Cycloidal Reducer Suspension for Self-Adjusting Backlash

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Solution Overview

Problem

Cycloidal gear reducers used in power steering systems face issues with backlash and operational noise due to radial clearance between cycloidal disks and rims, leading to manufacturing complexity, high costs, and reduced service life.

Innovation Solution

A cycloidal gear reducer with a suspension device that elastically biases the cycloidal toothing of the disk and the rim against each other, providing automatic adjustment of backlash and accommodating manufacturing and assembly tolerances, as well as wear, thereby simplifying assembly and improving operational smoothness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an eccentric setting mechanism is used to adjust backlash, then backlash adjustment is achieved, but device complexity and manufacturing cost increase significantly

Engineering Contradiction:

Improvebacklash adjustmentVSAvoidnumber of parts

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the backlash adjustment function from a complex multi-component eccentric setting mechanism and implements it through a simplified structure using only two cylindrical elements with different diameters, eliminating rollers, axes, eccentric nuts, and blocking screws

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using a complex mechanism to actively adjust backlash, the patent inverts the approach by using a simple two-element system where the elements naturally self-adjust through their geometric difference, reversing the traditional active adjustment paradigm

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

If an eccentric setting mechanism with many parts is used, then backlash can be adjusted, but manufacturing and assembly time increase

Engineering Contradiction:

Improvebacklash adjustmentVSAvoidassembly time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent segments the backlash adjustment function into two distinct cylindrical elements with different diameters, allowing independent positioning and adjustment without requiring assembly of multiple interconnected components like rollers and axes

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The two cylindrical elements automatically self-adjust the backlash through their geometric difference, eliminating the need for complex blocking screws and manual setting procedures, thereby reducing assembly and adjustment time

Inventive Principle:

Principle #25Self-service

3Reliability

If a complex setting mechanism is used, then backlash adjustment is possible, but manufacturing cost increases

Engineering Contradiction:

Improvebacklash adjustmentVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent extracts the essential backlash adjustment function from a complex mechanism and implements it with two simple cylindrical elements, eliminating expensive components such as precision rollers, axes, eccentric nuts, and blocking screws

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces expensive, complex precision components with simple, inexpensive cylindrical elements that can be easily manufactured and replaced if needed, significantly reducing manufacturing cost

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

4Device complexity

If traditional cycloidal reducer design is used, then structure is simple, but backlash causes shocks and operating noises

Engineering Contradiction:

Improvestructural simplicityVSAvoidoperating noises

Core Design Contradiction:

Device complexityVSObject-generated harmful factors

Solution Approach 1:

The patent introduces two cylindrical elements with different diameters as intermediary components between the cycloidal disk and rim, which act as mediators to automatically adjust and eliminate backlash, thereby preventing shocks and operating noises while maintaining structural simplicity

Inventive Principle:

Principle #24Intermediary (Mediator)

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 results in a more reliable, cost-effective, and long-lasting cycloidal gear reducer with reduced backlash and improved operational comfort, particularly in power steering systems, by automatically adjusting for radial variations and ensuring seamless meshing.

Implementation Method 1

a suspension device which is arranged to elastically bias the cycloidal toothing of the cycloidal disk and the receiving toothing of the rim against each other

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS10926792B2Cycloidal reducer with backlash self-adjustment and power steering system with such a reducer

Publication Date: 2021.02.23 JTEKT EUROPE SAS

AI summary

A cycloidal gear pair reducer including an input shaft, mounted in a reducer casing such that it rotates about an axis referred to as “main axis”, an eccentric member carried by the input shaft and rotated by the latter, at least one cycloidal disc rotatably mounted on the eccentric member and having a cycloidal toothing, at least one ring gear provided with a receiving toothing with which the cycloidal toothing of the cycloidal disc meshes, and an output shaft; wherein the reducer comprises a suspension device arranged to return elastically the cycloidal toothing of the cycloidal disc and the receiving toothing of the ring gear towards one another such that the meshing backlash between the cycloidal disc and the ring gear is self-adjusted along at least one radial component relative to the main axis.