Three-Speed Electric Transmission With Planetary Reverse Gearing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The transition to fully electric and hybrid drive systems presents challenges due to the differing speed and torque curves of electric motors compared to internal combustion engines, necessitating the development of more efficient and reliable transmission designs with fewer wear parts that are smaller, lighter, and easier to manufacture.
Innovation Solution
A drive system incorporating a first and second planetary gearset with a sun gear, carrier, and ring gear, along with brakes and a clutch to provide a 1:1 gear ratio, allowing for three forward and three reverse gears without a separate reversing mechanism, and optionally including a hybrid electric motor and internal combustion engine configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional transmission design optimized for internal combustion engines is used, then the speed and torque curves match the engine characteristics, but the transmission becomes larger, heavier, and more complex with more wear parts
Solution Approach 1:
The transmission is divided into two separate planetary gearsets (first and second planetary gearsets) with distinct functions. The first planetary gearset handles torque multiplication for low-speed operation, while the second planetary gearset provides direct drive and reverse functions. This segmentation allows each gearset to be optimized for its specific function, reducing overall complexity and wear parts while maintaining reliability for electric motor applications with different speed and torque curves compared to internal combustion engines
Solution Approach 2:
The second planetary gearset serves multiple functions: providing direct drive (1:1 gear ratio) through clutch engagement, enabling reverse operation through brake engagement on the carrier, and assisting in forward gear operation. This multi-functionality eliminates the need for separate reversing mechanisms and reduces the number of components needed, thereby reducing complexity and weight while maintaining reliability
2Adaptability or versatility
If a separate reversing mechanism is added to provide reverse gears, then reverse operation is enabled, but the transmission complexity and weight increase
Solution Approach 1:
The second planetary gearset is designed to perform multiple functions including reverse operation. By engaging the brake on the carrier of the second planetary gearset while disengaging the clutch, the system achieves reverse gear ratios without requiring a separate reversing mechanism. This integration of reverse functionality into the existing planetary gearset structure reduces complexity and weight while maintaining adaptability for bidirectional operation
Solution Approach 2:
Instead of using a traditional separate reversing mechanism that adds complexity, the patent inverts the approach by using the planetary gearset itself to provide reverse operation through selective braking of the carrier. This inversion of the conventional reversing approach allows reverse gears to be achieved through the same compact planetary structure, reducing overall transmission complexity while enabling versatile bidirectional operation
3Adaptability or versatility
If more wear parts are included to handle different speed and torque curves, then the transmission can accommodate electric motor characteristics, but the transmission becomes larger and heavier
Solution Approach 1:
The transmission is segmented into two planetary gearsets with specialized functions: the first planetary gearset optimized for torque multiplication to handle high-torque low-speed electric motor characteristics, and the second planetary gearset optimized for direct drive and reverse operations. This segmentation allows each gearset to be sized appropriately for its specific function, reducing overall weight while maintaining adaptability to electric motor speed and torque curves through the combined operation of both gearsets
Solution Approach 2:
The transmission uses two planetary gearsets with different gear ratios to provide a range of output speeds and torques, allowing adaptation to electric motor characteristics without requiring excessive wear parts or increased size. The system changes operational parameters by engaging different clutch and brake combinations to achieve various gear ratios, enabling compatibility with electric motor torque curves while maintaining a compact, lightweight design
Data Source
AI summary
A drive system for a vehicle that includes a transmission with three forward and three reverse gears. The transmission is optionally coupled to an electric motor as part of a fully electric or hybrid drive system. The transmission optionally includes a first and a second planetary gearset, a first and a second brake, and a clutch. The system may be configured to separately engage the first or second brakes, or the clutch, and may be arranged to provide separate gear ratios as each is engaged and disengaged separately. A single electric motor may be provided with a single transmission, or multiple electric motors may be included to individually drive multiple separate tires, tracks, or other ground engaging elements. Single or multiple motors may be arranged upstream or downstream of the transmission, and they may be aligned parallel with or perpendicular to a drive axle.