Drum Gear Coupling: High-precision Coupling-Jiangsu Sitong Cardan Shaft Co.,Ltd
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Drum Gear Coupling: High-precision Coupling

Views:41     Author:Cardan Shaft Manufacturer     Publish Time: 2020-04-30      Origin:Sitong Cardan Shaft Co.,Ltd

The drum gear coupling is a rigid-flexible coupling, which is composed of an internal ring gear with the same number of teeth and a flange half coupling with external teeth. The external teeth are divided into two types of straight teeth and drum teeth. The drum gear coupling can allow a larger angular displacement (relative to the straight tooth coupling), which can improve the contact conditions of the teeth and increase the torque transmission. Ability to extend service life.




Drum gear couplings have the ability to compensate for axial deviations in radial, axial, and angular directions. Compared with straight gear couplings, they have a compact structure, a small radius of gyration, a large carrying capacity, high transmission efficiency, and low noise. The advantages such as long maintenance cycle are especially suitable for low-speed and heavy-duty working conditions, such as metallurgy, mining, lifting and pulping industry, as well as the shafting transmission of various machinery such as petroleum, chemical, and general machinery.

 

The drum gear coupling, model DC, is consisted of seals, the outer end cover, the load-carrying ring, the hub with. crowned spur gear teeth, the flanged housing with internal gear teeth, and the inner end cover.


Selection of drum gear coupling




When selecting a coupling, the coupling should be selected based on the needs of the drive system of the shaft system, and it should be avoided to simply consider the coupling between the master and driven ends. 8 points to consider

 

(1) Consider the mechanical characteristics of the power machine

 

From the power machine to the working time, the main and driven ends are connected by one or several couplings of different varieties or different types and specifications to form a shafting transmission system. In mechanical transmission, power machines are nothing more than electric motors, internal combustion engines and steam turbines. Due to the different working principle and structure of the power machine, its mechanical characteristics are very different, and some operations are stable, and some have impacts during operation, which have unequal effects on the transmission system.

 

(2) Consider the load type

 

Due to the different structures and materials, the coupling capacity of the couplings used in the transmission systems of various mechanical products varies greatly. The load category is mainly to form different types of loads for reasons such as impact, vibration, forward and reverse, braking, and frequent starting of the working load of the working machine. In order to facilitate the selection and calculation, the load of the transmission system is divided into four categories.

 

(3) Consider the allowable speed of the coupling

 

The allowable speed range of the coupling is determined by calculation according to the maximum outer edge size of the linear velocity allowed by different materials of the coupling. The allowable speed range of the coupling is different for different materials, varieties and specifications. Changing the material of the coupling can increase the allowable speed range of the coupling. The allowable speed of steel is greater than the allowable speed of cast iron.

 

(4) The relative displacement of the two shafts connected by the coupling

 

The two shafts connected by the coupling are subject to relative displacement due to various factors such as manufacturing errors, assembly errors, installation errors, shaft loading and deformation, base deformation, bearing wear, temperature changes, and relative motion between components. Under normal circumstances, the relative displacement of the two shafts is inevitable, but the direction of the balanced displacement generated by the shafting transmission under different working conditions, that is, the axial, radial angular direction and the amount of displacement are different.

 

(5) Consider the transmission accuracy of the coupling

 

Small torque and shafting transmission based on transmission motion require couplings with high transmission accuracy. Flexible couplings with metal elastic elements should be used. High-torque and power-transmitting shafting transmissions also have requirements for transmission accuracy. At high speeds, non-metallic elastic components should be avoided. Flexible couplings with gaps between elastic couplings and movable components should be used. Diaphragm coupling with high transmission accuracy.

 

(6) Coupling size, installation and maintenance

 

The external dimensions of the coupling, that is, the maximum radial and axial dimensions, must be within the installation space allowed by the machine. Choose the coupling that is easy to assemble and disassemble, no maintenance, long maintenance period or convenient maintenance, replace the wearing parts without moving the two shafts, and easy to adjust the coupling.

 

(7) Consider working environment

 

Couplings work with various host products, and the surrounding working environment is more complicated. For the working environment of high temperature, low temperature, oil, acid and alkali medium, it is not suitable to use the flexible coupling with general rubber as the elastic element material, and the metal elastic element flexible coupling should be selected.

 

(8) Consider the manufacture, installation, maintenance and cost of the coupling

 

Under the premise of satisfying the convenience performance, the coupling that is convenient for assembly and disassembly, simple maintenance and low cost should be selected. For example, the rigid coupling is not only simple in structure, but also easy to assemble and disassemble. It can be used for low-speed, high-rigidity transmission shafts.



Advantages of drum gear coupling(Compared with the straight-tooth coupling)




1. Strong carrying capacity. Under the same outer diameter of the inner gear sleeve and the large outer diameter of the coupling, the load-bearing capacity of the drum gear coupling is increased by 15-20% on average than that of the straight gear coupling;

 

2. Large amount of angular displacement compensation. At the same modulus, number of teeth, and tooth width, the angular displacement of the drum-shaped tooth is greater than that of the straight tooth;

 

3. The drum-shaped tooth surface improves the contact conditions of the internal and external teeth, avoiding the disadvantages of edge tooth extrusion and stress concentration under the condition of angular displacement, while improving the friction and wear of the tooth surface and reducing Noise and long maintenance cycle;

 

4. Because the side of the drum-shaped tooth is drum-shaped, the axis is inclined at a certain angle, and the contact force is improved for the contact between the drum-shaped tooth surface and the internal tooth surface. The contact condition is improved, the contact stress is reduced, and the ordinary straight tooth gear coupling is changed. The end of the external teeth of the shaft is carried, eliminating edge compression.

 

5. The tooth end of the outer tooth sleeve is in the shape of a horn, which makes it very convenient to assemble and disassemble the inner and outer teeth.

 

Because the tooth surface of the outer teeth is a drum-shaped surface, the gap between the inner and outer teeth is reduced, the impact of the inner and outer teeth is small during work, and the service life is extended.



Inspection method of drum gear coupling




1. Check the meshing of the tooth surface of the drum gear 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 not have severe pitting, wear and cracks.

 

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

 

3. If you need to remove the ring gear, you must use special tools, not to beat, so as not to bend or damage the shaft. When reinstalling, the ring gear should be heated to about 200°C and then installed on the shaft. The interference between the outer ring gear and the shaft is generally 0.01~0.03mm.

 

4. When reloading the indirect tube or other parts, it should be assembled according to the original mark and data.

 

5. Use a torque wrench to tighten the bolts evenly.

 

 

Common failures of drum gear couplings


Regardless of the many advantages of the toothed coupling itself, it is difficult to avoid various size failures in long-term work and use. Some common obstacles in use of the drum gear coupling introduced to you below

 

1. The tooth surface of the coupling is seriously damaged, caused by poor materials and low hardness of the tooth surface.

 

2. The axial displacement of the gear ring of the coupling is large, and it can't even mesh. The tooth shape design is not reasonable enough, the tooth tip interference or the machining accuracy is not high.

 

3. The coupling has broken teeth.

 

4. The coupling bolt breaks.

 

5. The over-installation and over-installation cause the tooth clearance to disappear.

 

6. Unclean oil, insufficient lubrication or dry grinding

 

Measures to solve the fault of drum gear couplings

 

1. The oil quantity of the lifting parts coupling is insufficient or lacks oil

 

Treatment method: As long as the new grease is replaced, qualified grease oil is injected regularly to prevent oil leakage and the amount of oil is sufficient to avoid

 

2. The horizontal and coaxial errors of the two shafts are too large, which exceeds the range of the coupling, which can make the shaft teeth and internal teeth mesh inaccurately, causing local contact and causing additional torque.

  

Treatment method: The horizontal and concentricity errors of the two shafts are large, which causes the coupling to be uncomfortable when rolling. This kind of failure is difficult to handle and needs to be discontinued. That is, re-align, or re-align the reducer side, or re-align the reel side. First find out the position where the offset error is large, so first measure the coupling is offset to that side, that is, measure the horizontality and coaxiality of the main shaft and the horizontality and coaxiality of the main shaft of the reducer. Scale leveling to correct, you can eliminate the fault.

 

Development of drum gear coupling

 

The reason for the wear of the coupling gear of the above lifting accessories is basically similar. In addition to the normal force, the connecting bolt is also subjected to additional bending moments, which causes it to break, which is the main reason. This kind of reason mostly occurs when the level difference between the reducer main shaft and the horizontal is large. Furthermore, the bolt diameter is small, the strength is not enough or the bolt material is poor, it can also cause the bolt to break.

 

With the rapid development of modern industrial technology, the technical and economic indicators such as the bearing capacity, reliability, efficiency, circumferential speed, volume and weight of drum gear couplings are increasingly demanding. Mainly reflected in the following aspects:

1. Among the full range of couplings, the drum-shaped gear coupling has small size, large transmission torque, strong ability to absorb connection errors, and the well has excellent performance characteristics;

 

2. In the medium and heavy machinery industry, the drum gear coupling is a common component that connects the two transmission shafts;

 

3. Drum gear coupling is developed on the basis of straight-tooth gear coupling to meet the performance and other technologies;

 

4. Drum gear coupling also plays an important role in production practice, it can compensate the angular error, axial and radial installation errors caused by the misalignment of the two coupling shafts, allowing the two shafts There is a certain displacement

 

5. With the development of economy and the rise of heavy machinery and equipment, the requirements for the use of high-precision drum-type gear couplings for its main transmission are also increasing.





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