Infinitely Variable Transmission Carrier Mechanism
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Solution Overview
Problem
Current continuously variable transmissions (CVTs) and infinitely variable transmissions (IVTs) face challenges in increasing efficiency, reducing cost, size, and complexity, while providing flexible packaging and simplified operation.
Innovation Solution
The development of an infinitely variable transmission (IVT) system with a shifting mechanism featuring traction planet assemblies, carrier members with radially offset slots, and a carrier driver nut that translates axially to rotate the carrier members, allowing for precise control of transmission ratios through a skew-based control system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a continuously variable transmission (CVT) is used to provide every fractional ratio in a given speed ratio range, then the transmission can deliver intermediate speed ratios (e.g., 1:1.5, 1:1.75), but the device complexity and cost increase compared to stepped transmissions
Solution Approach 1:
The patent replaces traditional mechanical CVT components (pulleys, belts, chains) with a planetary gear-based mechanism using sun gears, planet gears, and carrier members. This mechanical substitution maintains continuous variability while simplifying the overall structure and reducing complexity associated with conventional CVT designs.
Solution Approach 2:
The transmission is divided into modular planetary gear sets with multiple sun gears, planet gears, and carrier members. Each planetary gear set functions as an independent module that can be controlled individually, allowing continuous ratio adjustment through coordinated operation of these segmented components while keeping each module relatively simple.
2Adaptability or versatility
If an infinitely variable transmission (IVT) is used to deliver zero output speed with steady input speed, then the transmission can produce an infinite set of speed ratios, but the device complexity increases due to additional gearing and clutches
Solution Approach 1:
The patent extracts and eliminates the need for additional clutches and complex gearing by using a planetary gear-based IVT design. The carrier member's ability to rotate and lock independently allows direct control of the planet gears, achieving infinite variability without requiring separate clutch mechanisms or additional gear trains.
Solution Approach 2:
The carrier member serves multiple functions: it supports the planet gears, provides rotational movement for ratio adjustment, and can be locked to achieve direct drive. This multi-functionality eliminates the need for separate components, reducing overall device complexity while maintaining infinite speed ratio variability.
3Adaptability or versatility
If traditional CVT designs are used, then continuous speed ratio adjustment is achieved, but efficiency is reduced due to friction and elastohydrodynamic losses
Solution Approach 1:
The patent replaces friction-based and elastohydrodynamic torque transfer mechanisms with direct mechanical engagement of planetary gears. The gear teeth provide positive engagement that eliminates sliding friction and fluid-based torque transfer losses, significantly improving efficiency while maintaining continuous ratio adjustment capability.
4Device complexity
If a planetary gear-based IVT is used to reduce complexity, then the transmission structure is simplified, but manufacturing precision requirements increase for the gear components
Solution Approach 1:
The transmission is divided into multiple planetary gear sets with standardized components. By segmenting the system into modular units with identical or similar gear components, the patent enables use of standard manufacturing processes and interchangeable parts, reducing the impact of precision requirements on overall complexity.
Data Source
AI summary
Inventive embodiments are directed to components, subassemblies, systems, and/or methods for infinitely variable transmissions (IVT). In one embodiment, a control system is adapted to facilitate a change in the ratio of an IVT. In another embodiment, a control system includes a carrier member configured to have a number of radially offset slots. Various inventive carrier members and carrier drivers can be used to facilitate shifting the ratio of an IVT. In some embodiments, the traction planet assemblies include planet axles configured to cooperate with the carrier members. In one embodiment, the carrier member is configured to rotate and apply a skew condition to each of the planet axles. In some embodiments, a carrier member is operably coupled to a carrier driver. In some embodiments, the carrier member is configured to couple to a source of rotational power. Among other things, shift control interfaces for an IVT are disclosed.