Abstract: There are three kinds of beam movements of mechanical transmission tire curing press, namely, lifting and overturning movement, lifting and translating movement and direct lifting and lowering movement. These three movements are all realized by the crank-slider mechanism. Because the beam has to go through an inflection point in the first two movements, its slider mutates into a guide wheel, which can move up and down directly, and both the slider and the guide wheel are used. The reducer turns the crank through the reduction gear. The fixed fulcrum of the crank is the frame, the moving fulcrum is connected with the lower end pin of the main connecting rod, and the upper end of the main connecting rod is connected with the end pin of the cross beam. When the crank rotates, the main connecting rod pushes the end shaft of the beam to move along the given trajectory. Among the three forms of motion, the first two are basically the same, but the auxiliary motion is different, and the third is only a part of the first two. Therefore, when the curing press opens the mold to the end, the beam is in three different States. Therefore, it is suitable for different types of vulcanizers. I. Lifting and overturning movement According to the literature, the forms of lifting and overturning movement are divided into: indirect guiding lifting and overturning movement; Directly guided lifting and overturning movements; Lifting and overturning movement guided by single slot lever. Among them, the most commonly used and simplest is the direct-guided lifting and overturning movement. Single-slot lever-guided lifting and overturning movement has been used in large-scale B-type vulcanizers such as 1900B and 2 160B, but it is gradually replaced by direct lifting and overturning movement. However, the indirectly guided lifting and overturning movement has not been used in domestic setting vulcanizers. The lifting and overturning motion introduced in this paper is a direct guiding lifting and overturning motion. The main guide wheel outside the beam end shaft and the auxiliary guide wheel on the auxiliary connecting rod directly discuss the motion of the beam end shaft. The trajectory of the beam consists of a vertical open main guide groove and an open guide rail connected with it, and the included angle of the guide rail is less than 90 degrees. In order to keep the beam moving smoothly and realize the rotation of the beam, there is also a closed auxiliary guide groove, which is parallel to the open main guide groove. When the mold is opened, the end shaft of the cross beam rises in the opened main guide groove, and the central shaft of the lower end of the auxiliary connecting rod fixedly connected with the cross beam rises synchronously in the closed auxiliary guide groove, at this time, the cross beam translates. When the beam end shaft leaves the vertical open main guide groove and enters the open guide rail, the motion track of the beam end shaft is no longer parallel to the closed auxiliary guide groove. At this time, under the action of the main link and the auxiliary link, the beam end shaft rotates while moving on the opened main guide rail. At the limit position of the beam movement, the center lines of the two movable pins of the main connecting rod coincide with the center lines of the crank fulcrum. In actual movement, the limit position is generally not reached. φ = α+β, where α is the included angle between the auxiliary connecting rod and the vertical center line of the beam β=arcSin, where H and L are determined by the structure of the beam itself, and they also determine the value of α. It can be seen from this formula that the rotation angle of a beam depends on its own structure first. After its structure is determined, it is related to the mold opening length of vulcanizer. When the mold is opened to the limit, its rotation angle reaches the maximum. Until the end of the 20th century, almost all B-type vulcanizers used lifting and overturning movements. This is determined by the characteristics and application scope of type B curing press. First of all, when the B-type center mechanism is loading and unloading tires, the capsules are completely straightened, so that the upper ring rises very high. Secondly, the grippers of vulcanizers used in the early days were all long, and the tires at that time were mainly bias tires, and the height of raw tires was also large. In order to load the green tire into the lower die smoothly, there must be enough space above the central mechanism. Adopting the movement form of lifting and turning, the top of the central mechanism is completely opened in the state of completely opening the mold, which makes the tire loading and unloading operation very convenient. Thirdly, we know that after the tire is vulcanized, the adhesion between the tire and the vulcanized model is great. Its value is not only proportional to the contact area between the tire and the model, but also the adhesion per unit area increases with the increase of the contact area. This makes the adhesion of large tires such as truck tires and bias tires very large, which greatly increases the difficulty of demoulding and even strains the tires. In order to reduce adhesion, the most commonly used method at present is to spray release agent (mixed solution of silicone oil and water) on the model. But it is only convenient to do this operation after the upper die is turned over to a certain angle. Generally speaking, the setting vulcanizer with specifications above 1525 should have an automatic spraying isolation agent device. Foreign companies pay more attention to this, but domestic companies don't seem to care much. Almost all die adjusting mechanisms of tire vulcanizer adopt screw pair structure. Under the condition of good lubrication, this structure is convenient and reliable to adjust and has large bearing capacity. However, the clearance of the thread pair is larger than that of other matching. Especially, the mold adjusting mechanism is affected by the high temperature in the curing chamber, and the clearance of its screw pair is larger than that used at room temperature. When the vulcanizer opens and closes the mold, the gap distribution of the volute pair changes continuously from vertical state to near horizontal state or from near horizontal state to vertical state. With the continuous mold opening and closing of vulcanizer, this change of gap distribution is repeated. Obviously, it not only affects the stability of the movement, but also damages the matching accuracy of the screw pair, thus affecting the coaxiality between the upper and lower dies, the upper die and the central mechanism. When the movable die is used, the piston rod of the working cylinder of the movable die is pressed to one side after the cross beam is turned over. The connection between the piston rod and the sidewall die on the moving die will affect the accuracy and service life of the model, the cooperation between the piston rod and the cylinder, and even cause the leakage of the cylinder. 2. When the up-and-down translation motion is in the form of up-and-down translation motion, the trajectory of the beam end shaft is basically the same as that of up-and-down overturning motion. The fundamental difference is that its auxiliary guide groove is a closed guide groove, and its center line is exactly the same as the center movement track of the beam end shaft. Therefore, in the whole movement process of the cross beam, the trajectory of the center of the end shaft is completely consistent with that of the center of the auxiliary connecting rod shaft. The beam keeps translating. Fig. 2 is a schematic diagram of its mechanism movement. No matter whether the tire loading mechanism is fixed in front of the beam, when the mold is completely opened, the top of the central mechanism is completely opened, just like the lifting and overturning movement. Because the cross beam has not turned over, the thread pair of the die adjusting mechanism is always in a vertical state. Compared with the lifting and overturning movement, it not only improves the stability of the movement, but also greatly improves the repetition accuracy of the opening and closing mold, which makes it easier to ensure the coaxiality between the upper and lower models and the central mechanism, and also improves the use conditions of the model, especially the moving model and its control cylinder. By the end of the 20th century, just like all mechanical transmission type B setting vulcanizers used lifting and overturning movements, all models other than type B, such as type A, AB and C, used lifting and translating movements. This is because Type A, AB and C are generally only used for curing small and medium-sized tires, and it is usually unnecessary to spray release agent. Especially for small and medium-sized radial tires, the curing quality of tires can be improved to some extent by adopting lifting and translating motion. According to the previous discussion, it is reasonable to use lifting and overturning motion for large-scale B vulcanizer because it needs to spray release agent. However, it is puzzling that all B-type vulcanizers, including 1030B vulcanizers for curing small tires, also adopt lifting and overturning actions. The acceptable explanation can only be for the standardization and serialization of equipment and easy management. Third, the straight move is actually only a part of the lifting and translation movements. It draws lessons from the movement mode of hydraulic transmission tire setting vulcanizer, and the beam only rises and falls right above the central mechanism. Obviously, the direct lifting movement is simpler and easier to realize than the first two forms of movement. At the same time, because the beam only moves up and down in one direction, its motion accuracy is greatly improved. In the lifting, overturning, lifting and translating movements, the crank swings around the fixed fulcrum in a certain angle range, and the whole transmission device moves back and forth. In the direct lifting movement, the crank rotates once, the beam completes a lifting cycle, and the transmission device does not need to be reversed. For direct lifting movement, the maximum lifting height of the cross beam is equal to twice the length of the crank. Due to the limitation of equipment size, it is impossible to make the crank very long, so the height of mold opening is very limited. It is not suitable for type B vulcanizer, and can only be used for vulcanizing passenger car radial tires and passenger car radial tires in type A, AB and C vulcanizers. The movement form of direct lifting makes the accuracy of mechanical transmission tire setting vulcanizer reach a new height. At present, under the condition that the hydraulic drive tire setting vulcanizer has not been popularized, it can partially replace the hydraulic vulcanizer to vulcanize high-grade small radial tires. To sum up, the application of three motion forms of mechanical transmission tire setting vulcanizer should be divided into: B-type vulcanizer vulcanizes large tires (generally above 1525B), and adopts lifting and overturning motion; Generally, the B-type vulcanizer adopts lifting and translation movement; Other types of vulcanizers other than B-type, especially those used for radial tire vulcanization, give priority to direct lifting motion, while those that cannot be used adopt lifting translation motion. With the progress of science and technology, tire vulcanization technology will continue to develop. If the process of spraying release agent on the upper mold can be cancelled, the Popo can be realized, and the lifting and overturning motion will disappear during the movement of the tire setting vulcanizer. At that time, the mechanical transmission tire setting vulcanizer will only have two forms of movement: lifting, translation and direct lifting. All type B curing presses use lifting and translation movements, while other types of curing presses use both movements. If so, the motion accuracy of the mechanical transmission tire setting vulcanizer will be greatly improved.