Automated Manual Transmission Planetary Gear Shift Mechanism
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Solution Overview
Problem
Automated manual transmissions experience shift quality deterioration due to torque reduction during shifting, leading to vehicles being pulled back, and existing solutions increase weight and cost by using multiple planetary gear devices.
Innovation Solution
The implementation of a common use planetary gear device with three rotation elements and a dedicated planetary gear device, along with a shift gear mechanism using external gear mates and a friction member to brake the ring gear, allows for efficient power transmission and reduced shift time, eliminating the need for synchronizers and minimizing the number of planetary gear devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a synchromesh type shift mechanism is used in automated manual transmission, then the shifting can be performed automatically, but torque is reduced during shifting causing shift quality deterioration and vehicle pullback
Solution Approach 1:
The planetary gear device is engaged before the shift operation to pre-establish a power transmission path. During shifting, the friction member brakes the ring gear to maintain torque transmission through the planetary gear device, preventing torque reduction and vehicle pullback while enabling automatic shifting.
Solution Approach 2:
The planetary gear device acts as an intermediary power transmission mechanism between the input and output. By engaging the planetary gear device and using the friction member to brake the ring gear, it mediates the power flow during shifting, maintaining torque transmission and improving shift quality.
2Reliability
If multiple planetary gear devices are installed to transmit engine power during driving and shifting, then shift quality is improved, but the transmission length and weight increase
Solution Approach 1:
The planetary gear device is designed to serve multiple functions: it transmits engine power during driving, maintains torque during shifting, and enables both driving and shifting operations. This multi-functionality eliminates the need for separate planetary gear devices for different operations, reducing transmission weight and length.
Solution Approach 2:
The planetary gear device combines the functions of power transmission during driving and torque maintenance during shifting into a single mechanism. By merging these functions and using the friction member to control the ring gear, the design reduces the number of components needed, thereby reducing overall transmission weight and length.
3Adaptability or versatility
If synchronizers are used for all shift operations, then each shift stage can be implemented, but the shift operation becomes slow
Solution Approach 1:
The friction member replaces the traditional synchronizer mechanism for controlling shift operations. By using friction-based braking on the ring gear instead of mechanical synchronizers, the system achieves faster shift response while maintaining the ability to implement different shift stages through the planetary gear device.
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
This configuration enhances shift quality by reducing shift time and preventing torque reduction, while minimizing the transmission's length and weight, thus improving fuel efficiency and reducing costs.
Implementation Method 1
a friction member disposed to brake the ring gear of the planetary gear device to transmit the rotation power transmitted to the input at the time of the braking to the output through the external gear mates
Data Source
AI summary
An automated manual transmission includes an input, an output disposed in parallel with the input, a common use planetary gear device disposed on the input or the output, a shift gear device in which a plurality of external gear mates having different shift ratios are disposed on the input and the output, and a friction member disposed to transmit the rotation power transmitted to the input at the time of the braking to the output through the external gear mates.