Time：2021.02.11 Source：Roller Bearings Suppliers
Overview of crane pulley bearing
Block and tackle is the important component part of the crane, but also an important component of crane hoisting, generally, the pulley block made by rolling bearing, pulley, slide shaft, rolling bearing bushing, the structure under radial force is superior to bear axial force. Often appears in this structure in the use of the rolling bearing ring, support ring, casing damage caused pulley can not rotate, wire rope wear serious, so can't normal construction.
Rolling bearing installed inside a pulley, using the lifting arm on the pulley shaft installed in the section, using a spacer between pulley and roller keep proper clearance, non-interference in each other to ensure the work. If the bearing damage will directly affect the normal crane hoisting
Crane pulley bearing damage cause analysis
1. The crane overload
Crane has a load table, namely the crane construction operations must be according to the load table annotation of load-lifting heavy objects, it is strictly prohibited by more than the limit load table construction operation. Cranes are left when the design safety factor, but is common in domestic construction crane overload current situation, the lead to reserve safety coefficient is relatively small, even offset reserve safety coefficient. This crane local agencies will likely damage and failure, lifting weight overload, directly cause lifting pulley parts bearing load increase, close to or beyond the stress range, this is the most direct reason for bearing damage. Need WSBC 22214 CC/W33, Click here to learn more.
2. Wire rope and pulley wear problems
Directly on the crane lifting pulley winding wire rope, wire rope for full weight lifting objects, so the object passed to directly by wire rope and pulley bearing weight. Lifting pulley block is formed by a pulley, two bearings, two bearing installed on both side lifting pulley, if the rope pulley groove center and pulleys itself is not in the same plane, as shown in figure pulley analysis diagram 3.Gravity is not evenly distributed on the two bearings, a large and a small, or even a single gravity on the pulley is fully borne by a bearing, bearing large axial force at this time. Due to bearing its own structure determines its ability to withstand radial force is far greater than its ability to bear axial force, so under the action of axial force, bearing retainer is easy to damage, and damage of bearing ball racks, lead to the bearing can not rotate, wire rope and pulley wear problems and eventually, cranes can not work normally.
3. Shaking problem
During the construction of the crane heavy in the air is not stable, there is shaking. Because the shaking can cause uneven bearing load, if the pulley is also in rotation, bearing retainer strength significantly increased, in this case, the construction, bearing retainer is easily damaged, cause the ball around, and bearing retainer completely damaged, finally damage the bearings, affect the construction.
4. Crane design process
In design and selection of bearing pulley, must according to the load, construction conditions, etc., to consider and reserve safety coefficient. If a small safety factor or a great error in the calculation load, leading to a single pulley on gravity to calculate partial moment cause inappropriate selection of bearing, tolerance can't meet the needs of the practical work. In addition to working conditions are not familiar with, the static load working load test not only considers the impact load but also causes the selected bearing does not meet the actual work needs, lead to bearing damage easily, short service life. If the selection of parameters in small bearings, even if there is no overload, pulley quality unqualified weight lifting and stability three conditions, the bearing will be premature damage. Click here to learn more about WSBC 22216-E1.
Engineering construction generally emphasizes timeliness, time is a benefit, crane as a kind of special machinery and equipment, for the construction process of continuous (, uninterrupted, must in view of the above situation is analyzed, in order to solve the problem of premature failure, after analysis, the structure of crane hoisting parts I made some improvements.
Table 1 and increase the overload limit device: according to the load calculation of bearing maximum tolerance, when bearing load force is equal to the rated force to sound an alarm, prompt operation personnel. When bearing load-bearing force beyond the rated load or beyond the safety coefficient, the safety device locks crane operation, under the action of force construction personnel in accordance with the crane load table, and thus the bearing by force, protection of bearings, prolonging the service life of the bearing.
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