Hollow Shaft Sensor Mounting via Radial Projections

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing machine elements with hollow shafts face challenges in reliably and precisely detecting mechanical stresses over time, as conventional sensor devices are not securely fixed, leading to potential damage and incorrect measurements, and require significant assembly effort.

Innovation Solution

A sensor device is fixed within the hollow shaft section using radially inwardly protruding formations with a circumferentially profiled surface, providing a form-fitting engagement and axial prestressing to ensure precise and long-term stress detection without external interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the sensor device is adhesively fixed or force-fitted within the hollow shaft's interior, then the position of the sensor device can be defined with relative precision, but the sensor device is only conditionally suitable for comprehensively detecting axial and radial deformations and requires considerable assembly effort

Engineering Contradiction:

Improvedetection precision of mechanical stressesVSAvoidassembly effort

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The sensor device is designed to automatically engage with the radially inwardly projecting projections during insertion. The circumferentially profiled surfaces of the projections automatically align and lock the sensor device in the correct position, eliminating the need for complex external fixing mechanisms or precise manual positioning during assembly.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The radially inwardly projecting projections with circumferferentially profiled surfaces act as intermediary elements between the hollow shaft and the sensor device. These projections provide both positioning and preloading functions, serving as a mechanical interface that simplifies assembly while ensuring comprehensive deformation detection.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the sensor device is arranged in the hollow shaft cavity, then the sensor device is protected from external influences and environmental conditions, but a permanently precise fixing of the sensor device within the cavity is not required for vibration and noise detection

Engineering Contradiction:

Improveprotection from external influencesVSAvoiddetection precision of mechanical stresses

Core Design Contradiction:

Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The radially inwardly projecting projections are pre-formed as integral features of the hollow shaft before sensor installation. These projections are designed with specific circumferferentially profiled surfaces that automatically provide both protection and precise positioning when the sensor device is inserted, eliminating the need for separate protective and positioning steps.

Inventive Principle:

Principle #10Preliminary action

3Measurement precision

If external sensors are attached to the surface of the machine element, then the sensor values can be recorded and evaluated, but the sensors impose restrictions on handling and use and may be subjected to excessive stress

Engineering Contradiction:

Improvedetection capability of mechanical stressesVSAvoidhandling and use restrictions

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

Instead of attaching sensors externally to the hollow shaft surface, the sensor device is inverted and placed inside the hollow shaft cavity. The radially inwardly projecting projections with circumferferentially profiled surfaces provide the necessary mechanical interface from the inside, reversing the conventional mounting approach and eliminating external restrictions on handling and use.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentEP3662240B1Machine element having a sensor device and method for producing a machine element

Publication Date: 2022.03.09 CORE SENSING GMBH

Figure 1~4
Figure 5~6
Figure 7~8

AI summary

In a machine element comprising a hollow shaft section and comprising a sensor device (2) for detecting a mechanical load acting on the hollow shaft section, the sensor device (2) is arranged in the hollow shaft section, wherein the hollow shaft section has a first moulding (12) projecting radially inwards and a second moulding (20) projecting radially inwards, and the sensor device (2) is interlockingly secured with an axial pretensioning between the first moulding (12) projecting radially inwards and the second moulding (20) projecting radially inwards. In a production method for producing the machine element, in a first moulding step, a first moulding (12) protruding radially inwards is generated in the hollow shaft section of the machine element, in a subsequent sensor arrangement step, a sensor device (2) is interlockingly attached in the hollow shaft section on the first moulding (12) protruding radially inwards, and in a subsequent securing step, the second moulding (20) protruding radially inwards is generated in the hollow shaft section, via which the sensor device (2) is interlockingly secured with an axial pretensioning between the first moulding (12) protruding radially inwards and the second moulding (20) protruding radially inwards