Roller Screw Linear Actuator With Integrated Detent Locking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing linear actuators with compressive loads, such as those in power door opening systems, face inefficiencies due to complex mechanically gated locks and require significant mechanical components, which can be cumbersome and prone to failure under constant axial forces.
Innovation Solution
A linear actuator design featuring a screw shaft with a variable lead angle and rollers that interact with detents, allowing for a simple and non-complex locking mechanism using grooves that prevent axial movement, reducing the need for complex locks and optimizing force distribution based on load profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complex mechanically gated lock is used to secure the actuator output, then the locking reliability is improved, but the device complexity increases and the number of moving parts increases
Solution Approach 1:
The patent extracts the locking function from a separate complex mechanical lock and integrates it directly into the screw thread geometry through detents. This eliminates the need for a separate locking mechanism while maintaining the security function, thereby reducing device complexity while preserving locking reliability.
Solution Approach 2:
The locking function is merged with the drive mechanism by incorporating detents directly into the screw thread. The detents are formed as integral features of the screw shaft, combining the transmission and locking functions into a single integrated structure, reducing the number of components and simplifying the overall device.
2Reliability
If a complex mechanically gated lock is used, then the locking function is secured, but the quantity of components increases
Solution Approach 1:
The locking function is extracted from a separate mechanical lock assembly and embedded directly into the screw thread structure. This integration eliminates multiple discrete locking components and replaces them with geometric features formed directly on the screw shaft, significantly reducing the total quantity of components.
Solution Approach 2:
The screw shaft is designed to perform multiple functions: it provides the driving screw thread for actuation and simultaneously incorporates detents for locking. This multi-functionality eliminates the need for separate locking components, reducing the overall component count while maintaining both driving and locking capabilities.
3Reliability
If a complex mechanically gated lock is used, then the actuator can be secured at discrete positions, but the ease of operation deteriorates and maintenance becomes more difficult
Solution Approach 1:
The detent mechanism is designed to engage and disengage automatically based on the rotational position of the screw shaft. The system serves itself by using the natural rotation during actuation to automatically lock at discrete positions and unlock when needed, eliminating the need for separate locking operations and improving ease of use.
Solution Approach 2:
Instead of using a complex gate mechanism that requires manual operation, the patent inverts the approach by using the screw shaft's own rotation to automatically engage and disengage the detents. The locking and unlocking actions occur passively through the normal actuation motion, reversing the conventional approach and greatly simplifying operation.
4Loss of energy
If rollers are used to reduce friction, then the efficiency is improved, but the complexity of the locking mechanism increases
Solution Approach 1:
The locking function is merged with the roller support structure. The detents are integrated into the screw thread geometry and work in conjunction with the rollers, combining the friction-reducing roller mechanism with the locking function in a unified design that does not increase overall complexity.
Solution Approach 2:
The locking function is extracted from a separate complex mechanism and embedded into the screw thread-detent-roller interaction. This integration allows the locking capability to be achieved through the existing roller support structure without adding separate locking components, maintaining simplicity while reducing friction.
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 design provides a robust and efficient locking mechanism that minimizes mechanical complexity, adapts to varying compressive loads, and reduces the requirement for complex lock mechanisms, enhancing reliability and operational efficiency in systems like power door opening systems.
Implementation Method 1
The plurality of rollers each comprise a cylindrical surface configured to roll along one or more flanks of the screw thread, such that rotation of the screw shaft causes the rollers to roll along the flank(s) so that the nut translates in an axial direction along the screw shaft
Implementation Method 2
The screw thread comprises one or more detents, each configured to cooperate with one of the plurality of rollers to lock the nut in one or more axial positions. Each detent may be provided in the form of a groove configured to receive one of the plurality of rollers
Data Source
AI summary
A linear actuator includes a screw shaft comprising a screw thread and having a longitudinal axis A, a nut movable along the screw shaft from a retracted position to an extended position, and a plurality of rollers movable with the nut. Each roller includes a cylindrical surface configured to roll along one or more flanks of the screw thread, such that rotation of the screw shaft causes the rollers to roll along the flank(s) so that the nut translates in an axial direction along the screw shaft. The screw thread has a variable lead angle. The actuator can be part of a power door opening system of an aircraft.