Strut-Type Selectable Clutch Anti-Deployment Features
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Solution Overview
Problem
Automatic transmission systems face issues with unintended hydraulic deployment of struts in controllable one-way clutches due to excessive oil levels and fluid dynamics, leading to premature fatigue and loss of latching function.
Innovation Solution
Incorporating anti-deployment features such as elongated flow channels, cammed surfaces, and flow channels or 'spoilers' in the one-way clutch assembly to direct fluid flow and maintain the strut in its non-deployed position, reducing hydraulic forces and preventing unintended deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the strut is designed to be movable between deployed and non-deployed positions for lockup and freewheel modes, then the clutch provides controllable functional modes, but excessive oil levels and fluid dynamics cause unintended hydraulic deployment leading to premature fatigue failure
Solution Approach 1:
The patent applies preliminary anti-action by designing flow channels and cammed surfaces that preemptively counteract the hydraulic forces before they can cause unintended strut deployment. The flow channels are configured to direct fluid flow away from the strut tip, and the cammed surfaces are shaped to redirect hydraulic pressure, both acting in advance to prevent the harmful hydraulic deployment effect from occurring.
Solution Approach 2:
The patent converts the harmful hydraulic fluid pressure into a beneficial force by using cammed surfaces that redirect the fluid flow. The fluid pressure that would normally cause unintended deployment is instead channeled to apply force against the strut return spring, helping to maintain the strut in its intended position and actually reinforcing the desired operational mode.
2Ease of operation
If the strut return spring provides biasing force to maintain non-deployed position, then the strut can be reset after actuation, but hydraulic forces from excessive oil levels overcome the biasing force causing unintended deployment
Solution Approach 1:
The patent applies the anti-weight principle by using the strut return spring as a counterbalancing force against the hydraulic forces. The spring is calibrated to provide a biasing force that counteracts the hydraulic pressure from excessive oil levels, preventing the strut from being pushed into unintended deployment while maintaining the ability to reset after actuation.
Solution Approach 2:
The patent introduces flow channels and cammed surfaces as intermediary elements between the hydraulic fluid and the strut. These intermediaries modify the interaction by directing fluid flow away from the strut tip and redistributing hydraulic pressure, thereby reducing the direct force that would otherwise overcome the return spring biasing force.
3Power
If the strut is deployed to establish lockup mode, then torque transmission is achieved, but unintended deployment causes ratcheting against the inner race resulting in fatigue failure
Solution Approach 1:
The patent prevents the harmful ratcheting effect by implementing flow channels and cammed surfaces that preemptively counteract hydraulic forces before they can cause unintended deployment. By directing fluid flow away from the strut tip and redistributing pressure, the design eliminates the conditions that lead to repeated unintended deployment and subsequent fatigue failure.
Solution Approach 2:
The patent applies beforehand cushioning by using the return spring to continuously bias the strut toward the non-deployed position, creating a protective force that prevents unintended deployment. This cushioning effect is reinforced by the flow channels and cammed surfaces that work in advance to redirect hydraulic forces, protecting the strut system from fatigue-causing ratcheting before it can occur.
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 anti-deployment features effectively inhibit unintended strut deployment, enhancing the durability and reliability of the clutch system by reducing hydraulic forces and maintaining the strut in its non-deployed position, thus preventing premature fatigue and maintaining primary latching function.
Implementation Method 1
elongated flow channels, cammed surfaces, and flow channels or 'spoilers' in the one-way clutch assembly to direct fluid flow
Implementation Method 2
This pressure gradient, in combination with fluid dynamics associated with fluid flow around the clutch components, results in a force vector acting on an end portion of the strut
Implementation Method 3
the biasing force exerted on the strut by the strut return spring
Data Source
AI summary
A one-way clutch having an anti-deployment feature operable to counteract hydraulic forces acting on the strut so as to assist in maintaining the strut in a non-deployed position.