Heat treatment of plum-shaped elastic coupling and flat key connection of drum-shaped gear coupling

　　Plum-shaped elastic coupling performance after heat treatment and tempering treatment, it has good comprehensive mechanical properties, good low-temperature impact toughness and low notch sensitivity.
　　The hardenability of steel is good. It can be hardened to Ф28～60mm in water quenching and Ф15～40mm in oil quenching.In addition to quenching and tempering, this steel is also suitable for cyanidation and high-frequency quenching.The cutting performance is better. When the hardness is HB174～229, the relative machinability is 60%.
　　However, sometimes because the size of the plum-shaped elastic coupling hole is not measured or the mating surface roughness does not meet the standard requirements, excessive interference fit is caused, the bearing race is greatly squeezed, and the radial clearance of the bearing itself is caused. The reduction will make the bearing difficult to rotate, heat up, wear intensified or stuck. In severe cases, the plum-shaped elastic coupling will cause the inner and outer races of the elastic cushion to crack during installation.The non-rotating seat ring often adopts a fit with little clearance or interference. In this way, the non-rotating seat ring may produce a small creep, and the contact surface between the seat ring and the rolling element is constantly changed, and the raceway wear of the seat ring is even.The heating temperature of quincunx elastic coupling is usually 560~600℃, and the hardness requirement is HRC22~34.Because the purpose of quenching and tempering is to obtain comprehensive mechanical properties, the hardness range is relatively wide.However, if the drawings have hardness requirements, the tempering temperature must be adjusted according to the drawings to ensure the hardness.For example, some quincunx elastic coupling parts require high strength, so the hardness requirements are high; and some gears and shaft parts with keyways need to be milled and inserted after quenching and tempering, so the hardness requirements are lower.
　　For the calculation of the flat key connection of the drum-shaped gear coupling, 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.Therefore, usually only the calculation of the compression strength or wear resistance of the connection is made.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.The main part of the drum-shaped gear coupling is the half coupling body and the attachment is the locking block. After the improvement, the main body of the half coupling is far away from the motor end, and the inner hole is complete, which ensures the coaxiality requirements of the motor shaft. The main body and the locking block are connected together by hexagon socket screws and spring washers. Since the locking block half coupling is cut after processing, it will not affect the coaxiality requirements of the main body of the half coupling and the motor after assembly. .With this structure, the original line-to-surface contact of the torque transmission part becomes the surface-to-surface contact, and the contact length in the axial direction increases, which in turn increases the contact area between the motor and the coupling, and can also transmit large When the torque is increased, the spring washer between the hexagon socket screw and the locking block has an anti-loosening effect. When the coupling rotates at a high speed, the hexagon socket screw will not loosen.The coupling of this structure has been verified by actual use and can achieve a good torque transmission. In other small coupling structures, this structure can also achieve many good effects.