Parking Lock Actuator With Pivoting Armature for Power-Fail Engagement
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Solution Overview
Problem
Existing motor vehicle automatic transmission parking lock actuators face challenges in ensuring safe and efficient engagement of the P stage, particularly in situations where a separate voltage source is unavailable, leading to potential safety hazards and unintended disengagement of the parking lock.
Innovation Solution
An actuator design featuring a spring element with an electromagnetic holding device and a tiltable magnet armature, which maintains the spring element in a pre-tensioned state using an electromagnet, ensuring the P stage is engaged securely without the need for additional voltage sources, and allows for preload of the spring element before leaving the P stage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an independent voltage source is used to trigger the emergency mechanism, then the emergency function can be activated, but the system becomes unreliable when the voltage source is unavailable
Solution Approach 1:
The actuator uses its own motor to pre-tension the spring element during normal operation, making the system self-preparing for emergency situations without requiring external voltage sources. The motor-driven spool valve moves the spool to the non-parking position, which tensions the spring element in preparation for emergency P-stage engagement.
Solution Approach 2:
The spring element is pre-tensioned during normal actuator operation before any emergency situation occurs. This preliminary action ensures that when power failure or malfunction happens, the spring element is already in the correct state to immediately engage the P-stage without requiring additional voltage sources or preparation steps.
2Reliability
If the P stage is left to pre-tension the spring element, then the spring is ready for emergency engagement, but the P stage remains engaged creating an unsafe vehicle situation
Solution Approach 1:
The actuator is divided into two independent actuating elements: the first actuating element controls the spool valve and transmission shifting, while the second actuating element controls the spring element tensioning. This segmentation allows the spring to be pre-tensioned independently without changing the transmission position, eliminating the hazard of unintended disengagement.
Solution Approach 2:
A detent mechanism acts as an intermediary to mechanically hold the spool in the non-parking position while allowing the spring element to be pre-tensioned. The detent provides a mechanical locking function that decouples the spring tensioning state from the transmission position state, enabling safe pre-preparation for emergency engagement.
3Force
If a flat contact surface is used between magnetic armature and electromagnet, then magnetic holding force is maximized, but manufacturing precision requirements increase
Solution Approach 1:
The magnetic armature is mounted on a pivoting part that allows it to tilt or pivot, making the contact surface dynamically adjustable. This dynamic capability compensates for manufacturing tolerances and misalignments, ensuring optimal flat contact with the electromagnet during operation without requiring extremely precise manufacturing.
Solution Approach 2:
The mounting configuration allows the magnetic armature to change its orientation parameters (tilt angle, pivot position) to achieve optimal contact. By allowing parameter changes in the armature position, the system can compensate for manufacturing variations and maintain maximum magnetic holding force without requiring ultra-precise flat surfaces.
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
Guarantees reliable and efficient engagement of the parking lock in all situations, including power failures, by maintaining the spring element's tension and preventing unintended disengagement, thus enhancing safety and operational efficiency.
Implementation Method 1
an electromagnetic holding device with an electromagnet (50) which magnetically interacts with a magnetic armature (52) having ferromagnetic material components to hold the spring element (5), which is tensioned under a restoring force, in its position
Implementation Method 2
magnetically interacts with a magnetic armature (52) having ferromagnetic material components
Data Source
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AI summary
The invention relates to an actuator having a drive (2) driving a drive shaft (1), a first actuating element (3) operatively connected to the drive shaft (1) for actuating a switching device, a spring element (5), which is supported on the one side on a housing component (16) of the actuator and on the other side on a second actuating element (17) designed to load the spring element (5), and having an electromagnetic retaining device (32) with an electromagnet (50), which interacts magnetically with a magnetic armature (52) comprising a ferromagnetic material component to retain the spring element (5) which is under loading, building up a spring return force. According to the invention, the magnetic armature (52) is mounted tiltably and/or pivotably on a pivot component (55) of the retaining device (32).