Power Shift Transmission Branching Unit Torque Path Design
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Solution Overview
Problem
Existing powershift transmissions face inefficiencies in torque transfer through torque converters, which affect transmission efficiency and make stepless design less effective.
Innovation Solution
A powershift transmission design with a branching unit on the input shaft dividing torque between two paths, where a switching group with multiple stages is used in the mechanical path and a torque converter in the non-mechanical path, allowing torque to be transmitted via both paths, with a clutch connecting two output shaft units for efficient power distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a torque converter is used in the non-mechanical power path for stepless torque transmission, then adaptability and smooth operation are improved, but transmission efficiency deteriorates due to relatively inefficient torque transfer
Solution Approach 1:
The output shaft is divided into two separate units (first output shaft unit and second output shaft unit) that can be selectively connected via a clutch. This segmentation allows the system to choose between mechanical power transmission (higher efficiency) and non-mechanical torque converter transmission (better adaptability) for different operating conditions, resolving the contradiction by enabling context-dependent optimization.
Solution Approach 2:
The clutch connecting the two output shaft units is designed to be dynamically switchable, allowing the system to adapt in real-time between mechanical and non-mechanical power paths. This dynamic switching capability enables the system to maintain high efficiency when mechanical transmission suffices while utilizing the torque converter's adaptability when needed, thus resolving the efficiency-adaptability trade-off.
2Adaptability or versatility
If torque is transmitted through the torque converter in the non-mechanical power path, then variability in torque transmission is improved, but transmission efficiency worsens
Solution Approach 1:
The power transmission system is designed with dual functionality: a mechanical power path for efficient torque transmission and a non-mechanical path with torque converter for variable torque transmission. The clutch mechanism enables universal operation across both paths, allowing the system to select the optimal transmission mode based on operational requirements, thereby achieving both efficiency and variability as needed.
Solution Approach 2:
The system changes the transmission parameter by switching between mechanical and non-mechanical power paths. When high efficiency is required, the mechanical path is selected; when torque variability and adaptability are prioritized, the torque converter path is engaged. This parameter switching resolves the contradiction by allowing optimal performance characteristics to be selected based on operational context.
3Loss of energy
If a switching group with multiple stages is used in the mechanical power path, then transmission efficiency is improved, but device complexity increases
Solution Approach 1:
The switching group with multiple stages is merged with the dual power path architecture, where the clutch that connects the two output shaft units also serves as part of the switching mechanism. This integration reduces the need for separate switching components for each power path, thereby managing device complexity while maintaining the efficiency benefits of the multi-stage mechanical transmission.
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 transmission efficiency by combining mechanical and non-mechanical paths, allowing for high efficiency in torque transmission and variability, with the mechanical path being the primary power path and the torque converter used for adaptation during shifting, minimizing speed changes and abrupt shifts.
Implementation Method 1
A hydraulic unit consisting of a hydraulic pump and a hydraulic motor serves as a non-mechanical drive path. The hydraulic pump is driven by the drive shaft and accordingly creates pressure in the hydraulic fluid. This pressure is used to drive the hydraulic motor
Implementation Method 2
The output shaft is formed from a first and a second output shaft unit, which are connected to one another via a clutch
Implementation Method 3
The mechanical torque transmission is implemented in the form of gearwheel pairs, which can be correspondingly under- or over-translated
Data Source
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AI summary
The invention relates to a power shift transmission, in particular a continuously variable power shift transmission, with an input shaft and an output shaft arranged parallel thereto, wherein a branching unit is arranged on the input shaft, via which a torque acting on the input shaft can be divided into two power paths, wherein a switching group having at least two switching stages is arranged in the first power path and a torque converter is arranged in the second power path.