Integrated Collar Bolt Assembly for Faster Threaded Fastening
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Solution Overview
Problem
Conventional fastening methods require multiple steps and increased costs due to the need for collar insertion and bolt fastening, and the use of adhesives in carbon fiber-reinforced resin materials, which complicates efficient production and increases costs.
Innovation Solution
An external thread member with a collar integrally assembled into the shaft portion, featuring a tubular and flange design that automatically fits into the mounting hole, reducing the number of parts and steps in the fastening process, and accounting for thermal expansion differences to prevent stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a collar is mounted into a mounting hole and a bolt is inserted to fasten the mounting member, then the fastening operation can be performed, but two steps including collar insertion and bolt fastening are required, making the operation time-consuming
Solution Approach 1:
The collar is integrally assembled into the shaft portion of the external thread member, merging two separate components (collar and bolt) into a single integrated fastening member. This eliminates the need for separate collar insertion and bolt fastening steps, reducing operation time while maintaining fastening functionality
2Device complexity
If the collar is bonded to the mounting hole using adhesive, then the number of parts can be reduced, but curing time is required making efficient production difficult
Solution Approach 1:
The collar is pre-assembled into the shaft portion during manufacturing, forming an integrated external thread member before use. This preliminary assembly eliminates the need for adhesive bonding and curing time during production, while maintaining the reduced parts count benefit
3Device complexity
If the collar is insert-molded into the mounting member, then the number of parts can be reduced, but a new mold is required increasing cost
Solution Approach 1:
The collar and shaft portion are assembled as separate components that form an integrated external thread member, avoiding the need for specialized insert-molding tools and new molds. This approach reduces parts count while maintaining cost-effectiveness through conventional assembly methods
4Manufacturing precision
If the axial length of the tubular portion is exactly equal to the sum of mounting hole length and counterbore hole depth, then the collar fits precisely, but thermal expansion differences cause stress in the mounting member
Solution Approach 1:
The axial length of the tubular portion is designed with a specific relationship to mounting hole and counterbore hole dimensions, accounting for thermal expansion differences. This parameter adjustment allows the collar to accommodate thermal stress while maintaining precise fit and preventing stress concentration in the mounting member
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 solution enables efficient fastening without increasing the number of parts and reduces thermal stress, simplifying the fastening operation and production process.
Implementation Method 1
an axial length of the tubular portion inserted into the mounting hole of the collar is larger than a sum of an axial length of the mounting hole and a depth of the counterbore hole by an amount corresponding to a difference between an amount of elongation of the collar and an amount of elongation due to thermal expansion of the mounting member and the fastening member at a highest temperature of an expected service environment
Data Source
AI summary
An external thread member capable of performing a fastening operation efficiently without increasing the number of parts by assembling a collar into the external thread member. The external thread member 1 includes a shaft portion 5 inserted into a mounting hole 105 of a mounting member 101 through a collar 7, and the mounting member 101 is fastened to a fastening member 102. The shaft portion 5 includes a threaded portion 51 and a neck portion 52. The collar 7 is mounted on the neck portion 52 so as to be rotatable relative to each other and is engaged with the threaded portion 51 whereby retention is achieved. A counterbore hole 106 is formed in an opening close to the mounting hole 105 of an internal thread hole 104 with a tubular portion 71 inserted into the mounting hole 105 of the collar 7.