Precautions For ZZ Bearing Installation

Time：2021.06.02  Source：Roller Bearings Suppliers

Whether the ZZ bearing is installed correctly will directly affect the accuracy, life and performance of the bearing during use.

Cleaning preparation before installation

(1) When cleaning a large number of ZZ bearings, first use hot machine oil at a temperature of 90～100℃ to melt the encapsulating oil. At the same time, use a seamless and chip-free tool to dig out all the old oil, and then blanch it for a few minutes. Then rinse with kerosene to remove the engine oil, and finally clean it again with gasoline. After cleaning, wear film gloves and place the ZZ bearing on a clean cloth or paper on the workbench to dry.

(2) Before the ZZ bearing is installed, you should use appropriate measuring tools to check the machining quality of the shaft, seat hole and related parts (such as dimensional accuracy, shape accuracy, surface roughness, etc.) according to the technical requirements on the design drawings.

(3) Open the ZZ bearing package before installation, immerse it in the above-mentioned gasoline and other liquids and rotate it gently by hand to ensure that the cage, rolling elements and the sealing oil on the surface of the raceway are thoroughly cleaned.

(4) The assembly surface should be cleaned with clean gasoline, kerosene, toluene or xylene and other solutions, and dried with a clean cloth, and then coated with a thin layer of lubricating oil, which will make the installation and operation more convenient.

(5) Note that ZZ bearings with seals cannot be cleaned by this method, and the inside of the seal should be kept intact and cannot be cleaned.

(6) If there are bumps, burrs, rust spots or solid particles (such as abrasive debris, sand, mud) on the assembly surface of the shaft and the bearing seat hole, it will not only make the installation of the ZZ bearing difficult and make the installation position incorrect, but also If solid particles fall into the ZZ bearing, it will have a grinding effect. When the ZZ bearing rotates, it will scratch or scratch the working surface of the ZZ bearing. Therefore, it must be carefully checked before installation. If the above defects are found, they should be corrected. For example, use an oil file to remove burrs, raised bumps, and rust spots, and polish with a fine emery cloth. Another example is to clean solid particles and dirt. Click here for more details about ZZ BS2-2219-2CSK.

How to install bearings?

1. Install using copper rods and manual tapping

This is an easy way to install small and medium-sized ZZ bearings. When the inner ring of the bearing has a tight fit and the outer ring has a looser fit, put 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 slowly install the bearing on the shaft. When the inner ring of the bearing is large, you can use a copper rod to strike evenly around the end face of the inner ring of the bearing. Do not strike only one side or excessive force. You should strike symmetrically and gently strike to install it slowly to avoid oblique strikes.

2. Use the sleeve to install

This method is the same as using copper rods to install ZZ bearings. It presses the sleeve directly on the end face of the bearing (pressing the end face of the inner ring when the bearing is installed on the shaft; pressing the end face of the outer ring when it is installed in the housing hole), and the striking force of the hand hammer can be evenly distributed in the installation The bearing on the end face of the entire ring can be used in conjunction with a press, saving labor and time in installation, and reliable in quality. The sleeve used for installation should be made of soft metal (copper or low carbon steel pipe can be used). If the bearing is installed on the shaft, the inner diameter of the sleeve should be slightly larger than the journal 1-4mm, and the outer diameter should be slightly smaller than the rib diameter of the bearing inner ring, or the thickness of the sleeve shall be the same as the thickness of the bearing inner ring. 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 outer diameter of the sleeve should be slightly smaller than the outer diameter of the bearing.ZZ 22228-2CS online, click here to buy this bearing.

3. There is also a press-in method

The installation pressure should be directly applied to the end face of the ZZ bearing ring with interference fit, otherwise, it will cause crushing on the bearing working surface and cause the bearing to be quickly damaged.

4. Heating installation

For installation of ZZ bearings or large-size bearings with large interference, in order to facilitate the installation, the principle of thermal expansion and contraction can be used to install the bearing with copper rods, sleeves and hand hammers after heating in the oil tank. The temperature during heating is generally controlled below 100°C, and 80-90°C is more appropriate. When the temperature is too high, it is easy to cause annealing of the bearing ring raceways and rolling elements, which affects the hardness and wear resistance, resulting in the reduction of bearing life and premature scrapping.

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