Synchronous IVT-CVT Drivetrain Transition With Minimal Speed Mismatch
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Solution Overview
Problem
Conventional Continuously Variable Transmissions (CVTs) cannot achieve zero output speed, and Infinitely Variable Transmissions (IVTs) often require oversizing due to power recirculation, which is inefficient.
Innovation Solution
A drivetrain configuration that enables synchronous transition between IVT and CVT modes, utilizing a CVT, a forward-reverse clutch assembly, an IVT gear assembly with a planetary gear, and an idler gear assembly to maintain minimal speed mismatch and allow smooth transitions between modes, enabling operation in both forward and reverse directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If IVT is used to achieve zero output speed, then the ability to achieve zero output speed is improved, but the device size increases due to power recirculation
Solution Approach 1:
The drivetrain is segmented into two distinct transmission paths: an IVT path for achieving zero output speed and a CVT path for efficient power transmission. The system can selectively engage either path based on operating conditions, allowing the IVT to operate only when zero speed is required rather than continuously handling all power transmission.
Solution Approach 2:
A clutch assembly acts as an intermediary mechanism to selectively engage or disengage the IVT from the power transmission path. When the CVT is engaged, the IVT is disconnected from power flow, eliminating recirculation losses. The clutch enables smooth transitions between IVT and CVT modes based on operational requirements.
2Speed
If IVT is used to achieve zero output speed, then the ability to achieve zero output speed is improved, but power recirculation occurs reducing efficiency
Solution Approach 1:
The harmful power recirculation is extracted or removed from the system by providing an alternative power transmission path through the CVT. When the CVT is engaged, power flows through this separate path, bypassing the IVT and eliminating recirculation losses entirely.
Solution Approach 2:
The system dynamically switches between IVT and CVT engagement based on operational requirements. The clutch assembly enables real-time reconfiguration of the power transmission path, engaging the CVT for efficient power transmission and disengaging it only when zero output speed is required through the IVT.
3Stability of the object's composition
If synchronous transition between IVT and CVT is implemented, then shift smoothness is improved, but device complexity increases
Solution Approach 1:
The clutch assembly is designed to pre-synchronize the engagement and disengagement of IVT and CVT paths. By coordinating the clutch operation with the transmission mode changes, the system ensures that one path is fully engaged before the other is disengaged, preventing power interruptions and ensuring smooth transitions.
Solution Approach 2:
The clutch assembly serves multiple functions: it engages/disengages the IVT, coordinates the transition between transmission modes, and maintains continuous power flow. This multi-functionality is achieved through a single integrated component rather than multiple separate mechanisms, limiting the increase in complexity.
Data Source
AI summary
A drivetrain for connection between the output of a prime mover and a load is described herein. The drivetrain comprising a CVT including an input connected to the output of the prime mover and an output; a forward-reverse clutch assembly including first and second inputs and an output connectable to the load; the first input of the forward-reverse clutch assembly being connected to the output of the CVT through a CVT clutch. The drivetrain also includes an IVT gear assembly having a first input connected to the output of the prime mover, a second input connected to the output of the CVT and an output connected to the second input of the forward reverse clutch assembly through an IVT clutch; and an idler gear assembly interconnecting the first and second inputs of the forward-reverse clutch assembly.