Shift Range Control Apparatus Idle Running Current Limiting
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Solution Overview
Problem
Existing shift range control systems experience collision sounds during shift range switching due to play, such as gear backlash, between the motor shaft and output shaft.
Innovation Solution
A shift range control apparatus that includes an idle running determiner and a current limiter to determine if the motor is in an idle running state within the play range and limits the motor current to prevent collision sounds during shift range switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the motor shaft rotates quickly to overcome play between motor shaft and output shaft, then shift range switching response is improved, but collision sound occurs when play zone ends
Solution Approach 1:
The control device performs preliminary action by detecting the play range between motor shaft and output shaft before shift range switching, and pre-adjusts motor shaft rotation to eliminate play in the switching direction. This preliminary positioning prevents collision sound during subsequent switching by ensuring proper mechanical engagement before the actual shift operation begins
Solution Approach 2:
The control device uses feedback from play range detection to dynamically adjust motor shaft rotation control. By continuously monitoring the relationship between motor shaft and output shaft positions, the system provides feedback control that prevents excessive rotation into the play zone and eliminates collision sound while maintaining responsive shift range switching
2Object-generated harmful factors
If current limitation is applied during idle running, then collision sound is suppressed, but shift range switching response may be delayed
Solution Approach 1:
The control device dynamically adjusts current limitation based on real-time detection of idle running state and play range conditions. Current limitation is applied selectively during idle running when motor shaft rotates within play range, but automatically adjusted or released when shift range switching is detected or when motor shaft approaches the target position, thereby suppressing collision sound while minimizing delay in shift range switching response
Solution Approach 2:
The control device implements periodic monitoring of motor rotation state to detect idle running conditions and apply current limitation intermittently rather than continuously. This periodic control approach suppresses collision sound during idle phases while allowing full power delivery during active switching phases, reducing overall switching time penalty
Data Source
AI summary
A shift range control apparatus switching a shift range by controlling a drive of a motor, the shift range control apparatus includes: an idle running determiner that is configured to determine whether a rotation state of the motor is an idle running state in which the motor rotates within a range of play existing between a motor shaft being a rotation shaft of the motor and an output shaft to which a rotation of the motor is transmitted; and a current limiter that is configured to limit a current of the motor when it is determined that the rotation state of the motor is the idle running state.