The characteristics of the star coupling and the distribution method of the rotor in the balanced state

Published: 2018-09-02

The characteristics of the star coupling: the star coupling has a simple structure (composed of four pieces), convenient assembly and disassembly, no need to move the connected two shafts during disassembly, compact size, light weight, compensation capability, and accuracy in installation The advantages of low requirements, work, long life, and low cost.The star coupling can be used for shafting transmission of textile, agricultural machinery, lifting and transportation, engineering, mining, light industry, chemical industry and other machinery. It is suitable for high temperature, humidity and dusty working conditions. It is not suitable for high speed and severe impact loads. And the occasion of transmitting axial force, the star coupling should work under the condition of good lubrication and protective cover.

When disassembling the star coupling, the connecting bolts are usually removed first. Before disassembling the star coupling, some marks should be made on the positions of each component of the star coupling for reference when reassembling.For star couplings used in high-speed machines, the connecting bolts have been weighed and clearly marked and cannot be mistaken.When disassembling the star coupling, the connecting bolt is usually removed first.Because a layer of grease, corrosion products and other deposits are deposited on the surface of the thread, the bolt is not easy to disassemble, especially for the heavily corroded bolt, it is very difficult to disassemble.Removal of connecting bolts Choose suitable tools, because the bearing surface of the bolt's outer hexagon or inner hexagon has been slipped and damaged, and it will be difficult to disassemble.For bolts that have been rusted or with a lot of grease stains, solvents (such as rust loosener) are often used to spray the joints of the bolts and nuts to allow the solvent to penetrate into the threads, which will be easy to disassemble.

Scope of application of star coupling:

1. The quincunx-shaped elastic coupling is mainly composed of two protruding teeth that are closely meshed and subjected to radial compression to transmit torque. When the two axes are relatively offset, the elastic element undergoes corresponding elastic deformation, which plays a role of automatic compensation.

2. Plum-shaped elastic couplings are mainly suitable for frequent starting, forward and reverse rotation, medium and high speed, medium torque and high-quality work occasions, such as: metallurgy, mining, petroleum, chemical, lifting, transportation, light industry, textiles , Water pumps, fans, etc.

Features of star coupling:

1. It has the performance of compensating the relative deviation of the two axes, damping and buffering.

2. Small radial size, simple structure, no lubrication, high carrying capacity and easy maintenance.

3. It is suitable for connecting two coaxial lines with frequent starting and variable forward and reverse rotation. The transmission torque is 20-25000N.m, and the working temperature is -35-80℃.

4. The polyurethane elastomer is limited by the convex claw block, which can avoid the internal deformation caused by impact and the external deformation caused by centrifugal force; the large concave surface of the convex claw makes the surface pressure on the involute tooth very small, even on the tooth. Withstand overload, the teeth will not wear or deform.

5. The standard number is JB/T10466-2004, which stipulates eight structural forms of the star coupling, which expands the scope of application.

Rotor distribution method in balance state of coupling:

XNUMX. Balance

Coupling balance refers to a method of checking the mass distribution of the rotor.The mass distribution state should be adjusted to limit the vibration of the bearing journal or limit the force on the bearing.

XNUMX. Types of imbalance

1. Single-sided unbalanced state If the center of gravity of the object is not on the axis of rotation, a single-sided unbalanced state will appear.At this time, regardless of the relative position between the object and the axis, it will not be in a static equilibrium state.Place the journal of the unbalanced object on two parallel horizontal rods or guide rails, and you can observe the angular position and correction amount to be corrected in a single surface.The heavy side of the object always immediately turns to the position below the axis. The adjustment method is to add a counterweight to the radial position of the symmetrical point of the heavy side of the object and the rotation. The static balancer can achieve single-sided balance without rotating the rotor. Centrifugal balancing machines are also often used to achieve single-sided balancing.

2. Double-sided unbalanced state. This kind of unbalanced state will appear when there is an imbalance and a phase difference in the two planes. The phase difference is not 180 degrees. The inertial principal axis originally at the same position as the axis of rotation has left the rotation. The axis is offset. Under normal circumstances, the two axes are skewed with each other. When the rotating cylinder with unbalanced moment, such as a coupling, is not restricted by the bearing, it will rotate around the main axis of inertia, and the main axis of inertia The line coincides with its geometric longitudinal axis.Moments of equal magnitude but opposite directions are sometimes referred to as couple imbalance.

XNUMX. Balanced terminology

1. Rotation axis The rotation axis is the straight line around which the object rotates. The straight line is determined by the journal, the mating surface or the positioning surface of other surfaces.

2. Offset of the principal axis of inertia The offset of the principal axis of inertia relative to the axis of rotation. The two axes may be parallel in some cases, and the coupling is not balanced in most cases, so it is offset in the two commonly used balance planes. The amount of shift often varies.

3. Rigid rotor rotor can be balanced and corrected in two arbitrarily selected planes, at any speed, running under working conditions close to the supporting point of the supporting device, and its imbalance will not significantly exceed the balance tolerance value, then the rotor is a rigid rotor .It should be noted that flexible couplings are usually composed of several parts, and the centering surface of these parts is intermittent and eccentric due to diameter errors.