1. Install precision Japanese NSK bearings correctly
For the installation of precision Japanese NSK bearing products, some things should be paid attention to after installation. If it is not installed properly, the life of Japanese NSK bearings will not be long. Therefore, if you want to install Japanese NSK bearings, you should know how to install Japanese NSK bearings yourself, so as to ensure that Japanese NSK bearings are damaged during the installation process. Let me introduce the comprehensive verification method of Japan NSK bearing installation accuracy:
Measure the size of the shaft and the Japanese NSK bearing housing hole to determine the matching accuracy of the Japanese NSK bearing. The matching requirements are as follows:
(1) The inner ring and the shaft adopt an interference fit, and the interference is 0～+4μm (0 under light load and high precision);
(2) The outer ring and the Japanese NSK bearing seat hole adopt clearance fit, the clearance amount is 0～+6μm (but when the free end Japanese NSK bearing uses angular contact ball bearings, the clearance can be increased);
(3) The roundness error of shaft and seat hole surface is 2μm
(4) The parallelism of the end face of the spacer ring used in Japanese NSK bearings is 2μm
(5) The runout between the inner end of the shaft shoulder and the outer end face is 2μm
(6) The runout of the shoulder of the Japanese NSK bearing seat hole to the axis is 4μm
(7) The inner end of the front cover of the spindle faces the axis with a runout of 4μm.
Click here for more information about NSK Bearing HR33014J.
2. Anti-rust method
The surface pretreatment method of the rust-proof object:
1) Surface cleaning: The cleaning method must be selected according to the nature of the surface of the rust-prevented object and the prevailing conditions. Commonly used are solvent cleaning method, chemical treatment cleaning method and mechanical cleaning method.
2) After the surface is dried and cleaned, it can be dried with filtered dry compressed air, or dried with a dryer at 120~170℃, or dried with clean gauze.
Method of applying anti-rust oil
1) Soaking method: Some small Japanese NSK bearings are immersed in anti-rust grease to make the surface adhere to a layer of anti-rust grease. The thickness of the oil film can be achieved by controlling the temperature or viscosity of the anti-rust grease.
2) The brushing method is used for outdoor construction equipment or products with special shapes that are not suitable for immersion or spraying. When brushing, it is necessary to pay attention not to accumulate, but also to prevent leakage.
3) Spray method Some large anti-rust objects cannot be oiled by immersion method. Generally, use filtered compressed air with a pressure of about 0.7Mpa to spray in a clean air place. The spray method is suitable for solvent-diluted anti-rust oil or thin-layer anti-rust oil, but complete fire protection and labor protection measures must be adopted.
Whether the installation of Japanese NSK bearings is correct or not affects the accuracy, life and performance. Therefore, the design and assembly department must fully study the installation of Japanese NSK bearings. Hope to install in accordance with operating standards. The work standard items are usually as follows:
(1) Clean Japanese NSK bearings and related parts of Japanese NSK bearings
(2) Check the size and finishing of related parts
(4) Inspection after installation of Japanese NSK bearings
(5) Supply lubricant
Just before the installation, the Japanese NSK bearing packaging was opened. General grease lubrication, do not clean, directly filled with grease. Lubricating oil is lubricated, and cleaning is not usually necessary. However, for instruments or high-speed bearings from Japan NSK, they must be cleaned with clean oil to remove the anti-rust agent coated on the bearings of Japan NSK. The Japanese NSK bearing with the anti-rust agent removed is easy to rust, so it cannot be left alone. In addition, Japanese NSK bearings that have been sealed with grease can be used directly without cleaning.
The installation method of NSK bearings varies with the structure, fit and conditions of NSK bearings in Japan. Generally, because most of the shaft rotates, the inner ring needs an interference fit. Cylindrical hole Japanese NSK bearings are usually pressed in with a press or hot-packed. In the case of a tapered hole, install it directly on the tapered shaft or use a sleeve.
When installing to the shell, generally there is a lot of clearance fit and the outer ring has an interference. It is usually pressed in with a press, or there is also a shrink fit method for installation after cooling. When dry ice is used as the coolant, the moisture in the air will condense on the surface of the Japanese NSK bearing when the shrink fit is installed. Therefore, appropriate anti-rust measures are required.