Installation and disassembly of printing machine bearings
The installation guide printing machine bearing is a high-precision mechanical unit. Be careful before and during installation. The function and service life of the bearing also depend on careful installation. Delivery status and storage The bearings of the printing press are protected by mineral oil-based anti-rust oil. Pre-filled grease and sealed bearings, its storage period depends on the shelf life of the grease and the material of the sealing ring. Bearings should be stored in a dry, clean room, the temperature is as constant as possible, and the relative humidity should not exceed 65%. Sweat will cause corrosion when removing the package: Keep your hands clean and dry. Safety gloves must be worn. The original package of the bearing can be removed only when installing it. According to the different situations of each printing machinery manufacturing company, there are many installation methods that can be adopted. This method of cooling bearings is often applied to the installation of tapered bore bearings that are tightly fitted with wall plate holes. The bearing unit with the inner ring removed can be directly installed into the wall plate hole by hand without installation tools after cooling treatment. Then install the inner ring together with a suitable spacer. Cooling the bearing will cause condensation to form on the bearing. In order to avoid corrosion, bearings and wall plate holes should first be sprayed with high-efficiency mineral base oil anti-rust oil. Press-fitting at room temperature In addition, it is also possible to press-fit the bearing safely at room temperature. In order to overcome the press-in force, a suitable installation tool specially matched with the bearing and the printing machine is required. In order to prevent bearing damage caused by incorrect installation, we recommend that the installation process and the operation of the installation tools be approved by the Schaeffler Group engineering service department. In this way, up to four rings of printing press bearings fitted on the cylindrical shaft and tightly fitted with the wall plate holes can be installed safely and economically. Disassembly: For tapered bore bearings, the inner ring can be released from the shaft hydraulically. The outer ring of the bearing or the outer ring assembly of the three-ring and four-ring bearing can be removed from the wall plate with a suitable unwinding tool. The dimensions of the retaining ring and the retaining shoulder of the eccentric ring have been determined to ensure that the bearing will not be damaged due to this. When the cylindrical bore bearing is disassembled, the inner ring can be disassembled at the same time. This is very important because these bearings are often preloaded and the raceways can be easily damaged if they are disassembled separately. Cylindrical roller bearing clearance adjustment Cylindrical roller bearings with tapered bores can achieve clearance, zero clearance or preload after installation. It requires specific steps and equipment to measure the envelope circle of the rolling element. The advantage of this method is that the working clearance is adjusted extremely accurately, with a tolerance of 1 m. Cylindrical roller bearing installation process In the following example, the installation process of cylindrical roller bearings N10 and NN30 with a separable outer ring with a tapered inner bore and the enveloping circle measuring instrument MGA 31 will be introduced. This measuring instrument is used to precisely adjust the internal radial clearance or preload of cylindrical roller bearings. Step 1 Use a conventional inner diameter gauge to measure the raceway diameter of the outer ring after installation, as shown in Figure 1. Step 2 Transfer the measured diameter to the two quenched and finely ground measuring surfaces of the enveloping circle measuring instrument, as shown in Figure 2. Step 3 Then, place the enveloping circle tester on the inner ring and roller cage assembly that has been pre-installed on the tapered shaft, as shown in Figure 3. Step 4 Push the bearing axially until the dial gauge of the enveloping circle gauge shows the required internal radial clearance or preload. Then, use a block gauge to measure the distance from the inner ring of the bearing to the shoulder at 4 measuring points separated by 9 on the circumference, as shown in Figure 4. Remove the inner ring of the bearing, grind the width of the spacer ring according to the distance determined above, and install it on the shaft. Finally, install the bearing inner ring again and lock it with a nut. Adjusting the clearance without a gauge. If there is no enveloping circle measuring instrument, the clearance can be adjusted more accurately by measuring the radial change of the bearing clearance with a dial gauge. This method is not as accurate as using an enveloping circle gauge, but it is generally sufficient. We recommend that you discuss with the engineering service department of the Schaeffler Group to determine the most technically suitable and economical method for a specific application. Industrial installation services The Schaeffler Group provides high-quality products, services and training for various types of bearing arrangements. Industrial installation services include: installation and disassembly of all types of rolling bearings, inspection and confirmation of adjacent parts (shafts and bearing seats), maintenance and inspection of bearings, analysis of poor operation of bearings, rationalization suggestions for installation operations, and the design and manufacture of special tools. Equipment rental If users only occasionally need special installation and measurement equipment, such as maintenance, they can rent these equipment from the Schaeffler Group on a weekly basis. If bearings are rarely installed, renting taper and enveloping circle measuring instruments and heaters may be a more economical alternative to purchasing. Other information For detailed information about industrial services and products, please refer to catalog IS1, 'Rolling Bearing Installation and Maintenance'. Measurement and inspection of high-precision bearings. Measuring instruments and heating equipment for installation can be purchased through the Schaeffler Group. In some cases, these equipment can also be leased. Enveloping circle measuring instrument MGI21 This enveloping circle measuring instrument is used to adjust the internal radial clearance of a cylindrical roller bearing with a separable inner ring. Suitable for cylindrical roller bearings NU4920-K to NU4948-K and NNU4920 to NNU4948. Bearings with a separable inner ring in diameter from 100 mm to 240 mm. The enveloping circle measuring instrument MGI21 measures the inner enveloping circle of the roller and cage assembly through two hardened and finished measuring surfaces, one of which is movable, as shown in Figure 5. After installing the outer ring, place the measuring instrument in the enveloping circle of the roller and cage assembly.