Tire Building Drum Core Positioning and Tensioning
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Solution Overview
Problem
Current methods for producing green tires face challenges in achieving accurate core positioning, maintaining consistent thread length, and requiring a two-step process, which limits repeatability and leads to core loss during crowning.
Innovation Solution
A tire building drum with a core clamp and core fixation system, featuring adjustable drum halves and a central part with variable diameter, allows for precise core placement and tensioning of carcass threads, enabling uniform thread lengths and a single-stage production process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If permanent core clamping is used from the inside, then core positioning is maintained, but layer turnover is limited to upwards only and positioning accuracy is insufficient
Solution Approach 1:
The core clamp is designed to be movable rather than fixed, allowing it to be positioned, activated, and deactivated at different stages of the tire building process. This dynamic capability enables the core to be securely clamped during material placement while allowing flexibility for layer turnover operations in both upward and downward directions.
Solution Approach 2:
The tire building drum is divided into functional segments including the core clamp mechanism and core fixation system. This segmentation allows independent control of core positioning and clamping functions, improving both positioning accuracy and operational flexibility without compromising core stability.
2Adaptability or versatility
If a two-step process is used for tire production, then complex tire shaping is achieved, but production time increases and repeatability decreases
Solution Approach 1:
Multiple tire building operations including core placement, material layering, and sidewall shaping are merged into a single continuous process using one tire building drum. The drum's ability to expand radially and accommodate various tooling allows complex tire configurations to be achieved in one step rather than requiring transfer between drums or multiple processing stages.
Solution Approach 2:
The tire building drum is designed with universal capabilities to perform multiple functions: core placement, material positioning, layer turnover, and sidewall shaping. This multi-functional design eliminates the need for specialized equipment for different process stages, improving both productivity and process repeatability.
3Ease of operation
If thread length between cores is not clearly defined, then material placement is flexible, but manufacturing precision and tire uniformity deteriorate
Solution Approach 1:
Manual or mechanical measurement methods for thread length are replaced with an electronic measuring device that automatically measures the thread length between cores. This substitution provides precise, consistent measurements while maintaining operational flexibility, ensuring manufacturing precision without restricting material placement flexibility.
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
This solution enhances positioning accuracy, ensures consistent thread lengths, and allows for a one-step tire production process, reducing core loss and improving tire uniformity and manufacturing efficiency.
Implementation Method 1
the central part is expanded in a radial direction and the strip-like material on the tire building drum is thereby tensioned. This achieves a linear stretching of the carcass threads
Implementation Method 2
The core setters can then press the cores against the side flanks of the expanded middle section in order to fix them there
Data Source
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AI summary
The invention relates to a method and a device which are used for producing a tire blank. At least two strip-shaped materials are positioned on a tire building drum. At least two cores are set in place. The tire building drum is provided with both a core-clamping element and a core-securing element. The core-securing element is forcibly guided via a lever. The tire building drum consists of a central portion and two drum halves arranged on both sides next to said central portion. The drum halves are arranged such that they can be positioned in an axial direction. The central portion has a variable diameter in a radial direction. A radial enlargement of the diameter of the central portion is carried out prior to the cores being set in place. The central portions can be covered externally with a center sleeve which is made of a stretchable material. Furthermore, it is possible to contour the central portions in such a way that reinforcing strip pockets are formed, which favor the production of tires with reinforced side walls.