Check Valve Bypass for Hydraulic Filter Clogging
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Solution Overview
Problem
In conventional hydraulic drive systems for working machines, filter clogging leads to high pressure in the oil passage section, risking the entire hydraulic circuit's breakdown, and the use of a relief valve to mitigate this issue is costly due to its high expense.
Innovation Solution
Incorporating a relatively inexpensive check valve in parallel with the filter in the oil passage section to direct high pressure oil to the relief valve, allowing pressure release without confining high pressure within the hydraulic circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a filter is arranged in an oil passage communicating a valve device and a relief valve to each other, then oil cleaning function is improved, but when the filter clogs, high pressure is confined in the oil passage section causing potential circuit breakage
Solution Approach 1:
A check valve is introduced as an intermediary component between the filter and the relief valve. This check valve allows pressure oil to pass through to the relief valve when the filter clogs, preventing high pressure confinement while maintaining the filter's cleaning function. The check valve acts as a mediator that resolves the conflict between filter protection and pressure relief.
Solution Approach 2:
The oil passage is segmented into multiple sections with the check valve creating a bypass path. When the filter clogs, the pressure oil can be directed through the check valve to the relief valve, effectively segmenting the pressure flow path to prevent complete system failure while maintaining the filter's cleaning function.
2Object-affected harmful factors
If a relief valve is arranged between the valve device and the filter to release high pressure, then circuit breakage is prevented, but manufacturing cost increases due to the expensive relief valve
Solution Approach 1:
The patent uses a check valve, which is a relatively inexpensive component compared to a relief valve, to achieve the pressure relief function. The check valve provides a cost-effective solution for preventing circuit breakage while maintaining the necessary pressure management functionality.
Solution Approach 2:
The check valve serves as an intermediary component that provides pressure relief functionality at lower cost. By positioning the check valve between the filter and relief valve, it enables pressure oil to bypass the clogged filter and reach the relief valve, achieving circuit protection without the high cost of relocating or replacing the relief valve.
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 configuration effectively prevents hydraulic circuit breakdown while keeping manufacturing costs low by using a cheaper check valve to manage high pressure, thus ensuring the hydraulic system's protection without increasing costs.
Implementation Method 1
a check valve arranged in the oil passage and in parallel with the filter such that a flow of oil from a side of the on/off valve toward a side of the relief valve is allowed but a flow of oil from the side of the relief valve toward the side of the on/off valve is prevented
Implementation Method 2
a filter arranged in an oil passage communicating the on/off valve and the relief valve to each other
Data Source
Figure 1
Figure 2
AI summary
[Problem] To permit guiding oil of a high pressure in an oil passage section, which communicates a valve device and a filter to each other, to a relief valve by a relatively inexpensive structure even when clogging occurs in a filter arranged in an oil passage communicating the valve device and the relief valve to each other. [Solution] A hydraulic pump (20) and a charge valve (25), to which pressure oil is fed from the hydraulic pump (20) via an oil passage (26), are arranged. Arranged in the charge valve (25) are a valve device, for example, an on/off valve (33) switchable according to pressure oil delivered from the hydraulic pump (20), a relief valve (34) specifying a maximum of switching pressure for the on/off valve (33), and a filter (36) arranged in an oil passage (35) communicating the on/off valve (33) and the relief valve (34) to each other. In the oil passage (35), a check valve (37) is arranged in parallel with the filter (36) such that a flow of pressure oil from a side of the on/off valve (33) toward a side of the relief valve (34) is allowed but a flow of pressure oil from the side of the relief valve (34) toward the side of the on/off valve (33) is prevented.