Journal Bearing
Journal Bearing
Journal Bearing
1)
JOURNAL / FRICTIONAL/ SLIDING CONTACT / PLAIN BEARING. THRUST BEARING. ROLLING BEARINGS:3a) BALL BEARING. 3b) ROLLER BEARING.
2) 3)
SINGLE
ROW DEEP GROOVE BALL BEARING. ROW DEEP GROOVE BALL BEARING. CONTACT BALL BEARING.
DOUBLE
CYLINDRICAL NEEDLE
ROLLER BEARING.
SPHERICAL TAPERED
ROLLER BEARING.
The
sliding contact bearing in which the sliding action is along the circumference of a circle or an arc of a circle and carrying radial loads is known as journal bearing. It is a short shaft (or) the portion of the shaft which is there in bearing is known as journal.
JOURNAL:
BASED ON ANGLE OF CONTACT: Full journal bearing(angle =360). Partial journal bearing(angle <180). Fitted journal bearing(angle <180 & R=r). BASED ON L/D (SLENDERNESS) RATIO: LONG BEARING (IF L/D > 1). SHORT BEARING (IF L/D < 1)). SQUARE BEARING (IF L/D = 1).
JOURNAL IS SLIDING ON THE LUBRICANT BETWEEN THE JOURNAL AND THE BEARING.SO IT IS KNOWN AS SLIDING CONTACT BEARING.
THERE IS A FRICTION BETWEEN JOURNAL & LUBRICANT, LUBRICANT & BEARING. THEREFORE IT IS KNOWN AS FRICTION BEARING.
PERFORMANCE OF JOURNAL BEARING MOSTLY DEPENDS UPON TYPE OF LUBRICATION.
HYDRODYNAMIC / THICK FILM LUBRICATION:- In this type of lubrication the two metallic surfaces are completely separated by a thick film of lubricant. THIN FILM / BOUNDARY LUBRICATION:In this type of lubrication the two metallic surfaces are separated by a few thin layers of lubricant. EXTREME BOUNDARY LUBRICATION:In this type of lubrication metal to metal contact exists.
Let
R=Radius of the bearing r= Radius of the journal e =eccentricity between journal and bearings radius. h= min oil film thickness Then h= R-(r + e).
It
is 100% reliable . Life is infinite. It is a vibration free during loading and unloading. In this bearings lubricant act as a damper. Very heavy loads can be applied.
It
takes more axial space. It takes only radial loads. It cannot run at low speeds. It requires lot of maintenance. It cannot take multi loads i.e. radial and axial loads.
In In
Machine