Hydraulic Damper Bladder Core Design for Friction Reduction
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Solution Overview
Problem
Existing hydraulic dampers in discharge-side passages of hydraulic pumps face challenges in achieving a high hydraulic pressure variation absorbing effect with a small volume due to significant hysteresis loss from friction.
Innovation Solution
A hydraulic damper design featuring a cylindrical bladder with a spherical closed end and an open end having an annular flange, combined with a core and plug structure that minimizes frictional engagement and includes an air chamber to enhance pressure resistance and absorption efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the diaphragm is supported by the body along its outer periphery, then the diaphragm can be elastically deformed according to discharge pulsation, but the outer periphery of the diaphragm scrapes against the body causing large hysteresis loss due to friction
Solution Approach 1:
The invention extracts the frictional contact between the diaphragm and body by introducing a core that the diaphragm fits onto. The diaphragm is now supported by the core rather than scraping against the body, eliminating the harmful friction while maintaining elastic deformation capability for absorbing discharge pulsation.
Solution Approach 2:
The core acts as an intermediary element between the diaphragm and the body. The diaphragm fits onto the core's large-diameter portion, which is sealed in the liquid-tight manner, allowing the diaphragm to deform elastically without direct contact with the body, thus preventing frictional hysteresis loss.
2Reliability
If the diaphragm is elastically deformed to absorb hydraulic pressure variation, then damper effect is achieved, but the volume of the damper increases
Solution Approach 1:
The invention uses a bladder made of elastic material as a flexible shell that can be elastically deformed by discharge pulsation. This flexible bladder replaces rigid structures, allowing the damper to absorb hydraulic pressure variations effectively while maintaining a compact volume.
Solution Approach 2:
The core is inserted into the bladder, and the plug is disposed at the open end portion of the bladder. This nested arrangement allows multiple functional components to be compactly integrated, achieving effective hydraulic pressure absorption in a small volume.
3Reliability
If the open end portion of the bladder is sealed with a core, then liquid-tight sealing is achieved, but friction occurs between the bladder and core
Solution Approach 1:
The core has different diameter portions with specific functions: the large-diameter portion provides liquid-tight sealing by fitting into the bladder's open end, while the small-diameter portion extends into the bladder to prevent buckling. This local differentiation allows sealing without excessive friction, as only the large-diameter portion contacts the bladder for sealing purposes.
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 allows for effective absorption of hydraulic pressure variations with minimal hysteresis loss, achieving a great damper effect in a compact form while ensuring the air chamber functions as an air spring to increase pressure resistance.
Implementation Method 1
the bladder is elastically compressed and deformed toward the air chamber according to the discharge pulsation (hydraulic pressure variation on the high-pressure side)
Implementation Method 2
the air chamber functions as an air spring and contributes to increase in pressure resistance of the bladder
Implementation Method 3
the inner surface of the cylindrical portion of the bladder may come in contact with the small-diameter portion of the core in response to the external pressure so as to restrict buckling deformation of the cylindrical portion of the bladder
Data Source
AI summary
A hydraulic damper disposed in a discharge-side passage of a hydraulic pump comprises a bladder made of elastic material and formed into a cylindrical shape, a core, and a plug. The bladder includes a spherical closed end portion at its one end and an open end portion at its the other end. The open end portion includes an annular flange portion extending outwardly in the radial direction. The core includes an inserted portion to be inserted into the bladder and an annular flange portion extending outwardly in the radial direction so as to contact with an end face of the open end portion of the bladder. The inserted portion has a large-diameter portion, a small-diameter portion and a gradually-changing diameter portion formed between the large-diameter portion and the small-diameter portion and forming an air chamber in the bladder together with the small chamber.