What factors cause the damage of the drum gear coupling?

The axial play of the main motor shaft is too large

This motor is supported by sliding bearings. The factory standard axial play of the rotor is 5% of the motor's magnetic base, and the position of the magnetic base is not indicated. However, the allowable axial play of the gear coupling is 5%. It is precisely because the axial play of the main motor's rotor is greater than that of the drum gear coupling that during the start and stop of the main motor, The axial movement of the rotor exerts a tremendous impact force on the gear coupling, causing damage to the gears.

Improper motor installation

Because the motor was not marked with the position of the magnetic base, when the motor was statically installed, the rotor position was not in the position of the magnetic base, and the influence of the motor's magnetic base was ignored during the installation process. When the motor rolls, due to the control effect of the gear coupling, the motor rotor cannot be positioned under the magnetic base, which intensifies the impact on the gear coupling and accelerates the damage of the gear shaft

The structure and principle of the drum gear coupling before improvement

The connection between the motor and the coupling before the improvement was: The mating part between the motor and the half coupling 4 is 6mm, with a length of 32mm. There is no keyway on the shaft, making it impossible to complete the key connection for torque transmission. According to the installation requirements of the motor, the motor and the half coupling hole are selected for transition mating. The torque is mainly transmitted by the two M5 set screws fixed on the half coupling. During use, this structure has the following deficiencies:

(1) The contact between the motor shaft and the set screw is a linear surface contact, and the contact surface is particularly small, resulting in very limited torque transmission.

(2) Threaded connections do not have anti-loosening functions. Through several disassemblies and reassemblies and long-term operation, relative rolling and axial movement between the half coupling shaft and the motor shaft will occur, causing the equipment to be unable to operate.

The fault factors of the drum gear coupling: The load-bearing capacity and service life of the drum gear coupling depend on the contact strength, while the tooth surface curvature radius and the tooth meshing Angle directly affect the contact strength. The relationship between the tooth meshing Angle, curvature radius and contact strength is as follows: contact stress F - circumferential force received by the gear E - elastic modulus of the material - tooth surface curvature radius - displacement circle radius - meshing Angle - meshing height of the internal and external teeth The radius of curvature of the tooth surface and the meshing Angle of the teeth directly affect the touch stress. A smaller meshing Angle results in a larger radius of curvature, and a larger radius of curvature leads to a smaller touch stress. The meshing angles of drum gear couplings abroad are 20°, 21.5°, 28° and 30°. We choose a 20° meshing Angle, which is beneficial for reducing contact stress. ① Severe wear on the tooth surface.② Large axial displacement occurs in the internal gear ring, to the extent that it cannot mesh.③ Broken teeth occur.④ The mating bolts of the coupling are broken. Faults of the coupling for lifting accessories: ① Severe wear on the tooth surface. ② The axial displacement of the internal gear ring is relatively large, and it may even fail to mesh. ③ Tooth breakage occurs. ④ The mating bolts of the coupling are broken. The primary factor contributing to the above description is the lack of oil or insufficient oil in the drum gear coupling of the lifting accessory. The levelness and coaxiality errors of the two shafts are too large, exceeding the compensation range of the coupling, causing inaccurate meshing between the shaft teeth and the internal teeth, resulting in partial contact and generating additional torque.