Compressor Shaft Load Compensation via Non-Uniform Stator Coil Density
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Solution Overview
Problem
Conventional compressors in heat pump systems experience inhomogeneous load distribution, leading to reduced efficiency and shorter service life due to uneven forces acting on the shaft and housing, particularly at the fluid outlet, which existing solutions attempt to address by modifying the electric motor winding or structure at increased cost and complexity.
Innovation Solution
A compressor design with an electric drive where coils are densely arranged in the circular sector containing the fluid outlet, providing a higher proportion of torque transmission in this area to compensate for bending loads, allowing for a more homogeneous load distribution without significant structural changes, using a brushless DC motor and adjusting coil density based on pressure increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If coils are uniformly arranged around the compressor circumference, then the manufacturing is simple and cost-effective, but the load distribution on the shaft and housing becomes inhomogeneous, reducing efficiency and service life
Solution Approach 1:
The patent applies local quality by arranging coils with non-uniform density around the compressor circumference. Specifically, the coil density varies in different angular sectors, with higher density in sectors where the shaft experiences greater bending loads. This localized variation in coil arrangement compensates for the inhomogeneous load distribution, reducing peak stresses on the shaft and housing without requiring complete structural redesign.
2Reliability
If existing solutions modify the electric motor winding or structure to compensate for load imbalance, then the load distribution improves, but the manufacturing complexity and costs increase significantly
Solution Approach 1:
The patent changes the parameter of coil arrangement density around the compressor circumference. Instead of uniform distribution, the coil density is varied as a function of angular position, with higher density in regions corresponding to greater shaft bending loads. This parameter change directly addresses the load imbalance problem while maintaining the same basic compressor structure, avoiding complex modifications to the motor winding or overall architecture.
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 design enhances mechanical stability and efficiency by evenly distributing loads across the compressor, extending its service life while minimizing complexity and manufacturing costs, suitable for rotary piston and multi-cell compressors.
Implementation Method 1
several coils are arranged concentrically around a shaft on a stator, and a corresponding number of permanent magnets or coils are located on a rotor. During operation, for example, coils arranged on the stator can be energized with an electric current such that the resulting magnetic field interacts with the permanent magnets on the rotor, thereby transmitting torque to the rotor and generating a rotary motion.
Data Source
Figure 1
AI summary
The compressor (1) proposed here for a heat pump circuit has an electric drive configured such that an increased torque is transmitted in the region of a fluid outlet (3) of the compressor (1). Thus, compared to a homogeneous torque application to the shaft of the compressor (1) distributed evenly around the circumference, a larger proportion of the total torque to be transmitted can be introduced in the region of the fluid outlet (3) of the compressor (1). Advantageously, for example, a bending stress on the shaft caused by the increased load in the region of the fluid outlet (3) by the drive can be compensated for.