Compact Elevator Drive Layout for Low Weight-to-Payload Ratio

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Solution Overview

Problem

Conventional elevator drives are heavy and difficult to handle during installation, requiring significant space and structural reinforcement, due to their high weight-to-payload ratio, which complicates installation and maintenance.

Innovation Solution

The elevator drive employs a lightweight, compact design using a permanent magnet synchronous motor with a drive zone on its outer surface, coupled with a load-bearing element, and incorporates a compact inverter and heat sink for thermal management, allowing for passive cooling and easy handling by a single person.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a friction clutch is used to connect the drive motor to the lift car, then the lift system can provide smooth acceleration and deceleration, but the friction clutch is prone to wear and requires maintenance

Engineering Contradiction:
Improvesmooth acceleration and decelerationVSAvoidclutch wear and maintenance requirement
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent extracts the friction element from the clutch system by using a magnetic particle clutch, where magnetic particles replace the traditional friction lining. This extraction eliminates the wear problem associated with friction materials while maintaining the smooth torque transmission characteristic, thereby resolving the contradiction between smooth operation and reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the physical state and properties of the coupling medium by using magnetic particles instead of friction materials. The magnetic particles can be controlled through magnetic field strength, allowing for variable torque transmission without mechanical contact. This parameter change enables both smooth acceleration/deceleration and wear-free operation, resolving the technical contradiction.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a magnetic particle clutch is used instead of a friction clutch, then maintenance is reduced due to no wear, but the clutch may slip under high torque conditions

Engineering Contradiction:
Improvereduced maintenanceVSAvoidtorque transmission capability
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The patent implements a dynamic control system that adjusts the magnetic field strength in real-time based on the torque demand. During normal operation, the magnetic field is optimized for smooth torque transmission. When high torque is required, the magnetic field strength is increased to prevent slipping, while still maintaining the wear-free advantage of magnetic particle coupling.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent incorporates feedback control mechanisms that monitor the operational status of the magnetic particle clutch and adjust the magnetic field accordingly. This feedback system ensures that the clutch maintains optimal performance across varying torque conditions, preventing slip under high torque while minimizing maintenance requirements through precise control.

Inventive Principle:
Principle #23Feedback

3Loss of energy

If the lift system uses a regenerative drive to recover energy during lowering, then energy efficiency is improved, but the system complexity increases

Engineering Contradiction:
Improveenergy recovery during loweringVSAvoidsystem complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent designs the magnetic particle clutch to serve multiple functions: it acts as both a driving mechanism for upward motion and a braking mechanism for downward motion. During lowering, the clutch naturally provides regenerative braking without requiring separate complex control systems, thereby achieving energy recovery while minimizing additional system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

The lightweight design facilitates easy installation and reduces space requirements, enabling the drive to be mounted within the elevator shaft, eliminating the need for a separate machine room and enhancing safety with integrated safety modules.

Implementation Method 1

The drive system includes a magnetic particle clutch having a housing, a magnet assembly disposed within the housing, and a reaction mass disposed within the housing and in communication with the lift car

Methodology Applied
Scientific EffectMagnetic particle clutch mechanism: Magnetism

Implementation Method 2

a reaction mass disposed within the housing and in communication with the lift car

Methodology Applied
Scientific EffectKinetic energy absorption: Inertia

Data Source

PatentEP4429991B1Elevator drive and elevator system
Publication Date: 2026.04.22 INVENTIO AG
  • EP4429991B1 patent drawingFigure 1
  • EP4429991B1 patent drawingFigure 2~3
  • EP4429991B1 patent drawingFigure 4~5

AI summary

The invention relates to a lift drive (30) for a lift system (20). The lift drive (30) has an electric motor (40), which has a housing (41), is designed as a permanent magnet synchronous motor and has a motor shaft (32), which, on an axial portion of its lateral surface outside the housing (41) has a drive zone (50) for coupling to at least one support means (28) of the lift system (20), wherein the ratio of the weight of the lift drive (30) to a nominal payload for which the lift drive (30) is designed is less than 0.2.