Rotary Impact Tool Vibration Isolation via Elastic Housing
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Solution Overview
Problem
Existing rotary impact tools suffer from significant vibration transmission to users, leading to increased hand-arm vibration (HAV) values and potential health risks, as well as inefficiencies in cooling due to direct air flow paths.
Innovation Solution
The rotary impact tool design features a motor and impact mechanism combined as a unit within a tool casing, supported by an elastic element, which decouples the inner sub-assembly from the outer housing, reducing vibration transmission and improving cooling air flow management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the motor and impact mechanism are rigidly connected to the tool housing, then structural stability is improved, but vibration transmission to the user increases
Solution Approach 1:
The tool is divided into two separate housings: an outer housing and an inner housing. The motor and impact mechanism are mounted in the inner housing, which is isolated from the outer housing by elastic elements. This segmentation allows the vibration-generating components to be physically separated from the housing that contacts the user, reducing vibration transmission while maintaining structural integrity.
Solution Approach 2:
Elastic isolating elements are introduced as intermediaries between the inner housing (containing the impact mechanism) and the outer housing. These elastic elements act as vibration dampers, absorbing and attenuating the mechanical vibrations generated during impact operations, thereby reducing the harmful vibrations transmitted to the user's hands and arms.
2Temperature
If cooling air inlet is positioned close to the motor, then cooling efficiency is improved, but exhaust air may re-enter the air inlet reducing effectiveness
Solution Approach 1:
The elastic isolating elements also serve as air barriers between the air inlet and exhaust vent. These elements physically block the path that would allow hot exhaust air to flow back into the cooling air inlet, ensuring that the cooling airflow remains efficient and effective without energy loss from recirculation.
Solution Approach 2:
The elastic isolating elements perform multiple functions simultaneously: they provide vibration isolation between the inner and outer housings, and they also act as air barriers to prevent exhaust air from entering the air inlet. This multi-functionality resolves both the vibration transmission problem and the cooling air loss problem with a single structural feature.
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 vibration transmitted to the user's hands and arms, meeting daily exposure limits for hand-arm vibration, while also enhancing the cooling efficiency by isolating the air intake and exhaust channels.
Implementation Method 1
at least one elastic isolating element is disposed between the outer housing and the inner housing, so that the inner sub-assembly is elastically isolated from the outer housing
Implementation Method 2
an elastic isolating element is disposed between the outer housing and the inner housing and extends around the inner housing in a circumferential direction, so that the inner sub-assembly is elastically isolated from the outer housing
Data Source
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AI summary
A rotary impact tool, comprising an outer housing and an inner housing at least partly surrounded by the outer housing; an motor installed in the inner housing, and an impact mechanism connected to the motor and fixedly mounted to the inner housing, to define an integrated inner sub-assembly comprising the motor and the impact mechanism; at least one elastic isolating element is disposed between the outer housing and the inner housing and extends circumferentially around the inner housing, so that the inner sub-assembly is elastically isolated from the outer housing. According to the present invention, the motor and the impact mechanism are combined to form an independent, integrated inner sub-assembly, which is held in a tool casing by means of the elastic element alone, thereby reducing the vibration suffered by the user from the impact mechanism and motor of the rotary impact tool.