CVT Actuator Sheave Control for Speed Switching and Belt Wear
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing continuously variable transmission systems for vehicles face complexity and increased cost due to the need for multiple torque cam mechanisms for speed switching and require a centrifugal clutch, which increases component count and manufacturing costs, while also causing belt wear due to friction issues during braking.
Innovation Solution
A continuously variable transmission control system that uses an electricity-driven actuator to adjust the width between moveable and fixed sheaves, allowing for speed relationship switching without multiple torque cam mechanisms and eliminating the need for a centrifugal clutch by releasing belt pinching during braking, thus reducing wear and component count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple torque cam mechanisms are used for speed switching, then speed relationship switching capability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The electricity-driven actuator serves multiple functions: it adjusts the moveable sheave position for continuous speed ratio variation and can be controlled to achieve discrete speed relationship switching. This single multi-functional component replaces what would traditionally require multiple specialized torque cam mechanisms, thereby reducing structural complexity while maintaining speed switching capability.
Solution Approach 2:
The patent replaces the mechanical torque cam switching mechanism with an electricity-driven actuator system. The actuator, controlled by a control device, adjusts the moveable sheave position based on control signals that incorporate both continuous position information and discrete speed relationship switching commands. This substitution eliminates the need for complex mechanical switching structures while achieving the same functional outcome.
2Reliability
If a centrifugal clutch is added to reduce belt wear during braking, then belt durability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts and eliminates the centrifugal clutch component from the traditional CVT system by using the electricity-driven actuator to directly control the moveable sheave position during braking. The actuator receives control signals that command it to adjust the sheave position to reduce friction between the belt and pulleys during deceleration, thereby protecting the belt without requiring a separate centrifugal clutch mechanism.
Solution Approach 2:
The electricity-driven actuator serves as an intermediary device that mediates between the control system and the belt-pulley interaction during braking. Instead of using a centrifugal clutch to physically disconnect power transmission, the actuator actively adjusts the moveable sheave position to control friction levels, providing a softer, more controllable protection mechanism for the belt.
3Device complexity
If electricity-driven actuator is used instead of hydraulic or mechanical structures, then manufacturing cost and complexity are reduced, but control precision requirements increase
Solution Approach 1:
The control device receives control signals that include both continuous position information from position detection means and discrete speed relationship switching commands. This feedback mechanism allows the control device to precisely control the electricity-driven actuator's output, ensuring accurate moveable sheave positioning and discrete speed ratio switching, thereby meeting the precision requirements despite the simplified structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient speed relationship switching among rotational speeds of drive and driven pulleys without complex torque cam mechanisms and reduces belt wear by releasing pinching during braking, thereby simplifying the system and lowering manufacturing costs.
Implementation Method 1
an electricity-driven actuator changing an width between the moveable sheave and the fixed sheave by movement of the moveable sheave
Implementation Method 2
a belt type continuously variable transmission device having a belt suspended between a drive pulley on the side of a motive power source and a driven pulley on the side of a wheel
Data Source
AI summary
A continuously variable transmission control system includes a continuously variable transmission device having an electricity-driven actuator that changes an width between a moveable sheave and a fixed sheave in at least one pulley of a drive pulley and a driven pulley, and a control device that controls driving of the electricity-driven actuator. The control device selects, from a plurality of speed relationships, each of which is a relationship between an input shaft rotational speed of the drive pulley and an output shaft rotational speed of the driven pulley, one speed relationship according to an input of a switch command signal or a drive state of the vehicle, and changes the width between the moveable sheave and the fixed sheave based on the selected speed relationship and detected values of the input shaft rotational speed and the output shaft rotational speed.