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Method of dynamic balance of machine tool spindle

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  The application and development of high-speed machine tools require the increase of spindle speed. However, in the manufacturing process of machine tool spindle group parts, it is inevitable that the center of gravity will deviate from the center of rotation due to uneven material, asymmetric shape and machining and assembly errors, which will cause vibration and vibration force of the machine tool, noise of the machine tool and heating of the bearing. With the increase of rotating speed, the vibration caused by imbalance becomes more and more intense. Because the deformation of the spindle assembly of machine tool is very small when it rotates, in order to simplify the calculation, it is regarded as a balancing method of rigid rotor. The rotor is regarded as an absolute rigid body, and it is assumed that the rotating shaft will not be significantly deformed under the action of unbalanced centrifugal force when working. Therefore, under these conditions, many complex unbalanced s...
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New process of rust prevention between processes for precision imported bearings

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  Rust occurred, which not only affected the accuracy and surface roughness, but also reduced the service life, even scrapped and could not be used. Bearing rust prevention is an important work, especially the rust prevention between processes. For example, there are many processes for bearing after pickling, cleaning and grinding in heat treatment workshop. When the product is not produced by assembly line, it will be stored in the intermediate warehouse after one-time sequential processing, so the bearing rings stored between processes must be rustproof. Traditional rust-proof methods using the same rust-proof oil as rust-proof paint and their shortcomings generally adopt the following methods for rust prevention between bearing processes: 1. Immerse in the rust-proof tank Immersing the bearing ring in the aqueous solution of 5% sodium nitrite and 0.6% sodium carbonate has a good antirust effect, but it takes up a lot of space and is inconvenient to manage. 2. Dip coating concent...
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Installation of bearing housing

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  1. Standard type Several methods of installing bearing box with snap ring and fixing plate. Installing bearings with set screws will cause deformation of bearing housings and should be avoided as far as possible. 2. Flange type When installing flange type linear bearing, the matching bearing box bore surface accuracy must be accurate. 3. Adjustable integer (small opening type) When the opening on the bearing is perpendicular to the opening on the bearing box, a uniform preload in the circumferential direction can be obtained. 4. Large opening type If it is used with a suitable bearing seat, the clearance of the large opening bearing can also be adjusted, and even the preload can be lightened. 5. Precautions during installation When installing the linear bearing into the bearing seat, auxiliary work should be used to avoid directly knocking on the end face or sealing ring. The bearing should be used to guide it evenly, and the buffer plate should be used to install it with the hel...
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Repair conditions and best methods of rolling bearing

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  Rolling bearings are mass-produced mechanical parts, and the manufacturing accuracy is very strict, and the degree of technical specialization is very high. Therefore, for the vast majority of bearing varieties that are easy to buy, it should be more cost-effective to buy than repair. Only under the following circumstances can the bearing repair be considered, namely: (1) The failure forms of a large number of bearings of the same model used in large factories are mainly the wear, fatigue or fretting of rolling surfaces, especially the damaged parts are mostly cages or rolling bodies, and the rings or washers still have repair value; (2) Large and extra-large bearings are on the verge of failure, or have failed without major damage to parts, or expensive bearings must try to extend their effective service life; (3) Some bearing varieties that are really difficult to buy have to be repaired without spare parts after failure, especially imported bearings; (4) The bearing is slightl...
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Stop inspection of rolling bearing

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  It is very important to check the bearing seal regularly to keep the bearing in the best condition. The most favorable inspection time is arranged in the periodic downtime inspection period. Importance of clean bearings: It is important to keep bearings and lubrication clean. Before inspection, clean the machine surface, and then remove the parts around the bearing. The oil seal is a very fragile part, so it needs to be disassembled carefully. Do not apply excessive force, and then carefully check the oil seal and its surrounding parts. If it shows bad symptoms, it must be replaced. Bad oil seal will lead to bearing damage and equipment shutdown. Check lubricant Rub a little lubricant between your fingers. If there are pollutants, you can feel them, or apply a thin layer of lubricant on the back of your hand, and then seal the light for inspection. Change lubricant After draining the old oil from the oil-lubricated bearing, if possible, fill it with fresh oil and let the machine ...
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Selection of bearing size

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  Determining bearing size parameters On many occasions, the inner hole size of bearings has been specifically defined by the structure of machines or devices. No matter whether the working life, static load safety factor and economy meet the requirements, the remaining dimensions and structural forms of bearings must be calculated before they are finally selected. This calculation includes comparing the actual load of the bearing with its load capacity. Static load of rolling bearing means that the bearing is static after loading (there is no relative motion between inner and outer rings) or the rotation speed is very low. In this case, the safety factor of excessive plastic deformation of raceway and roller is calculated. Most bearings are subjected to dynamic load, and the inner and outer rings move relatively. The safety factor of early fatigue damage of raceway and rolling elements is checked by dimensional calculus. Only under special circumstances, the nominal life calculati...
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Failure form of rolling bearing

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  Failure form of rolling bearing Abnormal heating, vibration and sudden increase of noise occur in the running process of the rolling imported bearing, which indicates that the rolling imported bearing may have been damaged, and the reasons should be checked and analyzed in time. Common failure forms are: 1. Fatigue spalling On the raceway or roller surface of the rolling inlet bearing, the surface metal of the contact surface exfoliates and gradually expands to form pits due to the alternating load. If the operation continues, an area peeling area will be formed. Due to improper installation or the inclination of the bearing seat hole and the center line of the shaft, the local area of the bearing will bear a large load and early fatigue failure will occur. 2. Cracks and fractures Material defects, improper heat treatment, excessive fit interference and improper combination design, such as stress concentration caused by grooves on the bearing surface, will form cracks and fractur...
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