Linear Actuator Lead Screw Stopper Design
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Solution Overview
Problem
Conventional linear actuators face issues with lead screw breakage due to excessive torque loads, particularly at the pin hole area, which weakens the cross-sectional strength and poses safety risks during sudden impacts.
Innovation Solution
A stopper component set is integrated into the linear actuator design, comprising a first and second stopper block fastened together with a fastening member, which engages with the neck of the lead screw to provide axial stopping against thrust bearings, eliminating the need for a pin hole and enhancing the actuator's ability to handle greater axial thrust and impact loads without compromising structural strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a pin hole is created through the lead screw for pin insertion, then the lead screw can be stopped between thrust bearings during rotation, but the cross-sectional strength of the lead screw is reduced and it may break under excessive torque load
Solution Approach 1:
The invention extracts the stopping function from the lead screw body itself and relocates it to separate stopper blocks that are fastened to the lead screw. This removes the harmful pin hole from the lead screw while preserving the stopping function through alternative means (stopper blocks with stopping surfaces that contact thrust bearings).
Solution Approach 2:
The invention segments the stopping function into separate components (first and second stopper blocks) that are attached to the lead screw rather than embedding a pin through it. This segmentation allows the lead screw to maintain its structural integrity while the stopper blocks provide the necessary stopping surfaces against the thrust bearings.
2Force
If the lead screw bears excessively large torque load, then the actuator can handle greater axial thrust, but the sudden impact may cause the lead screw to break at the pin hole area
Solution Approach 1:
The invention removes the vulnerable pin hole from the lead screw design, eliminating the stress concentration point that causes breakage under impact loads. The stopping function is extracted and relocated to stopper blocks that do not compromise the lead screw's cross-sectional strength.
Solution Approach 2:
The stopper blocks are designed with stopping surfaces that engage the thrust bearings before excessive loads can transmit directly to any potential weak points on the lead screw. This prior engagement cushions and distributes the impact loads, preventing sudden breakage.
3Reliability
If a brake device is installed to stop the lead screw, then the telescopic tube can be prevented from dropping, but the device complexity increases
Solution Approach 1:
The stopper blocks serve multiple functions: they provide stopping surfaces against the thrust bearings to hold position, and they are integrated with the lead screw structure through fastening members. This multi-functionality eliminates the need for separate brake devices while maintaining position holding capability.
Solution Approach 2:
The stopper blocks and thrust bearings work together as a self-contained stopping mechanism that does not require external brake devices. The system uses its own structural components (stopper blocks, thrust bearings, and lead screw) to achieve position holding, eliminating the need for additional complexity.
Data Source
AI summary
A linear actuator includes an actuator body including a housing, a gear set mounted inside the housing, a drive unit mounted outside the housing for rotating the gear set, a transmission mechanism including a lead screw with an axial rod at one end thereof fastened to the gear set, a stopper component set fastened to a neck of the axial rod, two bearing housings mounted on the axial rod at two opposite ends of the neck and two thrust bearings respectively mounted in the bearing housings. When the lead screw is rotated, a first stopper block of the stopper component set is engaged with the neck of the axial rod to force the stopper component set against the thrust bearings, enabling the linear actuator to carry greater axial thrust or tensile load, increasing the high impact load strength of the linear actuator and ensuring overall structural stability and reliability.