Thermal Expansion Nut Runner for Secure Fastening
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Solution Overview
Problem
Existing nut runners often form gaps between bolt and nut threads, reducing the clamping force due to insufficient normal force on the threads, which affects the secure fastening of components.
Innovation Solution
A nut runner with a heating device to thermally expand the nut using electromagnetic induction and a cooling device to thermally contract the nut, ensuring close contact between the nut and bolt threads, thereby enhancing the clamping force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional nut runner is used to automatically screw-couple bolts and nuts, then labor and time are saved, but gaps form between the threads of the nut and bolt, reducing the normal force and clamping force
Solution Approach 1:
The patent applies thermal expansion parameter change by heating the nut to expand its dimensions, allowing the threads to be screw-coupled to the bolt without gaps. After fastening, the nut is cooled to contract and firmly contact the bolt threads, increasing the normal force and clamping force.
Solution Approach 2:
The patent directly utilizes thermal expansion of the nut material. The heating device heats the nut to expand its threads, enabling gap-free engagement with the bolt. Subsequent cooling causes contraction and firm contact, resolving the contradiction between automation and clamping force.
2Force
If the nut is heated to thermally expand it for screw-coupling, then gaps between threads are eliminated and clamping force is improved, but additional heating and cooling devices are required
Solution Approach 1:
The patent merges the heating device and cooling device into an integrated system within the nut runner. The heating device (including induction coil and power supply) and cooling device (including vortex tube and compressed air supply) are combined to form a unified fastening system that automatically performs thermal expansion and contraction sequences.
Solution Approach 2:
The patent replaces conventional mechanical fastening methods with thermal field methods. Instead of relying solely on mechanical force application, the system uses electromagnetic induction heating and vortex tube cooling to control the nut's thermal state, thereby controlling its dimensional state and engagement quality with the bolt.
3Temperature
If electromagnetic induction heating is used to heat the nut, then rapid and uniform heating is achieved, but power supply and induction coil components are added
Solution Approach 1:
The patent replaces conventional thermal conduction heating with electromagnetic induction heating. The induction coil generates an alternating magnetic field that directly induces eddy currents in the nut, heating it rapidly and uniformly without mechanical contact. This substitutes a thermal field method for traditional mechanical heating approaches.
Solution Approach 2:
The induction coil acts as an intermediary between the power supply and the nut. It converts electrical energy from the power supply into an alternating magnetic field, which then induces thermal energy in the nut through electromagnetic induction. This intermediary enables efficient and controlled heating.
4Temperature
If a vortex tube is used to cool the nut and thermally contract it, then close contact between threads is achieved, but compressed air supply system is required
Solution Approach 1:
The patent replaces conventional conduction cooling with vortex tube-based adiabatic cooling. The vortex tube utilizes the Joule-Thomson effect and vortex flow to separate compressed air into hot and cold streams, directing the cold stream to cool the nut. This substitutes a fluid dynamic cooling method for traditional mechanical contact cooling.
Solution Approach 2:
The patent utilizes pneumatic principles through the vortex tube and compressed air supply system. Compressed air is fed into the vortex tube, which generates a vortex flow that separates the air into high-temperature and low-temperature streams. The low-temperature stream is directed to cool the nut, achieving thermal contraction through pneumatic cooling.
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 effectively eliminates gaps between bolt and nut threads, increasing the normal force and clamping force, ensuring secure fastening of components without labor-intensive manual processes.
Implementation Method 1
an induction coil that heats the nut by electromagnetic induction using the power
Implementation Method 2
heats the nut to thermally expand the nut
Implementation Method 3
a vortex tube that separates compressed air into high-temperature air and low-temperature air to cool the nut by the low-temperature air
Implementation Method 4
cools the nut screw-coupled to the bolt to thermally contract the nut
Data Source
AI summary
A nut runner apparatus for screw-coupling a nut to a bolt, according to an exemplary embodiment of the present invention, includes a nut socket into which the nut is removably inserted, a heating device that heats the nut to thermally expand the nut, an actuating device that rotates the nut socket to screw-couple the nut thermally expanded by the heating device to the bolt, and a cooling device that cools the nut screw-coupled to the bolt to thermally contract the nut.