Mini tractor used Koyo taper roller bearings 32211

Specifications

Description of Tapered roller bearing: 

      Tapered roller bearings are bearings that can take large axial forces (i.e., they are good thrust bearings) as well as being able to sustain large radial forces.

      The inner and outer ring raceways are segments of cones and the rollers are also made with a taper so that the conical surfaces of the raceways and the roller axes if projected, would all meet at a common point on the main axis of the bearing.

      This conical geometry is used as it gives a larger contact patch, which permits greater loads to be carried than with spherical (ball) bearings, while the geometry means that the tangential speeds of the surfaces of each of the rollers are the same as their raceways along the whole length of the contact patch and no differential scrubbing occurs. When a roller slides rather than rolls, it can generate wear at the roller-to-race interface, i.e. the differences in surface speeds creates a scrubbing action. Wear will degenerate the close tolerances normally held in the bearing and can lead to other problems. Much closer to pure rolling can be achieved in a tapered roller bearing and this avoids rapid wear.

      The rollers are guided by a flange on the inner ring. This stops the rollers from sliding out at high speed due to their momentum.

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The larger the half angles of these cones the larger the axial force that the bearing can sustain.

     Tapered roller bearings are separable and have the following components: outer ring, inner ring, and roller assembly (containing the rollers and a cage). The non-separable inner ring and roller assembly is called the cone, and the outer ring is called the cup. Internal clearance is established during mounting by the axial position of the cone relative to the cup.

     Metric tapered roller bearings follow the designation system defined by ISO 355.  

Features of Tapered Roller Bearings:

  Single-row tapered roller bearings have an outer ring, and an inner ring assembly 

consisting of an inner ring and a group of tapered rollers embraced by the basket-shaped cage. The outer ring (cup) is separable from the inner ring assembly.According to 

standardized dimensions of tapered roller bearing specified by ISO, the outer ring or 

inner ring assembly of any tapered roller bearing with standardized dimension could make 

international exchange with the outer ring or inner ring assembly of the same series. That 

is to say, besides external dimensions, tolerances shall be in accordance with the provisions 

of the ISO492 (GB307), the cone angle of the inner ring assembly and cone diameter of 

assembly must also comply with the relevant provisions of the exchange.

   Generally, when cone angle of outer ring raceway of single-row tapered roller bearings is 

from 10°to 19°, they could withstand axial loads and radial loads spontaneously. The big 

the cone angle, the larger the axial loads carrying capacity. Large-sized tapered roller bearings 

with post code plus B, the cone angle is from 25° to 29°, they carry large axial loads. 

In addition, single-row tapered roller bearings have the ability to adjust clearance during 

installation. The inner ring (or outer ring) of double row tapered roller bearings is a whole part. 

The small end face between two inner rings (or outer rings) is similar, there is one middle spacer 

ring between two inner rings, and the clearance is adjusted by thickness of spacer ring, which can 

also be used for adjusting the pre-interference of double row tapered roller bearings.

Applications of Taper roller bearing 

       In many applications tapered roller bearings are used in back-to-back pairs so that axial forces can be supported equally in either direction.

      Pairs of tapered roller bearings are used in car and vehicle wheel bearings where they must cope simultaneously with large vertical (radial) and horizontal (axial) forces. Applications for tapered roller bearings are commonly used for moderate speed, heavy duty applications where durability is required. Common real world applications are in agriculture, construction and mining equipment, axle systems, gear box, engine motors and reducers.

Classification and Models of Tapered Roller Bearings:

1. Single-row Tapered Roller Bearings (30000 series)

 Note: Carry radial loads based joint loads of radial loads and axial joint loads. Bearings with big 

cone angle withstand radial loads based radial loads and axial joint loads, generating added axial 

force under radial loads. Therefore, they are arranged in pairs to take radial loads. The external 

axial force shall be larger than additional axial force for exclusive use. 313 series bearings has big 

contact angle (from 27° to 30°), for taking large axial loads. Contact angle of other series of 

bearings is from 10° to 18°.

 2. Double Row Tapered Roller Bearings (35000 series)

Note: This type of bearings has an outer ring and two inner rings, between which spacer ring is 

arranged. The clearance is adjusted by changing thickness of spacer ring. The bearings are 

capable of taking both radial and axial loads in two directions. The axial deflection in two 

directions of shaft and housing could be limited among bearing clearance range.

3. Four Row Tapered Roller Bearings (330000 series)

Note: This type of bearings has spacer rings for adjusting clearance in both inner rings and 

outer rings. Similar to the performance of double row tapered roller bearings, they have large 

load carrying capability and low limit speed. They are mainly used in heavy machinery, such as 

rolling mills etc.

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