Rolling Piston Snap Connection for Air Spring Volume and Weight
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Solution Overview
Problem
Existing rolling pistons for air spring rolling bellows are either heavy and expensive due to sheet steel construction or lightweight but inefficient in using internal volume and requiring complex multi-material production, with assembly and manufacturing challenges.
Innovation Solution
A lightweight, two-piece rolling piston design featuring a latching or snap connection and rib-like stiffening elements, made entirely of plastic with an airtight connection via butt welding, allowing for easy assembly and manufacturing without additional material inserts, and optimized for transverse force absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a rolling piston is made of sheet steel with deep-drawn construction, then the internal volume is fully usable and connection strength is high, but the weight increases and manufacturing cost increases
Solution Approach 1:
The rolling piston is divided into two separate parts: a lower piston part and an upper piston part. These parts are connected in an airtight manner to form the complete piston assembly. This segmentation allows each part to be optimized independently and simplifies manufacturing while maintaining full internal volume utilization.
Solution Approach 2:
The material parameter is changed from sheet steel to plastic for the piston body, significantly reducing weight. The connection method parameter is changed from welding/screwing to a snap connection with latching profile, simplifying assembly. These parameter changes resolve the contradiction between weight and volume utilization.
2Weight of moving object
If a rolling piston is made of one-piece plastic, then weight is reduced and manufacturing is simplified, but the internal volume is not fully used and connection strength is insufficient
Solution Approach 1:
The piston is segmented into lower and upper parts that can be manufactured separately and then connected. This allows the use of lightweight plastic material while maintaining structural integrity through the airtight connection between parts, resolving the strength concern.
Solution Approach 2:
The snap connection mechanism combines plastic material with a specifically designed geometric structure (latching profile with projection and receiving opening). This composite approach of material plus structural feature provides sufficient connection strength for withstanding transverse forces while keeping the overall weight low.
3Strength
If metal fastening parts are embedded in plastic piston, then connection strength is improved, but manufacturing complexity increases and additional materials are required
Solution Approach 1:
The metal fastening parts are extracted from the design and replaced with a purely plastic snap connection mechanism. The latching profile with projection and receiving opening provides the necessary connection function without requiring metal inserts, reducing manufacturing complexity and material variety.
Solution Approach 2:
The entire piston assembly, including the connection mechanism, is made from the same plastic material. This homogeneity eliminates the need for metal inserts and simplifies manufacturing to a single material processing workflow, reducing device complexity while maintaining sufficient strength through optimized geometric design.
4Reliability
If a latching connection is designed for transverse forces, then connection reliability is improved, but the structure becomes more complex
Solution Approach 1:
The latching profile is implemented locally at the connection interface between the lower piston part and the connecting part. The projection on the connecting part engages with the complementary receiving opening in the piston head, creating a targeted reinforcement exactly where transverse forces occur, without adding complexity to the overall structure.
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 results in a lightweight, efficient, and cost-effective rolling piston that fully utilizes internal volume, easily assembled and manufactured, capable of handling large transverse forces while maintaining excellent strength and assembly properties.
Implementation Method 1
The rolling piston consists of at least two parts and has a pot-shaped lower piston part and an upper piston part which is connected to the lower piston part in an airtight manner
Implementation Method 2
the latching or snap connection has a projection arranged in the connecting part and provided with a latching profile) or a latching pin protruding from the connecting part in the direction of the piston head
Implementation Method 3
the interior of the rolling piston being connected to the interior of the air spring and air spring rolling bellows and rolling piston being arranged between a sprung or an unsprung mass
Data Source
Figure 1
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AI summary
The invention relates to a rolling piston (1) for a rolling lobe air spring, the interior (2) of which piston is connected to the interior of the air spring and which is composed of at least two parts, that is a crucible-shaped piston skirt (4) and a piston crown (5) that is connected to the piston skirt in an air-tight manner, wherein a detent or snap connection (11, 12, 19, 20, 22, 24) interacting with the connecting part of the mass connected to the piston skirt is provided on the piston head (6) or the in the lower region of the rotationally symmetrical piston wall (7) of the piston skirt.