One-Way No-Back Clutch With Bearing for Reverse Torque Resistance
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Solution Overview
Problem
Existing no-back clutches, which rely on pawl and ratchet mechanisms, face inefficiencies in resisting back-driving torques due to compressive loads, particularly in applications like electric powered nacelle door opening systems, where they can lead to increased component count, weight, and cost.
Innovation Solution
A one-way clutch design utilizing a sprag clutch with a bearing, such as a thrust, needle roller, or ball bearing, is employed to manage compressive loads, allowing free-wheeling during forward rotation and jamming during reverse rotation, thereby inhibiting reverse torque transmission through a friction plate mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pawl and ratchet mechanism is used in a no-back clutch, then reverse rotation resistance is achieved, but device complexity and component count increase
Solution Approach 1:
The patent extracts and eliminates the pawl and ratchet mechanism from the no-back clutch design, replacing it with a simpler one-way clutch assembly that maintains the essential function of preventing reverse rotation while reducing overall component count and device complexity
Solution Approach 2:
The one-way clutch assembly performs multiple functions: it prevents reverse rotation, manages compressive loads through the bearing, and enables free-wheeling during forward rotation, thereby replacing what would traditionally require separate pawl-ratchet and bearing components
2Reliability
If a pawl and ratchet mechanism is used in a no-back clutch, then reverse rotation resistance is achieved, but weight increases
Solution Approach 1:
The patent removes the heavy pawl and ratchet components from the clutch assembly, replacing them with a lighter one-way clutch mechanism that achieves the same reverse rotation resistance function with reduced weight
Solution Approach 2:
The patent changes the fundamental operating parameters of the clutch mechanism by transitioning from a friction-based pawl-ratchet system to a one-way clutch system with a bearing, which reduces weight while maintaining the necessary load-bearing capacity and reverse rotation prevention
3Reliability
If a pawl and ratchet mechanism is used in a no-back clutch, then reverse rotation resistance is achieved, but manufacturing cost increases
Solution Approach 1:
The patent extracts the costly pawl and ratchet mechanism from the design and replaces it with a more economical one-way clutch assembly that achieves the same functional requirements at lower manufacturing cost
Solution Approach 2:
The patent employs a one-way clutch mechanism that uses simpler, more cost-effective components such as standard bearings and friction plates instead of precision-machined pawl and ratchet teeth, reducing manufacturing complexity and cost
4Device complexity
If a one-way clutch with bearing is used, then device complexity is reduced, but compressive load management capability must be maintained
Solution Approach 1:
The bearing in the one-way clutch assembly is selected to perform dual functions: it supports the compressive loads generated during operation and enables the free-wheeling rotation during forward motion, thereby maintaining load management capability while reducing overall device complexity
Solution Approach 2:
The bearing acts as an intermediary element that mediates between the one-way clutch portion and the friction plate, managing compressive loads and enabling smooth rotation while the one-way clutch portion handles the reverse rotation prevention function
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 configuration results in a compact, lightweight, and cost-effective solution that effectively resists reverse rotation, reducing the number of components and operational complexity.
Implementation Method 1
a bearing (40) disposed such that a compressive load path is formed from the first shaft, through the bearing and the outer diameter portion and to the friction plate and the second shaft
Implementation Method 2
a friction plate (46) affixed to the second shaft... create a drag event on the friction plate that inhibits reverse rotation transmission to the second shaft
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
An actuator (101) is provided and includes first (110) and second (120) shafts, a friction plate (130) affixed to the second shaft, a one-way clutch (140) that includes an inner diameter portion (141) affixed to the first shaft, an outer diameter portion (142) and a one-way clutch portion (143) interposed between the inner and output diameter portions and a bearing (150). The bearing is disposed such that a compressive load path is formed from the first shaft, through the bearing and the outer diameter portion and to the friction plate and the second shaft. The one-way clutch portion is configured for free-wheeling during forward rotation of the first shaft that permits forward rotation transmission to the second shaft and for jamming during reverse rotation of the first shaft to create a drag event on the friction plate that inhibits reverse rotation transmission to the second shaft.