Bi-directional Overrunning Clutch Split Roll Cage
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Solution Overview
Problem
Current bi-directional overrunning clutches for primary drive axles in machinery like snowblowers and all-terrain vehicles are complex and unreliable, with potential issues of reverse engagement that can cause unintended torque transmission, akin to solid shaft drives, compromising cornering ability and wheel slippage.
Innovation Solution
A bi-directional overrunning clutch with a split roll cage configuration, featuring a housing with inner cam surfaces, coaxially aligned hubs, roller assemblies, friction disk mechanisms, and a roll cage coupler with radially extending teeth, which prevents reverse engagement by allowing indexing of one roll cage relative to the other, ensuring proper torque distribution and preventing rollers from engaging with the wrong cam surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a bi-directional overrunning clutch is used to control torque transmission, then cornering ability and wheel slippage are improved, but the device complexity increases
Solution Approach 1:
The clutch system is divided into two separate roller assemblies, each with its own roll cage, hubs, and friction disk mechanisms. This segmentation allows independent control of torque transmission to left and right drive shafts, enabling differential rotation for improved cornering ability while maintaining modular complexity
Solution Approach 2:
The invention introduces a second degree of freedom by allowing the two roller assemblies to rotate in opposite directions relative to each other. This dimensional change from single-axis to dual-axis independent rotation enables the clutch to handle bidirectional torque transmission, improving adaptability for complex driving conditions
2Power
If rollers are allowed to engage with cam surfaces in both directions, then torque transmission is maintained, but reverse engagement causes unintended torque transmission compromising reliability
Solution Approach 1:
The roll cages are designed with asymmetric tooth configurations that allow rollers to engage cam surfaces in one direction while preventing engagement in the opposite direction. This asymmetric design ensures torque transmission occurs only when intended, eliminating reverse engagement issues and improving reliability
Solution Approach 2:
Friction disk mechanisms act as intermediary elements between the rollers and hubs. These friction disks control the engagement and disengagement of rollers with cam surfaces, allowing precise management of torque transmission and preventing unintended reverse engagement
3Device complexity
If a solid shaft drive is used, then the structure is simple, but cornering ability and wheel slippage control are compromised
Solution Approach 1:
The clutch system replaces the static solid shaft connection with dynamic roller assemblies that can independently adjust torque distribution. The rollers can engage or disengage from cam surfaces based on rotational direction and speed, providing dynamic control of wheel slippage and cornering ability
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 a simpler, more reliable clutch system that maintains positive driving engagement while allowing overrunning, preventing reverse engagement issues and enhancing cornering ability and reducing wheel slippage, thus improving the performance of wheeled machines.
Implementation Method 1
a spring compressed for biasing the friction plate into frictional contact with the contact surface of the hub
Implementation Method 2
a spring compressed for biasing the friction plate into frictional contact with the contact surface of the hub
Implementation Method 3
the rollers being spaced about an associated hub and adapted to wedgingly engage between the hub and the inner cam surface
Implementation Method 4
the inner cam surface has a forward cam surface and a reverse cam surface, such that when the housing is being driven with respect to at least one of the hubs, the rollers wedgingly engage between the forward cam surface and the at least one hub
Data Source
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AI summary
A bi-directional overrunning clutch includes a housing and a pair of hubs substantially coaxially aligned within the housing. A pair of roll cages position a plurality of rollers between each hub and an inner cam surface of the housing. The rollers are positioned to wedge between the hub and the inner cam surface when one of the hub and the housing is rotated with respect to the other. End cap's are attached to the housing adjacent to the hubs. A friction disk mechanism includes a friction plate rotating in combination with each the roll cage and a spring compressed between the end cap and the roil cage for biasing the friction member into frictional contact with the hub. An intermittent coupler is located between each roll cage and configured to engage the roll cages so as to permit indexing of one roll cage relative to the other.