Actuator Output Lever Root Corner Curvature
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing actuators face stress concentration issues at the root of the biting parts when high torque is applied, leading to potential damage due to shearing forces, particularly in the swaging process where the output shaft bites into semicircular cutouts of the output lever.
Innovation Solution
The actuator design includes an output shaft with a large diameter portion, a cylindrical portion, and an enlarged diameter portion, where the output lever has a cylindrical hole and radially outwardly recessed cutouts, with the root corner shaped as a convex curved surface, reducing stress concentration and enhancing shear strength by conforming the biting part's root to a concave curved surface, and ensuring a strong swaged engagement through both engaging and frictional forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the output shaft bites into semicircular cutouts through the swaging process to transmit torque, then the torque transmission capability is improved, but stress concentration occurs at the root of each biting part leading to potential damage
Solution Approach 1:
The root corner of the cutout is formed with a convex curved surface instead of a sharp corner, and the biting part root is formed with a concave curved surface to match. This curvature design distributes the stress more evenly across the biting interface, preventing stress concentration at sharp corners while maintaining effective torque transmission through the swaged engagement.
Solution Approach 2:
The cutout geometry is optimized locally at the root corner region by providing a convex curved surface, while the rest of the cutout maintains its semicircular form for torque transmission. The biting part also has a locally optimized concave curved root that conforms to the cutout's convex curve, creating a stress-distributing interface specifically where stress concentration would otherwise occur.
2Power
If a large torque acts on the output shaft, then the power transmission is improved, but the biting part of the output shaft is damaged by shearing force
Solution Approach 1:
The convex curved surface at the root corner of the cutout and the corresponding concave curved surface at the biting part root create a distributed stress interface that can withstand large torques without concentrating shear stresses at sharp corners, thereby preventing damage while maintaining high power transmission capability.
Solution Approach 2:
The curved surface geometry is designed in advance to cushion and distribute the high shear forces that will act on the biting part during operation. By pre-shaping the root corners with convex and concave curves, the design anticipates and mitigates the harmful effects of high torque loading before damage can occur.
Data Source
AI summary
An actuator includes an electric motor, an output shaft and an output lever. The output lever is fixed to one end portion of the output shaft, which is located at an outside of a housing. The output lever includes a cylindrical hole, through which a cylindrical portion of the output shaft is received, and a cutout, which is radially outwardly recessed from the cylindrical hole. A part of an inner wall surface of the cutout, which is connected to an inner wall surface of the cylindrical hole, is defined as a root corner. The root corner is shaped in a convex curved surface form in a view taken in an axial direction of the cylindrical hole.