Electric Park Lock Actuator with Rooster Comb Detent
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Solution Overview
Problem
Current electronic park lock actuators for vehicles are costly due to the need for larger motors with lower cogging torque and lower gear ratios, and they fail to effectively integrate with existing mechanical systems like the rooster comb, leading to reduced accuracy and increased complexity.
Innovation Solution
An electronic park lock actuator design utilizing a smaller motor with a higher gear ratio, incorporating a two-part actuator with an integrated pin and slot mechanism that limits back drivability and integrates with a spring-loaded rooster comb to achieve precise position holding and reduced mechanical and software complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a larger motor with lower gear ratio is used, then position control accuracy is improved, but device cost and complexity increase
Solution Approach 1:
Instead of using a large motor with low gear ratio to achieve position accuracy, the patent inverts the approach by using a small motor with high gear ratio and limiting the output rotation to precisely the amount needed to engage the park detent. This inversion allows achieving position control accuracy through mechanical constraint rather than motor size.
Solution Approach 2:
The actuator is divided into two functional parts: a small motor assembly for generating torque and a separate mechanism (rooster comb with detents) for position control. This segmentation allows each component to be optimized independently - the motor for compactness and the mechanical linkage for precision positioning.
2Ease of manufacture
If a smaller motor with higher gear ratio is used, then device cost is reduced, but position control accuracy deteriorates
Solution Approach 1:
A mechanical intermediary system (the rooster comb with multiple detents and the follower mechanism) is introduced between the small motor and the final output. This intermediary translates the limited motor rotation into precise position control by engaging with the transmission output shaft through the detent mechanism, thereby achieving accuracy without requiring a large motor.
3Adaptability or versatility
If back drivability is allowed, then operational flexibility is improved, but theft deterrence and position holding deteriorate
Solution Approach 1:
The patent extracts the back-drivability function from the system by designing a one-way mechanical linkage. The follower and detent mechanism allow motion in only one direction (from motor to transmission), preventing reverse driving while maintaining operational flexibility for the intended shifting operations. This extraction of the bidirectional capability resolves the contradiction between flexibility and security.
4Adaptability or versatility
If mechanical linkages are used for position control, then adaptability to existing systems is improved, but device complexity increases
Solution Approach 1:
The mechanical linkage design (rooster comb with multiple detents) is made universal by incorporating multiple engagement positions that can accommodate different transmission configurations. The same mechanism serves both as the position control element and as the interface with existing transmission systems, thereby reducing overall system complexity despite the mechanical nature of the solution.
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 efficient operation with a smaller motor, reduces design complexity, and enhances theft deterrence by limiting back drivability, while maintaining accurate position control and reducing motor peak current.
Implementation Method 1
A spring-loaded follower falls into these detents to identify the gear position
Implementation Method 2
an electric motor, a worm gear, the worm gear operable for being driven by the electric motor
Data Source
AI summary
An electronic parking pawl actuator which uses a smaller motor and higher gear ratio has the ability to configure a rooster comb to engage with various park detents, and reduces the mechanical and software design complexity. Furthermore, the electronic park actuator limits the amount of back drivable range (unable to perform an external park to neutral shift) for theft deterrence, and also allows operation (speed performance) and a lower motor peak current. The electronic parking pawl actuator includes an electric motor, a drive gear, the drive gear operable for being driven by the electric motor, and a drive mechanism, the drive mechanism is operable for being driven by the drive gear. The drive mechanism is engaged with an output shaft of a gear selector of a transmission, and the drive mechanism is rotatable relative to the drive gear, allowing the output shaft to be located in a desired position.