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Factors that affect travel life

Hardness factor (fH)

To ensure achievement of the optimum load rating of the Linear Bushing, the raceway hardness must be 58 to 64 HRC. At hardness below this range, the basic dynamic and static load ratings decrease. The ratings must therefore be multiplied by the respective hardness factors (fH).

Temperature factor (fT)

For Linear Bushings used at ambient temperatures over 100℃, a temperature factor corresponding to the ambient temperature, selected from the diagram , must be taken into consideration. For higher than 80℃ application, the seals, end plates, and retainer must be changed for high temperature specifications. (Temperature range: `20℃ ~ 80℃)In addition, please note that the selected Linear Bushing itself must be a model with hightemperature specifications.

Contact factor (fC)

When multiple Linear Bushings are used laid over one another, moments and mounting-surface precision will affect operation, making it difficult to achieve uniform load distribution. For Linear Bushings used laid over one another, multiply the basic load rating (C or CO) by a contact factor selected from the table below.

Number of linear bushings on a shaft Contact facto（r fC）
2
3
4
4
Over 6		 0.81
0.72
0.66
0.61
0.60
In normal use 1.0

Load factor (fW)

In general, machines in reciprocal motion are likely to cause vibration and impact during operation, and it is particularly difficult to determine the magnitude of vibration that develops during hgh-speed operation, as well as that of impact during repeated starting and stopping in normal use. Therefore, where the effects of speed and vibration are estimated to be significant, divide the basic dynamic load rating (C) by a load factor selected from the table below.

Operating conditions Load factor (fW)
Load conditions Speed
No impact and vibration Under 15m/min 1.0~1.5
Slight impact and vibration Under 60m/min 1.5~2.0
Considerable impact and vibration Over 60m/min 2.0~40

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