Planetary Dual-Motor Transmission for Propulsion and PTO Modes
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Solution Overview
Problem
Off-highway heavy-duty vehicles face challenges in managing power distribution between propulsion and power take-off (PTO) functions, particularly in heavy-duty applications where power demands vary significantly, leading to inflexibility in meeting diverse operational requirements.
Innovation Solution
A dual motor transmission system with two electric motors, a planetary gearset, and multiple wet clutches and one-way clutches, allowing for shifting between two speeds and operational modes to optimize power distribution between propulsion and PTO functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single motor is used for both propulsion and PTO functions with clutch-based power splitting, then device complexity is reduced, but power management flexibility and reliability deteriorate due to inability to independently control power distribution
Solution Approach 1:
The transmission system is segmented into two independent motor units (first motor for PTO, second motor for propulsion) that can operate independently or in combination. This segmentation allows flexible power management where each motor can be controlled separately to meet varying PTO and propulsion power demands without conflicting requirements
Solution Approach 2:
The first motor is designed with multi-functionality to serve both PTO power delivery and propulsion assistance. Through the planetary gearset and clutch mechanisms, the first motor can selectively power the PTO, assist the second motor during high-demand propulsion, or operate independently, providing universal power delivery capability
2Adaptability or versatility
If clutch-based power splitting is used to direct power to PTO or driveshaft, then device complexity is minimized, but power management capability and operational adaptability worsen due to inability to independently control power distribution
Solution Approach 1:
The transmission system employs dynamic clutch control where the first and second clutches can be independently engaged or disengaged based on real-time operational demands. This dynamic control allows the system to adapt between different power distribution modes (PTO-only, propulsion-only, or combined) without mechanical reconfiguration
Solution Approach 2:
The planetary gearset acts as an intermediary mechanism that enables flexible power distribution between the first motor, second motor, and PTO. Through the sun gear, planet gears, and ring gear interactions, the planetary gearset mediates power flow to achieve various operational modes including independent PTO operation and coordinated dual-motor propulsion
3Ease of operation
If separate motors are used for PTO and propulsion, then power management flexibility improves, but device complexity and cost worsen
Solution Approach 1:
The transmission system merges the PTO and propulsion powertrains into a single integrated transmission housing that shares common components including the planetary gearset, clutch mechanisms, and control systems. This merging reduces overall system complexity compared to completely separate systems while maintaining the power management flexibility of independent motor control
Solution Approach 2:
The system is designed with preliminary power delivery capability where the first motor can independently power the PTO without requiring coordination with the second motor. This preliminary action capability ensures that PTO power demands can be met immediately without waiting for propulsion motor availability, improving operational responsiveness
Data Source
AI summary
Methods and systems are provided for an assembly comprising a first motor positioned on a first shaft, a second motor positioned on a second shaft, a first wet clutch selectively coupled to the first shaft, a second wet clutch selectively coupled to an output shaft, a third wet clutch meshed with the output shaft, a brake clutch fixed to a housing of the assembly, a planetary gearset comprising a sun gear positioned on the second shaft, a planet carrier meshed with the second wet clutch and selectively coupled to the third wet clutch, and a ring gear selectively coupled with the brake clutch and meshed with the first wet clutch, and a first one-way clutch and a second one-way clutch opposing the first one-way clutch, the first one-way clutch and the second one-way clutch selectively coupled to the first shaft and mesh with a geartrain to drive an auxiliary shaft.