Resin Sliding Bearing D-Cut Insertion Force Reduction
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Solution Overview
Problem
Existing resin sliding bearings require high force for insertion into through-holes due to their design, making them difficult to manufacture and impractical for stable rotation in image forming apparatuses.
Innovation Solution
A resin sliding bearing with a tubular portion featuring D-cut surfaces, flange portions, an engagement portion, and a protruding portion that allows for easy and stable insertion by elastic deformation, reducing the required insertion force and preventing accidental removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a press-fit sliding bearing with a tubular portion is used to be tightly fitted into a through-hole, then the sliding bearing can be fixed to the support plate, but a large force is required to press the tubular portion into the through-hole
Solution Approach 1:
The outer peripheral surface of the tubular portion is segmented into multiple regions (first region with D-cut surfaces, second region with engagement portion, third region with protruding portion). This segmentation allows different parts of the tubular portion to perform different functions during insertion, reducing the overall insertion force while maintaining fixing reliability.
Solution Approach 2:
Different regions of the outer peripheral surface are given different local qualities: the first region has D-cut surfaces for easy insertion, the second region has an engagement portion for anti-removal, and the third region has a protruding portion for additional engagement. This local differentiation solves the contradiction by optimizing each region's function.
2Force
If an elastic engagement piece is formed in the tubular portion to reduce insertion force, then the sliding bearing can be inserted with small force, but it is difficult to manufacture and not practical
Solution Approach 1:
Instead of forming a complex elastic engagement piece, the patent segments the outer peripheral surface into three regions with simpler features (D-cut surfaces, engagement portion, protruding portion). This segmentation achieves the force reduction effect while maintaining manufacturing simplicity and practicality.
Solution Approach 2:
The patent changes the geometric parameters of the tubular portion's outer peripheral surface by introducing D-cut surfaces and protruding portions. These parameter changes enable elastic deformation during insertion, reducing insertion force without requiring complex elastic engagement pieces.
3Reliability
If the tubular portion is tightly fitted into the through-hole to prevent accidental removal, then the sliding bearing is securely fixed, but the insertion requires large force
Solution Approach 1:
The outer peripheral surface is segmented into regions with different functions: the first region provides insertion ease, while the second and third regions provide anti-removal capability. This segmentation achieves both secure fixation and easy insertion with reduced force.
Solution Approach 2:
The engagement portion and protruding portion create an asymmetric structure on the outer peripheral surface. This asymmetry allows the bearing to be easily inserted in one direction while preventing removal in the opposite direction, solving the contradiction between easy insertion and secure fixation.
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 sliding bearing can be easily and stably inserted into through-holes with minimal force, ensuring secure rotation and reusability while maintaining the shape of the bearing's surface, suitable for various support plate thicknesses.
Implementation Method 1
a protruding portion formed on an outer peripheral surface of the tubular portion at a circumferential position that is outside a region in which the D-cut surface is formed and that is outside a region in which the engagement portion is formed
Data Source
AI summary
A sliding bearing is made of a resin and includes a tubular portion that includes an outer peripheral surface including a D-cut surface. A flange portion, which protrudes from the D-cut surface, is formed at one end portion of the tubular portion. An engagement portion is formed at the other end portion of the tubular portion. A protruding portion is formed on the outer peripheral surface of the tubular portion at a circumferential position that is outside a region in which the D-cut surface is formed and that is outside a region in which the engagement portion is formed.