Toroidal CVT Bearing Preload for Compact, Stable Power Transfer
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Solution Overview
Problem
Conventional toroidal continuously variable transmissions face challenges in achieving compactness while maintaining transmission efficiency due to variations in traction coefficient and surface pressure between disk elements and power rollers, and the use of thrust angular ball bearings increases the size of the transmission.
Innovation Solution
The toroidal continuously variable transmission employs radial rolling bearing units with preloading mechanisms to support the inside disk, allowing relative rotation and applying axial preload to maintain consistent preloading and prevent excessive loading, thereby stabilizing the transmission efficiency and compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If thrust angular ball bearings are used to support the inside disk, then the transmission can rotate freely, but the size of the transmission increases
Solution Approach 1:
The patent changes the bearing type from thrust angular ball bearings to radial rolling bearings, altering the support mechanism parameters. This substitution reduces the bearing size while maintaining rotational capability through the combination of radial bearing and preloading mechanism
Solution Approach 2:
The support system is segmented into two functional parts: radial rolling bearings for rotational support and a preloading mechanism for axial positioning. This segmentation allows each component to be optimized independently, reducing overall size while maintaining functionality
2Volume of moving object
If radial rolling bearings are used to support the inside disk, then the transmission size is reduced, but dimensional differences cause uneven preloading
Solution Approach 1:
The preloading mechanism incorporates elastic elements that provide dynamic adjustment capability. This allows the system to automatically compensate for dimensional variations in radial rolling bearings, maintaining uniform preloading conditions despite manufacturing tolerances
Solution Approach 2:
The preloading mechanism is designed to self-adjust and compensate for bearing dimensional differences without external intervention. The elastic preloading elements automatically adapt to variations in bearing dimensions, ensuring consistent preloading force distribution
3Stability of the object's composition
If the inside disk is tightly supported, then positional stability is improved, but transmission efficiency decreases due to excessive preloading
Solution Approach 1:
The patent optimizes the preloading force parameter to achieve the optimal balance between positional stability and transmission efficiency. By carefully selecting the preloading magnitude, the system maintains sufficient stability while minimizing energy loss from excessive preloading
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
This configuration maintains transmission efficiency and durability by absorbing dimensional differences and preventing uneven preloading, allowing for a more compact design without compromising performance.
Implementation Method 1
a pair of rolling bearing units which includes a radial rolling bearing capable of supporting an axial load
Implementation Method 2
a preloading mechanism that elastically presses the outer ring or the inner ring of the radial rolling bearing in the axial direction
Implementation Method 3
absorbing dimensional differences and preventing uneven preloading
Data Source
AI summary
The present disclosures relates to a toroidal continuously variable transmission which includes: a rotating shaft; a pair of outside disks supported by a rotating shaft to rotate in synchronization with the rotating shaft; an inside disk supported by the rotating shaft to rotate relative to the rotating shaft; a pair of rolling bearing units, each including a radial rolling bearing capable of supporting an axial load to support the inside disk so that relative rotation with respect to the rotating shaft is possible; a plurality of power rollers arranged between the axial inside surfaces the outside disks and the axial outside surfaces of the inside disk to transmit power between them; and a preloading mechanism elastically pressing the outer ring of the radial rolling bearing in the axial direction.