Eccentric Lubricant Pump Rotor with Form-Locking Drive Connection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing automotive lubricant pumps, particularly gear ring pumps, face issues with slippage between the drive ring gear and rotor ring body due to high torque, leading to potential interruptions in lubricant supply and damage to traction motors, especially during cold starts when lubricant viscosity is high.
Innovation Solution
The design incorporates a rotatable pump rotor with an eccentrically arranged rotor hub and rotor ring, featuring a non-positive press connection and a positive connection via cylindrical pins distributed over the circumference, which prevents slippage and reduces the load on the press connection, ensuring reliable lubricant supply and anti-twist protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a purely frictional press connection is used between the drive gear ring and rotor ring body, then the manufacturing cost is reduced and assembly is simplified, but slippage occurs due to high torque leading to unreliable lubricant supply
Solution Approach 1:
The connection between drive gear ring and rotor ring body is segmented into multiple functional elements: a press fit connection for general torque transmission and additional form-locking connections (such as keys, splines, or protrusions) for preventing slippage during high-torque conditions. This segmentation allows each connection type to perform its specialized function optimally.
Solution Approach 2:
The connection system uses composite joining methods combining friction-based press fit (force-locking) with geometry-based form-locking elements. This composite approach leverages the advantages of both connection types: the press fit provides uniform stress distribution and easy assembly, while the form-locking elements provide positive anti-slippage protection.
2Reliability
If a strong press fit is used to prevent slippage, then torque transmission reliability is improved, but the press connection becomes oversized increasing manufacturing complexity and cost
Solution Approach 1:
Instead of using an excessively strong press fit that would require oversized components and complex manufacturing, the solution uses a moderate press fit combined with supplemental form-locking elements. The form-locking elements provide the additional torque capacity needed, allowing the press fit to be sized appropriately without being oversized.
Solution Approach 2:
Form-locking elements act as intermediaries between the drive gear ring and rotor ring body, facilitating torque transmission without requiring an excessively strong press fit. These intermediate elements (keys, splines, protrusions) transfer torque through geometric engagement rather than relying solely on friction from a strong press fit.
3Strength
If the drive gear ring is made of high-strength hardened steel for wear resistance, then wear resistance in the external drive gearing area is improved, but the self-lubricating properties in the pump chamber area are reduced
Solution Approach 1:
The drive gear ring exhibits local quality variations: the external drive gearing area is made of high-strength hardened steel for wear resistance, while the pump chamber area (internal gear engagement zone) has different surface properties or material composition optimized for self-lubrication. This localized differentiation allows each area to have the properties needed for its specific function.
Solution Approach 2:
The material parameters of the drive gear ring are changed spatially: hardness and strength are increased in the external drive gearing area through hardening processes, while the pump chamber area maintains softer, more lubrication-friendly properties. This parameter change allows the single component to satisfy conflicting requirements in different regions.
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 solution provides a reliable and cost-effective lubricant pump that prevents slippage, maintains lubricant supply integrity, and reduces manufacturing and assembly costs by utilizing a positive connection that absorbs torque, enhancing wear resistance and self-lubrication properties.
Implementation Method 1
the rotor ring body and drive gear ring are connected by means of a form-locking connection. Suitable form-locking connections can, for example, be corresponding polygonal or other non-circular contours on the rotor ring body and the drive gear ring, but also additional separately introduced connecting elements that create a form-locking connection
Implementation Method 2
The rotor ring body and drive gear ring are joined together in a force-locking manner, for example via a press connection... In addition to the force-locking connection between the rotor ring body and the drive gear ring, which is typically formed by a relatively strong press fit
Implementation Method 3
The rotor hub is arranged eccentrically with respect to the rotor ring, with the internal pump gearing of the rotor ring meshing with the external pump gearing of the rotor hub... individual fluidically separated pump chamber sections are formed in the tooth spaces between the rotor ring and the rotor hub, the volume of which increases or decreases over a full revolution of the pump rotor
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to an automotive lubricant pump (10) comprising a stationary pump housing (12), a rotatable pump rotor (20) with an outer rotor ring (22) having internal pump teeth (23), and an inner rotor hub (28) arranged eccentrically to the rotor ring (22) and having external pump teeth (29), the external pump teeth (29) of which mesh with the internal pump teeth (23) of the rotor ring (22), whereby the rotor ring (22) and the rotor hub (28) together with the pump housing (12) form a pump chamber (14), wherein the rotor ring (22) is formed by an inner rotor ring body (24) and a separate outer drive gear ring (26), wherein the drive gear ring (26) is positively connected to the rotor ring body (24) and has external drive teeth (27). by means of which the pump rotor (20) is mechanically driven,wherein the rotor ring body (24) and the drive gear ring (26) are connected by means of a positive-locking connection (30). The positive-locking connection (30) serves as an additional anti-rotation device and as a means of torque transmission, thereby reducing the load on the press fit, which in turn reduces its interference fit compared to a pure press fit.