Calculation of DryLin R

The service life of DryLin maintenance-free linear bearings can be theoretically assessed prior to installation.

Loads
The loads for DryLin maintenance-free linear bearings are given in lbs/in2 (psi). To calculate them, the radial force is divided by the contact surface. Only half the projected surface is taken as a basis for the contact surface, due to the gaps on the inside diameter of the bearing. See example at the bottom of this page.

The maximum permitted load of DryLin maintenance-free linear bearings is dependent on the inside bearing used. Other iglide sleeve bearings can be assembled into the standard DryLin adapters, thereby increasing load capacity. Please consult an iglide sales engineer for information regarding higher load capacity linear bearings.

Speeds
In addition to the maximum permitted speed, the average speed is also very important for DryLin maintenance-free linear bearings. This is of far more significance to the average bearing temperature than the maximum permitted speed.

Average speed = Total travel path per cycle (ft) / Total time per cycle, incl. pause (min)

Compressive strength
The standard DryLin sleeve, part JUI, is made of iglide J. iglide J bearings are not suited for high radial loads. The maximum permissible surface pressure, static, is 5,075 psi. However, wear increases considerably under these loads. iglide J bearings have the highest wear resistance at loads under 300 psi.

Operating Temperature
iglide J bearings can be used at temperatures between -40° F and a maximum of 176° F. Temperatures upwards of 176° F result in increased wear and possibly a loss of pressfit. If long operating times are expected with ambient temperatures reaching 140° F, an adhesive should be used to install the bearing.

Maximum service temperatures of iglide J

	Wear barrier (° F)	Continuous Operation (° F)	Short-term (° F)
	176	176	248

Sliding coefficient of friction for iglide J against steel

	Dry	Grease	Oil	Water
iglide J	0.06-0.18	0.09	0.04	0.04
Steel shaft: hardness 50 HRC, Ra = 8-16 RMS

Maximum surface velocity

		Rotating	Oscillating	Linear
	Continuous	295	295	1560
	Short-term	585	585	2950

Illustration 100.3 Calculation of the projected surface bearing surface area = d1 x b1 x .5 Pressure (psi) = Load / (d1 x b1 x .5) ie: RJUI-01-08 with a radial load of 50 lbs Surface area = .5 x 1.250 x .5 Surface area = .3125 P = 50 / .3125 P = 160 psi