Motor Housing Silencer Duct Layout for Compact Vacuum Cleaners
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Solution Overview
Problem
Compact cleaning devices face challenges in effectively reducing motor and blower noise while minimizing pressure loss, as existing silencing solutions are either too large or complex for mass production.
Innovation Solution
A motor housing design with angularly limited silencer ducts that split airflow into parallel paths around the blower chamber, utilizing the motor housing's volume efficiently for noise attenuation with minimal space and separate wall elements, allowing for a compact and cost-effective manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a large cavity and long outlet duct are used to achieve low resonance frequency for noise reduction, then noise attenuation is improved, but device size increases
Solution Approach 1:
The silencer duct is configured to extend in multiple directions including axially and radially from the blower chamber, utilizing three-dimensional space efficiently. This allows achieving the required duct length for low resonance frequency without increasing the overall device footprint, as the duct navigates through available volume rather than extending in a single linear direction.
Solution Approach 2:
The silencer duct is integrated within the motor housing structure, with the duct wall forming part of the housing wall. This nesting approach allows the silencer functionality to be incorporated into the existing device volume without adding separate external components, thereby reducing overall device size while maintaining effective noise attenuation.
2Object-affected harmful factors
If a long outlet duct is used to reduce noise, then noise attenuation is improved, but pressure loss increases
Solution Approach 1:
The silencer duct cross-sectional area is optimized locally along its length, with larger areas in regions where pressure loss would be significant and narrower sections where space is constrained. This variable cross-section design maintains low pressure loss by providing adequate flow area where needed while still achieving the required duct length for noise attenuation in space-constrained regions.
Solution Approach 2:
The silencer duct incorporates smooth curved transitions and rounded corners throughout its path, eliminating sharp angles and abrupt direction changes. These curved geometries reduce flow separation and turbulence, thereby minimizing pressure loss while allowing the duct to achieve its required length and configuration for effective noise attenuation.
3Object-affected harmful factors
If complex silencer systems are used to achieve high noise reduction, then noise attenuation is improved, but manufacturing complexity increases
Solution Approach 1:
The silencer duct wall is merged with the motor housing wall, forming an integrated structure where the silencer functionality is built into the housing itself. This consolidation eliminates the need for separate silencer components and reduces the number of assembly steps, thereby simplifying manufacturing while maintaining effective noise attenuation through the integrated duct structure.
Solution Approach 2:
The motor housing wall serves multiple functions: it provides structural support for the motor and blower, encloses the internal components, and simultaneously forms the silencer duct wall for noise attenuation. This multi-functionality reduces the total number of components required and simplifies the manufacturing process while achieving high noise reduction performance.
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 design achieves significant noise reduction from both the blower and motor with low pressure loss, enabling a compact and cost-effective silencing solution suitable for mass production, even in compact cleaning device designs.
Implementation Method 1
The principle of the silencer according to the invention is to provide an acoustic low pass filter, where only noise with frequencies above the resonance frequency of the filter is able to escape.
Data Source
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AI summary
A compact motor housing for housing a motor and a blower of a cleaning device and with integrated air outlet silencing. The motor housing encloses a flow passage between a flow inlet and outlet. The housing has a blower chamber fluidically connected to the flow inlet, and via first and second outlet openings also fluidically connected to at least two parallel, preferably similar, silencer ducts each being arranged in an area limited by an angle of less than 90°, seen in a view parallel with the blower and motor axis. The silencer ducts each have at least one wall between the blower chamber and the external wall of the motor housing for causing at least one flow direction bend, so as to provide a noise attenuating effect. The areas occupied by the at least two silencer ducts are non-overlapping, seen in a view parallel with the blower and motor axis. With a circular blower chamber, a compact box shaped motor housing can be provided with corner volumes available for silencer ducts.