The structure and working principle of the planetary ball mill

Figure 1 shows the structure of a domestically produced planetary ball mill . It is mainly composed of a machine base, a grinding cylinder, a main shaft, a male turntable and a transmission.

1-large gear wheel; 2-frame; 3-spindle; 4-feed hopper; 5-hollow polygonal feed turntable; 6-spiral body; 7-hollow shaft; 8--shield; 10-milling cylinder; 11-fixed gear; 12-intermediate gear; 13-discharge screen; 14-grinding rear end plate; 15-moving sealing disc; 16-discharge trough; 17-receiver cover; Sealing ring; 19-rotating gear; 20-grinding cylinder rear end shaft; 21-male turntable; 22-discharge port

The large gear wheel 1 driven by the motor via the pinion gear is mounted on the front end of the main shaft 3 via a bearing; the main shaft is mounted on the machine base 2, and both ends of the hollow shaft 7 uniformly mounted on the large gear 1 through the bearing are respectively connected with the front end plate of the grinding cylinder 9 is connected to the inner side of the top corner of the feed turntable 5, the center of the feed turntable 5 is sleeved through the main shaft 3 and the feed hopper 4, and the rear end shaft 20 of the wear cylinder is mounted on the male turntable 21 at the rear end of the main shaft by the bearing and mounted. There is a rotating gear 19 which is meshed with the fixed gear 11 fixed on the main shaft via the intermediate gear 12. The inner end of the spiral body 6 is fixedly connected with the protective cover 8 installed in the front end plate of the grinding cylinder. The protective cover is mainly for allowing the material to enter the grinding cylinder. The utility model is also designed to prevent the material medium in the grinding cylinder from damaging the spiral body. One end of the spiral body 6 is movably connected to the outer side wall of the feeding turntable 5 through the hollow shaft 7 through the bearing; the discharging sieve plate 13 is installed at the rear part of the grinding cylinder 10 The trough 16 is distributed on the side wall of the discharge chamber formed between the discharge sieve plate 13 and the rear end plate 14 of the grinding cylinder, and the dust collecting cover 17 is placed on the discharge cavity, and the discharge opening is opened below the dust collecting cover. twenty two. In order to reduce vibration, noise, and efficiency during operation, the number of sides of the hollow polygonal feed carousel 5 coincides with the number of the grinding cylinders 10 and is equal to or greater than three. In order to prevent dust leakage, a dynamic sealing disk 15 and a sealing ring 18 are installed between the discharge chamber and the dust cover.

During operation, the motor-driven large gear disk 1 rotates around the main shaft 3, so that several grinding cylinders mounted on the large gear disk rotate together with the male rotary disk at the rear end to form a revolution; since the fixed gear mounted on the main shaft does not rotate, it is forced to The meshing intermediate gear drives the rotation gear to rotate, so that the grinding cylinder rotates while being revolved to rotate the planetary gear train; the material enters the feeding turntable from the feeding hopper, and the feeding turntable is polygonal and rotates with the large gear disk. , the material can be distributed near the top corner of the feed turntable, and the spiral body in the hollow shaft at the top corner is fixedly connected with the protective cover by the inner end thereof, so that the material can be forcibly pressed into the grinding cylinder for grinding as the grinding cylinder rotates; The material is moved to the discharge sieve plate while being ground inside the grinding cylinder, and the ground material is separated into the discharge chamber through the discharge sieve plate, and then thrown from the discharge groove on the side wall of the discharge chamber to In the dust collecting cover, gravity falls to the discharge port to achieve the purpose of dry and continuous feeding and discharging.

The working principle of the planetary ball mill is shown in Fig. 2. The rotating arm (ie, the planet carrier) is equipped with several grinding cylinders. The grinding cylinder revolves around the fixed spindle at an angular velocity W in addition to the angular velocity w around its own axis. The grinding cylinder contains abrasive bodies and powders (collectively referred to as materials). Under the action of revolution, a certain centrifugal force is generated, and the impact and grinding between the materials are caused by the rotation, thereby achieving the purpose of pulverization.

Because of the two parameters of revolution and rotation, the mill can easily obtain different pressing force and pulverizing speed to adapt to the processing of powder of different hardness and adjust the production capacity.

There are five main ways to move the material in the planetary ball mill: 1 pulsation. The material is separated from the revolution center by the group as a whole, and after moving to a certain angle with the cylinder, it slides in the opposite direction of the rotation, and the grinding body avoids pushing the powder layer in the grinding machine to apply compression, shearing and friction to the material. . 2 thrown. After the material is turned to a certain angle with the grinding cylinder, it is thrown off the wall when the pressure of the cylinder wall is equal to zero, and the material is impacted. 3 circulation. The material rises along the concentric circular path, and then the layer leaches down in a circulating state, and the powder is subjected to extrusion grinding and friction. 4 The material moves in a circular motion with the grinding ball and slides relative to it, applying friction to the powder. 5 close. The material at the wall of the cylinder rotates without sliding of the grinding cylinder and loses the pulverizing effect, but can be used to protect the inner wall of the grinding cylinder and reduce wear. Among them, the main effects of superfine pulverization are circulation and sliding motion.

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