Cam-Driven Aircraft Linear Drive for Zero Backlash Motion
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Solution Overview
Problem
Existing linear drive systems for aircraft components, such as high-lift devices and control surfaces, lack zero backlash, large gear reduction, self-locking ability, and efficient load transfer, which are crucial for reliable operation and reduced wear.
Innovation Solution
A track drive device with a rotatable cam member and engaging members that move in a wave-like pattern, allowing for sequential engagement and disengagement along a toothed rack, providing zero backlash and large gear reduction, and enabling self-locking and improved load transfer through a cam shaft and drive unit configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional linear drive systems are used, then the structure is simple, but zero backlash and large gear reduction cannot be achieved
Solution Approach 1:
The drive mechanism is divided into multiple drive units, each with its own cam member and engaging members. This segmentation allows each unit to independently contribute to the overall gear reduction while maintaining zero backlash through precise cam-controlled engagement, resolving the contradiction between achieving high precision and keeping the device simple.
Solution Approach 2:
The cam members are configured to dynamically control the engagement and disengagement of engaging members with the toothed rack. This dynamic control enables smooth transitions between engagement states, eliminating backlash while maintaining a relatively simple mechanical structure compared to traditional multi-stage gear systems.
2Reliability
If conventional linear drive systems are used, then the device complexity is low, but self-locking ability and load transfer efficiency are insufficient
Solution Approach 1:
The cam members are designed to automatically engage and disengage the engaging members with the toothed rack based on the rotational position of the cam. This self-service mechanism provides inherent self-locking capability without requiring additional locking devices or complex control systems, as the cam geometry itself controls the engagement state.
Solution Approach 2:
The functions of motion control, load transfer, and self-locking are merged into a single integrated cam-driven mechanism. The cam member simultaneously controls the engagement timing, distributes the load across multiple engaging members, and provides self-locking through its geometric design, eliminating the need for separate mechanisms for each function.
3Duration of action of moving object
If conventional linear drive systems are used, then the wear is high, but the gear reduction ratio is limited
Solution Approach 1:
Multiple drive units with cam members are arranged to provide continuous engagement with the toothed rack along its length. This continuous distribution of engagement points ensures that load is consistently transferred across multiple contact zones, reducing wear on individual teeth while maintaining a compact gear reduction mechanism.
Solution Approach 2:
Instead of achieving gear reduction through multiple sequential gear stages (one-dimensional approach), the invention uses multiple cam-driven engaging members distributed along the rack in the longitudinal dimension. This dimensional change allows for large cumulative gear reduction while distributing wear across multiple simultaneous contact points.
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 track drive device achieves zero backlash, large gear reduction, self-locking capability, and reduced wear by using a cam-driven engaging mechanism, enhancing the reliability and efficiency of aircraft component movement.
Implementation Method 1
a rotatable cam member having a control cam portion, the control cam portion being configured so as to, upon rotation of the cam member, sequentially move the engaging members between the fully engaged and fully disengaged positions so as to cause a linear motion of the track member relative to the drive device along the longitudinal direction
Data Source
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AI summary
In order to provide a track drive device (34) for an aircraft (10) that has zero backlash, a large gear reduction, the ability to self-lock, and a better load transfer and reduced wear, the invention proposes that the track drive device (34) drives a track member (36) through a drive device (46) that has at least one drive unit (48) that is arranged adjacent to the track member (36). Each drive unit (48) comprises a plurality of engaging members (50) that are driven by a cam shaft (26) or a cam gear such that the engaging members (50) are sequentially shifted in a wave-like pattern which results in the track member (36) being moved in a linear manner relative to the drive device (46) along a longitudinal direction.