Discussion on several techniques and precautions for bearing installation (interference assembly) (bearing heater) Techniques and precautions for shaft bearing installation (interference assembly)
The correct installation of the bearing directly affects the accuracy, life and performance of the bearing.
⒈Using copper rods and manual strike installation
This is an easy way to install small and medium-sized bearings. When the inner ring of the bearing has a tight fit and the outer ring has a loose fit, place the copper rod close to the end face of the inner ring of the bearing, directly hit the copper rod with a hammer, and transfer the force through the copper rod to install the bearing on the shaft. When the inner ring of the bearing is large, use a copper rod to strike hard evenly around the end surface of the inner ring of the bearing. .
⒉The use of sleeve installation This method is the same as the use of copper rods to install bearings. It is to press the sleeve directly on the end surface of the bearing (the end surface of the inner ring is pressed when the bearing is installed on the shaft; the end surface of the outer ring is pressed when installed in the housing hole), and the striking force of the hand hammer can be evenly distributed on the installation The entire bearing end face of the bearing is used in conjunction with the press, saving labor and time, and reliable quality. The sleeve used for installation should be made of soft metal (either copper or low carbon steel pipe). If the bearing is installed on the shaft, the inner diameter of the sleeve should be slightly larger than the 1-4mm of the journal, and the outer diameter should be slightly smaller than the diameter of the flange of the inner ring of the bearing, or the thickness of the sleeve should prevail, and the thickness should be made equal to the thickness of the inner ring of the bearing 2 / 3-4 / 5, and both ends of the sleeve should be flat and perpendicular to the barrel. If the bearing is installed in the seat hole, the sleeve outer diameter should be slightly smaller than the bearing outer diameter.
⒊ There is also a press press method: the installation pressure should be directly applied to the end surface of the interference fit bearing ring, otherwise it will cause pressure damage on the bearing working surface and cause the bearing to be quickly damaged.
4. Heating installation
For the installation of bearings with large interference or large-size bearings, in order to facilitate installation, the principle of thermal expansion and contraction can be used, and the bearings are heated in the oil tank and then installed with copper rods, sleeves and hand hammers. The temperature during heating is generally controlled below 100 ° C, and 80-90 ° C is more suitable. When the temperature is too high, it is easy to cause the bearing ring raceway and rolling body to anneal, affecting the hardness and wear resistance, resulting in reduced bearing life and premature scrap.
The fit between the bearing and the shaft is generally a transition fit, and the fit between the seat ring and the bearing seat hole is generally a clearance fit. The center shaft ring of the bidirectional bearing should be fixed on the shaft to prevent rotation relative to the shaft. The installation method of the bearing is generally the rotation of the shaft, so the cooperation between the inner ring and the shaft is an win-win fit, and the cooperation between the outer ring of the bearing and the bearing chamber is a clearance fit.
When installing the bearing, first fix the dial indicator to the end surface of the box shell, so that the contact of the meter is on the bearing shaft ring raceway and rotate the bearing. While rotating, observe the pointer of the dial indicator. If the pointer deflects, the shaft ring and The axis centerline is not vertical. If the hole of the case is deep, you can also use the extended dial gauge to check. This is a good way to check the perpendicularity of the shaft ring and shaft centerline.
Bearing installation is reversed, not only does the bearing work abnormally, but the mating surfaces will be severely worn. Since the difference between the shaft ring and the seat ring is not obvious, extreme care should be taken during assembly to prevent reverse mounting. When it is installed correctly, its seat ring can automatically adapt to the rolling of the rolling body, ensuring that the rolling body is located in the upper and lower raceways. In addition, there should be a 0.2-0.5mm gap between the bearing ring and the bearing seat hole to compensate for errors caused by parts processing and installation, when the center of the bearing ring is offset , This gap can ensure its automatic adjustment, avoid contact friction, and make it operate normally. Otherwise, it will cause severe damage to the bearing.
Precautions during installation: 1. For IKO imported bearing rings with clearance fit, it is recommended to apply a thin layer of anti-creep corrosive agent on the mating surface to prevent frictional corrosion between the mating surfaces.
2. The force applied to the bearing during installation must not be transferred from one bearing ring to another through the rolling element, otherwise it may cause damage to the raceway. However, under no circumstances should you directly strike the bearing rings, cages, rolling elements or seals.
3. Install eccentric sleeve. First put the eccentric sleeve on the eccentric step of the bearing inner sleeve, and tighten it by hand along the rotation direction of the shaft. Then insert or hold the small iron rod into the countersink hole. Use a hammer to strike the iron rod in the direction of rotation of the shaft. Make the installation of the eccentric sleeve firm, and then tighten the hexagon socket screws on the eccentric sleeve.
4. Don't tighten the bolts to fix the bearing housing first, let the bearing casing turn in the bearing housing. Then tighten the bearing seat bolts. Also install the other end bearing and seat on the same shaft, turn the shaft a few times, and let the bearing itself find the correct position automatically.
5. Apply lubricating oil to the mating surfaces of the bearing housing and the bearing, and install IKO imported bearings into the bearing housing. Then put the assembled bearing on the shaft together with the bearing seat. Push to the desired location to install.
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