CVT Movable Sheave Bushing Structure for Eccentric Load Endurance
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Solution Overview
Problem
Existing continuously variable transmissions of the electronically controlled type face challenges in enhancing the load endurance performance of the movable sheave due to the absence of weights for receiving eccentric loads.
Innovation Solution
Incorporating a pair of bushings on the inner peripheral surface of the movable sheave to receive eccentric loads, with spline grooves larger than spline teeth to stabilize the spline fitting and reduce the axial dimension of the rotational shaft, and enclosing lubricant to enhance abrasion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If weights are used to receive eccentric load in a centrifugal type continuously variable transmission, then load endurance performance is improved, but device complexity increases and the structure becomes unsuitable for electronically controlled types
Solution Approach 1:
The patent extracts the load-receiving function from the weights (which are omitted in electronically controlled types) and transfers it to the bushings disposed on both ends of the inner peripheral surface of the boss portion. This allows the bushings to directly receive the eccentric load from the belt, maintaining load endurance performance without requiring complex weight mechanisms.
Solution Approach 2:
The bushings act as intermediary elements between the movable sheave and the rotational shaft, providing a sliding interface that accommodates axial movement while receiving and distributing the eccentric load. This intermediary structure enables the electronically controlled type to achieve load endurance without the complexity of weights.
2Stability of the object's composition
If the spline groove is made larger than the spline tooth in the axial direction, then spline fitting stability is improved and axial dimension of the rotational shaft is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The spline groove is designed with non-uniform dimensions along its length, being larger than the spline tooth in the axial direction at specific locations. This local quality variation provides enhanced spline fitting stability where needed while maintaining overall compactness of the rotational shaft.
3Reliability
If lubricant is enclosed between the pair of bushings, then abrasion resistant performance is improved, but device complexity increases due to additional sealing and retention structures
Solution Approach 1:
The lubricant enclosure function is merged with the existing bushing structure and rotational shaft design. The lubricant is contained within the natural cavities and spaces formed by the bushings, rotational shaft, and movable sheave, eliminating the need for separate sealing mechanisms while still providing effective lubrication to reduce abrasion.
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 enhances the load endurance performance of the movable sheave by distributing eccentric loads effectively and reducing wear, thereby improving the durability and efficiency of the transmission.
Implementation Method 1
The pair of bushings is disposed to be slidable with respect to the rotational shaft in an axial direction of the rotational shaft
Implementation Method 2
A lubricant may be enclosed in between the pair of bushings. In this case, enhancement in abrasion resistant performance can be achieved for the pair of bushings, the rotational shaft, and the movable sheave
Data Source
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AI summary
The present invention relates to a continuously variable transmission (15) of an electronically controlled type; the continuously variable transmission (15) including a rotational shaft (22), a pair of bushings (63, 64), and a movable sheave (60); the pair of bushings (63, 64) being disposed to be slidable with respect to the rotational shaft (22) in the axial direction of the rotational shaft (22); the movable sheave (60) including a boss portion (60b) disposed on the outer peripheral surface of each of the pair of bushings (63, 64) and being moved in the axial direction with sliding of the pair of bushings (63, 64) in the axial direction; the pair of bushings (63, 64) being disposed on both ends of the inner peripheral surface of the boss portion (60b).