Transmission Oil Pump Layout for Sealing and Service Access

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Solution Overview

Problem

Existing oil pump arrangements for motor vehicle transmissions face issues with sealing problems and increased installation space requirements, particularly due to externally mounted auxiliary oil pumps, which can lead to leakage and require additional space outside the transmission housing.

Innovation Solution

The oil pump arrangement integrates the pump part within the transmission housing, allowing the pump motor to be mounted externally, eliminating leakage issues and reducing external space requirements. This configuration includes an intermediate shaft for power transmission between the pump motor and pump part, which is articulated to compensate for angular errors and minimize frictional losses, and a control unit connected via electrical lines for efficient operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of repair

If the auxiliary oil pump is mounted externally on the transmission housing, then the pump motor is accessible for replacement, but sealing problems and leakage occur at the connection points

Engineering Contradiction:
ImproveAccessibility of pump motorVSAvoidSealing reliability
Core Design Contradiction:
Ease of repairVSReliability

Solution Approach 1:

The pump motor is nested within the transmission housing, with the pump part positioned inside the oil chamber and the motor integrated into the housing structure. This nested arrangement eliminates external connection points and sealing interfaces, thereby preventing leakage while maintaining system accessibility through the housing's inherent service openings.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The pump motor and transmission housing are merged into a single integrated unit, where the motor is mounted directly on the housing and the pump part is positioned inside the oil chamber. This merging eliminates separate connection points and sealing interfaces between external components, thereby preventing leakage while maintaining system functionality.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of repair

If the auxiliary oil pump is mounted externally on the transmission housing, then the pump motor is accessible for replacement, but additional installation space is required outside the housing

Engineering Contradiction:
ImproveAccessibility of pump motorVSAvoidInstallation space
Core Design Contradiction:
Ease of repairVSArea of stationary object

Solution Approach 1:

The pump motor is nested within the transmission housing structure, utilizing the existing housing volume rather than requiring external mounting space. The motor is positioned inside the housing with the pump part inside the oil chamber, thereby eliminating the need for additional external installation space while maintaining accessibility through service openings.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The pump motor is positioned in the vertical dimension within the housing rather than requiring horizontal external mounting space. By utilizing the vertical space within the housing and positioning the motor above the oil chamber, the design eliminates the need for additional external installation area.

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

3Reliability

If the pump part is positioned inside the oil chamber, then sealing problems are eliminated, but the pump motor becomes less accessible

Engineering Contradiction:
ImproveSealing reliabilityVSAvoidAccessibility of pump motor
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The pump assembly is segmented into the pump part inside the oil chamber and the motor section accessible through service openings. This segmentation allows the pump part to remain sealed within the oil chamber while the motor can be serviced through accessible openings in the housing, maintaining both sealing reliability and ease of repair.

Inventive Principle:
Principle #1Segmentation

4Loss of energy

If the intermediate shaft is articulated to compensate for angular errors, then frictional losses are minimized, but the mechanical complexity increases

Engineering Contradiction:
ImproveFrictional lossesVSAvoidMechanical complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The intermediate shaft is designed as an articulated dynamic connection rather than a rigid fixed connection. This allows the shaft to adapt its angle during operation to minimize frictional losses while transmitting power between the motor and pump part, accepting the necessary increase in mechanical complexity to achieve energy efficiency.

Inventive Principle:
Principle #15Dynamics

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 design prevents sealing issues, reduces external space needs, allows easy replacement of the pump motor without disassembling the gearbox, and enhances efficiency by minimizing frictional losses and heat absorption, while providing independent oil supply for cooling and actuators, optimizing power usage and component cooling.

Implementation Method 1

An intermediate shaft connects the pump part and the pump motor to one another

Methodology Applied
Scientific EffectMechanical power transmission:

Implementation Method 2

The intermediate shaft is articulated to compensate for angular errors

Methodology Applied
Scientific EffectAngular compensation:

Implementation Method 3

a pump motor (4), in particular an electric pump motor, which can be mounted on the housing (5) from the outside

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Data Source

PatentEP3245426B1Oil pump arrangement for a motor vehicle
Publication Date: 2021.05.19 VOLKSWAGEN AG
  • EP3245426B1 patent drawingFigure 1
  • EP3245426B1 patent drawingFigure 2
  • EP3245426B1 patent drawingFigure 3

AI summary

The invention relates to an oil pump arrangement (1) for a motor vehicle, comprising an oil pump (2) having a pump part (3) and an electric pump motor (4), wherein the pump part (3) is in operative connection with the pump motor (4), the pump part (3) and/or the pump motor (4) being mountable to a housing (5), the housing (5) partially delimiting an oil chamber (7). Tightness problems on the pump part (3) are prevented and the required installation space is low because the pump part (3) can be mounted within the housing (5) and the pump motor (4) can be mounted from the outside to the housing (5).