Valve Control Apparatus Dynamic Soft Landing
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Solution Overview
Problem
In EGR valves where the motor shaft and valve shaft are integrally formed, shock occurs during valve seating, and high drive duty ratios can lead to motor failure and bearing fatigue due to excessive load.
Innovation Solution
A valve control apparatus that includes a drive control unit for feedback control of the valve's open position and a fully closed state determining unit, which sets a soft landing start target position and gradually decreases it to manage the drive duty ratio, reducing shock and preventing motor and bearing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the valve shaft is rapidly retracted to close the valve quickly, then the response speed is improved, but shock occurs when the valve element seats onto the valve seat causing potential damage
Solution Approach 1:
The patent applies dynamics by making the valve closing speed variable rather than constant. The drive control unit adjusts the motor driving force dynamically during the closing process: applying higher force when the valve element is away from the seat to achieve rapid closing, and reducing force as the valve element approaches the seat to enable gentle seating. This dynamic speed adjustment resolves the contradiction between fast response and shock prevention.
2Reliability
If the drive duty ratio is increased to maintain the valve in fully closed state for long periods, then the sealing reliability is improved, but motor heat generation increases leading to potential motor failure
Solution Approach 1:
The patent applies partial action by using minimal necessary driving force to maintain the valve in fully closed state. Once the valve element is seated, the drive control unit reduces the motor driving force to the minimum level required to maintain sealing, rather than continuously applying high drive duty ratio. This partial action approach maintains sealing reliability while significantly reducing motor heat generation and preventing motor failure.
3Reliability
If large retracting force is applied to the rotor assembly to ensure complete valve closure, then the sealing performance is improved, but the waved washer supporting the bearing becomes fatigued and damaged
Solution Approach 1:
The patent applies dynamics by adjusting the retracting force on the rotor assembly according to the valve closing stage. During the main closing phase, sufficient force is applied to ensure complete closure and sealing performance. However, as the valve element approaches and makes contact with the seat, the drive control unit reduces the retracting force to minimize the load on the waved washer and bearing support structure. This dynamic force adjustment maintains sealing performance while preventing waved washer fatigue and damage.
Data Source
AI summary
A valve control apparatus sets a certain soft landing start target position to a drive control unit for carrying out driving of a DC motor 2 as a target open position in response to a fully close command, and sets the target open position which the valve control apparatus acquires by gradually decreasing the soft landing start target position to the above-mentioned drive control unit at a time when the difference between an actual open position and the soft landing start target position becomes equal to a first threshold.