Unveiling The Essence Of Sleeve Bearing: Elevating Brand Procurement Excellence

Introduction

Sleeve bearings play a vital role in machinery by promoting various components’ smooth and efficient rotational motion. From the pursuit of aerospace performance to operational efficiency in manufacturing, sleeve bearings have become indispensable components and embody the epitome of precision engineering and long-lasting reliability. They provide support and reduce friction between moving parts, thereby increasing the overall performance and longevity of the equipment.

What Is A Sleeve Bearing?

A Sleeve Bearing, also known as a plain bearing or journal bearing, is a type of bearing that consists of a cylindrical sleeve or bushing. This sleeve is typically placed between a rotating shaft and a stationary support structure, providing a surface for the shaft to rotate smoothly with minimal friction.

The inner diameter of the sleeve is slightly larger than the diameter of the shaft, allowing for a small clearance or gap between the two. Lubrication is often applied to this interface to further reduce friction and wear, ensuring smooth operation and extending the lifespan of the bearing.

Types Of Sleeve Bearing Designs

There are several types of sleeve-bearing designs, each with its own unique features and applications.

• Plain cylindrical sleeve bearings——These are the most basic and widely used type of sleeve bearings. They consist of a simple cylindrical sleeve that supports a rotating shaft or journal. Suitable for moderate loads and speeds.

• Flanged sleeve bearings—— These bearings have one or two flanges (collars) at the ends of the sleeve to provide additional support and prevent axial movement of the shaft. Often used in applications where axial loads are present.

• Thrust Sleeve Bearings——Thrust sleeve bearings are designed to support axial loads. They feature a cylindrical sleeve with a flange or shoulder to accommodate thrust forces.

• Self-Lubricating Sleeve Bearings——Self-lubricating sleeve bearings incorporate materials or additives that provide built-in lubrication, reducing the need for external lubricants.

• Oil-Impregnated Sleeve Bearings——Oil-impregnated sleeve bearings, also known as oilite bearings, are made from porous materials such as sintered bronze or powdered metal.

• Spherical sleeve bearings——These bearings have a spherical or elliptical inner surface that allows for angular misalignment between the shaft and the bearing. Used in automotive king-pin bearings.

• Split sleeve bearings——These bearings are split into two or more sections, allowing for easy installation and removal without the need to disassemble the entire shaft.Used in large equipment or maintenance-intensive applications.

• Composite Sleeve Bearings——Composite sleeve bearings combine different materials to achieve specific performance characteristics, such as enhanced wear resistance, high load capacity, or resistance to extreme temperatures or harsh environments.

Materials Used In Sleeve Bearing

There are many types of sleeve-bearing materials, and each can be selected based on its specific application or specific performance needs.

• Bronze: Bronze is one of the most traditional materials used in sleeve bearings.Offers excellent wear resistance, good thermal conductivity, and corrosion resistance.

• Steel: Steel sleeve bearings offer high strength and durability.For heavy-duty applications where extreme load or wear conditions exist.

• Cast Iron: Cast iron sleeve bearings have good damping performance and resistance to wear and pressure. Commonly used in pumps and compressors.

• Polymer (Plastic): Polymer sleeve bearings, also known as plastic or composite bearings, offer advantages such as low friction, corrosion resistance, and self-lubricating properties.

• Ceramics: Ceramic sleeve bearings are prized for their exceptional hardness, wear resistance, and resistance to corrosion and thermal shock. Materials such as silicon nitride, zirconia, and alumina are used in ceramic sleeve bearings, making them suitable for high-speed and high-temperature applications.

• Powdered Metal Alloys: Powdered metal alloys, such as bronze or iron powders mixed with lubricants and binders, are used to create self-lubricating sleeve bearings. These bearings offer low friction, good wear resistance, and the ability to operate in dirty or abrasive environments without the need for external lubrication.

• Babbitt (White Metal): Babbitt is a soft alloy composed primarily of tin, antimony, and copper. It is often used as a lining material in sleeve bearings due to its ability to embed foreign particles, reduce friction, and provide a cushioning effect between the shaft and the bearing surface.

Benefits Of Sleeve Bearing

As a kind of plain bearing, sleeve bearing has the following main benefits compared with rolling bearings:

• Simple structure and low cost;
• Low noise, small vibration, smooth operation, and accurate positioning;
• Strong ability to adapt to axis displacement and large load-bearing capacity;
• Wide range of applications, no signs of rolling wear， and long life.

Sleeve Bearing Vs Ball Bearing: What Are The Different

In addition to the above benefits, sleeve bearings, and ball bearings also have the following important differences:

1 . Different ways of bearing force Ball bearings carry radial and axial loads through point contact between the ball and the ball bearing; The sleeve bearing carries the main radial load through the hydrodynamic pressure of the liquid lubricating film.

2 . Sensitivity to contaminants Ball bearings are relatively insensitive to contaminant intrusion; Sleeve bearings are extremely sensitive to tiny impurities in lubricating oil, which can easily lead to increased wear.

3 . Maintenance requirements vary Ball bearings have good sealing performance and long maintenance intervals; Sleeve bearings need to be continuously replenished with fresh lubricating oil, which requires a large amount of maintenance work.

4 . Startup feature differences Due to the presence of rolling elements, ball bearings have large rolling resistance when starting; The liquid-lubricated sleeve bearing has less starting resistance.

5 . Critical speed limit Sleeve bearings will encounter problems such as liquid resonance friction when running at high speed, and there is a certain critical speed limit; Ball bearings do not have this limitation.

6 . Differences in application situations Ball bearings have a wider range of applications, but sleeve bearings have unique advantages in certain special occasions such as high loads, high temperatures, and strong corrosion or vibration environments.

In short, there are big differences between the two in terms of structure, working principle, performance characteristics, etc. It is necessary to choose the best bearing form according to specific application conditions.

How Are Sleeve Bearings Lubricated?

The lubrication of sleeve bearings usually uses liquid lubrication. By continuously supplying a sufficient amount of lubricating oil or grease to the gap between the bearing and the journal, a layer of hydrodynamic lubricating film is formed, so that there is no gap between the bearing and the journal. Direct metal contact, thus achieving low friction and low wear working conditions.

The requirements for lubrication are also very strict. The appropriate lubricant type and viscosity grade must be selected, and the appropriate oil supply method and control of the lubrication amount must be adopted to ensure that a hydrodynamic lubricating film of sufficient thickness is continuously formed between the bearing and the journal. This avoids direct metal contact, reduces wear, and extends service life.

Purpose And Function Of Sleeve Bearing

Purpose of a sleeve bearing:

A sleeve bearing is designed to provide a low-friction, smooth rotational interface between a rotating shaft or journal and a stationary housing or support. Its primary purpose is to facilitate the relative motion between these two components while carrying the radial loads and, in some cases, axial loads as well.

Functions of a sleeve bearing:

The main functions of a sleeve bearing are to support the rotating shaft or journal, distribute the applied loads evenly over the bearing surface, and maintain a continuous film of lubricant between the shaft and bearing to minimize wear and friction. Additionally, sleeve bearings can accommodate minor misalignments, absorb shock loads, and dissipate heat generated during operation, ensuring reliable and efficient performance in various mechanical systems.

Common Sleeve Bearing Applications

Sleeve bearings have many common applications in the industry including:

• Mechanical equipment: such as motors, pumps, fans, transmission systems, etc.
• Automobile industry: in automobile engines, gearboxes, steering systems suspension systems, etc.
• Agricultural machinery: Agricultural machinery and equipment, such as tractors, tillage machines, harvesters, etc.
• Aerospace: In the aerospace industry, sleeve bearings are used in critical components such as aircraft engines, landing gear systems, and flight control surfaces.
• Heavy Machinery: In the heavy machinery manufacturing industry, such as excavators, cranes, and construction equipment.
• Rail transportation: In train and subway systems, sleeve bearings are used to support wheels and axles.
• Shipbuilding industry: In the main engine, transmission system, steering gear, and other components of the ship, sleeve bearings can provide reliable support and operation.

What Is The Difference Between A Sleeve Bearing And A Bushing?

Although sleeve bearing and bearing bushing are somewhat similar in structure and function, there are some differences between them:

Sleeve bearing usually refers to cylindrical rolling bearings with a large aspect ratio, which mainly bear radial loads and require a continuous supply of lubricant from an external lubrication system. They are generally used in critical applications carrying larger loads.

The bearing bushing refers to a short cylindrical or annular sliding piece with a small inner diameter. It is mainly used to provide support and positioning of the shaft, and its load-bearing capacity is relatively limited. Bushings are usually made of self-lubricating polymers or metal materials containing solid lubricants, requiring no external lubrication system. They are widely used in various general machinery.

Why Choose Us?

FHD Bearings is a leading manufacturer with over 20 years of expertise, providing unparalleled quality and exceptional service to brand procurement professionals worldwide. Our sleeve bearings undergo rigorous testing to ensure durability and performance. In addition, we have other types of high-quality bearings such as roller bearings, ball bearings, custom bearings, etc.; no matter what your application is, FHD can provide excellent bearings to customers around the world.