Elastomer Coated Cam High-Pressure Pump Wear
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-pressure pumps in diesel common rail technology face increased wear and fatigue due to tribological loads, with existing surface treatments and coatings failing to ensure reliable lubrication and prevent adhesive wear, especially with poorly lubricating or low-viscosity fuels.
Innovation Solution
A high-pressure pump with a cam surface coated with an elastomer, such as silicone rubber, which provides high adhesive force and elastic deformation, ensuring permanent rotation and reducing wear by maintaining a lubricating film between the roller and cam, even under high loads and critical fuel conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hard steel cam and roller are used with a lubricating film of fuel, then the rolling contact can maintain permanent rotation, but the lubricating film may become too large causing the roller to stop rotating (aquaplaning effect) and leading to adhesive wear
Solution Approach 1:
An elastomer coating is applied to the cam surface to act as an intermediary between the hard steel roller and the fuel lubricating film. This coating maintains adhesion forces that prevent the roller from stopping (aquaplaning) while allowing the lubricating film to function, thereby preventing adhesive wear. The elastomer's high adhesion and elastic deformation properties ensure reliable rolling contact under varying fuel conditions.
Solution Approach 2:
The surface properties of the cam are changed by applying an elastomer coating with specific adhesion and elasticity parameters. This coating modifies the interaction between the cam and roller, ensuring sufficient adhesion to maintain permanent rotation while accommodating variations in fuel lubricity. The elastomer's mechanical properties (adhesion force, elastic modulus) are optimized to prevent both aquaplaning and adhesive wear.
2Strength
If surface treatments such as nitriding or coatings are applied to the cam and roller, then wear resistance is improved, but the reliability of permanent rotation and lubricating film maintenance cannot be guaranteed
Solution Approach 1:
The solution combines hard steel (for structural strength and wear resistance) with an elastomer coating (for adhesion and lubricating film management). This composite structure leverages the advantages of both materials: the steel provides durability and load-bearing capacity, while the elastomer coating ensures reliable adhesion and maintains the lubricating film, guaranteeing permanent rotation of the roller.
Solution Approach 2:
Instead of treating the entire cam and roller surfaces uniformly, the elastomer coating is applied specifically to the running surface of the cam where contact with the roller occurs. This localized application provides the necessary adhesion and lubricating film management properties exactly where needed, while the rest of the component maintains its original hard steel properties for structural integrity.
3Reliability
If the lubricating film is kept small to maintain adhesion, then permanent rotation is secured, but the protective effect against direct metal-metal contact is reduced
Solution Approach 1:
The elastomer coating serves as a mediator between the metal surfaces, allowing a sufficiently thick lubricating film to exist while maintaining adhesion through the elastomer's high adhesive properties. The coating prevents direct metal-to-metal contact even when the fuel film is thicker, as the elastomer itself provides a protective layer that deforms elastically under load.
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 elastomer coating significantly reduces adhesive wear and fatigue, ensuring reliable operation and extending the lifespan of the high-pressure pump by maintaining optimal rolling contact and preventing premature failure.
Implementation Method 1
The coating has a high adhesive force, which means that it is able to reliably drive the roller
Implementation Method 2
the coating usually only deforms elastically, i.e. it restores its original shape and is therefore not subject to direct wear
Implementation Method 3
the roller body rolls on the cam with little sliding slip
Implementation Method 4
a lubricating film, which represents a kind of protective layer against direct metal-metal contact
Data Source
Figure 1
Figure 2~3B
AI summary
The invention relates to a high-pressure pump for a fuel injection device of an internal combustion engine, comprising at least one pump piston driven by the rotation of a drive shaft about a rotary axis via a cam disposed on the drive shaft and a plunger assembly disposed on the pump piston, in a stroke motion in a substantially radial direction to a rotational axis of the drive shaft, wherein the plunger assembly comprises a roller having a roller shell surface making contact with a running surface of the cam, wherein the running surface of the cam and/or the roller shell surface at least partially has a coating comprising an elastomer. The invention further relates to a drive for a high-pressure pump, comprising a drive shaft having at least one cam and a roller disposed in a roller shoe, wherein a roller shell surface of the roller makes rolling contact with a running surface of the cam, wherein the running surface of the cam and/or the roller shell surface of the roller at least partially has a coating comprising an elastomer.