Valve Stem Connection Structure for Pressure Reducing Valves
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Solution Overview
Problem
The existing pressure reducing valve connection structure requires strict dimensional control and is costly due to complex shapes, limiting flexibility in diaphragm inclination and axis displacement.
Innovation Solution
A valve stem connection structure with a reduced diameter stem portion and enlarged diameter stem portions, along with a U-shaped holding plate and expandable engaging ring, allows for simple and cost-effective assembly while enabling diaphragm inclination and axis displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a T-shaped engaging groove with complex asymmetrical shape is used to engage with the valve stem, then the connection structure becomes secure, but the manufacturing cost increases and the groove cannot be formed by low-cost lathing process
Solution Approach 1:
The patent applies asymmetry by providing the engaging groove only on one side of the insertion member rather than symmetric engagement. This asymmetric single-sided engaging groove simplifies the manufacturing process while maintaining reliable connection through the engaging ring that prevents both axial and radial displacement.
2Manufacturing precision
If strict dimensional control is implemented to prevent diaphragm inclination and axis displacement, then the connection precision is improved, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent applies dynamics by allowing the diaphragm rod to have controlled inclination and axis displacement capabilities through the engaging ring mechanism. Rather than rigidly constraining the connection, the design dynamically accommodates dimensional variations while maintaining functional reliability through the engaging groove and ring interaction.
3Reliability
If multiple components (O-ring, retainers, washer, nut) are stacked and fastened to connect the valve stem to the diaphragm, then the connection is secure, but the assembly process becomes complex and time-consuming
Solution Approach 1:
The patent merges multiple fastening functions into a single engaging ring component that provides both axial and radial constraint. This consolidation eliminates the need for separate O-rings, retainers, washers, and nuts, significantly reducing assembly steps and time while maintaining reliable connection through the integrated engaging groove-ring mechanism.
4Ease of manufacture
If a simple engaging groove shape is used that can be formed by lathing process, then the manufacturing cost is reduced, but the connection structure becomes less secure
Solution Approach 1:
The patent introduces an engaging ring as an intermediary component that mediates between the simple lathable engaging groove and the requirement for secure connection. The engaging ring transforms the simple groove geometry into an effective constraint mechanism that prevents both axial and radial displacement, achieving reliable connection with low-cost manufacturing.
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
Facilitates assembly with reduced manufacturing costs and allows for diaphragm inclination and axis displacement, improving the connection's flexibility and ease of processing.
Implementation Method 1
causing an engaging ring expandable and contractable in a radial direction of the valve stem to engage with an arc-shaped first engaging groove provided in an outer periphery of the holding plate and an annular second engaging groove provided in an inner periphery of the insertion recess portion
Data Source
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AI summary
A valve shaft connection structure for a pressure reducing valve is such that an insertion recess (72) which opens toward a valve mechanism is provided coaxially with a diaphragm rod (68); that at one end of a valve shaft (30), there are provided a reduced diameter shaft section (30a) and a pair of expanded diameter sections (30b, 30c), the diameters of the pair of expanded diameter sections (30b, 30c) being larger than that of the reduced diameter shaft section (30a), and each of the pair of expanded diameter sections (30b, 30c) being located at one of the two shaft longitudinal ends of the reduced diameter shaft section (30a); that a holding plate (74) which has an engagement recess (73) that opens toward one side and which is formed in such a way as to have an approximately U-shaped cross section, is inserted into the insertion recess (72), with the reduced diameter shaft section (30a) loosely inserted into the engagement recess (73); and that there is engaged an engagement ring (78) with a first engagement groove (76) which is arc-shaped and is provided around the outer circumference of the holding plate (74) and with a second engagement groove (77) which is annular and is provided around the inner circumference of the insertion recess (72), the aforementioned engagement ring (78) being permitted to expand and shrink along the radial direction of the valve shaft (30). Due to the above, it is possible to connect the valve shaft (30) to the diaphragm rod (68) under a simple configuration with low production cost, while permitting inclination of a diaphragm with respect to a plane perpendicular to the valve shaft direction, as well as mispositioning of the diaphragm center and the valve body shaft center.