Parking Lock State Check via Motor Shaft Axial Position Sensing
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Solution Overview
Problem
The existing parking lock actuator systems require a time-consuming referencing and plausibility check process to determine the state of the parking lock, especially when the sensed position is lost due to undervoltage, which can lead to jamming and increased operational time.
Innovation Solution
An inductive sensor system using a measuring coil integrated between the spindle rod and the printed circuit board, which changes inductance based on the axial position of the spindle rod, allowing for rapid determination of the parking pawl's latched or unlatched state without additional installation space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sensor is used to detect the position of the parking lock actuator, then the position can be monitored, but the referencing and plausibility check process becomes time-consuming when position information is lost
Solution Approach 1:
The patent replaces the mechanical sensor-based position detection with an inductive measurement system. The inductive sensor detects the axial position of the spindle rod through electromagnetic induction, eliminating the need for mechanical contacts and complex sensor assemblies. This substitution enables rapid position determination without the time-consuming referencing procedures required by mechanical sensors.
Solution Approach 2:
The patent changes the measurement parameter from mechanical position sensing to inductance measurement. By measuring the inductance of a coil that varies with the axial position of the spindle rod, the system可以快速 determine the parking lock state without physical contact or complex calibration procedures, thus reducing the time for referencing and plausibility checks.
2Measurement precision
If additional sensors are installed to improve position detection accuracy, then measurement precision improves, but device complexity and installation space increase
Solution Approach 1:
The patent makes the spindle rod serve multiple functions: it acts as both the actuating mechanism for the parking pawl and as the measurement target for the inductive sensor. The existing spindle rod structure is utilized for position measurement without requiring separate measurement components, thereby maintaining measurement precision while avoiding increased device complexity.
Solution Approach 2:
The patent merges the position measurement function with the existing actuator structure. The inductive coil is integrated into the housing, and the spindle rod serves as both the mechanical actuator and the magnetic target. This merging eliminates the need for additional separate sensors and reduces overall system complexity while maintaining measurement accuracy.
3Loss of information
If traditional sensor systems are used for position detection, then position information can be obtained, but the system requires additional installation space
Solution Approach 1:
The patent implements a nested structure where the inductive coil is positioned within the existing actuator housing, and the spindle rod passes through the coil's measurement field. The measurement system is nested within the existing mechanical structure, eliminating the need for additional external sensors and reducing the overall installation space while ensuring continuous position information availability.
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 solution significantly shortens the referencing and plausibility check process, enabling quicker recognition of the parking lock state and preventing jamming, while maintaining a compact design.
Implementation Method 1
The inductance of the measuring coil changes depending on the distance between the spindle rod and the printed circuit board
Implementation Method 2
an evaluation circuit which is arranged on a printed circuit board and comprises an oscillating circuit for evaluating the signal of the measuring coil when the spindle rod moves axially
Data Source
Figure 1
Figure 2a~2b
Figure 3a~3b
AI summary
The invention relates to a method for determining a state of a parking lock of a vehicle, according which method a parking pawl (5) is automatically interlockingly engaged in or disengaged from a parking lock wheel (8) by means of a parking lock actuator (13) driven by an electric motor (2). The invention also relates to a simplified plausibility check method, wherein an axial position of a motor shaft (3) of the electric motor (2) of the parking lock actuator (13) is detected to determine an additional state between engagement and disengagement of the parking pawl (5).