CVT Inner Race Preload and Torsional Backlash Control
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Solution Overview
Problem
Existing continuously variable transmission (CVT) designs experience issues with backlash and torque spikes during torque reversals, leading to potential damage and wear due to insufficient torque resistance and reactive clamping mechanisms.
Innovation Solution
Implementing a torque-sensitive coupling mechanism with a torsion damping mechanism, such as a preload spring or disk springs, to provide increased torque resistance and manage backlash during torque transitions, including a torque-sensitive inclined plane structure and ball or roller ramps for axial displacement control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a torque-sensitive coupling mechanism with torsion damping is implemented, then torque resistance and backlash management are improved, but device complexity increases
Solution Approach 1:
The patent combines the torsion damping mechanism with the torque-sensitive coupling mechanism into a single integrated assembly. The torsion damping mechanism is positioned between the input shaft and the torque-sensitive coupling, allowing both functions to work together in managing torque reversals and backlash without requiring separate independent systems.
Solution Approach 2:
The torsion damping mechanism applies preliminary torque resistance before torque reversals occur. By pre-loading the system with damping elements (such as springs or viscous dampers), the mechanism is prepared to absorb and mitigate torque spikes and backlash during reversal events, preventing damage before it occurs.
2Duration of action of stationary object
If torsion damping mechanism is added to manage backlash, then component wear is reduced, but device complexity increases
Solution Approach 1:
The torsion damping mechanism serves as a cushioning element that is pre-positioned in the torque transmission path. During normal operation, it maintains a ready state that allows it to absorb and dampen torque spikes and backlash during reversals, protecting components from impact damage and excessive wear without requiring active control.
3Manufacturing precision
If axial displacement control mechanisms are implemented, then transmission ratio precision is improved, but device complexity increases
Solution Approach 1:
The torque-sensitive coupling mechanism incorporates feedback through its design, where the coupling elements respond to torque magnitude and direction, automatically adjusting the axial displacement of the races. This passive feedback mechanism maintains precise transmission ratios by compensating for backlash and torque-induced displacements without requiring external sensors or active control systems.
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 reduces backlash and torque spikes, enhancing CVT performance by applying proportional axial load and torsional resistance, thereby minimizing component wear and damage during torque reversals.
Implementation Method 1
a torsion damping mechanism operatively coupled to the torque sensitive inclined plane mechanism to apply torque sufficient to reduce backlash during torque transitions
Implementation Method 2
such as a preload spring or disk springs
Implementation Method 3
a torque-sensitive inclined plane structure and ball or roller ramps for axial displacement control
Implementation Method 4
ball or roller ramps for axial displacement control
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A radially inner race for a continuously variable transmission includes a first inner race structure and a second inner race structure spaced along an axis wherein at least one of the first inner race structure or the second inner race structure is axially movable. A sun shaft is coupled to the radially inner race and planetary members in rolling contact with the radially inner race, and a torsion damping mechanism is coupled to the first inner race structure to apply torque between the first inner race structure and the sun shaft to reduce a transition amplitude during a torque impulse.