Pressure Limiting Valve Sleeve Plastic Deformation Adjustment
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Solution Overview
Problem
Conventional pressure limiting valves in fuel injection systems face challenges in achieving a large adjustment range for opening pressure with precise accuracy, requiring complex manufacturing processes and additional components like threads and seals, which increase size and weight, and may not ensure leak-tightness at high pressures.
Innovation Solution
A pressure limiting valve design featuring a sleeve with a constant outer circumference and a fixing pin that plastically deforms to adjust the spring preload, eliminating the need for rotational movement and separate seals, allowing for a large adjustment range without additional components, and ensuring fluid-tightness through texturing and secure pressing into a housing with a constant diameter locating bore.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a rotational adjustment mechanism with threads is used to adjust the opening pressure, then the manufacturing precision of the opening pressure can be improved, but the device complexity and overall space increase due to additional threads and seals
Solution Approach 1:
The patent extracts and eliminates the thread mechanism and separate seal components from the conventional design. Instead of using rotational threads for adjustment, the invention uses a linearly displaceable sleeve that can be directly pressed into the housing, removing the need for complex threading and separate sealing elements while maintaining adjustment precision.
Solution Approach 2:
The patent merges the adjustment mechanism and sealing function into a single integrated sleeve component. The sleeve combines the pressure adjustment function (through axial displacement) and the sealing function (through direct pressing into the housing), eliminating the need for separate threads and seals that would otherwise be required.
2Manufacturing precision
If a rotational thread mechanism is used for adjustment, then the opening pressure can be precisely adjusted, but the adjustment range is limited and the overall size increases
Solution Approach 1:
The patent transitions from rotational adjustment (circular dimension) to linear axial displacement (linear dimension). The sleeve moves along the longitudinal axis of the locating bore, providing a continuous linear adjustment range that is not constrained by the limited angular travel of a thread mechanism, thereby expanding the adjustable pressure range.
Solution Approach 2:
The patent implements a dynamically adjustable sleeve position that can be continuously varied along the axial direction. This linear dynamic adjustment allows for a broader range of opening pressures to be achieved compared to the fixed-step rotational adjustment of thread mechanisms.
3Reliability
If conventional sealing methods with separate seals are used, then leak-tightness at high pressures can be ensured, but the device complexity and space requirements increase
Solution Approach 1:
The patent combines the sealing function directly into the sleeve component itself. The sleeve is designed to be pressed into the housing with an interference fit or deformation mechanism that creates the seal, eliminating the need for separate seal elements like O-rings or gaskets while maintaining effective sealing at high pressures.
Solution Approach 2:
The sleeve performs its own sealing function through its design and installation method. The sleeve's outer circumference is designed to create a seal directly against the housing bore when pressed in, making the sealing function self-contained within the sleeve component rather than requiring additional dedicated sealing elements.
4Manufacturing precision
If threads and separate seals are used for adjustment and sealing, then the opening pressure can be adjusted with good accuracy, but the weight and overall size of the valve increase
Solution Approach 1:
The patent removes the thread mechanism and separate seal components that contribute to the overall weight. By using a simpler linear displacement mechanism for the sleeve and integrating the sealing function into the sleeve itself, the total mass of the pressure limiting valve is reduced while maintaining adjustment accuracy.
Solution Approach 2:
The patent merges multiple functions (adjustment and sealing) into a single sleeve component, reducing the total number of parts and their associated weights. This functional integration eliminates redundant materials and fasteners, resulting in a lighter overall valve assembly.
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 provides a cost-effective, compact, and reliable pressure limiting valve with a large adjustment range, reduced component count, and improved leak-tightness, enabling efficient operation at high pressures without the need for screws or additional seals, thus enhancing the fuel injection system's performance and reducing overall size and weight.
Implementation Method 1
The fixing pin is moved along the longitudinal axis relative to the sleeve and thereby plastically deforms the sleeve, in order to press the sleeve into the housing
Implementation Method 2
A spring force acting on the closing element of the pressure limiting valve is varied
Data Source
AI summary
A pressure limiting valve for a fuel injection system may include a sleeve, a fixing pin, a spring, a sealing element, and a seat. The sleeve may have a longitudinal axis. The fixing pin protruding through a cavity enclosed by the sleeve. The spring may have a first end supported on the sleeve and a second end supported by the sealing element. The seat may provide a sealing surface for the sealing element to block a fluid flow through the valve when closed position, and allow this flow to pass in other positions. The outer circumference of the sleeve may vary within predefined tolerances along the longitudinal axis. The fixing pin may be shaped to plastically deform by a movement of the fixing pin along the longitudinal axis, in order to press the sleeve into the housing.