Bearings are an important part of all machinery, and their quality is related to the operating conditions of the entire equipment. This article introduces the installation, maintenance, disassembly and common problems of the bearings.
Bearing installation
Bearing installation directly affects the accuracy, service life and performance. Therefore, the design and assembly department should fully study the bearing installation according to the following operation standards:
(1) Clean the bearing and bearing related parts;
(2) Check the size and finishing of the related parts;
(3) Installation (just before installation, open the bearing package);
(4) Inspection after the bearing is installed;
(5) Supply lubricant.
Lubricating grease is generally lubricated, directly filled with grease without cleaning. Lubricating oils do not need to be cleaned, but bearings for instruments or high-speed bearings should be cleaned with clean oil to remove the anti-rust agent applied to the bearings. Bearings with the anti-rust agent removed are prone to rust, so they cannot be left alone. Furthermore, bearings that have been sealed with grease are used without cleaning. Bearing installation methods vary depending on the bearing structure, fit, and other conditions. Generally speaking, because most of the shaft rotates, the inner ring needs an interference fit. Cylindrical bore bearings are usually pressed in with a press or hot-packed. In the case of tapered hole bearings, install it directly on the tapered shaft, or install it with a sleeve.
Installation of cylindrical bore bearing
(1) Method of pressing in
Pressing in the method is widely used for small bearings. Put the cushion block into the inner ring and press it quietly to the inner ring with a press until it contacts the shaft shoulder closely. Installing the pad on the outer ring to the inner ring is the cause of indentations and injuries on the raceway, so it is absolutely forbidden.
During operation, oil can be applied to the mating surface in advance. In the event that the hammer must be used for installation, the inner ring must be padded. This method is only limited to the case of small interference, and cannot be used for large interference, or medium and large bearings. For non-separable bearings such as deep groove ball bearings, where both the inner ring and the outer ring need to be installed with an interference amount, use a pad to compress the inner ring and the outer ring at the same time with a screw or oil pressure. The outer ring of the self-aligning ball bearing is easy to tilt, even if it is not an interference fit, it is best to install it with a block.
Separate bearings, such as cylindrical roller bearings and tapered roller bearings, can install the inner ring and outer ring respectively on the shaft and the outer shell. When combining the separately installed inner ring and outer ring, the key is stability Close the two together so that the center of the two does not deviate. Barely pressing in will cause the raceway surface to get stuck.
(2) Hot-mounting method
Large bearings require a lot of force when pressed in, so it is difficult to press in. For this reason, hot mounting methods that heat bearings in oil to expand them and then install them on a shaft are widely used. Using this method, the work can be completed in a short time without adding undue force to the bearing.
Bearing heating temperature is based on bearing size and required interference. The precautions for hot-fitting operations are as follows:
(a) The bearing shall not be heated to above 120 ℃;
(b) In order to prevent the bearing from directly contacting the bottom of the oil tank, it may be considered to place the bearing on a metal mesh platform or hang the bearing;
(c) Heat the bearing to 20 ℃ -30 ℃ higher than the required temperature, so that the inner ring will not become cold during operation and it is difficult to install;
(d) After installation, the bearing cools down and shrinks in the width direction, so use a shaft nut or other suitable method to tighten it to prevent a gap between the inner ring and the bearing shoulder.
Please check the Product Guide to select suitable bearings for your machinery.
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