Follow me on: 
How To Choose Miniature Bearings
Miniature bearings are an important component used to reduce friction and support mechanical loads. They play a vital role in various equipment and machines, including precision instruments, micro motors, household appliances, medical equipment, power tools, and fitness equipment. , fishing gear, remote control toys and other fields. In this blog, we will introduce in detail the advantages, types, materials, dimensions and causes of failure of miniature bearings, and summarize some tips for selecting miniature bearings. We hope you can better understand and apply miniature bearings.
Miniature bearings are typically manufactured with very tight tolerances and high-quality materials to ensure they can withstand high speeds and loads while maintaining accuracy and precision. It is suitable for applications requiring high speed rotation, low friction torque, low vibration and low noise. One of the main characteristics of miniature bearings is their size. They are usually smaller than standard bearings and can have an outer diameter as small as a few millimeters. For the metric series, the outer diameter is less than 9mm; for the inch series, the outer diameter is less than 9.525mm for various small bearings. This small size allows for a compact and lightweight design, making it ideal for applications where space is limited or weight is a concern.
Miniature bearings are mainly made of carbon steel, bearing steel, stainless steel, plastic, ceramics, etc., and the minimum inner diameter can be 0.6mm. Among ultra-small bore miniature bearings, the common types of miniature deep groove ball bearings include 18 types of metric 68 series, 69 series, 60 series, etc., and a total of 6 types of inch R series. On this basis, it can also be divided into bearing series with ZZ steel dust cover, miniature bearing series with RS rubber sealing ring, Teflon bearing sealing ring series and flange rib series, etc.
Advantages of miniature bearings
High precision. Due to the use of high-quality materials and advanced manufacturing processes, its dimensional accuracy and surface quality can reach a high level. For example, miniature bearings made of stainless steel can guarantee long-term operation in the temperature range of -40°C to 150°C without rusting; miniature bearings made of ceramics can be used at high temperatures above 200°C without deformation, etc.
long life. Due to the use of high-quality materials and advanced manufacturing processes, its service life can reach than 1 billion times and its reliability is extremely high (the wear rate is less than 0.1%).
High-speed rotation. Because of its small size and light weight, it does not generate additional dynamic and static loads during rotation; therefore it can be used in high-speed rotation applications.
Types of miniature bearings
Miniature bearings can be divided into the following types according to different uses:
Miniature deep groove ball bearings
Deep groove ball bearings are a widely used type of miniature bearings. They have the characteristics of simple structure, easy manufacturing and installation, long service life, and are suitable for working under high-speed conditions. Deep groove ball bearings can withstand radial and axial loads.
Miniature angular contact ball bearings
Miniature angular contact ball bearings can withstand radial and axial loads. Compared with deep groove ball bearings, angular contact ball bearings have a relatively larger rated load capacity. This bearing is widely used in equipment such as CNC machine tools and high-speed power tools because it is suitable for high-speed rotation and high-precision requirements.
Miniature tapered roller bearings
Miniature tapered roller bearings are the type of bearings that mainly bear radial and axial loads. Its inner and outer conical surfaces are both inclined surfaces. This inclined surface prevents the bearing from deflecting when bearing radial and axial loads. Miniature tapered roller bearings are widely used in heavy machinery and metallurgical equipment and other fields.
Miniature self-aligning ball bearings
Miniature self-aligning ball bearings can produce a certain deflection angle in the bearing and mainly bear large radial loads and certain axial loads. Aligning ball bearings are suitable for vibration and impact load applications, such as steel manufacturing equipment, agricultural machinery and equipment, etc.
Miniature thrust ball bearing is a special separable ball bearing, consisting of a shaft washer, a seat washer and a steel ball with a cage. Usually the material of the two washers and balls is chromium steel, and the material of the cage is brass or stainless steel. If longer corrosion resistance is required, stainless steel thrust bearings are a good choice, with both washers, balls and cages made of stainless steel (SS440). Miniature thrust ball bearings with hybrid ceramic balls are also very popular. Miniature thrust ball bearings cannot bear too much radial load and are only suitable for axial loads. Usually miniature thrust ball bearings and stainless steel thrust bearings are widely used in crane hooks, Vertical water pumps, vertical centrifuges, jacks, low-speed reducers and other occasions that only require one-sided axial load and low speed.
Materials for miniature bearings
In terms of load, miniature bearings are designed to provide reliable high performance at low torque, moderate radial loads and thrust loads. There are many kinds of materials for making miniatures, and we will list them one by one below.
Chrome Steel: Chrome steel is the most common miniature ball bearing material due to its high load capacity and low noise characteristics. Additionally, miniature bearings, also known as instrument bearings, are generally not used in high-load applications.
Stainless steel: The amount of material used in the application is very small, so stainless steel materials are often used to make miniature bearings. 440C stainless steel bearings are designed to provide better corrosion and wear resistance than 52100 steel.
Ceramic: Miniature Ceramic bearings are made of ceramic materials such as silicon nitride or zirconia. They have high stiffness, low friction, and good corrosion and wear resistance. They are often used in high-speed machine tools, electric motors, medical equipment and other applications.
Hybrid: Hybrid bearings are a combination of ceramic balls and steel raceways that offer higher stiffness and less friction than all-steel bearings. They are commonly used in applications such as electric motors, generators and gearboxes.
Causes of miniature bearing failure
About 40% of the failures of miniature bearings are caused by contamination from dust, dirt, debris, and corrosion. Contamination is usually caused by incorrect use and poor use environment, and it can also cause torque and noise problems. Miniature bearing failures caused by the environment and contamination are preventable, and the cause of such failures can be determined by simple visual inspection. As long as the use and installation are reasonable, the erosion of micro bearings is easy to avoid. Denudation is characterized by indentations in the miniature bearing raceways caused by impact loads or incorrect installation. Denudation usually occurs when loads exceed the material’s yield limit. Erosion can also occur if the installation is incorrect so that a load travels across the miniature bearing ring. Pits in miniature bearing rings can also produce noise, vibration and additional torque.
Factors for choosing miniature bearings
Choosing the right miniature bearing for your application is critical to ensuring optimal performance and reliability. There are many factors that need to be considered when selecting miniature bearings to avoid selection errors. Aubearing summarized the guide for selecting miniature bearings.
Determine application requirements for bearings
Before selecting a miniature bearing, it is important to understand the bearing requirements of the application, including load, speed, accuracy and operating environment. Determining this information will help you narrow your choices and select a bearing that meets the requirements of your specific application.
Choose the right bearing type
After determining the application requirements, select the appropriate bearing type. For example, if the application requires high precision, angular contact bearings may be one of the best choices. If the application requires high-speed performance, deep groove ball bearings or ceramic bearings may be a better choice.
Consider bearing materials
Bearing material affects bearing performance and durability. Stainless steel bearings are ideal for applications in harsh environments, while ceramic bearings offer high stiffness, low friction, wear and corrosion resistance. However, ceramic bearings are also generally expensive.
Miniature bearing accuracy
In most cases rolling bearings of normal dimensions and rotational accuracy are sufficient. When requirements are higher, bearings require higher accuracy levels. According to the International Organization for Standardization (ISO) definition, precision bearings are classified into grades P0, P6, P5, P4 and P2. These classes are defined based on the maximum allowable deviation of the inner and outer raceways and rolling elements.
Micro bearing speed
Single-row bearings have particularly low friction and therefore can reach the highest speeds. Such bearings include deep groove ball bearings that can only bear radial loads and angular contact ball bearings that can bear combined loads. Improving the dimensional accuracy, rotational accuracy and mating part accuracy of the bearing, adopting advanced lubrication and cooling methods, and using special forms of cages can all increase the allowable speed of the bearing. Low-noise operation, small motors, office equipment and household appliances generally require low operating noise.
Miniature bearing stiffness
The stiffness of a bearing usually refers to the force required to produce a certain elastic deformation of the bearing. The bearings on the machine tool spindle and pinion shaft require high stiffness. Due to the different contact conditions between rolling elements and raceways, the stiffness of roller bearings is higher than that of ball bearings.
Choose the right bearing supplier
It is crucial to choose a reputable supplier that provides high-quality bearings and provides excellent customer support. Bearing quality. It is necessary to ensure that the quality of the bearings meets the requirements to ensure the safety and efficiency of production. Samples, technical specifications provided by bearing suppliers, and currently delivered products can be inspected to ensure that the products are authentic and reliable. At the same time, you can also ask some companies that you have cooperated with to learn about their experiences and opinions.
Bearing prices. Considering the bearing cost factor, price is also an important factor in selecting suppliers. Through market research, find a bearing supplier with a suitable price. At the same time, you need to pay attention to the hidden costs in price. Such as whether there is a minimum order quantity, whether an advance payment is required and whether there are additional costs.
Leading Time. Delivery deadlines are also a factor to consider when choosing a bearing supplier. In the short term, some companies need to complete production tasks in a shorter period of time, which requires bearing suppliers to deliver goods in time.
Serve. Choosing a reliable bearing supplier also requires considering service. High-quality services can reduce problems in communication, formulation, distribution and other aspects. Not only that, if you encounter some problems during product use, reliable suppliers can also provide you with efficient technical support.
In addition, details such as the material and structure of the cage, the number of rolling elements, clearance and preload force cannot be ignored. At the same time, in order to ensure the normal operation and service life of the bearing, it is also crucial to select the appropriate lubricant and lubrication method. When selecting miniature bearings, it is necessary to comprehensively consider various factors to ensure that they can meet the needs of actual applications and achieve long-term stable operation. If you have any questions about bearings, please do not hesitate to contact Aubearing’s bearing experts to provide you with comprehensive bearing solutions.