Parking Lock Actuator With Spindle Drive for High Release Torque
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Solution Overview
Problem
Conventional parking lock actuators face challenges in providing high release forces without excessive actuation power and maintaining a compact design, while supporting high loads and preventing unintentional vehicle movement, especially on inclined surfaces.
Innovation Solution
A parking lock actuator utilizing a spindle drive with a pivotally fixed lever and a spring element that aids in torque transmission, allowing for high torque generation during release and efficient energy storage for locking, combined with a self-locking spindle drive and form-fitting connections for robustness and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a conventional gearing system (spur gears or worm gears) is used to provide high release forces, then the actuator can generate sufficient torque, but the system suffers from deformation, wear, creeping phenomena, and excessive noise over time
Solution Approach 1:
The patent replaces the conventional gearing system (spur gears or worm gears) with a spindle drive mechanism. The spindle drive consists of a spindle with threaded engagement and a nut that converts rotational motion into linear motion, which is then transformed into rotational motion of the output element through a lever. This substitution eliminates the deformation, wear, and creeping phenomena associated with gear systems while maintaining the ability to generate high release forces.
2Force
If the actuator is designed to provide high torque in the release direction, then it can handle high external loads, but the device size increases due to over-sizing of the gearing kinematics
Solution Approach 1:
The patent changes the mechanical parameters of the transmission system by using a spindle drive with optimized thread geometry and lever arm dimensions. This allows the actuator to generate the required high torque in the release direction without over-sizing the entire gearing system. The spindle drive efficiently converts motor torque into linear force on the nut, which is then amplified by the lever mechanism to produce the necessary output torque.
3Reliability
If a self-locking mechanism is implemented to prevent unintentional vehicle movement, then safety is improved, but the actuation power required increases
Solution Approach 1:
The patent segments the locking function into two independent mechanisms: the spindle drive provides self-locking through its threaded geometry, preventing unintentional movement without requiring continuous power, while the spring element assists only during the release operation to overcome high external loads. This segmentation allows the actuator to achieve safety without excessive actuation power, as the spring supplementarily aids only when needed during unlocking.
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
The solution enables a robust, compact, and high-performance parking lock actuator that efficiently supports high loads and maintains accurate positioning, reducing noise and deformation, with symmetrical load distribution enhancing its operational efficiency and longevity.
Implementation Method 1
a spring element (52) that acts on the lever (30), supporting the nut (24) in providing part of the torque required for rotating the output element (18) in the release direction (Ro)
Implementation Method 2
a spindle drive (16) comprising a spindle (22) and a nut (24) that is connected to the spindle (22) in a manner so that the nut (24) is linearly translated, when the spindle (22) is rotated
Implementation Method 3
The lever (30) is pivotally fixed at a pivot axis (32) so that the lever (30) is pivoted when the nut (24) is linearly translated
Data Source
Figure 1
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AI summary
A parking lock actuator (10) has an output element (18) which is rotatably mounted so as to be rotatable between a locking position and a release position, a spindle drive (16) that includes an electric motor (20), a spindle (22) rotatably connected with the electric motor (20) and a nut (24) non-rotatably accommodated on the spindle (22), and a lever (30) for converting a translational movement of the nut (24) into a rotation of the output element (18). The nut (24) is connected to the lever (30) and the lever (30) is connected to the output element (18) in a torque-transmitting manner.