Rolling Diaphragm Bump Stop for Vehicle Closure Damping
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Solution Overview
Problem
Existing bump stop devices fail to effectively reduce vibration noise and provide adequate protection against slam damage during vehicle operation, as they cannot account for minor displacements between closing parts and have rigid rubber heads that minimize protection.
Innovation Solution
A bump stop with a rolling diaphragm and adjustable shaft, where the diaphragm rolls to take up tolerances between the vehicle body and closure, providing a resilient contact that reduces vibration noise and offers improved protection by maintaining a constant reaction force against the closure, even after initial adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a rigid rubber head is used in the bump stop, then metal-on-metal contact is prevented, but vibration noise is not effectively reduced and slam damage protection is minimized
Solution Approach 1:
The patent applies the dynamics principle by replacing the rigid rubber head with a resilient contact portion that can dynamically adjust to minor displacements between closing parts. The resilient contact portion deforms elastically under load, allowing the system to adapt to varying clearance conditions while maintaining continuous contact. This dynamic behavior enables effective vibration damping through energy absorption during each contact cycle, while the progressive stiffness characteristic provides increasing resistance force to protect against slam damage.
Solution Approach 2:
The patent implements parameter changes by designing the resilient contact portion with progressive stiffness characteristics. The force-displacement relationship is non-linear, where the stiffness increases as the compression distance increases. During normal operation with minor displacements, the contact portion remains relatively compliant to reduce vibration noise. During slam events with large displacements, the progressive stiffening provides increasing resistance force to protect against damage, thus changing the mechanical parameter of stiffness dynamically based on the magnitude of displacement.
2Adaptability or versatility
If a fixed-height bump stop is used, then installation is simple, but it cannot account for minor displacements between closing parts causing drumming noise
Solution Approach 1:
The patent applies the self-service principle by enabling the bump stop to automatically adjust its effective height through the resilient contact portion. During the first closing of the closure, the resilient contact portion compresses and sets the initial shaft extension height based on the actual clearance between body and closure. The height adjustment means allows manual intervention only when needed, after which the system serves itself by maintaining appropriate contact pressure through the resilient element's elastic properties, eliminating the need for complex continuous adjustment mechanisms.
Solution Approach 2:
The patent implements preliminary action by providing a height adjustment means that enables initial setting of the shaft extension height before normal operation begins. This preliminary adjustment allows the bump stop to be adapted to the specific clearance conditions of each vehicle during installation or maintenance. Once set, the resilient contact portion maintains the appropriate contact pressure automatically, combining the benefits of initial adaptability with simplified ongoing operation.
3Adaptability or versatility
If the shaft extension height is fixed after initial adjustment, then the bump stop is stable, but it cannot accommodate thermal expansion or wear-induced clearance changes
Solution Approach 1:
The patent applies dynamics by using the resilient contact portion to dynamically compensate for clearance changes caused by thermal expansion and wear. The elastic properties of the resilient material allow it to deform and maintain contact pressure despite changes in the gap between body and closure. This dynamic adaptation ensures continuous protection and vibration damping without requiring the shaft height to be fixed, as the resilient element absorbs the dimensional changes through elastic deformation.
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 reduces vibration noise and provides enhanced protection against slam damage by allowing the diaphragm to roll and absorb minor displacements, ensuring a progressive damping action and maintaining a constant resistance force against the closure, thus preventing damage.
Implementation Method 1
a diaphragm is arranged between the contact face and the outer wall, the diaphragm being arranged to be a rolling diaphragm in use
Implementation Method 2
the moveable element comprising a resilient contact portion arranged to contact the other of the body and the closure in use
Data Source
AI summary
Bump stop 10 for a vehicle closure (110, Fig. 1) progressively damps movement of closure 110 by distortion of rolling diaphragm 23 and of wall 25. Stop 10 may have a shaft 13 whose extension from housing 11 is height adjustable by ratchet teeth (16, 17, Fig. 1); and locked by a key 19. The force to adjust the ratchet teeth is greater than the force to reduce gap C 0 (Fig. 3) between head 18 and shaft 13, so that head 18 and diaphragm 23 spring back after height adjustment, to contact closure 110 and to dampen its vibrations while driving. If gap C 0 is closed, e.g. under slam conditions, the bump stop stiffens rapidly to brake closure movement. Shaft 13 may comprise an upstanding ring (26, Fig. 3) under head 18; which may comprise rings and ribs (27 and 28, Fig. 5).