Planetary EV Gearbox Layout for High Torque With Fewer Gears
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Solution Overview
Problem
Electric vehicles with degraded drive systems face reduced drive torque, necessitating multi-speed gearboxes with multiple shiftable transmission ratios for sufficient power delivery, while existing solutions are complex and inefficient.
Innovation Solution
A multi-speed gearbox with an epicyclic gear set and shifting elements allows for discrete transmission ratios, featuring a sun gear, ring gears, planetary gears, and spur-gear stages for efficient torque transmission and compact design, enabling adaptation to high-speed driving motors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If multi-speed gearboxes with multiple shiftable transmission ratios are used to provide sufficient drive torque in degraded systems, then drive torque is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple planetary gear sets (first and second planetary gear sets) with different reduction ratios into a single integrated gearbox structure. The sun gear, planetary gears, and ring gears of both sets share common components, allowing the gearbox to provide multiple transmission ratios (first, second, and third reduction ratios) without requiring separate gearbox units. This merging approach increases drive torque capability while controlling complexity through component sharing.
Solution Approach 2:
The first and second planetary gear sets are designed to perform multiple functions within the same gearbox housing. The first planetary gear set provides the first reduction ratio for high torque requirements, while the second planetary gear set provides the second and third reduction ratios for different operating conditions. Clutch mechanisms enable selective engagement of different gear sets, making the gearbox adaptable to various drive torque requirements without increasing overall structural complexity.
2Adaptability or versatility
If multiple planetary gear sets are used to provide sufficient transmission ratios, then transmission ratio range is improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges two planetary gear sets into a compact integrated structure where components are shared. The first planetary gear set includes a sun gear, first planetary gears, and a first ring gear, while the second planetary gear set includes the same sun gear, second planetary gears, and a second ring gear. This shared component architecture reduces the number of separate manufacturing operations compared to producing two independent gearboxes, while still achieving a wide transmission ratio range through selective engagement.
3Volume of moving object
If a compact gearbox design is implemented, then vehicle space utilization is improved, but heat dissipation capability deteriorates
Solution Approach 1:
The patent arranges the first and second planetary gear sets in a spatial configuration that optimizes both compactness and heat dissipation. The gear sets are positioned to utilize three-dimensional space efficiently within the gearbox housing, with cooling channels and thermal management pathways designed to flow through the compact structure. This dimensional arrangement allows heat generated by multiple planetary gear sets to be dissipated effectively despite the reduced overall volume.
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 gearbox provides a sufficient number of gears with high efficiency and compact construction, ensuring adequate drive torque even in degraded systems, particularly suitable for electric vehicles with high-speed motors.
Implementation Method 1
an epicyclic gearbox having an epicyclic gearbox gear set, wherein this epicyclic gearbox gear set has the following epicyclic gearbox elements, a sun gear, a first ring gear and a second ring gear, at least one first planetary gear, which is preferably in engagement both with the first sun gear and with the first ring gear, and a second planetary gear, which is preferably in engagement with the second ring gear
Data Source
AI summary
A multi-speed gearbox for a vehicle has fewer than 4 shiftable gears and has a gearbox input shaft, a gearbox output shaft, a gearbox housing and a planetary gearbox. The planetary gearbox has a planetary gearbox gear set, which has the following planetary gearbox elements: a sun gear, a first ring gear, and a second ring gear, at least one first planetary gear, which is engaged with both the sun gear and the first ring gear, at least one second planetary gear, which is engaged with the second ring gear, and with a planetary gear carrier, on which the at least one first planetary gear is rotatably mounted. The planetary gearbox gear set has multiple shift elements, which are designed to selectively connect one of the planetary gearbox elements to a further one of the planetary gearbox elements or to the gearbox housing for conjoint rotation and therefore to provide different gears. The at least one second planetary gear is mounted rotatably on the planetary gear carrier and is engaged with the first planetary gear, and the second ring gear can be selectively connected by way of a first of the shift elements to the gearbox housing for conjoint rotation, and the sun gear can be selectively connected by way of a second of the shift elements to the gearbox housing for conjoint rotation.