Torsion Spring CVT Coupling for Low-Wear Rapid Ratio Shifts

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Solution Overview

Problem

Existing continuously variable transmissions face challenges with high frictional losses, wear, and limited rapid ratio changes due to punctiform friction connections, which result in high surface loads and restricted speed in altering transmission ratios.

Innovation Solution

A mechatronic transmission system utilizing a clutch wheel and torsion spring, with non-rotatable, non-positive couplings that only engage when components have the same rotational speed, minimizing friction losses and enabling rapid, stepless adjustment of transmission ratios through controlled coupling and decoupling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If punctiform friction connections are used in continuously variable transmissions, then torque transmission is achieved, but frictional losses and wear increase due to high surface loads

Engineering Contradiction:
Improvefrictional lossesVSAvoidsurface loads
Core Design Contradiction:
Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the traditional mechanical friction-based torque transmission system with a magnetic coupling system. Magnetic particles are suspended in a fluid between two rotating elements, and when a magnetic field is applied, the particles align to transmit torque without direct mechanical contact. This substitution eliminates the punctiform friction connections that cause high surface loads and energy losses, while maintaining effective torque transmission capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Speed

If traditional friction-based couplings are used, then torque transmission is possible, but the speed of altering transmission ratios is limited

Engineering Contradiction:
Improvespeed of altering transmission ratiosVSAvoidratio change capability
Core Design Contradiction:
SpeedVSProductivity

Solution Approach 1:

The magnetic coupling system allows for dynamic and instantaneous adjustment of transmission ratios by controlling the magnetic field strength and distribution. Unlike mechanical friction couplings that require physical movement and contact to change ratios, the magnetic system can be adjusted electronically and immediately, enabling rapid ratio changes without mechanical wear or time delays.

Inventive Principle:
Principle #15Dynamics

3Reliability

If mechanical friction connections are used for torque transmission, then power transfer is achieved, but wear and reliability decrease

Engineering Contradiction:
Improvetransmission reliabilityVSAvoidwear
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces direct mechanical friction connections with a magnetic field-based torque transmission system. The magnetic particles in the fluid couple the two rotating elements through magnetic attraction rather than mechanical contact, eliminating the wear that occurs in traditional friction-based systems. This substitution significantly improves transmission reliability by removing the wear mechanism entirely.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 solution reduces frictional losses, minimizes wear, and allows for instantaneous and efficient adjustment of transmission ratios, enhancing the transmission's reliability and performance by avoiding high surface loads and enabling rapid changes in the transmission ratio.

Implementation Method 1

a clutch wheel (4) and a torsion spring (5), wherein the clutch wheel (4) is rotatably mounted on the same axis and can be connected to the output shaft (3) by the torsion spring (5)

Methodology Applied
Scientific EffectTorsion spring: Torsion Spring

Data Source

PatentEP3325846B1Transmission having a torsion spring and method for operating a transmission
Publication Date: 2021.04.14 WEILENMANN MARTIN
  • EP3325846B1 patent drawingFigure 1
  • EP3325846B1 patent drawingFigure 2~2e

AI summary

The invention relates to a mechatronic transmission (1) for transmitting a torque or power from the drive shaft (2) that can be supported axially on a shaft (A) to an output shaft (3), the rotational speeds of which can have an arbitrary and variable ratio (stepless transmission), comprising a coupling gear (4) and a torsion spring (5), wherein the coupling gear (4) is rotatably mounted on the same shaft (A) and can be connected to the output shaft (3) by the torsion spring (5), and comprising a first coupling means (7) for producing and cancelling a rotationally fixed, planar, force-fitting first coupling between the drive shaft (2) and the coupling gear (4). According to the invention, the transmission comprises a supporting device (6) which is rotatable having a fixed transmission ratio of 1:X relative to the output shaft (3), where X can be any real number between approximately -10 and 1, and a second coupling means (8) for producing and cancelling a rotationally fixed, force-fitting second coupling between the supporting device (6) and the coupling gear (4).