External Gear Pump Stage Layout for Compact Dry Sump Lubrication
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Solution Overview
Problem
Current dry sump lubrication systems for vehicles, particularly in electric vehicles, require improvement in terms of compactness and efficiency, as they often involve more components and higher friction losses due to the arrangement of pump stages and gears.
Innovation Solution
A plug-in pump design with two pump suction stages and two pump pressure stages, utilizing a common drive shaft and arranged in a specific gear configuration to minimize the number of external gears, allowing for a compact and efficient lubrication system with only six external gears, and a hydraulic connection that reduces weight and friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If multiple pump stages are arranged in conventional configurations, then the lubrication system can deliver required flow rates, but the system becomes less compact and has higher friction losses
Solution Approach 1:
The patent implements a nested configuration where a second pump stage is positioned inside the first pump stage, with the second drive shaft extending through the first drive shaft. This nesting arrangement allows multiple pump stages to occupy overlapping spatial volumes, significantly reducing the overall pump volume while maintaining the required delivery capacity through combined output of both stages
Solution Approach 2:
The patent transitions from conventional side-by-side or serial pump stage arrangements to a three-dimensional nested configuration. By utilizing radial and axial spatial dimensions simultaneously, the design achieves compactness without compromising delivery volume, as the inner pump stage operates independently within the outer stage's volume
2Productivity
If multiple external gears are used to achieve required pump stages, then the delivery volume is sufficient, but the number of rotating components increases leading to higher friction losses
Solution Approach 1:
The patent merges the functions of multiple pump stages into a unified nested structure where the second pump stage is integrated within the first stage. This combination reduces the total number of independent rotating components and external gears required, thereby minimizing friction losses while achieving the necessary delivery volume through the combined output of both stages
Solution Approach 2:
The nested pump stage configuration allows the same spatial volume to serve multiple functions simultaneously - the outer stage provides pumping capacity while the inner stage adds additional capacity without requiring separate housing or mounting structures. This multi-functionality reduces the overall number of components and associated friction interfaces
3Productivity
If more pump stages and gears are installed, then the lubrication capacity increases, but the system weight increases
Solution Approach 1:
By nesting the second pump stage within the first stage, the patent eliminates the need for separate housings, mounting structures, and supporting components for each stage. This nested arrangement significantly reduces the overall pump weight while maintaining enhanced lubrication capacity through the combined output of both pump stages operating in conjunction
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 proposed solution results in a compact, efficient dry sump system with reduced friction losses and weight, enabling effective lubrication for vehicle transmissions and electric motors, while maintaining a minimal number of rotating components.
Implementation Method 1
The pump suction stages are formed by a first arrangement of at least three intermeshing external gears located in a first plane. The pump pressure stages, however, are formed by a second arrangement of at least three intermeshing external gears located in a second plane
Implementation Method 2
at least two pump suction stages for sucking in lubricating oil from a first oil tank acting as a dry sump and for conveying the lubricating oil into a second oil tank acting as an oil tank, and at least two pump pressure stages for sucking in the lubricating oil from the second oil tank and conveying it to the consumer
Data Source
Figure 1
Figure 1a
Figure 2
AI summary
Proposed is a pump stage assembly (2) for supplying lubricating oil to at least one consumer, comprising: - at least two pump suction stages (4, 6) and - at least one pump pressure stage (8), said pump suction stages and said pump pressure stage being arranged at a distance relative to each other in a pump housing PG and having a common drive shaft (56), wherein the pump suction stages are formed by a first assembly (ZA1) of at least three intermeshing external gears (12, 14, 16), and the pump pressure stage is formed by a second assembly (ZA2) of two intermeshing external gears (18, 20). As a result, at least two of the respective gear centres (ZM1, ZM2, ZM3) of the first external gear assembly and the respective gear centres (ZM4, ZM5) of the second external gear assembly are disposed on a common plane E - E, which intersects the pump housing PG in a longitudinal direction X - X.