Planetary Multi-Speed Transmission With 8-Speed Compact Gear Layout
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Solution Overview
Problem
Current multiple speed transmissions face challenges in achieving different gear ratios with improved performance, cost efficiency, responsiveness, and packaging, as existing designs rely heavily on friction clutches and planetary gearsets which can be costly and complex.
Innovation Solution
The design incorporates a system with multiple planetary gearsets and selectively engageable torque-transmitting mechanisms, including brakes and clutches, controlled by an electro-hydraulic system and microprocessor-based transmission control circuit to achieve eight or more speed ratios and one reverse ratio, optimizing gear shifting through fluid pressure control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple planetary gearsets and torque-transmitting mechanisms are used to achieve multiple speed ratios, then the gear ratio range and performance are improved, but the device complexity and packaging difficulty increase
Solution Approach 1:
The patent combines multiple planetary gearsets (first, second, third planetary gearsets) with multiple torque-transmitting mechanisms (first, second, third, fourth torque-transmitting mechanisms) into an integrated transmission system. These components are merged to achieve eight forward speed ratios and one reverse speed ratio through coordinated engagement, resolving the contradiction by creating a unified complex system that delivers extensive gear ratio versatility while managing overall architecture complexity.
Solution Approach 2:
The transmission system is segmented into distinct functional modules: multiple planetary gearsets (each with sun gears, ring gears, and planet gears), multiple torque-transmitting mechanisms (clutches and brakes), and interconnecting members. This segmentation allows each component to be optimized independently while contributing to the overall multiple speed ratio capability, enabling complex functionality to be achieved through coordinated simple elements.
2Productivity
If multiple torque-transmitting mechanisms are selectively engaged to establish multiple speed ratios, then the performance and responsiveness are improved, but the manufacturing cost and complexity increase
Solution Approach 1:
The torque-transmitting mechanisms (clutches and brakes) are designed as multi-functional components that can be selectively engaged to achieve different speed ratios. The same mechanisms serve multiple purposes across different gear ranges, reducing the total number of specialized components needed and thereby lowering manufacturing complexity and cost while maintaining high shifting responsiveness.
Solution Approach 2:
The patent replaces traditional mechanical linkage-based control with electro-hydraulic actuators that are selectively engaged based on desired speed ratios. This substitution reduces mechanical complexity in the control system while improving responsiveness, and allows for more precise and efficient engagement of torque-transmitting mechanisms.
3Adaptability or versatility
If first to fourth planetary gearsets with interconnecting members are used, then the achievable speed ratios are improved, but the packaging constraints and size increase
Solution Approach 1:
The planetary gearsets are arranged in a nested configuration where components of different gearsets are interconnected and share common mounting spaces. The first, second, third, and fourth planetary gearsets are positioned to utilize overlapping radial and axial spaces, with interconnecting members linking corresponding components across gearsets, thereby achieving multiple speed ratios within a compact overall volume.
Solution Approach 2:
The transmission system utilizes three-dimensional spatial arrangement of planetary gearsets and interconnecting members to achieve multiple speed ratios without proportionally increasing transmission size. By distributing components across radial, axial, and longitudinal dimensions, the design packs eight forward and one reverse speed ratio capability into a compact footprint that would be impossible with linear or two-dimensional layouts.
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
This configuration enhances the transmission's ability to achieve a wide range of gear ratios with improved performance, cost efficiency, and responsiveness, while simplifying packaging, enabling efficient operation across various speed conditions.
Implementation Method 1
controlled by an electro-hydraulic system and microprocessor-based transmission control circuit to achieve eight or more speed ratios and one reverse ratio, optimizing gear shifting through fluid pressure control
Data Source
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AI summary
The present disclosure provides a multiple speed transmission having an input member, an output member, a plurality of planetary gearsets, a plurality of interconnecting members and a plurality of torque-transmitting mechanisms. The plurality of planetary gear sets includes first, second and third members. The input member is continuously interconnected with at least one member of one of the plurality of planetary gear sets, and the output member is continuously interconnected with another member of one of the plurality of planetary gear sets. At least eight forward speeds and one reverse speed are achieved by the selective engagement of the five torque-transmitting mechanisms.