Cantilever type motor rotor for direct connection centrifugal compressor and direct connection centrifugal compressor

Abstract

The invention discloses a cantilever type motor rotor for a direct connection centrifugal compressor. An impeller mounting part, a front bearing mounting part, a rotor iron core mounting part and a rear bearing mounting part are formed on the rotor sequentially in an axial direction, wherein a rotor iron core is mounted on the rotor iron core mounting part; the external diameter of the rotor iron core is D, and the length of the rotor iron core is L3; and a range of a ratio D / L3 of the external diameter of the rotor iron core to the axial length of the rotor iron core is 0.25-0.35. The invention further discloses the direct connection centrifugal compressor provided with the motor rotor structure. According to the centrifugal compressor, a motor is adopted to drive an impeller to rotate directly; a speed-increasing gearbox is removed; the centrifugal compressor has the advantages of high rated efficiency, small size, light weight and high energy efficiency; a rotating shaft structure is optimized; and the compressor can keep lower vibration at a high rotating speed.

Description

technical field [0001] The invention relates to a compressor used in the field of air conditioning, in particular to a high-speed (6000 rpm or more) centrifugal compressor with a direct-coupled shaft and a motor rotor thereof. Background technique [0002] Existing centrifugal compressors in the field of air-conditioning usually use fixed-frequency AC motors or variable-frequency AC motors. The speed is increased to the design speed through the speed-increasing gear, and the impeller is driven to rotate to do work on the incoming gas, thereby increasing the gas pressure. This conventional compressor structure has the following deficiencies: (1) Due to the intermediate gear speed increase box, the mechanical loss of the compressor is increased, thereby increasing the power consumption of the compressor and affecting the performance of the unit; (2) the existence of the gear box The shape and structure of the compressor are greatly increased, making the box appear bulky and he...

AI Technical Summary

Problems solved by technology

This conventional compressor structure has the following deficiencies: (1) Due to the intermediate gear speed increase box, the mechanical loss of the compressor is increased, thereby increasing the power consumption of the compressor and affecting the performance of the unit; (2) the existence of the gear box The shape and structure of the compressor are greatly increased, making the box appear bulky and heavy, and the cost also increases; (3) Due to the high speed of the centrifugal compressor, the noise during the gear speed-up process is very loud, so the noise of conventional centrifuges is common It is about 93 decibels, which requires additional sound insulation measures in engineering applications, resulting in increased engineering costs

[0003] In addition, there are also direct-coupled centrifugal compressors that directly connect the impeller of the compressor to the shaft of the motor. In this form of compressor, since the impeller of the compressor and the motor share a shaft, the vibrations of the two are superimposed on the shaft, causing the compressor to The vibration increases, especially at high speeds

In addition, due to the omission of the speed-up gear, the effect of the original speed-up gear against axial force also disappears, and the axial force generated by the impeller is difficult to be balanced, which further aggravates the vibration of the compressor

In order to suppress the vibration of the direct-coupled centrifugal compressor at high speed, the existing means are usually to improve the positioning device of its rotor, such as the use of magnetic suspension bearings and axial thrust bearings, etc., but the rotor is the main movement in the compressor components, which play a key role in the vibration performance of the compressor, only by improving its positioning device without optimizing the main structural dimensions of the rotor, the improvement in the vibration performance obtained is very limited

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