Two reasons and three improvement measures for the large vibration of the transmission system of the ball mill

Date: 2019-07-08 Views:

The transmission system is an important part of the ball mill, and the running state of the transmission system directly influences the operation of the whole machine. In the operation of the ball mill, the vibration of the transmission system, the fracture of the anchor bolt, the breakage of the lubricating pipeline and the damage of the bearing can occur. In this paper, the causes and solutions of the problems are shared.

2 m-13 m cement mill (main motor power of 1600 kW) of a cement company adopts the edge transmission mode, and the JDX1000 single-stage gear transmission speed reducer is configured. The transmission system has a large vibration since it is put into operation. After a period of time, the vibration is more severe.

In case of failure to solve effectively, the anchor bolt of pinion bearing pedestal and the anchor bolt of reducer are broken repeatedly due to large long-term vibration, and the lubricating oil pipeline is also broken frequently, and the reducer bearing is easily damaged, which seriously affects the operation safety of the equipment.

During the fault handling, the input and output couplings of the speed reducer are found according to the requirements of the equipment installation specifications. When the ball mill is found, the initial stage of the ball mill is still too large, but it can be kept in operation. If it is not in operation for a week, it will be forced to stop again. Although it has been found for a number of times, the problem cannot be thoroughly solved. This paper analyzes the causes and solutions of the problems.

1. Analysis of vibration reasons of ball mill.

 

1) the installation accuracy of open gear of mill is not enough.


After many measurements in different positions of large gear and pinion, it is found that the radial and axial jump values of large gear meet the requirements, but the deviation of tooth surface clearance and top clearance of large and small gears is large in different positions.

The pinion shaft is checked again to eliminate the bending deformation of the shaft, and the pinion is connected by two sets of locking sleeves on the shaft. it is found that the concentric deviation between the pinion and the gear shaft is too large.

Therefore, it is judged that the bolt fastening of the locking sleeve is not uniform during installation, and the pinion centerline and the centerline of the main shaft form an angle α in the three-dimensional space. See Fig. 1 for concentricity deviation of pinion and gear shaft.

in that proces of the meshing of the pinion and the pinion, the gear is generally not rotate, the circumferential direction of the gear is fixed in a position to adjust the bearing seat of the pinion so as to ensure that the clearance between the tooth top and the tooth side of the pinion gear is in accordance with the installation specification of the equipment, As the acceptance data, the test data which is in accordance with the requirements is found.

However, because the pinion and the gear shaft are different from each other, when the pinion rotates at a certain angle and measures the meshing data of the gear pair again, it will be found that it can not meet the requirements of installation accuracy at all, so it will cause great vibration in the course of operation.

2) the installation foundation of reducer is not stable and reliable enough.


The reducer is a single-stage gear drive reducer, the box width is small (only 950mm), and the total length of the input and output shafts is longer (1980mm), which is more than twice the base of the reducer. The reducer is directly installed on the concrete foundation. Due to the limitation of the oil return shell, the contact area of the bottom surface of the reducer is too small, and only 8 groups of oblique cushion iron are under force.

Affected by installation, it is difficult to guarantee the contact area and force uniformity of inclined cushion iron. When the equipment is running, the reducer is easy to change under the action of lever principle after being vibrated by pinion, and the micro displacement change at the bottom seat is magnified at both ends of the coupling, resulting in a vicious circle of concentric degree decreasing. The installation dimensions of the reducer before improvement are shown in figure 2.

(2) improvement measures

 

1) disassemble and reassemble pinions


The concentricity of the positive and positive pinion and the gear shaft is measured by the dial indicator in the process of tightening the pinion lock sleeve, so that the radial runout value and the end face runout value are ensured to be within 0.10 mm of the installation specification.

2) re-find the tooth surface side gap of the forward open gear


Because the contact surface changes after the pinion is corrected again, the original positioning can not guarantee its accuracy. After ensuring the side gap size of a position according to the requirements, the whole cycle tooth surface side gap can meet the requirements.

3) improving the foundation of reducer


The original independent wall slab concrete foundation is removed, an integral steel base is designed and installed, and the bottom width of the steel bottom seat is widened to 1730m, which is basically close to the input of the reducer, the total length of the output shaft and the fixed anchor bolt of the steel pedestal. On the one hand, the support span of the reducer is increased to ensure the overall stability; on the other hand, the weight of the reducer foundation is increased to reduce the overall center of gravity of the reducer assembly.

The newly made steel base is machined at the top and bottom to ensure the flatness of the base surface and the contact area with the reducer. The improved steel base and installation dimensions are shown in figure 3.

(3) effect verification


After the improvement, the vibration value of the mill operation is obviously reduced, all parts of the equipment are stable, and the vibration value no longer appears in the operation process, which greatly improves the continuous operation ability of the production system, avoids the abnormal operation and shutdown emergency repair of the production belt caused by the abnormal transmission system, reduces the maintenance cost and improves the operation efficiency.

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