1. Install precision Japanese NSK bearings correctly
For the installation of precision NSK bearing products, some things should be paid attention to after installation. If it is not installed properly, the life of the NSK bearing will not be long. Therefore, if you want to install NSK bearings, you should know how to install NSK bearings yourself, so as to ensure that the NSK bearings are damaged during the installation process. Let me introduce the comprehensive verification method of NSK bearing installation accuracy below:
Measure the size of the shaft and the NSK bearing housing hole to determine the matching accuracy of the 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 NSK bearing seat hole adopt a clearance fit, and the clearance is 0～+6μm (but when the angular contact ball bearing is used in the free end of the NSK bearing, 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 used in 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 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,
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 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 special-shaped products 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 clean air. 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.
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The correct installation of NSK bearings affects accuracy, life and performance. Therefore, the design and assembly department must fully study the installation of NSK bearings. Hope to install in accordance with operating standards. The work standard items are usually as follows:
(1) Clean NSK bearings and related parts of Japanese NSK bearings
(2) Check the size and finishing of related parts
(4) Inspection after installing NSK bearings
(5) Supply lubricant
I hope to pack NSK bearing packaging just before installation. General grease lubrication, do not clean, directly filled with grease. Lubricating oil does not need to be cleaned in general. However, NSK bearings for instrument or high-speed use should be cleaned with clean oil to remove the rust inhibitor coated on NSK bearings. NSK bearings with anti-rust agent removed are easy to rust, so they cannot be left alone. Furthermore, NSK bearings packed with grease can be used directly without cleaning.
The installation method of NSK bearing varies with NSK bearing structure, fit and conditions. Generally, since most of the shaft rotates, the inner ring needs an interference fit. Cylindrical hole NSK bearings are usually pressed in by a press or hot-fitted. In the case of a tapered hole, install it directly on the tapered shaft or use a sleeve.
When it is installed to the shell, there is generally a lot of clearance fit, and the outer ring has an interference. It is usually pressed in with a press, or there is 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 NSK bearing. Therefore, appropriate anti-rust measures are required.