Tire Mold Structure Classification And Working Principle

The guide surface of the active mold guide mechanism is an inclined plane, which is called an inclined plane type tire active mold. During the opening and closing process of the inclined plane type mold, the middle mold sleeve and the bow seat are in plane contact. The number of mold bow seats is generally 8 to 10, and 8 to 10 inclined planes need to be processed on the bow seat and the middle mold sleeve that matches it. In order to ensure that the finished tire does not have rubber edges and misaligned appearance quality problems, the mold closing accuracy of the inclined plane mold is very high. The inclined plane processing on the mold requires 8 to 10 planes to be equally divided into a circle and the planes are all centripetal, and the centripetal angle of the inclined plane should be consistent. Ordinary processing machine tools cannot meet such high precision requirements, and special CNC machine tools are required for processing. After the mold parts are worn, there will be a diameter error inside the pattern block, which will reduce the roundness of the vulcanized tire and easily cause tire rubber edge problems. However, the inclined plane type mold has low requirements for the flatness of the upper and lower hot plates of the vulcanizer and has good adaptability. The guide surface of the active mold guide mechanism is a conical surface, which is called a conical surface active mold. Compared with the inclined plane, the conical surface has good machinability, and ordinary machine tools can meet the precision requirements. The assembly precision requirements of the conical surface mold are low. After the mold parts are worn, the circumferential deviation can be automatically compensated, which has little effect on the roundness of the vulcanized tire, and has no obvious effect on the rubber edge and misalignment of the tire. However, during the opening and closing of the mold, the wear-resistant plates on the bow seat and the middle mold sleeve gradually transition from line contact to conical surface contact, resulting in uneven wear of the wear-resistant plates, unstable mold movement, and low adaptability to the vulcanizer.
At present, the heating methods in the tire vulcanization process are steamer type and hot plate type. Steamer heating is to heat the mold in a sealed vulcanizing tank; hot plate heating is to have two heating sources on the mold: one is the upper and lower hot plates of the vulcanizer, with a temperature of about 150°C, which is used to vulcanize the tire sidewall; the other is to pass water vapor at about 160°C into the air chamber of the mold's middle mold sleeve, and the heat energy is transferred inward through the bow seat to the tread block to vulcanize the tread pattern part. The difference between the steamer-type and hot plate-type mold structures is that the steamer-type middle mold sleeve does not have an air chamber, while the hot plate-type middle mold sleeve has an air chamber that is processed and superheated water vapor is passed into the mold heat source. Before the tire blank is loaded into the vulcanizer, the mold needs to be preheated for a period of time so that the mold reaches the temperature required for tire vulcanization. The vulcanizer drives the mounting ring and the middle mold sleeve to move upward, and the bow seat drives the tread block to move radially to realize mold opening. Then the robot grabs the tire and places it on the curing bladder of the center mechanism of the vulcanizer. After positioning, the upper cover and upper side plate of the mold move downward under the action of the vulcanizer, and the bow seat and the pattern block are radially molded into a full circle under the force applied by the middle mold sleeve. The tire is heated for a period of time at a certain temperature and pressure, and the tire is vulcanized into a finished tire.