Correct installation of NACHI machine tool spindle bearings determines bearing life, accuracy and performance. The steps to install the main shaft bearing are as follows: a First, check the shaft and bearing seat b Unpack and clean c Installation d Confirmation after installation 9.2.1 Inspection of the shaft bearing seat ● Thoroughly clean the shaft and bearing seat to remove dust or debris. Also check for cracks and burrs. ● Check and record whether the dimensions of the shaft and the bearing housing, the verticality and fillet of the shaft shoulder meet the requirements of the drawing. As shown in Figure 9.1, measure 2 positions in the axial direction and 4 positions in the circumferential direction. ● Figure 9.1 The measuring position of the inner diameter of the shaft diameter bearing seat 9.2.2 Unpacking and cleaning ● Please do not open the package before using the bearing. Wear latex gloves when unpacking. Opening the bearing package without latex gloves can allow dust to enter the bearing or cause rust. ● The surface of the unpacked bearing is coated with anti-rust oil. Please use kerosene or clean gasoline for cleaning. When cleaning, use a spray with filter or use a rough washing tank and a fine washing tank with a metal mesh at the bottom of the tank. ● Cover the cleaned bearing with a dust cover after degreasing. Do not rotate the degreased bearing. Bearing use 9-1 Bearing storage and transportation. NACHI spindle bearings are precision components. Therefore, handle with care to prevent damage caused by vibration. Care should also be taken to prevent dirt or rust during storage and handling. ● Bearings should be stored in a cool, dry place away from direct sunlight. ● Do not place the bearing directly on the ground. Bearings should be stored on a shelf 30cm above the ground to prevent dust accumulation. ● Inventory management should be first-in, first-out. When shipping, start shipping from the product with the earlier packing date. ● Bearings should be handled with care to collapse or fall. Avoid bearing damage due to impact. Deformation, or damage to the packaging causes dust to enter. Generally, the bearing installed on the machine tool has an interference fit on the shaft and a clearance fit on the bearing seat. There are thermal expansion method and press fit method for mounting the bearing on the shaft. The thermal expansion method is a method of heating and expanding the bearing above the interference between the shaft and the inner ring. The use of an induction heater with degaussing device (Fig. 9.2) or heating from a heating bath can avoid undue stress on the inner ring and shorten the operating time. The heating temperature should not exceed 120 degrees. Otherwise, the hardness of the bearing steel will be reduced and the life of the bearing will be shortened. Install the heated bearing on the shaft, and the axial direction will shrink after cooling, and there will be a gap between the inner ring and the shaft shoulder (Fig. 9.3), and lock it with a nut. [Press-fit method] A method of pressing the end face of the inner ring with a jig and pressing the shaft with a press or a jack (Fig. 9.4). Do not apply force to the outer ring or cage when the inner ring is pressed in. Especially when installing angular contact ball bearings, applying force in the opposite direction of the contact angle will cause damage to the shoulder of the track and the ball, so be sure to avoid it (Fig. 9.5). ● Fig. 9.4 Press-fit ball of the inner ring may be damaged ● Fig. 9.5 Mounting direction of NACHI angular contact ball bearing Reference: The maximum radial runout position is marked with u0026#1048675; on the end faces of the outer ring and inner ring at the maximum radial runout position. Shaft runout can be minimized by aligning the shaft radial runout minimum position with the inner ring u0026#1048675; marked position. The same is true for the outer ring, the minimum position of the bearing seat runout must be aligned with the marked position of the outer ring u0026#1048675; In addition, the position of the V mark on the outer ring is independent of the position of the assembly indication < on the outer diameter surface. Maximum Radial Runout Picture Figure 9.6 Maximum Radial Runout Position Reference: Mounting and Dismounting Force The force required to press the bearing inner ring into the shaft (solid center) or dismount varies due to interference or the degree of machining of the shaft, but can be determined by the formula 9.1 Roughly calculated. (Formula 9.1)Ka : Press fit force or dismounting force (KN)fk : Coefficient under different mounting and dismounting conditions (Table 9.1)de : Effective interference (mm)B : Nominal inner ring width (mm)d : Nominal bearing inner diameter (mm)di : Inner ring average outer diameter (mm) In the case of other bearings, here D: Bearing nominal outer diameter (mm) Table 9.1 Coefficient conditions fk (average) inner ring pressure for different mounting and dismounting conditions Into the cylindrical solid shaft 39 Pull out the inner ring 59 from the cylindrical solid shaft Note) This value is the value when the inner diameter of the bearing and the surface of the shaft are coated with a thin layer of lubricating oil.