Angle Measuring Shaft Groove for Lubricant Management

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Solution Overview

Problem

Existing angle measuring devices face challenges in achieving high measuring accuracy due to contamination from lubricants, which can lead to measurement errors and optical interference, particularly when lubricants escape and reflect on the material measure.

Innovation Solution

A structural unit for an angle measuring device featuring a one-piece shaft with a shoulder and a roller bearing, where a radial groove is integrated to collect and manage lubricants, minimizing contamination by creating a sealing effect and reducing wobbling errors through precise machining and capillary channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a roller bearing is used to support the shaft, then the mechanical stability and load-bearing capacity are improved, but lubricant leakage occurs which contaminates the material measure and degrades measurement accuracy

Engineering Contradiction:
Improveload-bearing capacityVSAvoidmeasurement accuracy
Core Design Contradiction:
StrengthVSMeasurement precision

Solution Approach 1:

The harmful lubricant is extracted from the potential contamination path by introducing a groove structure that collects and channels the lubricant away from the material measure. The groove acts as a separate collection zone that isolates the lubricant from the optical measurement area, thus maintaining measurement precision while preserving the roller bearing's load-bearing function.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The groove structure serves as an intermediary element between the roller bearing and the material measure. It intercepts the lubricant that escapes from the roller bearing and redirects it into a cavity, preventing direct contact between the lubricant and the material measure. This intermediary structure resolves the contradiction by allowing the roller bearing to function while protecting the measurement area.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-generated harmful factors

If a separate add-on body with a channel is used to drain lubricant, then lubricant management is improved, but the structural complexity increases and measurement accuracy decreases due to misalignment and wobbling errors

Engineering Contradiction:
Improvelubricant managementVSAvoidmeasurement accuracy
Core Design Contradiction:
Object-generated harmful factorsVSMeasurement precision

Solution Approach 1:

The groove and cavity structures are merged directly into the shaft body as integral components, eliminating the need for separate add-on bodies. This integration ensures precise alignment between the shaft, material measure, and lubricant management structures, removing the source of misalignment and wobbling errors while maintaining effective lubricant drainage.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The shaft is segmented into functional zones: the measurement area with the material measure, the bearing support area with the roller bearing, and the lubricant management area with the groove and cavity. This segmentation allows each zone to perform its specific function independently while maintaining precise relative positioning, thus improving lubricant management without compromising measurement accuracy.

Inventive Principle:
Principle #1Segmentation

3Manufacturing precision

If the material measure is mounted on a shaft with a shoulder, then the axial positioning is improved, but lubricant can escape along the shoulder and contaminate the scale

Engineering Contradiction:
Improveaxial positioningVSAvoidlubricant contamination
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The groove is introduced as an intermediary structure between the shoulder and the roller bearing. It intercepts lubricant that would otherwise escape along the shoulder surface and redirect it into the cavity. This maintains the shoulder's axial positioning function while preventing lubricant contamination of the scale.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The groove is strategically positioned in the local area where lubricant escape is most likely to occur (between the roller bearing and shoulder). This localized intervention addresses the contamination problem at its source without affecting the overall axial positioning provided by the shoulder, thus maintaining manufacturing precision while eliminating harmful lubricant escape.

Inventive Principle:
Principle #3Local quality

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 design ensures high measurement accuracy by preventing lubricant contamination of the material measure, reducing eccentricity and wobbling errors, and maintaining optical clarity, thereby enhancing the reliability and precision of angle measurements.

Implementation Method 1

Zwischen der Schulter und dem Rollenlager ist mindestens eine in radialer Richtung ausgerichtete Grille angeordnet, die mit einem zur Aufnahme von Schmiermittel geeigneten Hohlraum verbunden ist

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP2378251B1Component for an angle measuring device
Publication Date: 2015.10.14 DR JOHANNES HEIDENHAIN GMBH
  • EP2378251B1 patent drawingFigure 1
  • EP2378251B1 patent drawingFigure 2~3b
  • EP2378251B1 patent drawingFigure 4

AI summary

The invention relates to a component for an angle measuring device comprising a shaft (1) with a measuring element (2) for measuring a rotational movement about an axis (Z). The shaft (1) has as an integral component a shoulder (1.1) on which a rolling bearing (3) is mounted in an axial stop. A groove (4.2) is arranged between the shoulder (1.1) of the shaft (1) and the rolling bearing (3), which is oriented with a radial direction component and is connected to a cavity (4.4) for receiving lubricant, wherein the cavity (4.4) is bounded in the radial direction by a ring (3.1) of the rolling bearing (3) and the shaft (1).