Motoblocks Zubr. Overview of the model range, characteristics, attachments, instructions

How does a walk-behind tractor gearbox work?

A gearbox, often called a converter, is a mechanism that processes the torque of the motor and transmits it to the power take-off shaft of the walk-behind tractor. This happens with the help of a set of gears located in a durable metal casing. The gearbox and the quality of its parts affect the service life of the unit for agricultural work. Therefore, when buying a walk-behind tractor in a store, you should pay great attention to its components, including the gearbox design.

The gearbox can be collapsible or non-dismountable. The latest models are installed on budget-type walk-behind tractors. The parts in them are cheap and cannot be repaired. In case of malfunctions, the gearbox must be replaced. During normal operation, their service life is measured in 1-2 seasons. On expensive equipment, the engine is equipped with a converter of a collapsible design. It serves well for several seasons. If individual parts break down, the failed part is simply replaced.

A converter of any type may include:

• housing (collapsible or not);
• gears and shafts;
• stars;
• belts or chains;
• bearings.

With the help of the listed parts, movements are transmitted from the motor to the mounted implements. The chain is put on the sprockets, the belt is put on the pulleys. The simplest mechanisms are equipped with a belt drive. They are also considered the weakest and most unreliable. When the torque is high, the belts slip and fly off the pulleys. But this design has a beneficial effect on the motor shaft. Belt slippage can be avoided by replacing them with toothed ones. With this replacement, the pulleys also need to be replaced.

Attachments

When working with Zubr products, proprietary attachments and homemade products are used. Standard products include a horizontal rotary cultivator. The cultivator is rigidly attached to the rear cover of the gearbox housing. The drive is carried out by a chain mechanism. The working rotor has removable teeth. The plow is adjusted using the rear wheel mounted on a screw support. The cultivator provides a plowing depth of dry soil up to 120 mm, wet soil - up to 140 mm.

The mechanical mower Zubr is equipped with a drive from a pulley or a separate shaft mounted on the gearbox. Based on the type of working element, mowers are divided into rotary and segmental. The segment installation allows the grass clippings to be folded into a neat strip, reducing the time required to collect hay.

To simplify the control of the walk-behind tractor, an adapter is used, which is a steel frame with 2 wheels and a seat. The wheels are mounted rigidly, and there is a platform for the operator’s feet in front of the seat. The connection between the adapter and the walk-behind tractor is carried out using a hitch, which ensures the mobility of the parts when turning. The seat is height adjustable, and there is a control lever for attachments on the side. It is possible to install control pedals and a steering wheel.

To improve cross-country ability and reduce slipping, metal wheels with developed lugs are used. The number and shape of lugs vary depending on the type and condition of the soil.

What types of gearboxes are there for a walk-behind tractor?

Gearboxes are divided into types:

• angular;
• downward;
• gear;
• worm;
• chain;
• combined.

All of them find their application on walk-behind tractors of various types.

Angular

The angular gearbox for the walk-behind tractor ensures the coupling of the engine with the transmission and attachment mechanism. Another device is also used, if modified. The corner device consists of the following parts:

• flange;
• flange mounting;
• bearing;
• frame;
• pulley;
• belt;
• steel washer;
• pulley fastening;
• key;
• rotor shaft.

You can make this device yourself. Before work, it is necessary to take into account the conditions in which he will work. These are radial and axial loads at the ends of the shafts. The load depends on the type of lubricants and temperature. It is best to choose a factory-made case. Bearings of the required size are selected for the shaft.

Downward

A reduction gearbox for a walk-behind tractor, either self-made or industrially manufactured, is designed to increase the power of an agricultural unit. This may be necessary when operating the walk-behind tractor on sandy soil, when the wheels begin to slip. It is used on gasoline and diesel vehicles equipped with an air cooling system.

You can reduce the number of revolutions and increase the power of the drive mechanism using reduction gearboxes, which are sometimes called creepers for a walk-behind tractor. They are considered the most reliable for operating a diesel or gasoline air-cooled walk-behind tractor. When the unit is operating, the number of revolutions decreases. This allows you to use the walk-behind tractor for particularly difficult work, for example, plowing heavy soil or harvesting potatoes using a potato digger.

Gear

A gear converter with a differential is used in heavy-duty walk-behind tractors. It is well suited to engines with a vertical crankshaft. The gearbox produces little noise during operation and has high performance. It is capable of functioning in straight and angular patterns. Gears are used both bevel and cylindrical. The device requires the constant presence of oil in the crankcase, but this feature is compensated by its high power.

On heavy units, the gear converter is often equipped with a gearbox. This transmission allows the walk-behind tractor to move in reverse. Reverse occurs during reverse rotation of the gears in the housing. This is achieved by changing the position of the lever outside the housing.

Gear reducer is the best choice for heavy agricultural machinery. An engine equipped with this mechanism runs longer than with a worm version.

Worm

Worm gearboxes are widely used in mini-tractors and walk-behind tractors. This model has gained popularity due to its long period of trouble-free operation and high reliability. The worm-type device has a reverse, allowing the unit to move in reverse. A distinctive feature of this converter is the presence of a special screw and worm wheel. The thread profile on the parts is trapezoidal. They are made from high-strength materials.

The screw can have a four-start thread or a two-start thread. It matches the thread on the gear. The teeth on high-quality parts are made of anti-friction steel. The efficiency of the device is high. Its advantages:

• the gearbox allows you to extend the service life of the engine;
• creates little noise during operation;
• The device consists of only 2 parts;
• has a large gear ratio;
• has a smooth ride;
• high self-braking effect.

All positive qualities appear with precise assembly and adjustment of the mechanism.

Chain

A chain device must have a chain in its design. Sometimes it occurs not just one, but in several pieces. The gear chain is put on the sprockets and ensures their rotation. The device is easy to use, has a reverse function and a high degree of reliability. The operating principle is similar to a belt mechanism. Changing the gear ratio is easy by changing the sprocket sizes. They work like a bicycle, but in reverse: the small one is the driving sprocket, and the large one is the driven sprocket.

Reliability of operation is ensured by the quality of the metal of the sprockets and the strength of the chain. When making your own gearbox, you should use motorcycle sprockets; they are much stronger than bicycle sprockets. The design of the product is simple and reliable, it has a reverse function. The chain requires constant lubrication and tightening. Its rupture is a common cause of gearbox failure. To repair, you need to change the chain.

Combined

The combined gearbox combines gear and worm, worm and cylindrical gears. It can be single-stage or multi-stage. The single-stage mechanism has a gear ratio of up to 7. The body is made of cast iron or welded aluminum. Two-stage devices have a gear ratio of up to 40, three-stage - up to 150.

All of them are designed to change the speed of rotation of the engine shafts and the power take-off shaft. All types of gears are placed in a single housing. The combined mechanism is the most practical. Despite its small size, it has high quality and low cost.

Comparison with other manufacturers

Before deciding where to buy a Zubr walk-behind tractor, you need to compare its characteristics with other representatives. Let's look at the distinctive features using the Centaur walk-behind tractor as an example.

Characteristic features of the mini-tractor:

• equipped with a 4-13 hp engine;
• diesel and gasoline fuel options available;
• it is possible to attach additional mechanisms, most of which are produced by the same company;
• the cost of the Centaur is 16,000 - 65,000 rubles, while the Bison costs 21,000 - 67,000 rubles.

Creeper

The traction of the wheels of a tillage machine with the soil can be enhanced if you use lugs or a creeper for a walk-behind tractor. The creeper is one of the mounted devices. It makes it possible to reduce the speed of the agricultural unit and increase traction force along with torque. An analogue of a gearbox operates using a chain and sprockets on the shafts. If desired, this device can be made by hand. Parts are used from other equipment.

Each considered converter has its own disadvantages. To reduce their number to a minimum, you should try to make the device yourself. A homemade item can be of higher quality and easier to use than a purchased item.

Owner reviews

Evgeniy, Smolensk region.

A heavy Zubr walk-behind tractor with a diesel engine, equipped with a milling cutter and a plow, is in operation. Driving a powerful walk-behind tractor with a lot of weight requires physical effort; careless movement throws the driver out from behind the wheel. The soil is plowed quickly and the soil is well loosened. When driving on the road, a walk-behind tractor complete with a trolley accelerates to 20-25 km/h.

Alexander, Belarus.

The Zubr equipment with a gasoline power unit is used. The engine is equipped with an electric starter starting system, but the engine can also be easily started using a manual device. The kit included a trailer and a rotary mower. The engine power is sufficient to operate this equipment. The disadvantage is high fuel consumption, but the engine starts easily in the cold season.

Roman, Tula region.

The walk-behind tractor was purchased for plowing a plot of land with clay soil. Before starting work, the threaded connections were tightened; the assembly quality was poor. Plowing was carried out in several passes, with a gradual increase in depth. The Bison is not suitable for such work.

How to make a gearbox for a walk-behind tractor with your own hands

A homemade gearbox for a walk-behind tractor requires preparation of tools for manufacturing. For fruitful work you will need:

• screwdrivers of different sizes;
• hacksaw for metal;
• pliers;
• bench vice;
• welding machine;
• hammers of different weights;
• rubber for gaskets;
• drill with drills.

Some other tools may be required as you work. From the materials you need to prepare shafts and bearings, sprockets and chains, belts and gears. You can use a caliper to measure parts. Before work you need to complete the simplest drawings.

Preparation

So, the tools and sketches are ready, you need to prepare the material for welding the body or take a ready-made one. You can weld from pieces of stainless steel. The prepared gears should fit freely into the finished housing. They can be borrowed from an old chainsaw. The Friendship brand or any other is suitable. The saw must be carefully disassembled and the entire gears along with the shafts removed. They are cleaned and washed, then sized according to the gear ratio.

When calculating the gear ratio, you should take the number of idle revolutions of the engine crankshaft as a basis and add 10% to it.

With any design of the product, distortions between the parts of the driven and driving parts must not be allowed.

Bearings should also not be replaced with bushings. When disassembling an old saw, you need to remember this.

Assembly

When assembling the product, the parts are carefully inserted into place in the body and rotated. The housing must be sealed tightly. This will protect the parts from dust and dirt. Oil seals are installed on the shafts. Lubricant is poured inside the housing. The homemade device is connected in the same way as a standard gearbox. To test it, start the engine and roll it on the ground. The parts need to get used to each other a little.

Engine Specifications

The diesel engine for the Zubr 12 model has the following characteristics:

Be sure to read: Characteristics of the Agro walk-behind tractor, conversion possibilities

Minitractor from the Zubr walk-behind tractor

How much oil to pour into the walk-behind tractor gearbox

When operating the walk-behind tractor, it is necessary to maintain a constant oil level in the gearbox. If this simple rule is not followed, lubricant residues may boil and jam the parts. Only high-quality oil is poured. Even with constant maintenance of the level, breakdowns occur. During chain transmission, the chain breaks or is pulled out. If traces of oil appear on the outside, this is a sign of leaking seals. Worn parts require replacement with similar ones. It is better to purchase them from a reputable manufacturer.

The gearbox ensures uninterrupted operation of the walk-behind tractor, extends its service life and increases the efficiency of use of the unit. A good helper in this matter is to lubricate its parts. Transmission oil is poured in for lubrication. Its possible brand is ZIC 10W40, Super T-3. The oil level is determined in this way:

• you need to take a wire approximately 70 cm long instead of a probe and bend it into an arc;
• insert into the filling hole until it stops;
• pull the homemade dipstick back;
• the wire should be oiled to a length of about 30 cm.

This level is considered to be the norm. If there is little oil, you need to add it to the norm. In a purchased gearbox, the level must be indicated in the instructions. A Chinese walk-behind tractor can be sold without oil.

Advantages and disadvantages of Zubr 12

In their reviews, the owners of the walk-behind tractor highlight its reliability as a key advantage. This reliability is ensured by timely and complete maintenance of the motor. For the R195N diesel engine, the engine oil must be changed every 250 hours of operation. Similar work on changing the oil in the transmission of a walk-behind tractor must be performed after 150 hours of operation. Other advantages include:

• versatility;
• power;
• compactness;
• permeability;
• maneuverability;
• maintainability and ease of maintenance;
• low noise level;
• affordability;
• ease of transportation.

In addition to the positive qualities, you can also find a list of disadvantages :

• lengthy process of installing additional equipment;
• periodic occurrence of difficulties when shifting gears.

But at the same time, the vast majority of owners clearly state that the advantages of the walk-behind tractor clearly outweigh its disadvantages.

Analogues model include the following heavy walk-behind tractors:

• Grillo G 107D;
• MB-12DEL;
• Crosser CR-M12E
• Centaur MB 1013D;
• Scout GS 101 DE.

Types of breakdowns and ways to fix them

Most often the motor breaks down. In the instructions for repairing the engine of a Zubr walk-behind tractor, you will find almost all the answers and all the solutions to this issue. Let's talk about some of the causes of walk-behind tractor engine failures and ways to eliminate them.

The motor does not reach maximum power. Try the following:

• clean the carburetor;
• blow out the fuel hose;
• check the crankcase cuff. It may be damaged or worn out. Replace it if necessary;
• check the muffler and cylinder. They accumulate fumes from exhaust gases, which can clog the passages. Everything needs to be cleaned well;
• Check the air filter, which may also be clogged.

It also happens that you simply stored your unit in a damp and cold room. You need to turn it on and let it work. Most likely, after some time the problem will go away on its own.

The motor does not turn on. Do the following:

• if it is uneven, level it;
• check the spark plug;
• Magneto failed. A part needs to be replaced;
• if fuel does not flow into the carburetor, you need to clean the fuel system;
• check the filter and then replace or clean it;
• check the outlet hole in the gas tank. It may be clogged.

The engine runs intermittently and switches off periodically. Do the following:

• if your unit does not turn on after winter, just warm it up;
• The magneto may need to be replaced;
• spark plug contamination. It needs to be either cleaned or completely replaced.

Other problems may also occur. For example, a walk-behind tractor pulls to the right or left. First of all, check the tire pressure, and if it is different, equalize it in both wheels. After that the pulling will stop.

If white smoke suddenly comes out of the exhaust pipe, replace the fuel with a higher quality one without impurities. Many manufacturers are guilty of this. Also check how level your car is, as oil can spill and get onto the valve, where it starts to burn.

The starter started making strange squealing sounds. There may be too much grease on the balls. You need to remove excess from the balls and on the ratchet.

After several pops occurred, floating revolutions began to appear. First of all, check the fuel level in the tank; it may be insufficient. The power supply system may not be able to cope with its tasks. Debris may have gotten under the needle valve. Everything needs to be checked, cleaned, and the air filter changed if necessary.

Motoblock "Zubr" JR-Q79

The unit processes heavy soils and virgin soil in areas of up to 3 hectares.
Due to its heavy weight, the walk-behind tractor cannot boast of great maneuverability. But with the ability to lock the differential, it is easy to deploy on the spot. You can use various attachments and easily select the necessary spare parts and components. The walk-behind tractor can be repaired with your own hands.

Specifications:

• Engine with a power of 10 hp. With.;
• Fuel tank – 6 liters;
• Plowing width – up to 90 cm;
• Plowing depth – up to 18 cm;
• Gearbox – two forward and one reverse speed;
• Availability of mechanical and electric starter;
• Unit weight – 260 kg.