Planetary Gear Thrust Collar Fixing Mechanism

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Solution Overview

Problem

The existing structures for fixing thrust collars in planetary gear trains are inadequate, leading to performance deterioration and surface scratches, and are complex and costly, especially in high-load applications like wind turbine generators.

Innovation Solution

A simplified attachment mechanism for thrust collars using pins with adjustable lengths and internal/external threads, coupled with a drop-off prevention mechanism such as snap rings or elastic sleeves, ensures secure fixation without compromising the sliding surface area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If bolts are inserted from the sliding surface to fix the thrust collar, then the thrust collar can be securely fixed, but holes are formed on the sliding surface which reduce the sliding surface area and may cause scratches, deteriorating thrust bearing performance

Engineering Contradiction:

Improvefixing stability of thrust collarVSAvoidsliding surface area

Core Design Contradiction:

Stability of the object's compositionVSArea of stationary object

Solution Approach 1:

The fixing function is segmented from the sliding surface by using a separate fixing structure (protrusions on carrier, grooves on thrust collar) that operates independently from the sliding contact area, allowing secure fixation without compromising the sliding surface integrity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The harmful element (holes for bolts) is extracted from the sliding surface by implementing a different fixing mechanism that does not require penetrating the sliding surface, thereby preserving the complete sliding surface area and preventing scratches

Inventive Principle:

Principle #2Taking out (Extraction)

2Stability of the object's composition

If a complicated fixing structure with openings through the carrier and locking clicks is used, then the thrust collar can be fixed, but the structure becomes complex which reduces productivity and increases production cost

Engineering Contradiction:

Improvefixing stability of thrust collarVSAvoidstructure complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The complex fixing mechanism (openings through carrier, locking clicks) is replaced by a simplified protrusion-groove interlocking structure that achieves the same fixing stability with significantly reduced structural complexity, improving manufacturability and productivity

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of inserting locking elements into openings as in conventional designs, the invention inverts the approach by having the carrier provide protrusions that fit into grooves on the thrust collar, simplifying the overall structure while maintaining fixing reliability

Inventive Principle:

Principle #13The other way round (Inversion)

3Device complexity

If rolling bearings are used in the planetary gear train, then the structure is simple, but the lifetime is reduced when large loads are applied

Engineering Contradiction:

Improvebearing structure simplicityVSAvoidbearing lifetime

Core Design Contradiction:

Device complexityVSDuration of action of stationary object

Solution Approach 1:

The bearing type is changed from rolling contact (rolling bearings) to sliding contact (sliding bearings), fundamentally altering the contact parameter between bearing surfaces. This parameter change enables the bearing to sustain large loads with significantly extended lifetime while maintaining structural simplicity through the integrated sliding bearing design

Inventive Principle:

Principle #35Parameter changes

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 effectively prevents performance deterioration and surface damage while maintaining a simple and cost-effective structure, ensuring reliable operation under high loads.

Implementation Method 1

The sliding bearing can sustain the large load, since receiving the load with fluid oil film pressure.

Methodology Applied

Scientific EffectFluid oil film pressure: Lubrication

Data Source

PatentUS8932177B2Planetary gear train with thrust collar used as thrust bearing of planetary gear and wind turbine generator incorporating the same

Publication Date: 2015.01.13 MITSUBISHI HEAVY IND LTD

AI summary

A planetary gear train is provided with: a carrier; a planetary gear; a planetary pin inserted into an insert hole provided through the planetary gear and coupled to the carrier to rotatably support the planetary gear; a thrust collar attached to a surface opposed to the planetary gear of the carrier so as to surround the planetary pin; and a pin for coupling the thrust collar to the carrier. The thrust collar has a first surface opposed to the carrier and a second surface opposed to the planetary gear, and has a first pin hole provided on the first surface so as not to reach the second surface. The carrier has a second pin hole on a surface opposed to the planetary gear. The thrust collar is attached to the carrier by inserting the pin into the first pin hole of the thrust collar and into the second pin hole of the carrier.