Double-Flange Torque Sensor Centrifugal Force Correction
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Solution Overview
Problem
Existing torque sensors face measurement errors due to shaft axis misalignment and are sensitive to high-speed centrifugal forces, leading to distorted signals and zero point shifts, especially when shafts are offset in parallel or at angles, and struggle to balance stiffness and sensitivity for precise torque measurement.
Innovation Solution
A double flange torque sensor system with a deformation element of small diameter and rectangular cross-section spring elements, where strain gauges are close to the axis of rotation, minimizing centrifugal forces and allowing for correction of measurement signals through spring elements with different materials and spring constants, enabling precise torque measurement at high speeds and correcting for errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the deformation element is made thicker and stiffer, then measurement precision is improved, but centrifugal forces on strain gauges increase at high speeds
Solution Approach 1:
The patent moves the strain gauges from the outer circumference to the central region along the axial dimension, changing their spatial arrangement from radial to axial positioning. This dimensional repositioning allows the deformation element to maintain necessary stiffness while placing strain gauges in a region experiencing minimal centrifugal force at high speeds.
Solution Approach 2:
The patent applies different local properties to different regions of the deformation element. The central region where strain gauges are positioned has optimized geometry to minimize centrifugal effects, while other regions maintain the structural stiffness needed for accurate torque measurement. This local optimization resolves the contradiction between overall stiffness and local centrifugal force exposure.
2Object-affected harmful factors
If the deformation element is made thinner, then centrifugal forces on strain gauges are reduced, but measurement signal decreases
Solution Approach 1:
The patent changes the geometric parameters of the deformation element, specifically using a hollow cylindrical shape with optimized wall thickness and introducing axial slots. These parameter changes allow the element to maintain adequate stiffness for signal generation while reducing the diameter to minimize centrifugal forces on strain gauges positioned in the central region.
Solution Approach 2:
By positioning strain gauges in the axial direction rather than radial direction, the patent exploits the axial dimension to achieve measurement sensitivity without exposing gauges to high radial centrifugal forces. This dimensional strategy allows thinner deformation elements to maintain measurement capability while reducing speed-related harmful effects.
3Measurement precision
If strain gauges are positioned far from the center of rotation, then measurement sensitivity is improved, but centrifugal forces increase at high speeds
Solution Approach 1:
Instead of positioning strain gauges at the outer radius to maximize leverage and sensitivity, the patent inverts this conventional approach by positioning them in the central region. The measurement principle is inverted from radial lever-arm-based sensing to axial deformation-based sensing, which achieves sensitivity through a different mechanical mechanism that is not compromised by centrifugal forces.
Solution Approach 2:
The patent changes the measurement parameter from radial strain at the outer surface to axial strain in the central region. This parameter change allows the system to maintain measurement sensitivity through axial deformation caused by torque while positioning strain gauges in a location where centrifugal forces are minimal, thus resolving the contradiction between sensitivity and centrifugal force exposure.
4Stability of the object's composition
If the deformation element is made more rigid, then measurement stability is improved, but strain and measurement signal decrease
Solution Approach 1:
The patent employs a composite structural design combining a hollow cylindrical deformation element with axial slots and strategically positioned reinforcement features. This composite geometry provides the necessary rigidity for measurement stability in the torque direction while maintaining sufficient flexibility to generate measurable strain signals, resolving the contradiction between stability and signal strength.
Solution Approach 2:
The patent optimizes the geometric parameters of the deformation element, including wall thickness, slot dimensions, and overall diameter, to achieve a balance point where the structure has sufficient rigidity for stable measurements but enough flexibility to generate adequate strain signals. These parameter optimizations allow simultaneous achievement of measurement stability and signal strength.
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 system achieves precise torque measurement with reduced centrifugal forces and corrected signals, even at high speeds, by maintaining a thin deformation element and using spring elements to correct measurement signals, addressing the limitations of existing sensors in axis alignment and vibration behavior.
Implementation Method 1
Both flanges are connected to a deformation element that deforms elastically under the influence of a torque
Implementation Method 2
Strain gauges are applied at selected points on the deformation element to measure the strain occurring at these points
Implementation Method 3
the distances of the strain gauges from the center of rotation of the double-flange torque transducer can be kept small, so that comparatively low centrifugal forces occur even at high speeds
Data Source
Figure 1
AI summary
The invention relates to a double flange torque sensor equipped with a correction sensor system, having the following characteristics: a deforming element (1) on which strain gauges (2) are fixed, two parallel, disc-shaped securing flanges (3, 4) which are integrally connected to the deforming element (1) and which comprise securing boreholes (5), and at least three rod-shaped spring elements (6) which extend between the flanges (3, 4) and are secured thereto between the securing boreholes (5) or to the outer region of the securing boreholes (5). The spring elements have a rectangular cross-section, the shorter side thereof being oriented radially to the axis of rotation of the double-flange. At least one strain gauge (7) is arranged on each spring element (6). The invention also relates to a method for correcting the measured torque.