Harmonic Pin Ring Transmission Load Cell for Radial Torque Sensing
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Solution Overview
Problem
Current technologies lack an effective method for accurately measuring radial forces acting on a crankshaft, which is crucial for determining torque and ensuring proper transmission function in vehicles, particularly in electric bicycles with harmonic pin ring transmissions.
Innovation Solution
A load cell design featuring a cylindrical receiving sleeve and a fastening ring with measuring regions and axial support areas, equipped with strain sensors, is used to accurately measure radial forces transmitted from a bearing's outer ring, allowing for precise determination of torque on a crankshaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If strain sensors are mounted in measuring regions of the load cell, then measurement precision of radial forces is improved, but device complexity increases
Solution Approach 1:
The load cell is segmented into distinct functional regions: a receiving sleeve for mounting the bearing, a fastening ring for attachment to the transmission housing, and measuring regions with strain sensors that connect these components. This segmentation allows each region to be optimized for its specific function while maintaining overall measurement accuracy.
Solution Approach 2:
The load cell acts as an intermediary device between the bearing and the transmission housing, with measuring regions that include strain sensors to detect radial forces. The axial support areas provide structural mediation while the measuring regions capture force data, resolving the contradiction by introducing specialized intermediary components.
2Reliability
If axial support areas are provided on the fastening ring, then reliability of bearing support is improved, but manufacturing precision requirements increase
Solution Approach 1:
The fastening ring is segmented to include dedicated axial support areas that are structurally distinct from the measuring regions. This segmentation allows the axial support areas to be designed with robust geometry that prioritizes reliability while using standard manufacturing tolerances, rather than requiring high-precision machining throughout the entire component.
Solution Approach 2:
Different regions of the fastening ring have different local qualities: the axial support areas are designed with geometry optimized for load-bearing and structural stability, while the measuring regions are designed with features optimized for strain sensor mounting. This local differentiation allows each region to meet its specific performance requirements without imposing excessive precision requirements on the entire component.
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 solution enables precise measurement of radial forces, facilitating accurate torque calculation and improved transmission efficiency in vehicles, particularly in electric bicycles with harmonic pin ring transmissions.
Implementation Method 1
Strain sensors are mounted in at least two of the measuring regions, for example as glued strain gauges
Data Source
AI summary
A method for manufacturing a gear includes providing teeth which are shaped according to an epicyclic construction; wherein: locations on a respective tooth surface of each tooth are each determined by a radial distance from an axis as a function of a cycle angle; the radial distance is in turn determined by an equidistant to a gear trajectory; locations on the gear trajectory are respectively determined by the vector sum of a cycle vector and an epicycle vector; a tail of the cycle vector lies on the axis and a tail of the epicyclic vector lies in the tip of the cycle vector; an epicycle angle of the epicycle vector is n times as large as that cycle angle and a length of the cycle angle is greater than a length of the epicycle angle; and n is a number of the round engagement portions of the harmonic pin ring transmission which is at least three.