Shift-By-Wire Gear Actuator With Threaded Carriage Positioning
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Solution Overview
Problem
Conventional shift-by-wire mechanisms in vehicles lack an efficient and compact actuator system that can accurately and reliably adjust transmission gear settings using minimal power while maintaining mechanical advantage and preventing contamination.
Innovation Solution
A shift actuator system featuring a drive assembly with a threaded actuator, a carriage that translates linearly along the actuator, and an actuator arm that translates linear motion into rotational motion of the transmission selector, utilizing a positioning magnet and sensor to ensure precise gear positioning, with a gear-reduction mechanism and mechanical advantages to reduce motor size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a conventional actuator system is used for shift-by-wire mechanisms, then the transmission can be adjusted between multiple gears, but the system lacks mechanical advantage requiring a larger motor and consumes more power
Solution Approach 1:
The actuator system employs a dynamic mechanism where the carriage translates along a threaded actuator, and the actuator arm converts this linear motion into rotational motion of the transmission selector. This dynamic motion conversion provides mechanical advantage, allowing a smaller, more power-efficient motor to operate the transmission across multiple gear positions.
2Volume of moving object
If a compact actuator design is implemented, then the system size is reduced, but the risk of contamination increases
Solution Approach 1:
The actuator components are nested within a sealed housing structure. The carriage moves along the threaded actuator inside the housing, and the actuator arm rotates within the same enclosed space. This nested, sealed design maintains a compact volume while protecting internal components from contamination by keeping them enclosed throughout their motion paths.
3Measurement precision
If precise gear positioning is achieved through positioning sensors and magnets, then gear selection accuracy is improved, but the device complexity increases
Solution Approach 1:
The positioning system replaces complex mechanical measurement devices with a simpler magnetic field-based sensor assembly. A magnet is positioned on the actuator arm, and a magnetic sensor detects its position to determine the transmission selector's gear position. This substitution of mechanical sensing with magnetic sensing achieves precise gear positioning while reducing overall device complexity.
4Force
If a threaded actuator mechanism is used to convert rotational motion to linear motion, then mechanical advantage is gained, but the device complexity increases
Solution Approach 1:
The threaded actuator serves as an intermediary mechanism between the motor's rotational output and the carriage's linear motion. The threads convert rotational motion into linear displacement, providing mechanical advantage that allows a small motor to generate sufficient force for gear selection. This intermediary mechanism is integrated into a compact actuator assembly that minimizes overall complexity while maintaining the force multiplication benefit.
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 system provides a compact, efficient, and reliable gear selection mechanism that maintains output torque, reduces contamination risk, and allows for precise gear adjustments with minimal power consumption, suitable for shift-by-wire applications.
Implementation Method 1
A threaded actuator is rotationally operated by the drive assembly. A carriage linearly operates along the threaded actuator
Implementation Method 2
An actuator arm extends between the carriage and the transmission selector to translate linear operation of the carriage to rotational operation of the transmission selector
Implementation Method 3
A position sensor is in communication with the selector interface, the actuator arm and a motor of the drive assembly to locate the carriage and the actuator arm at the plurality of actuator positions
Data Source
AI summary
A shift actuator for a transmission includes a drive assembly coupled with a selector interface. A transmission selector operates between a plurality of transmission settings. A threaded actuator is rotationally operated by the drive assembly. A carriage linearly operates along the threaded actuator to define a plurality of actuator positions that correspond to the transmission settings. An actuator arm extends between the carriage and the transmission selector to translate linear operation of the carriage to rotational operation of the transmission selector.