Valve Cover Resonator Layout for Hydraulic Pump Pulsation Control
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Solution Overview
Problem
Existing hydraulic pumps fail to effectively reduce pulsation of delivery pressure over a wide rotation speed range by merely introducing delivery pressure into the cylinder bore near the bottom dead center.
Innovation Solution
A hydraulic pump design incorporating a valve cover with a first chamber functioning as a Helmholtz resonator and a second chamber acting as an accumulator, which introduces delivery pressure through a supply passage to the cylinder bore near the bottom dead center, reducing pulsation at both low and high frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional hydraulic pump design is used, then the structure is simple and easy to manufacture, but the efficiency is low due to high friction losses and leakage
Solution Approach 1:
The pump employs a swash plate mechanism that converts rotational motion into reciprocating motion dynamically. The swash plate angle can be adjusted to optimize the piston stroke length, allowing the pump to adapt its displacement volume to match system demands, thereby improving efficiency while maintaining structural simplicity.
Solution Approach 2:
The invention changes key operational parameters by using variable displacement architecture where the swash plate angle determines the piston travel distance. This allows the pump to operate at optimal efficiency points by adjusting displacement based on system pressure and flow requirements, reducing energy losses.
2Power
If the pump operates at high pressure, then the power output increases, but the friction losses and leakage increase proportionally more
Solution Approach 1:
The variable displacement mechanism allows the pump to dynamically adjust its output characteristics. At high pressure conditions, the swash plate angle can be reduced to decrease displacement and maintain optimal speed-pressure relationships, preventing excessive friction losses and leakage that would otherwise occur at constant high displacement operation.
Solution Approach 2:
The invention enables parameter optimization by adjusting displacement volume based on operating pressure. This ensures the pump operates within efficient performance envelopes, reducing the proportionate increase in friction losses and leakage that typically accompanies high-pressure operation in fixed-displacement pumps.
3Loss of energy
If the pump runs at variable speeds to match demand, then energy efficiency improves, but the flow and pressure become unstable
Solution Approach 1:
The swash plate mechanism provides dynamic control over piston displacement, enabling the pump to maintain stable flow and pressure outputs even when operating speeds vary. By adjusting the swash plate angle in response to speed changes, the system compensates for speed variations and maintains operational stability.
Solution Approach 2:
The invention changes the displacement parameter dynamically to compensate for speed variations. This ensures that flow and pressure remain stable despite changes in rotational speed, allowing energy-efficient variable speed operation without sacrificing output stability.
4Device complexity
If fixed displacement architecture is used, then the structure is simple, but the energy efficiency deteriorates under varying load conditions
Solution Approach 1:
The pump incorporates a swash plate mechanism that provides variable displacement capability within a relatively simple architectural framework. This dynamic adjustment capability allows the pump to optimize efficiency under varying load conditions without requiring complex multi-component variable displacement mechanisms.
Solution Approach 2:
The invention enables parameter optimization through adjustable displacement volume controlled by swash plate angle. This allows the pump to adapt to varying load conditions and maintain energy efficiency without significantly increasing structural complexity compared to fixed displacement designs.
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 design effectively reduces pulsation of delivery pressure across a wide range of rotation speeds, maintaining pump functionality while minimizing size increases.
Implementation Method 1
a piston (22) arranged to be movable along the axis (A) between a first position and a second position within the cylinder bore (21)
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A hydraulic pump (1) includes: a valve plate (6) including a suction port and a delivery port; a valve cover (7) to which the valve plate (6) is mounted; and a cylinder block (2) that slides on the valve plate (6). The valve cover (7) includes a suction passage and a delivery passage. The valve cover (7) includes: a first chamber (8) that communicates with the delivery passage through a communication passage (81) and functions as a Helmholtz resonator; and a second chamber (9) that communicates with the delivery passage, or with the first chamber (8), through an introduction passage (91) including a restrictor (92). In the valve cover (7) and the valve plate (6), a supply passage (93) extends from the second chamber (9) to a bottom dead center-side sealing surface (64) of the valve plate (6), the bottom dead center-side sealing surface (64) being a surface located between the suction port and the delivery port. The supply passage (93) includes a restrictor (94).