Servo Valve Chimney Seal Layout for Hydraulic Leak Prevention
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Solution Overview
Problem
Servovalves face challenges with complex and expensive components, vulnerable seals prone to leakage, and difficult assembly and calibration, necessitating an improved sealing mechanism to prevent hydraulic fluid leakage between the torque motor and hydraulic sections.
Innovation Solution
A servovalve design featuring a torque motor section with opposing pole pieces and permanent magnets, an armature/flapper assembly, and a hydraulic section with a chimney-shaped housing, where the sealing means is positioned on the outer surface of the chimney section and contacts both the torsion bridge and the chimney section, providing a more effective seal, potentially using an O-ring seated in a groove.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional sealing means are used in servovalves, then the structure is simpler, but sealing reliability deteriorates due to vulnerable seals prone to leakage
Solution Approach 1:
The sealing system is segmented into multiple functional components: the sealing means (O-ring) positioned on the chimney section, the torsion bridge providing structural support and positioning, and the groove feature that locates the sealing means. This segmentation allows each component to be optimized independently for its specific function while collectively achieving reliable sealing.
Solution Approach 2:
The sealing means acts as an intermediary element between the chimney section and the torsion bridge, creating a fluid-tight barrier. The groove serves as an intermediary feature that positions and retains the sealing means, ensuring proper contact between the seal and both the chimney section outer surface and the torsion bridge inner surface.
2Reliability
If complex sealing mechanisms are used to improve sealing, then sealing reliability improves, but manufacturing difficulty and cost increase
Solution Approach 1:
The groove is provided locally on the outer surface of the chimney section at a specific location to receive and position the sealing means. This localized feature simplifies manufacturing by concentrating the sealing arrangement at a specific point rather than requiring complex sealing mechanisms throughout the entire structure.
Solution Approach 2:
The sealing arrangement allows for larger tolerances in the chimney section and torsion bridge dimensions compared to traditional sealing methods. The O-ring sealing means compensates for dimensional variations, enabling less precise manufacturing while maintaining effective sealing, thereby reducing manufacturing cost and complexity.
3Reliability
If traditional sealing positions are used, then assembly is simpler, but sealing effectiveness deteriorates due to hydraulic fluid leakage
Solution Approach 1:
The groove is pre-formed on the chimney section outer surface to receive the sealing means during assembly. This preliminary preparation of the sealing location simplifies the assembly process, as the sealing means can be directly installed into the pre-positioned groove rather than requiring complex alignment procedures.
Solution Approach 2:
The sealing means, positioned in the groove on the chimney section, automatically contacts both the outer surface of the chimney section and the inner surface of the torsion bridge when the torsion bridge is installed. This self-positioning capability ensures effective sealing without requiring complex assembly procedures or specialized tools.
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 enhances sealing efficiency, simplifies manufacturing and assembly, reduces costs due to larger tolerances, and provides a better seal than traditional methods, making the servovalve more reliable and cost-effective.
Implementation Method 1
first and second permanent magnets may be positioned between these first and second pole pieces
Implementation Method 2
torque motor section may comprise first and second opposing pole pieces and first and second permanent magnets may be positioned between these first and second pole pieces
Implementation Method 3
an armature/flapper assembly which comprises a torsion bridge, an armature plate and a flapper that is connected at a first end to the armature plate
Implementation Method 4
The sealing means is positioned on the outer surface of the chimney section at its first end. The torsion bridge is also provided around the sealing means so that the sealing means contacts both an inner surface of the torsion bridge and the outer surface of the chimney section
Data Source
Figure 1
Figure 2a~2b
Figure 3
AI summary
A servovalve (200) with improved sealing is described herein. The servovalve comprises a torque motor section (10) and a hydraulic section (30). The torque motor section (10) may comprise first and second opposing pole pieces (12a, 12b) and first and second permanent magnets (14a, 14b) may be positioned between these first and second pole pieces (12a, 12b). The torque motor section (10) also comprises an armature/flapper assembly which comprises a torsion bridge (35), an armature plate (15b) and a flapper (21) that is connected at a first end to the armature plate (15b). The flapper (21) extends from said armature plate (15b) along a first longitudinal axis X. The armature plate (15b) may extend between the first and second permanent magnets (14a, 14b) and along a second longitudinal axis Y that is perpendicular to the first axis X. The hydraulic section (30) comprises: a housing (23) that comprises a body section (24) and a chimney section (32). The chimney section (32) extends from the body section (24) to a first end (32a). The chimney section (32) has an outer surface (29) and an internal hollow channel (116) extending along the first longitudinal axis X and from the first end (32a) and into said body section (24). In use, the flapper (21) is positioned so as to extend within this internal hollow channel (116). The servovalve (200) further comprises means for sealing said torque motor section (10) from said hydraulic section (30) so that hydraulic fluid does not leak from the hydraulic section (30) into the torque motor section (10). The sealing means (25) is positioned on the outer surface (29) of the chimney section (32) at its first end (32a). The torsion bridge (35) is also provided around the sealing means (25), so that the sealing means (25) contacts both an inner surface of the torsion bridge (35) and the outer surface (29) of the chimney section (32). This thereby provides an improved seal between the inner surface of the torsion bridge (35) and the outer surface of the chimney section (32). A method of manufacturing such an improved servovalve (200) is also described herein.