Power steering, or power steering - just a necessity for heavy and heavy cars. And if on cars, many do without this assistant, then try to turn the steering wheel of the Kamaz without it. Today we will all learn about the Kamaz GUR: the arrangement of mechanisms, the principle of operation, and we’ll also talk about typical malfunctions and repair.
Tasks that GUR solves
The main goal of the power steering is to lighten as much as possible the force needed to turn the steering wheel in case of performing various maneuvers at low speeds.
Also, the amplifier makes the steering effect more noticeable at high speed.
Device
What is the Kamaz power steering device? The mechanism consists of a distributor, hydraulic cylinder, hydraulic fluid, pump, as well as connectors and an electronic control unit.
A distributor is required to direct the flow of hydraulic fluids into the system cavity. The hydraulic cylinder solves the problem of converting hydraulic pressure into the mechanical work of rods and pistons. The fluid not only transfers forces from the pump to the hydraulic cylinder, but also lubricates the friction units and parts. His pump is designed to constantly maintain the necessary pressure. It also promotes fluid circulation. The connector or tube GUR "KamAZ" is used to combine among themselves all the elements of this design. And finally, the electronic unit. It directs and regulates the operation of the amplifier.
Typical GUR device
What is the power steering ("KamAZ") device? Often actuators are presented in a single housing with the steering system. Such an amplifier can be called integral. As a hydraulic fluid, various ATF oils are used. These are usually poured into FRGG.
How does he work? At GUR "KamAZ" the scheme of work is very simple. When the steering wheel is rotated, the rotary or axial piston pump, which is driven by the crankshaft belt, will start pumping oil from the tank and then pump hydraulic fluid at a sufficiently high pressure into the spool type distributor. The latter tracks the force exerted on the steering wheel and assists in turning the wheels. To do this, use a special tracking device. Often such an element in typical systems is the torsion bar. It is built into the section of the steering shafts.
If the car is standing or moving in a straight path, then there is no force on the steering shaft. Accordingly, the torsion bar is open, and the valves of the distributor are closed. Oil in this case is dumped into a tank. When the steering wheel is fixed, the torsion bar is twisted. The spool releases the channels, and the working fluid is directed to the actuator.
If the system is equipped with a rack and pinion mechanism, then the liquid is supplied directly to the rack housing. When the steering wheel is turned all the way, safety valves are included in the case, which relieve pressure in time and protect the mechanical components from possible damage.
Power steering "KamAZ-5320"
Its device is practically no different from a standard amplifier. Here, too, there is a distributor, gearbox, as well as a hydraulic cylinder built into the steering.
The operation of this unit is possible only with constant movement of the working fluid. This ensures a low load on the pump. The pressure in the system is 8000 kPa. The power cylinder is integrated into the steering gear housing. As a control valve, a spool valve is used, equipped with a system of reactive plungers and centering springs. They create a feeling of resistance at the moment of turning the wheels.
Power steering "KamAZ-4310"
This unit is almost completely the same as in the model 5320. The principle of operation of the Kamaz-4310 power steering, the device and the design of this unit are practically no different. The main difference is only in the reinforcement of some parts, as well as in the modified fastening of the steering bipod. Here, the bolts, cotter pins and other fasteners are now replaced with nuts with lock washers.
Hydraulic pump
The power steering pump is mounted in the collapse of the cylinder block.
At KAMAZ, a gear type drive is used, however, the pump belongs to a blade type. It has a double action. In one full revolution, he performs two cycles of injection and suction.
Device
What device does the Kamaz power steering pump have? This assembly consists of housing parts, a stator and a rotor, which is equipped with blades. Also, a shaft with bearings and gear for driving is used in the design. In addition to the pump, the design has a distribution disc, as well as bypass and safety valves. There is also a tank, filter and manifold.
Housing parts, the stator, as well as the cover are connected and fastened with four bolts. The housing has a cavity where suction oil enters. At the end of it you can find two oval-shaped holes. Through them, hydraulic fluid is supplied to the rotor. The lid has a special bore for the distribution disc, valve openings, as well as a channel. There is a calibration hole in the bottom of the lid.
The rotor is mounted in the stator using slots. The blades are placed in its grooves. The shaft can rotate with ball bearings. The fluid is directed to the blades using a distribution disk. By means of a spring, the disk is pressed tightly against the stator and the rotor. The bypass valve then limits the operation of the pump, and the safety element holds back the pressure created by the pump.
There is also a special tank for liquid. It is mounted on the pump housing. There is a special strainer in the tank. Here you can find both the inlet filter and the safety valve.
How does the pump work?
When the rotor blades rotate, then when inertia is applied, they are pressed against the stator. In the blades, which coincide with the holes in the housing, as well as the distribution disk, fluid is supplied. Then it is pumped using the blades into a narrower part between the rotor and the stator. When the working cavities coincide with the holes in the disk, the liquid will escape through the holes for the disk. And from there, under high pressure, it will go through the lower valve into the system. Oil from the cavity behind the disk enters the rotor blades and presses them even more against the stator surface.
Injection and suction work at one moment in two places at once. When the rotational speed of the rotor increases, the oil from the cavity behind the disk does not pass through the calibration hole. So the pressure rises, opens the bypass valve. A little fluid through the collector again enters the suction cavity. So the performance of the mechanism is reduced.
About the most characteristic breakdowns that are inherent in GUR
I must say that the malfunction of the Kamaz power steering does not happen often. With high-quality operation and timely maintenance of this unit, you can even forget about frequent adjustments. However, albeit infrequently, you can read about problems with the amplifier.
If it were not for the Russian winter, then the power steering would work all the time the truck was in operation. However, winter frosts, terrible roads often lead to too early deterioration of power steering mechanisms. Usually, all breakdowns can be divided into mechanical problems and hydraulic problems.
Both mechanical and hydraulic problems can occur anywhere in the assembly. Like any hydraulic system, the amplifier does not tolerate cold. Especially he does not like too drastic changes. The same pump pumps up quite a lot of pressure. Therefore, if the viscosity of the working oil suddenly rises, it can squeeze out the seals.
In addition, it is not always possible to observe at least the simplest rules for safe use. Often drivers leave cars with their wheels turned upside down in great frosts. After the engine is started, the pressure will increase only on one side. As a result, squeeze the gland. Also, few according to the regulations replace the hydraulic fluid. And it may thicken over time. This leads to excessive pressure.
But this is winter, but what about summer? And here the problems appear mainly due to dust or dirt. Only a very small depressurization of the system is enough, and soon the KamAZ power steering will be needed. So, during depressurization, the rods and bushings wear out. The former immediately rust and increase the wear of the latter. After a couple of hundred kilometers, the gaps between the rod and the sleeve will become more than acceptable. So, the steering rack will knock.
Keep clean and fluid level
That there were no problems with the power steering, you need to keep clean. Dirty hydraulic fluid can significantly accelerate the wear of the pump and seals in the mechanics of the steering rack of a truck.
You must try to look at the oil level in the tank. If the level is lower, the pump will operate in premature wear mode.
Symptoms of typical element malfunctions
If you need to constantly align the car with the steering wheel while driving, you must check the presence of free wheeling of the steering wheel. If it is higher than necessary, the stroke should be adjusted. You also need to make sure and check whether the parts of the screw pair are worn out.
If air enters the hydraulics in the tank, you can see foamed and turbid liquid. In this case, flush and bleed the system. The filter must also be replaced. In addition, one of the typical failures is a manifold gasket that can wear out.
Repair and adjustment
Repair work comes down to replacing worn parts or assemblies. All spare parts for the amplifier are manufactured and are in the diagrams of assembly units. Parts cannot be restored.
For adjustments, you must have a special tool - a dynamometer, and to check the pressure you will need a manometer.
So, we found out what the Kamaz power steering device has, faults, design and operation principle.