Disc-Shaped Torque Transducer Design for Compact Power Tools
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Solution Overview
Problem
Existing torque transducers for power tools and rotating machinery often increase the size and weight of the tools, making them unsuitable for limited space environments and leading to inaccurate fastener tension measurements and operator fatigue.
Innovation Solution
A compact torque transducer design featuring a hub, web, and rim configuration with specific thickness ratios and keyways, integrated with a strain gage for accurate torque measurement, which reduces stress concentrations and allows for real-time feedback to control tool operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional torque transducers are used to measure torque output, then torque measurement capability is achieved, but the axial dimensions increase the overall size of the tool
Solution Approach 1:
The transducer is segmented into three main components: a hub with strain gages, a web connecting the hub to the rim, and a rim portion. This segmentation allows each component to be optimized independently for its specific function while maintaining overall compactness.
Solution Approach 2:
The design transitions from a conventional axial configuration to a radial configuration where the rim extends radially outward from the web. This dimensional change allows the measurement function to be achieved without increasing axial length, as the rim's radial thickness provides the necessary structural dimension for torque sensing.
2Reliability
If larger transducers are used to ensure accurate measurement, then measurement reliability is improved, but the tool weight increases
Solution Approach 1:
The strain gages are strategically placed only on the hub portion where stress concentrations occur during torque transmission. This localized sensing approach provides reliable torque measurement without requiring the entire transducer structure to be oversized, thereby minimizing weight while maintaining measurement reliability.
3Measurement precision
If conventional transducer designs are used, then torque measurement is achieved, but the tool becomes unwieldy and contributes to operator fatigue
Solution Approach 1:
The transducer design incorporates a dynamic web structure that flexes under torque load, allowing the strain gages to measure deformation. This dynamic response enables accurate measurement while keeping the overall structure lightweight and balanced, improving ease of operation and reducing operator fatigue.
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 provides accurate torque measurement while minimizing tool size and weight, enabling reproducible fastener tensioning and reducing operator fatigue, even in confined spaces.
Implementation Method 1
A strain gage is mounted on the web to measure deformation of the web
Data Source
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AI summary
A torque transducer 58 comprising: a hub 60 defining an aperture 62 therethrough, the aperture defining an axis, the hub 60 having a hub first end 66 and a hub second end 68 spaced along the axis, and defining a first thickness 70 in a radial direction, perpendicular to the axis; a web 74 coupled to the hub 60 at the hub first end 66, the web 74 defining an unbroken ring in a plane perpendicular to the axis and defining a second thickness 76 measured in the direction of the axis, wherein the second thickness 76 is less than one half of the first thickness 70; and a rim 80 having a rim first end 82 and a rim second end 84 spaced from the rim first end 82 along the axis, the rim 80 coupled to the web 74, the rim 80 defining a perimeter that includes at least one keyway 100 in an exterior of the perimeter.