Resin Frame Threaded Boss Flexing for Sheet Metal Assembly Precision
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Solution Overview
Problem
Image-forming devices face challenges in achieving high positioning precision due to the low stiffness of resin frames, which can lead to warpage and reduced accuracy when combined with sheet metal frames having different coefficients of linear expansion.
Innovation Solution
The use of a resin frame with fixing threaded bosses that allow for flexing and deformation, combined with a sheet metal frame mounted over the resin frame, enhances stiffness and positioning precision while minimizing the impact of thermal expansion differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a resin frame is used to reduce device size and improve design freedom, then compactness and design flexibility are improved, but positioning precision and structural stiffness deteriorate
Solution Approach 1:
The patent combines resin and sheet metal materials to create a composite frame structure. The resin frame provides compactness and design freedom, while the sheet metal frame enhances stiffness and positioning precision. This composite approach allows the device to achieve both small size and high positioning accuracy simultaneously.
Solution Approach 2:
The patent merges the resin frame and sheet metal frame into a unified structural system. The sheet metal frame is mounted over the resin frame, combining the advantages of both materials - the design flexibility of resin and the structural rigidity of metal - to resolve the contradiction between compactness and positioning precision.
2Manufacturing precision
If a sheet metal frame is mounted on the resin frame to improve stiffness and positioning precision, then positioning precision is improved, but thermal expansion differences cause warpage and reduce reliability
Solution Approach 1:
The patent introduces a flexible resin layer (sealing resin) between the sheet metal frame and resin frame. This flexible layer can deform to accommodate thermal expansion differences between the metal and resin components, preventing warpage and maintaining structural reliability while preserving positioning precision.
Solution Approach 2:
The patent changes the physical state and properties of the resin material by controlling its curing process. The resin transitions from a liquid state (allowing for assembly and flexibility) to a solid state ( providing structural support), with careful control of curing parameters to manage thermal expansion characteristics and prevent warpage.
3Strength
If screws are used to fix the sheet metal frame to the resin frame, then assembly strength is improved, but the rigid connection amplifies thermal expansion differences and causes warpage
Solution Approach 1:
The flexible resin layer acts as a buffer between the rigid screw connection and the frame components. It maintains assembly strength while absorbing thermal expansion stresses, preventing the rigid connection from amplifying expansion differences and causing warpage that would compromise positioning precision.
Solution Approach 2:
The resin layer serves as an intermediary substance between the sheet metal frame and the main resin frame. It mediates the connection by providing both mechanical bonding strength and flexibility to accommodate thermal expansion, resolving the contradiction between strong assembly and prevention of warpage.
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
This configuration improves the overall positioning accuracy and maintains precision by allowing the resin and sheet metal frames to absorb thermal expansion changes, preventing warpage and ensuring reliable component alignment.
Implementation Method 1
different coefficients of linear expansion
Implementation Method 2
allowing the outer peripheral wall to become capable of flexing and deforming
Implementation Method 3
fixed to the resin frame by at least one screw. The resin frame has at least one fixing threaded boss on the second surface, each fixing threaded boss having a threaded hole opened on the first surface to receive the screw
Data Source
AI summary
An image-forming device includes: a side wall unit including: a resin frame having a first surface and a second surface opposing the first surface; and a sheet metal frame that is mounted over at least a part of the first surface of the resin frame and is fixed to the resin frame by at least one screw. The resin frame has at least one fixing threaded boss on the second surface, each fixing threaded boss being located at a position corresponding to one of the at least one screw and having a threaded hole opened on the first surface to receive the screw. Each fixing threaded boss includes an outer peripheral wall and an inner peripheral wall, both of which extend from the second surface in a direction away from the sheet metal frame, tip ends of the outer peripheral wall and the inner peripheral walls being connected, the inner peripheral wall being located around the threaded hole. A recessed part is formed in each fixing threaded boss in at least a part of a portion defined between the outer peripheral wall and the inner peripheral wall, thereby allowing the outer peripheral wall to become capable of flexing and deforming.