 ## Common problems with couplings

##### Date:Jul 25, 2018

(1) The balance level of any one of the coupling assemblies is determined according to the square root value and the square root value of the maximum possible value of the eccentricity of the center of gravity between the main axis of the coupling and the rotation axis. The amount of imbalance is expressed in microns. (2) The potential imbalance factors of the coupling assembly are described above. The steps for determining the balance level and calculation balance of various types of coupling assemblies are shown in the calculation examples. (3) Standard grading table of coupling balance level Table below, at the equilibrium surface position, the maximum deviation of the inertial main axis from the rotation axis is expressed by the maximum root mean square micrometer, and the value is the coupling calculated by the AGMA method. Balance of the standard grade coupling balance level The maximum displacement of the inertial main axis on the balance surface (root mean square) Coupling balance level The maximum displacement of the inertial main axis on the balance surface (root mean square)

Balance problem

For various reasons, the coupling does not coincide with its center of mass or inertia spindle and its axis of rotation. During operation, it will produce unbalanced centrifugal inertia force, centrifugal inertia force and dynamic deflection (vibration shape), which is called rotor imbalance. Phenomenon, this imbalance will inevitably cause vibration of the shafting, which will affect the normal operation and service life of the machine, so it must be taken seriously. The degree of unbalance (unbalance amount U) is usually expressed by the mass mr of the mass m of the rotor and the distance r from the centroid to the rotor axis, which is called the mass diameter product. Also expressed by the mass mass product of unit mass, called eccentricity e (not geometrically eccentric.) The mass diameter product mr is a relative quantity related to the rotor mass, and the eccentricity e is a rotor quality. The absolute amount. The former is more intuitive and is often used for the balancing operation of a given rotor. The latter is used to measure the balance of the rotor balance or the accuracy of the detection balance. The balance level standard of the coupling is evaluated by e. For the flexible rotor, the eccentricity (nth-order mode) en=Un/mn is used, and Un and mn are the n-th mode and the mode-mode quality, respectively.

In order to correct or minimize the unbalance of the coupling, the appropriate balance level should be selected as needed, and after the product is manufactured and installed on the machine, pass through the balance (correction) plane specified by the coupling. Increase or decrease the appropriate quality method to achieve a balance level requirement. This process is called balance correction, referred to as balance.

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