Hydraulic Pulse Unit Foam Insert for Oil Thermal Expansion
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Solution Overview
Problem
Existing power tools with hydraulic pulse units face issues with air introduction into the oil chamber due to thermal expansion, leading to impaired efficiency and complex, bulky designs, particularly when using elastic elements to compensate for heat-related expansions.
Innovation Solution
Incorporation of a compressible insert made of closed cell foam, arranged in fluid communication with the oil chamber, to accommodate thermal expansion without permanent deformation, minimizing air interference and maintaining tool efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If air is introduced into the oil chamber to accommodate thermal expansion, then the oil expansion problem is solved, but air enters the oil chamber causing impaired efficiency
Solution Approach 1:
The harmful air is extracted from the oil chamber and placed in a separate receiving space, isolated by a disc-shaped element. This allows the air to accommodate oil thermal expansion without contaminating the oil chamber, thus maintaining operational efficiency while solving the thermal expansion problem.
Solution Approach 2:
The oil chamber is segmented into two separate spaces: the oil chamber and the receiving space, divided by a disc-shaped element. This segmentation allows each space to serve its specific function independently - the oil chamber maintains pure oil for efficiency while the receiving space accommodates thermal expansion with air.
2Reliability
If elastic elements are used to compensate for heat expansion, then the pulse unit can be filled completely without air, but the design becomes more bulky and complex
Solution Approach 1:
Instead of adding complex elastic elements to the pulse unit, the solution extracts the thermal expansion function to a separate receiving space. This eliminates the need for bulky elastic elements within the pulse unit itself, maintaining a simple design while achieving complete oil filling for optimal efficiency.
3Temperature
If elastic elements are used to compensate for heat expansion, then thermal expansion is accommodated, but air enters the chamber causing impaired efficiency
Solution Approach 1:
The system is segmented into an oil chamber and a receiving space separated by a disc-shaped element. The receiving space accommodates thermal expansion with air, while the oil chamber remains free of air contamination, ensuring operational efficiency is maintained despite thermal expansion compensation.
4Temperature
If a larger compressible insert is used to accommodate thermal expansion, then thermal expansion is better managed, but the inertia and operation of the pulse unit are affected negatively
Solution Approach 1:
The thermal expansion management function is extracted from the pulse unit's rotating components and placed in a separate receiving space. This eliminates the need for large compressible inserts within the inertia drive member, preserving the pulse unit's rotational inertia and operational speed characteristics while still managing thermal expansion effectively.
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 compressible insert effectively manages thermal expansion of oil, ensuring efficient operation and reducing the risk of air introduction, thus improving tool performance and reducing complexity.
Implementation Method 1
accommodate for heat expansion of the oil as the oil heats up during operation
Implementation Method 2
the compressible insert able to accommodate for the thermal expansion of the oil by means of elastic deformation only - i.e. without permanent deformation
Implementation Method 3
as the pulse unit cools down, the oil is sucked back into the oil chamber
Data Source
Figure 1
Figure 2a~2b
Figure 3a~3b
AI summary
The present specification relates to an impulse tool comprising a motor, an output shaft, and a hydraulic pulse unit including an inertia drive member connected to the motor and rotatable about a rotation axis, an oil chamber enclosed in the inertia drive member and an impulse generating means arranged to trans fer intermittently kinetic energy to the output shaft, wherein the inertia drive member further comprises an end piece having a transverse wall, the impulse tool further comprising a disc shaped element arranged to at least partly delimit a receiving space in fluid communication with the oil chamber, formed between the disc shaped element and the transverse wall and a compressible insert arranged in fluidic communication with the receiving space, wherein the compressible insert comprises a foam body comprising a closed cell foam, and wherein the compressible insert is arranged in an insert space formed in the end piece.