How to distinguish the authenticity of a slewing bearing from its appearance?

Fake goods are a hateful existence for all walks of life. Many fake and inferior products carry the same outer packaging as the regular brand, but they are among the failures of Jinyu. Not only the product quality cannot be guaranteed, but it may even be in use. During the process, the maintenance and shutdown of the machine caused unpredictable economic losses. So how should we distinguish the true and false of the slewing ring from the appearance when we buy the slewing ring every day? The editor is here today.

First, eight counterfeit methods of slewing ring

Slewing Bearings

1. Material fraud: use iron or carbon steel to make slewing bearings, or repair scrap bearings. The former will cause insufficient hardness of the bearing, and the latter will cause insufficient bearing accuracy. Once these slewing bearings are used on bearings that require high accuracy and bearing hardness, they can easily cause machine failures.

2. Falsified outer packaging: Brand the inferior slewing ring or bearing produced by a small factory with the trademark of a large manufacturer, and counterfeit the inner and outer packaging and the certificate of conformity of the large-brand product. In this way, you can use the brand influence of major manufacturers to broaden the sales of your products.

3. Falsified sales channels: users, distributors, agents, or even counterfeit manufacturers’ spot sales outlets of well-known brands. Let consumers not be able to judge true and false, and make wrong judgments.

4. Pretend to be inferior: use inferior bearings as bearings. In the production process of bearings, defective products will be more or less produced, and they will generally be scrapped. Some black-hearted businesses will pretend to be defective products for sale, but the quality of the products is difficult to guarantee.

5. Accuracy fraud: use ordinary bearings to pretend to be high-precision bearings. Precision bearings have different requirements for the accuracy of various parts during production. Compared with ordinary bearings, the requirements will be relaxed. This way, the common means of posing as precision slewing bearings is also very abhorrent.

6. Fake goods for sale: slewing bearings are usually purchased in large quantities when they are sold. Some merchants take advantage of the buyer’s mentality that they will not check one by one, and sell them together with fake goods, and the product quality will vary. There is a bad situation.

7. Price fraud: In order to increase profits, businesses sell fake goods at high prices and use fake prices.

8. Look at people to deliver goods: When selling slewing bearings, merchants will provide selective supplies according to the seller’s specific conditions. If buyers want cheap goods, they will give fake goods. If they want good quality, they will give genuine goods. I don’t know how to do it. Those who only bargain think that they are taking advantage of it, but they don’t know that they may buy fakes.

Second, the method of identifying the true and false from the appearance of the slewing ring

Slewing Bearings

1. Look at the clarity of the stamp

How to distinguish the authenticity of a slewing bearing from its appearance? Each bearing product will have its brand name, label, etc. printed on the bearing product body. Although the fonts are very small, the products produced by regular manufacturers are printed with steel stamping technology, and they are pressed before heat treatment. Therefore, although the fonts are small, they are deeply recessed and very clear. Normally, the fonts of counterfeit products are not only blurred. Due to the rough printing technology, the fonts float on the surface, and some of them can even be easily erased by hand or have serious manual traces.

2. Listen to the noise inside the bearing

Hold the inner sleeve of the bearing with your left hand, and turn the outer sleeve with your right hand to make it rotate slightly. Listen for noise during the operation of the bearing. Due to the backward production conditions of most counterfeit products and the purely hand-made workshop operation, the bearing body will inevitably be mixed with impurities such as dust and sand during the production process. Therefore, noise or unsmooth operation may occur when the bearing rotates. phenomenon. This is the key to judging whether the product comes from a regular manufacturer’s brand product that has strict production standards and is operated by a machine.

3. See if the surface is clean

Whether there are turbid oil stains on the surface, we should pay special attention to it when buying imported bearings. Since there is still a certain gap between domestic anti-rust technology and foreign advanced manufacturing countries, it is easy to leave thick oil marks when anti-rust treatment on the bearing body, which feels sticky and sticky when touched by hand, while foreign original There is almost no trace of anti-rust oil on the imported bearings. According to industry insiders, particularly careful people can smell a special smell on imported bearings, which is the smell of anti-rust oil.

4. Look at the chamfer

Whether the chamfer of the slewing ring is produced is also closely related to the production technology level of the bearing manufacturer. Therefore, the neat degree of the chamfer can judge the technological level of the bearing. The so-called chamfer of the bearing is the junction of the horizontal plane and the vertical plane. Due to the limitation of production technology, the counterfeit bearing products are not handled satisfactorily at these corners, which we can easily distinguish.

5. Look at the packaging of the bearing

The packaging is divided into inner packaging and outer packaging. After the bearings are manufactured and passed the inspection, they will be cleaned and anti-rust treated, and then placed in the inner packaging to achieve waterproof, moisture-proof, dust-proof, shock-proof, and maintain the quality and accuracy of the bearing And the purpose of facilitating use and sales.

The inner packaging of the bearing is divided into three categories according to the anti-rust period:

(1) Short anti-rust period packaging: The anti-rust period is 3 to 6 months, which is suitable for bearings that are shipped to the same subscriber in large quantities and put into use in a short period of time. The two parties have agreed to use simple packaging based on the principle of ease of use.

(2) General anti-rust period packaging: one year anti-rust period, suitable for general-purpose bearings.

(3) Long anti-rust period packaging: two years anti-rust period, suitable for special and precision bearings.

The inner packaging materials of the bearing include polyethylene plastic tube (box), kraft paper, plain and wrinkled polyethylene composite paper, paper box, polyethylene or polyethylene plastic film, nylon fastening tape or plastic woven fastening tape, waterproof high-strength plastic tape , Burlap bags, etc. All of the above materials need to ensure that the corrosion resistance test of the material is qualified.

How to distinguish the true and false of the slewing ring from the appearance can be judged from the above aspects. In addition, you can judge the approximate price range based on the understanding of the bearing and the market situation of the bearing. As long as you are not greedy and bargaining excessively, you can also confirm the place of purchase. It is difficult to distinguish true from false sources through informal sources, and bearings can basically be bought. The slewing bearings produced by our Kuoyi Longda Bearing Co., Ltd. are all qualified products that have passed quality inspections. If you have any needs, please feel free to inquire.

What are the installation methods of the spur gear slewing drive? And installation precautions

Spur gear slewing drive is a rotary drive. Due to the different types of drive teeth, it can be divided into straight-tooth rotary drive and helical-tooth drive, both of which are full-circle rotary drive reduction transmission mechanisms that inherit the driving power source. The previous article has already introduced the difference between the spur gear drive and the slew drive. I will not introduce it in detail here. Today, the Lunda bearing manufacturer will give a brief introduction on the installation methods of the spur gear drive. I hope it will be helpful to everyone.

Installation method of spur gear drive

1. Fixed installation with solid shaft

This installation method is to connect the output shaft driven by the spur gear with the metallurgical machinery through couplings, sprockets, gears, pulleys, etc., and the spur gear drives the bottom anchor bolts to firmly install the spur gear drive on the structure On a solid, vibration-free foundation. At present, most spur gear drives can adopt this installation method.

For large spur gear drives, threaded holes should be machined on the body feet to adjust the installation position with adjusting bolts; for the spur gear drive of the luffing mechanism, pins should also be used for locking to prevent movement during installation .

2. Single-point floating installation of hollow shaft

This installation method uses the output shaft driven by the spur gear as a hollow shaft and is connected to the transmission shaft of the working machine through an expansion sleeve. The entire driving device, including the motor, coupling, brake, and reducer, is installed on the support of the transmission device. Seat, and then supported by a ball hinge or bearing.
The installation principle is that the bearing point of the spherical hinge deviates from the center of gravity of the transmission device by a certain distance. In the working state, the bending moment caused by the eccentricity of the support point can be balanced with the bending moment caused by the load of the driving device. Therefore, the transmission shaft is not affected by the theory. Additional force.

3. Hollow shaft suspension installation

In this installation method, the output shaft driven by the spur gear and the metallurgical machinery shaft are connected by an expansion sleeve, and the support is completed by the output shaft and another torsion rod. This installation method is relatively simple, saves floor space, and can reduce the weight of the whole machine, and is suitable for transmission devices that transmit power from a vertical direction.

Spur gear drive installation is a delicate and complex task with high technical requirements. The operating procedures and design data must be strictly observed during operation. The general installation sequence is: equipment leveling and alignment, cleaning and assembly, adjustment and trial operation.

After understanding the installation methods of spur gear drives, the spur gear drive manufacturers will introduce some precautions in the installation of spur gear drives. I hope it will be helpful to everyone.

Precautions for installation of spur gear drive

WE Series Slewing Drive

1. Cleaning and inspection: clean the spur gear drive installation shaft before installation and use, and check whether the installation shaft is bruised or dirty. When the spur gear drive is installed in an inclined manner, ensure that the high position of the gear shaft bearing is lubricated by the gear oil in the box, and ensure that the gas in the box can be discharged from the high position of the box.

2. Keep the mating interface flat: When assembling the spur gear drive with the actuator and the prime mover, the connecting flange should be cleaned and polished to ensure the flatness of the connecting part of the connecting flange, to ensure that it is flush, and all bolts on the flange circumference should be matched. , Fastening.

3. Keep balance: The assembled transmission components (couplings, sprocket) should be kept in rotation balance, so as not to cause impermissible radial force or axial force. The internal thread of the assembly fixture and the shaft end is usually used, and the transmission part is pressed in with a bolt, otherwise it may cause damage to the internal parts of the spur gear drive.

4. Do a good job of leveling: The spur gear drive installation must be rigidly fixed on a solid horizontal foundation or a vertical frame, and the leveling must be done. It is necessary to ensure that the coaxiality of the prime mover, coupling, spur gear drive, and actuator is consistent, so as to avoid additional stress on the input and output shafts and bearings of the equipment and cause damage to the equipment input and output shafts and bearings.

5. Control the shaft gap: the coaxiality of the two connected shaft extensions should be controlled within the range of φ0.1mm, and there should be a gap of 2-8mm between the end faces of the two shaft extensions. The value of the gap depends on the specific equipment connected to the spur gear drive. Depending on the situation, it is necessary to ensure sufficient load transfer capacity and to ensure that the bearings driven by the spur gear are not subject to additional axial force.

6. Add gear oil: The grade of oil should be the spur gear drive value, or the oil equivalent to the oil should be used. And the amount of oil must be correct, and each spur gear drive has a sign with the grade and quantity of oil attached. The oil mirror is a display mirror of the oil level driven by the spur gear. On the side of the spur gear drive, the oil level should reach the upper and lower positions of the middle of the oil mirror when filling oil.

Spur gear drive lubrication and oil injection method

The lubrication effect has a great influence on the spur gear drive. If the lubrication conditions are not good, the heat generated by the spur gear drive will increase and its carrying capacity will decrease. Therefore, the lubricating oil and the amount of oil must be selected correctly to effectively ensure the normal operation of the spur gear drive transmission and prolong its service life.

Under normal circumstances, the lubrication method adopts oil pool lubrication and natural cooling; and for high-power spur gear drive or insufficient thermal power, pressure circulating oil lubrication or additional cooling devices can be used for cooling.

Under normal operating conditions, when the ambient temperature is (0~35)℃, or using circulating oil lubrication, choose medium-duty industrial gear oil 220#; when the ambient temperature is (35~50)℃, it is recommended to select medium-load Industrial gear oil 320#. In addition, the spur gear drive should be replaced with lubricating oil after the first 400 hours of operation.

What are the installation methods of spur gear drive? I believe you already know it. During installation, you can choose a suitable installation method according to the specific conditions of the machine to which the spur gear drive is adapted. Of course, some precautions during the installation process have been introduced by the spur gear drive manufacturer. Up. In addition, if you have any questions about the installation or use of other spur gear drives, you can call us Longda Bearings, and welcome your calls.

Process flow and processing method of spur drive gear processing

Spur gear drive is a kind of gear reducer we often say. It is divided into spur gear and helical gear. Its working principle is mainly a reduction gear that drives the ring gear of the rotary drive to rotate through the pinion gear. So how much do you know about the technological process of gear processing for devices that use gears to complete the deceleration work? The following drive manufacturers will introduce to you the processing process and tooth profile processing methods of spur drive gears.

Machining process of spur drive gear

The processing process of spur drive gear includes: forging blank, normalizing, turning processing, gear shaving, hobbing, gear shaping, grinding processing, heat treatment, and trimming. The specific processes are as follows.

1. Forging billet

In recent years, hot die forging has been widely promoted in shaft processing, and is suitable for making blanks for more complex stepped shafts. It not only has high precision, small subsequent machining allowances, and high production efficiency.

Slewing Drive

2. Normalizing

The purpose of the normalizing process is to obtain a hardness suitable for subsequent gear cutting to reduce deformation. The material of the gear steel used is usually 20CrMnTi. The process is affected by factors such as equipment, environment, and workpiece cooling rate, and the hardness dispersion is large.

3. Turning

In order to meet the high-precision positioning requirements of gears, CNC lathes are used for gear blank processing to maintain the verticality requirements of the end face, outer diameter, and bore diameter, which can improve the precision of the gear blank and improve work efficiency.

4. Shaving

Radial gear shaving technology is widely used in the production of high-volume automobile gears due to its high efficiency, design tooth profile, and easy realization of tooth profile modification requirements.

5. Rolling and shaping

Common gear hobbing machines and gear shaping machines are still widely used for processing gears. Although it is easy to adjust and maintain, the production efficiency is low. If a large capacity is completed, multiple machines are required to produce at the same time. With the development of coating technology, the re-coating after sharpening of hobs and inserts is very convenient. Coated tools can significantly increase the service life, generally by more than 90%, effectively reducing the number of tool changes And sharpening time, the benefit is significant.

6. Grinding

It is mainly to finish the heat-treated gear inner hole, end face, shaft outer diameter and other parts to improve the dimensional accuracy and reduce the form and position tolerance. The gear processing technology adopts the pitch circle fixture to position and clamp, which can effectively ensure the processing accuracy of the tooth part and the installation datum, and obtain satisfactory product quality.

7. Heat treatment

Gears require carburizing and quenching to ensure good mechanical properties. For products that no longer need to be ground after being heated, stable and reliable heat treatment equipment is essential.

8. Trimming

This is the inspection and cleaning of the bumps and burrs of the gears before assembly of the transmission and gear drive to eliminate the abnormal noise caused by them after assembly. It is completed by listening to the sound of a single pair of meshing or observing the meshing deviation on a comprehensive inspection instrument.

SG-I Spur Gear Slewing Drive

Machining method of spur drive gear

The choice of spur drive tooth profile processing method mainly depends on the gear’s accuracy grade, structural shape, production type and production conditions. For gears of different accuracy grades, the commonly used tooth profile processing methods are as follows.

1. Gears below grade 8 accuracy

Hardened and tempered gears can meet the requirements with gear hobbing or gear shaping. For hardened gears, a machining plan of rolling (shaping) teeth-tooth end processing-quenching-correction hole can be used. However, the machining accuracy of the tooth profile should be improved by one level before quenching.

SG-H Spur Gear Slewing Drive

2. 6-7 grade precision gear

For hardened gears, the following can be used: rough hobbing-fine hobbing-tooth end machining-fine shaving-surface hardening-calibration reference-honing.

3. Gears with accuracy above grade 5

Generally used: rough gear hobbing-fine gear hobbing-tooth end machining-quenching-calibration standard-rough grinding gear-fine grinding gear. Gear grinding is currently a high-precision machining method in tooth profile machining with a small surface roughness value, and the accuracy can be as high as 3-4.

The above is the introduction about the processing process and processing methods of the spur drive gear. I hope it can help everyone to have a certain understanding of the processing of the drive gear.

What are the repair processes for slewing bearings?

The slewing bearing is also called the slewing ring. It is a new type of mechanical parts. It is composed of inner and outer rings, rolling elements, etc. The slewing ring is a large-scale bearing that can withstand comprehensive loads, and can withstand larger axial and diameter at the same time. Bearing for load and overturning moment.

Generally, it is widely used in industry, and the effect of use is very good. The application of slewing bearings is special, and it must be operated under continuous shock, vibration, and overload. Therefore, the control of production technical parameters in the product manufacturing process is also It is more rigorous, with high bonding strength, no shedding, no hard spots, high surface finish, and adjustable hardness. However, damage is still inevitable, which requires special repair techniques to ensure the flexibility of the later application of the slewing ring.

Repair process of slewing bearing

Slewing Bearings

1. Low temperature iron plating method

Low-temperature iron plating is a commonly used method for repairing shaft parts in the industry, and it has a long history of application in other mechanical maintenance industries. Low-temperature iron plating is an electroplating technology with a fast iron plating speed. The one-time iron plating has a large thickness, a relatively mature process and high production efficiency. It is suitable for repairing the surface of agricultural machinery transmission shafts or parts.

2. Thermal spraying method

Thermal spraying method mainly uses high-speed airflow to spray molten metal material on the surface of partially worn parts, and then the size can be restored after processing. Thermal spraying technology includes many methods such as flame spraying, electric spraying and plasma spraying. The additional materials for spraying are often better than the raw materials, so after the slewing bearing is repaired, the parts in terms of wear resistance and corrosion resistance have been greatly improved.

ceshi

3. Surfacing method

The surfacing method is to use the welding process to surfacing a layer of welding material on the worn parts of the part, and then restore the original matching size of the part through mechanical processing. The surfacing process can achieve different material repair effects through the selection of welding rods or wires. The process has the advantages of high material strength after repair and faster repair speed, and is suitable for repairing parts with greater wear.

The performance of the correctly repaired bearing is equivalent to that of the new bearing, and all parameters such as clearance can meet the requirements of use. It is important to understand and identify the degree of damage to choose the correct repair plan. Bearing repair requires long-term technical accumulation and comprehensive basic data storage. Professionally trained personnel can judge whether the bearing needs to be repaired. Timely routine inspections, preventive maintenance and vibration analysis can grasp the appropriate repair time in time, so as to help companies economically repair damaged bearings.

Inventory of common slewing bearing damage failure causes analysis and solutions

It is common for bearings to fail during operation, so there is no need to make a fuss. In the event of a failure, the key to determining the cause of the damage and handling it Today, the editor has counted some common slewing bearing damage failure causes analysis and solutions.

 Crack defects

Trouble phenomenon: partly notched and cracked.

1. The cause of the failure

①Excessive impact load; ②Excessive interference; ③Large peeling; ④Friction cracks; ⑤Poor accuracy of the installation side (too large corner round); ⑥Poor use (a copper hammer is used to insert large foreign objects).

2. Solutions

①Check the conditions of use; ②Set appropriate interference and check materials; ③Improve installation and use methods; ④Prevent friction cracks (check lubricant); ⑤Check the design around the bearing.

Rotation of slewing bearing is not flexible

Trouble phenomenon: bearing heating, jitter, stuck.

1. The cause of the failure

①The clearance is too small (including the clearance of the deformed part); ②Insufficient lubrication or improper lubricant; ③Excessive load (excessive preload); ④The roller is skewed.

Slewing Bearings

2. Solutions

①Set proper clearance (increase the clearance); ②Check the type of lubricant to ensure the amount of injection; ③Check the conditions of use; ④Prevent positioning errors; ⑤Check the design around the bearing (including heating of the bearing).

The hardness layer falls off

Trouble phenomenon: the running surface is peeled off, and it is obviously convex and concave after peeling off.

1. Reason

①Improper use due to excessive load; ②Poor installation; ③Poor precision of shaft or bearing box; ④Too small clearance; ⑤Intrusion of foreign matter; ⑥rusting; ⑦Hardness reduction caused by abnormal high temperature

2. Solutions

①Re-study the operating conditions; ②Re-select the bearing; ③Reconsider the clearance; ④Check the machining accuracy of the shaft and the bearing housing; ⑤Research the design around the bearing; ⑥Check the installation method; ⑦Check the lubricant and lubrication method.

Slewing Bearings

Scratches and jams

Trouble phenomenon: rough surface, accompanied by micro-dissolving; scratches between ring ribs and roller end faces are called jams

1. Reason

① Poor lubrication; ② Foreign matter intrusion; ③ Roller deflection caused by bearing tilt; ④ Oil breaking on rib surface caused by large axial load; ④ Surface roughness; ⑤ Large rolling element sliding.

2. Solutions

①Re-study lubricants and lubrication methods; ②Check the conditions of use; ③Set appropriate preload; ④Strengthen the sealing performance; ⑤Use the bearing normally.

The cage is damaged

Trouble phenomenon: loose or broken rivet, broken cage.

1. Reason

①Excessive torque load; ②High-speed rotation or frequent speed changes; ③Poor lubrication; ④Entrapped foreign objects; ⑤Large vibration; ⑥Poor installation (installation in tilted state); ⑦Abnormal temperature rise (resin cage).

2. Solutions

①Check the operating conditions; ②Check the lubrication conditions; ③Re-study the selection of the cage; ④Pay attention to the use of bearings; ⑤Study the rigidity of the shaft and the bearing box.

Rusty corrosion on the surface of the slewing bearing

Trouble phenomenon: Part or all of the surface is rusty, and it is rusty in the form of pitch of rolling elements.

1. Reason

①Poor storage condition; ②Improper packaging; ③Insufficient rust inhibitor; ④Intrusion of moisture, acid solution, etc.; ⑤Hold the bearing directly by hand.

2. Solutions

①Prevent rust during storage; ②Strengthen the sealing performance; ③Check the lubricating oil regularly; ④Pay attention to the use of bearings.

Abrasion

Trouble phenomenon: red rust-colored wear particles are produced on the mating surface.

1. Reason

①Insufficient interference; ②Small bearing swing angle; ③Insufficient lubrication (or in a non-lubricated state); ④Unstable load; ⑤Vibration during transportation.

2. Solutions

①Check the interference and lubricant coating status; ②The inner and outer rings are packaged separately during transportation, and pre-pressure is applied if they cannot be separated; ③Reselect the lubricant; ④Reselect the bearing.

Slewing Bearings

Wear

Phenomenon: Surface wear, resulting in dimensional changes, often accompanied by abrasion and wear marks

1. Reason

①The lubricant is mixed with foreign matter; ②The lubrication is poor; ③The roller is skewed.

2. Solutions

①Check lubricant and lubrication method; ②Strengthen sealing performance; ③Prevent positioning error.

Indentation bruises

Trouble phenomenon: surface pits caused by stuck solid foreign objects or impact and scratches caused by installation

1. Reason

①Intrusion of solid foreign matter; ②Insert the peeling sheet; ③Shock and fall off caused by poor installation; ④Install in an inclined state.

2. Solutions

①Improve the installation and use methods; ②Prevent foreign matter from entering; ③If it is caused by metal sheets, check other parts.

Electric erosion

Resolve the phenomenon: the rolling surface has a pit-like pit, and the further development is in a wave plate shape.

1. Reason

The rolling surface is energized.

2. Solutions

Make a current bypass valve; take insulation measures to prevent current from passing through the inside of the bearing.

The above is the explanation of the common slewing bearing damage failure phenomenon, the reason analysis and the solution measures. I hope everyone will be helpful after reading it. Analyzing the damage and failure forms of the slewing bearing can provide a detailed reference for the design and selection of the bearing, and then improve the design, rationally select the bearing, give full play to the function of the bearing, increase economic benefits, and increase the service life.

What is a slewing drive? Classification and application of slewing drive

The rotary reducer is a rotary reducer with integrated driving power source. The rotary bearing is used as the main transmission part and the mechanism attachment. Its essence is a permanent magnet motor with large torque. This product is also called rotary reducer. Drive, compared with traditional rotary products, it has simple installation, easy maintenance, and saves installation space to a greater extent. It is mainly used in beam trucks, aerial work vehicles, industrial robots, photovoltaic power generation, wind power generation and construction machinery claws. Tools and other fields.

What is the slewing drive

Slewing Drive

1. Definition of slewing drive

The slewing drive device is also called a slewing reducer, a gear reducer, a turntable reducer, a slewing mechanism, and a slewing drive pair. They are all types of reducers that use slewing bearings as the main support, and the auxiliary drive source uses gears or worms as the driving parts, so as to realize the deceleration and full-circle slewing functions. The composition of the slewing drive mainly includes gears (or worms), slewing bearings, motors, housings, and bases. Slewing drive can be basically divided into single worm drive slewing drive, double worm drive slewing drive and special type of slewing drive.

2. Classification of slewing drives

Spur Gear Drive

(1) Classification according to transmission form

According to the variable transmission form of slewing drive, it can be divided into gear slewing drive and worm gear slewing drive, inheriting the characteristics of gear drive and worm gearing. These two slewing drives can be adapted to medium-high and low-speed applications respectively. In terms of carrying capacity, the performance of the worm gear type is better than that of the tooth type, and when the envelope worm transmission is adopted, its carrying capacity, anti-deformation ability and transmission rigidity are further improved, but the worm gear type rotary drive is more efficient in terms of efficiency. Inferior to the gear type slewing drive, the gear type slewing drive is divided into a straight tooth type slewing drive, a helical tooth type slewing drive, and a volute type slewing drive.

(2) Classification according to the openness of slewing drive

According to the openness of the slewing drive transmission mechanism, the slewing drive can be divided into open and closed. Generally, the open structure is mostly used in applications where the environment is too harsh and the maintenance and maintenance cycle is short. The open structure is more convenient for parts. The inspection, maintenance and maintenance of the product are also more convenient for replacement. However, the closed structure can provide a longer maintenance life cycle in occasions where the environmental conditions have not changed much and the environmental pollution level is below the medium level.

①Customized double-gear high-precision, negative-clearance precision helical (grinding) slewing drive, to achieve zero backlash for customers.

(3) Classification according to driving power

According to the structure operation type of the slewing drive, it can be divided into light slewing drive, medium slewing drive and heavy slewing drive. According to the slewing drive’s power, size, dead weight, and application in different fields and machines to achieve its own functions, the light-duty slewing drive is light in weight, and its load and deceleration capabilities are suitable for high-speed (≥10rpm), vibration, impact loads, etc. Working conditions: The medium-sized rotary drive is suitable for high-speed (≥10rpm), vibration, impact load and other working conditions, and the heavy-duty rotary drive is suitable for high-speed (≤3rpm), heavy-duty, and intermittent working conditions.

(4) Classification according to the drive composition structure

According to the composition of the driving device, it is divided into vertical drive and horizontal slewing drive. Vertical slewing drive means that the traction motor and the traveling wheel are vertical, and the traction motor is upright above the traveling wheel. It has the advantages of small gyration radius, high protection level, convenient maintenance, etc., but high manufacturing cost; horizontal drive means that the traction motor and the traveling wheel are parallel, and the traction motor is mostly coaxial with the traveling wheel and is horizontal. It has the advantages of compact structure, simplicity, and low installation height.

What is the slewing ring gear module?

Slewing bearing is one of the important parts of many modern machinery and equipment. It is called “joint of machine”. Many people are familiar with various parameters of slewing bearing, including clearance, inner and outer diameter, friction coefficient, etc. Many friends don’t know the module of supporting gear. The technical staff of Longda Bearing, a slewing bearing manufacturer, will give us a detailed introduction to this problem.

1. What is the module of slewing ring gear

The length of the arc (gear)/straight line (rack) occupied by a single gear tooth in the indexing circle (gear)/or line (rack), its length is π * m, and m is the modulus.

What does the module of the slewing ring represent: The module of the slewing ring represents the product of the tooth pitch and the number of teeth of the slewing ring gear, which is the circumference of the index circle. The gear modulus of the slewing ring determines the size of the tooth. The gear modulus is a basic parameter for the calculation of the gear size. The symbol is “m”. Gear cutters can be standardized, so that the standard modulus of gears can be standardized for mass production. Facilitate the replacement of later accessories. In the same way, “modulus” refers to the ratio of the pitch t between the tooth profiles of two adjacent gear teeth on the same side and the circumference ratio π (m=t/π), in millimeters.

If the number of teeth of the slewing ring gear is constant, the larger the gear modulus, the larger the radial dimension of the gear. The teeth of a gear with a large modulus are thick, and for two gears with the same number of teeth, the outer circle of the gear with a large modulus is larger. Therefore, the modulus of the gear in a watch is very small, and the modulus of the flywheel and transmission gear on the mechanical punching machine is large. The modulus of the two meshing gears must be the same. Modulus is the basic parameter of gear design, and it is used in many calculations of gear design.

Slewing Bearings

2. Reasonable selection of gear module

When designing a gear, one of the important parameters is this modulus. The gnawing of the gear will produce gnawing pulsation. The main reason is that it has a great relationship with the elastic deformation of the gear teeth. It is a basic part of the gear design. Parameter-gear modulus, if it is a relatively large modulus (that is, a gear with a relatively large size), it will also have a relatively large load-bearing capacity. The modulus parameter is inversely proportional to the degree of bending of the gear teeth. The increase of the modulus means that the rigidity of the gear teeth is improved, so that the elastic deformation of the gear teeth will not be great when the gnawing transmission is carried out, which greatly reduces the impact force formed by the gear teeth, thereby achieving The purpose is always greatly reduced. Therefore, from this point of view, the modulus should be increased appropriately, but the error generated when machining gears is also related to the modulus. If the modulus is increased, the tooth profile and pitch will also be increased. At this time, the error of gnawing noise will also increase accordingly, so the choice of modulus should be determined according to the specific situation.

Slewing Bearings

In the case of keeping the modulus unchanged, the diameter of the gear is proportional to the number of teeth, so the change of the number of teeth will also change the bending amount and elastic rigidity of the gear teeth: the strength of the noise generated by the sound source is not only related to the energy of the vibration source It is related to the size of the radiation area. If the radiation area is increased, the radiation power will also increase. Increasing the gear diameter will increase the noise radiation area, which will greatly affect the gear. Effective control of noise.

Therefore, in the relevant design, within the permissible range of ensuring the strength of the gear, the number of small teeth and the small modulus should be used as much as possible, and the reasonable selection of materials and heat treatment methods can be combined to promote the increase of the strength of the gear teeth, thereby reducing the diameter of the gear teeth. Then, the purpose of reducing gear noise is achieved.

What is the gear making process of slewing bearings

Gear processing is a time-consuming process in the production of slewing bearings, and it is also one of the main factors that have restricted the production efficiency of slewing bearings. Based on the actual machining data, the application of milling and hobbing processes in the processing of turntable bearing teeth is compared from the aspects of efficiency and cost, which provides a basis for the reasonable selection of turntable bearing teeth processing technology and equipment. Today, the editor will come to talk with you about the tooth-making process of slewing bearings.

1. Material selection of slewing bearing blank

Generally, 50Mn is used for the slewing bearing ring. After surface quenching, the raceway hardness is HRC55-62. However, sometimes 42CrMo is selected to meet the needs of the host for special applications, which has a higher hardness. LDB’s selection of blank suppliers has undergone strict screening and strictly follows the traceability procedure. For each blank, from receipt to finished product, it can trace the source of the blank according to its serial number, quality inspection and other whole-process data.

Slewing Bearings

2. The technology of making gears from slewing bearings

1. The equipment used in the gear processing department still uses a large number of ordinary gear hobbing machines and gear shaping machines. Although it is convenient to adjust and maintain, the production efficiency is low. If a large capacity is completed, multiple machines are required to produce at the same time. In order to solve the problem of low processing efficiency, while increasing the number of gear hobbing machines and gear shapers, high-speed gear milling machines are used, which has high processing efficiency and good surface finish quality.

2. Some slewing bearings used under severe conditions require surface quenching treatment, such as excavators, pile drivers, wood grabs, graders and other operating conditions, which have relatively large impact loads and require quenching treatment on the tooth surface. The hardness after quenching of several sizes is between 45-60HRC. For common working conditions such as cranes and tower cranes, the tooth surface does not need to be heat treated.

3. With the rapid development of Industry 4.0, slewing bearings are more and more widely used in the automation industry. In this application field, the accuracy requirements for the teeth are relatively high, and the low requirements are also 8 levels of accuracy. In response to the rapid changes in the market, during the construction of the new plant, higher accuracy requirements are required for the equipment to meet the market demand.

4. After the tooth-making process is completed, there are follow-up processes such as fine turning, plane, drilling, track grinding, and assembly, and the slewing bearing can be shipped out of the factory.

3. Introduction to the failure analysis of the slewing bearing gear

1. Improper adjustment of the backlash of the large and small gears during installation, which did not meet the requirements, resulting in poor meshing of the two gears during operation, resulting in broken teeth. The backlash should be adjusted strictly as required.

2. Failure to adjust the meshing gap with the pinion at the maximum position of the gear jump as required, causing the pinion to jam when meshing with the maximum gear jump position during operation, causing tooth breakage. The meshing adjustment should be carried out at the position painted with green paint and the pinion gear should be adjusted according to the requirements for trial operation.

3. The axes of the large and small gears are not parallel, and the large and small gears mesh poorly after installation, causing tooth breakage. It should be ensured that the axes of the two gears are parallel.

4. The mounting bolts are not fastened tightly, and the gears of large and small meshes are not well meshed, causing gear breakage. The bolts should be tightened as required.