What is the main advantage of hydrodynamic bearing over roller bearing?

(a) Easy to assemble [IES-2005]

(b) Relatively low price

(c) Superior load carrying capacity at higher speeds

(d) Less frictional resistance

1 Answer

Answer :

(c) Superior load carrying capacity at higher speeds

Related questions

Description : Match List I with List II and select the : [IES-2002] List I (Bearings) List II (Load type) A. Hydrodynamic Journal bearing 1. High radial and thrust load combined B. Rectangular Hydrostatic bearing 2. Radial load only C. Taper Roller ... (a) 2 3 1 4 (b) 4 1 3 2 (c) 2 1 3 4 (d) 4 3 1 2

Last Answer : (a) 2 3 1 4

Description : Which one of the following is correct? [IES-2008] A hydrodynamic slider bearing develops load bearing capacity mainly because of- (a) Slider velocity (b) wedge shaped oil film (c) Oil compressibility (d) oil viscosity

Last Answer : (b) wedge shaped oil film

Description : The most suitable bearing for carrying very heavy loads with slow speed is (a) Hydrodynamic bearing (b) ball bearing [IAS 1994] (c) Roller bearing (d) hydrostatic bearing

Last Answer : (d) hydrostatic bearing

Description : Sommerfeld number is (A) Similar to bearing characteristic number (B) Similar to Reynold’s number (C) Dimensionless parameter that contains all the design parameters (D) Used to find out dynamic load carrying capacity of the hydrodynamic bearing

Last Answer : (C) Dimensionless parameter that contains all the design parameters

Description : The bearing characteristic number in a hydrodynamic bearing depends on- (a) Length, width and load (b) length, width and speed. [IES-1996] (c) Viscosity, speed and load (d) viscosity, speed and bearing pressure.

Last Answer : (d) viscosity, speed and bearing pressure.

Description : A journal bearing with hydrodynamic lubrication is running steadily with a certain amount of minimum film thickness. When the load and speed are doubled, how does the minimum film thickness vary? [IES-2008 ... Gets reduced to one-fourth of original value (d) Gets reduced to half of original value

Last Answer : (a) Remains unchanged

Description : Assertion (A): In steady rotating condition the journal inside a hydrodynamic journal bearing remains floating on the oil film. [IES-2008] Reason (R): The hydrodynamic pressure developed in steady rotating conditions in journal ... A (c) A is true but R is false (d) A is false but R is true

Last Answer : (a) Both A and R are true and R is the correct explanation of A

Description : Petroff’s equation is used to find out (A) Load carrying capacity of the bearing (B) Frictional losses in the bearing (C) Unit bearing pressure on the bearing (D) Pressure distribution around the periphery of the journal

Last Answer : (B) Frictional losses in the bearing

Description : Satisfactory hydrodynamic film in a journal bearing is formed when (a) Journal speed is low; unit pressure on the bearing is high and viscosity of lubricant used is low [IES-2006] ... journal speed, unit pressure on bearing and lubricant viscosity exists resulting in low coefficient of friction

Last Answer : (c) Journal speed is high; unit pressure on the bearing is high and viscosity of lubricant used is high

Description : Consider the following statements: [IES 2007] For a journal rotating in a bearing under film lubrication conditions, the frictional resistance is- 1. Proportional to the area of contact 2. Proportional to the viscosity of lubricant 3. ... 4 (b) 1 and 4 only (c) 2, 3 and 4 only (d) 2 and 3 only

Last Answer : (a) 1, 2, 3 and 4

Description : Match List-I (Type of Anti-friction bearing) with List-II (Specific Use) and select the using the code given below the Lists: [IES-2006] List-I List -II A. Self-aligning ball bearing 1. For pure axial load B. Taper roller bearing 2. For ... C D (a) 2 1 3 4 (b) 3 4 2 1 (c) 2 4 3 1 (d) 3 1 2 4

Last Answer : (c) 2 4 3 1

Description : Assertion (A): Hydrostatic lubrication is more advantageous when compared to hydrodynamic lubrication during starting and stopping the journal in its bearing. Reason (R): In hydrodynamic lubrication, the fluid film pressure is ... (c) A is true but R is false (d) A is false but R is true

Last Answer : (b) Both A and R are individually true but R is not the correct explanation of A

Description : Increase in values of which of the following results in an increase of the coefficient of friction in a hydrodynamic bearing? [IES 2007] 1. Viscosity of the oil. 2. Clearance between shaft and bearing. 3. Shaft speed. Select the ... 1 and 2 only (b) 1 and 3 only (c) 2 and 3 only (d) 1, 2 and 3

Last Answer : (b) 1 and 3 only

Description : In an oil-lubricated journal bearing, coefficient of friction between the journal and the bearing. [IES-1995] (a) Remains constant at all speeds. (b) is minimum at zero speed and increases ... speed. (d) becomes minimum at an optimum speed and then increases with further increase in speed.

Last Answer : (d) becomes minimum at an optimum speed and then increases with further increase in speed.

Description : Which of the following are included in the finishing operations for porous bearing? [IES-2005] 1. Infiltration 2.Sizing 3.Heat treatment 4.Coining Select the using the code given below: (a) 1 and 2 (b) 2 and 3 (c) 2 and 4 (d) 1 and 4

Last Answer : (a) 1 and 2

Description : Cylindrical roller bearing has a lower load capacity as compared to deep groove ball bearing. (a) True (b) False

Last Answer : (b) False

Description : In sliding contact bearings, a positive pressure can be built up and a load supported by a fluid only by the use of a: [IES-2005] (a) Diverging film (b) Converging-diverging film (c) Converging film (d) Flat film

Last Answer : (c) Converging film

Description : Which of the following isn’t the property of a taper roller bearing? (a) High rigidity (b) Easy dismantling (c) Take low radial and heavy loads (d) It is unsuitable for high speed applications

Last Answer : (c) Take low radial and heavy loads

Description : Assertion (A): In hydrodynamic journal bearings, the rotating journal is held in floating condition by the hydrodynamic pressure developed in the lubricant. Reason (R): Lubricant flows in a converging-diverging channel. [IES-1994] ... A (c) A is true but R is false (d) A is false but R is true

Last Answer : (a) Both A and R are individually true and R is the correct explanation of A

Description : Which one of the following types of bearings is employed in shafts of gearboxes of automobiles? [IES-1999] (a) Hydrodynamic journal bearings (b) Multi-lobed journal bearings (c) Antifriction bearings (d) Hybrid journal bearings

Last Answer : (c) Antifriction bearings

Description : Which one of the following pair is correctly matched? [IES-2000] (a) Beauchamp tower ........................First experiments on journal bearings (b) Osborne Reynolds ........................ ... .Pivot and Collar bearings (d) Ball bearings...............................Hydrodynamic lubrication

Last Answer : (a) Beauchamp tower ........................First experiments on journal bearings

Description : Assertion (A): Oil as a cutting fluid result in a lower coefficient of friction. Reason (R): Oil forms a thin liquid film between the tool face and chip, and it provides 'hydrodynamic lubrication'. [IES- 2000] (a ... explanation of A (c) A is true but R is false (d) A is false but R is true

Last Answer : (c) A is true but R is false

Description : The dynamic load-carrying capacity of a bearing is defined as the radial load in radial bearings that can be carried for a minimum life of 1000 revolutions. (a) True (b) False

Last Answer : (b) False

Description : The dynamic load carrying capacity of a bearing is defined as the radial load in radial bearings that can be carried for a minimum life of 1000 revolutions. a) True b) False

Last Answer : b) False

Description : A journal bearing is a ______ contact bearing working on the hydrodynamic lubrication and which supports load in____ direction. a) Sliding, Axial b) Rolling, Radial c) Sliding, Radial d) Rolling, Axial

Last Answer : c) Sliding, Radial

Description : Assertion (A): In equilibrium position, the journal inside a journal bearing remains floating on the oil film. [IES-1995] Reason (R): In a journal bearing, the load on the bearing is perpendicular to the axis of the ... explanation of A (c) A is true but R is false (d) A is false but R is true

Last Answer : (b) Both A and R are individually true but R is not the correct explanation of A

Description : Which of the following are not true for petroff’s equation? a) Shaft is considered concentric with the bearing b) Bearing is subjected to light load c) Is used to find coefficient of friction d) Frictional torque is given by fpr2l

Last Answer : d) Frictional torque is given by fpr2l

Description : In hydrodynamic lubrication, film thickness remains unaffected by change in speeds. a) True b) Increase with increase in speed c) Decrease with increase in speed d) Disappear as the speed tends to infinty

Last Answer : b) Increase with increase in speed

Description : Which one of the following bearing is intended for a very heavy radial load? (a) Ball bearing (b) Self-aligning roller bearing (c) Roller bearing (d) Thrust bearing

Last Answer : (b) Self-aligning roller bearing

Description : Which of the following cannot take the radial load? (a) Cylindrical Roller bearing (b) Taper roller bearing (c) Thrust ball bearing (d) Spherical roller bearing

Last Answer : (c) Thrust ball bearing

Description : Which of the bearings given below SHOULD NOT be subjected to a thrust load? (a) Deep groove ball bearing (b) Angular contact ball bearing (c) Cylindrical (straight) roller bearing (d) Single row tapered roller bearing

Last Answer : (c) Cylindrical (straight) roller bearing

Description : Which of the following cannot take radial load? a) Cylindrical Roller bearing b) Taper roller bearing c) Thrust ball bearing d) None of the listed

Last Answer : c) Thrust ball bearing

Description : In hydrodynamic bearing, (A) The axis of journal is eccentric with respect to axis of bearing (B) The axis of journal is concentric with respect to axis of bearing (C) The axis can be either eccentric or concentric depending upon speed (D) None of the above

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Description : For elasto-hydrodynamic lubrication (A) There should be relative motion between the surfaces of the journal and the bearing and wedge shaped clearance space (B) There should be external source like ... be elastic deformation of the parts in contact (D) There should be metal to metal contact

Last Answer : (C) There should be elastic deformation of the parts in contact

Description : For hydrodynamic lubrication (A) There should be relative motion between the surfaces of the journal and the bearing and wedge shaped clearance space (B) There should be external source like pump to ... be elastic deformation of the parts in contact (D) There should be metal to metal contact

Last Answer : (A) There should be relative motion between the surfaces of the journal and the bearing and wedge shaped clearance space

Description : In hydrodynamic bearing, when the shaft begins to rotate in clockwise direction, (A) The journal climbs to the right side of the bearing without metal to metal contact (B) The journal climbs to the left ... sinks down to the bottom of the bearing (D) The journal is at the center of the bearing

Last Answer : (A) The journal climbs to the right side of the bearing without metal to metal contact

Description : Boundary lubricated bearing is (A) Thick film bearing (B) Thin film bearing (C) Hydrodynamic bearing (D) Hydrostatic bearing

Last Answer : (B) Thin film bearing

Description : If we exclude the cost factor, which bearing is preferred? a) Hydrostatic b) Hydrodynamic c) Both are equally preferred d) Cannot be determined

Last Answer : a) Hydrostatic

Description : Hydrodynamic bearing is a self-acting bearing. a) True b) False

Last Answer : a) True

Description : Consider the following pairs of types of bearings and applications: 1. Partial Journal bearing................... Rail wagon axles 2. Full journal bearing ......................Diesel engine crank-shaft 3. Radial bearing ... matched? [IES-2000] (a) 1 alone (b) 1 and 2 (c) 2 and 3 (d) 1, 2 and 3

Last Answer : (b) 1 and 2

Description : Which one of the following sets of parameters should be monitored for determining safe operation of journal bearing? [IES-2000] Oil pressure, bearing metal temperature and bearing vibration (b) ... shaft (c) Bearing metal temperature and oil pressure (d) Oil pressure and bearing vibration

Last Answer : Oil pressure, bearing metal temperature and bearing vibration

Description : A full journal bearing having clearance to radius ratio of 1/100, using a lubricant with μ=28×10-3 Pa s supports the shaft journal running at N = 2400 rpm If bearing pressure is 1.4 MPa, the Somerfield number is [IES-2001] (a) 8×10-3 (b) 8×10-5 (c) 0.48 (d) 0.48×10

Last Answer : (a) S = (μN s /p) (r/c) 2

Description : Consider tile following statements: [IES-1993; 2002; 2006] Radius of friction circle for a journal bearing depends upon 1. Coefficient of friction 2. Radius of the journal 3. Angular speed of rotation of the shaft Which of the ... ) 1,2 and 3 (b) Only 1 and 2 (c) Only 2 and 3 (d) Only 1 and 3

Last Answer : (b) Only 1 and 2

Description : Needle bearing a roller bearing having a number of smaller diameter roller is well suited to a) Application involving oscillating motion b) Exceptionally high load capacity application at low peripheral speed c) Both (a) and (b) d) None of the above

Last Answer : c) Both (a) and (b)

Description : Which of the following isn’t the property of taper roller? a) High rigidity b) Easy dismantling c) Take low radial and heavy loads d) All are the properties of tapper roller

Last Answer : c) Take low radial and heavy loads

Description : The purpose of lubrication in an antifriction bearing is (a) to reduce the friction between balls and races (b) dissipation of frictional heat prevention of corrosion (c) protection of the bearing from dirt and other foreign particles (d) all of the mentioned

Last Answer : (d) all of the mentioned

Description : Tapered roller bearings can take (a) radial load only (b) axial load only (c) both radial and axial loads and the ratio of these being greater than unity (d) both radial and axial loads and the ratio of these being less than unity

Last Answer : (c) both radial and axial loads and the ratio of these being greater than unity

Description : What type of bearing will you recommend for use in the conveyor belt roller? (a) Ball-bearing (b) Roller bearing (c) Magnetic bearing (d) None of the mentioned

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