LLG Spherical Plain Bearing

LLG Spherical plain bearing is designed to accommodate different builds and kinds of applications to meet the demands of your business needs.

LLG spherical plain bearing is mainly used for railways, constructions, hydraulic structures, power plants, mining, and aggregation processing. We in LLG are producing a lubricated and grease-free rod end of a spherical plain bearing.

Our spherical plain bearing has the characteristics of huge load ability and easy to mount.

Purchasing of LLG Spherical plain bearing offers a heavy-duty load of productivity, highest operational accuracy, and maintenance-free, it also has a long service of life.

Once Spherical plain bearing is installed, because of minimal maintenance, the cost expense is avoided. We in LLG want to benefit the user like operators, also focusing on a wide range of applications is our utmost concern.

We in LLG as the certified and expert provider of spherical plain bearing, are also focused on the international market, to satisfy the increasing demands of our customers.

LLG is also providing products based on international standards. Together with our Engineers and Quality Assurance team, we secure that the quality of our spherical plain bearings that we are releasing in the market has an edge over others. What are you waiting for, Send an Inquiry!

Spherical Plain Bearing-The Ultimate FAQ Guide

As the world is advancing day-by-day, manual labor is replaced by machines to perform various operations. In the current era of modern technology, the request or demand for efficient working of machines has elevated.

Financiers’ main goal is to search for the machines which have high operational power, produces less friction and are more durable. In this modern era, manufacturing of such machines is a great challenge for all.

LLG bearing company is working to add above features in their bearings according to the requirement of their customers. Satisfaction is guaranteed with their bearings.

Let me introduce you spherical plain bearings.

• What Is a Spherical Plain Bearing?

A spherical plain bearing is a kind of bearing which allows angular rotation at a pivoted point. Spherical plain bearing assist a rotating shaft in the hole of the internal hoop which rotates at some angle.

Spherical plain bearing help to align the shaft which undergoes misalignment. Spherical plain bearing is designed in such a way that it can bear extreme radial load and provide steady working of shaft in great speed and force applied. 

Spherical plain bearings include ball bushing cylindrical and lined housing which results in reducing the friction produced. It also provides self-lubrication. 

Spherical plain bearing is also referred as ball bushing. Spherical plain bearing is produced through hardened high quality steel.

Spherical plain bearings can be used in devices moving on a low speed.  

Spherical plain bearings have various advantages:

• Spherical plain bearing has high capacity
• Spherical plain bearing can easily manage misalignment
• Spherical plain bearing housing and shaft design is simple
• Spherical plain bearing is easy to install
• Spherical plain bearing perform well in devices producing low level of friction
• Spherical plain bearing provide produces less noise
• Spherical plain bearing maintenance cost is low
• Use self-lubricating bearings

Spherical plain bearings have numerous series ranges. 

Spherical Plain Bearing

• How Does Spherical Plain Bearing Work?

Spherical plain bearing is marked by having amazing load carrying capability. It is used in bearing arrangement when misalignment between shaft and housing occur and a great amount of load is applied. Spherical plain bearing is non-wear. 

Spherical plain bearing has an internal ring with sphere convex outside top and an external ring with sphere concave inner surface. These are raceways and they slide pass each other.

• What Are the Tips to Assemble Spherical Plain Bearings?

To assemble spherical plain bearings, various ways are adopted like press-fitting, screwing, gluing. When the spherical plain bearings are too much press-fitted, they will result in cracks due to thin walls. 

Here is the list of tips which ensure easily fitting of spherical plain bearings without any crack and broken parts.

Tips to assemble

• Observe the tolerances when installing

Many of the plain bearings show tolerances in their specifications as well as product sheet. This is the tolerance of the plain bearing as well of the housing and rotating shaft. When the bearing is successfully installed then press fit holds it in the hollow space.

The external diameter of the spherical plain bearings is solely based upon moisture and thermal expansion. 

• Use aid for a press fit

The perfect way to install spherical plain bearings is by hand press due to simple design. 

Centering spindles help during fitting but they easily break due to plastic bushes exposure. Place the bushings into the case with chamfer. Chamfer stops the bushing to tilt and keep it straight. 

• Chamfer housing holes

Housing holes having sharp edges play a vital role to strip plain bearings. It does not cause destruction of bushings but in plastic bushings results in clearance. Simple chamfer helps in easy fitting of spherical plain bearing. 

• How Do You Measure Spherical Plain Bearings?

You need a replacement room and don’t know which measurement to take?

It is the right time to find the old room and perform some measurements.

Spherical plain bearing contain marks either in the form of letters or numbers. 

Spherical plain bearing consist of two raceways such as internal raceway or speedway and internal raceway. 

You can measure spherical plain bearing when the internal diameter, external diameter and the width are known. You can represent them in this way:

ID = Internal diameter

OD = External diameter

W = Width

OD x ID x W

Measurement for spherical plain bearing is mostly taken in mm measurement but can be altered into inches as well. To measure spherical plain bearing following steps are required

Steps to measure

• Find the internal diameter by adding the stapes of caliper into the internal hoop of the spherical plain bearing. It must be fitted by borders and must not be tight enough.
• Find the external diameter by putting the spherical plain bearing between the jaws of the caliper to adjust it perfectly nut not tight enough. Now, measure it using a scale or to other outside border. 
• Find the width of the spherical plain bearing by putting it between the jaws of the caliper. Avoid tightening of the spherical plain bearing because it will not give the exact width of bearing. Measure it with the one external border and the other with the aid of scale
• Use a size chart to find the series number.

 Measuring Diameter

Designation System

In this system, there are almost three or five numbers to measure.

• The initial number or letter or the collective form of them point out the type and variant
• The next two numbers recognizes the dimension series. First number shows the width (height) and the other second number point out the dimension. 
• The last two numbers point out the size code of the spherical plain bearing hole. When the size code is simplified with 5, it will give diameter of the hoop hole. 

• What Are Thrust Spherical Plain Bearings?

Thrust spherical plain bearings consist of sphere surface which is on a hollow or a shaft washer. 

Thrust spherical plain bearings are used to bear high axial loads but can also operate when a radial load is applied. When the radial force is applied it must not elevate 50% level of the axial pressure. When the radial load is exceeded, the combination of thrust spherical plain bearings with radial bearings is suggested.  

Thrust spherical plain bearings are constructed in such form that they can bear shock as well as greater thrust pressure. They are mostly used in industrial and automotive applications. 

Spherical plain thrust bearings consist of convex spherical top side on the washer which is of shaft and concave internal housing. The rotating shaft plus housing are primarily manufactured by steel which is mainly grounded. 

The sliding or plain surface of the rotating shaft is made of hard chromium layer furnished with grease (lithium). Thrust spherical plain bearing consist of a cage for the rolling element. Internal and external hoop of the spherical plain bearings are layered with phosphate to prevent from corrosion and reduce the friction. 

 Size ranges are 35mm to 2940mm. Temperature range for thrust spherical plain bearing can be -30⁰C to approximately 80⁰C. 

Thrust Spherical Plain Bearing

• What Is Permissible Operating Temperature Range for Spherical Plain Bearing?

Spherical plain bearing is a bearing which can withstand axial load and a little amount of radial load. Spherical plain bearing is used when a greater force is applied and misalignment occurs. 

The permissible optimum temperature range for spherical plain bearing is -30⁰C to 130⁰C. As the temperature increases, spherical plain bearing cannot bear load applied because it operates well in limited temperature range. 

The spherical plain bearings without sealing have the ability to operate at 200⁰C

• What Are the Specifications of Spherical Plain Bearings?

Spherical plain bearings are bearings which support the rotating shaft in the hole of the internal ring and shows both angular and rotational movement. They can operate well in low speed and greater axial load.

Various vital physical dimensions include:

• Diameter of the bore
• Spherical plain bearing thickness, length when passing the hole (bore)
• Spherical plain bearings are measured in units such as inches, metric sizes, centimeters and millimeters
• In many cases, spherical plain bearing movement is symmetrical around the pivoted point
• Most of the spherical bearings are self-lubricating
• Spherical plain bearings are corrosion resistant 
• Spherical plain bearings have greater axial load bearing capability and radial load performance. 

• How Do Self-Lubricating Spherical Plain Bearings Work?

Self-lubricating bearings are those bearings which can lubricate by their own without need of any outside lubrication. 

These are widely known as maintenance-free bearings. Self-lubricating bearings work by impregnated lubricant within the sliding layers. When self-lubricating spherical plain bearings operate, the grease or a lubricant is spread on the sliding surface and the bearings operate quietly. 

• Does Spherical Plain Bearing Require Maintenance?

There are different types of spherical plain bearings such as:

• Spherical plain bearings which require maintenance. 

• Spherical plain bearings with no maintenance.

 Spherical Plain Bearings which require maintenance

Such bearings which require maintenance are steel-on-steel. They have stiffed sliding contact top surfaces on both internal and external rings. The top side of spherical plain bearings which require maintenance are treated with phosphate and other substances.

Sliding contact surface needs regular re-lubrication to reduce wear and to extend life. Sliding contacts of the spherical plain bearings enable them to bear heavy loads and shocks. A special type of grease lubricant is used in steel-on-steel spherical plain bearings. Properties of grease are:

• High quality grease gives good working even when heavy load is given. 
• It inhibits the chance of rusting
• Increase the service life
• Wide temperature range for operation

Spherical plain bearings have holes and habit in the internal and external ring to allow re-lubrication through shaft as well as housing.

Re-lubrication series rely on magnitude of force, frequency and heights of the swing. When spherical plain bearings are re-lubricated, dynamic load rating is based on film strength of grease (lubricant).

•  How Does Maintenance-Free (Lubrication-Free) Spherical Bearings Are Used?

Spherical plain bearings which need no maintenance are the bearings which require no lubrication. 

The spherical plain bearings which are maintenance-free consist of external hoop made of stainless steel, chromium steel and carbon steel. 

Carbon steel hoop of spherical plain bearings having external hoop is pressurized or fitted around the internal ring and experience radial break.

Spherical plain bearings having copper mixture with internal hoop is given solid grease on the contact area. 

Maintenance Free Spherical Plain Bearing

Steel ⁄ PTFE bronze and Steel ⁄ PTFE fabric 

In operation of Steel ⁄ PTFE bronze and steel ⁄PTFE fabric sliding contact surface, PTFE is transmitted from the rough sliding contact top side of the external ring to the stiffed chromium covered metal surface of internal hoop.

 Whenever grease or a lubricant is added manually from the outside on the sliding contact area, this will result in self-lubricant disturbance and life rate of the spherical plain bearing is decreased to a great extent. So, an external lubricant should not be given. 

Steel/Bronze Spherical Plain Bearing

Steel ⁄ PTFE FRP 

Spherical plain bearings requiring this kind of maintenance are lubrication free and work without grease. This type of lubrication expands the bearing life by two. The internal ring of the rotating shaft and radial bearing is furnished by grease made of lithium. 

• What Are the Applications of Spherical Plain Bearing?

Spherical plain bearings are used in various industrial machines and equipments. These are mentioned below:

• Aerospace and defense
• Mining machines
• Engines
• Car suspensions
• Drive shafts
• Sewing machines
• Robotics
• Bridge building
• Power generating devices
• Wind turbines
• Roof designs
• Railways manufacturing
• Agriculture
• Heavy machines
• Apartment blocks

How Many Types of Spherical Plain Bearings Are There?

These plain spherical bearings are made of stiffed steel and are present in various sliding contact surfaces. Spherical plain bearings can be constructed in the form of seal or without seal. 

Types of spherical plain bearing

• Thrust or Angular contact spherical plain bearing

In this kind, sliding surface is in the angular form and also makes an angle with the centralized point. These spherical plain bearings have the power to bear radial as well as axial loads in one direction. They are best used in devices having low speed and greater thrust load. 

• Radial plain spherical bearing

Radial spherical plain bearings are utilized in such bearings which have the power to take higher radial load and less axial pressure. These bearings are found in the sealed form which protects from contamination and prevent the leakage of the grease added. 

Radial spherical bearings are best applicable in equipments of low speed such as steering axles and cylinders (hydraulic). Radial spherical plain bearings can align themselves in any direction. 

Radial Spherical Plain Bearing

• Radial spherical plain bearings which are self-lubricated

This type of bearing can operate by itself on limited speed and greater radial pressure, when a lubricant is required it performs quietly. There is no need to add a lubricant.

This kind of spherical bearing is lubrication-free and supports such system in shaft and housing. Its sliding surface areas are metal to PTFE. 

• Self-lubricating angular contact spherical plain bearing

This kind of spherical plain bearing is used in application which moves on low speed and greater thrust load is applied on them. The main feature is that it can operate quietly and have the capability to align. 

• Radial formed spherical plain bearing

This kind of spherical plain bearing is used in low speed and has high vibration. It has long bearing life. Spherical surface of internal hoop is layered by chrome. 

How Many Groups Spherical Plain Bearings Can Be Divided?

Spherical plain bearings can be divided into major two groups:

• Spherical plain bearings requiring maintenance
• Maintenance-free spherical plain bearings

Maintenance requiring spherical plain bearings consists of stiffed sliding surface on internal and external ring. The surface is subjected with molybdenum di-sulphide and phosphate. Bearings having such sliding surfaces need regular maintenance. Such sliding surface makes them resistant to vibration, noise and shocks. 

Spherical plain bearings which are maintenance-free have three types of sliding surfaces such as steel-on-PTFE, steel-on-copper alloy and steel-on-PTFE fabric. These bearings can work without maintenance. They are mostly used in equipments or machines where long life is required. 

What Are CIP Spherical Plain Bearings?

CIP spherical plain bearings are mixture of self-aligning and lubricating spherical plain bearings in which the races are replaced by steel-on-steel and tiny rolling elements. When the metal is replaced such as tiny rolling ball or a speedway with the CIP composite, you can still operate such bearings by giving no lubrication. 

CIP composite substance aid in dividing load and decrease the noise produced which results in failure of tiny rolling bearings. 

CIP composites spherical plain bearings are used in heavy machines working in industries, agriculture, oil and gasoline, wind energy and handling of substances. 

Spherical race is the widely used element in applications carrying greater load. The internal top side or surface is spherical in shape which helps in fitting over the metal ball in various forms like single-split, double-split and in window cut form. This results in un-troubled mounting or installation. 

Internal spherical rolling elements constructed from CIP composites operate in applications on which light pressure is applied. Such style offers a great amount of maintenance. 

CIP spherical plain bearings have an external spherical race diameter of 16 inches and 14 inches of ball. 

CIP Spherical Plain Bearing

What Are the Benefits of Using CIP Spherical Plain Bearings?

CIP plain spherical bearings are widely used in various industrial machines due to certain features which are following:

• CIP spherical plain bearings are self-lubricating because a solid lubricant is spread all around the material to avoid any external lubricant.
• CIP spherical plain bearings lower the friction produced which causes the wear problem
• These bearings are made for heavy weight and low speed bearing equipments
• CIP spherical bearings do not lose their chemical composition when submerged in fresh or mineral solvent

• CIP spherical  bearings are easy to handle and install

Examples

Fire truck ladders, dump truck body lift, hydraulic cylinders.

What Are the Similarities and Differences between a Plain Spherical Bearing and a Roller Bearing?

Due to the standard form and size of spherical plain bearing which comes in various industrial machines and equipments, spherical roller bearing is also in competition with spherical plain bearing. The major similarities and differences between the two are stated below:

Spherical plain bearing

As the name indicates, spherical plain bearing has smooth and solid planes or surfaces that move in a relative motion. The ring rotates across the central point. This bearing is labeled as high operational bearing. Spherical plain bearing are durable and maintaining cost is less. It is designed to bear heavy force. 

Spherical plain bearing use a soft bronze roller bearing and a shiny, furnished metal shaft. But the negative side is that full exposure of sliding planes with each other causes high vibration and friction.

Spherical plain bearing size increases when then the load applied on it becomes greater.  

Spherical roller bearing

Spherical roller bearing is a mixture of plain and spherical ball bearing. It can be easily adjusted than that of plain spherical bearing. It is smaller in size when the load increases. 

Differences

• Spherical plain bearing need a high start up torque than that spherical roller bearing
• Spherical plain bearing in thrust load requires special manufacturing design which is cost effective. 
• Spherical plain bearing is used in low speed while spherical roller bearing can withstand greater speed. 
• When the power supply is high then spherical rolling bearing wear out quickly and cannot perform well but spherical plain bearing works best.  In normal load, plain spherical bearing has greater wear than spherical roller bearing due to direct friction between shaft and ring. 
• Plain spherical bearing is used for linear and rotational motion but spherical rolling bearing supports rolling movement. 
• Spherical plain bearing has no tiny rolling element but spherical rolling bearing has. 

Spherical Roller Bearing

What Are Angular Contact Spherical Plain Bearings?

Spherical Angular contact bearings are those bearings which have the ability to take both radial and thrust loads equally. Such bearings bear thrust load which is unidirectional.  The sliding plane make an angle with the central point. When the spheres intersect each other then clearance free spherical plain bearing is attained. 

Angular contact spherical plain bearing has two types based on the plane contact

• Metal-on-metal angular contact spherical plain bearing
• Maintenance-free angular contact spherical plain bearing

Angular Contact Spherical Plain Bearing

Applications

• Agricultural machines
• Mining tools

How to Install a Spherical Plain Bearing?

After the removal of old bearing, the installation of a new bearing is carried by keeping in mind factors like size, structure and the fitting parts of spherical plain bearing. 

You need to apply a pressure on the tight-fitting rings of the spherical plain bearing. Keep in mind that pressure applied must not transfer to the rolling elements otherwise it will cause marks and damage of spherical plain bearings. 

Avoid applying pressure on the cages, seals and other parts of the bearing because they can quickly deform. 

Spherical plain bearing external ring has a loose fit with the housing. 

When installing a spherical plain bearing, the pivot point of the outer hole must coincide with the shaft. With a press missing, bearings can e installed with a hammer.  

The outer diameter of mounting sleeve must be smaller than hole of housing diameter. 

When the external ring of spherical plain bearing and housing hole is fitted enough, housing can be heated and installed easily into the spherical plain bearing. 

How Do I Identify a Spherical Plain Bearing?

Every bearing consist of an invoice number which is imprinted on it. It is easy to identify the bearings with the help of it. 

If this is not possible then you measure it by measuring bore’s internal diameter, the external diameter and the width. 

Other way to measure the bearing is by observing material and other features such as tolerance and radial pitch. 

For more information, you can contact at our LLG bearing website. 

How to Calculate Spherical Bearing Rating Life?

Rating life for such bearings is the bearing working with 90% reliability. This is referred as the total time which bearings will complete before fatigue failure. The formula to determine bearing life is:

L10=CPe ×10*6 /60×N

C= Dynamic capacity

P= Equivalent bearing load

N= Rotating speed

e= Coefficient for spherical plain bearing

For more details and any query, LLG technical experts are available to guide you.