The development trend of drum gear coupling
Drum gear coupling is a new type of gear coupling developed on the basis of spur gear coupling and digesting and absorbing foreign advanced technology. It is composed of an outer gear sleeve with a drum-shaped tooth thickness and a matching inner gear ring that connects two shafts. It is suitable for heavy load and two-axis transmission that requires axis displacement compensation.
Under normal circumstances, it is required that the two shafts to be connected are completely concentric, and it is impossible to continue to maintain the concentric state during operation. Because of installation errors, bearing wear, force deformation, foundation sinking, etc., the axis produces radial and Angular displacement. The drum gear coupling has the characteristics of compensating the above displacement, reduces the additional load caused by the axis displacement, improves the working stability and reliability of the transmission device, and thus prolongs the service life of the transmission device.
In recent years, drum gear couplings in many industries in our country have been widely used, from high-speed turbine units to medium and low-speed heavy metallurgy, mining, lifting and transportation equipment, and a large number of applications have also formed their own standard series. We have also accumulated rich experience in manufacturing.
1. The technical level and status of the product
Drum-shaped gear couplings in our country have caught up with foreign standards in terms of product specifications, performance parameters, and manufacturing accuracy.
1.1 The main parameters of the product standard
Abroad: The standard series of German FLENDER company: the maximum turning diameter is 1710mm; the nominal maximum torque is 4030kN.m.
Standard series of German TACKE company: its maximum turning diameter is 1760mm; nominal torque is 3550kN.m.
Japan Mitsubishi Corporation standard series: its maximum turning diameter is 1644mm; nominal torque is 4400kN.m.
National professional standards were formulated in the 1980s in my country:
ZBJ 19012-89, ZBJ 19013-89, ZBJ 19014-89, now revised as: JB/T 8854.1-2001, JB/T 8854.2-2001, JB/T 8854.3-2001; its maximum turning diameter is 1644mm; nominal torque is 4500kN .m.
1.2 The radius of curvature of the tooth surface and the tooth engagement angle that affect the contact strength
The bearing capacity and life of the drum gear coupling depend on the contact strength, while the tooth surface curvature radius and tooth engagement angle directly affect the contact strength. The following is the relationship between the tooth engagement angle and the radius of curvature and the contact strength:
—Contact stress F—Circumferential force borne by the gear
E—material elastic modulus—radius of curvature of tooth surface
—Displacement circle radius —Meshing angle
—Meshing height of internal and external teeth
From the above formula, we can see that the radius of curvature of the tooth surface and the tooth engagement angle directly affect the contact stress. The smaller the engagement angle, the larger the radius of curvature, and the larger the radius of curvature, the smaller the contact stress.
The meshing angles of drum gear couplings abroad are 20°, 21.5°, 28°, and 30°.
We choose 20° meshing angle, which is beneficial to reduce contact stress.
1.3 Manufacturing technology
Drum-shaped gear bushing tooth profile processing, from manual, electric pulse, hydraulic profiling to comprehensive CNC processing in China, the precision can fully meet the design requirements.
Nitriding treatment can be carried out when hard tooth surface is required, or high-quality low-carbon alloy steel can be used for carburizing and quenching and grinding or scraping with an alloy knife to meet the design requirements.
2. Development trends at home and abroad
With the continuous development of technology, more and more drum-shaped gear couplings require high-precision, heavy-duty hard tooth surface.
In foreign countries, the main parts of the heavy-duty high-precision drum gear coupling are made of low-carbon alloy high-quality steel, which is milled and ground after heat treatment with high machining accuracy. The depth of the heat-treated carburized layer is guaranteed by numerical control equipment.
The drum-shaped gear coupling used by SMS company in the main transmission machinery of the rolling mill, the main material is 15Cr2Ni2 or 17 Cr2Ni2Mo, and the tooth surface is ground. From the above two perspectives, the development of the hard-toothed drum gear coupling requires us to further enrich the manufacturing process and equipment.
The requirement for the interchangeability of the main parts of the drum gear coupling is worthy of our attention: in foreign countries, each part of the drum gear coupling can be interchanged. If one of them is damaged, it can be replaced with a single spare part. , No need for overall replacement, which saves maintenance time and is convenient for users.
In my country, the drum-shaped teeth with hard tooth surfaces are generally treated by nitriding. The hardened layer has a small service life and is not ideal. In recent years, the Erzhong Group Corporation and the Erzhong Basic Parts Factory have successfully developed carburized and ground Hard tooth surface drum-shaped gear coupling, the product is used by Baosteel, Tianjin Steel Pipe Company, etc.
The problem of parts interchange: Due to the manufacturing cost, we use CNC machine tools to meet the requirements of users, but from the perspective of the development situation in the future, the interchangeability of product parts should be guaranteed regardless of whether users require it or not. .
3. Production and sales status and market forecast
In the 1980s, it began to develop drum gear couplings and formulated national professional standards and machinery industry standards. It has been nearly 20 years since its publication and implementation. It has basically replaced the original spur gear couplings because of its compact structure and load-bearing capacity. Large, small moment of inertia, and a certain axis offset compensation performance, so it is widely used in various mechanical transmissions, and the coupling itself is a vulnerable part, which needs to be replaced every 1 to 2 years, so the market needs The volume is large. The annual sales of drum-shaped gear couplings in Deyang alone are more than 10 million yuan. It is estimated that the domestic machinery, metallurgy, and heavy lifting and transportation will require no less than 100 million yuan each year. We hope that all manufacturers will increase their technical investment. , Update equipment, produce drum-shaped gear couplings as soon as possible in the market, and make due contributions to my country’s technological development