Integrated Motor Gear Drive for Mill Stability

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Solution Overview

Problem

Existing cement and coal mills with horizontal roller tables require complex and expensive bevel gear stages to transmit rotational movement, generating large radial and axial forces that complicate the mill construction and require separate motor support, leading to increased space and maintenance needs.

Innovation Solution

A heavy-duty drive arrangement with an integrated electric motor and gear assembly within a housing, eliminating the need for separate motor support and allowing for a compact, bevel gear-free design that reduces space requirements and enhances stability by supporting both the motor and gear on the housing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If bevel gear stages are used to transmit rotational movement in horizontal roller table mills, then the rotational movement can be transmitted from horizontal to vertical axis, but the manufacturing cost increases significantly and large radial and axial forces are generated in the bearings

Engineering Contradiction:
Improvemanufacturing costVSAvoidradial and axial forces in bearings
Core Design Contradiction:
Ease of manufactureVSForce

Solution Approach 1:

The patent extracts and eliminates the bevel gear stage from the drive arrangement, replacing it with a direct vertical motor drive. This removes the source of large radial and axial forces while maintaining the functional requirement of transmitting rotational movement from horizontal to vertical axis through the planetary gear arrangement.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent substitutes the complex bevel gear mechanical system with a simplified vertical motor direct drive system. The motor's vertical axis directly drives the planetary gear, eliminating the need for bevel gears and their associated bearing forces while achieving the same axis transformation function.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If the motor is arranged separately from the gearbox, then the motor can be positioned next to the gearbox for drive transmission, but the mill construction becomes more complex requiring separate motor support on foundation

Engineering Contradiction:
Improvedrive transmission arrangementVSAvoidmill construction complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent merges the motor and gearbox into a single integrated drive unit. The motor is positioned directly above the planetary gear with vertical alignment, combining what were previously separate components into one compact assembly that requires a single foundation support point, thereby simplifying the overall mill construction.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the spatial arrangement from horizontal side-by-side positioning to vertical stacking. The motor is arranged vertically above the gearbox rather than horizontally next to it, utilizing the vertical dimension to achieve compact integration and simplify support structure requirements.

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

3Power

If bevel gear stages are used in drive arrangements, then rotational movement transmission is achieved, but the space requirement increases and maintenance needs are increased

Engineering Contradiction:
Improverotational movement transmissionVSAvoidspace requirement
Core Design Contradiction:
PowerVSArea of stationary object

Solution Approach 1:

The patent extracts the bevel gear stage from the drive arrangement, eliminating it entirely. This removal reduces the occupied space while maintaining the power transmission function through the simplified vertical motor to planetary gear configuration, thereby decreasing both space requirements and maintenance needs.

Inventive Principle:
Principle #2Taking out (Extraction)

4Length of stationary object

If the motor is sunk into the foundation, then the height above the foundation can be saved, but the motor requires separate support structure and the large vertical forces must be dissipated laterally around the motor

Engineering Contradiction:
Improveheight above foundationVSAvoidsupport structure complexity
Core Design Contradiction:
Length of stationary objectVSDevice complexity

Solution Approach 1:

The patent merges the motor support function into the housing structure itself. The housing serves as both the motor enclosure and the support structure that transmits vertical forces directly to the foundation, eliminating the need for separate support structures and lateral force dissipation paths.

Inventive Principle:
Principle #5Merging (Combining)

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 provides a more stable, compact, and low-maintenance drive arrangement that reduces the complexity and cost associated with bevel gear stages, while allowing for reduced space requirements and improved overall stability of the mill.

Implementation Method 1

an electric motor (5) arranged below the gear arrangement (4)

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a gear arrangement (4) in which a planetary gear (4a) is used

Methodology Applied
Scientific EffectMechanical advantage: Mechanical Advantage

Data Source

PatentEP2323771B2Heavy-duty drive arrangement and mill driven by the same
Publication Date: 2016.12.14 F L SMIDTH & CO AS
  • EP2323771B2 patent drawingFigure 1
  • EP2323771B2 patent drawingFigure 2~3
  • EP2323771B2 patent drawingFigure 4~5

AI summary

A heavy-duty drive arrangement for a mill having a grinding bowl ratable about a vertical axis comprises a housing, an electric motor, and a gearing arrangement disposed in the housing and supported on the housing. The grinding bowl can be driven by means of the electric motor via the gearing arrangement. The electric motor is disposed below the gearing arrangement. The electric motor is integrated in the housing. Advantageously, the electric motor is supported on the housing particularly on a bottom element of the housing. The rotor can be connected directly, or via a coupling integrated in the rotor, to a gear of the gearing arrangement. The mill may be, for example, a roller bowl mill.