Oil Pan Drain Plug With Cantilevered Arms For Loosening Prevention
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Solution Overview
Problem
The existing drain plug structures for oil pans rely heavily on the elastic strength of turning-restricting projections for loosening prevention, which can lead to excessive shear friction and wear, resulting in a loss of the loosening-prevention function over time, especially with repeated attachment and detachment.
Innovation Solution
A drain plug structure featuring a columnar stopper with cantilevered arcuate arm portions and a loosening-prevention meshing portion that engages in a recess/projection configuration, allowing for elastic deformation and reducing shear friction, thereby maintaining the loosening-prevention function even after repeated use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a turning-restricting projection is used to prevent loosening of the drain plug, then the loosening-prevention function is demonstrated, but the projection is worn and crushed due to excessive shear friction force when removed
Solution Approach 1:
The turning-restricting projection is divided into a first projection on the drain plug and a corresponding first recess on the oil pan. This segmentation distributes the shear friction force across two separate engagement points, preventing excessive stress concentration on a single projection and thereby improving its durability while maintaining the loosening-prevention function.
Solution Approach 2:
A second projection and second recess are introduced as intermediary elements that work in conjunction with the primary turning-restricting projection. This additional engagement mechanism shares the load and reduces the shear friction force on the original projection, preventing wear and crushing while maintaining reliable loosening prevention.
2Device complexity
If a single turning-restricting projection is used for loosening prevention, then the structure is simple, but excessive shear friction force causes wear and loss of function over time
Solution Approach 1:
The turning-restricting projection is segmented into multiple projections (first projection and second projection) with corresponding recesses. This segmentation improves reliability by distributing shear friction forces across multiple engagement points, preventing wear and loss of function over time while maintaining reasonable structural simplicity.
Solution Approach 2:
Multiple turning-restricting projections and recesses are combined to work together as an integrated loosening-prevention system. This merging of multiple engagement mechanisms enhances reliability by providing redundant load paths, ensuring the function persists even under repeated attachment and detachment cycles.
3Device complexity
If the turning-restricting projection relies on its own elastic strength to overcome the engaging recess, then the structure is simple, but the shear friction force becomes excessively large
Solution Approach 1:
The turning-restricting projection mechanism is segmented into multiple projections and recesses that engage sequentially. This segmentation distributes the shear friction force across multiple contact points, significantly reducing the force required at each individual engagement point while maintaining the overall loosening-prevention function.
Solution Approach 2:
Additional projections and recesses act as intermediary elements that facilitate the loosening process by providing progressive engagement points. These intermediaries reduce the peak shear friction force by distributing the mechanical work across multiple smaller steps, making removal easier while maintaining structural simplicity.
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 solution effectively suppresses wear on the loosening-prevention meshing portions and ensures a stable loosening-prevention function, enhancing the durability of both the drain plug and oil pan by minimizing excessive shear friction during rotation and detachment.
Implementation Method 1
the arcuate arm portions which are formed projecting radially outwards from the outside exposed end portion of the columnar stopper portion and are also arranged in series along a circumferential direction... when the recess/projection engagement of both of the loosening-prevention meshing portions is released, elastic deformation can take place from a root portion of the cantilevered arcuate arm portions
Data Source
AI summary
The present disclosure describes a drain plug structure for an oil pan for an internal combustion engine. The drain plug structure closes off a drain hole disposed in a bottom portion of the oil pan. The drain plug structure includes a columnar stopper portion inserted into the drain hole and rotated to prevent withdrawal. A sealing member is fitted to an outer periphery of the columnar stopper portion. An operating portion for a rotation operation is disposed on an outside exposed end portion of the columnar stopper portion. A plurality of cantilevered arcuate arm portions project radially outwards from the outside exposed end portion of the columnar stopper portion and are arranged in series along a circumferential direction. A loosening-prevention meshing portion is disposed on a tip end portion of each arcuate arm portion and an opening edge portion of the drain hole.