There are many reasons for mechanical vibration, among which the vibration of rotating parts is the most direct because of its balance problem.However, this does not mean that the rotor can solve all vibration problems after being well balanced on the balancing machine.The problem of unbalance of the rotor is that the center of gravity of the rotor deviates from its rotational geometric center line.When the rotor rotates, the centrifugal force caused by it rotates with the rotor, thus causing the vibration of the rotor and the installation foundation of the rotor (such as: bearing seat, frame, chassis, body, etc.).Other related process issues are discussed below.
1, the dynamic balancing machine itself process problems
When balancing with high precision, the influence of universal coupling and key should be considered.The influence of auxiliary mass such as cursor on the final balance precision should also be considered.When the unbalance caused by these related joints is close to or even higher than the user's standard rotor balance precision, the unbalance displayed by the dynamic balancing machine is not reliable.For the dynamic balancing machine driven by universal coupling, the balance precision of universal coupling should also be maintained regularly.
When the process shaft is selected for balance, the circular runout of the process shaft shall not be higher than the precision index e (eccentricity) of the rotor balance, or else the rotation 1800 high-precision balance must be carried out.Or scrap the process shaft.Another, the construction of the process shaft and the actual installation of the rotor shaft should be made to be the same or similar as far as possible to ensure the same mass distribution as the actual installation.
2, the rotor process
Dynamic balancing machine users should choose as far as possible to balance the real installation of the rotor, and ensure its rigidity.Select process shaft for balance, there are process shaft and rotor actual installation shaft deviation, for example, the rotor in the process shaft and the actual shaft is not the same way of installation, keyway structure, process shaft and the actual shaft each have jitter, these elements are caused by uneven balance of change.
When selecting the process shaft for balance, it is necessary to ensure the rotor installation hole size precision and shape tolerance precision, and so on: with large gap, hole ellipse or taper deviation, roughness is absolutely not allowed.
In addition, the rigidity of the rotor must be ensured.If the rotor has sliding splines, movable blocks, swinging knife blocks and other similar structures, such a rotor will never achieve the ideal balance precision.
3, the actual installation of the rotor process
Rotor in the dynamic balancing machine has reached the standard balance precision, in the actual installation and operation of the rotor, if some elements in the actual installation process did not go to seriously consider, will also lead to the change of the balance precision, and cause a certain degree of vibration.
The first is the jitter of the actual mounting shaft, which is crucial.Because of the imbalance of the rotor, the center of gravity of the rotor deviates from its rotational geometric center line.As the rotor rotates, the centrifugal force caused by it rotates with the rotor, thus causing the rotor and the mounting foundation of the rotor to vibrate.The well-balanced rotor is installed on the actual installation shaft with eccentricity, which of course will cause the vibration of the rotor and equipment.In addition, other coaxial parts and components with the rotor will also cause the vibration of the rotor and equipment, such as belt pulley, coupling, motor rotor, their balance precision will also be involved in the vibration of the equipment with the rotor.
4, other problems my company's technical staff in the after-sales service found that there is a mobile balance machine user in the production process of its products, do not pay attention to grasp the early manufacturing quality of its products, and its rotor operation performance completely depends on the rotor dynamic balance process, is also very not serious.For example, the product design does not consider the dynamic balance of the process;The basic parts of the product (such as supports, etc.) cut corners and even have serious defects;The appearance end face of fan rotor or other welded structure rotor is too jitter;The mass distribution of cast rotor is too uneven and the deviation is too large.The mounting hole precision and roughness of rotor are too low.There are serious non-rigid factors in the internal structure of the rotor (such as: welding leakage, rivet loosening, etc.);The surface roughness and precision of the process shaft are too low;The precision and roughness of rotor mounting shaft are too low.
All of these factors are responsible for the reduction of balance precision or even the failure of balance.
In addition, dynamic balancing machine belongs to instrument equipment testing machine products.The rough operation of the dynamic balancing machine (such as: on the balance machine for welding, sanding, etc.) will directly harm the performance of the dynamic balancing machine and service life, resulting in balance failure, ten million special attention.