Gradient Hardness Hydrodynamic Bearing Coating for Wear Control
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Solution Overview
Problem
In fluid machines with hydrodynamic plain bearings, excessive load can cause seizure, and the abrasion of resin coating layers leads to premature wear and reduced durability due to abrasion particles entering the cooling passage and accelerating wear in downstream bearings.
Innovation Solution
The implementation of a fluid machine design with hydrodynamic plain bearings featuring upstream and downstream bearings where the upstream coating layer has a lower hardness than the downstream layer, allowing for controlled abrasion particle hardness and reduced wear, and an integrated cooling passage that cools the bearings sequentially, eliminating the need for separate cooling and filtration systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resin coating layer is applied to the hydrodynamic plain bearing to prevent seizure under excessive load, then the bearing's load-bearing capability and seizure resistance are improved, but the coating layer is abraded by the rotating body and generates abrasion particles that accelerate wear in downstream bearings
Solution Approach 1:
The patent applies a gradient hardness structure to the resin coating layer, where the hardness varies through the thickness of the coating. The surface layer has lower hardness to reduce abrasion particles, while the underlying layer has higher hardness to prevent seizure. This parameter gradient resolves the contradiction between seizure resistance and wear prevention.
Solution Approach 2:
The patent uses a composite resin coating structure with multiple layers having different properties. The composite structure combines a soft outer layer (for low abrasion) with a hard inner layer (for seizure resistance), creating a material system that simultaneously achieves both opposing requirements.
2Temperature
If a cooling passage is added to cool the hydrodynamic plain bearing, then the bearing's temperature and thermal stability are improved, but the structure becomes more complex and additional components are required
Solution Approach 1:
The patent integrates the cooling passage directly into the housing structure that already accommodates the hydrodynamic plain bearing. By merging the cooling function with the existing housing, the system achieves effective cooling without adding separate cooling components or increasing overall structural complexity.
Solution Approach 2:
The housing structure serves multiple functions: it accommodates the bearing, provides structural support, and incorporates the cooling passage. This multi-functionality eliminates the need for separate cooling components, reducing device complexity while maintaining effective temperature control.
3Ease of operation
If the rotating body rotates in contact with the hydrodynamic plain bearing, then the bearing provides support at low speeds, but friction generates heat that requires additional cooling systems
Solution Approach 1:
The patent modifies the surface properties of the resin coating layer by creating a gradient hardness structure. The lower hardness at the surface reduces friction and heat generation during contact rotation, while the higher hardness beneath maintains load-bearing capability. This parameter modification allows low-speed support without excessive frictional heating.
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
This design enhances the durability of the motor-driven compressor by limiting wear on downstream bearings, simplifying the structure, and improving the efficiency of the cooling system, while eliminating the need for additional components like filters and separate cooling passages.
Implementation Method 1
the hydrodynamic pressure generated between the hydrodynamic plain bearing and the rotating body levitates the rotating body from the hydrodynamic plain bearing
Implementation Method 2
a cooling passage in its housing through which fluid flows to cool the hydrodynamic plain bearing
Implementation Method 3
friction generated between the hydrodynamic plain bearing and the rotating body heats the hydrodynamic plain bearing
Data Source
AI summary
A fluid machine includes a rotating body, an operation body rotated integrally with the rotating body, a housing, hydrodynamic plain bearings rotatably supporting the rotating body relative to the housing, and a cooling passage arranged in the housing. The hydrodynamic plain bearings each include a resin coating layer at a portion that is opposed to the rotating body. The hydrodynamic plain bearings include at least one combination of hydrodynamic plain bearings. Each combination includes an upstream hydrodynamic plain bearing and a downstream hydrodynamic plain bearing located at different positions in a direction in which the fluid flows through the cooling passage. The coating layer of the upstream hydrodynamic plain bearing has a lower hardness than the coating layer of the downstream hydrodynamic plain bearing.