Ten-Speed Planetary Gear Train Torque Parallel Control
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Solution Overview
Problem
Current 8-speed automatic transmissions face inefficiencies in power performance and fuel consumption due to limited gear shift ratio linearity, with increased components leading to higher costs, weight, and reduced transfer efficiency.
Innovation Solution
A planetary gear train with six coupling elements instead of five planetary gear sets, implementing ten forward speeds and one reverse speed, utilizing a torque parallel method to enhance torque transfer efficiency and durability, and achieve better gear ratio linearity by applying five planetary gear sets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of gear shift stages is increased to improve fuel consumption and power performance, then fuel efficiency and power performance are improved, but the number of components increases leading to higher cost, weight, and reduced transfer efficiency
Solution Approach 1:
The patent merges multiple planetary gear sets into a integrated structure where five planetary gear sets share common elements (sun gears, ring gears, carriers) and are controlled by only six coupling elements. This consolidation achieves 10-speed gear ratios without proportionally increasing component count, directly resolving the contradiction between multistage gear ratios and device complexity
Solution Approach 2:
The six coupling elements serve multiple functions simultaneously - each coupling element can engage with different planetary gear sets to achieve various gear ratios. This multi-functionality allows a reduced number of coupling elements to control a complex 10-speed transmission system, improving fuel efficiency without requiring a proportional increase in component数量
2Device complexity
If conventional planetary gear sets are used with limited coupling elements, then device complexity is reduced, but drag loss increases and power delivery efficiency decreases
Solution Approach 1:
The patent implements a dynamic torque distribution system where the five planetary gear sets are configured in parallel, allowing torque to be dynamically allocated across multiple gear sets based on operating conditions. This dynamic configuration reduces drag loss by optimizing power flow paths while maintaining control with only six coupling elements
Solution Approach 2:
The patent applies torque parallel method where torque is distributed across multiple planetary gear sets simultaneously rather than sequentially. This partial action approach allows some gear sets to carry higher torque loads while others provide support, reducing overall drag loss and improving power delivery efficiency without requiring additional coupling elements
3Device complexity
If shift span is maintained at conventional levels (6.5-7.5), then component count is reduced, but linearity of gear shift stages and power performance are compromised
Solution Approach 1:
The patent changes the fundamental parameter of shift span from conventional 6.5-7.5 to a new range of 9.0 or more by reconfiguring the five planetary gear sets in parallel. This parameter change enables 10 forward speeds with improved linearity of gear shift stages while maintaining control with only six coupling elements, resolving the contradiction between device complexity and manufacturing precision
Data Source
AI summary
A planetary gear train of an automatic transmission for vehicles provides forward ten speed stages and one reverse speed stage. The planetary gear train includes: an input shaft; an output shaft; five planetary gear sets each having three rotation elements; three clutches; three brakes; and nine shafts. Some of the nine shafts may directly connect or selectively connect a plurality of rotation elements among the rotation elements via the clutches, and some of the nine shafts selectively connect selected rotation elements to a transmission housing H via the brakes. In particular, the selected rotation elements are not connected to another rotation element of the five planetary gear sets.