Rear axles RT2610HV / RT3210HV Design and Function Student booklet
Rear axles RT2610HV/RT3210HV
Contents
This training package describes the rear axle’s design and function. Service operations and the use of special tools are described in Volvo’s service literature.
2 Type plate ............................................5
1 General, tandem rear axle ....................3
3 Tandem rear axle ..................................6 4 Final drives, front/rear ...........................7 5 Gear set, front/rear ...............................8 6 Pinion bearings, front and rear ............. 9 7 Pinion shims, front and rear .................. 10 8 Input shaft shims, transfer gear .............11 9 Differential ...........................................12 10 Transfer gear ......................................13 11 Transfer gear differentiallock...............14 12 Wheel differentiallock .........................15 13 Drive shafts ........................................16 14 Wheel bearings ..................................17 15 Hub reduction .....................................18 16 Maintenance ...................................... 19
Aftermarket Training Rear axles RT2610HV & RT3210HV
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Student Booklet
1 General, tandem rear axle RT2610HV/RT3210HV are identical in design and function. The difference is max bogie pressure and that RT3210HV is designed for Volvo FM construction vehicles. This are two tandem rear axles that consists of two single reduction gears of spiral bevel type and a transfer gear that is fitted to the first rear final drive. This rear axle is intended for use in heavy and demanding haulage operations both on good roads and on poor road conditions. Drive to two axles means that extremely high traction can be transferred to the road surface, since the total axle pressure is high. This promotes excellent getyou-there ability, and also results in more uniform tyre wear between the front and rear axles. RT26/3210HV is equipped with three differential locks, one each for the front and rear axle, and one for the transfer gear. This guarantees excellent traction when the road surface is slippery and offers poor grip. RT2610HV or RT3210HV is the type designation of this tandem rear axle. R = Rear axle T = Tandem 26/32 = Max bogie pressure 26.000kg/32,000kg 100 = Max gross combination weight 100,000kg H = Hub reduction V = Volvo
Aftermarket Training Rear axles RT2610HV & RT3210HV
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Student Booklet
Specifications: Make Type designation
Volvo RT2610HV or RT3210HV
Type: Final drive Transfer gear Hub reduction Crown wheel, diameter Driveshafts, diameter Max engine torque Max bogie pressure Max gross combination weight
Single reduction, spiral bevel, hub reduction Cylindrical gear Cylindrical planetary gear 295 mm 45 mm 3100 Nm 26.000kg or 32,000 kg 100,000 kg
Weight including driveshafts, hubs and drum brakes: Front axle RT2610HV/RT3210HV 861/879 kg Rear axle RT2610HV/RT3210HV 758/776 kg Weight including driveshafts, hubs and disc brakes: Front axle RT2610HV 816 kg Rear axle RT2610HV 730 kg Oil-change volumes: Front final drive,RT2610HV/RT3210HV Rear final drive, RT2610HV/RT3210HV Each hub (included in above values)
29/31 litres. 26/26 litres. 1,5- 3 litres depending on versions of hub casing.
Ratios : 3.61:1, 3.76:1, 4.12:1, 4.55:1, 5.41:1 and 7,21:1 only for RT3210HV. The transfer gear has a ratio of 1:1.
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Aftermarket Training Rear axles RT2610HV & RT3210HV
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2 Type plate The rear axles are made by Volvo and the type designations are RT2610HV/RT3210HV. The type plate consists of the following markings: COMPONENT = component designation DIFF. CARRIER/RATIO= final drive/ratio SERVICE CATEGORY = service category PART NO REAR AXLE = Volvo’s part number DIFF. ASSY = Volvo’s part number FABR. NO DIFF. ASSY = date of manufacture ID = Internal factory number ............................................................................................................................................................... ............................................................................................................................................................... .............................................................................................................................................................. ................................................................................................................................................................ ............................................................................................................................................................... ............................................................................................................................................................... .............................................................................................................................................................. ................................................................................................................................................................ ............................................................................................................................................................... ............................................................................................................................................................... .............................................................................................................................................................. ................................................................................................................................................................
Aftermarket Training Rear axles RT2610HV & RT3210HV
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Student Booklet
3 Tandem rear axle Tandem rear axles RT2610HV/RT3210HV consists of two rear axles of the following main components; The first rear axle consists of: 1. Rear axle casing 2. Final drive with transfer gear 3. Differential locks (transfer gear, differentiallock and wheel differentiallock). 4. Driveshafts 5. Output shaft The second rear axle consists of: 6. Rear axle casing 7. Final drive 8. Wheel differential lock 9. Driveshafts ............................................................................................................................................................... ............................................................................................................................................................... .............................................................................................................................................................. ................................................................................................................................................................ ............................................................................................................................................................... ............................................................................................................................................................... .............................................................................................................................................................. ................................................................................................................................................................
Aftermarket Training Rear axles RT2610HV & RT3210HV
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4 Final drives, front/rear Both the final drives (gear sets) are of spiral bevel type, which means that the pinion’s centre line is in line with the crown wheel’s centre line. Due to that the ratio is small, the differencies in diameter between the crownwheel/pinion are small. This gives a compact and service friendly final drive with small internal losses.
The crown wheel and pinion are matched to each other and cannot be replaced individually, but only as a complete pair. In order to avoid the risk of accidentally separating the gear set, the crown wheel and pinion are both marked with the same serial number. The front final drive consists of; gear set, transfer gear, differential, transfer gear differentiallock and wheel differentiallock. The rear final drive consists of; gear set, differential and wheel differentiallock. ............................................................................................................................................................... ............................................................................................................................................................... .............................................................................................................................................................. ................................................................................................................................................................ ............................................................................................................................................................... ............................................................................................................................................................... .............................................................................................................................................................. ................................................................................................................................................................ ............................................................................................................................................................... Aftermarket Training Rear axles RT2610HV & RT3210HV
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5 Gear set, front/rear The gear set consists of the pinion and crown wheel. The crown wheel is attached to the differential. A: The front pinion is supported by two conical roller-bearings. B: The rear pinion is also supported by two conical roller-bearings. Adjustment of the pinion’s axial position is done with shims between the inner bearing’s outer ring and the final drive housing. The correct pinions pre-tension is achieved with spacer sleeves in both final drives.
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Aftermarket Training Rear axles RT2610HV & RT3210HV
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6 Pinion bearings, front and rear Both the front and rear pinion is supported by two conical roller-bearings, A and B in the picture. Spacer sleeve C in the picture is used to create the correct pre-tension for the pinion bearings. Adjustment of the pinion’s axial position is done with shims between the inner bearing’s outer ring and the final drive housing.
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Aftermarket Training Rear axles RT2610HV & RT3210HV
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7 Pinion shims, front and rear Adjustment of the pinion’s axial position is done with shims between the inner bearing’s outer ring and the final drive housing, A in the picture. Both pinions are supported by two conical roller-bearings.
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Aftermarket Training Rear axles RT2610HV & RT3210HV
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8 Input shaft shims, transfer gear Axial play for the transfer gears input shaft is achieved with shims, between the cover and the final drive housing.
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Aftermarket Training Rear axles RT2610HV & RT3210HV
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9 Differential The purpose of the differential is to distribute torque and speed between the driven wheels and at the same time maintain overall tractive power. This is necessary since the outer wheel has a longer distance to travel in a curve than the inner wheel. The outer wheel must therefore rotate faster than the inner wheel. The differential is fitted in the differential housing and consists of four small conical gears, differential gears that are fitted to the spider. Two counter-rotating larger conical differential gears mesh with the four small gears, each linked with its respective driveshaft. When the vehicle is driving straight ahead, the small gears in the differential are at a standstill and both the driven wheels rotate at the same speed. When taking a curve, when the inner wheel rotates more slowly, the small wheels start rotating on the spider. Through this rotation, the speed reduction of the inner wheel is taken up and transferred to the outer wheel, which responds with a corresponding increase in speed. The differential is supported with two conical bearings. The purpose of the adjustment screws is to create the correct pre-tension on the differential bearings and to give the gear set the correct tooth flank clearance. ............................................................................................................................................................... ............................................................................................................................................................... .............................................................................................................................................................. ................................................................................................................................................................ ............................................................................................................................................................... ............................................................................................................................................................... .............................................................................................................................................................. Aftermarket Training Rear axles RT2610HV & RT3210HV
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10 Transfer gear The forward final drive is equipped with a transfer gear. It has the task of distributing drive between the two rear axles. Power from the gearbox goes from the transfer gear’s input shaft via the transfer gear’s differential to the output shaft which drives the second rear axle via a short propeller shaft. Power to the first rear axle goes via a cylindrical gear. The path of the power: pinion, crown wheel, differential spider, via the small differential gears, on to the large differential gears and then to the driveshafts, before finally going to the wheels.
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Aftermarket Training Rear axles RT2610HV & RT3210HV
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Student Booklet
11 Transfer gear differentiallock he transfer gear is equipped with a differential lock to permit the same rotation speed on the rear axles. The differential lock is operated via a two-stage switch on the instrument panel. When the switch is pressed to its first position, the transfer gear differential lock is engaged, linking the two rear axles to each other. A symbol comes on in the instrument panel to indicate when the transfer gear differential lock is activated.
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Aftermarket Training Rear axles RT2610HV & RT3210HV
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Student Booklet
12 Wheel differentiallock Each rear axle has a wheel differential lock on the right driveshaft to ensure the same rotation speed for the driveshafts on each respective rear axle. When one wheel slips, for instance on a slippery road surface, it is possible to disengage the differential by linking the driveshafts to each other with a differential lock, locking one driveshaft to the differential housing. When the wheel differential lock is engaged, a symbol appears in the instrument panel. The locks consist of a claw coupling made of hardened steel which is manoeuvred by compressed air. When all the differential locks are engaged, all the driven wheels are forced to rotate at the same speed.
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Aftermarket Training Rear axles RT2610HV & RT3210HV
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Student Booklet
13 Drive shafts The driveshafts are of the fully unloaded type, that is to say the axles do not carry any of the vehicle’s weight; instead, their only job is to transfer rotating movement/torque from the final drive to the driven wheels. The inner ends of the driveshafts are equipped with splines for linking up to the large differential gears in the final drive. The outer ends feature a flange for fitting to the hub. In addition, the rightside driveshaft is equipped with an additional set of splines for the wheel differential lock’s connecting flange.
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Aftermarket Training Rear axles RT2610HV & RT3210HV
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Student Booklet
14 Wheel bearings The wheel bearings are maintenance-free unit bearings. They consist of conical roller-bearings that are lubricated for life from the factory and fitted with sturdy seals. The wheel hub and its bearing are fitted and removed as a single unit, which makes the process much more convenient. Bearing play is checked by inserting a metal bar in the wheel’s lightening holes and using the bar as a lever. Normally, the bearings should be pre-tensioned, so there should not be any measurable play in the wheel bearing. If any play is registered in the bearing, it should be measured with a dial gauge. NOTE: The bearing clearance cannot be adjusted. ............................................................................................................................................................... ............................................................................................................................................................... .............................................................................................................................................................. ................................................................................................................................................................ ............................................................................................................................................................... ............................................................................................................................................................... .............................................................................................................................................................. ................................................................................................................................................................ ............................................................................................................................................................... ............................................................................................................................................................... .............................................................................................................................................................. ................................................................................................................................................................
Aftermarket Training Rear axles RT2610HV & RT3210HV
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Student Booklet
15 Hub reduction The hub reduction, which is located in the wheel hub, is where the majority of the torque conversion occurs. The hub reduction consists of a cylindrical planetary gear with straight needle bearing gears that produce little loss. The sun gear is mounted on the driveshaft and from here the driving power is transferred to the planetary gear, which is connected to the wheel hub. When the planetary gear is forced to rotate towards the ring gear, which is locked to the rear axle housing, there is a reduction in engine speed. This type of rear axle combination with tandem drive allows for considerable propulsion to be transferred to the ground without spinning wheels, since there is a great deal of combined axle pressure. This makes navigation very easy and reduces tyre wear. NOTE: The oil level plug in the picture is in the drain position. When checking the oil level the hole shall be in the horizontal position. Oil up to the hole edge when the level is correct. ............................................................................................................................................................... ............................................................................................................................................................... .............................................................................................................................................................. ................................................................................................................................................................ ............................................................................................................................................................... ............................................................................................................................................................... .............................................................................................................................................................. ................................................................................................................................................................ ............................................................................................................................................................... Aftermarket Training Rear axles RT2610HV & RT3210HV
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Pr ev en tiv e
Se rv ice M Bu anua ss l Gr es Ve ou rsi p 17 M on ai nt 01 en an ce
Service Information
16 Maintenance The rear axle has long service intervals that contribute to low operating costs. With Volvo-approved synthetic oil, oil is changed after max 400,000 km or every three years.
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Aftermarket Training Rear axles RT2610HV & RT3210HV
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Student Booklet
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