Electric Pump Journal Bearing Load Capacity
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Solution Overview
Problem
The existing pump unit designs face limitations in load-bearing capability due to uneven distribution of hydraulic pressure forces across plain bearings, with the bearing facing the rotor experiencing greater stress, leading to limited working pressure and potential structural issues.
Innovation Solution
The design increases the load-bearing capability of the first plain bearing by making its diameter larger than the second, creating a step-shaped shoulder, and integrates an armature section with permanent magnets interacting with an electric stator for an efficient electric drive, while the stator is integrated into the housing's circumferential wall for easy manufacturing and sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the first plain bearing is made larger in diameter to increase load-bearing capability, then the load-bearing capability of the first plain bearing is improved, but the axial length of the pump unit increases
Solution Approach 1:
The drive shaft is designed with different diameters at different locations: a first bearing section with larger diameter for the first plain bearing, a second bearing section with smaller diameter for the second plain bearing, and an armature section with intermediate diameter. This local differentiation allows each bearing to have the appropriate size for its load requirements without uniformly increasing the entire shaft diameter, thus resolving the contradiction between load-bearing capability and axial length.
2Strength
If the first bearing section diameter is made larger than the second bearing section diameter, then the load-bearing capability of the first plain bearing is improved, but the manufacturing complexity increases
Solution Approach 1:
The drive shaft is segmented into three distinct sections with different diameters: the first bearing section, the armature section, and the second bearing section. Each section can be manufactured separately or as part of a composite structure, allowing for simplified manufacturing of each segment while maintaining the overall functional requirements. This segmentation reduces the complexity compared to a single-diameter shaft requiring complex reinforcement at bearing locations.
3Power
If the armature section diameter is set between the first and second bearing section diameters, then the electric motor efficiency is optimized, but the device complexity increases
Solution Approach 1:
The armature section is merged with the drive shaft, combining the rotational function of the drive shaft with the electromagnetic function of the armature. The permanent magnets are arranged on the circumference of the armature section, which is integrated into the drive shaft structure. This merging eliminates the need for separate armature and shaft components, reducing overall device complexity while maintaining optimized motor efficiency through the intermediate diameter design.
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 enhances the load-bearing capacity of the first plain bearing, allows for a shorter axial construction, and enables an efficient and cost-effective electric drive with optimized motor efficiency and easy demolding from injection molding dies.
Implementation Method 1
permanent magnets which interact with an electric winding of an electric stator of an electric motor which surrounds the armature section of the drive shaft in an annular manner
Data Source
AI summary
Pump units include a rotatably arranged rotor (3) that is driven by a drive shaft (2), wherein the drive shaft (2) has a first bearing section (18) facing towards the rotor (3), and a second bearing section (19) facing away from the rotor (3). The first bearing section (18) is a first sliding bearing (20), and the second bearing section (19) is a second sliding bearing (21). The load-bearing capacity of the first sliding bearing (20) is limited by a predetermined working pressure in the pump unit. In the pump unit according to the invention, the load-bearing capacity of the sliding bearing (20) facing towards the rotor (3) is increased. According to the invention, the diameter of the first bearing section (18) of the drive shaft (2) and the first sliding bearing (20) is larger than the diameter of the second bearing section (19) and the second sliding bearing (21).