Air Tool Exhaust Pipe Thermal Isolation Design
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Solution Overview
Problem
Air tools experience cooling of the housing due to adiabatic expansion of exhaust air, leading to discomfort for users and potential hydraulic fluid leakage through gaps, which degrades working efficiency, especially in cold conditions.
Innovation Solution
The exhaust pipe is designed as a discrete member separate from the air supply/exhaust pipe accommodating part, with a clearance between them to prevent direct cooling of the housing and reduce hydraulic fluid leakage, enhancing heat insulation and rigidity while facilitating assembly and reducing pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the exhaust flow path is formed using the space between the housing and the air supply pipe, then the device complexity is reduced, but the housing is cooled by adiabatic expansion of exhaust air causing user discomfort and potential hydraulic fluid leakage
Solution Approach 1:
The exhaust flow path is segmented from the housing structure by introducing a separate exhaust pipe. The exhaust pipe is divided into a first exhaust pipe connected to the air motor and a second exhaust pipe connected to the exhaust outlet, creating distinct flow paths that prevent thermal coupling between the exhaust air and housing.
Solution Approach 2:
The exhaust pipe acts as an intermediary component between the air motor exhaust outlet and the external environment. This intermediate structure carries the adiabatically expanded cold exhaust air away from the housing, preventing direct thermal interaction while maintaining the exhaust function.
2Temperature
If the exhaust pipe is designed as a discrete member separate from the housing, then the cooling of the housing is suppressed, but the device complexity increases
Solution Approach 1:
The first exhaust pipe and second exhaust pipe are integrally formed as a single discrete member. This merging of the exhaust pipe components reduces the number of separate parts and assembly steps, offsetting the complexity increase from introducing the separate exhaust pipe structure while maintaining the thermal isolation benefit.
3Device complexity
If the air supply pipe and exhaust pipe are integrally formed, then the device complexity is reduced, but the pressure loss increases due to flow path interference
Solution Approach 1:
The intermediate portion of the exhaust pipe is designed with locally optimized geometry that specifically addresses flow interference. The exhaust flow path cross-sectional area is increased in the intermediate portion where the air supply pipe is positioned, and the exhaust pipe wall thickness is reduced in this specific region to minimize flow resistance while maintaining structural integrity elsewhere.
4Manufacturing precision
If the exhaust flow path uses the housing space, then the manufacturing precision requirements are reduced, but hydraulic fluid may leak through gaps in the housing
Solution Approach 1:
The exhaust flow path is extracted from the housing structure and relocated to a separate exhaust pipe. This extraction removes the exhaust flow path from the sealed housing environment, eliminating the risk of hydraulic fluid leakage through housing gaps while the exhaust pipe itself can be designed with appropriate sealing without compromising the housing integrity.
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 design effectively suppresses cooling of the tool housing, prevents hydraulic fluid leakage, and improves user comfort by maintaining the grip part at a warmer temperature, thus enhancing working efficiency.
Implementation Method 1
compressed air immediately after the discharge from the air motor is adiabatically expanded to lower its temperature; therefore, a part of the housing that accommodates the air motor is cooled
Data Source
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AI summary
[Technical Problem] Provided is an air tool having an exhaust pipe configured to reduce cooling of a tool housing by adiabatic expansion of exhaust air. [Solution to Problem] An air tool driven by an air motor (12) includes a tool housing (20) having an air motor accommodating part (21) accommodating the air motor (12) and a tubular air supply/exhaust pipe accommodating part (24) extending from the air motor accommodating part (21) to a rear opening end (22), and an air supply pipe (41) and an exhaust pipe (42) disposed in the air supply/exhaust pipe accommodating part (24) of the tool housing (20). In the air tool, the exhaust pipe (42) is a discrete member formed separately from the air supply/exhaust pipe accommodating part (24). In addition, a clearance is formed between the exhaust pipe (42) and the air supply/exhaust pipe accommodating part (24) to improve heat insulation between the exhaust pipe (42) and the air supply/exhaust pipe accommodating part (24).