Scheme of the middle bridge KamAZ 6520

Rice. 451 Middle axle KamAZ 6520 : 1 – wheel reducer; 2 – wheel hub; 3 – brake drum; 4 – brake mechanisms; 5 – axle housing; 6 – left axle shaft; 7 – main gear of the rear axle; 8 – rear axle drive gear; 9 - right axle shaft; 10 – rear axle drive shaft; 11 – ball bearing; 12 – bearing cover; 13 – output flange

Central main gear of the KamAZ 6520 middle axle

The drive bevel gear 13 is mounted on two bevel bearings 15 and 19, located in a cup 16, secured with self-locking bolts to the gear housing 14 of the middle axle. Between the end surfaces of the gearbox housing 14 and the flange part of the cup 16, adjusting shims 17 are installed. Between the inner rings of bearings 15 and 19 there is an adjusting sleeve 18. A driven spur gear 20 is installed on the splined end of the gear 13, which is tightened with a self-locking nut 21 and is driven into rotation by the drive spur gear. gear 1, made together with the bevel gear ring of the middle axle drive and located on two radial roller bearings 2 and 22, installed in the gearbox housing 14 of the middle axle.

The driven bevel gear is pressed onto the differential cup and secured to it using self-locking bolts.

Adjustment of the engagement of the bevel gears is carried out by adjusting shims 17 and adjusting nuts 12. The preload of the bevel bearings 15 and 19 in the drive gear assembly is carried out by selecting the linear dimensions of the adjusting sleeve 18, and the bevel bearings 11 of the differential - by adjusting nuts 12. The through drive shaft 27 is supported by one the end on the radial roller bearing 11, located in the bevel gear 10 of the rear axle drive, and the other on the tapered roller bearing 24, the outer ring of which is pressed into the bearing cover 25. To adjust the tapered bearings, an adjustment package is provided between the bearing cover 25 and the gear housing 14 of the middle axle gaskets 23. The center differential crosspiece 4 is installed on the inner splined part of the drive shaft 27, and the middle axle drive flange 26 is installed on the outer splined end. The rear axle drive shaft is installed at one end in the splined hole of the bevel gear of the center differential, and at the other end it rests on a radial ball bearing located in a special cup of the axle housing cover. A rear axle drive flange is installed on the outer splined end of the shaft.

Adjusting the main KAMAZ transmission

The repaired crankcase needs to be adjusted after installation on the car. In the KAMAZ crankcase, the following mechanisms and values are regulated: preload of the bearings of the driven and driving bevel gears, differential, lateral clearance, as well as the contact patch of the bevel pair.

To adjust the preload in the bevel bearings of the drive gear, proceed as follows:

reduce the total thickness of the pack of adjusting washers by the amount of axial movement plus 0.04-0.06 mm. To do this, you can grind or replace one washer;
with a torque of 240-360 N (24-36 kgf), tighten the nut securing the bevel wheel flange; Next, you need to check the rotation force of the bearing cup. It should be 11.4-22.8 N, or 1.14-2.28 kgf.
The measurement must be carried out with continuous rotation of the bearing in one direction (at least 5 full revolutions).

If the obtained values differ from the required data, repeat the adjustment.

Adjustment of the preload in the bevel bearings of the driven gear must be done as follows:

in the same way as in the first case, reduce the total thickness of the adjusting washers by the amount of axial movement plus 0.03-0.05 mm. This can be done either by grinding the washers, or by installing others with the desired size;
Tighten the driven bevel gear bearing nut. The moment should be 350-400 N (35-40 kgf);
check the rotation force of the bearing cup. It can fluctuate in the range of 14.3-50 N (1.43-5 kgf). This procedure is performed in the same way as when adjusting the tension in the bevel bearings of the drive gear.

If the obtained data is lower or higher than the required values, repeat the adjustment.

After you have adjusted the tension in the bearings of the drive and driven wheels, install them in the gear housing and begin adjusting the side clearance. To do this, you will need shims of various thicknesses. The gap should be 0.20-0.35 mm.

To adjust the differential, it is necessary to install it so that the ring gear of the driven wheel is completely symmetrical to the ring gear of the driving cylindrical wheel. Then tighten the bolts (the torque should be 100-120 N or 10-12 kgf) and proceed directly to the adjustment:

tighten the adjusting nuts evenly on both sides until the distance between the bearing covers increases by 0.10–0.20 mm;
tighten the cover bolts with a torque of 250-320 N (25-30 kgf) and lock them.

Central main gear of the KamAZ 6520 middle axle

The central main gear of the KamAZ 6520 middle axle (Fig. 453) is a straight-through, single-stage, with a center differential, contains a pair of bevel gears with spiral teeth, intermediate cylindrical helical gears, a cross-axle differential and a middle axle gear housing.
The drive bevel gear 13 is mounted on two bevel bearings 15 and 19, located in a cup 16, secured with self-locking bolts to the gear housing 14 of the middle axle. Between the end surfaces of the gearbox housing 14 and the flange part of the cup 16, adjusting shims 17 are installed. Between the inner rings of bearings 15 and 19 there is an adjusting sleeve 18. A driven spur gear 20 is installed on the splined end of the gear 13, which is tightened with a self-locking nut 21 and is driven into rotation by the drive spur gear. gear 1, made together with the bevel gear ring of the middle axle drive and located on two radial roller bearings 2 and 22, installed in the gearbox housing 14 of the middle axle.

The driven bevel gear is pressed onto the differential cup and secured to it using self-locking bolts.

Rice. 453 Main transmission of the middle axle: 1 - driving cylindrical helical gear; 2, 9 and 22 - radial roller bearings; 3 and 7 — cups of the center differential; 4 — crosspiece of the center differential; 5 — support washers of the satellites of the center differential; 6 — satellite center differential; 8, 15, 11, 19 and 24 - tapered roller bearings; 10 — bevel gear wheel of the rear axle drive; 12 — adjusting nut of differential bearings; 13 — driving conical wheel; 14 — middle axle gear housing; 16 — cup of bearings; 17 and 23 — shims; 18 — adjusting sleeve; 20 — driven cylindrical wheel; 21 - nut; 25 — bearing cover; 26 — drive flange; 27 — drive shaft; 28 — retaining ring; 29 — lock washer; 30 — differential bearing cover mounting bolt, 31 — lock washer.

Gearbox KAMAZ 43118

The KAMAZ 43118 gearbox is available in versions with 49 to 50 teeth for an axle shaft with 20 splines. The presence of an ICD block allows the car to overcome any obstacles. The price for this transmission of the middle and rear axle is indicated in our catalog:

New sections with useful materials
Documentation and operation
The design of the KamAZ 43118 gearbox does not differ significantly from other mechanisms of this type. Although a large number of these units are now being produced, many of them are unified and can be used on different trucks of the Kama Automobile Plant.

For the front drive axle, a part from KamAZ 43114 is successfully used as a gearbox on KamAZ 43118. A gearbox from the same vehicle is also suitable for the middle axle. You can also use components installed on trucks without front-wheel drive (KAMAZ 65115, 65117 and others). As a gearbox for the rear axle of KamAZ 43118, main gear mechanisms of the entire line of Eurostandard vehicles are used, equipped with a cross-axle differential lock.

Structurally, these units were designed very well, so they did not undergo major changes. Over the years of operation, they have proven themselves to be reliable and unpretentious in operation.

The KamAZ 43118 gearbox transforms engine rotation, reducing its frequency and, accordingly, increasing power. It includes elements of the main gear and cross-axle differential. The design of the main gear allows the axle axis to be set at 90 degrees relative to the driveshaft.

The KamAZ 43118 gearbox consists of a housing in which the moving parts of the mechanism are located. The drive shafts of the front and rear axles have a flange at one end for connecting the crankshaft. The middle axle is equipped with a shaft with flanges at both ends for connection to the center differential. A small bevel gear is installed on the splines of the drive shaft; it is also the drive gear. The large bevel gear is located on the intermediate shaft, along with the drive spur gear. The large spur gear (driven) does not have its own shaft and is assembled as one unit with an inter-wheel differential. The inter-wheel differential mechanism, mounted in the KamAZ 43118 gearbox, acts as a distribution of torque between the wheels. It consists of two bowls connected to a large spur gear. Inside this structure there is a cross with satellites at the ends and two semi-axial gears. The narrow part of the differential bowls is equipped with roller bearings.

When the road turns, when the wheels on one side of the car travel a greater distance than the other, the differential begins to work. The satellites begin to rotate around their axis, and increase the speed of one side gear, slowing down the other. The axle shafts that engage with them rotate at the same frequency, then the torque is transmitted to the wheels.

The KamAZ 43118 gearbox is equipped with a differential lock system. To do this, its left cup is made with splines on which a locking clutch is installed. In slippery or wet dirt road conditions, the wheels may slip, and the vehicle's maneuverability is reduced. When the lock is turned on, both axle shafts rotate at the same speed, and slipping is eliminated.

The KamAZ 43118 truck is designed to work in difficult road conditions, so good traction characteristics are important for it. For this purpose, the KamAZ 43118 axle gearbox has a gear ratio of 6.53 or 7.22. This corresponds to the use of a large spur gear with 49 or 50 teeth. The gearbox housing is attached to the central part of the middle and rear axles. In the front drive axle it is shifted to the left from the middle. 7 liters of transmission oil are poured into the crankcase cavity through a special hole to lubricate the bearings and rubbing surfaces of the mechanism. The hole is closed with a plug. There is a drain hole at the bottom for replacing used oil.