Assembly of plain bearings

(1) Main technical requirements The main technical requirements for the assembly of sliding bearings are: the matching surface of the journal and the bearing reaches the specified number of contact points per unit area; the matching clearance meets the specified requirements to ensure good lubrication during operation; the lubricating oil pipeline is unobstructed and the holes The mouth is in the correct position. Ordinary radial plain bearings have three structural forms: integral, split and tapered surfaces. The integral structure is simple, the bushing and the bearing seat are connected by an interference fit, and the inner hole of the bushing is divided into two forms: a smooth cylindrical hole and a cylindrical hole with oil groove, as shown in Figure 12-16. The gap between the shaft sleeve and the journal cannot be adjusted, and it is very inconvenient to move the shaft or bearing in the axial direction when the mechanism is installed and disassembled. For the split bearing, the gap between the bearing bush and the journal can be adjusted, the installation is simple, and the maintenance is convenient. The shaft sleeve of the tapered surface bearing has two structures of outer column inner cone and outer cone inner column. The gap between the shaft sleeve and the journal is adjusted by the axial relative position of the shaft and the shaft sleeve. Fig. 1 Bushing of integral sliding bearing (2) Key points of assembly operation of integral bearing ①Press the bushing. Before press fitting, clean and lubricate mating surfaces. The bushing with oil hole should be aligned with the circumferential position of the oil hole on the bearing seat before pressing, and the bushing without shoulder should be flush with the end face of the seat hole after being pressed into the bearing seat. Press-fit shaft sleeves can be knocked in with a hammer or pressed in with a punching machine, but care should be taken to prevent the shaft sleeves from skewing. There are three commonly used press-fitting methods, as shown in Figure 2. 1-Liner 2-Sleeve 3-Guide sleeve 4-Special mandrel Figure 2 Press-fit method of the bushing> Press-in with a spacer: Put a spacer 1 on the sleeve 2, and tap it directly with a hammer bearing housing. The function of the gasket is mainly to avoid damage to the bushing. This method is simple, but it is prone to the skew of the bushing. > Press-in using guide sleeve: Use the guide sleeve 3 while using the gasket, and the direction of pressing is controlled by the guide sleeve to prevent the shaft sleeve from skewing. >Use special mandrel: Use special mandrel to guide, mainly used for press-fitting of thin-walled bushings. ②The correction of the bushing hole wall. After the bushing is pressed in, the inner hole is easily deformed, such as the size becomes smaller, the roundness and cylindricity errors increase, etc. In addition, the coaxiality error of the bushing holes of the bearings at both ends of the box (body) will also increase. . Therefore, the matching between the bearing and the shaft should be checked, and corrections should be made according to the specified clearance between the shaft sleeve and the journal and the number of contact points per unit area until the specified requirements are met. Axle sleeve hole wall correction