Our customer has two new dry process production lines, the first 2000t/d production line was put into operation in 1988, the second 2300/d production line was put into operation in 2001, and the two lines share a limestone apron feeder. The machine is made by German company, the specification is 180Omm× 11200mm, the design capacity is 600~800t/h, the installation Angle is 22°, the supporting drive device is rollstarag hydraulic motor and planetary reducer, it has the advantages of stepless speed regulation, large output torque and small footprint. However, since the second line was put into operation, the stone demand doubled, making the apron feeder operation rate doubled, and after more than ten years of operation, many hydraulic components of the driving device have basically reached the limit of service life, and there have been several sudden failures, unable to normal production. Because the imported spare parts are expensive and the purchase cycle is long, our factory decided to transform the drive device of the machine locally. Principles of transformation: 1) Ensure that the maximum transmission capacity of apron feeder can meet the output requirements of the existing two production lines after transformation: 2) Use domestic equipment and have the performance of stepless speed regulation of hydraulic drive device: 3) In order to save costs, the original parts of apron feeder should be used as much as possible, and only the drive device should be reformed: 4 should have the characteristics of preventing apron feeder from sliding down the weight of the material when the apron feeder is shut down due to failure; 5) The installation structure size should meet the space requirements of the site, and no new equipment foundation needs to be made. According to the above principles, coupled with the mature application of variable frequency speed regulation technology in recent years, it is decided to use the mechanical transmission mode of variable frequency speed regulation motor and reducer to replace the original hydraulic motor transmission. Comprehensive consideration, finally choose the domestic reducer. The output end is hollow and uses the locking disc HSD360-12x360 to connect to the apron feeder's drive shaft suspension. Therefore, there is no need to add additional foundation, and it has the characteristics of large speed ratio, large torque, compact structure and small volume, fully meeting the transformation requirements. After the transformation of apron feeder transmission device, ZJXI7 reducer is composed of DT33P direct AC reducer and DT32P planetary reducer. The DC reducer has three drives, the first stage is spiral bevel gear transmission, the second and third stages are helical cylindrical gear transmission: DT32P planetary reducer has two drives are planetary gear transmission. A roller type backstop is installed on the second shaft of the first stage of the DC reducer to prevent the machine from reversing. After our professional modification, the apron feeder returned to normal use and the output was not affected.