Air-Introduction Pump Chamber Timing for Hydraulic Amplitude Reduction
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Solution Overview
Problem
Conventional pump devices experience hydraulic amplitude fluctuations leading to noise and vibration, and existing solutions fail to effectively suppress these issues while maintaining a simplified structure.
Innovation Solution
A pump device with an air introduction hole that opens immediately before the suction stroke completes and closes after it, allowing air to enter the pump chamber to reduce negative pressure and prevent backflow, featuring a trochoid rotor configuration with specific rotation angle settings for efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pump shaft rotation speed is increased to improve productivity, then the discharge amount increases, but the suction resistance increases and negative pressure becomes excessive causing cavitation and erosion
Solution Approach 1:
The air introduction hole is opened at a predetermined timing immediately before the suction stroke is completed, introducing air into the pump chamber in advance. This preliminary action reduces the negative pressure buildup during high-speed rotation, preventing cavitation and erosion while maintaining high productivity
Solution Approach 2:
Air is introduced as an intermediary substance into the pump chamber to mediate the pressure conditions. The air bubbles mix with the hydraulic oil to form foam, which reduces the overall negative pressure and prevents excessive suction resistance and cavitation at high rotation speeds
2Productivity
If the pump shaft rotation speed is increased to improve productivity, then the discharge amount increases, but hydraulic pressure fluctuation (hydraulic amplitude) increases causing noise and vibration
Solution Approach 1:
Air is introduced into the pump chamber immediately before the suction stroke completes, preliminarily reducing the negative pressure. This prevents excessive pressure differential during the pressurization stroke, thereby reducing hydraulic amplitude and the associated noise and vibration
Solution Approach 2:
The air introduction converts the harmful effect of excessive negative pressure into a beneficial foam mixture. The air bubbles absorbed in the hydraulic oil create a more compressible fluid that reduces pressure shocks and hydraulic amplitude, transforming the potential harm into a noise and vibration reduction benefit
3Object-generated harmful factors
If an inner rotor and outer rotor with a large number of teeth are used to divide discharge into smaller parts, then hydraulic amplitude is suppressed, but the size of the entire pump increases
Solution Approach 1:
Instead of increasing the number of teeth mechanically, the invention uses pneumatic intervention by introducing air into the pump chamber. The air bubbles mixed with hydraulic oil reduce the effective bulk modulus, making the fluid more compressible and thereby suppressing hydraulic amplitude without requiring a larger pump structure
Solution Approach 2:
The invention changes the physical parameter of the hydraulic fluid by introducing air bubbles, transforming it into a foam mixture. This parameter change (from pure hydraulic oil to air-oil mixture) reduces the fluid's compressibility characteristics, suppressing pressure fluctuations and hydraulic amplitude without modifying the pump's mechanical dimensions
4Object-generated harmful factors
If air is introduced into the pump chamber to reduce negative pressure and suppress hydraulic amplitude, then noise and vibration are reduced, but the structure becomes more complex
Solution Approach 1:
The pump chamber's own rotation and pressure variations serve to control the air introduction timing. The air introduction hole is positioned such that the rotating pump chamber automatically opens and closes it at the appropriate timing, eliminating the need for external valves or control mechanisms and keeping the structure simple
Solution Approach 2:
The air introduction hole serves multiple functions: it introduces air to reduce negative pressure, suppresses hydraulic amplitude through foam formation, and its timing is automatically controlled by the pump's own rotation. This multi-functionality reduces the need for additional components, maintaining structural simplicity while achieving noise and vibration reduction
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 solution effectively reduces hydraulic amplitude, noise, and vibration, while simplifying the pump device's structure and reducing the risk of cavitation and drive torque, especially at high rotation speeds and low temperatures.
Implementation Method 1
the air introduction hole is opened at a predetermined opening timing immediately before the suction stroke is completed... the negative pressure in the pump chamber can be reduced
Implementation Method 2
the gap (pump chamber) between the inner and outer teeth of both repeatedly expands and contracts, whereby the suction stroke for sucking the hydraulic oil and the pressurization and discharge stroke for pressurizing and discharging the sucked hydraulic oil are continuously repeated
Implementation Method 3
the introduced air bubbles are absorbed in the hydraulic oil to form foam... the hydraulic amplitude can be reduced
Implementation Method 4
the introduced air bubbles are gathered in a region adjacent to a recess of the inner rotor without being discharged due to centrifugal force... the air bubbles are compressed by pressure
Data Source
AI summary
The disclosure provides a pump device capable of suppressing hydraulic amplitude and reducing noise or vibration associated with hydraulic amplitude while simplifying the structure. The pump device includes: a housing which defines a suction port, a discharge port, and an accommodation chamber; and a pump unit which is arranged in the accommodation chamber and which defines a pump chamber that expands and contracts to exert a pumping action including a suction stroke and a pressurization and discharge stroke on a fluid. The housing includes an air introduction hole that is opened to introduce air into the pump chamber at a predetermined opening timing immediately before the suction stroke is completed.