Compressor Motor Oil Circulation for Long-Term Winding Insulation
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Solution Overview
Problem
Conventional ammonia refrigerant devices face issues with insulation capability degradation over time due to the use of fluoro resin and complex lubricant distribution systems, leading to increased power requirements and installation restrictions.
Innovation Solution
A refrigerating device with a compressor driven by a motor, featuring an oil circulation system that supplies oil from the refrigerant circulation flow passage to the motor casing, ensuring oil distribution between windings and maintaining insulation capability, along with a control valve for adjusting oil supply and using a fluoro resin with permeability for ammonia gas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lubricant storage structure is added to submerge windings, then insulation is improved, but device complexity and cost increase
Solution Approach 1:
The patent makes the lubricant system serve multiple functions simultaneously: it provides lubrication for moving parts, cooling for the motor, and insulation protection for the windings. This eliminates the need for separate insulation structures and simplifies the overall device design.
Solution Approach 2:
The lubricant automatically distributes itself to where it is needed through the pressure differential created by the compressor's operation. The oil circulates through the system and naturally reaches the motor windings without requiring complex pumping or distribution mechanisms.
2Reliability
If vertically standing motor arrangement is used, then lubricant delivery is improved, but installation flexibility is restricted
Solution Approach 1:
The patent creates a dynamic lubricant circulation system that adapts to different installation orientations. The oil circulation is driven by pressure differentials and gravitational forces that work effectively regardless of the motor's vertical or horizontal position, allowing flexible installation arrangements.
Solution Approach 2:
The patent designs the lubricant circulation system to maintain effective oil delivery under various gravitational conditions. By ensuring that oil can reach the windings through pressure-driven flow and natural circulation paths that work in any orientation, the system achieves equipotential performance regardless of installation position.
3Reliability
If motor rotates at high speed in oil, then lubrication is improved, but agitating loss increases and power requirement increases
Solution Approach 1:
The patent applies lubrication locally where it is most needed - at the bearing contacts and shaft seal interfaces - rather than requiring the entire motor to rotate in a bath of oil. This localized lubrication approach minimizes agitating losses while maintaining effective lubrication at critical points.
Solution Approach 2:
The patent uses a partial immersion approach where only specific components are lubricated by oil, rather than submerging the entire motor. This provides sufficient lubrication for the moving parts while minimizing the energy loss associated with agitating large volumes of oil.
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 maintains the insulation capability of the motor over time, increases reliability, and reduces the complexity and cost of the lubricant system, while allowing for flexible oil supply and distribution, thus preventing performance decreases.
Implementation Method 1
an internal pressure of the motor casing is lower than a pressure in an oil sump in the refrigerant circulation flow passage
Implementation Method 2
even if the fluoro resin providing such excellent chemical resistance is used along with the ammonia gas, and the appearance of the fluoro resin is not damaged, an insulation capability of the motor decreases with the elapse of time
Data Source
AI summary
In a refrigerating device comprising: a compressor that is driven by a motor; a refrigerant circulation flow passage that includes an oil separator/collector, a condenser, an expansion valve, and an evaporator; and an oil flow passage that conducts oil in the oil separator/collector to a bearing of the compressor, an oil supply opening is provided for a motor casing that stores the motor, an oil supply line for supplying oil from an oil sump of the refrigerant circulation flow passage on the discharge side of the compressor to the oil supply opening is provided, oil is supplied to the oil supply opening through the oil supply line, and oil is distributed across surfaces of windings of the motor. And an internal pressure of the motor casing is lower than a pressure in the oil sump in the refrigerant circulation flow passage on the discharge side of the compressor, consequently oil is easily distributed across the entire motor casing. In such a refrigerating device, an insulation capability of the motor does not decrease with the elapse of long time.