Metal-Reinforced Inner Housing for Stable Power Tool Isolation
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Solution Overview
Problem
Existing oscillating power tools face inefficiencies due to unnecessary movement of the inner housing relative to the outer housing, which affects the vibration isolation and working efficiency, especially in high temperature and humidity environments where plastic components can soften and act like spring elements.
Innovation Solution
The power tool design incorporates an elongated inner housing with a metal extending part that functions as a reinforcing rod, connected to a plastic housing, to increase the moment of inertia and reduce vibration, while the elastic connection between the inner and outer housings absorbs vibrations, and the weight is strategically placed to enhance rigidity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the inner housing is made entirely of plastic material, then the vibration isolating effect is improved, but the housing rigidity and stability deteriorate in high temperature and humidity environments
Solution Approach 1:
The inner housing is constructed as a composite structure combining plastic material and metal material. The plastic portion provides vibration isolation, while the metal reinforcing rod embedded within it provides structural rigidity and stability, especially in high temperature and humidity environments where plastic alone would soften and lose stiffness.
2Device complexity
If the inner housing is made shorter, then the device complexity is reduced, but the moment of inertia decreases causing increased unnecessary movement
Solution Approach 1:
Instead of making the entire inner housing longer, a metal reinforcing rod is strategically positioned within the plastic housing to extend the effective length and increase the moment of inertia. This localized reinforcement provides the necessary stability without requiring the entire housing structure to be more complex or longer.
3Volume of moving object
If the plastic housing extends rearward, then the housing can accommodate more components, but the housing acts like a spring element reducing vibration isolation
Solution Approach 1:
The rearward extending portion of the housing is constructed as a composite of plastic and metal materials. The plastic provides the necessary volume and flexibility for component accommodation, while the embedded metal reinforcing rod prevents the plastic from acting like a spring element, thereby maintaining vibration isolation effectiveness.
4Strength
If the inner housing is rigidly connected to the outer housing, then the structural strength is improved, but the vibration isolating effect is lost
Solution Approach 1:
An elastic member is introduced as an intermediary element between the inner housing and the outer housing. This elastic member provides a flexible connection that maintains structural strength while allowing relative movement to absorb vibrations, thus preserving the vibration isolating effect. The elastic member acts as a mediator that transmits necessary forces while filtering out harmful vibrations.
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 reduces unnecessary movement, maintains vibration isolation effectiveness even in high temperature and humidity conditions, and enhances the overall working efficiency of the tool accessory by stabilizing the inner housing and preventing resonance.
Implementation Method 1
The outer housing is elastically connected to the inner housing, e.g., via one or more elastomeric structures or cushions
Implementation Method 2
the inner housing is elongated to increase the moment of inertia of the inner housing around the first axis, thereby reducing unnecessary movement of the inner housing relative to the outer housing
Implementation Method 3
reduce the possibility that the second extending part will act like a spring element (e.g., in case the plastic material softens in a high temperature and/or high humidity environment)
Data Source
AI summary
A power tool includes a spindle, a motor, an inner housing and an outer housing elastically connected to the inner housing. The inner housing is formed by a first inner housing portion formed of metal connected to a second inner housing portion formed of synthetic polymer. The first inner housing portion includes a housing part disposed in a front part of the outer housing, and a first extending part extending rearward from the housing part and disposed in a grip part of the outer housing. The second inner housing portion includes a second extending part that has a tubular shape and at least partially surrounds the first extending part, and a rear end part connected to the second extending part and disposed in a rear part of the outer housing. The first extending part extends rearward of a center of the second extending part in the front-rear direction.