Fuel Regulator Limit Cap Structure for Compact Gap Control
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Solution Overview
Problem
Conventional fuel regulators face issues of increased size, component count, and assembly time due to the need for a guide member that enlarges the regulation hole diameter and requires additional components.
Innovation Solution
A fuel regulator design with a restriction groove in the inner peripheral surface of the regulation hole, allowing the limit cap to be engaged with the needle valve without enlarging the outer end diameter, and using a single-piece needle valve with integrated resin components to reduce assembly time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a guide member is fitted into the outer end portion of the regulation hole to reduce the gap size, then the gap between the regulation hole and limit cap is reduced, but the inner diameter of the regulation hole is increased and the number of components is increased
Solution Approach 1:
The guide member function is merged into the limit cap itself. The limit cap is designed with an annular guide portion that extends axially from its outer end, eliminating the need for a separate guide member. This integration reduces the number of components while maintaining the gap control function.
Solution Approach 2:
The limit cap is given multiple functions: it limits the rotation of the needle valve, maintains the gap between the regulation hole and the limit cap, and guides the assembly process through its guide portion. This multi-functionality eliminates the need for separate guide members and other components.
2Ease of manufacture
If a guide member is fitted into the outer end portion of the regulation hole to reduce the gap size, then the gap between the regulation hole and limit cap is reduced, but the size of the main body portion is increased
Solution Approach 1:
The guide function is merged into the limit cap structure rather than being a separate component fitted into the regulation hole. The annular guide portion of the limit cap controls the gap without requiring enlargement of the regulation hole, thus maintaining a compact main body portion.
3Ease of manufacture
If the casting mold is removed in the axial direction of the regulation hole, then the restriction groove is formed, but a groove portion with the same width is formed from the restriction groove through the outer end edge, increasing the diameter
Solution Approach 1:
The casting mold removal direction is changed from axial to radial (perpendicular to the axial direction). This asymmetric removal approach allows the restriction groove to be formed in the inner peripheral surface without creating a groove portion that extends to the outer end edge, thus avoiding diameter increase.
Solution Approach 2:
The mold removal direction is changed from one dimension (axial) to another dimension (radial). This dimensional change allows the restriction groove to be formed without enlarging the outer end portion diameter, as the groove is created by removing material perpendicular to the original axial direction.
4Ease of manufacture
If multiple components are used including a separate guide member, then the gap control is improved, but the assembly time is increased
Solution Approach 1:
The guide member function is merged into the limit cap, reducing the number of components that need to be assembled. The limit cap with its integrated guide portion can be directly assembled into the regulation hole without requiring separate guide member installation, thus reducing assembly time.
Solution Approach 2:
The limit cap performs multiple functions including rotation limitation, gap maintenance, and assembly guidance. This multi-functionality eliminates the need for separate guide members and reduces the number of assembly steps, thereby reducing assembly time.
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 design achieves a compact main body, reduces component count, and shortens assembly time while maintaining precise control over air-fuel ratios without needing special tools.
Implementation Method 1
a first shaft portion which is screwed into the first hole portion
Implementation Method 2
A projecting portion which is inserted into the restriction groove is formed on an outer peripheral surface of the limit cap, and the projecting portion is capable of passing through the guide groove
Implementation Method 3
a second shaft portion which is housed inside the second hole portion are formed. The second shaft portion and the limit cap fitted onto the second shaft portion are configured to be engaged with each other in a circumferential direction of the limit cap
Data Source
AI summary
A fuel regulator includes a limit cap which is attached to a needle valve which is inserted into a regulation hole. In an inner peripheral surface of a second hole portion of the regulation hole, a restriction groove and a guide groove which extends from the restriction groove through an outer surface of a main body portion in an axial direction of the second hole portion are formed. A projecting portion which is inserted into the restriction groove is formed on an outer peripheral surface of the limit cap, and the projecting portion is capable of passing through the guide groove, and in the main body portion, a cast hole which extends from the restriction groove through the outer surface of the main body portion in a direction intersecting the axial direction of the second hole portion is formed.