Auxiliary Handle Mass-Spring Damping for Power Tool Vibration
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Solution Overview
Problem
Power tools like angle grinders experience significant vibrations due to unbalanced abrasive discs and motor-transmission assembly, leading to user discomfort and instability during operation, despite the use of auxiliary handles.
Innovation Solution
A power tool design incorporating a vibration damping assembly within the auxiliary handle, featuring mass members and elastic elements, where the natural frequency of the damping assembly is optimized to match the rotational frequency of the output shaft, reducing vibration transmission to the user.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If an auxiliary handle is added to the housing, then the user can hold the power tool with both hands to achieve relatively stable operation, but the vibration will be transmitted to the user through the auxiliary handle, which will easily cause the user's physical discomfort
Solution Approach 1:
A vibration damping assembly is introduced as an intermediary component between the auxiliary handle and the housing. This assembly includes elastic elements that absorb and dampen vibrations, preventing them from being transmitted to the user's hand while maintaining the structural connection needed for operational stability.
Solution Approach 2:
The natural frequency of the vibration damping assembly is specifically designed to match the rotational frequency of the output shaft (ratio between 0.7 and 1.3). This parameter optimization enables the damping assembly to effectively counteract vibrations at the operating frequency, reducing vibration transmission to the user.
2Ease of manufacture
If the abrasive disc has a certain amount of unbalance during rotation, then the specific structure and mounting error are unavoidable, but the unbalance causes the angle grinder to produce large vibrations during operation
Solution Approach 1:
The vibration damping assembly converts the harmful vibration energy generated by the unbalanced abrasive disc into elastic deformation energy of the spring elements. The springs absorb and dissipate this vibration energy, transforming the harmful effect into a manageable physical process that protects the user from discomfort.
3Power
If the motor and transmission assembly are used for power transmission, then the power transmission function is achieved, but vibrations are produced during motion transmission
Solution Approach 1:
The vibration damping assembly acts as a mediator between the power transmission system and the auxiliary handle. It allows the motor and transmission assembly to perform their power transmission function while intercepting and dampening the vibrations generated during motion transmission, preventing them from reaching the user.
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 vibration damping assembly effectively reduces tool vibrations, minimizing user discomfort and enhancing operational stability by aligning the natural frequency of the damping assembly with the rotational frequency of the output shaft, ensuring a better damping effect.
Implementation Method 1
The plurality of elastic elements are springs each of which connecting the mass member to the auxiliary handle
Implementation Method 2
a ratio of a natural frequency W1 of the vibration damping assembly to a rotational frequency W2 of the output shaft in rotation is greater than or equal to 0.7 and less than or equal to 1.3
Implementation Method 3
a ratio of a natural frequency W1 of the vibration damping assembly to a rotational frequency W2 of the output shaft in rotation is greater than or equal to 0.7 and less than or equal to 1.3
Data Source
AI summary
A power tool includes a housing, an auxiliary handle, and a vibration damping assembly. The auxiliary handle includes a front end and a gripping portion. The vibration damping assembly includes a mass member and an elastic element. The auxiliary handle further includes an end cap arranged at a rear end of the gripping portion where the rear end is far away from the housing relative to a front end of the gripping portion. An accommodating cavity for accommodating the vibration damping assembly is formed around the gripping portion. The elastic element is arranged between a mass member and a cavity wall of the accommodating cavity. A ratio of a natural frequency W1 of the vibration damping assembly to a rotation frequency W2 of an output shaft in rotation is greater than or equal to 0.7 and less than or equal to 1.3.