High-speed motor bearings are equipped with doorways
The bearing is a key component to support the normal operation of the motor. In addition to the manufacturing process control, the design and configuration of the motor bearing is very important. For example, the vertical motor and the horizontal motor should use different bearing configurations. The motors with different speed requirements should also be different. Bearing. In the chat with a friend, it has unique insights on the matching of bearings, so Ms. Participation is summarized and shared with you.
Horizontal motor bearing configuration
A ball bearing and a column bearing should be used as far as possible at both ends of the horizontal motor. At present, the domestically produced 2-pole small and medium-sized motors mostly use two ball bearings, although some manufacturers have adjusted the tolerance of the bearing indoor diameter to the direction of the clearance fit, in order to alleviate the disadvantages of the ball being squeezed after the bearing is heated. However, since the expansion coefficient of the bearing shell is larger than that of the cast iron part bearing the bearing chamber, the end cover or the bearing sleeve, and the temperature at the bearing jacket is also high, the bearing jacket can be axially located in the bearing chamber at room temperature. Sliding a little bit, but the bearing may not be able to move after the bearing is heated. This is the main reason for the short bearing life and easy heating when using two ball bearings. After the temperature rise test, the motor with two ball bearings stops the temperature rise, and sometimes the bearing of the second drive motor burns out. The reason is that the ball bearing can not bear the thermal expansion and contraction of the rotor. It can not creep in the bearing chamber, so that the ball is subjected to a large axial force.
If you choose a ball bearing and a column bearing, the above problems can be avoided. A better motor factory in the same place will change the high-voltage motor of the 2 pole of the H560 base to a ball bearing and a column bearing. The post-operation effect is very good. Except for replacing bearings in the normal service cycle, there is never a malfunction during normal operation. Moreover, the temperature measured at the bearing is only 20 °C. This is the first successful case in which the traditional 2-pole motor has been changed from a ball bearing to a ball bearing and a column bearing. It has been gradually promoted on explosion-proof motors.
In order to solve the problem of heat and noise of the limit speed after replacing the ball bearing with the column bearing, a light series column bearing can be used, and it is placed on the outer fan end, the cooling condition is good, and the bearing noise can be overwhelmed by the fan noise. If the 2-pole motor with large power is used, the bearing type is large, and the light series column bearing is also difficult to meet the requirements of the limit speed. It is also possible to change the bearing grease to thin oil.
Vertical motor bearing configuration
When a vertical motor is used in a petrochemical system to drive a belt pump, the multi-stage belt pump has an instantaneous upward axial force at the start, plus transportation requirements, and in order to eliminate the thermal expansion of the rotor to the bearing belt. The damage, vertical drum with pump motor (both 2-pole or 4-pole), the upper bearing of the motor should use two pairs of single-row radial thrust ball bearings, the lower bearing column bearings, still choose light The series is suitable. In order to prevent damage to the thrust ball bearing, the two pairs of bearings should have a pre-added axial force applied to the bearing casing. The force is such that the bearing is not damaged by the reverse axial force from the shaft extension end to the non-load end when transporting and starting.
Bearing specifications and model selection
For 2-pole motors, light series bearings should be used as much as possible; motors with 4 or more poles that are not positive or negative should be selected for series bearings; positive and reverse low-speed motors should be selected for heavy series bearings. A ball bearing and a column bearing should be selected for light, medium and heavy. The 2-pole motor should be placed on the shaft end.
In recent years, some motor factories have used large-gear ball bearings on two-pole motors that use two ball bearings. This is also a measure to alleviate the bearing damage caused by the reduction of the bearing heat during operation. However, the mechanical noise of large clearance bearings also increases. If a ball bearing and a column bearing are selected, the tolerance of the bearing chamber can be selected to eliminate the above disadvantages.
