Gas Flow Control Valve Assembly with Oil-Lubricated Press-Fitting
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Solution Overview
Problem
Existing double-valve-type exhaust gas recirculating valves face challenges with exhaust gas leakage due to inaccurate component dimensions, leading to increased manufacturing costs and variability, especially when handling large flow rates in diesel engines.
Innovation Solution
An assembly method that press-fits valves and valve seats with oil lubrication, measuring and adjusting distances to minimize leakage, allowing for high accuracy in leakage adjustment even with components manufactured by sintering machining, which typically have low dimensional accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If form turning is used to manufacture valves and valve seats, then manufacturing precision is improved, but productivity deteriorates and manufacturing cost increases
Solution Approach 1:
The invention changes the manufacturing method from form turning to sintering machining, altering the production process parameters to achieve a balance between dimensional accuracy and manufacturing efficiency. Sintering allows for faster production while maintaining sufficient precision for the application.
Solution Approach 2:
The invention accepts that sintered components have slightly lower dimensional accuracy compared to form-turned components, but compensates through the assembly method that adjusts and equalizes distances, making the slightly less precise components sufficiently accurate for the final product.
2Productivity
If sintering machining is used to manufacture valves and valve seats, then productivity is improved and manufacturing cost is reduced, but manufacturing precision deteriorates
Solution Approach 1:
The invention performs preliminary measurement and adjustment of component distances during assembly. By measuring the distance from each valve to its corresponding valve seat and adjusting the shorter distance to match the longer one, the method compensates for the lower dimensional accuracy of sintered components before final assembly.
Solution Approach 2:
The invention implements a feedback mechanism where the measured distances between valves and valve seats are used to adjust and equalize the positions. This closed-loop approach ensures that even components with varying dimensions from sintering machining achieve uniform and accurate final positions.
3Reliability
If high dimensional accuracy is required for valves and valve seats, then valve seat leakage is reduced, but manufacturing cost increases
Solution Approach 1:
The invention performs preliminary measurement and adjustment of component distances during assembly. By measuring the distance from each valve to its corresponding valve seat and adjusting the shorter distance to match the longer one, the method compensates for the lower dimensional accuracy of sintered components before final assembly.
Solution Approach 2:
The invention changes the manufacturing method from form turning to sintering machining, altering the production process parameters to achieve a balance between dimensional accuracy and manufacturing efficiency. Sintering allows for faster production while maintaining sufficient precision for the application.
4Ease of manufacture
If components with varied positions are assembled, then ease of manufacture is improved, but manufacturing precision deteriorates due to distance variations
Solution Approach 1:
The invention implements a feedback mechanism where the measured distances between valves and valve seats are used to adjust and equalize the positions. This closed-loop approach ensures that even components with varying dimensions from sintering machining achieve uniform and accurate final positions.
Solution Approach 2:
The invention performs preliminary measurement and adjustment of component distances during assembly. By measuring the distance from each valve to its corresponding valve seat and adjusting the shorter distance to match the longer one, the method compensates for the lower dimensional accuracy of sintered components before final assembly.
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 method effectively reduces valve seat leakage to zero at ordinary temperatures, improves the reliability of gas-mass-flow control valves, and accommodates variations in component sizes, enhancing the assembly process's precision and cost-effectiveness.
Implementation Method 1
placing oil between an outer surface of a first large-diameter portion of the above-mentioned valve shaft and an inner surface of the above-mentioned first valve; press-fitting the above-mentioned first valve to the above-mentioned first large-diameter portion of the above-mentioned valve shaft
Data Source
AI summary
An assembly method includes a step of press-fitting a second valve 27 to a valve shaft 29 to which a first valve 25 is press-fitted and secured while measuring and adjusting a distance L2 so that it becomes equal to a distance L1. Thus, the first valve 25 and second valve 27 are press-fitted to the valve shaft 29 and those components are swaged together so that the first and second valves are secured to the valve shaft, and oil is placed in a press-fitted portion. When components, such as the first valve 25, are sintered parts, oil contained in the sintered parts themselves is used for increasing a joining force that occurs in the press-fitted portion.