Variable Displacement Pump Control Chamber Switching
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Solution Overview
Problem
Variable displacement pumps face the risk of unintended movement of the movable member due to pressure imbalance between the pump chamber and the control chamber, leading to uncontrollable pump operation.
Innovation Solution
Incorporating a control mechanism that allows switching between opening and closing states of the control chamber to the supply/discharge passage, preventing unintended movement by maintaining a closed state to improve controllability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the control chamber is opened to the supply/discharge passage, then the pressure control is relaxed and the movable member can move freely, but unintended movement occurs due to pressure imbalance
Solution Approach 1:
The control mechanism dynamically switches between two states: opening the control chamber to the supply/discharge passage for pressure equalization, and closing it for precise pressure control. This dynamic switching resolves the contradiction by allowing the system to have both freedom of movement when needed and stability when required.
Solution Approach 2:
The invention changes the pressure parameter in the control chamber by switching between connected and isolated states. When the control chamber is connected to the supply/discharge passage, pressure equalization prevents unintended movement. When isolated, precise pressure control enables accurate positioning of the movable member.
2Reliability
If the control chamber is closed to the supply/discharge passage, then pressure control is improved and unintended movement is prevented, but the system loses adaptability to pressure changes
Solution Approach 1:
The control mechanism provides dynamic adaptability by switching between closed and open states. The closed state maintains reliable pressure control for preventing unintended movement, while the open state allows adaptation to pressure changes in the supply/discharge passage, resolving the contradiction between reliability and adaptability.
3Ease of operation
If the control mechanism is added to switch opening/closing states, then controllability is improved, but device complexity increases
Solution Approach 1:
The control mechanism is designed to be actuated by the system's own pressure differential. When pressure imbalance occurs, the pressure difference automatically drives the control mechanism to switch states, eliminating the need for external control systems and reducing overall device complexity while maintaining improved controllability.
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 enhances the controllability of the pump by preventing unintended movement of the movable member, ensuring stable operation and efficient hydraulic oil supply.
Implementation Method 1
adjusting a pressure in a control chamber that is applied to the movable member
Data Source
AI summary
A variable displacement pump device includes a pump, a mover, a biasing member, first and second control chambers, and a controller. The first and second control chambers are provided between an inner periphery of a containing chamber of a housing and an outer periphery of the mover. Hydraulic oil is introduced from a discharge port into the first control chamber. The pump is configured to permit oil to be introduced from the discharge port into the second control chamber via a supply/discharge passage or to be discharged from inside the second control chamber. The second control chamber is located adjacent to any of the pump chambers in a discharge region or the discharge port via the mover. The controller is configured to switch states in which the second control chamber is opened and closed to the supply/discharge passage.