Compact Geared Motor Assembly With Splash Oil Cooling

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Solution Overview

Problem

Existing compact motor and gear assemblies face challenges in achieving both compactness and effective cooling, particularly due to the difficulty in cooling the drive motor when it is housed under a common cover with the gear stage, leading to potential thermal issues and maintenance complications.

Innovation Solution

The drive motor and gear stage are integrated within a single chamber, allowing for direct splash oil cooling from the gear stage, eliminating the need for external cooling and reducing the complexity of sealing, while the gearbox housing acts as a heat sink for the motor, enhancing thermal connection and noise insulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the drive motor is integrated under a common cover housing with the gear stage to achieve compactness, then the overall assembly size is reduced, but the cooling of the drive motor becomes difficult

Engineering Contradiction:
Improveassembly sizeVSAvoidmotor cooling
Core Design Contradiction:
Volume of moving objectVSTemperature

Solution Approach 1:

The drive motor and gear stage are merged into a single common cover housing, eliminating separate cooling chambers and integrating the cooling function directly into the gear stage lubrication system. This merging achieves both compactness and effective cooling by using the same space and fluid system for both mechanical transmission and motor thermal management.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The gear stage serves a dual function: mechanical power transmission and self-cooling of the drive motor. The lubricating oil that naturally circulates through the gear stage for its own lubrication needs simultaneously cools the drive motor, allowing the system to cool itself without external cooling mechanisms.

Inventive Principle:
Principle #25Self-service

2Temperature

If the drive motor is arranged separately outside the transmission to facilitate cooling, then the cooling is improved, but the assembly becomes less compact

Engineering Contradiction:
Improvemotor coolingVSAvoidassembly size
Core Design Contradiction:
TemperatureVSVolume of moving object

Solution Approach 1:

The drive motor and transmission are combined into a single integrated unit housed under one common cover, eliminating the need for separate cooling chambers. The gear stage and motor share the same spatial envelope, achieving compactness while maintaining cooling effectiveness through the integrated lubrication system.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If a seal on the drive shaft is used to protect against external contaminants, then protection is improved, but maintenance complexity and friction increase

Engineering Contradiction:
Improveprotection against contaminantsVSAvoidsealing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The drive shaft is completely extracted from the housing, eliminating the need for seals, bearings, or any interface between the rotating shaft and stationary housing. The drive shaft becomes an internal component entirely contained within the housing, removing the source of potential leakage and wear problems.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The enclosed drive shaft design makes the system self-sufficient by eliminating wear-prone sealing components. The system protects itself against contaminants through the complete enclosure of the drive shaft, requiring no maintenance for seal replacement or adjustment.

Inventive Principle:
Principle #25Self-service

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 efficient cooling without external air cooling, reduces maintenance needs, and provides a durable, compact, and low-noise drive arrangement with improved thermal management and reduced noise emissions.

Implementation Method 1

a direct spray cooling of the drive motor by splash oil is formed of the gear stage

Methodology Applied
Scientific EffectSplash oil cooling: Convection

Implementation Method 2

the gearbox housing acts as a heat sink for the motor, enhancing thermal connection

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 3

the gearbox housing acts as a heat sink for the motor, enhancing thermal connection

Methodology Applied
Scientific EffectHeat sink: Heat Sink

Data Source

PatentEP3358225B1Compact transmission motor assembly
Publication Date: 2021.12.29 GETRIEBEBAU NORD GMBH & CO
  • EP3358225B1 patent drawingFigure 1~2
  • EP3358225B1 patent drawingFigure 3a~4
  • EP3358225B1 patent drawingFigure 5

AI summary

Geared motor arrangement consisting of a gear (2) and a drive motor (5) with a housing (3) which surrounds a gear chamber (30). At least one gear stage (4) is arranged in the gear chamber (30). A drive shaft (46) with a drive pinion (45) and also a driven shaft (42) with a driven gear (41) are arranged in the gear chamber (30), the drive pinion (45) driving the driven gear (41). According to the invention, the gear stage (4) and the drive motor (5) of a type with a drive pinion (45) arranged between bearings (47, 48) are arranged together in the same gear chamber (30), with direct spray cooling of the drive motor (5) by spray oil from the Gear stage (4) is formed. Due to the arrangement in one and the same chamber (30), the drive motor (5) is thermally optimally connected. The spray cooling of the gear stage results in a good cooling effect without having to rely on external air cooling. In addition, there is no opening for the motor shaft, including the wear-prone sealing ring for it. This increases robustness and durability. Furthermore, noise emissions are reduced since the gear chamber acts like an encapsulation of the drive motor.