radial recesses and elevations distributed around the circumference. This segmentation creates a more uniform stress distribution pattern, preventing stress concentration at any single location and thereby increasing the fatigue strength to withstand high-speed centrifugal forces.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The recesses and elevations are strategically positioned at specific locations around the ring to optimize stress distribution. By localizing geometric features rather than making the entire structure uniform, the design achieves high fatigue strength while maintaining the necessary measurement functionality.

Inventive Principle:
Principle #3Local quality

2Strength

If the sum of central angles of recesses is made smaller than that of elevations, then fatigue strength increases, but the attachment geometry becomes more complex

Engineering Contradiction:
Improvefatigue strengthVSAvoidgeometry complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The design employs asymmetric distribution of recesses and elevations around the ring circumference. By making the angular distribution non-uniform (with recesses occupying smaller total angle than elevations), the structure achieves optimized stress distribution and higher fatigue strength while maintaining practical manufacturability.

Inventive Principle:
Principle #4Asymmetry

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

The design achieves significantly higher permissible speeds and required fatigue strength, minimizing mechanical stress and maximizing operational safety at high speeds.

Implementation Method 1

The angle scale can have, for example, an optical or a magnetic graduation, which can be scanned accordingly

Methodology Applied
Scientific EffectOptical scanning:

Implementation Method 2

the angle scale can have, for example, an optical or a magnetic graduation, which can be scanned accordingly

Methodology Applied
Scientific EffectMagnetic field detection: Magnetic Field

Implementation Method 3

these are exposed to enormous centrifugal forces

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 4

At least one of the recesses is suitable for positive, non-rotatable attachment to the machine part

Methodology Applied
Scientific EffectMechanical interference fit: Mechanical Fastener

Data Source

PatentEP2019291B1Body with angle scaling and its use
Publication Date: 2012.08.15 DR JOHANNES HEIDENHAIN GMBH
  • EP2019291B1 patent drawingFigure 1~2b
  • EP2019291B1 patent drawingFigure 3~4
  • EP2019291B1 patent drawingFigure 5

AI summary

The annular body (1) has radial recesses (3,4) and an elevation at an inner periphery of the annular body. An angular scale (2) is provided, where the sum of angle at center, which is defined by starting points (S epsilon-3,S epsilon-4,S alpha-3,S alpha-4) and ending points (E alpha-2,E alpha-3,E epsilon-3,E epsilon-5) elevation that is smaller than the sum of angle at center. The angles at center are each defined by starting and ending points of the recesses.