Screw Compressor Thrust Bearing Balance Mechanism
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Solution Overview
Problem
Conventional screw compressors with balance piston structures face mechanical loss and reduced service life due to increased oil stirring at higher speeds and reliance on rolling bearings, which are difficult to extend.
Innovation Solution
A compressor design incorporating a screw rotor with radial and thrust bearings, a balance mechanism using a slide bearing with lubricant, and a control unit to adjust working fluid pressure and lubricant flow, reducing thrust loads and mechanical losses, and extending the service life of bearings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a balance piston structure is used in a screw compressor, then the thrust load on the bearing is reduced, but mechanical loss increases due to oil stirring by the piston at high speeds
Solution Approach 1:
The patent introduces a thrust plate as an intermediary component between the balance piston and the thrust bearing. The thrust plate transfers the balancing force from the piston to the bearing while being isolated from direct contact with the working fluid, thereby eliminating the oil stirring loss that would occur if the piston directly supported the bearing load in the working fluid environment.
2Ease of operation
If rolling bearings are used to support the rotor shaft, then the compressor can operate smoothly, but the service life cannot be extended
Solution Approach 1:
The patent employs slide bearings instead of rolling bearings, accepting that slide bearings have shorter service life but can be easily replaced. The design prioritizes operational smoothness and ease of maintenance over extended bearing life, allowing for simple bearing replacement without complex assembly disassembly, thus achieving cost-effective operational reliability.
3Productivity
If the rotor shaft rotational speed is increased to improve productivity, then output increases, but mechanical loss from oil stirring increases
Solution Approach 1:
The thrust plate serves as a mediator that decouples the rotor shaft from direct contact with the working fluid during thrust loading. This intermediary structure allows the rotor shaft to rotate at high speeds without the working fluid stirring the oil in the balance piston area, thereby maintaining high productivity while reducing mechanical loss from fluid agitation.
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 reduces power loss from fluid stirring, adapts the balance piston unit for high-speed operation, and extends the service life of both thrust and radial bearings by minimizing unnecessary pressing forces and overloads.
Implementation Method 1
a slide bearing that presses the thrust plate via a lubricant between the slide bearing and the thrust plate
Implementation Method 2
a balance piston unit that presses the slide bearing toward the thrust plate by a pressure of a working fluid
Data Source
AI summary
A screw compressor includes a screw rotor including a rotor shaft, a radial bearing, a thrust plate, a balance mechanism, which is a slide bearing, a lubrication oil supply flow passage for supplying a lubrication oil, and a working fluid supply flow passage for supplying a working fluid for pressing the balance mechanism toward the thrust plate so that a reverse thrust load acts on the thrust plate.