Swash Plate Pump Control for Lower Starting Torque
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Solution Overview
Problem
Hydraulic pumps face high starting torque requirements due to the need to overcome the biasing force of the swash plate, which increases energy consumption and complexity, especially when transitioning from maximum to minimum displacement positions.
Innovation Solution
A control system for hydraulic pumps that includes a control piston and valve assembly, allowing the swash plate to move from maximum to neutral positions using system pressure, reducing the need for high initial solenoid current and incorporating fail-safe options for both minimum and maximum displacements, enabling efficient displacement control and reduced starting torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the swash plate is biased toward the maximum displacement position, then the pump can provide maximum hydraulic pressure and flow when needed, but the starting torque requirement increases due to the biasing force that must be overcome
Solution Approach 1:
The control valve is pre-configured with a pilot pressure chamber that can be selectively pressurized before swash plate movement. This preliminary action stores potential energy in the compressed spring and pressurized fluid, ready to assist in overcoming the biasing force during startup, thereby reducing the motor torque requirement while maintaining the ability to achieve maximum displacement when needed
2Measurement precision
If a control system is added to manage swash plate displacement, then displacement control precision improves, but the device complexity increases
Solution Approach 1:
The control valve utilizes the pump's own system pressure from its output to control the swash plate position, eliminating the need for external control systems. The pilot pressure chamber and spring work together to automatically regulate displacement based on system conditions, achieving precise control without adding complex external components
Solution Approach 2:
The control valve performs multiple functions: it regulates swash plate displacement, utilizes system pressure for control, provides fail-safe operation through spring biasing, and enables both minimum and maximum displacement positions. This multi-functionality reduces the need for separate control components, thereby managing complexity while maintaining precision
3Ease of operation
If high solenoid current is used to overcome the biasing force during startup, then the swash plate can transition to the minimum displacement position, but energy consumption increases
Solution Approach 1:
The system uses hydraulic pressure from the pump's own output, stored in the pilot pressure chamber, to assist the solenoid in moving the swash plate during startup. This hydraulic assistance reduces the electrical energy requirement for the solenoid by providing mechanical force through pressurized fluid, thereby enabling swash plate transition with lower energy consumption
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 control system reduces the electric current required at start-up, decreases energy and torque needs, and allows for convenient operation by using pilot pressure for displacement control, enabling efficient and flexible pump operation with reduced space requirements.
Implementation Method 1
a second piston end adapted to receive a displacement control force generated by a control pressure that acts on the second piston end of the control piston
Implementation Method 2
a biasing force from the swash plate
Data Source
AI summary
A hydraulic pump system includes a pump control system operable to reduce electric current required at the start of the pump and reduce starting torque for the pump. The pump control system can include a gap between a spring seat and a valve spool such that the valve spool need not overcome a biasing force from a swash plate when the swash plate changes from its maximum displacement position to its neutral position.