Uncoupling Pulley with Resilient Ring Gear for Shock Absorption
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Solution Overview
Problem
Existing uncoupling pulleys experience repeated shocks during acceleration and deceleration, leading to potential loosening of the power-transmission elements, particularly in engine vehicles with high acceleration and deceleration cycles, which can reduce the pulley's lifespan.
Innovation Solution
The proposed uncoupling pulley design features a wheel rim with a ring gear that includes a resiliently deformable element, such as a torsion spring, and cylindrical skirts that allow for relative rotation, providing a more gradual torque transfer and reducing the risk of shocks by using a unidirectional clutch or freewheel mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the uncoupling pulley uses a rigid connection between wheel rim and bell with torsion spring, then torque transfer is efficient, but repeated shocks occur during acceleration and deceleration
Solution Approach 1:
The patent applies the dynamics principle by making the connection between the wheel rim and bell dynamic rather than rigid. The uncoupling mechanism allows the bell to rotate independently relative to the wheel rim during high acceleration and deceleration events, absorbing shock loads while maintaining torque transfer during normal operation. This dynamic behavior resolves the contradiction by adapting the connection stiffness based on operating conditions.
Solution Approach 2:
The patent implements beforehand cushioning through the uncoupling mechanism that anticipates and prepares for shock loads during engine starting and deceleration. The mechanism allows controlled slippage or disengagement before extreme shock loads can damage the power transmission elements, thereby cushioning the system against repeated shocks while maintaining efficient torque transfer during normal operation.
2Reliability
If the uncoupling pulley allows relative rotation between wheel rim and bell, then shock-induced stress is reduced, but torque transfer efficiency decreases
Solution Approach 1:
The uncoupling mechanism dynamically adjusts the connection between wheel rim and bell based on load conditions. During normal torque transfer, the connection remains engaged for efficient power transmission. During high acceleration and deceleration, the mechanism allows controlled relative rotation to absorb shock loads, thus maintaining reliability without permanently compromising torque transfer efficiency.
Solution Approach 2:
The patent changes the operational parameters of the connection between wheel rim and bell. The uncoupling mechanism modifies the engagement state based on operational conditions - fully engaged during normal torque transfer for maximum efficiency, and partially disengaged or allowing relative rotation during shock events to reduce stress and maintain reliability.
3Stability of the object's composition
If the uncoupling pulley uses bell stops to limit rotation angle, then rotational limits are defined, but repeated shocks occur at maximum angular displacement
Solution Approach 1:
The patent applies beforehand cushioning by designing the uncoupling mechanism to gradually reduce torque transmission as the bell approaches maximum angular displacement, rather than allowing abrupt stopping against hard stops. The mechanism prepares for the end of rotation range by progressively disengaging or softening the connection, thereby cushioning against shock loads at the limits of rotation while maintaining stable angle control.
Solution Approach 2:
The uncoupling mechanism acts as an intermediary between the wheel rim and bell, mediating the torque transfer and angular displacement. Rather than allowing direct rigid connection with hard stops, the uncoupling mechanism provides a compliant interface that can accommodate angular limits while reducing shock transmission, thus protecting the system from repeated shocks at maximum displacement.
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 design enhances the pulley's lifespan by minimizing shock-induced stress and maintaining efficient torque transfer, reducing wear and tear, and preventing loosening of the power-transmission elements.
Implementation Method 1
a resiliently deformable element, for example a torsion spring centered on the hub
Implementation Method 2
providing a more gradual torque transfer and reducing the risk of shocks by using a unidirectional clutch or freewheel mechanism
Data Source
AI summary
An uncoupling pulley includes a wheel rim including a first area, intended for receiving a belt connecting the wheel rim to a first power-transmission element, and a second area extending from the first area; a hub rigidly connected to a second power-transmission element; a ring gear including a first portion located under the second area and a second portion presented in the shape of a resilient cylindrical skirt extending, from the first portion, along the longitudinal axis, the cylindrical skirt of the ring gear including a plurality of longitudinal slots and consequently a plurality of portions separated from each other by one of the slots, the ring gear being capable of rotating relative to the wheel rim; and a device for driving the ring gear; and a resiliently deformable element, one end of which is attached to the hub and another end of which is attached to the ring gear.