CVT Stator Assembly With Eccentric Gears for Precise Ratio Control
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Solution Overview
Problem
There is a need for improved performance and operational control in continuously variable transmissions (CVTs) with variators that utilize spherical speed adjusters, as existing systems lack efficient mechanisms for achieving desired speed ratios and torque transmission.
Innovation Solution
The CVT system incorporates a stator assembly with radial guide slots, eccentric gears, and a stator driver, allowing for the rotation of stators relative to each other, which adjusts the skew angle of traction planet assemblies to change the speed ratio, along with a shifting mechanism that uses a pulley and planet gears to control the transmission ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a control system is used for the variator to achieve desired speed ratio, then the speed ratio control is improved, but the device complexity increases
Solution Approach 1:
The CVT system uses a flyball governor that automatically detects rotational speed and mechanically adjusts the variator configuration without external control signals. The governor's centrifugal force directly actuates the stator driver, creating a self-regulating system that eliminates complex electronic control while maintaining precise speed ratio control through inherent mechanical feedback.
Solution Approach 2:
The flyball governor provides continuous mechanical feedback on the rotational speed of the input shaft. As speed changes, the governor balls move radially, which through linkage mechanisms adjusts the stator driver position, thereby automatically adjusting the transmission ratio to maintain desired operational characteristics. This closed-loop mechanical feedback replaces complex electronic control systems.
2Adaptability or versatility
If spherical speed adjusters are used in the variator, then the continuously variable ratio capability is improved, but the torque transmission efficiency deteriorates
Solution Approach 1:
The patent replaces traditional spherical speed adjusters that rely on friction-based torque transmission with a mechanical advantage system using stators, stator drivers, and flyball governors. The stator driver acts as a lever arm that mechanically amplifies the force applied to the spherical adjusters, reducing the friction losses and improving torque transmission efficiency while maintaining continuous variable ratio capability.
Solution Approach 2:
The patent utilizes spherical speed adjusters with optimized geometry and curvature distributions. The spherical shape allows for smooth rolling contact and continuous adjustment of the transmission ratio. By carefully designing the spherical geometry and contact surfaces, the system minimizes frictional losses while maintaining the ability to achieve any desired speed ratio within the operating range.
3Ease of operation
If the stator assembly with radial guide slots and eccentric gears is used, then the operational control is improved, but the device complexity increases
Solution Approach 1:
The stator assembly is divided into modular components: stators with radial guide slots, eccentric gears mounted on stator drivers, and flyball governors. Each component performs a specific function and can be independently adjusted or replaced. The segmentation allows for easier maintenance and adjustment while providing precise operational control through coordinated action of the discrete elements.
Solution Approach 2:
The stator assembly incorporates dynamic elements including the flyball governor that automatically adjusts system parameters based on operating conditions. The eccentric gears provide dynamic variation in the transmission ratio as the stator driver rotates, enabling continuous adjustment without complex control mechanisms. The system adapts its configuration in real-time based on rotational speed and load conditions.
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 enhances the CVT's ability to achieve precise speed ratio adjustments and torque transmission, improving operational control and performance by allowing for faster shift rates and precise control of transmission ratios.
Implementation Method 1
a number of eccentric gears coupled to the first stator
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A stator assembly for a continuously variable transmission (CVT) having a plurality of traction planet assemblies (142), the stator assembly comprising: a first stator (160) having a plurality of radial guide slots (161); a second stator (64) coaxial with the first stator (160), the first and second stators (160,164) configured to rotate relative to each other, the second stator (164) having a plurality of radially off-set guide slots (165); characterized in that the stator assembly further comprises: a reaction plate (162) coaxial with the first and second stators (160,164); a plurality of eccentric gears (168) coupled to the plate (162) and the first stator (160); and a stator driver (166) coupled to each of the eccentric gears (168), wherein the eccentric gears (168) are provided with a cam lobe (170) adapted to couple to the reaction plate (162); and wherein each eccentric gear (168) is provided with a reaction lobe (172) that is adapted to couple to the second stator (164); and wherein the cam lobe (170) is provided with a rotational center that is off-set from a rotational center of the reaction lobe (172).