Four Planetary Gear Transmission for Heavy Vehicles
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Solution Overview
Problem
Existing vehicle transmission arrangements for working machines, such as articulated haulers, require improvements in cost-effectiveness and gear shiftability, with SE 527 108 and US 2008/039266 A1 not fully optimizing the number of components and functionality for efficient operation in heavy load and rough terrain conditions.
Innovation Solution
A transmission arrangement using four planetary gear sets with specific connections between sun gears, planet carriers, and ring gears, along with reduced locking and connecting mechanisms, to achieve nine forward and three reverse gears while minimizing component count and size, and allowing for additional gear options through selective connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If five planetary gear sets are used as in SE 527 108, then sufficient number of gears is provided, but the number of components and cost increase
Solution Approach 1:
The patent merges the functions of five planetary gear sets into four planetary gear sets by implementing direct operative connections between specific components. The fourth planetary gear set's sun gear is directly connected to the third planetary gear set's sun gear, and the fourth planetary gear set's ring gear is directly connected to either the third planetary gear set's planet carrier or the input shaft, eliminating the need for the fifth planetary gear set while maintaining sufficient gear ratios.
Solution Approach 2:
The fourth planetary gear set is designed to perform multiple functions by having its sun gear operatively connected to the third planetary gear set's sun gear and its ring gear operatively connected to either the third planetary gear set's planet carrier or the input shaft. This multi-functional connection allows the fourth planetary gear set to provide both gear reduction and direct drive capabilities, replacing what would traditionally require five separate planetary gear sets.
2Adaptability or versatility
If traditional transmission arrangements are used, then gear functionality is provided, but size and component count increase
Solution Approach 1:
The patent implements a nested arrangement where the fourth planetary gear set is integrated within the existing three planetary gear sets through direct operative connections. The sun gear of the fourth planetary gear set is nested within the sun gear connection of the third planetary gear set, and the ring gear is nested within the planet carrier or input shaft connection, creating a compact transmission arrangement that reduces overall size while maintaining gear shiftability.
3Adaptability or versatility
If more locking mechanisms are added for additional gear options, then gear versatility improves, but device complexity increases
Solution Approach 1:
The patent implements dynamic gear shifting by making the connection between the fourth planetary gear set's ring gear and the third planetary gear set's planet carrier or input shaft selectable rather than fixed. This dynamic connection allows the transmission arrangement to shift between different gear ratios by engaging or disengaging the connection as needed, providing additional gear options without requiring additional locking mechanisms.
Data Source
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AI summary
The present invention relates to a transmission arrangement (100, 200, 300, 400, 500) for a vehicle, the transmission arrangement comprising a first (102), a second (104), a third (106), and a fourth (108) planetary gear set comprising a sun gear, a planet carrier and a ring gear, respectively, wherein said transmission arrangement further comprises a transmission housing (160), an input shaft (136) and an output shaft (1 12), wherein the planet carrier (102P) of the first planetary gear set (102) and the output shaft (112) are operatively connected to each other; the ring gear (102R) of the first planetary gear set (102) and the planet carrier (104P) of the second planetary gear set (104) are operatively connected to each other; the sun gear (102S) of the first planetary gear set (102) and the sun gear (104S) of the second planetary gear set (104) are operatively connected to each other; the ring gear (104R) of the second planetary gear set (104) and the planet carrier (106P) of the third planetary gear set (106) are operatively connected to each other; and two of the sun gear (108S), the planet carrier (108P) and the ring gear (108R) of the fourth planetary gear set (108) are each operatively connected to a respective one of the input shaft (136), the sun gear (106S), the planet carrier (106P) and the ring gear (106R) of the third planetary gear set (106).