Linear Actuator Static Stress Support Mechanism
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Solution Overview
Problem
Conventional electromechanical linear actuators with ball screw mechanisms are prone to degradation under static stresses, as the balls tend to bear strongly against the rolling track, causing damage due to concentrated stress points.
Innovation Solution
Incorporating a support means with a cylindrical shoe having a helical thread that rests on the rolling track along a contact line, and a control mechanism with an elastic prestressing element to maintain an inactive position until an axial stress threshold is exceeded, allowing the support to engage and distribute stress along a line rather than at point contacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the actuator uses balls in a ball screw mechanism for normal operation, then the actuator achieves smooth motion and reduced friction, but under static stresses the balls bear strongly against the rolling track causing degradation and damage
Solution Approach 1:
A support means is introduced as an intermediary element between the balls and the rolling track. This support means carries the rolling track and distributes the static stress away from the balls, preventing the balls from bearing strongly against the track during static loading conditions while allowing normal ball operation during dynamic actuation
Solution Approach 2:
The support means is designed to be movable relative to the outer tubular body, allowing it to dynamically engage and disengage based on loading conditions. During normal operation, the balls operate freely, but under static stress the support means engages to provide additional承载 capacity and protect the rolling track
2Object-affected harmful factors
If the actuator is designed to handle static stresses with enhanced support, then the rolling track is protected from degradation, but the device complexity increases due to additional control means
Solution Approach 1:
The support means is equipped with control means that enable it to automatically engage and disengage based on the actual loading conditions on the actuator. The system self-regulates without external control, engaging the support means when static stress is detected and disengaging during normal operation, thereby protecting the rolling track while maintaining 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 reduces stress concentration on the rolling track, minimizing damage and enabling the actuator to handle static stresses without hindering normal operation, while maintaining ease of installation and replacement.
Implementation Method 1
at least one means for exerting a prestressing on such a nut, this control means being designed, on the one hand, to maintain such a support means in an inactive support position
Data Source
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AI summary
The invention relates to a linear actuator (1) comprising: - an outer tubular body (2) having a helical rolling track (20); - an internal tubular body (3) with an engine (40) rotatable around a shaft (41) that is coaxial to the tubular bodies (2; 3); - at least one nut (42) having at least one helical rolling path (420) and a reflow area (421) mounted on said shaft (41); - and ball bearings (44) placed between a rolling path (420) of at least one nut (42) and a rolling track (20) of the outer tubular body (2), as well as in the reflow area (421) of such a nut (42). Said actuator (1) is characterized in that it comprises at least one means (5) for bearing against a rolling track (20) of the outer tubular body (2) along at least one line of contact, and at least one means (6) for controlling said bearing means (5).