Gearbox Actuator Decoupling for Stable Shaft Positioning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing gearbox actuators for motor vehicles face challenges in accurately positioning the gearbox shaft due to manufacturing tolerances, cogging torque, and restricted movement, especially during electric power failures and transitions between gear positions.
Innovation Solution
A reversible gearbox actuator with an electric motor and a transmission mechanism that couples and decouples from the gearbox shaft to allow free rotation, using a driving wheel mechanism with biasing means like torsion springs to ensure accurate positioning without permanent engagement, and an electronic controller to reverse the motor's rotation direction for uncoupling and gear shifting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the transmission mechanism remains permanently engaged with the shaft member, then the actuator can maintain precise control over the shaft position, but the shaft cannot rotate freely to reach stable gear positions due to manufacturing tolerances and cogging torque
Solution Approach 1:
The transmission mechanism transitions from a permanently engaged state to a decoupled state, allowing the shaft member to rotate freely. The biasing means (torsion spring) dynamically adjusts the engagement status based on the shaft's position relative to stable gear positions, enabling free rotation when needed while maintaining control when required.
Solution Approach 2:
The actuator periodically engages and disengages the transmission mechanism with the shaft member during operation. The controller reverses the motor's rotation direction at specific intervals to decouple the transmission mechanism, allowing the shaft to settle into stable positions, then re-engages it for precise positioning control.
2Speed
If the actuator continuously drives the shaft member to gear positions, then positioning speed is improved, but the shaft member cannot self-correct its position due to tolerances and cogging effects
Solution Approach 1:
The actuator uses periodic engagement and disengagement cycles. During engagement phases, the motor drives the shaft quickly to near-target positions. During disengagement phases, the shaft is allowed to freely rotate and self-correct to precise stable positions under the influence of the contoured surface and biasing means, combining speed with precision.
Solution Approach 2:
The shaft member is designed to self-correct its position when the transmission mechanism is decoupled. The contoured surface with valleys and peaks, combined with the biasing means, enables the shaft to automatically settle into accurate stable gear positions without continuous active control, leveraging passive mechanical elements for precision.
3Reliability
If the transmission mechanism is always engaged, then control over the shaft member is maintained, but the system cannot accommodate power failures or unexpected stoppages without leaving the shaft in unstable positions
Solution Approach 1:
The biasing means (torsion spring) is pre-configured to provide a restoring force that guides the shaft member toward stable gear positions. In case of power failure or unexpected stoppage, this pre-loaded mechanical element ensures the shaft will naturally settle into a stable position without requiring active control, providing fail-safe operation.
Solution Approach 2:
The system uses passive mechanical elements (contoured surface, biasing means) to enable the shaft member to self-correct and stabilize at gear positions without requiring continuous active control or power supply. This self-service capability ensures reliable operation even during power failures or unexpected stoppages.
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 actuator achieves precise and stable gear positioning by avoiding restrictions on the gearbox shaft's movement, ensuring accurate alignment with the contoured surface, even during power failures and transitions, enhancing the gearbox's operational accuracy and flexibility.
Implementation Method 1
biasing means like torsion springs to ensure accurate positioning without permanent engagement
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3
AI summary
The invention refers to a gearbox actuator comprising: an electric motor, a shaft member rotatable about a gearbox axis (X), and a transmission mechanism coupled with the electric motor and couplable with the shaft member for transmitting a rotation movement from the electric motor to the shaft member to bring the shaft member to selected angular positions for shifting gears. The actuator is configured such that the transmission mechanism can move in a direction in which it is coupled with the gear shaft member while bringing the gear shaft member to a stable gearbox position. Preferably, the actuator is configured such that the transmission mechanism reverses movement direction and uncouples from the shaft member to create a separation gap between the shaft member and the transmission mechanism, that allows the shaft member to rotate freely to reach a stable gearbox position. The invention allows free movement of a gearbox shaft to accurately reach stable gear positions.