Crankshaft Load Cell Assembly for Decoupled Radial Force Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing technologies lack an effective method to accurately measure radial forces on a crankshaft, which is crucial for determining torque and supporting bearings in transmission systems, especially in electric bicycles and internal combustion engines.
Innovation Solution
A load cell design featuring a cylindrical receiving sleeve, a fastening ring with axial support areas and measuring regions, and strain sensors to measure radial forces, allowing for the determination of torque applied to a crankshaft by decoupling radial and axial forces and providing precise force measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a bearing assembly is used to support a crankshaft, then the bearing can withstand radial and axial forces, but the radial forces cannot be accurately measured for torque determination
Solution Approach 1:
The bearing assembly is segmented into functionally distinct components: axial support areas that handle axial forces, and measuring regions with strain sensors that measure radial forces. This segmentation allows independent optimization of each function and enables precise radial force measurement without compromising axial support capability.
Solution Approach 2:
Strain sensors are introduced as intermediary elements in the measuring regions, positioned between the receiving sleeve and fastening ring. These sensors act as mediators that convert mechanical radial forces into measurable electrical signals, enabling accurate torque determination while maintaining the structural integrity of the bearing assembly.
2Measurement precision
If strain sensors are mounted in measuring regions to measure radial forces, then torque can be determined, but the device requires precise alignment and installation
Solution Approach 1:
The measuring regions are pre-formed during manufacturing with integrated mounting features for strain sensors. This preliminary preparation ensures that sensors are positioned at optimal locations for maximum measurement accuracy and simplifies the installation process, as sensors can be directly mounted in the pre-prepared measuring regions without complex alignment procedures.
3Measurement precision
If axial support areas are separated from measuring regions by radial slots, then axial and radial forces are decoupled, but the load cell structure becomes more complex
Solution Approach 1:
The load cell structure is segmented into axial support areas and measuring regions, separated by radial slots. This segmentation physically decouples the transmission paths for axial and radial forces, ensuring that axial forces do not interfere with radial force measurements. The slots create distinct load paths that can be independently optimized for their respective force components.
Solution Approach 2:
Different regions of the load cell are given different local qualities: axial support areas are designed with geometry optimized for axial load bearing, while measuring regions are configured with strain sensors and geometry optimized for radial force measurement. The radial slots create local discontinuities that prevent cross-contamination of force components, allowing each region to perform its specific function with high precision.
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
Enables accurate measurement of radial forces, facilitating the calculation of torque and supporting bearings, improving motor support regulation in electric bicycles and enhancing mechanical drive efficiency by decoupling radial and axial forces, thus providing precise force measurement with minimal space requirements.
Implementation Method 1
Strain sensors are mounted in at least two of the measuring regions, for example as glued strain gauges. The measuring regions are provided for receiving radial forces of the receiving sleeve, which are transmitted from the ring of the bearing to the measuring regions.
Data Source
AI summary
A measuring device with a crankshaft and a load cell for determining a radial force acting on the crankshaft having a receiving sleeve for receiving a bearing ring and a fastening ring for attaching the load cell in a transmission housing. Axial support areas are provided on the fastening ring for axially supporting the outer ring of the first bearing. Moreover, measuring regions for receiving radial forces of the receiving sleeve are provided which connect the receiving sleeve with the fastening ring. Strain sensors are attached to at least two of the measuring regions. An evaluation electronics is connected to the strain sensors.