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Bearings, as a kind of mechanical conventional parts, are unavoidable with the use of equipment, so when our equipment or machines are routinely repaired or damaged, we need to disassemble the bearings, especially when the bearings are disassembled for faults, check the parts around the bearings, lubricate them. The situation of the agent and the bearing itself can be more clearly known to the fault, then the following editor of Hengguan Bearing will introduce the disassembly method of the slewing bearing to you.
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1. Instructions before disassembling the slewing bearing
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1. Use of dismantling tools
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(1) Use manual or hydraulic
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(2) Only use a special wrench
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(3) Use a puller
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(4) Use induction heating equipment (inner ring)
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(5) Use oil injection method
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2. How to disassemble
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(1) It should be carried out by or under the guidance of experienced personnel;
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(2) Before starting the disassembly, determine the specific method to be disassembled;
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(3) Keep the necessary bearing removal tools handy;
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(4) When reusing or inspecting a disassembled bearing, be careful to avoid scratching or damaging the bearing raceway or rolling elements; when disassembling the bearing from the bearing seat, the disassembly force is applied to the outer ring; when disassembling the bearing from the shaft, the disassembly force is applied to the outer ring. inner circle;
Slewing bearing
Second, the disassembly method of the slewing bearing
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1. Cold disassembly
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When removing smaller bearings, the bearing ring can be removed from the shaft by lightly tapping the side of the bearing ring with a suitable punch, preferably with a mechanical puller. The pull should act on the inner ring or adjacent components. Removal can be simplified if the shaft shoulder and housing shoulder have grooves to accommodate the puller grip. In addition, some threaded holes are machined at the position of the hole shoulder to facilitate the bolt to push the bearing out.
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Large and medium-sized bearings often require more force than machine tools can provide. Therefore, the use of hydraulic power tools or oil injection, or both, is recommended. This means that oil holes and oil grooves need to be designed on the shaft.
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2. Hot disassembly
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When disassembling the inner ring of needle roller bearings or NU, NJ, and NUP cylindrical roller bearings, the hot disassembly method is suitable. Two commonly used heating tools: heating rings and adjustable induction heaters.
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The heating ring is usually used to install and remove the inner ring of small and medium-sized bearings of the same size. The heating ring is made of light alloy. Heating rings are radially slotted and equipped with electrically insulating handles.
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If the inner rings of different diameters are frequently disassembled, it is recommended to use a debuggable induction heater. These heaters quickly heat the inner ring without heating the shaft. When disassembling the inner ring of a large cylindrical roller bearing, some special stationary induction heaters can be used.
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3. Remove the bearing installed on the conical shaft diameter
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The small bearing can be removed by pulling the inner ring with a mechanical or hydraulic puller. Some pullers are equipped with spring-operated arms, and the use of this self-aligning design of the puller simplifies the procedure and avoids damage to the journal. If the puller claws cannot be used on the inner ring, the bearing should be disassembled through the outer ring or by using a puller combined with a puller.
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When using the oil injection method, the disassembly of medium and large bearings will be safer and easier. This method injects hydraulic oil between two conical mating surfaces under high pressure through oil holes and oil grooves. The friction between the two surfaces is drastically reduced and an axial force is created that separates the bearing and shaft diameter.
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4. Remove the bearing on the adapter sleeve
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For the small bearing installed on the adapter sleeve with the straight shaft, you can use a hammer to knock the small steel block that acts evenly on the end face of the inner ring of the bearing to remove it. Before doing this, the adapter sleeve lock nut needs to be loosened a few turns. For small bearings mounted on the stepped shaft of the adapter sleeve, it can be removed by hitting the small end face of the adapter sleeve lock nut with a hammer through a special sleeve. Before doing this, the adapter sleeve lock nut needs to be loosened a few turns. For bearings mounted on a stepped shaft with an adapter sleeve, the use of a hydraulic nut makes bearing removal easier. To do this, a suitable stop must be installed close to the hydraulic nut piston. Oil injection is the easier method, but an adapter sleeve with oil holes and oil grooves must be used.
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5. Remove the bearing on the withdrawal sleeve
When removing the bearing on the withdrawal sleeve, the locking device must be removed. (such as lock nuts, end plates, etc.) For small and medium-sized bearings, lock nuts, hook wrenches or impact wrenches can be used for disassembly.
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For medium and large bearings installed on the withdrawal sleeve, the hydraulic nut can be used to easily disassemble. It is recommended to install a stop behind the hydraulic nut on the shaft end. The stop device can prevent the withdrawal sleeve and the hydraulic nut from flying out of the shaft when the withdrawal sleeve is suddenly separated from the mating position.
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The above is the relevant content about the disassembly method of the slewing bearing. I hope it will be helpful to you. In addition, we have rich experience in the production of slewing bearings and slewing bearings. If you need it, please feel free to inquire

Recently, the high-end slewing bearing for medical CT machine designed and produced by our company for customers has been successfully rolled off the production line, and all the indicators of the finished product have passed the inspection.

For the CT machine special slewing bearing, we understand the various technical requirements of the customer, and calculate the bearing capacity and service life according to this requirement. After more than a month of full technical communication, Technical parameters, confirmed the production drawings. This product has an outer diameter of 1180mm and an inner diameter of 980mm. It has a toothless four-point contact ball slewing bearing structure with P5 accuracy. It is a high-end precision slewing bearing; and because it is medical, it has extremely high requirements for noise reduction.

According to the actual working conditions of customers, our technical engineers actively improve the product processing technology, and strive to make products that meet the actual needs of customers. First, the 42CrMo quenched and tempered material is used to make the material performance better and more stable, which guarantees the product quality from the source; secondly, the product raceway and appearance are comprehensively polished to ensure high product precision; thirdly, for the product’s silent requirements, A special segmented nylon cage device is used to lock the ball in the cage pocket while ensuring that the steel ball can rotate freely, thereby reducing the noise impact caused by the free movement of the cage in the raceway. Reduce rotating noise. Through the above efforts, we ensure that the finished products of the slewing ring meet various technical requirements.

After the finished product came out, after trial assembly test, it has fully met the requirements of the confirmed drawings of both the customer and us, and the rotation is flexible and light, and the rotation is silent. At present, this product is already on the way to customers.

The vision of “Let the world fall in love with Made in China” is not only a slogan, but also implemented in practical actions. It requires countless Chinese companies to constantly challenge themselves technologically and seize the right to speak for China in the core field of manufacturing. In the era of high-tech industry, only Chinese manufacturing can win the “tough battle” and truly realize “Let the world fall in love with Chinese manufacturing!” We Hengguan people carry this great dream and actively practice it! The road is long and long, Hengguan people will persevere in pursuit! May you and I walk along this great journey…

The heat treatment operation of continuously cooling the quenched workpiece from normal temperature to a lower temperature to transform the retained austenite into martensite is called cold treatment. The purpose of cold treatment is to improve the hardness and wear resistance of steel, and stabilize the size of the workpiece. It is mainly used for bearings, tools and some carburized parts.

1. Cold treatment process of bearing steel

The cold treatment of bearing steel often uses a freezer and dry ice alcohol solution. Precision bearings have higher requirements for dimensional stability; after the ring is quenched (especially staged quenching), the internal structure still retains more retained austenite. This retained austenite is an unstable structure. When storing and using the bearing In the process, changes will continue to change the accuracy of the bearing. For this reason, the cold treatment process is adopted, which can reduce the retained austenite in the structure and slightly increase the hardness of the parts.

After quenching and cooling the workpiece to room temperature, it is immediately placed in an environment below room temperature for a certain period of time, and then taken out and placed at room temperature. This treatment below room temperature is called cold treatment. The cold treatment of bearing steel often uses a freezer and dry ice alcohol solution. Stay at room temperature after quenching: After quenching, the material must be cooled uniformly inside and outside to room temperature and then cold treated, otherwise it will be easy to crack. Cold treatment immediately after cooling to room temperature (generally no more than 30min), otherwise it will stop the transformation of austenite to martensite change.

2, cold treatment temperature

The temperature of the cold treatment is mainly based on the martensitic transformation termination temperature Mf of the steel. In addition, the influence of the cold treatment on the mechanical properties and the manufacturability should also be considered. For GCr15 steel, the cold treatment is -70℃; when the precision requirements of ferrules or equipment are limited, the cold treatment temperature can be -40～-70℃; for ultra-precision bearings, it can be between -70℃～-80℃ Perform cold treatment in between. The temperature of the subcooling affects the impact fatigue and contact life of the bearing.

3, cold treatment heat preservation

Although the transformation of a large amount of martensite is completed when it is cooled to a certain temperature, in order to make the surface and core of a batch of ferrules reach the cold treatment temperature uniformly, a certain holding time is required, generally 1～1.5h.

4. Tempering after cold treatment

The ferrule is placed in the air after cold treatment, and its temperature is slowly raised to room temperature and then tempered in time. The temperature rise should not be too fast, otherwise it is easy to crack; the tempering is timely, otherwise the larger residual stress inside the ferrule will cause the ferrule to crack, generally not more than 2h.

5. cold treatment time

For the length of holding time of cold treatment, some scholars believe that the amount of retained austenite transformed into martensite depends only on the temperature reached by cooling, and the retention time at low temperature does not matter, because retained austenite-martensite transforms at low temperature The cooling is completed in an instant, so there is no need to keep it at a low temperature, just let the workpiece cool from the outside to the inside. It is also believed that the cold treatment time should be determined according to the thermal conductivity of the workpiece, the volume, the time required for cooling through, and the stability of the transformation of retained austenite. The retained austenite in the steel is fully transformed and is more conducive to the formation of carbide particles. After the transformation is completed, the hardness of the parts will not change significantly. Therefore, the holding time of cold treatment also needs to be reasonably controlled according to the actual situation.

In fact, there are many studies on cold treatment of bearing steel, including GCr15 steel, aviation high temperature bearing steel, carburized bearing steel, etc., except for the reduction in toughness (decreased impact toughness, 21% reduction), almost all of the research All show the many advantages of cold treatment: reduced Paralympics; increased hardness; increased wear resistance; increased tensile strength; fine carbide precipitation, increased fatigue life, etc.

Bearings are key machine parts that bear load and transmit motion. The challenges brought about by the increasing power density of modern equipment manufacturing industry have put forward higher requirements on the bearing capacity and reliability of bearings. Today, the editor will come to talk with you about methods and measures to improve bearing fatigue life.

Bearings in specific applications will fail prematurely, and their service life only accounts for 5%-10% of the calculated rated life. Many early failure bearings have a typical feature-a large-area subsurface crack network with “white etching morphology”, that is, white etching cracks.

There are many factors affecting white etching cracks, including raw materials, bearing design, lubrication, stress, surface and many other aspects. Among them, the bearing steel as a raw material, its composition design, purity, carbides, internal pores and other improper control will cause white corrosion cracks and cause early failure of the bearing. In order to obtain a high and stable fatigue life, the following aspects of the bearing steel production process must be done:

Slewing bearing

1. According to the application environment and characteristics of the bearing, select and design suitable bearing steel varieties, establish chemical composition internal control standards, and focus on the control of residual and harmful element content.

2. The oxygen content of the bearing steel, non-metallic inclusions and other purity indicators are improved through measures such as the control of the oxygen content of the steel in the primary furnace, the control of the amount of slag, the control of the slag composition, the control of the refining and pouring process, and so on.

3. According to different carbide quality requirements, choose different smelting processes such as vacuum degassing, electroslag, and self-consumption to obtain the corresponding level of carbide level. At the same time, we will do a good job in the process of temperature injection speed control, high temperature diffusion and other aspects of process optimization, to further improve the size and distribution of carbide particles, and reduce the risk of bearing fatigue life reduction caused by residual stress caused by microstructure changes.

4. For the rolling elements, the control of the microscopic pores in the bearing steel is even more important because there is no longer any thermal deformation treatment in the bearing manufacturing process. In the production process, it is necessary to focus on the control of processing methods, processing ratios, heating systems, etc.

5. Establish a complete bearing steel inspection system. On the one hand, it is necessary to formulate detailed laboratory sample preparation inspection plans, make full use of laboratory testing capabilities, objectively evaluate the physical quality level of each heat, and do a good job of high-frequency water immersion The promotion and application of new methods such as flaw detection and maximum extreme value detection; on the other hand, make full use of on-site surface and internal automatic flaw detection equipment to prevent the outflow of defective steel. Through the implementation of the above measures, the product quality level and quality stability are improved, thereby reducing the bearing white corrosion crack defects caused by raw materials.

Bearing manufacturing is a systematic engineering, and every link and step is very important. Therefore, in the design and production of bearing steel components, bearing manufacturing, heat treatment, processing and assembly, etc., qualified bearing products must be produced in strict accordance with the requirements of the standard.

In recent years, industrial robots have ushered in explosive development, especially due to the increase in labor costs, making manufacturing companies increasingly favor the use of more mechanized, more efficient, and lower-cost robots. When it comes to robots, we have to mention one of the important components, the reducer, which is what we often call the reducer. Due to the different operating environments and performance of industrial robots, the types of reducers used are also different. So, do you know why an industrial robot needs a reducer?

The power source of an industrial robot is generally an AC servo motor. Because it is driven by a pulse signal, the servo motor itself can realize speed regulation.

Industrial robots usually perform repeated actions to complete the same process; in order to ensure that industrial robots can reliably complete process tasks in production and ensure process quality, the positioning accuracy and repeat positioning accuracy of industrial robots are very high. Therefore, to improve and ensure the accuracy of industrial robots, rv reducers or harmonic reducers are needed. Another role of precision geared motors in industrial robots is to transmit greater torque. When the load is large, it is not cost-effective to blindly increase the power of the servo motor. The output torque can be increased by a reducer within a suitable speed range.

In addition, the servo motor is prone to heat generation and low-frequency vibration under low-frequency operation, which is not conducive to ensuring accurate and reliable operation of industrial robots that work for a long time and periodically. The existence of the precision geared motor enables the servo motor to run at an appropriate speed, and accurately reduces the speed to the speed required by each part of the industrial robot, which improves the rigidity of the mechanical body while outputting greater torque. Compared with general-purpose reducers, robot joint gear motors are required to have the characteristics of short transmission chain, small size, high power, light weight and easy control. There are two main types of reducers widely used in articulated robots: rv reducers and harmonic reducers.

Industrial robots usually perform repeated actions to complete the same process; in order to ensure that industrial robots can reliably complete process tasks in production and ensure process quality, the positioning accuracy and repeat positioning accuracy of industrial robots are very high. Therefore, to improve and ensure the accuracy of industrial robots, RV reducers or harmonic reducers are needed. Another role of precision reducers in industrial robots is to transmit greater torque. When the load is large, it is not cost-effective to blindly increase the power of the servo motor. The output torque can be increased by a reducer within a suitable speed range. In addition, the servo motor is prone to heat generation and low-frequency vibration under low-frequency operation, which is not conducive to ensuring accurate and reliable operation of industrial robots that work for a long time and periodically.

The reducers commonly used in industrial robots include RV reducers and harmonic reducers. Harmonic reducers are mainly used for light-loaded parts such as forearms, wrists, and hands. The RV reducer has a large transmission ratio range, relatively stable accuracy, high fatigue strength, and higher rigidity and torque carrying capacity.

In recent years, as the market for industrial and life assistance robots continues to expand, the demand for high-precision small modulus gears in precision reducers used in the joints of robots has also increased sharply. The robot-specific slewing ring (slewing bearing) products produced by Luoyang Hengguan have the advantages of light weight, high precision, reasonable price, and excellent service; our company has a professional production line for such products, which specializes in the production of such high-precision slewing bearings. It is also one of the main product series of our company. You are welcome to call for consultation and look forward to cooperating with you.