DIY centrifugal clutch for walk-behind tractor

AUTOMATIC CENTRIFUGAL CLUTCH

Once upon a time, while studying at the Moscow Automotive Institute (MAMI), I, like all other students, had to do course projects. However, it was not very interesting for me to construct “something theoretical”, mostly abstract and not needed by anyone, so I always tried to get an assignment to develop a real unit or unit that could be manufactured and then used in life. One such topic was the automatic dry clutch for small agricultural machines. And now, many years later, when I had the need to urgently replace the V-belt drive of a household mini-tractor with a more reliable chain drive, I suddenly remembered that long-standing work of mine. It took a clutch! I rummaged in an old portfolio, found the institute’s sketches, modified them a little and took up the tools. This time I did not calculate any theory, only “pure practice”, the main criteria of which were the use of ready-made basic parts, manufacturability, available in conditions “almost on the knee,” and the speed of production. All work took one daylight.

The automatic centrifugal dry clutch is installed directly on the crankshaft of the engine (in this case, the Honda GX engine, which has many analogues) without any additional modifications. The structure does not require any adjustments or special maintenance. It is collapsible and has good maintainability and can be used in transmissions not only of motoblocks and tractors, but also on snowmobiles, karts, motor scooters, small cars.

The standard clutch from the Honda Dio scooter was taken as a basis: its clutch plate was used without changes and a drum that was machined under the original hub. This bushing and flange (positions 5 and 12 on the assembly drawing) are made of steel 45. The drive sprocket of a motorcycle “Minsk” (“Voskhod”) is taken as a drive. a common and affordable part. It was previously thermally tempered, machined (machined) to fit the size of the bushing seat, after which it was hardened. The sprocket is pressed onto the bushing and fixed by welding. In principle, this assembly can be made as a single piece, but the labor intensity would be much higher, so I did not bother with complications.

centrifugal, clutch, walk-behind, tractor

The appearance of the unit installed on a homemade mini tractor

The modified drum is also pressed onto the bushing and secured by welding. The bearing is used light series 6006. In the bushing it is fixed against lateral displacement by punching. The pulley was taken from the auxiliary equipment (generator or hydraulic pump) belt drive previously installed on the tractor. For particularly severe operating conditions, instead of a pulley, it is possible to install an additional bearing on the engine shaft, which serves to unload the standard bearing of the internal combustion engine crankshaft. If you refuse to use a pulley, then the clutch will be very compact, within the dimensions of the engine shaft.

Centrifugal clutch. Assembly drawing: 1. pulley; 2. bearing 6006; 3. Honda Dio clutch plate (assembled unchanged); 4. Honda Dio drum; 5. bushing; 6. motor shaft (diameter 19 mm); 7. key; 8. washer; 9. screw М8х35; 10. washer; 11. sprocket (15 teeth from the motorcycle “Minsk” or “Voskhod”); 12. flange; 13. bushing

Oddly enough, but the most difficult stage in my garage conditions was the manufacture of a keyway on the flange (position 12). I had to think not only about the design, but also about the technology. For this, a stock with a transitional fit was machined. It was inserted into the flange and, using a drilling machine (not a hand drill!), A hole with a diameter of 5 mm was made at the junction of these parts. Then, with a flat file (its narrow side edge), the semicircular groove was brought to the desired rectangular shape.

A similar operation was carried out with the driven sprocket of the drive.

Automatic centrifugal dry clutch

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The running tests of the clutch have shown good results. The four-wheel drive tractor confidently moved through the spring softened snow in fourth gear. The speed range varied from 3 to 15 km / h, while the clutch housing remained cold. The moment of its triggering was also acceptable.

It was not without testing for maximum load: I buried the tractor in a tree with the bridges and locks on. the wheels slipped confidently, and the heating of the clutch remained within acceptable limits. And demonstrating the device to neighbors and friends, I laugh. I say that once again, now in practice, I defended my old course project. In a word, it was not in vain that I studied!

Types and description of clutch mechanisms for motoblocks

Depending on the design features of motoblocks, agricultural units can be equipped with the following types of clutch:

By their type of friction, clutch mechanisms are divided into dry, as well as devices operating in an air environment or in a bath of engine oil. Depending on the initial start-up mode, there is a non-permanently open and permanently closed clutch on the market.

Why does a walk-behind tractor need a clutch?

Connects and opens the engine crankshaft and the input shaft of the gearbox during sudden stops;

  • Extinguishes fluctuations when switching speeds;
  • Makes starting and braking smoother and more enjoyable.
  • Another important task is the contactless connection of the gears and the improvement of the wear resistance of the entire transport unit. Therefore, it is so important to choose the optimal clutch model specifically for your own. Let’s consider the most common options.

    All about the clutch for the walk-behind tractor: we set out in order

    The clutch of the walk-behind tractor is an important element of the transmission, through which the crankshaft of the engine transmits torque to the gearbox mechanisms. With the help of this part, during gear shifting, the engine and gearbox are disconnected. It is due to the participation of the clutch that the uniaxial tractor starts smoothly from the spot, and also stops without completely shutting down the motor.

    general information

    The clutch is based on the action of the friction clutch (sliding friction force). This transfer component is intended to:

    • broadcast torque ;
    • suppression of torsional vibrations;
    • smooth displacement;
    • bumpless connection;
    • connection and short-term disconnection of the internal combustion engine from the gearbox;
    • disconnecting the transmission from the flywheel.

    The mechanism allows you to temporarily disable the power transmission of the unit engine and the engine crankshaft. In addition, the single-axle tractor starts to operate with a jerk-free clutch. Of great importance to agricultural machinery while driving, clutch allows you to move around (although it can be done without it, it is very difficult).

    The centrifugal clutch has proven itself as a reliable transmission component. It has found its way into automatic transmissions. Its main operational elements include: flywheel, pulley, hub with key and locking slot, flange, housing, bushing, bearing, circlip.

    The differential, which is directly related to the clutch, also plays an important role. He was entrusted with the tasks of improving the maneuverability of super-powerful super-powerful installations and ensuring a smooth ride. Clutch and the differential in “symbiosis” regulate the rotation of the wheel part of the motor unit at different speeds. In addition, the power transmission mechanisms are equipped with wheel locking functions. However, in some models, the differential is replaced by a special device that disables one wheel when driving.

    On modern models of the engine block, a friction clutch is usually used. It is installed between the gearbox and the engine. When the driven elements of the friction clutch are closely connected with the input shaft of the gearbox (or another, after the clutch, the transmission unit), and the leading. with the engine crankshaft. As a rule, the leading and rear elements are made in the form of round flat discs, sometimes they are made with a change in cone (for example, BSU-735 and Kataisi Super-600 units) and a shoebox (Gutbrod, Mepol-Terra).

    In the case of the manufacture of these working elements in the form of pulleys with a V-belt, tension rollers are additionally introduced, allowing you to set their position, the degree of tension from the belt control panel, in order to disconnect and connect the engine to the transmission. to the menu

    What to choose?

    Many experts agree that a single-plate dry clutch with a friction clutch is the best option for most vehicles, including motor vehicles. It transmits maximum torque, is durable and easy to operate.

    Homemade Clutch. Power Loom / Embrague Casero. Telar Mecánico

    Clutch with a walk-behind tractor: types, device, principle of operation

    As an integral part of the transmission, the walk-behind tractor clutch performs the function of transmitting torque from the crankshaft to the gearbox (gear shaft). At the same time, during gear changes, the power plant and the transmission are disconnected. Thanks to this mechanism, a single-axle tractor begins to move mechanically and stops without stopping the engine.

    If the conceived design of factory motorcycles does not provide for the implementation of a clutch, you can assemble it yourself.

    Features of the design of the clutch for a uniaxial tractor

    The clutch for a walk-behind tractor, as in any other agricultural type equipment, consists of the following parts:

    • direct control unit. The release lever is connected to the pressure disc by a pedal wedge and rods;
    • the leading node. The bearing reduces friction, during rotation around its axis the levers do not touch;
    • driven components. The spring returns all mechanisms to their original position. The layering is pushed away from the levers at a distance that is necessary to turn off the technique.

    The clutch design is not very complicated, therefore, if necessary, you can repair faults yourself.

    How the clutch works

    A clutch for a walk-behind tractor consists of several important elements:

    • Control devices;
    • Leading element;
    • Driven parts.

    The driving part consists of the end face of the engine flywheel and the pressure plate. The disc rotates with the attached flywheel. At the same time, the disc can also move axially in relation to the flywheel. Between these two elements is the driven disc, which is located on the driven shaft. Spring elements in the form of cylinders are located around the perimeter of the pressure plate. The function of the springs is based on the compression of the disc they support. In this case, the other end of the springs contacts the casing. Thus, the springs maintain the clutch for the walk-behind tractor in a constant on state.

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    The control mechanism is made of release levers connected to the body of the pressure discs by means of rods with a deflector and a pedal. Disengaging the clutch, the owner of the walk-behind tractor engages the clutch cable, which transmits force to the release levers. When the springs are compressed, the levers move the driven disc away from the pressure plate, which disengages the clutch.

    The bearing reduces friction by preventing the stationary leg from touching the rotation levers. Most models of walk-behind tractors are equipped with three levers located at an angle of 120 degrees in relation to each other. Each clutch lever is returned to its original position by a spring. In this case, the layering moves to the distance required to turn off the levers. If this distance is not reached, then the clutch starts to slip.

    Clutch functions in the design of the walk-behind tractor

    The clutch operation is based on the action of the friction clutch. This transmission element performs several important functions, among which it stands out:

    • Uninterrupted transmission of torque;
    • Suppression of torsional vibrations;
    • Smooth gear shifting;
    • Shockless gear connection;
    • Connecting and disconnecting a gearbox with an internal combustion engine;
    • Disconnecting the Transmission from the Flywheel Assembly.

    The clutch device makes it possible to briefly disconnect the engine crankshaft and the power train of the machine. Thanks to the clutch, the vehicle starts and stops moving smoothly and without jerking.

    Walk-behind tractor clutch. device, principle of operation and do-it-yourself manufacturing

    The clutch of the walk-behind tractor is an important element of the transmission, through which the crankshaft of the engine transmits torque to the gearbox mechanisms. With the help of this part, during gear shifting, the engine and gearbox are disconnected. It is due to the participation of the clutch that the uniaxial tractor starts smoothly from the spot, and also stops without completely shutting down the motor.

    How to make a clutch mechanism with your own hands?

    The clutch on a uniaxial tractor works on the principle of increased friction of the components, so rapid wear cannot be avoided. In this case, you should try to make the mechanism yourself. The homemade clutch design will be composed of:

    • the input shaft of the gearbox and the flywheel of the Moskvich car;
    • hub and steering knuckle from Tavria;
    • B-profile;
    • Two grooved driven pulley;
    • Crankshaft from GAZ-69.

    Centrifugal clutch. design and benefits

    This kind of element should be distinguished from other structures due to its reliability and durability. It is used in automatic gearboxes. Its design consists of the following elements:

    • Flywheel;
    • Pulley;
    • Hubs with locking groove and key;
    • Flange;
    • Bushings;
    • Casing;
    • Bearing;
    • Retaining ring.

    One of the most important roles is played by the differential device associated with the centrifugal clutch. It helps improve vehicle maneuverability and smoother cornering.

    Together with the clutch, the differential regulates the rotation of the wheels of the walk-behind tractor at different speeds. over, the power transmission mechanisms work together to act as wheel locks. In some models of equipment, instead of a differential, a special device is installed that locks one of the wheels of the walk-behind tractor at the command of the driver.

    modern models of equipment are equipped with a friction clutch. It is mounted between the motor and the gearbox. In this design, the driven parts are closely connected with the input shaft of the gearbox, and the leading parts are closely connected with the crankshaft of the engine. In most cases. and the driving and driven elements are made in the form of flat circular discs, or in the form of a cone. Just like the centrifugal clutch, the friction clutch is activated by manipulating a separate handle.

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    Subsequent work on the assembly of the mechanism is as follows:

    • First you need to grind the crankshaft so that it does not cling to other elements of the walk-behind tractor;
    • We put the standard hub of the walk-behind tractor on the shaft;
    • Next, on the shaft, it is necessary to groove a place for the bearing. This operation should be performed as accurately as possible so that the bearing fits perfectly on the shaft. As a result, the hub should fit without any gaps, and the pulley should scroll;
    • Then turn the crankshaft over and do the same on the back of it;
    • Next, drill 6 holes in the pulley with a drill with a 5mm drill bit. The distance between them must be the same. Since 10mm bolts will be used, holes must also be drilled on the back of the wheel driving the drive belt;
    • Next, install the pulley on the flywheel, and tighten both parts with a bolt. Then mark the drill spots on the flywheel so that they line up with the 6 holes in the pulley;
    • Remove the pulley and drill holes in the flywheel;
    • After that, put on the pulley again and securely tighten the structure with bolts;
    • Grind the inner surface of the crankshaft and flywheel so that they do not hit each other.

    The finished structure can be installed on a regular place in the walk-behind tractor. Do not forget to connect the cables, leading them as far as possible from the friction elements.

    Clutch on a uniaxial tractor: types, device, principle of operation

    As an integral part of the transmission, the clutch of the walk-behind tractor performs the function of transferring torque from the crankshaft of the motor to the gearbox (gearbox shaft). With its help, during gear shifting, the power plant and the gearbox are disconnected. Due to this mechanism, a single-axle tractor or a motorboat moves off and stops without turning off the motor.

    If the conceived design of factory-made motor vehicles does not provide for a clutch, it can be assembled independently.

    General information

    The clutch is based on the action of the friction clutch (sliding frictional force). This transmission component is intended for:

    • transmission of torque;
    • damping torsional vibrations;
    • smooth gear shifting;
    • shockless gear connection;
    • connection and short-term disconnection of the connection of the internal combustion engine with the checkpoint;
    • disconnecting the transmission from the flywheel.

    The mechanism makes it possible to temporarily disconnect the power transmission of the walk-behind tractor and the crankshaft of the motor. In addition, the single-axle tractor can be operated without jerks by means of the clutch. Being of great importance for agricultural machines when driving, the clutch allows you to get under way (although without it it is possible to do this, it is very difficult).

    The centrifugal clutch has proven itself as a reliable component of the transmission. It has found its application in automatic transmissions. Its main working elements include: a flywheel, a pulley, a hub with a key and a locking groove, a flange, a casing, a bushing, a bearing, a circlip.

    The differential, which is directly related to the clutch, also plays an important role. It is tasked with improving the maneuverability of heavy-duty motoblocks and ensuring smooth turning. The clutch and differential in “symbiosis” regulate the rotation of the wheel part of the walk-behind tractor at different speeds. In addition, the power transmission mechanisms are equipped with wheel locking functions. However, in some models, the differential is replaced by a special device that disables one wheel when driving.

    On modern models, a single axle tractor usually uses a friction clutch. It is installed between the gearbox and the engine. With a friction clutch, the driven elements are closely connected with the input shaft of the gearbox (or another transmission unit following the clutch), and the leading ones with the engine crankshaft. As a rule, the leading and driven elements are produced in the form of round flat discs, sometimes they are made in a conical variation (for example, motor-blocks BChS-735 and Kataisi Super-600) and shoe (Gutbrod, Mepol-Terra).

    In the case of the production of these working bodies in the form of V-belt drive pulleys, tension rollers are additionally introduced, allowing them to set their position, the degree of tension from the belt control rod, and to disconnect and connect the engine to the transmission. to the menu

    1.1 Design and principle of operation

    The friction-type clutch consists of:

    • control mechanism;
    • leading part;
    • driven elements.

    The drive end is formed from the end face of the motor flywheel and a pressure plate that rotates with the flywheel. However, the disc has the ability to move in the axial direction relative to the flywheel. Between them is the driven disc, its hub is located on the splined driven shaft. Coil springs are placed around the circumference of the pressure plate, installed with preliminary compression.

    The role of the springs is to press the pressure disk, into which they abut with one end, and the other against the casing, together with the driven end surface of the flywheel. As a result of these actions, the clutch arrives constantly in the engaged state.

    The control mechanism includes release levers, which are connected to the pressure plate by rods and a branch with a pedal. When disengaging the clutch, the operator sends a force from the pedal or lever using a fork or cable to the release levers through a release bearing with a release bearing. With their outer end bolted to the pressure plate, the levers during the compression of the springs move the driven discs away from the pressure plate, thereby disengaging the clutch.

    The bearing reduces friction by eliminating contact between the stationary leg and rotating arms. Typically, there are three levers in a set, placed at an angle of 120 degrees to each other. By means of a spring, the parts of the control mechanism are returned to their original position. The branch is separated by the amount of clearance from the levers required to completely disengage the clutch. If this distance is not observed, the clutch slips and the friction linings wear out. When the clearance exceeds the required distance, the clutch will not completely disengage. to the menu

    Clutch types, their features

    Depending on the design characteristics of motor vehicles, the clutch for a walk-behind tractor can be of the following types:

    • frictional (discussed above);
    • electromagnetic;
    • hydraulic;
    • centrifugal;
    • belt;
    • one-. two-disk;
    • multi-disc.

    By the type of friction, the considered mechanism is classified into wet, operating in an oil bath, and dry, operating in an air environment. In accordance with the mode of inclusion, a permanent closed and non-permanently closed clutch are distinguished.

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    Centrifugal works due to the following working elements: clutch cable, transmission input shaft, flywheel, clutch lever, release bearing, handle, driven disc, engagement lever, stem fungus, lock washer, shutdown fork. Centrifugal devices have not found widespread use due to their tendency to slip, which is characteristic under loads, and wear of friction surfaces.

    With a hydraulic system, through the connecting rod, when the pedal is depressed, the movement is transmitted to the piston, pushing the hydraulic fluid through a special channel. The piston, under the action of the pressure of the working medium, acts on the lever through the connecting rod. With a spring, it returns to its original position.

    The multi-disc and single-disc operating principles practically do not differ from each other. The advantages of the first are based on the small size of the friction discs, smooth engagement of the clutch. The disadvantages are worse cooling conditions, problems in obtaining the purity of the inclusion. Two-disc mechanisms are installed in connection with the high power of the power unit, the need to transmit increased torque, to increase the service life.

    The belt-driven clutch, which provides the transmission of torque from the motor to the gearbox, is considered one of the first and is inferior to the above mechanisms, because has a number of disadvantages: a high level of wear, unreliability, low efficiency, impracticality when working with powerful engines. to the menu

    2.1 Retrofitting the clutch

    Since the principle of operation of the device provides for serious friction of the component parts, natural wear cannot be avoided. You can make a clutch for a uniaxial tractor with your own hands, however, owners of motorized machines who do not have experience in plumbing are not recommended to perform this operation.

    Consider an example of creating a mechanism for a heavy walk-behind tractor. The basis is the flywheel and the input shaft of the Moskvich car box, a steering knuckle with a hub from Tavria, profile B, a driven pulley for two strands and a steel billet as a crankshaft (suitable from GAZ-69). A homemade product begins with turning a steel billet on a lathe in order to fit a hub onto the resulting false shaft. After the pulley lands on the sharpened shaft, you should grind the seat in diameter on the inner ring of the pulley under the thrust bearing, which should “sit” perfectly.

    If the hub fits without gaps, and the pulley scrolls, this is a sign of a correctly completed task. Turn the part over and do the same on the back side. In the next step, use a drill and drill (5 mm) in the pulley to make 6 holes equidistant from each other. Since the bolts will be 10 mm, on the reverse side it is necessary to drill out the holes of the wheel that gives movement to the drive belt with a 12 mm drill.

    A pulley is installed on the flywheel, a hole should be made with the same drill and both parts should be tightened with a bolt to fix. While the pulley is on the flywheel, mark the flywheel through the holes you made earlier. Remove your pulley and drill all 6 holes.

    Using bolts (10 mm), tighten the structure, the thread without a head should be 60 mm. Grind the crankshaft inside with a blank. To prevent the flywheel from hitting, it is also necessary to grind its surface, and then center it along the landing hole.

    It may be necessary to slightly trim the inner plane of the flywheel together with the pulley on a lathe. The metal layer is removed no more than 1 m. Having previously seated the flywheel on the shipment, check the runout of the planes, it should not exceed 0.1 mm. Ultimately, it remains to mount the basket on the flywheel. to the menu

    Purpose and varieties

    The clutch carries out an inertial transfer of torque from the crankshaft to the transmission gearbox, provides a smooth start of movement and gear shifting, regulates the contact of the gearbox with the motor of the walk-behind tractor. If we consider the design features, then the clutch mechanisms can be divided into:

    • friction;
    • hydraulic;
    • electromagnetic;
    • centrifugal;
    • single, double or multi-disc;
    • belt.

    According to the operating environment, a distinction is made between wet (in an oil bath) and dry mechanisms. According to the switching mode, a permanently closed and non-permanently closed device is divided. According to the way in which torque is transmitted. in one stream or in two, one- and two-stream systems are distinguished. The design of any clutch mechanism includes the following elements:

    • control node;
    • leading details;
    • driven components.

    The friction clutch is the most popular among farmers-owners of motoblock equipment, because it is easy to maintain, high efficiency and long continuous operation. The principle of operation is the use of friction forces that arise between the contacting faces of the driven and driving parts. The leading components work in a rigid connection with the engine crankshaft, and the driven ones. with the main shaft of the gearbox or (in its absence) with the next transmission unit. The elements of the friction system are usually flat discs, but in some models of walk-behind tractors a different shape is implemented. shoe or conical.

    In a hydraulic system, the moment of movement is transmitted through a fluid, the pressure on which is provided by a piston. The piston is returned to its original position by means of springs. In the electromagnetic form of the clutch, a different principle is implemented. the movement of the system elements occurs under the action of the forces of electromagnetism.

    This type refers to permanently open. The centrifugal type of clutch is used in automatic gearboxes. Not very common due to rapid wear of parts and long slip times. The disk type, regardless of the number of disks, is based on the same principle. Differs in reliability and provides smooth start-up / shutdown of the unit.

    The belt clutch is characterized by low reliability, low efficiency and rapid wear, especially when operating with high-power motors.

    Clutch adjustment

    It should be noted that when working, certain recommendations must be followed in order to avoid premature breakdowns and unnecessary problems arising from improper handling of equipment. The clutch pedal must be pressed and released smoothly, without sudden movements. Otherwise, the engine may simply stall, then you will need to spend extra time and effort to start it again. During the operation of the walk-behind tractor, the following problems associated with the clutch mechanism are possible.

    • When the clutch is fully depressed, the technique begins to accelerate sharply. In this situation, just try to tighten the adjusting screw.
    • The clutch pedal is released, but the implement does not move or does not move at an adequate speed. Loosen the adjustment screw slightly and test the ride of the motorcycle.

    In case of strange noises, crackling, knocking coming from the area of ​​the gearbox, stop the unit immediately. The most common reasons for this are low oil levels or poor quality. Before you start working on the walk-behind tractor, be sure to check the presence and amount of oil. Change / add oil and start the unit. If the noises continue, stop the single-axle tractor and have a specialist inspect your equipment.

    If you have problems with shifting gears, test the clutch, adjust it. Then inspect the gearbox for worn parts and check the shafts. splines may have worn out.

    Clutch mechanism classification

    According to the available design features of agricultural machines, they can be equipped with clutch mechanisms of the following types:

    • friction-type clutch. this kind of mechanism is in the highest demand among buyers. Its main advantages include ease of use and self-service, as well as high productivity and long service life;
    • centrifugal clutch. this mechanism is not so popular due to their tendency to slip for a long time. The centrifugal clutch is equipped with a large number of rubbing parts that are susceptible to increased wear. In this regard, the centrifugal clutch is not in such high demand among farmers;
    • belt-type clutch. among the main disadvantages of such units are low performance and extremely low reliability. The belt clutch of the walk-behind tractor quickly deteriorates, especially if the agricultural unit is equipped with a powerful engine;
    • disc-type clutch. the design of an agricultural machine can include a single-disc or multi-disc mechanism. The disc clutch on walk-behind tractors is completed with reliable spare parts, the correct arrangement of which ensures smooth start-up of the walk-behind tractor used on the farm.

    This kind of classification allows each of the buyers to choose a mechanism that is optimal in design and characteristics for their walk-behind tractor.

    How to do it yourself?

    The clutch for a uniaxial tractor can be made or changed independently, if you have experience in locksmith work. For the manufacture or replacement of a homemade mechanism, you can use spare parts from cars or from a scooter:

    • flywheel and shaft from the Moskvich gearbox;
    • hub and rotary cam from Tavria;
    • pulley with two handles for the driven part;
    • crankshaft from “GAZ-69”;
    • B-profile.

    Before you start the process of installing the clutch, carefully study the drawings of the mechanism. The diagrams clearly show the relative position of the elements and the step-by-step instructions for assembling them into a single structure. The first step is to sharpen the crankshaft so that it does not have contact with other parts of the system. Then place the motoblock hub on the shaft. Then prepare a groove on the shaft for the release bearing. Try to do everything carefully and accurately so that the hub sits tightly on the shaft, and the pulley with handles rotates freely. Repeat the same operation with the other end of the crankshaft.

    Insert a 5 mm drill into the drill and carefully drill 6 holes in the pulley, at equal distances from each other. On the inside of the wheel connected to the drive cable (belt), you also need to prepare the corresponding holes. Place the prepared pulley on the flywheel and fix it with the bolt. Mark the locations corresponding to the pulley holes. Twist the bolt and separate the parts. Now carefully drill holes in the flywheel. Reconnect the parts and tighten the fixing bolts. The flywheel and crankshaft must be sharpened from the inside. to exclude the possibility of clinging and beating parts against each other. The system is ready. Place it in place in your machine. Connect the cables, while taking them away from rubbing parts.

    If you have a small unit, the belt option may also suit you. Take two sturdy V-shaped belts with a length of about 140 cm. The B-profile is ideal. Open the gearbox and install a pulley on its main shaft. Install the tandem roller on the spring loaded bracket. Note that a minimum of 8 bracket links must be associated with the clutch release pedal. And a double roller is needed to ensure the necessary tension on the belts during operation and to loosen them in the event of slipping / idling. To minimize the wear of elements, provide in the design block-stops for idle operation of the motor.

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    Do not forget to connect the gearbox to the system, it is better to use a new one, but you can also use a used car part, for example, “Oki”.

    Consider another way to independently design a clutch system. Attach a flywheel to the engine. Then connect the clutch system removed from the car using an adapter that can be made from the crankshaft from the Volga. Secure the flywheel to the engine crankshaft. Place the clutch basket with the pallet facing up. Check that the dimensions of the shaft flange mountings and the basket plates are identical.

    If necessary, increase the required clearances with a file. The gearbox and gearbox can be removed from the old unnecessary car (check the serviceability and general condition). Assemble the entire structure and test its operation.

    When making your own motoblock systems, do not forget about an important point: the parts of the unit’s units should not cling to the soil (except for wheels, of course, and tools for tillage).

    You can find out more about how the overhaul of the clutch of a heavy walk-behind tractor takes place.

    Once upon a time, while studying at the Moscow Automotive Institute (MAMI), I, like all other students, had to do course projects. However, it was not very interesting for me to construct “something theoretical”, mostly abstract and not needed by anyone, so I always tried to get an assignment to develop a real unit or unit that could be manufactured and then used in life. One such topic was the automatic dry clutch for small agricultural machines. And now, many years later, when I had the need to urgently replace the V-belt drive of a household mini-tractor with a more reliable chain drive, I suddenly remembered that long-standing work of mine. It took a clutch! I rummaged in an old portfolio, found the institute’s sketches, modified them a little and took up the tools. This time I did not calculate any theory, only “pure practice”, the main criteria of which were the use of ready-made basic parts, manufacturability, available in conditions “almost on the knee,” and the speed of production. All work took one daylight.

    The automatic centrifugal dry clutch is installed directly on the crankshaft of the engine (in this case, the Honda GX engine, which has many analogues) without any additional modifications. The structure does not require any adjustments or special maintenance. It is collapsible and has good maintainability and can be used in transmissions not only of motoblocks and tractors, but also on snowmobiles, karts, motor scooters, small cars.

    The standard clutch from the Honda Dio scooter was taken as a basis: its clutch plate was used without changes and a drum that was machined under the original hub. This bushing and flange (positions 5 and 12 on the assembly drawing) are made of steel 45. The drive sprocket of a motorcycle “Minsk” (“Voskhod”) is taken as a drive. a common and affordable part. It was previously thermally tempered, machined (machined) to fit the size of the bushing seat, after which it was hardened. The sprocket is pressed onto the bushing and fixed by welding. In principle, this assembly can be made as a single piece, but the labor intensity would be much higher, so I did not bother with complications.

    The appearance of the unit installed on a homemade mini tractor

    The modified drum is also pressed onto the bushing and secured by welding. The bearing is used light series 6006. In the bushing it is fixed against lateral displacement by punching. The pulley was taken from the auxiliary equipment (generator or hydraulic pump) belt drive previously installed on the tractor. For particularly severe operating conditions, instead of a pulley, it is possible to install an additional bearing on the engine shaft, which serves to unload the standard bearing of the internal combustion engine crankshaft. If you refuse to use a pulley, then the clutch will be very compact, within the dimensions of the engine shaft.

    Centrifugal clutch. Assembly drawing: 1. pulley; 2. bearing 6006; 3. Honda Dio clutch plate (assembled unchanged); 4. Honda Dio drum; 5. bushing; 6. motor shaft (diameter 19 mm); 7. key; 8. washer; 9. screw М8х35; 10. washer; 11. sprocket (15 teeth from the motorcycle “Minsk” or “Voskhod”); 12. flange; 13. bushing

    Oddly enough, but the most difficult stage in my garage conditions was the manufacture of a keyway on the flange (position 12). I had to think not only about the design, but also about the technology. For this, a stock with a transitional fit was machined. It was inserted into the flange and, using a drilling machine (not a hand drill!), A hole with a diameter of 5 mm was made at the junction of these parts. Then, with a flat file (its narrow side edge), the semicircular groove was brought to the desired rectangular shape.

    A similar operation was carried out with the driven sprocket of the drive.

    Automatic centrifugal dry clutch

    The running tests of the clutch have shown good results. The four-wheel drive tractor confidently moved through the spring softened snow in fourth gear. The speed range varied from 3 to 15 km / h, while the clutch housing remained cold. The moment of its triggering was also acceptable.

    It was not without testing for maximum load: I buried the tractor in a tree with the bridges and locks on. the wheels slipped confidently, and the heating of the clutch remained within acceptable limits. And demonstrating the device to neighbors and friends, I laugh. I say that once again, now in practice, I defended my old course project. In a word, it was not in vain that I studied!

    The clutch is one of the most important elements of a modern walk-behind tractor, the main function of which is to transfer torque from the crankshaft of the unit to its gearbox. It is the high-quality clutch available in the design for the walk-behind tractor that allows the agricultural unit to move smoothly and, if necessary, stop without the need to completely turn off the motor.

    Regardless of the class of the walk-behind tractor, the clutch in its standard design consists of the same parts.

    • adjustment and control unit;
    • driving mechanism;
    • driven elements.

    When the mechanism is locked, a signal is generated by the spin levers. At the same time, the latter disconnects the driven element from the pressure plate, the result of which is the complete disconnection of the existing clutch in the walk-behind tractor device.

    The automatic clutch of a household walk-behind tractor is equipped with a bearing that plays the role of a friction reducer. Due to its presence, during the operation of the walk-behind tractor, the levers rotate without touching each other and with a fixed layering. A spring built into the clutch mechanism ensures that the control unit returns to its original position after each shift cycle.

    DIY centrifugal clutch for walk-behind tractor

    Motoblocks greatly facilitate the work of farmers and owners of their own backyard plots. This article will focus on such an important structural element of this unit as the clutch.

    How to make a hitch on a uniaxial tractor. sequence of actions

    The principle of operation of the clutch system, regardless of its type, is based on constant friction of parts. As a result, the unit quickly fails. Buying a new high-quality mechanism is not a cheap pleasure, and therefore many enthusiastic farmers prefer to make a clutch system with their own hands. This is not as difficult as it might seem at first glance, but before work, you still need to thoroughly prepare.

    The first thing to do is study the detailed drawings of the mechanism. They must indicate the dimensions of each of the parts and the place of its installation in the structure.

    After studying the scheme, you need to prepare materials and tools available in the garage.

    To assemble the clutch, it will be necessary:

    • input shaft and a serviceable flywheel. as a rule, these parts are taken from the checkpoint of the Soviet Moskvich car;
    • a driven pulley on which two handles are pre-installed;
    • an intact hub and a metal fist of a swivel type from a Tavria car;
    • B-profile;
    • a whole crankshaft from a GAZ-69 car.

    The correct procedure for assembling the clutch mechanism for an existing walk-behind tractor is as follows:

    • First, you need to carefully grind off the taken crankshaft. As a result of the revision, the part should not touch other elements of the produced clutch of the walk-behind tractor;
    • Then it is necessary to install the factory hub of the walk-behind tractor on the used shaft;
    • On the surface of the shaft, you will need to arrange a place for mounting the bearings. After recessing the space, the hub must be mounted without any gaps. In this case, the driven pulley must certainly rotate directly around its axis without the slightest hindrance;
    • At the next stage, 6 identical holes must be made in the pulley, the diameter of each of which should not exceed 5 mm. The distance between the holes must be the same. It should be noted that bolts must be screwed into the holes, each 10 mm long. Because of this, holes will also need to be made on the back of the pulley;
    • Next, the pulley should be positioned above the flywheel and both parts should be fixed together with a bolt. Then you will need to mark the places for drilling holes. in the future, the latter should coincide with the holes previously made in the pulley;
    • After that, you need to pull out the pulley and drill holes in those places of the flywheel where the marks were previously set;
    • After that, you will need to grind the inner surfaces of the shaft and the flywheel available in the design so that both parts do not touch each other;
    • The clutch design must necessarily include the clutch handle for a uniaxial tractor. To do it, you should use a pipe with a diameter of about 1 cm and a length of 3 cm. In the future, the lever must be fixed on the surface of the pulley;
    • To complete the mechanism, you will need a clutch cable for the walk-behind tractor. For this purpose, you can purchase a new cord, then wind it on any reel, or take a whole cable with a serviceable reel from a household chainsaw.

    The self-made clutch made in this way is optimal for completing the motoblocks of the well-known brands Agro and Neva MB-2. A self-made mechanism will last a long enough time without the need for repairs.