Valve Unit Pretensioning for Tolerance-Compensated Assembly
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Solution Overview
Problem
Conventional valve units face challenges in maintaining precise control due to manufacturing tolerances and dimensional changes at high temperatures, especially when using plastic components, and threaded connections are costly and time-consuming.
Innovation Solution
A self-locking valve spindle with an elastic element pretensioning mechanism compensates for manufacturing tolerances and temperature-induced expansions, using detent hooks or other fastening methods for a secure and cost-effective assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If threaded connections are used to fasten the valve drive to the housing, then the positioning precision and control accuracy are improved, but the manufacturing cost and assembly time increase
Solution Approach 1:
The patent extracts the fastening function from the main housing structure and implements it through separate detent hooks that engage with recesses. This allows the housing to be manufactured as a simple injection-molded part without integrated threading, reducing manufacturing complexity and cost while maintaining secure positioning of the valve drive.
Solution Approach 2:
The connection system is segmented into discrete detent hooks and corresponding recesses, distributed around the circumference. This segmentation provides multiple engagement points that collectively achieve precise positioning and secure fastening without requiring complex threaded structures, balancing precision with ease of manufacture.
2Measurement precision
If threaded connections are used to fasten the valve drive to the housing, then the positioning precision and control accuracy are improved, but the assembly time increases
Solution Approach 1:
The fastening function is extracted and implemented through simple detent hooks that engage with recesses, eliminating the need for threading operations during assembly. This reduces assembly time significantly while maintaining positioning precision through the distributed engagement points.
Solution Approach 2:
The detent hooks are pre-formed as integral parts of the housing or cover during injection molding, and the recesses are pre-formed in the mating component. This preliminary formation of connection features eliminates time-consuming assembly steps while ensuring precise positioning through the designed geometry of the engagement elements.
3Ease of manufacture
If form-fitting connections or substance-to-substance bonds are used between the housing and cover, then the manufacturing cost is reduced, but the tolerances between the interior of the housing and the valve drive cannot be compensated
Solution Approach 1:
The elastic element is pre-installed between the valve drive and the cover, creating a pretensioning force that compensates for manufacturing tolerances before the detent hooks engage. This preliminary action ensures that the valve drive is positioned accurately relative to the housing interior, compensating for injection molding tolerances while maintaining the simplicity and low cost of form-fitting connections.
Solution Approach 2:
The elastic element changes its physical state from uncompressed to compressed, generating a pretensioning force that actively compensates for manufacturing tolerances. This dynamic parameter change allows the system to adapt to tolerance variations in the injection-molded housing and cover, maintaining precise positioning without requiring more complex or expensive connection methods.
4Device complexity
If the valve drive is not pretensioned by an elastic element, then the assembly is simpler, but the accuracy of the valve unit decreases due to movement during load changes
Solution Approach 1:
The elastic element is pre-installed and pre-compressed between the valve drive and the cover, creating a pretensioning force that prevents movement during operation. This preliminary action secures the valve drive in its correct position relative to the housing interior, maintaining high accuracy while adding minimal complexity to the assembly. The pretensioned state ensures that the valve drive remains stationary during load changes between compression and tension.
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 ensures accurate positioning and simplified assembly, allowing for quick disassembly for maintenance, while maintaining precision under varying loads and temperatures.
Implementation Method 1
the valve drive is pretensioned against the cover by an elastic element, no movement of the valve drive takes place in the housing during the change between a closing and opening of the valve unit, because the manufacturing tolerances between the interior of the housing and the valve drive are compensated
Implementation Method 2
The valve spindle is designed to be self-locking so that the open and closed states are maintained
Data Source
AI summary
A valve unit is provided which has a housing with a cover. Accommodated in the housing is a valve drive which is connected to a valve spindle. A closing body is arranged at an end of the valve drive opposite to the valve spindle. Furthermore, an elastic element is arranged between a contact face in the housing facing away from the closing body and the valve drive, so that the elastic element pretensions the valve drive toward the cover in a closed state of the valve unit. Such a configuration of the valve unit allows the accommodation of a valve unit in a housing to be simplified. Furthermore, the tolerances, for example the manufacturing tolerances of the housing, are compensated for by the pretensioning of the valve drive by the elastic element.