Planetary Gearbox Brake Control for Shifting Under Load
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Solution Overview
Problem
Existing parallel shaft gearboxes in automobile vehicles face issues with high frictional losses, inability to shift gears under load, and excessive wear and tear, leading to grinding of gears, due to uneven load distribution and limited gear ratio reduction capabilities.
Innovation Solution
A planetary gearbox design utilizing Planetary Gear Train Units (PGTUs) with sun gears mounted on a driving shaft and Circular Planet Carrier Arms (CPCAs) connected serially, allowing the carrier arms and driven shaft to rotate synchronously by braking specific ring gears, while the rest are set free, enabling efficient gear shifting and reducing wear through optimized load distribution and large gear ratio reductions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a parallel shaft gearbox with a single driven gear is used, then the structure is simple, but the frictional losses are high and gear wear is excessive
Solution Approach 1:
The patent divides the single driven gear into multiple planetary gear units (PGTUs), where each unit handles a portion of the load. This segmentation reduces the frictional losses on each individual gear while maintaining overall system functionality.
Solution Approach 2:
The patent combines multiple planetary gear units with a common sun gear mounted on the driving shaft, creating a unified transmission system that distributes load across multiple planetary gears, thereby reducing overall frictional losses.
2Device complexity
If a parallel shaft gearbox with a single driven gear is used, then the structure is simple, but gear shifting under load is not possible
Solution Approach 1:
The patent employs dynamic control of the planetary gear units through brakes, allowing the system to shift between different operational states (engaged/disengaged) while under load. This enables gear shifting capability that was previously impossible in simple parallel shaft designs.
Solution Approach 2:
The patent pre-positions multiple planetary gear units with their respective brakes, allowing for rapid engagement and disengagement of specific units during operation. This preliminary arrangement enables smooth gear shifting under load without requiring complete system shutdown.
3Device complexity
If a parallel shaft gearbox with a single driven gear is used, then the structure is simple, but load distribution on the gear is uneven causing wear and tear
Solution Approach 1:
The patent segments the total load across multiple planetary gear units, each with its own planetary gears meshing with a common sun gear. This distribution prevents any single gear from bearing excessive load, thereby reducing wear and tear and improving reliability.
Solution Approach 2:
The patent allows each planetary gear unit to have localized characteristics (such as independent brake control and potentially different gear ratios), enabling optimized load distribution across different parts of the system based on specific operational requirements.
4Device complexity
If a parallel shaft gearbox with a single driven gear is used, then the structure is simple, but large reduction gear ratios are very hard to derive
Solution Approach 1:
The patent implements a nested configuration where multiple planetary gear units are arranged around a common sun gear, with each unit contributing to the overall gear ratio. This nested structure enables achieving large reduction ratios through the combined effect of multiple stages without requiring a single complex gear.
Solution Approach 2:
The patent transitions from a single-dimensional (single gear) approach to a multi-dimensional arrangement with multiple planetary gear units operating simultaneously around a common sun gear. This dimensional expansion enables achieving larger gear ratios through parallel operation of multiple units.
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 minimizes frictional losses, allows gear shifting under load, reduces gear wear, and achieves large gear ratio reductions, enhancing the operational efficiency and longevity of the gearbox.
Implementation Method 1
By stopping the motion of the ring gear, using a brake, of a PGTU... By stopping the revolutionary motion of planet gears, using a brake...
Data Source
AI summary
A planetary gearbox comprises a driving shaft, a plurality of planetary gear train units (PGTUs), a carrier arm disc, a driven shaft and at least one brake assembly. Each of the PGTU further comprises a sun gear, at least one planet gear that is meshed to the sun gear and mounted on a planet axle, a ring gear that is meshed to the planet gear and at least one circular planet carrier arm (CPCA) that is coupled to the planet axle. The driving shaft of the planetary gearbox is coupled to the sun gear of the PGTU thereby causing the sun gear to rotate along with it. Further, the CPCA of the PGTU is coupled to the carrier arm disc and the carrier arm disc is further coupled to the driven shaft.