Slides. Rear Axle RTS2370A. Texto[1]

Rear axle RTS2370A Design and Function Student booklet

RTS2370A

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.

1 General, tandem rear axle RTS2370A ...... 3 2 Type plate .................................................. 5 3 Tandem rear axle RTS2370A .................... 6 4 Final drives, front/rear................................ 7 5 Gear sets, front/rear .................................. 8 6 Differential ................................................. 9 7 Transfer gear ........................................... .. 10 8 Transfer gear differential lock .................... 11 9 Wheel differentiallock ................................ 12 10 Driveshafts .............................................. 13 11 Wheel bearings ....................................... 14 12 Maintenance ............................................ 15

Aftermarket Training GT140001A

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1. General, tandem rear axle RTS2370A RTS2370A is a tandem rear axle that consists of two single reduction gears of hypoid 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. RTS2370A 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. RTS2370A is the type designation of this tandem rear axle. R = Rear axle T = Tandem S = Single reduction gear 23 = Max bogie pressure 23,000kg 70 = Max gross combination weight 70,000kg A = Version


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Specifications: Make Type designation Type: Final drive Transfer gear Crown wheel, diameter Driveshafts, diameter Max engine torque Max bogie pressure Max gross combination weight

Meritor RTS2370A Single reduction, Hypoid type, DTS35A front, DSS35A rear Cylindrical gear 401-417mm 53 mm 3100 Nm 23,000 kg 70,000 kg

PAGE 4. Weight including driveshafts, hubs and drum brakes (with leaf springs): Front axle 793 kg Rear axle 694 kg Weight including driveshafts, hubs and disc brakes (with air suspension): Front axle 751 kg Rear axle 639 kg Oil-change volume: Front axle Rear axle

20 litres 14 litres

Ratios : 2.43:1, 2.57:1, 2.83:1, 3.09:1, 3.40:1, 3.78:1, 4.13:1, 4.50:1, 5.14:1, (5.67:1. production start 0335 for the FL6) The transfer gear has a ratio of 1:1.

Notes: ............................................................................................................................................................... ............................................................................................................................................................... .............................................................................................................................................................. ................................................................................................................................................................ ............................................................................................................................................................... ............................................................................................................................................................... ............................................................................................................................................................... ................................................................................................................................................................. ............................................................................................................................................................... ................................................................................................................................................................ ............................................................................................................................................................... ................................................................................................................................................................ ................................................................................................................................................................ ..................................................................................................................................................................


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2. Type plate The rear axle is made by Meritor and is designated RTS2370A. 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

Notes: ............................................................................................................................................................... ............................................................................................................................................................... .............................................................................................................................................................. ................................................................................................................................................................ ............................................................................................................................................................... ............................................................................................................................................................... ............................................................................................................................................................... ................................................................................................................................................................. ...............................................................................................................................................................


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3. Tandem rear axle RTS2370A Tandem rear axle RTS2370A consists of two rear axles with 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, differential lock and wheel differential lock). 4. Driveshafts 5. Output shaft The second rear axle consists of: 6. Rear axle casing 7. Final drive 8. Wheel differential lock 9. Driveshafts The rear axle casings are cast in nodular iron. Notes: ............................................................................................................................................................... ............................................................................................................................................................... .............................................................................................................................................................. ................................................................................................................................................................ ...............................................................................................................................................................


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4. Final drives, front/rear Both the final drives (gear sets) are of hypoid type, which means that the pinion’s centre line is offset in relation to the crown wheel’s centre line. This design allows more gear teeth to be in mesh at the same time, thus distributing the power over several teeth. The result is a strong gear characterised by quiet operation and high dependability. 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 relevant components: The front final drive consists of: gear set, transfer gear, differential, transfer gear differential lock, wheel differential lock. The rear final drive consists of: gear set, differential, wheel differential lock. Notes: ............................................................................................................................................................... ............................................................................................................................................................... .............................................................................................................................................................. ................................................................................................................................................................ ............................................................................................................................................................... ...............................................................................................................................................................


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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. Adjustment of the pinion’s position is done with shims between the inner bearing’s outer ring and the final drive housing. B: The front pinion is supported in the pinion bearing sleeve (consisting of two conical rollerbearings). The bearings are pre-fitted and cannot be replaced separately since they are unit bearings. Behind the pinion gear there is also a roller-bearing to handle radial forces. Adjustment of this pinion’s position is also done with shims, between the pinion bearing sleeve and the final drive housing. The correct pinion pre-tension is achieved as follows: Front pinion: with spacer sleeve and correct tightening torque. Rear pinion: correct tightening torque for the pinion nut. Correct pre-tension on the rear pinion owing to the unit bearing = checked and fixed. Notes: ............................................................................................................................................................... ............................................................................................................................................................... .............................................................................................................................................................. ................................................................................................................................................................


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6. 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. Notes: ............................................................................................................................................................... ............................................................................................................................................................... .............................................................................................................................................................. ................................................................................................................................................................


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7. Transfer gear 1. Input shaft 2. The transfer gear’s differential

3. Output shaft 4. Cylindrical 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 wheel.

Anteckningar: ............................................................................................................................................................... ............................................................................................................................................................... .............................................................................................................................................................. ................................................................................................................................................................ ............................................................................................................................................................. ............................................................................................................................................................... .............................................................................................................................................................. ................................................................................................................................................................


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8. Transfer gear, differential lock The 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.

Notes: ............................................................................................................................................................... ............................................................................................................................................................... .............................................................................................................................................................. ................................................................................................................................................................ .............................................................................................................................................................. ................................................................................................................................................................ ............................................................................................................................................................... .............................................................................................................................................................. ................................................................................................................................................................ ............................................................................................................................................................... .............................................................................................................................................................. ................................................................................................................................................................


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9. Wheel, differential lock 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.

Notes: ............................................................................................................................................................... ............................................................................................................................................................... .............................................................................................................................................................. ................................................................................................................................................................ ............................................................................................................................................................... .............................................................................................................................................................. ................................................................................................................................................................ ............................................................................................................................................................... .............................................................................................................................................................. ................................................................................................................................................................


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10. Driveshafts 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. The driveshafts for the first and second rear axle are of different lengths; do n´t mix them during installation. Notes: ............................................................................................................................................................... ............................................................................................................................................................... .............................................................................................................................................................. ................................................................................................................................................................ ............................................................................................................................................................... ............................................................................................................................................................... ............................................................................................................................................................... ................................................................................................................................................................. ............................................................................................................................................................... ..............................................................................................................................................................


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11. 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.

Notes: ............................................................................................................................................................... ............................................................................................................................................................... .............................................................................................................................................................. ................................................................................................................................................................ ............................................................................................................................................................... ............................................................................................................................................................... ............................................................................................................................................................... ................................................................................................................................................................. ............................................................................................................................................................... ................................................................................................................................................................


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12. 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. When overhauling follow the instructions i service bulletins; SB 465-73, front final drive SB 465-78, rear final drive At service, check the sealing around the rear axle housing – pay special attention to any signs of leakage. Notes: ............................................................................................................................................................... ............................................................................................................................................................... .............................................................................................................................................................. ................................................................................................................................................................ ............................................................................................................................................................... ............................................................................................................................................................... ............................................................................................................................................................... ................................................................................................................................................................. ............................................................................................................................................................... ................................................................................................................................................................ ............................................................................................................................................................... ................................................................................................................................................................


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Volvo Truck Coporation Aftermarket Training © Copyright 2002 Volvo Truck Corporation

Slides. Rear Axle RTS2370A. Texto[1]

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