Drum gear coupling shaft diameter and tensile strength

　　The tensile strength of the drum gear coupling castings is also aimed at the core role of carbon in the chemical composition. Refer to the previously produced 276Q and 376Q crankcases, the carbon content is 313%～314%, and the silicon content is 210%～211%. , The composition is controlled by a fast spectrum analyzer in front of the furnace, and the tensile strength of the castings can reach more than 250MPa, and the hardness can reach 190～240HBS, which meets the technical requirements of the product.The tolerance of special requirements should be marked directly behind the basic size of the blank, such as 95±1.1. The tolerance of special requirements can be higher or lower than the general tolerance.Under normal circumstances, the dimensional tolerance of a small batch of single-piece blanks cannot be lower than 1-176. The tolerance level range specified by plb, when the required tolerance exceeds the range specified by the library, the dimensional tolerance of the castings shall be from 1-175 after negotiation by the relevant parties. Select from plb.The load category of the traditional system is the basic basis for selecting the type of coupling.For working loads with large changes in impact, vibration and transmission, a drum-shaped gear coupling should be selected to buffer, reduce vibration, compensate for axis deviation, and improve the performance of the transmission system.The torque during frequent starting, forward and reverse rotation, and braking is several times the torque during normal and stable operation. It is overload work, which will inevitably shorten the service life of the coupling elastic element. The coupling only allows short-term overload, generally short-term The overload shall not exceed 2~3 times of the nominal torque, ie [Tmax]≥2~3Tn.
　　In the newly designed transmission system, the seven shaft hole types specified in GB/T3852 should be selected, and the J1 shaft hole type is recommended to improve versatility and interchangeability. The length of the shaft hole is in accordance with the coupling product standard. .For a flat key connection, the possible failure modes are: the working surface of the weaker part is crushed or worn, and the key is sheared.For the actual material combination and standard size, crushing or abrasion is the main failure mode.Drum gear couplings usually only calculate the compression strength or wear resistance of the coupling.Generally speaking, the hub is a weaker part, so the strength of the key connection is calculated by the hub.Because crushing and wear are the main failure modes of the coupling, the material of the key must have sufficient hardness.According to the standard, the key is made of steel with a strength of not less than 600MPa.Double-end stud connection is used in occasions where bolts cannot be used due to structural restrictions or where a compact connection structure is desired.The screw connection does not need a nut and has a smooth exposed surface, but it is not suitable for the connection that is often disassembled, so as not to damage the threaded hole of the connected part.In the set screw connection, the set screw is selected into the threaded hole of one of the connected parts, and its end urges the surface of the other connected part or pushes into the corresponding pit to fix the mutual position of the two parts, and can be transferred Not much force or torque.Tightening the connection can enhance the rigidity, tightness and anti-loosening ability of the connection.For the tensioned bolt connection, the fatigue strength of the bolt can also be improved; for the sheared bolt connection, it is beneficial to increase the friction in the connection.The axial tension of the bolt when the bolt is tightened is called the pre-tightening force.The fundamental problem of anti-loosening of threaded connection is to prevent the relative rotation of the threaded pair.It can be divided into three types: using friction, directly locking and destroying the thread pair relationship.The triangular thread can be self-locking, but the connection may still be loose when subjected to shock, vibration, or large temperature changes.
　　The shaft diameter adjustment connection type of the drum gear coupling, namely the shaft hole diameter d and the shaft hole length L, should meet the requirements of the shaft diameter of the driving and driven ends, otherwise the specifications of the coupling should be adjusted according to the shaft diameter d.It is a common phenomenon that the main and driven end shaft diameters are different. When the torque and speed are the same, and the main and driven end shaft diameters are different, the coupling model should be selected according to the larger shaft diameter.