Toothed CVT Slack-Side Tensioning for Smooth Teeth Re-Engagement
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Solution Overview
Problem
Existing CVT systems face challenges in maintaining smooth tooth re-engagement due to significant Transmission Belt Teeth Compression and stretching, particularly under heavy load conditions, leading to misalignment and variations in tension that affect the transmission ratio.
Innovation Solution
The CVT employs a Transmission Diameter Compensating Mechanism to increase the diameter of the Driving Cone when torque increases, and a slack-side Tensioning Pulley to maintain constant tension in the slack-side of the belt, along with a slack-side Constrainer to manage slack as needed, minimizing angle changes at the Tensioning Pulley and using incremental diameter changes for each transmission ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the CVT uses a conventional tensioning system without diameter compensation, then the structure is simpler, but the teeth re-engagement becomes misaligned under heavy load due to belt compression and stretching
Solution Approach 1:
The patent changes the transmission diameter parameter dynamically through the Transmission Diameter Compensating Mechanism. When torque increases causing belt compression and stretching, the mechanism automatically increases the transmission diameter of the driving cone to compensate, maintaining proper teeth alignment and re-engagement without requiring complex structural modifications to the entire system
Solution Approach 2:
The patent replaces the conventional tensioning-only approach with a hybrid system that combines tensioning (via the Tensioning Pulley) and diameter compensation (via the Transmission Diameter Compensating Mechanism). This substitution of the pure mechanical tensioning system with an enhanced system that modifies geometric parameters resolves the alignment issue while keeping the overall structure manageable
2Manufacturing precision
If the CVT increases transmission diameter to compensate for belt stretching under heavy load, then teeth re-engagement improves, but the tension in the transmission belt varies
Solution Approach 1:
The Tensioning Pulley acts as an intermediary element between the driving and driven cones. It actively manages the slack side of the transmission belt, maintaining constant tension despite the diameter changes made by the Transmission Diameter Compensating Mechanism. This intermediary component absorbs the tension variations that would otherwise occur when the transmission diameter is adjusted for teeth alignment
Solution Approach 2:
The system performs preliminary compensation by increasing the transmission diameter before significant misalignment occurs. The Transmission Diameter Compensating Mechanism anticipates the alignment issues that would result from belt compression and stretching under increasing torque, and proactively adjusts the diameter to prevent misalignment while the Tensioning Pulley pre-maintains proper tension levels
3Device complexity
If the CVT uses fixed transmission diameter, then the structure is simpler, but the transmission ratio varies due to cone misalignment under varying torque
Solution Approach 1:
The patent transitions from a static transmission diameter to a dynamic one that automatically adjusts with torque conditions. The Transmission Diameter Compensating Mechanism enables the driving cone's transmission diameter to change dynamically in response to varying torque loads, ensuring that the cones remain properly aligned and the transmission ratio stays consistent throughout operation, while keeping the structural complexity manageable through integrated design
4Ease of operation
If the Tensioning Pulley allows angle changes to manage slack, then slack management is easier, but the teeth re-engagement becomes less smooth due to tension variations
Solution Approach 1:
The Tensioning Pulley operates with feedback control to maintain constant slack side tension. It continuously monitors and adjusts the tension levels, preventing the tension variations that would occur if the pulley simply allowed angle changes to manage slack. This feedback mechanism ensures smooth teeth re-engagement while still providing effective slack management through active tension regulation rather than passive angle adjustment
Data Source
AI summary
A toothed CVT using a Cone with One Torque Transmitting Member that is coupled by a Transmission Belt to another Cone with One Torque Transmitting Member for which teeth re-engagement between the Torque Transmitting Members and their Transmission Belt is improved. Said CVT uses a slack-side Tensioning Pulley in order to maintain the tension in the slack-side of the Transmission Belt almost constant so as to ensure smooth re-engagement of the Driven Cone; and a Transmission Diameter Compensating Mechanism, which increases the Transmission Diameter of the Driving Cone when the torque being pulled by the Driving Cone is increased, in order to compensate for an increase in “Transmission Belt Teeth Compression” and an increase in “stretching of the tense-side of the Transmission Belt”, due to an increase in tension in the tense-side of the Transmission Belt when an increased torque is transmitted; to ensure smooth re-engagement of the Driving Cone.