The Selection of Coupling for Closed-loop Stepper Motor

The integrated stepper motor coupling is mainly used to connect the shaft and the driven shaft to transmit torque and has relatively precise transmission performance.

The Selection Requirement of Coupling

1, Zero Backlash

The coupling doesn’t allow clearance during transmission;

2, High Rigidity

The coupling doesn’t allow the hysteresis of transmission, otherwise, it will seriously affect the precision of transmission.

3, Low Inertia

On the basis of ensuring the strength of transmission, it should reduce the weight of the coupling.

4, Good Flexibility

The precision coupling not only requires high rigidity but also needs to correct various deviations between the driving shaft and the driven shaft generated during installation.

The Type of the Coupling

According to the relative position of the connected two axes and the change of position:

1, Fixed coupling

It is mainly used in the application where the two shafts require strict alignment and no relative displacement will occur when it works.

Simple structure and easy to make, there are the flange coupling, the sleeve coupling, clamp shell coupling, etc.

2, Movable coupling

It is mainly used in the place where the two shafts are skewed or there is relative displacement in the work. According to the method of compensating displacement, it can also be divided into the rigid movable coupling and elastic movable coupling.

The rigid movable coupling uses the dynamic connection formed by working parts which has the degree of motion in one or more direction. There are dental coupling, cross groove coupling, gear coupling, chain coupling.

The elastically movable coupling uses the elastic deformation of the elastic element to compensate for the deflection and displacement of the two shafts. At the same time, it also has the function of cushioning and vibration reduction. There exist serpentine spring coupling, radial multilayer leaf spring coupling, elastic ring bolt coupling, nylon bolt coupling, rubber sleeve coupling, etc.

In the selection, first, we should select the appropriate type according to the working requirement. Then according to the diameter of the shaft to calculate the torque and speed. The appropriate model will be selected from the relevant manual. Finally, it is necessary to make verification calculations for key parts.

The Product in the Market

Plum blossom coupling:

1, High flexibility and rigidity, according to the requirement different elastomers can be selected.

2, Zero Backlash transmission, there exists a great pressing force between elastomers and metal bushing to ensure close contact.

3, The shaft hole adopts a clamping structure to ensure that there is no gap between the shaft and the hole;

4, Polyurethane elastic spacer connection, excellent electrical insulation performance;

5, The ambient temperature is -20 ℃ ～ 60 ℃.

Diaphragm coupling:

1, There are two types: single diaphragm structure and double diaphragm structure, wherein the double diaphragm is more flexible.

2, Compared with other stepper motor couplings, the rigidity is higher.

3, Good thermal insulation performance.

4, There are two types of shaft holes: clamping type and expansion sleeve type. The expansion sleeve type can withstand relatively large inertia.

Elastic coupling:

1, Integrated slit-cut metal elastic coupling

2, Eccentricity, deflection angle and axial deviation allow

3, High Torque rigidity, excellent sensitivity

4, Rotation characteristics in clockwise and counterclockwise are the same.

5, Can cope with the harsh environment.