Application of slewing bearing in CNC vertical lathe

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In the vertical turning equipment, the rotary table is one of the core structures that reflects the overall performance of the machine tool and realizes the machining accuracy of the workpiece. We require it to operate at high speed and bear heavier workpieces, while possessing precise running accuracy and very high anti-overturning moment capability. The slewing bearing supporting the worktable is the key to accomplish this important mission. Previously, most of the domestic workbenches chose thrust bearings and radial bearings to cooperate. This arrangement has a complicated structure and uses more materials. Especially when large box parts are placed, the space of the entire machine tool is larger. It is also difficult to install and adjust the pre-tightening of the slewing bearing, the alignment is more difficult to guarantee, and the overall accuracy of the worktable is difficult to improve.

Therefore, more designs are now beginning to choose cross-roller bearings with a more compact structure, which not only saves material costs, but also simplifies the design, higher limit speed, better operating accuracy and stability, and stronger load-bearing capacity and rigidity. This article introduces how to apply cross roller bearings on vertical lathes to achieve their perfect engineering performance.

1. Runout accuracy

Bearing runout can be divided into synchronous runout and asynchronous runout. The impact of synchronous runout on the overall runout of the workbench can be minimized by grinding the work surface, but the impact of asynchronous runout cannot be eliminated in this link. It is mainly It is determined by the outer diameter tolerance and roundness of the roller. Therefore, the better the asynchronous runout control of the bearing, the smaller the final radial and axial runout of the worktable, that is, the higher the running accuracy. When selecting bearing brands and accuracy grades, it is recommended not to only focus on the bearing assembly runout, but to have a thorough understanding of the accuracy standards that affect the asynchronous runout of the bearing.

2. Bearing fit

When selecting the bearing, it is recommended that the inner ring and the shaft, and the outer ring and the gear ring are tightly fitted. Since the outer ring is a rotating part, the tight fitting amount should be slightly larger. The inner ring will be pressed down by the end cap and adjusted to a certain pre-tightening amount, so the tight fitting amount should be slightly smaller. However, if the inner ring is considered to be a static part, and the inner ring and the shaft are designed to be loosely fitted, there is a radial gap between the inner ring and the shaft, it is possible that the inner ring may be deflected when the inner ring is installed, locked or the bearing is loaded. Oblique, that is, eccentricity occurs. This eccentricity will cause stress concentration on the boundary of the contact area between the roller and the raceway, causing serious scratches, cratering and peeling, and ending the bearing life earlier.

Three, shape and position tolerance

The mounting surface of the shaft and the gear ring is required to have the same flatness, perpendicularity, roundness and cylindricity as the precision bearing. Controlling these shape and position tolerances can not only achieve better assembly accuracy, but also avoid excessive eccentricity of the inner and outer rings of the bearing to cause stress concentration, and extend the service life of the bearing. Regarding the processing standards of the form and position tolerances, it is recommended to consult the bearing supplier and match its bearing accuracy.

Fourth, the axial preload

In the cutting test of the vertical turning, the end face and the outer circle roughness of the workpiece are very concerned, and one of the keys to determine the advantages and disadvantages is the rigidity of the system. The system rigidity includes the rigidity of the frame structure, the rigidity of the supporting bearing, etc. The rigidity of the bearing often depends on its axial preload.

Therefore, it is particularly important to fully consider the effects of temperature and load and reasonably set the axial preload of the bearing.

Analysis on the Causes of the Failure of Bucket Wheel Machine slewing bearing

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Slewing Bearing
Bucket wheel machine is an important production equipment that needs to be used during the transportation and loading and unloading of bulk cargo such as coal. The main purpose is to take materials from the storage yard. It is mainly composed of cantilever arm frame structure, mast structure, counterweight beam structure, cart structure, slewing mechanism, luffing mechanism, and walking mechanism. The slewing support is mainly used to support the upper structure of the bucket wheel reclaimer. The key component of bucket wheel reclaimer rotation work. In the internal structure of the bucket wheel reclaimer, the slewing bearing occupies a large part of the area. Because of its large volume and located at the upper and lower joints of the bucket wheel machine, the failure rate is high during the working process. Today, the editor will analyze the reasons for the failure of the bucket wheel slewing ring.

1. The main failure of bucket wheel reclaimer slewing bearing

Common failures of bucket wheel slewing ring can be summarized into two categories

1. The first category is caused by improper design, manufacturing and installation.

2. The other category is acquired problems caused by improper operation, use, and maintenance after production. The problems caused by acquired problems account for a larger proportion.

Bucket wheel slewing ring

2. The cause of the failure

1. In the manufacturing and processing of bucket wheel machines, in order to save processing and material costs, there is a problem that the main shaft is too thin, which causes the large shaft to easily break at the diameter of the driving wheel. In the processing of bucket teeth, manganese steel plates are used, which directly leads to the reduction of the service life of bucket teeth to one year.

2. If the installation is not in place, it will directly lead to the frequent tearing of the cantilever belt of the rotating mechanism, damage to the roller deflection of the walking device and other faults, which brings safety risks to the safe and stable operation of the equipment.

3. During the running-in period of the slewing ring, the lubrication status is poor, and frequent full-load work results in poor running-in of the raceway and rolling element pairs, which is manifested in the early excessive wear and fatigue pitting.

4. Fatigue type failure is a common failure of slewing bearing failure. When the rolling element and the raceway are under load and are in relative motion at the same time, under the action of this alternating load, the internal micro-cracks gradually expand to the surface and form flaking. Fatigue spalling will cause shocks during the operation of the slewing ring, aggravating vibration and noise.

5. The rolling elements are worn and broken, and the raceway is seriously deformed. Under the action of instantaneous large load, the raceway is locally deformed, which directly causes the wear, deformation and even rupture of the rolling elements, thereby causing the slewing ring to fail.

6. ​​The slewing bearing fixing bolts are installed too loosely, and they vibrate and disappear in the budding state during operation.

The above is a simple analysis of the cause of the failure of the bucket wheel slewing ring. For bucket turbines, once the slewing ring fails, the entire equipment can only be stopped, which affects the entire reclaiming process of the yard and causes greater economic losses. Therefore, we must analyze the common failure causes of the bucket wheel slewing ring operation, and study effective countermeasures to reduce the sudden failure of the slewing ring causing the bucket wheel to stop abnormally.

How to ensure the safe operation of single-row ball slewing ring? Four main points

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Single-row ball slewing ring is one of the important parts of modern machinery and equipment, mainly composed of upper ring, lower ring and full ball. Its operating speed is very low, and it is usually used in many mechanical products, such as widely used in rotating equipment such as rotary conveyors, excavators, construction machinery, and small and medium-sized cranes. The safe operation of the single-row ball slewing bearing is very important, and it directly affects the working efficiency of the unloading equipment. So, how to ensure the safe operation of single-row ball slewing ring? Next, let’s follow the editor to understand it.

1. Choose a slewing bearing of good quality

Single-row ball slewing ring is an important part of the machine. And because the components are affected by factors such as the environment and the load during work, they can be regarded as consumables. We need to buy it frequently to maintain the normal operation of the machine. In this regard, we can start from the brand. If the machine itself is a well-known brand product, buy parts of the same brand. Because each brand uses different alloy formulations, there are subtle differences. When brands obsolete products, natural compatibility is yes. Next, buy a single-row ball slewing bearing, please pay attention to the toughness of the product. Because the parts are thin, many parts look good, but they are compensated after being placed on the machine for a long time. Actually choose, you can buy more brands in practice.

2. Timely lubrication work

is in daily operation. After working for a while, you should pay attention to its operating status. You can add some protective oil from time to time to effectively extend its service life.
Single volleyball slewing ring
Three, choose labyrinth ring seal

The sealing of the single-row ball slewing bearing is to prevent grease leakage and filling on the one hand, and on the other hand to prevent external dust, impurities and moisture from entering the bearing and affecting normal operation. Since single-row ball bearings mainly work in heavy load and low-speed work, the seal ring has two structures: rubber ring and labyrinth ring. The rubber seal itself has a simple structure. The advantages of small space and reliable sealing have been widely used, but its disadvantage is that the rubber sealing lip is prone to premature aging under high temperature conditions and loses sealing performance, so the working conditions under high temperature conditions are single. The volleyball slewing ring bearing should adopt labyrinth seal.

Four, working clearance

One of the key factors affecting the operation of the bearing is the working clearance of the bearing. The main factors affecting the working clearance of the bearing include the fit between the inner ring of the shaft and the shaft, the fit between the outer ring of the bearing and the bearing chamber, and the bearing’s own play under non-assembly conditions. Various objective factors such as gaps, equipment operating status and turnover environment. The same mechanical equipment may have different clearances under different operating conditions. To ensure the guarantee effect of the bearing during the operation of the equipment, the selection of the bearing, the determination of the matching relationship, the understanding of the working conditions, the lubrication and maintenance, etc. Comprehensive consideration in many aspects.

The above is the answer to how to ensure the safe operation of the single-row ball slewing ring. Since it is mainly used for large machines, it should be checked and maintained regularly during use to avoid affecting the use of the entire machine.

Positioner Slewing Bearing

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Positioner slewing ring bearings can be used in various industries and play a very important role in our daily life, such as large construction machinery, and small bus accessories that are usually seated.

 

Guidelines for understanding the planning and production requirements of positioner slewing bearings

 

The positioner slewing bearing needs to accept a larger induction load, and its quality requirements are relatively high. Special attention should be paid to the installation to avoid affecting normal operation. The positioner slewing bearing needs to understand certain guidelines when planning and manufacturing. What is required to understand in detail? Here is a detailed introduction for everyone.

 

 

Positioner slewing bearings need to be selected according to operating conditions when planning and manufacturing. For bearings operating at room temperature, chrome bearing steel is required. If the temperature of the principality is higher than 150°C and lower than 250°C, chrome bearing steel is also required. The use of chromium bearing steel requires special heat treatment to avoid affecting normal use.

 

The choice of material for the positioner slewing bearing is particularly important. Because of the need to accept greater impact loads, chromium bearing steel is generally not used. Most of them will choose high-quality carburized structural steel, impact-resistant tool steel, and quenched and tempered structural steel. For corrosive media, corrosion-resistant alloy steel should be selected, which can extend its service life.

 

Because the structure of the bearing parts is relatively complex, the outer ring is equipped with ribs, and it is also required to accept larger impact loads, it is necessary to adopt carburized steel with good processing functions. The outer ring of stamped needle roller bearings can be selected from 08 and 10 low carbon steel. This material steel has better plasticity, so it is more suitable for cold stamping. Swing arrangement and operation arrangement use joint bearings, and use high-performance cold plastic steel.

 

The quality of the positioner slewing bearing depends to a certain extent on the purity of the steel and the uniformity of the arrangement. Following the continuous improvement of the exercise method, a variety of excellent positioner slewing bearings can be produced. For customers in need, please consult online Customer service.

 

How to deal with the positioner slewing bearing if there is a problem

 

Positioner slewing bearing can accept large-scale bearings that summarize the load, and can also accept relatively large axial and radial loads. The slewing bearing is also called a rotating support. It is widely used in industry. It is the relative rotation movement between two objects. Following the continuous development of my country’s slewing ring, it is used in many occupations. How to deal with slewing bearing if there is a problem? The following is a detailed introduction for everyone.

 

If the positioner slewing ring is used for a long time, it will show such problems. This is the limit of accident quality. There are many reasons for such problems. If you do not pay attention to the lubrication, there is foreign matter intrusion. If you do not arrange it in time, it will continue for a long time. It will have a certain impact on the shaft and shell of the positioner slewing support, so special attention should be paid to it during use.

 

If the use of the positioner slewing bearing can not find the cause of the damage, it must be carefully checked during the application process, and the choice of lubricant needs to be selected according to the type, so that it can effectively prevent the surface bearing from showing damage. The slewing ring of the positioner damages the ribs of the roller bearings and simply presents jams, and the lack of lubricant will simply cause problems. If the error of the positioner slewing support device is relatively large, and the shaft deflection is too large, problems will also occur.

 

If there is a problem with the positioner slewing bearing, the cause of the problem must first be found out, and the correct method should be adopted in time to deal with it, so that the use of the bearing can be restored in the shortest time. The service life of other positioner slewing bearings has a certain limit, and it can extend its service life by choosing appropriate methods for maintenance. Therefore, pay attention to the choice of lubricating oil when using it, and avoid foreign matter from entering.

 

Analysis of the cause of abnormal noise in the use of positioner slewing bearing

 

In the daily use of positioner slewing bearings, we may encounter problems of one kind or another. For example, the positioner slewing bearing presents abnormal noise. Many people may think that the positioner slewing bearing itself is defective, but it is different. The reasons for the abnormal noise in the occasion are different. Let’s talk about what the abnormal noise of the positioner slewing ring is.

 

If the newly replaced positioner slewing ring shows abnormal noise during operation, it is a normal phenomenon, which is caused by the lack of lubricating oil. You only need to alter the lubrication on the newly replaced positioner slewing ring. Oil is fine. After the new positioner slewing bearing is installed, it is necessary to apply lubricant to the various parts of the positioner slewing ring first, and check the positioner slewing ring after 100 hours of operation of the positioner slewing ring, see Check whether the pre-tightening force of the above screws and bolts meet the requirements, and then check them after 500 hours of operation. At the same time, avoid the abnormal noise of the positioner slewing ring due to lack of oil in the new positioner slewing ring, so after 50-100 hours, the positioner slewing ring should be made up for a grease.

 

However, if a long-term positioner slewing ring is used, abnormal noise during operation is not a problem of lack of lubricating oil. It may be that a part of the positioner slewing ring is defective or damaged, so stop the positioner slewing Support operations are thoroughly inspected.

 

Therefore, the abnormal noise of different positioner slewing bearings has different reasons. The detailed treatment method should be based on the actual situation. However, no matter what the reason is, the abnormal noise of the positioner slewing ring must be stopped in time. The operation is inspected to avoid delaying the formation of an increase in damage.

What if the slewing bearing rusts?Method to prevent rust of rotary bearing

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Slewing bearings are important parts in many modern machinery and equipment, because their performance is more unique than other mechanical parts, including significant advantages in anti-corrosion performance. However, if the slewing bearing is not produced in strict accordance with the cleaning and anti-rust regulations and the requirements of the oil seal and anti-rust packaging, the bearing parts in the processing process and the finished bearing products after assembly shall be treated with rust; or the anti-rust used in production The quality of rust lubricating oil, cleaning kerosene and other products cannot meet the requirements of the process technology, and the use of inferior anti-rust lubricating oil will cause the bearing to rust. So what can be done to prevent it from rusting? Today, the editor will share with you several ways to prevent the rust of turntable bearings.

1. Surface cleaning method

Cleaning must be based on the nature of the surface of the rust-prevented material and the prevailing conditions, and an appropriate method must be selected. Generally, there are solvent cleaning method, chemical treatment cleaning method and mechanical cleaning method. When the surface is dry and cleaned, it can be dried with filtered dry compressed air, or dried with a dryer at 120~170℃, or dried with clean gauze.

2. Method of applying anti-rust oil

1. Brushing method

This method is suitable for slewing bearings or special-shaped bearings that are not suitable for immersion or spraying. When brushing, it is necessary to pay attention not to produce anti-rust oil accumulation, and of course to prevent leakage.
Slewing ring
2, spray method

Some large slewing bearings cannot be oiled by immersion method, generally use about 0.7Mpa pressure filtered compressed air to spray in clean air. The spray method is suitable for solvent-diluted anti-rust oil or thin-layer anti-rust oil, but complete fire protection and labor protection measures must be adopted. This method is mostly used for rust prevention of some large slewing bearings.

3, soaking method

The slewing bearing is soaked in anti-rust grease, and a thick layer of anti-rust grease can be adhered to its surface. The thickness of the oil film can be achieved by controlling the temperature or viscosity of the anti-rust grease, and this layer of grease can effectively isolate it from The contact of air achieves the effect of rust prevention.

The above are several ways to prevent rusty slewing bearings. I hope everyone can help after reading them. In addition, when we use the bearing, do not directly touch the bearing with your hands, because when sweat contacts the bearing, a layer of sweat film will be formed on the bearing surface. The sweat film will cause electrochemical effects on the bearing and corrode the bearing. Therefore, use special tools such as special gloves or finger cots to pick up the bearing, and do not touch it directly with your hands.

Discussion on the stability of slewing bearings

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For equipment installed with slewing bearings, corresponding performance is the focus of users’ attention, and often requires high accuracy. In the application of equipment, the stability of the slewing bearing can meet the requirements of the special work nature of construction equipment, including bearing large axial load, radial load and overturning moment and other comprehensive loads. The following editor will discuss the stability of the slewing bearing with everyone:

In the design of accessories, the rolling elements are usually separated by separate blocks. This structure can maintain the smoothness of movement, so it is widely used. Special applications require special ball or roller spacers. Bearings installed on horizontal shafts or continuously rotating generators and bearings used in occasions with high requirements for positioning and reliability can use strip combined cages to keep the rolling elements in the correct circumferential position .

The purpose of using cages for slewing bearings is very clear: improve bearing rotation performance and efficiency, consolidate bearing stability and reliability, improve bearing design life and service life, and solve the problems of uniform force and bearing structure under complex working conditions . Integral cage-segment cage-copper cage-steel cage-polyurethane cage-nylon cage-polytetrafluoroethylene cage-PA cage, and composite material cage.

Slewing bearing

In addition, for slewing bearings, stability and reliability are the two core indicators considered in the selection and design of slewing bearings. The main process design considerations are: structure; material; modulation hardness and quenching hardness; bearing rolling elements and The height and wall thickness ratio of the ferrule; machining accuracy; the material, structure and type of the cage, such as the integral cage, can obviously improve the rotation performance and life of the bearing; the lubrication system and the sealing system; the level of installation and debugging; the daily maintenance Frequency; application of mature design.

In order to ensure the stability of construction equipment, the design of slewing bearings pays more attention to the rationality of the structural configuration, but in many cases, gear teeth can be machined on the inner or outer ring of the bearing to simplify the structure of the drive system. In order to avoid problems, when determining the structure of the drive system, you should seek help from related personnel in the gear.

The above is the discussion on the stability of the slewing bearing. The design of pipe fittings pursues higher performance. However, in actual applications, once installation, use or maintenance is improper, various problems may arise, such as in the slewing bearing. There was a problem of excessive shaking during use. Common causes for this are loose mounting bolts, causing shaking during work; insufficient rigidity of the steel structure supporting the slewing bearing, elastic deformation during loading, resulting in overall swaying of the slewing bearing, etc., in order to ensure the normal use of the slewing bearing, if you If there is shaking in the machine, you must stop the machine for inspection in time to prevent long-term shaking from causing greater damage to the slewing bearing.

What should I do if the slewing ring is rusted? Ways to prevent rust of slewing bearings?

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Slewing bearings are important parts in many modern machinery and equipment, because their performance is more unique than other mechanical parts, including significant advantages in anti-corrosion performance. However, if the slewing bearing is not produced in strict accordance with the cleaning and anti-rust regulations and the requirements of the oil seal and anti-rust packaging, the bearing parts in the processing process and the finished bearing products after assembly shall be treated with rust; or the anti-rust used in production. The quality of products such as rust lubricating oil and cleaning kerosene does not meet the requirements of the technical regulations, and the use of inferior anti-rust lubricating oil will cause the bearing to rust. So what can be done to prevent it from rusting? Today, the editor will share with you several ways to prevent the rust of turntable bearings.

　　

　　 1. Surface cleaning method

　　

　　Cleaning must be based on the nature of the surface of the rust-prevented material and the prevailing conditions, and an appropriate method must be selected. Commonly used are solvent cleaning method, chemical treatment cleaning method and mechanical cleaning method. When the surface is dry and clean, it can be dried with filtered dry compressed air, or dried with a dryer at 120~170℃, or dried with clean gauze.

　　

　　 2. Method of applying anti-rust oil

　　

　　 1. Brushing method

　　

　　This method is suitable for slewing bearings or special-shaped bearings that are not suitable for immersion or spraying. When brushing, it is necessary to pay attention not to accumulate rust prevention oil, and of course to prevent leakage.

Slewing ring 

　　2, spray method

　　

　　Some large slewing bearings cannot be oiled by the immersion method, and generally use filtered compressed air with a pressure of about 0.7Mpa to spray in a clean air place. The spray method is suitable for solvent-diluted anti-rust oil or thin-layer anti-rust oil, but complete fire protection and labor protection measures must be adopted. This method is mostly used for rust prevention of some large slewing bearings.

　　

　　3, soaking method

　　

The slewing bearing is soaked in anti-rust grease, and a thick layer of anti-rust grease can be adhered to its surface. The thickness of the oil film can be achieved by controlling the temperature or viscosity of the anti-rust grease, and this layer of grease can effectively isolate it from The contact of air achieves the effect of rust prevention.

　　

　　 The above are a few ways to prevent rusting of slewing bearings. I hope everyone can help after reading them. In addition, when we use the bearing, do not directly touch the bearing with your hands, because when sweat contacts the bearing, a layer of sweat film will be formed on the bearing surface, which will cause electrochemical effects on the bearing and corrode the bearing. Therefore, use special tools such as special gloves or finger cots to pick up the bearing, and do not touch it directly with your hands.