Planetary Friction Gear Transmission Axial Loading

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The existing planetary friction gear continuously variable transmission faces inefficiencies in torque loading due to insufficient pressing force at the contact point between the tapered roller and the transmission ring, obstructed by friction forces and accuracy issues at contact points.

Innovation Solution

The design includes a hollow cone-like carrier with a trapezoid cross-section, notched input and output support sections, and a loading mechanism with a rolling body that presses the ring roller and output shaft axially when a torque differential occurs, utilizing a tapered groove and cam mechanism to enhance pressing force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a loading mechanism with a rolling body is installed in the circular groove between the ring roller and the output shaft, then torque loading is enabled when a torque differential arises, but sufficient pressing force at the contact point between the tapered roller and the transmission ring cannot be obtained due to friction forces and accuracy issues at contact portions

Engineering Contradiction:
Improvepressing force at contact pointVSAvoidtorque loading efficiency
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

A cam mechanism is introduced as an intermediary element between the loading mechanism and the tapered roller. The cam mechanism converts the radial movement of the rolling body into axial pressing force, amplifying the effect and ensuring sufficient pressing force is applied to the contact point between the tapered roller and transmission ring, thereby resolving the insufficiency of direct pressing force transmission

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The design changes the geometric parameters of the cam mechanism and the positioning of the rolling body to optimize the force transmission path. By adjusting the cam profile and the groove geometry, the system transforms small radial displacements into significant axial pressing forces, overcoming the limitations imposed by friction and manufacturing accuracy at the contact portions

Inventive Principle:
Principle #35Parameter changes

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 configuration effectively improves torque loading efficiency by producing a sufficient pressing force at the contact point, reducing load on bearings and enhancing the conversion of input torque into a greater contact surface pressing force.

Implementation Method 1

the movement of the tapered roller in the axial direction is obstructed by an effect caused by a friction force or accuracy at each contact portion

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the rolling body presses the ring roller and the output shaft in the axial direction to carry out torque loading

Methodology Applied
Scientific EffectNormal force: Force

Implementation Method 3

enhancing the conversion of input torque into a greater contact surface pressing force

Methodology Applied
Scientific EffectMechanical advantage: Mechanical Advantage

Data Source

PatentEP2706266B1Planetary friction gear continuously variable transmission
Publication Date: 2019.09.11 ISUZU MOTORS LTD
  • EP2706266B1 patent drawingFigure 1
  • EP2706266B1 patent drawingFigure 2~3
  • EP2706266B1 patent drawingFigure 4~5(b)

AI summary

The present invention relates to a planetary friction gear continuously variable transmission and effectively improves the efficiency of torque loading. The present invention is provided with: an input shaft 12; a carrier 13; a planetary friction gear 16 having a tapered roller 16b and the like at an inclined rotating shaft 16d; an input-side support section 14 which is formed by notching a portion of the outer periphery of a carrier bottom section 13a and rotatably supports the input side of the rotating shaft 16d; a sun roller 17 provided on the same line as the input shaft 12; a ring roller 19 which is rotated by contacting a roller 16c of the planetary friction gear 16; an output shaft 20 provided spaced from the ring roller 19; a loading section 22 having a rolling body which presses the ring roller 19 and the output shaft 20 in the axial direction when a torque differential arises; and a transmission ring 21 which contacts the tapered roller 16b and allows the planetary friction gear 16 to spin.