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Shanghai Shang Shaft Bearing Quality Inspection Institute Co., Ltd.

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Address: 301 Shangxue Road, Jiading District, Shanghai

Several matters needing attention in the assembly and disassembly of precision bearings

2021-01-29 14:26

Installation and installation tools for precision bearings

Spindle, screw with precision bearings as the basic parts of the machine tool, its performance directly affects the machine's speed, rotary accuracy, rigidity, anti-chattering vibration cutting performance, noise, temperature rise and thermal deformation, etc., thereby affecting the accuracy of the machined parts, Surface quality, etc.

1.precision bearingInstallation Precautions

1. The precision bearing assembly site should be kept as clean as possible;
2. Avoid the pollution of precision bearings or the entry of foreign bodies, which have a great adverse effect on the operation and service life of the bearings;
3. Check the geometric accuracy, dimensional accuracy and cleanliness of the bearing seat hole and the mating surface on the shaft;
4. When installed in the ring with the surface coated with a little oil or a little grease, precision bearings easier to install to the design site;
5. There should be a 100~150 installation guide chamfer when designing the bearing seat hole and shaft;
6. Do not over-cool the bearing, because condensation can lead to corrosion of the bearing and the bearing's mating surface;
7. Bearing inner ring and spindle assembly need to use directional assembly method or angle selection method, that is, artificially control the direction of radial runout error of each assembly, so that the error offset each other rather than cumulative;
8. After the bearing is pressed into the bearing, it shall rotate flexibly without blocking;
9. After installation, check whether the precision bearing system is operating properly.
2. reasonable use of installation tools

When the amount of interference is large, can use heating box, oil bath heating or inductor heating bearings to install, heating temperature range of 80 ℃ ~ 100 ℃, the maximum can not exceed 120 ℃. At the same time, the application of nuts or other appropriate methods to tighten the bearing to prevent the width of the bearing after cooling contraction and the gap between the ring and the shaft shoulder.

When the bearing is installed, equal pressure must be exerted on the circumference of the end face of the ferrule, and the ferrule must be pressed in. Tools such as a hammer must not directly knock the end face of the bearing to avoid damage. In the case of a small amount of interference, you can press the end face of the bearing ring with a sleeve at room temperature, tap the center of the assembly sleeve with a hammer, and press the ring evenly through the sleeve. The assembly force must not be transmitted through the rolling body to avoid direct hammering of the bearing ring. When pressing, ensure that the end face of the outer ring and the end face of the shell shoulder, and the end face of the inner ring and the end face of the shaft shoulder are pressed tightly, and no gap is allowed.

When using mechanical press or hydraulic press, the assembly sleeve must be used for press fitting, and it must be kept in a horizontal state. If there is inclination, the bearing channel will be damaged due to force, resulting in abnormal noise of the bearing. The assembly sleeve should completely contact the entire circumference of the end face of the inner or outer ring of the bearing.

 Disassembly of precision bearing 
The designer should consider the disassembly problem at the installation part of the precision bearing. In general, the precision bearing is installed with interference fit. In the design, the shaft or the bearing seat hole should be provided with a disassembly groove to facilitate the disassembly of the bearing.
If the disassembled precision bearing is to be reused, the disassembly process should be handled carefully. Attention should be paid to the following points when disassembling the precision bearing: avoid directly hitting the bearing ring; the disassembly force should not be transmitted through the bearing rolling element; when disassembling the precision bearing from the shaft, the disassembly force should be transmitted through the bearing inner ring; when disassembling the precision bearing from the bearing seat hole, the disassembly force should be transmitted through the bearing outer sleeve; once the precision bearing is disassembled, it should be cleaned, dried and coated with anti-rust oil or grease to avoid corrosion.

If you pay attention to the above points during the assembly and disassembly of precision bearings, it will have an ideal effect on the control of the spindle temperature rise, the high-precision high-speed trouble-free operation of the spindle, and the control of transmission accuracy.