Course work on "Maintenance and repair of steering control MAZ-54328"

Contents

CONTENTS

Introduction

1. History of MAZ-

2. Steering

3. Steering Repair

4. Removal of steering gear from the vehicle

5. Steering rack test bench

6. Repair part

Conclusion

List of literature used

Introduction

Maintenance and repair (maintenance   , maintenance - maintenance and repair ) - a set of operations to maintain the operability or serviceability of production equipment (products, parts) during technical operation, storage and transportation.

Maintenance - preventive measures carried out systematically, forcibly through established periods, including a certain set of works.

All works to maintain the required level of equipment technical condition are divided into maintenance, repair, modernization and replacement. Maintenance is divided into regulated and ad hoc.

Regulated maintenance includes works performed in accordance with technical documentation in a mandatory manner after a certain mileage, operating time or time interval according to a previously approved schedule. Such works usually include: replacement of lubrication in units, replacement of some critical quick-wearing and easy-to-replace parts, testing of vessels and lifting mechanisms, adjustment and adjustment of critical working machines (for example, lifting machines), periodic maintenance according to special schedule and regulations, etc., as well as checking the technical condition of equipment using technical diagnostics and visually. Works on regulated maintenance are usually accompanied by stopping of working machines and are carried out according to a special schedule. Unregulated maintenance includes cleaning, tying, adjustment, addition of lubricant, replacement of quick-wearing and easy-to-replace parts, etc. The need for these works is revealed during periodic inspections, monitoring of technical condition using diagnostic systems and means of technical diagnostics. The detected comments are eliminated during process interruptions, transitions and usually without stopping the process, or with short-term shutdown. Ad hoc maintenance includes daily maintenance (ETO).

History MAZ-54328

In the mid-1930s, a large military unit of the Red Army was located on the territory of the future automobile plant. In 1942 , on the basis of the former repair pavilions of the 26th Panzer Division, the German invaders organized a plant for servicing and repairing Wehrmacht transport - cars and tanks. DaimlerBenz has built more than thirty repair pavilions. The GrosKverk plant with more than five thousand workers soon became one of their largest enterprises in occupied Eastern Europe. During the construction of the plant, forced labor of prisoners of war and local residents was widely used.

On August 9, 1944 , a resolution was issued by the USSR State Defense Committee on the organization of an automobile assembly plant in Minsk. Since the end of 1944, in parallel with the construction of the plant itself, the "screwdriver" assembly of GMC  and Studebaker trucks delivered from the United States under lendlise begins. After the Second World War, the assembly of American machines stops and the construction of the workshops of the future plant continues. Already in October 1947, the first five MAZ205 dump trucks were collected at the plant according to documentation and with direct technical support from the Yaroslavl Automobile Plant. In fact, these were YaAZ205, which had differences due to technological capabilities. From that moment, the plant was able to fully take over the manufacture of trucks of the YaAZ200 series "in accordance with the decisions of the party and government," which was completed, although not in one year. All production of biaxial YaAZ200, dump trucks, on-board trucks, truck tractors passed to Minsk. A little later, the three-axis series YaAZ210 of the same row was transferred to Kremenchug, where KrAZ began to work. Since then, for NPS, the main task has been to provide two plants with power units. The first MAZ205 cars, which left the factory gate at the end of 1947, became the beginning of the Belarusian automotive industry.

At the end of 1948 , the construction of the first, and in 1950 the second stage of the plant was completed. As a result, in the same 1948 it became possible to organize mass production of cars, and with the completion of construction, reach the design capacity and then surpass them. In 1951, the plant produced 25 thousand cars against 15 thousand planned ones. At the same time, not only car production increased - the result of the work of the designers was cars that the world automotive industry did not know. The world's first 40-ton dump truck MAZ530 at the World Industrial Exhibition in Brussels in October 1958 was awarded the highest award - "Granpri."

In November the 1958th on the Minsk automobile works samples of the MAZ500 and MAZ503 cars which should succeed cars of the first family - MAZ200 were collected. The transition to the production of machines of the new family required complex technical solutions, comprehensive tests of the equipment being created, and the reconstruction of production . On December 31, 1965 , the last car of the first MAZ family came down from the main conveyor - the MAZ205 auto dump, which took place on the pedestal of the monument with the first MAZs. The plant completely switched to the production of cars of the MAZ500 family, constantly increasing their production.

In  1966 , the company was awarded the Order of Lenin, and in 1971 - the Order of the October Revolution.

In September 1970 , production of modernized MAZ500A cars began, and in March 1976 , the first MAZ5549 dump truck from the new MAZ5335 family came off the main conveyor. In 1977, the plant was awarded its third award - the second Order of Lenin.

On May 19, 1981 , the first truck tractor MAZ5432 of the new promising family of cars and car trains MAZ6422 was assembled on the main conveyor of the plant. And less than two years later, on April 16, 1983, a thousandth car of this family was already assembled. The production of new cars continued to increase. April 14, 1989 was released million MAZ. It became the truck tractor MAZ64221. Preparations for the wide production of three-axle saddle tractors unfolded at the plant. In the late eighties , the MAZ2000 Perestroika concept car was created.

In  1996, after successfully passing acceptance and operational tests in the auto farms of the Republic of Belarus, a new model range MAZ5440 was recommended for mass production. On March 11, 1997 , the first main tractor of the new MAZ54421 family left the conveyor of the Minsk Automobile Plant. At the end of 1997, cars MAZ54402 and MAZ544021 were assembled, fully meeting all European requirements for heavy vehicles for international transport.

On December 10, 1997, an agreement was signed on the creation of a joint Belarusian German truck company MAZMAN. The difference between this project and other projects for the production of cars in the CIS countries was that the share of Belarusian units and parts will reach 60% in products produced at the joint venture.

On May 19, 1981 , the first MAZ5432 truck tractor was assembled on the main conveyor. The car was equipped with a YAMZ238F V8 engine of 14.86 liters with a capacity of 280 hp. The load capacity of the tractor was up to 21 tons, the total weight was up to 34 tons. From previous models, the car was distinguished by a new cabin with a large sleeping compartment, equipment and the presence of a transverse stabilizer in the front suspension.

In September 1983 , the Minsk Automobile Plant was awarded the Plovdiv Fair gold medal for the MAZ5432 road train with the MAZ9397 full trailer.

In  1985 , the MAZ5432 was replaced by the MAZ54322 truck tractor with a more comfortable cabin. In 1988 , the MAZ54321 model was added to it, which received new engines YaMZ8421 and YaMZ8424 with 360 and 425 hp. In the same year, cooperation began with the German company MAN (MAN), whose 360th strong engines were first installed on MAZ54326 tractors. Then they began to manufacture the MAZ54323 with a 300 hp YAMZ238B engine.

The total weight of a single car is 1625 tons, road trains - up to 44 tons. A novelty in this series was the MAZ543208 truck tractor with a new YaMZ7511 engine (400 hp).

Steering

The steering mechanism is a screw and a ball nut engaged with a toothed sector, with an integrated steering amplifier distributor. Gear ratio - 23.55. Power steering - with extended hydraulic cylinder.

Steering control of MAZ54328 vehicles includes a steering mechanism with an integrated distributor, a column, a steering wheel, a power cylinder, a pump, an oil tank, as well as hoses.

Steering mechanism of MAZ54328 vehicles with built-in distributor and operating fluid pressure limitation valve is shown in Figure 2. The axis of the outer surface of the inserts 8, 15 is displaced relative to the axis of the hole of the bearings 11 by the amount of eccentricity "h," which makes it possible to adjust the gear engagement by turning the inserts 8, 15. Adjustment of the tension of the bearings 29 is carried out using gaskets. The distributor of the rudder hydraulic booster - spool type, is built into the steering mechanism.

Steering care and adjustment of MAZ54328 vehicles. The maintenance of the steering gear consists in periodic inspection and tightening of the fasteners, as well as in checking the tightness of all seals. Adjustment of the tension of the pump drive belts on cars with a YMZ engine is carried out by a screw .

With the correct tension, the deflection in the middle of the belt under a force of 39 N (4 kgf) should be within 1015 mm. After adjustment lock the screw with nut.

When changing oil in the hydraulic system, which is carried out during repair, you should raise the front axle of the car. To drain oil from the system: - remove the filling plug and drain plug of the oil tank, drain the oil from the tank and wash the filter and tank with diesel fuel; - drain the oil from the steering case, for that turn the plug 30 (Figure 2); - disconnect the hydraulic cylinder pipelines from the distributor and lower them into the reservoir and slowly turn the steering wheel to the right and left until stop, drain oil from the hydraulic cylinder.

When filling oil, completely remove air from the system. To do this, pour oil into the tank and slowly turn the steering wheel twice until stop to the right and left, until the release of air bubbles from the oil in the tank stops. Add oil, if necessary. Replace the oil tank filter at installation of MAN engine after run-in, and then change after every 30000 km run.

Adjustment of the steering gear of the MAZ54328 cars includes adjustment of the screw bearings and adjustment of the engagement of the gear sector and the rack nut.

The adjustment of the mechanism should start with the screw bearings in the following sequence: - remove the steering mechanism: - drain the operating fluid from the steering mechanism by removing the drain plug: - attach the steering mechanism in the clutches and eyes of the housing in the horizontal position upwards by the sector; - turn the input shaft (Fig.2) to install the nut 3 and sector 7 in one of the extreme positions (left or right); - determine the moment required for turning the input shaft in the direction from the extreme position to the middle (approximately by an angle of 30 °). if the moment is less than 0.9 Nm, it is necessary to adjust the tension in bearings 29, reducing the number of gaskets 1.

After adjustment of the steering gear of the MAZ54328 vehicles, the torque required to turn the input shaft shall be within 0.9-1.5 Nm (0.100.15 kg/cm). 

To check the presence of the play in the gear engagement, it is necessary to rotate the input shaft to set the nut-rack and the toothed sector to the middle position (the total number of revolutions of the input shaft is divided in half), to install the bevel on the shaft of  sector 7.

By pumping the nozzle to both sides, determine the presence of a play (if there is a play, a knock in toothed engagement is heard and, in addition, the sector shaft rotates and the input shaft is stationary). The presence of the play can also be determined by turning the input shaft left and right before the torsion begins, thereby locking the sector shaft. To adjust the gear engagement in the steering mechanism MAZ54328, it is necessary to remove the covers 10 and 16 and turn the inserts 8, 15 clockwise by the same angle (viewed from the side of the sector shaft) so as to avoid a gap in the gear engagement.

Install covers 10 and 16 so that pins 9 enter holes in inserts 8, 15 located in the same diametrical plane with threaded holes in the housing for attachment of covers. At slight mismatch of holes with threaded holes of housing of inserts 8, 15 turn to one side or the other until coincidence of the above holes, at the same time paying attention to absence of clearance in toothed engagement. The pins 9 shall be aligned against each other. After adjusting the cover 10, 16 during installation, it is possible to rotate 90, 180 and 270 degrees relative to the original position.

After the covers are installed, the torque required to turn the input shaft in the middle position should be in the range of 2.9-4.5 Nm (0.29-0.45 kg/cm). After adjustment work, install the steering mechanism on the car and, connecting it to the steering column and hydraulic cylinder, check the steering operation.

With correct adjustment (with adjusted hinge joints of steering rods, front wheel hub bearings and pivot joints, the front axle beam is a swivel knuckle), the force on the steering wheel rim when turning the steered wheels in place, on an asphalt-coated site, should be at a running engine 98118N (1012 kGs) and a free steering angle of not more than 10 - 12 ° . During operation, it is allowed to increase the steering wheel free stroke, but not more than 18 °. Adjustment of the turning angles of sector 7 (Figure 22), at which the pressure limitation valve 13 operates, is carried out directly on the MAZ54328 car as follows:

In order to increase the rotation angles of the sector 7 and therefore the steerable wheels to the left to a predetermined value, it is necessary to turn the lock nut 24 before coming out of contact with the body 23, and to turn the plug 22 counterclockwise, whereby the nut 21 with the rod 20 and the lever 19 will move downward, ensuring that the roller 18 is removed from the side face 17 of the sector 7.

To reduce the rotation angles of the sector 7 and therefore the steerable wheels to a predetermined value to the left, remove lock nut 24 until it comes out of contact with housing 23 and, turn plug 22 clockwise, at that nut 21 with rod 20 and lever 19 move upwards, ensuring that roller 18 approaches side face 17 of sector 7. Turn lock nut 24 after adjustment, holding the plug 22.To increase or decrease the angle of rotation of the sector and, therefore, the steering wheels up to a predetermined value to the right by a similar adjustment, the roller 26 with the lever 25 is removed or approaches the face 27 of the sector 7.

Steering column of cars MAZ54328. Adjustment of steering column of MAZ54328 vehicles by inclination angle and height is performed at pressing of pedal (8) (Figure 3). At the initial moment of pressing the pedal, the rack 4 is disengaged and the position of the steering wheel is adjusted only by the angle of inclination.

Steering rack test bench

Steering racks provide easy and safe driving in the direction specified by the driver. Most often , steering rails are tested and tested when it comes to driver safety, since steering rails are worn out quite quickly.

Before testing the steering racks, which are subject to wear, are subjected to control measurements, the balancing of the rotating parts of the clutch is checked, the axial load to be applied to the pressure disk for complete disengagement of the clutch is determined, as well as the stroke of the pressure disk, after which the clutch is installed on the car. The clutch is rolled over a 200 km run of the car along a certain route with frequent turns occurring with a shift of gears. Frequency of turns is chosen so that normal running-in of parts takes place and overheating of clutch is avoided.

Depending on the category of vehicle and the steering rack device for which the clutch is intended, the practice of testing at the manufacturer and other circumstances, the program of road tests of the clutch and steering racks may include various modes reflecting the specifics of operation. However, all programs usually provide for a certain number of touches from the place in the lower gear, including at the maximum engine power mode, at the maximum level of operation of the steering racks, movement on lifts of various steepness, including lifts close to those that the car is able to overcome, as well as the movement of the car with maximum speed.

For tests of vehicle steering racks, open-type stands (stands with direct power flow) are used, in which loading of the box or bridge is carried out using a braking device, and closed-type stands (stands with closed power flow) with loading of the tested object by internal forces resulting from preliminary twisting of the shafts of the kinematic contour. On stands of the first type, relatively short-term tests associated with the removal of a particular characteristic are usually carried out, while stands of the second type as more economical are used for tests located for a long period, for example, for reliability, durability.

Tested box is installed between balance engine, steering racks and braking device, as which generator is used.

The operational reliability of the car is largely due to the ease of driving in the desired direction; It is provided mainly by technical condition of steering, suspension, angles of controlled wheels installation. The steering system shall automatically hold the direction of the vehicle in a straight line, ensuring that the steered wheels roll without sliding during rotation and automatically return to the straight-line position. It shall be possible to turn the steering wheel with minimal effort. Steering and suspension inspection tools are divided into tools for checking the installation angles of controlled wheels, checking the steering and shock absorbers. Means for checking the installation angles of controlled wheels.

The basis of all stands and devices for checking the installation angles of controlled wheels is a single method for checking the geometric position of the wheel plane in a rectangular coordinate system. The difference of most existing instrument designs lies in the measurement methods and measurement systems by which the position of the vehicle wheels is determined. Modern devices for checking the installation of wheels are divided into static and dynamic .

In static devices, mechanical measurement method, gravitational, electro-optical, optical and combined electric, is used to determine wheel installation angles. In the mechanical measurement method, there is mechanical contact between the bench sensors and the car wheel or special discs mounted on the wheels parallel to their plane. Devices of this type, having a direct reading on the scale of the value of the measured geometric parameter, include all kinds of rulers for checking the convergence of wheels. For example, K463, 2182, as well as various indicators such as clock type. Despite the design simplicity and low cost of these devices, it is not advisable to use them to control the installation angles of wheels of modern cars, since they do not provide sufficient accuracy. A group of gravity-based instruments includes all instruments and fixtures that use liquid levels.

Depending on the setting angle, the position of the air bubble in the ampoule changes; the position of the air bubble is recorded on a scale graded in angular units. In some devices of this type, such as the US 445, the position of the liquid meniscus in the glass ampoule is controlled by bridge electronics. The value of the installation angles can be read from electronic measuring instruments. The use of an electronic measuring system allows you to significantly increase the accuracy of measurements, reduce the verification time. A characteristic feature of electro-optical devices and stands designed to determine the angles of installation of wheels and displacements of car bridges is the presence of projectors, projection screens and a system of mirrors. With the help of various clamping devices, the light projector is fixed on the wheel, the axis of rotation of the projector should be perpendicular to the plane of the wheel .

Diagnostics of this type include K111 and PKO1, RKO-4. RKO1 stand (Fig. 8) includes: 1 - projector. 2 - rack.

3 - projection screens. 4 - quick disks. 5 - sliding rod. 6 - transformer, 7 - platform for rear wheels. Main elements of bench are installed on four rack hoist, projector on car disk by means of lower and upper consoles moving along two guide rods. Position of projector is adjusted with screws. The upgraded RKO4 stand (commissioning) has similar characteristics.

Domestic mass-produced stand K111 - stationary, electric. Wheel installation parameters are checked by projection method using electro-optical system consisting of two projectors and two screens with markings. The project is attached to the front wheel of the car. According to position of projector light spot on screen relative to control marks of scale, parameters of wheels installation are determined. The mutual position of the car axes is checked for parallel displacement - by the difference in the departure of the rear wheels to the left and to the right by projecting the projector beam onto the rulers installed on the rear wheels; on the skew - by the difference in the value of the base of the car, measured by roulette on each side of it .

Conclusion

It is especially necessary to determine the technical condition of the units when the unit or unit has failed. According to certain practically established signs, you can find an interface or node where operability is impaired. But this is an extreme case. It is desirable to anticipate the moment of failure in advance in order to exclude it.

In practical conditions, the unit (unit) is repaired, parts are replaced on the basis of existing experience in operating cars under given conditions, mileage to repair is estimated according to statistical data with a large error. Increased accuracy of evaluation of technical condition of the unit allows to reduce costs for repair of faulty unit due to prediction of vehicle mileage to the limit change of technical condition, if limit value, regularity of criterion change during operation and condition of unit (unit) for previous mileage are known.

The reason for changing the technical condition of the node is wear and tear. But, perhaps, only the technical condition of tires, gearbox, rear axle, steering is determined directly by wear - by changing the height of the tread, by gaps in gears, in hinges and other conjugations. The value of failure of units and units is estimated by the change of operating parameters: oil flow rate, gas break-through in the engine crankcase, noise, heating temperature, etc.

To maintain the rolling stock of road transport in the technically serviceable condition necessary for normal operation, a planned preventive maintenance and repair system has been adopted. The technical condition of the rolling stock is achieved by maintenance and repair.

List of literature used

Sinelnikov A.F., Vasiliev B.S. MAZ Cars: Maintenance and repair. – M.: "Politekh4", 2008.

Vlasov V.M., Zhankaziev S.V. Repair and devices of the car. - M.: "Third Rome," 2010.

Kuznetsov A.D. Theory and design of the MAZ car. Minsk, Academy, 2011.

S.F. Zelenin. Car devices - M.: "Knowledge," 2013.

V.F. Yakovlev. Truck arrangement. - M.: "Third Rome," 2011.

Shugurov L.M. Cars of the USSR. - Russia, Belarus, ILBI, 2011.

Rumyantsev S.I. Car repair. - Minsk, "Transport," 2007.

Volgin V.V. Your car - diagnostics, spare parts, service. - M.: Eksmo, 2010.

Epifanov L.I. Epifanova E.A. Maintenance and repair. - M.: "FORUM," 2012.

Vysotsky M.S. Gileles L.H. Car MAZ54322: Device, maintenance, repair. - M.: "Mtransport," 2007.