时间：2013-11-20 09:23　作者：admin　点击： 次

The search of the coupling is one of the important tasks of the machine installation. The purpose of the alignment is to make the center lines of the driving shaft and the driven shaft on the same straight line when the machine is working. The accuracy of the alignment is related to whether the machine can Normal operation is especially important for high-speed machines.It is difficult to achieve absolute accuracy of the two-axis alignment, and it is even more difficult to maintain accurate alignment at all times for the continuous operation of the machine.The uneven thermal expansion of various parts, the deflection of the shaft, the uneven wear of the bearing, the displacement of the machine and the uneven sinking of the foundation, etc., are all reasons why it is difficult to maintain the shaft alignment.Therefore, when designing the machine, it is stipulated that there is an allowable deviation value for the center of the two shafts, which is also required when installing the coupling. From the assembly point of view, as long as the coupling can ensure the safe and reliable transmission of torque, the allowable deviation of the two shaft centers The larger the value, the easier it is to meet the requirements during installation.However, from the perspective of installation quality, the smaller the deviation of the centerline of the two shafts, the more accurate the alignment, the better the machine's operation, and the longer the service life.Therefore, the allowable deviation of the alignment of the two shafts when the coupling is installed cannot be regarded as the margin left by the installer's hasty construction.
Through the alignment of the coupling, each axis of the unit can meet the requirements of coaxiality, so that after the unit is installed and overhauled, each axis can still maintain a reasonable alignment state during operation, so as to ensure that the machine can be long-term, stable and stable. Normal continuous operation.
The alignment of the unit coupling occupies a very important position in the machine installation process and is the most critical process.
The centering deviation between the active shaft (motor or steam turbine) and the driven shaft (pump or compressor) of the unit is the deviation of the relative position of the two shafts in the cold state, which is reflected in the adjacent two half couplings of the shaft end. Therefore, the alignment of the shaft is mostly achieved by detecting the alignment of the coupling, so the alignment of the two shafts is represented by the alignment of the coupling.
At present, the methods of coupling alignment are roughly divided into two categories:
(XNUMX) Direct measurement method: generally use a straightedge, square or feeler gauge to measure the radial deviation of the outer edge of the two halves of the coupling and the axial gap at both ends, and use this method to align , The error is large, the accuracy is low, and it is mostly used for the unit with low speed and low alignment accuracy requirements.
(XNUMX) Use the aligning tool measurement method, which is a method commonly used in the safety and maintenance of the unit. Generally, the reference axis (active axis) is used as the axis to be on the end faces of the two shafts, and the axis is inclined. And the deviation of the radial displacement, so as to determine the adjustment amount and adjustment direction at each foot of the driven machine by the detection value, and by changing the thickness of the gasket, the unit centering condition is within the allowable deviation range.
Because of the large error, the direct measurement method is easy to operate and there are not many use occasions, so I will not describe it here for reference only.