Scroll Compressor Discharge Brush Grounding and Cooling Layout
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Solution Overview
Problem
In scroll compressors with integrated motors, electrolytic corrosion in bearings occurs due to shaft voltage, leading to reduced bearing life and increased compressor size, as existing solutions require conduction between the fan cover and brush holder to ground the motor, which enlarges the compressor.
Innovation Solution
A scroll compressor design featuring a discharge brush fixed to the end bracket, which contacts the rotary shaft to discharge current and reduce shaft voltage, while a suction-type cooling fan is positioned apart from the end bracket to allow air suction and generate cooling wind, thereby reducing the compressor's size and preventing electrolytic corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a brush in a brush holder attached to a fan cover is used to contact the radial fan and reduce shaft voltage, then shaft voltage is reduced, but the entire size of the compressor increases due to required conduction between fan cover and case housing
Solution Approach 1:
The invention extracts the grounding function from the fan cover assembly and relocates it to the end bracket. The brush holder is detached from the fan cover and reattached to the end bracket, which is already grounded to the case housing. This separation eliminates the need for additional conduction paths through the fan cover, maintaining shaft voltage reduction while avoiding compressor size increase.
Solution Approach 2:
The end bracket serves as an intermediary component that provides the grounding function. Instead of requiring the fan cover to conduct electricity to ground, the end bracket acts as a mediator that is already electrically connected to the case housing, thereby grounding the brush and reducing shaft voltage without requiring modifications to the fan cover assembly.
2Volume of stationary object
If the cooling fan is positioned close to the end bracket for compact design, then space is saved, but air suction capability and cooling efficiency are reduced
Solution Approach 1:
The invention optimizes the spatial arrangement by positioning the cooling fan in a specific dimensional relationship with the end bracket. The fan is located at a predetermined distance that provides optimal airflow path, allowing it to effectively suction air from the motor casing and cool the motor while maintaining a compact overall compressor design. This dimensional optimization balances space savings with cooling efficiency.
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 design effectively reduces shaft voltage, prevents electrolytic corrosion, and achieves space savings by grounding the discharge brush and optimizing the compressor's layout, improving maintainability and motor efficiency.
Implementation Method 1
a discharge brush which is fixed to the end bracket facing the cooling fan and one end of which is in contact with the rotary shaft
Implementation Method 2
a suction type cooling fan which is fixed to one end portion of the rotary shaft while being apart by a clearance from the end bracket, and which suctions outside air through a suction port provided in an end surface of a fan cover, the end surface facing the end bracket, and generates cooling wind for cooling the fixed scroll or the orbiting scroll
Data Source
AI summary
A scroll compressor includes a rotor, a stator, a rotary shaft, an end bracket, an orbiting scroll, a fixed scroll, a suction type cooling fan, and a discharge brush. The discharge brush is fixed to the end bracket facing the cooling fan by a fixing member attached in a radial direction relative to the rotary shaft, and one end of which is in contact with the rotary shaft, in a space secured by the clearance.