Adjustment principle
The distance between the axis of the differential and the end face of the drive gear determines the location of the contact patch in the engagement of the final drive gears. When installing the output shaft in the gearbox, this distance affects the degree of wear and noise of the final drive gears. Therefore, it must be adjusted with great care using a special tool.
The initial value for adjustment is the calculated value of the distance between the axis of the differential and the end face of the drive gear (fixed size «R o», equal to 50.70 mm, see diagram), corrected by the amendment «r», determined during the manufacture of the drive gear Correction value «r» indicated in hundredths of a millimeter, always with a sign «+» on the driven gear of the main gear. For example, if the driven gear is labeled «25», it means that «r» equals 0.25 mm. The adjustment consists in placing the adjusting ring S3 of the required thickness under the outer ring of the rear output shaft bearing to displace the drive gear in the gearbox housing.
Determination of the correction value «r»
Note. This measurement is made if there is no correction mark on the driven gear of the final drive «r» in hundredths of a millimeter from the nominal position of the drive gear, and also if parts that directly affect the position of the final drive gear have been replaced (output shaft rear double row tapered roller bearing, crankcase or gearbox rear cover, 1st gear gear bearing).
Remove the gearbox rear cover.
Install the VW 381/11 mounting bracket and fix it strictly at a right angle relative to the output shaft by hand-tightening two M6x50 bolts.
Bolts are tightened to 200 Ncm using a torque wrench.
The drive gear, after tightening the bolts, takes the position that it occupied when the rear gearbox cover was installed. This operation must be carried out very carefully whenever the distance between the end of the pinion gear and the axle of the differential is adjusted.
Remove differential.
Fit measuring mandrel VW 385 with indicator VW 385-30 into the clutch housing with a foot preload of 2 mm. Set arrow to «zero».
Determine the estimated size «r», representing a deviation from the size «R o», according to the maximum deviation of the indicator needle (to the starting point about the opposite direction).
When replacing parts by selecting the thickness of the adjusting ring, achieve the maximum possible accuracy in maintaining the size «r».
Selection of the adjusting ring of the rear bearing of the secondary shaft
I. After replacing the parts that determine the position of the final drive gear.
Press the output shaft rear double row tapered roller bearing outer race together with the old adjusting ring into the gearbox housing «S 3».
Install the selected output shaft into the gearbox housing and press in the second inner race of the output shaft rear bearing.
Clamp the gearbox housing in a vice with pads of soft material and tighten the nut at the rear end of the output shaft to a torque of 10.0 kgf·m.
Install a new gasket on the gearbox housing, connect the gearbox housing together with the output shaft to the clutch housing and secure them with four bolts.
Measure the value again «r» using the universal measuring mandrel VW 385/1.
If «r 1» less than «r», then it is necessary to put an adjusting ring of increased thickness. If «r 1», more than «r», it is necessary to install an adjusting ring of a smaller thickness.
Example.Let's assume that the value «r» is 0.45 mm, and the value «r 1» - 0.36 mm. Value «r 1» less than «r». Therefore, the thickness of the adjusting ring must be increased by the difference between «r» And «r 1». According to the formula S3 =S'3 + (r-r 1) we determine the thickness of the adjusting ring installed under the outer ring of the rear bearing of the secondary shaft, where:
S3 - the thickness of the new adjusting ring;
S'3 - the thickness of the old adjusting ring, equal to, say, 0.80 mm;
g - the calculated value of the amendment to the nominal position of the main gear;
g1 is the actual value of the correction to the nominal position of the final drive gear.
S 3 =0,80+ (0,45-0,36) =0.80+0.09=0.89 mm
II. After changing main gear
Note. The method described below for selecting the adjusting ring of the rear output shaft bearing is used only if the final drive is replaced. If any parts that determine the position of the final drive gear have been replaced, the selection is made as described above.
Press the outer race of the output shaft rear bearing without the old adjusting ring into the rear cover of the gearbox housing «S 3», using support ring 30-205 and mandrels 30-505 and VW 412.
Install the output shaft into the rear cover of the gearbox housing and press on the inner rear bearing of the output shaft.
Rotate output shaft several times in both directions.
Clamp the gearbox housing in a vice with pads of soft material and tighten the nut at the rear end of the output shaft to a torque of 10.0 kgf·m.
Install a new gasket on the gearbox housing, connect the gearbox housing together with the output shaft to the clutch housing and secure them with four bolts.
Install the VW 381/11 mounting bracket and fix it strictly at a right angle relative to the output shaft by hand-tightening two M8x50 bolts.
Tighten the bolts to 200 Ncm using a torque wrench.
The drive gear, after tightening the bolts, takes the position that it occupied when the gearbox rear cover was installed. This operation must be carried out very carefully every time. when adjusting the distance between the end face of the drive gear and the axle of the differential.
Set the movable adjusting ring of the measuring mandrel VW 385/1 to the dimension «A» (see photo), equal to 50 mm.
Attach an indicator to the measuring mandrel «WITH» with 0-3 mm scale and 12.3 mm extension.
Adjust caliber VW 385/30 to the calculated distance «R o» between the end of the drive gear and the axle of the differential, equal to 50.70 mm, and install the gauge on the measuring mandrel. Set the indicator needle to zero with the stem preloaded at 2 mm.
Using the knurled screw, move the movable adjusting ring back as far as it will go.
Fit ring VW 385/17 on the pinion head and insert the universal measuring mandrel into the clutch housing.
Warning. During measurement, the leg of the indicator extension must always rest against the ring in order to prevent the ring from moving off the pinion gear head when the leg is retracted.
Install the differential case cover with the differential outer bearing pressed in and secure it with four bolts.
Pull back the second shim as far as possible using the movable adjusting ring until the measuring mandrel can only be turned by hand.
Slightly turn the measuring mandrel in both directions so that the indicator foot rests against the ring mounted on the head of the drive gear, and the indicator needle deviates (to the starting point of the movement in the opposite direction). Let the value thus measured «r» was 0.15 mm.
Calculate the thickness of the adjusting ring «S 3» according to the formula:
S 3 =r 1 +r,
Where:
r1 — measured value according to the maximum deviation of the indicator pointer;
r is the value of the correction to the nominal position of the drive gear of the final drive, marked on the driven gear or measured, as in our case, and equal to 0.45 mm.
Example. «r 1» equal to 0.15 mm; «r» - 0.45 mm.
S3 =0.15+0.45=0.60 mm.
Since the thickness tolerance limits of the shims are known, the shim can be accurately matched in all cases «S 3» calculated thickness.
Checking the adjustment of the distance between the end face of the drive gear and the axle of the differential
Install the output shaft, press in the outer race of the rear bearing, placing the selected adjusting ring «S 3».
Install the universal measuring mandrel and carry out a check measurement.
With a correctly selected adjusting ring, the indicator should show the amount of the correction «r» with a deviation of±0.04 mm. Read the indicator readings in a counterclockwise direction.
Adjustment of the side clearance in the gearing of the final drive gears and the preload of the bearings of the differential box
This adjustment is necessary when replacing the main gear of the gearbox housing, differential box and bearings, as well as when adjusting the distance between the end face of the drive gear and the differential axle.
The differential bearings must be installed with a preload of 0.40 mm.
The preload of the differential bearings and the side clearance in the meshing of the final drive gears are provided by selecting the thickness of the adjusting rings S1 and S2 (see diagram).
Adjustment and measurement of the distance between the end face of the drive gear and the axle of the differential and the side clearance in the gearing of the main gear gear:
1 - rear comic roller bearing of the secondary shaft;
2 - differential bearing;
3 - clutch housing;
R0 — estimated distance between the end face of the drive gear and the axle of the differential;
r - correction to the calculated distance between the end face of the drive gear and the axle of the differential (applied to driven gears supplied as spare parts);
S1, S2 - differential bearing preload adjustment ring;
S3 - adjustment ring for the distance between the end of the drive gear and the differential axle
Remove the o-rings, press the outer rings of the differential bearings out of the clutch housing and remove the adjusting rings.
Press in the outer race of the tapered roller bearing from the side opposite the teeth of the driven gear of the final drive, with the setting ring «A» (see diagram) 1.20 mm thick.
Press in the differential bearing outer race on the side of the driven gear teeth without the shim to the stop.
Install the differential with pressed-on bearing inner races without the speedometer drive gear, install the differential cover and tighten the nuts of its fastening bolts crosswise.
Install the differential so that its axis is in a vertical plane (see diagram).
Install the indicator support mandrel VW 385/17 on the differential box.
Fasten the indicator with a scale of 0-3 mm with the VW 322/8 extension 22 mm using the VW 387 tool. Mount the indicator leg on the support mandrel with a preload of 1 mm. In this position, fix the indicator and install it on «zero».
Install clamping sleeve VW 521/4 with sleeve VW 521/8 on the differential cover (see diagram).
By moving the differential up and down, determine the axial movement by the indicator «IN» differential, which, for example, is equal to 0.30 mm.
Warning. To accurately measure the axial movement of the differential, do not rotate the differential during the measurement, thereby eliminating self-alignment of the bearings.
Using the formula Sabout =A + B + C, calculate the total thickness of the adjusting rings of the differential box bearings, where:
Sabout - the total thickness of the adjusting rings «S 1» And «S 2» (see diagram) differential box bearings;
A - thickness of the adjusting ring, equal to 1.20 mm;
B - the value of the axial movement of the differential;
C - the value of the preload of the bearings of the differential box.
Sabout =1.20+0.30+0.40=1.90 mm.
According to the formula S1 \u003d B + C, temporarily determine the thickness of the adjusting ring «S 1» differential bearing mounted on the side opposite to the teeth of the driven gear.
S1 =0.30+0.40=0.70 mm.
Remove the differential cover, press out the bearing outer race and install the shim «S 1» 0.70 mm thick.
Press in the differential bearing outer race and install the differential cover.
Install output shaft with matched ring «S 3», which determines the distance between the end face of the drive gear and the axis of the differential (selection method described above).
Rotate the differential several times to self-align the bearings.
Install instruments for measuring the backlash between the teeth of the drive and driven gears during rotation of the differential and with the output shaft stationary; the measurement is taken along the diameter at a distance of 71 mm from the axis of the differential. The side clearance between the teeth of the driving and driven gears should be within 0.10-0.20 mm.
Install the VW 381/11 mounting bracket and fix it strictly at a right angle relative to the output shaft by hand-tightening two M8x50 bolts.
Tighten the bolts to 200 Ncm using a torque wrench.
The drive gear, after tightening the bolts, takes the position that it occupied when the gearbox rear cover was installed. This operation must be carried out very carefully whenever the distance between the end of the pinion gear and the axle of the differential is adjusted.
Turn the driven gear to the stop and set the indicator 8 to the zero position. Return the driven gear by rotation all the way back and measure the backlash between the teeth of the driving and driven gears. Record the indicator readings.
Loosen the locking bolt of the differential clamping sleeve and the bolts securing the output shaft mounting bracket.
Repeat the above operation three times, each time turning the driven gear 90°.
Warning. If the values obtained during measurement differ from one another by more than 0.06 mm, then the driven gear or the main pair are not installed correctly. Check the correct assembly and, if necessary, replace the main pair.
Calculate the average backlash between the teeth of the drive and driven gears.
Example. Suppose the value of the side clearance at the first measurement is 0.45 mm, at the second - 0.47 mm, at the third - 0.46 mm, at the fourth - 0.46 mm, i.e. the average gap is (0,45+0,47+0,46+0,46).46) /4=0.46 mm.
Calculate the thickness of the adjusting ring «S 2» ps formula S2 = (A-B) +C, where:
S2 - the thickness of the adjusting ring installed under the outer ring of the differential bearing from the side of the ring gear of the driven gear;
A - thickness of the adjusting ring, equal to 1.20 mm;
B is the value of the average side clearance between the teeth of the driving and driven gears;
C - estimated thickness of the ring «SS 2» (constant), equal to 0.15 mm.
Example.In our example «A» equal to 1.20 mm, «IN» - 0.46 mm, «WITH» - 0.15 mm.
S 2 = (1,20—0,46) +0.15=0.89 mm.
Calculate the thickness of the adjusting ring «S 1» under the outer ring of the differential bearing, mounted on the side of the driven gear ring gear, according to the formula S1 \u003d Sabout -S2.
Example. In our example «Sv» equal to 1.90 mm, «S 2» - 0.89 mm.
S1 -1.90-0.89=1.01 mm.
Since the thickness of the shims is known, shims of the calculated thickness can be matched with high accuracy in all cases.
Measure the thickness of the adjusting rings around the circumference with a micrometer at several points. In addition, make sure that there are no burrs or other defects on the surface of the rings.
Install, observing the methods described above, under the outer rings adjusting rings of the required thickness «S 1» And «S 2» differential box bearings.
Measure the backlash between the teeth of the driving and driven gears at four points along the circumference. The gap should be within 0.10-0.20 mm.
Warning. The measurement results should not differ from each other by more than 0.05 mm.
If new bearings are installed, check the moment of resistance to rotation of the differential, which should be equal to 250 Ncm.
Calculation of the thickness of the adjusting rings of the rear bearings of the primary and secondary shafts
Note. This operation must be carried out very carefully, since the thickness of the shim and gasket affect the position of the final drive gear. Measurements must be made with the outer races of the bearings pressed in as far as they will go.
To select the thickness of the adjusting rings of bearings, it is necessary to determine the following dimensions (see picture):
a - protrusion of the input shaft ball bearing from the gearbox housing;
b - protrusion of the tapered roller bearing of the secondary shaft from the gearbox housing;
c - drowning of the supporting surface of the rear bearing of the secondary shaft in the rear cover of the gearbox;
d - drowning of the bearing surface of the rear bearing of the input shaft in the rear cover of the gearbox;
s is the thickness of the adjusting ring of the rear bearing of the secondary shaft;
v is the thickness of the adjusting ring of the input shaft rear bearing;
e is the thickness of the gasket.
Determine dimensions with a depth gauge «A», «b», «With» And «d».
Scheme of selection of adjusting rings when installing the rear bearings of the primary and secondary shafts in the rear crumb of the gearbox:
a - protrusion of the rear bearing of the input shaft;
b - protrusion of the rear bearing of the secondary shaft;
c - drowning of the bearing surface of the rear bearing of the secondary shaft;
d - sinking of the bearing surface of the input shaft rear bearing;
e is the thickness of the gasket;
v - thickness of the adjusting sharp rear bearing of the input shaft;
s is the thickness of the adjusting ring of the rear bearing of the secondary shaft.
The input shaft bearing of some gearboxes is combined (rollerball). In this case, a sealing gasket with a thickness of 0.40 mm is installed, and the adjustment of the axial movement of the bearings is carried out by selecting the thickness of the adjusting rings installed under the bearings of the primary and secondary shafts.
On other gearboxes, the necessary protrusion of the input shaft rear bearing is provided by installing a sealing gasket with a thickness of 0.30 or 0.40 mm.
The rear bearings of the primary and secondary shafts are installed with a preload of 0.10 mm, provided by compressing the gasket. On a gearbox with a ball bearing on the input shaft, the thickness of the gasket is selected based on the size «A». If size «A» is 0.20-0.26 mm, a gasket with a thickness of 0.30 mm should be installed. If size «A» is in the range of 0.27-0.42 mm, it is necessary to install a gasket with a thickness of 0.40 mm. On a gearbox with a combined input shaft bearing, the gasket thickness is constant and equal to 0.40 mm.
Calculate the thickness of the adjusting rings using the formulas:
s=c-b+0.3,
v=d-a+0.4.
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