BEARING LUBRICATION TYPES

 

Lubricants help bearings perform their core function: Reducing friction.

It’s necessary that we pay attention to the purposes of different types of grease and their functions, and how we should lubricate bearings.

Ideally, there should be just a thin film of grease between the surfaces where friction is to be minimized. Additionally, this film of grease should facilitate heat dissipation to prevent overheating of bearings, and protect the parts from moisture, corrosion and ingress of contaminants.

A good lubricant has the following characteristics:

- Consistently viscous over a broad temperature range
- Structurally stable to improve longevity
- Non-corrosive to covered components

1.Oil Based Lubricants:
Pros:
Reduced torque
Higher speeds achievable

Cons:
- Subject to evaporation, hence service life may be lesser than grease

Small bearings are typically lubricated only once in their lifetimes, but more heavy duty bearings require re-lubrication systems installed onto them for maintaining uniform lubrication levels and standards.

Selection Criteria:
Viscosity, Evaporation Rate and Temperature Range

SS - Oil Lubrication

 

 

2.Grease Based Lubricants:
Pros:
Additive oils and substances can improve bearing performance through anti-corrosion components and fortifiers
Minimised tendency to evaporation due to semi-solidity

Cons:
- Lower tolerance to high speeds

Selection Criteria:
Stiffness Level, Base Oil Viscosity and Temperature Range

Most Commonly Used:
NLGI Type 2 for bearings with rolling elements

Check out our range of Greases here!

 

KYK Grease
3. Solid Lubricants:
Pros:
Can handle extreme situations where oil & grease cannot perform – Eg. Extreme temperatures, vacuums and radiation zones.
Minimised tendency to evaporation due to semi-solidity

Cons:
- Highly specialised application lubricants may be difficult to procure

Coating Materials:
Molybdenum Disulfide (MoS2), Graphite, Gold, Silver and Polytetrafluoroethylene (PTFE)

 

SS - Solid Lubrication

 

Should you ever need help in choosing the right grease, feel free to contact us and one of our engineers will help you make the right choice!

Team Eurasia!

 

Posted in Uncategorized | Tagged , , , , , | Leave a comment

Three Simple Ways to Correctly Mount a Bearing

 

Theoretically, a bearing’s life can exceed that of the machine in which it’s installed. But in reality, about 1/6th of premature bearing failures occur on account of poor fitting due to – Forceful Installation – Not using the correct fitting tools – Unawareness of the importance of correctly mounting bearings

IDEAL MOUNTING TECHNIQUES:

 

1. Mechanical mounting: Using a fitting tool, an impact ring and a sleeve against the bearing’s mountable ring to install the bearing ensures that the bearing fits firmly onto the shaft. The right mix of the impact ring and sleeve effectively distributes the mounting force across the ring of the bearing, reducing the risk of damage to the bearing’s raceways and rolling elements.

Rule of Thumb: – The bearings should ideally be positioned perpendicularly to the shaft, which should be slightly lubricated with a thin oil film.

 

2. Heat mounting: Using a bearing heater, which uniformly distributes heat across the bearing, a slight expansion in girth can be achieved to smoothly install the bearing. The bearing manufacturer specifies the heating limits, as they largely vary with the absence or presence of metal shields, lubricants and other design differences, which may react differently upon being subjected to heat as compared to the bearing. Typically, a temperature difference of 83ºC (150ºF) is sufficient to achieve the necessary expansion for smooth mounting, without causing irreversible changes in the metallurgy, brittleness and dimensions of the bearing and its accessories.

Rules of Thumb: -Don’t heat bearings to more than 125ºC (257ºF) unless otherwise stated. – Induction heaters for bearings are most effective and less hazardous than other lesser-recommended methods such as exposure to flames, hot oil baths and hot plates.

 

Words of Caution: The electric current of induction heaters magnetise the bearing, requiring immediate demagnetization to avoid metal particles getting attracted towards the bearing resulting in possible contamination, hence premature failure. It is recommended to opt for induction heaters which automatically demagnetize the bearings after the heating process.

3. Hydraulic Mounting:
This is the recommended method for mounting of large bearings (with interference fits).
Perfect mounting can be achieved through oil injection, usage of specialised hydraulic nut to develop the sufficient hydraulic pressure for smooth mounting along with a hydraulic pump and a pressure gauge.
You could save your machine and money simply by educating your users about proper mounting!

 

.

Posted in Uncategorized | Tagged , , | Leave a comment