Planetary Gear Drive for Compact Vacuum Interrupter Switching

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Solution Overview

Problem

Existing mechanical drives for low, medium, and high voltage vacuum interrupters and circuit breakers are complex and large, making them unsuitable for applications requiring compact designs and synchronized switching, especially when individual pole driving or concentric devices are needed without a breaker housing.

Innovation Solution

A mechanical drive system utilizing a planetary gear mechanism with a sun cogwheel, planetary cogwheels, and a cogwheel ring, where the pushrod is rotationally connected to the sun cogwheel, allowing for efficient translational movement of the pushrod through a threaded interface, enabling compact in-axis designs and reduced complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If conventional levers and shafts are used to connect switching poles, then mechanical connection is achieved, but the device size and complexity increase significantly

Engineering Contradiction:
Improvemechanical drive complexityVSAvoiddrive system size
Core Design Contradiction:
Device complexityVSVolume of moving object

Solution Approach 1:

The planetary gear mechanism nests multiple cogwheels (sun cogwheel, planetary cogwheels, and cogwheel ring) within a compact concentric arrangement. The pushrod passes through the center of this nested structure, allowing all components to occupy a small radial space while achieving the required mechanical connection between switching poles.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The invention combines multiple functions into a single integrated drive unit: the planetary gear mechanism simultaneously provides mechanical connection, motion transmission, and compact positioning. This merged structure eliminates the need for separate levers and shafts, reducing both device complexity and overall size.

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If conventional mechanical drives are used, then switching function is achieved, but the design freedom for switchgears is limited

Engineering Contradiction:
Improvedesign freedomVSAvoidmechanical drive complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The planetary gear drive mechanism serves multiple functions: it connects switching poles mechanically, enables synchronized switching, and allows flexible positioning within switchgear assemblies. This universal mechanism can be adapted to various switchgear designs without requiring complex custom mechanical linkages for each application.

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

3Volume of moving object

If magnetic drives are used for compact in-axis design, then device size is reduced, but optimal performance is not always achieved

Engineering Contradiction:
Improvedrive system sizeVSAvoidswitching reliability
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The invention replaces magnetic drive mechanisms with a refined mechanical planetary gear system that achieves comparable compactness. The threaded connection between the pushrod and sun cogwheel provides precise, reliable mechanical coupling while maintaining the in-axis compact design, eliminating concerns about magnetic field interference and reliability issues associated with magnetic drives.

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

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 planetary gear system enables compact, efficient, and less complex designs for low, medium, and high voltage switching systems, allowing for simultaneous rotation of multiple drives by a single motor, facilitating synchronized switching and reducing the size and complexity of switchgear.

Implementation Method 1

The pushrod is rotationally connected to the sun cogwheel such that an axis of the pushrod is coaxial with an axis of the sun cogwheel... the rotation of the sun cogwheel in the first rotational direction is configured to move the pushrod along an direction of an axis of the pushrod in a first direction

Methodology Applied
Scientific EffectScrew mechanism: Screw

Data Source

PatentEP3951821B1Drive for a low, medium and high voltage vacuum interrupter
Publication Date: 2024.05.29 ABB (SCHWEIZ) AG
  • EP3951821B1 patent drawingFigure 1
  • EP3951821B1 patent drawingFigure 2
  • EP3951821B1 patent drawingFigure 3

AI summary

The present invention relates to a drive for a low, medium and high voltage switch, comprising: a pushrod (10); a sun cogwheel (30); at least one planetary cogwheel (40); and a cogwheel ring (60): The pushrod comprises a threaded portion (20): The sun cogwheel comprises an inner threaded portion located about an axis of the sun cogwheel. The pushrod is connected to the sun cogwheel such that an axis of the pushrod is coaxial with the axis of the sun cogwheel. The sun cogwheel comprises a plurality of outward facing teeth. An axis of the cogwheel ring is coaxial with the axis of the sun cogwheel. The cogwheel ring comprises a plurality of inward facing teeth. The at least one planetary cogwheel is located between the sun cogwheel and the cogwheel ring. The at least one planetary cogwheel comprises a plurality of outward facing teeth, and some teeth of the at least one planetary cogwheel are engaged with some teeth of the sun cogwheel and some other teeth of the at least one planetary cogwheel are engaged with some teeth of the cogwheel ring. In a first switching action: a rotation of the at least one planetary cogwheel about the axis of the sun cogwheel in a first rotational direction is configured to rotate the sun cogwheel in the first rotational direction; and the rotation of the sun cogwheel in the first rotational direction is configured to move the pushrod along the axis of the pushrod in a first direction.