Pilot Solenoid Valve Spring Preload for Stable Flow Control
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Solution Overview
Problem
Existing miniature solenoid valves face challenges in producing reproducible flow values and ensuring low absorbed power, due to the variability of operating points of springs and magnetic forces, which complicates the control of the race and recall force of the flat mobile nucleus.
Innovation Solution
The solenoid valve design incorporates a flat spring associated with a holding ring to adjust the pre-load force independently of the flat mobile nucleus's race, allowing for better control of the race and recall force. This design also includes a monobloc structure and specific geometric features to optimize the magnetic flow and reduce mass, ensuring maximum airflow with minimal pressure difference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a flat moving core is used to reduce mass, then the absorbed power is reduced, but the control of stroke and return force becomes difficult due to variability of spring operating points and magnetic forces
Solution Approach 1:
The spring system is segmented into two independent functions: a first flat spring dedicated to sealing the supply orifice and a second flat spring (or conical spring) dedicated to guiding and centering the flat moving core. This segmentation allows independent optimization of sealing force and mechanical guidance, eliminating the coupling between spring operating point variability and stroke control.
Solution Approach 2:
The invention changes the geometric parameters of the flat moving core, particularly making it conical rather than cylindrical. This parameter change optimizes the magnetic flux distribution and magnetic forces, improving the controllability of stroke and return force while maintaining low mass.
2Weight of moving object
If the outer diameter of the flat moving core is reduced to limit mass, then absorbed power is reduced, but friction increases due to very low thickness requiring guide washers
Solution Approach 1:
The invention extracts and eliminates the guide washer component by transitioning to a conical flat moving core design. The conical geometry inherently provides self-centering and guidance functions without requiring additional friction-generating components, thus taking out the harmful friction element while maintaining the low mass benefit.
Solution Approach 2:
Instead of adding guide washers to reduce friction (which increases device complexity), the invention inverts the approach by designing the flat moving core itself with a conical shape that inherently provides low-friction guidance and centering, eliminating the need for separate guiding components.
3Object-generated harmful factors
If two flat springs are used to guide the plunging core and eliminate friction, then manufacturing complexity increases, but this approach cannot be directly applied to flat moving core design
Solution Approach 1:
The first flat spring serves multiple functions simultaneously: it provides sealing force for the supply orifice and acts as a return spring for the flat moving core. This multi-functionality reduces the number of components needed compared to using separate springs for each function, thereby reducing device complexity while maintaining low friction.
4Use of energy by moving object
If the geometry of the flat moving core is optimized to reduce mass, then absorbed power is reduced, but the control of magnetic flux and air gap becomes more difficult
Solution Approach 1:
The invention changes the geometric parameters of the flat moving core from cylindrical to conical, with specific optimization of the cone angle and dimensions. This parameter change creates a self-centering effect that automatically maintains the optimal air gap, eliminating the need for complex external guidance mechanisms and achieving both low mass and precise air gap control.
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 achieves reproducible flow values and low absorbed power by effectively controlling the race and recall force of the flat mobile nucleus, optimizing the dynamic force, and reducing the mass and volume of the solenoid valve, thereby enhancing its efficiency and performance.
Implementation Method 1
The construction principle of miniature solenoid valves is based on electromagnets
Implementation Method 2
the variability of the spring operating points depending on the characteristics of the electromagnet's magnetic forces
Implementation Method 3
This force, adjustable during assembly, is called pre-load
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The invention relates to a solenoid valve including an electromagnet (17, 4, 3, 10) made of a flat movable core (10), a fixed core (3) and a coil (17), the solenoid valve comprising a body (4) which also belongs to the electromagnet and includes an opening (23) located at the rear of the body (4), opposite the supply opening (18), for inserting the flat movable core (10), the fixed core (3) and the coil (17). The body (4) is secured to a retaining ring (8) made of a non-magnetic material, a flat spring (9) being compressed between the retaining ring (8) and the flat movable core (10).