Swing Bridge Coupling for Noise Reduction in Electric Shavers
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Solution Overview
Problem
Existing oscillating bridges in small electrical devices, such as electric dry shavers, face challenges in optimizing material properties for different load areas, leading to compromises in service life, noise, and manufacturing tolerances, particularly at the coupling where wear resistance and low tolerances are crucial for minimizing noise.
Innovation Solution
A two-part design is adopted where the coupling is made of a different material, such as polyoxymethylene (POM), optimized for minimal manufacturing tolerances and sliding properties, while the oscillating body and arms are made of polyamide (PA) for improved elasticity and service life, with the components being inseparably connected through material deformation or welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the oscillating bridge is made of a single material to simplify manufacturing, then manufacturing complexity is reduced, but the service life and noise performance are compromised due to inability to optimize different areas for their specific load requirements
Solution Approach 1:
The oscillating bridge is divided into two separate components: a coupling element and an oscillating body. This segmentation allows each component to be manufactured from materials optimized for their specific functional requirements, with the coupling element made from wear-resistant material with tight tolerances and the oscillating body made from elastic material for load resistance, thereby resolving the contradiction between manufacturing simplicity and service life.
Solution Approach 2:
The invention employs composite construction by combining two different materials in the oscillating bridge assembly - the coupling element uses material with high wear resistance and low water absorption (such as POM) while the oscillating body uses material with high elasticity and load cycle resistance (such as polyamide). This composite approach allows optimization of each area for its specific load conditions, improving overall service life and noise performance.
2Object-affected harmful factors
If the coupling area is designed with tight manufacturing tolerances to reduce noise, then noise level is minimized, but the manufacturing complexity and cost increase
Solution Approach 1:
The coupling element is designed with locally optimized quality features including tight manufacturing tolerances specifically in the contact areas with the drive mechanism, while other areas can have relaxed tolerances. The coupling element incorporates guiding surfaces and articulation points with precise dimensional control to minimize play and noise, while the overall component can be manufactured with standard tolerances, balancing noise reduction with manufacturing feasibility.
3Reliability
If the oscillating bridge components are made as separate parts to optimize material properties, then service life and noise performance are improved, but the device complexity increases
Solution Approach 1:
The coupling element and oscillating body are designed to be inseparably connected through material deformation processes such as welding or ultrasonic bonding, creating a permanent joint that eliminates the need for additional fastening components. This merging approach maintains the material optimization benefits of separate manufacturing while minimizing the increase in device complexity by avoiding additional assembly hardware.
Solution Approach 2:
The connection between the coupling element and oscillating body is achieved through parameter changes in the material state during assembly, such as heating for welding or applying controlled deformation forces. This allows the components to be joined inseparably through material property changes rather than mechanical fastening, reducing the number of parts and assembly complexity while maintaining the service life benefits of material-optimized separate manufacturing.
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 minimizes noise and maximizes service life while allowing for easier production and assembly, ensuring optimal load adjustment and reduced manufacturing costs, particularly suitable for small electronic devices like electric shavers.
Implementation Method 1
the two individual parts, ie the coupling and the rest of the oscillating body, are inseparably connected to one another after they have been assembled by means of material deformation
Implementation Method 2
POM is characterized, for example, by particularly good sliding properties, which are of particular advantage in the area of the coupling, in which relative movements always occur between the crank-like or eccentric-like section and the corresponding guides on the oscillating bridge
Implementation Method 3
an oscillating movement is generated by the oscillating bridge, the direction of oscillation of which is perpendicular to the plane of the drawing
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to a swing bridge for converting a rotary motion into an oscillating motion in an electrical device. The housing (1) of the electrical device holds a drive mechanism (2) that is powered by rotation with a drive shaft (3) and that has a crank or cam-type section (4) and at least one coupling element (15) of the swing bridge (7). The swing bridge (7) has at least one swing arm (16) by means of which the coupling point (15) is elastically connected to the oscillating body (9). The oscillating body (9) carries a working medium (11) to be powered by oscillations and has a coupling (6) for the crank or cam-type section (4) of the drive shaft (3). The coupling (6) is formed as a separate component which is connected to the oscillating body (9).