Epicyclic Gear Brake Mechanism for Low-Force Load Release
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Solution Overview
Problem
Existing gear systems require substantial force and energy to operate due to high frictional forces, leading to inefficiencies and the inability to easily release loads without applying force, particularly in applications where backdriving is undesirable.
Innovation Solution
A gear apparatus with an epicyclic planetary gear arrangement and a releasable brake mechanism that allows for selective release of the sun gear or ring gear, reducing the force required to reverse rotation and enabling backdriving by decoupling the brake mechanism, thereby reducing the operational force and allowing for efficient torque transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a self-locking gear set with low helix angle is used to prevent load dropping, then the load can be held without power, but the system efficiency becomes less than 35% and larger power sources are required
Solution Approach 1:
The patent uses a dynamically adjustable brake mechanism that can transition between engaged and disengaged states. The brake is engaged during normal operation to prevent backdriving, and can be selectively disengaged to allow controlled load lowering or emergency release. This dynamic control eliminates the need for continuously high-friction self-locking gears while maintaining reliability when needed.
Solution Approach 2:
The system changes the friction parameter dynamically through the brake mechanism. When the brake is engaged, high friction prevents backdriving; when disengaged, low friction allows efficient operation and controlled movement. This parameter change enables the system to achieve both high reliability and good efficiency at different operational states, avoiding the permanently inefficient self-locking gear approach.
2Reliability
If a self-locking gear set is used to prevent backdriving, then the load does not drop when power is removed, but the system cannot allow the load to be dropped without force applied to the input
Solution Approach 1:
The brake mechanism serves as an intermediary between the gear set and the load. It provides controlled engagement and disengagement capability that direct self-locking gears cannot offer. The brake can be actuated by a separate control system (hydraulic, pneumatic, or electric), allowing easy and controlled load release without requiring substantial force on the input shaft, thus improving ease of operation while maintaining reliability.
3Reliability
If existing anti-backdrive devices use pins in larger holes with transfer blocks/brakes, then forward driving torque is allowed, but the system size becomes large and requires substantial energy to actuate
Solution Approach 1:
The patent extracts the backdrive prevention function from a complex mechanical transfer block/pin system and implements it through a simpler brake mechanism applied directly to the gear set. This eliminates the need for large pins and transfer blocks, reducing system size and complexity while maintaining effective backdrive prevention through the brake's friction engagement.
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 gear apparatus significantly reduces the force needed to control and reverse the rotation of large loads, enhancing efficiency and allowing for easy release of loads without substantial force application, while preventing backdriving when desired.
Implementation Method 1
the brake mechanism is arranged to prevent movement of the selectably releasable member when the input member and the output member move
Implementation Method 2
a gear apparatus with an epicyclic planetary gear arrangement and a releasable brake mechanism that allows for selective release of the sun gear or ring gear
Implementation Method 3
reducing the force required to reverse rotation and enabling backdriving by decoupling the brake mechanism
Data Source
AI summary
A gear apparatus for controlling movement of an output by an input coupled to a power source. The apparatus an input member coupled to the input, an output member coupled to the output and the input member so that movement of the input member causes movement of the output, a selectably releasable member coupled to the input member and the output member, wherein the selectably releasable member remains in a fixed position while the input member and the output member move, and a releasable member brake mechanism coupled to the selectably releasable member, wherein the releasable member brake mechanism is arranged to prevent movement of the selectably releasable member when the input member and the output member move and to allow back driving of the selectably releasable member.