CVT Stator Assembly Using Eccentric Gears for Precise Shifting
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Solution Overview
Problem
Current continuously variable transmission (CVT) systems lack improved performance and operational control, particularly in achieving precise speed and torque adjustments, which limits their efficiency and versatility in various applications.
Innovation Solution
The implementation of a stator assembly with a skew-based control system utilizing spherical speed adjusters and eccentric gears, allowing for angular misalignment of planet axes to adjust speed ratios, coupled with a stator driver assembly that facilitates rotation of stators relative to each other, enabling precise control of transmission ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional variator mechanism is used, then basic speed ratio adjustment is achieved, but precise speed and torque control is limited
Solution Approach 1:
The stator is divided into multiple independent stator elements (first stator, second stator, third stator) that can rotate relative to each other about the same axis. Each stator element can be independently controlled to adjust the tilt angle of spherical speed adjusters, enabling precise speed ratio control through incremental adjustments rather than requiring a single complex control mechanism.
Solution Approach 2:
The spherical speed adjusters have tiltable axes of rotation that can be dynamically adjusted by the relative rotation of stator elements. This dynamic tilting mechanism allows continuous adjustment of the speed ratio throughout operation, transforming a static transmission system into a dynamically controllable one that can adapt to varying speed and torque requirements.
2Ease of operation
If spherical speed adjusters with tiltable axes are used, then continuous speed ratio adjustment is achieved, but operational control precision is insufficient
Solution Approach 1:
The control of spherical speed adjusters is segmented into multiple independent stator elements, where each stator (first, second, third stators) controls specific adjusters. This segmentation allows for finer incremental adjustments of the tilt angles, improving control precision while maintaining ease of operation through modular control architecture.
Solution Approach 2:
The stator elements act as intermediary components between the input shaft and the spherical speed adjusters. By introducing these intermediate rotating elements, the system achieves more precise control over the adjuster tilt angles, thereby improving transmission ratio control precision without directly manipulating the speed adjusters themselves.
3Measurement precision
If multiple stator elements are introduced for precise control, then speed and torque adjustment precision is improved, but device complexity increases
Solution Approach 1:
Multiple stator elements (first, second, third stators) are merged into a single integrated stator assembly that rotates together about the common input shaft axis. This merging approach allows precise control of multiple spherical speed adjusters through a coordinated rotation of combined stator elements, achieving high control precision while reducing overall structural complexity compared to completely separate control mechanisms.
Solution Approach 2:
The stator assembly is designed with multi-functionality, where the same rotating stator structure serves to control multiple spherical speed adjusters simultaneously. Each stator element performs dual functions of supporting spherical adjusters and providing the rotational control mechanism, thereby reducing the need for separate control components and lowering overall device complexity.
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 solution enhances the CVT's ability to achieve precise speed and torque adjustments, improving operational control and efficiency across a range of applications, including human-powered vehicles and industrial equipment, by allowing for faster shift rates and more precise control of transmission ratios.
Implementation Method 1
The stator driver couples to a set of eccentric gears. Each of the eccentric gears has a rotational center offset from a geometric center of the eccentric gear.
Data Source
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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).