Hydraulic Displacement Pump Valve Plate for Noise Reduction
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Solution Overview
Problem
Swashplate type hydraulic displacement pumps produce noise due to high pressure differentials between piston chambers and plenums during transitions, leading to operational noise.
Innovation Solution
A hydraulic displacement pump with movable valve plates that shift forward or rearward relative to the pistons, altering the land area and slope to pre-compress or de-compress fluid, reducing pressure differentials and eliminating noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the pump operates with fixed valve plates and pistons, then the structure is simple and reliable, but high pressure differentials cause operational noise
Solution Approach 1:
The movable valve plate performs preliminary action by pre-compressing fluid in the piston chamber before the piston reaches the land portion, and de-compressing fluid after the piston passes the land portion. This preliminary pressure adjustment eliminates the sudden pressure differential that causes noise when the piston transitions between plenums, while maintaining the basic fixed-plate structural simplicity.
Solution Approach 2:
The valve plate is made dynamic rather than fixed, allowing it to move forward or rearward relative to the rotating piston carrier. This dynamic adjustment enables the valve plate to continuously optimize the timing of pressure equalization, reducing noise throughout the operational cycle while adding only minimal mechanical complexity through a simple movable connection.
2Productivity
If the pump runs at constant speed, then the operation is stable, but the output cannot be varied
Solution Approach 1:
The pump output is varied by changing the angular position parameter of the movable valve plate relative to the piston carrier, rather than changing the rotational speed. By adjusting the valve plate's angular position, the timing and duration of fluid compression and decompression are modified, which directly controls the volumetric output while keeping the rotational speed constant and simple.
3Object-affected harmful factors
If the land area of the valve plate is reduced, then noise is reduced, but the pump output is also reduced
Solution Approach 1:
Instead of simply reducing the land area, the movable valve plate performs preliminary compression and decompression actions that prepare the fluid pressure before the piston reaches the land portion. This allows the land area to remain sufficiently large for maintaining pump output while the preliminary pressure adjustments prevent sudden pressure differentials and associated noise.
Data Source
Figure 1
Figure 2A~2B
Figure 2C~3
AI summary
An hydraulic displacement pump, comprising: a pump casing including first and second opposing end housing elements; an axle extending into the pump casing; a piston carrier rotationally connected to the axle, wherein the piston carrier comprises a pressure chamber therein; and first and second opposing pistons arranged on a respective floating piston plate and being arranged within the piston carrier, wherein the first and second pistons are arranged to be driven into and out of the pressure chamber in response to rotation of the piston.