What Are Our Concerns About Bearings（49）

Q1:What is the role of ball bearing between wheel and shaft?

A:Reduce the friction between wheel and shaft, and transform sliding friction into rolling friction

Q2:What is the difference between bearing and bearing seat? What is their role?

A:Bearings are used to make the shaft run along the circumference and support the shaft, the conventional use is two bearings or more than two, its role is to make the shaft run normally.
The bearing seat is used to support the bearing, fixing the outer ring of the bearing, only allowing the inner ring to rotate, the outer ring remains stationary, always in line with the direction of the transmission (such as the direction of the motor), and maintain balance  

Q3:What is the role of thrust bearing?

A:The thrust bearing is used to bear the axial thrust of the rotor in operation, and to determine and maintain the axial mutual position between the turbine rotor and cylinder.  

Q4:How to operate the bearing selection, what parameters need to be determined?

A:There are several types of bearings, according to the structure points, according to the force points, according to the use points, according to the accuracy of the classification.  In general, ordinary machinery with ordinary precision bearings, machinery with special requirements to consider the choice of bearings, to meet the working performance requirements is a, and then consider the service life, price, maintenance, etc..  
Dimensions on three dimensions: diameter, diameter, thickness;  
The types are: ordinary precision, precision, super precision;
Uses: common, high speed, heat resistance, dust resistance, heavy duty, etc.  
Determine 3 dimensional parameters: inside diameter, outside diameter, thickness;  Check the table for the corresponding model, or directly buy bearings according to the three parameters.

Q5:What is the geometry of bearing 6204?

A:Some parameters of 6204.  
Model: 6204  
Brand: FAG  
Type: deep groove ball bearing  
Inside diameter: 20 mm  
Outer diameter: 47 mm  
Thickness: 14 mm  
Remark: Single row deep groove ball bearings, open type  
The use of 6204 bearings  
6204 bearing belongs to deep groove ball bearing series, mainly used for vulcanizing machine, other reducer, comprehensive experiment, vacuum system, air curtain machine, plant determination, packaging machinery, combination machine tool, woodworking machine tool, vehicle lamp and other equipment.  

Q6:What is a high-speed rail bearing? What is it used for?

:High-speed railway bearings are used in high-speed railway vehicles. They have high speed, radial load and wear resistance. They are usually called high-speed railway bearings when the speed exceeds 160 km per hour.  
Although China has been able to produce high-speed railway emU complete cars with independent intellectual property rights, but there is still a gap in the domestic application of high-speed railway bearings.  At present, domestic emU bearings are all imported bearings.  Therefore, it is imperative to vigorously develop the localization of high-speed railway bearings.  

Q7:What is used type of ball screw bearing ?

A:Ball screw support bearings are generally used deep groove ball bearings  
Specific type, depends on the diameter of the screw end part of the bearing position and the diameter of the inner hole of the bearing seat, as well as the required load and speed
Generally 32 diameter lead screw with 25X62  
Use 30X62 for 40 diameter, 40X90 for 50 diameter, etc  

Q8:What is the hardness of GCR15 bearing steel pipe after quenching treatment?

A:In general, after annealing of GCR15 bearing steel tube, it is ok to reach the hardness of 60. Specifically, it depends on the corresponding use of heat treatment process parameters:  

• Ordinary annealing: 790-810 ℃ heating, furnace cooling to 650 ℃, air cooling — HB170-207  
• Isothermal annealing: 790-810 ℃ heating, 710-720 ℃ isothermal, air cooling — HB207-229  
• Normalizing: 900-920 degrees heating, air cooling — HB270-390  
• High temperature tempering: 650-700 degrees heating, air cooling — HB229-285  
• Quenching: heating at 860 degrees, oil quenching — HRC62-66  
• Low temperature tempering: 150-170 degrees tempering, air cooling — HRC61-66
• Carbonitriding: 820-830 degrees for 1.5-3 hours, oil quenching, -60 degrees to -70 degrees cryogenic treatment +150 degrees to +160 tempering, air cooling — HRC≈67  
  I think the hardness should be HRC61-65.  

Q9:What is the role of the throttle hole on the bearing inlet pipe?

A:Bearing inlet tubing is equipped with throttle holes, generally installed on the lower tile.  Through the throttle hole to control the amount of oil, so that the oil temperature rise is maintained at 12~15℃, to ensure the normal operation of the bearing bush.  

Q10: 355KW motor load side has two bearings, the same outer diameter, placed in parallel, what is the role?  

Shock absorption, pressure resistance, easy installation

Q11: How to distinguish the type and type of bearings without number?

A:General bearing code is 5 digits: XX X XX  

• 1. the last two are the inside diameter,  

For the common inner diameter d=20 ~ 480mm bearing inner diameter is generally a multiple of 5, these two numbers represent the bearing inner diameter size divided by 5 quotient, such as 04 represents D = 20mm;  12 means d = 60mm and so on.  For bearings with inner diameters of 10mm, 12mm, 15mm and 17mm, the inner diameters are 00, 01, 02 and 03 respectively.  For bearings with inner diameter less than 10mm and greater than 500mm, the inner diameter expression method is otherwise stipulated, which can be referred to GB/T272-93.  

• 2. The diameter series of bearings is represented by the third digit from the right of the basic code.  

For example, for centripetal bearings and centripetal thrust bearings, 0 and 1 represent extra-light series;  2 indicates light series;  3 indicates the medium series.  4 indicates the repeated series.  The size pairs between the series are shown in the figure below.  The thrust bearing is the same as the centripetal bearing except that 1 is used to represent the extra-light series.  

• 3. The width series of bearings is represented by the fourth digit from the right of the basic code.  

When the comparison of the width and diameter series is listed as 0 series, the width series code O can not be marked in the code for most bearings, but for self-aligning roller bearings and tapered roller bearings, the width series code 0 should be marked.  And diameter series code and width series code collectively referred to as the size series code.  

• 4. bearing type code with the basic code number from the right of the fifth digit (cylindrical roller bearings and needle bearings and other types of code for letters).  

Q12:What kind of bearings are car wheel bearings? What models are most of them?

A:Common is ball bearings and roller bearings, turbocharger is full floating bearings, many models, each model has a corresponding model, and a car has a lot of different sizes of different models of bearings.