Gearbox Assembly With Branched Power Flow Paths
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Solution Overview
Problem
Existing transmission arrangements for heavy commercial vehicles face challenges in achieving a large gear spread while maintaining low mass inertia and minimizing the speeds of rotating components, which is crucial for efficient gear shifting and reducing wear.
Innovation Solution
A transmission arrangement that includes a main manual transmission with multiple gear ratios and an epicyclic gear, connected via two shafts, allowing power flow to branch into multiple paths with switching points, enabling efficient gear shifting and generation of additional gears through power flow winding, thus achieving a large gear translation with low inertia and efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the transmission is designed with high gear ratios for lower gears to achieve wide gear ratio spread, then the gear ratio spread is improved, but the rotational speeds of transmission components become too low which increases inertia and slows down gear shifting
Solution Approach 1:
The transmission is divided into two independent subsystems: a main transmission with a limited number of gear ratios and a planetary transmission with multiple selectable gear ratios. This segmentation allows each subsystem to operate optimally - the main transmission handles high-speed operations while the planetary transmission provides low-speed gear multiplication, resolving the contradiction between wide gear spread and component speed
Solution Approach 2:
The patent introduces a second dimension of gear ratio selection through the planetary transmission, which can be independently combined with the main transmission ratios. This creates a two-dimensional gear ratio matrix that achieves wide gear spread without requiring excessively low rotational speeds in any single transmission path
2Adaptability or versatility
If the transmission is designed with high gear ratios for lower gears, then the gear ratio spread is improved, but the inertia of rotating components increases which slows down gear shifting
Solution Approach 1:
By segmenting the transmission into main transmission and planetary transmission subsystems, the patent enables independent optimization of each subsystem's inertia characteristics. The planetary transmission uses a compact epicyclic gear structure with low inertia that can rapidly switch between ratios, while the main transmission handles the bulk power transmission, collectively achieving wide gear spread with minimal shifting time
Solution Approach 2:
The planetary transmission acts as an intermediary between the drive motor and the final drive system, providing a compact set of gear ratios that can be quickly engaged or disengaged. This intermediary subsystem reduces the inertia burden on the main transmission and enables rapid gear changes without affecting the overall wide gear ratio spread
3Adaptability or versatility
If multiple switching points are introduced in the power flow paths, then additional gears and gear ratio stages can be generated, but the device complexity increases
Solution Approach 1:
The patent segments the transmission control into two independent switching systems: one for the main transmission and another for the planetary transmission. Each switching system controls its own clutch pack independently, simplifying the control logic despite the presence of multiple switching points. The segmented architecture allows for modular addition of gear ratios without proportionally increasing overall system complexity
4Adaptability or versatility
If a planetary transmission is added to the main transmission, then additional gear ratios and winding paths are achieved, but the transmission size and manufacturing cost increase
Solution Approach 1:
The planetary transmission is nested within the existing main transmission architecture, sharing common mounting spaces and power flow paths. The compact epicyclic gear structure of the planetary transmission fits within the transmission housing without requiring a proportional increase in overall transmission volume, achieving high gear ratio multiplication in a space-efficient manner
Data Source
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AI summary
Transmission arrangement (28) for a drive train (20) of a vehicle (10) for connecting a drive motor (22) to a drive unit (24) of the vehicle, comprising a main transmission (50) with several gear ratios (60, 66, 70, 74), wherein several switching states of the main transmission (50) can be selected by means of switching points (62, 72) of one or more gear ratios (60, 66, 70, 74), and a planetary gear unit (40), wherein the main transmission (50) and the planetary gear unit (40) are connected to each other via two connecting shafts (521, 522) or can be connected as required, wherein in one or more switching states of the main transmission (50) a power flow from the drive motor (22) in at least one section of the transmission arrangement (30) runs via several branched power paths to the drive unit (24),and wherein in at least one switching state the power flow in at least one of the branched power paths passes through at least two switching points (62, 72).