Gearbox of the YuMZ-6 tractor. Device and circuit

The history of the creation of the YuMZ-6 tractor

The first samples of this model were assembled at the Southern Machine-Building Plant in the city of Dnepropetrovsk in 1966. The prototype for the described tractor was the MTZ-5, which was developed by the design bureau of the Minsk Tractor Plant. This model was produced at YuMZ starting in 1958. During the modernization, many technical solutions were retained, providing the machine with high performance characteristics.

YuMZ-6 tractors were mass-produced starting in 1970, the last copy left the plant’s assembly line in 2001. During the production process, various changes were made to the design; a total of four modifications were developed. We are talking about the following models: YuMZ-6L, YuMZ-6AL, YuMZ-6K and YuMZ-6AK.

The design of the tractor was so successful that it attracted interest abroad. In particular, in 1974, technological documentation was purchased from the Soviet Union by the Swedish company Volvo. Based on the YuMZ-6, the Volvo BM-700 model was developed, which was produced from 1976 to 1982. This technique has proven itself well in the difficult climatic conditions of Scandinavia.

The YuMZ-6L tractor was produced from 1970-1978.

The last tractor of this series, modification YuMZ-6AKM-40.2, left the factory assembly line in 2001 and was discontinued as morally and technically obsolete. This model was replaced by YuMZ-8040.2, YuMZ-8040.2M, YuMZ-8244.2 and YuMZ-8244.2M. The described tractor has been produced for more than 30 years, which indicates significant potential.

General description and technical characteristics of the YuMZ-6 tractor

The layout of this model is classic for vehicles of this class with a 4x2 wheel arrangement. The skeleton of the YuMZ-6 tractor is a semi-frame, made up of two longitudinal spars and a transverse front beam. The clutch and gearbox housings are attached to this structure.

In the front part of the tractor, a front axle with steered wheels is hingedly mounted on the frame, the rotation of which is ensured by axles. At the rear, the car rests on axle sleeves rigidly attached to the gearbox housing. This design is the simplest and most reliable. The drive is permanent to the rear wheels through the axle shafts of the final drives.

The tractor is equipped with low-pressure pneumatic tires with developed lugs to ensure high maneuverability. The wheels have different diameters, the tire size in front is 7.50-20 or 9.00-20; rear – 15.5R38. This technical solution is typical for machines in this category and provides them with fairly high technical characteristics.

Tractors of the YuMZ-6 series belong to the 1.4 traction class, which makes it in demand in various fields of management. The machine is equipped with:

• separate-unit hydraulic system;
• electrical equipment with a 12 V on-board network;
• pneumatic system;
• rear linkage mechanism for equipment.

The steering of the tractor is equipped with a hydraulic booster; the rotation of the front wheels is ensured by a trapezoid through a longitudinal link. The latter is connected to the shaft of the three-spoke steering wheel through a cardan transmission. The service brake system is pneumatic, shoe or disc type with pedal control. The parking mechanism is activated by a lever secured by a ratchet.

The YuMZ-6AL tractor was produced from 1978 to 1986.

2.1 Dimensional and weight parameters

Tractors of the YuMZ-6 series belong to the category of medium-sized, universal machines.

The main mass and dimensional characteristics of the machine are as follows:

The overall and weight characteristics of the YuMZ-6 tractor may differ from those indicated above, depending on the modification. The dimensions of the vehicle and rational weight distribution provide it with excellent maneuverability and maneuverability. Use in limited areas, in industrial and agricultural buildings, in forests and open spaces is allowed.

2.2. Tractor engine YuMZ-6

Tractors of the YuMZ-6 series are equipped with diesel power units of two models D65M and D65N, which have different structural weights of 525 and 540 kg, respectively. The engine is installed in the front part in front of the cabin and secured with rubber-metal supports on the frame. The power unit is covered from above and from the front by a hood; removable steel panels are installed on the sides. Main technical characteristics of the engine:

The diesel engine is naturally aspirated without turbocharging, which greatly simplifies its design and operation. The power unit has a liquid cooling system with a front-mounted radiator. Fuel is supplied from a tank located behind the cabin and shielded from external influences by a steel sheet. The manufacturer guarantees a minimum engine life of 10 thousand hours before the first major overhaul.

2.3. Gearbox of the YuMZ-6 tractor

Tractors of the YuMZ-6 series are equipped with mechanical gearboxes, the latter are designed to change gear ratios, provide reverse movement and power take-off. The design allows the engine to operate with the tractor stationary and the clutch engaged.

The gearbox of constant gearing and three movable carriages has five stages with manual lever control. The unit is equipped with a reduction gearbox, which allows the number of modes to be doubled. The primary shaft, mounted on roller bearings, rotates the secondary or PTO shaft through a system of gears and clutches.

The design of the box eliminates the possibility of engaging two gears simultaneously through a special rocker. There is also a locking mechanism to prevent the engine from starting if the gearbox is not in neutral. The parts and components of the gearbox are lubricated with oil located in the crankcase by partially immersing the gears and spraying it.

2.4. Chassis and transmission of the YuMZ-6 tractor

The YuMZ-6 universal wheeled tractor is equipped with reliable mechanisms for transmitting and converting torque from the engine to the wheels. The chassis includes:

• Main clutch. Double, permanently closed with a dry sump, operating principle is frictional. In addition to the main clutch, there is a separate clutch mechanism for the PTO drive; the control of the main and additional devices is separate.
• Gearbox (described in detail above).
• The rear axle is in the crankcase, on which the main and final drives are installed, between which there is a differential.

The front wheels are mounted on fixed axles, which in turn are mounted on rotary axles. The bridge beam is telescopic, which ensures a wide range of track changes. The rear wheels are mounted on axle shafts supported by ball bearings installed in the final drive sleeves. The axle housing is filled with transmission oil, which provides lubrication of the mechanisms.

3. Cabin of the YuMZ-6 tractor

Cabin of the tractor YuMZ-6 AKL 1992.

The described model is quite easy to operate and has a comfortable workplace for the operator. The cabin of the YuMZ-6 series tractor is distinguished by its structural strength and is equipped with a spatial frame for driver safety. Entrance is through doors located on the sides.

The glazing is two-level with large panoramic windows along the perimeter in the upper part, as well as small ones at the bottom of the front panel and both doors. There are rear-view mirrors and windshield wipers with electric drive. The rear and side windows open by turning around a horizontal axis installed in the upper part.

The cabin of the YuMZ-6 tractor is mounted on four rubber shock absorbers supported by a frame in the front and wing brackets in the rear. The following elements are located here:

1. The driver's seat is height-adjustable and mounted on a spring shock absorber.
2. Controls: Steering column with a mechanism for steplessly changing the position of height and reach.
3. Gear shift levers, gearbox parking brake and power take-off shaft mechanism.
4. Pedals: clutch and brake system.

The cabin is equipped with large rear-view mirrors and visors to protect from direct sunlight. Temperature and humidity conditions are provided by a built-in heater with a fan. There is a drawer for placing a first aid kit, an ashtray, and the basic package includes a thermos for water and a special clip for its placement. The cabin is considered excellent by experts in terms of ergonomics and convenience.

Transmission

The transmission type of this model is mechanical, with nine speeds.
To control the unit drive gearbox and the gearbox (five-speed, with movable gears), one lever is used. The steering column can be adjusted both in height (infinitely variable) and by rotating it (there are four fixed positions). The steering wheel is controlled using a hydraulic booster. The friction clutch is a double-flow type, permanently closed. It has separate drives on the gearbox (gearbox) and PTO. The forward drive has ten gears, the reverse – two.

4.Attachment system of the YuMZ-6 tractor

Tractors of the YuMZ-6 series are designed to work with a variety of mounted, semi-mounted and trailed equipment. The range of these devices is diverse; their total number makes up a specification of 258 items.

The tractor can be coupled with the following types of mechanisms:

• Agricultural implements: plows, harrows, cultivators, seeders and much more.
• General purpose equipment: welding machines, compressors.
• Trailers and semi-trailers transport various types of cargo, including containers.

To install the above equipment, a linkage mechanism is provided, attached to the brackets of the rear wall of the gearbox. The mentioned system consists of four links with three articulated points for attaching equipment. The mechanism is hydraulically equipped, which makes it possible to move the suspension axis vertically by 750 mm up and down. The attachment system is equipped with the following devices:

• A mechanism that secures the device in the transport position.
• Towing device model SA-1 with a control panel installed in the cabin.
• The power take-off shaft has a protective casing.

In the rear part there are also devices that provide connection of hydraulic, pneumatic and electrical systems of attached or trailed equipment to on-board networks. The hinged mechanism allows the operator to independently install and connect any of the above devices and operate it. This circumstance allows you to significantly increase labor productivity and eliminate the services of auxiliary workers.

5.Modifications of the YuMZ-6 tractor

The YuMZ-6K tractor was produced from 1986 to 1993.

The Yuzhmash design bureau constantly worked to modernize equipment and improve its operational and economic characteristics. In total, during the history of the model’s existence, four modifications of tractors of the described series were produced:

• YuMZ-6L. It was produced from 1970 to 1978 and differs little from the MTZ-5 in design. In terms of exterior, it is practically indistinguishable from its analogue, with the exception of the rounded radiator grille.

• YuMZ-6AL. Rolled off the assembly line from 1978 to 1986. During the modernization, the instrument panel and radiator grille were changed, and the braking system was improved.

• YuMZ-6K. Produced from 1986 to 1993. It is an industrial modification of the model and does not have a rear attachment mechanism for agricultural implements. The machine has elements for attaching a bulldozer blade and excavator equipment.
• YuMZ-6AK. Gathered from 1993 to 2001. It differed from other models in its improved cabin design, larger glass area and folding windows. A steering column adjustment mechanism has been introduced.

The YuMZ-6AK tractor was produced from 1991 to 2001.

Indices are added to the indicated model markings indicating the type of starting system of the power unit: L - starting motor and M - electric starter. All of the above modifications of YuMZ-6 tractors were actively used in the national economy. Some machines are still in use, despite their venerable age, which indicates a large margin of safety.

Electrics

A direct current of 12 volts ensures the start of the diesel engine (as well as the starting motor) remotely and the operation of electrical equipment in the cabin. There is a socket that allows you to connect light signaling equipment.

Electrical circuit diagram of the YuMZ-6 tractor equipment

1 — front lamp; 2 - spark plug; 3 — sound signal; 4 - magneto; 5 — heater electric motor; 6 — heater motor switch; 7 — windshield wiper; 8 — lock switch; 9 - fan; 10 and 25 — connecting panels; 11 — fan switch; 12 - plug; 13 — lamp switch; 14 — lampshade; 15 — “stop” switch; 16 — rear headlight; 17 — rear headlight switch; 18 — rear light; 19 — socket; 20 — direction indicator switch; 21 — turn signal switch; 22 — sound signal switch; 23 — fuel level sensor; 24 - central light switch; 26 — license plate light; 27 — magneto switch; 28 — fuse block; 29 — headlight light switch; 30 — indicator lamps; 31 — washer switch; 32 — coolant temperature indicator; 33 - ammeter; 34 — instrument panel lighting lamps; 35 — washer; 36 - generator; 37 — headlights; 38 — “mass” switch; 39 — portable lamp; 40 - battery; 41 — portable lamp socket; 42 - starter; 43 — coolant temperature indicator sensor; 44 — fuel level indicator; 45 - starter switch.

6.Features of operating the YuMZ-6 tractor

Agricultural and industrial models produced by the Southern Machine-Building Plant have proven to be extremely durable and unpretentious. The service life of the power unit before the first repair is at least 10,000 engine hours, and the labor intensity of shift maintenance does not exceed 0.0586 man-hours. With a stated service life of 10 years, there are currently examples on the move that are three times and even four times longer than this figure.

Over the entire period of operation, complete statistics of tractor failures have been accumulated. The following components and mechanisms are most susceptible to wear:

1. Power steering. The reason for failure is the failure of the NSh-10 pump or the distribution valve.
2. Clutch failure. Wear of the friction linings of the working disk due to exceeding the maximum loads.
3. Output in the cylinder-piston group due to untimely oil changes or unqualified maintenance.
4. Fuel supply system. Fuel atomization deteriorates due to wear of the injectors.
5. Loss of elasticity of springs and increase in gaps between timing parts.

Long-term and trouble-free operation of the YuMZ-6 series tractors was achieved through proper running-in, compliance with recommended operating modes and timely implementation of service procedures. The manufacturer managed to achieve an optimal combination of high technical and economic indicators and ease of learning and use

Clutch adjustment

The work flow diagram includes the following actions: 1
.
Remove the cover from the clutch hatch. It is located at the bottom of the block. The release levers are adjusted. The recommended distance between the PTO disc and the cams should be 73.5 mm. 2
.
The length of the main rod is set. The gap between the support sleeve and the levers should not exceed 4 mm. 3
.
Bolts with a 24mm head are tightened until they stop, and then loosened by 7 ratchet clicks. 4
. During operation, the clutch discs rub against each other, which leads to a violation of the initial adjustment. It is worth noting that clutch adjustment can be carried out in the field.