Spherical roller bearings are normally used
It is also true for (a) but (d) is more appropriate.
The life of a ball bearing at a load of 10 kN is 8000 hours. Its life in hours, if the load is increased to 20 kN, keeping all other conditions the same, is
The basic load rating of a ball bearing is
To restore stable operating condition in a hydrodynamic journal bearing, when it encounters higher magnitude loads,
In thick film hydrodynamic journal bearings, the coefficient of friction
Consider the following statements about antifriction bearings:
1. Their location influences the lateral critical speed of a rotor.
2. Roller bearings are antifriction bearings. Which of the statements given above is/are correct?
In three ball bearing identified as
SKF 2015, 3115 and 4215
According to ISO plan for dimension series bearings are provided with two digit numbers. The first number indicates the width series 8, 0, 1, 2, 3, 4, 5 and 6 in order of increasing width. The second number indicate diameter series 7, 8, 9, 0, 1, 2, 3, and 4 in order of ascending outer diameter of bearing. Thus bearing number SKF 2015, 3115 and 4215 shows bearings belonging to different series with 75 mm bore diameter but width is increasing. SKF 2015, 3115 and 4215 shows width is increasing ascending outer diameter of bearing same bore diameter 75 mm. (i.e. 15 × 5)
The rating life of a group of apparently identical ball bearings is defined as the number of revolutions or exceeded before the first evidence of fatigue crack by:
The rolling element bearings are
On what does the basic static capacity of a ball bearing depends?
In a single row deep groove ball-bearing, cages are needed to
Assertion (A): It is desirable to increase the length of arc over which the oil film has to be maintained in a journal bearing.
Reason (R): The oil pressure becomes negative in the divergent part and the partial vacuum created will cause air to leak in from the ends of bearing.
Removal of metal particles from the raceway of a rolling contact bearing is a kind of failure of bearing known as
Assertion (A ): Tapered roller bearings are sensitive to the tightening between inner and outer races.
Reason (R): Tapered roller bearings are always provided with adjusting nut for tightening.
Match List-I (Bearings) with List-II (Applications) and select the correct answer using the codes given below the lists:
Tapered roller bearings can take
Which of the following are included in the finishing operations for porous bearing?
1. Infiltration 2. Sizing 3. Heat treatment 4.Coining
Select the correct answer using the code given below:
Which one of the following is correct?
A hydrodynamic slider bearing develops load bearing capacity mainly because of
A hydrodynamic slider bearing develops load bearing capacity mainly because of wedge shaped oil film.
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?
When the load and speed is doubled, the minimum film thickness remains unchanged. Since,
Since S remains the same even after doubling the speed as well as load and film Thickness depends on the Sommerfeld number.
What is the main advantage of hydrodynamic bearing over roller bearing?