Multi-speed Transmission with Four Planetary Gearsets
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Solution Overview
Problem
Existing multi-speed transmissions for motor vehicles, such as those with four planetary gearsets and six shift elements, face limitations in achieving a wide range of gear ratios efficiently, leading to increased component loads and transmission losses.
Innovation Solution
A transmission design incorporating four planetary gearsets with specific element configurations and six shift elements, allowing for selective actuation to achieve ten forward gears and one reverse gear by permanently engaging certain elements to minimize losses and optimize gearing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a multi-speed transmission with four planetary gearsets and six shift elements is used to achieve a wide range of gear ratios, then the adaptability is improved, but the device complexity increases
Solution Approach 1:
The transmission is divided into four separate planetary gearsets (first, second, third, and fourth), each capable of independent operation. This segmentation allows each gearset to contribute to different gear ratios, enabling a wide range of 10 forward gears and 1 reverse gear to be achieved through selective engagement of these modular units.
Solution Approach 2:
The transmission employs six shift elements that can be selectively actuated to dynamically reconfigure the power flow paths through the planetary gearsets. This dynamic engagement and disengagement of shift elements allows the transmission to adapt between different gear ratios and operating modes, achieving versatility without permanently fixing the structure for each gear configuration.
2Adaptability or versatility
If multiple shift elements are used to achieve different gear ratios, then the adaptability is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent combines multiple planetary gearsets into a single integrated transmission unit with shared components. The first element of the first planetary gearset and the first element of the second planetary gearset are rotatably engaged with each other, and the second element of the first planetary gearset and the third element of the fourth planetary gearset are rotatably engaged, creating a compact merged structure that reduces manufacturing complexity despite the presence of multiple gearsets and shift elements.
Solution Approach 2:
The planetary gearsets are designed with universal element configurations where elements can serve multiple functions across different gearsets. The rotatable engagement between elements of different gearsets allows a single element to participate in multiple power flow paths and gear ratio configurations, simplifying the overall manufacturing process.
3Ease of manufacture
If conventional planetary gearset arrangements are used, then the ease of manufacture is improved, but the transmission losses increase
Solution Approach 1:
The transmission is designed with predetermined optimal engagement configurations for the planetary gearsets. The specific arrangement where the first element of the first planetary gearset and the first element of the second planetary gearset are rotatably engaged, and the second element of the first planetary gearset and the third element of the fourth planetary gearset are rotatably engaged, represents a pre-optimized configuration that minimizes transmission losses while maintaining ease of manufacture using standard planetary gearset components.
4Adaptability or versatility
If more planetary gearsets are added to increase gear ratios, then the adaptability is improved, but the component loads increase
Solution Approach 1:
By dividing the transmission into four separate planetary gearsets, the total torque and power load is distributed across multiple independent gear transmission paths. Each planetary gearset handles a portion of the overall load, preventing any single component from being overloaded while still achieving the capability of 10 forward gears and 1 reverse gear through selective engagement.
Solution Approach 2:
The dynamic engagement of shift elements allows the transmission to optimally distribute loads across different planetary gearsets based on the required gear ratio. During operation, the control system can selectively engage specific shift elements to route power through optimal paths, balancing component loads and preventing excessive stress on individual elements.
Data Source
AI summary
A transmission (G) for a motor vehicle. The transmission (G) comprises a transmission input (GW1-A), a transmission output (GW2-A), first, second, third and fourth planetary gearsets (P1, P2, P3, P4) and first, second, third, fourth, fifth and sixth shift elements (B1, B2, K1, K2, K3, K4). Ten forward gears and one reverse gear can be achieved between the transmission input (GW1-A) and the transmission output (GW2-A) by selectively operating the six shift elements (B1, B2, K1, K2, K3, K4). A drive train for a motor vehicle having such a transmission (G) is also disclosed.