Oilless Compressor Motor Cooling Jacket Design
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Solution Overview
Problem
Oilless compressors face challenges in miniaturization and cooling efficiency due to the need for a dedicated oil sump and refrigerant system, which increases size and complexity, and limits the miniaturization of the gear casing area.
Innovation Solution
An oilless compressor design that uses a cooling jacket as both a lubricating oil sump and a cooling mechanism for the electric motor, eliminating the need for a separate oil sump in the gear casing and allowing for efficient lubrication and cooling with the same lubricating oil, thereby reducing the compressor's size and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a liquid-cooled electric motor system with dedicated refrigerant and cooling path is provided, then the cooling performance of the electric motor is improved, but the size and configuration complexity of the compressor increases
Solution Approach 1:
The lubricating oil is made to serve dual functions: both as a lubricant for machine elements (bearings, gears) and as a coolant for the electric motor. The lubricating oil circulates through the motor housing, absorbing heat from the motor, and then passes through a heat exchanger for cooling before being recirculated. This eliminates the need for a separate dedicated refrigerant system while achieving effective motor cooling.
Solution Approach 2:
The cooling function for the electric motor is merged with the existing lubricating oil circulation system. The lubricating oil tank, pump, and heat exchanger that were originally designed solely for lubrication are extended to also perform cooling duties, combining two functions into one integrated system.
2Temperature
If a big radiating fin or large cooling fan is provided to improve cooling capacity of air-cooled electric motor, then the cooling performance is improved, but the size of the compressor increases
Solution Approach 1:
The patent replaces air cooling (pneumatic approach) with liquid cooling using lubricating oil. The hydraulic/liquid cooling system allows for more efficient heat transfer in a compact form factor, eliminating the need for large radiating fins or high-speed cooling fans that would increase compressor size.
Solution Approach 2:
The lubricating oil serves dual purposes as both lubricant and coolant, eliminating the need for separate cooling components that would increase the compressor's volume. The same fluid that lubricates moving parts also cools the electric motor through circulation and heat exchange.
3Reliability
If room for an oil sump is secured in the gear casing, then the lubrication function is ensured, but the size of the gear casing and overall compressor increases
Solution Approach 1:
The lubricating oil tank is designed to serve dual functions: as the oil sump for maintaining lubrication of machine elements and as the cooling system for the electric motor. This integrated design eliminates the need for separate oil reservoir space in the gear casing, reducing overall compressor size while maintaining adequate lubrication capacity.
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 enables efficient miniaturization of the compressor, improves the cooling performance of the electric motor, and simplifies the assembly and cost aspects while maintaining effective lubrication of machine elements.
Implementation Method 1
a cooling jacket for cooling an electric motor is used as an oil sump
Implementation Method 2
lubricating oil is circulated into the cooling jacket
Implementation Method 3
lubricating a machine element in the compressor
Data Source
Figure 1(a)~1(b)
Figure 2(a)~2(b)
Figure 3
AI summary
Size reduction of a compressor and cooling of an electric motor are effectively achieved. An oilless compressor, having: a compressor main body that has a rotor for compressing air, a rotor shaft for supporting the rotor, and a bearing for rotatably supporting the rotor shaft; an electric motor for producing drive force for driving the compressor main body; at least one gear for transmitting drive force to the rotor shaft; a lubricating oil pipe for conveying lubricating oil to the bearing and/or the gear; and an oil pump for pressure-feeding the lubricating oil; wherein the electric motor has, in the external peripheral direction of an armature, a cooling jacket for channeling the lubricating oil to an internal flow channel to cool the armature of the electric motor, and the lubricating oil circulates through the cooling jacket and the lubricating oil pipe.