Torque Sensor Shunt Spoke Radial Deformation Control

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Solution Overview

Problem

Existing torque sensors face challenges in achieving compactness, simplicity, and high measurement accuracy due to mechanical overload and slip issues in screw connections, which degrade measurement precision.

Innovation Solution

A torque sensor design featuring a base body with radially alternating connecting walkways of different mechanical properties, including thinner measuring spokes and side closing spokes that minimize radial deformation on the outer flange, along with a concentric attack flange for overload protection and a rubber-like sealing membrane for fluid sealing, enhancing measurement accuracy and resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional torque sensors use uniform connecting webs, then structural simplicity is maintained, but measurement accuracy deteriorates due to radial deformation at the outer flange causing screw connection slippage

Engineering Contradiction:
Improvetorque measurement accuracyVSAvoidconnecting web structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by differentiating the properties of connecting webs at different locations. The inner connecting webs have uniform width throughout, while the outer connecting webs have variable width - wider at the inner radius and narrower at the outer radius. This local differentiation allows the outer webs to reduce radial deformation at the flange (improving measurement accuracy) while the inner webs maintain structural integrity, resolving the contradiction between accuracy and structural simplicity.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If the torque sensor uses thinner measuring spokes to increase strain and resolution, then measurement resolution improves, but structural strength deteriorates leading to potential mechanical failure

Engineering Contradiction:
Improvetorque measurement resolutionVSAvoidspoke structural strength
Core Design Contradiction:
Measurement precisionVSStrength

Solution Approach 1:

The patent segments the connecting webs into two distinct functional groups: inner connecting webs that provide structural support and outer connecting webs that minimize radial deformation. This segmentation allows the measuring spokes to be made thinner for higher strain and resolution while the outer connecting webs compensate by providing the necessary structural strength to prevent failure, thus resolving the contradiction between resolution and strength.

Inventive Principle:
Principle #1Segmentation

3Volume of moving object

If the torque sensor uses a compact design with integrated components, then device size is reduced, but manufacturing complexity increases

Engineering Contradiction:
Improvetorque sensor sizeVSAvoidmanufacturing simplicity
Core Design Contradiction:
Volume of moving objectVSEase of manufacture

Solution Approach 1:

The patent merges multiple functions into the base body structure: the connecting webs are integrally formed as part of the base body, and the flanges are also integral components. This merging creates a compact design with reduced overall size while the consistent material composition and integrated structure actually simplify manufacturing compared to assembly-based approaches, resolving the contradiction between compactness and manufacturing ease.

Inventive Principle:
Principle #5Merging (Combining)

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 improved measurement accuracy and resolution by minimizing slip in screw connections and preventing fluid interference, while maintaining a compact and cost-effective structure.

Implementation Method 1

to measure a torque, a deformation (in particular bending) of the measuring spokes is primarily determined by means of suitable measuring sensors

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

the width of the second connecting webs is less on the radial outside than on the radial inside, with the width of the second connecting webs decreasing continuously from radial inside to radial outside

Methodology Applied
Scientific EffectGeometric stress distribution: Geometry

Data Source

PatentEP3507581B1Torque sensor having a shunt spoke
Publication Date: 2022.11.30 SENSODRIVE
  • EP3507581B1 patent drawingFigure 1~2
  • EP3507581B1 patent drawingFigure 3~4
  • EP3507581B1 patent drawingFigure 5~6

AI summary

The invention relates to a torque sensor having a main body (601), which extends in a radial direction (Y) of the main body from a ring-shaped inner flange (603) with first force transmission points (605), via a mechanically weakened sensor portion (607) that is equipped with measurement value recorders (10, 20) that generate output signals, to a ring-shaped outer flange (509; 609) with second force transmission points (611), wherein the mechanically weakened sensor portion (607) comprises radially extending first connecting webs (619a) and second connecting webs (619b), which have different mechanical properties and which are arranged in alternating fashion in the circumferential direction.