Torque Limiting Tolerance Ring Disengagement Mechanism
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Solution Overview
Problem
Tolerance rings used in torque transmission applications face challenges in managing excessive torque, leading to potential damage due to friction and heat generation when one component seizes, as they lack a mechanism to disengage and prevent permanent damage.
Innovation Solution
A torque limiting tolerance ring with radially extending projections that can contract or expand to disengage from the shaft and collar, allowing for free rotation and reducing friction and heat generation by moving to a disengaged configuration when a threshold torque is exceeded, thereby preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a tolerance ring provides an interference fit to transmit torque, then torque transmission capability is improved, but risk of damage from excessive torque and heat generation increases
Solution Approach 1:
The tolerance ring incorporates a dynamic disengagement mechanism where the interference fit can be temporarily released when excessive torque is detected. The ring moves from an engaged state (protrusions compressed between shaft and collar) to a disengaged state (protrusions relieved from compression), allowing the system to adapt to varying torque conditions and prevent damage from overload while maintaining power transmission during normal operation.
2Reliability
If a tolerance ring maintains constant interference fit, then torque transmission is reliable, but friction and heat generation increase when one component seizes
Solution Approach 1:
The tolerance ring transitions from a static interference fit to a dynamic system that can disengage when abnormal conditions occur. When one component (shaft or collar) ceases rotation, the protrusions are relieved from compression, allowing the ring to move axially and disengage, thereby eliminating continuous friction and heat generation while maintaining reliable torque transmission during normal operation.
Solution Approach 2:
The tolerance ring enables the system to skip through abnormal conditions by temporarily disengaging when excessive friction or heat is detected. This allows the ring to rush through the harmful state by releasing the interference fit, preventing permanent damage, and then re-engage when normal operating conditions are restored.
3Power
If protrusions are compressed to provide interference fit, then torque transmission is improved, but mechanism to disengage and prevent damage is lacking
Solution Approach 1:
The tolerance ring employs a self-service disengagement mechanism where the protrusions themselves serve dual functions: transmitting torque when compressed and enabling disengagement when relieved from compression. The axial movement capability of the ring allows it to automatically disengage from the interference fit without requiring external control systems, maintaining simplicity while providing the necessary disengagement function to prevent damage.
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 torque limiting tolerance ring effectively reduces the risk of damage to components by allowing disengagement and minimizing residual torque, thus preventing excessive heat and friction, ensuring continued operation without permanent damage.
Implementation Method 1
A tolerance ring generally comprises a strip of resilient material, for example a metal such as spring steel
Implementation Method 2
Each protrusion can act as a spring and can exert a radial force against the shaft and the surface of the bore
Data Source
Figure 1
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AI summary
A torque limiting tolerance ring (106) is configured to be installed between an inner (102) and an outer (104) component. The torque limiting tolerance ring can include a generally cylindrical body (110) that can have a sidewall (112). The sidewall can include an unformed section (114) and a plurality of projections (116) can extend from the unformed section of the sidewall. The projections can be configured to engage the inner or the outer component. During use, the torque limiting tolerance ring can move from an engaged configuration, in which the inner component is statically coupled to the outer component, to a disengaged configuration, in which the inner component is disengaged from the outer component.