Elevator Stator Support Plates for Thermal Expansion

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Solution Overview

Problem

Traditional elevator machines are large, heavy, and subject to fatigue stresses due to internal rotor motors and stiff stator support structures, which reduce motor reliability and prevent space for bearings within the traction sheave envelope.

Innovation Solution

A stator assembly is coupled with support plates that allow radial and axial expansion over a range of temperatures, enabling the stator assembly to expand uniformly and reducing stress, while allowing bearings to be housed within the sheave envelope, thus reducing the machine's size and length.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a stiff stator support structure is used, then structural strength is improved, but thermal expansion stress increases and motor reliability decreases

Engineering Contradiction:

Improvestructural strengthVSAvoidmotor reliability

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The support structure transitions from a static rigid configuration to a dynamic system that adapts to thermal conditions. The stator assembly is designed to flex and expand radially and axially in response to temperature changes, with the support structure providing controlled compliance through flexible mounting arrangements that maintain structural integrity while accommodating dimensional changes.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the physical parameters of the support structure by introducing flexibility and compliance characteristics. The stator assembly's thermal expansion parameters are accommodated through design features that allow controlled movement and deformation, transforming the rigid parameter set into one that includes controlled flexibility and thermal adaptability.

Inventive Principle:

Principle #35Parameter changes

2Volume of moving object

If an internal rotor motor configuration is used, then machine compactness is improved, but the machine becomes long and heavy with high fatigue stresses

Engineering Contradiction:

Improvemachine compactnessVSAvoidmachine weight

Core Design Contradiction:

Volume of moving objectVSWeight of moving object

Solution Approach 1:

The invention repositions the motor from an internal rotor configuration to an external rotor arrangement located at the ends of the traction sheave. This dimensional reconfiguration allows the motor to drive the sheave through direct coupling while maintaining a compact overall footprint, distributing mass more effectively and reducing the long, heavy configuration associated with internal rotor designs.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Stability of the object's composition

If a stiff stator support structure is used, then structural stability is improved, but the machine size increases and bearings cannot be housed within the sheave envelope

Engineering Contradiction:

Improvestructural stabilityVSAvoidmachine size

Core Design Contradiction:

Stability of the object's compositionVSVolume of moving object

Solution Approach 1:

The support structure incorporates dynamic compliance that allows the stator assembly to expand and contract with temperature changes while maintaining stable operational alignment. This controlled flexibility enables a more compact machine configuration where bearings can be positioned within the sheave envelope, eliminating the need for extended rigid support structures.

Inventive Principle:

Principle #15Dynamics

4Strength

If the stator is constrained to prevent expansion, then structural integrity is maintained, but thermal stress increases and reduces operational life

Engineering Contradiction:

Improvestructural integrityVSAvoidoperational life

Core Design Contradiction:

StrengthVSDuration of action of stationary object

Solution Approach 1:

The invention converts the harmful effect of thermal expansion into a beneficial feature by designing the support structure to accommodate and utilize this expansion. Rather than restraining the stator and creating stress, the structure is configured to allow controlled radial and axial expansion, transforming what was previously a harmful constraint into a design feature that preserves structural integrity while extending operational life.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 design enhances motor reliability, extends operational life, and improves high-temperature operating efficiency by reducing stress and noise, while allowing a more compact machine configuration.

Implementation Method 1

configured to enable the stator assembly to expand radially and axially in a substantially uniform manner over a range of temperatures

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS10081518B2Elevator machine and stator support structure

Publication Date: 2018.09.25 OTIS ELEVATOR CO

AI summary

Embodiments are directed an elevator machine comprising: a stator assembly, and a plurality of support plates coupled to the stator assembly, wherein a respective at least one of the support plates is coupled on each end of the stator assembly and configured to enable the stator assembly to expand radially and axially in a substantially uniform manner over a range of temperatures.