Fan Casing Air Inlet Offset for Noise Leakage Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Image forming apparatuses face challenges in suppressing fan noise due to rotation noise leakage through air inlet ports, which affects the overall noise levels within the housing.
Innovation Solution
The configuration of the fan includes a casing with a first wall, a second wall, and a peripheral wall, where the second wall is closer to the side cover, and the outside air inlet is positioned differently from the air inlet port, allowing the casing and surrounding walls to block most of the leaked noise, preventing it from escaping through the outside air inlet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the air inlet port is positioned in the conventional location (aligned with outside air inlet), then air intake efficiency is improved, but rotation noise leaks more easily to the outside
Solution Approach 1:
The patent repositions the air inlet port from a conventional aligned position to an offset position in the radial direction relative to the outside air inlet. This dimensional change in port positioning creates a spatial separation that blocks noise propagation paths while maintaining air intake functionality through the offset configuration
2Device complexity
If the outside air inlet and air inlet port are aligned, then air flow path is simplified, but noise from the impeller leaks through the air inlet port to the outside
Solution Approach 1:
The patent introduces asymmetric positioning where the air inlet port is offset from the outside air inlet in the radial direction. This asymmetric configuration breaks the direct alignment that would allow noise to propagate straight out, creating a more complex but effective noise blocking path while maintaining functional air flow
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 configuration effectively reduces noise leakage from the fan, resulting in suppressed noise levels within the image forming apparatus housing.
Implementation Method 1
the rotation of the impeller generates a low-pressure region at an inner peripheral side of the impeller
Implementation Method 2
most of the leaked rotation noise is easily blocked by the casing and the wall surrounding the outside air inlet
Data Source
AI summary
A fan introduces air and send the air toward an air blow target. The fan includes an impeller and a casing. The casing includes a first wall covering the impeller, a second wall covering the impeller and facing the first wall, and a peripheral wall surrounding the impeller and connecting the first and second walls. The peripheral wall has an air discharge port for discharging air toward the air blow target. The impeller is located between the first wall and the second wall. The second wall is located closer to a side cover than the first wall is. At least the first wall or the second wall has an air inlet port for introducing air into the casing. The outside air inlet is located at a different position from the air inlet port as viewed from a facing direction in which the fan and the side cover face each other.