Axle Disconnect and Park Lock Assembly With Single Actuator
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Solution Overview
Problem
Existing vehicle systems with all-wheel drive and park lock functions are heavy and complex due to separate actuators for disconnect and park lock systems, which negatively impact fuel efficiency and vehicle weight.
Innovation Solution
A combined axle disconnect and park lock system using a single actuator that integrates a motor, shaft, gear, bearing, and ball screw mechanism to convert rotary motion into axial motion, allowing for three operational modes: two-wheel drive, all-wheel drive, and parked mode, utilizing a sleeve and shift assembly to engage or disengage splines for seamless transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate actuators are used for disconnect system and park lock system, then each function can be independently controlled, but the vehicle weight and system complexity increase
Solution Approach 1:
The patent combines the disconnect actuator and park lock actuator into a single integrated actuator unit. This single actuator performs both the disconnect function (engaging/disengaging the axle) and the park lock function (locking the parking pawl), thereby reducing overall system weight while maintaining independent control capability through electronic control signals
Solution Approach 2:
The integrated actuator is designed as a multi-functional device that can perform multiple operations: it can engage/disengage the disconnect clutch and simultaneously engage/disengage the parking lock mechanism. This universal design allows one component to replace what would traditionally require two separate components
2Reliability
If separate actuators are used for disconnect system and park lock system, then each function can be independently controlled, but the system complexity increases
Solution Approach 1:
The patent merges the disconnect actuator and park lock actuator into a single integrated unit with shared components including the motor, transmission mechanism, and control electronics. This consolidation reduces the number of separate systems that need to be designed, installed, and maintained, thereby reducing overall system complexity
3Force
If traditional separate systems are used, then adequate braking force is provided, but the time for park lock activation increases
Solution Approach 1:
The integrated actuator is designed to pre-position the parking pawl and synchronize its movement with the disconnect mechanism. When the park brake is activated, the system can rapidly engage the parking lock in conjunction with the disconnect operation, reducing the overall activation time while maintaining adequate braking force through the coordinated action of the park brake and parking lock
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 integrated system reduces weight, complexity, and cost while improving fuel efficiency by minimizing actuator count, ensuring smooth engagement, and reducing the time for park lock activation.
Implementation Method 1
A ball screw mechanism is connected to the motor and configured to convert rotary motion of the motor to axial motion along a shift rail
Data Source
AI summary
A combined axle disconnect and park lock system for a vehicle having a motive source and wheels. The system includes an output shaft and an intermediate gear permanently fixed for rotation with the output shaft. An output gear is mounted for selective relative rotation on the first output shaft. The system further includes a sleeve and a shift assembly configured to move the sleeve relative to the output shaft to place the system in a plurality of conditions. When the system is in a first condition of the plurality of conditions, the sleeve is moved such that the output gear can rotate relative to the first output shaft, and the drive wheels are free to rotate and are not coupled to the motive source. When the system is in a second condition of the plurality of conditions, the sleeve is moved such that the output gear cannot rotate relative to the first output shaft, and the drive wheels are free to rotate and are coupled to the motive source, when the system is in a third condition of the plurality of conditions, the sleeve is moved such that the drive wheels are not free to rotate.