Eccentric Gear Hub Backlash Adjustment Mechanism

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Solution Overview

Problem

Existing methods for establishing a predetermined backlash between gears in gear transmissions, such as those involving idler gears, require complex alignment equipment and are difficult to fine-tune, especially due to arbitrary center of rotation positioning and the need for repeated adjustments.

Innovation Solution

The gear incorporates displacement means within the axial gear hub opening to translate the center of rotation from a zero-backlash position to a predetermined backlash position, using an eccentric gear hub opening and inner hub configuration, with markings and bolting mechanisms to facilitate easy alignment and maintain backlash during operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If elaborate alignment equipment is used to establish predetermined backlash, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:
Improvebacklash precisionVSAvoidalignment equipment complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent changes the geometric parameter of the gear hub opening by making it eccentric relative to the gear ring. This eccentricity creates a predetermined offset between the center of rotation of the gear ring and the center of the gear hub opening, thereby establishing a specific backlash value without requiring complex alignment equipment. The backlash is determined by the eccentric distance rather than by complex positioning mechanisms.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces asymmetry by positioning the gear hub opening eccentrically with respect to the gear ring. This asymmetric configuration ensures that the center of rotation of the gear ring does not coincide with the center of the gear hub opening, creating a predetermined backlash. The asymmetric design simplifies the assembly process by eliminating the need for complex alignment procedures.

Inventive Principle:
Principle #4Asymmetry

2Manufacturing precision

If repeated adjustment of eccentric bearing position is performed, then manufacturing precision is improved, but loss of time increases

Engineering Contradiction:
Improvebacklash precisionVSAvoidadjustment time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The eccentric gear hub opening is pre-configured during manufacturing with a specific eccentric distance that corresponds to the desired backlash value. This preliminary action eliminates the need for repeated adjustments during assembly, as the predetermined backlash is automatically achieved when the gear components are assembled in their normal positions.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The eccentric geometry of the gear hub opening automatically establishes the correct backlash without requiring operator intervention for adjustment. The design itself provides the necessary positioning function, eliminating the time-consuming process of repeated tightening and loosening of bolts to achieve optimal backlash.

Inventive Principle:
Principle #25Self-service

3Ease of manufacture

If arbitrary positioning of gear center of rotation is used, then ease of manufacture is improved, but manufacturing precision worsens

Engineering Contradiction:
Improvegear assembly easeVSAvoidbacklash consistency
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent employs asymmetric positioning of the gear hub opening relative to the gear ring, creating a fixed eccentric relationship. This asymmetric design provides both ease of manufacture (as components can be assembled without complex alignment) and manufacturing precision (as the eccentric distance predeterminedly establishes consistent backlash across all assembled gears).

Inventive Principle:
Principle #4Asymmetry

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 allows for easy and reliable establishment of a predetermined backlash, reducing the complexity of alignment and ensuring the backlash remains consistent during gear operation, even after assembly or repairs.

Implementation Method 1

the gear hub opening is eccentric with respect to the gear ring

Methodology Applied
Scientific EffectEccentric configuration: Eccentric

Data Source

PatentEP2886910B1Gear, gear train, engine, use thereof and method for mating such gear with at least one further gear with a predetermined backlash
Publication Date: 2020.04.01 VCST IND PROD
  • EP2886910B1 patent drawingFigure 1~3

AI summary

Gear (1), for example an idler gear (2), comprising a gear ring (3) rotationally mounted around a gear hub (4), the gear hub (4) comprising an axial gear hub opening (5), wherein the gear (1) comprises displacement means (6) in the gear hub opening (5), the displacement means (6) being provided for predeterminedly translating the centre of rotation of the gear ring (3) by moving the gear ring (3) and the gear hub (4) with respect to the centre of rotation of at least one further gear (7) from a first predetermined position in which the gear mates with the at least one further gear with substantially no backlash to a second predetermined position in which the gear mates with the at least one further gear with a predetermined backlash.