Segmented Helical Gear PE-IVT for Continuous High-Torque Shifting

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Solution Overview

Problem

Conventional continuously variable transmissions (CVTs) face challenges in providing sufficient torque and efficiency for large vehicles and electric vehicles, leading to issues like slippage, wear, and limited range, due to frictional losses and the Non-Integer-Tooth Problem (NITP), which affects their durability and performance.

Innovation Solution

A positively-engaged infinitely-variable transmission (PE-IVT) system utilizing a gear assembly with helical gears and a swashplate that allows axial motion of gear segments, constrained by a mechanical linkage, enabling continuous gear ratio adjustment and overcoming the NITP by storing and distributing remainders through axial freedom and thread-aligners.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If friction-driven CVT is used to achieve continuous gear ratio adjustment, then smooth operation is improved, but torque capability and efficiency deteriorate due to slippage and frictional losses

Engineering Contradiction:

Improvesmooth operationVSAvoidtorque capability

Core Design Contradiction:

Ease of operationVSPower

Solution Approach 1:

The patent replaces the friction-based mechanical system with a positive engagement gear system. The gear assembly with axially movable gear segments engages teeth-to-teeth rather than relying on friction, eliminating slippage while maintaining continuous variability. This substitution resolves the contradiction by providing both smooth operation and high torque capability through direct mechanical engagement.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The gear assembly is divided into multiple gear segments that can move axially independently along the shaft. This segmentation allows continuous adjustment of the effective gear ratio by varying the axial position of segments, while each segment maintains positive engagement. The segmented structure enables smooth variability without sacrificing torque transmission capability.

Inventive Principle:

Principle #1Segmentation

2Ease of operation

If friction-driven CVT is used to achieve continuous gear ratio adjustment, then smooth operation is improved, but durability deteriorates due to wear

Engineering Contradiction:

Improvesmooth operationVSAvoiddurability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent replaces the friction-based mechanical system with a positive engagement gear system. By using tooth-to-tooth engagement instead of friction contact, the system eliminates the sliding wear that plagues conventional CVTs. This substitution resolves the contradiction by providing both smooth operation and enhanced durability through the wear-resistant nature of positive engagement gearing.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If conventional CVT is used to achieve continuous gear ratio adjustment, then smooth operation is improved, but efficiency deteriorates due to frictional losses

Engineering Contradiction:

Improvesmooth operationVSAvoidfrictional losses

Core Design Contradiction:

Ease of operationVSLoss of energy

Solution Approach 1:

The patent replaces the friction-based mechanical system with a positive engagement gear system. By eliminating friction contact between belt and pulley, the system removes the primary source of energy loss. This substitution resolves the contradiction by maintaining smooth operation through continuous axial movement of gear segments while dramatically reducing energy losses through efficient tooth engagement.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Adaptability or versatility

If gear ratio range is extended to overcome Non-Integer-Tooth Problem, then adaptability is improved, but device complexity increases

Engineering Contradiction:

Improvegear ratio rangeVSAvoidstructural complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The gear assembly is divided into multiple gear segments that can move axially independently along the shaft. This segmentation allows continuous adjustment of the effective gear ratio by varying the axial position of segments, enabling a wide gear ratio range without requiring complex mechanisms. The segmented structure provides adaptability while maintaining relatively simple construction.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The gear segments are designed to move dynamically along the shaft axis, allowing the effective number of engaged teeth to vary continuously. This dynamic adjustment capability enables the system to overcome the Non-Integer-Tooth Problem and achieve a broad gear ratio range without fixed discrete steps, maintaining adaptability while avoiding excessive complexity.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS11085511B1Positively-engaged infinitely-variable transmission

Publication Date: 2021.08.10 BRUSH ETHAN

AI summary

A positively-engaged infinitely-variable transmission (PE-IVT) system employs a gear assembly including a first helical gear and a second helical gear meshed with the first helical gear. The first helical gear is divided into a plurality of gear segments that can individually move axially along a spline shaft. The PE-IVT system further includes a swashplate configured to constrain the axial motion of the plurality of gear segments. In some embodiments, the system further includes one or more thread-aligners configured to axially align a gear segment with one or more additional gear segments. In some embodiments, the second helical gear is also divided into a plurality of gear segments.