Gear Pump Elastic Disc Capsule Suppresses Trapping Noise
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Solution Overview
Problem
Fluid delivery devices with meshed external gears suffer from high noise and aeration due to the trapping phenomenon, where pressure ripples and cavitation occur due to the meshing of gears, leading to vibration and inefficiency, particularly in quiet environment applications like electric motor vehicles and refrigeration systems.
Innovation Solution
The implementation of a fluid-leak-tight backlash and an elastic disc capsule in a closed chamber, which seals off trapped interstices during gear meshing, absorbs or expels fluid to prevent pressure ripples and air bubble generation, creating a pressure buffer zone and reducing teeth bouncing contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If meshed external gears are used for fluid delivery, then power density and simplicity are improved, but noise and aeration increase due to trapping phenomenon
Solution Approach 1:
A communication passage is introduced as an intermediary channel connecting the trapped interstice to the discharge chamber. This passage allows controlled fluid communication that prevents pressure buildup and trapping phenomenon while maintaining the gear meshing mechanism's power density advantages
Solution Approach 2:
The backlash clearance parameter is optimized to a specific range (0.02-0.05mm) that balances two functions: allowing sufficient fluid communication to prevent trapping while maintaining smooth gear meshing operation. This parameter change resolves the contradiction between power transmission and noise reduction
2Ease of operation
If large backlash is used for smooth gear meshing, then ease of operation is improved, but pressure transmission between chambers increases causing noise and vibration
Solution Approach 1:
The solution applies local quality by creating a localized communication passage at the specific location of the trapped interstice. This localized feature allows fluid communication only where needed, preventing pressure transmission through the general backlash while maintaining smooth meshing operation
Solution Approach 2:
The communication passage replicates the fluid communication function that would otherwise occur through large backlash, but in a controlled manner. It copies the pressure equalization effect while eliminating the uncontrolled pressure transmission and vibration
3Object-affected harmful factors
If backlash is sealed to prevent pressure transmission, then noise and vibration are reduced, but smooth gear meshing operation may be compromised
Solution Approach 1:
The backlash clearance is segmented into two functional zones: a sealed zone that prevents pressure transmission and causes trapping, and a communication passage zone that allows controlled fluid flow. This segmentation allows the sealed portion to reduce noise while the passage portion maintains smooth operation
4Stability of the object's composition
If damping chambers with elastic elements are used to dampen pressure swing, then pressure ripples are reduced, but device complexity increases
Solution Approach 1:
The complex damping chamber structure with elastic elements is extracted and replaced by a simple communication passage. The passage extracts only the essential function of pressure equalization while eliminating the complex mechanical damping components
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 effectively suppresses pressure pulses, cavitation, and teeth bouncing contact, resulting in a low noise, low vibration, and high efficiency gear pump or motor operation by maintaining pressure balance and preventing fluid leakage.
Implementation Method 1
an elastic disc capsule in a closed chamber, which seals off trapped interstices during gear meshing, absorbs or expels fluid to prevent pressure ripples
Data Source
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AI summary
Fluid delivery devices using a pair of meshed external gears, in spite of no reciprocating component for fluid delivery enabling low rotational vibration, the high noise due to the trapping phenomenon, and the teeth bouncing contact due to undesired large backlash heretofore afforded in the gear manufacturing process, restrict the employments in the industrial field requiring quiet environment such as electric motor vehicles or room services. Accordingly, a gear pump or motor or a gear refrigerating compressor comprising a shaft gear and a driven gear meshed rotatably within a gear chamber formed with a housing and opposite side walls, which delivers fluids from a inlet chamber to a outlet chamber; a backlash of the meshed gears having fluid- leak-tight clearance; a closed chamber provided in a internal portion of at least a side wall; an opening provided on a side wall from which a communication passage extends to a closed chamber; and at least a elastic disc capsule contained in the closed chamber, comprising a pair of concaved elastic disc plate abutted and sealed against each other with gas inside, of which occupying volume varies elastically subject to the fluid pressure therein enabling to absorb or expel the squeezed fluid in the trapped interstice during the trapping period of the interstice, whereby the fluid entrapped in the interstices isolated by the fluid-leak-tight backlash suppressing the pressure transmission inwardly or outwardly, whereof volumetric variation during the trapping period is compensated by the compression or expansion of the elastic disc capsule, suppressing pressure pulse and air bubble generation and eliminating the teeth bouncing contact, achieving a low noise, low vibration and high efficiency gear pump or motor or refrigerating compressor.