Insulated Clutch Sleeve Structure to Prevent Voltage Flashover

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Solution Overview

Problem

Existing couplings in vehicle drives, particularly in rail vehicles, fail to reliably prevent electrical contact between input and output sides due to high capacitance and inhomogeneous insulation layers, leading to voltage flashover and reduced heat dissipation.

Innovation Solution

A clutch design featuring a metallic first hollow cylinder and an electrically insulating second hollow cylinder made of materials like epoxy resin or glass fiber-reinforced plastics, with knurling on the lateral surfaces and a dielectric constant of at most 9, ensuring complete electrical insulation and uniform layer thickness, positioned away from the gearing to prevent thermal insulation and maintain heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an insulating layer is applied to insulate the shaft connection elements, then electrical contact is prevented, but the layer thickness is inhomogeneous leading to reduced insulating effect

Engineering Contradiction:
Improveelectrical contact preventionVSAvoidlayer thickness uniformity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent uses a multi-layer composite insulation structure where each layer can be independently controlled for thickness and material properties. This approach compensates for manufacturing variations in individual layers, ensuring consistent overall insulation performance and uniform effective thickness.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Different regions of the insulation structure have different layer configurations and material properties optimized for local requirements. The insulating layers are arranged with varying thicknesses and materials to achieve uniform effective insulation across the entire clutch assembly, compensating for areas with manufacturing variations.

Inventive Principle:
Principle #3Local quality

2Reliability

If the insulating layer is placed in the immediate vicinity of the gearing, then electrical insulation is achieved, but thermal insulation occurs reducing heat dissipation and increasing clutch temperatures

Engineering Contradiction:
Improveelectrical insulationVSAvoidclutch temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The insulation structure is designed with spatially varying properties: electrically insulating materials are positioned where electrical isolation is critical, while thermally conductive pathways are maintained in regions requiring heat dissipation. This local optimization allows simultaneous achievement of electrical insulation and thermal management.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The clutch assembly is segmented into distinct thermal and electrical zones. The insulation structure is segmented to provide electrical isolation only where necessary, while maintaining thermal pathways in other regions. This segmentation allows the clutch to achieve electrical insulation without compromising overall heat dissipation capability.

Inventive Principle:
Principle #1Segmentation

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 solution effectively prevents electrical contact and voltage flashover while allowing efficient torque transmission, reducing clutch temperatures and production costs through a simple and cost-effective method.

Implementation Method 1

the second hollow cylinder consists of an electrically insulating material... ensuring complete electrical insulation

Methodology Applied
Scientific EffectElectrical insulation: Electrical Resistance

Implementation Method 2

a dielectric constant of at most 9, ensuring complete electrical insulation and uniform layer thickness

Methodology Applied
Scientific EffectCapacitance reduction through dielectric material: Capacitance

Implementation Method 3

with knurling on the lateral surfaces... at least the bore on its inner lateral surface, which faces the input or output shaft, also has knurling at least partially

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3655674B1Clutch and method for the production thereof
Publication Date: 2021.05.12 KWD KUPPLUNGSWERK DRESDEN GMBH
  • EP3655674B1 patent drawingFigure 1

AI summary

The invention relates to the field of mechanical engineering and relates to a clutch as can be used, for example, in vehicle drives, in particular rail vehicle drives. It is the problem of the present invention to specify a clutch, by way of which the electric contact between the drive side and the output side of the clutch is prevented reliably, and to specify a simple and inexpensive method for the production thereof. The problem is solved by way of a clutch, at least consisting of a clutch half on the drive side and a clutch half on the output side, wherein at least one clutch half has at least two hollow cylinders which are arranged above one another and are arranged in a bore of the clutch half, wherein the second hollow cylinder consists of electrically insulating material, and wherein at least the first hollow cylinder, at least on its outer circumferential surface, and at least the inner circumferential surface of the bore have knurling at least in part.