LLG Journal Bearings

LLG journal bearings are made to support rotating shafts and are usually used in various operations like power trains and engines. LLG journal bearings are also known as plain bearings or sliding bearings.

LLG journal bearings have the simplest structure without rolling elements. These bearings support the rotating operations at high speed.

Journal bearings are usually used in pumps, power trains, engines, marine applications, Etc.

LLG journal bearing advantages are that they run quieter than other bearings, prevent friction in the machinery’s moving parts, and less prone to damage or fatigue.

LLG offers a wide range of journal bearings, OEM with premium quality, and a fast delivery process.

We use advanced machinery and technology to provide the quality of the five-star bearing.

For inquiries, please get in touch with us.

Journal Bearing – The Ultimate FAQ Guide

Supporting the rotating shaft of your equipment during its operation is a challenging task, no doubt!

Not only this, but supporting both crankshaft and camshaft is another challenging task.

But don’t worry; you can use journal bearings to make your tasks easy.

The following FAQ guide contains some helpful questions about the journal bearing, its usage, and its explanation.

Let’s get started!

• What Is a Journal Bearing?

Journal Bearing is a particular rotating bearing with an integrated shaft or journal that keeps on spinning freely.

During the rotation, this bearing plays the leading role in supporting the metal sleeve or shell.

In this kind of bearing, there are no prominent rolling elements. Moreover, they have a comprehensive yet straightforward design with a plain or straight configuration.

The overall configuration of the Journal Bearing comes with a flange that is used to accommodate the combination of axial and radial loads.

Lastly, Journal Bearings are most commonly used in the water-resistant and high-temperature series.

Journal Bearings

• How Does Journal Bearing Work?

Journal bearings work by rotating the integrated shaft inside the loose-fitting bearing shell.

The bearing shell is mostly porous, containing the bearing material in a unique sequence.

In addition to this, the journal bearings support the rotating machinery at high speed, such as turbines or compressors.

Besides supporting the shaft, Journal Bearings also play an essential part in enhancing the quality of rotating machinery.

Working of Journal Bearing

• What Is a Journal Bearing Used For?

Journal Bearings are used for:

• Supporting the shaft and the bearing shells
• Supporting the crankshaft
• Holding the camshaft
• Giving the moving machine an improved rotational speed
• Enhancing the rotation’s quality in the equipment

• What Are the Types of Journal Bearing?

The two main types of Journal Bearings are:

• Sliding or Plain Surface Journal Bearings
• Rolling Element Journal Bearing (Ball Bearings)

Some other common types of Journal Bearings are listed as under:

• Sleeve Journal Bearing
• Plain Journal Bearing
• Shell Journal Bearing
• Babbitt Journal Bearing

Types of Journal Bearing

• What Is the Purpose of Journal Bearing?

Journal Bearings are more precisely abbreviated as hydrodynamic bearings.

The primary purpose of Journal Bearings is to support the rotary machine’s rotating shaft. In addition to this, Journal Bearings are also purposed to be used in several subsystems of the rotational machinery.

They are used in engines and power trains for supporting or enhancing rotational movement.

• Why Is It Called Journal Bearing?

Journal Bearings are called so because the shaft portion where these bearings are installed is known as a journal.

Moreover, the journal bearings operate by making the most of the pressure wedge caused by the fluid of the rotating shaft and the bearing.

Not only this, but Journal Bearings is also usually hardened for resisting the wear and tear in the rotating machinery.

Name of Journal Bearing

• What Is a Better Option Journal Or Ball Bearing Turbo?

No doubt Journal Bearings are known to improve the rotational activity of the moving machinery, but overall, ball bearing turbo is considered a better option than the former.

Ball-bearing turbo can reduce the oil flow in the engines and demand an adequate amount of lubrication. Thus, the reduced oil flow in the ball-bearing turbo will also decrease the chances of oil leakage.

Besides this, ball bearings play a vital role in decreasing the damping, thereby enhancing the rotor dynamics and durability of the machinery.

• What Is the Difference Between Journal Bearing and Roller Bearing?

The primary difference between Journal Bearing and Roller bearing lies in the extent of the radial space these bearings need for their operation.

Journal Bearings require minimal radial space, but roller bearings need more axial length for their operation.

In addition, the Journal Bearings come with a specialty to overcome or manage the shock and overload, whereas the roller bearings miss this property.

Journal Bearings are less prone to fatigue even after recurrent usage, but the roller bearings can easily get damaged by a sight load.

Difference between Journal Bearing and Roller Bearing

• What Is the Difference Between Journal Bearing and Thrust Bearing?

The significant difference between the Journal Bearing and Thrust Bearing is related to their working in integration with the shaft.

Journal Bearings are commonly used to allow the shaft to rotate while holding the shaft in a horizontal position.

But in contrast to the Journal Bearing, a thrust bearing prevents the movement of the shaft by moving it along the length of rotation.

Moreover, it can also be used to support the crankshaft or the camshaft, but the thrust bearing applies force for separating the plates in a mechanical clutch.

Difference between Journal Bearing and Thrust Bearing

• How Can You Find Journal Bearing Clearance?

Clearance is one of the vital specifications in the working of the Journal Bearing.

However, you can measure the clearance of the Journal Bearings by the housing’s contour in which the specific bearing is installed.

The other way to determine the clearance is to calculate the crush or interference between the support housing and the Journal Bearing shell.

Clearance of Journal Bearing

• hat Are the Advantages of Journal Bearing?

Some of the potential advantages of Journal Bearings are listed as under:

• They help to manage the shock and overload
• These bearings improve the rotational movement of the machinery
• They run quieter than other bearings
• They prevent the wear and tear in the machinery’s moving parts
• These bearings are less prone to damage or fatigue

• What Are the Disadvantages of Journal Bearing?

The significant disadvantages of using Journal Bearing are given in the list below:

• Journal bearings require ample supply of oil to lubricate frequently
• They are suitable only for the low temperature operating equipment
• Journal Bearing work best for low rotational speeds
• These bearings offer high initial resistance
• The running resistance is not as significant as the initial resistance
• The operation of the Journal Bearing slowly builds up the layers of lubricants

• How to Install Journal Bearing?

The steps for the installation of the Journal Bearing are listed as under:

• Before carrying out the installation of the Journal Bearing, make sure to check its clearance
• Once you get the confirmation of the clearance, the Journal Bearing is all set to assemble
• The installation of the lower ring raceways of the Journal Bearing is installed before the outer ring raceways
• Once the inner ring raceways are correctly placed, the person installs the outer rings of the Journal Bearing
• After placing the rings on each other and confirming their alignment, the nuts and bolts are put together
• Tighten all the nuts and bolts with the help of nuts and bolts 
• Now install the thrust bearing on the shaft
• After the installation of the bearing on the shaft, place the housing of the Journal Bearing

• How to Replace Journal Bearing?

The replacement of the Journal Bearing is carried out in the following steps:

• To start if off, remove the bolts from the top half of the bearing’s housing
• The next step is the removal of the guide pins that are used to align the two halves of the housings in the Journal Bearing
• When all the bolts and guide pins are removed, it’s time to remove the top half of the housing and set it aside
• Now remove the bolts of the Journal Bearing that holds them together
• Take the upper part of the Journal Bearing’s shell from the shaft
• Now slightly raise the shaft and remove the Journal Bearing’s lower part
• When the shaft is raised, make sure to remove the lower bearing very carefully
• After removing both the upper and the lower parts of the Journal Bearing, inspect the shaft for the presence of high spot scoring and discoloration
• Inspect the bearing, particularly for high scoring spots
• In case of corrosion and wear or tear, replace the bearing with another one

• How Can I Inspect a Journal Bearing?

The inspection of the Journal Bearing comprises of the following points:

• Make sure to have a profound knowledge of the bearing reuse and replacement before carrying out its inspection
• Check the accuracy of the dimensions in the Journal Bearings
• Ensure to check the bearing dimensions during its operation
• Take account of the internal clearance of the Journal Bearing
• Check the rolling contact surfaces in the Journal Bearing
• Make sure that all the cages and seals are correctly assembled or not

• What are the Causes for the Failure of Journal Bearing?

Some of the potential causes that are responsible for the failure of Journal Bearing are listed as under:

• Inefficient lubrication 

The most common cause behind the failure of 80% of Journal Bearings is improper or faulty lubrication. This factor also included the choice of wrong or incompatible lubrication oil, the excessive temperature of the bearing during lubrication, or extra lubricant degradation.

• Improper Mounting of the Bearing 

Another main reason for the Journal Bearing’s failure is the improper mounting. If the bearing is improperly mounted on the shaft with a press-fit wrongly assembled on the rotating ring, malfunctioning is confirmed.

• False Brinelling of the Bearing Raceways 

Idling the equipment during the ball’s rapid movement in the raceways can cause the bearing to wear away. The inefficiency of the superior lubrication also causes the inability of the beaing to return to the initial spot.

• Corrosion 

Another common cause of the failure in the Journal Bearings is excessive corrosion. It can be due to moisture, acidic environment, low-quality lubricant or grease, or extreme temperature during the bearing’s operation.

• The fluting of the bearing 

Electrical damage, also called fluting, can cause the failure of the Journal Bearing. Significant fluting causes are regarded as low currents or direct currents in the electric supply.

Failure of Journal Bearing

• How Can I Prevent the Failure of Journal Bearing?

You can prevent the failure of the Journal Bearing by acting on the following tips:

• Make sure to choose the most compatible lubricant for the Journal Bearing
• Filter the grease or lubricant for reducing the chances of contaminants in the Journal Bearing
• When mounting the Journal Bearing on the shaft, follow all the instructions given by the manufacturer
• Don’t compromise on the misalignment of the Journal Bearing. You can do this by inspecting the working of shafts and housings of bearing seats
• Minimize the movement of the balls by eliminating or absorbing the external vibration that can cause the Brinelling of Journal Bearing
• Seal the bearings for protecting them from the hostile environments responsible for the corrosion of Journal Bearings
• Use insulated bearings for preventing the electrical currents

• What Materials Are Used in the Construction of Journal Bearing?

Following materials are used in the construction of the Journal Bearing:

• Polymer of Molybdenum
• Graphite
• PTFE or Nylon
• Chrome Steel

Materials of Journal Bearing

• What is the Manufacturing Process of Journal Bearing?

The manufacturing process of the Journal Bearing comprises of the given steps:

• The first step in the construction of the Journal Bearing is the selection of the suitable materials
• The majority of the manufacturers, including LLG Bearing, prefer to use chrome steel and molybdenum to make the Journal Bearings
• The manufacturing process begins with some automatic machines, which are similar to lathes or screw machines
• These machines are used to make the rings of the Journal Bearing
• The stamp machine pastes the bearing number and manufacturer’s information on the outer ring
• Now both the rings are heated to about 1565 degrees to harden them into a particular shape
• After hardening, the rings are then passed for grinding with the use of special grinding machines
• The primary reason for grinding the rings of Journal Bearing is to achieve the desired width, bored of the inner and outer rings, and for making the proper radius and race location of the rings
• The last step in the construction of the Journal Bearings is the honing of the bearing’s races by maintaining a suitable surface and geometry

• What Is the Optimal Temperature for the Operation of Journal Bearing?

The optimal temperature for the proper operation of the Journal Bearing is about 100 degrees Centigrade or 210 degrees Fahrenheit.

The working of the Journal Bearing is restricted to low weight and low-temperature conditions since it can decrease the viscosity of the bearing’s lubricant, thereby increasing the chances of failure.

• What Are the Parts of Journal Bearing?

The primary parts of the Journal Bearings are listed as under:

• Oil Inlet
• The housing of the bearing
• Clearance
• Journal or Shaft
• Split Type
• Bearing Liner
• Compressors
• Crankshafts
• Rotors
• Thrust bearings

Parts of Journal Bearing

• How to Remove Journal Bearing?

You can remove the Journal Bearing by the following steps:

• Before removing the Journal Bearing, make sure to remove the dirt and debris from the housing of the bearing
• For removing the Journal Bearing, look for the match marks since they will significantly help you to disassemble the bearing
• Thoroughly inspect the housings of the bearing for fractures and indications of upcoming problems
• Unbolt the bearing cap and take a brief account of the bearing surfaces
• Clean the shaft from the contaminants that can disrupt the lubricant film
• Loosen all the nuts and bolts for removing the upper and lower rings of the Journal Bearings

• Why Are Copper-Based Alloys Used in the Construction of the Journal Bearing?

The majority of the Journal Bearings are constructed using the highest quality of copper-based alloys, including graphite and molybdenum because they can provide a long-lasting, lubricating film.

The large group of materials in these alloys proves as the best additives in the Journal Bearings.

• Why Do We use Split Journal Bearing?

We primarily use split Journal Bearings to allow the shaft to support the lower section of the Journal Bearings.

It can be done quickly when the top or upper section of the Journal Bearing is removed, thereby making it simple and accessible for the inspector to remove and check the bearing’s efficiency.

Split Journal Bearing

• Why Is It Important to Determine the Clearance of the Journal Bearing?

It is essential to take a brief account of the Journal Bearing clearance since this property is used to assemble the shaft with the bearing.

Not only this, but the clearance factor in the Journal Bearing also creates the demanded gap, which is required by the lubricants.

Some other purposes of determining the Journal Bearing clearance include reducing the thermal expansion of the Journal Bearing, minimizing the misalignment of axial load, and removing the deflection problems during the operation of Journal Bearing.

• Where to Buy Journal Bearing?

There are many worthy options of manufacturers in different countries around the globe, but China seems like the most preferred option to go with.

The primary reason for selecting China as the center of buying Journal Bearings is the availability of many efficient manufacturers.

LLG Bearing is also one of those Chinese manufacturers who play the leading role to satisfy the customers with the highest quality of Journal Bearings.

• What Is Journal Bearing Turbo?

The Journal Bearing Turbo is defined as a compact single sleeve system available with a set of angular contact bearings or one of its ends.

Other than this, the original set of bearings comes with a group of journal bearing and thrust bearings on its adjacent sides.

Journal Bearing Turbo

• How to Rebuild Journal Bearing Turbo?

You can rebuild the Journal Bearing Turbo in the following steps:

• Make sure to inspect the Journal Bearing Turbocharger for damages to avoid any damage
• Inspect the thrust collar and the working of the thrust bearing
• After inspection, in the collar carefully remove the piston ring
• Place the bearing’s compressor wheel and thrust collar on the shaft and tighten all of their nuts and bolts
• Use a machine lightly to illuminate the heavy spots on the bearing that demand some grinding
• Mark an index point at the compressor wheel and the shaft of the Journal Bearing
• Now you’ll be able to assemble the wheel according to its arrangement
• Make sure about the proper positions of the piston ring and thrust collars
• This will help to fill the turbo with oil during the operation
• Once you have maintained the correct position of the thrust collar and the piston ring, it’s time to install the back-plate
• Now make sure to properly install the turbine piston on the top of the hub area
• After this, with the help of bearings, install the shaft into the housing
• Tight the turbine wheel with the help of a vice
• Install the compressor wheel and insert some oil into it while holding the unit with one hand
• Slightly push the compressor wheel in the downward direction by filling up the oil in it
• Ensure the installation of the back plate’s O-ring

• What Are Hydrodynamic Journal Bearing?

Hydrodynamic Journal Bearing can be defined as the journal bearing that is lubricated with the help of hydrodynamic lubrication.

This bearing has a separated surface from that of the journal bearing’s surface with the help of a lubricating film.

The rotation of the Journal Bearings mainly creates this lubricating film.

Hydrodynamic Journal Bearing

• What Are the Qualities of a Good Journal Bearing?

Some of the qualities of a suitable Journal Bearing are listed as under:

• Easy lubrication
• Perfect clearance ratio
• Proper functioning of the length/diameter ratio
• Appropriate eccentric ratio

• What Are the Signs of the Failure of Journal Bearing?

The common signs of the failure of Journal Bearing include:

• Increased vibration than regular operation
• Sintered bearings
• Excessive wear and tear in the bearing
• Enhanced oil whirl in the Journal Bearing
• Preloading in the bearing
• Touch Rub

• Can I Grease the Journal Bearing?

Yes, you can lubricate the Journal Bearings by using the highest quality of greases. The primary reason for greasing the Journal Bearing is to cool down the bearing’s operating temperature, adjusting the high loads, maintaining the low speed and proper rotation of the rings.

Grease the Journal Bearing

• What are the Best Greases for Journal Bearing?

Some of the top-notch greases for lubricating the Journal Bearing include:

• Lithium soap
• Lithium Complex
• NLGI Grade # 2 greases