Construction Machine Hydraulics for Brake and Operation Invalidation
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Solution Overview
Problem
Existing hydraulic systems in construction machines require a dedicated solenoid valve to invalidate operations on operation devices, which is not efficient.
Innovation Solution
A solenoid on-off valve for the slewing motor's hydraulic brake is modified into a solenoid proportional valve to invalidate operations, allowing the same valve to control both operation validation and brake application, eliminating the need for a dedicated solenoid valve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dedicated solenoid valve is used to invalidate operations on operation devices, then operation invalidation can be achieved reliably, but the device complexity increases and the system becomes less efficient
Solution Approach 1:
The solenoid on-off valve originally dedicated for brake control is made to perform dual functions: controlling the parking brake and invalidating operations on operation devices. By modifying it to a solenoid proportional valve and connecting it to both the brake release port and the pilot ports of control valves, one valve replaces what would traditionally require separate dedicated valves, reducing system complexity while maintaining reliability
Solution Approach 2:
The functions of brake control and operation validation are merged into a single solenoid proportional valve system. The valve simultaneously controls hydraulic pressure to the brake release port and provides pilot pressure to control valves, combining multiple control functions into one integrated component
2Device complexity
If the solenoid on-off valve is modified into a solenoid proportional valve to control both operation validation and brake application, then the need for a dedicated solenoid valve is eliminated, but the valve control complexity increases
Solution Approach 1:
The solenoid proportional valve is designed to simultaneously control brake application/release and operation device validation/invalidation through its dual connections - to the brake release port and to the pilot ports of control valves. This multi-functionality reduces the total number of valves while the controller manages both functions through coordinated control signals
Solution Approach 2:
The valve transitions between different operating states (open/closed positions and intermediate positions) based on control signals from the controller. By changing the valve's position parameter in response to different control signals, the system achieves both brake control and operation validation functions through a single valve's variable state
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 enables the validation or invalidation of operations and control of the parking brake without a dedicated solenoid valve, preventing excessive force on the brake and allowing for a compact design by setting the torque capacity for stationary braking.
Implementation Method 1
a second solenoid proportional valve connected to the brake release port by a secondary pressure line and connected to an auxiliary pump by a primary pressure line
Implementation Method 2
the switching valve switching from a closed position to an open position when a pilot pressure led to the pilot port of the switching valve becomes higher than or equal to a second setting value
Implementation Method 3
the brake being switched from a brake-applied state, in which the brake prevents rotation of an output shaft of the slewing motor, to a brake-released state, in which the brake allows the rotation of the output shaft, when a hydraulic pressure led to the brake release port becomes higher than a first setting value
Data Source
AI summary
A hydraulic system of a construction machine includes: control valves interposed between a main pump and hydraulic actuators; and first solenoid proportional valves connected to pilot ports of the control valves. The hydraulic system further includes: a brake for a slewing motor; and a second solenoid proportional valve connected to a brake release port of the brake by a secondary pressure line and connected to an auxiliary pump by a primary pressure line. A switching valve including a pilot port connected to the secondary pressure line by a pilot line is interposed between the auxiliary pump and the first solenoid proportional valves.