Fluid-Dynamic Bearing Overpressure System for Compressor Wear Reduction
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Solution Overview
Problem
Motor vehicle system devices face significant wear issues in their bearings due to high rotational speeds, leading to increased maintenance costs and reduced service life, especially in start-stop operations, where traditional solid friction bearings are used.
Innovation Solution
Implementing a fluid-dynamic bearing system where an overpressure source, such as a compressor or tandem pump, generates overpressure in the bearing gap, reducing wear by minimizing direct contact between bearing parts and allowing only fluid friction, thereby extending the service life and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional solid friction bearings are used in high-speed compressors, then the bearing structure is simple and easy to manufacture, but the wear is significant and service life is reduced
Solution Approach 1:
The patent applies pneumatic principles by introducing an overpressure source that supplies compressed air to the bearing gap, creating a fluid-dynamic bearing system. The overpressure air forms a protective film between the bearing parts, eliminating direct solid contact and significantly reducing wear. This transforms the bearing from a solid friction system to a pneumatic lubrication system, extending service life while managing the added complexity through integration with the compressor's existing air supply infrastructure.
Solution Approach 2:
The patent changes the physical state and pressure parameters of the air in the bearing gap. By maintaining overpressure conditions in the bearing gap through the overpressure source, the air density and pressure parameters are altered to enhance the bearing film's load-carrying capacity. This parameter change allows the bearing to operate in a fluid-dynamic regime rather than solid friction, improving reliability without requiring fundamentally different bearing materials or structures.
2Reliability
If fluid-dynamic bearings with overpressure sources are implemented, then wear is reduced and service life is extended, but the device complexity and space requirements increase
Solution Approach 1:
The patent applies multi-functionality by designing the overpressure source to serve dual purposes: it provides overpressure air to the bearing gap for wear reduction, and simultaneously supplies compressed air to the brake booster for brake assistance. This integration means that one air compression system supports both the bearing protection function and the brake function, eliminating the need for separate air sources and reducing overall system volume and component count.
Solution Approach 2:
The patent merges the bearing overpressure supply system with the brake air supply system by using a common overpressure source (compressor or tandem pump). The air flow path and pressure regulation systems are combined, so that the same compressed air infrastructure serves both the fluid-dynamic bearing and the brake booster. This merging reduces the number of separate components and optimizes space utilization in the motor vehicle system.
3Productivity
If bearings operate at very high rotational speeds greater than 100,000 r.p.m., then compressor performance is improved, but bearing wear increases significantly
Solution Approach 1:
The patent introduces compressed air as an intermediary substance between the bearing surfaces. This air film acts as a mediator that prevents direct contact between the bearing parts while the compressor runner rotates at high speeds. The overpressure source maintains this intermediary air layer, allowing the bearing to accommodate very high rotational speeds without the harmful solid friction and wear that would otherwise occur at such speeds.
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 fluid-dynamic bearing system significantly reduces wear and extends the service life of the bearing components, allowing for the use of less expensive materials and reducing the size and space requirements of the motor vehicle system device while maintaining reliability.
Implementation Method 1
an overpressure source, such as a compressor or tandem pump, generates overpressure in the bearing gap
Implementation Method 2
only fluid friction, particularly air friction takes place. In this context, the two bearing parts do not come directly into touching contact with each other
Implementation Method 3
the bearing is developed as an air bearing, in which, during operation, preferably in at least a few operating regions, only fluid friction, particularly air friction takes place
Data Source
AI summary
A motor vehicle system device having a drive assembly, to which a charging device is assigned, has a compressor having at least one compressor runner supported using at least one bearing, the bearing having a stationary first bearing part and a second bearing part that is operatively connected to the compressor runner. An overpressure source is connected to the bearing, using which an overpressure is able to be produced in a bearing gap that is present between the first bearing part and the second bearing part. The overpressure source is the compressor and/or a part of a tandem pump, which besides the overpressure also makes available low air pressure for a user of the motor vehicle system device. The invention also relates to a method for operating a motor vehicle system device.