Composite Rolling Piston for Air Spring Bellows
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Solution Overview
Problem
Existing rolling pistons, particularly those made of glass fiber reinforced plastic, are prone to brittle failure and splintering when damaged, leading to safety risks due to sharp fragments and inefficiencies in internal volume utilization and manufacturing processes like friction welding.
Innovation Solution
A rolling piston constructed from a layered composite material of alternating plastic and elastomeric layers, where the elastomeric material acts as an intermediate layer to prevent fragmentation upon overload, and is designed with features like conical or stepped connections to enhance durability and sealing, using vulcanized rubber or adhesive layers for assembly and stress reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If glass fiber reinforced plastic is used for the rolling piston, then weight is reduced and manufacturing costs decrease, but the material becomes hard and brittle causing splintering upon damage
Solution Approach 1:
The patent uses glass fiber reinforced plastic (GRP) as a composite material to achieve weight reduction while maintaining structural integrity. The composite structure combines plastic matrix with glass fiber reinforcement, providing both light weight and resistance to brittle failure, thus resolving the contradiction between weight reduction and splintering prevention.
2Volume of moving object
If the internal volume is fully utilized to enlarge working space, then the risk of splinter acceleration increases due to internal pressure
Solution Approach 1:
The patent designs the piston wall thickness and structural geometry in advance to withstand internal pressure without failing. By pre-engineering adequate wall thickness and reinforcement, the piston can fully utilize its internal volume for working space while preventing catastrophic failure that would lead to splintering and acceleration by internal pressure.
3Ease of manufacture
If injection molding is used to manufacture plastic pistons, then manufacturing ease increases, but flow fronts create weak points in highly stressed zones
Solution Approach 1:
The patent applies local quality by reinforcing specific zones where flow fronts occur during injection molding. By adding localized reinforcement ribs or modifying the geometry at critical areas, the patent maintains the ease of injection molding while compensating for the weak points created by flow fronts in highly stressed zones.
4Ease of manufacture
If friction welding is used to connect two-part pistons, then assembly is achieved, but discontinuities in material parameters occur reducing reinforcing effect
Solution Approach 1:
The patent modifies the connection design between piston parts to avoid the material parameter discontinuities inherent in friction welding. By changing the connection parameters - such as using mechanical interlocking features, over-molding, or alternative joining methods - the patent maintains assembly capability while eliminating the weak weld seams that reduce the reinforcing effect of glass fibers.
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 prevents sharp-edged splintering, enhances load-bearing capacity, and ensures airtight connections, allowing full utilization of internal volume without the drawbacks of friction welding, while maintaining ease of manufacturing and assembly.
Implementation Method 1
the layer or intermediate layer made of elastomeric material is designed as an elastomer adhesive. For e.g. two concentrically arranged part-bodies made of fiber-reinforced plastic, the inner bulb and the outer bulb, between which an elastomeric adhesive layer is arranged, which firmly connects the two part-bodies to one another (glued), the security against brittle breaking of plastic parts is further increased. If one of the two partial bodies or both partial bodies break, the adhesive forces hold the fragments firmly on the surfaces of the elastomeric adhesive layer.
Implementation Method 2
the layer or intermediate layer made of elastomeric material contains a rubber layer, in particular a rubber layer vulcanized onto at least one piston part. Due to its elasticity, such a position allows stress reduction between the piston parts connected thereby
Implementation Method 3
The layer or intermediate layer made of elastomeric material contains a rubber layer, in particular a rubber layer vulcanized onto at least one piston part
Data Source
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AI summary
The invention relates to a rolling piston (1) for an air spring rolling bellows (2). A rolling piston (1) made of plastic for an air spring rolling bellows (2), which comprises at least two piston parts connected to one another, in particular comprising a substantially pot-shaped and rotationally symmetrical lower piston part (3) and an upper piston part (4) formed so as to be complementary thereto, wherein the rolling piston is made of a composite material that is coated and consists of alternating layers of plastic and elastomer material (5).