Rack Guide Plug Thread Interference Design
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Solution Overview
Problem
Existing rack guide devices require complex manufacturing processes due to methods like pre-clinching and post-clinching to prevent slipping, which involve plastically deforming external thread ridges and do not facilitate efficient assembly.
Innovation Solution
A rack guide device with a plug having external threads with interference portions at the root that interfere with the internal threads, increasing frictional resistance and eliminating the need for clinching, thereby simplifying the manufacturing process by forming these interference portions during casting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If clinching methods (pre-clinching or post-clinching) are used to prevent slipping, then the holding force is improved, but the manufacturing process becomes complex
Solution Approach 1:
The invention applies local quality by creating interference portions only at specific locations (root portions of external threads) rather than modifying the entire thread structure. This localized interference design provides the necessary holding force while avoiding complex global modifications to the thread geometry, thereby simplifying the manufacturing process.
Solution Approach 2:
The interference portions are formed in advance during the casting process itself, before assembly. This preliminary formation of interference features eliminates the need for subsequent clinching operations or plastic deformation steps, directly resolving the contradiction between achieving strong holding force and maintaining manufacturing simplicity.
2Reliability
If plastic deformation of thread ridges is performed to prevent loosening, then the reliability is improved, but the manufacturing complexity increases
Solution Approach 1:
The invention changes the geometric parameters of the thread structure by forming interference portions at the root portions. This parameter modification creates inherent anti-loosening capability through interference fit, eliminating the need for plastic deformation processes while maintaining or improving reliability.
Solution Approach 2:
The interference portions are self-formed during casting without requiring additional anti-loosening operations. The structure serves its own anti-loosening function through the inherent interference geometry, eliminating the need for separate clinching or deformation steps that会增加 manufacturing complexity.
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 enhances the holding force of the plug, preventing slipping and facilitating stable screwing and unscrewing operations, thus simplifying the manufacturing and assembly of the rack guide device.
Implementation Method 1
a root portion of the external threads includes an interference portion that interferes with a crest portion of the internal threads
Data Source
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AI summary
A rack guide (20) is movably housed in a housing hole (31) of a housing (30). A plug (40) is screwed to an outer opening end portion (32) of the housing hole (31). An urging member (60) is interposed between the rack guide (50) and the plug (40). External threads (44) on the outer peripheral surface of the plug (40) are screwed to internal threads (33) at the outer opening end portion (32) of the housing hole (31). The root portion (82) of the external threads (44) includes an interference portion () that interferes with a crest portion (91) of the internal threads (33) .