CVT Movable Sheave Drive Mechanism Size Reduction
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Solution Overview
Problem
Existing belt-type electronically-controlled continuously variable transmissions have a complex and costly movable-sheave driving mechanism that can be reduced in size and cost.
Innovation Solution
A simplified mechanism using a spline mechanism for axial movement and a worm gear system with a tangential axis direction, combined with a rotation detection device featuring a pulsar ring and pickup, to reduce the size and complexity of the movable-sheave driving mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a worm gear mechanism driven by a motor through a reduction gear is used to rotate and axially move the movable collar, then the movable sheave can be precisely controlled, but the mechanism becomes complex and costly
Solution Approach 1:
The patent extracts the reduction gear from the transmission system by using a belt-type continuously variable transmission instead of a gear-based transmission. This eliminates the need for complex reduction gears while maintaining precise control through the variable ratio belt mechanism
Solution Approach 2:
The patent replaces the mechanical worm gear and reduction gear system with a belt-driven continuously variable transmission system. The movable collar is rotated and axially moved through the belt mechanism rather than through complex mechanical gears, simplifying the overall structure
2Manufacturing precision
If a complex movable-sheave driving mechanism is used, then the transmission can be precisely controlled, but the size of the transmission increases
Solution Approach 1:
The patent merges the functions of the movable collar rotation, axial movement, and groove width adjustment into a single integrated belt-driven mechanism. The movable collar performs multiple functions through the variable ratio belt transmission, eliminating the need for separate mechanisms for each function
Solution Approach 2:
The patent uses a dynamically adjustable belt-type continuously variable transmission system that can continuously change the gear ratio by adjusting the position of the movable sheave. This dynamic mechanism replaces static gear systems with multiple discrete components, reducing overall transmission size
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
The solution reduces the size and cost of the movable-sheave driving mechanism, allows for efficient detection of the movable sheave's position, and prevents contamination and overheating of the electric motor, while maintaining the transmission's efficiency and compactness.
Implementation Method 1
a slider that is provided coaxially with the movable sheave and that is connected so as to be axially-movable and rotationally non-movable with respect to the housing via a spline mechanism
Implementation Method 2
a wheel that is provided coaxially with the movable sheave and screwed to the slider using a thread
Implementation Method 3
a worm wheel; a worm gear of which an axis direction is a tangential direction of the worm wheel and which is screwed to the worm wheel
Data Source
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AI summary
A belt-type electronically-controlled continuously variable transmission (5) that includes a housing, a primary pulley (51) having a movable sheave (53), a secondary pulley having a driven sheave, a belt (54) that is wound between the primary pulley (51) and the secondary pulley, a slider (70) that is provided coaxially with the movable sheave (53) and that is connected so as to be axially-movable and rotationally non-movable with respect to the housing and to be axially non-movable and rotationally movable with respect to the movable sheave (53), a worm wheel (71) that is provided coaxially with the movable sheave (53) and screwed to the slider (70) using a thread, a worm gear (72) of which an axis direction is a tangential direction of the worm wheel (71) and which is screwed to the worm wheel (71), and an electric motor having the worm gear (72) mounted to an output shaft thereof.