Chainsaw Oil Tank Venting With Dual Chambers to Prevent Leaks
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Solution Overview
Problem
Conventional chainsaws experience oil leaks due to high pressure in the oil tank caused by thermal expansion and tilting, which existing one-way and two-way valve systems fail to prevent effectively.
Innovation Solution
The chainsaw design incorporates a dual extension chamber system with narrow slit grooves acting as flow paths, allowing communication between the oil tank and the outer space, preventing pressure buildup and leaks by directing oil flow back into the tank when tilted or during thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a one-way valve is used to prevent negative pressure in the oil tank, then the oil pump can continuously suction oil, but the pressure in the oil tank rises when oil thermally expands causing oil leaks from the discharge port
Solution Approach 1:
The venting function is segmented into two stages: first through the narrow slit groove (0.2mm width) that allows air to escape while restraining oil, and second through the breather with two-way valve. This segmentation enables different flow control characteristics for air and oil at different pressure conditions.
Solution Approach 2:
The slit groove has a specific local quality with its narrow width (0.2mm) that creates different flow resistance characteristics compared to the breather. This local quality difference allows the system to selectively allow air passage while restraining oil under normal operating conditions.
2Ease of operation
If the chainsaw is tilted or inverted during use or transport, then mobility is improved, but oil leaks from the breather in conventional designs
Solution Approach 1:
The slit groove's narrow width (0.2mm) creates a local quality difference that exploits the viscosity of oil to prevent leakage during tilting, while still allowing air passage for pressure equalization. This local geometric constraint effectively blocks oil flow even when the chainsaw is inverted.
3Object-generated harmful factors
If a narrow slit groove (0.2mm width) is used as the first flow path, then oil is restrained from leaking while air can escape to prevent pressure buildup
Solution Approach 1:
The system changes the flow resistance parameter by using a very narrow slit groove (0.2mm width) that creates high resistance to oil flow due to viscosity effects, while still allowing air passage. This parameter change enables selective flow control based on fluid properties.
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
This design effectively prevents oil leaks from the discharge port and vent hole by regulating pressure and ensuring oil flows back into the tank, even when the chainsaw is tilted or thermally expanded, without adding new parts to the conventional chainsaw.
Implementation Method 1
a first flow path which is a slit groove lengthened in a front-rear direction and has a width in a left-right direction of approximately 0.2mm
Implementation Method 2
a first flow path which is a slit groove lengthened in a front-rear direction and has a width in a left-right direction of approximately 0.2mm
Implementation Method 3
an oil pump that sucks oil stored in an oil tank and supplies the sucked oil to a sliding portion between the guide bar and the saw chain
Implementation Method 4
a two-way valve that allows the flow in directions of discharge to and suction from the outer space
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A chainsaw that can prevent the pressure in an oil tank from becoming high or negative and prevent occurrence of oil leak, is provided. The chainsaw (1) includes a chainsaw body (10), a guide bar (20) and a saw chain (30). The chainsaw body (10) includes an oil tank (70), an oil pump (60) to supply oil stored in the oil tank (70) to a sliding portion between the guide bar (20) and the saw chain (30), a first extension chamber (71) arranged above the oil tank (70) and a second extension chamber (72) arranged above the first extension chamber (71). The oil tank (70) communicates with the first extension chamber (71) via a first flow path (81), the first extension chamber (71) communicates with the second extension chamber (72) via a second flow path (82) and a vent hole (83) communicating with the outer space is formed in the second extension chamber (72).