Sliding Lacquer Coating for Crankshaft Bearings
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Solution Overview
Problem
Existing anti-friction coatings for internal combustion engines have a limited load capacity, leading to rapid destruction and potential bearing failure due to insufficient wear resistance and resilience, especially under high loads.
Innovation Solution
A bonded coating with a binder and fillers, specifically zinc sulfide and barium sulfate in a controlled volume ratio, along with optional additional fillers, to enhance the load-bearing capacity and wear resistance, forming a multi-layer system optimized for improved operational reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If resin-based sliding coatings are used to reduce friction, then sliding properties are improved, but load-bearing capacity is limited and rapidly destroyed under high loads
Solution Approach 1:
The invention uses a composite material system consisting of a resin binder (such as PAI, PI, epoxy resin, phenolic resin, or PBI) combined with specifically selected fillers (MoS2, WS2, BN, PTFE, ceramic powders, metals, or Fe2O3). This composite structure allows the coating to maintain sliding properties while significantly improving load-bearing capacity. The resin matrix provides flexibility and adhesion, while the filler particles provide structural strength and emergency running properties, resolving the contradiction between sliding performance and load-bearing capacity.
Solution Approach 2:
The invention changes the chemical and physical parameters of the coating by selecting specific resin types and filler combinations. The binder undergoes chemical or physical cross-linking or chemical transformation during curing to form a dimensionally stable and highly resilient thin film. This parameter change enables the coating to withstand higher loads while maintaining its sliding function, directly addressing the load-bearing capacity limitation of conventional resin-based coatings.
2Reliability
If paste-like plastic layers are applied under pressure into substrate pores, then anchoring is improved, but application complexity increases and requires pressure application equipment
Solution Approach 1:
The invention replaces the mechanical pressure application system with a chemical bonding system. Instead of forcing paste-like material into pores under mechanical pressure, the low-viscosity sliding lacquer is applied by spraying or printing and then cured through chemical or physical cross-linking. This substitution eliminates the need for complex pressure application equipment while achieving reliable anchoring through chemical adhesion to the substrate.
Solution Approach 2:
The invention utilizes phase transition during the curing process. The binder transitions from a low-viscosity liquid state during application to a cross-linked solid state after curing. This phase change allows the coating to be easily applied in liquid form and then transforms into a dimensionally stable, firmly anchored film, eliminating the need for mechanical pressure application while ensuring reliable attachment to the substrate.
3Ease of manufacture
If sliding lacquer coating is applied to pre-formed sliding elements, then manufacturing flexibility is improved, but coating uniformity becomes difficult to achieve
Solution Approach 1:
The invention replaces mechanical pressure application with a self-leveling chemical process. The low-viscosity sliding lacquer is applied by spraying or printing and automatically levels itself during the curing process, forming a uniformly thick coating without requiring mechanical pressure. This substitution maintains manufacturing flexibility while achieving consistent coating uniformity on pre-formed sliding elements.
Solution Approach 2:
The invention changes the viscosity parameter of the coating material during the application and curing process. The sliding lacquer is applied in a low-viscosity state that allows easy flow and self-leveling, then undergoes curing to form a dimensionally stable film. This parameter change enables uniform coating thickness to be achieved on complex geometries without mechanical pressure, resolving the contradiction between manufacturing flexibility and coating uniformity.
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 combination of zinc sulfide and barium sulfate significantly increases the peak load capacity of crankshaft bearings, improving wear resistance and resilience, allowing for higher operational reliability by reducing wear rates and extending the load limit, comparable to aluminum-based sputter layers.
Implementation Method 1
the binder of a sliding lacquer undergoes chemical or physical cross-linking or chemical transformation into a less soluble or less meltable form
Implementation Method 2
subsequently cured thermally or under UV light
Implementation Method 3
The smooth surface formed without pressure allows the application of a uniformly thick sliding lacquer coating
Implementation Method 4
fillers that promote sliding properties... zinc sulfide and barium sulfate... significantly increases the peak load capacity... improving wear resistance and resilience
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention concerns an anti-friction lacquer (11, 12, 41, 42, 43) and anti-friction laminate (10) comprising at least 25 vol.% of a binding agent (16) and fillers comprising zinc sulphide (18) and barium sulphate (20) and optionally other fillers, the volume ratio of zinc sulphide (18) to barium sulphate (20) being between 0.1 and 15.7, preferably between 0.8 and 4.88 and most preferably between 1.5 and 3.44. The anti-friction laminate (10) comprises at least two anti-friction lacquers (11, 13) such as this and of differing compositions. The invention also concerns anti-friction laminates containing lacquers such as this and the use thereof in combustion engines.