Structural Deviation of Plum Blossom Coupling

The structure introduction of the plum blossom coupling:

The structure of the plum blossom coupling is simple, the number of parts is small, the radial dimension is small, and no lubrication is required; the elastic element has a high pressure bearing capacity. Except for the double-flange quincunx elastic coupling, when replacing the quincunx-shaped elastic parts of the wearing parts, it is necessary to move the half-coupling axially. This coupling has the ability to compensate for the relative offset of the two shafts. There are two main types of plum blossom couplings, one is the traditional straight claw type, and the other is the curved surface (inner concave) claw type zero-clearance coupling. Traditional straight jaw couplings are not suitable for use in high precision servo drive applications. The zero-clearance claw type plum blossom coupling is evolved on the basis of the straight claw type, but the difference is that its design is suitable for the application of the servo system, and is often used to connect servo motors, stepping motors and ball screws.

Introduction of plum blossom coupling:

The plum blossom elastic coupling is to install an integral plum blossom-shaped elastic ring between the claws of two half-couplings of the same shape to realize the connection of the two half-couplings. The power is transmitted through the extrusion between the claw and the elastic ring, and the relative offset of the two axes is compensated through the elastic deformation of the elastic ring to achieve vibration reduction and buffering. Each form has 14 specifications, they are suitable for shaft hole diameter d=12-160mm, shaft hole length L=35-135mm, nominal torque T=25-25000N.m, allowable speed [n]=1500- 15300r.min. This coupling has been standardized, and there are five structural forms formulated by GB/T5272-2002: LM type (basic type), LMD type (single flange type), LMS type (double flange type), LMZ-I type ( Split brake wheel type) and LNZ-II (integral brake wheel type).

The structural deviation of the plum blossom coupling:

Torx elastic couplings have good balance performance and are suitable for high speed applications (up to 30,000 rpm), but cannot handle large misalignments, especially axial misalignments. Larger eccentricities and deflection angles create greater bearing loads than other servo couplings. Another issue of concern is the failure of plum blossom elastic couplings. Once the plum blossom elastic spacer is damaged or fails, the torque transmission will not be interrupted, and at the same time the metal claws of the two bushings are engaged together to continue to transmit torque, which is likely to cause problems in the system.

The deviation problem of the plum blossom coupling is analyzed as follows:

1. The plum blossom elastic coupling can transmit torque and rotation angle, and absorb the deviation of the shaft at the same time. When the installation deviation exceeds the allowable value, vibration may be generated or the life of the coupling will be shortened, so the deviation must be adjusted properly.

2. Deviations do not only occur in equipment assembly, vibration, thermal expansion, bearing wear, etc. during the working process will cause deviations. Therefore, it is recommended to adjust the axial misalignment to less than 1/3 of the maximum value.

3. There are three kinds of shaft deviations, namely radial deviation, angular deviation and axial deviation. Please adjust the deviation so that it is less than the allowable value listed in the specification sheet of each product.

4. The allowable value of large deviation listed in each product means that when only one kind of deviation exists, when two or more deviations exist at the same time, the allowable value should be lower than 1/2 of the large deviation in each specification table.