Gear Bearing Layout for Load Line Alignment and Longer Life

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Solution Overview

Problem

The life of gear devices is influenced by the relationship between load action lines and their components, and existing designs fail to optimize this relationship for long-life performance.

Innovation Solution

A gear device design where the distance between intersections of load action lines of main bearings is set within a specific range, ensuring appropriate positioning to enhance robustness and performance, with load action lines passing through the outer cylinder and flange portion consecutively, and the intersection positioned in the flange portion to prevent deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If the load action line intersects the rotation axis at arbitrary positions, then the gear device structure is simple, but the gear device life is reduced due to improper load distribution

Engineering Contradiction:
Improvegear device lifeVSAvoidbearing positioning complexity
Core Design Contradiction:
Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by optimizing the positional parameters of the load action lines relative to the rotation axis. Specifically, it sets the distance between the first intersection and second intersection (IID) within a specific range (0.1-0.3 times the distance between the two bearings), and positions the intersection of load action lines within the flange portion. These parameter optimizations improve load distribution and gear device life without fundamentally changing the structural complexity.

Inventive Principle:
Principle #35Parameter changes

2Strength

If the load action lines are positioned without specific constraints, then the manufacturing process is simple, but the robustness against external forces is insufficient

Engineering Contradiction:
Improverobustness against external forcesVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent establishes specific parameter ranges for load action line positioning: the distance IID between intersections should be 0.1-0.3 times the bearing distance BBD, and the intersection of load action lines should be located within the flange portion at a distance BID of 0.05-0.2 times BBD from the rotation axis. These parameter specifications enhance robustness while maintaining manufacturing feasibility through clear design guidelines.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses the flange portion structure as a reference framework for positioning the load action line intersection. By designing the bearing arrangement to align with the existing flange geometry, the patent leverages the flange's structural properties to enhance robustness without requiring additional complex manufacturing processes.

Inventive Principle:
Principle #26Copying

3Stability of the object's composition

If the intersection of load action lines is positioned outside the flange portion, then the structural design is simpler, but deformation occurs under load

Engineering Contradiction:
Improvestructural stabilityVSAvoidpositioning precision requirement
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent specifies that the intersection of load action lines should be positioned within the flange portion, at a distance BID of 0.05-0.2 times the bearing distance BBD from the rotation axis. This parameter constraint ensures the intersection falls within the structurally stable flange region, preventing deformation while maintaining reasonable positioning precision requirements.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3865730B1Gear device
Publication Date: 2024.03.27 NABTESCO CORP
  • EP3865730B1 patent drawingFigure 1
  • EP3865730B1 patent drawingFigure 2
  • EP3865730B1 patent drawing

AI summary

The present application discloses a gear device provided with: an outer cylinder; an internal member at least partially housed in the outer cylinder and configured to rotate relative to the outer cylinder about a predetermined rotation axis; a first main bearing fitted into an annular space formed between the outer cylinder and the internal member; and a second main bearing fitted into the annular space and configured to define the rotation axis in cooperation with the first main bearing. A distance between a first intersection where a load action line of the first main bearing intersects with the rotation axis and a second intersection where a load action line of the second main bearing intersects with the rotation axis is set to fall within a range expressed by a predetermined inequality expression.