If you want to use precision bearings well, you must first install them!

    If you want to use precision bearings well, you must first install them!

　　 With the rapid development of numerical control technology, "composite, high speed, intelligence, precision, and environmental protection" has become the main trend in the development of today's machine tool industry technology. Among them, high-speed machining can effectively improve the machining efficiency of the machine tool and shorten the machining cycle of the workpiece, which requires the spindle of the machine tool and its related parts to meet the requirements of high-speed machining.

　　Similarly, the precision bearings assembled on the spindle and feed part of the high-precision and high-speed CNC machining center must meet the machine's high-precision, high-speed, low-noise, trouble-free, and high-reliability requirements. The assembly quality of precision bearings directly affects their working conditions and service life. Many failures of CNC machining centers are caused by improper assembly of bearings. Therefore, adequate attention should be paid to the assembly technology of precision bearings.

The assembly points of high-speed precision bearings are briefly described as follows:

一. Removal and cleaning of precision bearings

1. Keep your hands clean and dry

　　 When the precision bearing is taken out of the package, the operator's hands should be kept clean and dry, because sweat on the hands can cause rust, and gloves can be worn if necessary.

2. Ensure good lubrication effect

　　The precision bearing that is taken out should be greased and oiled immediately, and the greased precision bearing should be installed without pollution immediately after being removed, and no grease or oiling treatment should be performed. Grease must be added to the gap between the cage and the outer ring of the bearing during grease loading. It is better to grease up to 30% of the cavity for precision bearings, and grease up to 20% of the cavity for high-speed precision bearings.　　

3. The packaging should be sealed

　　Precision bearings can only be removed from the original packaging for cleaning before assembly. After taking out several sets of precision bearing packages sealed with volatile corrosion inhibitors, the packages should be sealed immediately, because the protective gas of VIC paper can only be kept in the sealed package.　　

4. Clean properly

　　 Grease precision bearings must not be cleaned before assembly, and precision bearings without grease must be cleaned before assembly. After cleaning, they should be dried and immediately applied with anti-rust oil or grease to avoid corrosion.

The following cleaning agents can be used for degreasing and cleaning precision bearings: Aqueous cleaning agent-neutral, acidic or alkaline cleaning agent, check the compatibility of the alkaline cleaning agent with aluminum parts before cleaning; organic cleaning agent-acid and Anhydrous kerosene, light gasoline (non-auto gasoline), Freon 12 substitutes or chlorine-containing hydrocarbon cleaning agent.

　　Precision bearing cleaning must pay attention to the following matters: environmental protection, health and work safety; the operation method of cleaning agent must follow the product description to avoid danger.　　

二.Installation and installation tools of precision bearings

Precision bearings for spindles and screws are used as the basic parts of the machine tool. Their performance directly affects the speed, rotation accuracy, rigidity, anti-vibration cutting performance, noise, temperature rise and thermal deformation of the machine tool, and then affects the accuracy of the machined parts. , Surface quality, etc.　　

1. Precautions for precision bearing installation

The precision bearing assembly site should be kept as clean as possible; avoid contamination of the precision bearing or the entry of foreign matter, which has a great adverse effect on the operation and service life of the bearing; check the geometric accuracy, dimensional accuracy and dimensional accuracy of the bearing seat hole and the mating surface on the shaft Cleanliness; apply a little oil or a little grease on the mating surface of the ring during installation, so that the precision bearing is easier to install to the design position; when designing the bearing housing hole and shaft, there should be a 100-150 installation guide chamfer; do not over-cool Bearings, because of condensation can cause the bearing and its mating surface to rust; the inner ring of the bearing and the main shaft must be assembled by the directional assembly method or the angle matching method, that is, the direction of the radial runout error of each assembly is artificially controlled to make the error mutual Offset rather than accumulate; after the bearing is pressed into the bearing, it should rotate flexibly without a sense of blocking; after the installation is completed, check whether the precision bearing system is operating normally.　

2. Reasonable use of installation tools　

　　(1) When the interference is large, it can be installed by heating box, oil bath heating or induction heating bearing. The heating temperature range is 80℃～100℃, and the maximum should not exceed 120℃. At the same time, use nuts or other appropriate methods to tighten the bearing to prevent the bearing from shrinking in the width direction after cooling and causing a gap between the ring and the shaft shoulder.

　　(2) When installing the bearing, equal pressure must be applied to the circumference of the end face of the ferrule to press the ferrule in. It is not allowed to directly knock the end face of the bearing with a tool such as a head to avoid damage. In the case of small interference, the end face of the bearing ring can be pressed with a sleeve at room temperature, and the center part of the assembly sleeve can be tapped with a shank head, and the ring can be pressed in evenly through the sleeve. The assembly force must not be transmitted through the rolling elements to avoid direct hammering of the bearing ring. When pressing, make sure that the end face of the outer ring and the end face of the housing 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.　

　　(3) When using a mechanical press or a hydraulic press, the assembly sleeve must be used for press-fitting, and ensure that it is in a horizontal state. If it is tilted, the bearing channel will be damaged due to force, and the bearing will produce abnormal noise. The assembly sleeve must be in full contact with the entire circumference of the end face of the inner ring or outer ring of the bearing.　

三. Disassembly of precision bearings

　　 Designers should consider disassembly when installing precision bearings. In general, precision bearings are installed with interference fit. When designing, the shaft or bearing seat hole should be provided with a disassembly groove to facilitate the removal of the bearing.　　

　　 If the disassembled precision bearing is to be reused, the disassembly process must be handled with care. Pay attention to the following points when disassembling precision bearings: Avoid direct hitting the bearing ring; the disassembly force should not be transmitted through the bearing rolling elements, and the disassembly force should be transmitted through the bearing inner ring when disassembling the precision bearing from the shaft, from the bearing housing hole When removing the precision bearing, the disassembly force should be transmitted through the bearing housing; once the precision bearing is disassembled, it should be cleaned, dried, and then coated with anti-rust oil or greased to prevent the bearing from being rusted.

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

 Attach P4 precision bearing  series table