Large deformation of bearing characteristics, processing technology and the introduction of repair

Bearing shell can also be referred to as the sliding bearing, the work is mainly with the shaft collar forming oil film clearance, a very thin layer of oil film lubrication when the relative motion. If poor lubrication, may result in direct contact with the shaft and bearing, friction, the friction produced by high temperature will result in bearing damage. Although bearing shell is made of high temperature resistance of the copper alloy materials, but direct contact friction produced by high temperature can still be damaged, so the clearance between the shaft and bearing determines the accuracy of the sliding bearing, the shaft and bearing shell processing is the key to ensure accuracy of bearing. 1, large diameter and thin wall bearing characteristic of large diameter thin-walled bearing generally refers to the aperture of 560 mm, the thickness of 25 mm or less or more radial stiffness very small set of classes, the main technical indicators: cylindrical, the inner hole size tolerance; Cylindrical, inner hole of the roundness error; Inside and outside the circle of alignment error; The perpendicularity errors of end face and inner hole, as shown in figure 1. As a result of the limitation of this type of bearing structure. The most common problem is in the process of producing by cutting heat, cutting force and clamping deformation caused by the influence of bearing bush of the machining accuracy can not meet the drawing requirements, the general technological process is coarse - car Shard - Milling faying surface - Combination - Half a fine car, car, while the processing technological process basic are all the same, but the specific processing parameters and methods such as improper selection, processing quality might be totally different. While storing deformation is more than some man-made factors. 3, the optimization of machining process 3. 1 choose reasonable tool and cutting parameter 1) The choice of the cutting tool. 0%, with high mechanical properties. Good abrasion resistance and corrosion resistance, tensile strength CRB acuity 490 mpa, yield strength s acuity l80MPa, elongation is 13% or higher, is a kind of free-cutting alloy, can choose ordinary HSS or cemented carbide cutting tool materials. Can use the larger rake Angle and the Angle, the cutting tool choice of each Angle as shown in figure 2. 2) Selection of cutting parameter. In order to reduce vibration and deformation of workpiece, should make the workpiece on the cutting force and cutting heat as small as possible, therefore should choose when machining high cutting speed, small cutting depth and feed. 3. 2 clamping force impact on the deformation of the 1) The installation of artifacts. Using horizontal lathe processing, need to leave a chuck and stress release slot (car See figure 3) , using axial workpiece clamping, done in a clamping, at one end and the cylindrical surface processing, minimize the clamping effect on the radial deformation. 2) Such as radial clamping workpiece must be used, in order to reduce clamping deformation, should increase the number of jaw, increase the contact area. Also can add auxiliary support when necessary. 3. 3 the control of cutting heat cutting process of cutting heat is inevitable, the heat is not only influence the deformation of the workpiece cutting tool durability will produce very big effect. Therefore in the process of processing must use plenty of cutting fluid, coarse car can choose small emulsion concentration, using larger emulsion concentration when finishing. 4, bearing shell deformation repair because of the influence of the bearing shell process by cutting stress and restricted by equipment in the process of operation, placed, deformation is inevitable. Through years of practice, found that most of the deformation are tile diameter in the subdivision surface decrease. After installed on the bearing seat, tile edging in reducing state, which lead to bearing outside diameter and hole bearing contact area can not meet the requirements. In view of the above appear deformation, the actual production process, generally adopts hydraulic press with wooden tooling repair ( See figure 4) 。 First install the bearing to the shaft, the bearing shell top surface of the wood, and according to the deformation textures and the size of the gasket thickness. Gradually loading the pressure of the hydraulic press, fall down after unloading workpieces, check the tile edging diameter size, according to the measured results whether really need school form again.