Variable Displacement Vane Pump Fail-Safe Control
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Solution Overview
Problem
Existing variable displacement vane pumps lack an effective fail-safe mechanism to maintain controlled pressure when the electrical valve fails, leading to potential damage from excessive pressure and poor regulation characteristics.
Innovation Solution
Incorporating a pressure controlled valve that moves between active and inactive positions based on output pressure thresholds, allowing it to take over and control the pump's pressure when the electrical valve is disabled, ensuring the pressure remains within safe limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an electrical valve is used to control pump pressure, then pressure regulation precision is improved, but reliability deteriorates due to potential valve failure causing excessive pressure
Solution Approach 1:
The patent changes the control parameter from purely electrical to a hybrid electro-mechanical system. The pressure controlled valve responds to pressure parameter changes automatically, providing a fail-safe mechanism that maintains reliability while preserving the precision benefits of electrical control during normal operation.
Solution Approach 2:
The pressure controlled valve acts as an intermediary safety mechanism between the electrical valve and the pump system. When the electrical valve fails, the pressure controlled valve mediates by taking over pressure control functions, preventing system damage and maintaining reliability.
2Reliability
If a pressure controlled valve is added as a fail-safe mechanism, then reliability is improved, but device complexity increases
Solution Approach 1:
The pressure controlled valve is designed to be self-activating based on pressure thresholds. It automatically engages when pressure exceeds safe limits without requiring external control signals, reducing the complexity of control systems while maintaining high reliability through autonomous fail-safe operation.
Solution Approach 2:
The control system is segmented into two independent valve subsystems: an electrical valve for normal precision control and a pressure controlled valve for fail-safe operation. This segmentation allows each valve to specialize in its function, improving overall reliability while keeping individual valve designs relatively simple.
3Reliability
If the pressure controlled valve activates frequently to prevent excessive pressure, then reliability is improved, but energy consumption increases
Solution Approach 1:
The pressure controlled valve dynamically adjusts its activation threshold and response characteristics based on operating conditions. By optimizing when and how the valve activates, the system maintains reliable pressure control while minimizing unnecessary valve operations that would consume energy, thus balancing reliability with energy efficiency.
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 pressure controlled valve effectively prevents excessive pressure and maintains stable lubricant delivery, even when the electrical valve fails, enhancing the pump's reliability and regulation range while reducing the risk of damage and energy consumption.
Implementation Method 1
a resilient structure biasing the control slide towards the first slide position
Implementation Method 2
a pressure controlled valve moveable between a first valve position and a second valve position based on an output pressure of the pressurized lubricant delivered through the outlet
Implementation Method 3
an electrical valve fluidly connected to the control chamber to control pressure therein
Implementation Method 4
an outlet for delivering pressurized lubricant to the system from the housing
Data Source
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AI summary
A variable displacement vane pump has a pressure controlled valve moveable between first and at least second valve positions based on an output pressure of the pressurized lubricant delivered through the outlet. The pressure controlled valve provides an integrated fail safe function to the pump when an electrical valve fails. The pressure controlled valve is inactive in the first position for an output pressure below a threshold level, allowing an electrical valve (current, solenoid, pulse width modulation (PWM) valve) to selectively control pressure in the control chamber under normal operation of the pump. In fail safe regulation mode, the electrical valve function is disabled and the pressure controlled valve is active in its second position, controlling pressure in the control chamber. Channels and vents in the pump can be opened and closed based on selective movement of the valve when the outlet pressure is at or above a threshold level.