Project Description

Oilless Bearings services

Quality Inspection And Life Evaluation | Self Lubricating Bearings

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  • High hardness, wear-resistance, and fully comply with EU ROHS standards. Can provide spectrometer composition test, strength test.


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  • High hardness, wear-resistance, and fully comply with EU ROHS standards. Can provide spectrometer composition test, strength test.


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  • High hardness, wear-resistance, and fully comply with EU ROHS standards. Can provide spectrometer composition test, strength test.


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oilless bearing



Self-Lubricating Plain Bearings | VIIPLUS

Self-lubricating bearings, as the name suggests, provide their own lubrication during operation without requiring the application of grease or oil lubricants.

The benefits of oilless bronze bearings

Quality Inspection And Product Verification

Through the use of a video microscope, dimensional including roundness, radius, & roughness (Ra), hardness, torque, and digital noise/vibration VIIPLUS has the means to verify bearings boundary and internal dimensional characteristics.

To further ensure that product is exactly the quality level and specifications required, VIIPLUS’s Engineering Department works closely with its customers’ technical & engineering departments to provide assistance with bearing selection, proper lubricant, mounting, documentation including CAD files, and elimination of stack-up-tolerance issues.

self lubricating bearing
low friction cast bronze bearing


Oilless Bearing – Accurate Industrial Solutions

As a kind of sliding bearing, the self-lubricating bearing is widely used in aviation due to its characteristics of no need to add lubricating oil (grease), simple structure, high working load, and high-temperature resistance, corrosion resistance, low friction coefficient, low pollution, and low noise. It is used in hinge joints, cantilever devices, conveyor belts, and other devices in the fields of aerospace, heavy machinery, weapon equipment, water conservancy facilities, etc.

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Bronze Bushing

Self-lubricating bearings | China Supplier

Measurable & Sustainable Results – To Help You Meet Operational Goals

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The benefits of oilless bronze bearings

Bearing Test And Quality Control System

Technical appraisal of the state of self-lubricating bearings, also known as bearing detection, is a technical means to assess whether self-lubricating spherical plain bearings can be used. Usually, the bearing’s external dimensions, rotation accuracy, appearance, hardness, static load rating, dynamic load rating, limit speed, friction torque, and pad bonding quality are tested.

flange oilless bearing
self lubricating sleeve bushings

Life Evaluation Of Self-Lubricating Spherical Plain Bearings

The commonly used self-lubricating bearings are especially suitable for some parts of the main engine that do not allow adding lubricants or are not frequently replaced due to their low friction coefficient, low wear degree, long service life, no need for external lubricants, and no maintenance. However, due to the complex working environment, large load, insufficient self-lubrication, and other reasons, it is easy to cause excessive wear of the bearing.

The life of the bearing is not only related to the lubricating material itself but also affected by many external factors:

such as speed, temperature, load, swing amplitude, swing frequency, etc. The better the wear resistance of the material and the lower the coefficient of friction, the longer the life. The temperature coefficient, load coefficient, swing amplitude coefficient, swing frequency coefficient, and sliding coefficient are all proportional to the service life, that is, when the temperature increases, the load, swing amplitude, swing frequency, and sliding speed increase, it will aggravate the wear of the bearing and cause its wear and tear. Lifespan is reduced. Today, with the vigorous development of space technology, people are not only satisfied with the environmental field of the earth, but also extend the research field to outer space. In addition to conventional influencing factors, ultra-high vacuum, irradiation, atomic oxygen, cosmic dust, microgravity, etc. are also necessary considerations.

Quality Inspection

1. Appearance and precision inspection

The inspection of the appearance of self-lubricating bearings is closely related to the accuracy, performance, and life of the bearing. It is usually carried out under astigmatism. The following points need to be paid attention to in the visual inspection:

  • (1) Various cracks, such as original material cracks, forging cracks, heat treatment cracks, grinding cracks, etc., these cracks may occur during the operation of the bearing. It will form a source of stress concentration and expand rapidly until the bearing ruptures, which greatly affects the service life and safety performance of the self-lubricating bearing. For bearings in critical parts, radiographic inspections or 100% magnetic inspections are usually performed on their components.
  • (2) Various mechanical scars, such as scratches, abrasions, crushes, bumps, etc., these scars are likely to cause eccentric load and stress concentration of the bearing, which will eventually lead to the decline of its rotation accuracy and service life.
  • (3) Corrosion, black skin, and pitting, the latter two defects are easy to cause the accumulation of water and pollutants, which will further develop into rust, and rust will affect the installation of the bearing, and it is also a pollution source of fatigue damage. Serious rust will make the bearing. invalid
  • (4) Peeling and folding will cause the local and bearing matrix to be not firmly bonded, and there are usually different degrees of carbon depletion or decarburization around it, which is easy to cause the surface of the matrix to be dented, worn or slumped, which will affect the life of the bearing. Accuracy matters
  • (5) According to the regulations, there should be no visible burns (annealing marks) on the surface of the bearing during assembly.

2. Testing Of Bearing Materials

Testing of bearing materials includes testing of material hardness and residual magnetism, as well as testing of pad bond strength for self-lubricating bearing designs.

3. Testing Of Load-carrying Capacity And Tribological Properties

With the continuous improvement of the requirements for precision bearings in various countries in the world, the testing of bearings has shifted from dimensional accuracy, geometric accuracy, rotational accuracy, etc. to the dynamic performance of bearings, such as the testing of bearing capacity and tribological performance. Among them, the detection of bearing capacity includes rated (dynamic) static load, friction torque, and vibration detection.

The friction resistance of self-lubricating bearings is directly related to the bearing life, which can affect the reliability and accuracy of the main machine guidance system. Vibration can easily cause local damage to bearings, extrusion of solid lubricants, and noise. Therefore, with the continuous advancement of testing equipment and technology, the measurement of bearing friction torque and vibration has become two important technical performance indicators.