Fuel Supply Device Pump Unit Guide Structure
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Solution Overview
Problem
Existing fuel supply devices for internal combustion engines face difficulties in smooth insertion into fuel tanks due to potential sticking issues at the opening, requiring substantial time and effort for attachment.
Innovation Solution
The fuel supply device features a pump unit with a recessed portion on its lower base and a guide portion on its upper base, allowing relative movement and preventing sticking by guiding the edge around the opening with an inclined surface, along with a connecting portion that includes a rod member with a joint for smooth vertical movement and a curved lower end to avoid seal member interaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the pump unit is passed through the opening while being laterally moved, then the fuel supply device can be attached to the fuel tank, but the device may get stuck near the opening due to the recessed portion and rod member contacting the edge
Solution Approach 1:
The recessed portion is designed with a curved surface that gradually increases in width from top to bottom, and the rod member has a curved lower end, allowing these surfaces to smoothly guide the edge around the opening during insertion rather than creating sharp contact points that cause sticking
Solution Approach 2:
The connecting portion is designed to be slidable along the rod member, allowing dynamic adjustment during insertion to accommodate slight misalignments and prevent the rod member from getting caught on the edge
2Device complexity
If the recessed portion has parallel planes, then the structure is simple, but the edge around the opening gets stuck on the recessed portion
Solution Approach 1:
The recessed portion features a curved surface with gradually increasing width rather than parallel planes, creating a tapered geometry that guides the edge smoothly through the opening without causing sticking, while maintaining manufacturing simplicity
3Length of moving object
If the leading end of the rod member is long, then the connecting portion has sufficient travel distance, but the leading end gets stuck on the edge around the opening or seal member
Solution Approach 1:
The lower end of the rod member is formed with a curved surface instead of a flat end, allowing it to smoothly pass by the edge around the opening and seal member during insertion, preventing sticking while maintaining sufficient length for connecting portion travel
Data Source
AI summary
A fuel supply device has a cover member which is attached to an opening of a fuel tank, a pump unit comprising a pump, and a connecting portion configured to connect the cover member and the pump unit. A connecting shaft which is formed to one of the two connected members of the connecting portion is inserted into a connecting hole which is formed to the other of the two such that the pump unit is connected to be relatively movable to the connecting portion. The pump unit includes an upper base on which the pump is placed, and a lower base which contacts to the fuel tank. The upper base and the lower base are coupled through attachments whereby an engagement portion of the upper base is fitted into a recessed portion formed on the side of the lower base. The recessed portion has a pair of planes opposing to each other and oriented toward a bottom surface of the lower base from a predetermined position. The recessed portion is further configured such that an interval between a pair of the planes is gradually increased toward the bottom surface.