Definition of economic accounting
Economic accounting is an important task in the management of socialist enterprises. Generally speaking, it refers to the use of accounting, statistical accounting and business accounting, and economic activity analysis methods under the guidance of the national unified plan to record the labor occupation, labor consumption and labor results in the production and operation process of the enterprise. Activities for calculation, analysis and comparison. Economic accounting is a comprehensive management work. It involves all units and departments of the enterprise and the whole process of production and operation activities. All employees must be mobilized to participate.
Tapered Roller Bearings
Tapered roller bearings are mainly suitable to carry combined load---radial load and as well as axial load; While steep angle tapered roller bearings (27°-30°) can carry the combined load dominated by the axial load. The tapered roller bearings are separable bearings, their internal assemblies and outer rings can be mounted separately; the radial clearance and axial clearance can be adjusted when mounting and interference fits are also allowed.
Structures
1.30000 type single-row tapered roller bearings
This type of bearings can accommodate the axial displacement and axial load on one direction on the shaft or housing. An additional axial force will be generated under the action of radial load, so the outer ring and inner ring inside the two bearing slewing should be mounted with their end faces with same name opposite each other. When applied separately, the applied axial force must be larger than the additional axial force.
2.350000 and 370000 types of double-row tapered roller bearings
These types of bearings comprise one double-raceway outer ring (one double-raceway inner ring) and two inner rings (two outer rings). There is a spacer between the two inner rings (two outer rings), To change the thickness of the spacer can adjust the bearing clearance. They can carry radial and double-direction axial load simultaneously.
3. 380000 type four-row tapered roller bearings
This type of bearing adopts two double-raceway inner rings, one double-raceway outer rings and two single raceways. There are spacers between inner rings and outer rings used for adjusting bearing clearance. They can accommodate large radial load. But their limit rotational speed is low so they are mainly applied to heavy-duty machines such as rolling mills.
Cage materials
Tapered roller bearings generally adopt steel sheet cages, when with too large sizes, use welded steel sheet cages or steel pinned solid cages.
Permissible tilt angle
Generally, inclination is not allowed between the shaft and the housing on the tapered roller bearings. If any, it should not exceed 2'.
Tolerance and Clearance
Generally, the tolerance classes of tapered roller bearings is P0, also can produce higher tolerance classes bearings according to the requirement of users. The tolerance value is showing in the section [the tolerance of rolling bearing".
Users can adjust for practical clearance for the single-row tapered roller bearings according to different demands. The radial clearance of double-row and four-row tapered roller bearings is showing in the table 1.
Dynamic equivalent radial load
Single-row tapered roller bearings:
Pr = Fr When Fa/ Fr≤e
Pr=0.4Fr+YFa When Fa/Fr>e
When applying single-row tapered roller bearings in pairs, the additional axial force must be counted when computing the equivalent dynamic load of the bearings. The axial load magnitude is influenced by mounting methods and the applied axial load and the detailed computing method is same as angular contact Ball Bearings.
The additional axial load on the single-row tapered bearings can be approximately computed with the equation below:
S=Fr/2Y
Double-row tapered roller bearings:
Fa/Fr≤e Pr=Fr+Y1Fa
Pr=Fr+Y1Fa When Fa /Fr≤e
Fa/Fr>e Pr=0.67Fr+Y2Fa
Pr=0.67Fr+Y2Fa When Fa/Fr>e
Static equivalent radial load
Single-row tapered roller bearings:
P0r=0.5Fr+Y0Fa
If P0r<Fr, take P0r=Fr
Double-row and four-row tapered roller bearings:
P0r=Fr+Y0Fa
In the equation:
Fr Actual radial load of the bearing
Fa Actual axial load of the bearing
e.Y.Y1.Y2.Y0 see the bearings dimension table.
In order to prevent damaging sliding generated between the rollers and raceway, a minimum radial load must be acted on the bearing. The calculating formula is:
Frmin=0.02C
In the equation: Frmin Minimum radial load
C Basic dynamic radial load rating
Single Row Tapered Roller Bearing,Double Row Tapered Roller Bearing,Four Row Tapered Roller Bearing
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