Valve Assembly Hydraulic Coupling for Injection Precision
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Solution Overview
Problem
Conventional fluid injection valves suffer from long tolerance chains among components, leading to part-to-part and shot-to-shot variability in fluid quantity, affecting hydraulic damping and resulting in unpredictable fluid injection behavior.
Innovation Solution
The valve assembly features a driving device with radially extending coupling surfaces that overlap at least 35% of the cavity's cross-sectional area, allowing hydraulic interaction to displace the valve needle, and includes a disc element and stoppers for precise momentum transfer, reducing axial overlap and guiding complexity, and utilizing an electromagnetic actuator assembly with a guide sleeve for independent axial guidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional injection valves use multiple components (armature, pole piece, valve needle) with overlapping surfaces for hydraulic interaction, then the valve can achieve fluid injection function, but long tolerance chains among components generate large part-to-part and shot-to-shot variability of fluid quantity injected
Solution Approach 1:
The valve assembly is segmented into functionally independent modules: the valve needle module (with sealing element) and the driving device module (electromagnetic actuator), which are axially displaced relative to each other. This segmentation breaks the long tolerance chain by eliminating the need for precise alignment between armature, pole piece, and valve needle, as each module can be manufactured and assembled independently with tighter individual tolerances.
Solution Approach 2:
A sustaining spring is introduced as an intermediary element between the driving device and the valve needle. This spring absorbs tolerance variations and provides continuous contact force, ensuring reliable force transmission while compensating for dimensional variations in the components. The spring acts as a buffer that decouples the tolerance chains of the electromagnetic actuator and the valve needle.
2Reliability
If conventional injection valves use overlapping radial surfaces of armature and valve needle for hydraulic interaction, then the valve can transfer force, but the complex tolerance chains affect hydraulic damping in an unpredictable way
Solution Approach 1:
The hydraulic interaction function is extracted from the overlapping radial surfaces between armature and valve needle, and relocated to the axial interface between the driving device and the valve needle. This extraction eliminates the complex three-dimensional tolerance chain involving multiple overlapping surfaces, replacing it with a simpler axial interface where hydraulic damping can be more predictably controlled.
Solution Approach 2:
The complex mechanical-hydraulic interaction through overlapping radial surfaces is replaced by a simplified axial mechanical interface with controlled hydraulic damping. The sustaining spring provides consistent mechanical contact force, while a controlled fluid gap provides predictable hydraulic damping, replacing the unpredictable damping from complex tolerance chains.
3Device complexity
If the valve needle is axially guided by the pole piece, then the valve assembly structure is simplified, but the tolerance chain between armature and valve needle increases variability
Solution Approach 1:
The guidance function is segregated from the force transmission function. The valve needle is axially guided by the valve body bore rather than the pole piece, separating the guidance tolerance chain from the electromagnetic actuation tolerance chain. This allows each function to be optimized independently with appropriate tolerances.
Solution Approach 2:
The valve body bore acts as an intermediary guidance structure between the valve needle and the external environment. This intermediate guidance mechanism provides stable axial alignment without requiring tight tolerances between the moving components, reducing the overall tolerance chain sensitivity.
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 achieves precise and reproducible flow rates with reduced nonlinearity in flow rate over valve opening time, minimizing interference and ensuring accurate fluid injection, particularly at high pressures.
Implementation Method 1
an electromagnetic actuator assembly (50) which comprises a stationary pole piece (52) and a moveable armature (54), wherein the driving device (40) comprises the armature (54) or consists of the armature (54)
Implementation Method 2
the driving device (40) is configured and arranged for taking the disc element (32) with it for displacing the valve needle (30) in the opening direction (D) solely by means of hydraulic interaction between the coupling surfaces (321, 401)
Data Source
AI summary
A valve assembly may include: a valve body with a longitudinal axis and a cavity; a valve needle; and a driving device for displacing the valve needle. In some embodiments, the valve needle comprises a disc element. The disc element and the driving device comprise mutually facing and radially extending coupling surfaces, the coupling surfaces having an overlapping area of at least 35% of the cross-sectional area of the cavity. The driving device takes the disc element with it for displacing the valve needle in the opening direction solely by means of hydraulic interaction between the coupling surfaces when the driving device is displaced in the opening direction. The coupling surface of the driving device engages in a form-fit connection with the coupling surface of the disc element for pushing the valve needle towards the closing position.