Variable Oil Pump Slide Sinter Hardening for Wear Resistance
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Solution Overview
Problem
Existing oil pumps provide oil pressure in a straight line, leading to a 2% loss in fuel efficiency, and variable oil pumps face wear issues due to steam or nitration treatments which are not durable under severe conditions.
Innovation Solution
A method for manufacturing a slide for a variable oil pump using prealloy powder with specific compositions and an improved sinter hardening process, including slow and rapid cooling, to achieve high dimensional precision and wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If steam treatment or nitration treatment is applied to the variable oil pump slide, then wear resistance is improved, but the treatment layer peels off under severe conditions reducing reliability
Solution Approach 1:
The patent changes the chemical composition parameters of the slide material by using prealloyed powder with specific percentages of chromium (2.0-3.0%), molybdenum (0.5-1.0%), and carbon (0.7-1.0%). This compositional change enables the material to achieve high wear resistance through its inherent alloy structure rather than relying on surface treatment layers that peel off under severe conditions.
Solution Approach 2:
The patent creates a composite microstructure within the slide material by combining multiple alloying elements (chromium, molybdenum, carbon, manganese) in specific proportions. This composite material approach produces a synergistic effect where the combination of elements provides superior wear resistance and structural stability compared to single-element treatments, eliminating the peeling issue associated with surface coatings.
2Ease of manufacture
If conventional sintering method is used, then manufacturing process is simple, but dimensional precision is poor requiring additional machining
Solution Approach 1:
The patent applies preliminary action by using prealloyed powder with precisely controlled chemical compositions before the sintering process. The prealloying step ensures homogeneous distribution of alloying elements, which prevents dimensional distortion and warping during sintering. This preliminary preparation of the powder material enables direct sintering to produce parts with high dimensional precision, eliminating the need for subsequent machining operations.
3Strength
If rapid cooling is applied to the sintered body, then surface hardness is improved, but dimensional changes occur reducing precision
Solution Approach 1:
The patent changes the material parameters by using prealloyed powder with optimized carbon content (0.7-1.0%) and alloying element composition. This compositional change modifies the transformation characteristics during cooling, allowing the material to achieve high surface hardness through controlled martensitic transformation while minimizing volumetric expansion and dimensional distortion that typically occur with rapid cooling of conventional materials.
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 method enhances the dimensional precision and wear resistance of the slide, reducing the need for machining and improving fuel efficiency by maintaining a surface hardness of Hv0.3 550 or higher, while minimizing dimensional changes.
Implementation Method 1
The cooling of the sintered body slowly such that the temperature of the sintered body reaches the first temperature range may include performing a furnace cooling on the sintered body such that the temperature of the sintered body reaches a range of 830 to 870° C.
Implementation Method 2
The cooling of the sintered body rapidly when the first temperature range is reached may include cooling the sintered body such that the temperature of the sintered body reaches a range of 200 to 350° C. at a cooling rate of 2 to 3° C./s when the first temperature range is reached.
Implementation Method 3
The preparing of the sintered body by sintering the molded body may include preparing the sintered body by sintering the molded body at a sintering temperature of 1110 to 1160° C. for 25 to 35 minutes.
Data Source
AI summary
A method of manufacturing a slide of a variable oil pump for a vehicle includes preparing a molded body for a slide of a variable oil pump using prealloy powder including, in percent (%) by weight of the entire composition, 0.45 to 0.55% of carbon (C), 2.8 to 3.2% of chromium (Cr), 0.45 to 0.55% of molybdenum (Mo), 0.35 to 0.5% of manganese (Mn), 0.1 to 0.25% of sulfur (S), and the remainder of iron (Fe) and inevitable impurities. A sintered body is prepared by sintering the molded body. The sintered body is slowly cooled such that a temperature of the sintered body reaches a first temperature range and rapidly cooled when the first temperature range is reached.