Fluid-Filled Vibration Damping Device Cover Attachment
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Solution Overview
Problem
Existing fluid-filled vibration damping devices face challenges in ensuring reliable and enduring protection of flexible rubber films, particularly in automotive engine mounts, due to issues with the attachment of cover members which can lead to rattling, detachment, and difficulty in assembly, especially under radiant heat or hot fumes.
Innovation Solution
A fluid-filled vibration damping device with a cover member featuring annular fastening fittings bonded to the flexible rubber film, catch pieces extending circumferentially, and a rubber sheath layer, allowing for secure attachment and prevention of rattling through axial compression, facilitating easier assembly and maintaining protection of the flexible rubber film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If the flexible rubber film is made thin to ensure adequate volume change of the equilibrium chamber, then the volume change capability is improved, but the film becomes vulnerable to damage from contact with foreign matter
Solution Approach 1:
A cover member is introduced as an intermediary component between the external environment and the flexible rubber film. The cover member includes a catch portion that engages with a bulging portion on the film, creating a protective barrier that prevents foreign matter from contacting the thin film while allowing the film to maintain its thin construction for adequate volume change
2Strength
If the catch portion is made of hard material to provide secure engagement, then the engagement strength is improved, but the assembly becomes difficult due to lack of deformability
Solution Approach 1:
The material parameter of the catch portion is changed from hard material to rubber material, which provides adequate engagement strength through elastic deformation during assembly. The rubber material allows the catch portion to deform and surmount the bulging portion during assembly, then provides secure engagement through elastic recovery, resolving both the strength and ease of assembly requirements
3Ease of operation
If the bulging portion is made large to facilitate catch portion engagement, then the ease of assembly is improved, but the cover member becomes prone to detachment and rattling
Solution Approach 1:
The engagement structure is designed with localized features: the catch portion has a specific hook-shaped geometry with a catching surface, and the bulging portion has a corresponding shape with a groove. This localized geometric matching provides stable engagement that prevents detachment and rattling while maintaining ease of assembly through the deformable rubber material
4Device complexity
If the cover member is attached directly to the flexible rubber film without additional fastening, then the device complexity is reduced, but the attachment becomes unreliable under heat and vibration
Solution Approach 1:
The bulging portion is pre-formed on the flexible rubber film during manufacturing, creating a built-in engagement feature that protrudes from the film surface. This preliminary formation of the engagement feature allows the cover member to be securely attached through simple engagement of the catch portion with the pre-formed bulging portion, providing reliable attachment under heat and vibration without adding complex fastening 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 provides a stable and reliable attachment of the cover member, preventing rattling and detachment, while simplifying the assembly process and ensuring consistent protection of the flexible rubber film, even under adverse conditions.
Implementation Method 1
vibration damping action is produced on the basis of flow effects, such as the resonance effect, of fluid flowing through the orifice passage
Implementation Method 2
a main rubber elastic body linking the first mounting member and the second mounting member to one another in an elastic manner
Data Source
Figure 1
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AI summary
A fluid filled type vibration damping device (10) wherein an annular fastening fitting (54), to which an outside peripheral edge portion of a flexible rubber film (52) has been bonded by vulcanization, includes a rubber sheath layer (60) integrally formed with the flexible rubber film (52) over an outside face at an inner peripheral edge portion of the annular fastening fitting (54). A cover member (94) is attached covering the flexible rubber film (52) from an outside. The cover member (94) including contacting projections (108) provided to the cover member (94) in a part thereof that contacts the rubber sheath layer (60), and catch pieces (96) extending towards a second mounting member (14) disposed at multiple locations along a circumference thereof. With the catch pieces (96) engaging a projecting catch portion (80), the contacting projection (108) is pressed in the axial direction against the rubber sheath layer (60).