1) Spring Support
Number of bearing division AB (Aft Bear) ; 50
FB (Fore Bear) ; 10
2) Oil Film Support
Shaft rotating speed; 30 rpm
Viscosity of lub. oil;
12.7×10-7N-s/cm2 (1.23 ×10-7 kgf-s/cm2)
(Equivalent to SAE30 at 35 deg. C)
5. RESULTS OF CALCULATION
5.1 Simple Support Calculation (Refer Fig.3-1)
5.1.1 Single Slope
As the AOS (AB/A Offset) increase, deflection of AB/F decrease. When the AOS becomes 0.25, the shaft begins to touch on to the bearing surface at AB/F. Consequently the Support Point Load of AB/F begins to increase.
When the AOS becomes 0.3, deflection of FB/F becomes plus value and the shaft begins to float in the bearing at FB/F. Consequently the Bearing Load of FB and Local Unit Load of FB/F become zero.
Although the Relative Inclination at AB/A decreases with the increasing of AOS, when the touching of shaft begins the Relative Inclination at AB/A stops to decrease and begins to increase slightly.
5.1.2 Partial Slope
As the AOS increase, deflection of AB/M decrease. When the AOS becomes 0.15, the shaft begins to touch on to the bearing surface at AB/M. Consequently the Support Point Load of AB/M begins to increase.
When the AOS becomes 0.15, deflection of FB/F becomes plus value and the shaft begins to float in the bearing at FB/F. Consequently the Bearing Load of FB and Local Unit Load of FB/F become zero.
Although the Relative Inclination at AB/A decreases with the increasing of AOS, when the touching of shaft begins, the Relative Inclination at AB/A stops to decrease and begins to increase slightly.
The Relative Inclination at AB/M increases. This is a logical result because slope is not provided on the fore half of the bearing.
5.1.3 Double Slope
General feature is same as that of Partial Slope except the Relative Inclination at AB/M. Although the Relative Inclination at AB/M increases with the increasing of AOS, when the touching of shaft begins at AB/M, the Relative Inclination at AB/M stops to increase.
5.2 Spring Support Calculation (Refer Fig.3-2)
5.2.1 Single Slope
General tendencies of Deflection at AB/F, AB/M, FB/F and Relative Inclination at AB/A, AB/M are same as the case of Simple Support. Regarding the deflection, both values at AB/F and AB/M slightly decrease comparing with the case of Simple Support. This is due to that the shaft sinks on the bearing because AB is treated as Spring Support. Consequently the Bearing Load of AB and Relative Inclination at AB/A are increased a little bit.
Although the general tendency of Partial Load of AB is same as that of Support Point Load of Simple Support, AB/A is a little higher and AB/F is a little lower in the values of load.
General tendency of Local Unit Load is similar to that of Partial Load.
5.2.2 Partial Slope
General tendencies of Deflection at AB/F, AB/M, FB/F and Relative Inclination at AB/A. AB/M are same as the case of Simple Support. Regarding the deflection, both values at AB/F and AB/M slightly decrease comparing with the case of Simple Support. Consequently the Bearing Load of AB and Relative Inclination at AB/A are increased a little bit.
Although the general tendency of Partial Load of AB is same as that of Support Point Load of Simple Support, regarding the value of load, AB/A is a little higher and AB/M is a little lower.
General tendency of Local Unit Load is similar to that of Partial Load.
5.2.3 Double Slope
General feature is same as that of Partial Slope except the Relative Inclination at AB/M.
Although the general tendency of Relative Inclination at AB/M is same as the case of Simple Support, the value is a little higher than the case of Simple Support.
Regarding the Local Unit Load of AB, the value of AB/A increases and AB/M decreases a little bit.
5.3 Oil Film Support (Aft ST Bear only) Calculation (Refer Fig.3-3)
5.3.1 Single Slope
In the all range of AOS, Deflection of FB/F is large and Bearing Load of FB is zero. This is due to that oil film is made on the bearing and the shaft is lifted up. Characteristic curves of Bearing Load, Partial Load and Relative Inclination are of smooth figure. This is the noteworthy point which is different from the cases of Simple Support and Spring Support that there are knuckle points in the characteristic curves.
As the AOS increases, Bearing Load of AB increases. In the Partial Load, AB/Ahalf decreases and AB/Fhalf decreases. Thickness of Oil Film at AB/A increases and those at AB/M and AB/F decreases. Regarding the Press. of Oil Film, maximum press. in the bearing (AB/Pmax) decreases steeply and press. at AB/M increases gradually. Position of Pmax moves to inner side of the bearing and it can understand that distribution of oil film pressure in the bearing is leveled as the AOS increases.
