The motoblock clutch is an important transmission element, through which the engine crankshaft transmits torque to the gearbox mechanisms. With the help of this part, during the gear change, the motor and gearbox are separated. It is due to the participation of the clutch that the walk-behind tractor smoothly moves off, and also stops without completely turning off the engine.
Clutch functions in the design of a walk-behind tractor
The operation of the clutch is based on the action of the friction clutch. This transmission element performs several important functions, among which stands out:
- Uninterrupted torque transmission;
- Suppression of torsion vibrations;
- Smooth switching of speeds;
- Impactless gear connection;
- Connecting and disconnecting a gearbox with an internal combustion engine;
- Disconnecting the transmission from the flywheel device.
The clutch device makes it possible to briefly turn off the crankshaft of the engine and the power transmission of the machine. Thanks to the clutch, the technique starts and stops the movement smoothly and without jerks.
Centrifugal clutch - device and advantages
This kind of element is worth highlighting among other designs due to its reliability and durability. It is used in checkpoints. automatic type. 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 to improve the maneuverability of the equipment and ensure smooth movement in corners.
Together with the clutch, the differential regulates the rotation of the wheels of the walk-behind tractor at different speeds. Moreover, the mechanisms that transmit power together act as wheel locks. In some models of equipment, instead of a differential, they install special device, which blocks one of the wheels of the walk-behind tractor at the command of the driver.
More modern models of equipment are equipped with a friction clutch. It is mounted between the motor and gearbox. In this design, the driven parts are closely connected with the input shaft of the gearbox, and the leading parts are connected with the crankshaft of the motor. In most cases, both driving and driven elements are made in the form of flat round discs, or in the form of a cone. Just like centrifugal, friction clutch is put into operation by manipulating a separate handle.
The principle of operation of the clutch
The clutch for a walk-behind tractor consists of several important elements:
- control devices;
- leading element;
- driven details.
The leading part consists of the front side of the engine flywheel and the pressure plate. The disc rotates with the attached flywheel. At the same time, the disk can also move along the axis with respect to the flywheel. Between these two elements is a driven disk, which is located on the driven shaft. Along the perimeter of the pressure plate are spring elements in the form of cylinders.
The function of the springs is based on the compression of the disk they support. 
In this case, the other end of the springs is in contact with the casing. Thus, the springs maintain the clutch for the walk-behind tractor in a constant on state.
The control mechanism is made of release levers connected to the pressure plate housing by means of pull rods and a pedal. By disengaging the clutch, the owner of the walk-behind tractor engages the clutch cable, which transfers force to the release levers. When the springs are compressed, the levers move the driven disk away from the pressure one, which leads to the disengagement of the clutch.
The bearing reduces friction by preventing the fixed taper from touching the rotation levers. Most models of walk-behind tractors are equipped with three levers located at an angle of 120 degrees with respect to each other. With the help of a spring, each clutch lever returns to initial position. In this case, the layering moves to the distance necessary to turn off the levers. If this distance is not reached, then the clutch begins to slip.
How to make a clutch mechanism with your own hands?
The clutch on the walk-behind 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 with your own hands. The design of a homemade clutch will be composed of:
- the input shaft of the gearbox and the flywheel of the Moskvich car;
- hub and knuckle from Tavria;
- B-profile;
- Two stream driven pulley;
- Crankshaft from GAZ-69.
Subsequent work on the assembly of the mechanism is as follows:
- First you need to grind off the crankshaft so that it does not cling to other elements of the walk-behind tractor;
- We put the regular hub of the walk-behind tractor on the shaft;
- Next, on the shaft, it is necessary to machine a place for the bearing. This operation should be carried out as precisely 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 its reverse side;
- Next, with a drill with a 5 mm drill, make 6 holes in the pulley. The distance between them must be the same. Since 10 mm bolts will be used, holes must also be drilled on the back of the wheel that drives the drive belt;
- Next, install the pulley on the flywheel, and tighten both parts with a bolt. After that, mark the drilling locations on the flywheel so that they coincide with the 6 holes in the pulley;
- Remove the pulley and drill holes in the flywheel;
- After that, put the pulley back on and securely tighten the structure with bolts;
- Machine the inner surface of the crankshaft and flywheel so that they do not beat against each other.
The finished structure can be installed in 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.
Being integral part transmission, the clutch of the walk-behind tractor performs the function of transmitting torque from the crankshaft of the motor to the gearbox (gear shaft). With its help, during gear shifting, the power plant and the gearbox are separated. Due to this mechanism, the walk-behind tractor or motorized dome moves off and stops without turning off the motor.
If the intended design of factory-made motorcycles does not provide for the clutch, you can assemble it yourself.
1 General information
The clutch is based on the action of a friction clutch (sliding friction force). This transmission component is intended for:
- torque transmission;
- damping of torsional vibrations;
- smooth gear shifting;
- shockless connection of gears;
- connection and short-term disconnection of the connection between the internal combustion engine and the gearbox;
- 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 walk-behind tractor, with the help of a clutch, starts to act without jerking. Of great importance for agricultural vehicles when driving, the clutch allows you to move off (although it is possible to do this without it, but it is very difficult).
The centrifugal clutch has proven itself as a reliable transmission component. 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 sleeve, a bearing, a retaining ring.
An important role is also played by the differential, which is directly related to the clutch. It is entrusted with the tasks of improving the maneuverability of heavy-duty walk-behind tractors and ensuring smooth turning. The clutch and differential in "symbiosis" regulate the rotation of the wheeled part of the walk-behind tractor with different speed. In addition, power transmission mechanisms are equipped with wheel blocking functions. However, in some models, the differential is replaced with a special device that disables one wheel when driving.
On modern models walk-behind tractors usually use 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 elements are connected with the engine crankshaft. As a rule, the leading and driven elements are produced in the form of round flat disks, sometimes they are made in a conical variation (for example, BChS-735 and Kataisi Super-600 walk-behind tractors) 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 you to set their position, the degree of tension from the belt control rod, smoothly disconnect and connect the engine to the transmission.
1.1 Device and principle of operation
The friction type clutch consists of:
The driving part is formed from the end surface of the motor flywheel and the pressure plate, which rotates with the flywheel. However, the disk can also move in the axial direction relative to the flywheel. Between them is a driven disk, its hub is located on a splined driven shaft. Around the circumference of the pressure plate are coil springs installed with pre-compression.
The role of the springs is to press the pressure plate, against which they rest at one end, and at 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 on state.
The control mechanism includes squeezing levers, which are connected to the pressure plate by rods and a lever 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 with a release bearing. The outer end connected to the pressure plate by bolts, the levers, during the compression of the springs, divert the driven discs from the pressure plate, due to which the clutch is disengaged.
The bearing reduces friction by eliminating the contact between the fixed side and the rotating arms. Usually there are three levers in the configuration, placed at an angle of 120 degrees to each other. With the help of a spring, the parts of the control mechanism return to their original position. The layer is separated by the amount of clearance from the levers necessary to completely disengage the clutch. If this distance is not respected, the clutch will slip and the friction linings will wear out. When the gap exceeds the required distance, the clutch will not disengage completely.
2 Types of clutch, their features
Depending on the design characteristics of motorcycles, the clutch for a walk-behind tractor can be of the following types:
- frictional (discussed above);
- electromagnetic;
- hydraulic;
- centrifugal;
- belt;
- one-, two-disk;
- multidisk.
According to the type of friction, the considered mechanism is classified into wet, operating in an oil bath, and dry, functioning in an air environment. In accordance with the switching mode, a permanent closed and non-permanently closed clutch is distinguished.
Centrifugal works due to the following working bodies: clutch cable, transmission input shaft, flywheel, clutch lever, release bearing, handle, driven disk, engagement lever, stem fungus, lock washer, turn off plugs. Centrifugal devices have not found wide application due to their tendency to slip, which is characteristic under loads, and wear of friction surfaces.
At hydraulic system through the connecting rod, when the pedal is pressed, the movement is transmitted to the piston, which pushes the hydraulic fluid through a special channel. The piston under the pressure of the working medium acts on the lever through the connecting rod. It springs back to its original position.
The multi-disk and single-disk principle of operation practically do not differ from each other. The advantages of the first are based on the small dimensions of the friction discs, the smooth engagement of the clutch. The disadvantages are worst conditions cooling, problems in obtaining the purity of inclusion. Double-disk mechanisms are installed in connection with big power power unit, the need to transmit increased torque, to increase service life.
The belt-driven clutch, which ensures the transmission of torque from the motor to the gearbox, is considered one of the first and inferior to the mechanisms listed above, because. has a number of disadvantages: high level wear, unreliability, low efficiency, impracticality when working with powerful engines.
2.1 Clutch upgrade
Since the principle of operation of the device provides for serious friction component parts, natural wear and tear cannot be avoided. You can make a clutch on, but 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 input shaft of the Moskvich car box, a steering knuckle with a hub from Tavria, profile B, a driven pulley for two streams and a steel billet as a crankshaft (suitable for GAZ-69). homemade product begins with the turning of a steel billet lathe in order to put a hub on the resulting false shaft. After landing the pulley on the honed shaft, it should be machined seat according to the diameter on the inner ring of the pulley for the thrust bearing, which should “sit down” 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 with reverse side. At the next stage, in the pulley, using a drill and a drill (5 mm), make 6 holes equidistant from each other. Since the bolts will be 10 mm, on the reverse side it is necessary to drill holes in 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 for fixing. While the pulley is on the flywheel, mark the flywheel through the holes made on it earlier. Remove your pulley and drill all 6 holes.
Using bolts (10 mm) tighten the structure, the thread without a cap should be 60 mm. Turn the crankshaft inside with a blank. To prevent the flywheel from making shocks, it is also necessary to machine its surface, and then center it along the mounting hole.
It may be necessary to trim the inner plane of the flywheel along with the pulley a little on a lathe. The metal layer is removed no more than 1 m. Having previously seated the flywheel for shipment, check the runout of the planes, it should not exceed 0.1 mm. Ultimately, it remains to mount the basket on the flywheel.
2.2 Overhaul of the clutch of a heavy walk-behind tractor (video)
Currently in agriculture and gardening, special equipment is often used. Here, equipment such as a walk-behind tractor stands out separately. These devices allow you to quickly and efficiently process the soil. However, like any type of equipment, such equipment can also fail. Important components of this apparatus are the motor and transmission. These two components work together, while pairing is carried out through a clutch disc for an Agro walk-behind tractor or other type of equipment. In this case, it is required to consider in detail how the clutch is replaced and repaired on the Agro walk-behind tractor.
You can repair the clutch in this walk-behind tractor yourself
The design and principle of operation of the element
This mechanism, which, at first glance, has complex structure, in practice consists of only a few elements, namely:
- Release bearing.
- The basket where the disks are installed.
- Directly the disk, which, under pressure, diverges into several separate components.
Also noteworthy is the presence couplings and traditional bolt clamps, due to which the structure is mounted on the working plane. The clutch assembly is mounted above the transmission. This fixture allows the main gear of the engine to smoothly align with the gear of the gearbox.
In the absence of a hitch or its damage, switching becomes difficult, and at the moment of switching on, a metallic crackle is heard, since during operation it is difficult for the gears to align at different speeds. In this case, the smoothness of switching is provided by the handle, from which the cable goes to the mechanism itself. This handle is released when switching.
In this video you will learn how to repair the clutch:
Important! Despite the simplicity of the mechanism, it cannot be said that the element can be easily replaced or repaired; in order to restore or change the structural component, you need to have some skills and experience.
DIY repair
To repair the clutch of the Agro walk-behind tractor with your own hands, first of all, you should understand what kind of malfunction we are talking about, since a number of damages cannot be repaired at all and require replacement of the consumable item. Consider the main options for malfunctions:
- the release cable has flown off (to eliminate this breakdown, you need to check the device for integrity, and then fix it in the same place, you do not need to disassemble the mechanism for this);
- the basket is damaged (these products are made of steel or cast iron, so when minor deformations straightening can be performed, for this it is necessary to completely remove the structural element);
- the release bearing jammed (here you need to squeeze the tension cable and try to return the device to its place, while dismantling the entire mechanism is not required).
If the ceramic disc is damaged, the basket has burst or is severely deformed, and the release bearing is worn out, then repairing the part is unreasonable, as replacement is required. structural element, while completely changing the clutch of the Agro walk-behind tractor is not necessary.
Important! To replace any consumable item, you need to completely dismantle the device from the walk-behind tractor.
Adjustment
In the process of long operation, this mechanism gradually wears out, which requires adjustment. Let's consider in more detail how this procedure is performed:
- First of all, you should choose a comfortable and spacious place;
- it is necessary to disconnect the clamps;
- it is required to release the tension cable;
- then you need to lubricate everything with a special substance;
- after that, the cable is pulled, and the spring is shortened;
- the bearing needs to be rotated to a more suitable position.
During the adjustment process, it is necessary to adjust the length of the cable so that squeezing the handle does not require much effort.
Important! When adjusting (adjusting) the clutch of the walk-behind tractor, it is imperative that the elements be lubricated, otherwise there is a risk that the tensioner will break or will again be poorly squeezed out.
Product replacement
Changing this device is the most costly process by financial standards. Although it is not necessary to change all components, experts recommend doing this at the same time. Let's see how the procedure is performed:
- First of all, parts are bought.
- Next, you need to completely dismantle the old product.
- All latches are completely removed, and the tension cable is removed.
- After that, you need to clean the landing site.
- Further, new parts are assembled into a single mechanism.
- The device is mounted on the seat.
- The tensioner is connected to the release bearing through a spring.
- The whole structure is fixed with fasteners.
At first glance, this is not difficult, but the process is complicated by the fact that it is necessary to remove the latches, which also partially hold the transmission.
Important! Experts recommend replacing the entire device based on practice, since over time the parts are rubbed and ground, which is why it is quite difficult to combine a new disk and an old basket, or vice versa.
The clutch is an integral element of the transmission, the task of which is to transfer the torque received by the crankshaft to the gearbox and disconnect the gearbox from the engine when switching the speeds of the walk-behind tractor. It is thanks to the presence of this mechanism that the agricultural machine starts off smoothly and can stop without completely turning off the engine.
Clutch for walk-behind tractor - design and principle of operation
The clutch of absolutely any agricultural machine consists of a number of elements. The design of the mechanism includes:
- Permanent control device;
- host node;
- driven components.
The design of the control mechanism includes a release lever connected to the pressure disc by means of a pedal release and rods. When the implement's clutch device is blocked, a signal is generated that the release levers receive. They, in turn, disconnect the driven disk from the pressure housing, as a result of which the mechanism is turned off.
The bearing in the clutch assembly of a modern walk-behind tractor serves to reduce friction, excluding, at the same time, the contact of the levers rotating around its axis and a completely motionless layer. The spring is responsible for returning the control mechanisms to their original position. The layer, in this case, is repelled from the levers to the distance required for the final shutdown.
Types and description of motoblock clutch mechanisms
Depending on the design features of motoblocks, agricultural units can be equipped with the following types of clutch:
According to their type of friction, clutch mechanisms are divided into dry, as well as devices operating in air or in a bath of engine oil. Depending on the initial starting mode, a non-permanently open and permanently closed clutch is found on sale.
Do-it-yourself clutch for a walk-behind tractor
Regular operation of the clutch system implies constant friction of its parts, which is why even the most reliable mechanism sooner or later becomes unusable. After that, you can buy a new device, or try to make a homemade clutch for an agricultural machine.
Before you make a clutch on a walk-behind tractor, you will need to prepare certain parts. For work you will need:
- Flywheel and input shaft taken from a gearbox from a Soviet Moskvich;
- Swivel fist and serviceable hub from auto Tavria;
- Driven pulley equipped with two handles;
- Crankshaft from a GAZ-69 car;
- B-profile.
- First, grind down the used crankshaft so that it does not touch other internal elements of the device;
- Next, put the regular hub of your walk-behind tractor on the shaft;
- Machine a place in the surface of the shaft to install the bearing. As a result, the hub must be installed without the slightest gaps, and the pulley itself must rotate freely around its axis;
- After that, turn the crankshaft over and do the above steps on its reverse side;
- Then make 6 holes in the pulley using a drill with a 5mm bit. The holes must be evenly spaced. Keep in mind that 10mm bolts will be screwed into the holes, so you also need to drill holes on the back of the pulley;
- Install the pulley over the flywheel, and fasten both parts with a bolt. Next, mark the places where you need to drill holes. Note that they must match the holes previously drilled in the pulley;
- Pull out the pulley and drill small holes in the flywheel;
- Machine the surface inside the flywheel and shaft so that the parts do not touch each other;
- The mechanism should include a clutch handle on the walk-behind tractor. To make it, take a pipe, 30 long and about 10 mm in diameter, and fix it on a pulley;
- The motoblock clutch cable can be taken from old chainsaw, or buy a new cord, and wind it on a reel.
A self-made clutch is suitable for installation on Agro, Neva MB-2 walk-behind tractors and agricultural vehicles of other brands.
The clutch is tightly interconnected with the gearbox. It performs quite important functions. Namely, it transmits torque from the crankshaft to the gearbox located in the transmission, disconnects the gearbox and the crankshaft (this is done when shifting gears). And this mechanism also ensures the smooth running of the walk-behind tractor from a standstill. Thanks to him, it is possible to stop the equipment without turning off the engine (this is possible through the clutch lever, cable and the entire system as a whole).
What types exist
Depending on the design features walk-behind tractor, the mechanism in question can be of the following types:
- frictional;
- hydraulic;
- electromagnetic;
- centrifugal;
- single disk;
- two-disk;
- multidisk;
- belt.
A centrifugal clutch is used to solve various problems, one of which is to facilitate the control of a walk-behind tractor. The clutch provides a smooth start of movement, since the pressure on the clutch disc is automatic.
It includes the following accessories:
- clutch cable;
- flywheel;
- release bearing;
- switching lever;
- clutch lever mounted on a walk-behind tractor;
- transmission input shaft;
- driven disk;
- pen;
- lock washer;
- stem fungus;
- shutdown plug.
By the way, if the owner of the walk-behind tractor does not have experience in plumbing, then he will not be able to make a clutch with his own hands. You can only replace or repair it.
The important role of the differential
Since this mechanism is part of the transmission, it means that it is associated with the clutch. The differential has a difficult purpose - the implementation of smooth turns, as well as improving the maneuverability of heavy walk-behind tractors. The purpose of the clutch for the walk-behind tractor and the differential is to adjust the rotation of both wheels at different speeds. In addition, power transmission mechanisms can be equipped with wheel blocking functions. However, instead of a differential, a special device can be installed that allows you to turn off one wheel when driving.
Extensive functionality
The grip on the walk-behind tractor is of great importance when driving. Without it, it is difficult to move off, although it is possible. If it is out of order, then it is better to immediately repair it. A broken clutch for a walk-behind tractor in a manual gearbox leads to damage to the entire transmission. In this sense, the centrifugal clutch has proven itself better, since it has found application in automatic boxes gears. If it fails, then the walk-behind tractor will not budge at all, which means it will not entail other breakdowns.
Part centrifugal clutch for a light walk-behind tractor includes:
- flywheel;
- hub with locking groove and key;
- pulley;
- flange;
- bearing;
- sleeve;
- retaining ring;
- casing.
Making a clutch for a heavy or light walk-behind tractor with your own hands requires certain knowledge and experience. If you have them, then start right now. For reliable operation of the centrifugal type, it is necessary to reduce the weight of the pads to 110 grams. Initially, each of them weighs 134 grams. It is necessary to remove the rubber rings from under the pads, and install rigid springs in their place.
Motoblock controls
This is a system of mechanisms that allows you to change the speed, as well as the direction of movement of the walk-behind tractor. The controls include the steering wheel, clutch and shift levers, throttle position knob and more. Since the walk-behind tractors do not provide a seat for the operator, it means that the maneuvering of such equipment is provided with the help of hands. But, if you can buy a trolley with a seat in a specialized store, you get a mini-tractor.
