Composite Inner Housing for Power Tool Vibration Isolation
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Solution Overview
Problem
Existing oscillating multi-tools face challenges in efficiently isolating vibrations, leading to reduced working efficiency and potential issues with tool accessories in high temperature and humidity environments.
Innovation Solution
The power tool design features an elongated inner housing with a metal front part and a plastic extending part, where the metal part acts as a core bar to support the plastic part, reducing the likelihood of the plastic part acting as a spring element and compromising vibration isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the inner housing is made entirely of plastic material, then the manufacturing cost is reduced and ease of manufacture is improved, but the housing may act like a spring element in high temperature and humidity environments, compromising vibration isolation and reducing reliability
Solution Approach 1:
The inner housing is constructed using composite materials: a metal front part (formed by die-casting or injection molding) combined with a plastic extending part (formed by injection molding). This composite structure allows the metal portion to provide rigidity and prevent spring-like behavior in high temperature/humidity environments, while the plastic portion maintains ease of manufacture and cost-effectiveness. The two materials work together to resolve the contradiction between manufacturability and reliability.
2Productivity
If the inner housing is elongated to increase moment of inertia, then unnecessary movement of the inner housing is reduced and working efficiency is improved, but the device complexity increases due to the need for multiple material connections
Solution Approach 1:
The metal front part and plastic extending part of the inner housing are integrally formed or firmly connected to act as a single unified structure. This merging of different materials into one composite housing component achieves the desired elongation and increased moment of inertia for improved working efficiency, while the integral formation process minimizes the complexity that would otherwise result from assembling multiple separate parts.
Solution Approach 2:
The composite structure of metal and plastic materials allows the inner housing to be elongated effectively. The metal front part provides the necessary rigidity and structural integrity for the extended configuration, enabling increased moment of inertia without proportionally increasing complexity, as the composite design is optimized during the molding process.
3Device complexity
If the plastic extending part is used without metal reinforcement, then the manufacturing process is simplified and cost is reduced, but the plastic part may soften in high temperature and humidity, acting like a spring element and reducing vibration isolation effectiveness
Solution Approach 1:
The inner housing uses a composite material structure where a metal front part is combined with a plastic extending part. The metal component provides thermal and dimensional stability in high temperature and humidity environments, preventing the housing from softening and acting like a spring element. This composite approach maintains vibration isolation effectiveness without significantly increasing device complexity, as the two materials are integrally formed or firmly connected.
Solution Approach 2:
The housing structure applies different material properties to different regions: the front part uses metal for rigidity and environmental resistance, while the extending part uses plastic for ease of manufacture. This local differentiation of material quality ensures that only the critical front portion requires metal reinforcement to prevent spring-like behavior, optimizing both vibration isolation and manufacturing simplicity.
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 effectively reduces unnecessary movement of the inner housing relative to the outer housing, enhancing the working efficiency of the tool accessory and maintaining vibration isolation even in adverse environmental conditions.
Implementation Method 1
the plastic material softens in a high temperature and/or high humidity environment
Implementation Method 2
an inner housing that houses a motor and a driving mechanism is elastically connected with an outer housing, which is designed to be held by a user
Implementation Method 3
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
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.