Drivetrain Oil Reservoir Layout for Pump-Free Gear Lubrication

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Solution Overview

Problem

Existing drive train designs require separate oil pumps for lubrication and cooling, leading to reduced efficiency and increased structural complexity and costs, particularly due to the need for additional oil sump areas and flow channels.

Innovation Solution

An oil container is positioned between the two gear stages, extending parallel to the gears, with integrated oil inlet and outlet areas that utilize the rotating axle drive gear to convey oil from the oil sump area to the container and then to other components, eliminating the need for a separate electrically driven pump and simplifying the design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate electrically driven oil pump is used to supply oil to bearings and components not in direct contact with the oil sump area, then lubrication and cooling of these components is improved, but the efficiency of the drive train is reduced and design complexity and costs increase

Engineering Contradiction:
Improvelubrication and cooling of componentsVSAvoiddesign complexity and costs
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The oil reservoir uses the rotating axle drive gear to automatically pump oil from the oil sump area to the reservoir and then to other components. The system serves itself without requiring an external electrically driven pump, eliminating the associated complexity and costs while maintaining reliable lubrication and cooling.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The oil reservoir acts as an intermediary component between the oil sump area and the components requiring lubrication. It receives oil from the sump area via the rotating gear and distributes it to bearings and other components, eliminating the need for a direct pump connection.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the intermediate shaft with gears is mounted above the drive shaft and above the wheel drive shafts, then the coaxial drivetrain layout is achieved, but the gears do not have direct contact with the oil sump area leading to increased splashing losses and reduced efficiency

Engineering Contradiction:
Improvedrivetrain efficiencyVSAvoidsplashing losses
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The oil reservoir serves as an intermediary that delivers oil directly to the gears on the intermediate shaft, eliminating the need for these gears to splash in the oil sump area. This reduces splashing losses and improves overall drivetrain efficiency while maintaining the coaxial layout.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The oil reservoir extracts oil from the oil sump area and delivers it directly to the gears on the intermediate shaft, removing the harmful splashing action while maintaining the necessary lubrication. This separates the lubrication function from the splashing mechanism.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If a second, additional oil sump is created in the upper housing area to lubricate gears on the intermediate shaft, then lubrication of these gears is improved, but the structural complexity and installation space requirements increase

Engineering Contradiction:
Improvelubrication of gears on intermediate shaftVSAvoidinstallation space
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

Instead of creating a second oil sump in the upper housing area (vertical dimension), the invention uses a horizontal oil delivery system where the oil reservoir receives oil from the lower sump area and transports it horizontally to the gears on the intermediate shaft. This eliminates the need for additional vertical space.

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

Solution Approach 2:

The oil reservoir acts as an intermediary that bridges the vertical distance between the lower oil sump area and the upper intermediate shaft gears, delivering oil without requiring a second sump in the upper area. This maintains compact vertical spacing while ensuring proper lubrication.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution enhances the efficiency of the drive train by reducing the need for additional oil pumps and simplifying the design, thereby lowering costs and installation space requirements while ensuring effective lubrication and cooling of components.

Implementation Method 1

The axle drive gear is arranged to convey oil from the oil sump area into the interior of the oil reservoir by means of its rotation

Methodology Applied
Scientific EffectMechanical conveyance:

Implementation Method 2

supply oil to bearings or other components of the transmission for lubrication

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 3

cooling of gears arranged on the intermediate shaft of the transmission

Methodology Applied
Scientific EffectCooling: Cooling

Data Source

PatentEP3693634B1Drive train of a vehicle
Publication Date: 2024.05.22 VOLKSWAGEN AG
  • EP3693634B1 patent drawingFigure 1
  • EP3693634B1 patent drawingFigure 2
  • EP3693634B1 patent drawingFigure 3

AI summary

The invention relates to an oil reservoir (1) for cooling and/or lubricating bearings (15, 16, 17) of a drive train (2) of a vehicle, in particular a motor vehicle, wherein the drive train (2) comprises at least one drive shaft (3), at least one transmission (4), at least one differential (5) and at least one wheel drive shaft (6, 7), wherein the differential (5) comprises at least one axle drive gear (5a) and the axle drive gear (5a) engages with at least one gear (4b) of the transmission (4), wherein at least one oil sump area (9) is provided and/or is present, and wherein the axle drive gear (5a) and/or a gear (4b) of the transmission (4) is arranged to splash at least partially in the oil sump area (9), wherein the gears of the transmission (4) and/or the axle drive gear (5a) form at least two gear stages (I, II) and two gears (4b, 4c) of the gearbox (4) are arranged on an intermediate shaft (8),and wherein at least one wheel drive shaft (6, 7) is arranged coaxially to the drive shaft (3) and the intermediate shaft (8) of the transmission (4) is arranged substantially on the side of the drive shaft (3) and/or the wheel drive shaft (6, 7) opposite the oil sump area (9). The design complexity of a drive train is thereby reduced, or the efficiency of a drive train (2) is thereby increased, by the fact that the oil reservoir (1) is functionally designed and/or arranged such that the oil reservoir (1) is located in the area between the two gear stages (I, II) and substantially on the side of the drive shaft (3) and/or the wheel drive shaft (6, 7) opposite the oil sump area (9).