Nested Dual-Input Vehicle Transmission for Compact Layout
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Solution Overview
Problem
Existing power transmitting apparatuses for vehicles face challenges in minimizing length, enhancing drivability, and improving fuel economy while preventing distortion of step ratios and enabling skip shifting between high and specific shift speeds.
Innovation Solution
A power transmitting apparatus featuring a variable connecting device with two clutches and input/output shafts equipped with specific gear configurations and synchronizer modules, allowing for efficient torque transmission and parallel output shafts to achieve seven forward speeds with minimized component count, enabling skip shifting and maintaining drivability and fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a conventional single-clutch transmission design is used, then the structure is simpler, but the transmission length cannot be minimized and drivability is compromised
Solution Approach 1:
The transmission is divided into two independent input shafts (first and second input shafts) each with dedicated clutches, allowing parallel torque transmission paths. This segmentation enables compact layout by distributing components across two shafts rather than one, reducing overall transmission length while maintaining functional simplicity through modular architecture
Solution Approach 2:
The first and second input shafts are arranged coaxially with the first input shaft positioned inside the second input shaft, creating a nested configuration. This nesting allows both shafts to occupy the same radial space, significantly minimizing the transmission's external dimensions and length without increasing structural complexity
2Productivity
If traditional gear arrangements are used, then the gear train is simpler, but step ratio distortion occurs and fuel economy deteriorates
Solution Approach 1:
The transmission employs a dynamic gear configuration where seventh speed gears are selectively engageable with either the first or second input shaft depending on operating conditions. This dynamic arrangement allows optimization of step ratios for fuel economy by choosing the most efficient torque path, while the selective engagement mechanism keeps the overall structure manageable through conditional rather than permanent complexity
3Ease of operation
If highest shift-speed to specific shift-speed skip shifting is enabled, then drivability is enhanced, but the control system becomes more complex
Solution Approach 1:
The transmission pre-configures multiple seventh speed gears positioned to engage with different input shafts, preparing multiple torque transmission paths in advance. This preliminary arrangement enables the control system to execute skip shifting by simply selecting among pre-positioned gears rather than executing complex real-time gear manipulations, thereby enhancing drivability while limiting control complexity through pre-planned configurations
Data Source
AI summary
A power transmitting apparatus for a vehicle may include a variable connecting device including a first clutch and a second clutch and selectively outputting torque of an engine through the first clutch and/or the second clutch, an input device including first and second input shafts selectively connected to the engine through the first and second clutches, and a speed output device including a first output shaft, a first speed output unit with first and second synchronizer modules, a second output shaft, and a second speed output unit with third, fourth, and fifth synchronizer modules. In the power transmitting apparatus, one seventh speed gear engaged with any one input gear on the first input shaft and another seventh speed gear engaged with any one input gear on the second input shaft are disposed on the first or second output shaft.