Gear Transmission Part Reduction via Extracted Bearing

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional gear transmissions in industrial robots and machine tools have a high number of parts, leading to increased costs and complexity, particularly due to the use of tapered roller bearings for supporting the crank member and carrier.

Innovation Solution

The gear transmission reduces the number of parts by omitting inner races and using only rolling elements and outer races between the crank member and carrier, and between the eccentric rotation member and the external gear, allowing for a more compact design and lower production costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional tapered roller bearings are used to support the crank member and carrier, then the gear transmission achieves reliable rotational support, but the number of parts increases and manufacturing cost increases

Engineering Contradiction:
Improverotational support reliabilityVSAvoidnumber of parts
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts and removes the inner race from the tapered roller bearing assembly, retaining only the essential components (outer race and rolling elements) needed to achieve the supporting function. This reduces the number of parts while maintaining the core rotational support capability between the crank member and carrier, and between the carrier and internal gear.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces expensive conventional tapered roller bearings with a simplified bearing structure that uses fewer components. By omitting the inner race and using only outer races and rolling elements, the design achieves cost reduction while maintaining adequate support functionality for the application.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Reliability

If conventional tapered roller bearings are used to support the crank member and carrier, then the gear transmission achieves stable rotational support, but manufacturing cost increases

Engineering Contradiction:
Improverotational support stabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention extracts and removes the inner race from the tapered roller bearing assembly, retaining only the essential components (outer race and rolling elements) needed to achieve the supporting function. This reduces the number of parts while maintaining the core rotational support capability between the crank member and carrier, and between the carrier and internal gear.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces expensive conventional tapered roller bearings with a simplified bearing structure that uses fewer components. By omitting the inner race and using only outer races and rolling elements, the design achieves cost reduction while maintaining adequate support functionality for the application.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Reliability

If inner races are included in the bearing assembly, then the crank member is properly supported, but the space for wiring or piping is reduced

Engineering Contradiction:
Improvecrank member supportVSAvoidspace for wiring or piping
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The invention extracts and removes the inner race from the tapered roller bearing assembly, retaining only the essential components (outer race and rolling elements) needed to achieve the supporting function. This reduces the number of parts while maintaining the core rotational support capability between the crank member and carrier, and between the carrier and internal gear.

Inventive Principle:
Principle #2Taking out (Extraction)

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 results in a lower-cost gear transmission with reduced part count, maintaining performance while allowing for increased space for wiring or piping and improving torsional rigidity, thus achieving a more compact and cost-effective solution.

Implementation Method 1

only rolling elements and outer races between the crank member and carrier, and between the eccentric rotation member and the external gear

Methodology Applied
Scientific EffectRolling friction: Roller

Implementation Method 2

The eccentric rotation member has an axis line of rotation at a position offset from an axis line of the shaft and is fitted in the center through hole of the external gear

Methodology Applied
Scientific EffectEccentric rotation: Eccentric

Data Source

PatentEP2119941B1Gear device
Publication Date: 2011.10.12 NABTESCO CORP
  • EP2119941B1 patent drawingFigure 1
  • EP2119941B1 patent drawingFigure 2
  • EP2119941B1 patent drawingFigure 3

AI summary

The number of parts constituting a gear transmission is reduced, and a low cost gear transmission is presented. External gears 18X and 18Y have a number of teeth differing from a number of teeth of an internal gear 48, and are maintained in a meshing state with the internal gear 48. A center through hole and offset through holes 19X and 19Y are formed in the external gears 18X and 18Y. Column-shaped members 46 of a carrier pass through the offset through holes 19X and 19Y of the external gears 18X and 18Y. A pair of supporting members 42X and 42Y of the carrier supports each end of the column-shaped members 46. A pair of grooves is formed on a surface of a shaft of a crank member 14 at positions between which eccentric rotation members are interleaved. Rolling elements 8X and 8Y and outer races 6X and 6Y are arranged between each of the supporting members 42X and 42Y and the grooves. The shaft of the crank member 14 is supported so as to be capable of rotating with respect to the carrier and incapable of moving in its axial direction.