Page 1686 - MiSUMi 2025

[Technical Data]
Designing of Chain Drive Mechanism 2

Q Specification Selection for Low-Speed Operation Q Specification Selection for Low-Speed
In operations using a chain speed of 50 m/min. or less, Operation with Impact Load
chain elongation due to wear can almost be ignored. In operations with a great amount of impact loading due to
Under such low-speed conditions, the service life of the frequent startups, stops, reversing, or braking, the inertia
chain largely depends on its fatigue strength. Low-speed (GD ) of the prime mover and the driven machine needs to
2
operation is more economical than operation under "normal be taken into account.
conditions". Low speed is recommended for operations Under such conditions, exercise extreme caution, as the
with fewer startups and stops that enable smooth power chain can be subjected to loads much greater than in
transmission. Selection of ambient atmosphere, layout, operation under normal conditions.
lubrication, etc. for low-speed operation is the same as that Select the chain using the following formula.
for operation under normal conditions.
Selection should be made in accordance with the following Max. Allowable Max. Working Impact Speed
formula. Tension on ≥ Tension on Chain x Coefficient x Coefficient
Chain (Table 5) (Table 4)
Max. Allowable Max. Working Application Coefficient Speed Coefficient Impact Coefficient
Tension of Chain ≥ Tension on Chain x (Table 1) x (Table 4)
P.B-039 This is a constant, shown in (Table 5), determined by the
2
Table 4. Speed Coefficients ratio of inertia (GD ) of prime mover to driven machine as
Roller Chain Speed Speed Coefficient well as the magnitude of play in the power transmission
0~15 m/min 1.0 mechanism used.
15~30 1.2 When the power transmission mechanism has excessive
30~50 1.4 play, it loads greater impact than those in the table can
50~70 1.6 result.
[1] Operating Conditions Table 5. Impact Coefficient
Same as for "Specifications Selection for Operation under Normal 3.0
Conditions" 2.5
[2] Chain and Number of Small Sprocket Teeth The mechanism has the play.
From the selection guide table 3 (P.B-039), select chain
type and number of small sprocket teeth. 2.0
1.5
[3] Calculating the Chain Speed Impact Coefficient 1.0 The power transmission mechanism has no play by sagging of chain or something like that.
0.8
Based on the sprocket selected (chain pitch, number of teeth) and the 0.6
number of revolutions (rpm), calculate the chain speed as follows. K 0.5
0.4
V : Chain Speed (m/min) 0.3
P: Chain Pitch (mm) R= Converted Inertia of the Motor Shaft of the Load
Inertia of the Motor
V＝ P·N·n (m/min) N: Number of Sprocket Teeth 0.2
1000
n : Rotary of Sprocket Teeth (rpm)
[4] Calculating the Max. Working Load on Chain 0.5 0.6 0.8 2 3 4 5 6 8 10
Calculating the Maximum Working Load on the Chain Winching Conveyor Mill Rollgang
Hoist
F : Load on Chain (kN) Crane Truck
V : Chain Speed (m/min) Inertia Ratio R Flywheel
60·kW
F＝ V (kN) kW: Power Transmission (kW)
[5] Application Coefficient
From the application coefficient table (Table 1), select
the appropriate coefficient.
[6] Speed Coefficient
Based on the chain speed obtained in [3] above,
calculate the appropriate speed coefficient.
[7] Maximum Allowable Tension of Chain
In the formula, substitute the values obtained in [4]~[6]
above as well as the maximum allowable tension for
the chain selected in [2] above. Check whether these
values satisfy the formula. If not, try again with another
chain and sprocket set.
[8] Number of Large Sprocket Teeth, Shaft Diameter, and
Chain
Length same as for "Specification Selection for
Operation under Normal Conditions".
B-041