Ventilation Unit Valve Stem Segmentation for Spring Positioning
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Solution Overview
Problem
Existing ventilation units for vulcanization molds face challenges in achieving an exact and optimal fit of helical compression springs, leading to improper functioning and requiring excessive time for assembly, with inadequate positioning causing valve disks to fail in closing properly during tire molding.
Innovation Solution
The design includes a cylindrical holding section on the valve stem with a larger diameter and a height of at least 1.0 mm, allowing the helical compression spring to be securely attached with closely spaced coils that can be automatically positioned, ensuring precise and centered application, and enabling the use of springs with different strengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the valve stem has a constant diameter on which the helical compression spring is pushed, then the assembly is simpler, but the helical compression spring cannot be precisely positioned and requires excessive assembly time
Solution Approach 1:
The valve stem is segmented into different sections: a base section with constant diameter for simple spring placement, and a holding section with larger diameter for precise spring positioning. This segmentation allows the spring to be both easily installed and accurately positioned, resolving the contradiction between manufacturing simplicity and assembly time.
Solution Approach 2:
The holding section is designed in advance with specific dimensions (larger diameter and minimum height of 1.0 mm) to pre-establish the correct positioning features for the helical compression spring. This preliminary design ensures that during assembly, the spring can be quickly and accurately positioned without requiring additional adjustment time.
2Productivity
If the helical compression spring is positioned loosely around the valve stem, then the assembly process is faster, but the valve disk does not close properly or tilts during molding
Solution Approach 1:
The holding section of the valve stem has a locally different quality (larger diameter) compared to the base section. This local variation provides a specific engagement feature for the helical compression spring, ensuring reliable positioning and proper valve disk closure while maintaining overall assembly efficiency.
3Manufacturing precision
If the valve stem has a holding section with larger diameter, then the helical compression spring can be precisely positioned, but the valve stem structure becomes more complex
Solution Approach 1:
The valve stem is divided into two functional segments: a base section with constant diameter for simple manufacturing and spring placement, and a holding section with larger diameter for precise spring positioning. This segmentation achieves high positioning precision while keeping the overall structure relatively simple and manufacturable.
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 design ensures precise and automatic positioning of the valve stem with the helical compression spring, reducing assembly time and preventing deformation, thereby ensuring proper functioning of the ventilation unit and preventing rubber expulsion during tire molding.
Implementation Method 1
a helical compression spring that surrounds the valve stem and is supported at one end against the housing and at the other end against the valve disc
Data Source
Figure 1a~1b
Figure 2~3a
Figure 3b~4
AI summary
The invention relates to a ventilation unit (3) for a vehicle pneumatic tire vulcanization mold comprising a cylindrical housing (6), which can be pressed into a ventilation bore (2) in the vulcanization mold, and a valve insert (7) which is positioned in the housing (6) and movable with respect thereto and which has a valve stem (8) having a valve disc (4, 4', 4") and a helical compression spring (9) surrounding the valve stem (8), one end of the compression spring being supported on the housing (6) and the other end being supported on the valve disc (4, 4', 4"). The valve stem (8) has a base portion (8a) having an external diameter (d6), which is greater than the internal diameter of the helical compression spring (9). A cylindrical holding portion (16a), onto which the helical compression spring (9) can be firmly fitted, is connected to the valve disc (4), the holding portion (16a) having a larger diameter than the base portion (8a), wherein the helical compression spring (9) has at least two closely spaced turns at least on the end thereof which can be fitted onto the holding portion (16a).