The steering mechanism with built-in hydraulic booster works as follows. When the car moves in a straight line, screw 4 (Fig. 1) and spool 8 are in the middle position.

Injection lines A and drain B, as well as both cavities C and D of the hydraulic cylinder are interconnected.

Scheme of the Kamaz steering

Oil passes freely from pump 11 through the control valve and returns to the tank.

The resistance that occurs when the wheels are turned by means of the steering drive creates a force that tends to move the screw in the axial direction in the corresponding direction.

When this force exceeds the precompression force of the centering springs 9, the screw displaces the spool rigidly connected to it.

In this case, one cavity of the hydraulic booster cylinder communicates with the discharge line and is disconnected from the drain line, and the other, remaining connected to the drain line, is disconnected from the discharge line.

The working fluid coming from the pump into the corresponding cavity of the cylinder puts pressure on the piston rack 2 and, by creating additional force on the toothed sector of the shaft 1 of the steering mechanism bipod, contributes to the rotation of the steered wheels.

The pressure in the working cavity of the booster cylinder increases to a value proportional to the resistance to turning the wheels.

At the same time, the pressure in the cavities under the jet plungers increases.

When the resistance to turning the wheels changes, and consequently, the pressure in the working cavity of the cylinder, the force with which the spool seeks to return to the middle position and the force on the steering wheel change, which provides the driver with a “sense of the road”.

Kamaz car steering rod parts

When the steering wheel stops turning, the spool, under the action of centering springs and increasing pressure in the reactive cavities, shifts to the middle position so that a slot opens for the passage of oil supplied by the pump to the drain line.

The size of the gap is set so that the pressurized cavity of the cylinder maintains the pressure necessary to keep the steered wheels in the turned position.

If the front wheel begins to turn sharply while the vehicle is moving in a straight line, for example, when hitting an obstacle, the bipod shaft, turning, will move the piston rack.

Since the screw does not rotate (the driver holds the steering wheel in one position), it will also move axially along with the spool.

In this case, the cylinder cavity, inside which the piston-rack moves, will be connected to the pump discharge line and separated from the drain line.

The pressure in this cavity of the cylinder rises, which balances (softens) the blow.

When the hydraulic booster is not working, the steering mechanism still turns the wheels, but the parts are already under full load. At the same time, the wear of parts increases sharply and their breakdowns are possible.

The steering gear includes longitudinal and transverse steering rods (Fig. 2.).

Longitudinal rod connects the bipod of the steering mechanism with the upper arm of the left steering knuckle and is made with non-adjustable hinges.

Hinges include ball pin 22, upper 23 and lower 24 liners, spring and threaded cap 27 with lock washer 26.

The tie rod of the steering trapezoid is tubular, with threaded ends, on which tips with ball joints are screwed.

Toe-in of the steered wheels is adjusted by turning the rod in the tips. Each tip is fixed with two bolts 32.

The transverse link joints are also non-adjustable, they consist of a ball pin 7, upper 8 and lower 6 liners, a spring 5 and a cover 3 fixed through a sealing paronite gasket 4 on the rod tip.

To prevent dust and dirt from getting into them, rubber protective pads are used.

Hinges are lubricated through grease fittings.

In the steering gear of vehicles with a 6X6 wheel arrangement, the tie rod is bent so that its middle part moves freely under the main gear housing of the front drive axle.

Therefore, the toe-in of the front wheels on these cars is regulated by moving the tips on the rod, unscrewing the bolts 32 and rotating the tips on the thread, taking into account that the thread pitch on the left and right tips is different.