Compact Impact Tool: Direct Ring Gear Support for High Torque
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Solution Overview
Problem
Existing rotary impact tools face challenges in achieving a compact size while delivering high torque and maintaining operational efficiency.
Innovation Solution
The design incorporates a clamshell housing with a directly supported ring gear and a vibration isolating connection, reducing the overall length and weight, and includes a gear assembly that is directly supported by the clamshell halves without additional components, allowing for a compact yet powerful impact wrench.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If traditional rotary impact tool design is used, then sufficient torque can be delivered, but the tool size becomes large and weight increases
Solution Approach 1:
The ring gear is directly supported by the clamshell housing halves, merging the support function into the existing housing structure. This eliminates the need for separate support components and reduces overall tool length while maintaining torque delivery capability through the integrated gear assembly.
Solution Approach 2:
The gear assembly is arranged in a compact planetary configuration where the ring gear, planet gears, and pinion gear occupy overlapping radial and axial spaces. This three-dimensional arrangement allows sufficient torque generation within a reduced overall length by utilizing space in multiple dimensions rather than linear extension.
2Force
If traditional rotary impact tool design is used, then sufficient torque can be delivered, but the tool weight increases
Solution Approach 1:
The ring gear support structure is merged with the clamshell housing, eliminating redundant support components. This integration reduces the total mass of the tool while preserving the torque transmission path through the gear assembly to the anvil.
Solution Approach 2:
Unnecessary intermediate support components and excess structural elements are removed from the design. The gear assembly relies on the inherent strength of the clamshell housing for support, extracting only the essential torque-delivering components and eliminating surplus weight.
3Length of moving object
If compact design is implemented, then tool size is reduced, but structural support for gear assembly becomes insufficient
Solution Approach 1:
The structural support function is merged into the clamshell housing itself, which is designed with adequate strength to directly support the ring gear. This integration ensures that the housing serves dual purposes as both enclosure and structural support, maintaining strength while minimizing overall dimensions.
Solution Approach 2:
The clamshell housing is constructed from materials that provide high strength-to-weight ratio, enabling it to support the gear assembly loads within a compact form factor. The use of engineered materials allows the housing to achieve necessary structural integrity without increasing size or weight.
4Length of moving object
If compact design is implemented, then tool length is reduced, but device complexity increases
Solution Approach 1:
The support structure is merged with the clamshell housing, reducing the number of discrete components. This integration simplifies the overall device by eliminating separate support brackets, bearings, or mounting structures that would otherwise be required in a traditional design.
Solution Approach 2:
Redundant support components and intermediate structural elements are extracted from the design. The gear assembly is supported directly by the housing without unnecessary intermediate structures, reducing component count and simplifying assembly while maintaining compact dimensions.
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 impact wrench achieves a compact size and lightweight design while delivering at least 500 foot-pounds of fastening torque, with dimensions between 106 mm and 125 mm in length and 200 mm to 235 mm in height, and a weight of 1.9 to 2.15 pounds, enhancing ergonomics and operational capabilities.
Implementation Method 1
a spring biasing the hammer towards the anvil
Implementation Method 2
a hammer configured to reciprocate along the camshaft to impart rotational impacts to the anvil
Implementation Method 3
a gear assembly supported within the housing and operably coupled to the motor, the gear assembly including a ring gear directly supported by the first and second clamshell halves, a pinion gear coupled for co-rotation with the output shaft, and a plurality of planet gears meshed with the pinion gear and the ring gear
Data Source
AI summary
A power tool includes a housing having a motor housing portion and a handle portion extending from the motor housing portion. The motor housing portion and the handle portion are defined by cooperating first and second clamshell halves coupled together along a parting plane. A motor is supported within the motor housing portion and includes an output shaft defining an axis. A gear assembly includes a ring gear directly supported by the first and second clamshell halves, 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 has an overall length measured along the axis from a rear end of the housing to a front end of the anvil between 106 mm and 125 mm, and is capable of delivering at least 500 foot-pounds of fastening torque to a workpiece through the anvil.