Elevator Element Directional Roughness Wear

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Solution Overview

Problem

Elevator elements with uniform contact surface roughness lead to high wear and production costs, and insufficient roughness can negatively impact lateral guidance, especially with flat belts.

Innovation Solution

Elevator elements with different arithmetic mean roughness values in the circumferential and axial directions, ranging from 0.1 to 0.8 micrometers, are manufactured using techniques like turning or precision grinding, and optionally coated with chromium, to minimize wear and production costs while enhancing lateral guidance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the contact surface roughness is increased to reduce wear, then wear resistance improves, but production costs increase due to more complex manufacturing processes

Engineering Contradiction:
Improvewear resistanceVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies different roughness values in different directions on the contact surface. The circumferential direction has lower roughness (0.1-0.8 µm) to minimize wear during rotation, while the axial direction has higher roughness for improved lateral guidance. This directional differentiation allows optimization of wear resistance without requiring uniformly high roughness across the entire surface, thus reducing manufacturing complexity and cost compared to conventional uniform high-roughness surfaces.

Inventive Principle:
Principle #3Local quality

2Reliability

If the contact surface roughness is decreased to reduce wear, then wear resistance improves, but lateral guidance capability deteriorates

Engineering Contradiction:
Improvewear resistanceVSAvoidlateral guidance
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent implements directional roughness differentiation where the circumferential roughness is optimized for wear resistance (0.1-0.8 µm) while the axial roughness is increased to enhance lateral guidance of the suspension element. This allows the surface to simultaneously provide low wear during rotation and effective lateral positioning, resolving the contradiction between wear resistance and guidance capability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent creates an asymmetric roughness pattern on the contact surface by specifying different roughness values for different directions (circumferential vs. axial). This asymmetric surface structure enables the contact surface to perform different functions in different directions: smooth operation in the circumferential direction for wear reduction, and textured guidance in the axial direction for lateral positioning.

Inventive Principle:
Principle #4Asymmetry

3Ease of manufacture

If uniform roughness is applied in both circumferential and axial directions, then manufacturing is simplified, but wear increases and lateral guidance is insufficient

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidwear behavior
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent specifies different roughness requirements for different directions on the contact surface. The circumferential direction requires lower roughness (0.1-0.8 µm) to minimize wear during rotation, while the axial direction allows higher roughness for improved lateral guidance. This directional quality differentiation optimizes wear behavior without requiring uniformly high manufacturing precision across the entire surface.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the roughness parameter differentially in different directions on the contact surface. By specifying Ra 0.1-0.8 µm in the circumferential direction while allowing higher values in the axial direction, the patent optimizes both wear resistance and lateral guidance performance, achieving better overall performance than uniform roughness configurations.

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 approach reduces wear and production costs while maintaining precise traction force control, improving lateral guidance and ensuring reliable operation during potential slippage situations.

Implementation Method 1

the arithmetic mean roughness value of the contact surface, measured in the circumferential direction of the elevator element, is 0.1 to 0.8 micrometers. One of the advantages of contact surfaces with a roughness according to these specifications is the low level of wear on the elevator suspension element and the contact surfaces of the elevator element itself

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

insufficient roughness of the contact surfaces in the axial direction of the elevator elements can negatively influence the lateral guiding effect, which causes the elevator suspension element to move centrally over the driving and/or deflecting elevator elements

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2006236B1Lift load-bearing member and elevator element for driving or returning of said lift load-bearing member in an elevator system
Publication Date: 2011.09.28 INVENTIO AG
  • EP2006236B1 patent drawingFigure 1~2

AI summary

The elevator installation has a cabin (10) or a platform for carrying persons and goods, and has counter weights arranged to move or slide along a movement track. The counter weights are movably coupled with one another with the help of traction unit or with a drive. The counter weights move or slide along a movement track and is assigned a driving unit or a force transmission arrangement, which is guided or driven by driving disk or driving shaft or a deflection pulley. Independent claims are also included for the following: (1) a force transmission arrangement or a belt like traction unit (2) a manufacturing method for traction unit (3) a manufacturing device for belt like traction unit (4) an elevator system with two cabins.