Fuel Pump Flange Stop Structure for Tank Contraction Stress
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Solution Overview
Problem
Conventional fuel supply devices face issues with excessive contraction of the fuel tank, leading to localized stress concentration on the cover member, which can cause deformation, and there is a need to prevent both the deformation of the cover member and excessive contraction of the fuel tank in the height direction.
Innovation Solution
A fuel supply device with a height interval restricting mechanism, featuring an upper abutment portion and a lower abutment portion that restrict the minimum height interval between the cover member and the joint portion, dispersing stress through a tapered configuration and utilizing a diagonally cut cylindrical shape to prevent deformation, and incorporating a hollow section to reduce weight and a fitting tubular portion for part of the upper abutment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the fuel tank contracts excessively in the height direction, then the internal pressure variation is accommodated, but the cover member deforms due to localized stress concentration
Solution Approach 1:
A buffer member is introduced as an intermediary component between the cover member and the fuel tank. This buffer member absorbs the contraction force when the fuel tank decreases in height, preventing direct stress transmission to the cover member. The buffer member acts as a mediator that protects the cover member from deformation while allowing the fuel tank to accommodate pressure variations.
Solution Approach 2:
The buffer member changes its physical state or dimensions in response to fuel tank contraction. When the fuel tank contracts, the buffer member compresses or deforms to absorb the force, changing its volume or shape parameters. This parameter change allows the buffer member to accommodate the height variation while protecting the cover member from stress concentration.
2Length of stationary object
If connecting shafts are used to limit fuel tank contraction, then the minimum height interval is maintained, but the cover member deforms due to stress concentration on the shafts
Solution Approach 1:
The buffer member serves as an intermediary that maintains the minimum height interval without requiring connecting shafts. By positioning the buffer member to contact the cover member when the fuel tank contracts, it ensures the height interval is maintained while distributing stress away from the cover member, eliminating the need for metal connecting shafts that cause stress concentration.
3Weight of moving object
If the cover member is made of resin for lightweight construction, then the overall weight is reduced, but the cover member deforms under localized stress
Solution Approach 1:
The buffer member acts as a protective intermediary between external forces and the resin cover member. When contraction forces occur, the buffer member absorbs and distributes these forces, preventing localized stress concentration on the lightweight resin cover member. This allows the cover member to maintain its lightweight resin construction while gaining protection against deformation.
Solution Approach 2:
The buffer member functions as a flexible protective element that can deform elastically to absorb stress. This flexible component protects the thinner, lighter resin cover member from rigid stress concentrations, allowing the cover member to be made of lightweight materials while maintaining structural integrity through the protective buffer.
Data Source
AI summary
A fuel supply device includes a flange unit and a pump unit. The flange unit includes a flange main body for closing an opening formed in an upper wall of a fuel tank. The pump unit includes a joint member that is connected to the flange main body so that both components may be movable relative to each other in the vertical direction. The interval in the vertical direction between the flange main body and the joint member is restricted from going below a minimum vertical interval. The minimum interval occurs when a stand-off portion provided as part of the flange main body and a connecting plate portion provided as part of the joint member come into mutual contact with each other and abut each other in the vertical direction.