Dual Power-Split Transmission With Planetary Reversing Gear
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Solution Overview
Problem
Existing power-split transmissions for motor vehicles, particularly tracked vehicles, are complex, inefficient in reverse, and limited in maximum achievable speed, often requiring additional superimposed transmissions for steering.
Innovation Solution
A simplified and compact transmission arrangement using duplicate power-split transmissions with a planetary reversing gear, eliminating the need for separate differentials and additional clutches, allowing for higher speeds up to 100 km/h by reversing the direction of rotation through a bevel gear set and planetary reversing gear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If additional superimposed transmissions are added to achieve higher speeds and steering capability, then the speed range and steering functionality are improved, but the device complexity increases significantly
Solution Approach 1:
The patent combines multiple transmission functions (speed variation, steering, forward-reverse) into a single integrated power-split transmission system. The planetary gear arrangement integrates the mechanical branch for speed control with the hydraulic branch for steering and direction control, eliminating the need for separate superimposed transmissions and reducing overall system complexity while achieving speeds up to 100 km/h
Solution Approach 2:
The power-split transmission system performs multiple functions simultaneously: the planetary gear arrangement provides both mechanical speed control and hydraulic steering control, the summing shaft combines power from both branches, and the differential enables both propulsion and directional control. This multi-functional design eliminates the need for additional dedicated transmission components
2Ease of operation
If a conventional transmission design is used for reverse operation, then the reversing functionality is achieved, but reactive power consumption increases and efficiency decreases
Solution Approach 1:
The patent replaces conventional mechanical reversing mechanisms with a hydraulic-based system. The hydraulic units can operate in both directions as motor or pump, allowing reverse operation without the reactive power consumption associated with mechanical clutches and gear reversers. The hydraulic fluid transmission provides smooth bidirectional power flow with minimal energy loss
Solution Approach 2:
The system changes the operational parameters of the hydraulic units to achieve reverse operation. By adjusting the swivel angle of the hydraulic units and controlling the hydraulic flow direction, the system can seamlessly transition between forward and reverse modes without mechanical intervention, maintaining high efficiency in both directions
3Ease of operation
If separate differentials are used for each power-split transmission, then the steering control is improved, but the device complexity and manufacturing costs increase
Solution Approach 1:
The patent merges the differential function into the shared transmission system. A single differential is used to distribute power from the summing shaft to both drive shafts, eliminating the need for separate differentials for each power-split transmission. This integrated approach maintains steering control while reducing the number of components and simplifying the overall system architecture
Solution Approach 2:
The shared differential serves both power-split transmissions simultaneously, providing steering control for the entire vehicle. This universal component performs the same function for both drive shafts that separate differentials would provide individually, reducing complexity while maintaining full steering capability
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 simple, compact, and efficient drive system capable of achieving higher speeds without reactive power consumption, reducing complexity and manufacturing costs, and enabling seamless forward and reverse operation.
Implementation Method 1
a planetary gear arrangement with at least a first sun gear and a second sun gear, a first ring gear and a planet carrier on which double planetary gears are arranged which mesh with the sun gears and with the first ring gear
Implementation Method 2
at least two adjustable hydraulic units which are energetically coupled to each other and can be operated in both directions as a motor or pump
Implementation Method 3
reversing the direction of rotation through a bevel gear set and planetary reversing gear
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a dual power-split transmission (30) with a drive shaft (12), with a first branch (16) comprising a planetary gear assembly (18) with two sun gears (Z1, Z1'), a first ring gear (Z3) and a planet carrier (20) on which double planetary gears (Z2, Z2') are arranged, which mesh with the sun gears and with the first ring gear (Z3), wherein one of the sun gears (Z1) is coupled to the drive shaft (12), with an adjustable second branch (22) which is partially connectable to the first branch (16) via the planetary gear assembly (18) and comprises at least two hydraulic units (H1, H2) which can be energetically coupled to each other and operated in both directions as a motor or pump, and with an output shaft (24) which can be coupled to the drive shaft (12) via the first branch (16) and the second branch (22). is, wherein a planetary gear arrangement (18) is associated with a planetary reversing gear (15),by which the direction of rotation of the first branch (16) can be reversed.