Transmission Double Wall Structure for Sealing and Lubrication

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Solution Overview

Problem

Existing gearboxes face challenges in maintaining safe operation due to internal space constraints, lubricant volume, pressure changes during temperature fluctuations, and seal stress, which affect sealing and protection.

Innovation Solution

A transmission design featuring a double wall structure with identical cover parts, reduced internal volume, and a radial intermediate region filled with air or filler material, which stabilizes the seals and reduces pressure differences, allowing for efficient lubricant distribution and reduced friction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the internal volume of the gearbox is reduced, then the amount of lubricant is reduced, but the space for the driving shaft and lubricant distribution is constrained

Engineering Contradiction:
Improveamount of lubricantVSAvoidinternal volume
Core Design Contradiction:
Quantity of substanceVSVolume of moving object

Solution Approach 1:

The gearbox is divided into two separate volumes: an internal volume containing the driving shaft and gear components, and an intermediate volume between the outer wall and first wall region. This segmentation allows the internal volume to be minimized for lubricant reduction while the intermediate volume provides additional space for lubricant storage and distribution to the driving shaft area.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the internal volume is reduced, then the sealing performance is improved due to reduced pressure changes, but the space for accommodating components is reduced

Engineering Contradiction:
Improvesealing performanceVSAvoidinternal volume
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The solution moves from a single-volume design to a multi-volume design by adding the intermediate volume between the outer wall and first wall region. This dimensional expansion in the radial direction allows the internal volume to be reduced for better sealing, while the intermediate volume compensates for the lost space by providing alternative accommodation for components and lubricant distribution pathways.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Ease of manufacture

If identical cover parts are used, then manufacturing costs are reduced, but the adaptability to different bearing arrangements is constrained

Engineering Contradiction:
Improvemanufacturing costsVSAvoidadaptability to bearing arrangements
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The first and second cover parts are designed as identical components that can accommodate either a first bearing or a second bearing in their first ring areas. This universal design allows the same cover part to serve multiple functions and positions, reducing manufacturing costs while maintaining adaptability to different bearing arrangements through the standardized interface and support structure provided by the housing part.

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

4Strength

If the double wall structure is used, then the rigidity is improved, but the device complexity is increased

Engineering Contradiction:
ImproverigidityVSAvoiddevice complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The double wall structure segments the gearbox into distinct radial zones: an outer wall, an intermediate volume, and a first wall region. This segmentation provides rigidity through the distributed wall structure while managing complexity by creating clearly defined functional zones with specific purposes (sealing, lubricant distribution, component accommodation), making the overall design more manageable despite the additional structural elements.

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 design enhances sealing performance, reduces internal volume, and improves lubrication efficiency, thereby increasing the transmission's load capacity and service life while minimizing friction-related heat loss.

Implementation Method 1

pressure changes during temperature fluctuations

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

an electrically controllable heating element can be arranged in the intermediate space region so that when the gear has cooled down, the intermediate region can be heated up quickly

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 3

due to the resulting increase in the pressure difference to the internal volume of the gear

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 4

Grease is the preferred lubricant, or alternatively, gear oil

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP3966475B1Transmission comprising a housing part, a first cover part and a second cover part
Publication Date: 2025.08.06 SEW EURODRIVE GMBH & CO KG
  • EP3966475B1 patent drawingFigure 1
  • EP3966475B1 patent drawingFigure 2
  • EP3966475B1 patent drawingFigure 3

AI summary

The invention relates to a transmission comprising a housing part, a first cover part and a second cover part, wherein a shaft is rotatably mounted via a first and a second bearing, wherein the first bearing is accommodated in a first ring region of the first cover part, wherein the first ring region is inserted and/or accommodated in a recess introduced into an ring wall of the housing part, wherein the ring wall has a first wall region, a second wall region and a transition region, wherein the first wall region is arranged in a first circumferential angular range, wherein the second wall region is arranged in a second circumferential angular range, which is spaced apart from the first transition region, wherein the transition region connects the two wall regions, and wherein the region covered by the first wall region in the axial direction encompasses the region covered by the second wall region in the axial direction.