Hex-Axial Force Sensor Dual Stoppers Strain Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Force sensors used in robot arms face reliability issues due to varying stiffness in different axis directions, leading to potential strain body damage and reduced safety when excessive external forces are applied.
Innovation Solution
A hex-axial force sensor design featuring a cylindrical main body, movable body with circular openings, strain body, and dual stoppers (first and second stoppers) that limit displacement and prevent excessive deformation by adjusting clearance distances to manage strain body deformation accurately across X-, Y-, and Z-axis directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single stopper is used to protect the strain body, then the structure is simple, but the safety is reduced when stiffness varies across axis directions
Solution Approach 1:
The protection mechanism is segmented into two independent stoppers: a first stopper that limits displacement in the Z-axis direction, and a second stopper that limits displacement in the X-Y plane directions. This segmentation allows each stopper to be optimized for specific directional protection, ensuring reliable strain body protection even when stiffness varies across different axis directions.
2Reliability
If the stopper is positioned close to the strain body, then the protection is effective, but the operating point shifts to high-load side when stiffness is high
Solution Approach 1:
Different stoppers are positioned at different locations optimized for their respective protection needs: the first stopper is positioned at a first distance in the Z-axis direction, while the second stopper is positioned at a second distance in the X-Y plane directions. This localized positioning ensures that each stopper operates at appropriate load levels for its specific directional protection function.
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 solution effectively prevents strain body damage and enhances reliability by ensuring the strain body does not exceed its deformation limits, even with varying stiffness across axis directions, while allowing for downsizing and reducing the thickness of the force sensor.
Implementation Method 1
a strain body fixed to the main body and the movable body and deformable according to the movement of the movable body
Implementation Method 2
a first stopper arranged inside each of the openings and including a first outer circumferential surface... and a cylindrical second stopper arranged separate from a first inner circumferential surface of the main body
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A force sensor capable of preventing a strain body from being broken and improving reliability even when the stiffness of the strain body differs depending on axis directions is provided. In a force sensor 10 according to one embodiment, a main body 11 is cylindrical. A cylindrical movable body 12 is movable with respect to the main body and includes at least three circular openings 13 in the outer circumference thereof. A strain body 16 is fixed to the main body and the movable body and is deformable according to the movement of the movable body. Strain sensors 16a are provided on the strain body. A first stopper 14 is arranged inside each of the openings and includes a first outer circumferential surface including a first outer diameter less than a diameter of the opening. A cylindrical second stopper 24 is arranged separate from a first inner circumferential surface of the main body by a first distance and includes a second outer circumferential surface of a second outer diameter less than a diameter of the first inner circumferential surface.