Large diameter dirt and oil seal for a traction motor gearcase

#This invention relates generally to dirt and oil seals for gear train housings associated with axle-mounted electric traction motors of electrically propelled traction vehicles, and it relates more particularly to an improved arrangement for sealing the annular gaps between gearcase sidewall and both the hub of an axle gear and the thrust flange of an adjacent motor support axle bearing.

#Propulsion of an electric or a diesel-electric locomotive is accomplished by means of a plurality of traction motors mounted on the trucks of the locomotive between the wheels that are affixed to opposite ends of the respective axles. As is shown, for example, in U.S. Pat. No. 2,954,263, such a motor typically is hung from the associated axle, with its magnet frame or stator being supported by the respective housings of a pair of axle bearings. The pinion end of the motor shaft is drivingly coupled to the associated axle-wheel set by suitable gearing housed in a rugged gearcase made of either metal or a suitable non-metallic material. Because of their proximity to the road bed of the railroad track, the gearcase and the axle bearings are exposed during operation of the locomotive to a hostile environment of dirt and other undesirable contaminants. Therefore it is customary in this art to provide various sealing means for impeding ingress of dirt and other foreign matter into the gearcase and bearing regions and for impeding egress of lubricants from these components.

#On the wheel side of a gearcase, a dynamic seal is required in the annular gap between the outboard sidewall of the relatively stationary gearcase and the rotating wheel hub. On the motor side, a static seal is required in the annular gap between the other sidewall of the gearcase and the non-rotatable housing of the motor support axle bearing. In the latter case, however, the static seal does not prevent undesirable migration of lubricating oil from the axle bearing region into the gearcase.

#The invention will be better understood and its various objects and advantages will be more fully appreciated from the following description takn in conjunction wih the accompanying drawings in which:

#FIG. 1 is an isometric view of an axle-hung traction motor and gear train (shown in broken lines), including an exploded view of the gearcase that houses the gear train;

#FIG. 2 is a side elevation, from the commutator end, of the traction motor, axle and gearcase;

#FIGS. 1 and 2 show a conventional traction motor 11 of a traction vehicle such as an electric or diesel-electric locomotive, a pair of axle bearing caps 12 bolted to the motor frame, an axle 13 rotatably captured between the motor frame and axle bearing caps, and a driven wheel 14 affixed to the axle 13. The motor 11 is preferably a conventional d-c traction motor having a stator and a rotor. It is disposed between the illustrated wheel 14 and a companion wheel that share the same axle 13 and form an axle-wheel set therewith. Its stator or frame is mounted on the axle by means of sleeve bearings under the caps 12. At one end of the motor 11 the motor rotor is drivingly coupled to the axle 13 by means of suitable torque amplifying gearing comprising a relatively small diameter pinion 15 on the motor shaft and a large diameter bull gear 16 on the axle 13. This gear train is housed in a gearcase 17 having complementary upper and lower halves 18 and 19, respectively. The gearcase can be fabricated from steel plate, or each half can be molded, stamped or otherwise formed in one piece from plastic material reinforced with glass fibers or the like.

#As is shown in FIG. 2, the lower half 19 of the gearcase 17 is bolted to the motor frame and to one of the axle bearing caps at three places 20, and the two halves are bolted together at 21. For adding lubricant to the gearcase and for checking its level, suitable access openings are provided near the top of the upper half 18 and near the bottom of the lower half 19, and these openings are covered by caps 22. To retain the motor and to prevent rotation of the motor frame, the housing of the motor is also attached to the frame of the locomotive truck. (In accordance with conventional practice, each truck of a locomotive includes a frame supported by coil springs which are seated on the journal boxes located at opposite ends of the respective axles of two or three axle-wheel sets, and the superstructure and power plant of the locomotive are in turn supported on center plates mounted on the frames of two such trucks.)

#Each of the motor support axle bearings is actually a split sleeve bearing comprising a pair of semi-cylindrical half sleeves disposed on opposite sides of the axle 13. The upper half sleeve 23 (see FIG. 3) has a solid metal wall and mates with a concave axle bore of the relatively stationary magnet frame of the motor 11, whereas the second half sleeve has a window in its wall and is disposed in the axle bearing cap 12. The cap 12 is fastened to the motor frame by four bolts 24, thereby clamping both the bearing and the motor to the axle 13. The bearing sleeves are keyed to the motor frame to prevent relative rotation therebetween.