B1200 heavy duty coal apron feeder produced by our company, the feeding speed is 0.012 ~ 0.035m/s, the motor is YCT250-4A, the primary reducer NGW92-11, the secondary reducer WHX360, which is used for limestone conveying. The machine can transport the maximum material particle size of 450mm, limestone from the storage bin several meters to the bottom of the floor, so that the bottom long-term bearing impact load and materials in the storage port under the accumulation of the bottom plate to bear static load. Section view of receiving section at tail end of Coal Apron Feeder. In order to prevent the deformation of the bottom plate, five heavy steel rails are evenly distributed under the bottom plate, and the sleeper is auxiliary under the rail.
Each base plate is drilled with 4-21 holes and fixed to both sides of the M900 chain plate (ISO1977/1-1976 standard) with four M20 bolts. Cross-section diagram of the bottom plate. The bottom plate is formed by hot pressing of 16MnRe18mm thick steel plate. In order to prevent the leakage of the gap between the adjacent feeding bottom plates, square steel strips are welded to the bottom plate. Both sides of the retaining material Q235, 10mm thick, vertically welded to the bottom plate. The head of the unit has two driving sprockets, the tail has two tensioning sprockets, screw tensioning device.
The minimum clearance between the bottom plate and the fixed frame must be guaranteed in the design, manufacture, installation and debugging. Clearance between guard plate and guard edge.
1. Clearance between guard edge and support.
2. Gap between the height of the guard and the supporting plate of the protection plate
3 roller pin shaft end channeling momentum and clearance with the column
4. If the minimum clearance of normal operation cannot be guaranteed, rigid impact will inevitably cause destructive accidents.
2) The manufacturing quality of the two parallel equidistant traction plate chains in the unit is poor. Chain plate pitch manufacturing precision is poor, resulting in excessive cumulative error
Poor, two traction chains run out of sync, resulting in dislocation, increase traction resistance during operation. Secondly, drive sprocket tooth shape and chain groove position processing dislocation, resulting in two chain transmission is not synchronous, the size of the tensile stress, one of the running resistance exceeds the plate chain bearing load and broken chain. In order to eliminate the influence of this manufacturing error, one of the tensioning sprocket is not provided with a keyway, forming the structure of the cruise ship, but the error is too large will leave a future problem.
3) The bottom plate slides on five steel rails. Because the ties bear the impact for a long time and produce plastic deformation, five steel rails cannot be guaranteed.
The rail is in the same plane to support the bottom plate, and the supporting surface is reduced, which causes the bottom plate deformation and increases the sliding resistance on the rail.
4)Coal apron feeder bottom plate is formed by hot pressing, and the distance of arc S is small. When the bottom plate is rotating on the head and tail sprocket, the two adjacent bottom plates will collide at the top Angle of the arc degree of the sprocket, and the chain plate group will run by force, causing the chain to jump on the tooth shape of the sprocket and increasing the traction resistance.
2.2 Roller shaft sleeve on the chain plate is broken
The basic structure of M900 chain roller, due to the powder metallurgy oil-bearing sleeve to withstand the above impacts for a long time,
Its load capacity is poor, easy to fracture.
2.3 Traction power failure caused by improper matching and selection of reducer
The matching of reducer is first determined by the transmission scheme, the traditional scheme is: in the low speed operation of heavy load, impact of the working environment
Under, the general motor - reducer - open gear - drive sprocket structure. This structural design covers a large area and is reliable in use, but requires the manufacture of large modulus gears. Because it is difficult to produce large module gear in general factory and in order to reduce the area of the unit, the motor - I planetary gear reducer - II worm gear reducer through the coupling drive sprocket. The fracture of worm gear crown occurred after less than one year of use. From the design of transmission analysis, bearing impact load transport machinery, with open gear is more practical and reliable. Some unpredictable usage and manufacturing factors should be considered in the design of the power matching technical scheme, so the power allocation should leave some room.
3. Improvement measures and effects
1) Remove the original tie and rail in the receiving section of coal apron feeder, adopt three rows of supporting wheel device to support the bottom plate, and change the sliding support to rolling support
This rigid support can reduce the deformation and running resistance of the bottom plate, which is reliable in operation and convenient in maintenance, as shown in Figure 5.
Section view of the improved delivery system
1. Supporting wheel; 2. Supporting shaft; 3. Support device bracket; 4. Bottom plate In addition, because the bottom plate is made of 16MnRe steel plate, it needs to be hot-pressed by 1000t oil press, and the bottom plate has very large stiffness
So it is feasible to adopt rigid support.
2) The powder metallurgy oil-bearing bushing of M900 chain roller is replaced with 2210 single row centripetal short cylindrical roller bearing, as shown in Figure 6.
Under the condition of normal lubrication, the operation resistance is small, and the load-bearing is safe and reliable.
1. Pin shaft into grease channel; 2. Supporting wheel; 3. Bearing; 4. Outer chain plate
3) Tensioning tail wheel spring tensioning device consists of 4 channel steel slideway, easy to deformation and bending. With Q235, δ=14mm steel
The plates are made of 45° reinforcement plates and welded on the groove plates and columns to increase the stiffness of the stressed parts of the tailframe, as shown in Figure 3.
4) The original design of the bottom plate S=5mm, increase S to 10mm, solve the two adjacent bottom plates in the head and tail sprocket
Collision at the circle of rotation.
5)Coal apron feeder tail receiving section column and beam original structure, welding structure long-term impact vibration is easy to welding. Current drawing
7b bull leg strut structure, impact resistance, more reliable use.
6) The two-stage reducer adopts special reducer, which has no problems in the past two years and is reliable in use.
