Vertical Roller Mill Axis Deviation and Bearing Maintenance

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Solution Overview

Problem

Enlarged vertical roller mills face axis deviation issues during rotation and difficulties in performing maintenance and replacement of the thrust bearing mechanism due to its separation from the reduction gear, making maintenance more challenging.

Innovation Solution

A vertical roller mill design featuring a reduction gear below the rotary table, a vertical transmission shaft, an output flange with a radial bearing mechanism, and a working opening for easy access to the thrust bearing mechanism, allowing for axis deviation prevention and maintenance without issues, even when the mill is enlarged.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the rotary table and reduction gear are largely separated in the vertical direction to enlarge the mill, then the mill size and throughput are increased, but axis deviation of the rotary table upon rotation becomes larger

Engineering Contradiction:
Improvemill sizeVSAvoidaxis deviation
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

A vertical transmission shaft is introduced as an intermediary component to connect the reduction gear and rotary table when they are separated in the vertical direction. This transmission shaft transmits the driving force from the reduction gear to the rotary table, enabling the rotary table to rotate without direct contact with the reduction gear, thus allowing vertical separation while maintaining rotational function and preventing axis deviation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The drive system is segmented into separate functional components: the reduction gear, the vertical transmission shaft, and the rotary table. This segmentation allows each component to be optimized independently and positioned at appropriate vertical levels, enabling mill enlargement while maintaining precision through proper alignment and support mechanisms.

Inventive Principle:
Principle #1Segmentation

2Volume of moving object

If the thrust bearing mechanism is largely separated from the reduction gear to enlarge the mill, then the mill size is increased, but maintenance and replacement works on the thrust bearing mechanism become more difficult

Engineering Contradiction:
Improvemill sizeVSAvoidmaintenance accessibility
Core Design Contradiction:
Volume of moving objectVSEase of repair

Solution Approach 1:

The thrust bearing mechanism is segmented from the reduction gear and positioned on a separate support structure (column or pier). This segmentation allows the thrust bearing mechanism to be independently accessed, removed, and maintained without disassembling the reduction gear, significantly improving maintenance accessibility while enabling mill enlargement.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The thrust bearing mechanism is extracted from the integrated reduction gear structure and placed on a separate support structure. This extraction creates independent access paths to the thrust bearing mechanism through working openings in the rotary table and support structure, allowing maintenance personnel to reach and service the thrust bearing mechanism without interfering with the reduction gear or other mill components.

Inventive Principle:
Principle #2Taking out (Extraction)

3Volume of moving object

If the thrust bearing mechanism is separated from the reduction gear, then the mill can be enlarged, but the thrust bearing mechanism cannot be withdrawn up to a working area together with the reduction gear for maintenance

Engineering Contradiction:
Improvemill sizeVSAvoidmaintenance accessibility
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The thrust bearing mechanism is extracted from the reduction gear assembly and positioned on a separate support structure. This extraction enables independent access to the thrust bearing mechanism through dedicated working openings, allowing maintenance personnel to withdraw and service the thrust bearing mechanism separately from the reduction gear, thus improving maintenance accessibility while supporting mill enlargement.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The thrust bearing mechanism is positioned on a vertical support structure (column or pier) rather than being integrated horizontally with the reduction gear. This vertical arrangement creates separate access paths and working areas, allowing maintenance personnel to reach the thrust bearing mechanism from above through working openings in the rotary table and support structure, thereby improving accessibility for maintenance operations.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP3159060B1Vertical roller mill
Publication Date: 2021.05.12 KAWASAKI JUKOGYO KK
  • EP3159060B1 patent drawingFigure 1
  • EP3159060B1 patent drawingFigure 2
  • EP3159060B1 patent drawingFigure 3

AI summary

This vertical roller mill (1) is provided with a reduction gear (11) which is arranged below a rotary table (2), a vertical transmission shaft (13) for transmitting driving force from the reduction gear (11) to the rotary table (2), an output flange (23) to which an upper end of the vertical transmission shaft (13) is connected at the center portion thereof and which configures a bottom surface of the rotary table (2), a thrust bearing mechanism (27) for slidably supporting a peripheral portion of the output flange (23) from below, and a radial bearing mechanism (38) for restricting movement of the output flange (23) in the radial direction.