Axial Piston Pump Control for Quick Stop Safety
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing drive systems for hydraulically driven working mechanisms, such as those in harvesting machines, face challenges in quickly and precisely stopping the axial piston pump to zero capacity when a foreign body is detected, due to insufficient dynamics in solenoid valve actuation, which compromises operating safety.
Innovation Solution
A control valve arrangement is used to mechanically set the pivot angle of the axial piston pump to zero degrees, allowing for rapid flow direction reversal and independent quick stop and reversal operations, utilizing a limiting device controlled by multiple control valves to manage the pump capacity and flow direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solenoid valve is used to control flow direction reversal for quick stop, then the system can respond to foreign body detection, but the dynamics are insufficient to meet operating safety requirements and the pump capacity cannot be limited to zero due to tolerances
Solution Approach 1:
The patent replaces the solenoid valve (electromagnetic actuation) with a mechanically actuated control valve that directly controls the hydraulic flow. This mechanical system provides faster response dynamics and more precise control of the axial piston pump's pivot angle, enabling the pump capacity to be accurately limited to zero for safe quick stops.
Solution Approach 2:
The invention changes the control parameter from binary solenoid on/off states to continuous mechanical pivot angle control of the axial piston pump. By mechanically adjusting the pivot angle to precisely zero degrees, the system achieves accurate pump capacity control that eliminates the tolerance issues inherent in solenoid valve control.
2Loss of time
If the solenoid valve is de-energized to quickly degenerate the magnetic field for flow direction reversal, then the response time is reduced, but additional re-energizing is required to activate the neutral position
Solution Approach 1:
The patent extracts the magnetic field degradation step entirely by replacing the solenoid valve with a mechanically actuated control valve. This eliminates the need for de-energizing and re-energizing cycles, providing direct mechanical control that achieves flow direction reversal and neutral position activation in a single continuous action.
Solution Approach 2:
The invention introduces a mechanical intermediary (the control valve with manual or automated mechanical actuation) between the control signal and the hydraulic flow. This mechanical mediator provides direct, continuous control without the electrical on/off transitions required by solenoid valves, simplifying the control sequence while maintaining quick response.
3Adaptability or versatility
If the pivot angle is allowed to pass zero and become negative for flow direction reversal, then the system can reverse the hydraulic motor, but the pump capacity cannot be precisely controlled at zero
Solution Approach 1:
The patent segments the control range into distinct zones: a controlled zero-position zone for precise pump capacity control and a negative angle zone for reversal operation. The mechanically actuated control valve with limiting device maintains precise zero positioning while allowing intentional negative angle excursions when reversal is required, separating these two functions spatially and operationally.
Solution Approach 2:
The invention implements dynamic control where the pivot angle can be precisely held at zero for normal operation and quick stops, but can also be intentionally moved into the negative range for reversal. The mechanical control system provides this dynamic flexibility while maintaining precision through the limiting device that defines the zero position boundary.
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 solution ensures the axial piston pump can quickly and precisely assume a neutral position during a quick stop, preventing damage from foreign bodies and enabling safe operation by eliminating pump capacity, while also allowing for reversible operation without additional return means.
Implementation Method 1
the limiting device preferably comprises a piston-shaped element, at least one side of which is subjected to hydraulic pressure
Implementation Method 2
the piston-shaped element is subjected to hydraulic pressure on one side, while the weight of the pivoting base of the axial piston pump acts on the other side
Data Source
AI summary
A drive system for hydraulically driven working mechanisms of a working machine includes an axial piston pump, the pump capacity and flow direction of which is varied by changing the pivot angle of the axial piston pump. The drive system includes a hydraulic motor connected via a line to the axial piston pump and drivably connected to the working mechanisms, a control unit operated to set the pump capacity of the axial piston pump to zero and a control valve arrangement that is actuated by the control unit to actuate a limiting device such that the pivot angle of the axial piston pump can be mechanically set to zero degrees (0°).