Parking Lock Device Terminal Voltage Limiting
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Solution Overview
Problem
Conventional parking lock devices for motor vehicles face issues with unintentional release or loosening due to failures in the vehicle electrical system or control device, particularly when the spring device is discharged during tensioning, leading to kinetic energy causing the locking element to move out of the blocking position.
Innovation Solution
A parking lock device incorporating an electronic limiting device that automatically limits terminal voltage between the electric motor's terminals, combined with a spring device and holding mechanism, ensures the locking element remains in the blocking position even during electrical failures, using a transistor circuit to short-circuit the motor and brake it, thereby preventing unintended release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the spring device is pre-tensioned by the actuator to enable automatic locking in case of power failure, then the reliability of the locking function is improved, but the kinetic energy of the electric motor during spring tensioning can cause unintentional release if the electrical system fails
Solution Approach 1:
The patent converts the harmful kinetic energy of the electric motor during spring tensioning into a beneficial braking effect by allowing the motor to generate reverse voltage (back EMF) when the spring releases. This reverse voltage naturally opposes the motor's rotation, creating an automatic braking effect that prevents the motor from overspeeding and causing unintentional release. The harmful kinetic energy is thus transformed into a useful energy dissipation mechanism through electromagnetic induction.
2Reliability
If the holding device is automatically released in case of power failure to free the spring device, then the locking element can be moved into the locked position, but without control the electric motor can reach high speeds causing delayed stop and disengagement
Solution Approach 1:
The patent implements a feedback mechanism where the electric motor's own operation during spring tensioning generates reverse voltage (back EMF) that automatically opposes and limits its speed. When the spring releases and drives the motor, the motor's rotation induces a voltage that opposes the driving force, creating a self-regulating feedback loop. This natural feedback prevents the motor from reaching dangerous speeds without requiring external control systems.
3Ease of operation
If the electric motor is used to tension the spring device, then the locking element can be positioned, but during electrical system failure the motor's kinetic energy cannot be controlled
Solution Approach 1:
The patent makes the electric motor self-regulating during uncontrolled operation by utilizing its own electromagnetic properties. When the spring releases and drives the motor during electrical failure, the motor automatically generates reverse voltage that opposes its rotation, creating an inherent speed limitation. The system serves itself by using the motor's own operational characteristics to prevent the harmful effects of uncontrolled operation, eliminating the need for external control systems during failures.
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 enhances operational reliability by actively braking the electric motor and reducing kinetic energy, ensuring the parking lock remains engaged even in the event of electrical system failures, thus preventing unintentional release and improving safety and cost-effectiveness.
Implementation Method 1
The electric motor has a first terminal and a second terminal, with the control device designed to control the electric motor and electrically coupled to the first and second terminals
Implementation Method 2
using a transistor circuit to short-circuit the motor and brake it, thereby preventing unintended release
Data Source
Figure 1
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AI summary
The invention relates to a parking lock device (1) for a motor vehicle (2), comprising a locking device (12), an actuator device (6), a cable drive (8), and a control device (11). The locking device (12) has a locking element (3), a guide device (36), a spring device (13), and a holding device (14), wherein the locking element (3) is configured to lock a rotatably mounted drive element (4) of a drive system (5) of the motor vehicle (2) in a locked position (S) and to release the drive element (4) in a release position (F). The guide device (36) is configured to guide the locking element (3), wherein the spring device (13) is configured to move the locking element (3) relative to the guide device (36) in one direction. The holding device (14) is configured to hold the locking element (3). The actuator device (6) has an electric motor (7) for moving the guide device (36).The cable drive (8) is mechanically coupled to the locking element (3). The electric motor (7) has a first terminal (9) and a second terminal (10), wherein the control device (11) is designed for controlling the electric motor (7) and is electrically coupled to the first terminal (9) and the second terminal (10). The parking lock device (1) has an electronic limiting device (15) for automatically limiting a terminal voltage between the first terminal (9) and the second terminal (10) of the electric motor (7). Furthermore, the invention relates to a motor vehicle (2) with a parking lock device (1) according to the invention.