Compact Impact Tool Gear Support for Torque and Vibration Control
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Solution Overview
Problem
Existing rotary impact tools face challenges in achieving a compact size while delivering high torque and minimizing vibration transmission to the battery pack.
Innovation Solution
The design incorporates a ring gear directly supported by clamshell housing without additional front supports, a bearing within the camshaft bore to reduce length, and a vibration isolating connection in the handle to minimize vibration transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the ring gear is directly supported by the clamshell housing without additional front supports, then the tool length is reduced and compactness is improved, but the structural strength and stability may be compromised
Solution Approach 1:
The ring gear support structure is merged with the clamshell housing itself, eliminating the need for separate front support components. The housing directly bears the ring gear, integrating support functionality into the existing structural elements and achieving compactness without sacrificing strength.
Solution Approach 2:
The clamshell housing performs multiple functions: it encloses the internal components, provides structural support for the ring gear, and maintains overall tool integrity. By making the housing multi-functional, additional support structures are eliminated while maintaining structural adequacy.
2Length of moving object
If a bearing is placed within the camshaft bore to reduce length, then the tool becomes more compact, but the manufacturing complexity and assembly precision requirements increase
Solution Approach 1:
The bearing is nested within the camshaft bore, placing one component inside another. This nested arrangement maximizes space utilization, reduces the overall tool length, and maintains compact dimensions while accommodating the bearing within the existing camshaft structure.
Solution Approach 2:
Instead of extending the tool length to accommodate support structures, the design transitions to a radial arrangement by placing the bearing within the camshaft bore. This dimensional reorganization achieves compactness in the axial direction while managing precision requirements through the bearing's integrated position.
3Force
If the hammer is biased towards the anvil with a spring, then torque delivery is improved, but the device complexity increases
Solution Approach 1:
The spring provides a dynamic biasing force that automatically adjusts the hammer's position toward the anvil. This dynamic mechanism enables effective torque delivery through controlled mechanical interaction without requiring complex control systems or multiple components.
Solution Approach 2:
The spring-loaded hammer mechanism is self-actuating, using the spring's stored energy to automatically bias the hammer toward the anvil and enable impact torque delivery without external control or additional actuation mechanisms, thereby maintaining simplicity.
4Object-affected harmful factors
If a vibration isolating connection is added in the handle, then vibration transmission to the battery pack is reduced, but the device complexity and weight increase
Solution Approach 1:
A vibration isolating connection is introduced as an intermediary element between the tool's moving components and the battery pack. This mediator reduces harmful vibration transmission while maintaining structural integrity, balancing protection needs with weight constraints.
Solution Approach 2:
The vibration isolating connection likely employs flexible or damping materials that can attenuate vibrations without adding significant weight. These flexible elements absorb and dissipate vibrational energy while maintaining a lightweight profile compared to rigid isolation structures.
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 compact impact wrench achieves high torque delivery with reduced length and weight, while effectively isolating vibrations from the battery pack.
Implementation Method 1
a spring biasing the hammer towards the anvil
Implementation Method 2
a vibration isolating connection in the handle to minimize vibration transmission
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A power tool includes a first housing portion and a second housing portion, a motor directly mounted between the housing portions with an output shaft defining an axis, and a gear assembly supported within the housing and including a ring gear directly supported by the housing portions, a pinion gear coupled for co-rotation with the output shaft, and planet gears meshed with the pinion gear and the ring gear. The power tool also includes a drive assembly operably coupled to the gear assembly with a camshaft, an anvil, a hammer configured to reciprocate along the camshaft to impart rotational impacts to the anvil, and a spring biasing the hammer towards the anvil. The ring gear includes lugs engaged with the first housing portion and the second housing portion to rotationally constrain the ring gear.