Vehicle Gearbox Reducing Reverse Torque and Dimensions
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Solution Overview
Problem
Current range gearboxes in vehicles face challenges in achieving a balance between compact size, low weight, and effective torque transmission, which affects driveability in reverse directions and increases manufacturing costs due to the number of components.
Innovation Solution
A gearbox design incorporating a split gearbox and a range gearbox with a planetary gear that allows shifting into low, high, and reverse gear positions, featuring a combined ratio spread greater than 5 and a gear ratio less than 4:1 in reverse gear, utilizing axially movable coupling sleeves to optimize gear ratios and reduce component count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the planetary gear in the range gearbox is designed with a larger diameter to transmit torque effectively, then the torque transmission capability is improved, but the gearbox dimensions and weight increase
Solution Approach 1:
The patent changes the gear ratio parameter of the planetary gear to less than 4:1 in reverse gear position, which allows the planetary gear to maintain adequate torque transmission capability while reducing its diameter and overall gearbox dimensions. This parameter optimization resolves the contradiction between strength and volume.
2Adaptability or versatility
If the reverse gear is arranged in the main gearbox, then the reverse gear functionality is achieved, but the main gearbox length and vehicle weight increase
Solution Approach 1:
The patent makes the range gearbox multi-functional by enabling it to provide both range multiplication (low/high range) and reverse gear functionality. This eliminates the need for a separate reverse gear in the main gearbox, thereby reducing the main gearbox length while maintaining all necessary functions.
3Volume of moving object
If the planetary gear is designed with a higher gear ratio to reduce dimensions, then the gearbox size is reduced, but the torque transmission capability in reverse direction is insufficient
Solution Approach 1:
The patent optimizes the gear ratio parameter to be less than 4:1 (rather than higher), which balances the contradiction by providing adequate torque transmission in reverse while maintaining compact dimensions. The specific parameter range achieves both goals simultaneously.
4Manufacturing precision
If more components are used in the range gearbox to achieve precise gear ratios, then the gear ratio precision is improved, but the manufacturing cost and component count increase
Solution Approach 1:
The patent makes the planetary gear perform multiple functions: providing both low/high range multiplication and reverse gear capability through axial displacement of the ring gear. This eliminates the need for additional components that would otherwise be required to achieve reverse gear functionality, thereby reducing component count while maintaining precision.
Data Source
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AI summary
The invention relates to a gearbox (2) for vehicles (1), comprising a split gearbox (15C), a main gearbox (15A) and a range gearbox (15B), which range gearbox (15B) is shiftable into a low range gear, a high range gear and a reverse gear; the range gearbox (15B) comprising a planetary gear (14), which may be shifted into a reverse gear. The split gearbox (15C) and the main gearbox (15A) are together arranged to have a combined ratio spread larger than 5, in that the split gearbox (15C) and the main gearbox (15A) are together arranged to have a combined largest gear ratio over 4:1, and in that the planetary gear (14) in the range gearbox (15B) is arranged to have a gear ratio less than 4:1 when shifted into the reverse gear. The invention also relates to a vehicle (1), which is provided with such a gearbox (2).