Toroidal CVT Disk Spline and Interference Fit
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Solution Overview
Problem
Conventional toroidal continuously variable transmissions experience fletching wear between outside disks and locking members due to thrust generated by the pressing device, leading to potential damage and poor lubrication.
Innovation Solution
The design incorporates a rotating shaft with outside disks having circular arc-shaped cross sections, support members with skewed pivot shafts, power rollers with spherical convex surfaces, and a locking member that uses a spline fit and interference fit to prevent displacement and reduce elastic deformation, thereby minimizing fletching wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking member is used to prevent displacement of the outside disk, then the reliability is improved, but fletching wear occurs between the outside disk and locking member due to thrust from the pressing device
Solution Approach 1:
A resin layer is introduced as an intermediary between the outside disk and locking member. This resin layer absorbs the thrust force from the pressing device, preventing direct contact and fletching wear between the metal surfaces while maintaining the locking function. The resin acts as a protective mediator that eliminates the harmful wear effect.
Solution Approach 2:
The surface properties of the contact interface are changed by applying a resin coating. This changes the friction and wear characteristics of the interface, transforming it from a high-wear metal-to-metal contact to a low-wear resin-to-metal contact, thereby preventing fletching wear while maintaining reliability.
2Manufacturing precision
If the support rigidity is increased to reduce elastic deformation, then the manufacturing precision is improved, but the device complexity increases
Solution Approach 1:
Instead of uniformly increasing the rigidity of the entire support structure, the invention applies local reinforcement only where needed - specifically at the contact surfaces between the outside disk and locking member. The resin layer provides localized support and rigidity enhancement precisely at the critical interface, minimizing overall device complexity while achieving the precision goal.
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 effectively prevents fletching wear by enhancing support rigidity and reducing elastic deformation, ensuring reliable operation and maintaining a healthy lubrication state.
Implementation Method 1
a spline fit and interference fit to prevent displacement and reduce elastic deformation
Implementation Method 2
reduce elastic deformation
Implementation Method 3
these rollers roll as the input-side disks rotate, and transmit power from the input-side disks to the output-side disks
Implementation Method 4
pre-loaded springs that are disc springs or the like having large elastic force
Implementation Method 5
maintain the minimum required amount of surface pressure at areas of rolling contact
Data Source
AI summary
Fletching wear caused by elastic deformation in the axial direction of an input-side disk 2c due to thrust force of a pressure device is prevented. A female-spline section 13a formed around the middle section in the axial direction of the inner-circumferential surface of a center hole 19 in the input-side disk 2c and a male-spline section 12a formed around the outer-circumferential surface of one end section in the axial direction of an input rotating shaft 1b engage with a spline engagement. A disk-side fitting surface section 22 formed around a portion of the inner-circumferential surface of the center hole 19 in the input-side disk 2c that is adjacent to the other end side of the female-spline section 13a and a shaft-side fitting surface section 23 formed around a portion of the outer-circumferential surface of the input rotating shaft 1b that is adjacent to the other end side of the male spline section 12a are fitted together with an interference fit.