Tandem Pump Layout With Separate Sumps and Mixed Flow Directions

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing tandem pumps face strict installation space requirements, and integrating a dry sump function into these pumps results in acoustic disturbances and air leakage between sumps, which are not adequately addressed in prior art designs.

Innovation Solution

The use of two pump types with different flow directions, specifically a gerotor pump for axial flow and an external gear pump for radial flow, allows for optimal positioning within the available installation space, preventing size increases and ensuring separate inlets for each sump, while a radial shaft seal prevents air ingress and mechanical coupling maintains a defined fluid ratio.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a dry sump function is integrated into a tandem pump, then the pump can supply hydraulic consumers effectively, but acoustic disturbances and air leakage occur between sumps

Engineering Contradiction:
Improvehydraulic fluid supply capabilityVSAvoidacoustic disturbances and air leakage
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The pump is divided into two independent pumping circuits (dry sump pump and main sump pump) with separate inlets and outlets, each handling its own fluid path. This segmentation prevents air and fluid mixing between the circuits while maintaining effective hydraulic supply to consumers.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A common housing structure serves as an intermediary that accommodates both independent pump circuits while providing acoustic isolation and preventing air leakage between them. The housing acts as a mediator that allows both functions to coexist without interfering with each other.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Area of stationary object

If two pump types with different flow directions are used, then installation space requirements are met, but device complexity increases

Engineering Contradiction:
Improveinstallation space footprintVSAvoidpump configuration complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

Two different pump types (gerotor pump with axial flow and external gear pump with radial flow) are merged into a single common housing, sharing mechanical drive components and sealing structures. This combination achieves compact installation space while the integrated design manages the complexity through commonality of certain elements.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The common housing and drive mechanism serve multiple functions: accommodating both pump types, providing mechanical coupling between them, ensuring sealing between circuits, and enabling compact installation. This multi-functionality reduces overall complexity despite using different pump types.

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

3Adaptability or versatility

If separate inlets are provided for dry sump and main sump, then fluid can be drawn from different reservoirs, but device complexity increases

Engineering Contradiction:
Improvefluid source flexibilityVSAvoidinlet configuration complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The inlet system is segmented into separate inlet ports for the dry sump pump and main sump pump, allowing each pump to draw fluid from different reservoirs independently. This segmentation provides the required flexibility while the modular design keeps the complexity manageable.

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

This configuration enables a compact, cost-effective tandem pump that meets installation space requirements without acoustic disturbances and air leakage, effectively supplying hydraulic fluid to consumers while handling contamination and air ingress.

Implementation Method 1

A tandem pump (1) for an electric axle of a motor vehicle with a dry sump (2) through which hydraulic fluid can be pumped from a transmission compartment to a hydraulic compartment and a main sump (3) through which hydraulic fluid can be pumped from the hydraulic compartment to the hydraulic consumer

Methodology Applied
Scientific EffectPositive displacement pumping: Pump

Implementation Method 2

The tandem pump (1) has a radial shaft seal which prevents air from passing from the dry sump side to the main sump side

Methodology Applied
Scientific EffectMechanical sealing:

Data Source

PatentEP4463614B1Tandem pump comprising a main flow and a dry sump flow
Publication Date: 2026.03.11 SCHAEFFLER TECHNOLOGIES AG & CO KG
  • EP4463614B1 patent drawingFigure 1~4
  • EP4463614B1 patent drawingFigure 5~7

AI summary

The invention relates to a tandem pump (1) for an electric axle of a motor vehicle, comprising a dry sump flow (2) via which hydraulic fluid can be delivered from a transmission chamber into a hydraulic chamber, and a main flow (3) via which hydraulic fluid can be delivered from the hydraulic chamber to a hydraulic consumer, wherein the dry sump flow (2) and the main flow (3) are formed by types of pumps having different inflow directions.