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Import selection and use attentive matters of the bearing


29th June 2013 Bearing Technology 0 Comments

The attentive matters bearing while importing selection and use of the bearing selects the kind, type and size of the summary antifriction bearing to be varied. In order to make the mechanism give play to the anticipated characteristic, it is essential to choose the most suitable bearing. It is a selected bearing, need to analyze a great deal of wants the reason, carry on research, appraise the procedure about choosing the bearing from all angles, there is no special specification, but the general order is as follows:

1 Know the service conditionses of mechanism and bearing,etc.

2 Define the requirements for bearing

3 Type of the selected bearing

4 Selected bearing Direction

5 Selected bearing size

6 Selected bearing specification

7 Selected bearing method of erection

It is to choose the prerequisite of the suitable bearing to hold using the placement, service conditions and environmental condition in the mechanism of bearing correctly in service conditions and environmental condition of the bearing. For it, need to make data and materials of the following several respect:

1 Function and structure of the mechanism

2 Using the placement of the bearing

3 Bearing load Magnitude, direction

4 Rotational speed

5 Shake, assault

6 Bearing temperature Ambient temperature, Wen Sheng

7 Atmosphere corrosivity, cleaning, lubricating property around The choice of the bearing Direction is usually, the axle is being supported radially and axially with two bearings, at this moment, call bearing of one side as and fix the side bearing, it bears two kinds of load of radial and axial, function as relative axial displacement between fixed axis and bearing housing. Call the other side as the free-side, only bear radial load, the axial can relatively move, so as to solve the spacing errors of flexible department question and installation bearing of the axle caused by and temperature variation. As to the fixed side bearing, needing to choose can use the rolling surface in axial movement such as the cylindrical roller bearing Move so as to the mating face ‘ Such as ball bearing entad Bearing. At short axle, fix side and free-side, have under other situations, it uses to be only unidirectional fixed axial movable bearing ‘ Such as angular ball bearing . When the selection of the bearing type chooses bearing type, know the service conditions of the bearing is essential in an all-round way. The table below has listed the master analysis project: Analyze the project Decision-making process

1The intersection of installation and space of bearing can hold on bearing installing the intersection of space and inner bearing type, because pays attention to stiffness and intensity of the axle while designing the line shafting, so generally confirm axle diameter, namely bearing internal diameter first. But the antifriction bearing has many kinds of size series and type, should choose the appropriate bearing type most from it.

2Magnitude, direction and property [the load carrying capacity of the bearing is indicated by basic rated load of the bearing load of load, the bearing load is full of variety that its number value is stated from the size table of the bearing ], whether magnitude, radial load, axial load substantially as loading are unidirectional or two-way, shaking or ballistic intensity,etc.. After considering these factors, and then come to choose the appropriate bearing type most. Generally speaking, the radial load carrying capacity of the bearing of the same internal diameter is increased progressively in following order: Major groove ball bearing < The horn contacts the ball bearing ' Cylindrical a roller bearing ' Taper roller bearing < Roller bearing of cente adjusting

3The rotational speed can adapt to the bearing type [the basic reference of the threshold value of the rotational speed of the bearing is indicated by terminal rotational speed of the mechanical rotational speed, its number value is stated from the size table of the bearing ] the terminal rotational speed of the bearing not only fetches and is but also limited to the bearing size in bearing type, retainer pattern, accuracy class, load condition and lubricating method,etc., so, must consider these factors while choosing. The following bearings are mostly used for the high-speed rotation: The ball bearing of major groove, angle contact the ball bearing, cylindrical roller bearing

4Rotating the precision has the required bearing type [size accuracy and rotation precision of the bearing have been already by GB canonicalization according to bearing type ] basic shaft of the lathe of rotating the precision, fire the turbine and control the machine to expect much and rotate precision, high rotational speed and low friction respectively, at this moment should use 5 the intersection of precision and more than bearings. Generally use the following bearings: Ball bearing of major groove, contacting the ball bearing, cylindrical roller bearing

5Just the characteristic met the bearing type with required and rigid mechanical line shafting [when the bearing bore load, the contact parts of rolling element and ball track will produce elastic deformation. " high stiffness " It is in placements such as basic shaft of the lathe and car last level decelerating device,etc. that the deformation amount which refers to this kind of elastic deformation is minor ], must improve the stiffness of the bearing while improving the stiffness of the axle. It is out of shape younger than the ball bearing that the roller bearing bears load and grows. Exert preloading to bearing ‘ Shoulder the backlash Can improve stiffness. This method is suitable for the angle and contact ball bearing and taper roller bearing.

6Inner circle and relative slope of outer lane analyze, make the intersection of bearing and inner circle and outer lane it produces to be relatively tilted factor ‘ The camber of the axle, precision of the axle and outer cover are bad or installation error as load causes ,Be able to meet the bearing type of this kind of service conditions to and choose. If inner circle and relative slope of the outer lane are too big, the bearing will be caused by the fact that internal load emerges and damaged. So be able to bear such tilted bearing type to should choose. Generally speaking, allow the bank angle or adjust the kernel and angle Increase progressively in following order: Cylindrical the intersection of roller and bearing, the intersection of taper and the intersection of roller and bearing, major groove ball bearing ‘ The angle contacts the ball bearing , cente adjusting roller Ball Bearing

7When detachable frequency count and detachable method to install and dismantle and is checked regularly etc. are detachable and frequent, use the inner circle and detachable cylindrical roller bearing of outer lane, needle bearings and taper roller bearings are comparatively convenient. Round counter bore cente adjusting ball bearing and round counter bore cente adjusting roller bearing can benefit detachably through using the fastener or retreating and unloading one.

The mechanical type of structural selection of the bearing is different, the service conditions of the bearing will differ, not the same to its performance requirement, but generally speaking, the bearing used on an axle is no less than two. Moreover, in order to position axially, mostly use a bearing as the fixed end bearing while using, the others are used as the freedom end bearing. The table below has listed the attachment end and structural choice of end bearing of the freedom. The fixed end bearing of bearing pattern with applicable content is used for making the bearing position and fix and choose the bearing that can bear radial and axial load at the same time to shoulder two-wayly axially in order to bear axially Carry on one’s shoulder or back, also need to consider the corresponding intensity according to the magnitude of axial load at the time of installation.

Ball bearing of major groove Make the angle up and contact the two-bank angle of ball bearing and contact the ball bearing The ball bearing tape of cente adjusting blocks the cylindrical roller bearing NUP type, NH type It is flexible that the free end bearing of roller bearing of cente adjusting of two-bank roller bearing is used for dodging the axle caused by temperature variation at the time of operation, and the axial position used for adjusting the bearing. Should choose and only bear the radial load, inner circle and very separable bearing of outer lane. When use is not a split bearing, the outer lane, with generally adopting and clearance fitting between the outer covers, so that dodge axially together with bearing when the axle is flexible. The ones that are used for dodging the axle caused by temperature variation at the time of operation are flexible, and the axial position used for adjusting the bearing. Should choose and only bear the radial load, inner circle and very separable bearing of outer lane. When use is not a split bearing, the outer lane, with generally adopting and clearance fitting between the outer covers, so that dodge axially together with bearing when the axle is flexible. Divide attachment end and at the free end when quite the intersection of bearing and the intersection of interval and little, the intersection of axle and flexible influence, two angles that can bear axial load are exposed to front or the back such as the ball bearing or taper roller bearing to dispose and use. Adjust the axial backlash after installing with the nut or shim. Ball bearing of major groove The angle contacts the ball bearing cente adjusting ball bearing Cylindrical roller bearing NJ type, NF type The attachment end can bear radial load and bearing of the axial load to choose at the same time when the taper roller bearing cente adjusting roller bearing is used in the vertical shaft. When bearing of axial load axial load large, and the bearing is used simultaneously entad thrust bearing. The same free end chooses the bearing only bearing radial load, flexible for what has been dodged the axle. Attachment end make corner up keep in touch the ball bearing ‘ The back is made up Two-bank a taper roller bearing ‘ 37000 type And thrust bearing and bearing entad use, it installs the bearing to be delicate machine components, please don’t open packaging before installation, avoid getting rusty. To already bearing and double-sided to have oil seal or dust cap, bearing of the seal ring but direct mount that lipoprotein lubricate, needn’t wash. *In the installation of the method bearing, must know a principle, namely can only transmit and install the strength or force moment by corresponding collar. Press fit the intersection of bearing and inner circle and axle enable fit tightly, outer lanes and bearing seat holes are relatively at the time of loose fit, the available pressure machine presses the bearing first and is mounted on the axle, then put the axle into seat hole of the bearing together with bearing, pad the assembly clutch copper or soft steel that a soft metallic material is done on the inner circle end of the bearing at the time of pressure mounting . Bearing outer lane and bearing seat hole are fitted tightly, inner circles and axles are relatively at the time of loose fit, can press the bearing in the seat hole of the bearing first, the external diameter of the related tube of this fashion should be slightly smaller than the diameter of the seat hole. When bearing ring, axle and seat hole are fitted tightly, installing the indoor cycle sum outer lane will be pressed in axle and seat hole at the same time, should be able to escort the end of outer lane of the cycle sum in the urgent bearing at the same time in structure of the assembly clutch. Heat and cooperate it through heating the bearing or pedestal, utilize thermal expansion to change the close fit into the loose fit method of erection. It is a daily method of erection saving effort. This method suitable for the intersection of increscence amount and old installation of bearing, may the intersection of separate type and collar of bearing put into fuel tank and heat 80-100 ℃ evenly bearing before heat install, then take out from the oil and put into the axle as soon as possible, in order to prevent the end of inner circle is not laminated with the shaft shoulder closely after cooling, the bearing can be fastened axially after cooling. When bearing outer lane and light and metallic pedestal are fitted tightly, adopting heat which heats the pedestal holds the method, can prevent the fitting surface from being abraded. While heating the bearing with fuel tank, there should be a reticular grid from certain distance place of bottom of the case, hanging the bearing with the hook, the bearing can’t be put to the bottom of the case, so as not to sink impurity entering bearing or not homogeneous heating, there must be thermometers in the fuel tank, the oil of rigid control is warm can’t exceed 100 ℃, in order to prevent the back fire effect, make the hardness of the collar reduce. The thorough and cooperation of the axle of the installation thrust bearing of the thrust bearing is generally transition fit, base ring and cooperation of the seat hole of the bearing, generally in order to clearance fit, so this kind of bearing is apter to install, the mean axis spring of the two-way thrust bearing should be in the upper setting of the axle, in order to prevent to axial rotation. The bearing method of erection, generally speaking it is that a revolutionary situation of an axle is in the majority, so inner circle and cooperation of the axle, in order to cross beating cooperating, the bearing outer lane and the cooperation of the bearing room, in order to clearance fit. *The bearing needs to check after operating the bearing installation of inspection well, should guarantee the bearing is installed in place, it is flexible to rotate, without stagnat phenomenon of card, for instance, the bearing is installed improperly, will make the bearing temperature rise and damage rapidly, the bearing even happens to seize the major accident of rupturing etc.. Use and custody of the bearing 1 When the bearing uses, keep the cleaning of the ambient enviroment, don’t glue and is grasped sweat and dirt. Stipulate that is used by the personnel familiar with the bearing, especially take care the wounded, impression, owing decreasing etc.. In order to guarantee the usability of the bearing, in conformity with the operation or work standard of Ju’s apparatus of the root, maintain, maintain and overhaul the bearing regularly, the content includes controlling the running status, supplementing lubricant, dismantling the inspection regularly. 2 The bearing can’t be stored on the ground directly ‘ Need to fly off the ground above 30cm ,Avoid penetrating light and sombre wall directly. In order to prevent getting rusty, keep in the environment of the temperature about, under 65% of humidity 20 ℃, bearing put in acid air, easy to get rusty, change color, want, answer the silk polish bearing, axle, outer cover with glove, kapok, the rubbish enters the bearing and cooperates partly the out of order reason happen, so need to pay attention to. Stainless steel covered electrode










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