Refrigeration compressor having an outer-rotor type motor with the stator fixed to a member fixed to a cylinder block
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Solution Overview
Problem
Existing closed compressors require high accuracy in manufacturing and assembly to maintain coaxiality and clearance between components, leading to increased costs and reduced efficiency due to potential twisting of the crankshaft and uneven clearances, which affects motor efficiency.
Innovation Solution
A closed compressor configuration where the stator is fixed to a stator fixing member, which is attached to the compression element, and the auxiliary bearing is separate and coaxial to the main bearing, allowing for accurate clearance and coaxiality without requiring highly accurate component processing, using a stator fixing member and screwing for assembly, and optionally employing a spherical bearing for reduced twisting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If high accuracy manufacturing and assembly are performed to maintain coaxiality and clearance between components, then motor efficiency is improved, but manufacturing costs increase
Solution Approach 1:
A dedicated bearing support structure is introduced as an intermediary component that specifically supports the auxiliary bearing. This structure includes a bearing support portion with a through-hole that receives the auxiliary bearing, ensuring precise positioning and coaxiality without requiring high-precision manufacturing of all surrounding components. The bearing support structure acts as a mediator that isolates the precision requirement to only the critical bearing interface.
Solution Approach 2:
The compressor body is segmented into functional regions: a compression element region and a motor region. The motor region includes a stator and rotor with precise clearance, while the bearing support structure provides localized precision support. This segmentation allows different parts to have different precision requirements, reducing overall manufacturing costs while maintaining motor efficiency.
2Reliability
If high accuracy assembly is performed to prevent crankshaft twisting, then reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The bearing support structure serves as a mediator that provides a stable, precision-engineered interface for the auxiliary bearing. By concentrating the precision requirements in this dedicated support structure rather than distributing them across multiple components, the assembly process becomes simpler and more reliable. The support structure ensures the auxiliary bearing maintains correct position and orientation, preventing crankshaft twisting.
3Reliability
If clearance between rotor and stator is widened to avoid contact, then reliability is improved, but motor efficiency decreases
Solution Approach 1:
The bearing support structure with its precisely dimensioned through-hole acts as an intermediary that ensures even clearance between the rotor and stator. The auxiliary bearing, supported by this structure, provides a stable reference that maintains consistent radial clearance without requiring the clearance to be excessively large for safety margins.
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 reduces the occurrence of crankshaft twisting, narrows the clearance between the rotor and stator, enhances motor efficiency, and lowers processing costs while maintaining reliability, resulting in improved efficiency and reduced power consumption for the refrigeration device.
Implementation Method 1
electric motor 3 is an outer-rotor type motor and is configured to include stator 9 and rotor 10
Data Source
AI summary
A stator of an outer-rotor type motor is fixed to a stator fixing member, and the stator fixing member is fixed to a member (cylinder block) of a compression element, which has a main bearing. Further, an auxiliary bearing is configured to be separate from the stator fixing member and is fixed to the stator fixing member. In this manner, it is possible to fix the stator fixing member to the member of the compression element in a state in which an even clearance is formed between an inner circumference of a rotor and an outer circumference of the stator, and it is possible to fix the auxiliary bearing to the stator fixing member in a state in which the auxiliary bearing is reliably coaxial to the main bearing.