Vehicle Door Motor Current Monitoring Counter
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Solution Overview
Problem
In vehicle opening and closing systems, thermistors can inadvertently cut off power to motors when foreign substances are trapped or operation frequency is high, leading to potential motor burnout without a suitable solution to prevent excess current damage.
Innovation Solution
A vehicle opening and closing apparatus that includes an electric motor, position detection, current measurement, and a counter system to monitor and manage motor current, stopping operations when excessive current is detected to prevent motor burnout without relying on thermistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thermistor is connected in the electric power distribution path to prevent motor burnout, then motor protection is improved, but the system may incorrectly cut off power when foreign substances are trapped or during high-frequency operation
Solution Approach 1:
The patent changes the protection mechanism from temperature-based (thermistor) to current-value-based counting. The control unit counts current values exceeding a threshold, and only stops operations when the count reaches a predetermined value, allowing temporary reverse operations to clear foreign substances without triggering protection incorrectly
Solution Approach 2:
The patent implements feedback by continuously monitoring motor current, counting exceedance events, and adjusting operation permission based on the accumulated count. This allows the system to distinguish between temporary overload conditions (foreign substances) and sustained abnormal conditions requiring protection
2Reliability
If a thermistor is used to limit current, then motor burnout is prevented, but the system cannot perform reverse operations to release trapped foreign substances
Solution Approach 1:
The patent makes the protection system dynamic by allowing temporary reverse operations when the foreign substance trapping is detected, even if current threshold is exceeded. The control unit permits reverse operations for a predetermined time period after detecting foreign substance trapping, enabling the system to adapt to different operational states
3Reliability
If current monitoring is implemented continuously, then motor protection is improved, but system complexity increases
Solution Approach 1:
The patent uses a simple counter that resets after reaching the predetermined value, rather than implementing complex temperature sensing and analysis systems. The counter acts as a disposable resource that is consumed and reset, providing protection without requiring complex continuous monitoring infrastructure
Data Source
AI summary
A vehicle opening and closing apparatus that opens and closes an opening and closing body provided on a vehicle includes: an electric motor that drives the opening and closing body; a position detection part that detects a position of the opening and closing body; a measurement part that measures a current value which flows in the electric motor when the opening and closing body arrives at a predetermined position; a counter that counts up a count value based on the current value; and a determination part that stops, for a predetermined period of time, the next and subsequent opening and closing operation of the opening and closing body when the count value exceeds a first threshold value.