Annular Torque Sensor Layout for Wave Reducer Terminal Reliability
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Solution Overview
Problem
Conventional wave reducers in robots face reliability issues due to the high probability of simultaneous load application on terminals of resistance wire portions, which can lead to failure if one terminal malfunctions.
Innovation Solution
An annular body with a torque sensor incorporating two resistance wire portions arranged at circumferentially different positions, ensuring that even if one terminal fails, the other can still function reliably, with a central angle of 90° or more between their positions to minimize simultaneous load application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two sets of resistance wire portions including strain gauges are arranged on the externally toothed gear to improve torque detection reliability, then the reliability of torque detection is improved, but the probability of simultaneous load application on both terminals increases when terminals are arranged at the same circumferential position
Solution Approach 1:
The patent transitions from arranging terminals in the same circumferential position (one-dimensional arrangement) to arranging them at different circumferential positions separated by 90° or more (spatial distribution in multiple dimensions). This dimensional change in terminal arrangement reduces the probability of simultaneous load application while maintaining torque detection reliability.
Solution Approach 2:
The patent introduces asymmetric arrangement of terminals at different circumferential positions (separated by 90° or more) rather than symmetric arrangement at the same position. This asymmetric configuration ensures that when one terminal experiences load, the other terminal is less likely to experience simultaneous load, thereby reducing the harmful effect of simultaneous loading.
2Device complexity
If terminals of resistance wire portions are arranged at the same circumferential position to simplify structure, then device complexity is reduced, but the reliability of torque detection deteriorates due to high probability of simultaneous load application
Solution Approach 1:
The patent distributes terminals along the circumferential direction (adding spatial dimension to terminal arrangement) rather than concentrating them at the same position. This spatial distribution increases the path length and reduces correlation between terminal loads, improving reliability while the 90° separation maintains reasonable structural simplicity.
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 design enhances the reliability of torque detection in wave reducers by reducing the likelihood of simultaneous load application on terminals, allowing for continued functionality even if one terminal becomes non-operational.
Implementation Method 1
a first resistance wire portion having a resistance value changing in accordance with strain of the base; a second resistance wire portion having a resistance value changing in accordance with the strain of the base
Data Source
AI summary
An annular body includes a base, a first resistance wire, a second resistance wire, a first terminal, and a second terminal. The base surrounds a central axis and expands in a direction intersecting the central axis. Resistance values of the first and second resistance wires change according to strain of the base. The first terminal is electrically connected to the end of the first resistance wire. The second terminal is electrically connected to an end of the second resistance wire. The first terminal is at a first position in the circumferential direction. The second terminal is at a second position in the circumferential direction. When viewed in the axial direction, the central angle defined by the first position, the central axis, and the second position is equal to or greater than about 90°.