An improved design of an air spring with an air damper for self-regulation in terms of amplitude and frequency of oscillations of the Volzhanin and KAvZ bus system is presented. In the spring, an elongated piston is welded from two serial parts and made of PTFE-4 for operation without lubrication. Check valves are closed with thin elastic tubes, as an elastic rod - a wire with a diameter of 3 mm from spring steel. The operating modes and dynamic elastic characteristics of the air spring are shown. The optimal design parameters were tested on the stand. Suspension hydraulic shock absorbers can be abandoned, which simplifies the design, reduces costs and increases reliability.
1.1 Information about the bus MAZ-103
Rice. 1. Bus MAZ-103
Brand:……………………………………………………………………MAZ-103
Manufacturer:……………………… RUE "Minsk Automobile Plant"
Body type:…………………………………………………………………bus
Number of doors:……………………………………………………………………...3
Overall dimensions, mm………………………………………..11985-2500-2838
Outer turning radius, mm……………………………………………11300
Number of seats…………………………………………………...24
Maximum speed, km/h………………………………………………..…80
Engine……………………………………………….Deutz BF6M1013EC (E2)
Displacement, l:………………………………………………………………..7.12
Engine power, kW (hp)………………………………………... 174 (237)
Gearbox………………………... Voith Diwa D851.3E (automatic)
Wheels………………………………………………........... disk, 8.25х22.5
2 General form and arrangement of suspension units for the bus MAZ-103
When analyzing the suspension of the MAZ-103 bus, we select the main elements and present a detailed arrangement of the units in order to identify the main failures and malfunctions during the operation of the MAZ-103 bus.
2.1 Front suspension
Rice. 2. MAZ-103 front suspension device
1-cylinder air suspension assembled; 2.3-Nut M30x1.5-6H; 4-Washer 12OT; 8-Bolt М12х1 25-6Н; 9-Nut М8-6Н; 10-Washer 8T; 12-Bolt М8-6gx50; 13-Splint 1.6x20; 14.18-Clutch; 15-Washer 6; 16-worm clamp; 17-Axis; 19-Thrust; 20-Shock absorber; 21-Hub with a fist and brakes, right; 22-The base of the front suspension; 23-Amplifier; 24-Nut; 25-Nut М10-6Н; 26-Screw М10-6Н; 27-Splint 5x36; 28-Nut М24х2-6Н; 32-Traction transverse; 33- Left hub with fist and brakes; 34-Sleeve; 35-Traction transverse; 37-Bolt M18x1.5-6N; 38-Bolt 3M14x1.5-6gx50; 39-flange; 41-Sleeve; 42-Key 6x9; 43-Finger; 44-stand; 45-Piston; 46-Buffer; 47-Sleeve; 48-Washer 14; 49-Washer 14L; 50-Bolt M14x1.5-6gx50; 51-Rubber cord sheath; 52-flange; 53-Bolt M18x1.5-6N; 54-Nut M18x1.5-5H6N.
2.2 Front suspension
Rice. 3. Front suspension device MAZ-103
1-Axis front; 2,3-support; 4.5-reactive rod; 6-shock absorber; 7-Cylinder air suspension assembly; 8-Body position regulator; 9-Regulator rod; 10-Axis; 11-Sleeve; 12-flange; 13-Ryachag; 14-Bolt 3M14x1.5x6gx50; 15-splint; 16-Nut М8-6Н; 17-Bolt M8x6gx50; 18-Bolt M8x6gx25; 19-Washer 8T; 20,28-Buffer; 21-Washer; 22-Bolt 3M24x2-6g-60; 23-Splint 1.6x400; 24-Splint 5x36; 25-Nut M30x1.5-6N; 26-Flanets; 27-Piston; 29-Sleeve; 30-Bolt m14x1.5-6; 31-Washer 14; 32-Washer 14; 33-Rubber cord sheath; 35-Tip right; 37-Bolt; 38-Washer; 39-Nut.
2.3 Suspension bar
Rice. 4. The device suspension rod MAZ-103
1-Head; 2-Bolt M12x1.25-6gx60; 3-rod; 4,5-Hinge; 6,7,16,18,19-Ring; 8-rod head; 9-Hinge; 10-Washer 16OT; 11-Bolt M16x1.5-6gx60; 12-Ring 140; 13-Nut M12x1.25-6gx60; 14-Washer 12OT; 15-Pipe; 17-Hinge.
2.4 Rear suspension
Rice. 5. Rear suspension device MAZ-103
1-Traction transverse; 2-Beam; 3-Axis lock cylinder; 4-Hub; 5-Brake right; 6-Brake left; 7-lid; 8-Gasket; 9-Washer; 10-Nut; 11-Bolt M12x1-6gx90; 12.13-Knuckle swivel; 14-Lever tropezia left; 15-Lever tropezia right; 16-Shock absorber; 17.18-reactive rod; 19-Pneumatic balloon; 20-flange; 21-Plate; 22,29,30-Nut M32x2-6N; 23-Bolt M24x2-6gx90; 24,25,26,27-Bolt; 28.31-Washer 4; 32,33,34-Washer 16OT; 35-Splint 5x45; 36-Splint 6.3x71.
new bus starts back in 1992. Then the MAZ plant, known in the world as a manufacturer of a wide range of trucks, had no experience in the development of passenger transport. The agreement with the well-known German manufacturer Neoplan on cooperation in production allowed the Minsk plant to obtain a license for production and the necessary technologies, which significantly reduced the time and cost of development at the initial stage.
This step for the young republic was not from the field of image, and not even in the field of economics - its own bus became a vital necessity, since the Hungarian Ikarus, widespread in those years in the USSR, with the collapse of the CMEA, began to curtail production and supplies to the CIS countries, including, and in connection with the difficult economic situation in the republics of the former USSR, including with the currency. Depreciation rapidly brought the Ikarus bus fleet out of service. Replacement was required, and cost-effective and operational.
As a result, the largest machine-building plant successfully mastered independent production, and already in 1993 the first six Belarusian buses, which were a copy of the basic model, rolled off the assembly line. However, the final cost of the assembled buses turned out to be significantly high - about 200 thousand dollars, which made the project unviable, especially since the former CMEA republics sought to "cheap" their old "Ikaruses". Plus, the life of the equipment in conditions of non-ideal roads turned out to be low. And as a result, adaptation to local conditions and local components began.
The result of the work was launched in 1996 in mass production low-floor bus MAZ 103. Due to the reduction of imported components to a minimum (up to 10%), the price turned out to be more than two times lower than competitors, the cost of ownership also decreased, maintainability and service life increased in the operating conditions of Belarus and the CIS countries.
It should also be noted that the Maz 103 was the first low-floor bus produced in the CIS countries. It turned out to be roomy, safe and comfortable - meeting world standards, thanks to which it has gained popularity outside the Republic of Belarus.
Technical features
Scheme bus chassis made according to the classical scheme, with a rear driving axle, with a bevel gear.
MAZ-103 is already presented today in several modifications - for suburban passenger traffic, with a different number of doors (without back door), with a different number of seats, and with different capacities.
Bus seat arrangement MAZ 103 is made according to a three-row scheme - double on the left and single on the right. Opposite the middle door is a storage area.
Driver's cabin with an ergonomic arrangement of controls, with a comfortable seat and adjustable steering column. The dashboard has no frills, but is made at a modern level and is fully consistent with the task of reliable and comfortable control.
Historically, the bus began to be equipped with engines of the Minsk Motor Plant, with a capacity of 230 hp. They were unnecessarily large, heavy, lacking power, and the noise was just above what was desired. For these reasons, in the early 2000s, MAZ 103 buses were equipped with Renault engines- more reliable and powerful (250 hp), there were also modifications of DEUTZ, Mercedes.
Power plants of the line
Currently, only Mercedes-Benz engines (286 hp or 326 hp) are installed. Units of a well-known manufacturer from Germany are distinguished by a high degree of reliability and efficiency and comply with more stringent environmental standards (Euro-5).
In terms of gearboxes, the bus was initially equipped with a 6-speed self-produced one, but it was not compatible with a number of engines, which forced the designers to look for other options, as a result, most buses were equipped with a 5-speed Praga gearbox. Recently, configurations have been offered with a manual transmission manufactured by ZF or an automatic from Voith or Allison.
Long-term operating experience of the model has shown its reliability and efficiency. Low comparative cost of operation and cost of spare parts. In addition, spare parts can be ordered through an advanced system official dealers factory.
The price of MAZ 103 at the end of 2015 is from 6,500 thousand rubles for a new bus.
Basic elements of a complete set of a series
- 30kW Webasto independent liquid engine heater used for preheating engine and interior heating
- Driver cab independent air heater 2.0-2.2 kW (Webasto or Eberspacher)
- Anti-lock braking system ABS
- Traction control ASR
- Radio equipment without radio: microphone, amplifier and 4 loudspeakers
- Thermal soundproof ceiling
- Anti-corrosion treatment of the bottom and hidden cavities
- Folding ladder for wheelchair access
- Equipment and attachment for one wheelchair
- Forced body tilt system "Kneeling"
- The driver's seat on an air cushion, adjustable, manufactured by OJSC "MAZ"
- Wear-resistant coating "Grabiol"
- Galvanized sheet on the sides and roof
- Stop request buttons
- Screw-in towing forks
- Partition separating from the salon workplace driver and dividing the doorway into two parts, without access to the passenger compartment
Advantages and disadvantages
The advantages of the model include, in addition to the above, high visibility in the driver's cab and high maneuverability.
Thanks to the low floor, disembarkation and embarkation of passengers is carried out quickly and conveniently, stopping time is reduced.
The disadvantage of the bus can be attributed to the large dimensions of the engine located in the rear of the cabin, because of which it was not possible to implement a stepless entrance, equally low for all three doors. As a result, the floor height for the rear door was 580 mm, against 360 mm for the front and middle. Also, a 220 mm high step was formed for the rear door.
Passenger transportation both on city routes and between settlements- a demanded and very profitable type of service. However, the requirements for passenger transport oblige company owners to periodically update the rolling stock of their enterprises. This is due to the fact that every day there are new criteria that are directly related to the safety and comfort of passengers. The purchase of expensive foreign-made buses is far from affordable for every enterprise, and the operation of old vehicles inevitably leads to the deprivation of a license. The way out of this situation is to search for cars from domestic manufacturers.
Modern and safe bus. MAZ - an alternative to overseas manufacturers
Surely everyone remembers the time when old LiAZs, LAZs and Ikarus cruised along the roads of cities and suburbs, carrying out passenger transportation in various directions. However, they are not only morally obsolete, but also completely do not meet modern safety and comfort requirements, which means that the fleet needs to be updated. MAZ buses are an alternative way out of the situation.
Thanks to modern developments, designers have created a number of MAZ buses, which are in great demand today due to their modern design, comfort level and compliance with all passenger safety requirements. After the collapse of the Land of Soviets, the once eminent automobile manufacturer was going through very difficult times. Along with this, there was a need for a complete renewal of the fleet that provided passenger transportation services. And in 1996, the first MAZ bus rolled off the assembly line, which became a replacement for the morally and technically obsolete Ikarus for a long time.
The first model, although it met all the requirements, was far from ideal and was constantly improved over time. Along with it, new options were developed, which, due to their quality, gained confidence and became widespread both at home and in the post-Soviet expanses.
Brief technical characteristics of power units installed on MAZ buses
Bus MAZ-103 for urban passenger traffic
It is made up of:
- Length 11.985 m.
- Width 2.5 m.
- Height 2.838 m.
The salon is equipped with three doors 1.2 m wide, and with the number of seats, which ranges from 21 to 28, it can accommodate 70 - 110 passengers. The cabin height is 2.37 m, which makes the trip comfortable even for people whose height is more than 190 cm, and the width of the passage between the seats is 73 cm. The heating is liquid and completely independent of the bus power unit. It is implemented by means of a 30 kW engine heating system. It also makes it easier to start the engine when operating the vehicle in low ambient temperatures. The driver's cab is heated by a separate air heating system, the power of which is 2-2.2 kW.
The line of power units that are installed on buses consists of three engines. These are Mercedes-Benz OM 906LA and DEUTZ BF6M.1013EC - foreign-made four-cylinder in-line diesel power units that are paired with automatic ZF and Voith Diwa. As well as domestic diesel, which is installed in tandem with mechanical five-speed gearbox gears Praga 5PS 114.57.
Great transport for city and suburban flights
Unlike previous version with a width of 2.5 m and a height of 2.838 m, the MAZ bus
107 is equipped with a large number of seats, which can vary from 24 to 30, and the total cabin capacity now reaches 150 passengers. This is due to the fact that the length of the body has increased and instead of 11.985 is 14.480 m. This model The bus is equipped exclusively with an in-line four-cylinder diesel power unit Mercedes-Benz OM 906LA. Its working volume is 6.3 liters. Installed in pairs automatic transmission gear that allows you to develop top speed up to 78 km/h.
High capacity for urban routes
The MAZ-105 bus is an excellent model of passenger transport with an especially large capacity for urban transportation. This bus, thanks to design features and the articulation of two salons together, reaches almost 18 meters in length and is equipped with 4 doors. Their size is considered standard for vehicles intended for city trips and is 1.2 m. Like the two models described above, the MAZ-105 bus is low-floor, as evidenced by the height of the first step in relation to the ground, which is 34.5 centimeters. This indicator is another proof that all developments were aimed at the comfort of passengers, and landing in vehicle will not complicate even people of advanced age or short stature. With such impressive dimensions, only 36 seats are installed in the passenger compartment of the bus. And the estimated passenger capacity should not exceed 160 people.
The power unit installed on this model is Mercedes-Benz OM 906LA. It is paired with an automatic transmission. The maximum allowed speed is 70 km/h.
Passenger baby from Belarus - the best option for commuter flights
The MAZ-256 bus is an excellent solution for entrepreneurs and fleets that provide services for intercity transportation of passengers over medium distances. With its small dimensions, the bus interior accommodated 28 seats, and the size luggage compartment reaches a volume of 2 cubic meters. The body of passenger transport, as well as in the bus, is made of plastic. All panels are glued into the frame. Also, the manufacturer provides several options for machines: tourist bus, fixed-route taxi and transport for long-distance passenger traffic.
The MAZ-256 bus is equipped with an MMZ-D 245.30 power unit and a SAAZ-695D five-speed manual gearbox. This tandem allows you to reach speeds of 110 km / h.
The comfortable city bus MAZ 103 is used for passenger transportation. Its production began in 1996, but 1992 is considered the official year of birth, it was then that MAZ signed an agreement with the German company Neoplan, which specializes in the production of buses. The need to create a local bus production in Belarus was due to the fact that the number of vehicles regularly supplied from Hungary began to noticeably decrease, and the depreciation of the existing vehicle fleet was already making itself felt.
Unfortunately, there was not a single enterprise in the country that would produce passenger buses, so MAZ, the largest machine-building plant in Belarus, had only one way out - to master production on its own. For this, within the framework of the signed agreement, Neoplan transferred a license to the Minsk plant to manufacture the bus.
A year later, in 1993, six new buses were produced, which practically did not differ from the base model. However, this was not good enough. First, the cost of the assembled buses was shockingly high - $200,000. In the mid-nineties, not a single enterprise could afford to spend such money on the purchase of transport. In addition, used Icaruses from neighboring Germany cost several times cheaper. Secondly, the bus had many shortcomings, and its service life on Belarusian roads would have been very short.
The question "what to do?" did not stand in front of the plant for a long time. The decision to adapt the bus to local operating conditions was obvious. No sooner said than done. The designers immediately began to refine the design of the transport and began to look for options to replace imported elements with more affordable locally produced parts. At the time of work, the bus was assigned the MAZ-101 index. In 1996, the Belarusian plant introduced the first low-floor bus in the country - MAZ 103, which was immediately launched into mass production. The price of the updated transport has become almost 2.5 times lower. It was possible to reduce the cost of production due to the fact that the share of imported MAZ 103 spare parts was reduced to 10 - 15%.
Comfortable and spacious passenger bus
There is no need to talk about the merits of the low sex. Disembarkation and embarkation of passengers is carried out more quickly and conveniently, and this, in turn, significantly reduces the time of travel along the route. I must say that the MAZ designer failed to fully reproduce the design of the German Neoplan. Due to the fact that the engine had impressive dimensions and was located in the rear of the cabin, the floor there was raised. The stepless entrance remained at the front and middle doors, where the floor level reaches 360 mm. In the area of the rear door, the floor height was increased to 580 mm, which required two steps.
In general, the MAZ 103 bus turned out to be comfortable, roomy and safe and quickly gained popularity not only at home, but also abroad. In addition, the transport was distinguished by good indicators of maneuverability, which allowed him to feel more confident in conditions of dense urban traffic.
The rear axle, which is the leading one, is offset from transverse axis bevel gear and is made according to the classical scheme. MAZ-103 is presented in several versions: in addition to the main model, the manufacturer also offers a modification for suburban passenger transportation - MAZ-103C. Differences - in the number of seats increased to 45 and the absence of a back door. base model It has several configurations, differing in passenger capacity and number of seats. The number of passengers carried is 90 - 100 people, and the number of seats is 21 - 28.
Concerning internal device bus MAZ 103, the arrangement of passenger seats is made according to a three-row scheme: on the left side - double, on the right - single. Opposite the middle door is a spacious storage area. The driver's cab is quite spacious, with a convenient location of controls. Although the instrument panel is a bit angular compared to Western bus models, the information on it is easy to read.
From the cheapest to the most expensive: engine options may vary
Specifications MAZ 103, along with modern design and a high degree of comfort were another reason to be proud of the new bus. The very first models of passenger transport were equipped with YaMZ and MMZ engines, but already during operation it became clear that the Yaroslavl engines were absolutely not suitable for it. They were not powerful enough, but noisy, large, heavy and poorly compatible with the gearbox proposed by the designers.
The engines of the Minsk Motor Plant, with a power of 320 hp, at that time turned out to be the best option and for the first few years of production, all low-floor trucks were equipped with them. Until 2004, Renault engines were also installed on MAZ 103 buses. More reliable and powerful (250 hp), they aroused more confidence among drivers.
MAZ currently offers several engine options, including Mercedes-Benz (231 hp) and Deutz (237 hp). Units of well-known foreign manufacturers are distinguished by a high degree of reliability and comply with more stringent environmental standards.
If we talk about the gearbox, then initially the bus was equipped with a 6-speed transmission of its own production, but its incompatibility with a number of engines forced the designers to look for other options and most buses began to be equipped with a 5-speed Praga gearbox. Recently, MAZ offers buses with a manual gearbox manufactured by ZF or hydromechanical company Voith.
Long-term operating experience of this model has shown that the transport is quite reliable, copes with significant loads, and the possibility of breakdowns is minimized. If repairs are needed, all spare parts for MAZ 103 buses can be purchased through official dealers of the plant, since their network is widely developed in our country.
The price of MAZ 103 starts from 4,105 thousand rubles for a new bus.
Photo of the passenger bus MAZ 103
The production of buses in Minsk was conceived back in 1992-1993. Then German company Neoplan bought a license to produce a low-floor city bus of the 4014 series. However, the released model “did not go” due to great price and expensive service. To save the situation, it was decided to make cars using Belarusian and Russian components, while maintaining the “neoplan” design and layout. So in 1995, our hero appeared on the conveyor, produced by AMAZ, the bus branch of the Minsk Automobile Plant.
In addition to Belarus and Ukraine, the MAZ-103 is also supplied to Russian cities: St. Petersburg, Yaroslavl (an assembly plant for Maz buses has also recently been organized there), Novy Urengoy, and so on. This year it was the turn of Moscow, which received 80 new cars. Using their example, we will analyze the design features and the first operating experience. Since the bus is low-floor, there are no steps. The height of the footrest above the road is only 335 millimeters, so in spacious salon just going in, not climbing like a climber. Inside, at first it’s unusual: you go low, and because of the huge glass area you feel like a fish in an aquarium put on public display.
But the passengers seem to like the car. Drivers said that at first, many people at stops did not even deliberately get into passing buses, waiting for the MAZ-103 to roll up to the stop - you have to try out the novelty! Not deprived of attention and the driver. The air suspension seat has three degrees of adjustment, and steering column adjustable in height and angle. Near the seat is an independent Webasto air heater. On the dashboard indicators of sensors that monitor the condition of filters and the main components of the bus are displayed.
In addition, if, for example, the system detects a low coolant level or lack of oil in the power steering, Emergency Signal on the panel is duplicated by a buzzer. The electrical wiring runs along the ceiling and is led to a single switching unit, standing on the outer wall of the driver's cab. The design features include a constant “mass”. Only the “plus” is turned off, but at the same time, the necessary control units over the machine remain under current. Now about problems. The first is assembly flaws. The panels in the cabin rattle and creak, so the drivers have to do the “noise isolation” on their own, laying the details with foam rubber. The second problem is electrical. The system itself is quite complex and difficult to understand.
Different relays fail (also, by the way, Mazovsky): direction indicators, wipers, and so on. Due to the ingress of moisture, failures of the pneumoelectric sensors for turning on the brake lights and the air pressure indicator also occur. There were also problems with heating the passenger compartment: some buses had a batch of low-quality rubber pipes through which antifreeze flowed. Installing additional clamps eliminated the leak only for a while. The problem disappeared after installing better products from another factory supplier. The manufacturer took this trouble into account and now, for insurance, additionally puts pipes on sealant. At the request of the customer, MMZ, MAN, Mercedes-Benz or Renault engines are installed on the MAZ-103.
All buses operating in Moscow are equipped with one type of engine - a Renault in-line diesel engine of the MIDR 06.02.26Y41 series. 6 cylinder engine with turbocharging and intercooler with a working volume of 6.18 liters. develops a power of 250 hp. and produces 950 Nm of torque, which is quite enough for a 12-meter colossus gross weight 18 tons. Part of the engines meet Euro-1 environmental standards, part after equipping a mechanical high-pressure fuel pump electronic control fit into the Euro-2 standard. We throw back the hood and immediately pay attention to the unusual layout of the nodes. Due to the low floor of the cabin, the engine did not fit in the center of the compartment, so the engine and its units were moved to the left side.
As a result, there is an engine shaft in the cabin, which passengers at first mistook for ... a toilet, fortunately, that the dimensions are suitable. On the other hand, although this box eats up part of the rear platform, you can get to the engine through a large hatch without leaving the cabin. The motor radiator is placed almost under the roof, which creates the effect of a water tower: antifreeze will enter the system under any conditions. Expansion tank, in addition to the main section, it also has a backup section, where, in case of excessive expansion, excess coolant and steam go, thereby protecting the system from rupture in case of overheating. The engine itself has a rather high thermal regime - 80-90 o
Interestingly, the radiator fan has hydraulic drive, for which a second oil pump is put on the engine. For the Germans, this system works without failures, but at MAZ, due to low-quality seals, pressure filters and control valve blocks that set the fan speed began to leak. (By the way, they say that similar valve blocks were previously used on hydraulic transmissions of mechanisms for deploying and controlling missile systems. And during the time of the Union, designers would have already worked on eliminating the above malfunction in Kolyma ...).
Everything would be fine, but the oil gets to the second generator located at the very bottom of the engine compartment (the standard unit is not enough to meet the needs of the electrical system, so the plant additionally installs another of the same generator). The residents of Minsk took this into account and began to put one powerful generator on top of the engine on the cars coming off the assembly line. Along the way, the designers simplified the fan hydraulic drive system, redesigning it according to German version, thereby eliminating the problem of leaks: instead of the valve control unit, an oil pressure regulator with control from a temperature sensor was installed, and a pressure filter was installed in a sealed tank.
In order to reduce the cost of construction and simplify maintenance, the engine is equipped with a Mazov exhaust system. So the sound of the motor is appropriate and clearly not “French”. Speaking about the engine, it is also impossible not to mention that the car is equipped with automatic fire extinguishers: three of them are in engine compartment, one - above the liquid heater of the engine. Very useful things, given that the engine is actually in the cabin. In general, in addition to the above-mentioned malfunctions of mounted units, there are no comments on the engine itself yet. The motor is reliable, starts well in winter and is quite suitable for operation in Russia.
However, the repairmen would prefer to see a Mercedes-Benz engine on the car, which is already well studied on the 0325 series buses of the same name, which are produced in Turkey. And although the plant trains fleet mechanics to work with equipment, the French engine is still new for Moscow and there is still little experience in operating and repairing this engine in the capital. MAZs operating in Moscow are equipped with two types manual gearboxes. (The design also provides for an automatic transmission "Voith"). Sixty-six out of 80 cars have a 5-speed Czech gearbox Rgada 5RP4 (MAZ-103-041), the rest have a 6-speed Renault G406 gearbox (MAZ-103-040) with a Valeo clutch. There are no comments on the French unit yet. At several Czech checkpoints, there is already a problem: the fourth gear spontaneously turns off on the go.
You have to either ride in third or jump from third to fifth. Naturally, such a “torn” driving style does not add life to the clutch. It is noteworthy that there are practically no such problems on buses operating in Minsk. It is still difficult to say whether a batch of checkpoints came to Moscow with a defect or there are some other reasons. Now engineers are working on this shortcoming and, hopefully, in the future they will get rid of it. The suspension of the bus is pneumatic, on six cylinders. Note that the front suspension is independent, on two wishbones. This design made with the expectation of installing (by order) a system that, after “mooring” to a stop, bleeds pressure in the air bellows on the right or left side, filling the bus on its side so that it almost lies on the ground, making access to the passenger compartment even easier.
The suspension has an active mode of operation. With the help of three air valves, several positions of the height of the body above the road can be set. And when driving, the system not only maintains a predetermined level, but also prevents the car from falling in corners, increasing or decreasing the pressure in the pillows. There is also a weak link here. Pneumocranes are connected to the suspension arms and, perceiving their moves, properly bypass air from one cylinder to another. These cranes are located in a not very protected place: two front ones are in the wheel arches, one rear one is near the bridge. The dirt flying from the wheels penetrates the faucet and its plastic piston begins to seize.
The pressure is not released properly, and as a result, the bus travels skewed to one side. True, this defect was not endemic and mainly occurred on several buses of early production, where the cranes may not have been finalized yet. After replacing faulty nodes with better ones, the problems tended to stop. Brakes on all wheels - drum, with self-adjusting gaps and ABS. But today you will not surprise anyone with this. But the fact that the entire pneumatic system is laid along the ceiling is something you don’t see every day and not on every bus! Although air system has an air dryer, valves for draining condensate are placed under the driver's window. There are similar drain taps on other buses, but on MAZ they are the easiest to use: I threw back the panel, removed the caps, pressed on the washer - and water started flowing.
By order, another interesting function is put on the bus, aimed at improving safety: when the driver presses the button to open the doors, the automation simultaneously “fixes” the bus with a parking brake. Steering with distributor and separately standing hydraulic booster also taken from cargo MAZs. Of the malfunctions, on about a dozen cars, extrusion of cuffs on the booster pump and steering gear was noted. Mechanics attribute this to the fact that these machines stood idle for several months before commissioning for various reasons. At the same time, the lubricant embedded in the units has outlived its shelf life and, having thickened, began to squeeze out the seals during operation.
©. Photos taken from publicly available sources.