Impact Driver Anvil Valve for Temperature-Stable Fluid Damping
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Solution Overview
Problem
Existing impact drivers face performance issues due to fixed set screw positions that cannot adjust to varying temperature conditions, leading to motor stalling and performance degradation, and sealed elastic tubes that can rupture under pressure changes, causing catastrophic failures.
Innovation Solution
An active valve system that adjusts fluid discharge based on fluid characteristics such as volume, temperature, and viscosity, and a design that includes a compressible bladder to accommodate volumetric changes, preventing pressure buildup and leaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed set screw is used to control fluid discharge, then the device structure is simplified, but performance consistency across temperature extremes deteriorates due to viscosity changes
Solution Approach 1:
The patent replaces the fixed set screw valve with a dynamic valve system that includes a valve member movable between sealed and open positions. This dynamic adjustment allows the valve to respond to changing fluid viscosity conditions across temperature extremes, maintaining consistent performance by adapting the discharge characteristics rather than relying on a fixed mechanical setting that cannot accommodate viscosity variations.
Solution Approach 2:
The patent utilizes temperature-dependent parameter changes by designing the valve system to automatically adjust its discharge characteristics in response to temperature and viscosity variations. The valve member's position and opening degree can be modified based on operating conditions, allowing the system to maintain optimal performance across a wide temperature range from -30°C to 215°C without requiring manual recalibration.
2Reliability
If the hammer chamber is completely sealed to contain hydraulic fluid, then fluid retention is improved, but thermal expansion causes excessive pressure buildup leading to tool stall
Solution Approach 1:
The patent incorporates a foam insert disposed within the hammer chamber that preliminarily occupies space to accommodate thermal expansion of the hydraulic fluid. This foam insert acts as a pre-configured expansion buffer that compresses as temperature increases, preventing excessive pressure buildup while maintaining fluid containment. The foam material is specifically selected to provide the necessary compressibility and thermal stability for this purpose.
Solution Approach 2:
The patent employs a foam insert that functions as a flexible, compressible element within the sealed hammer chamber. This foam structure can dynamically adjust its volume in response to thermal expansion of the hydraulic fluid, providing a flexible accommodation mechanism that prevents rigid pressure buildup while maintaining the sealed environment necessary for fluid retention.
3Ease of manufacture
If the impact assembly design is fixed, then manufacturing is simplified, but adaptability to different temperature conditions deteriorates
Solution Approach 1:
The patent introduces dynamic elements into the impact assembly, including a movable valve member and a compressible foam insert, that allow the fixed manufacturing design to adapt to varying temperature conditions. These components are integrated into the assembly in a way that requires minimal additional manufacturing steps while providing significant operational adaptability across extreme temperature ranges.
Solution Approach 2:
The patent utilizes parameter changes in the foam insert and valve system to enable the fixed impact assembly design to operate adaptively across different temperature conditions. The foam insert's compressibility and the valve member's adjustable positioning allow the system to automatically compensate for temperature-induced viscosity changes without requiring complex manufacturing variations for different temperature ratings.
4Reliability
If a traditional valve system is used, then fluid control is achieved, but the design precludes inclusion of bit ejection springs
Solution Approach 1:
The patent implements a nested design where the valve member is integrated within the existing impact assembly structure, and the foam insert is disposed within the hammer chamber in a space-efficient manner. This nesting approach allows the bit ejection spring to be positioned in the annular space between the foam insert and the hammer chamber wall, enabling all components to coexist in a compact configuration without compromising fluid control functionality.
Solution Approach 2:
The patent utilizes the annular space in a radial dimension between the foam insert and the hammer chamber wall to position the bit ejection spring. This dimensional arrangement allows the spring to be accommodated without interfering with the axial fluid control path, effectively using unused spatial dimensions to resolve the conflict between valve system requirements and bit ejection functionality.
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 active valve system maintains consistent performance across temperature variations, while the compressible bladder prevents pressure-related failures, ensuring reliable operation and extended tool life.
Implementation Method 1
The viscous fluid acts as a damper and slows down the inward motion of the blades 1016
Implementation Method 2
an impact driver includes a foam insert configured to reduce in volume upon an increase in temperature or pressure of the fluid in the hammer chamber
Data Source
Figure 1
Figure 1B~10A
Figure 2
AI summary
A power tool comprises a housing, a motor assembly and an impact assembly configured to be driven by the motor assembly. The impact assembly comprises a hammer defining a hammer chamber therein and an anvil at least partially disposed in the hammer chamber and configured to rotationally drive an output shaft. The anvil comprises a body portion, an anvil chamber defined therein, and a reciprocating member configured to selectively move radially outwardly relative to the body portion to be selectively impacted by an impact member of the hammer so that the hammer selectively imparts rotational movement to the anvil. The anvil includes an active valve configured to control discharge of fluid from an anvil chamber to the hammer chamber. The active value variably opens based on variance of one or more physical characteristics of the fluid (e.g., at least one of volume, temperature, pressure, or viscosity of the fluid).