Toroidal CVT Roller Cooling Nozzle Layout for Heat Dissipation

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Solution Overview

Problem

Toroidal Continuously Variable Transmissions (CVTs) face challenges in effectively cooling rollers due to friction-generated heat, which can lead to premature degradation if not adequately addressed.

Innovation Solution

A cooling arrangement featuring nozzles that project cooling fluid onto the edge and opposite surfaces of rollers, increasing the contact surface area for efficient cooling, with hollow tubes and a non-rotating hub configuration ensuring consistent alignment regardless of roller angle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If cooling fluid is projected only onto the edge of the roller, then the nozzle structure is simple, but the cooling efficiency is insufficient due to limited contact surface area

Engineering Contradiction:
Improveroller temperatureVSAvoidcontact surface area
Core Design Contradiction:
TemperatureVSArea of stationary object

Solution Approach 1:

The cooling arrangement transitions from one-dimensional edge cooling to three-dimensional surface cooling by adding nozzles positioned at the top and bottom of the roller, projecting cooling fluid onto the entire roller surface including edges and opposite surfaces, thereby dramatically increasing the contact surface area for heat dissipation

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Temperature

If nozzles are positioned to cool all roller surfaces, then cooling efficiency is improved, but the device complexity increases due to additional nozzles and positioning requirements

Engineering Contradiction:
Improveroller temperatureVSAvoidnozzle arrangement complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The cooling system is segmented into multiple independent nozzles positioned at different locations (edge, top, bottom) around the roller, with each nozzle responsible for cooling a specific surface area, allowing for modular design and maintenance while achieving comprehensive coverage

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The nozzle arrangement is designed to accommodate dynamic roller angles through the toroidal CVT mechanism, with nozzles positioned to maintain effective cooling coverage regardless of the roller's rotational position or angle changes during operation

Inventive Principle:
Principle #15Dynamics

3Temperature

If cooling fluid flow rate is increased to improve cooling efficiency, then heat dissipation is enhanced, but energy consumption and fluid loss increase

Engineering Contradiction:
Improveroller temperatureVSAvoidcooling fluid energy
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

Cooling fluid is directed precisely to specific locations on the roller surface through strategically positioned nozzles, concentrating the cooling effect where heat generation is highest (edge and contact surfaces) rather than applying fluid uniformly, thereby maximizing cooling efficiency per unit of fluid consumed

Inventive Principle:
Principle #3Local quality

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 solution provides enhanced roller cooling efficiency, preventing premature degradation and ensuring reliable operation across varying transmission ratios by maintaining effective heat dissipation.

Implementation Method 1

a nozzle so configured and sized as to project cooling fluid onto the edge and onto the opposite surfaces of the roller

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

the friction present between the rollers and the disks generate heat in the rollers. To prevent premature degradation of the transmission, the rollers must be cooled

Methodology Applied
Scientific EffectHeat dissipation: Heat Sink

Data Source

PatentEP3390866B1Roller cooling arrangement for toroidal cvt
Publication Date: 2022.07.20 TRANSMISSION CVT CORP
  • EP3390866B1 patent drawingFigure 1
  • EP3390866B1 patent drawingFigure 2
  • EP3390866B1 patent drawingFigure 3

AI summary

A cooling arrangement to cool the rollers of a toroidal CVT is described herein. The cooling arrangement includes nozzles so configured and sized as to project cooling fluid onto the edge and onto the opposite top and bottom surfaces of the roller.