The fixing method of the star coupling and the discrimination between good and bad

Published: 2018-08-21

The choice of the type of star coupling should be based on the size of the transmitted load, the speed of the shaft, the installation accuracy of the two connected components, etc., refer to the characteristics of various star couplings, and choose a suitable star coupling type .You can select the appropriate star coupling according to the type, purpose and use environment of the motor.When selecting, note that the rated torque in the data is greater than the system load torque, and the rated torque has taken into account the variable load factors during operation.Also consider the size and nature of the torque to be transmitted and the requirements for the buffer and vibration reduction function, the size and direction of the relative displacement of the two shafts, the working speed of the star coupling and the amount of centrifugal force caused, the star coupling The manufacturing, installation, maintenance and cost of the star coupling, as well as the performance and working environment of the star coupling.Confirm that the designed aperture and rotation speed conditions cannot exceed the large aperture and high rotation speed in the data. If either of the large aperture or rotation speed cannot meet the design conditions, the size must be changed.Confirm whether other values ​​such as dimensions and specification sheets also meet the relevant conditions of the design.

The quenching and tempering treatment of star couplings is widely used in various important structural parts, especially those connecting rods, bolts, gears and shafts that work under alternating loads.The quenching and tempering treatment of the star coupling is generally used to combine the heat treatment of quenching and high temperature tempering as the quenching and tempering treatment.

Metal heat treatment is one of the important processes in mechanical manufacturing. Compared with other processing processes, heat treatment generally does not change the shape and overall chemical composition of the workpiece, but by changing the internal microstructure of the workpiece, or changing the chemical composition of the surface of the workpiece , Give or work performance.

Fixing method of star coupling

1. Locating screw fixation: The two locating screws have a gap of 90º to lock the fixed shaft. In the traditional fixing method, because the front end of the screw contacts the shaft, it may cause damage to the shaft or difficulty in disassembly.

2. Clamping screw fixation: Utilize the tightening force of the hexagon socket bolt to shrink the slit and clamp the shaft tightly.This method is convenient to fix and disassemble, and will not cause damage to the shaft, so it is a very common fixing method.

3. Keyway type fixation: suitable for high-torque transmission. In order to prevent axial sliding, it is usually used together with positioning screws and clamping screws.

4. D-shaped hole fixation: Generally, if the motor shaft is D-shaped, if the positioning screw cannot be fixed, the hole of the star coupling can be processed into a D-shaped hole corresponding to the size of the motor shaft. With the positioning screw fixed, there is no need to worry about slipping.

5. Expansion sleeve fixation: tighten and fix the account cover by tightening the four positioning screws on the end face of the star coupling. It is suitable for the connection and fixation of some stepping motors and servo motors with large torque, such as the expansion sleeve diaphragm star. Type coupling, expansion sleeve plum blossom star coupling, expansion sleeve bellows star coupling, etc.

Star coupling distinguishes good from bad

1. Check the gear tooth surface meshing condition of the coupling. The contact area is not less than 50% along the tooth height and not less than 70% along the tooth width. The tooth surface must be free from severe corrosion, wear and cracks.

2. The full circle runout of the outer gear ring of the coupling is not more than 0.03mm, and the end circle runout is not more than 0.02mm.

3. When reinstalling the intermediate tube or other parts, it should be assembled according to the original markings and data.

4. Tighten the bolts evenly with a torque wrench.

5. If it is necessary to remove the gear ring, use tools instead of knocking, so as not to bend or damage the shaft.When reinstalling, heat the ring gear to about 200°C before installing it on the shaft.The interference between the outer gear ring and the shaft is generally 0.01~0.03mm.

Eight operation steps for connecting the hot sleeve of the star coupling:

1. The star coupling is heated to the specified temperature in the heating furnace, and the temperature of the workpiece is detected.

2. Take out the coupling and turn it over and put it in the furnace to continue heating.For example, use firewood to heat large couplings.After 2 to 3 hours, the measuring rod repeatedly measures the hole diameter until the measuring rod of the size can freely enter the coupling hole, and the heating is finished.

3. Lift out the coupling and install the striker, climbing or other tools.

4. Correct the position so that the coupling hole is vertical (for vertical assembly) or horizontal (for horizontal assembly), and clean the coupling hole so that the inner hole is free of debris.

5. Hang the coupling close to the shaft; once again, check the inner hole size with the measuring rod to see if there is the required assembly clearance. If the measuring rod can pass, the assembly can be carried out.

6. Apply engine oil evenly on the mating surface of the shaft.

7. Move the coupling of the star coupling steadily closer to the rotating shaft, align the position of the shaft and the hole, and set it.After the coupling is sleeved in about 1/3, the relative position of the hole and the shaft should be checked again to see if there is any skew. If it is correct, continue to hit the coupling.

8. Install the clamping tool to prevent the coupling from moving on the shaft, and then let it cool down naturally.