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1、Adjust Ring&Pinion GearsCarrier AdjustmentsCarriers require four major adjustments during assembly:1.Pinion bearing preload2.Pinion depth3.Carrier bearing preload4.BacklashPinion Gear AdjustmentsPinion PreloadShimsCollapsible SpacerPinion DepthShimShimMost pinion preload adjustments are made using a
2、 collapsible spacer;some use selective shims.Most pinion depth shims are between the gear head and the bearing;some fit between the bearing cup and the carrier.Crush SleeveThe collapsible spacer,commonly called a crush sleeve,fits between the upper bearing and the lower bearing or gear.Tightening th
3、e pinion shaft nut collapses the sleeve and increases the preload on the bearings.A new crush sleeve is used when the pinion gear is installed.Nut Crush SleeveChecking PreloadThe amount of torque required to rotate the pinion gear is being measured using a low-reading torque wrench.If the amount is
4、too low,the pinion nut will be tightened further to put more preload on the bearings.Low-reading Torque WrenchShim AdjustmentA group of shims are placed between a step on the pinion shaft and the bearings.Thinner shims will increase the amount of bearing preload.Pinion GearPinion Preload ShimsReplac
5、ing DifferentialThe differential and ring gear with the carrier bearings has been placed into the carrier with the ring gear contacting the pinion gear.An adjusting shim is being inserted between the left bearing cup and the housing.ShimCarrierDifferential CaseCarrier Bearing PreloadA shim is being
6、inserted between the right side bearing cup and the housing.The thickness of this(right side)shim and the left side shim will determine carrier bearing preload and back lash.Carrier bearing preload occurs when the shims are thicker than the space.ShimChecking Back LashThe dial indicator is set up us
7、ing a flexible mount.The measuring stylus is against a ring gear tooth.Back lash is read on the dial indicator by rocking the ring gear back and forth while holding the pinion gear stationary.Dial IndicatorRing GearFlexible MountRing Gear Tooth NamesThe heel is the outer end of the ring gear tooth,a
8、nd the toe is at the inner end.The pinion gear exerts driving pressure on the more vertical convex side of the tooth while the more slanted,concave side is called the coast side.Heel ToeCoast Side:ConcaveDrive Side:ConvexContact PatternFace FlankPinion Tooth ContactGear Marking CompoundTo check gear
9、 contact,a thin film of gear marking compound is painted onto the tooth,and the gears are rotated.The rubbing action of the pinion gear should wipe off a contact area that is about one-half the length of the tooth.Marking CompoundA very thin coating of gear marking compound is painted onto the ring
10、gear teeth using a small brush.It is recommended to paint both sides of the gear teeth all the way around the gear.Painted TeethSmall Paint BrushRunning a PatternThe pattern will be more distinct and realistic as more load is placed on the gears.The screwdriver is being used as a brake to retard the
11、 ring gear as the pinion gear is being turned.Note that all of the ring gear teeth should be painted to check the contact of all of the ring gear teeth.ScrewdriverA Good PatternThe drive sides of these teeth show a good contact.The pattern is about one-half the length of the tooth and favors the toe
12、.Under load,the tooth will deflect slightly,and the pattern should become centered.Gear ContactMarking Compound(yellow)(Photo Courtesy of Sean Boyle)Ideal Contact LocationToeHeelDrive SideCoast SideGear Marking CompoundPinion Tooth ContactThe contact pattern should be centered vertically and horizon
13、tally on the tooth and should not run off the tooth.Some technicians prefer that the pattern be shifted slightly toward the toe.Ideally,the pattern should have sharp edges without any smearing.Ring&Pinion GearsThe carrier and pinion gear bearings must be adjusted to the proper preload before trying
14、to run a contact pattern and adjusting pinion depth or backlash.Pinion BearingsCarrier BearingsPinion Too ShallowThis pattern which runs off of opposite ends of the tooth shows that the pinion gear needs to be moved toward the ring gear.This will require a different pinion depth shim.ToeHeelCoast Si
15、deDrive SideThicker Pinion Depth ShimThicker Pinion Depth ShimA thicker pinion depth shim will move the pinion gear downward,deeper into the ring gear.Changing the shim requires that the carrier be disassembled completely and then reassembled.Pinion Too DeepThis is the opposite problem from Slide 17
16、 with the patterns running off the other ends of the teeth.This pinion gear is too deep and must be moved out of the ring gear a slight amount.ToeHeelDrive SideCoast SideReduce Pinion Depth ShimThinner Pinion Depth ShimA thinner pinion depth shim will move the pinion gear upward,less deep in the rin
17、g gear.Changing the shim requires that the carrier be disassembled completely and then reassembled.Alternate Pinion Depth ShimSome drive axles use a removable pinion retainer with depth shims between the retainer and carrier.Pinion depth can be adjusted without disturbing pinion bearing preload.Carr
18、ierPinion RetainerPinion Depth ShimPinion GearInsufficient LashBoth patterns are off the toes of the teeth.This tells us that the ring gear is too close to the pinion gear,and there is not enough back lash.ToeHeelDrive SideCoast SideShift Carrier Bearing Shims,Increase LashMoving part of the shim pa
19、ck from the left side to the right side will move the ring gear away from the pinion gear and increase back lash.Shim MovementExcess LashToeHeelDrive SideCoast SideBoth patterns are off the heels of the teeth.This tells us that the ring gear is too far away from the pinion gear,and there is too much
20、 back lash.Shift Carrier Bearing Shims,Reduce LashMoving part of the shim pack from the right side to the left side will move the ring gear closer to the pinion gear and reduce back lash.Shim MovementThreaded Lash AdjustmentThis carrier has a threaded adjuster at each of the carrier bearings.These a
21、djusters can be turned inward or outward to adjust carrier bearing preload and lash.Adjuster NutCarrierCompletionWhen the carrier has the proper back lash(at a minimum of four locations around the ring gear),the proper preload,and a good pattern all the way around the ring gear,the carrier bearing cap bolts should be tightened to the correct torque.The axle assembly can be assembled and filled with the proper lubricant to the correct level.