Air Spring Control Valve with Segmented Tappets for Precise Height Regulation
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Solution Overview
Problem
The response behavior of existing control valves for motor vehicle seats with scissor-type swing systems is not optimal in terms of sensitivity, speed, and fine graduations for height regulation, leading to subpar performance in commercial vehicle seats.
Innovation Solution
A control valve with three tappets that can open or close specific channels for air supply and venting, arranged to prevent simultaneous air supply and venting, featuring rotating control levers, one-piece tappets, and stationary sealing rings to reduce tolerances and wear, and a lubricant reservoir for maintenance-free operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a control valve with two tappets is used, then the structure is simple, but the response behavior in terms of sensitivity and speed is not optimal
Solution Approach 1:
The control valve is divided into three separate tappets (first tappet for venting, second tappet for air supply, third tappet for additional air supply) instead of using a single or two-tappet design. This segmentation allows independent control of different air flow paths, enabling faster and more sensitive response behavior while maintaining manageable structural complexity through modular organization
2Measurement precision
If the full channel cross section is opened immediately, then air supply is fast, but fine graduations of static height setting are lost
Solution Approach 1:
The air supply function is segmented into two separate tappets: the second tappet controls the main air-supply channel while the third tappet controls an additional air supply channel. This allows progressive opening of air flow paths, enabling fine graduations through the second tappet's precise control while the third tappet provides additional flow capacity when fully opened, thus maintaining both precision and speed
Solution Approach 2:
The system uses partial opening of the air supply channels through the second tappet for fine height adjustments, and allows excessive action through the third tappet when rapid height change is needed. This combination enables the system to operate in different modes (fine control vs. rapid adjustment) depending on the operational requirements
3Manufacturing precision
If control means are fixed to constituents other than housing, then installation is easier, but tolerances increase leading to less precise control
Solution Approach 1:
The control means (first, second, and third control means) are merged with the housing by arranging them directly on the housing structure. This integration eliminates the need for separate mounting fixtures or intermediate components, reducing the number of assembly steps while simultaneously minimizing tolerance accumulation that would occur with multiple connection interfaces, thus achieving both precise control and ease of manufacture
4Manufacturing precision
If drag levers or cam discs are used, then the structure is compact, but tolerances increase reducing control precision
Solution Approach 1:
Instead of using drag levers or cam discs that convert rotational motion with tolerance accumulation, the invention uses control means that move linearly or pivot directly on the housing. This inverted approach to motion transmission eliminates the intermediate conversion steps that introduce tolerances, achieving higher precision while keeping the control mechanism relatively simple through direct actuation
Data Source
AI summary
The invention relates to a control valve (16) for an air spring, comprising a housing (41), an exhaust duct that has an exhaust tappet (26) for opening of closing the exhaust duct, which exhaust tappet interacts with a first control means (19), a ventilation duct that has a ventilation tappet (27) for opening or closing the ventilation duct, which ventilation tappet interacts with a second control means (20), and a supplemental duct having a supplemental tappet (28) for opening or closing the supplemental duct, which supplemental tappet interacts with a third control means (21), wherein a first air connection A connects to the exhaust duct and a second air connection P connects to the exhaust duct together with the supplemental duct, wherein a first control means (19) and a second control means (20) are arranged to one another in such a manner that said control means cannot be actuated at the same time by an control element (18), and wherein the second control means (20) and the third control means (21) are arranged to one another in such a manner that the supplemental duct can only be opened when the ventilation duct is opened. The invention further relates to a motor vehicle seat comprising a mechanical swing system and an air spring, which motor vehicle seat has such a control valve.