Key Cylinder Packing Insertion Axial Assembly
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Solution Overview
Problem
Existing key cylinder devices with rubber packing for play prevention have poor assembly workability due to side-surface press-fitting and require a mold without undercut portions for integrated molding of the packing insertion portion.
Innovation Solution
A key cylinder device with a packing insertion portion on the outer surface that allows vertical insertion of a packing member, featuring slip-off preventing engagement portions and a coupling portion without undercut shapes, and an inclined surface to guide the packing member into a recess, ensuring easy assembly and no undercut mold requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rubber packing is press-fitted to the outer peripheral surface of the outer cylinder in a direction along the side surface, then play prevention is achieved, but assembly workability deteriorates and the outer cylinder requires a complex shape without undercut portions
Solution Approach 1:
The packing member insertion direction is changed from the radial direction (along the side surface) to the axial direction (vertical direction). The packing insertion portion is formed with an opening on the end surface of the key cylinder, allowing the packing member to be inserted axially into a housing space and come into contact with the lock body, thereby achieving play prevention while significantly improving assembly workability
2Ease of manufacture
If the packing insertion portion is simultaneously and integrally molded with the outer cylinder, then manufacturing is simplified, but the mold requires no undercut portions which limits design flexibility
Solution Approach 1:
The packing insertion portion is designed with an axial opening on the end surface rather than a radial opening. This dimensional change allows the mold to be opened in the radial direction without encountering undercut portions, as the packing insertion portion's opening direction is perpendicular to the mold opening direction. This simplifies the molding process and reduces mold complexity while maintaining integral molding benefits
Data Source
AI summary
A key cylinder device includes a key cylinder attached inside a cylinder portion of a cylindrical mounting member and locked/unlocked by a mechanical key, and a packing insertion portion that is integrally formed on an outer surface of the key cylinder so as to have a shape without an undercut portion and includes an opening for insertion of a packing member in a vertical direction along the outer surface.