Switchable Linear Actuator for Seamless AMT Gear Shifts
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Solution Overview
Problem
Automated manual transmissions experience undesirable shift feel and torque interruption during gear shifts, leading to uncomfortable driving experiences due to the disconnection and reconnection of engine torque with the drivetrain.
Innovation Solution
A switchable linear actuator device utilizing magnetic sources to create net translational forces, controlling locking members between coupling positions, enabling sequenced shifts in a radial coupling assembly to manage torque flow smoothly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If automated manual transmissions disconnect and reconnect engine torque during gear shifts, then gear ratio changes are achieved, but shift feel becomes undesirable and torque interruption occurs
Solution Approach 1:
The system pre-positions locking members in advance to engage with load-bearing shoulders before torque interruption occurs. The multi-stage clutch assembly is prepared with locking members that can be sequentially engaged to maintain continuous torque flow, preventing the harsh disconnection-reconnection cycle that causes poor shift feel.
Solution Approach 2:
The patent introduces intermediate locking members and load-bearing shoulders that act as mediators between the input and output shafts. These intermediaries allow torque to be transferred through alternative paths during gear shifts, preventing direct torque interruption and maintaining smooth power delivery throughout the shifting process.
2Reliability
If traditional one-way clutches use spring loaded rollers or asymmetrically shaped wedges, then locking in one direction and free rotation in the other direction is achieved, but parasitic losses occur and complexity increases
Solution Approach 1:
The patent replaces traditional spring-loaded rollers and asymmetrically shaped wedges with a novel locking member design that uses load-bearing shoulders and direct mechanical engagement. This substitution eliminates the need for springs and complex wedge geometries, reducing parasitic losses while maintaining reliable locking in the desired direction.
Solution Approach 2:
The invention changes the geometric parameters of the locking mechanism by using radially extending locking members that engage with load-bearing shoulders positioned at specific radial distances. This parameter change allows the locking members to engage more efficiently, reducing energy losses associated with traditional roller and wedge designs.
3Adaptability or versatility
If controllable one-way clutches add a second set of locking members and slide plate, then multiple functions are achieved, but device complexity increases
Solution Approach 1:
The patent merges the functions of multiple locking members and control elements into a unified multi-stage clutch assembly. The locking members are radially positioned and can be selectively engaged through a single control mechanism, combining what would traditionally require separate assemblies into one integrated structure, thereby reducing overall complexity while maintaining multiple operating modes.
Solution Approach 2:
The radially extending locking members are designed to perform multiple functions: they can engage with different load-bearing shoulders at different radial positions to provide various clutch stages, and they can operate in both locking and overrunning modes. This multi-functionality eliminates the need for separate locking members and slide plates, reducing structural complexity.
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 provides a seamless torque transition during gear shifts, reducing shift shock and improving driving comfort by ensuring continuous power delivery without abrupt interruptions.
Implementation Method 1
A stator structure includes a first electromagnetic source configured to create a first electronically-switched magnetic field and a second electromagnetic source configured to create a second electronically-switched magnetic field
Implementation Method 2
A translator structure includes a first cam having a contour surface, a second cam having a contour surface and a magnetically-latching, permanent magnetic source magnetically coupled to the stator structure across a radial air gap
Data Source
AI summary
A switchable linear actuator device and an overrunning, non-friction, radial coupling and control assembly using the device are provided. The device has magnetic sources which produce corresponding magnetic fields to create net translational forces. The device includes a first and locking members and a stator structure including a first and second electromagnetic sources configured to create first and second electronically-switched magnetic fields, respectively. A translator structure includes first and second cams having contour surfaces and a magnetically-latching, permanent magnetic source magnetically coupled to the stator structure across a radial air gap. The translator structure translates along an axis between first and second axial positions and between second and third axial positions upon experiencing first and second net translational forces, respectively, to cause the first and second locking members to ride on the contour surfaces of the first and second cams, respectively, and perform a sequenced shift.