Actuator Assembly for Load-Free Shifting in Drivelines
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Solution Overview
Problem
Existing driveline actuator systems for motor vehicles lack efficient mechanisms for short, load-free overlap shifting, which is essential for achieving high performance and driving comfort in multi-stage automated transmissions.
Innovation Solution
An actuator assembly comprising a housing, an actuator drive, a switching rod, and two switching elements, where the switching rod can be moved by the actuator drive into at least three positions, with spring elements pressing the switching elements against shaft stops, allowing for simultaneous actuation of multiple switching units with a simple and cost-effective design, including the use of form-locking clutches that require low shifting force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional synchronizers or clutches are used for shifting switching units, then reliable gear changes can be achieved, but high shifting force and complex structure are required
Solution Approach 1:
The shifting process is divided into two independent stages: first disengaging the old gear, then engaging the new gear. This segmentation allows each switching element to operate independently with reduced force requirements, eliminating the need for high-force synchronizers while maintaining reliable gear changes.
Solution Approach 2:
The actuator drive first moves the switching rod to disengage the current gear before engaging the next gear. This preliminary disengagement action prepares the drivetrain for the subsequent gear engagement, enabling smooth transitions without requiring high simultaneous shifting forces.
2Speed
If multiple switching units are actuated simultaneously, then shifting speed can be improved, but load-free overlap shifting becomes difficult to achieve
Solution Approach 1:
The actuator drive dynamically controls the switching rod to achieve overlap shifting where the second switching element begins moving before the first switching element completes its stroke. This dynamic sequencing enables fast, load-free shifts without requiring complex multi-actuator systems.
Solution Approach 2:
A single actuator drive performs multiple functions: it actuates both switching elements sequentially, controls the timing of gear changes, and enables overlap shifting. This multi-functionality achieves high-speed shifting without increasing device complexity.
3Device complexity
If a single actuator drive is used to actuate multiple switching elements, then device complexity is reduced, but the ability to achieve precise positioning of multiple switching units is compromised
Solution Approach 1:
The single actuator drive is equipped with multiple independent switching elements (first switching element 6 and second switching element 7) that can be positioned independently on the switching rod. This segmentation allows precise positioning of multiple switching units while using a simple single-actuator system.
Solution Approach 2:
The switching rod acts as an intermediary component that transmits the actuator drive's motion to multiple switching elements at different positions. By adjusting the axial positions of switching elements on the rod, precise positioning is achieved without requiring multiple actuators.
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
Enables efficient shifting of multiple switching units in the driveline with reduced load shifting, allowing for serial shifting during gear or mode changes, thereby enhancing driving comfort and performance while minimizing the need for load shifting and using low-force shifting units compared to conventional synchronizers or clutches.
Implementation Method 1
a spring element (17) which presses the first switching element (6) against a first shaft stop (18) and the second switching element (7) against a second shaft stop (19) in opposite axial directions
Implementation Method 2
a switching rod (4) which is arranged in the housing and can be moved by the actuator drive (3) into at least three positions
Data Source
AI summary
An actuator assembly for actuating two switching units in the driveline of a motor vehicle comprises a housing; an actuator drive; a switching rod arranged in the housing and axially movable by the actuator drive in three positions; a first switching element and a second switching element axially movably arranged on the switching rod; a spring element which biases the first switching element against a first shaft stop and the second switching element against a second shaft stop; a first housing stop against which the first switching element can be axially supported; and a second housing stop against which the second switching element can be axially supported. A transmission assembly can include such an actuator assembly.