Hydraulic Bearing Rigidity Compensation at Low Temperatures
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Solution Overview
Problem
Hydraulic bearings experience a drop in rigidity at low temperatures due to different coefficients of expansion between the core, shell, elastomers, and working fluid, leading to pressure drops and asymmetrical stiffness curves, especially when residual air is present, which complicates volume compensation and affects bearing performance.
Innovation Solution
A compensation chamber with a movable or elastic separating element is introduced to store a compensating fluid, which can be dosed into the functional chambers to maintain rigidity, using a check valve and flow restrictor to control pressure and prevent significant pressure drops, while a gas-filled space ensures volume equalization without significant pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If residual air is absorbed in the functional chambers to compensate for volume shrinkage, then the pressure drop is reduced, but the bearing rigidity drops at low temperatures
Solution Approach 1:
The patent divides the compensation function into two separate systems: residual air in functional chambers for pressure stability and compensating fluid in a dedicated compensation chamber for volume compensation. This segmentation allows each system to perform its specific function without interfering with bearing rigidity.
Solution Approach 2:
The compensating fluid acts as an intermediary substance that transfers volume compensation from the compensation chamber to the functional chambers. This intermediary mechanism enables volume compensation without introducing large air bubbles that would reduce bearing rigidity.
2Reliability
If the working fluid cools down, then volume compensation is needed, but a hollow space is created that reduces pressure and affects stiffness
Solution Approach 1:
The compensating fluid is prepared in advance in the compensation chamber, ready to be supplied to functional chambers when volume shrinkage occurs due to cooling. This preliminary preparation ensures immediate compensation without creating harmful hollow spaces.
Solution Approach 2:
The patent uses hydraulic principles by introducing a compensating fluid through fluid-conducting connections to compensate for volume changes. This hydraulic compensation mechanism maintains pressure and stiffness more effectively than gas expansion alone.
3Reliability
If residual air is expanded by falling pressure, then volume compensation occurs, but asymmetrical stiffness curves result when different amounts of air are in functional chambers
Solution Approach 1:
The compensating fluid provides homogeneous volume compensation to both functional chambers, ensuring symmetrical stiffness characteristics. Unlike residual air that may be distributed unevenly, the compensating fluid can be uniformly supplied to maintain balanced bearing performance.
4Reliability
If the pressure drops below vapor pressure, then the working fluid evaporates to fill the cavity, but the system pressure corresponds only to vapor pressure
Solution Approach 1:
The compensating fluid counteracts pressure drops before they reach vapor pressure levels by supplying volume compensation in advance. This preliminary action prevents the working fluid from evaporating and maintains system pressure above vapor pressure.
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 minimizes the drop in bearing rigidity at low temperatures, maintains full dynamic rigidity at functional frequencies, and compensates for volume changes due to temperature fluctuations, ensuring consistent performance and reduced pressure variations.
Implementation Method 1
the different coefficients of expansion of the core, the shell, the elastomers and the working fluid take effect. The working fluid in the functional chambers usually shows a significantly higher coefficient of expansion than the surrounding, essentially hard, boundary materials.
Implementation Method 2
the compensation fluid in the compensation chamber being separated from a gas-filled space by a movable or elastic separating element
Data Source
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AI summary
A bearing (1) comprising a core (2) and a sheath (3) which surrounds said core, wherein the core (2) is supported against the sheath (3) by means of at least one elastomer (4, 5) or a plurality of elastomers (4, 5), wherein at least two functional chambers (6, 11) which contain a working fluid are formed between the core (2) and the sheath (3), and wherein the functional chambers (6, 11) are bounded at least partially by the elastomer or elastomers (4, 5), characterized, with respect to the problem of configuring a bearing in such a way that a drop in rigidity of the bearing is as small as possible at low temperatures, in that at least one equalizing chamber (7) is provided for an equalizing fluid, from which the equalizing fluid can be diverted into the functional chambers (6, 11), wherein the equalizing fluid in the equalizing chamber (7) is separated from a gas-filled space (9) or a plurality of gas-filled spaces by a movable or elastic separating element (8, 21).