In normal gear transmission, in most cases, there will be two pairs of gear teeth at the same time. If the tooth side clearance is small, there are manufacturing errors such as pitch error and tooth shape error, which may cause a pair of gear teeth to barely complete the meshing. process. At the moment when the press is subjected to the impact load, the relative friction between the meshing teeth is larger, which will cause more noise. If the problem tooth is encountered at the same time, the noise will be more severe, but the deformation and fracture of the plate will be caused by the load. The cover of the violent sound is difficult to judge. In practice, only the noise during idle operation is detected. In the press, compared with the meshing pinion, the problem gear teeth are prone to occur during the manufacturing process of the eccentric large gear, and the relative position of the eccentric large gear and the crank is fixed, so the "problem gear teeth" and the crank in the eccentric gear The relative position is also fixed. If the cycle emits noise during the no-load operation of the press, it is mostly caused by the problem teeth on the large gears of the low-speed gear transmission. In fact, the two pairs of meshing teeth may also be squeezed. This state may occur during the meshing process of the full tooth profile, or it may occur instantaneously at a certain part of the tooth profile, which may occur at the height of the tooth profile. Or where there is an error in the width direction. Obviously, even if no load is applied, the tooth profile between the pinching conditions will be elastically deformed by the pressing, and an additional positive contact pressure between the meshing points is formed, so that the frictional force is increased and the noise is increased. Therefore, for the press, there will be noise during the idle process at no load and at the load.