Gear Assembly Backlash Reduction via Passive Retardation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing rotational gear systems in spacecraft face challenges with accurate incremental movement due to backlash, which leads to positional errors and unresponsiveness, especially in applications requiring precise deployment and attitude control.
Innovation Solution
A rotatable gear assembly comprising a load gear engaged with a drive gear and an auxiliary gear, where the drive gear is coupled to a stepper motor for incremental rotation, and the auxiliary gear is coupled to a passive retardation device, such as a stepper motor with detent torque, to resist rotation and reduce backlash effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a standard gear system is used for rotational control, then the structure is simple, but backlash causes positional errors and unresponsiveness
Solution Approach 1:
The patent applies preliminary anti-action by introducing a passive retardation device that continuously applies a retarding torque to the load gear in the direction opposite to the drive gear's rotation. This pre-counters the backlash effect before it can cause significant positional error, ensuring the load gear remains firmly engaged with the drive gear teeth throughout the rotational movement.
Solution Approach 2:
The patent introduces a passive retardation device as an intermediary element between the drive gear and the load gear. This intermediary component (which may be a separate brake mechanism or a damping element) mediates the interaction between the driving and loaded components, eliminating the direct backlash problem by maintaining constant tooth engagement through applied retarding torque.
2Measurement precision
If a passive retardation device is added to reduce backlash, then positioning accuracy improves, but device complexity increases
Solution Approach 1:
The patent merges the passive retardation function with existing components in the gear system. Rather than adding a completely separate active control system, the retardation device is integrated into the gear train, possibly combining braking, damping, or friction elements with the gear structure itself, thereby reducing overall system complexity while achieving backlash elimination.
Solution Approach 2:
The passive retardation device operates autonomously without requiring external power or active control. It automatically provides retarding torque based on the direction of drive gear rotation, using passive mechanical elements such as friction brakes, viscous dampers, or elastic elements that self-regulate their retarding force throughout the operational range.
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 solution provides precise and responsive rotational control by maintaining tooth engagement, reducing backlash, and improving holding torque, ensuring accurate positional displacement and enhanced system responsiveness.
Implementation Method 1
the detent torque is provided by magnetic attraction between the at least one stepper rotor pole and at least one stepper stator pole when the stepper motor is unpowered
Implementation Method 2
the teeth of the drive gear and load gear abutting to exert a force on the load gear in one direction
Implementation Method 3
the teeth of the auxiliary gear and the load gear abutting to exert a force on the load gear in an opposite direction
Data Source
AI summary
The invention relates to a gear assembly (10) for use in a space craft for control of a moveable component thereof. The assembly comprises a load gear (11) in engagement with a drive gear (12) and an auxiliary gear (13). The drive gear (12) is coupled to a drive motor (14) so as to drive the load gear (11) in a first rotational direction. The auxiliary gear (13) is coupled to a retardation device (15) that is configured to passively resist the load gear (11) from rotating in the first rotational direction.