Solid Metal Bearing Bush for Fuel Metering Device
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Solution Overview
Problem
The existing fuel metering units for high-pressure fuel pumps face issues with dimensional accuracy and deformation of rolled bearing bushes, which affect the precision and wear resistance of the anchor bolt mounting, and the use of PTFE coatings is environmentally restricted.
Innovation Solution
A solid metal bearing bush with a nitrocarburized surface layer is used, manufactured through precise machining processes like turning and drilling, allowing for high accuracy and compensation of diameter differences between the anchor bolt and receptacle, enhancing sliding properties and wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If rolled bearing bushes are used, then the device complexity is reduced and ease of manufacture is improved, but the manufacturing precision and dimensional accuracy deteriorate
Solution Approach 1:
The patent changes the manufacturing parameters by transitioning from a rolled bearing bush to a solid bearing bush made of sintered metal powder. This material and process change enables achieving dimensional accuracy of 0.01mm or better, resolving the contradiction between ease of manufacture and manufacturing precision.
2Device complexity
If rolled bearing bushes are used, then the device complexity is reduced, but the reliability deteriorates due to deformation during operation
Solution Approach 1:
The patent employs sintered metal powder as a composite material that combines the simplicity of a solid bush structure with superior dimensional stability and wear resistance. This material choice eliminates deformation during operation while maintaining low device complexity.
3Reliability
If PTFE coating is applied to improve sliding properties, then the wear resistance is improved, but the environmental harm increases due to production restrictions
Solution Approach 1:
The patent converts the previously harmful PTFE coating process into a beneficial solution by using sintered metal powder with inherent low-friction properties. This eliminates environmental harm from PFOA usage while maintaining or improving wear resistance through the self-lubricating characteristics of the sintered material structure.
4Manufacturing precision
If the receptacle diameter is reduced to match the anchor bolt diameter, then the manufacturing precision is improved, but the adaptability deteriorates
Solution Approach 1:
The patent changes the dimensional parameters by allowing the receptacle to have a larger diameter than the anchor bolt, compensated by the precision of the solid bearing bush. This enables the same bearing bush design to accommodate various anchor bolt diameters, significantly improving adaptability while maintaining mounting precision through the 0.01mm accuracy of the sintered bush.
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 solution enables precise and low-wear mounting of the anchor bolt, maintaining dimensional accuracy and compensating for large diameter differences, while providing good sliding properties and high wear resistance, thus improving the performance and environmental sustainability of the fuel metering unit.
Implementation Method 1
The bearing bush, which is designed as a solid component, can also compensate for relatively large diameter differences between the diameter of the anchor bolt and the diameter of a receptacle for the bearing bush
Implementation Method 2
The usual rolled bearing bushes have a low wall thickness, so that a receptacle for the bearing bush that corresponds in diameter to approximately the diameter of the anchor bolt is required
Data Source
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AI summary
The invention relates to a fuel metering device for regulating the delivery rate of a high-pressure fuel pump of a fuel injection device for an internal combustion engine. The fuel metering device has a control valve (12) actuated by an electromagnet (10) and having a valve member (34). The electromagnet (10) has an armature (16) and an armature rod (18) and the armature rod (18) is axially movably supported in at least one bushing (52). The at least one bushing (52) is designed as a solid, one-piece metal component. The bushing (52) is preferably made of steel and the bearing surface (54) thereof, in which the armature rod (18) is supported, has a nitrocarbeurized and polished surface layer.