Coupling common problems and solutions

    Common problems and solutions of couplings:

    Balance class

(1) The balance level of any coupling assembly is determined according to the square root value of the possible peak value of the eccentricity of the center of gravity position between the inertial main axis of the coupling and the rotation axis. Its unbalance is expressed in microns.

(2) The potential unbalance factors of the coupling components have been introduced before, and the steps to determine the balance level of various types of coupling components and calculate the balance are shown in the calculation example.

(3) Standard grading table of coupling balance grades The following table shows the offset of the main axis of inertia to the rotation axis at the position of the balance surface, expressed as the peak value of the root mean square micrometer, and its value is the coupling calculated by the AGMA method. Displacement of the main axis of inertia on the balance surface (root mean square) of the coupling balance standard level

     balance problem

Due to various reasons, the center of mass or inertial main shaft of the coupling does not coincide with its rotation axis, and the phenomenon of unbalanced centrifugal inertial force, centrifugal inertial couple force and dynamic deflection (mode shape) will be generated during operation, which is called the unbalance of the rotor. This unbalance phenomenon will inevitably cause the vibration of the shaft system, thereby affecting the normal operation and service life of the machine, so it must be paid attention to. The degree of unbalance (unbalance amount U) is usually expressed by the product mr of the mass m of the rotor and the distance r from the center of mass to the rotor axis of rotation, which is called the mass-diameter product. It is also expressed by the mass-diameter product per unit mass, called the eccentricity e (not the eccentricity in the geometric sense.) The mass-diameter product mr is a relative quantity related to the mass of the rotor, while the eccentricity e is a relative quantity related to the mass of the rotor. the full amount. The former is more intuitive and is often used for the balancing operation of a specific given rotor. The latter is used to measure the pros and cons of rotor balance or to detect the balance accuracy. The balance level standard of the coupling is evaluated according to e. For the flexible rotor, the eccentricity of the mode shape (the nth order mode) is used as en=Un/mn, where Un and mn are the nth order mode and the modal mass, respectively.

In order to correct or minimize the unbalance of the coupling, the appropriate balance level should be selected according to the needs, and after the product is manufactured and installed on the machine, on the balance (correction) plane specified by the coupling, through A method of adding or subtracting the appropriate quality to achieve the balance level requirement. This process is called balance correction, or balance for short.