Control Valve Float Position Reduces Hydraulic Back Pressure
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Solution Overview
Problem
Existing control valve devices for mobile working machines, such as excavators, experience significant energy losses and power loss during the lifting operation due to high dynamic pressure and back pressure, which are not effectively mitigated by current designs.
Innovation Solution
Incorporating a pressure compensator and a relief valve that can be actuated into a blocking or flow position to reduce dynamic pressure, and using an adjustable safety valve to connect the lowering side of the hydraulic cylinder to the tank, thereby reducing back pressure and energy losses during lifting operations with minimal construction effort and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the control valve is actuated into the lowering position to achieve floating position, then the lifting side of the hydraulic cylinder is connected to the container, but the connection of the pump to the lowering side of the hydraulic cylinder is not deactivated and high dynamic pressure and back pressure cause energy losses
Solution Approach 1:
The invention extracts the harmful back pressure from the system by providing a separate pressure relief path. The relief valve connected to the lowering line allows pressure medium to flow directly to the tank, bypassing the control valve and eliminating the energy loss caused by high dynamic pressure during lifting operations.
Solution Approach 2:
The relief valve acts as an intermediary component that mediates between the lowering line and the tank. It provides an alternative path for pressure medium flow, relieving the back pressure that would otherwise accumulate and cause energy losses during the lifting operation.
2Loss of energy
If a relief valve is added to connect the lowering side of the hydraulic cylinder to the tank in floating position, then energy losses are reduced, but device complexity increases
Solution Approach 1:
The relief valve is designed to perform multiple functions: it relieves back pressure during lifting operations, enables proper floating position control, and can be integrated with existing control valve positions. This multi-functionality justifies the addition by providing multiple benefits from a single component.
Solution Approach 2:
The invention changes the pressure parameter in the lowering line by providing a controlled relief path. The relief valve adjusts the pressure conditions in the lowering line, allowing pressure medium to flow to the tank at controlled rates, thereby reducing back pressure and energy losses without significantly increasing system complexity.
3Use of energy by moving object
If the pump delivers minimal delivery flow in floating position, then energy efficiency is improved, but the connection of the pump to the lowering side of the hydraulic cylinder must be deactivated
Solution Approach 1:
The invention extracts the need for complex pump control by providing a passive relief path through the relief valve. Instead of requiring active pump shutdown or complex control logic, the relief valve automatically manages pressure relief, allowing the pump to operate simply at minimal flow during floating position without requiring sophisticated deactivation mechanisms.
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 solution allows for a floating position with reduced power loss and energy efficiency in lifting operations, achieved through the strategic use of existing components like pressure compensators and safety valves, which connect the hydraulic cylinder's lowering side to the tank, thereby minimizing construction and operational costs.
Implementation Method 1
a pressure compensator arranged in the connection between the delivery line of the pump and the lowering side of the hydraulic cylinder
Implementation Method 2
the lowering side of the hydraulic cylinder can be connected to the container, bypassing the control valve, with the lowering side of the hydraulic cylinder being connected to the container in the floating position by means of the relief valve
Data Source
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AI summary
The invention relates to a control valve device (SV) for controlling a double-acting hydraulic cylinder (4) of a mobile working machine, wherein the control valve device (SV) comprises a control valve (5) that throttles in intermediate positions and is connected to a delivery line (3) of a pump (1), to a reservoir line (8), to a lifting line (6a) which is connected to a lifting side (A) of the hydraulic cylinder (4), and to a lowering line (6b) which is connected to a lowering side (B) of the hydraulic cylinder (4).The control valve (5) has a neutral position (N) in which the connection of the pump line (3) and the reservoir line (8) with the lifting line (6a) and the lowering line (6b) is shut off, a lifting position (H) in which the delivery line (3) is connected to the lifting line (6a) and the lowering line (6b) to the reservoir line (8), and a lowering position (S) in which the delivery line (3) is connected to the lowering line (6b) and the lifting line (6a) is connected to the reservoir line (8).Furthermore, the control valve assembly (SV) has a float position for the hydraulic cylinder (4), wherein in the float position of the hydraulic cylinder (4) the control valve (5) is actuated to the lowering position (S), in which the lifting line (6a) is connected to the reservoir line (8), and the connection of the pump (1) to the lowering side (B) of the hydraulic cylinder (4) is deactivated, wherein a relief valve (60) is provided, by means of which the lowering side (B) of the hydraulic cylinder (4) can be connected to the reservoir (2) by bypassing the control valve (5), wherein in the float position the lowering side (B) of the hydraulic cylinder (4) is connected to the reservoir (2) by means of the relief valve (60).In order to reduce the back pressure on the lowering side (B) of the hydraulic cylinder (4) during lifting operation, the lowering side (B) of the hydraulic cylinder (4) can be connected to the reservoir (2) by means of the relief valve (60) during lifting operation of the hydraulic cylinder (4), so that the lowering line (6b) of the hydraulic cylinder (4) is connected to the reservoir (2) via the relief valve (60) and the flow of hydraulic fluid flowing out of the lowering side (B) of the hydraulic cylinder (4) flows to the reservoir (2) via the relief valve (60).