Teeter-Totter Clutch Strut Geometry Against Shock Deployment
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Solution Overview
Problem
Unintended deployment of locking members in clutch assemblies due to shock loads can cause undesirable operation and damage, often resulting from failed solenoid or strut springs allowing the plunger or strut to move freely during sudden accelerations or decelerations.
Innovation Solution
A torque locking mechanism featuring a teeter-totter strut with a center of mass positioned behind the pivot point and enhanced pocket geometry, including ears and a recessed surface, prevents unintended deployment by utilizing the strut return spring and geometric design to resist shock loads, ensuring the strut remains in a retracted position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solenoid spring fails or a strut spring fails, then the plunger or strut becomes free to move, but this results in unintended deployment of the strut during shock loads
Solution Approach 1:
The patent applies preliminary anti-action by designing the strut geometry and pivot positioning to create a negative moment arm that actively counteracts shock load forces before unintended deployment can occur. The center of mass is positioned to generate a restoring moment that opposes the deployment tendency during shock events, preventing the harmful effect before it manifests.
Solution Approach 2:
The patent employs the anti-weight principle by positioning the strut's center of mass to create a counterbalancing moment that offsets the effects of shock loads. The mass distribution is deliberately designed so that the gravitational and inertial forces generate a moment that opposes unintended deployment, effectively using the strut's own weight as a protective mechanism.
2Ease of operation
If the strut is designed to pivot freely for normal operation, then ease of operation is improved, but reliability under shock load conditions deteriorates due to unintended deployment
Solution Approach 1:
The patent applies local quality by creating different functional zones along the strut structure. The pivot area allows free movement for normal operation, while the center of mass positioning creates a localized moment arm that specifically counteracts shock loads. The geometric parameters (widths and lengths) are varied along the strut body to optimize the moment arm characteristics without restricting normal pivoting motion.
Solution Approach 2:
The patent employs asymmetry in the strut's cross-sectional dimensions, with the first width being greater than the second width, and the first length being different from the second length. This asymmetric geometry is deliberately designed to position the center of mass at a specific location that creates the negative moment arm effect, while maintaining the ability to pivot freely during normal operation.
3Reliability
If the center of mass is positioned to prevent unintended deployment during shock loads, then reliability is improved, but the structural complexity increases due to specific geometric requirements
Solution Approach 1:
The patent applies parameter changes by systematically varying the geometric parameters of the strut, including the first width, second width, first length, and second length, to achieve the desired center of mass positioning. These parameter adjustments are made within practical manufacturing ranges and create the necessary moment arm characteristics without requiring complex additional components or mechanisms.
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 effectively prevents strut deployment during shock loads by creating a negative moment about the pivot point, reducing the risk of damage and operational issues, and can be applied to various clutch assemblies, such as dynamic controllable clutches and mechanical diodes.
Implementation Method 1
utilizing the strut return spring and geometric design to resist shock loads
Implementation Method 2
A center of mass of the teeter-totter strut is configured so that when a shock load force acts on the teeter-totter strut, the teeter-totter strut is prevented from moving into the engaged position
Data Source
AI summary
A clutch assembly includes a pocket plate, and a teeter-totter strut retained in a pocket plate pocket and pivotable to engaged and disengaged positions. A strut center of mass is configured so that when a shock load force acts on the strut, the strut is prevented from moving into the engaged position. A torque locking mechanism includes a strut housing having a strut pocket, a strut having ears, and a cover. The strut has a center of mass between the ears and a portion of the pocket. A clutch strut includes ears extending transversely from a body. A first portion of the body between the ears and an abutment surface has a first length and width, and a second portion of the body between the ears and a load bearing surface has a second length longer than the first length and a second width narrower than the first width.