Impact Tool Venting for Uniform Pressure and Cooling
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Solution Overview
Problem
Conventional impact tools experience heat generation and reduced operation efficiency due to uneven pressure distribution in the air chamber, leading to friction and tilting of the piston and impact element, which increases friction resistance and decreases operating speed.
Innovation Solution
The impact tool features multiple vent holes arranged along the circumference of the cylinder, allowing for uniform air pressure management by discharging and introducing air through these holes, preventing pressure differences and reducing friction, while an air introducing port enhances cooling by introducing air into the housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single vent hole is provided to allow air communication between the air chamber and outside, then the structure is simple, but pressure difference is generated in the air chamber causing piston and impact element tilting
Solution Approach 1:
The single vent hole is segmented into multiple vent holes (first vent hole and second vent hole) arranged at different positions around the cylinder. This segmentation allows air to enter/exit at multiple locations simultaneously, equalizing pressure distribution across the air chamber and preventing piston tilting while maintaining structural simplicity.
Solution Approach 2:
Different vent holes are positioned at specific locations (e.g., first vent hole at upper side, second vent hole at lower side) to address local pressure imbalances. Each vent hole serves a specific spatial zone, ensuring uniform pressure distribution throughout the air chamber during piston reciprocation.
2Reliability
If piston and impact element reciprocate while pressed against cylinder inner surface, then sealing is improved, but friction heat is generated reducing operation efficiency
Solution Approach 1:
By providing multiple vent holes at different positions, the air chamber maintains uniform pressure distribution, creating an equipotential pressure field. This prevents localized high-pressure zones that would press the piston and impact element against the cylinder wall, reducing friction heat while maintaining adequate sealing through balanced pressure.
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 maintains uniform pressure, reduces heat generation, and minimizes friction resistance, thereby enhancing the operating efficiency and cooling of the impact tool, preventing a decrease in processing speed and efficiency.
Implementation Method 1
a plurality of vent holes 50A, 50B are formed along a circumferential direction of the cylinder 20. At least two of the vent holes 50A, 50B are arranged so that one of the vent holes 50A, 50B is located at a center of one half of a periphery of the cylinder 20 and the other vent hole is located in the other half of the periphery of the cylinder.
Implementation Method 2
an air introducing port which is configured to aglow the air to flow in the housing, is provided at a position in front of a rear end of the cylinder in the housing
Data Source
Figure 1
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AI summary
A hammer drill includes, in a cylinder (20) accommodated in a housing (10), a piston (40) configured to advance and retract and an impact element (30) to operate together with the piston (40) with an air chamber (21) interposed therebetween, and a bit (B) mounted in a front part of a tool main body so that an impact operation can be transmitted to the bit (B) by advancing and retracting movement of the impact element (30). Vent holes are provided in the cylinder (20) to discharge air in the air chamber (21) to outside of the cylinder (20), and to introduce the air outside the cylinder (20) into the air chamber (21) by the movement of the piston (40). One of vent holes (50A) is located at a center of an upper half of a periphery of the cylinder (20) and the other vent hole (50B) is located in a lower half of the periphery of the cylinder (20).