CV Joint Crash Collapse Structure for Propeller Shaft Safety
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Solution Overview
Problem
Conventional propeller shaft assemblies lack a mechanism to absorb crash forces effectively, leading to potential injury to passengers and damage to nearby vehicle components during collisions, as the propeller shafts tend to buckle and transmit harmful forces.
Innovation Solution
A constant velocity joint assembly with a crash collapse feature, featuring an inner and outer race, a cage, and torque transfer elements, where the crash collapse features allow the cage to radially collapse inward upon impact, enabling the first shaft to translate axially into the second shaft, thereby absorbing crash forces and preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional propeller shaft assemblies are used to transmit torque, then torque transmission is achieved, but the shafts buckle and penetrate the passenger compartment during crash conditions, causing injury and damage
Solution Approach 1:
The patent incorporates a cage collapse feature that is pre-designed to deform in a controlled manner during crash conditions. This collapse feature acts as a cushioning element that absorbs crash forces before they can be transmitted to the passenger compartment, thereby resolving the contradiction between maintaining structural integrity for torque transmission and preventing harmful force transmission during crashes.
Solution Approach 2:
The patent converts the harmful buckling and penetration behavior of conventional propeller shafts during crashes into a beneficial controlled collapse mechanism. The cage collapse feature is designed to deform predictably under crash loads, transforming the potentially harmful uncontrolled buckling into a beneficial force-absorbing event that protects passengers while still allowing torque transmission during normal operation.
2Strength
If the propeller shaft assembly is made more rigid to prevent buckling, then crash force absorption is reduced, but the shaft becomes more prone to transmitting harmful forces during collision
Solution Approach 1:
The patent applies dynamics by designing the cage collapse feature to transition from a rigid torque-transmitting structure during normal operation to a deformable energy-absorbing structure during crash conditions. The collapse feature remains rigid under normal torque loads to maintain shaft strength, but is designed to deform in a controlled manner when subjected to crash forces, thereby dynamically adapting its mechanical properties based on the operational state.
Solution Approach 2:
The patent utilizes parameter changes by designing the cage collapse feature with specific geometric parameters (such as wall thickness, radius, and structural configuration) that allow it to maintain rigidity under normal torque loads while enabling controlled deformation under crash loads. By carefully selecting these parameters, the system achieves both high strength during operation and effective energy absorption during crashes.
3Reliability
If the constant velocity joint is designed with traditional structural integrity, then torque transmission is reliable, but the joint cannot absorb crash forces without injuring passengers or damaging components
Solution Approach 1:
The patent applies segmentation by dividing the constant velocity joint into distinct functional zones: a rigid torque transmission zone that ensures reliable power transfer during normal operation, and a dedicated cage collapse zone that is designed to deform during crashes. This segmentation allows each zone to optimize its performance for its specific function, resolving the contradiction between maintaining structural integrity for torque transmission and enabling crash force absorption to protect passengers.
Data Source
AI summary
A constant velocity joint assembly with a crash collapse feature. The constant velocity joint assembly includes an inner race, an outer race, a cage and one or more torque transfer elements. The inner race is drivingly connected to a first shaft and the outer race is connected to a second shaft. Circumferentially extending along at least a portion of an inner surface of the outer race is one or more outer race torque transfer element grooves. One or more crash collapse features circumferentially extend radially inward from at least a portion of the inner surface of the outer race and are disposed directly adjacent to the one or more outer race torque transfer element grooves in the outer race. The one or more crash collapse features are disposed entirely between the one or more outer race torque transfer element grooves and do not extend axially beyond the grooves.