CVT Backup Chain Switching for Belt Breakage Mobility
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Solution Overview
Problem
Typical continuously variable transmissions face difficulties in power transmission when abnormalities such as chain or belt breakages occur, making it challenging to drive a vehicle to a safe location for repair.
Innovation Solution
A continuously variable transmission system that includes a primary and secondary shaft with a main chain and sub chain, where the sub chain takes over power transmission when the main chain is abnormal, utilizing a power transmission switch mechanism to enable or disable power transfer based on the main chain's condition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single power transmission chain is used in a continuously variable transmission, then the device complexity is reduced, but the reliability decreases when the chain breaks
Solution Approach 1:
The power transmission system is segmented into two independent chains: a main chain for normal operation and a sub chain for emergency power transmission. This segmentation allows the system to maintain reliability by switching to the sub chain when the main chain fails, while keeping each individual chain relatively simple in structure.
Solution Approach 2:
The system changes the operational parameter of power transmission by switching between two different transmission paths (main chain and sub chain). The control unit detects abnormalities in the main chain and changes the transmission parameter by engaging the sub chain, thereby maintaining power transmission capability without increasing the fundamental complexity of each chain.
2Reliability
If a sub chain is added for emergency power transmission, then the reliability improves, but the device complexity increases
Solution Approach 1:
The sub chain is designed with multi-functionality: it serves as an idle component during normal operation (when the main chain is functional) and activates as an emergency power transmission path when the main chain fails. This universal design minimizes the need for separate dedicated emergency components, thereby limiting the increase in overall system complexity.
Solution Approach 2:
The sub chain is pre-installed and positioned within the transmission housing before any failure occurs, but it remains disengaged and inactive during normal operation. The preliminary preparation of the sub chain ensures immediate availability for emergency power transmission without requiring complex real-time assembly or activation mechanisms.
3Reliability
If the sub chain is always engaged, then the reliability is maintained, but the normal shifting performance is degraded
Solution Approach 1:
The power transmission system dynamically adjusts its configuration by engaging or disengaging the sub chain based on real-time operational conditions. During normal operation, the sub chain is disengaged to maintain optimal shifting performance through the main chain. When abnormality is detected, the system dynamically switches to engage the sub chain, ensuring continuous power transmission while preserving normal operational characteristics when needed.
Solution Approach 2:
The sub chain is extracted from the active power transmission path during normal operation and kept as a separate, standby component. This extraction allows the main chain to operate independently without interference, maintaining normal shifting performance. The sub chain can be quickly re-engaged when needed without affecting the main chain's operational characteristics.
Data Source
AI summary
A continuously variable transmission includes a primary shaft, a secondary shaft, a primary pulley, a secondary pulley, a first power transmission member, a primary sprocket, a secondary sprocket, a second power transmission member, and a power transmission switch. The first power transmission member has a loop shape and is wrapped around the primary pulley and the secondary pulley. The primary sprocket is disposed on the primary shaft. The secondary sprocket is disposed on the secondary shaft. The second power transmission member has a loop shape and is wrapped around the primary sprocket and the secondary sprocket. The power transmission switch disables power transmission by the second power transmission member when the first power transmission member is in a normal condition and enables the power transmission by the second power transmission member when the first power transmission member is in an abnormal condition.