Engineering topics

Akin, L. S.

Publications and source records attributed to Akin, L. S..

23 records · Page 2

NASA NTRS1980

Analytical and experimental spur gear tooth temperature as affected by operating variables

A gear tooth temperature analysis was performed using a finite element method combined with a calculated heat input, calculated oil jet impingement depth, and estimated heat transfer coefficients. Experimental measurements of gear tooth average surface temperatures and instanteous surface temperatures were made with a fast response infrared radiometric microscope. Increased oil jet pressure had a significant effect on both average and peak surface temperatures at both high load and speeds. Increasing the speed at constant load and increasing the load at constant speed causes a significant rise in average and peak surface temperatures of gear teeth. The oil jet pressure required for adequate cooling at high speed and load conditions must be high enough to get full depth penetration of the teeth. Calculated and experimental results were in good agreement with high oil jet penetration but showed poor agreement with low oil jet penetration depth.

Townsend, D. P.↗

NASA NTRS1977

Study of Lubricant Jet Flow Phenomena in Spur Gears: Out of Mesh Condition

Oil jet lubrication on the disengaging side of a gear mesh was analyzed. Results of the analysis were computerized and used to determine the oil jet impingement depth for several gear ratios and oil jet to pitch line velocity ratios. A gear test rig using high speed photography was used to experimentally determine the oil jet impingement depth on the disengaging side of mesh. Impingement depth reached a maximum at gear ratio near 1.5 where chopping by the leading gear tooth limited impingement depth. The pinion impingement depth is zero above a gear ratio of 1.172 for a jet velocity to pitch time velocity ration of 1.0 and is similar for other velocity ratios. The impingement depth for gear and pinion are equal and approximately one half the maximum at a gear ration of 7.0.

Townsend, D. P.↗

NASA NTRS1977

Study of lubricant jet flow phenomena in spur gears - Out of mesh condition

An analysis was conducted for oil jet lubrication on the disengaging side of a gear mesh. Results of the analysis were computerized and used to determine the oil jet impingement depth for several gear ratios and oil jet to pitch line velocity ratios. An experimental program was conducted on the NASA gear test rig using high-speed photography to experimentally determine the oil jet impingement depth on the disengaging side of mesh. Impingement depth reaches a maximum at gear ratio near 1.5 where chopping by the leading gear tooth limits the impingement depth. The pinion impingement depth is zero above a gear ratio of 1.172 for a jet velocity to pitch time velocity ratio of 1.0 and is similar for other velocity ratios. The impingement depth for gear and pinion are equal and approximately one-half the maximum at a gear ratio of 1.0. Impingement depth on either the gear or pinion many be improved by relocation of the jet from the pitch line or by changing the jet angle. Results of the analysis were verified by experimental results using a high-speed camera and a well lighted oil jet.

Townsend, D. P.↗

NASA NTRS1974

Study of lubricant jet flow phenomena in spur gears

Review of the results of lubrication tests conducted in the NASA-Lewis Research Center gear test apparatus modified for high speed photography of gear tooth lubrication. The experimental results are compared with an analytical model that includes windage effects. The resulting findings show that the analytical model provides good agreement with the experimental impingement depth and that small oil drops are affected by gear windage. For this reason, the best lubrication is provided when the oil jet is not atomized.

Akin, L. S.↗

NASA NTRS1974

Study of lubricant jet flow phenomena in spur gears

Lubricant jet flow impingement and penetration depth into a gear tooth space were measured at 4920 and 2560 rpm using a 8.89 cm (3.5 inch) pitch diameter 8 pitch spur gear at oil pressures from 70,000 to 410,000 n/sqm (10 psi to 60 psi). A high speed motion picture camera was used with xenon and high speed stroboscopic lights to slow down and stop the motion of the oil jet. An analytical model was developed for the vectorial impingement dept and for the impingement depth with tooth space windage effects included. The windage effects for oil drop size greater than .0076 cm (.003 inches). The analytical impingement dept compared favorably with experimental results above an oil jet pressure of 70,000 n/sqm (10psi). There was further penetration into the tooth space after impingement, but much of this oil was thrown out of the tooth space without further contacting the gear teeth.

Akin, L. S.↗