Apron feeder is a kind of feeding equipment with strong impact resistance and suitable for complex working conditions.Under the impact of ore, the chain apron of heavy apron feeder and the bearing in its supporting roller system are often damaged, which causes frequent faults of heavy apron feeder.In this paper, the finite element analysis software is used to simulate and analyze the ore impact chain apron and the supporting mechanism (the stress structure consisting of channel steel and I-steel), and it is found that the stress at the rigid support of the chain apron is great during the impact process.The deformation of the chain apron and the supporting mechanism makes the original 5-point support become 2-point support at both ends, which aggravates the failure of the chain apron and the bearing of the roller system.
Heavy apron feeder is a kind of heavy equipment widely used for mine feeding. Its main function is to evenly distribute the ore falling from the ore funnel to the belt conveyor .In practical production, the failure of the bearing in the chain apron and its supporting roller system often occurs, which makes the fault of heavy apron feeder occur frequently.After a long time of observation and analysis, it is found that there are mainly two direct factors affecting the failure of heavy-duty apron feeder. First, if the chain apron is empty, the ore will directly impact the chain apron from a height of 10 m, and the impact force will be enough to make the chain apron feeder and the support roll deformation or even fracture.Second, under normal working conditions, the middle part of the chain apron liner and the supporting foundation of the idler will deform and sag after a period of work (impact), leading to the theoretical existence of 5 idlers supporting the chain apron in each row, while in fact, there are mainly 2 jobs on the outside, shortening the service life of the idler.Experienced and responsible positions will always leave a certain thickness of ore on the surface of the chain apron waiting for the next mine.This can play a large buffering effect, thereby protecting the chain apron.
The ore falls freely from a high place and has an impact on the chain apron, which is supported by five support rollers. The stress distribution of the chain apron after being impacted will affect the stress status of each support roller. Therefore, the stress distribution of the chain apron after being impacted by the ore should be analyzed.During the whole transportation process, the ore is in free fall with a height of 10 m, and finally falls into the selection of the most suitable processing method due to the factors such as the amount of chain apron, raw materials, production cycle and processing means.Since the purpose of the analysis is to observe the stress distribution of the chain apron under impact, the ore can be regarded as a rigid body and the rigid support roll as a rigid support.In addition, the free-falling motion at height 10 m is equivalent to the vertical falling motion with initial velocity v0.The whole impact model is simplified as shown in FIG.  In Figure 1, M is the ore. In order to make the analysis more representative, the shape of the ore is set as a sphere with a diameter of D = 350 mm. Its size and weight are similar to the actual size and weight of the ore, so the impact stress is concentrated.In addition, the rigid support is the support
roller, which is in line contact with the chain apron.The supporting mechanism of supporting chain apron of heavy apron feeder is composed of I-steel, channel steel and supporting roller.Because the supporting roller system involves a series of other structures and is relatively complex, only the stress structure composed of channel steel and I-steel is considered in the modeling, ignoring the contact problem between them and taking them as a whole.
During the impact of ore on the chain apron feede, the stress of the rigid support of the chain apron is very great, which will lead to the failure of the bearing of the support roll.Moreover, the maximum stress occurs near the middle of the chain apron (impact point), and the stress value exceeds the tensile strength of high manganese steel, which will lead to the deformation and failure of the chain apron.The deformation of the mechanism will make the supporting roller not have 5 supporting rollers on each i-steel, then the force on each supporting roller  At the same level, the three middle support rollers sink and cannot be supported normally.Causes the bearing on both sides to bear too much force often appears the fault.For the support mechanism, the maximum stress occurs at both ends of the support, and the maximum stress value exceeds the tensile strength of 45 steel, which further proves the fact that the actual work of less than 5 supporting rollers will aggravate the failure of the wheel bearing.Because the above is a simplified model, the stress distribution characteristics of the chain apron support mechanism are deliminator analyzed, and the chain apron support machine obviously, the force T on the support roll is far greater than the rated load of the roll bearing, which makes the roll bearing unable to work normally.Then, the pressure exerted on each small round surface of the model channel corresponding to the stress point of i-steel is as follows: The structure is also subject to other constraints in the actual working process, which will affect its stress distribution, which is also the reason why the stress generated in the simulation analysis is many times greater than the allowable stress.In the actual work, the intermediate buffer device can be designed and the material thickness can be appropriately increased to achieve buffering, and the work schedule can be changed to avoid once the chain apron is empty, the material directly falls from the height of 10 m, causing impact damage to the chain apron support mechanism.In addition, the two sides of I-steel can add floor to improve the strength of I-steel, and then improve its bending ability.Thus extend the use of I-beam in the working process of the feeder