Electromagnetic Fuel Injection Valve Annular Gap Design
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Solution Overview
Problem
Electromagnetic fuel injection valves experience reduced opening and closing response and increased wear due to unbalanced loads caused by manufacturing errors, leading to high frictional resistance between sliding members and the fixed core.
Innovation Solution
Incorporating an annular gap between the fixed core and guide bush, and between the valve stem and sliding member, which allows for elastic deformation to absorb unbalanced loads, thereby reducing friction and enhancing the valve's opening and closing response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a sliding member is secured to the valve stem and slidably supported on the fixed core to stabilize valve element attitude, then the valve element's opening and closing attitude is stabilized, but unbalanced loads from manufacturing errors cause high frictional resistance and rapid wear
Solution Approach 1:
The sliding member is divided into multiple segments along its length, with at least one expansion section that can independently deform. This segmentation allows the sliding member to absorb unbalanced loads through localized elastic deformation of the expansion section, reducing friction and wear while maintaining overall structural stability and attitude control functionality
Solution Approach 2:
The cross-sectional area of the sliding member is varied along its length, creating an expansion section with larger cross-sectional area than adjacent sections. This parameter change enables the expansion section to serve as an elastic buffer that deforms under unbalanced loads, absorbing manufacturing errors and reducing frictional resistance while maintaining attitude stability
2Strength
If the sliding member is press-fitted onto the valve stem to ensure firm connection, then the connection strength is improved, but the sliding member deforms and increases frictional resistance
Solution Approach 1:
The sliding member is divided into a press-fitted section and an expansion section with distinct functions. The press-fitted section provides firm connection to the valve stem through interference fit, while the expansion section remains undeformed during press-fitting to maintain its elastic buffering capability, reducing friction and wear
Solution Approach 2:
Different sections of the sliding member have different cross-sectional areas optimized for their specific functions. The press-fitted section has smaller cross-sectional area for firm connection, while the expansion section has larger cross-sectional area for elastic deformation, allowing each local region to perform its designated function optimally
3Manufacturing precision
If the guide bush is press-fitted into the fixed core to ensure precise guidance, then the guidance precision is improved, but the guide bush deforms and increases frictional resistance
Solution Approach 1:
The guide bush is divided into a press-fitted section and a sliding section. The press-fitted section is deformed during assembly to ensure firm connection and precise guidance, while the sliding section remains undeformed to maintain smooth sliding surface and reduce frictional resistance
Solution Approach 2:
Different sections of the guide bush have different functional requirements. The press-fitted section is designed for deformation during assembly to achieve precise guidance, while the sliding section is designed to remain undeformed to maintain low friction, allowing each local region to perform its designated function optimally
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 annular gaps enable smooth sliding between the guide bush and sliding member, improving the valve element's response and reducing wear, while preventing deformation from press fitting loads, thus stabilizing the valve's opening and closing attitude.
Implementation Method 1
a portion of the guide bush or the sliding member corresponding to the annular gap is elastically deformed so that the unbalanced load can be absorbed
Implementation Method 2
the movable core is caused to be attracted to the fixed core by energizing the coil so as to open the valve element
Data Source
AI summary
In an electromagnetic fuel injection valve which is configured to absorb an unbalanced load applied to sliding portions between a fixed core and a valve stem, thereby enabling a reduction in a frictional resistance of the sliding portions, a guide bush is press fitted in an inner peripheral surface of the fixed core, the valve element includes a valve part configured to cooperate with the valve seat, and the valve stem continuously provided to the valve part and extending toward the guide bush, a sliding member configured to be slidably fitted to an inner peripheral surface of the guide bush is press fitted on the valve stem, wherein an annular gap is provided at least at one of a location between the fixed core and the guide bush and a location between the valve stem and the sliding member, within sliding regions of the guide bush and the sliding member.