Fluid-Coupling CVT Layout for Uninterrupted Gear Shifts

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Solution Overview

Problem

Conventional continuously variable speed transmissions (CVTs) are not sturdy and are excessively loud due to their reliance on large belts or metal mesh, leading to inefficiencies and discomfort.

Innovation Solution

A CVT design utilizing multiple fluid couplings with adjustable impellers and turbines, controlled by a module to vary the distance between them, providing continuous variable ratios through hydraulic fluid instead of friction or belt drives, resulting in a more durable and quieter transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If large belts or metal mesh are used in CVT, then the transmission can achieve continuous variable ratios, but the structure becomes less sturdy and generates excessive noise

Engineering Contradiction:

Improvecontinuous variable ratiosVSAvoidsturdiness

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent replaces the traditional mechanical belt or metal mesh system with a fluid coupling system using hydraulic fluid. The fluid couplings transfer rotational force between impellers and turbines without direct mechanical contact, eliminating the noise and structural weaknesses associated with belt-driven CVTs while maintaining continuous variable ratio capability through adjustable impeller-turbine spacing

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs hydraulic fluid within multiple fluid couplings to transmit power from the engine to the drive train. By using hydraulic principles where the impeller moves fluid to rotate the turbine, the system achieves smooth continuous variable transmission ratios without the mechanical wear and noise inherent in belt-based systems, thereby improving sturdiness and reducing noise

Inventive Principle:

Principle #29Pneumatics and hydraulics

2Device complexity

If fixed position impellers and turbines are used in fluid couplings, then the structure is simpler, but the transmission cannot achieve continuously variable ratios

Engineering Contradiction:

Improvefixed position structureVSAvoidcontinuously variable ratios

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent transforms the static fixed-position impeller and turbine structure into a dynamic system where the spacing between impeller and turbine can be continuously adjusted. This dynamic adjustment capability allows the fluid coupling to vary the torque multiplication ratio continuously, enabling CVT functionality while maintaining the simplicity of the fluid coupling mechanism itself

Inventive Principle:

Principle #15Dynamics

3Productivity

If conventional gear shifts are used, then the transmission provides discrete ratios, but the gear changes cause pauses and reduce smoothness

Engineering Contradiction:

Improvediscrete gear ratiosVSAvoidsmoothness of transitions

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

The patent implements continuous adjustment of the impeller-turbine spacing within the fluid couplings, allowing the transmission ratio to change seamlessly without discrete steps or pauses. This continuous action eliminates the interruptions inherent in conventional gear shifting, providing smooth transitions while maintaining the ability to provide various transmission ratios through progressive spacing adjustment

Inventive Principle:

Principle #20Continuity of useful action

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 design achieves a steady output with gradual RPM changes without gear pauses, enhancing durability and reducing noise, offering smoother transitions and improved engine efficiency by eliminating heat generation and torque loss.

Implementation Method 1

The first impeller moves the hydraulic fluid to rotate the first turbine. The second impeller moves the hydraulic fluid to rotate the second turbine.

Methodology Applied

Scientific EffectHydraulic fluid coupling: Hydraulic Press

Implementation Method 2

fluid couplings with variable input from the couplings that provides a steady output to the drive train thus gradually varying output revolutions per minute (rpm)

Methodology Applied

Scientific EffectFluid dynamics: Hydraulic Press

Data Source

PatentUS11193570B2Continuous variable speed transmission using variable coupling arrangement

Publication Date: 2021.12.07 JOHNSON DAVID

AI summary

The variable speed transmission uses multiple fluid couplings to provide a sturdy, durable variable output ratio transmission by using hydraulic fluid to vary the output. Each fluid coupling has an independent output shaft driven by the respective fluid coupling turbine. Output shafts drive alternate gears (i.e., first and third at a first fluid coupling and second and fourth at a second fluid coupling). This configuration alternates gear shifts between the fluid couplings allowing the next gear up or down to be engaged before disengaging the current gear, for uninterrupted gear changes in both up and down shifting. A fifth gear would be driven by a gear connected to the fluid coupling input shafts. Gears could be engaged with hydraulic clutches or syncromesh gears. This combined with variable slip fluid couplings allows for better torque and control.