Screw Compressor Bearing Nesting Reduces Drive Shaft Length
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Increasing the size of screw compressors leads to longer drive shafts and larger bearings, resulting in higher costs due to the use of expensive materials like carbon steel or molybdenum steel, and increased loads on bearings.
Innovation Solution
At least a portion of the first bearing is disposed inside the screw rotor, reducing the distance between bearings and the length of the drive shaft, thereby reducing the increase in cost and bearing size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the compressor size is increased, then the compression capacity is improved, but the drive shaft length and bearing size increase leading to higher cost
Solution Approach 1:
The first bearing is disposed inside the screw rotor, nesting the bearing within the rotor structure. This allows the bearing to be positioned closer to the motor, reducing the drive shaft length while maintaining the required support function, thus resolving the contradiction between compression capacity and drive shaft length
Solution Approach 2:
The bearing arrangement moves from a conventional external positioning to an internal positioning within the screw rotor. This spatial reconfiguration in the radial dimension enables shorter axial distance between motor and bearing, reducing drive shaft length while preserving compression capacity
2Length of stationary object
If the drive shaft length is increased, then the bearing distance is increased, but the load on bearings increases and cost increases
Solution Approach 1:
By nesting the first bearing inside the screw rotor, the bearing is positioned optimally to reduce the span of the drive shaft. This reduces both the bearing distance and the bending moment/load on the bearings, resolving the contradiction between bearing distance and bearing load
3Strength
If expensive materials like carbon steel or molybdenum steel are used, then the strength is ensured, but the cost increases with increased drive shaft length
Solution Approach 1:
The nested bearing arrangement enables a shorter drive shaft design. This reduction in length decreases the material quantity required, lowering both material cost and manufacturing cost while maintaining sufficient strength through optimized structural design
Solution Approach 2:
The invention changes the spatial parameters of the bearing arrangement, which indirectly optimizes the drive shaft length parameter. This parameter optimization reduces material consumption and manufacturing cost while maintaining the required strength through proper structural design
Data Source
Figure 1
Figure 2
Figure 3
AI summary
In a screw compressor including first and second bearings (61, 66) which support a drive shaft (21), the first bearing (61) is disposed adjacent to the screw rotor (40) in an axial direction such that at least a portion of the first bearing (61) is disposed inside the screw rotor (40).