Cylindrical Fitting Structure with Engaging Portions for Sealing
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Solution Overview
Problem
Existing fitting structures of cylindrical members, such as those in vehicle steering gear boxes, face issues with detachment due to oscillation and require significant time and effort for assembly, particularly due to the lack of centerline movement restriction and the difficulty in fixing rubber-made components.
Innovation Solution
The introduction of engaging portions on the first and second fitting cylinders, along with a sealing member that is pressed by the first fitting cylinder and flange, limits movement in the cylinder's centerline direction, ensuring secure engagement and simplified assembly by utilizing protruding portions, through holes, notches, and raised portions to maintain sealing and prevent detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the first fitting cylinder and second fitting cylinder are fitted to each other by strongly pressing the O ring radially outward and radially inward, then sealing is achieved, but nothing is provided to limit the movement of the cylinders in the center line direction, causing misalignment and detachment during oscillation
Solution Approach 1:
The fitting structure is divided into multiple functional elements: the first fitting cylinder with engaging portions, the second fitting cylinder with corresponding engaged portions, and the O ring sealing element. This segmentation allows each component to perform its specific function - the engaging portions handle axial positioning and anti-detachment, while the O ring handles radial sealing, resolving the contradiction between sealing and alignment stability
Solution Approach 2:
The engaging portions and engaged portions are pre-formed on the fitting cylinders before assembly. These features are designed in advance to automatically limit axial movement when the cylinders are fitted together, preventing misalignment before it can occur during oscillation, while the O ring is simultaneously compressed to provide sealing
2Reliability
If an annular double-sided tape is adhered to the flange and the O ring is fitted in the recess, then sealing and attachment are achieved, but it takes time and effort to adhere the tape and fit the O ring
Solution Approach 1:
The fitting cylinders are designed with self-aligning engaging portions and engaged portions that automatically limit axial movement when assembled. The O ring is designed to be elastically compressed between the flange and the first fitting cylinder, creating self-locking and self-sealing features that eliminate the need for additional adhesive tapes or complex fitting procedures, significantly reducing assembly time and effort
Solution Approach 2:
The design changes the approach from using adhesive bonds (double-sided tape) to mechanical interlocking (engaging portions and engaged portions). This parameter change in the attachment mechanism transforms the assembly process from a time-consuming adhesive application and curing process to a quick mechanical fitting operation, while maintaining reliable attachment
3Reliability
If the column hole cover is made of rubber to provide flexibility, then sealing is improved, but it becomes difficult to fix the location of the column hole cover and insert the cylindrical bush
Solution Approach 1:
The structure is segmented into a rigid housing component and a flexible sealing component (O ring). The rigid first fitting cylinder provides structural support and positioning, while the elastic O ring provides sealing functionality. This segmentation allows the rigid parts to be easily assembled and positioned, while the elastic sealing element accommodates minor misalignments and provides the necessary seal, resolving the contradiction between fixability and sealing
Data Source
AI summary
A recess is formed in an outer circumferential surface of a first fitting cylinder. A flange and a second fitting cylinder are provided at one end of a second cylindrical member which is part of a dust cover. A sealing member is attached to the flange. A protruding portion is provided on an inner circumferential surface of the second fitting cylinder. The sealing member is strongly pressed by the first fitting cylinder and the flange in the state where the first fitting cylinder is fitted into the second fitting cylinder, and where the recess and the protruding portion are fitted to each other. Due to this structure, up-and-down movement of the both fitting cylinders is limited, and the sealing member is strongly pressed, thereby maintaining sealing.