Window Sash Drive With Torus Gear for Compact High Reduction

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Solution Overview

Problem

Existing window and door drives face challenges with high gear ratios leading to low efficiency, increased complexity, and high manufacturing costs due to limited installation space, often using small motors with low torque and requiring multiple spur gear stages.

Innovation Solution

The drive incorporates a torus wheel driven by a motor shaft and a bow wheel with a spirally arranged tooth, replacing conventional helical gears, allowing for high efficiency and compact design through a three-stage gearbox with a spiral gear as the input stage, reducing the need for additional spur gear stages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If high gear ratios are used to achieve the required torque with small motors, then the installation space is reduced, but the efficiency significantly decreases below 35 percent

Engineering Contradiction:
Improveinstallation spaceVSAvoidefficiency
Core Design Contradiction:
Volume of moving objectVSLoss of energy

Solution Approach 1:

The patent changes the fundamental gear mechanism from conventional helical or worm gears to a torus wheel with spiral toothing engaged with a bow wheel. This parameter change in the gear type enables achieving high gear ratios (greater than 100) while maintaining high efficiency (approximately 50 percent), directly resolving the contradiction between compact size and energy efficiency.

Inventive Principle:
Principle #35Parameter changes

2Force

If multiple spur gear stages are used to achieve high gear ratios, then the required torque is obtained, but the device complexity and manufacturing costs increase

Engineering Contradiction:
ImprovetorqueVSAvoidgearbox stages
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The patent merges the functions of multiple spur gear stages into a single torus wheel and bow wheel mechanism. The torus wheel with spiral toothing directly engages with the bow wheel to achieve the required high gear ratio, eliminating the need for separate helical gear and multiple spur gear stages, thus reducing complexity and manufacturing costs while maintaining the required torque output.

Inventive Principle:
Principle #5Merging (Combining)

3Stability of the object's composition

If conventional helical gear or worm gear is used for power transmission, then the mechanism is non-reversible, but the efficiency is reduced and more gear stages are required

Engineering Contradiction:
Improvenon-reversibilityVSAvoidgear stages
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent changes the gear mechanism from conventional helical or worm gears to a torus wheel with spiral toothing engaged with a bow wheel. This parameter change enables the mechanism to maintain non-reversibility (preventing the sash from moving backward) while achieving high efficiency and high gear ratio in a single stage, eliminating the need for additional gear stages.

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 configuration achieves a gear ratio greater than 100, enhances power transmission, and allows for a more compact and cost-effective drive design, enabling faster operation and reduced manufacturing costs.

Implementation Method 1

the gear unit has a torus wheel driven by the motor shaft and a bow wheel engaged with the torus wheel, wherein the torus wheel has a rolling surface with a toothing with at least one spirally arranged tooth and the bow wheel has a cylindrical rolling surface with several teeth

Methodology Applied
Scientific EffectSpiral gear mechanism: Gear

Data Source

PatentEP4644651A1Drive
Publication Date: 2025.11.05 GEZE GMBH
  • EP4644651A1 patent drawingFigure 1~3
  • EP4644651A1 patent drawingFigure 4~5
  • EP4644651A1 patent drawingFigure 6~8

AI summary

The present invention relates to a drive, in particular for a window or door sash, comprising a housing, a motor, and a gear unit housed in the housing for driving an output shaft, wherein the output shaft is configured to be connected to a force transmission element for the sash for opening and/or closing the sash. The gear unit has a torus wheel driven by the motor shaft and a curved wheel meshing with the torus wheel, wherein the torus wheel has a rolling surface with a toothing having at least one helically arranged tooth, and the curved wheel has a cylindrical rolling surface with several teeth.